The Experts below are selected from a list of 2757 Experts worldwide ranked by ideXlab platform
Gross James - One of the best experts on this subject based on the ideXlab platform.
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Statistical Guarantee Optimization for AoI in Single-Hop and Two-Hop Systems with Periodic Arrivals
'Institute of Electrical and Electronics Engineers (IEEE)', 2020Co-Authors: Champati, Jaya Prakash, Al-zubaidy Hussein, Gross JamesAbstract:Age of Information (AoI) has proven to be a useful metric in networked systems where timely information updates are of importance. In the literature, minimizing "average age" has received considerable attention. However, various applications pose stricter age requirements on the updates which demand knowledge of the AoI distribution. Furthermore, the analysis of AoI distribution in a multi-hop setting, which is important for the study of Wireless Networked Control Systems (WNCS), has not been addressed before. Toward this end, we study the distribution of AoI in a WNCS with two hops and devise a problem of minimizing the tail of the AoI distribution with respect to the frequency of generating information updates, i.e., the sampling rate of monitoring a process, under first-come-first-serve (FCFS) Queuing Discipline. We argue that computing an exact expression for the AoI distribution may not always be feasible; therefore, we opt for computing upper bounds on the tail of the AoI distribution. Using these upper bounds we formulate Upper Bound Minimization Problems (UBMP), namely, Chernoff-UBMP and alpha-relaxed Upper BoundMinimization Problem (alpha-UBMP), where alpha > 1 is an approximation factor, and solve them to obtain "good" heuristic rate solutions. We demonstrate the efficacy of our approach by solving the proposed UBMPs for three service distributions: geometric, exponential, and Erlang. Simulation results show that the rate solutions obtained are near-optimal for minimizing the tail of the AoI distribution for the considered distributions.Comment: Published in IEEE Transactions on Communications. This is an extension to the following workshop paper for two-hop and N-hop scenarios. J. P. Champati, H. Al-Zubaidy, and J. Gross, "Statistical guarantee optimization for age of information for the DG1 queue", in Proc. IEEE INFOCOM Workshops, April 2018, pp. 130-13
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Statistical Guarantee Optimization for Age of Information for the D/G/1 Queue
'Institute of Electrical and Electronics Engineers (IEEE)', 2018Co-Authors: Varma Champati, Jaya Prakash, Al-zubaidy Hussein, Gross JamesAbstract:Age of Information (AoI) has proven to be a useful metric in networked systems where timely information updates are of importance. Recently, minimizing the "average age" has received considerable attention. However, various applications pose stricter age requirements on the updates which demand knowledge of the AoI distribution. In this work, we study the distribution of the AoI and devise a problem of minimizing the tail of the AoI distribution function with respect to the frequency of generating information updates, i.e., the sampling rate of monitoring a process, for the D/G/1 queue model under FCFS Queuing Discipline. We argue that computing an exact expression for the AoI distribution may not always be feasible. Therefore, we opt for computing a bound on the tail of the AoI distribution and use it to formulate a tractable alpha-relaxed Upper Bound Minimization Problem (alpha-UBMP), where alpha > 1 is an approximation factor. This approximation can be used to obtain "good" heuristic solutions. We demonstrate the efficacy of our approach by solving alpha-UBMP for the D/M/1 queue. We show, using simulation, that the rate solutions obtained are near optimal for minimizing the tail of the AoI distribution.QC 20190107
Bernard Cousin - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of Gateway-Based Shaping Methods for HTTP Adaptive Streaming
2015Co-Authors: Chiheb Ben Ameur, Emmanuel Mory, Bernard CousinAbstract:HTTP Adaptive Streaming (HAS) is a streaming video technique commonly employed over best-effort networks. However, it is characterized by some issues that harm its quality of experience (QoE) in cases of daily use. The main use case of the present investigation involves HAS clients competing for bandwidth inside the same home network. Based on related work, we found that one of the most convenient solutions for this use case is to define a bandwidth manager, on the gateway side, that divides the available home bandwidth between HAS clients. Two main methods have previously been proposed to shape the HAS streams in accordance with the bandwidth manager's direction and are referred to as gateway-based shaping methods: a highly renowned method, Hierarchical Token Bucket Method (HTBM), that uses the hierarchical token bucket Queuing Discipline, and another method, Receive Window Tuning Method (RWTM), that employs TCP flow control by handling only acknowledgment TCP packets. In this paper, we compare these two shaping methods. Results indicate that RWTM improves the QoE better than HTBM and does not add Queuing delay. Results were validated through experimentation and objective QoE analytical criteria.
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Evaluation of gateway-based shaping methods for HTTP Adaptive Streaming
2015 IEEE International Conference on Communication Workshop ICCW 2015, 2015Co-Authors: Chiheb Ben Ameur, Emmanuel Mory, Bernard CousinAbstract:? 2015 IEEE.HTTP Adaptive Streaming (HAS) is a streaming video technique commonly employed over best-effort networks. However, it is characterized by some issues that harm its quality of experience (QoE) in cases of daily use. The main use case of the present investigation involves HAS clients competing for bandwidth inside the same home network. Based on related work, we found that one of the most convenient solutions for this use case is to define a bandwidth manager, on the gateway side, that divides the available home bandwidth between HAS clients. Two main methods have previously been proposed to shape the HAS streams in accordance with the bandwidth manager's direction and are referred to as gateway-based shaping methods: a highly renowned method, Hierarchical Token Bucket Method (HTBM), that uses the hierarchical token bucket Queuing Discipline, and another method, Receive Window Tuning Method (RWTM), that employs TCP flow control by handling only acknowledgment TCP packets. In this paper, we compare these two shaping methods. Results indicate that RWTM improves the QoE better than HTBM and does not add Queuing delay. Results were validated through experimentation and objective QoE analytical criteria.
Euthemia Stavrulaki - One of the best experts on this subject based on the ideXlab platform.
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capacity and price setting for dispersed time sensitive customer segments
European Journal of Operational Research, 2008Co-Authors: Michael S Pangburn, Euthemia StavrulakiAbstract:Abstract We consider joint pricing and capacity decisions for a facility serving heterogeneous consumers that span a continuous range of locations, and are sensitive to time delays. Within this context, we analyze two contrasting service strategies: segmentation and pooling. Consumer segments differ with respect to their reservation prices and time sensitivities, and are dispersed over a single distance dimension. The firm serves these consumers using a process that we initially model as an M/M/1 Queuing system. We analyze profit-maximizing price and capacity levels for a monopolist, and contrast the optimal segmentation and pooling policies. We find that when consumers are time sensitive, and can expect Queuing delays at the firm’s facility (due to random arrival and service times), then scale economies from pooling can outweigh segmentation benefits. Yet, segmentation outperforms pooling when consumer segments differ substantively, in which case the firm can use capacity as a lever to price discriminate between the segments. Moreover, by contrasting a dedicated-services strategy, which directly targets specific segments and serves them separately, with the alternative of allowing consumers to self-select, we find that self-selection has a moderate negative influence on profits. We also examine the profit impact of employing alternative Queuing systems, and find that a hybrid strategy based on a prioritized Queuing Discipline, that combines elements of segmentation (by offering different waiting times) and pooling (by sharing capacity across consumer segments), can outperform both the pure segmentation and pooling strategies.
Geyong Min - One of the best experts on this subject based on the ideXlab platform.
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performance modelling of priority Queuing Discipline under self similar and poisson traffic
Local Computer Networks, 2007Co-Authors: Xiaolong Jin, Geyong MinAbstract:The priority queueing Discipline plays a crucial role in the differentiated services (DiffServ) architecture. Analytical modelling and performance evaluation of priority queueing systems have received significant research efforts in the telecommunication community. However, most existing studies have primarily focused on the analysis of such systems under either short range dependent (SRD) or long range dependent (LRD) traffic only. With the aim of investigating the impact of heterogeneous traffic on the design and performance of telecommunication networks, this paper presents an analytical model for priority queueing systems subject to heterogeneous LRD self-similar and SRD Poisson traffic. We extend the application of the generalized Schilder's theorem to deal with heterogeneous traffic and further develop the analytical upper and lower bounds for the queue length distributions of individual traffic flows. Through extensive comparisons between analytical bounds and simulation results, we validate the effectiveness and accuracy of the developed model.
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LCN - Performance Modelling of Priority Queuing Discipline under Self-Similar and Poisson Traffic
32nd IEEE Conference on Local Computer Networks (LCN 2007), 2007Co-Authors: Xiaolong Jin, Geyong MinAbstract:The priority queueing Discipline plays a crucial role in the differentiated services (DiffServ) architecture. Analytical modelling and performance evaluation of priority queueing systems have received significant research efforts in the telecommunication community. However, most existing studies have primarily focused on the analysis of such systems under either short range dependent (SRD) or long range dependent (LRD) traffic only. With the aim of investigating the impact of heterogeneous traffic on the design and performance of telecommunication networks, this paper presents an analytical model for priority queueing systems subject to heterogeneous LRD self-similar and SRD Poisson traffic. We extend the application of the generalized Schilder's theorem to deal with heterogeneous traffic and further develop the analytical upper and lower bounds for the queue length distributions of individual traffic flows. Through extensive comparisons between analytical bounds and simulation results, we validate the effectiveness and accuracy of the developed model.
Chiheb Ben Ameur - One of the best experts on this subject based on the ideXlab platform.
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TCP Protocol Optimization for HTTP Adaptive Streaming
2015Co-Authors: Chiheb Ben AmeurAbstract:HTTP adaptive streaming (HAS) is a streaming video technique widely used over the Internet for Video on Demand (VoD) and Live streaming services. It employs Transmission Control Protocol (TCP) as transport protocol and it splits the original video inside the server into segments of same duration, called "chunks", that are transcoded into multiple quality levels. The HAS player, on the client side, requests for one chunk each chunk duration and it commonly selects the quality level based on the estimated bandwidth of the previous chunk(s). Given that the HAS clients are located inside access networks, our investigation involves several HAS clients sharing the same bottleneck link and competing for bandwidth inside the same home network. Here, a degradation of both Quality of Experience (QoE) of HAS users and Quality of Service (QoS) of the access network are often recorded. The objective of this thesis is to optimize the TCP protocol in order to solve both QoE and QoS degradations. Our first contribution consists of proposing a gateway-based shaping method, that we called Receive Window Tuning Method (RWTM); it employs the TCP flow control and passive round trip time estimation on the gateway side. We compared the performances of RWTM with another gateway-based shaping method that is based on Queuing Discipline, called Hierarchical Token Bucket shaping Method (HTBM). The results of evaluation indicate that RWTM outperforms HTBM not only in terms of QoE of HAS but also in terms of QoS of access network by reducing the Queuing delay and significantly reducing packet drop rate at the bottleneck. Our second contribution consists of a comparative evaluation between eight combinations that result from combining two shaping methods, RWTM and HTBM, and four very common TCP variants, NewReno, Vegas, Illinois and Cubic. The results show that there is a significant discordance in performance between combinations. Furthermore, the best combination that improves performances in the majority of scenarios is when combining Illinois variant with RWTM. In addition, the results reveal the importance of an efficient updating of the slow start threshold value, ssthresh, to accelerate the convergence toward the best feasible quality level. Our third contribution consists of proposing a novel HAS-based TCP variant, that we called TcpHas; it is a TCP congestion control algorithm that takes into consideration the specifications of HAS flow. Besides, it estimates the optimal quality level of its corresponding HAS flow based on end-to-end bandwidth estimation. Then, it permanently performs HAS traffic shaping based on the encoding rate of the estimated level. It also updates ssthresh to accelerate convergence speed. A comparative performance evaluation of TcpHas with a recent and well-known TCP variant that employs adaptive decrease mechanism, called Westwood+, was performed. Results indicated that TcpHas largely outperformsWestwood+; it offers better quality level stability on the optimal quality level, it dramatically reduces the packet drop rate and it generates lower Queuing delay.
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Evaluation of Gateway-Based Shaping Methods for HTTP Adaptive Streaming
2015Co-Authors: Chiheb Ben Ameur, Emmanuel Mory, Bernard CousinAbstract:HTTP Adaptive Streaming (HAS) is a streaming video technique commonly employed over best-effort networks. However, it is characterized by some issues that harm its quality of experience (QoE) in cases of daily use. The main use case of the present investigation involves HAS clients competing for bandwidth inside the same home network. Based on related work, we found that one of the most convenient solutions for this use case is to define a bandwidth manager, on the gateway side, that divides the available home bandwidth between HAS clients. Two main methods have previously been proposed to shape the HAS streams in accordance with the bandwidth manager's direction and are referred to as gateway-based shaping methods: a highly renowned method, Hierarchical Token Bucket Method (HTBM), that uses the hierarchical token bucket Queuing Discipline, and another method, Receive Window Tuning Method (RWTM), that employs TCP flow control by handling only acknowledgment TCP packets. In this paper, we compare these two shaping methods. Results indicate that RWTM improves the QoE better than HTBM and does not add Queuing delay. Results were validated through experimentation and objective QoE analytical criteria.
