The Experts below are selected from a list of 142401 Experts worldwide ranked by ideXlab platform
T La Porta - One of the best experts on this subject based on the ideXlab platform.
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Data Dissemination with ring based index for wireless sensor networks
IEEE Transactions on Mobile Computing, 2007Co-Authors: Wensheng Zhang, Guohong Cao, T La PortaAbstract:In wireless sensor networks, sensor nodes are capable of not only measuring real world phenomena, but also storing, processing, and transferring these measurements. Many techniques have been proposed for disseminating sensing Data. However, most of them are not efficient in the scenarios where a huge amount of sensing Data are generated, but only a small portion of them are queried. In this paper, we first propose an index-based Data Dissemination scheme to address the problem. With this scheme, sensing Data are collected, processed, and stored at the nodes close to the detecting nodes, and the location information of these storing nodes is pushed to some index nodes, which act as the rendezvous points for sinks and sources. To address the issues of fault tolerance and load balance, we extend the scheme with an adaptive ring-based index (ARI) technique in which the index nodes for one event type form a ring surrounding the location which is determined by the event type, and the ring can be dynamically reconfigured. Considering that frequently updating or querying index nodes may cause high overhead, we also propose a lazy index updating (LIU) mechanism and a lazy index querying (LIQ) mechanism to reduce the overhead. Analysis and simulations are conducted to evaluate the performance of the proposed scheme. The results show that the proposed scheme outperforms the external storage-based scheme, the DCS scheme, and the local storage-based schemes with flood-response style. The results also show that using ARI can tolerate clustering failures and achieve load balance and using LIU (LIQ) can further improve the system performance. is pushed to some index nodes,
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Data Dissemination with ring based index for wireless sensor networks
International Conference on Network Protocols, 2003Co-Authors: Wensheng Zhang, Guohong Cao, T La PortaAbstract:In current sensor networks, sensor nodes are capable of not only measuring real world phenomena, but also storing, processing and transferring these measurements. Many Data Dissemination techniques have been proposed for sensor networks. However, these techniques may not work well in a large scale sensor network where a huge amount of sensing Data are generated, but only a small portion of them are queried. In this paper, we propose an index-based Data Dissemination scheme to address the problem. This scheme is based on the idea that sensing Data are collected, processed and stored at the nodes close to the detecting nodes, and the location information of these storing nodes is pushed to some index nodes, which act as the rendezvous points for sinks and sources. We further extend the scheme with an adaptive ring-based index (ARI) technique, in which the index nodes for one event type form a ring surrounding the location which is determined by the event type, and the ring can be dynamically reconfigured for fault tolerance and load balance. Analysis and simulations are conducted to evaluate the performance of the proposed index-based scheme. The results show that the index-based scheme outperforms the external storage-based scheme, the DCS scheme, and the local storage-based schemes with flood-response style. The results also show that using ARI can tolerate clustering failures and achieve load balance.
Dik Lun Lee - One of the best experts on this subject based on the ideXlab platform.
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performance evaluation of an optimal cache replacement policy for wireless Data Dissemination
IEEE Transactions on Knowledge and Data Engineering, 2004Co-Authors: Wangchien Lee, Dik Lun LeeAbstract:Data caching at mobile clients is an important technique for improving the performance of wireless Data Dissemination systems. However, variable Data sizes, Data updates, limited client resources, and frequent client disconnections make cache management a challenge. We propose a gain-based cache replacement policy, Min-SAUD, for wireless Data Dissemination when cache consistency must be enforced before a cached item is used. Min-SAUD considers several factors that affect cache performance, namely, access probability, update frequency, Data size, retrieval delay, and cache validation cost. The paper employs stretch as the major performance metric since it accounts for the Data service time and, thus, is fair when items have different sizes. We prove that Min-SAUD achieves optimal stretch under some standard assumptions. Moreover, a series of simulation experiments have been conducted to thoroughly evaluate the performance of Min-SAUD under various system configurations. The simulation results show that, in most cases, the Min-SAUD replacement policy substantially outperforms two existing policies, namely, LRU and SAIU.
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an optimal cache replacement policy for wireless Data Dissemination under cache consistency
International Conference on Parallel Processing, 2001Co-Authors: Wangchien Lee, Dik Lun LeeAbstract:A good cache management method for mobile wireless environments has to handle problems associated with limited client resources and frequent client disconnections, in addition to standard problems found in wired environments, such as variable Data sizes and Data updates. In this paper we propose a gain-based cache replacement policy, Min-SAUD, for wireless Data Dissemination when cache consistency must be enforced before a cached item is used. Min-SAUD considers several factors that affect cache performance, namely access probability, update frequency, Data size, retrieval delay, and cache validation cost. Min-SAUD is optimal in terms of the stretch performance measure. Preliminary experimental results show that in most cases the Min-SAUD replacement policy substantially outperforms two existing policies, namely LRU and SAIU.
Guohong Cao - One of the best experts on this subject based on the ideXlab platform.
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user centric Data Dissemination in disruption tolerant networks
International Conference on Computer Communications, 2011Co-Authors: Wei Gao, Guohong CaoAbstract:Data Dissemination is useful for many applications of Disruption Tolerant Networks (DTNs). Current Data Dissemination schemes are generally network-centric ignoring user interests. In this paper, we propose a novel approach for user-centric Data Dissemination in DTNs, which considers satisfying user interests and maximizes the cost-effectiveness of Data Dissemination. Our approach is based on a social centrality metric, which considers the social contact patterns and interests of mobile users simultaneously, and thus ensures effective relay selection. The performance of our approach is evaluated from both theoretical and experimental perspectives. By formal analysis, we show the lower bound on the cost-effectiveness of Data Dissemination, and analytically investigate the tradeoff between the effectiveness of relay selection and the overhead of maintaining network information. By trace-driven simulations, we show that our approach achieves better cost-effectiveness than existing Data Dissemination schemes.
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Data pouring and buffering on the road a new Data Dissemination paradigm for vehicular ad hoc networks
IEEE Transactions on Vehicular Technology, 2007Co-Authors: Jing Zhao, Yang Zhang, Guohong CaoAbstract:Vehicular ad hoc networks (VANETs) have recently received considerable attention. To support VANET-based applications, it is important to disseminate Data from an information source (Data center) to many vehicles on the road. Although disseminating Data from a server to a large number of clients has been studied in the Database community and the network community, many unique characteristics of the VANET bring out new research challenges. In this paper, we propose a Data pouring (DP) and buffering paradigm to address the Data Dissemination problem in a VANET. In DP, Data are periodically broadcast to vehicles on the road. In DP with intersection buffering (DP-IB), Data poured from the source are buffered and rebroadcast at the intersections. We provide analytical models to explore the Dissemination capacity (DC) of the proposed schemes. The analytical models also provide guidelines on choosing the system parameters to maximize the DC under different delivery ratio requirements. Simulation results show that the proposed DP-IB scheme can significantly improve the Data delivery ratio and reduce network traffic.
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Data Dissemination with ring based index for wireless sensor networks
IEEE Transactions on Mobile Computing, 2007Co-Authors: Wensheng Zhang, Guohong Cao, T La PortaAbstract:In wireless sensor networks, sensor nodes are capable of not only measuring real world phenomena, but also storing, processing, and transferring these measurements. Many techniques have been proposed for disseminating sensing Data. However, most of them are not efficient in the scenarios where a huge amount of sensing Data are generated, but only a small portion of them are queried. In this paper, we first propose an index-based Data Dissemination scheme to address the problem. With this scheme, sensing Data are collected, processed, and stored at the nodes close to the detecting nodes, and the location information of these storing nodes is pushed to some index nodes, which act as the rendezvous points for sinks and sources. To address the issues of fault tolerance and load balance, we extend the scheme with an adaptive ring-based index (ARI) technique in which the index nodes for one event type form a ring surrounding the location which is determined by the event type, and the ring can be dynamically reconfigured. Considering that frequently updating or querying index nodes may cause high overhead, we also propose a lazy index updating (LIU) mechanism and a lazy index querying (LIQ) mechanism to reduce the overhead. Analysis and simulations are conducted to evaluate the performance of the proposed scheme. The results show that the proposed scheme outperforms the external storage-based scheme, the DCS scheme, and the local storage-based schemes with flood-response style. The results also show that using ARI can tolerate clustering failures and achieve load balance and using LIU (LIQ) can further improve the system performance. is pushed to some index nodes,
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Data Dissemination with ring based index for wireless sensor networks
International Conference on Network Protocols, 2003Co-Authors: Wensheng Zhang, Guohong Cao, T La PortaAbstract:In current sensor networks, sensor nodes are capable of not only measuring real world phenomena, but also storing, processing and transferring these measurements. Many Data Dissemination techniques have been proposed for sensor networks. However, these techniques may not work well in a large scale sensor network where a huge amount of sensing Data are generated, but only a small portion of them are queried. In this paper, we propose an index-based Data Dissemination scheme to address the problem. This scheme is based on the idea that sensing Data are collected, processed and stored at the nodes close to the detecting nodes, and the location information of these storing nodes is pushed to some index nodes, which act as the rendezvous points for sinks and sources. We further extend the scheme with an adaptive ring-based index (ARI) technique, in which the index nodes for one event type form a ring surrounding the location which is determined by the event type, and the ring can be dynamically reconfigured for fault tolerance and load balance. Analysis and simulations are conducted to evaluate the performance of the proposed index-based scheme. The results show that the index-based scheme outperforms the external storage-based scheme, the DCS scheme, and the local storage-based schemes with flood-response style. The results also show that using ARI can tolerate clustering failures and achieve load balance.
Lixia Zhang - One of the best experts on this subject based on the ideXlab platform.
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ttdd two tier Data Dissemination in large scale wireless sensor networks
Wireless Networks, 2005Co-Authors: Haiyun Luo, Jianping Cheng, Lixia ZhangAbstract:Sink mobility brings new challenges to Data Dissemination in large sensor networks. It suggests that information about each mobile sink's location be continuously propagated throughout the sensor field in order to keep all sensors informed of the direction of forwarding future Data reports. Unfortunately, frequent location updates from multiple sinks can lead to both excessive drain of sensors' limited battery supply and increased collisions in wireless transmissions. In this paper, we describe TTDD, a Two-Tier Data Dissemination approach that provides scalable and efficient Data delivery to multiple, mobile sinks. Each Data source in TTDD proactively constructs a grid structure, which enables mobile sinks to continuously receive Data on the move by flooding queries within a local cell only. TTDD's design exploits the fact that sensors are stationary and location-aware to construct and maintain the grid infrastructure with low overhead. We evaluate TTDD through both analysis and extensive simulations. Our results show that TTDD handles sink mobility effectively with performance comparable with that of stationary sinks.
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a two tier Data Dissemination model for large scale wireless sensor networks
ACM IEEE International Conference on Mobile Computing and Networking, 2002Co-Authors: Fan Ye, Haiyun Luo, Jerry Cheng, Songwu Lu, Lixia ZhangAbstract:Sink mobility brings new challenges to large-scale sensor networking. It suggests that information about each mobile sink's location be continuously propagated through the sensor field to keep all sensor nodes updated with the direction of forwarding future Data reports. Unfortunately frequent location updates from multiple sinks can lead to both excessive drain of sensors' limited battery power supply and increased collisions in wireless transmissions. In this paper we describe TTDD, a Two-Tier Data Dissemination approach that provides scalable and efficient Data delivery to multiple mobile sinks. Each Data source in TTDD proactively builds a grid structure which enables mobile sinks to continuously receive Data on the move by flooding queries within a local cell only. TTDD's design exploits the fact that sensor nodes are stationary and location-aware to construct and maintain the grid structures with low overhead. We have evaluated TTDD performance through both analysis and extensive simulation experiments. Our results show that TTDD handles multiple mobile sinks efficiently with performance comparable with that of stationary sinks.
Abderrahmane Lakas - One of the best experts on this subject based on the ideXlab platform.
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Efficient Data Dissemination for Urban Vehicular Environments
IEEE Transactions on Intelligent Transportation Systems, 2019Co-Authors: Moumena Chaqfeh, Hesham El-sayed, Abderrahmane LakasAbstract:Vehicular communication systems play an important role in the context of smart cities. Different applications are being proposed and evaluated to improve our daily driving in terms of safety and convenience. These applications require efficient Data Dissemination that guarantees full coverage with minimum overhead and delay. Existing Data Dissemination protocols often rely on extra communication to gather knowledge about the neighborhood and set the Dissemination criteria accordingly. This extra communication poses serious overhead issues that affect the scalability of Data Dissemination, which is an essential criterion under high density scenarios. In this paper, we propose and evaluate an Efficient multi-directional Data Dissemination Protocol (EDDP), which considers the requirements of an urban vehicular environment without requiring the extra communication overhead. We rely only on simple local Data to indicate the road condition for better Dissemination performance. In this paper, the design considerations of urban layout include message format, broadcast suppression mechanism, and delay control. The EDDP utilizes the properties of the received messages along with positioning information to make decisions on suppressing broadcasts, with the objective of improving coverage in different directions without unnecessary transmissions. Simulation results show that the EDDP can effectively disseminate traffic Data with a high Data delivery ratio and a minimized overhead.
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a survey on Data Dissemination in vehicular ad hoc networks
Vehicular Communications, 2014Co-Authors: Moumena Chaqfeh, Abderrahmane Lakas, Imad JawharAbstract:The rapid evolution of wireless communication capabilities and vehicular technology would allow traffic Data to be disseminated by traveling vehicles in the near future. Vehicular Ad hoc Networks (VANETs) are self-organizing networks that can significantly improve traffic safety and travel comfort, without requiring fixed infrastructure or centralized administration. However, Data Dissemination in VANET environment is a challenging task, mainly due to rapid changes in network topology and frequent fragmentation. In this paper, we survey existing Data Dissemination techniques and their performance modeling approaches in VANETs, along with optimization strategies under two basic models: the push model, and the pull model. In addition, we present major research challenges.
