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在数据网格应用中,数据会由于性能和可用性等原因进行复制.如何使数据复本合理分布以降低通信开销是数据网格系统需要解决的重要问题.本文针对一种简化的数据网格环境,考虑存储资源代理对数据的访问频率和代理间的网络性能,提出一种填空式数据副本分配算法(CDRDA).通过该算法得到的数据副本分配,构成多级虚拟存储架构.数据副本根据被存储资源代理访问的频率分布在访问开销小的节点上,从而使系统的整体访问效率达到近似最优. 相似文献
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设计无人机自组网媒体接入控制(Medium Access Control,MAC)协议时,需要考虑其控制开销和数据传输的可靠性。鉴于此,结合现有无线自组网多跳时分多址接入(Time Division Multiple Access,TDMA)协议和无人机自组网特点,提出了一种高效可靠的无人机自组网多跳TDMA协议。首先采用高效负载均衡的时隙请求信息上传机制,选择一个负载较小的节点转发节点时隙请求信息;然后根据相互通信的父节点删除重复节点的时隙请求信息,减少相同节点的时隙请求信息转发次数;最后通过实时更新节点时隙请求信息机制,提高节点时隙请求信息传输的可靠性。仿真结果表明,该协议在数据传输成功率、平均时延、控制开销方面优于现有协议,可较好地应用在无人机自组网中。 相似文献
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《现代电子技术》2019,(10)
针对无线自组网节点的移动导致多播可靠性降低、开销和时延增加的问题,提出基于邻居覆盖信息的多播方案。该方案通过少量的Hello报文收集一跳内的邻居信息,并据此实时计算节点的密度系数、邻居节点未覆盖率等参数,利用所获参数动态调整节点的多播数据转发时延与转发概率。为进一步降低时延,提出一种基于节点移动速度的数据分发方案,它允许部分快速移动节点采用更高的概率转发多播数据。将其扩展至多播方案中,形成基于邻居覆盖信息和节点移动速度的多播方案。NS2的仿真结果表明,与现有方案相比,该方案将分组投递率提高27%,控制开销减少33.2%,并将端到端平均时延降低45%。 相似文献
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移动自组网中大多采用冲突避免协议,广播时存在大量的冗余数据及信道冲突,在复杂的信道环境下会降低系统的通信效率。结合协同通信与动态时隙分配技术,提出了一种基于协同通信的移动自组网广播方案。该方案分成竞争、控制报文和数据传输3个阶段。竞争阶段利用基于载波侦听多址访问(Carrier Sense Multiple Access,CSMA)的广播网络洪泛少量竞争报文,分配广播权限;控制报文阶段结合协同通信,利用时隙分配算法完成节点的时隙分配;数据传输阶段,利用协同通信结合时分多址(Time Division Multiple Access,TDMA)动态时隙分配算法,使得节点能够充分利用信道资源进行数据发送,避免节点间的相互竞争,提高数据传输效率。 相似文献
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在移动P2P网络中一个基本应用问题是访问分布式空间数据库中的数据对象,同时节省电量.文中提出了在移动P2P网络中能量有效连续查询处理(Energy Efficient Continuous Query Processing,EECQP)算法,包括范围查询和k个最近邻居节点查询(k-nearest-neighbor queries, k-NN).EECQP算法能够提供移动用户找到一个有质量保证的连续查询结果.EECQP算法主要的想法是允许用户与节点合作,持续保存查询结果,而不是总是从头开始处理查询,从而减少通信开销.实验结果表明所提出的EECQP算法对于范围查询和k个最近邻居节点查询在通信开销和QoS保证是能量有效和可扩展的. 相似文献
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802.11移动自组网由于其固有的动态拓扑、分布式协作等特点,路由协议普遍采用多播方式以提高无线链接的传输效率,由此带来的拥塞使得移动自组网中多播拥塞控制至关重要。针对移动自组网中节点固有的随机特性,基于802.11 DCF协议,该文提出一种精确描述节点数据产生、排队、发送动态过程的拟生灭模型,并通过矩阵几何方法对其进行稳态分析,得出节点速率阈值方程组,并用OPNET进行了仿真实验,仿真结果与理论值拟合较好,为移动自组网中的拥塞控制提供了一个量化的指标。 相似文献
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An opportunistic network (OPPNET) consists of diverse mobile nodes with various mobility patterns. Numerous mobility patterns and the resource constraints of mobile nodes lead to network partitioning that result in system performance degradation including low data accessibility. In a traditional mobile ad hoc network (MANET) which is similar to an OPPNET, replica allocation schemes have been proposed to increase data accessibility. Although the schemes are efficient in a MANET, they may not be directly applicable to an OPPNET because the schemes are based on a grouping of mobile nodes. It is very difficult to build groups based on network topology in an OPPNET because a node in an OPPNET does not keep its network topology information. In this paper, we propose a novel replica allocation scheme for an opportunistic network called the Snooping-based Fully Distributed replica allocation scheme. The proposed scheme allocates replicas in a fully distributed manner without grouping to reduce the communication cost, and fetches allocated replicas utilizing a novel candidate list concept to achieve high data accessibility. In the proposed scheme, a node can fetch replicas opportunistically based on the candidate list. Consequently, the proposed replica allocation scheme achieves high data accessibility while reducing the communication cost significantly. Extensive simulation results demonstrate that the proposed scheme reduces the communication cost and improves data accessibility over traditional schemes. 相似文献
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To reduce fetching cost from a remote source,it is natural to cache information near the users who may access the information later.However,with development of 5 G ultra-dense cellular networks andmobile edge computing(MEC),a reasonable selection among edge servers for content delivery becomes a problem when the mobile edge obtaining sufficient replica servers.In order to minimize the total cost accounting for both caching and fetching process,we study the optimal resource allocation for the content replica servers’ deployment.We decompose the total cost as the superposition of cost in several coverages.Particularly,we consider the criterion for determining the coverage of a replica server and formulate the coverage as a tradeoff between caching cost and fetching cost.According to the criterion,a coverage isolation(CI) algorithm is proposed to solve the deployment problem.The numerical results show that the proposed CI algorithm can reduce the cost and obtain a higher tolerance for different centrality indices. 相似文献
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Many data replication techniques have been proposed to minimize performance degradation caused by network partitioning in a mobile ad-hoc network. Most of them assume that all mobile nodes collaborate fully in terms of sharing their memory space. However, in reality, some nodes may selfishly decide to only cooperate partially, or not at all, with other nodes. Recently, a new approach to selfish replica allocation has been proposed to handle node selfishness. However, there is still much room for improvement. We empirically observe that the previous selfish replica allocation strategy suffers from long query delay and poor data accessibility, because it utilizes only non-selfish nodes that may be faraway nodes. In this paper, we propose a novel replica allocation strategy in the presence of selfish nodes, that takes into account both selfish behavior and node distance. Moreover, through a novel node leveling technique, we utilize the memory space of all connected nodes, including selfish nodes. The conducted simulations demonstrate that the proposed strategy outperforms existing replica allocation techniques in terms of data accessibility, query delay, and communication cost. 相似文献
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A mobile device in a MANET must be assigned a free IP address before it may participate in unicast communication. This is a fundamental and difficult problem in the practical use of any MANET. Several solutions have been proposed. However, these approaches have different drawbacks. A new IP address allocation algorithm, namely prophet address allocation, is proposed in the paper. The proposed scheme may be applied to large scale MANETs with low complexity, low communication overhead, even address distribution, and low latency. Both theoretical analysis and simulation experiments are conducted to demonstrate the superiority of the proposed algorithm over other known algorithms. Moreover, the proposed prophet allocation is able to solve the problem of network partition and merger efficiently. 相似文献
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In recent years, with the rapid development of data intensive applications, data replication has become an enabling technology for the data grid to improve data availability, and reduce file transfer time and bandwidth consumption. The placement of replicas has been proven to be the most difficult problem that must be solved to realize the process of data replication. This paper addresses the quality of service (QoS) aware replica placement problem in data grid, and proposes a dynamic programming based replica placement algorithm that not only has a QoS requirement guarantee, but also can minimize the overall replication cost, including storage cost and communication cost. By simulation, experiments show that the replica placement algorithm outperforms an existing popular replica placement technique in data grid. 相似文献
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Jaganathan Logeshwaran Nallasamy Shanmugasundaram Jaime Lloret 《International Journal of Communication Systems》2023,36(13):e5524
In general, there are several many devices that can overload the network and reduce performance. Devices can minimize interference and optimize bandwidth usage by using directional antennas and by avoiding overlapping communication ranges. In addition, devices need to carefully manage their use of resources, such as bandwidth and energy. Bandwidth is limited in wireless personal area networks (WPANs), so devices need to carefully select which data to send and receive. In this paper, an intelligent performance analysis of energy-efficient resource optimization model has been proposed for device-to-device (D2D) communication in fifth-generation (5G) WPAN. The proposed energy-efficient resource allocation in D2D communication is important because it helps reduce energy consumption and extend the lifespan of devices that are communicating with each other. By allocating resources in an efficient manner, communication between two devices can be optimized for maximum efficiency. This helps reduce the amount of energy needed to power the communication, as well as the amount of energy needed to power the device that is communicating with another device. Additionally, efficient resource allocation helps reduce the overall cost of communication, as the use of fewer resources results in a lower overall cost. The proposed efficient resource allocation helps reduce the environmental impact of communication, as less energy is used for communication. The proposed energy-efficient resource allocation model (EERAM) has reached 92.97% of energy allocation, 88.72% of power allocation, 87.79% of bandwidth allocation, 87.93% of spectrum allocation, 88.43% of channel allocation, 25.47% of end-to-end delay, 94.33% of network data speed, and 90.99% of network throughput. 相似文献
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Dynamic address allocation is an essential part in effective configuration and maintenance of a mobile ad-hoc network (MANET).
In this paper, we present a new distributed dynamic address allocation protocol minimizing address allocation latency and
communication overhead. Through analytic evaluation and experimental measurements, we show that scalability and faster recovery
from failures can be achieved by dynamic address allocation. The dynamic address assignment protocol presented here requires
a low memory footprint while supporting unicast, broadcast and multicast communication. A performance analysis of the proposed
address allocation protocol is given in terms of address allocation latency and communication overhead. Node and Network mobility
is addressed from the point of dynamic address management. The dynamic address allocation protocol is implemented on a TinyOS
platform over a cluster tree network. 相似文献
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Shouzhen Gu Qingfeng Zhuge Juan Yi Jingtong Hu Edwin H.-M. Sha 《Journal of Signal Processing Systems》2016,84(1):151-162
As the advance of memory technologies, multiple types of memories such as different kinds of non-volatile memory (NVM), SRAM, DRAM, etc. provide a flexible configuration considering performance, energy and cost. For improving the performance of systems with multiple types of memories, data allocation is one of the most important tasks. The previous studies on data allocation problem assume the worst (fixed) case of data-access frequencies. However, the data allocation produced by employing worst case usually leads to an inferior performance for most of time. In this paper, we model this problem by probabilities and design efficient algorithms that can give optimal-cost data allocation with a guaranteed probability. We propose DAGP algorithm produces a set of feasible data allocation solutions which generates the minimum access time or cost guaranteed by a given probability. We also propose a polynomial-time algorithm, MCS algorithm, to solve this problem. The experiments show that our technique can significantly reduce the access cost compared with the technique considering worst case scenario. For example, comparing with the optimal result generated by employing the worst cases, DAGP can reduce memory access cost by 9.92 % on average when guaranteed probability is set to be 0.9. Moreover, for 90 percents of cases, memory access time is reduced by 12.47 % on average. Comparing with greedy algorithm, DAGP and MCS can reduce memory access cost by 78.92 % and 44.69 % on average when guaranteed probability is set to be 0.9. 相似文献
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Cross-Layer Design for Data Accessibility in Mobile Ad Hoc Networks 总被引:14,自引:0,他引:14
Mobile ad hoc networks (MANET) are becoming an integral part of the ubiquitouscomputing and communication environment, providing new infrastructure formultimedia applications such as video phone, multimedia-on-demand, and others.In order to access multimedia information in MANET, Quality of Service (QoS)needs to be considered, such as high success rate to access multimedia data,bounded end-to-end delay, and others. In this paper, we present a dataaccessibility service for a group of mobile users to access desired data withhigh success rate. This accessibility service is only possible if we utilizeadvanced data advertising, lookup and replication services, as well as a novelpredictive location-based QoS routing protocol in an integrated fashion. Usingcross-layer design, we illustrate how the QoS routing protocol assists dataadvertising, lookup and replication services to achieve high data accesssuccess rate. Simulation results have shown that our design is successful ina dynamic MANET. 相似文献