共查询到20条相似文献,搜索用时 259 毫秒
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I. Saniee 《International Transactions in Operational Research》1996,3(2):187-195
Self-healing communication networks that allow re-routing of demands through switching processes at designated nodes are studied. It is shown how network utilization, demand throughput and reliability of such networks can be studied simultaneously to achieve an optimal design for all three. This is done through a max–min–max multi-commodity network flow formulation of the routing problem in which it is ensured that maximum network throughput is achieved with minimum loss of demands that are blocked due to single switching node failures. It is shown that a node-path linear programming approximation to the multi-commodity network flow formulation solves the problem for medium and large network sizes in moderate computational times. 相似文献
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《Journal of Parallel and Distributed Computing》2001,61(1):49-78
The performance of interconnection networks is significantly affected by router speed and routing adaptivity, which can be competing factors. To achieve a high-speed, true-fully-adaptive router design, this paper explores the exploitation of dynamic routing behavior identified as routing locality. When routing locality is exploited, it enables the internal crossbar of a router to be partitioned into smaller and faster units without sacrificing true-fully-adaptive routing capabilities. Extensive evaluation of partitioned crossbar designs which exploit routing locality shows that the increased adaptivity offered by deadlock recovery-based routing algorithms can be implemented in routers without sacrificing router speed. The partitioned crossbar designs reduce average message latency by up to 65% and increase maximum network throughput by up to 51%. 相似文献
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Most commercial network switches are designed to achieve good average throughput and delay needed for Internet traffic, whereas hard real-time applications demand a bounded delay. Our real-time switch combines clearance-time-optimal switching with clock-based scheduling on a crossbar switching fabric. We use real-time virtual machine tasks to serve both periodic and aperiodic traffic, which simplifies analysis and provides isolation from other system operations. We can then show that any feasible traffic will be switched in two clock periods. This delay bound is enabled by introducing one-shot traffic, which can be constructed at the cost of a fixed delay of one clock period. We carry out simulation to compare our switch with the popular iSLIP crossbar switch scheduler. Our switch has a larger schedulability region, a bounded lower end-to-end switching delay, and a shorter clearance time which is the time required to serve every packet in the system. 相似文献
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基于输入排队的高速交换调度算法研究 总被引:2,自引:0,他引:2
高速交换网络一般采用基于定长信元的交换结构,其性能决定于排队策略和信元调度算法.输入排队策略只有和一个有效的调度算法相结合,才能保证交换结构具有良好的吞吐率和时延等性能.主要阐述了基于VOQ的最大数量匹配算法,最大权重匹配算法,稳定结合算法,神经网络算法等输入排队调度算法,分别从技术特点,性能指标和实现复杂度等多个方面进行比较和分析.分析了分布式和集中式两大类调度算法的工作方式,并根据各类算法的特点提出,神经网络算法可以通过定义其优先级函数实现其余各类算法. 相似文献
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《Engineering Applications of Artificial Intelligence》2001,14(1):51-60
This paper presents a new approach based on the Hopfield model of artificial neural networks to solve the routing problem in a context of computer network design. The computer networks considered are packet switching networks, modeled as non-oriented graphs where nodes represent servers, hosts or switches, while bi-directional and symmetric arcs represent full duplex communication links. The proposed method is based on a network representation enabling to match each network configuration with a Hopfield neural network in order to find the best path between any node pair by minimizing an energy function. The results show that the time delay derived from flow assignment carried out by this approach is, in most cases, better than those determined using conventional routing heuristics. Therefore, this neural-network approach is suitable to be integrated into an overall topological design process of moderate-speed and high-speed networks subject to quality of service constraints as well as to changes in configuration and link costs. 相似文献
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It is shown that the throughput of buffered delta networks can be increased substantially by modifying the structure and operation of their crossbar switches, by using multiple links to connect the switches in the network, or by combining multiple delta networks in parallel. The variations tried in the structure of the crossbar switches are the size of the switch and the number of buffers in each switch, their capacity, and their position in the switch. Among the alternatives mentioned above, the use of two parallel links for each switch connection results in the highest throughput improvement. 相似文献
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拓扑结构和路由算法是影响多级交换网络性能的重要因素.在比较多种多级互连拓扑属性的基础上,提出将3D Torus结构应用于大规模交换网络设计.然后针对3D Torus交换网络中报文路由面临的两个关键问题:多路径负载均衡和报文保序,提出一种基于维序的多路径路由算法DMR(dimension-order—based multi—path routing).该算法可在保证报文顺序的同时在多条路径上平衡负载,提高交换网络吞吐率.最后通过模拟验证了算法的性能,并与维序路由和随机路由算法进行了比较.模拟结果表明,DMR算法的性能优于维序路由算法,能够达到随机路由算法性能水平,同时具有随机路由算法所不具备的报文保序特性. 相似文献
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Hopfiled神经网络方法已被广泛用于求解旅行商问题(TSP),但对于解中规模和大规模的TSP,存在效果不理想甚至难以求解的问题。为了较好地解决这个问题,该文提出一种K-Means聚类算法与Hopfield网络方法相结合求解TSP的新方法,先应用聚类算法对所给城市进行聚类以获得几组规模较小的城市,然后对每一组城市应用Hopfield网络方法进行求解,最后把求解后的每组城市连接起来。计算机仿真结果表明,该方法可以获得最优有效解,并且解的质量明显提高,对求解中大规模的TSP比较有效。 相似文献
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延迟离散Hopfield型神经网络异步收敛性 总被引:6,自引:1,他引:5
离散Hopfield型神经网络的一个重要性质是异步运动方式下总能收敛到稳定态。同步运行方式下总能收敛到周期不超过2的极限环,它是该模型可以用于联想记忆设计,组合设计计算的理论基础,文中给出了延迟离散Hopfield型网络的收敛性定理,在异步运动方式下,证明了对称连接权阵的收敛性定理,推广了已有的离散Hopfield型网络的收敛性结果,给出了能量函数极大值点与延迟离散Hopfield型网络的稳定态的 相似文献
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Giaccone P. Leonardi E. Shah D. 《Parallel and Distributed Systems, IEEE Transactions on》2007,18(2):251-263
Most of the current communication networks, including the Internet, are packet switched networks. One of the main reasons behind the success of packet switched networks is the possibility of performance gain due to multiplexing of network bandwidth. The multiplexing gain crucially depends on the size of the buffers available at the nodes of the network to store packets at the congested links. However, most of the previous work assumes the availability of infinite buffer-size. In this paper, we study the effect of finite buffer-size on the performance of networks of interacting queues. In particular, we study the throughput of flow-controlled loss-less networks with finite buffers. The main result of this paper is the characterization of a dynamic scheduling policy that achieves the maximal throughput with a minimal finite buffer at the internal nodes of the network under memory-less (e.g., Bernoulli IID) exogenous arrival process. However, this ideal performance policy is rather complex and, hence, difficult to implement. This leads us to the design of a simpler and possibly implementable policy. We obtain a natural trade-off between throughput and buffer-size for such implementable policy. Finally, we apply our results to packet switches with buffered crossbar architecture 相似文献
17.
Manu Pratap Singh Rinku Sharma Dixit 《Engineering Applications of Artificial Intelligence》2013,26(10):2383-2396
In this paper we are studying the optimization of Stochastic Hopfield neural network and the hybrid SOM–Hopfield neural network for the storage and recalling of fingerprint images. The feature extraction of these images has been performed using FFT, DWT and SOM. The feature vectors are stored in the Hopfield network with Hebbian learning and modified Pseudoinverse learning rules. The study explores the tolerance of Hopfield neural networks for reducing the effect of spurious minima in the recalling process by employing the Simulated annealing process. It is observed from the simulations that the capabilities of the Hopfield network can be sufficiently enhanced by making modifications in the feature extraction of the input data. DWT and SOM together can be used to significantly enhance the recall efficiency. The probability of error in recall in the form of spurious minima is minimized by adopting simulated annealing process in the pattern recalling process. 相似文献
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S Matsuda 《Neural Networks, IEEE Transactions on》1998,9(6):1319-1330
An "optimal" Hopfield network is presented for combinatorial optimization problems with linear cost function. It is proved that a vertex of the network state hypercube is asymptotically stable if and only if it is an optimal solution to the problem. That is, one can always obtain an optimal solution whenever the network converges to a vertex. In this sense, this network can be called the "optimal" Hopfield network. It is also shown through simulations of assignment problems that this network obtains optimal or nearly optimal solutions more frequently than other familiar Hopfield networks. 相似文献
19.
Der-Fu Tao Author Vitae Liang-Teh Lee Author Vitae Chen-Feng Wu Author Vitae 《Computers & Electrical Engineering》2008,34(3):222-231
In recent years, network applications and hardware technology have been developed in impressive speed. That is, a large-scale network switching system is needed to satisfy all demand among network service providers and population, such as data, voice, image, video on demand, videoconferencing, telecommunications, remote control and teaching, etc. A general large-scale network switching system cannot fulfill various application needs, such as the correctness of data transmission and the capacity of extension for input/output port of switching system. In this paper, we propose a nested ring-based architecture to build a very large-scale network switching system. In order to satisfy the various network application needs, a nested ring-based architecture is designed as a switching element. It can make input data exchange fast to the destined output port, and input/output port of switching system can easily be extended up to 100 ports or 1000 ports to construct a very large-scale network switching system. The simulation results show that a better performance can be achieved in data transmission, delay, throughput and extensibility for the proposed system. 相似文献
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论文对宽带网的动态路由分配问题进行了讨论,提出了一种基于Hopfield神经网络的算法,它具有能高速实时实现的优点及对网络状态和拓扑结构变化的适应性。计算机模拟表明此算法的有效性。 相似文献