Parity conditions in homotopic knock-knee routing

We examine the impact ofevenness (all cuts having even free capacity) andlocal evenness (cuts that separate a single vertex having even free capacity) on homotopic knock-knee routing. Kaufmann and Mehlhorn have presented a linear-time algorithm for routing even instances. We show that routing locally even instances is NP-hard. If we are permitted to move modules slightly, however, then we can efficiently route any locally even instance in which the free capacity of every cut is nonnegative. This fact implies that locally even instances can be one-dimensionally compacted in polynomial time. But when the assumption of local evenness is dropped, routing again becomes NP-hard, whether or not modules may move.This work was supported in part by the Deutsche Forschungsgemeinschaft, Sonderforschungsbereich 124, Teilprojekt B2 (VLSI Entwurf und Parallelität), and in part by DIMACS (Center for Discrete Mathematics and Theoretical Computer Science), a National Science Foundation Science and Technology Center, Grant NSF-STC88-09648. Miller Maley was also supported by a Mathematical Sciences Postdoctoral Research Fellowship from the National Science Foundation, Grant DMS-8705835.     

LSI channel routing algorithms

A new method is proposed and an algorithm is developed for two-wire channel routing in a two-layer board, with horizontal interconnections made in one layer and vertical interconnections in the other layer.Translated from Kibernetika, No. 3, pp. 32–35, May–June, 1991.     

认知无线电网络组播路由算法和协议综述

认知无线电网络（CRN）在实现更好的无线带宽利用率和提高无线应用质量方面发挥着至关重要的作用。由于认知用户可用频谱机会的动态特性,认知无线电网络中的组播是一个具有挑战性的问题。研究者们已经提出了多种在认知无线电网络中进行有效组播的方案,包括基于优化理论、网络编码、机器学习、博弈论的方案等。总结了解决组播问题有效的算法和技术,并对已有的无线电网络中的组播协议进行了全面的综述,最后给出了未来的研究方向。     

片上网络路由算法的研究

路由算法作为片上网络研究的一项关键技术,负责将分组正确无误地发送到目的节点.片上网络路由算法可分为无关路由算法和自适应路由算法两种.无关路由算法简单易实现,但具有一定的盲目性,自适应路由算法能够灵活地选择路由路径,却需要复杂的控制逻辑和硬件电路.对目前已经出现的几种路由算法进行了分析、对比,并从所适用拓扑、是否防止死锁等方面对算法进行了评价,并提出了片上网络路由算法的研究方向.     

Load-aware routing in mesh networks: Models, algorithms and experimentation

In this paper we consider wireless mesh networks (WMNs) used to share the Internet connectivity of sparsely deployed fixed lines with heterogeneous capacity, ranging from ISP-owned high-speed links to subscriber-owned low-speed connections. If traffic is routed in the mesh without considering the load distribution and the bandwidth of Internet connections, some gateways may rapidly get overloaded because they are selected by too many mesh nodes. This may cause a significant reduction of the overall network capacity. To address this issue, in this paper we first develop a queuing network model that predicts the residual capacity of network paths, and identifies network bottlenecks. By taking advantage of this model, we design a novel Load-Aware Route Selection algorithm, named LARS, which improves the network capacity by allocating network paths to upstream Internet flows so as to ensure a more balanced utilization of wireless network resources and gateways’ Internet connections. Using simulations and a prototype implementation, we show that the LARS scheme significantly outperforms the shortest-path first routing protocol using a contention-aware routing metric, providing up to 240% throughput improvement in some network scenarios.     

Parallel algorithms for routing in nonblocking networks

We construct nonblocking networks that are efficient not only as regards their cost and delay, but also as regards the time and space required to control them. In this paper we present the first simultaneous weakly optimal solutions for the explicit construction of nonblocking networks, the design of algorithms and data-structures. Weakly optimal is in the sense that all measures of complexity (size and depth of the network, time for the algorithm, space for the data-structure, and number of processor-time product) are within one or more logarithmic factors of their smallest possible values. In fact, we construct a scheme in which networks withn inputs andn outputs have sizeO(n(logn)²) and depthO(logn), and we present deterministic and randomized on-line parallel algorithms to establish and abolish routes dynamically in these networks. In particular, the deterministic algorithm usesO((logn)⁵) steps to process any number of transactions in parallel (with one processor per transaction), maintaining a data structure that useO(n(logn)²) words.     

一类层次双环网络的构造及其路由算法

高效互联网络的拓扑结构一直是人们关注的热点问题。提出了一类层次双环互联网络HDRN（k）,给出了HDRN（k）网络的构造方法,研究了它的性质,并且通过与相关网络的比较,证实了HDRN（k）具有好的连接性、短的直径以及简单的拓扑结构,是一种实用的互联网络。另外,讨论了HDRN（k）网络的路由性质,设计了点点路由和Broadcast路由算法,证明了这两种路由算法的通信效率与层次环网络上对应算法的通信效率相比均有明显的提高。综上所述,HDRN（k）是一种具有良好拓扑性质的新型互联网络。     

Channel routing in a Diagonal Overlap model

In this paper we study the channel routing problem (CRP) in a new routing model, called Overlap Diagonal Model (ODM), where the grid consists of right and left tracks displayed at +45° and ?45°. For the unrestrictedoverlap, we present an algorithm which achieves \(w = \left[ {\frac{d}{2}} \right] + 1\) , while for the restricted-overlap, we havew=d+1, whered is the channel density,w is the channel width.     

Optimal algorithms for adjacent side routing

We consider the switchbox routing problem of two-terminal nets in the case when all thek nets lie on two adjacent sides of the rectangle. Our routing model is the standard two-layer model. We develop an optimal algorithm that routes all the nets whenever a routing exists. The routing obtained uses the fewest possible number of vias. A more general version of this problem (adjacent staircase) is also optimally solved.This research was supported in part by NSA Contract No. MDA-904-85H-0015, NSF Grant No. DCR-86-00378, and by NSF Engineering Research Centers Program NSFD CDR 88003012.     

Work-efficient routing algorithms for rearrangeable symmetricalnetworks

The work performed by a parallel algorithm is the product of its running time and the number of processors it requires. This paper presents work-efficient (or cost-optimal) routing algorithms to determine the switch settings for realizing permutations on rearrangeable symmetrical networks such as Benes and the reduced Ω _NΩ_N^-1. These networks have 2n-1 stages with N=2ⁿ inputs/outputs, each stage consisting of N/2 crossbar switches of size (2×2). Previously known parallel routing algorithms for a rearrangeable network with N inputs determine the states of all switches recursively in O(n) iterations using N processors. Each iteration determines the switch settings of at most two stages of the network and requires at least O(n) time on a computer of N processors, regardless of the type of its interconnection network. Hence, the work of any previously known parallel routing algorithm equals at least O(Nn²) for setting up all the switches of a rearrangeable network. The new routing algorithms run on a computer of p processors, 1⩽p⩽N/n, and perform work O(Nn). Moreover, because the range of p is large, the new routing algorithms do not have to be changed in case some processors become faulty     

Data aggregation and routing in Wireless Sensor Networks: Optimal and heuristic algorithms

A fundamental challenge in the design of Wireless Sensor Networks (WSNs) is to maximize their lifetimes especially when they have a limited and non-replenishable energy supply. To extend the network lifetime, power management and energy-efficient communication techniques at all layers become necessary. In this paper, we present solutions for the data gathering and routing problem with in-network aggregation in WSNs. Our objective is to maximize the network lifetime by utilizing data aggregation and in-network processing techniques. We particularly focus on the joint problem of optimal data routing with data aggregation en route such that the above mentioned objective is achieved. We present Grid-based Routing and Aggregator Selection Scheme (GRASS), a scheme for WSNs that can achieve low energy dissipation and low latency without sacrificing quality. GRASS embodies optimal (exact) as well as heuristic approaches to find the minimum number of aggregation points while routing data to the Base-Station (BS) such that the network lifetime is maximized. Our results show that, when compared to other schemes, GRASS improves system lifetime with acceptable levels of latency in data aggregation and without sacrificing data quality.     

Ad Hoc多径路由算法

针对Ad Hoc网络,在分析AODV单径路由协议的基础上,结合路径稳定的衡量——熵,利用路由请求包唯一性和标志位信息,提出一种开销最小节点不相交的多径路由算法ENDMAODV.该算法能够发现多条节点不相交路由路径,并从中选取2条稳定性较好的路径.仿真结果表明,ENDMAODV协议在路径重构次数、分组投送率、平均控制开销和端到端时延方面表现出较优性能,为自组织网络多径路由算法的设计提供了新思路.     

Performance comparison of routing algorithms in wormhole-switched networks

This paper presents, building on the analytical models developed in [A. Shahrabi, M. Ould-Khoua, L. Mackenzie, Performance modelling of broadcast communication in multicomputer networks, International Journal of Parallel, Emergent, and Distributed Systems 20 (1) (2005); A. Shahrabi, M. Ould-Khoua, On the communication latency of wormhole routed interconnection networks, International Journal of Simulation 4 (5–6) (2003) 32–43; A. Shahrabi, L. Mackenzie, M. Ould-Khoua, Modelling of Adaptive Wormhole-Routed Hypercubes in the Presence of Broadcast Traffic, in: N.J. Dimopoulos, K.F. Li (Eds.), Chapter 10 in High Performance Computing Systems And Applications, Kluwer Academic Publishers, Boston, 2002; A. Shahrabi, M. Ould-Khoua, L. Mackenzie, An Analytical Model of Wormhole-Routed Hypercubes under Broadcast Traffic, Performance Evaluation 53 (1) (2003) 23–42; A. Shahrabi, M. Ould-Khoua, L. Mackenzie, Latency of double-tree broadcast in wormhole-routed hypercubes, in: Proceedings of International Conference on Parallel Processing (ICPP’01), IEEE Computer Society, 2001, pp. 401–408] a comparative performance study of adaptive and deterministic routing algorithms in wormhole-switched interconnection networks carrying a broadcast traffic component and investigates the performance vicissitudes of them under a variety of network operating conditions. In contrast to previous works, which have reported superiority of adaptive over deterministic routing especially in high-dimensional networks such as hypercubes, our results show that adaptivity does not necessarily improve network performance even for high-dimensional networks and its superiority starts to deteriorate as the broadcast fraction of generated traffic increases.     

Robust algorithms for packet routing in a mesh

This paper considers the problem of permutation packet routing on a n×n mesh-connected array of processors. Each node in the array is assumed to be independently faulty with a probability bounded above by a valuep. This paper gives a routing algorithm which, ifp 0.29, will with very high probability route every packet that can be routed inO(n logn) steps with queue lengths that areO(log² n). Extensions to higher-dimensional meshes are given.     

Cyclic routing algorithms in graphs: Performance analysis and applications to robot scheduling

In this paper we revisit and extend the algorithm for the cyclic project scheduling problem which was originally proposed by Romanovskii (1967). While the algorithm has been derived for fixed numerical data, we show how it can be extended to handle the problems with interval data. We also propose a new algorithm for the cyclic scheduling problem with interval data that extends the parametric method developed by Megiddo (1979) and runs in strongly polynomial time.     

Zone selection strategy in Geocast routing algorithms in VANET: a review

The Journal of Supercomputing - Vehicle Ad hoc Network (VANET) is emerging as a desirable technology to make a revolution in transportation system. Due to the high and predictable mobility of...     

Group multicast routing problem: A genetic algorithms based approach

To save network resources, multicast transmissions are more and more adopted by the operators when the same content has to reach several destinations in parallel, such as in IPTV services, radio broadcast and video-clip streaming. Though, with respect to unicast transmissions, multicast sessions make the routing problem more complex with huge sets of trees to be evaluated. Additionally, since in the real world several multicast sessions occur simultaneously, the suitable trees for more sessions have to be found concurrently. This problem is addressed in this paper, which proposes the use of the genetic algorithms (GA) to reduce the number of solutions to be evaluated. Firstly, a heuristic procedure is employed to generate a set of possible trees for each session in isolation; secondly, the GA are applied to find the appropriate combination of the trees to comply with the bandwidth needs of the group of multicast sessions simultaneously. The goodness of each solution is assessed by means of an expression that weights both network bandwidth allocation and one-way delay. Some key parameters are also introduced that allow the operator to find the desired balance between quality of service and network resource utilization. Experimental results are provided to show the performance of the proposed algorithm compared with alternative solutions in terms of bandwidth utilization and transmission delay and to illustrate the influence of the selection and crossover procedures configuration.     

The production routing problem: A review of formulations and solution algorithms

The production routing problem (PRP) combines the lot-sizing problem and the vehicle routing problem, two classical problems that have been extensively studied for more than half a century. The PRP is solved in an attempt to jointly optimize production, inventory, distribution and routing decisions and is thus a generalization of the inventory routing problem (IRP). Although the PRP has a complicated structure, there has been a growing interest in this problem during the past decade in both academia and industry. This article provides a comprehensive review of various solution techniques that have been proposed to solve the PRP. We attempt to provide an in-depth summary and discussion of different formulation schemes and of algorithmic and computational issues. Finally, we point out interesting research directions for further developments in production routing.     

移动社会网络中社会性路由算法研究

在无法部署Sink的无线传感器网络中, 数据采集者(即:能够收集数据的人或移动设备)在网络的任意位置收集数据, 即泛在数据收集。网络区域中的节点数量庞大, 能量有限, 如何能有效地采集到全部节点的数据是一个难点。提出一个网络生命周期最大化的泛在数据收集协议MULAC。MULAC以用户所在当前位置为圆心, 半径为r的区域内选择一个节点v。以v为根构造一棵最大化生命周期树T。网络中的节点可以通过T传送数据给v, 数据采集者可以通过v接收到网络中的全部数据。当数据采集者移动到其他位置, T将根据用户新的位置改变根节点, 并且以最小的能量耗费调整树结构, 从而延长全网的寿命。在收集数据过程中保证无线传感器网络生命周期最大化是一个NP完全问题, MULAC能够近似最优的解决此问题。仿真实验和理论分析表明, MULAC能有效延长网络生命周期。