A Power-Mitigating Scheme for Clusterheads in Wireless Sensor Networks

In a clustered Wireless Sensor Network (WSN), the nodes designated as clusterheads (CH) very likely will consume particularly large amount of power. This is because a CH is involved in everything taking place in the cluster, from in-cluster data collection, pre-processing, inter-cluster communication, to cluster administration. In this paper we investigate feasible ways of lessening the power consumption of CHs. The method we propose is to distribute the task of data collection to some non-CH nodes in the cluster. We introduce the notion of partaker nodes. The partakers\u27 role in a cluster is to assist the CH in the routine job of data collection. Instead of having CH alone collect data from all sensors in the cluster, a certain number of partaker nodes participate in data collection. They will help collect the raw data, and perform initial data aggregation/processing before transferring data to the CH.With partakers, a portion of power that would have been consumed by CHs is transferred to partakers. The power consumption of CHs can be reduced to various extents depending on the number, as well as the placement, of partakers

A rectilinear-monotone polygonal fault block model for fault-tolerant minimal routing in meshes

Abstract—We propose a new fault block model, Minimal-Connected-Component (MCC), for fault-tolerant adaptive routing in meshconnected multiprocessor systems. This model refines the widely used rectangular model by including fewer nonfaulty nodes in fault blocks. The positions of source/destination nodes relative to faulty nodes are taken into consideration when constructing fault blocks. The main idea behind it is that a node will be included in a fault block only if using it in a routing will definitely make the route nonminimal. The resulting fault blocks are of the rectilinear-monotone polygonal shapes. A sufficient and necessary condition is proposed for the existence of the minimal “Manhattan ” routes in the presence of such fault blocks. Based on the condition, an algorithm is proposed to determine the existence of Manhattan routes. Since MCC is designed to facilitate minimal route finding, if there exists no minimal route under MCC fault model, then there will be absolutely no minimal route whatsoever. We will also present two adaptive routing algorithms that construct a Manhattan route avoiding all fault blocks, should such routes exist. Index Terms—Adaptive routing, fault model, fault tolerance, interconnection network, mesh.

Diagnosability of Hypercubes and Enhanced Hypercubes under the Comparison Diagnosis Model

In [10], Sengupta and Dahbura discussed how to characterize a diagnosable system under the comparison diagnosis model proposed by Maeng and Malek and a polynomial algorithm was given to identify the faulty processors provided that the system\u27s diagnosability is known. However, for a general system, the determination of its diagnosability is not algorithmically easy. This paper proves that, for the important hypercube-structured multiprocessor systems (n-cubes), the diagnosability under the comparison model is n when n≥5. The paper also studies the diagnosability of enhanced hypercube, which is obtained by adding 2 n-1 more links to a regular hypercube of 2 n processors. It is shown that the augmented communication ability among processors also increases the system\u27s diagnosability under the comparison model. We will prove that the diagnosability is n+1 for an enhanced hypercube when n≥6

On Embedding Hamiltonian Cycles in Crossed Cubes

We study the embedding of Hamiltonian cycle in the Crossed Cube, a prominent variant of the classical hypercube, which is obtained by crossing some straight links of a hypercube, and has been attracting much research interest in literatures since its proposal. We will show that due to the loss of link-topology regularity, generating Hamiltonian cycles in a crossed cube is a more complicated procedure than in its original counterpart. The paper studies how the crossed links affect an otherwise succinct process to generate a host of well-structured Hamiltonian cycles traversing all nodes. The condition for generating these Hamiltonian cycles in a crossed cube is proposed. An algorithm is presented that works out a Hamiltonian cycle for a given link permutation. The useful properties revealed and algorithm proposed in this paper can find their way when system designers evaluate a candidate network\u27 s competence and suitability, balancing regularity and other performance criteria, in choosing an interconnection network

Constructing Optimal Subnetworks for the Crossed Cube Network

We present an algorithm that constructs subnetworks from an n-dimensional crossed cube, denoted CQ n, so that for any given κ, 2 ≤ κ ≤ n - 1, the algorithm can generate a κ-connected subnetwork that contains all 2 n original nodes of CQ n and preserves the symmetrical structure. The κ-connected subnetworks constructed are all optimal in the sense that they use the minimum number of links to maintain the required connectivity. Being able to construct κ-connected, all-node subnetworks are important in many applications, such as computing in the presence of faulty links, or diagnosing the system with a lower fault bound. Links that are not used by the induced subnetworks could be used in parallel by some other computing tasks, improving the overall resource utilization of the system

Cluster Subdivision Towards Power Savings for Randomly Deployed WSNs - An Analysis using 2-D Spatial Poisson Process

We propose to use a 2-dimensional (2-D for short) spatial Poisson process to model a WSN with randomly deployed sensors, and use the model to analyze a scheme that subdivides the clusters of a WSN to achieve an overall power savings. We assume no knowledge of how the sensors are spread in the sensing area, and hence need a statistical process to describe the distribution of all sensors. Assuming the 2-D spatial Poisson distribution, a comprehensive analysis is performed to estimate the power savings brought about by the proposed subdivision. Using hexagon as the shape of the cluster, the analysis shows that the subdivision scheme can yield significant savings in overall power consumption of sensors in the cluster

Hamiltonian Embedding in Crossed Cubes with Failed Links

The crossed cube is a prominent variant of the well known, highly regular-structured hypercube. In [24], it is shown that due to the loss of regularity in link topology, generating Hamiltonian cycles, even in a healthy crossed cube, is a more complicated procedure than in the hypercube, and fewer Hamiltonian cycles can be generated in the crossed cube. Because of the importance of fault-tolerance in interconnection networks, in this paper, we treat the problem of embedding Hamiltonian cycles into a crossed cube with failed links. We establish a relationship between the faulty link distribution and the crossed cube\u27s tolerability. A succinct algorithm is proposed to find a Hamiltonian cycle in a CQ n tolerating up to n-2 failed links