Distributed algorithm

About: Distributed algorithm is a research topic. Over the lifetime, 20416 publications have been published within this topic receiving 548109 citations.

A distributed algorithm for detecting resource deadlocks in distributed systems

Abstract: This paper presents a distributed algorithm to detect deadlocks in distributed data bases. Features of this paper are (1) a formal model of the problem is presented, (2) the correctness of the algorithm is proved, i.e. we show that all true deadlocks will be detected and deadlocks will not be reported falsely, (3) no assumptions are made other than that messages are received correctly and in order and (4) the algorithm is simple.

Proxy-based sensor deployment for mobile sensor networks

Abstract: To provide satisfactory coverage is very important in many sensor network applications such as military surveillance. In order to obtain the required coverage in harsh environments, mobile sensors are helpful since they can move to cover the area not reachable by static sensors. Previous work on mobile sensor deployment is based on a round by round process, where sensors move iteratively until the maximum coverage is reached. Although these solutions can deploy mobile sensors in a distributed way, the mobile sensors may move in a zig-zag way and waste a lot of energy compared to moving directly to the final location. To address this problem, we propose a proxy-based sensor deployment protocol. Instead of moving iteratively, sensors calculate their target locations based on a distributed iterative algorithm, move logically, and exchange new logical locations with their new logical neighbors. Actual movement only occurs when sensors determine their final locations. Simulation results show that the proposed protocol can significantly reduce the energy consumption compared to previous work, while maintaining similar coverage.

NOMAD: Non-locking, stOchastic Multi-machine algorithm for Asynchronous and Decentralized matrix completion

Abstract: We develop an efficient parallel distributed algorithm for matrix completion, named NOMAD (Non-locking, stOchastic Multi-machine algorithm for Asynchronous and Decentralized matrix completion). NOMAD is a decentralized algorithm with non-blocking communication between processors. One of the key features of NOMAD is that the ownership of a variable is asynchronously transferred between processors in a decentralized fashion. As a consequence it is a lock-free parallel algorithm. In spite of being an asynchronous algorithm, the variable updates of NOMAD are serializable, that is, there is an equivalent update ordering in a serial implementation. NOMAD outperforms synchronous algorithms which require explicit bulk synchronization after every iteration: our extensive empirical evaluation shows that not only does our algorithm perform well in distributed setting on commodity hardware, but also outperforms state-of-the-art algorithms on a HPC cluster both in multi-core and distributed memory settings.

A Self-Managed Distributed Channel Selection Algorithm for WLANs

Abstract: In this paper we consider the problem of a wireless LAN selecting a channel to minimise interference with other WLANs. We focus on interfering infrastructure-mode networks, where each access point (AP) or base station has a wired backhaul link. We introduce a new fully distributed and self-managed channel selection algorithm that does not require direct communication between APs nor explicit estimation of the network interference graph. The sole information required by the algorithm is feedback to each WLAN on the presence of interference on a chosen channel; such feedback is already commonly provided by WLAN protocols such as 802.11. We establish that convergence of the distributed algorithm is guaranteed provided that the channel selection problem is feasible. Extensive simulation results are presented that demonstrate rapid convergence under a wide range of network conditions and topologies. While the scope of the present paper is confined to infrastructure networks with static topology, the utility of the proposed algorithm in situations where the network topology is time-varying is briefly discussed.

Joint Resource Allocation for Parallel Multi-Radio Access in Heterogeneous Wireless Networks

Abstract: Heterogeneous wireless networks where several systems with different bands coexist for multimedia service are currently in service and will be widely adopted to support various traffic demand. Under heterogeneous networks, a mobile station can transmit over multiple and simultaneous radio access technologies (RATs) such as WLAN, HSPA, and WCDMA LTE. Also, cognitive radio for the efficient use of underutilized/unused frequency band is successfully implemented in some networks. In this letter, we address such operational issues as air interface and band selection for a mobile and power allocation to the chosen links. An optimal solution is sought and analyzed and a distributed joint allocation algorithm is proposed to maximize total system capacity. We investigate the benefit of multiple transmissions by multiple RATs over a single transmission by a single RAT at a time, which can be interpreted as network diversity. Numerical results validate the performance enhancement of our proposed algorithm.