Mobile Adhoc and Sensor Systems 

About: Mobile Adhoc and Sensor Systems is an academic conference. The conference publishes majorly in the area(s): Wireless sensor network & Wireless ad hoc network. Over the lifetime, 6499 publications have been published by the conference receiving 39987 citations.

An energy-efficient unequal clustering mechanism for wireless sensor networks

Abstract: Clustering provides an effective way for prolonging the lifetime of a wireless sensor network. Current clustering algorithms usually utilize two techniques, selecting cluster heads with more residual energy and rotating cluster heads periodically, to distribute the energy consumption among nodes in each cluster and extend the network lifetime. However, they rarely consider the hot spots problem in multihop wireless sensor networks. When cluster heads cooperate with each other to forward their data to the base station, the cluster heads closer to the base station are burdened with heavy relay traffic and tend to die early, leaving areas of the network uncovered and causing network partition. To address the problem, we propose an energy-efficient unequal clustering (EEUC) mechanism for periodical data gathering in wireless sensor networks. It partitions the nodes into clusters of unequal size, and clusters closer to the base station have smaller sizes than those farther away from the base station. Thus cluster heads closer to the base station can preserve some energy for the inter-cluster data forwarding. We also propose an energy-aware multihop routing protocol for the inter-cluster communication. Simulation results show that our unequal clustering mechanism balances the energy consumption well among all sensor nodes and achieves an obvious improvement on the network lifetime

Localization of wireless sensor networks with a mobile beacon

Abstract: Wireless sensor networks have the potential to become the pervasive sensing (and actuating) technology of the future For many applications, a large number of inexpensive sensors is preferable to a few expensive ones The large number of sensors in a sensor network and most application scenarios preclude hand placement of the sensors Determining the physical location of the sensors after they have been deployed is known as the problem of localization We present a localization technique based on a single mobile beacon aware of its position (eg by being equipped with a GPS receiver) Sensor nodes receiving beacon packets infer proximity constraints to the mobile beacon and use them to construct and maintain position estimates The proposed scheme is radio-frequency based, and thus no extra hardware is necessary The accuracy (on the order of a few meters in most cases) is sufficient for most applications An implementation is used to evaluate the performance of the proposed approach

Backup and storage management in distributed heterogeneous environments

Abstract: Powerful but nevertheless easy-to-operate systems for backing up and reconstructing data from clients are necessary in a distributed heterogeneous environment. The concept of the Siemens Nixdorf Informationssysteme (SNI) AG is based on a client/server model. It runs under the control of a SINIX server and includes backup clients for various Unix systems, PCs such as those with MS-DOS/Windows, and PCs in the Novell NetWare network. Logical data backup and restore actions for any file or disk partition in a Unix system and for any file in a PC system can be performed automatically and at defined times during an operation. The backup media are tapes, DAT cartridges, magneto-optical disks, and associated autochangers and jukeboxes. >

A study of the coverage of large-scale sensor networks

Abstract: We study the coverage properties of large-scale sensor networks. Three coverage measures are defined to characterize the fraction of the area covered by sensors (area coverage), the fraction of sensors that can be removed without reducing the covered area (node coverage), and the capability of the sensor network to detect objects moving in the network (detectability), respectively. We approach the coverage problem from a theoretical perspective and explore the fundamental limits of the coverage of a large-scale sensor network. We characterize the asymptotic behavior of the coverage measures for a variety of sensor network scenarios. We find that the coverage of a sensor network exhibits different behaviors for different network configuration and parameters. Based on the analytical characterizations of the network coverage, we further discuss the implications to network planning and protocol performance of sensor networks.

Cellular Traffic Offloading through WiFi Networks

Abstract: Cellular networks are currently facing the challenges of mobile data explosion. High-end mobile phones and laptops double their mobile data traffic every year and this trend is expected to continue given the rapid development of mobile social applications. It is imperative that novel architectures be developed to handle such voluminous mobile data. In this paper, we propose and evaluate an integrated architecture exploiting the opportunistic networking paradigm to migrate data traffic from cellular networks to metropolitan WiFi access points (APs). To quantify the benefits of deploying such an architecture, we consider the case of bulk file transfer and video streaming over 3G networks and simulate data delivery using real mobility data set of 500 taxis in an urban area. We are the first to quantitatively evaluate the gains of citywide WiFi offloading using large scale real traces. Our results give the numbers of APs needed for different requirements of quality of service for data delivery in large metropolitan area. We show that even with a sparse WiFi network the delivery performance can be significantly improved. This effort serves as an important feasibility study and provides guidelines for operators to evaluate the possibility and cost of this solution. Keywords-Cellular traffic offloading, delay tolerant, WiFi access points, trace-driven simulation.