Waltenegus Dargie

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regions groups sensors together using certain neighborhood relationships, e.g. “the set of nodes within distance d”. Discovery of region members can be achieved using periodic advertisements. In EnviroTrack, groups are formed by sensors which detect certain user-defined entities in the physical world, with one group formed around each entity. Groups are(More)
syntax notation one (ASN.1),<lb>85, 86, 100, 104<lb>Accessibility, 98, 302, 362<lb>Acronym newsputer, 200<lb>Active knowledge, 197−210<lb>Ad hoc PSN, 96, 124<lb>Adaptive and intelligent educational<lb>systems (AIES), 359<lb>Adaptive hypermedia (AH), 355,<lb>357−359, 367, 369<lb>Adaptive navigation support, 357, 359<lb>Advanced distributed(More)
Live migration, the process of moving a virtual machine (VM) interruption-free between physical hosts is a core concept in modern data centers. Power management strategies use live migration to consolidate services in a cluster environment and to switch off underutilized machines to save power. However, most migration models do not consider the energy cost(More)
Wireless sensor networks are used for structure monitoring and border surveillance. Typical applications, such as sensors embedded in the outer surface of a pipeline or mounted along the supporting structure of a bridge, feature a linear sensor arrangement. Economical power use of sensor nodes is essential for long-lasting operation. In this paper, we(More)
The power consumption of presently available Internet servers and data centers is not proportional to the work they accomplish. The scientific community is attempting to address this problem in a number of ways, for example, by employing dynamic voltage and frequency scaling, selectively switching off idle or underutilized servers, and employing(More)
This paper introduces a mobility-aware medium access control protocol for multi-hop wireless sensor networks (MA-MAC). The protocol evaluates the RSSI values of acknowledgement packets and determines whether a gradual deterioration in the RSSI values eventually leads to a disconnection. If it does, it initiates a handover by switching transmission from a(More)
In wireless sensor networks nodes can be static or mobile, depending on the application requirements. Dealing with mobility can pose some formidable challenges in protocol design, particularly, at the link layer. These difficulties require mobility adaptation algorithms to localize mobile nodes and predict the quality of link that can be established with(More)
Energy-efficency is a key concern when designing protocols for wireless sensor networks (WSN). This is of particular importance in commercial applications where demonstrable return on investment is a crucial factor. One such commercial application that motivated this work is telemetry and control for freight railroad trains. Since a railroad train has a(More)