Current Issue : October - December Volume : 2015 Issue Number : 4 Articles : 4 Articles
Neighbor discovery is a significant research topic in wireless sensor networks. After wireless sensor devices are deployed in specific\nareas, they attempt to determine neighbors within their communication range. This paper proposes a new Block design-based\nAsynchronous Neighbor Discovery protocol for sensor networks called BAND. We borrow the concept of combinatorial block\ndesigns for neighbor discovery. First, we summarize a practical challenge and difficulty of using the original block designs. To\naddress this challenge, we create a new block generation technique for neighbor discovery schedules and provide a mathematical\nproof of the proposed concept. A key aspect of the proposed protocol is that it combines two block designs in order to construct\na new block for neighbor discovery.We analyze the worst-case neighbor discovery latency numerically between our protocol and\nsome well-known protocols in the literature. Our protocol reveals that the worst-case latency ismuch lower than others. Finally, we\nevaluate the performance of BANDand existing representative protocols through the simulation study.The results of our simulation\nstudy show that the average and maximum latency of BAND is about 40% lower than that of existing protocols. Furthermore, BAND\nspends approximately 30% less energy than others during the neighbor discovery process....
Dense Wireless Sensor Network Clouds have an inherent issue of latency and\npacket drops with regards to data collection. Though there is extensive literature that tries to\naddress these issues through either scheduling, channel contention or a combination of the\ntwo, the problem still largely exists. In this paper, a Clustered Multi-Channel Scheduling\nProtocol (CMSP) is designed that creates a Voronoi partition of a dense network. Each\npartition is assigned a channel, and a scheduling scheme is adopted to collect data within the\nVoronoi partitions. This scheme collects data from the partitions concurrently and then passes\nit to the base station. CMSP is compared using simulation with other multi-channel protocols\nlike Tree-based Multi-Channel, Multi-Channel MAC and Multi-frequency Media Access\nControl for wireless sensor networks. Results indicate CMSP has higher throughput and data\ndelivery ratio at a lower power consumption due to network partitioning and hierarchical\nscheduling that minimizes load on the network....
LopNur once was a huge lake located in northwesternChina.At present, there is no surface water in LopNur Lake basin and on SAR\nimages it looks like an ââ?¬Å?Ear.ââ?¬ÂThe objective of this paper is to retrieve the depth of subsurface brine layer in Lop Nur by copolarized\nphase difference of surface scattering. Based on field investigation and analysis of sample properties, a two-layer scattering structure\nwas proposed with detailed explanations of scattering mechanisms. The relationship between copolarized phase difference and the\nbrine layer depth in the region of Lop Nur were studied. The copolarized phase difference of surface scattering was extracted by\nmodel-based polarimetric decomposition method. A good linear correlation between measured subsurface brine layer depth and\ncopolarized phase difference with R2 reaching 0.82 was found. Furthermore, the subsurface brine layer depth of the entire lake area\nwas analyzed. According to the retrieved maps, some interesting phenomena were found, and several hypotheses about the past\nwater withdrawal process and the environmental evolution had been proposed to theoretically explain these phenomena. Based\non the penetration capability of SAR the reconstruction of historical evolution process of Lop Nur will be an interesting topic for\nfuture research....
Interest in and deployment of wireless monitoring systems is increasing in many\ndiverse environments, including row-crop agricultural fields. While many studies have been\nundertaken to evaluate various aspects of wireless monitoring and networking, such as\nelectronic hardware components, data-collection procedures, power management, and\ncommunication protocols, little information related to physical deployment issues has been\nreported. To achieve acceptable wireless transmission capability, the radio/antenna must be\npositioned properly relative to the ground surface or crop canopy to minimize degradation\nof the radio signal, usually requiring the mounting of the radio/antenna above the canopy.\nThis results in the presence of obstacles to normal agricultural equipment traffic and\nproduction operations and potential damage to the wireless monitoring system. A simple and\nrugged radio/antenna mounting system was designed which could be subjected to encounters\nwith agricultural equipment without suffering physical damage. The mounting system was\ndeployed and tested, and operated successfully following repeated encounters with various\nagricultural machines and implements. The radio/antenna mount is simple and inexpensive\nto fabricate using locally available components....
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