Wireles s Sensor Networks (WSNs) are increasingly being used for various information collection in the future. For many applications, a large number of sensors in an active wireless network are more effective and preferabl e to a few expensive wireless sensors. Location discovery of sensor nodes after they have been deployed is known as a challenge, especially for moving sensors. Algorithms based on radio signal strength indication are considered as the lowest cost method to solve localization problem. But in practice, the accuracy of signal strength indication algorithm varies with the average distances between wireles s nodes -the nearer, the better. Th is paper describes a new integrated dynamic localization algorithm, based on Received Signal Strength Indication (RSS I) and Multidimensional Scaling (MDS) algorithm. In this concept, signals with RSSI values among beacon nodes could help to generate a real time 2D map of the network by self iterations. Un known nodes use the map to determine their locations in this region. A software simul ator is created to tes t the performance of the al gorithm, and practical experiments al so show the development of localization accuracy and efficiency.
Relays are expected to be included in 3GPP Release 10 also known as LTE-Advanced (LTE-A). Relays can be used to improve coverage and throughput and could be an important tool to improve the wireless experience. In this paper, the discussion on relay technologies in 3GPP LTE-A is overviewed firstly. Because both low cost and small delay make L1 relay more attractive than other types of relay, the SINR and information rate performance of L1 relays are analyzed mainly in this paper. With a simple one-dimensional relay model and an approximate self-interference model, the capability of L1 relays to improve cell-edge throughput is verified.
Parallel file systems usually provide a unified storage solution, which fails to meet specific application needs. In this paper, we propose an extended file handle scheme to address this problem. It allows the file systems to specify optimizations for individual file or directory based on workload characteristics. One case study shows that our proposed approach improves the aggregate throughput of large files and small files by up to 5% and 30%, respectively. To further improve the access performance of small files in parallel file systems, we also propose a new metadata-based small file optimization method. The experimental results show that the aggregate throughput of small files can be effectively improved through our method.
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