Network lifetime predictability is an essential system requirement for the type of wireless sensor network (WSN) used in safety-critical and highly-reliable applications. All sensor nodes in these time-critical WSNs should meet the lifetime constraint at any time instance, else it may cause severe consequences that involve economic losses, or even fatalities. In the literature, clustering sensors into groups is a popular strategy to maximize the network lifetime, but none of the clustering algorithms address the predictability issue for time-critical WSNs. In this paper, the High Energy First (HEF) clustering algorithm is chosen as a design reference model, which is proved in this paper to be an optimal clustering policy under certain ideal conditions. To address network lifetime predictability in practice, the network lifetime bounds and feasibility test for the HEF are developed via the worst case energy consumption analysis. The network simulator 2 (NS2) is used to verify the proposed network lifetime predictability model, and the results show that the derived bounds of the predictability provide accurate estimations of the system lifetime.

Schedulability Analysis for Hard Network Lifetime Wireless Sensor Networks With High Energy First Clustering

 Abstract— Wireless Sensor Network is a resource constraint network, in which all sensor nodes have limited resources. In order to save resources and energy data must be aggregated to reduce the amount of traffic in the network. Data aggregation has to done with the help of clustering scheme. Clusters reduce the localized traffic by means of grouping sensor nodes and compress the data together and then transmit only compact data to base station. Therefore optimal cluster head selection is important to maximize the lifetime of the network by utilizing the limited energy in an efficient manner. Various algorithms are proposed for the selection of cluster head for maximizing the network life time. This paper is focused on the survey of such algorithms.

A Survey on Algorithms for Cluster Head Selection in WSN

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http://www.fp.utm.my/epusatsumber/pdffail/ptkghdfwP2/Lee%20Mei%20Yun.TP.pdf

Declaration of thesis / undergraduate project paper and copyright

According to machinery statistics of the Ministry of Economy, Trade and Industry, the quantity of electric lamps produced in Japan was 613,000,000 (68.1% compared to the previous year). Of these, 73,000,000 were general lamps (88.1% compared to the previous year) and 32,000,000 were halogen lamps (79.3% compared to the previous year). The number of fluorescent lamps produced was 627,000,000 (72.9% compared to the previous year), and the number of general fluorescent lamps excluding backlights was 240,000,000 (86.0% compared to the previous year). Furthermore, the number of HID lamps produced was 7,600,000 (75.6% compared to the previous year). On the other hand, when looking at the sales amounts compared to the previous year, the results for general lighting electric lamps, halogen lamps, general fluorescent lamps, backlights, and HID lamps were 88.5%, 87.7%, 91.6%, 49.1%, and 76.4%, respectively. For compact fluorescent lamps, which are included within the numbers for general fluorescent lamps, sales amounts were 92.7% compared to the previous year, which was a large drop from 137.3% in 2008. The main causes mentioned for the decreases in production numbers and sales volume for these mainstream lamps are generally the economic recession and the rise of LEDs, a new light source that is now being used in the general lighting field. The main exhibition domestically was Lighting Fair 2009 held in March at Tokyo Big Sight. Internationally, it was Light Fair held in New York City in May. Although some new types of and research results for incandescent electric lamps are seen, their use and production continues to be stopped worldwide due to their low luminescence efficiency. In particular, the EUP directive (a directive related to energy using products and now named the ERP directive) was enacted in Europe in September. The sales of white diffused and clear types of incandescent electric lamps of 100 W or more and halogen lamps are prohibited. In Japan as well, major manufacturers continue to stop or reduce production of incandescent electric lamps. With fluorescent lamps, development into energy efficiency and longer life is healthy and new product releases of compact fluorescent lamps and ring fluorescent lamps are seen. Furthermore, the issue of reducing the amount of enclosed mercury remains and the IEC is continuing validity investigations of measurement methods. For light emitting diode (LED) light sources, 2009 was the year they saw full-fledged commercial viability and it may be remembered as the year that LEDs started to receive attention from average consumers. The luminescence efficiency of individual chips was reported to have reached 250 lm/W at the research level. In the Japanese production industry, the current market price of LED light bulbs quickly dropped to almost a third between the beginning and the end of the year. This drop is believed to be due to competition between the main existing light source manufacturers and manufacturers newly entering the market, the development and market introduction of LED products, and the flow of manufacturing processes to developing countries with cheap labor costs. In high-intensity discharge (HID) lamp field, product development and technological research related to ceramic metal halide lamps is as popular as ever. With increased emphasis on environmental conservation, mercury-free ceramic metal halide lamps are also being announced as reference exhibits at exhibitions. While reports regarding HID lamps cover fundamental research, reports of applications for growing plants are also being seen. There are also many reports about other types discharge lamps, including electrodeless lamps that use inductively-coupled mercury, microwave discharge lamps, and excimer discharge lamps. Furthermore, there are many reports about application examples of the nanotechnology as a new light source. With regard to lighting circuits, (…)

Light Sources and Lighting Circuits

本稿では, 格フレーム辞書を漸次的に自動構築する手法を提案する.カバレージの高い格フレーム辞書を構築するために, 大規模コーパスから徐々に確からしい情報を抽出する.まず, コーパスを構文解析し, 構文的曖昧性のない述語項構造のみを抽出・クラスタリングすることによって, 1次格フレーム辞書を得る.次に, 1次格フレーム辞書を用いてコーパスを格解析し, 新たに分かる確実な情報を抽出し, 2次格フレーム辞書を構築する.このように徐々に新たな情報を加えていくことによって, 高次格フレーム辞書を構築する.結果として得られた格フレーム辞書は, 二重主語構文, 連体修飾の外の関係, 格変化といった複雑な言語現象を解析することを可能にする.新聞記事26年分, 約2600万文のコーパスから格フレーム辞書を構築し2種類の評価を行った.1つは, 得られた格フレームを人手で評価するものであり, もう1つは得られた格フレーム辞書を用いた構文・格解析実験による評価である.これらの結果, 本手法の有効性が確かめられた.

Gradual Fertilization of Case Frames

Sensor networks require energy-aware, efficient datacollecting methods to extend their network lifetime. In this paper, we propose an energy-efficient data gathering mechanism which clusters sensor nodes and forms a distributed data-routing tree based on in-network data fusion. In our mechanism, the cluster formation and the data-routing tree construction are simultaneously carried out so that they reduce their energy required to organize a multi-hop routing tree of sensed data. The mechanism also performs data aggregation at each member node to reduce the amount of transmission data. Moreover our work distributes energy load to each node to avoid the intensive energy consumption of a cluster-head. Experimental results show that our data gathering mechanism outperforms the direct scheme protocol and the LEACH protocol on the point of view of the network lifetime.

/pdf/a-data-gathering-mechanism-based-on-clustering-and-in-3ybbhg2m83.pdf

峯恒憲

Papers

A Data Gathering Mechanism based on Clustering and In-Network processing Routing Algorithm

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峯 恒憲

Papers

A Data Gathering Mechanism based on Clustering and In-Network processing Routing Algorithm

A Method for Relevance Calculation between Browsed Web Pages toward Personalized Recommendation System

Sense Discrimination of Verbs Using EDR Dictionary

Sense Discrimination of Verbs Using EDR dictionaries and EDR Corpora

峯恒憲