1 0 0 0 日本粘土学会参考試料の分析・評価
1 0 0 0 DLNA/UPnP-ZigBeeゲートウェイにおけるセンサ情報収集に関する性能評価(ユビキタスNW,一般,ホームネットワーク,ユビキタスネットワーク,コンテキストアウェア,eコマース及び一般)
- 著者
- 川本 良太 宮崎 伸夫 茂呂 一永 岡崎 大和 田中 数彦 原 誠一郎
- 出版者
- 一般社団法人電子情報通信学会
- 雑誌
- 電子情報通信学会技術研究報告. IN, 情報ネットワーク (ISSN:09135685)
- 巻号頁・発行日
- vol.108, no.289, pp.43-48, 2008-11-06
近年,ホームネットワーク分野においてコンテンツを共有するための規格であるDLNA対応の製品が普及してきている.また,センサネットワーク分野においては,低消費電力な無線通信規格であるZigBeeが注目されている.そこで我々は,これら2つの規格を連携することによってサービスの幅を拡大させるため,DLNA/UPnP-ZigBeeゲートウェイの研究開発を行っている.ゲートウェイではブロードキャストクエリにより全センサノードのセンサ情報を一斉に収集しているが,ノード数の増加に伴い,衝突の影響で応答のパケット到達率が低下する.本稿では,ゲートウェイを実装し,キャッシュの利用等によってパケットロスへの対策を講じた.また,オフィスビルのフロアを利用したセンサ情報収集実験による性能評価を行った.本実験により,パケット到達率の評価,及びキャッシュ機構の有効性を検証したので報告する.
1 0 0 0 OA アスベストとは何か?
- 著者
- 榊原 正幸 上原 誠一郎
- 出版者
- 一般社団法人 日本鉱物科学会
- 雑誌
- 岩石鉱物科学 (ISSN:1345630X)
- 巻号頁・発行日
- vol.35, no.1, pp.3-10, 2006 (Released:2006-03-01)
- 参考文献数
- 29
- 被引用文献数
- 2 1
The term asbestos is a generic designation given to six types of naturally occurring mineral fibers that are or have been used in commercial products. These fibers belong to two mineral groups: serpentines and amphiboles. The serpentine group contains a single asbestiform variety: chrysotile. The amphibole group contains five asbestiform amphibole varieties: anthophyllite, grunerite (amosite), riebeckite (crocidolite), tremolite and actinolite. These fibrous minerals share several properties which qualify them as asbestiform fibers. They are bundles of fibers which can be easily cleaved into thinner fibers. Several properties that make asbestos so versatile and cost effective are high tensile strength, chemical and thermal stability, high flexibility, and low electrical conductivity. Asbestos fibers have been used in a broad variety of industrial application; some 3000 applications such as roofing products, gaskets, and friction products. 80% of imported asbestos is used for cement products such as asbestos boards and slates which are used for building materials, 7% for friction materials, and less than 3% for asbestos textile. Nearly all of the asbestos produced worldwide is chrysotile. Historically, chrysotile has accounted for more than 90% of the world’s asbestos production, and it presently accounts for over 99% of the world production. Two types of amphiboles, commonly designated as amosite and crocidolite are no longer mined. With the onset of the health issues concerning asbestos in the late 1960s and early 1970s, world production and consumption began to decline during the 1980s. Japan used approximately 6.7 million tons between 1974 and 2004. About 67% of this amount was used since 1930. The relationship between workplace exposure to airborne asbestos fibers and respiratory diseases is one of the most widely studied subjects of modern epidemiology. The research efforts resulted in significant consensus that asbestos fibers can be associated with diseases of asbestosis, lung cancer and mesothelioma. Its carcinogenic nature, an overall lack of knowledge of minimum safe exposure levels, and the long latency for the development of lung cancer and mesothelioma are the main contributing factors to these controversies.