著者

村井 淳 Jun Murai

出版者

関西外国語大学・関西外国語大学短期大学部

雑誌

研究論集 = Journal of Inquiry and Research (ISSN:03881067)

巻号頁・発行日

vol.91, pp.117-135, 2010-03

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ロシア革命後、ソヴェト当局は反革命勢力などを弾圧するために、収容所を設けた。その後、ソ連邦が成立すると、白海に浮かぶソロヴェツキー島に本格的な強制労働収容所が建設された。1930年代のスターリン時代には、インフラ整備などで労働力が必要なことから、強制労働収容所とそれを管理運営するグラーグ(収容所管理総局)システムが必要に応じて構築されていった。その切っ掛けを提案したのは、自らも最初は囚人であったフレンケリであった。30年代の大粛清などにより無実の人が逮捕され、新しく建設された強制労働収容所で過酷な無賃労働を強いられた。また、第二次世界大戦期には、ドイツ軍や日本軍などの捕虜も同様の労働を強いられた。その結果、スターリン時代に、数百万もの人々が死亡した。1953年スターリンの死とともに、この強制労働システムは急速に崩壊し、囚人や捕虜は釈放されていった。しかし、これらの強制労働はソ連の産業に貢献したが、長い目で見るとソ連崩壊の一因になった。

著者

Kotaro KATAOKA Keisuke UEHARA Masafumi OE Jun MURAI

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

IEICE TRANSACTIONS on Communications (ISSN:09168516)

巻号頁・発行日

vol.E95-B, no.7, pp.2200-2209, 2012-07-01

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In disaster sites of 2011 Tohoku Earthquake, digital communication was virtually unavailable due to the serious damage to the existing Internet and ICT resources. Thus there were urgent demands for recovering the Internet connectivity and first aid communication tools. This paper describes the design and deployment of networking systems that provide Internet connectivity using 3G mobile links or VSAT satellite links. In this paper we examine two approaches for post-disaster networking: quickly deployable package and on-demand networking. Based on a comparison of their characteristics and deployment experiences, this paper tries to extract lessons that contribute to improving the preparedness to another disaster. This paper also shares our significant operational experience acquired through supporting a maximum of 54 sites in Tohoku area including evacuation shelters, temporary hospitals and local government offices.

著者

Hajime Tazaki Rodney Van Meter Ryuji Wakikawa Keisuke Uehara Jun Murai

出版者

Information Processing Society of Japan

雑誌

Journal of Information Processing (ISSN:18826652)

巻号頁・発行日

vol.19, pp.118-128, 2011 (Released:2011-03-09)

参考文献数

26

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MANET for NEMO (MANEMO) is a new type of network that integrates multi-hop mobile wireless networks with global connectivity provided by Network Mobility (NEMO). Two factors limit the scalability of MANEMO: the volatility of topologically correct global addresses, and excessive traffic load caused by inefficient use of nested tunnels and the consequent redundant routing of packets. We propose NAT-MANEMO, which solves both problems by applying NAT for some mobile router addresses, bypassing tunnel nesting. This approach retains global addresses for mobile end nodes, preserving application transparency, and requires only minimal modification to existing specifications. Our ideas are evaluated using simulation and a proof of concept implementation. The simulation shows the additional signaling overhead for the route optimization introduced by our proposal is negligible compare to the bandwidth of an IEEE 802.11 link. The implementation confirms that route optimization reduces latency and improves throughput.

著者

Hajime TAZAKI Rodney Van METER Ryuji WAKIKAWA Thirapon WONGSAARDSAKUL Kanchana KANCHANASUT Marcelo DIAS DE AMORIM Jun MURAI

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

IEICE TRANSACTIONS on Communications (ISSN:09168516)

巻号頁・発行日

vol.E93-B, no.8, pp.2004-2011, 2010-08-01

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Motivated by the deployment of post-disaster MANEMO (MANET for NEMO) composed of mobile routers and stations, we evaluate two candidate routing protocols through network simulation, theoretical performance analysis, and field experiments. The first protocol is the widely adopted Optimized Link State Routing protocol (OLSR) and the second is the combination of the Tree Discovery Protocol (TDP) with Network In Node Advertisement (NINA). To the best of our knowledge, this is the first time that these two protocols are compared in both theoretical and practical terms. We focus on the control overhead generated when mobile routers perform a handover. Our results confirm the correctness and operational robustness of both protocols. More interestingly, although in the general case OLSR leads to better results, TDP/NINA outperforms OLSR both in the case of sparse networks and in highly mobile networks, which correspond to the operation point of a large set of post-disaster scenarios.