著者

OHZAHATA Satoshi KIMURA Shigetomo EBIHARA Yoshihiko

出版者

電子情報通信学会

雑誌

IEICE transactions on communications (ISSN:09168516)

巻号頁・発行日

vol.E84.B, no.4, pp.752-759, 2001-04

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Mobile IP can provide macro mobility for a mobile node (MN) instead of the original IP communication. Since the orignal Mobile IP does not consider micro mobility, it can not avoid handoff latency. The latency causes packets loss or large variations of the delivery times. To prevent it, several methods are proposed to improve the orignal Mobile IP handoff method. In our previous work, we proposed the fast registration method which enabled an MN to have two communication routes from the home agent (HA), and realized lower latency in the handoff procedures by the doublecasting on the two communication routes. But, the simulation results also show that the proposed method still has large overhead. This paper presents a seamless handoff method, which improves the fast registration method. In the method, the MN can know the first and second suitable base stations for the communications through information from the MAC media. The control helps for seamless handoff in case that the MN must frequently change its current base station (BS). The computer simulations for Constant Bit Rate (CBR) over real-time transport protocol (RTP) flow shows that the proposed method provides no handoff latency with low overhead even if the MN must occur frequcnt handoffs in a second.

著者

SUN Zhenqiang KIMURA Shigetomo EBIHARA Yoshihiko

出版者

電子情報通信学会

雑誌

IEICE transactions on communications (ISSN:09168516)

巻号頁・発行日

vol.E84.B, no.5, pp.1319-1327, 2001-05

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In the wireless asynchronous transfer mode (ATM) networks, a custom data link control (DLC) layer protocol with stronger error correction ability is needed for mitigating the affect of radio channel errors. This paper applies punctured turbo code schemes to the protection of the header and various payloads in wireless ATM cell, which are realized by the combination of programmable interleaving and puncturing. Their performance is analyzed for Rayleigh fading channel, which shows more significant reduction in cell loss rate (CLR) than the previous systems. Our proposal also provides good balance designs for CLR and the payload bit error rate (BER), and offers potential for future evolutionary improvement of the wireless ATM codingscheme.

著者

OHZAHATA Satoshi KIMURA Shigetomo EBIHARA Yoshihiko KAWASHIMA Konosuke

出版者

電子情報通信学会

雑誌

IEICE transactions on communications (ISSN:09168516)

巻号頁・発行日

vol.E90.B, no.8, pp.2070-2080, 2007-08

被引用文献数

1 2

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In this paper we propose a cross-layer retransmission control for TCP communication over a wireless link. With our proposed control, a retransmission delay for lost packet is reduced, packet losses in the wireless link are eliminated and all packets are delivered in the correct order. No change is required to TCP itself or to the sender. Our proposed method is implemented in a queue between the media access control (MAC) layer and logical link layer in a base station, and is designed to assist local retransmission control in the MAC layer. Computer simulations show that our proposed method can maximally use the bandwidth of the wireless link under high bit error rates conditions with conventional TCP control. The fairness problem of TCP communication between connections with different bit error rates in a wireless link is also improved, and MAC level fairness is also controllable.

著者

SHOMURA Yusuke WATANABE Yoshinori YOSHIDA Kenichi

出版者

Institute of Electronics, Information and Communication Engineers

雑誌

IEICE transactions on communications (ISSN:09168516)

巻号頁・発行日

vol.E91.B, no.6, pp.1896-1905, 2008

被引用文献数

12 11

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Abnormal traffic that causes various problems on the Internet, such as P2P flows, DDoS attacks, and Internet worms, is increasing; therefore, the importance of methods that identify and control abnormal traffic is also increasing. Though the application of frequent-itemset-mining techniques is a promising way to analyze Internet traffic, the huge amount of data on the Internet prevents such techniques from being effective. To overcome this problem, we have developed a simple frequent-itemset-mining method that uses only a small amount of memory but is effective even with the large volumes of data associated with broadband Internet traffic. Using our method also involves analyzing the number of distinct elements in the itemsets found, which helps identify abnormal traffic. We used a cache-based implementation of our method to analyze actual data on the Internet and demonstrated that such an implementation can be used to provide on-line analysis of data while using only a small amount of memory.

著者

SUZUKI Kazuya JIBIKI Masahiro YOSHIDA Kenichi

出版者

電子情報通信学会

雑誌

IEICE transactions on communications (ISSN:09168516)

巻号頁・発行日

vol.E93.B, no.5, pp.1085-1094, 2010-05

被引用文献数

2

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The availability of IP networks has increased its importance due to the evolving use of real-time and mission-critical applications on IP networks. Methods for preparing alternate routing tables that can be used for fast restoration from link failures have been investigated. In such methods, each node has to compute a number of alternate routing tables in advance since they have to prepare for each potential failure. The resulting huge number of alternate routing tables has prevented these methods from being deployed. In this paper, we propose a method for reducing the number of alternate routing tables for link failure. It analyzes three types of shortest path trees on the basis of link-state information. We show that the number of alternate routing tables can be reduced to 1/100, on average, from that with the conventional method, and that they are small enough to be stored in the memory of IP routers.

著者

ROMANOV Anton OKAMOTO Eiji

出版者

電子情報通信学会

雑誌

IEICE transactions on communications (ISSN:09168516)

巻号頁・発行日

vol.E93.B, no.6, pp.1411-1421, 2010-06

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With the increasing demand for services provided by communication networks, quality and reliability of such services as well as confidentiality of data transfer are becoming ones of the highest concerns. At the same time, because of growing hacker's activities, quality of provided content and reliability of its continuous delivery strongly depend on integrity of data transmission and availability of communication infrastructure, thus on information security of a given IT landscape. But, the amount of resources allocated to provide information security (like security staff, technical countermeasures and etc.) must be reasonable from the economic point of view. This fact, in turn, leads to the need to employ a forecasting technique in order to make planning of IT budget and short-term planning of potential bottlenecks. In this paper we present an approach to make such a forecasting for a wide class of information security related incidents (ISRI) — unambiguously detectable ISRI. This approach is based on different auto regression models which are widely used in financial time series analysis but can not be directly applied to ISRI time series due to specifics related to information security. We investigate and address this specifics by proposing rules (special conditions) of collection and storage of ISRI time series, adherence to which improves forecasting in this subject field. We present an application of our approach to one type of unambiguously detectable ISRI — amount of spam messages which, if not mitigated properly, could create additional load on communication infrastructure and consume significant amounts of network capacity. Finally we evaluate our approach by simulation and actual measurement.

著者

YAMADA Takeshi KASUYA Yuki SHINOHARA Yuki KITAWAKI Nobuhiko

出版者

電子情報通信学会

雑誌

IEICE transactions on communications (ISSN:09168516)

巻号頁・発行日

vol.E93.B, no.6, pp.1367-1372, 2010-06

被引用文献数

1 4

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This paper describes non-reference objective quality evaluation for noise-reduced speech. First, a subjective test is conducted in accordance with ITU-T Rec. P.835 to obtain the speech quality, the noise quality, and the overall quality of noise-reduced speech. Based on the results, we then propose an overall quality estimation model. The unique point of the proposed model is that the estimation of the overall quality is done only using the previously estimated speech quality and noise quality, in contrast to conventional models, which utilize the acoustical features extracted. Finally, we propose a non-reference objective quality evaluation method using the proposed model. The results of an experiment with different noise reduction algorithms and noise types confirmed that the proposed method gives more accurate estimates of the overall quality compared with the method described in ITU-T Rec. P.563.

著者

Koga Hiroki

出版者

電子情報通信学会

雑誌

IEICE transactions on fundamentals of electronics, communications and computer sciences (ISSN:09168508)

巻号頁・発行日

vol.E94.A, no.11, pp.2073-2082, 2011-11

被引用文献数

2 3

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In information-spectrum methods proposed by Han and Verdú, quantities defined by using the limit superior (or inferior) in probability play crucial roles in many problems in information theory. In this paper, we introduce two nonconventional quantities defined in probabilistic ways. After clarifying basic properties of these quantities, we show that the two quantities have operational meaning in the eps-coding problem of a general source in the ordinary and optimistic senses. The two quantities can be used not only for obtaining variations of the strong converse theorem but also establishing upper and lower bounds on the width of the entropy-spectrum. We also show that the two quantities are expressed in terms of the smooth Rényi entropy of order zero.

巻号頁・発行日

1869

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統計 / 和装 / 明治2年

著者

堀池 信夫 HORIIKE NOBUO

巻号頁・発行日

2011

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課題番号:20320008

著者

鈴木 博

出版者

京都大学経済学会

雑誌

經濟論叢 (ISSN:00130273)

巻号頁・発行日

vol.183, no.4, pp.41-56, 2009-10

著者

小口 千明

出版者

筑波大学歴史・人類学系歴史地理学研究室

雑誌

歴史地理学調査報告 (ISSN:09152504)

巻号頁・発行日

no.8, pp.111-118, 1998-03

著者

大賀 祐樹

出版者

早稲田大学大学院 社会科学研究科

雑誌

社学研論集 (ISSN:13480790)

巻号頁・発行日

vol.7, pp.63-78, 2006-03-25

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論文

著者

大塚 秀高

出版者

東京大学東洋文化研究所

雑誌

東洋文化研究所紀要 (ISSN:05638089)

巻号頁・発行日

vol.124, pp.79-134, 1994-03

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以平話為書名的「小説」有両種。 一種是宋末元初刊本之『新編五代史平話』,一種是元至治年間建安虞氏所刊行之「全相平話五種」。 它們在版式和史観表現方面各有特色。 前者好像比較尊重民族的血統,而後者却似乎更尊重王朝的正統一這在其代表作『三国志平話』中猶為明所顕。 明代成書的『残唐五代史演義伝』中也可看出跟『三国志平話』同様的史観。 依我所見,早在『残唐五代史演義伝』成書之前已応該有「残唐平話」。 『残唐五代史演義伝』基本保持了它的史観,而『新編五代史平話』則是根拠史書改編而成的。 『新編五代史平話』之創作改変是単独而先行的。 但到了明代嘉靖年間,却掀起改編講史章回小説的高潮。 比如熊大木編纂的現存之『唐書志伝通俗演義』和『大宋演義中興英烈伝』,都由楊氏清白堂・清江堂出版。 已佚而曽経存在的熊大木編纂的,除上述両種外,還有『列国志伝』『全漢志伝』『南北宋志伝』。 這些作品,拠我所知,都是嘉靖後半由楊氏両清堂刊行,而万暦年間,在南京由周氏万巻楼(仁壽堂)・大業堂和唐氏世徳堂,附上上元王少淮写像相継刊行,在福建由余氏三台館以上図下文形式刊行出版。 在這不但時期而且地点也不同的三次出版中,熊大木編纂的本子(嘉靖定本)所用的分則形式漸次変化,以至誕生了新的分回形式本子即万暦新本。 根拠版本和挿図之画工来判断,可以認定和上述五種講史章回小説同様『東西晋志伝通俗演義』也早已有嘉靖定本,只不過現在佚失罷了。 拠上元王少淮写像的挿図来看,『英烈伝』之余君召三台館刊本,恐怕是南京出版的。 它的南京斉府原板也有可能為嘉靖定本。 熊大木不但拠史書来改変旧本(原本)小説(恐怕是平話或者平話系統的本子)的荒誕無稽,而且記下他改変的根拠等。 這由嘉靖定本(及其系統之版本)中常々発現「旧本○○」「小説○○」等註記可以得到説明。 嘉靖定本之中還有附上彩絵図之内府抄本。 内府除了以抄本形式向皇帝・皇后等提供娯楽外,還以刊本形式向一般読者提供閲読講史章回小説的方便。 但培養忠義・英烈等封建思想則是其真正的目的之所在。 這従忠義・英烈的詞匯出現在書名上可以得到説明。 我想,在推動小説生成的歴史上郭勛之存在很重要,而嘉靖定本之出現和郭勛之所作密接相関。 特別是把小説創作作為到達某種政治目的的一種手段的作為更是引人注目。 拠『皇明従信録』所註,郭勛為他的五世祖郭英写了『国朝英烈記』。 這『国朝英烈記』和南京斉府本『英烈伝』相当有関係。 也正是受到郭勛的創作意図的影響纔能誕生了武定板『三国通俗演義』和『水滸伝』。

著者

田岡 絵理子

出版者

早稲田大学法学会

雑誌

早稻田法学会誌 (ISSN:05111951)

巻号頁・発行日

vol.58, no.2, pp.359-412, 2008-03-25

著者

李 暢 松縄 正登

出版者

「図書館情報メディア研究」編集委員会

雑誌

図書館情報メディア研究 (ISSN:13487884)

巻号頁・発行日

vol.10, no.1, pp.31-45, 2012-09-28

著者

片山 ふみ 後藤 嘉宏

出版者

「図書館情報メディア研究」編集委員会

雑誌

図書館情報メディア研究 (ISSN:13487884)

巻号頁・発行日

vol.10, no.1, pp.11-29, 2012-09-28

著者

梶浦 久江 中山 伸一

出版者

「図書館情報メディア研究」編集委員会

雑誌

図書館情報メディア研究 (ISSN:13487884)

巻号頁・発行日

vol.10, no.1, pp.1-10, 2012-09-28

著者

三宅 和夫

出版者

北海道大學教育學部 = THE FACULTY OF EDUCATION HOKKAIDO UNIVERSITY

雑誌

北海道大學教育學部紀要 (ISSN:04410637)

巻号頁・発行日

vol.15, pp.29-37, 1968-03

著者

岡本 健

出版者

日本ホスピタリティ・マネジメント学会

雑誌

HOSPITALITY (ISSN:13428225)

巻号頁・発行日

vol.16, pp.129-136, 2009-03-31