著者

NAKATANI Takako HORI Shouzo UBAYASHI Naoyasu KATAMINE Keiichi HASHIMOTO Masaaki

出版者

電子情報通信学会

雑誌

IEICE transactions on information and systems (ISSN:09168532)

巻号頁・発行日

vol.E93.D, no.8, pp.2182-2189, 2010-08

被引用文献数

1 2

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Requirements changes sometimes cause a project to fail. A lot of projects now follow incremental development processes so that new requirements and requirements changes can be incorporated as soon as possible. These processes are called integrated requirements processes, which function to integrate requirements processes with other developmental processes. We have quantitatively and qualitatively investigated the requirements processes of a specific project from beginning to end. Our focus is to clarify the types of necessary requirements based on the components contained within a certain portion of the software architecture. Further, each type reveals its typical requirements processes through its own rationale. This case study is a system to manage the orders and services of a restaurant. In this paper, we introduce the case and categorize its requirements processes based on the components of the system and the qualitative characteristics of ISO-9126. We could identify seven categories of the typical requirements process to be managed and/or controlled. Each category reveals its typical requirements processes and their characteristics. The case study is our first step of practical integrated requirements engineering.

著者

ADNAN SATO Mitsuhisa

出版者

電子情報通信学会

雑誌

IEICE transactions on information and systems (ISSN:09168532)

巻号頁・発行日

vol.E95-D, no.6, pp.1565-1576, 2012-06

被引用文献数

2

---

Lazy-task creation is an efficient method of overcoming the overhead of the grain-size problem in parallel computing. Work stealing is an effective load balancing strategy for parallel computing. In this paper, we present dynamic work stealing strategies in a lazy-task creation technique for efficient fine-grain task scheduling. The basic idea is to control load balancing granularity depending on the number of task parents in a stack. The dynamic-length strategy of work stealing uses run-time information, which is information on the load of the victim, to determine the number of tasks that a thief is allowed to steal. We compare it with the bottommost first work stealing strategy used in StackThread/MP, and the fixed-length strategy of work stealing, where a thief requests to steal a fixed number of tasks, as well as other multithreaded frameworks such as Cilk and OpenMP task implementations. The experiments show that the dynamic-length strategy of work stealing performs well in irregular workloads such as in UTS benchmarks, as well as in regular workloads such as Fibonacci, Strassen's matrix multiplication, FFT, and Sparse-LU factorization. The dynamic-length strategy works better than the fixed-length strategy because it is more flexible than the latter; this strategy can avoid load imbalance due to overstealing.

著者

OHKAWA Yasuhiro FUKUI Kazuhiro

出版者

電子情報通信学会

雑誌

IEICE transactions on information and systems (ISSN:09168532)

巻号頁・発行日

vol.E95.D, no.6, pp.1619-1627, 2012-06

被引用文献数

13 3

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This paper proposes a method for recognizing hand-shapes by using multi-viewpoint image sets. The recognition of a hand-shape is a difficult problem, as appearance of the hand changes largely depending on viewpoint, illumination conditions and individual characteristics. To overcome this problem, we apply the Kernel Orthogonal Mutual Subspace Method (KOMSM) to shift-invariance features obtained from multi-viewpoint images of a hand. When applying KOMSM to hand recognition with a lot of learning images from each class, it is necessary to consider how to run the KOMSM with heavy computational cost due to the kernel trick technique. We propose a new method that can drastically reduce the computational cost of KOMSM by adopting centroids and the number of images belonging to the centroids, which are obtained by using k-means clustering. The validity of the proposed method is demonstrated through evaluation experiments using multi-viewpoint image sets of 30 classes of hand-shapes.

著者

Komain PIBULYAROJANA 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.E80.B, no.1, pp.116-126, 1997-01

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Banyan networks are used in multiprocessor computer applications for an ATM switching. In this paper, we study the continuous blocking of the the first n-stage which makes the performance of the banyan networks decrease. We use the 2-dilated banyan networks into the banyan networks to remove the the continuous blocking of the the first n-stage. We call the new networks as the hybrid dilated banyan networks. We explain how to analyze the throughput of this networks at each stage. Based on the analysis of input rate and output rate at each stage, we can design the hybrid dilated banyan networks with the desirable output rate. The result of analysis shows the hybrid dilated banyan networks have higher performance and feasibility than the banyan networks.

著者

PIBULYAROJANA Komain 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.E80.B, no.12, pp.1816-1818, 1997-12

---

Many switching networks are currently designed to support ATM architectures. In this letter, we propose the performance improvement of a network called hybrid dilated banyan network with bypasses at the stage of 4×2 re-arrangeable output switch. Our letter also includes the performance analysis of the improved hybrid dilated banyan network.

著者

CHEN Hongbing 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.E81.B, no.1, pp.45-57, 1998-01

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The Optimal Packet Length (OPL) in packet-switched communication systems has been studied in the literature from various aspects. In this paper, we consider the trade-off between packet length and data transmission delay in a high-speed communication system. To simplify the analysis of the mean data transmission de[ay, the model is limited to a point-to-point communication system, in which each node complies with the OSI reference model. In order to study the relationship between the OPL and the number of modules performing each protocol, two model communication systems are discussed. In one each node contains two layered protocol modules, and in the other three. Moreover, for both models, the mean data transmission delay is analyzed for two cases depending on whether or not the DLC layer or the network layer performs retransmissions. After studying the OPL which minimizes the mean data transmission delay in each case, we discuss the relationships between the OPLs and the various protocol parameters.

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.E82.B, no.9, pp.1432-1438, 1999-09

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This paper presents the generator polynomial matrices and the upper bound on the constraint length of punctured convolutional codes (PCCs), respectively. By virtue of these properties, we provide the puncturing realizations of the good known nonsystematic and systematic high rate CCs.

著者

PIBULYAROJANA Komain 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.E83.B, no.7, pp.1474-1487, 2000-07

---

Banyan networks and their improved switches such as 2-dilated banyan networks are usually constructed by a self-routing mechanism, and provide a high multiplexing transmission capacity to ATM networks.Due to cell blocking in the switching elements in these banyan networks, however, cell loss is occurred and then the throughput of each network is decreased.To improve this problem, we have introduced bypasses to the original and the 2-dilated banyan networks.This paper focuses on the position of the bypasses in these banyan networks and proposes the one-bypass-connection methods in order to minimize cell transfer delay caused by the bypasses.We also analyze output rate of each network and show that the bypass method gives network designers flexible selections for network performance and transfer delay.

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

---

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

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

---

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.

著者

三代 謙仁 川村 隆浩 中川 博之 田原 康之 大須賀 昭彦

出版者

電子情報通信学会

雑誌

電子情報通信学会論文誌. D, 情報・システム = The IEICE transactions on information and systems (Japanese edition) (ISSN:18804535)

巻号頁・発行日

vol.94, no.11, pp.1791-1799, 2011-11-01

参考文献数

19

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近年,食や環境への意識の高まりから野菜作りやインテリアグリーンに関心が集まっている.しかし,都市の限られた環境で緑を育てるのは容易ではなく,その環境に適した植物を選択するには専門的な知識が必要ということもあり,不用意に繁茂させたり,逆に枯らしてしまうケースも多い.また,インテリア/エクステリアとしては周辺環境との調和が気になるが,成長時の生い茂った姿を想像するのは素人には難しい.そこで本論文では,携帯電話のセンサを用いて,植裁スペースの環境(日照,温度,気温等)に適した植物を推薦するエージェントシステムの開発について述べる.また,本システムでは,推薦した植物の成長した姿を3DCGで表示するという拡張現実手法を用いて,周辺の景観とマッチするかどうかを視覚的に確認することもできる.これにより,植物や園芸に関する特別な知識がなくとも,環境に適しており,かつ周辺の景観との調和のとれた植物を選ぶことが可能となる.今回の実験では約70%の精度で適した植物を推薦できることを確認できた.

著者

岡 宏典 岡田 啓 間瀬 憲一

出版者

電子情報通信学会

雑誌

電子情報通信学会技術研究報告 (ISSN:09135685)

巻号頁・発行日

vol.109, no.381, pp.79-84, 2010-01-21

被引用文献数

1

著者

会田 雅樹 高野 知佐 小頭 秀行 中村 元

出版者

電子情報通信学会

雑誌

電子情報通信学会論文誌. B, 通信 = The transactions of the Institute of Electronics, Information and Communication Engineers. B (ISSN:13444697)

巻号頁・発行日

vol.93, no.10, pp.1430-1444, 2010-10-01

被引用文献数

1

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通信ネットワークに関する各種データ(トラヒック量,ユーザ数等)には,何らかの形で人間社会の活動の特性が反映されていると考えることができる.我々はこれまで,情報通信サービスのデータに現れるべき乗則を利用して,人間の情報交換関係に関する社会ネットワークの構造を調べてきた.結果として得られた社会ネットワークの構造は,分析のもとになった特定の情報通信サービスのデータに関する表面的なサービス種別に左右されるものではなく,背後にある普遍的な社会ネットワーク構造を記述していることが望ましい.これを確認するためには,特定のデータ分析から得られる社会ネットワーク構造の分析結果を,他の通信サービスのデータによって検証することが有効であると考えられる.本論文では,複数の情報通信サービスのデータを相補的に用いて,データの自己無撞着性から許される社会ネットワークの構造やユーザ行動特性の分析を行う.また,得られた次数分布特性が現実のデータとよく一致することを確認する.

著者

平栗 健史 永田 健悟 西森 健太郎

出版者

電子情報通信学会

雑誌

電子情報通信学会技術研究報告 (ISSN:09135685)

巻号頁・発行日

vol.110, no.129, pp.25-29, 2010-07-15

被引用文献数

2

著者

塩地 貴史 川上 弘幸 梅田 英和

出版者

電子情報通信学会

雑誌

電子情報通信学会技術研究報告 (ISSN:09135685)

巻号頁・発行日

vol.109, no.145, pp.19-24, 2009-07-23

被引用文献数

2