Faculty Profiles - FUNABIKI Nobuo

A Link Activation Scheduling Algorithm Considering Transmission Success Rates in Packet Radio Networks

TAJIMA Shigeto, FUNABIKI Nobuo, HIGASHINO Teruo

2005 ( 2 ) 81 - 86 2005.1

Language：Japanese Publisher：Information Processing Society of Japan (IPSJ)

In packet radio networks such as wireless local areas networks and ad-hoc mobile networks, periodic activations of the communication links between adjacent hosts by following the conflict-free link activation schedule is effective to realize the multi media streaming of motion pictures and voices. For better schedules, success rates of link activations should be considered, because packets may be lost before reaching receiving hosts when transmission path conditions are not good, even though these communication hosts are located within the range of radio transmissions. In this paper, we present a link scheduling algorithm for periodic link activations in packet radio networks when the transmission success rate is given for every link. In this algorithm, the number of activation times in one cycle is calculated for each link beforehand that satisfies the minimum success rate, and the schedule of activating the link by this number without conflict is found. Through simulations in randomly generated instances, we show that the schedule by our algorithm can reduce the total transmission time required to complete packet transmissions.

A proposal of an access-point allocation algorithm for WDS in wireless LAN

Other Link： http://id.nii.ac.jp/1001/00047069/

KUMANO Eiji, MITANI Chie, FUNABIKI Nobuo, NAKANISHI Toru

2005 ( 2 ) 45 - 50 2005.1

Language：Japanese Publisher：Information Processing Society of Japan (IPSJ)

The wireless distribution system (WDS) provides wireless connections between multiple access points (APs) to compose a large-scale wireless local area network (WLAN). In this paper, we formulate the AP allocation problem for WDS, and present its two-stage heuristic algorithm. In this problem, a feasible allocation of APs is requested, such that the total number of APs is not only minimized, but also the load of each AP is equalized. The proposed algorithm consists of the first stage of allocating APs in a regular interval and the second stage of improving their allocations by random perturbations. The effectiveness of our algorithm is confirmed through simulations in two host movement models, namely random waypoint model (RWM) and seating space model (SSM). This newly presented SSM assumes a seating space of shops, restaurants, and event fields, so that it can simulate more realistic situations.

A License Plate Recognition Algorithm Using Cross Count and Template Matching Methods

Other Link： http://id.nii.ac.jp/1001/00047063/

SHINOHARA Yosuke, FUNABIKI Nobuo, KAWASHIMA Jun, TAKEUCHI Junichi, ISHIZAKI Masayuki

Technical report of IEICE. PRMU 104 ( 573 ) 39 - 44 2005.1

Language：Japanese Publisher：The Institute of Electronics, Information and Communication Engineers

The automatic recognition of characters and numbers on license plates for vehicles is very important for various applications such as vehicle managements in parking lots, automatic fare collections in toll roads, traffic flow measurements and congestion surveillance on roads, and identifications of illegal parking vehicles on streets. In this paper, we propose a license number plate recognition algorithm from digital color images, using the cross count method for character recognitions and the template matching method for number recognitions. Since input images for this algorithm are usually taken in fields manually, and have deformations and effects by shadows, we adopt an adaptive threshold adjustment mechanism for binarization of images in order to deal with undesirable situations. Besides, we introduce an automatic generation method of representative vectors for the cross count method, so that it can handle the increase of complex Chinese characters on license plates. We show that the proposed algorithm provides the 100% success rate for noiseless images taken from an WEB site and the 80% success rate for noisy images taken by a PDA camera.

An Improvement of a Tooth Contour Extraction Method and a Tooth Contour Database Design Based on WEB Applications

SU Tie, FUNABIKI Nobuo, KISHIMOTO Etuo

Technical report of IEICE. PRMU 104 ( 573 ) 31 - 36 2005.1

Language：Japanese Publisher：The Institute of Electronics, Information and Communication Engineers

In recent years, various image-processing technologies have been applied in the field of dentistry, in which, a tooth contour extraction method is strongly expected for the dental treatment and tooth shape classification. At the same time, designing a database based on the extraction result is helpful for the tooth statistical analysis aimed at the clinical treatment. In this paper, a tooth contour extraction method based on deformable template matching is introduced, and its improvement in the automatic threshold adjusting algorithm for cutting gum region around the tooth is proposed. The simulation results using sample images show that the tooth region is separated from the input image by the detected threshold automatically. Then, a tooth contour database design based on WEB applications is proposed to support dental diagnoses. Using the definitions of tooth shape features, the database will be useful in analyzing the difference of tooth shapes according to age, sex, and regions.

A proposal of an access-point allocation algorithm for WDS in wireless LAN

KUMANO Eiji, MITANI Chie, FUNABIKI Nobuo, NAKANISHI Toru

IEICE technical report 104 ( 553 ) 45 - 50 2005.1

Language：Japanese Publisher：The Institute of Electronics, Information and Communication Engineers

A Link Activation Scheduling Algorithm Considering Transmission Success Rates in Packet Radio Networks

TAJIMA Shigeto, FUNABIKI Nobuo, HIGASHINO Teruo

IEICE technical report 104 ( 553 ) 81 - 86 2005.1

Language：Japanese Publisher：The Institute of Electronics, Information and Communication Engineers

A Proposal of a WWW-Based Support System for Class Arrangements to English Teachers (ECASOU)

TAKAHASHI Noriyuki, FUNABIKI Nobuo, YANO Masaaki

The IEICE transactions on information systems Pt. 1 88 ( 1 ) 89 - 98 2005.1

マルチホップ WDM ネットワークにおけるトラヒック分散のための静的トポロジ構成法の改善

木谷友哉, 舩曵信生, 東野輝夫

電子情報通信学会技術研究報告, NS2005-76 2005

Group signature schemes with membership revocation for large groups

T Nakanishi, F Kubooka, N Hamada, N Funabiki

INFORMATION SECURITY AND PRIVACY, PROCEEDINGS 3574 443 - 454 2005

Language：English Publisher：SPRINGER-VERLAG BERLIN

Group signature schemes with membership revocation have been intensively researched. However, signing and/or verification of some existing schemes have computational costs of O(R), where R is the number of revoked members. Existing schemes using a dynamic accumulator or a similar technique have efficient signing and verifications with 0(l) complexity. However, before signing, the signer has to modify his secret key with O(N) or O(R) complexity, where N is the group size. Therefore, for larger groups, signers suffer from enormous costs. On the other hand, an efficient scheme for middle-scale groups with about 1,000 members is previously proposed, where the signer need not modify his secret key. However this scheme also suffers from heavy signing/verification costs for larger groups. In this paper, we adapt the middle-scale scheme to the larger groups. At the sacrifice of the group manager's cost, our signing/verification has only O(1) complexity.

DOI： 10.1093/ietfec/e89-a.5.1275

仮想OSを用いたセキュアなプログラミング課題検証支援システム

長尾憲暁, 舩曵信生, 中西透

電子情報通信学会技術研究報告, ET2005-45 2005

階層型コーダルリングネットワークにおけるコンパクトルーティングアルゴリズム

木谷友哉, 舩曵信生, 東野輝夫

電子情報通信学会技術研究報告, NS2005-145 2005

A proposal of a node configuration algorithm for WDM ring networks

Megumi Isogai, Nobuo Funabiki, Toru Nakanishi, Teruo Higashino

Proc. of International Conference on Optical Communications and Networks (ICOCN-2005) 2005

Compact tree plus algorithms for application-level multicast communications in multihome networks

N Funabiki, M Isogai, T Nakanishi, T Higashino

2005 13TH IEEE INTERNATIONAL CONFERENCE ON NETWORKS JOINTLY HELD WITH THE 2005 7TH IEEE MALAYSIA INTERNATIONAL CONFERENCE ON COMMUNICATIONS, PROCEEDINGS 1 AND 2 139 - 144 2005

Language：English Publisher：IEEE COMPUTER SOC

Application-level multicast (ALM) communications replicate packets on host level to deliver them from a single source to multiple clients, so that it can efficiently realize a variety or network applications using moving pictures such as video conferences, distance learning, and video-on-demands. In this paper, we propose the CT+ (Compact Tree Plus) algorithm for finding a better ALM routing tree in terms of delay minimization between hosts. CT+ consists of a tree construction stage from the existing CT algorithm, and a newly added iterative tree improvement stage. Then, we define the extended ALM routing problem and its heuristic algorithm ExCT+, to optimize the effectiveness of the multihome network in ALM communications by selecting multihomed hosts and connections in the ALM routing tree simultaneously. For their evaluations, we construct a network simulation model named MINET (Multiple-ISP NETwork simulator), where the topology is composed of multiple ISP backbone networks with IX connections, and the network traffic is generated by following the M/M/1 queuing process. The simulation results using MINET verify the effectiveness of our algorithms.

DOI： 10.1109/ICON.2005.1635456

アプリケーションレベルマルチキャスト経路木アルゴリズムCT+法の提案とマルチホーム環境の効果

磯貝愛, 舩曵信生, 中西透

電子情報通信学会論文誌D-Ⅰ 2005

Optical-drop wavelength assignment problem for wavelength reuse in WDM ring metropolitan area networks

N Funabiki, M Isogai, T Nakanishi, T Higashino

19TH INTERNATIONAL CONFERENCE ON ADVANCED INFORMATION NETWORKING AND APPLICATIONS, VOL 1, PROCEEDINGS 999 - 1004 2005

Language：English Publisher：IEEE COMPUTER SOC

This paper presents a formulation of the optical-drop wavelength assignment problem (ODWAP) and its heuristic algorithm for WDM ring networks. The wavelength-division multiplexing (WDM) technology has been popular in communication societies for providing very large communication bands by multiple lightpaths with difterent wavelengths on a single optical fiber Particularly, a double-ring optical network architecture based on the packet-over-WDM technology such as the HORNET architecture, has been studied as a next generation platform for metropolitan area networks (MANs). Each node in this architecture is equipped with a wavelength-fixed optical-drop and a tunable transmitter so that a lightpath can be established between any pair, of nodes without wavelength conversions. In this paper we formulate ODWAP for efficient wavelength reuse under heterogeneous traffic in this network. Then, we propose a simple heuristic algorithm for ODWAP. Through extensive simulations, we demonstrate the effectiveness of our approach in reducing waiting times for packet transmissions when a small number of wavelengths are available to retain the network cost for MANs.

DOI： 10.1109/AINA.2005.267