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2341-2360hit(3578hit)

  • An End-to-End Network Architecture for Supporting Mobility in Wide Area Wireless Networks

    Riaz INAYAT  Reiji AIBARA  Kouji NISHIMURA  Takahiro FUJITA  Kaori MAEDA  

     
    PAPER-Network

      Vol:
    E87-B No:6
      Page(s):
    1584-1593

    This paper presents a network architecture with a dual interface IP handoff technique that allows smooth node mobility without using any intermediate proxy. The proposed architecture is suitable for low bit-rate time sensitive real time applications, where payload tends to be short and packet header overhead is particularly significant. Connections are established as per permanent addresses of the nodes but are carried on by the IP layer according to the temporary addresses by address translation within the end hosts. The mapping information is maintained by database servers, which can be placed in the Internet in a distributed manner. We describe the architecture and show its mobile capabilities by prototype implementation and performance evaluation. Furthermore a dual-interface handoff suitable to the proposed architecture is also introduced. Preliminary results show that the proposed architecture has significantly low overheads. It is compatible with the existing infrastructure and works fine in both IPv4 and IPv6 environments. Analysis also shows that with dual-interface handoff it is possible to achieve seamless handoff without any packet loss by exploiting overlapping coverage area and speed of the mobile node. Handoff latency is reduced significantly as compare to MIPv6. We believe that with more powerful network interface card drivers our concept of dual interface handoff can be realized.

  • Bottles: A Transparent Interface as a Tribute to Mark Weiser

    Hiroshi ISHII  

     
    INVITED PAPER

      Vol:
    E87-D No:6
      Page(s):
    1299-1311

    This paper first discusses the misinterpretation of the concept of "ubiquitous computing" that Mark Weiser originally proposed in 1991. Weiser's main message was not the ubiquity of computers, but the transparency of interface that determines users' perception of digital technologies embedded in our physical environment seamlessly. To explore Weiser's philosophy of transparency in interfaces, this paper presents the design of an interface that uses glass bottles as "containers" and "controls" for digital information. The metaphor is a perfume bottle: Instead of scent, the bottles have been filled with music -- classical, jazz, and techno music. Opening each bottle releases the sound of a specific instrument accompanied by dynamic colored light. Physical manipulation of the bottles -- opening and closing -- is the primary mode of interaction for controlling their musical contents. The bottles illustrates Mark Weiser's vision of the transparent (or invisible) interface that weaves itself into the fabric of everyday life. The bottles also exploits the emotional aspects of glass bottles that are tangible and visual, and evoke the smell of perfume and the taste of exotic beverages. This paper describes the design goals of the bottle interface, the arrangement of musical content, the implementation of the wireless electromagnetic tag technology, and the feedback from users who have played with the system.

  • A Workflow Enactment Model for Next Generation Internet Services

    Lee-Sub LEE  Soo-Hyun PARK  Doo-Kwon BAIK  

     
    PAPER

      Vol:
    E87-A No:6
      Page(s):
    1463-1471

    Providing workflow function is one of the most important research issues in the next generation Internet services such as Web Service and Grid Computing. Scalability for Internet scale services, reliability for unstable Internet resources, and management functions of workflow systems are the essential requirements in these environments. However, existing workflow enactment models for enterprises could not meet these requirements. This paper proposes the PeerFlow that is a P2P based workflow enactment model, to provide workflow functions for the next generation Internet services. To apply P2P model to the workflow enactment model, we introduce the concept of the instance buddy and the index data of workflow instances, then propose the principle architecture of the PeerFlow. The instance buddy enables the autonomous processing of peers, and it is used for recovery and monitoring functions. This paper also presents the recovery capabilities of PeerFlow with formal proofs for the reliability issues and a performance evaluation with SimPy, the Python simulation package.

  • Partition Timing Routing Protocol in Wireless Ad Hoc Networks

    Jen-Yi HUANG  Hsi-Han CHEN  Lung-Jen WANG  Chung-Hsien LIN  Wen-Shyong HSIEH  

     
    PAPER

      Vol:
    E87-D No:6
      Page(s):
    1433-1437

    Ad Hoc Networks are transmission networks in the structure of wireless networks that consist of many mobile hosts. They do so without the support from other communication infrastructures like Base Stations, and directly use wireless networks for data-transmission. This paper provides a general explanation of related protocols for setting up routes and their possible problems. In addition, related researches are described with their method of solving problems and reducing the possibility of problems occurring. Then, a novel constructive protocol called Partition-Timing Routing Protocol (PTR) is presented. If any covered node needs to transmit data to others outside the scope, it has to be managed by a core node. This protocol is able to adjust neighboring nodes covered in the scope, to select certain nodes to be their own core node. In addition, the timing for updating and adjusting the data of the covered scope is different from other methods, and at the same time it reduces the load of the entire network and makes it more flexible.

  • A Versatile Broadcasting Algorithm on Multi-Hop Wireless Networks: WDD Algorithm

    Toshio KOIDE  Hitoshi WATANABE  

     
    PAPER-Mobile Information Network and Personal Communications

      Vol:
    E87-A No:6
      Page(s):
    1599-1611

    In recent years, studies on multi-hop wireless networks have been made by many brilliant researchers. Such a network consists of a set of mobile nodes having wireless communication devices, and is constructed by the nodes autonomously. The most serious problem on the network is the difficulty of network topology management. All nodes are freely movable and their topology is dynamically changing continuously, so it is difficult to determine the paths to any nodes in the network. Although a classical flooding algorithm is a robust algorithm in that situation, the number of retransmitting nodes increases beyond what is necessary. In this paper, a new and more efficient information dissemination algorithm called WDD is proposed, which can substitute for various broadcasting algorithms by just selecting an appropriate waiting-time function. The algorithm is implemented and its applicability is evaluated on a network simulator.

  • A Timing Driven Crosstalk Optimizer for Gridded Channel Routing

    Shih-Hsu HUANG  Yi-Siang HSU  Chiu-Cheng LIN  

     
    LETTER-Computer Components

      Vol:
    E87-D No:6
      Page(s):
    1575-1581

    The relative window method provides quantitative crosstalk delay degradation for the post-layout timing analysis in deep sub-micron VLSI design. However, to the best of our knowledge, the relative window method has not been applied to the crosstalk minimization in gridded channel routing problem. Most conventional crosstalk optimizers only use the coupling length to estimate the crosstalk. In this paper, we present a post-layout timing driven crosstalk optimizer based on the relative window method. According to the relative signal arrival time and the coupling length, we define a delay degradation graph to describe the crosstalks between nets in a routing solution. Our optimization goal is to maximize the time slack by iteratively improving the delay degradation graph without increasing the channel height. Benchmark data consistently show that our post-layout timing driven crosstalk optimizer can further improve the routing solution obtained by a conventional crosstalk optimizer.

  • Threshold Voltage Mismatch of FD-SOI MOSFETs

    Yoshiyuki SHIMIZU  Toshimasa MATSUOKA  Kenji TANIGUCHI  

     
    LETTER

      Vol:
    E87-C No:6
      Page(s):
    1013-1014

    The threshold voltage mismatch of FD (Fully depleted) SOI (Silicon on insulator) devices have been studied. Floating body MOSFETs operating at high drain voltage show a large mismatch in the threshold voltage compared with body-tied MOSFETs. Those experimental data under different drain voltages indicate that both floating body effect and DIBL (Drain induced barrier lowering) are involved in the threshold voltage mismatch of floating body MOSFETs.

  • Improving TCP Performance over ATM-UBR with FED+ Scheme

    YoonTze CHIN  Shiro HANDA  Fumihito SASAMORI  Shinjiro OSHITA  

     
    PAPER-Switching

      Vol:
    E87-B No:6
      Page(s):
    1514-1523

    We had previously proposed a fuzzy logic-based buffer management scheme (BMS) called fuzzy early detection (FED), which was designed to improve transmission control protocol (TCP) performance over the unspecified bit rate (UBR) service of asynchronous transfer mode (ATM) networks. Since a weakness in FED was discovered later, we present a refined version of it named FED+ here. Maintaining the design architecture and the algorithm of FED, FED+ further adopts a specific per virtual connection accounting algorithm to achieve its design goals. The effects of TCP implementation, TCP maximum segment size, switch buffer size and network propagation delay on FED+ performance are studied through simulation. Its performance is then compared with those of pure early packet discard (EPD), P-random early detection (P-RED) and FED. Our evaluations show that FED+ is superior to the others if the issues of efficiency, fairness, robustness, buffer requirement and the ease of tuning control parameters of a BMS are considered collectively.

  • Reduction of Sound Localization Error for Non-individualized HRTF by Directional Weighting Function

    Sin-Lyul LEE  Lae-Hoon KIM  Koeng-Mo SUNG  

     
    PAPER-Engineering Acoustics

      Vol:
    E87-A No:6
      Page(s):
    1531-1536

    The non-individualized head related transfer function (HRTF) is known to have a few problems, which are referred to as the 'hole in the middle' phenomenon and 'front-back reversals.' To overcome these problems, an HRTF refinement technique was introduced, but unfortunately, this refinement technique causes sudden degradation in sound quality and difficulty in cross-talk cancellation because of notch frequency exaggeration. In this paper, an HRTF refinement using directional weighting function is proposed. This newly proposed technique weights ordinary HRTF according to its direction to amplify frontal sound intensity. Since the proposed technique does not exaggerate the notch frequency, spectral differences in the 'cone-of-confusion' region become more pronounced within overall audible frequencies, resulting in mitigating the sound degradation. In addition, the cross-talk cancellation can be done more easily. We verified the superiority of the proposed technique over the existing one by means of the sound localization and sound quality tests in headphone and loudspeakers.

  • A Distributed Parallel Genetic Local Search with Tree-Based Migration on Irregular Network Topologies

    Yiyuan GONG  Morikazu NAKAMURA  Takashi MATSUMURA  Kenji ONAGA  

     
    PAPER

      Vol:
    E87-A No:6
      Page(s):
    1377-1385

    In this paper we propose a parallel and distributed computation of genetic local search with irregular topology in distributed environments. The scheme we propose in this paper is implemented with a tree topology established on an irregular network where each computing element carries out genetic local search on its own chromosome set and communicates with its parent when the best solution of each generation is updated. We evaluate the proposed algorithm by a simulation system implemented on a PC-cluster. We test our algorithm on four types topologies: star, line, balanced binary tree and sided binary tree, and investigate the influence of communication topology and delay on the evolution process.

  • Performance Evaluation of Dynamic Multi-Layer Routing Schemes in Optical IP Networks

    Eiji OKI  Kohei SHIOMOTO  Masaru KATAYAMA  Wataru IMAJUKU  Naoaki YAMANAKA  Yoshihiro TAKIGAWA  

     
    PAPER-Network

      Vol:
    E87-B No:6
      Page(s):
    1577-1583

    This paper presents two dynamic multi-layer routing policies for optical IP Networks. Both policies first try to allocate a newly requested electrical path to an existing optical path that directly connects the source and destination nodes. If such a path is not available, the two policies employ different procedures. Policy 1, which has been published already, tries to find available existing optical paths with two or more hops that connect the source and destination nodes. Policy 2, which is proposed in this paper, tries to establish a new one-hop optical path between source and destination nodes. The performances of the two routing policies are evaluated. Simulation results suggest that policy 2 outperforms policy 1 if p is large, where p is the number of packet-switching-capable ports; the reverse is true only if p is small. We observe that p is the key factor in choosing the most appropriate routing policy.

  • LifeMinder: A Wearable Healthcare Support System with Timely Instruction Based on the User's Context

    Kazushige OUCHI  Takuji SUZUKI  Miwako DOI  

     
    PAPER

      Vol:
    E87-D No:6
      Page(s):
    1361-1369

    Management of diet and exercise is especially significant in preventing "lifestyle-related diseases" for patients and subclinical cases. This paper introduces a questionnaire survey on diabetic regimens that targets 38 professional users such as physicians and nurses at a diabetic clinic. Based on the results of the questionnaire survey, a design concept for a wearable healthcare support system has been developed to provide patients with timely instruction in accordance with their current context. On the basis of this design concept, we developed a prototype of a wearable healthcare support system called "LifeMinder". "LifeMinder" is composed of a wristwatch-shaped wearable sensor module and a personal digital assistant (PDA). The sensor module measures 3-axis acceleration, pulse rate, galvanic skin reflex (GSR), and skin temperature. The PDA receives this data via BluetoothTM and recognizes the patient's general behavior such as "walking" or "eating". The recognition of these behaviors reduces the patient's mental and physical burden in daily healthcare and assists in support of medical treatment.

  • Reflection Routing: A Simple Approach for Contention Resolution in All-Optical Packet Switched Networks

    Hiroyuki YOKOYAMA  Hajime NAKAMURA  Shinichi NOMOTO  

     
    PAPER-Network

      Vol:
    E87-B No:6
      Page(s):
    1561-1568

    Packet loss is a serious problem due to the shortage of optical buffers in all-optical packet switched networks. In order to reduce packet losses, a dynamic routing method called 'deflection routing' has been proposed. Deflection routing, however, requires an optical switch to modify routing tables and packet labels for overflowing packets, so this routing method may also lead to other implementation problems in packet routing and forwarding. This paper proposes a simple routing method called 'reflection routing' which utilizes optical transport links as optical buffers to improve the quality of service in optical packet switched networks in terms of packet loss ratio. We numerically demonstrate the effectiveness and applicability of reflection routing.

  • QoS-Guaranteed Wavelength Allocation for WDM Networks with Limited-Range Wavelength Conversion

    Takuji TACHIBANA  Shoji KASAHARA  

     
    PAPER-Fiber-Optic Transmission

      Vol:
    E87-B No:6
      Page(s):
    1439-1450

    In this paper, we consider QoS-guaranteed wavelength allocation for WDM networks with limited-range wavelength conversion. In the wavelength allocation, the pre-determined number of wavelengths are allocated to each QoS class depending on the required loss probability. Moreover, we consider two wavelength selection rules and three combinations of the rules. We analyze the connection loss probability of each QoS class for a single link using continuous-time Markov chain. We also investigate the connection loss probability for a uni-directional ring network by simulation. In numerical examples, we compare connection loss probabilities for three combinations of selection rules and show how each combination of selection rules affects the connection loss probability of each QoS class. Furthermore, we show how wavelength conversion capability affects the connection loss probability. It is shown that the proposed allocation with appropriate wavelength selection rule is effective for QoS provisioning when the number of wavelengths is large. We also show the effective combination of wavelength selection rules for the case with small wavelength conversion capability.

  • Robotic Hand System for Non-verbal Communication

    Kiyoshi HOSHINO  Ichiro KAWABUCHI  

     
    PAPER

      Vol:
    E87-D No:6
      Page(s):
    1347-1353

    The purpose of this study is to design a humanoid robotic hand system that is capable of conveying feelings and sensitivities by finger movement for the non-verbal communication between men and robots in the near future. In this paper, studies have been made in four steps. First, a small-sized and light-weight robotic hand was developed to be used as the humanoid according to the concept of extracting required minimum motor functions and implementing them to the robot. Second, basic characteristics of the movement were checked by experiments, simple feedforward control mechanism was designed based on velocity control, and a system capable of tracking joint time-series change command with arbitrary pattern input was realized. Third, tracking performances with regard to sinusoidal input with different frequencies were studied for evaluation of the system thus realized, and space- and time-related accuracy were investigated. Fourth, the sign language motions were generated as examples of information transmission by finger movement. A series of results thus obtained indicated that this robotic hand is capable of transmitting information promptly with comparatively high accuracy through the movement.

  • Loss Probability Evaluation of Reforwarding Call-Terminating Messages

    Yoshiaki SHIKATA  Yoshitaka TAKAHASHI  

     
    PAPER-Mobility Management

      Vol:
    E87-B No:5
      Page(s):
    1151-1157

    In a telecommunication network system, a scheme for reforwarding call-terminating setup messages (SETUP messages) is used to guard against their loss. We have developed a method for evaluating the loss probability of these reforwarding schemes. We started with a stochastic model in which the messages are reforwarded after a constant time span from the time that the first messages have been forwarded. This model corresponds to the finite-capacity BPP/M/1/m model. We showed a method for calculating the "timeout" probability. We then added an approximate method for calculating the loss probability. Finally, using the proposed methods, we clarified the existence of the best reforwarding timelag.

  • Exploiting the Difference in Probability Calculation between Quantum and Probabilistic Computations

    Masami AMANO  Kazuo IWAMA  Raymond H. PUTRA  

     
    PAPER

      Vol:
    E87-A No:5
      Page(s):
    1004-1011

    The main purpose of this paper is to show that we can exploit the difference (l1-norm and l2-norm) in the probability calculation between quantum and probabilistic computations to claim the difference in their space efficiencies. It is shown that there is a finite language L which contains sentences of length up to O(nc+1) such that: (i) There is a one-way quantum finite automaton (qfa) of O(nc+4) states which recognizes L. (ii) However, if we try to simulate this qfa by a probabilistic finite automaton (pfa) using the same algorithm, then it needs Ω(n2c+4) states. It should be noted that we do not prove real lower bounds for pfa's but show that if pfa's and qfa's use exactly the same algorithm, then qfa's need much less states.

  • Negation as Failure through a Network

    Kazunori IRIYA  Susumu YAMASAKI  

     
    PAPER-Computation and Computational Models

      Vol:
    E87-D No:5
      Page(s):
    1200-1207

    This paper deals with distributed procedures, caused by negation as failure through a network, where general logic programs are distributed so that they communicate with each other in terms of negation as failure inquiries and responses, but not in terms of derivations of SLD resolutions. The common variables as channels in share for distributed programs are not treated, but negation as failure validated in the whole network is the object for communications of distributed programs. We can define the semantics for the distributed programs in a network. At the same time, we have distributed proof procedures for distributed programs, by means of negation as failure to be implemented through the network, where the soundness of the procedure is guaranteed by the defined semantics.

  • Some Relations between Watson-Crick Finite Automata and Chomsky Hierarchy

    Sadaki HIROSE  Kunifumi TSUDA  Yasuhiro OGOSHI  Haruhiko KIMURA  

     
    LETTER-Automata and Formal Language Theory

      Vol:
    E87-D No:5
      Page(s):
    1261-1264

    Watson-Crick automata, recently introduced in, are new types of automata in the DNA computing framework, working on tapes which are double stranded sequences of symbols related by a complementarity relation, similar to a DNA molecule. The automata scan separately each of the two strands in a corelated mannar. Some restricted variants of them were also introduced and the relationship between the families of languages recognized by them were investigated in. In this paper, we clarify some relations between the families of languages recognized by the restricted variants of Watson-Crick finite automata and the families in the Chomsky hierarchy.

  • Recognition of Continuous Korean Sign Language Using Gesture Tension Model and Soft Computing Technique

    Jung-Bae KIM  Zeungnam BIEN  

     
    LETTER-Human-computer Interaction

      Vol:
    E87-D No:5
      Page(s):
    1265-1270

    We present a method for recognition of continuous Korean Sign Language (KSL). In the paper, we consider the segmentation problem of a continuous hand motion pattern in KSL. For this, we first extract sign sentences by removing linking gestures between sign sentences. We use a gesture tension model and fuzzy partitioning. Then, each sign sentence is disassembled into a set of elementary motions (EMs) according to its geometric pattern. The hidden Markov model is adopted to classify the segmented individual EMs.

2341-2360hit(3578hit)