Details of a Researcher - Tokuda, Hideyuki

Papers - Tokuda, Hideyuki

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AMRB: Toward Location Migration Transparency of Services

Noriyuki Harashima,Tadashi Okoshi, Jin Nakazawa, Yoshito Tobe, Hideyuki Tokuda

Proceedings. IEEE International Conference on Parallel and Distributed Systems (ICPADS 2001) 305-312 2001.06

Joint Work, Accepted

In this paper, we present a new mobility-support model for applications, Application Module Request Broker (AMRB). We focus on two types of mobility: host mobility and application code mobility. These two types of mobility dynamically change the binding between applications' name and location in the network. AMRB conceals these changes of binding to reduce a complexity in development of applications. In AMRB, we deal with mobile application codes that communicate with each other as Application Modules (Ams). AMRB provides AM's service transparent communication for applications by using a specifier which does not need to include any network location information. Furthermore, applications can use AM's service transparently of migration by exploiting location management mechanism. In this paper, we describe the design and implementation of AMRB and some evaluations. Also, we demonstrate a sample application that AMRB is effective for developing mobile sensor type applications.

Proceedings. IEEE International Conference on Parallel and Distributed Systems (ICPADS 2001)

Y.Yasuda,N.Nishio, H. Tokuda

IEEE International Workshop on Quality of Service (IWQoS2001)(Lecture Notes in Computer Science Vol.2092) 294-299 2001.06

Joint Work, Accepted

システムソフトウェアの新しい潮流　ASAMA: 適応的なサービス利用管理機構

永田智大,西尾信彦，徳田英幸

情報処理学会論文誌 42 ( 6 ) 1557-1569 2001.06

Joint Work, Accepted

本論文では，周辺のサービスを利用してユーザの要求を実行する超機能分散環境を構築する際に重要となる「サービスの代替利用」と「環境変化の検知」を実現することで，利用可能なサービスが変化してもユーザの要求を継続して実行できる新たなサービスフレームワークを提案し，それを実現する Adaptive Service Availability Management システム (ASAMA) のプロトタイプを実装し，評価を行った． ASAMA は，サービスイニシエータ，サービスプロバイダ，ディレクトリサーバの 3 つのエンティティから構成される．PDA やノート PC などのサービスイニシエータは，装備する資源が貧弱なため，周辺のサービスプロバイダからサービスを提供してもらい，必要な機能を補完する． ASAMA ではサービスを入出力によって定義し，段階的なサービスの検索を行うため，代替可能なサービスも発見でき，メディアデータのやりとりでサービスを利用できる．また，環境変化をサービスイニシエータの物理的移動による能動的環境変化と，サービスプロバイダの起動・終了によって生じる受動的環境変化に分類し，これらを透過的に検知し，より品質の高いサービスに切り替えられる．本論文では，本プロトタイプを典型的な超機能分散環境下で実際に動作させ，目的を実現できるか，実証実験を行い，その利便性を示した．また，各処理に要する時間や受動的環境変化検知に関するネットワークトラフィックを測定し， ASAMA の基本性能を評価した．

システムソフトウェアの新しい潮流　QOSプロファイルハンドラつき資源予約機構の設計と実装

西尾信彦，徳田英幸

情報処理学会論文誌 42 ( 6 ) 1570-1579 2001.06

Joint Work, Accepted

よりpredictableな計算機環境を構築するために，計算機資源の予約は必須であるが，アプリケーションプログラマからは予約すべき資源量の算定が容易ではないうえに，それが通常は動的に変動してしまうために必ずしも利用は容易ではない．本稿では，従来の資源予約オブジェクトごとにQOSプロファイルハンドラを生成することにより，適切な資源量の見積りを動的に実施し，さらに動的な処理内容やシステム状況の変化への適応性を高めることを目標とした統合的資源管理機構の設計と実装について報告する．本実装は，OS内の低レベル資源予約管理と資源予約調停および翻訳のための資源予約管理サーバ，QOSプロファイルハンドラと動的適応するための非同期イベントメッセージを受信するポートを備えたライブラリにより構成し，GUIインタフェースをサーバに与えることにより，よりユーザに明解で抽象度の高いプログラミング環境を提供することができた．

Improvised Assembly Mechanism for Component-Based Mobile Applications

M.Mochizuki, H. Tokuda

((IEICE Transaction on Communications)) E84-B ( 4 ) 910-919 2001.04

Joint Work, Accepted

We propose a mechanism to facilitate the development of component-based mobile applications with adaptive behaviors. The design principles and communication patterns of legacy software systems will greatly change in a forthcoming environment, where a variety of computing devices become embedded in home and office environments, users move around with/without portable computing devices, and all the devices are interconnected through wired/wireless networks. In the proposed mechanism, Improvised Assembly Mechanism (IAM), we realize functionality to compose an application in an ad hoc manner and to achieve the adaptation of applications by adding, replacing, supplementing, and relocating components at system runtime according to various environmental changes such as the locational changes of computing devices and users. The mechanism is implemented as a built-in functionality of the Soul component, which is one of the fundamental elements in the Possession model.

A Mobile Agent Framework for Follow-Me Applications in Ubiquitous Computing Environment

Kazunori Takashio,Gakuya Soeda, Hideyuki Tokuda

Proceedings 21st International Conference on Distributed Computing System Workshop 202-207 2001.04

Joint Work, Accepted

The work described a personal corner and desk-top manager. The PDA device stored the keys, passphrases and location information. This follow-me feature was achieved through a secure call-up protocol. The environmental awareness were imported into the application as marshalled environment events. The environmental awareness provided the basis for QoS adaptation. Internal metrics include display size, CPU and memory, and locale information. External metrics include power service, and evaluation service. The call-up would go back to the previous machine to retrieve the standby agents. The Java applications were suspended by flushing their state to the machine (which might compromise the security model). Research issued identified include policy negotiation, QoS adaptation, and resource policy.

A Location-Adaptive Virtual Networked Appliance

A.Kusumoto, J.Nakazawa, Y.Tobe, H. Tokuda

Proceedings 21st International Conference on Distributed Computing System Workshop 214-219 2001.04

Joint Work, Accepted

This work explored location-based virtual plug-and-play. It allowed functional manipulation of objects through the run-time for applications (known as Serdget). A mark-up language (VML) described the functional components of virtual networked appliances (VNA). Some issued include dynamic locations, adaptation, wireless mobile devices, and heterogeneous network. Devices were represented with some structure indicating who else were in the same location. The devices themselves were decentralised. The location mapping mechanism provided lookup, registrar, location update, and event notification. The mechanism addressed issues pertaining to its overhead, modularity of search and autonomy. The area manager appears to be hierarchical rather than peers, which imposed total ordering and partial ordering respectively.

Smart Space Laboratory Project: Toward the Next Generation Computing Environment

T.Okoshi,S.wakayama, Y.Sugita, S.Aoki, T.Iwamoto, J.Nakazawa, D.Furusaka, M.Iwai, A.Kusumoto, N.Harashima, J.Yura, N.Nishio, Y.Tobe, Y.Ikeda, H.Tokuda

IEEE International Workshop on Networked Appliances(IWNA) 2001.03

Joint Work, Accepted

This paper describes the Smart Space Lab (SSLab) project toward the next generation computing environment, ``{sf Smart Space}.'' As numerous types of networked appliances, such as A/V devices, home appliances, or sensors, are connected to each other via both wired and wireless networks, computational intelligence can be regarded as being distributed and embedded into users' surrounding space, rather than on a specific device such as users' PCs or PDAs. We call such a space with embedded computation ``Smart Space.'' In Smart Space, users can have their computing environment relying on not only computation of their carrying devices, but one in Smart Space. Toward the realization of Smart Space, SSLab Project is now addressing three research issues, (A)physical structure of Smart Space, (B)network architecture with support of dynamism and heterogeneity, and cadaptive middleware architecture and applications.

An Application Framework for Wearable Network Computing

T.Iwamoto, N.Nishio, H. Tokuda

IEEE International Workshop on Networked Appliances(IWNA) 2001.03

Joint Work, Accepted

Today, new computing environment called wearable computing is getting popular in research. However, many of these research issues are mainly focused on the user interface or the miniaturization of PC platform. These hardware related researches may achieve some results, however these researches do not present an application and a software organization that are suitable and needed for wearable computing environment.We propose wearable computing environment named `` Wearable Network computing'' which supports cooperation of many devices and appliances around user's body. In {it Wearable Network} computing environment, the application may be distributed into various devices and appliances around user's body and accomplish user's task by using the function of these devices. In this environment the wearable computer controls the distributed application adapting to changes of user's context and to availability of devices.In this paper, we describe the an applicaton framwork for wearable computing environment which may provide context-awareness, device coordination, distributed and migratable application.

Adaptive Service Availability Management Mechanism for Wearable Network Computing

T.Nagata, N.Nishio, H.Tokuda

IEEE International Workshop on Networked Appliances(IWNA) 2001.03

Joint Work, Accepted

A Top-down Integration Scheme for Networked Appliances using VNA Markup Language

Jin Nakazawa,Tadashi Okoshi, Yoshito Tobe, Hideyuki Tokuda

IEEE International Workshop on Networked Appliances(IWNA) 96-101 2001.03

Joint Work, Accepted

This paper presents a new middleware architecture for integrating heterogeneous information appliances on heterogeneous network for various users, called Virtual Network Appliance (VNA) Architecture. Instead of merely connecting appliances seen in existing approaches, VNA architecture accommodates creating a function alliance called a VNA. VNA Markup Language is our solution to define VNAs independent of specific home networks. Our middleware enables users not only to define VNAs by themselves (bottom-up integration), but also to virtually plug and play pre-defined VNAs (top-down integration).

SONA: Applying Mobile Agent to Networked Appliance Control

Soko Aoki, Satoshi Makino, Jin Nakazawa,Tadashi Okosh, Hideyuki Tokuda

IEEE International Workshop on Networked Appliances(IWNA) 78-83 2001.03

Joint Work, Accepted

This paper proposes Smart Operation of Networked Appliances (SONA) system, a new control system for networked appliances using mobile agents. By adopting mobile agents to the control system, the SONA system can control networked appliances autonomously and asynchronously. This can relieve users from direct and complicated operations of the appliances. In addition, the SONA system facilitates the control of networked appliances with limited system resources. In this paper, we present the design and implementation of SONA system.

An Application Framework for Wearable Network Computing

T.Iwamoto, N.Nishio, H. Tokuda

IEEE International Workshop on Networked Appliances(IWNA) 2000.12

Joint Work, Accepted

Dragon: Soft Real-Time Event Delivering Architecture for Networked Sensors and Appliances

Masayuki Iwai,Jin Nakazawa, Tokuda H

Proceedings IEEE The 7th International Conference on Real-Time Computing System and Applications 425-432 2000.12

Joint Work, Accepted

This paper presents a new framework for constructing flexible event-driven systems for distributed networked devices and appliances, referred to as Dragon. Dragon enables constructing and modifying an event-driven system easily by visualizing distributed services which are handled in an integrated manner. The update of the system is conducted immediately following a modification by Dragon. Dragon is built on to of Jini/Java and can be executed on any Jini/Java-compliant machines. In addition, Dragon incorporates soft real-time event delivery to enhance the predictability of behavior of the constructed system. In this paper, we describe in detail of design and implementation of Dragon.

Wearable Network: Architecture and Implementation

N.Nishio,T.Iwamoto, T.Nagata, H.Tokuda

IEEE International Workshop on Networked Appliances(IWNA) 2000.12

Joint Work, Accepted

Today, Wearable Computers are popular in research, however, they are dedicated almost for methods of human interface design. We do not expect WC's as a merely super-compact notebook computer or its extension, which includes everything and runs the same OS as desktop PC's do. Meanwhile, short-range radio-networking technology as Bluetooth, is emerging. We envision that a WC plays a role as a control center which conducts and collaborates with the devices or gadgets also worn by a person in response to the environmental changes. All these appliances should be networked in any way, and a person does not wear appliances but rather the network itself. We named it as wearable network, and are constructing the software architecture for this. This article describes the wearable network architecture, from the device layer, which captures and collects raw data of evironmental information around the owner, a database module which consists of the knowledge on the real-world and the owner's intention, to the application layer, which enables the adaptable coordination among the services timely available. We also explain a current state-of-the-art wearable network implementation.

Achieving Moderate Fairness for UDP Flows by Path-Status Classification

Yoshito Tobe,Yosuke Tamura, Anastasio Molano, Sourav Ghosh, Hideyuki Tokuda

Proceedings 25th Annual IEEEConference on Local Computer Network. (LCN2000) 252-261 2000.11

Joint Work, Accepted

Wireless Packet Scheduling with Signal-to-Noise Ratio Monitoring

H. Aida,Y. Tamura, Y. Tobe, H. Tokuda

Proceedings 25th Annual IEEEConference on Local Computer Network. (LCN2000) 32-41 2000.11

Joint Work, Accepted

A key challenge in packet scheduling over a wireless channel is to achieve effective throughput against bursty errors. Although there have been several proposals on packet scheduling for a wireless channel, they are only based on bi-modal channel states: good or bad. In this paper we propose a new packet scheduling scheme for wireless links based on the receiver's signal to noise ratio (SNR). The scheme is referred to as SNR-based packet scheduling (SPS). In SPS, outgoing packet flows are scheduled such that the flows with higher SNR values have larger weights in scheduling. SPS can achieve effectiveness by adopting a flexible mapping between weight and SNR. We present measured results of the relationship between throughput and SNR as well as the design and implementation of SPS. In our experiments, SPS has shown its effectiveness in enhancing total throughput for hosts with good and bad wireless connectivity over a wireless LAN.

ポゼッションウェア：「間に合わせ」手法によるアプリケーション構成ツールキット

望月祐洋，徳田英幸

日本ソフトウェア科学会論文誌コンピュータソフトウェア 17 ( 6 ) 521-533 2000.06

Joint Work, Accepted

本論文では，「間に合わせ」手法に基づいてアプリケーションの動的構成を支援するためのツールキットであるポゼッションウェアの設計・実装について述べる．ポゼッションウェアは，遍在するデバイスやソフトウェア部品を抽象化したBodyコンポーネントと，それらを統合してアプリケーションを構成する実体であるSoulコンポーネント，および基盤システムから成る．Soulコンポーネントが，基盤システムを通じてディレクトリサービスやコンポーネントレポジトリと通信することで，ユーザの近隣に遍在する部品を探索・選択し，アプリケーションを動的に構成する．本論文では，ポゼッションウェアにおけるアプリケーション構成の基本となる「間に合わせ」手法について述べ，本手法に基づくアプリケーション構成例のいくつかを応用事例として示す．

VNA: An Object Model for Virtual Network Appliances

Jin Nakazawa,Tadashi Okoshi, Masahiro Mochizuki, Yoshito Tobe, Hideyuki Tokuda

2000 Digest of Technical Papers. IEEE International Conference on Consumer Electronics (ICCE2000) 2000.06

Joint Work, Accepted

SF-FC: A Neighbor-State Based Flow Control with Soft Fairness

Y.Tamura,Y.Tobe

The 10th International Workshop on Network and Operating System Support for Digital Audio and Video(NOSSDAV) 2000.06

Joint Work, Accepted

Many audio and video stream applications in the Internet require good network performance but not perfect reliability. Such applications should employ congestion control and should not shut down the TCP flows by restricting buffering too much. However, the Internet is not a small local community, and it is impossible to rely on all developers to incorporate end-to-end congestion control in their Internet applications. The network should take part in controlling its own resource utilization. Most research for fair queuing tend to focus on reducing processing overhead and achieving exact fairness for each flow. In this paper we claim that perfect fair queuing is not effective for end users in the current complicated network environment. We propose Soft Fair Flow Control(SF-FC) which is a light weight router mechanism that employs simple FIFO queuing, and shows high performance than other fair queuing. SF-FC provides fair network resource allocation to non-adaptive and adaptive flows. Each SF-FC router informs the upstream SF-FC router of its link state. Based on the received state, SF-FC dynamically sets the packet discard rate of the non-adaptive flows. '

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