Browsing by Author "Yuan, SM"

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A component-based, reconfigurable mobile agent system for context-aware computing
(2002)
Chiao, HT
;
Cheng, MC
;
Chang, YS
;
Yuan, SM
;
資訊工程學系
In the near future, people can use various kinds of portable terminal devices, such as PDAs or smart phones, to access,the information on Internet at any time, in any place, for supporting their daily life. Personal mobile agents can help those people to search, to filter, to analyze, or to translate the large amount of Internet information. Since the context of a user may vary frequently, the way a personal mobile agent process the Internet information must adapt to the context change. However, we think that the current mainstream mobile agent platforms, such as the IBM Aglet and the IKV++ Grasshopper, are not good enough for developing context-aware applications. Hence, we propose a Component-based, Reconfigurable Mobile Agent (CRMA) system, which is designed for context-aware computing. It offers downloadable user-interface modules on terminal devices for application to adapt the characteristics of various terminal devices. In addition, on agent side, CRMA provides a reconfigurable agent-programming framework, which uses component-based pipelines to perform context-aware data-processing operations. This not only simplifies the programming task for dynamically reconfiguring an agent's behavior to adapt the context change, but also improves the reusability of agent software. In the end of this paper, we will propose a context-aware meta-search service to demonstrate how to use CRMA to develop a context-aware application.
A fault-tolerant object service in the OMG's object management architecture
(1998-02-01)
Liang, D
;
Chou, SC
;
Yuan, SM
;
資訊工程學系
;
Department of Computer Science
The object management architecture (OMA) has been recognized as a de facto standard in the development of object services in a distributed computing environment. In a distributed system, the provision for failure-recovery is always a vital design issue. However, the fault-tolerant service has not been extensively considered in the current OMA framework, despite the fact that an increasing number of useful common services and common facilities have been adopted in OMA. In this paper, we propose a fault-tolerance developing environment, called Phoinix, which is compatible to the OMA framework. In Phoinix, object services can be developed with embedded fault-tolerance capability to tolerate both hardware and software failures. The fault-tolerance capability in Phoinix is classified into two levels: restart, and rollback-recovery; when the fault-tolerance capability enhances as the level increases. Currently, Phoinix is ported on Orbix 2.0 and on SunOS 4.2. In this paper, the design and implementation of Phoinix is presented and its performance is evaluated. (C) 1998 Elsevier Science B.V.
A fault-tolerant object service in the OMG's object management architecture
(1998-02-01)
Liang, D
;
Chou, SC
;
Yuan, SM
;
資訊工程學系
;
Department of Computer Science
The object management architecture (OMA) has been recognized as a de facto standard in the development of object services in a distributed computing environment. In a distributed system, the provision for failure-recovery is always a vital design issue. However, the fault-tolerant service has not been extensively considered in the current OMA framework, despite the fact that an increasing number of useful common services and common facilities have been adopted in OMA. In this paper, we propose a fault-tolerance developing environment, called Phoinix, which is compatible to the OMA framework. In Phoinix, object services can be developed with embedded fault-tolerance capability to tolerate both hardware and software failures. The fault-tolerance capability in Phoinix is classified into two levels: restart, and rollback-recovery; when the fault-tolerance capability enhances as the level increases. Currently, Phoinix is ported on Orbix 2.0 and on SunOS 4.2. In this paper, the design and implementation of Phoinix is presented and its performance is evaluated. (C) 1998 Elsevier Science B.V.
A fault-tolerant object service on CORBA
(1997)
Sheu, GW
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Chang, YS
;
Liang, DR
;
Yuan, SM
;
Lo, W
There are more and more COSS (Common Object Service Specification) on CORBA (Common Object Request Broker Architecture) that is announced by the OMG (Object Management Group), bur no common specification about fault-tolerance exists now. In this paper, we propose a ''warm stand-by'' replication approach. When an object (primary object) is invoked, it will invoke a secondary object, and the primary object will log the messages and checkpoint the state to the secondary object periodically. If the primary object fails, the secondary object can take over by way of client executing a few operations to change secondary object's mode to primary's. Following the style of COSS, we define four interfaces and provide class implementations that can help programmers write programs with fault-tolerant capability. The whole model has been implemented on Orbix, which is a full implementation of CORBA specification.
A fault-tolerant object service on CORBA
(1999-11-01)
Liang, D
;
Fang, CL
;
Yuan, SM
;
Chen, C
;
Jan, GE
The Common Object Request Broker Architecture (CORBA), is a major industrial standard for distributed object-based applications. Today's large-scale CORBA applications have to deal with object crashes, node failures, networks partitioning and unpredictable communication delays. Existing efforts to enhance the CORBA reliability can be roughly categorized into three approaches: integration approach, interception approach and service approach. Each approach has its own merits and prices. In this paper, we propose a service approach solution called Object Fault-tolerance Service (OFS). Solutions that adopt the service approach usually specify their service in terms of CORBA IDL interfaces. The implementations of such solutions in general do not modify the ORE infrastructure or IDL language mappings, and thus applications developed with those systems appear to be more portable. OFS differs from other service approach solutions in that OFS does not assume underlying support of reliable group communication. Applications with advance registration can rely on OFS for detection of object and node crashes, and for customized recovery. In this paper, we first present the service specification of OFS. We then give the system architecture of an OFS implementation. This OFS implementation is developed on the Solaris 2.5 platform and with IONA's Orbix 2.0. The performance evaluation of the OFS implementation is also presented. The preliminary experiments indicate that OFS overhead is minimal and client objects experience little response delay when a service object is under OFS surveillance. (C) 1999 Elsevier Science Inc. All rights reserved.
A more expressive monitor for concurrent Java programming
(2000)
Chiao, HT
;
Wu, CH
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Yuan, SM
;
資訊工程學系
;
Department of Computer Science
The thread synchronization mechanism employed by Java is derived from the Hoare's monitor concept. In order to minimize its implementation complexity, the monitor provided by Java is quite primitive. This design decision prefers simple concurrent objects and single-thread programs. However, we think the Java monitor is over simplified for developing more elaborated concurrent objects. Besides, several features of the Java monitor will bring extra overhead when thread contention gets higher. Currently, we have identified five drawbacks of the Java monitor. In this paper, we will first analyze these drawbacks in depth, and then propose a new monitor-based synchronization mechanism called EMonior. It has better expressive power, and introduces fewer overheads than the Java monitor when contention occurs. EMonior uses a preprocessor to translate the Java programs containing EMonitor syntax to regular Java programs that invoke EMonitor class libraries. It is very suitable to replace the Java monitor with the EMonitor when developing elaborate concurrent objects or high-contention concurrent systems.
A networked peer assessment system based on a Vee heuristic
(2001-08-01)
Tsai, CC
;
Liu, EZF
;
Lin, SSJ
;
Yuan, SM
;
師資培育中心
This study implements a networked peer assessment system based on the use of a Vee heuristic. Using this system, students submit their homework (relating to designing science activities) via the underlying network facility. They then assess each other's homework by offering suggestions - again, through the network. Students then modify their original designs based on the suggestions that they receive. This procedure is repeated for two or three consecutive rounds. In this process, each student functions as an author, a reviewer, and an adapter. This learning model allows students to further develop their critical thinking skills. Preliminary peer assessment results revealed that the networked peer-assessment model and Vee heuristic facilitated pre-service science teachers to continuously progress when designing science activities.
A new architecture for integration of CORBA and OODB
(1999-09-01)
Sheu, RK
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Liang, KC
;
Yuan, SM
;
Lo, WT
;
資訊工程學系
Object-oriented database system (OODB) supports an object-oriented data model with the functionality of persistency and transaction semantics. In order to facilitate the use of OODB, the Object Database Management Group (ODMG) defined a standard for object database management system. On the other hand, the Object Management Group (OMG) defined the Common Object Request Broker Architecture (CORBA), which is an emerging standard of distributed object technology providing the interconnection network between distributed objects. For the sake of matching these two object models, taking the advantages of merging both of them, and building a more sophisticated infrastructure, the integration of CORBA and OODB is currently an urgent and important issue in distributed object systems. Instead of using Object Database Adapter (ODA) suggested by the ODMG, in this paper, we provide a novel way of reusing the Object Transaction Service (OTS) and wrapping techniques to introduce OODB into CORBA automatically. Through our design, CORBA clients or OODB object implementers do not need to learn any knowledge of each other. In addition, error recovery is also provided to guarantee the consistency of object states. The whole task for integrating CORBA and OODB is done transparently by our proposed preprocessor, which plays an important role in solving problems encountered by ORB and OODB vendors easily.
A new development environment for an event-based distributed system
(2003-08-01)
Hsiao, TY
;
Perng, NC
;
Lo, W
;
Chang, YS
;
Yuan, SM
The rapid growth of data exchange on the Internet has created many critical problems that require an answer. Traditional data exchange systems based on client/server communication models are less scalable and incur especially high maintenance cost in the data exchange domain. For these reasons, many researchers have switched their interest to asynchronous communication models. Although Message-Oriented Middleware (MOM) is a middle-tier infrastructure that links operating systems and applications, such asynchronous communication APIs supported by middleware vendors are usually hard to use. For these reasons, in this study, we present a new development environment for asynchronous communication platforms which we term Ghostwriter. The keyword for our development environment is 'easy', that is, easy to,use, easy to develop, and easy to deploy. Therefore, many researchers have switched their interest to asynchronous communication models. In addition, learning about and implementing the functions of the asynchronous communication's clients in Ghostwriter environment is simple. Other benefits are a lower technical learning curve, help for concentrate on system design, has easily reusable components, and easily integrated applications. (C) 2003 Elsevier Science B.V. All rights reserved.
A new multi-search engine for querying data through an Internet search service on CORBA
(2000-09-01)
Chang, YS
;
Yuan, SM
;
Lo, W
;
資訊工程學系
;
Department of Computer Science
Search engines are important but generally far from ideal tools of the World Wide Web (WWW). Many researchers therefore prefer to use meta-brokers to construct multi-search engines (MSE). However, these have no uniform programming interfaces, which makes tying them with other search engines difficult. Moreover, for an application that needs a search service capability, querying them is difficult. To reduce that difficulty, we propose in this paper an Internet search service (ISS) based on common object request broker architecture (CORBA) that follows the style of common object service specification (COSS). We design a multi-search engine based on ISS, which we term Octopus. For a system developer, because of its uniformity of interface, Octopus easily ties with any search engine. Equally, for an application programmer, the ISS offers a clear interface for application programs to search for information or mine data from the Internet. We demonstrate our approach to designing multi-search engines through ISS by tying two search engine agents, Yahoo and Alta Vista, with Octopus and show how CORBA clients query them. Programmers may use this interface to construct their search engine agents or query a search engine agent in their applications. (C) 2000 Elsevier Science B.V. All rights reserved.
A new quorum-based replica control protocol
(1997)
Wu, YT
;
Chang, YJ
;
Yuan, SM
;
Chang, HK
;
資訊工程學系
Data replication if an important issue in distributed systems. Many protocols are designed to achieve high availability, but some of them have restrictions on N, the number of nodes in the system. This motivates us to design a protocol suitable for arbitrary N. In this paper, we present a new quorum-based replica control protocol whose quorum size is O(root N), which is the same as that of the grid protocol. Moreover; the proposed protocol is almost symmetric, i.e., each node nearly bears the same responsibility. In particular, our protocol performs well in systems where read operations are requested more frequently than write ones.
A pilot study of students' attitudes toward and desired system requirements of networked peer assessment system
(2002)
Lin, SSJ
;
Liu, EZF
;
Yuan, SM
;
交大名義發表
;
National Chiao Tung University
This study applied NetPeas (networked peer assessment system) in peer assessment activities of graduate level of thesis writing course. Authors wish to discover the students' attitudes toward and desired system requirements of NetPeas in writing course. This study involved 100 electrical engineering graduates from two research-oriented universities at northern Taiwan. Those students were required to attend a weekly thesis writing course and submit eight assignments through four rounds of networked peer assessment, and then authors survey their attitudes and opinions toward NetPeas. In the last, quantitative and qualitative surveys indicated that significantly more students willing to join the networked peer assessment activities via NetPeas in the near future and stand for using NetPeas. Authors also have dug several desirable requirements for NetPeas.
A portable real-time extension set for Java
(2001)
Chiao, HT
;
Huang, ST
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Kao, SHJ
;
Yuan, SM
;
資訊工程學系
Since the fourth quarter of 1999, the authors engaged in a project where Java was employed to build the real-time control program inside a plastic-injection-molding machine. However, at that time, since the official real-time Java standard - the Real-Time Specification for Java (RTSJ) from the Sun Microsystems was still under development, no RTSJ-compliant Java virtual machine was available. To satisfy our requirement, we designed and implemented a real-time extension library for enhancing the Java virtual machine that was already available in the real-time operating system we used. Our extension library has the following advantages: First, the underlying Java virtual machine needs no modification to accommodate it. Second, this extension library is easy to be ported to any other priority-based real-time operating systems. Third, the core of this extension library is basically derived from the subset of the RTSJ public draft, and thus our real-time control program can be move to a forthcoming RTSJ-compliant Java virtual machine without much difficulty. In brief, our work may help suggest ways of implementing RTSJ, or the notion of (degrees of) "minimal" compliance/support of RTSJ based on non-RTSJ Java virtual machines. In this paper, we will show the requirement, application programming interface, and implementation of this extension library, and discuss its influence on timing.
A unified interface for integrating information retrieval
(2001-09-01)
Chang, YS
;
Ho, MH
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Yuan, SM
;
資訊工程學系
;
Department of Computer Science
In this paper, we propose a unified interface and a flexible architecture for querying various information sources on the Internet and the WWW using both a popular object model and a data model. We propose an Integrated Information Retrieval MR) service based on the Common Object Service Specification (COSS) for Common Object Request Broker Architecture (CORBA) and apply the Document Type Definition (DTD) of eXtensible Mark-up Language XML) to define the metadata of information sources for sharing the ontology between mediator and wrappers, The objective of using the IIR design is not only to provide programmers with a uniform interface for coding a software application that can query a variety of information sources on the Internet, but also to create a flexible and extensible environment that easily allows system developers to add new or updated wrappers to the system. (C) 2001 Elsevier Science B.V. All rights reserved.
A unified, adjustable, and extractable biological data mining-broker
(2003)
Ho, MH
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Chang, YS
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Cheng, MC
;
Li, KL
;
Yuan, SM
The document formats of biological data sources typically are more versatile and more complicated than the traditional data sources. It is hard to efficiently retrieve useful information from biological data sources by traditional information retrieval technologies. In this paper, we propose a unified, adjustable, and extractable Biological Data Mining-Broker mechanism. Based on XML methodology, the mechanism provides a federated forum model to overcome the heterogeneities of both form and meaning from those different diverse biological data sources. Furthermore, the mechanism also utilizes the feedback-based direct raw and meaningful extracted cache technique to improve the efficiency and accuracy of the system. The experimental results show that our proposed system has good performance, and it is a good choice for biological data mining process with multiple heterogeneous data sources, different mining applications, and knowledge analysts. It is highly useful for target discovery and bioinformatics research projects.
A web-based customized instruction strategy for engineering courses
(2004)
Lin, HT
;
Kuo, TH
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Yuan, SM
;
資訊工程學系
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Department of Computer Science
With the recent establishment of many new universities in Taiwan, it has now become possible for most high school graduates to benefit from higher education. Giving them the widest possible access to the education they need for their careers is a major goal of education administration. In this paper we present a pedagogical approach based on networked dynamic assessment to promote learning performance in the engineering field. Test results are assessed and in the light of any deficiencies revealed, recommendations about suitable learning material for individual needs are made. The focus of this paper is on engineering courses, in particular introductory electronics, and the proposed method of dynamic assessment is specially adapted to take account of the characteristics of engineering courses. The experimental results show that the proposed system has significant effects on the learning process of those participating.
A wrapper generator for integrated information retrieval.
(2002)
Ho, MH
;
Chang, YS
;
Sun, WC
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Yuan, SM
;
資訊工程學系
In the paper, we propose an XML-based framework for automatic wrapper generation.. Different,from the previous approaches, the wrapper generated within this framework is supported to the unified interface for the meta-search information retrieval system based on the Internet Search Service with CORBA standard. Taking advantages of the great compatibilities of CORBA and XML, the user can easily: develop his information gathering application for a. new search engine or any other information source from-the-Internet in a short period. The major contribution of this paper is, to, provide a CORBA and XML compliant solution of wrapper generator supported to unified interface for the information retriever. It is fast, easy and efficient to design a,, uniform-interface-ready wrapper for information retrieval application by the framework presented in,this paper.
An adaptive mobile application development framework
(2005)
Cheng, MC
;
Yuan, SM
;
資訊工程學系
;
Department of Computer Science
Although wireless networks and mobile devices become popular these days, the diversity of mobile devices and unsteadiness of wireless networks still cause software development much trouble. Thus, when developing a mobile application, developers are forced to expose to these problems and to be familiar with these technologies and therefore it will spend a lot of time to write a mobile application. Furthermore, a mobile application often needs to be ported to different platform (for example from Java to .NET) which is also burdensome. In order to overcome these problems, the author proposes an adaptive framework to help developers build mobile application effortlessly and rapidly. The mobile application developed on this framework can run in different devices and operating system, so developers does not need to worry about portability. As a result, a mobile application developed on this framework can enjoy the benefit of "write once, run everywhere, and access any services.".
An asynchronous high confident information interchange infrastructure
(2001)
Hsiao, TY
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Shen, RK
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Liang, KC
;
Perng, NC
;
Yuan, SM
Data exchange by networks is getting important due to the growing of Internet. One of the popular architectural styles for distributed, loosely-coupled, heterogeneous network systems is a structure based on event generation, observation and notification. In this paper, we propose the event-based data exchange model to solve the problems encountered by traditional data exchange systems, We provide two main contributions to the study of data exchange system. First, we cover the surveys of data exchange systems currently on the market as well as the proposed architecture, MEDEA(Model of Event-based Data Exchange Architecture). Second, XML plays an important role in data exchange system now. We also propose a solution, which is called CODEX(Content-Oriented Data EXchange model), combines the features of mark-up language XML and the architecture of MEDEA. CODEX contains functions like primitive data type checking, data classification, data filtering, user identity and user filtering.
An asynchronous message exchange system on CORBA
(2000)
Hsiao, TY
;
Lo, WT
;
Yuan, SM
;
資訊工程學系
;
Department of Computer Science
Data exchange by networks is getting important due to the growing of Internet. One of the popular architectural styles for distributed, loosely-coupled, heterogeneous network systems is a structure based on event generation, observation and notification. Based on the event service and the naming service defined by OMG (Object Management Group), we build an efficient and Internet-scale event-driven data exchange architecture on CORBA. Asynchronous Message Exchange System (AMES) provides asynchronous publish/subscriber communication model and can communicate with legacy systems easily. This system was developed based on Java programming language and Inprise Visibroker for Java product families.