Browsing by Author "Lo, WT"

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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.
An asynchronous message exchange system on CORBA
(2000)
Hsiao, TY
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Lo, WT
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Yuan, SM
;
資訊工程學系
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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.
Integration of CORBA and object relational databases
(2003-08-01)
Liang, KC
;
Chyan, D
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Chang, YS
;
Lo, WT
;
Yuan, SM
CORBA is widely accepted as the open international standard for modelling and building comprehensive distributed systems. In most cases, CORBA architects have adopted relational databases for storage of persistent data. Among the issues that usually face architecture designers considering how to combine CORBA and standard relational database standards are fault tolerance, performance, and the extensibility and scalability of the systems. The research team involved with this paper found that the ODMG object database concept is useful to solve the issues encountered when integrating CORBA and relational database standards. The reference architecture, which the team devises, integrates CORBA and relational databases without compromise on the necessary transactional properties. The CORBA standard object transaction service and concurrency control service are reused. The team also develop an object relational data modelling tool-Latte-that supports the overall design intention as well the development paradigms for the proposed architecture. The implementation of the system is useful to CORBA, ODMG, and relational database architects because it provides a unified modelling and programming paradigm capable of solving the problems of managing mission-critical distributed data. Thus, we present a case study of combining different international standards to build a comprehensive system. (C) 2003 Elsevier Science B.V. All rights reserved.
MEDEA - A model for the event-based data exchange architecture
(2000)
Sheu, RK
;
Yuan, SM
;
Lo, WT
;
資訊工程學系
;
Department of Computer Science
Traditional data interchange mechanisms are based on the client/server model, which has confronted with plethora of problems For example, bilateral partners must exchange data sets through recognized protocols. Whenever the data set is updated, data interchange participants have to rebuild their protocols as well as applications. It is really, a considerable problem for system maintenance or scalability. In this paper, we propose an event-based data exchange model, called MEDE'A, to solve the problems encountered by traditional data exchange systems. The designed MEDEA data exchange framework and the experiences are also detailed.
Object finding system based on RFID technology
(2006)
Chen, LC
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Sheu, RK
;
Lu, HC
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Lo, WT
;
Chu, YP
Locations of moving or missing objects are getting important information for context-aware applications which try to get the locality of an object, and then provide services pertaining to the object. To position an object, most systems use a predefined coordinate to compute object location while sensing the appearance of the target object. Usually, it is troublesome and costs much to define the base coordinate in advance for most object positioning systems, especially when the target object is locating in an unknown environment. To reduce the cost and complexity of object locating system and improve the accuracy of location, this paper proposed an Object Finding System based on RFID technology to identify the localities of target objects in buildings. In this paper, we introduce the design concepts of the proposed system as well as the algorithms used to calculate the object locations. In addition, the experimental results show that it is a feasibility study.