• 한국정보시스템학회지:정보시스템연구
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• 제4권
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• pp.85-104
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• 1995

In a loosely-coupled distributed database server system, a server failure and/or a communication failure can be masked by a resiliency mechanism. Recognizing that a distributed transaction executes at several servers during its lifetime, we propose a resiliency mechanism which allows continuous transaction processing in distributed database server systems in the presence of a server failure. The resiliency mechanism for transaction processing is achieved by keeping redundant information using a primary/backup approach. The purpose of this paper is to analyze the performance improvement opportunities with the resiliency mechanism and to present the design of the proposed system.

• Asia pacific journal of information systems
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• 제7권3호
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• pp.23-37
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• 1997

Although numerous models and solution algorithms to design efficient distributed databases have been developed, very few have been validated for their effectiveness. In this paper, we develop a simulation system which can be used to analyze and validate the average response time of distributed database designs. Our simulation system models comprehensive query processing strategies such as semijoin as well as a concurrency control mechanism We analyze and validate an average response time distributed database design model using our simulation system.

• 인터넷정보학회논문지
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• 제18권6호
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• pp.47-53
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• 2017

Recently, huge datasets have been generating rapidly in a variety of fields. Then, there is an urgent need for technologies that will allow efficient and effective processing of huge datasets. Therefore the problems of partitioning a huge dataset effectively and alleviating the processing overhead of the partitioned data efficiently have been a critical factor for scalability and performance in distributed database system. In our work we utilized multicore servers to provide scalable service to our distributed system. The partitioning of database over multicore servers have emerged from a need for new architectural design of distributed database system from scalability and performance concerns in today's data deluge. The system allows uniform access through a web service interface to concurrently distributed databases over multicore servers, using SQMD (Single Query Multiple Database) mechanism based on publish/subscribe paradigm. We will present performance results with the distributed database system built on multicore server, which is time intensive with traditional architectures. We will also discuss future works.

• Asia pacific journal of information systems
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• 제6권1호
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• pp.21-38
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• 1996

This paper investigates the performance improvement opportunities through a resiliency mechanism in the distributed primary/backup database system. Recognizing that a distributed transaction executes at several servers during its lifetime, we propose a resiliency mechanism which allows continuous transaction processing in distributed database server systems in the presence of a server failure. In order to perform continuous transaction processing despite failures, every state change of a transaction processing can be saved in the backup server. Obviously, this pessimistic synchronization may give more burdens than benefits to the system. Thus, the tracking needs not be done synchronously with the transaction progress. Instead, the state of all transaction processing in a system is saved periodically. This activity is referred to as a savepoint. Then, the question is how often the savepoint has to be done. We derive the optimal savepoint to identify the optimization parameters for the resilient transaction processing system.

• 한국데이타베이스학회:학술대회논문집
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• 한국데이타베이스학회 1994년도 DB산업기술 활성화를 위한 학술대회 및 기술 심포지움
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• pp.105-129
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• 1994

The information system of corporations are facing a new environment expressed by miniaturization, decentralization and Open System. It is therefore of utmost importance for corporations to adapt flexibly th such new environment by providing for corresponding changes to their existing information systems. The objectives of this study are to identify this new environment faced by today′s information system and develop effective methods for data resource management under this new environment. In this study, it is assumed that the new environment faced by information systems can be specified as Distributed Computing Environment, and in order to achieve such system, presents Client/server architecture as its representative computing structure, This study defines Client/server architecture as a computing architecture which specialize the fuctionality of the client system and the server system in order to have an application distribute and perform cooperative processing at the best platform. Furthermore, from among the five structures utilized in Client/server architecture for distribution and cooperative processing of application between server and client this study presents two different data management methods under the Client/server environment; one is "Remote Data Management Method" which uses file server or database server and. the other is "Distributed Data Management Method" using distributed database management system. The result of this study leads to the conclusion that in the client/server environment although distributed application is assumed, the data could become centralized (in the case of file server or database server) or decentralized (in the case of distributed database system) and the data management method through a distributed database system where complete responsibility and powers with respect to control of data used by the user are given not only is it more adaptable to modern flexible corporate environment, but in terms of system operation, it presents a more efficient data management alternative compared to existing data management methods in terms of cutting costs.

• Asia pacific journal of information systems
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• 제8권3호
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• pp.21-36
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• 1998

Group collaborative systems are recently emerging to support a group of users engaged in common tasks such as group decision making, engineering design, or collaborative writing. Simultaneously, as communications networks and distributed database systems become core underlying architecture of the organization, the need of collaborative systems are gaining more attentions from industry. In such collaborative systems, as the shared objects may evolve constantly or change for operational purposes, providing the users with synchronized and consistent views of the shared object and maintaining the consistency between shared object and replicated objects are important to improve the overall productivity. This paper provides an change management framework for the group collaborative systems to facilitate managing dependency relationships between shared objects and dependents, and coordinating change and propagation activities in distributed computing environments. Specifically, the framework adopts an object-oriented database paradigm and presents several object constructs capturing dependency management and change notification mechanisms. And the proposed framework accommodates both persistent dependents such as replicated data and transient dependents such as various user views in a single formalism. A prototype system is developed on a commercial object-oriented database management system called OBJECTSTORE using the C++ programming language.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권7호
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• pp.3533-3549
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• 2019

A big database utilizes the establishing network technology, and it became an emerging trend in the computing field. Therefore, there is a necessity for an optimal and effective data distribution approach to deal with this trend. This research presents the practical perspective of designing and implementing distributed database features. The proposed system has been establishing the satisfying, reliable, scalable, and standardized use of information. Furthermore, the proposed scheme reduces the vast and recurring efforts for designing an individual system for each university, as well as it is effectively participating in solving the course equivalence problem. The empirical finding in this study shows the superiority of the distributed system performance based on the average response time and the average waiting time than the centralized system. The system throughput also overcomes the centralized system because of data distribution and replication. Therefore, the analyzed data shows that the centralized system thrashes when the workload exceeds 60%, while the distributed system becomes thrashes after 81% workload.

• 산업경영시스템학회지
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• 제18권33호
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• pp.1-10
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• 1995

The allocation of files is essential to the efficiency and effectiveness of a distributed system that must meet geographically dispersed data processing demands. In this paper, we address an optimization model that generates optimal file migration policies in distributed database systems. The proposed model is a more generalized model that includes system's capacity constraints - computing sites' storage capacity and communication networks' capacity - which have not taken into consideration in previous researches. Using this model, we can establish initial file allocation, file reallocation and file migration polices that minimize a system operating cost under system's capacity constraints at an initial system design or reorganization point The proposed model not only can be adopted by small-sized systems but also provides a foundation for effective and simple heuristics for adaptive file migration in large systems.

• 정보기술과데이타베이스저널
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• 제7권2호
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• pp.1-15
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• 2000

The World-Wide-Web have many advantages as a front-end of database systems. Hence in Internet applications, such as E-Commerce systems, the requirements for Web-based database applications have been increasing. In this work we propose a framework for java-based Web database applications-JaWAF(Java-based Web Application Framework). JaWAF has the 3-tier architecture of Client/Server, and consists of database gateway, application server, and communication and message component. When this framework is applied to the database applications developments, it can provide advantages, such as ease understanding and fast implementations of the Web applications. Thus we can build 3-tier Web-based database application systems with high scalability and distributed processing capability. Database gateway in JaWAF works as a daemon process that connects to the database systems and waits for requests from clients, and supports state-oriented service between clients and database servers. Hence the performance of Web applications could be increasing.

• International Journal of Computer Science & Network Security
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• 제21권12호
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• pp.280-292
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• 2021

Enterprise Resource Planning (ERP) is a software that manages and automate the internal processes of an organization. Process speed and quality can be increased, and cost reduced by process automation. Odoo is an open source ERP platform including more than 15000 apps. ERP systems such as Odoo are all-in-one management systems. Odoo can be suitable for small and medium organizations, but duo to efficiency limitations, Odoo is not suitable for the large ones. Furthermore, Odoo can be implemented on both local or public servers in which each has some advantages and disadvantages such as; the speed of internet, synced data or anywhere access. In many cases, there is a persistent need to have more than one synchronized Odoo instance in several physical places. We modified Odoo to support this kind of requirements and improve its efficiency by replacing its standard database with a distributed one, namely CockroachDB.