• Journal of Korea Society of Industrial Information Systems
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• v.9 no.1
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• pp.69-76
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• 2004

Recently, smart cards with multi-applications loaded are becoming popular owing to many advantages. As many casual users would like to reduce the number of plastic cards, and card issuers want to upgrade the existing applications or add the new applications, and developers wish to reduce the development turn-around time, multi-applications smart cards are becoming important. In addition, many advantages exist between the business partners as smart card applications can share critical information. New operating systems such as JavaCard and MULTOS are suggested for the multi-applications smart card service recently. In this paper, after we review the principles of operations of smart card, we propose the various security mechanisms for the multi-application JavaCard service environment, which is becoming de facto standard in the industry.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10b
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• pp.18-20
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• 1998

JDBC는 Java 응용 프로그램이나 apllet에서 SQL 문을 수행하기 위해서 Javasoft에서 정의한 Java API로서, DBMS에 비의존적이고 플랫폼에도 독립적인 Java 응용 프로그래밍 기법을 제공한다. 일반 DBMS 응용 프로그램과 마찬가지로 Java 응용 프로그램에서도 기존에 구축된 동기종 또는 이기종의 데이터베이스를 동시에 접근해서 처리해야 하는 경우가 발생하다. 이 경우 한 응용 내에서의 여러 DBMS 연결은 불가피하다. 이러한 다중 연결의 지원은 응용 프로그램을 추가하는 작업이나 데이터베이스 자료 변환 작업을 감소시키는 효과가 있다. 이 논문에서는 JDBC 명세서 1.2에 따라 구현된 net-protocol all-Java driver 타입의 JDBC 드라이버가, JDBC 응용 클라이언트와 DBMS드라이버를 관리함으로써 한 Java 응용 프로그램내에서 다중 연결을 지원하는 M-JDBC(Multiple Database supporting)드라이버의 구조를 제시한다.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04a
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• pp.613-615
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• 2001

응용 프레임워크를 이용하여 응용 프로그램을 작성할 때, 응용 프레임워크와 함께, 그 프레임워크와 별도로 기존에 작성된 클래스를 이용하려면 다중 상속을 이용하거나 단순한 복사/붙이기와 같은 코드 재작성을 이용하여야 한다. 그러나 다중 상속은 여러 문제점을 가지고 있다. 코드 재작성은 단순한 짜깁기 이상은 될 수 없다. 또한 컴포넌트 기반의(Component-Based) 개발 방식을 따를 경우 프로그램 코드를 획득하거나 이해한다는 것도 쉬운 문제가 아니다. 역할 객체는 어떤 객체가 특정 콘텍스트에서 필요한 행동 양태(Behavior)를 가지는 객체를 의미한다. 본 논문에서는 이러한 프레임워크에 기작성된 클래스를 적용하기 위해 역할 객체를 이용하기를 제안하였다.

• The Transactions of the Korea Information Processing Society
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• v.4 no.1
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• pp.118-136
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• 1997

The multi-agent system is an environment in which applications solve tasks by cooperating with each other. In the multi-agent system, a user can solve complex problems by issuing a single command instead of a series of commands. However, agents depend on the state of other agents for they cooperate with each other. The problem worsens as multi-agent systems are connected to from a group of multi-agent systems. In this paper, we present the termination problem of an agent in a multi-agent system or a group of multi-agent systems. We also give asolution of the problem and present an example through implemented multi-agent systems.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.9
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• pp.461-476
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• 2003

Due to the implementation ease and alleviation of memory bottleneck effect, NUMA architecture has dominated in the multiprocessor systems for the past several years. However, because the NUMA system distributes memory in each node, frequent remote memory access is a key factor of performance degradation. Therefore, efficient design of RAC(Remote Access Cache) in NUMA system is critical for performance improvement. In this paper, we suggest Multi-Grain RAC which can adaptively control the RAC line size, with respect to each application behavior Then we simulate NUMA system with multi-grain RAC using MINT, event-driven memory hierarchy simulator. and analyze the performance results. At first, with profile-based determination method, we verify the optimal RAC line size for each application and, then, we compare and analyze the performance differences among NUMA systems with normal RAC, with optimal line size RAC, and with multi-grain RAC. The simulation shows that the worst case can be always avoided and results are very close to optimal case with any combination of application and RAC format.

• Journal of KIISE:Computing Practices and Letters
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• v.8 no.6
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• pp.630-638
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• 2002

Debugging for application Programs running in embedded Linux systems has mostly been done remotely due to the limited resources of the target systems. The gdb, which is one of the most famous debugger in Linux systems, does not support the debugging of the child processes which is created by the fork system call in local and remote environments. Therefore, by using gdb, developers can debug the application programs that have single-process structure in local and remote environments, but they cannot debug the application programs that have multi-process structures by using gdb in remote environments. Also, although developers can debug the application programs that have multi-process structures by using gdb in local environments, it needs additional and unnecessary codings. In this paper, we presents the remote debugging scheme that can be used for debugging multi-process structured applications. The proposed scheme is implemented by using the library wrapping scheme, and also uses the conventional system components such as gdb and gdbserver.

• Computational Structural Engineering
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• v.10 no.2
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• pp.51-55
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• 1997

미래의 구조공학 자동화시스템은 Windows NT 운영체제의 저가의 데스크탑 컴퓨터에서 작동하며 객체지행적 CAD를 사용할 것이다. 모든 구조공학 관련 프로그램들은 객체지향 프로그램기법과 병렬처리기술로 재개발될 것이다. 구조공학 관련 소프트웨어프로그램의 통하븐 Microsoft사의 Objected Linking and Embedding(OLe)자동화 기술과 강력한 다중처리, 그리고 Windows NT의 다중연결 서버 기능에 의하여 이루어진다. 이 논문에서는 먼저 Windows NT의 다중연결 서버 기능에 의하여 이루어진다. 이 논문에서는 먼저 Windows NT 운영체제의 데스크탑 컴퓨터에서 구조공학 자동화시스템의 응용현황을 설명하고 미래의 구조공학 자동화 소프트웨어의 개발경향과 전략에 대해 논하게 될 것이다.

• Smart Media Journal
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• v.3 no.1
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• pp.33-38
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• 2014

Even though the performance of microprocessor is improved continuously, the performance improvement of computing system becomes hard to increase, in order to some drawbacks including increased power consumption. To solve the problem, general-purpose computing on graphics processing units(GPGPUs), which execute general-purpose applications by using specialized parallel-processing device representing graphics processing units(GPUs), have been focused. However, the characteristics of applications related with graphics is substantially different from the characteristics of general-purpose applications. Therefore, GPUs cannot exploit the outstanding computational resources sufficiently due to various constraints, when they execute general-purpose applications. When designing GPUs for GPGPU, memory system is important to effectively exploit the GPUs since typically general-purpose applications requires more memory accesses than graphics applications. Especially, external memory access requiring long latency impose a big overhead on the performance of GPUs. Therefore, the GPU performance must be improved if hierarchical memory architecture which can reduce the number of external memory access is applied. For this reason, we will investigate the analysis of GPU performance according to hierarchical cache architectures in executing various benchmarks.

• Journal of KIISE:Computing Practices and Letters
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• v.6 no.4
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• pp.383-392
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• 2000

Currently, multiprocessors are evaluated almost exclusively with scientific applications. Commercial applications are rarely explored because it is difficult to obtain the source codes of commercial DBMS. Even when the source code is available, such as for POSTGRES, understanding the source code enough to perform detailed meaningful performance evaluations is a daunting task for computer architects.To evaluate multiprocessors with commercial applications, we have developed our own DBMS, called EZDB. EZDB is a parallelized DBMS, loosely inspired from POSTGRES, and running on top of a software architecture simulator. It is capable of executing parallel programs written in SQL. Contrary to POSTGRES, EZDB is not intended as a prototype for a production-quality DBMS. Its purpose is to easily run and evaluate the performance of commercial applications on multiprocessor architectures. To illustrate the usefulness of EZDB, we showed the cache performance data collected for the TPC-B benchmark on a shared-memory multiprocessor. The simulation results showed that the data structures exhibited unique sharing characteristics and that their locality properties and working sets were very different from those in scientific applications.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.11c
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• pp.1823-1826
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• 2002

최근 기존의 고정 단말기(PC)에서만 주로 행해지던 각종 다중 사용자 접속 온라인 응용이 PC와 PDA, 휴대폰 등이 공동 작업을 수행하는 멀티 플랫폼 기반 온라인 응용으로 전환되고 있다. 그러나 지금까지 멀티 플랫폼 기반 온라인 응용은 다중 사용자 환경 및 각 클라이언트의 처리 능력과 통신 속도의 비대칭을 고려하지 않아 컨텐츠가 매우 단순한 실정이다. 이 논문에서는 멀티 플랫폼 기반 온라인 응용의 인프라 구축을 위한 기술을 개발하고자 하였다. 구체적으로 멀티 플랫폼 단말 장치간의 데이터 송수신을 위한 네트워크 구조, 다중 사용자 환경의 일관성 제어 기법, 다양한 클라이언트간의 변경 전파 기술을 제안하였다. 그리고 여러 개의 PC, PDA, 휴대폰이 연동되어 동작하는 채팅 프로그램을 제작하여 제안한 기법들이 적절히 동작함을 보였다.