• Proceedings of the Korea Information Processing Society Conference
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• 2004.05a
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• pp.519-522
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• 2004

자바는 현재 가장 널리 사용되는 범용 프로그래밍 언어중 하나로 컴파일러에 의해 중간언어인 바이트코드로 변환되며 JVM(Java Virtual Machine)에 의해 실행되는 플랫폼 독립적인 언어이다. SIL(Standard Intermediate Language)은 Microsoft사의 .NET 언어와 SUN사의 Java 언어 등을 모두 수용할 수 있는 임베디드 시스템을 위한 중간언어로 가상기계인 EVM(Embedded Virtual Machine)에서 실행된다. 본 논문에서는 자바 프로그램을 컴파일하여 생성된 클래스 파일에서 Oolong 코드를 추출하고 추출된 Oolong 코드를 EVM의 SIL 코드로 변환하여 자바로 구현된 프로그램이 EVM에서 실행되도록 하는 Bytecode-to-SIL 번역기 시스템을 구현하였다. 그리고 본 번역기 시스템을 다른 플랫폼에 용이하게 설치하기 위한 재목적성(retargetability)을 위해 단일패스(one-pass)을 사용하는 기존의 번역기들과 달리 AST를 이용한 컴파일러 기법을 사용하여 AST가 가지고 있는 정보에 대해 최적화 작업을 수행하여 보다 효과적인 코드 변환을 할 수 있도록 설계하였다.

• Proceedings of the Korea Multimedia Society Conference
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• 2002.05d
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• pp.1007-1011
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• 2002

소형 플랫폼에 자바 언어를 구동하기 위한 PJAVA VM(이하 PVM)이 많은 관심을 끌고 있다. PVM 역시 JVM과 같이 클래스 로더, 서브시스템, 런타임 데이터 영역 (메소드 영역, 힙 자바 스택, PC레지스터, 원시 메소드 스택), 실행 엔진으로 구성되어 있다. 본 논문의 서론은 PDA 및 set-top등을 소개하고 JAVA 언어를 구동하기 위해 필요한 플랫폼을 소개하고, J2ME와 PJAVA를 관계를 소개하였다. 관련연구는 PVM의 메소드 구조에 대해 연구하였다. 그리고 본론으로 PVM에서 프로세서 마무리 처리과정을 분석하고 이 과정에서 프로세서의 종료 작업 알고리즘을 개선 하였다.

• Journal of KIISE:Software and Applications
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• v.35 no.5
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• pp.281-287
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• 2008

Data transfers occur during the execution time of a Java program, from constant to variable, from variable to other variable and so on. Data are located in memory and hence data transfer requires access to memory. As memory access generates both time delay and energy consumption it is absolutely necessary to know the data transfer overheads incurred among different paths not only to write an efficient program but also to build a high-performance Java virtual machine. In this paper we classify Java memory into three different regions, constant, local variable, and field, and then investigate data transfer overheads among these regions. The result says that the transfer between local variables incur the least overhead usually, while the transfer between fields incur the most. The difference of overheads reaches up to a double. Optimization techniques like JIT reduces the data transfer overhead dramatically. It is observed that the overhead is reduced from 14 to 27 times for the case of Hotspot JVM.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.5
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• pp.1058-1067
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• 2004

Java virtual machine provides code compactness, simple execution engines, and platform-independence which are important features for small devices such as mobile or embedded device, but it has a big problem, such as low throughput due to stack-oriented operation. In this paper hardware lava accelerator targeted for mobile or embedded application is designed to eliminate the slow speed problem of lava virtual machine. The designed lava accelerator can execute 81 instructions of Java virtual machine(JVM)'s opcodes and be used as Java coprocessor of conventional 32-bit RISC processor with efficient coprocessor interface and instruction buffer. It consists of about 14,300 gates and its maximum operating frequency is about 50 Mhz under 0.35um CMOS technology.

• The KIPS Transactions:PartA
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• v.14A no.3 s.107
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• pp.173-184
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• 2007

Garbage collection in the Java virtual machine is a core function that relieves application programmers of difficulties related to memory management. In this paper, we evaluate and analyze the performance of GenGC and GenRGC, garbage collectors for embedded Java virtual machines. For performance evaluation, we employ CVM, a real embedded Java virtual machine developed by Sun Microsystems, Inc., as a platform and also use a widely-used SpecJVM98 as a set of benchmark programs. To compare the performance of GenGC and GenRGC, we first evaluate the time of garbage collection and the delay time caused by garbage collection. Second, for more detailed performance analysis of GenRGC, we evaluate the time of garbage collection and the delay time caused by garbage collection while changing the sizes of a block and a frame. Third, we analyze the size of storage space required for performing GenRGC, and show GenRGC to be suitable for embedded environment with a limited mont of memory. Since CVM is the most representative one of embedded Java virtual machines, this performance study is quite meaningful in that we can predict the performance of garbage collectors in real application environments more accurately.

• Journal of Korea Multimedia Society
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• v.16 no.2
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• pp.190-197
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• 2013

Since domestic and foreign platform companies and mobile carriers adopt and use different kinds of smart platforms, developers should develop or convert contents according to each smart platform to provide a single smart content for customers. It takes long time and a lot of money to convert the conventional smart contents in order to serve other smart platforms. For the reason, more attention has been paid on Smart Cross Platform or Hybrid Platform, the core technologies of OSMU(One Source Multi Use) in which, once a program is coded, it can be executed in any platforms regardless of development languages. As a result, PhoneGap and HTML5 based Sencha Touch have been introduced. In this paper, we developed the smart virtual machine, which is built in smart cross platform based smart devices, unlike Android, iOS, Windows Phone devices being dependent of platforms, and helps to download and execute applications, being independent of platforms. the smart virtual machine supports C/C++, and Java language, being differentiated from JVM by sun microsystems that supports only Java language and .NET framework by microsoft that supports only C, C++ and C#. Therefore, it provides contents developers with the environment where they can get a wide range of options in choosing a language and develop smart contents.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10c
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• pp.106-108
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• 2001

본 논문에서는 임베디드 자바 가상 대신(Embedded Java Virtual Machine)과 임베디드 실시간 운영체제(Embedded Real-Time Operating System)인 iRTOS$^{TM}$를 통합하기 위한, 설계 및 구현 내용을 기술하고자 한다. 인터넷 가전을 위한 실시간 운영체제 기반의 통합 환경은 각 가정에서 사용하는 정보 가전 제품들을 인터넷에 연결하여 사용함으로써 사용자에게 좀 더 효율적이며. 편리한 서비스를 제공할 수 있다. 또한 어떠한 플랫폼에도 구애 받지 않고 동작 할 수 있는 자바를 실행하기 위한 내장형 JVM 의 추가로, 기존의 플랫폼 의존적인 방법을 벗어나 어떠한 가전 기기상해서도 자바로 개발된 모든 기능들을 동일한 조건으로 동작시킬 수 있다는 장점을 갖는다. 본 논문에서는 통합 설계서의 세부 내용과 통합 방법에 대해 언급하고자 한다.

• Journal of KIISE:Software and Applications
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• v.30 no.1_2
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• pp.58-72
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• 2003

The objects generated by the keyword new in Java are automatically managed by the garbage collector Inside Java Virtual Machine (JVM) not like using the keywords free or delete in C or C++ programming environments. This provides a means of freedom of memory management burden to the application programmers. The garbage collector however. inherently has its own run time execution overhead. Thus it causes the performance degradation of JVM significantly. In order to mitigate the execution burden of a garbage collector, we propose a novel way of dynamic memory management scheme in Java environment. In the proposed method, the application programmers can explicitly manage the objects In a simple way, which in consequence the run-time overhead can be reduced while the garbage collector is under processing. In order to accomplish this, Java application firstly calls the APIs that arc implemented by native Jana, and then calls the subroutines depending on the JVM, which in turn support to keep the portability characteristic Java has. In this way, we can not only sustain the stability in execution environments. but also improve performance of garbage collector by simply calling the APIs. Our simulation study show that the proposed scheme improves the execution time of the garbage collector from 10.07 percent to 52.24 percent working on Mark-and-Sweep algorithm.

• Journal of Korea Multimedia Society
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• v.6 no.2
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• pp.276-287
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• 2003

Wireless Internet has to offer various types of services as much as wired network does in the scope of Internet business. The browser for simple data service using SMS in the early wireless internet cannot serve various multimedia contents. In this paper, We design and implement a Java browser that runs Java program, by adding JVM(Java Virtual Machine) into the web browser for mobile terminals. The Java browser for mobile terminals dynamically loads various Java program you want. This browser makes it possible to be multipurpose mobile terminals for E-Commerce, E-Wallet, Game Device.

• Convergence Security Journal
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• v.12 no.2
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• pp.107-113
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• 2012

Recently, according to the establishment of personal information protection Act, the public and private organizations are taking a step to protect personal information rights and interests by employing the technical methods such as the access control mechanism, cryptography, etc. The result of the personal information leakage causes a serious damage for the organization image and also has to face with the responsibility by law. However, applying access control and cryptographic approach on the personal information item for every connection to large database system causes significant performance degradation in a large database system. In this paper, we designed and implemented the light weight system using JVM (Java Virtual Machine) for the Oracle DBMS environment which the concurrent transaction occurs many, thereby the proposed system provides the minimum impact on the system performance and meets the need of personal information protection. The proposed system was validated on the personal information protection system which sits on a 'A' public organization's portal site and personnel information management system.