• The KIPS Transactions:PartD
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• v.13D no.7 s.110
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• pp.939-946
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• 2006

Although the Java bytecode has numerous advantages, there are also shortcomings such as slow execution speed and difficulty in analysis. In order to overcome such disadvantages, bytecode analysis and optimization must be performed. We implements CTOC for optimized codes. An extended CFG must be first created in order to analyze and optimize a bytecode. Due to unique bytecode properties, the existing CFG must be expanded according to the bytecode. Furthermore, the CFG must be converted into SSA Form for a static analysis, for which calculation is required for various information such as the dominate relation, dominator tree, immediate dominator, $\phi$-function, rename, and dominance frontier. This paper describes the algorithm and the process for converting the existing CFG into the SSA From. The graph that incorporates the SSA Form is later used for type inference and optimization.

• Korean Journal of Optics and Photonics
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• v.19 no.1
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• pp.60-67
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• 2008

An all-optical 4-bit Gray code to binary coded decimal (BCD) converter by means of commercially available numerical analysis tool (VPI) was demonstrated, for the first time to our knowledge. Circuit design approach was modified appropriately in order to fit the electrical method on an all-optical logic circuit based on a cross gain modulation (XGM) process so that signal degradation due to the non-ideal optical logic gates can be minimized. Without regenerations, Q-factor of around 4 was obtained for the most severely degraded output bit (least significant bit-LSB) with 2.5 Gbps clean input signals having 20 dB extinction ratio. While modifying the two-level simplification method and Karnaugh map method to design a Gray code to BCD converter, a general design concept was also founded (one-level simplification) in this research, not only for the Gray code to BCD converter but also for any general applications.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06a
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• pp.268-270
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• 2012

동적 코드 분석 도구는 동적 컴파일(Just-in-Time Compile)을 통한 코드 변환 기술을 이용하여 응용프로그램 실행 중 기계어 수준의 코드를 분석한다. 기존의 동적 코드 분석 도구는 변환과정에서의 부하가 크기 때문에 리얼타임 프로그램에 적용하기 어렵다. 본 논문에서는 기존 동적 코드 분석 도구의 동적 컴파일 기법과 컴파일 프레임워크인 LLVM의 동적 컴파일 기법의 성능을 비교, 분석하였다. 이를 통해 LLVM의 동적 컴파일 기법을 이용한 높은 수행 성능을 가진 동적 코드 분석 도구의 설계 방안을 모색한다.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.2
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• pp.124-133
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• 2009

There are many different ID representation forms depending on the media or applications. In case of RFID tag, ID representation form must be followed by the rule of ISO/IEC 15962. In this study, we developed the efficient ID conversion algorithm between ID representation form on RFID tag and Internet. The main idea is on the use of XML based ID profiles and three step logical IDs forms. The algorithm was tested by the typical three kinds of real IDs such as EPC, ISO/IEC 15459 KKR Code, and mCode which are the typical meta-IDs can be defined in ISO/IEC 18000-6C tag.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.7
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• pp.1462-1470
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• 2003

According to the necessity about information security as well as the advance of IT system and the spread of the Internet, a variety of cryptography algorithms are being developed and put to practical use. In addition the technique about cryptography attack also is advanced, and the algorithms which are strong against its attack are being studied. If the linear transformation matrix in the block cipher algorithm such as Substitution Permutation Networks(SPN) produces the Maximum Distance Separable(MDS) code, it has strong characteristics against the differential attack and linear attack. In this paper, we propose a new algorithm which cm estimate that the linear transformation matrix produces the MDS code. The elements of input code of linear transformation matrix over GF$({2_n})$ can be interpreted as variables. One of variables is transformed as an algebraic formula with the other variables, with applying the formula to the matrix the variables are eliminated one by one. If the number of variables is 1 and the all of coefficient of variable is non zero, then the linear transformation matrix produces the MDS code. The proposed algorithm reduces the calculation time greatly by diminishing the number of multiply and reciprocal operation compared with the conventional algorithm which is designed to know whether the every square submatrix is nonsingular.

• The Journal of the Korea Contents Association
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• v.5 no.3
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• pp.73-81
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• 2005

CTOC(Classes To Optimized Classes) is a Java bytecode framework for optimization and analysis. Although Java bytecode has a significant amount of type information embedded in it, there are no explicit types for local variables. However, knowing types for local variables is very useful for both program optimization and analysis. This paper is a first part of CTOC framework. In this paper, we present methods for inferring static types for local variables in a 3-address, stackless, representation of Java bytecode. We use SSA Form(Single Static Assignment Form) for spliting local variables. Splited local variables will use to prepare for static type inference.

• The Journal of the Korea Contents Association
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• v.8 no.6
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• pp.82-88
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• 2008

ARM processors are being utilized in a variety of embedded systems. It is also that most ARM processor accepts C application, and then generates ARM assembly code using GNU gcc Cross-compiler. For the purpose of improving the quality of code generated and the efficient code generation, the various researches are underway. In this paper, we generates the ARM assembly code from the ANSI C programs using Syntax-directed Translation Techniques, and then the performance evaluation results for our research experimental compare to GNU gcc Cross-compiler are described. The techniques are presented in this research compared to GNU gcc cross-compiler very simple and convenient in extension of the production rules.

• The Transactions of the Korea Information Processing Society
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• v.5 no.8
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• pp.2027-2040
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• 1998

In this paper, we present efficient reconfigurable mesh algorithms for transforming between a binary image and its corresponding boundary code. These algorithms use $n\timesn\timesn$ processors when the size of the binary image is $n\timesn$. Recent published results show that these transformations can be done in O(1) time using $O(n^4)$ processors. The number of processors used by these algorithms is very large compared to the number of pixels in the image. Here, we present fast transformation algorithms which use $n^3 processors only. the transformation from a houndary code to a binary image takes O(1) time, and the converse transformation takes O(log n) time.

• Annual Conference of KIPS
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• 2010.11a
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• pp.322-325
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• 2010

본 논문은 다른 프로세서간의 어셈블리 코드를 자동으로 변환하는 방법에 대해 소개한다. 어셈블리 언어는 기계어를 사람이 알아보기 쉽도록 만든 저급 언어로서 레지스터 접근과 같은 하드웨어 수준의 작업이 가능한 반면, 컴퓨터 아키텍처에 따라 어셈블리도 다르다. 이에 따라 새로운 프로세서에서 어셈블리 코드가 포함된 프로그램을 동작시키기 위해서는 어셈블리 코드 부분을 새로 작성하여야 한다. 어셈블리를 작성하는 것은 많은 시간이 필요하고 버그가 발생할 확률이 높다. 본 논문에서는 새로 작성할 어셈블리 코드를 동일한 동작을 하는 다른 프로세서의 어셈블리 코드를 통해 생성해내는 방법을 소개한다.

• Annual Conference of KIPS
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• 2010.04a
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• pp.918-921
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• 2010

본 연구에서는 Simulink Model(이하 Model)을 C Code 로 변환시켜주는 자동 코드 생성기, SimAutoCodeGenerator 를 제안하였다. Model 의 테스트케이스를 생성하기 위한 작업에서 반복적인 프로그램의 실행을 통한 테스터와의 다양한 피드백이 필요하다. 이때, Simulink는 이런 작업을 하는 데 있어서 적절한 정보를 제공하기 어려울 뿐만 아니라 테스트 케이스를 생성하는데 필요한, 실행 시 특정 시점으로 돌아가는 기능을 수행하기 위해서는 프로그램을 정지한 후 다시 실행해야하는 문제점을 가지고 있다. 본 연구에서는 이와같은 단점을 보완하기 위하여 Model 을 C 코드로 변환하였다. 생성된 C 코드는 Model 과의 일치성을 증명한 후 자동 테스트케이스 생성을 위한 프로그램에 쓰이게 될 것이다. 먼저 C 코드의 생성 메커니즘을 알아보고 생성된 C 코드와 Model 의 일치성을 증명하였다.