• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.8
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• pp.10-20
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• 2002

The present paper investigates methods to control dynamic stall using an optimal approach. An unsteady aerodynamic sensitivity analysis code is developed by a direct differentiation method from a two-dimensional unsteady compressible Navier-Stokes solver including a two-equation turbulence model. Dynamic stall control is conducted by minimizing an objective function defined at an instant instead of integrating for a period of time. Unsteady sensitivity derivatives of the objective function are calculated by the sensitivity code, and optimization is carried out using a linear line search method at every physical time step. Numerous examples of dynamic stall control using control parameters such as nose radius, maximum thickness of airfoil, or suction show satisfactory results.

• 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.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.7
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• pp.701-708
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• 2009

The flight control law of developed flight control computer(DFLCC) is developed based on operation flight program of advanced trainer aircraft full scale development final configuration. The flight control law design is used common use development tool in GUI(Graphic User Interface) environment. The flight control law transformed to C-Code is reflected in OFP. The OFP is verified by the standardized verification process. But, before standardized verification process, we need preliminary verification process such as similarity of flight control law and reliability of developed HILS. Similarity of flight control law is verified by comparing the aircraft response of advanced trainer aircraft and those of the developed control law. Also, reliability of developed HILS is verified by comparing the aircraft response of HILS and Non-real time simulation result. This paper verifies similarity of developed control law and reliability of HILS environment as comparing aircraft response.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1996.10a
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• pp.515-518
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• 1996

• Proceedings of the Korean Nuclear Society Conference
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• 2003.05a
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• pp.182-182
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• 2003

• The Journal of Korean Association of Computer Education
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• v.18 no.4
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• pp.63-70
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• 2015

Program source code is a set of complex syntactic information which are expressed in text forms, and contains complex logical structures. Structural and logical complexity inside source code become barriers in applying visualization techniques shown in traditional big-data approaches when the volume of source code become over ten-thousand lines of code. This paper suggests a procedure for making visualization of structural characteristics in source code. For this purpose, this paper defines internal data structures as well as inter-procedural relationships among functions. The paper also suggests a means of outlining the structural characteristics of source code by visualizing the source codes with network forms The result of the research work can be used as a means of controling and understanding the massive volume of source code.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.3 no.4
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• pp.723-736
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• 1999

Code optimization phase in a compiler are very important because the phase reduces the running time and the storage size of machine codes. I developed flow analyzers and optimizers on intermediate codes. The flow analyzers generate control-flow and data-flow information. The optimizers transform the intermediate codes into the improved codes using this information. This paper describes the development of flow analyzers and optimizers. I also examined the execution performance, the cost and the dependency of each optimization.

• Proceedings of the Korea Information Processing Society Conference
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• 2000.10a
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• pp.465-468
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• 2000

본 논문에서는 인식코드를 전송할 수 있는 modulator 뿐만 아니라 Reader system으로부터 코드 전송제어 명령어를 수신할 수 있고 향후 EEPROM과 더불어 인식코드를 수정할 수 있는 RFID (Radio Frequency IDentification) Transponder 칩 설계에 관한 내용을 다룬다. RFID칩은 배터리를 사용하지 않고 명령어와 함께 형성되는 Field로부터 전원을 생성하고 동시에 코드를 제공하는 Full-Duplex 구조로 설계하였다. Transponder IC는 power-generation 회로, clock generation 회로, digital block, modulator, overvoltage protection 회로로 구성된다. 설계된 칩은 저전력 회로를 적용하여 원거리 transponder칩을 구현할 수 있도록 하였다. 설계된 회로는 $0.6{\mu}m$ 현대 CMOS 공정으로 레이아웃 하였으며 제작중에 있다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.10 no.3
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• pp.147-152
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• 1985

The error-trapping decoder is constructed for the (7, 3) Reed-Solomon code. The syndrome resister is constructed with the encoder and the substanial test logic circuits. The element of GF(8) is represented by the triple D-flip-floops. The hardware is constructed. And it is controlled by the micro computer(Apple II). The time for the encoding and the decoding were $350\musecs and 910u secs respectively. The experimental results show that the two symbol errors were corrected and 4-bit-binary-burst errors were also corrected.

• Journal of KIISE:Software and Applications
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• v.30 no.1_2
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• pp.73-80
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• 2003

The Java programming language is designed for developing effective applications in a heterogeneous network environment. Major problem in Java is its performance. many attractive features of Java make the development of software easy, but also make it expensive to support ; applications written in Java are often much slower than their counterparts written in C or C++. To use Java`s attractive features without the performance penalty, sophisticated optimizations and runtime systems are required. Optimising Java bytecode has several advantages. First, the bytecode is independent of any compiler that is used to generate it. Second, the bytecode optimization can be performed as a pre=pass to Just-In-Time(JIT) compilation. Many attractive features of Java make the development of software easy, but also make it expensive to support. The goal of this work is to develop automatic construction of code optimizer for Java bytecode. We`ve designed and implemented a Bytecode Optimizer that performs the peephole optimization, bytecode-specific optimization, and method-inlining techniques. Using the Classfile optimizer, we see up to 9% improvement in speed and about 20% size reduction in Java class files, when compared to average code using the interpreter alone.