• Journal of Digital Convergence
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• v.15 no.3
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• pp.181-186
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• 2017

The system optimization is a technique that changes the structure of the program in order to extract the duplicated modules without changing the source code, reuse of the extracted module. Structure-oriented development and object-oriented development are efficient at crosscutting concern modular, however can't be modular of crosscutting concept. To apply the crosscutting concept in an existing system, there is a need to a extracting technique for distributed system optimization module within the system. This paper proposes a method for extracting the redundant modules in the completed system. The proposed method extracts elements that overlap over a source code analysis to analyze the data dependency and control dependency. The extracted redundant element is used to program dependency analysis for the system optimization. Duplicated dependency analysis result is converted into a control flow graph, it is possible to produce a minimum crosscutting module. The element extracted by dependency analysis proposes a system optimization method which minimizes the duplicated code within system by setting the crosscutting concern module.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.6
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• pp.648-653
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• 2012

Cavity pressure, an important factor in injection molding process, should be minimized to enhance injection molding quality. In this study, we decided the locations of valve gates to minimize the maximum cavity pressure. To solve this problem, we integrated MAPS-3D (Mold Analysis and Plastic Solution-3Dimension), a commercial injection molding analysis CAE tool, using the file parsing method of PIAnO (Process Integration, Automation and Optimization) as a commercial process integration and design optimization tool. In order to reduce the computational time for obtaining the optimal design solution, we performed an approximate optimization using a meta-model that replaced expensive computer simulations. To generate the meta-model, computer simulations were performed at the design points selected using the optimal Latin hypercube design as an experimental design. Then, we used micro genetic algorithm equipped in PIAnO to obtain the optimal design solution. Using the proposed design approach, the maximum cavity pressure was reduced by 17.3% compared to the initial one, which clearly showed the validity of the proposed design approach.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10b
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• pp.697-699
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• 2004

Stochastic Neighbor Embedding(SNE) is a probabilistic method of mapping high-dimensional data space into a low-dimensional representation with preserving neighbor identities. Even though SNE shows several useful properties, the gradient-based naive SNE algorithm has a critical limitation that it is very slow to converge. To overcome this limitation, faster optimization methods should be considered by using trust region method we call this method fast TR SNE. Moreover, this paper presents a couple of useful optimization methods(i.e. conjugate gradient method and Newton's method) to embody fast SNE algorithm. We compared above three methods and conclude that TR-SNE is the best algorithm among them considering speed and stability. Finally, we show several visualizing experiments of TR-SNE to confirm its stability by experiments.

• Proceedings of the Korean Information Science Society Conference
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• 2006.06d
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• pp.163-165
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• 2006

비구조적인 피어-투-피어 시스템은 구조적 피어-투-피어 시스템에 비해 동적인 상황에 적합하지만 메시지가 여러 다른 피어를 이동하면서 검색하기 때문에 검색 시간이 길고 검색의 성공률이 낮다. 이러한 문제를 해결하기 위해 우수 피어를 사용한 계층적 피어-투-피어 시스템이 연구 되었다. 효율적인 계층적 피어-투-피어 시스템을 구성하기 위해서는 어떤 피어가 얼마나 많이 우수 피어로 선택되어야 하는지가 중요하다. 본 논문에서는 기존에 연구된 자기 조직적 링 구조 기법을 기반으로 우수 피어의 비율을 환경에 적응하게 하는 시스템을 제안한다. 환경에 적합한 비율 조절을 위해 효율적으로 최적 또는 최적에 가까운 해를 찾는 것으로 알려진 입자 군집 최적화(PSO : Particle Swarm Optimization)기법을 사용하였고 성능 평가 결과 PSO를 적용한 시스템에서 성능 향상을 볼 수 있었다.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06a
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• pp.282-284
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• 2012

임베디드 분야에서 전력 에너지 소비 문제는 시스템을 설계하는데 있어서 매우 중요한 이슈가 되고 있다. 특히 휴대성이 강조되는 모바일 장치의 제한된 전력을 효율적으로 이용하기 위해서 하드웨어적인 관리 못지않게 소프트웨어적인 관리 기술의 필요성이 강조되고 있으며 전력 소비 관리를 위한 최적화된 컴파일러 기법이 연구되고 있다. 이 논문에서는 모바일 장치에서 구동되는 어플리케이션의 전력 에너지 소비를 줄이기 위한 전역 코드 스케줄링 기법을 제시한다. 이를 위해, 재목적 소프트웨어 개발 도구인 EXPRESSION의 컴파일러인 EXPRESS의 코드 최적화 기법을 이용하여 전력 에너지 효율적인 전역 코드 스케줄링 모델을 설계하고 성능평가 방법을 제시한다.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06d
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• pp.297-299
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• 2012

In this paper, we introduce a joint flow control and scheduling algorithm for multi-hop cognitive radio networks with spectrum underlay. Our proposed algorithm maximizes the total utility of secondary users while stabilizing the cognitive radio network and still satisfies the total interference from secondary users to primary network is less than an accepted level. Based on Lyapunov optimization technique, we show that our scheme is arbitrarily close to the optimal.

• Proceedings of the KIPE Conference
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• 2012.11a
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• pp.33-34
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• 2012

As the distributed power system with PV and ESS is highlighted to be one of the most prominent structure to replace the traditional electric power system, power flow scheduling is expected to bring better system efficiency. Optimal energy management system (EMS) where the power from PV and the grid is managed in time-domain using ESS needs an optimization process. In this paper, main optimization method is implemented using dynamic programming (DP). To overcome the drawback of DP in which ideal future information is required, prediction stage precedes every EMS execution. A simple auto-regressive moving-average (ARMA) forecasting followed by a PI-controller updates the prediction data. Assessment of the on-line optimal EMS scheme has been evaluated on several cases.

• Journal of information and communication convergence engineering
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• v.12 no.2
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• pp.128-134
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• 2014

In this paper, we present a graphics processing unit (GPU)-based matching technique for the purpose of fast feature matching between different images. The scale invariant feature transform algorithm developed by Lowe for various feature matching applications, such as stereo vision and object recognition, is computationally intensive. To address this problem, we propose a matching technique optimized for GPUs to perform computations in less time. We optimize GPUs for fast computation of keypoints to make our system quick and efficient. The proposed method uses a self-organizing map feature matching technique to perform efficient matching between the different images. The experiments are performed on various image sets to examine the performance of the system under varying conditions, such as image rotation, scaling, and blurring. The experimental results show that the proposed algorithm outperforms the existing feature matching methods, resulting in fast feature matching due to the optimization of the GPU.

• Proceedings of the KIEE Conference
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• 1999.07b
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• pp.592-595
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• 1999

In this paper, we propose a unified method to solve the various robust filtering problem for a class of uncertain discrete time systems. Generally, to solve the robust filtering problem, we must convert the convex optimization problem with uncertainty blocks to the uncertainty free convex optimization problem. To do this, we derive the robust matrix inequality problem. This technique involves using constant scaling parameter which can be optimized by solving a linear matrix inequality problem. Therefore, the robust matrix inequality problem does not conservative. The robust filter can be designed by using this robust matrix inequality problem and by considering its solvability conditions.

• JSTS:Journal of Semiconductor Technology and Science
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• v.3 no.1
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• pp.33-41
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• 2003

In this work, process optimization techniques for high frequency performance of HBTs are presented. The techniques are focused on reducing parasitic base resistance and base-collector capacitance, which are key elements determining the high frequency characteristics of HBTs. Several fabrication techniques, which can significantly reduce the parasitic elements of the HBTs for improved high frequency performance, are proposed and verified by the measured data of the fabricated devices.