• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.255-256
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• 2015

본 논문에서는 새로이 제안되는 불연속모드 양방향 부스트-포워드 컨버터를 사용하는 셀 밸런싱 방법을 제안한다. 이 컨버터는 다중입력과 다중출력의 양방향 배터리 충방전을 다루고, 다중직렬 배터리의 전압 셀 밸런싱에 초점을 두었다. 여러 입력 배터리의 전압 차가 나지 않을 때는 부스트 컨버터가 작동하고, 레퍼런스가 되는 입력 배터리와 다른 입력 배터리의 전압이 불균형이 생길 때 포워드 컨버터가 작동하여 밸런싱을 맞추는 새로운 불연속모드 부스트-포워드 컨버터 토폴로지를 제안한다. 전압 불균형 에 따른 밸런싱 조건에 대한 식을 증명하였고, 실제로 80W급 하드웨어를 제작하여 제안된 회로를 검증하였다.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.3
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• pp.64-76
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• 2009

Adaptive Random Testing through Iterative Partitioning(IP-ART) is one of Adaptive Random Testing(ART) techniques. IP-ART uses an iterative partitioning method for input domain to improve the performances of early-versions of ART that have significant drawbacks in computation time. Another version of IP-ART, named with EIP-ART(IP-ART with Enlarged Input Domain), uses virtually enlarged input domain to remove the unevenly distributed parts near the boundary of the domain. EIP-ART could mitigate non-uniform test case distribution of IP-ART and achieve relatively high performances in a variety of input domain environments. The EIP-ART algorithm, however, have the drawback of higher computation time to generate test cases mainly due to the additional workload from enlarged input domain. For this reason, a revised version of IP-ART without input domain enlargement needs to improve the distribution of test cases to remove the additional time cost. We explore three smoothing algorithms which influence the distribution of test cases, and analyze to check if any performance improvements take place by them. The simulation results show that the algorithm of a restriction area management achieves better performance than other ones.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.1
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• pp.124-132
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• 2002

In this paper, we present a vision algorithm and method for input image improvement and preprocessing of dented and raised characters on the sidewall of tires. we define optical condition between reflect coefficient and reflectance by the physical vector calculate. On the contrary this work will recognize the engraved characters using the computer vision technique. Tire input images have all most same grey levels between the characters and backgrounds. The reflectance is little from a tire surface. therefore, it's very difficult segment the characters from the background. Moreover, one side of the character string is raised and the other is dented. So, the captured images are varied with the angle of camera and illumination. For optimum Input images, the angle between camera and illumination was found out to be with in 90$^{\circ}$. In addition, We used complex filtering with low-pass and high-pass band filters to improve input images, for clear input images. Finally we define equation reflect coefficient and reflectance. By doing this, we obtained good images of tires for pattern recognition.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.37 no.6
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• pp.70-75
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• 2000

This paper examines the performance of adaptive filtering algorithms in relation to the asymptotic relative efficiency (ARE) of estimators. The adaptive filtering algorithms are Hybrid II and modified zero forcing (MZF) algorithms. The Hybrid II and MZF algorithms are simplified forms of the LMS algorithm, which use the polarity of the input signal, and polarities of the error and input signals, respectively. The ARE of estimators for each algorithm is analyzed under the condition of the same convergence speed. Computer simulations for adaptive equalization are performed to check the validity of the theory. The explicit expressions for the ARE values of the Hybrid II and MZF algorithms are derived, and its results have similar values to the results of computer simulation. It also revealed that the ARE values depend on the correlation coefficients between input signal and error signal.

• Journal of the Korean Vacuum Society
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• v.9 no.4
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• pp.428-435
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• 2000

Negative ion generation in an inductively coupled oxygen plasma was investigated by using a Langmuir probe. It was observed that the probe current ratio of the positive ion saturation current and the negative current which is consisted of the electron current and the negative ion current, and also the potential difference between the floating potential and plasma potential vary with the RF input power and more sensitively with the operating pressure, respectively. Results show that the operating condition to achieve the maximum probe current ratio and the minimum potential difference shift from the low pressure region to the high pressure regions with increasing the input power. It implies that the generation of the negative oxygen ions increases and the recombination of the positive and negative ions are enhanced in the plasma.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.474-476
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• 2009

In the radio communication, such as echo cancellation and channel equalization, adaptive filtering is very practical. Its convergence behavior that is used for updating the weights depends on the correlation of the input signal and length of adaptive filter. Highly correlated input and long length of adaptive filter deteriorate the convergence behavior. To solve this problem, recently, subband affine projection algorithm which pre-whiten the correlation of the input and update the weights in subband structure has been presented. This paper presents convergence analysis method of multiple constrained subband affine projection algorithm.

• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.6
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• pp.476-486
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• 2008

It is very important to design the input filter optimally in matrix converters. But, the input power factor is deteriorated in spite of the optimal filter design due to the existence of inductor and capacitor included in the filter, and it is hard to keep high power factor in the whole operating range which is one of the major advantages of the matrix converters because the power factor is changed according to the output frequency and the load current. In this paper, we introduce the new space vector modulation method which can preserve the input power factor almost unity even though the output load or the output frequency is varied. It is also presented how to implement the proposed method effectively.

• Proceedings of the Korean Society of Computer Information Conference
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• 2009.01a
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• pp.237-240
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• 2009

감시 시스템은 지역의 특성에 따라 다양한 환경 및 설치 조건을 가지게 되며, 지능적 처리 요구에 따라 객체 분류를 필요로 한다. 본 논문에서는 검출된 객체로부터 특징 정보의 자율적 추출 및 학습을 이용하여 객체를 분류하기 위한 방안을 제시하고자 한다. 다양한 환경 및 설치 조건에서도 감시 시스템의 입력과 처리에 대한 추가적 보정 과정이 필요하지 않으며, 연속적으로 입력되는 객체의 형태와 움직임 정보를 효과적으로 활용하여 객체의 특징 추출 및 분류가 가능하게 된다.

• Proceedings of the KIEE Conference
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• 2003.11b
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• pp.7-10
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• 2003

뱀형 로봇은 자유도보다 액추에이터의 수가 적은 논홀로믹 구속조건(nonholonomic constraint)을 가지며, 단순한 신체구조 이지만 초-여유자유도 구속조건(hyper-redundant constraint)을 이용해서 기밀한 운동과 다양한 기능을 만들어내는 특징을 가지고 있다. 본 논문에서는 6개의 관절로 각 링크가 2차원 상에서 직렬로 연결된 뱀형 로봇의 기구설계 및 기구학과 동력학을 바탕으로 설계된 기구에 대해 해석하여 운동방정식을 유도하여 추진원리와 운동원리에 관하여 알아본다. 기본적인 운동 메커니즘을 해석하여 구현한 알고리즘을 제작한 로봇에 적용하여 추진 원리와 운동원리를 검증한다. 실험용 로봇은 링크 중앙에 법선 방향으로 마찰력이 발생할 수 있도록 수동바퀴를 가지고 있으며, PC와 RF(Radio Frequency)로 직렬통신을 하며 PC에서의 운동 명령의 조작에 의해 전진, 후진, 좌/우 방향으로 회전을 할 수 있도록 운동 알고리즘을 적용할 수 있도록 제작되었다. 특징으로는 일반적으로 토크를 입력으로 하지 않고 각도를 입력으로 하여 관절을 제어하고 있다는 점이 있으며, 운동방정식 또한 이에 대한 관계를 바탕으로 유도한 것이다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.05a
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• pp.336-337
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• 2010

본 연구는 현대자동차 무향 풍동(HAWT)에서 나온 실험치를 범용 CFD software인 SC/Tetra를 활용하여 모사하였다. 이를 위해서 우선 현대자동차 무향 풍동(HAWT)의 입력 경계층을 설정하고, grid test를 통해 최적의 격자를 찾고, 이에 맞는 난류 모델을 선정하였다. 입력 경계조건 설정, 격자 선정, 난류 모델 선정을 완료 후 나온 경계조건을 활용하여 실제 모델에 적용하여 현대 자동차 무향 풍동(HAWT)에서 나온 결과와 SC/Tetra에서 나온 결과와 비교 분석 하였다.