• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2003.05a
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• pp.66-72
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• 2003

The paper describes on the implementation of three-dimensional visualization system that is to visualize meaning of the statistical prediction results of marine casualty with easy of understanding. Graphical User Interface(GUI) and Web based Virtual Reality (VR) technology are mainly introduced in the system development. In addition, the time based prediction models of the marine casualty and the risk level are developed to display daily situation. As operating test results of the system, it is known that complicated statistical results can be shown as simple colour in the three-dimensional virtual space.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2009.10a
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• pp.187-188
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• 2009

On this study, the artificial neural network, one of the nonlinear forecasting methods, is compared with ARIMA model through performing a forecast of container traffic. The existing studies have been used the rule of thumb in topology design for network which had a great effect on forecasting performance of the artificial neural network. However, this study applied the genetic algorithm, known as the effectively optimal algorithm in the huge and complex sample space, as the alternative.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.6
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• pp.550-559
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• 2005

The matrix converter provides sinusoidal input and output wave forms, bidirectional power flow, controllable input power factor and a long life, compared to the VSI(Voltage Source Inverter) with diode rectification stage at the input. However it has tasks, such as complexity of the control method, ride-through problem and low voltage-ratio limitation, to overcome for commercializing, This paper describes the design, construction and implementation of matrix converter based on space vector modulation technique. The implemented prototype of matrix converter is built using the exclusive IGBT module and control circuit constituted with DSP and CPLD and it has an input filter, overvoltage protection circuit and commutation means for overcoming practical issues. The good results tested using an induction motor are also presented.

• Annual Conference of KIPS
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• 2006.11a
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• pp.223-226
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• 2006

가상현실 기술은 3 차원 가상공간 및 물체를 시각화하는데 중점을 두고 있다. 이는 사용자가 3 차원으로 데이터를 충분히 활용하지 못하고, 시각자료로만 사용하게 되는 요인이 된다. 이를 보완하기 위해 시각 정보뿐만 아니라 구조 및 관계에 대한 정보까지도 효과적으로 활용 할 수 있는 연구가 필요하다. 따라서 본 연구에서는 외형뿐만 아니라 내부적인 구조와 관계에도 의미를 부여하기 위하여 3 차원 건축물에 XML 기반의 토픽맵을 적용하였다. 전통 건축물의 공포 부분을 모델링하고, 각각의 객체가 사용자에 의해 조작이 가능하도록 하였으며, 객체들의 구조와 연결관계를 분석하고, 정의된 구조 및 관계를 토대로 토픽맵을 작성하였다. 작성된 토픽맵은 모델링 데이터에 적용 가능하도록 DOM 을 이용하여 변환하였다. 이 연구를 통해 아무리 복잡한 구조물이라도 그에 대한 구조 정보를 쉽게 파악할 수 있었고, 계층적 연결 관계도 쉽게 파악 할 수 있었다.

• KIPS Transactions on Computer and Communication Systems
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• v.1 no.3
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• pp.151-160
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• 2012

In this paper, a database method for Wind Power Plant SCADA system based on IEC61400-25 was designed. To manage big data, which is produced by the introduction of international standards and large/grouping of wind power plant, database should be systematically designed. As identify the characteristics of the wind power data and reflect the requirements of a user, it would be decreasing the waste of data space and managing efficiently the system. As a result, it is expected to reduce cost and effort in development and maintenance of Wind Power Plant.

• The KIPS Transactions:PartB
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• v.12B no.7 s.103
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• pp.767-774
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• 2005

In this paper, we present a snake-based scheme for tracking object contour using disparity information taken from a stereo image sequence with cluttered background. The proposed method is composed of two steps. First, 3-D motion of object is estimated and candidate snake points are selected in disparity space. Second, object contour is extracted by using a modified snake algorithm with disparity information. The proposed algorithm can successfully extract the concave contour of objects and track the object contour in complex image. Performance of the proposed algorithm has been verified by simulation.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2390-2392
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• 2003

ILC(Iterative Learning Control: 이하 ILC)는 현재 기계, 전기, 화학 등 많은 분야에 널리 적용되고 있다. ILC는 특히 반복적인 trajectory tracking Control 문제에 아주 효과적인 방법 중의 하나이다. 하지만 ILC는 메모리 기반의 scheme로서 trajectory tracking을 위해서는 많은 메모리를 요구하게 된다. 한편, 자세한 관찰에 의하면 인간의 팔, 다리 등의 관절의 움직임은 아주 정확하지가 않다. 이러한 사실로 미루어 인간이 정화한 모션을 취하는데 드는 비용을 줄이고자 모션 명령을 간단히 한다는 가정을 추론 해 낼 수 있다. 이러한 가정에 기초하여 우리는 ILC 명령을 간단히 하기 위해서 약간의 trajectory tracking의 정확성을 회생하는 메커니즘을 제안한다. 간단해진 ILC 명령은 적은 메모리 공간에 저장될 것이다. 또한, 로봇의 trajectory tracking을 위한 기존의 방법들은 아주 복잡할 뿐만 아니라 하나의 task의 수행만이 가능할 뿐 어떤 일반화의 방법도 제시하지 못하고 있다. 그래서 본 논문에서는 ILC 명령의 scaling에 대한 메커니즘을 제공하여 하나의 trajectory에 대해서 비슷한 모양이지만 다른 크기와 속도를 가지는 trajectory를 구현 할 수 있도록 하였다.

• Archives of design research
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• v.17 no.1
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• pp.299-308
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• 2004

The methods of presenting information are more variable with advanced computer media technology. However, when we visualize information of database, it is more difficult to understand data meaning by complex date, which is not required by user. To compose new information, user needs to combine own his memory and new information presenting result. To be quickly explored new information and be exactly understood relationship of data structure, the data presenting of visualized information is more structured and presented with meaning form. It is possible to make information visualization system, which users can explore database by oneself, with supporting interaction to be able to control and combine relationship of three-dimensional scene graphic structure, presenting factors of animation and data structure of database. There are several diagrams, such as VR diagram, Form structure diagram and simulated diagram as the case study.

• Journal of KIISE:Computer Systems and Theory
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• v.34 no.4
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• pp.132-137
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• 2007

A point-wise car-like robot moving in the plane changes its direction with a constraint on turning curvature. In this paper, we consider the problem of computing a shortest path of bounded curvature between a prescribed initial configuration (position and orientation) and a polygonal goal, and propose a new geometric proof showing that the shortest path is either of type CC or CS (or their substring), where C specifies a non-degenerate circular arc and S specifies a non-degenerate straight line segment. Based on the geometric property of the shortest path, the shortest path from a configuration to a polygonal goal can be computed in linear time.

• Journal of KIISE:Computing Practices and Letters
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• v.11 no.6
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• pp.477-487
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• 2005

As embedded system grows in size and complexity, the importance of the technique for dynamic memory allocation has increased. The objective of this paper is to measure the performance of dynamic memory allocation by varying both hardware and software design parameters for embedded systems. Unlike torrent performance evaluation studies that have presumed the single threaded system with single address spate without OS support, our study adopts realistic environment where the embedded system runs on Linux OS. This paper contains the experimental performance analyses of dynamic memory allocation method by investigating the effects of each software layer and some hardware design parameters. Our quantitative results tan be used to help system designers design high performance, low power embedded systems.