• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.5
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• pp.36-42
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• 2003

This paper presents a new current-source PWM inverter based on Buck-boost configuration to interface between photovoltaic system and utility line. Proposed inverter is consisted by two set of buck-boost topology, and the input inductor is designed to be operated on the discontinuous current conduction mode. So high power factor can be achieved without additional input CtUTent controller. As a result, overall system has simple structure, and it can obtain higher ac output rms voltage than the terminal voltage of the photovoltaic system without additional boosting procedure. The operational modes are theoretically analyzed, and then the validity of the proposed system was verified through simulation and experimental results using a prototype.

• The Journal of the Korea Contents Association
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• v.10 no.3
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• pp.1-9
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• 2010

In this paper, we propose a new method of improving accuracy of motion estimation in mobile environments, compared with Rosten's algorithm. The present method selects corners as feature points. The Rosten's algorithm uses simple addition and subtraction to detect the corners. Although it has the advantage of faster processing speed, Rosten's algorithm has a drawback of low performance in motion estimation. We use the NCC(Normalized Cross Correlation) coefficients to match the corners, and remove in two steps the outliers of inaccurate matching corners. We compare the proposed algorithm with Rosten's algorithm by applying both to the real images. We find that the proposed method shows better performance than Rosten's algorithm in motion estimation. In addition, we implement the present method on mobile devices and confirm that it works in mobile environments in real time.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.7
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• pp.1416-1427
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• 2012

This paper proposes a design technique of a survivable ship backbone network, which describes a near optimal configuration scheme of physical and logical topologies of which the survivable ship backbone network consists. We first analyze and present an efficient architecture of a survivable ship backbone network consisting of redundant links and ship devices with dual communication interfaces. Then, we present an integer linear programming-based configuration scheme of a physical topology with regard to the proposed ship backbone network architecture. Finally, we present a metaheuristic-based configuration scheme of a logical topology, underlying the physical topology.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.1
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• pp.50-57
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• 2004

Two processors are generally used to drive the power circuits for controlling the dual motors independently. In this paper, we propose the new control scheme to drive dual inverters using only one controller with the aid of CAN network. The proposed system is very useful compared to conventional techniques especially in case of controlling the combined dual motors because the control algorithm can be implemented by the software program only without any additional processor or hardware interfacing. The proposed system is implemented and verified experimentally.

• The KIPS Transactions:PartD
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• v.12D no.1 s.97
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• pp.159-164
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• 2005

In a computing environment connected pan-based computers and a server by Internet, This paper describes a language learning system evaluating the quality of a handwriting string. For the purpose of the system, this paper explains how to retrieve reference data from a database, how to evaluate the quality of a handwriting string using global and local features. The Proposed system can evaluate the qualify of a handwriting string as well as a handwriting character. The qualify can be computed in the case of different language between reference and input. Therefore, we expect that the system is very useful not only for training on handwriting but also learning a language.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.10
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• pp.4550-4560
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• 2011

Generally, a optical encoder is used to detect velocity for controling the electronic motor, the resolver is used when it is hard structurally to adjust encoder to electronic motor. so, the resolver has weakness in price in compare with encoder, but in case of controling the position of a magnetic polar, the resolver has stead detecting the absolute position of a rotator. This study is about the digital programing velocity detector which uses a minimum hardware : filter for detecting the revolve speed and rotor position of the motor by means of the resolver.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.05a
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• pp.1671-1674
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• 2005

PCI 2.2 마스터 디바이스가 타겟 디바이스로부터 데이터를 읽어 오고자 할 때 타겟 장치는 내부적으로 데이터를 준비해야 함으로 인해 PCI 버스가 데이터 전송 없이 점유되는 상황이 발생한다. 이를 위해 PCI 2.2 사양에서는 지연전송을 제안하여 전송 효율을 향상시켰지만 이 역시 타겟 디바이스가 얼마의 데이터를 미리 준비 해둘지를 알 수 없어 인해 버스 사용 및 데이터 전송 효율을 떨어뜨리는 원인을 제공한다. 본 논문에서는 먼저 이를 해결하기 위한 새로운 방법을 제안한다. 그리고 이 방법을 지원하는 PCI 타겟 컨트롤러와 로컬 디바이스를 설계하였다. 설계되어진 PCI 타겟 컨트롤러는 PCI 2.2를 전혀 모르는 사용자도 쉽게 PCI 인터페이스를 지원할 수 있도록 한 프로토콜 변환기로 사용될 수 있다. PCI 타겟 컨트롤러와 로컬 디바이스는 먼저 행위 모델로 설계하였으며 또한 이들을 검증하기 위한 테스트벤치를 설계 하였다. 이를 통해 제안되어진 방법의 성능을 측정하였으며 후에 다시 실제 하드웨어로 설계하였다. 설계되어진 하드웨어를 효과적으로 검증하기 위해 참조모델, 랜덤발생기, 비교엔진으로 구성된 랜덤 테스트 환경을 제안하였다. 이 검증 환경에서 수행된 결과를 비교함으로써 일반적인 테스트 벡터에서 발견하기 어려운 에러들을 발견할 수 있었다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.4A
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• pp.309-315
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• 2009

Wireless Ad-hoc networks are dynamic networks that consist of mobile nodes. Nodes in Ad-hoc networks are usually laptops, PDAs or mobile phones. These devices feature Bluetooth and/or IEEE 802.11 (WiFi) network interfaces and communicate in a decentralized manner. Due to characteristics of Ad-hoc networks, Mobility is a key feature of routing protocol design. In this paper, we present an enhanced routing maintenance scheme that cope with topology changes pre-actively. The key feature of the proposed scheme is to switch next-hop node to alternative neighbor node before link breakage for preventing route failure. From extensive experiments by using NS2, the performance of the proposed scheme has been improved by comparison to AODV protocol.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.6
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• pp.67-74
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• 2006

In this paper, a tiled display system is developed to get a high-resolution image in visualization of large-scale structural analysis data with low-resolution display devices and low-cost cluster computer system. Concerning the hardware system, some of the crucial points are investigated, and a new beam-projector positioner is designed and manufactured to resolve the keystone phenomena which result in distorted image. In the development of tiled display software, Qt and OpenGL are utilized for GUI and rendering, respectively. To obtain the entire tiled image, LAM-MPI is utilized to synchronize the several sub-images produced from each cluster computer node.

• Science of Emotion and Sensibility
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• v.5 no.2
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• pp.35-50
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• 2002

The purpose of this research is 1) to search for the possibility of DMDI(Digitalwear based on motion-detective input technology) as an apparel product and 2) to develop designs of DMDI based on consumers' demand. This research consists of part I and part Ⅱ. In partⅠ, six design guidelines for designing of DMDI and five feasible applications were suggested as the result of an empirical study. In part Ⅱ of this research, two basic directions for designing of DMDI were suggested on the basis of the findings in part Ⅰ. Total 5 design prototypes of DMDI were developed, for which ‘wearability as an apparel product’ and ‘usability as an physical interface’ were intensively considered.