• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1640-1642
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• 2004

현재 국내에서의 견인전동기 개발현황은 직류전동기는 655kw, 교류전동기는 210kw정도이며, 주행속도가 200km/h이상인 고속에 적용되는 1,000kW급 이상 유도전동기 기술은 한국형 고속전철이 국내에서는 최초이다. 최고 주행속도 300km/h급의 고속전철용 1,130kW 동기전동기에 대한 제작 및 시험기술만을 프랑스에서 이전 받아 유도전동기를 제작하였다. 고속철도 차량용 견인전동기는 한정된 공간에 취부되어야 함으로 경량화가 필수적이다. 또한 전력기기에 대한 에너지 고밀도화가 가능해야 함으로 열적 특성에 대한 분석이 체계적으로 이루어져야 한다. 본 연구를 통해 외기 온도, 주행 속도 및 운행 시간에 따른 견인전동기의 온도 특성 변화를 살펴봄으로써 고속전철용 견인전동기의 고정자 온도 특성을 확인할 수 있었다.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1601-1603
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• 2005

현재 국내에서의 견인전동기 개발현황은 직류전동기는 655kW, 교류전동기는 210kW정도이며, 주행속도가 200km/h이상인 고속에 적용되는 1,000 kW급 이상 유도전동기 기술은 한국형 고속전철이 국내에서는 최초이다. 최고 주행속도 300km/h급의 고속전철용 1,130kW 동기전동기에 대한 제작 및 시험기술만을 프랑스에서 이전 받아 유도전동기를 제작하였다. 고속철도 차량용 견인전동기는 한정된 공간에 취부되어야 함으로 경량화가 필수적이다. 또한 전력기기에 대한 에너지 고밀도화가 가능해야 함으로 열적 특성에 대한 분석이 체계적으로 이루어져야 한다. 본 연구를 통해 외기 온도, 주행 속도 및 운행 시간에 따른 견인전동기의 온도 특성변화를 살펴봄으로써 고속전철용 견인전동기의 고정자 온도 특성을 확인할 수 있었다.

• Journal of Advanced Navigation Technology
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• v.14 no.3
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• pp.328-335
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• 2010

In this paper, an efficient algorithm and area-efficient hardware architecture have been proposed for $2{\times}2$ MIMO-OFDM based WLAN baseband modem with two transmit and two receive antennas. To enhance the performance of the receiver, the efficient timing synchronization algorithm and symbol detector based on MML algorithm are presented. Also, by sharing the hardware block with multi-stage pipeline structure and using the complex multiplier based on polar-coordinate, the complexity of the proposed architecture is dramatically decreased. The proposed area-efficient hardware design was designed in hardware description language (HDL) and synthesized to gate-level circuits using 0.13um CMOS standard cell library. As a result, the complexity of the proposed modem receiver is reduced by 56% over the conventional architecture.

• Information Systems Review
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• v.9 no.3
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• pp.133-156
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• 2007

The wide spread of the Internet and personal computers does not only alter the form of content from analog to digital, but also lead to the emergence of a new digital media system that is different from analog media system. The digital media system is a convergent media that includes both public and private systems from the perspective of use-limitation, as well as storage and enjoyment systems from the perspective of use-purpose. The major goal of this research is to suggest and empirically verify an effective way of presenting the perception of places that are converged in the digital media system. Involvement and motivation are suggested as key conceptual factors and color contrast and hue are suggested as concrete design factors to make people perceive corresponding places. Results of our controlled experiment indicated that the color contrast and hue significantly affected the perception of place, and consequently, influenced usability of the digital media system. This paper ends with implications that can be used to construct appropriate perception of places for the media system of digital products.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.688-695
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• 2017

This paper deals with characteristics analysis of a permanent magnet (PM) linear generator using analytical methods for wave energy harvesting. The wave energy is carried out from the movement of a yo-yo system. A linear generator using permanent magnets to generate a magnetic force itself does not require a separate power supply and has the advantage of simple maintenance. In addition to the use of a rare earth, a permanent magnet having a high-energy density can be miniaturized and lightweight, and can obtain high energy-conversion efficiency. We derived magnetic field solutions produced by the permanent magnet and armature reaction based on 2D polar coordinates and magnetic vector potential. Induced voltage is obtained via arbitrary sinusoidal input. In addition, electrical parameters are obtained, such as back-EMF constant, resistance, and self- and mutual-winding inductances. The space harmonic method used in this paper is confirmed by comparing it with finite element method (FEM) results. These facilitate the characterization of the PM-type linear generator and provide a basis for comparative studies, design optimization, and machine dynamic modeling.

• The Korean Journal of Nuclear Medicine Technology
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• v.20 no.1
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• pp.20-23
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• 2016

Purpose Because of heart movement, PET image of heart is very blur. So, PET scan gated with ECG is necessary to improve a spatial resolution of heart PET image. In this study, we will evaluate a image quality of both gated $^{13}N-ammonia$ PET scan and non-gated one. Materials and Methods Before start a heart PET, we attached a ECG electrode on patients (n = 5, $aged=54{\pm}17$). And we started a list mode PET scan that used by a mCT40 PET/CT (siemens, germany) during 10 minute, injected $^{13}N-ammonia$ ($378{\pm}50MBq$) to a patients at same time. By using this list mode data, we reconstructed both gated PET image and non-gated PET image. Then we analysed a profiles of those images, performed a blind test, and subtracted a gated image on non-gated image. Results FWHM of a gated image is improved about 23% and there is a differency count distribution at a subtracted image from non-gated image to a gated image. But in case of blind test, everybody select the gated image as a better quality among each images. Conclusion As a result, we can find that image quality will improve by using gated PET scan. In additional, we can calculate a EF valve, apply QGS, QPS of PET. Therefore, the gated PET scan help improving an accuracy, applying a more information for a diagnosis.

• Journal of the Korean Institute of Intelligent Systems
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• v.24 no.1
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• pp.52-57
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• 2014

This paper presents an implementation of a smooth path planning method considering physical limits on a real time operating system for a two-wheel mobile robot. A Bezier curve is utilized to make a smooth path considering a robot's position and direction angle through the defined path. A convolution operator is used to generate the center velocity trajectory to travel the distance of the planned path while satisfying the physical limits. The joint space velocity is computed to drive the two-wheel mobile robot from the center velocity. Trajectory planning, velocity command according to the planned trajectory, and monitoring of encoder data are implemented with a multi-tasking system. And the synchronization of tasks is performed with a real-time mechanism of Event Flag. A real time system with multi-tasks is implemented and the result is compared with a non-real-time system in terms of path tracking to the designed path. The result shows the usefulness of a real-time multi-tasking system to the control system which requires real-time features.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.3A
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• pp.337-344
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• 2006

In this paper, we propose a multi-view video codec for 3DTV system. The proposed algorithm is not only to reduce the temporal and spatial redundancy but also to reduce the redundancy among each view. With these results, we can improve the coding efficiency for multi-view video sequences. In order to reduce the redundancy of each view more efficiently, we define the assembled image(AI) that is generated by the global disparity compensation of each view. In addition, the proposed algorithm is based on MPEG-2 structure so that we can easily implement 3DTV system without changing the conventional 2D digital TV system. Experimental results show that the proposed algorithm performs very well. It also performs better than MPEG-2 simulcast coding method. The newly proposed codec also supports the view scalability, accurate temporal synchronization among multiple views and random access capability in view dimension.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.4
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• pp.767-773
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• 2000

As computer systems and communication technologies develop rapidly, CSCW(Computer Supported Collaborative Work) system appears nowadays, through which it is available to work on virtual space without any restriction of time and place. Most of CWCS systems depend on a special network and groupware. The systems of graphics and CAD are not so many because they are specified by hardware and application software. In this paper, we propose a web-based collaborative CAD system, which can be jointly worked on Internet WWW being independent from any platforms. It can create and modify 3D objects easily using VRML and Java 3D API, and it can send, print, and store them. The interactive work for designing objects can be also carried out through chatting with each other. This system is executed in the environment of Client/server architecture. Clients connect to the CAD sewer through Java applet on WWW. The server is implemented by Java application, and it consists of three components : connection manager which controls the contact to users, work manager which keeps viewing in concurrency and provides virtual work space sharing with others, and solid modeler which creates 3D object.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.3
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• pp.153-158
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• 2017

With the fast increment of fusion ICT(Information and Communication Technology), new creative tourism model is required for the revival of local economy. We come up with new frame that is able to increase tourists and revive local economy through ICT fusion such as spatial informaion, contents, game, smart phone, wearable device and wireless internet. In this paper, we propose 'Gamified Tourtainment Service Platform' that can be provided tourists with user custom tour guidance and gamified tour services for motivation, fun, contest, reward in the environment of outdoor. This platform is a kind of framework for creating and providing gamified creative tour services and a gateway for increasing tourist and reviving commercial local economy. We also propose the real tourtainment service application that is implemented with this platform and smart phone.