• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.5
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• pp.329-335
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• 2008

Recently, super high-speed motor drives have been available due to the development of power electronics technology And they are used in various fields of industry because of their advantages. This paper describes the control algorithm for a permanent magnet synchronous motor(PMSM) drive at the speed of 118,000r/min using DSP and IGBT inverter. Hall sensors are implemented to measure the rotor position and speed, and a speed observer is used to reduce the performance deterioration caused by the low resolution of hall sensors. To enhance the output power capacity in the high-speed operating region, a flux weakening controller which also can work as an anti-wind up controller is used. Computer simulations and experiments are peformed to validate the proposed method.

• Journal of the Korean Institute of Telematics and Electronics
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• v.19 no.5
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• pp.55-67
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• 1982

In this Paper new results relating to the acquisition behavior of a class of first-and secondorder digital phase-locked loops (DPLL) originally proposed by Reddy and Cupta are presented in the absence of noise. It has been found that the number of quantization levels L and the number of phase error states N play important roles in acquisition. For a given L-level quantizer, as N increases, the acquisition time increases, and the lock range decreases. However, the deviation of the steady state phase error decreases in this case. When L increases, the acquisition time decreases, and the lock range increases. However, variation of L affects little for the steady state phase error. In addition, the effects of a loop filter on acquisition have also been considered. One can get smaller acquisition time and larger lock range as the filter parameter value becomes larger. However, deviation of the steady state phase error increases in that case. Analytical results have been verified by computer simulation.

• Archives of design research
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• v.16 no.3
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• pp.59-70
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• 2003

The consumer's feelings toward products is each evaluated and appears in different way that is to say there are various types of motives for deciding a purchase for example, there might be an interesting function and emotional reaction. How is the product image that induces motives like this metaphorized and evaluated to be existing in the mental image. This study inquired into, it by presenting problems conscious of both sides indicated above, the major points associated with image of the product, characteristic positions of product elements and evaluation of the product. To draw out a clear conclusion, first three hypotheses were established and case a study was performed as part of conclusive research for verification of this. The collected data was made, by simple tabulation to represent the overall flow, and based on this, concrete analysis was conducted on the three reserch items. The analysis method weighted on quantitative analysis with consideration to consumer's psychological aspect. As the result, three important conclusions could be drawn out or ratiocination for evaluation of mental image formation.

• Journal of Broadcast Engineering
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• v.1 no.2
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• pp.85-95
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• 1996

The purpose of this paper Is to propose a dubbed signal time-synchroniztion technique based on the SOLA(Synchronized Over-Lap and Add) method which has been widely used to modify the time scale of speech signal. In broadcasting audio recording environments, the high degree of background noise requires dubbing process. Since the time difference between the original and the dubbed signal ranges about 200mili seconds, process is required to make the dubbed signal synchronize to the corresponding image. The proposed method finds he starting point of the dubbing signal using the short-time energy of the two signals. Thereafter, LPC cepstrum analysis and DTW(Dynamic Time Warping) process are applied to synchronize phoneme positions of the two signals. After determining the matched point by the minimum mean square error between orignal and dubbed LPC cepstrums, the SOLA method is applied to the dubbed signal, to maintain the consistency of the corresponding phase. Effectiveness of proposed method is verified by comparing the waveforms and the spectrograms of the original and the time synchronized dubbing signal.

• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.2
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• pp.168-175
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• 2009

This paper proposes an enhanced algorithm for sensorless control of 45,000rpm/22kw type Permanent Magnetic Synchronous Motor (PMSM) with air-foil bearing. The proposed algorithm is based on iterative adaptive flux observer for sensorless control of the motor in wide speed range by on-line estimating angle and velocity of rotor. Simulation error between actual and estimated angle of rotor is analyzed to enhance characteristics of frequency response of conventional adaptive flux observer, which results in stable response in wide range of speed. Using the iteration number for stable phase-delay characteristics, the observer enhances the dynamic characteristics of the observer within current control period. The experiment results show the reliable performance of the proposed algorithm through starting to high speed operating range.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.5C
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• pp.519-533
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• 2006

The number of channels specified in IEEE 802.15.4 Low-Rate Wireless Personal Area Networks(LRWPANs) is too few to operate many applications of WPANs in the same area. To overcome this limit, we introduce Virtual Channel, a novel concept to increase the number of available channels when various WPAN applications coexist. Basically, a virtual channel is a newly-created channel via superframe scheduling within the inactive period of a logical channel preoccupied by other WPANs. To maximize the coexistence capability of WPANs using virtual channels, we propose Least Collision superframe scheduler(LC-scheduler), its less complex heuristics both for a given single channel, and Virtual Channel Selector(VCS) to efficiently manage multiple available logical channels. In addition, a simple but practical synchronization method is developed to compensate different time drifts among coexisting WPANs. The simulation results demonstrate that a remarkable improvement on the coexistence capability of the 802.15.4 can be achieved through the proposed schemes.

• Journal of Digital Convergence
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• v.15 no.3
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• pp.195-200
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• 2017

The purpose of this study is to provide a virtual CG - based image production system for a simulator camera. The video production system proposed in this study is designed to synchronize the virtual camera of the graphic tool with the simulator camera at the shooting site and the CG application image editing, And can be easily and easily performed through a graphic tool by being controlled virtually through a control interface. Blaze Knights, an animation created by Dongseo University, was used to illustrate the superiority of the research results by comparing the progress and the amount of work before and after the application of the system. According to the results of the research, the CG artist's work efficiency is increased, while the physical constraint is minimized when the scene of the CG application image is minimized. It is possible to produce various scenes and minimize the re- We expect the contribution to the industry to be high.

• Journal of Convergence for Information Technology
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• v.7 no.6
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• pp.209-218
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• 2017

To propose a contents model for children's smart watch, this study interview 15mothers who have a child using smart watches. Most mothers purchase smart watches for children to warrant their security and manage their schedules, and they use them for sending a call or text to their children, tracking or managing children's location and schedule. Mothers were satisfied with a smart watch's function of communication and safety management, but dissatisfied learning-oriented contents and worrried about bad influenced on children development. Through in-depth interviews, this study propose a persona model for children's smart watch for enhancing parent-child interaction and physical cognitive language socioemotional convergence play contents.

• Journal of KIISE:Information Networking
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• v.29 no.1
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• pp.97-107
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• 2002

In general, under interactive broadcasting environment, user finds additional service using top-down menu. However, user can't know that additional service provides information until retrieval has finished and top-down menu requires multi-level retrieval. This paper proposes the new method for additional service providing not using top-down menu but using object selection. For the purpose of this method, the movie of a MPEG should be synchronized with the object information(position, size, shape) and object tracking technique is required. Synchronization technique uses the Directshow provided by the Microsoft. Object tracking techniques use a motion-based tracking and a model-based tracking together. We divide object into two parts. One is face and the other is substance. Face tracking uses model-based tracking and Substance uses motion-based tracking base on the block matching algorithm. To improve precise tracking, motion-based tracking apply the temporal prediction search algorithm and model-based tracking apply the face model which merge ellipse model and color model.

• Journal of the Korean Society of Clothing and Textiles
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• v.25 no.10
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• pp.1719-1727
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• 2001

본 연구는 심리적으로 불안정하여 준거집단이나 사회의 영향을 민감하게 받으며, 의복과 외모에 관심이 높은 청소년을 대상으로 전통적 가치관이 무너지고 소비 지향적인 물질주의 가치관이 팽배한 사회 분위기 속에 이들의 심리적 변수인 가치관이 의복행동에 영향을 미치는 지를 알아보고자 하였다. 연구방법은 서울의 강남과 강북에 위치한 고등학교 1학년 남녀 학생 530명을 대상으로 선행연구에서 사용된 척도를 사용한 실증연구를 하였다. 자료 분석은 SPSS/PC$^{+}$프로그램을 사용하여 t-test, ANOVA, MANOVA등을 실시하였다. 연구결과, 물질주의 가치관은 청소년의 의복착용행동에 영향을 미쳐, 물질주의 가치관이 높은 청소년은 물질주의 가치관이 낮은 청소년에 비해 의복 착용시 심미성을 더 중시하고 의복에 대한 관심과 의존도가 높으며, 의복을 또래집단과 비슷하게 입으려는 동조성도 더 높았으며 의복을 통해 과시하려는 경 향도 높았다. 그러나 의복착용시 정숙성은 그리 중요하게 생각하지 않았다. 물질주의 가치관은 청소년이 의복을 구매할 때도 영향을 미쳐, 물질주의 가치관이 높은 청소년의 의복구매동기는 물질주의 가치관이 낮은 청소년에 비해 더 충동적이고 과시적이며, 유행과 개성 지향적인 것을 알 수 있었으나 실질적이거나 실용적인 구매동기는 상대적으로 약한 것으로 나타났다. 물질주의 가치관에 따라 청소년의 의복 구매시 사용하는 정보원천과 즐겨 구매하는 장소도 차이가 나타나, 물질주의 가치관이 높은 청소년이 물질주의 가치관이 낮은 청소년보다 의복 구매시 정보를 얻기 위해 더 많은 정보원천을 사용하며, 다양한 구매장소를 활용하며, 더 비싼 의류제품을, 더 자주 구매하며, 쇼핑을 위해서도 더 많은 시간을 할애하는 것으로 나타났다. 이와 같은 결과로 청소년의 물질주의 가치관은 이들의 의복관심과 의복착용 그리고 구매에 지대한 영향을 미친다는 것을 알 수 있다.