• The Journal of the Acoustical Society of Korea
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• v.20 no.4
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• pp.22-28
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• 2001

This paper describes the implementation of a robust speaker position location system using the voice signal received by microphone array. To be robust to the reverberation which is the major factor of the performance degradation, low-frequency phase restoration algorithm which eliminates the influence of reverberations using the low-frequency information of the CPSP function is proposed. The implemented real-time system consists of a general purpose DSP (TMS320C31 of Texas instruments), analog part which contains amplifiers and filters, and digital part which is composed of the external memory and 12-bit A/D converter. In the real conference room environment, the implemented system that was constructed by the proposed algorithms showed better performance than the conventional system. The error of the TDOA estimation reduced more than 15 samples.

• Journal of the Korean Geotechnical Society
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• v.19 no.2
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• pp.107-121
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• 2003

When the seismic stability of quay walls is analyzed, the magnitudes of force components acting on quay walls during earthquakes and the phase relations among these force components must be properly evaluated. In general, force components include inertia force of the quay wall, lateral earth force, and water force. The magnitude and the phase relation of each force component vary according to the magnitude of the excess pore pressures developed in backfill soils of the quay wall. The dynamic thrust mobilized at the contact surface between the backfill soil and the wall develops as a result of the interactions among these force components. We propose a simple model to evaluate the magnitude and phase variation of the dynamic thrust on the back of the wall in terms of the excess pore pressure. The proposed model can predict the dynamic thrust by summing the magnitudes of farce components calculated from design equations for seismic pressures on the wall. The proposed model was verified by comparing its results with the results from a series of shaking table tests.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10d
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• pp.441-444
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• 2006

통신기술의 급격한 발전, 유비쿼터스에 대한 시장수요 증가, 신규 시장창출을 위한 비즈니스 전략이 결집되어 유무선 융합의 패러다임이 전개되고 있으며 유선의 전송속도와 무선의 이동성을 결합한 와이브로는 유무선 융합을 주도할 서비스로 부각되고 있다. 2006년 상반기에 상용화 될 예정인 와이브로가 안정적인 가입자 기반으로 조기에 시장확산을 이루기 위해서는 동시기에 출시될 HSDPA에 비하여 차별적 지위를 확보하고 기존 서비스와의 관계를 정립하기 위한 포지셔닝 전략이 요구된다. 이에 본 연구에서는 소비자 설문조사를 통해 와이브로의 시장수요를 HSDPA와의 관계 분석을 바탕으로 전망하며 기존 서비스와의 대체 또는 보완 관계를 파악하여 와이브로의 시장위상을 예측하였다. 분석결과 첫째, 잠재적 이용자가 인식하는 와이브로의 서비스 역량은 HSDPA에 비하여 전송속도와 이용요금에서 차별적 우위를 나타냈으며 둘째, 와이브로는 HSDPA에 비하여 가입자 규모에서 상대적인 우위를 보였으며 두 서비스의 가입 영향요인은 상이하였다. 마지막으로 와이브로는 초고속인터넷과는 보완 관계를, 이동전화 무선인터넷과 공중 무선랜과는 대체 관계를 형성하는 것으로 나타났다.

• 한국전기화학회:학술대회논문집
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• 1999.10a
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• pp.19-19
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• 1999

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.3
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• pp.427-437
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• 2008

In order to increase the coupling efficiency of the power and phase of the active phase array antenna, we have fabricated the active phased-array antenna which is coupled by the transmission line, and investigated the relationship between the length of the coupling transmission line and coupling power and phase. The following three types of driving method - (1) giving the frequency difference between the two active antenna, (2) applying the input signal to the one side of the two antennas, and changing the eigen frequency of the other side antenna, (3) appling the different phase inputs to the active antennas was investigated. The experimental results showed that the interval of the antenna elements has not affected the power and the phase of the antenna.

• Journal of KIISE:Software and Applications
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• v.37 no.3
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• pp.194-204
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• 2010

A space, real or virtual, comprises regions as its parts and physical objects residing in them. A coherent and sophisticated representaion scheme for their spatial relations premises the precision and plausibility in its associated agents' inferencing on the spatial relations and the development of events occurring in such a space. The existing spatial models are not suitable for a comprehensive representation of the general spatial relations in that they have limited expressive powers based on the dichotomy between the large and small scales, or support only a small set of topological relations. The representaion model we propose has the following distinctive chracteristics: firstly, our model provides a comprehensive representation scheme to accommodate large and small scale spaces in an integrated fashion; secondly, our model greatly elaborated the spatial relations among the small-scale objects based on their contact relations and the compositional relations among their respective components objects beyond the basic topological relations like disjoint and touch; thirdly, our model further diversifies the types of supported relations by adding the container property besides the soildness together with considering the gravity direction. The resulting integrated spatial knowledge representation scheme considering the gravity allows the diverse spatial relations in the real world to be simulated in a precise manner in relation to the associated spatial events and provides an expression measure for the agents in such a cyber-world to capture the spatial knowledge to be used for recognizing the situations in the spatial aspects.

• Spatial Information Research
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• v.18 no.5
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• pp.93-105
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• 2010

Spatial neighborhoods are spaces which are relate to target space. A 3D spatial query which is a function for searching spatial neighborhoods is a significant function in spatial analysis. Various methodologies have been proposed in related these studies, this study suggests an adjacent based methodology. The methodology of this paper implements topological data for represent a adjacency via using network based topological data model, then apply modifiable Dijkstra's algorithm to each topological data. Results of ordering analysis about an adjacent space from a target space were visualized and considered ways to take advantage of. Object of this paper is to implement a 3D spatial query for searching a target space with a adjacent relationship in 3D space. And purposes of this study are to 1)generate adjacency based 3D network data via network based topological data model and to 2)implement a 3D spatial query for searching spatial neighborhoods by applying Dijkstra's algorithms to these data.

• Proceedings of the Optical Society of Korea Conference
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• 2009.02a
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• pp.317-318
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• 2009

SPDC 를 이용한 Ghost imaging에서 signal과 idler 사이의 공간적 상관관계가 Fractional Fourier Transformation으로 알려진 관계를 따르며 이를 이용해 위상공간에서의 EPR 상태의 특성을 실험으로 구현할 수 있음을 보이려 한다. 또한 고전적인 경우와의 차이를 보이려 한다.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1374-1375
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• 2008

본 논문은 3상 일괄형 GIS의 부분방전 진단을 위해 새롭게 개발한 진단 알고리즘에 관한 것이다. 진단 알고리즘 개발을 위해, 먼저 실시간 부분방전 데이터를 행벡터 및 열벡터로 구성하고 각각의 벡터에서 통계 특징량 및 질감 특징량을 추출하였다. 다음으로 이들 특징량을 GA-NN(Genetic Algorithm - Neural Network) 학습에 적용하여 진단 알고리즘을 구성하였다. 또한 진단 알고리즘의 위상독립성은 부분방전 신호의 위상변화에 관계없이 진단결과가 일치하는 것을 확인함으로써 검증하였다. 개발한 진단알고리즘의 실증 평가를 위해, 부분방전이 발생되고 있는 국내 3상 일괄형 GIS 변전소에 적용하였다. 적용 결과, 위상에 관계없이 부분방전 발생원을 정확히 진단함을 확인하였고, 이를 통해 개발 알고리즘의 우수성을 입증하였다.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1063-1064
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• 2006

본 논문에서는 곡선구간에서도 구동이 가능한 선형 전동기 제어방법을 제안하였다. 곡선구간에 선형 전동기를 적용할 때 전동기의 고정자와 이동자의 기구적인 위치 상호관계에 의해 각 상의 위상관계는 직선구간과 다르게 나타나게 된다. 따라서 직선구간의 제어방법을 그대로 곡선구간에 적용 시 제어성능이 저하되어 전동기의 발생추력은 감소하게 되고, 최악의 경우 곡선구간에서 구동이 불가능한 상태가 된다. 이러한 문제점을 개선하기 위하여 전동기의 역기전력 정보로부터 위상정보를 추출하여 곡선구간의 구동 제어알고리즘에 반영하였고, 제어시스템을 구성하여 곡선구간에서 전동기의 구동성능이 개선됨을 보인다.