• Proceedings of the Korean Information Science Society Conference
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• 2006.10b
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• pp.269-273
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• 2006

대화 에이전트의 역할은 사용자 입력으로부터 사용자의 의도를 분석하고 이에 따른 서비스를 제공하는 것이다. 하지만 사용자는 한 번에 서비스 제공에 필요한 모든 정보를 제공하지 않으므로 에이전트는 능동적으로 부가적인 정보를 추출할 수 있어야 한다. 따라서 자연스러운 대화를 진행하기 위해서 에이전트는 사용자주도형 대화와 시스템주도형 대화가 결합된 상호주도형 대화가 가능해야 한다. 본 논문에서는 상호주도형 대화를 제공할 수 있는 대화 에이전트의 스크립트(대화를 위한 데이터베이스) 언어를 제안한다. 제안한 방법은 대상 도메인에 맞춰서 대화 에이전트를 설계할 수 있도록, 도메인 관련 변수와 도메인 함수를 정의하여 사용할 수 있으며, 대화처리 기능으로, 사용자 의도 추론, 대화 흐름 관리, 사용자 입력 정보 추출 등의 기능을 지원한다. 제안한 방법의 가능성을 보이기 위해 일정관리 도메인에 제안하는 방법을 적용한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.5
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• pp.982-984
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• 2017

In time domain, a radar signal is divided into two segments: one is for a transmitted pulse and the other is for receiving possible returns from radar targets. Also the received signal is relatively weak and consists of background noise except for the reflected signals from radar targets. In this Letter, we present an energy detection based spectrum sensing for a radar signal in the presence of noise power uncertainty exploiting this characteristics.

• Proceedings of the KIEE Conference
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• 2002.04a
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• pp.190-197
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• 2002

The goal of this paper is to propose a virtual instrumentation system based on three dimensional current coordinates for monitoring power quality. A developed system with various experimental graphic screens and numerical results is made up 586-PC and DSP(digital signal processor) board, power quality analyzing and evaluating software for windows. Power parameters are analyzed using correlation signal processing techniques based on the correlation between voltage and current waveforms. Analysis results are visualized by 3-D current coordinates, and it is compared and evaluated with conventional time/frequency domain. To verify the validity of the proposed system, power and harmonic parameters of single phase induction motor drive system is analyzed and verified.

• Transactions of the Society of Information Storage Systems
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• v.1 no.1
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• pp.84-92
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• 2005

This work presents the feasibility of shunt damping far vibration suppression of the rotating HDD disk-spindle system using piezoelectric bimorph. A target vibration mode which significantly restricts the recording density increment of the drive is determined through modal analysis and a piezoelectric bimorph is designed to suppress unwanted vibration. After deriving the two-dimensional generalized electromechanical coupling coefficient of the shunted drive, the shunt damping of the system is predicted by simulating the displacement transmissibility using the coefficient. In addition, optimal design process using sensitivity analysis is undertaken in order to improve the shunt damping of the system. The effectiveness of the proposed methodology is verified through experimental implementation by observing the vibration characteristics of the rotating disk-spindle system in frequency domain.

• Journal of the Korean Society for Nondestructive Testing
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• v.32 no.3
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• pp.296-301
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• 2012

This paper describes an analytic method for infrared thermography to detect surface cracks in thin plates. Traditional thermographic method uses the spatial contrast of a thermal field, which is often corrupted by noise in the experiment induced mainly by emissivity variations of target surfaces. This study developed a robust analytic approach to crack detection for thermography using the holomorphic function of a temperature field in thin plate under steady-state thermal conditions. The holomorphic function of a simple temperature field was derived for 2-D heat flow in the plate from Cauchy-Riemann conditions, and applied to define a contour integral that varies depending on the existence and strength of singularity in the domain of integration. It was found that the contour integral at each point of thermal image reduced the noise and temperature variation due to heat conduction, so that it provided a clearer image of the singularity such as cracks.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.1 s.106
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• pp.3-11
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• 2006

This paper presents a new approach for hysteresis modeling of a magnetorheological (MR) fluid. The field-dependent hysteresis of MR fluid is investigated using the Preisach model. The commercial MR product (MRF-132LD, Lord Corporation) is employed. Its field-dependent shear stress is then obtained using a rheometer (MCR 300, Physica). In order to show the applicability of the Preisach model to the MR fluid, two significant properties; the minor loop property and the wiping-out. property are experimentally examined. Subsequently, the Preisach model for the MR fluid is identified using experimental first order descending (FOD) curves in discrete manner. The effectiveness of the identified hysteresis model is verified in the time domain by comparing the predicted field-dependent shear stress with the measured one. In addition, the hysteresis model proposed in this work is compared to Bingham model.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.4 no.6
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• pp.1194-1208
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• 2010

As visual surveillance systems gain wider usage in a variety of fields, it is important that they are capable of interpreting scenes automatically, also known as "human motion analysis" (HMA). However, existing HMA methods are too domain specific and computationally expensive. This paper proposes a general purpose HMA method that is based on the idea that human beings tend to exhibit erratic motion patterns during abnormal situations. Limb movements are characterized using the statistics of angular and linear displacements. In addition, the method is enhanced via the use of the entropy of the Fourier spectrum to measure the randomness of subject's motions. Various experiments have been conducted and the results indicate that the proposed method has very high classification accuracy in identifying anomalous behavior.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06c
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• pp.248-251
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• 2011

본 연구에서는, 웹 문서로부터 특정 상품에 대한 의견 문장을 분석하는 오피니언 마이닝(Opinion Mining) 연구의 일환으로, 특히 함께 공기하는 자질 명사에 따라 그 극성 값이 달라지는 '비결정 오피니언어휘'의 처리를 위해서 도메인을 '맛집'으로 한정하여 공기하는 도메인 키워드의 목록을 결정하고, 이를 부분문법그래프(Local Grammar Graphs) 방법론을 통해서 이들 간의 어휘 통사적 관계를 결정해 주었다.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.433-435
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• 2005

We have studied the realigning behavior of liquid crystal molecules in liquid crystalline polymer/liquid crystal(LCP/LC) system when they are exposed to external stimulation such as bending and pressing. The birefringence of the LCP/LC in a flexible display device was measured as a function of bending or pressing deformation. The microscopic dynamic behavior of main chain, side chain, and the LC were characterized by FTIR and polarization optical microscopy. When the device is deformed in scattering memory state, liquid crystal(LC) director is found to align from randomly oriented domain state(scattering state) to homeotropic state.

• Proceedings of the KIEE Conference
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• 2000.11c
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• pp.534-536
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• 2000

In this paper, propagation and damping characteristics of PD Pulse in GIS are analyzed using SNM. These characteristics are very important to make a diagnosis and protection of accident in GIS. SNM is numerical method in time domain and very useful method to analyze 3-Dimensional structure such as GIS. GIS modeling is made simply as the form of coaxial cable and then spacers are inserted in it. The scattering and reflection in the GIS are appeared and damping characteristics of PD pulse are shown. When simulation using SNM compare to measurement, two results are similar.