• 한국음향학회지
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• 제27권4호
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• pp.207-214
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• 2008

입체음향을 구현하는 방법으로는 다수의 스피커를 사용하는 다채널 음향재생 시스템과 2개의 스피커나 스테레오 헤드폰을 이용하는 2채널 음향재생 바이노럴 시스템이 있다. 그 중에서 공간 및 비용 상의 문제로 인하여 2채널을 이용한 음향재생시스템이 주목을 받고 있다. 일반적으로 2채널로 입체음향을 재생하기 위해서는 소리가 음원으로부터 청자의 두 귀에 이르는 경로를 모델링한 머리전달함수 (HRTF : Head Related Transfer Function)를 이용하지만 혼돈원추 상에서 음상정위의 혼돈을 주게 되므로 입체감을 저하시킨다는 단점이 있다. 본 논문에서는 2채널 입체음향 시스템을 효과적으로 구현하기 위하여 머리전달함수를 개선하는 알고리즘을 제안한다. HRTF 그룹화 및 심리음향을 이용하여 각 방향에 해당하는 주파수 스펙트럼 특성을 부각시키는 방법을 적용하였으며 시뮬레이션을 통하여 제안한 알고리즘이 정확한 방향감을 생성할 수 있음을 확인하였다.

• Nuclear Engineering and Technology
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• 제2권4호
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• pp.249-254
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• 1970

고 에너지 영역에서 비탄성핵을 가진 충격중성자 전도문제에서 시간과 에너지의 과도적인 특성은 연속 에너지 전도연산자로서 면밀히 해결했다. 점근적으로 가장 우세한 하나의 고정된 시간고유치를 발견했다. 완전한 해는 다음 세 부분으로 되어 있다. 1. 점근적으로 가장 우세한 시간과 에너지의 분리 가능형. 2. 과도적으로 감속하는 순 에너지에 의해서 결정된 분리 불가능형. 3. 점근적으로 무시할 수 있는 시간과 에너지의 혼합에 의하여 결정된 분리 불가능형.

• Journal of Electrical Engineering and Technology
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• 제12권5호
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• pp.1970-1979
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• 2017

Ultra Lift Luo Converter (ULC) gained considerable research interest in recent years. The stability analysis of voltage mode and peak current mode controlled ULC in continuous conduction mode is analyzed in this paper. The Eigen value theory is used for the stability analysis of voltage mode controlled ULC. Then to characterize the dynamics of inner current loop, the expressions of closed loop transfer function and loop gain are determined. An algorithm has been developed to analyze the stability of the peak current mode controlled ULC. The theoretical results are correlated with the simulation results obtained using PSIM 9.1(SMARTCTRL 1.0) software. Finally it is proposed to fabricate a prototype and validate the performance by suitable experimental setup.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 추계학술대회
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• pp.295-300
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• 2003

In discontinuous composite mechanics, shear lag theory is one of the most popular model because of its simplicity and accuracy. However, it does not provide sufficiently accurate strengthening predictions in elastic regime when the fiber aspect ratio is small. This is due to its neglect of stress transfer across the fiber ends and the stress concentrations that exist in the matrix regions near the fiber ends. To overcome this shortcoming, a more simplified shear lag model introducing the stress concentration factor which is a major function of modulus ratio is proposed. It is found that the proposed model gives a good agreement with finite element results and has the capability to correctly predict the values of intefacial shear stresses and local stress variations in the small fiber aspect ratio regime.

• The Journal of the Acoustical Society of Korea
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• 제16권3E호
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• pp.24-31
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• 1997

A mobile propagation characteristics for wideband DS-SS (Direct Sequence-Spectrum) signal is presented. Existing narrowband model is extended for the wideband pulse with an arbitrary shape. The received DS-SS signal in the frequency domain is the transfer function of the propagation channel weighted by the inverse Fourier transform. In this proposed method, received signal spectral density, instantaneous waveform, and Doppler spectrum of DS-SS signal via either Rayleigh of Rician channel can be obtained easily. Simulation results match well with both simulated theoretical fading statistics and classical theory. As expected, the extraction of chip timing in Rician fading shown to be more tractable than Rayleigh fading.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1999년도 제14차 학술회의논문집
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• pp.88-91
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• 1999

The purpose of this paper is to propose an approach to design a robust servo controller based on the Mixed H$_2$/H$\sub$$\infty$/ theory. In order to do this, we first modify the generalized plant for the usual H$\sub$$\infty$/ servo problem to a structure of the Mixed H$_2$/H$\sub$$\infty$/ minimization problem by virtue of the internal model principle. By doing this, we can divide specifications adopted for robust servo system design into H$_2$and H$\sub$$\infty$/ performance criteria, respectively. Then, the mixed H$_2$/H$\sub$$\infty$/ problem is solved in order to find the best solution, by which we can minimize H$_2$-norm of the transfer function under the condition of H$\sub$$\infty$/-norm value, through Linear Matrix Equality (LMI).

• Journal of Advanced Marine Engineering and Technology
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• 제28권5호
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• pp.762-772
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• 2004

Fatigue life of a Piston for large liquid Petroleum liquid injection(LPLi) bus engines is analyzed considering effects of cooling condition parameters : temperature of cooling water, and heat transfer coefficients at oil gallery and bottom surface of piston head. Temperature of the piston is analyzed with varying cooling conditions Stresses of the piston from two load cases of pressure loading. and pressure and thermal loading are analyzed Fatigue life under repeated peak pressure and thermal cycle is analyzed by the strain-life theory. For the two load cases, required loading cycles for engine life are defined, and loading cycles to failure and partial damages are calculated. Based on the resulting accumulated fatigue usage factors, endurance of the piston is evaluated and effects of varying cooling condition Parameters are discussed.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 춘계학술대회논문집 - 한국공작기계학회
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• pp.641-646
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• 2000

A milling process with 45 degree chamfered inserts produces a perfect flat surface only in theory. It is due to many unwanted factors including thermal effect, dynamic effect, the problem of the controller used and the problem of accuracy of the machine tool. In this study, introduced is a method to improve the surface roughness by redesigning of the chamfer angle of the insert, which traditionally has been 45 degree. First, the relationship between the fixed machine coordinate and the relative coordinate on the insert is derived. This transfer matrix is used to determine the new insert angle to maximize the flatness of the machined surface. A newly designed insert is manufactured, and used to carry out the experiment. It is proved that the insert designed by the proposed method produced a much flatter surface than a traditional one.

• 무역상무연구
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• 제29권
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• pp.143-172
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• 2006

This study focuses on the risk management of "Digital Goods" appeared with the progress of information technology(IT) in international transaction. As a result of that digital goods have a lot of uncertainty between the general goods or service which have been deal with object of international transaction broadly because digital goods hold uniqueness. In this study, the author give a definition of "Digital Goods" and make an examination of uniqueness of that in international transaction. Next, six risks are defined base on risk theory and risk analysis matrix applying risk mapping model is made. Conclusionally, risk transfer as insurance is adequate to manage business risk, security risk, credit risk and legal risk. Meanwhile, risk avoidance is adequate to manage reputation risk and market risk. But, this study have following three limits. Firstly, concerning definition of the risk, real case is not applied owing to lack of transaction data. Secondly, measuring of the risk is not based on absolute data but relative data. Lastly, suggesting way of risk management is not concrete and practical to international trader of digital goods.

• 건축역사연구
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• 제1권1호
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• pp.228-239
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• 1992

I'm going to endow with any characters to the mixed history of Korean Contemporary Architecture, and rearrange the relations between motive of transfer and the ideology which is concluded in expression through considering the transitional period which is based on the modernity, tradition and additional area such as ideology, politics, technology, literature, sculpture and painting etc. This abstract explain only characters of revivalism in Korean Contemporary Architecture. Revivalism have some complexed nationalistic leanings. Our transitional succession returned to revivalism that is limitted by its form. Of course, that is dued to complexed operating such as the Ideal Nationalism against the severance of our culture which had been done by Japan, the Superior Nationalism which is developed by antagonism of our own ideology was dued to dividing into sections of our own country, and the Resistant Nationalism against foreign culture.