• 말소리와 음성과학
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• 제6권4호
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• pp.133-139
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• 2014

This paper describes several approaches to transform a speaker's individuality to another's individuality using frequency warping between bilingual formant frequencies on different language environments. The proposed methods are simple and intuitive voice conversion algorithms that do not use training data between different languages. The approaches find the warping function from source speaker's frequency to target speaker's frequency on formant space. The formant space comprises four representative monophthongs for each language. The warping functions can be represented by piecewise linear equations, inverse matrix. The used features are pure frequency components including magnitudes, phases, and line spectral frequencies (LSF). The experiments show that the LSF-based voice conversion methods give better performance than other methods.

• Journal of the Korean Data and Information Science Society
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• 제16권4호
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• pp.943-949
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• 2005

An economic design of specification limits for production process of ham is considered for a given process mean in a complete inspection plan. Each ham is inspected, and if it meets the specification, it is accepted. The ham less than the lower specification limit are changed another products or at a discounted price, and those greater than the upper specification limit are reworked. A profit model is developed which involves selling price, production cost, rework cost and the cost which is incurred by imperfect quality. Methods for finding the optimal specification limits are derived for the case of piecewise linear loss function with an industrial case study.

• 한국전자파학회논문지
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• 제11권3호
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• pp.358-364
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• 2000

In this paper, an efficient moment-method technique is proposed for analyzing rectangular waveguide E-plane filters. Techniques are presented for the fast evaluation of Green's function and for the efficient evaluation of integrals arising in the E-plane of the rectangular waveguide. The structure boundary is represented by the piecewise linear segments. Simple pulse-expansion and point-matching technique are used. The entire E-plane filter structure is simulated by the method of moments. Three representative cases of the E-plane filter are analyzed and compared with results by other researchers.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2010년 춘계학술발표회 논문집
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• pp.221-224
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• 2010

When the image registration methods which were generally used to the low medium resolution satellite images is applied to the high spatial resolution images, some matching errors or limitations might be occurred because of the local distortions in the images. This paper, therefore, proposed the automatic image-to-image registration of high resolution satellite images using local properties of control points to improve the registration result.

• 경영과학
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• 제10권1호
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• pp.193-205
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• 1993

This paper presents a mathematical model for a class of vertical integration decisions. The problem structure of interest consists of raw material vendors, components suppliers, components processing plants, final product (assembly) plants and external components buyers. Economic feasibility of operating components plants instead of keeping outside suppliers is our major concern. The model also determines assignment of product lines and production volumes to each open plant considering the cost impacts of economies of scale and plant complexity. The problem formulation leads to a concave, mixed integer mathematical program. Given the state of the art of nonlinear programming techniques, it is often not possible to find global optima for reasonably sized such problems. We developed an optimization solution algorithm within the framework of Benders decomposition for the case of a piecewise linear concave cost function. It is shown that our algorithm generates optimal solutions efficiently.

• 한국군사과학기술학회지
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• 제13권3호
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• pp.461-469
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• 2010

In this paper, we have proposed an improved fusion method of detection features which can enhance the detection probability under the given false alarm rate in the prescreening stage of SAR ATR(Synthetic Aperture Radar Automatic Target Recognition) system. Since the detection features have the positive correlation, the detection performance can be improved if the joint probability distribution of detection features is considered in the fusion process. The detection region is designed as a simple piecewise linear function which can be represented by few parameters. The parameters for the detection region can be derived by training the sample SAR images to maximize the detection probability with the given false alarm rate. Simulation result shows that the detection performance of the proposed method is improved for all combinations of detection features.

• 조명전기설비학회논문지
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• 제16권5호
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• pp.75-82
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• 2002

본 논문에서는 열병합발전설비의 최적운용계획을 위한 새로운 수리적 모델을 제안하였다. 본 논문에서 제안한 알고리즘은 에너지생산량에 따른 비용의 비선형적인 문제를 구간별로 선형화된 함수를 이용하여 혼합정수 계획법으로 모델링하였다. 제안한 수리적 모델은 종래 제시되었던 열병합발전설비의 최적운용을 위한 모델링 기법에서 해결하지 못했던 한계사항을 극복한 것으로서, 더욱 현실에 근접한 최적운용을 위한 모델이 되었다. 또한 본 연구에서는 시뮬레이션을 통해 다양한 사례에 대한 열병합발전설비의 최적 운용계획을 제시함으로서 수리적 모델의 유용성을 입증하였다.

• 한국측량학회지
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• 제29권6호
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• pp.667-675
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• 2011

본 논문은 이종센서자료인 고해상도 KOMPSAT-2 영상과 TerraSAR-X 영상 간 자동기하보정을 수행하는 것을 목적으로 한다. 이를 위해, 두 영상간의 x, y 방향의 초기 변위량을 MI(Mutual Information) 기법을 통해 계산한 후, 계산된 위치만큼 TerraSAR-X 영상을 이동시켜서 두 영상 간 초기 위치 차이를 최소화하였다. 초기 위치 차이가 최소화된 두 영상에서 선형정보를 추출하여 이들 간의 유사도를 판단, 매칭쌍을 추출하고자 하였다. 특히, 영상 전반에 걸쳐 고르게 분포된 매칭쌍을 추출하기 위하여, 영상 전역에 걸쳐서 동일한 크기의 격자망을 구성하여, 각 격자망에서 하나의 매칭쌍만을 추출하도록 하였다. 이렇게 추출된 매칭쌍을 이용하여 선형(rigid)과 비선형(nonrigid)의 변환식이 결합된 모델을 통해 기하보정 정확도를 높이고자 하였고, 실험 결과 모든 대상지역에서 5m 이내의 RMSE 값을 도출하였다.

• 전기전자학회논문지
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• 제5권1호
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• pp.1-7
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• 2001

본 논문에서 역 방향 링크 채널에 대해 비 선형 등화기를 이용하여 CDMA 셀룰라 시스템을 연구하였다. 일반적으로 무선 통신에서 불확실한 채널 특성 때문에 Observable 들의 확률분포는 유한 세트의 파라미터로 규정될 수 없다. 대신에 training 샘플에 기반을 둔 Quantile과 Vector Quantizer를 사용함으로서 유한 수의 disjoint된 영역으로 m차 샘플 공간으로 분할하였다. 제안된 알고리듬은 RMSA 알고리즘에 의해 예측된 Quantile와 조건부 분할 모멘트에 따른 regression function의 부분적인 근사에 근간을 두고 있다. 본 논문의 등화기와 검출기는 잡음 분포의 Variation에 민감하지 않다는 관점에서 상당히 강한 특성을 보여 준다. 주요 아이디어는 Robust equalizer와 Robust partition detector가 어떤 환경의 무선 채널 하에서도 partition되지 않은 Observation space의 일반적인 등화기 보다 Observation의 등 확률로 분할된 부 공간에서 더 낳은 성능을 보여 준다. 또한 이런 개념을 CDMA 시스템에 적용하여 BER 성능을 분석하였다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2002년도 봄 학술발표회 논문집
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• pp.123-130
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• 2002

A general formulation for shape design sensitivity analysis over three dimensional beam structure is developed based on a variational formulation of the beam in linear elasticity. Sensitivity formula is derived based on variational equations in cartesian coordinates using the material derivative concept and adjoint variable method for the displacement and Von-Mises stress functionals. Shape variation is considered for the beam shape in general 3-dimensional direction as well as for the orientation angle of the beam cross section. In the sensitivity expression, the end points evaluation at each beam segment is added to the integral formula, which are summed over the entire structure. The sensitivity formula can be evaluated with generality and ease even by employing piecewise linear design velocity field despite the bending model is fourth order differential equation. For the numerical implementation, commercial software ANSYS is used as analysis tool for the primal and adjoint analysis. Once the design variable set is defined using ANSYS language, shape and orientation variation vector at each node is generated by making finite difference to the shape with respect to each design parameter, and is used for the computation of sensitivity formula. Several numerical examples are taken to show the advantage of the method, in which the accuracy of the sensitivity is evaluated. The results are found excellent even by employing a simple linear function for the design velocity evaluation. Shape optimization is carried out for the geometric design of an archgrid and tilted bridge, which is to minimize maximum stress over the structure while maintaining constant weight. In conclusion, the proposed formulation is a useful and easy tool in finding optimum shape in a variety of the spatial frame structures.