• 한국정보통신학회논문지
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• 제17권8호
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• pp.1777-1783
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• 2013

시간영역 해석 기법의 하나인 전달선로행렬 모델링을 이용하여 수중물체 이동시 나타나는 도플러 효과를 구현하는 방법에 관한 연구를 수행하였다. 수중물체가 이동하는 상황을 고려하기 위해 입력 신호의 위치를 수중물체의 이동속도에 맞추어 매 시각 마다 신호를 입력한 결과, 최대 2.47%의 아주 작은 오차 범위에서 도플러 효과를 얻을 수 있었다. 또한, 수중물체의 이동 속도를 조절하기 위해 입력 신호의 입력 속도를 조절하는 것에 의해 이론치와 비교하여 최대 0.63% 이내의 오차를 가지는 신뢰할 수 있는 수치 시뮬레이션 결과를 얻을 수 있었다.

• Journal of the Optical Society of Korea
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• 제18권4호
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• pp.317-329
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• 2014

In vision measurement systems based on structured light, the key point of detection precision is to determine accurately the central position of the projected laser line in the image. The purpose of this research is to extract laser line centers based on a decision function generated to distinguish the real centers from candidate points with a high recognition rate. First, preprocessing of an image adopting a difference image method is conducted to realize image segmentation of the laser line. Second, the feature points in an integral pixel level are selected as the initiating light line centers by the eigenvalues of the Hessian matrix. Third, according to the light intensity distribution of a laser line obeying a Gaussian distribution in transverse section and a constant distribution in longitudinal section, a normalized model of Hessian matrix eigenvalues for the candidate centers of the laser line is presented to balance reasonably the two eigenvalues that indicate the variation tendencies of the second-order partial derivatives of the Gaussian function and constant function, respectively. The proposed model integrates a Gaussian recognition function and a sinusoidal recognition function. The Gaussian recognition function estimates the characteristic that one eigenvalue approaches zero, and enhances the sensitivity of the decision function to that characteristic, which corresponds to the longitudinal direction of the laser line. The sinusoidal recognition function evaluates the feature that the other eigenvalue is negative with a large absolute value, making the decision function more sensitive to that feature, which is related to the transverse direction of the laser line. In the proposed model the decision function is weighted for higher values to the real centers synthetically, considering the properties in the longitudinal and transverse directions of the laser line. Moreover, this method provides a decision value from 0 to 1 for arbitrary candidate centers, which yields a normalized measure for different laser lines in different images. The normalized results of pixels close to 1 are determined to be the real centers by progressive scanning of the image columns. Finally, the zero point of a second-order Taylor expansion in the eigenvector's direction is employed to refine further the extraction results of the central points at the subpixel level. The experimental results show that the method based on this normalization model accurately extracts the coordinates of laser line centers and obtains a higher recognition rate in two group experiments.

• Journal of Electrical Engineering and Technology
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• 제13권6호
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• pp.2521-2529
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• 2018

This paper deals with a sampled-data tracking control problem for the Takagi-Sugeno fuzzy system with external disturbances. We derive a stability condition guaranteeing both asymptotic stability and H-infinity tracking performance by employing a newly proposed time-dependent line-integral fuzzy Lyapunov-Krasovskii functional. A new integral inequality is also introduced, by which the proposed stability condition is formulated in terms of linear matrix inequalities. Finally, the effectiveness of the proposed method is demonstrated through a simulation example.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2002년도 생물공학의 동향 (X)
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• pp.53-56
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• 2002

Mammalian cell based biosensor kits are expected to be in assessment of samples toxicity more sensitive and accurate. A recombinant fluorescent Chinese Hamster Ovary (CHO) cell line was known to be responsive to the various toxicants Specially. KFC- AlO cell line. which contain the c-fos SRE::GFP plasmid (pKFG). was found to be able to detect toxicants sensitively. A biosensor kit was developed by using an immobilized KFC-A10 cell line. Immobilized recombinant fluorescent cells within agarose, known as a representative hydrogel matrix, have been maintained in the matrix viably and have shown constant fluorescent levels for long time. Immobilized cells have shown the ability to detect the chemical toxicity in the keep of fluorescent level as the metabolism is inhibited under toxic conditions.

• 동력기계공학회지
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• 제3권1호
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• pp.74-79
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• 1999

This paper describes formulation for algorithm of time historical response analysis of vibration for straight-line structure. This method is derived from a combination of the transfer stiffness coefficient method and the Newmark method. And this present method improves the computational accuracy of the transient vibration response analysis remarkably owing to several advantages of the transfer stiffness coefficient method. We regarded the structure as a lumped mass system here. The analysis algorithm for the time historical response was formulated for the straight-line structure containing crooked, tree type system. The validity of the present method compared with the transfer matrix method and the Finite Element Method for transient vibration analysis is demonstrated through the numerical computations.

• KIEE International Transactions on Power Engineering
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• 제3A권2호
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• pp.79-84
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• 2003

Unbalanced systems, such as distribution systems, have difficulties in fault locations due to single-phase laterals and loads. This paper proposes new fault locations developed by the direct three-phase circuit analysis algorithms using matrix inverse lemma for the line-to-ground fault case and the line-to-line fault case in unbalanced systems. The fault location for balanced systems has been studied using the current distribution factor, by a conventional symmetrical transformation, but that for unbalanced systems has not been investigated due to their high complexity. The proposed algorithms overcome the limit of the conventional algorithm using the conventional symmetrical transformation, which requires the balanced system and are applicable to any power system but are particularly useful for unbalanced distribution systems. Their effectiveness has been proven through many EMTP simulations.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집 특별세미나,특별/일반세션
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• pp.403-406
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• 2009

Recently, electricity is essential for human lives. Modem people take cultural benefits due to the development of the electric power system and the spread of the high tech-electric appliances, the cell phones, and etc. However, the electromagnetic field problems become prominent figures owing to the fault of the communication devices around the power line and the biological effect, and etc. In this paper, we introduce the simple electromagnetic field calculation based on the transmission line matrix method, prior to the analysis about the influence of electromagnetic field. Simulation object is the inner part of the trailer car in the high speed train. Unlike the existing paper we submitted, we analyze not only the magnetic field but the electric field in the inner part of the trailer car which makes up the high speed train.

• 한국정보통신학회논문지
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• 제15권7호
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• pp.1479-1486
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• 2011

본 논문에서는 후판 영상에서 직선 패턴을 검출하는 간단하면서도 정확한 알고리즘을 제안한다. 후판의 직선 검출은 후판 영상으로부터 후판에 관련된 정보를 분석하거나 인식할 때 기본적으로 사용되는 핵심적인 알고리즘이다. 제안하는 알고리즘에서는 마스크를 이용하여 전체 영상을 탐색하면서 에지 영상을 분석한다. 먼저 마스크에 위치한 에지 패턴의 픽셀들에 대한 공분산 행렬을 계산하고 공분산 행렬의 고유값과 에지 패턴의 통계적 기하학적인 특성 사이의 관계를 분석하여 직선 에지를 검출한다. 직선 패턴이 중복된 에지 영상에 대해서는 모든 직선을 정확하게 검출하기 위하여 먼저 각 직선 패턴을 전체 영상에서 분리한 후 고유값을 계산한다. 또한 에지를 구성하는 픽셀의 수와 에지의 방향 정보를 이용하여 불필요한 직선 에지들을 제거함으로써 후판의 직선 에지를 정확하게 검출하도록 한다. 다양한 후판 영상에 대해서 실험을 수행한 결과는 제안하는 알고리즘이 고유값을 이용한 기존 알고리즘 보다 우수함을 보여준다.

• Journal of Astronomy and Space Sciences
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• 제29권3호
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• pp.287-293
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• 2012

Satellite operating agencies are constantly monitoring conjunctions between satellites and space objects. Two line element (TLE) data, published by the Joint Space Operations Center of the United States Strategic Command, are available as raw data for a preliminary analysis of initial conjunction with a space object without any orbital information. However, there exist several sorts of uncertainties in the TLE data. In this paper, we suggest and analyze a method for estimating the uncertainties in the TLE data through mean, standard deviation of state vector residuals and covariance matrix. Also the estimation results are compared with actual results of orbit determination to validate the estimation method. Characteristics of the state vector residuals depending on the orbital elements are examined by applying the analysis to several satellites in various orbits. Main source of difference between the covariance matrices are also analyzed by comparing the matrices. Particularly, for the Korea Multi-Purpose Satellite-2, we examine the characteristics of the residual variation of state vector and covariance matrix depending on the orbital elements. It is confirmed that a realistic consideration on the space situation of space objects is possible using information from the analysis of mean, standard deviation of the state vector residuals of TLE and covariance matrix.

• Journal of Power Electronics
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• 제17권3호
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• pp.641-652
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• 2017

This paper proposes a cost-effective topology to drive a three-phase open-end load based on a five-leg indirect matrix converter (IMC) and a space vector modulation (SVM) method. By sharing an inverter leg with two load terminals, the proposed topology can reduce the number of power switches when compared to topologies based on a direct matrix converter or a six-leg IMC. The new SVM method uses only the active vectors that do not produce common-mode voltage (CMV), which results in zero CMV across the load phase and significantly reduces the peak value of the CMV at the load terminal. Furthermore, the proposed drive system can increase the voltage transfer ratio up to 1.5 and provide a superior performance in terms of an output line-to-line voltage with a three-level pulse-width modulation waveform. Simulation and experimental results are given to verify the effectiveness of the proposed topology and the new SVM method.