• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1988년도 한국자동제어학술회의논문집(국내학술편); 한국전력공사연수원, 서울; 21-22 Oct. 1988
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• pp.210-213
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• 1988

By using Lyapunov method, sufficient conditions for linear time-varying continuous-time and discrete-time systems to be stable are presented under the assumption that the systems are slowly time-varying. Though it is not simple to find the stability regions immediately, one could find practical and large stability regions by constructing an appropriate algorithm.

• 대한수학회보
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• 제53권5호
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• pp.1281-1289
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• 2016

Richard Stanley suggested the problem of finding combinatorial proofs of formulas for counting regions of certain hyperplane arrangements defined by hyperplanes of the form $x_i=0$, $x_i=x_j$, and $x_i=2x_j$ that were found using the finite field method. We give such proofs, using embroidered permutations and linear extensions of posets.

• 대한전기학회논문지:시스템및제어부문D
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• 제49권4호
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• pp.183-190
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• 2000

It is well-known that the poles of a system are closely related with the dynamics of the systems, and the pole assignment problem, which locates the poles in the desired regions, in one of the major problem in control theory. Also, it is always possible to assign poles to specific points for exactly known linear systems. But, it is impossible for the uncertain linear systems because of the uncertainties that originate from modeling error, system variations, sensing error and disturbances, so we must consider some regions instead of points. In this paper, we consider both the analysis and the design of robust pole assignment problem of linear system with time-varying uncertainty. The considered uncertainties are the unstructured uncertainty and the structured uncertainty, and the considered region is the circular region. Based on Lyapunov stability theorem and linear matrix inequality(LMI), we first present the analysis result for robust pole assignment, and then we present the design result for robust pole assignment. Finally, we give some numerical examples to show the applicability and usefulness of our presented results.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 신호처리소사이어티 추계학술대회 논문집
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• pp.229-232
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• 2003

In this paper, we present an efficient algorithm to detect microcalcifications ROI (Regions of Interest) in digital mammograms using Linear filters. To efficiently detect microcalcifications ROI, we used three sequential processes; preprocessing for breast area detection, modified multilevel thresholding, ROI selection using mean filter and linear filters.

• Earthquakes and Structures
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• 제25권6호
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• pp.429-442
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• 2023

To study the seismic vulnerability of the composite material structure of adobe and timber, we collected and statistically analysed empirical observation samples of 542,214,937 m² and 467,177 buildings that were significantly impacted during the 179 earthquakes that occurred in mainland China from 1976 to 2010. In multi-intensity regions, combined with numerical analysis and a probability model, a non-linear continuous regression model of the vulnerability, considering the empirical seismic damage area (number of buildings) and the ratio of seismic damage, was established. Moreover, a probability matrix model of the empirical seismic damage mean value was provided. Considering the coupling effect of the annual and seismic fortification factors, an empirical seismic vulnerability curve model was constructed in the multiple-intensity regions. A probability matrix model of the mean vulnerability index (MVI) was proposed, and was validated through the above-mentioned reconnaissance sample data. A matrix model of the MVI of the regions (19 provinces in mainland China) based on the parameter (MVI) was established.

• 한국멀티미디어학회논문지
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• 제14권11호
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• pp.1365-1372
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• 2011

본 논문은 어두운 영상의 낮은 인지적인 대비를 향상하기 위해 비선형 마스킹 기법을 이용한 영상의 인지적 대비 향상 방법을 제안한다. 영상의 주요 속성인 색도의 변화를 최소화 하면서 어두운 영역의 밝기를 향상시키기 위해, 비선형 마스킹 기법 기반으로 영상에 적응적인 파라미터를 이용한 대비 향상방법을 제안하 였다. 제안하는 방법의 성능을 평가하기 위해 테스트 영상에 대해 SSR(Single-Scale Retinex), MSR(Multi-Scale Retinex), 기존의 비선형 마스킹 기법의 결과와 색도 및 채도에 대한 정량적인 평가와, z-score를 이용한 정성적 평가를 수행하였다. 결과 제안한 방법이 낮은 색도 변화와 향상된 인지적 대비를 보임을 확인하였다.

• Structural Engineering and Mechanics
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• 제12권1호
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• pp.35-50
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• 2001

A numerical methodology is presented in this paper for the geometrically non-linear analysis of slender uni-dimensional structural elements under unilateral contact constraints. The finite element method together with an updated Lagrangian formulation is used to study the structural system. The unilateral constraints are imposed by tensionless supports or foundations. At each load step, in order to obtain the contact regions, the equilibrium equations are linearized and the contact problem is treated directly as a minimisation problem with inequality constraints, resulting in a linear complementarity problem (LCP). After the resulting LCP is solved by Lemke's pivoting algorithm, the contact regions are identified and the Newton-Raphson method is used together with path following methods to obtain the new contact forces and equilibrium configurations. The proposed methodology is illustrated by two examples and the results are compared with numerical and experimental results found in literature.

• 전자공학회논문지A
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• 제33A권6호
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• pp.158-163
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• 1996

In the conventional GaAs MESFET circuit simulation, the DC and transient simulation results are often failed due to the discontrinuities of the first and second order derivatives arising from the use of separate C-V models in linear, satruration, and transition regions. In this paper, we propose a unified capacitance model for linear, transition, and saturation regions by using a unified channel length modulation effect that is derived by extending the channel length modulation effect in the saturation region to the linear region. Calculated resutls from the proposed capacitance model agree well with 2-D device simulation resutls. Thus, the proposed model is expected to be useful in circuit simulation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 정기총회 및 창립40주년기념 학술대회 학회본부
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• pp.334-337
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• 1987

An algorithm is presented which computes the perimeter of regions in images represented by BF( breadth first) linear quadtree. In order to compute the perimeter, we determine adjacent neighbor nodes in the horizontal and vertical directions. It is the method which directly find the associated nodes in order to know whether it exists in BF linear quad tree or not. Average execution time of the algorithm is proportional to the number of black nodes in the quadtree.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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• pp.907-912
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• 1989

A new procedure is presented for optimally placing closed-loop poles of multivariable continuous-time systems in specified regions via linear-quadratic(LQ) state-feedback design. This method has the advantages of pole-placement and LQ-design. In addition, it provides minimum feedback gains in the control law.