• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.12
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• pp.1745-1747
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• 2016

In this paper, we propose a construction method of irregular quasi-cyclic low-density parity-check codes based on perfect difference families with various block sizes. The proposed codes have advantages in that they support various values with respect to code rate, length, and degree distribution. Also, this construction enables very short lengths which are usually difficult to be achieved by a random construction. We verify via simulations the error-correcting performance of the proposed codes.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.3
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• pp.40-45
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• 2008

This paper proposes the signal design techniques of quasi-orthogonal space time block codes (QO-STBCS) on the multi-dimensional signal space. In the multiple antenna system(MIMO), QO-STBC achieves the full-diversity and full-rate by grouping two based-symbols. We study the condition for the full-diversity of the grouping QO-STBC geometrically and the performance analysis of codes on the multi-dimensional signal space regarding the various signal constellations. Simulation results show that the way of the performance analysis is validity.

• Proceedings of the KIPE Conference
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• 2010.11a
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• pp.3-4
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• 2010

본 논문에서는, PWM 컨버터의 교류 전원 인터페이스를 위한 LCL 필터 설계에 대해 기술한다. 새로운 형태의 LCL 필터 전류 제어기를 소개하고 기존의 전류 제어 방식을 통한 필터 설계 값에 제안된 제어 기법을 적용 시켜 전류 제어 결과를 분석한 후, 제안된 제어기를 통한 필터 설계 측면에서의 유연성 및 용이함에 대해 언급한다. 분석의 타당성을 입증하기 위해 모의 실험 결과를 첨부하였다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.1
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• pp.105-114
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• 2004

In this paper, we design the circuits for DC parameter test of semiconductor devices. The DC parameter tester is the system which inspects the DC parameters of semiconductor devices. In the designed circuits, voltage(current) forcing current(voltage) sensing methods are used to inspect the parameters. The designed circuits are simulated by OR-CAD. The simulation results have good performance.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.463-463
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• 2016

최근 도시물순환 복원 및 치 이수효과 증대를 위해 저영향개발기법(Low Impact Development) 연구가 활발하게 진행 중이다. 하지만 대부분이 수치모델을 활용한 설계프로그램 개발에 대한 연구에 집중되어 있는 실정이며, 이러한 프로그램을 활용한 설계 시 최적의 매개변수 결정에 한계가 있다. 이러한 이유로 본 연구에서는 건축형 LID 요소 중 하나인 식생여과장치(Planter Box)의 모형실험을 통해 프로그램 모의에 필요한 매개변수를 추정하고, 모의를 수행한 후 모형실험 결과와 프로그램 모의 결과를 비교하여 최종적으로 식생여과장치의 설계 매개변수를 산정하고자 한다. 식생여과장치의 모형실험을 위하여 가로 1.5m, 세로 1.5m, 높이 1.5m로 실험 장치를 제작하였으며, 강우-유출수 실험 전 시료의 침투율, 함수비 등을 체크한 후 지속시간 1시간의 재현빈도 5년, 10년, 20년, 50년에 해당하는 강우강도에 대해 실험을 수행하였다. 실험결과로 나타난 자료는 SWMM 모형과 비교분석해 모형에 적용된 매개변수의 적합성을 분석하였으며, 재현빈도 5년, 10년, 20년의 경우 $R^2$ 값이 0.88~0.97로 실험 값과 모의 값의 연관성이 높게 나타났으며, 재현 빈도 50년의 경우 0.7835로 비교적 연관성이 낮게 나타났다.

• Journal of Convergence for Information Technology
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• v.10 no.7
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• pp.138-146
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• 2020

The paper deals with comparative study of characteristics of surrogate models and sensitivity evaluation using design of experiments in order to enhance and analysis the structure design of an automatic salt collector under various design load conditions. Orthogonal array design based on numerical analysis was used for the design of experiments. The thickness sizing variables of main structure member were considered the design factors, and the output responses were selected from the strength performances as well as the weight. The quantitative effects on responses for each design factor were evaluated from the orthogonal array experiment. Optimum design case was also identified to improve the strength performances with weight minimization. Using the orthogonal array experiment. various surrogate models such as response surface model, Kriging model, and Chebyshev orthogonal polynomial were generated. The orthogonal array experiment results were validated by the surrogate modeling results. The most suitable surrogate model was the response surface model for the exploration of design space of the automatic salt collector.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.1245-1248
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• 2012

반도체와 LCD 산업분야, 나노급 공정 및 검사기술이 요구되는 산업분야의 수요증가에 따라 초정밀 가공/생산/검사 장비를 설치, 운용하는 FAB. 구조물의 설계요구가 증대되고 있으며, 건물의 환경진동 규제치도 강화되고 있는 실정이다. 이와 같은 대형 구조물에서의 서브 마이크로 수준의 미진동(微振動)을 제어하는 문제는 진동 응답을 결정하는 구조와 재료가 복잡하고 다양한 형태를 갖고 있는 반면, 다루어야 할 동적 응답은 극한적으로 작은 마이크로 이하의 값을 다루어야 하기 때문에 매우 어렵다. 따라서 기존에 이용되고 있는 해석과 실험의 결과만으로는 신모델 설계에 적용하기 어렵다. 따라서, 본 논문에서는 실험적 데이터와 경험적 데이터들을 기반으로 구축된 데이터베이스를 이용하여 새로운 초정밀 FAB. 동적 구조 설계 시스템을 구현한다.

• Journal of the Earthquake Engineering Society of Korea
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• v.6 no.5
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• pp.53-58
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• 2002

A recent development, a concrete-filled steel(CFS) pier is an alternative to a reinforced concrete bridge pier in an urban area, because of its fast construction and excellent ductility against earthquakes. The capacity of CFS piers has not been used to a practical design, because there is no guide of a seismic design for CFS piers. Therefore, the guide of a seismic design value is derived from tests of CFS piers in order to apply it to a practical seismic design. Steel piers and concrete-filled steel piers are tested with constant axial load using quasi-static cyclic lateral load to check ductile capacity and using the real Kobe ground motion of pseudo-dynamic test to verify seismic performance. The results prove that CFS piers have more satisfactory ductility and strength than steel piers and relatively large hysteretic damping in dynamic behaviors. The seismic performance of steel and CFS piers is quantified on the basis of the test results. These results are evaluated through comparison of both the response modification factor method by elastic response spectrum and the performance-based design method by capacity spectrum and demand spectrum using effective viscous damping. The response modification factor of CFS piers is presented to apply in seismic design on a basis of this evaluation for a seismic performance.

• Journal of the Korea Concrete Institute
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• v.16 no.5 s.83
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• pp.697-707
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• 2004

Most bridge piers were practically designed and constructed with lap spliced longitudinal reinforcing steels before the 1992 seismic design provisions of Korea Bridge Design Specification were implemented. It has been known that lap splice of longitudinal reinforcement in the plastic hinge region is not desirable for seismic performance of RC bridge piers. The objective of this research is to evaluate the seismic performance of existing circular reinforced concrete bridge piers by the Quasi-static test and to propose the need of seismic retrofit of existing bridge piers through the damage level. Test specimens were nonseismically designed with the aspect ratio 4.0 which could induce the flexural failure mode. It was confirmed from this experiment that significant reduction of seismic performance was observed for test specimens with lap spliced longitudinal reinforcing steels. Pertinent seismic retrofit was determined to be needed for existing RC bridge piers with the lap-spliced of $50\%$ longitudinal reinforcing steels.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.6
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• pp.491-494
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• 2016

A design method is proposed to minimize the scattering cross section(SCS) of the electromagnetic cloak based on the quasi-conformal mapping. Often times in such cloaking structures, parts that require refractive index below one are approximated with free space because of the difficulty involved with realization. In this process, preformance degradation is inevitable. In this work, the size of the cloak is optimized to compensate for the deterioration, and thus to minimize the scattering cross section of a diamond shaped conductor. Proposed cloak is fabricated using a 3D printer, and verified by measuring the cloaking performance of a diamond shaped aluminum target.