• 한국구조물진단유지관리공학회 논문집
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• 제23권5호
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• pp.96-103
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• 2019

중층 철근콘크리트 주거형 건물은 국내에서 많은 비중을 차하며, 이러한 건물의 시공단계에서 발생 될 수 있는 문제에 대한 구조성능 분석이 필요하다. 이를 위하여, 25층 규모의 중층 철근콘크리트 주거형 건물을 예제모델로 선정해 구조성능 분석을 진행하였다. 예제모델을 5층, 10층, 15층, 20층, 25층의 시공단계 모델과 설계가 완료된 완공단계 모델로 구분해 구조해석을 수행하였다. 완공단계와 시공단계 모델들에 대하여, 고유치해석, 횡력저항성능, 완공단계에서의 설계강도비와 시공단계에서의 설계강도비를 비교를 통한 단면성능 검토를 수행하였다. 검토 결과, 시공단계와 완공단계 모두 횡변위와 층간변위비에서 건축구조기준 제한을 초과하지 않았는 것을 확인하였고, 단면성능 검토에서는 벽체의 일부 데이터를 제외한 모든 부재에서 구조적 안전성을 확인하였다. 따라서, 중층 철근콘크리트 주거형 건물의 완공단계에서 구조적 안정성이 확보되면 시공단계에서도 구조적 안정성 학보가 이루어진다는 결론을 도출할 수 있었다.

• Journal of the Korean Data and Information Science Society
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• 제27권2호
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• pp.539-548
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• 2016

This paper is a study on the multivariate CUSUM control charts using three different control statistics for monitoring covariance matrix. We get control limits and ARLs of the proposed multivariate CUSUM control charts using three different control statistics by using computer simulations. The performances of these proposed multivariate CUSUM control charts have been investigated by comparing ARLs. The purpose of control charts is to detect assignable causes of variation so that these causes can be found and eliminated from process, variability will be reduced and the process will be improved. We show that the charts based on three different control statistics are very effective in detecting shifts, especially shifts in covariances when the variables are highly correlated. When variables are highly correlated, our overall recommendation is to use the multivariate CUSUM control charts using trace for detecting changes in covariance matrix.

• 한국경영과학회지
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• 제25권3호
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• pp.17-33
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• 2000

We consider the Steiner tree packing problem. For a given undirected graph G =(V, E) with positive integer capacities and non-negative weights on its edges, and a list of node sets(nets), the problem is to find a connection of nets which satisfies the edge capacity limits and minimizes the total weights. We focus on the switchbox routing problem in knock-knee model and formulate this problem as an integer programming using Steiner tree variables. The model contains exponential number of variables, but the problem can be solved using a polynomial time column generation procedure. We test the algorithm on some standard test instances and compare the performances with the results using cutting plane approach. Computational results show that our algorithm is competitive to the cutting plane algorithm presented by Grotschel et al. and can be used to solve practically sized problems.

• 한국시뮬레이션학회논문지
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• 제4권1호
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• pp.59-73
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• 1995

Local area networks(LANs) recently become so large that they exceed their architected limits and users on different LANs may need to talk each other. This trend has led to a growth in the practice of interconnecting many heterogeneous LANs. In this paper, we proposed a method to interconnect Ethernets and token rings, which are widely used today, through a fast FDDI network. We also developed a simulation tool to evaluate the performances of the interconnected networks. We used a simulation language SLAM II for modeling and OSF/MOTIF X-window for user interface. The developed tool can be used to make a decision which interconnecting method is suitable for a given environment before interconnecting many heterogeneous LANs.

• 대한기계학회논문집
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• 제9권2호
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• pp.190-201
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• 1985

본 논문에서는 측정된 공작기계의 동적성능은 절삭조건과 공작기계의 동적 컴 플라이언스의 복합적인 함수이므로 공작기계의 동적 성능을 정확히 평가하고 설계.개 선을 용이하게 하기 위하여는 직접절삭시험 중 가진 시험을 동시에 수행하는 방법이 필요하다. 본 연구에서는 선반의 외경 선삭가공중의 동적성능을 직접절삭시험과 가 진 직접절삭법을 통하여 평가하고자 한다.

• 대한화학회지
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• 제35권6호
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• pp.699-706
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• 1991

헬륨 기체를 사용하여 중급 출력(500W) 마이크로파 유도 플라즈마(Microwave Induced Plasma:MIP)를 헬륨 기체를 사용하여 만든 뒤 직접 수용액 시료 분석에 사용하였다. Beenakker의 cavity를 변형시켜 얻은 안정된 헬륨 플라즈마는 실린더 형태의 모양을 하고 있고 기체의 흐름량을 조절하여 "toroidal"형태의 플라즈마도 얻을 수 있으나 분석학적 능력은 오히려 감소되었다. Glass Frit Nebuliser를 이용하여 분석하였을 때 금속 원소는 10~100 ppb 근처의 검출한계를 보였고 비금속원소인 염소의 경우는 50ppm근처의 검출한계를 보였다.

• 산업기술연구
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• 제19권
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• pp.217-226
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• 1999

A single phase to three phase power converter with cost effective and simple structure is proposed. The converter consists of rectifier and inverter. The rectifier is composed of a half wave rectifier, a dc link capacitor, and a current limiting inductor, and the inverter is of only two switches with PWM control. For negative sequence operation the inverter output voltage leads the line input by $60^{\circ}$, and for positive sequence operation the inverter output voltage leads by $60^{\circ}$. We can see that positive sequence operation shows higher output voltage, slight harmonic distortion(2%), and better performances such as high efficiency and high power factor. A mathematical model for system analysis is provided, and specifications for selection and control scheme both for start-up and for steady state are analyzed. comparison and operational limits of positive and negative sequence operation are performed, and simulations and experiments are executed to verify the proposed.

• Journal of Advanced Marine Engineering and Technology
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• 제24권5호
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• pp.42-51
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• 2000

The performances of the simple expansion, perforated tube, and conical-connector type as an exhaust muffler are shown in this study. Applying a model in which the method of four-pole parameter is used makes theoretical estimation of the insertion loss. Experiment is performed for the measurement of the insertion loss under four cases according to the variation of the tail pipe length. By comparing the theoretical prediction with the experimental results, the validity of the modeling using the method of four-pole parameter is verified. The personal computer simulation programs for the above mentioned theory on the muffler design have been developed and exhaust sound level measurements have been carried out for simple expansion muffler, conical-connector muffler, perforated tube mufflers and the combined type of conical-connector and simple expansion muffler. The measured results for attenuation characteristics of noise for each muffler are compared with the computed theoretical results to verity the confidence and applicable limits of the theoretical equation derived.

• 전기학회논문지
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• 제67권8호
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• pp.1047-1054
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• 2018

This paper proposed the strategies for controlling both the heater temperature and the output voltage of a single-phase inverter for the heat treatment. The single-phase inverter system for the heat treatment controls the heater temperature to its reference one, and also it limits the inverter output voltage to 60 V for safety. The stability may be deteriorated due to the large time constant difference between the heater temperature and inverter output voltage. In order to ensure the stability, a hysteresis on/off control approach for the heater temperature control is adapted, and both the open-loop and the closed-loop control strategies of the output voltage are suggested. The performances for the proposed strategies are demonstrated with the experiments.

• 대한기계학회논문집A
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• 제29권11호
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• pp.1509-1517
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• 2005

This paper presents the two degree-of-freedom(DOF) planar parallel mechanism called 2R$\underline{P}$R-RP manipulator, whose degree-of freedom is dependent on a passive constraining leg connecting the base and the platform. First, the kinematic analysis of the mechanism is performed analytically: the inverse and forward kinematic problems are solved in the closed font the practical workspace is systematically derived, and all of the singular configurations are examined. Then, in order to determine the geometric parameters and the operating limits of the actuators, the optimization of the mechanism is performed considering its dexterity and stiffness. Finally, the kinematic performances of the optimized mechanism are evaluated through comparing to the 5-bar parallel manipulator.