• 산업기술연구
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• 제17권
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• pp.79-85
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• 1997

This paper describes a control for the high performance induction motor drive system with a wide speed operating range and proposes a robust control method independent of motor parameter variation. For the operation below the rated speed, the high performance control is achieved by using the indirect field-oriented control with a speed sensor. In the high speed regain, the field weakening region with a large variation in motor parameters, the motor drive system can obtain the robustness to motor parameter variation by switchover to the direct field-oriented control. Also, the sensorless speed control using estimated speed is achieved in very high speed region that the utilization of speed sensor pulses is limited. And from experiments using high performance 32bit DSP for 2.2[kW] and 22[kW] laboratory induction motor drive systems, it is verified that the proposed opration algorithm provided a good performance.

• 산업기술연구
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• 제22권A호
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• pp.9-17
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• 2002

This analysis is aimed to find out how the conditions of secondary air injection affects the residence time and the turbulence energy of flue gas and flow field in a small incinerator. A commercial code, PHOENICS, is used to simulate the flow field of an Incinerator. The computational grid system is constructed in a cartesian coordinate system In this numerical experiment, an independent numerical variable is the conditions of secondary air injection and dependants are the residence time of flue gas and the mean value of turbulence energy in a primary combustion chamber. The flow field and the distribution of turbulence energy are analysed to evaluate the residence time of flue gas and the turbulence energy The computational results say that the tangential injection of secondary air make the residence time much longer than the radial injection and that the radial injection of secondary make turbulence much stronger than the tangential injection.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제20권1호
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• pp.83-106
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• 2016

This paper reviews and compares three different methods for modeling incompressible and immiscible ternary fluid flows: the immersed boundary, level set, and phase-field methods. The immersed boundary method represents the moving interface by tracking the Lagrangian particles. In the level set method, an interface is defined implicitly by using the signed distance function, and its evolution is governed by a transport equation. In the phase-field method, the advective Cahn-Hilliard equation is used as the evolution equation, and its order parameter also implicitly defines an interface. Each method has its merits and demerits. We perform the several simulations under different conditions to examine the merits and demerits of each method. Based on the results, we determine the most suitable method depending on the specific modeling needs of different situations.

• 한국산학기술학회논문지
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• 제10권10호
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• pp.2628-2633
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• 2009

초소형 전자 칼럼에서 이중 편향기는 칼럼의 왜곡 수차의 최소화 및 FOV(field of view)의 극대화 효과를 위하여 사용하고 있다. 이러한 효과를 관찰하기 위하여 이중 편향기에 서로 반대로 전압을 인가한 상태에서 FOV와 주사 폭의 변화에 대한 실험을 진행하였으며, 최대 FOV와 주사 폭에 대한 적정 조건을 얻기 위한 각 편향기의 인가 전압과 전자 방출 팁 전압의 관계를 조사하였다. 또한 전자 방출 팁 전압에 의한 줌 기능의 선형성과 줌 한계를 측정하여 분석하였다.

• 산업기술연구
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• 제8권
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• pp.23-30
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• 1988

In this paper, the characteristics of electrical breakdown and TDDR (Time Dependant Dielectric Breakdown) were studied to evaluate stability and reliability of thin insulator films such as oxide and nitride. As the oxide film thickness decreased, the electrical breakdown field was increased proportioning to its reverse square root, ${d^{-\frac{1}{2}}}$. As for the temperature dependance of breakdown field, its field was inclined to decrease as temperature increased. It also showed that oxide charge (Qss) was changed by stress field and stress time. Consequently, TDDB characteristics and breakdown mechanism proved the improvement of reliability and stability and provided the accurate analysis to predict a device life time.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1992년도 가을학술발표회 논문집
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• pp.121-130
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• 1992

Assessement of comsolidation characteristics of soft soil is very important in the project of soft soil improvement. In the design step, the consolidation characteristics of soil is determined by the laboratory tests (typically oedometer test), generally. But there is big differences between the condition of laboratory test and the condition of field(in situ). the differences results in the considerable difference between the predicted and measured consolidation behavior. This article analyzed the consolidation data of the "SOFT SOIL IMPROVEMENT PROJECT of the 2nd Namdong Industrial Complex at Inchon". The project was improving the road way net work in the 2nd Namdong Industrial Complex by preloading and sand pile method. Field instrumentation was performed at 10 points which consist of pneumatic piezometers, magnetic probe extensometers, inclinometers and electronic dipmeter. The results showed that there is big difference in the laboratory predicted consolidation behavior and field consolidadion behavior. Also there was big difference in the settlement behavior and pore pressure behavior. This article investigated the above factors by comparing the settlement, pore pressure and strength at different conditions.onditions.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 E
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• pp.1788-1790
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• 1997

It is necessary to know the accurate field distribution around the high power apparatus, in designing it. To calculate the field around electrodes, we use the Charge Simulation Method(CSM) among several numerical methods and develop the new "Field Analysis System", by which we can draw the shape of electrodes, save the drawing in ascii code and apply CSM on the data. In the Field Analysis System, we try several rules for arrangement of simulation charge on CSM and consider their accuracy.

• 산업경영시스템학회지
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• 제25권6호
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• pp.36-41
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• 2002

We consider the Fuzzy clustering which is devised for partitioning a set of objects into a certain number of groups by assigning the membership probabilities to each object. The researches carried out in this field before show that the Fuzzy clustering concept is involved so much that for a certain set of data, the main purpose of the clustering cannot be attained as desired. Thus we propose a new objective function, named as Fuzzy-Entroppy Function in order to satisfy the main motivation of the clustering which is classifying the data clearly. Also we suggest Mean Field Annealing Algorithm as an optimization algorithm rather than the ISODATA used traditionally in this field since the objective function is changed. we show the Mean Field Annealing Algorithm works pretty well not only for the new objective function but also for the classical Fuzzy objective function by indicating that the local minimum problem resulted from the ISODATA can be improved.

• 산업기술연구
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• 제25권A호
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• pp.31-38
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• 2005

Recent earthquakes have shown that near-field earthquakes can produce spectral demands significantly larger than those considered in current design code. International Atomic Energy Agency (IAEA) has recently initiated a coordinated research program on safety significance of near-field earthquakes. The purpose of this program is to focus on the assessment of vulnerability of nuclear facility structures by using and adapting the best available engineering practices appropriate to evaluate the effects of near-field earthquakes. The objective of this paper is to evaluate of seismic responses of a shear building test specimen subjected to near-filed earthquakes. To achieve the objective, the seismic responses of the test specimen, evaluated by the Displacement Coefficient Method (DCM) and Nonlinear Dynamic Analysis (NDA), are compared with those by the experimental tests.

• Journal of Evidence-Based Herbal Medicine
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• 제3권1호
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• pp.19-23
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• 2010

Gyeongsangbukdo is nation's leading producer of medicinal crop. Based on this, Gyeongbuk-specific measures for the development of oriental medicine industry is proposed. The aim is the development of oriental medicine industry and regional economic in Gyeongbuk. Production, research and development, manufacturing, distribution are constructed in industrial cluster. And each step need a quality control strictly. In production field, make the seed valley of medicinal crop and Good Agricultural Practice park. In research and development field, study on efficacy of oriental medicine with Good Laboratory Practice. In manufacturing field, make industrial park for foods, dietary supplements and drugs with Good Manufacturing Practice. In distribution field, supports advanced distribution program with Good Supply Practice.