• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1991년도 추계학술발표회 논문집 지반공학에서의 컴퓨터 활용 COMPUTER UTILIZATION IN GEOTECHNICAL ENGINEERING
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• pp.216-232
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• 1991

This Finite Element Program(TAFEM) has been developed to be able to carry out the structural analsis of tunnel section and simulate the surrounding ground behaviour due to New Austrian Tunnelling Method, of which main support is the surrounding ground, itself. The Elasto-plastic theory has been applied. The used finite elements are 8-noded isoparametric element(rock & shotcrete), 2 or 3-noded rod element(rock bolt) and infinite boundary element. The load incremental method and tangential stiffness method has been used. Associated flow rule was applied to plastic flow and yield criteria inclued not only Mohr-Coulomb but also Drucker-Prager. In this paper, Drucker-Prager yield criterion has been used. The relationship between plastic strain and stress is based on the incremental strain concept and stress-strain equation on the basis of the stress path of each gauss point has been adopted. It may be rational that rock is considered to be no-tension material, so that no-tension analysis has been adopted in accordance with the brittle fracture constitutive equation.

• JSTS:Journal of Semiconductor Technology and Science
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• 제16권2호
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• pp.204-209
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• 2016

The analyses on self-heating effect in 7 nm node non-rectangular Bulk FinFET device were performed using 3D device simulation with consideration to contact via and pad. From self-heating effect simulation, the position where the maximum lattice temperature occurs in Bulk FinFET device was investigated. Through the comparison of thermal resistance at each node, main heat transfer path in Bulk FinFET device can be determined. Self-heating effect with device parameter and operation temperature was also analyzed and compared. In addition, the impact of interconnects which are connected between the device on self-heating effect was investigated.

• 조명전기설비학회논문지
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• 제13권3호
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• pp.17-24
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• 1999

본 연구는 스피터와 마이크폰쌍을 이용하여 변압기 소음 감소를 위한 적응 능동소음제어에 있어서 스피커-증폭기-마이크로폰 경로와 스피거-마이크로폰 쌍의 동특성에 대한 이론적인 내용과 시뮬레이션을 통하여 이를 확인하였다. 또한 음향경로 내에 존재하는 마이크로폰-스피커 쌍의 전달함수를 SLS(sequential least square)알고리즘으로 추정하였으며, 추정된 전달함수에 대한 identify는 z 평면에서 안정된 극점과 영점을 갖고 있음을 확인하였다.

• 한국농공학회논문집
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• 제47권7호
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• pp.13-22
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• 2005

Main purpose of this article is to classify reservoirs corresponding to their physical characteristics, for example, dam height, dam width, age, repair-works history. First of all, data set of 13,976 reservoirs was analyzed using k means and self organized maps. As a result of these analysis, lots of reservoirs have been classified into four clusters. Factors and their critical values to classify the reservoirs into four groups have been founded by generating a decision tree. The path rules to each group seem reasonable since their survivor function showed unique pattern.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1213-1218
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• 2007

The brake judder comes from non-uniformities in the tire/wheel assembly caused by mechanical effects such as a brake torque variation (BTV). A disc thickness variation (DTV) related with the kinematic behavior of the disc was investigated a main source of BTV. In this study, a dynamic model with brake corner assembly of full vehicle using MSC.ADAMS was correlated by experiment of judder phenomenon. Judder was generated and correlated systematically by judder experiment in chassis and brake dynamometer from variation in the thickness of the disc. Also it has been found a judder transfer path and variation of the braking pressure. Through analysis of transfer function and movement of subsystem caused by BTV generation, design parameters have been found. Based on the results obtained from parameter study of suspension module, the effective design process and developed model with brake corner assembly was suggested for vibration reduction of steering wheel caused by the judder phenomenon.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1996년도 춘계공동학술대회논문집; 공군사관학교, 청주; 26-27 Apr. 1996
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• pp.100-103
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• 1996

Presented in this study is an algorithmic procedure to obtain polyhedral model from a compound surface. The compound surface in this study denotes a collection of trimmed surfaces without topological relations. The procedure consists of two main modules: CAD data interface, and surface conversion to polyhedral model. The interface module gets geometric information from CAD databases, and makes topological information by scanning the geometric information. We are investigating CATIA system as a data source system. In the surface conversion module, a shell(compound surface with topological information) is approximated to a triangular-faceted polyhedral surface model through node sampling and triangulation steps. The obtained polyhedral model should obey the vertex-to-vertex rule and meet tolerance requirements. Since the polyhedral model has a simple data structure and geometry processing for it is very efficient and robust, the polyhedral model can be used in various applications, such as surface rendering in computer graphics, FEM model for engineering analysis, CAPP for surface machining, data generation for SLA, and NC tool path generation.

• Journal of Electrical Engineering and Technology
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• 제9권6호
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• pp.2187-2193
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• 2014

In this paper, we propose a method for suppressing shaft voltage by modifying the rotor shape and the permanent magnets in interior permanent magnet type high voltage motors. The shaft voltage, which adversely affects the bearing by occurring bearing current, is induced by parasitic components and the leakage flux in motor-driven systems as well as inherent linkage flux between main magnetic flux and shaft according to rotor configuration. Thus, shaft voltage should be analyzed and considered under inverter-driven and non-inverter-driven conditions because inherent linkage flux can analyze under non-inverter-driven condition. In this study, we designed re-arrangement magnet and re-structuring rotor to minimize the shaft voltage. In addition, we optimized the proposed models. The shaft voltage suppression effect of the designed model was validated experimentally and by comparative finite element analysis.

• Steel and Composite Structures
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• 제2권5호
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• pp.397-410
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• 2002

The main aim of the present paper is to present the results of a full-scale experimental investigation to study the structural behaviour of composite steel beams. The composite beam was made of cold-formed steel section shapes filled with reinforced concrete. First a comprehensive description of the experimental results in terms of: deflections, deformations, slippage and stress levels on critical steps of the load path is presented. The experimental results were then compared to theoretical values obtained by the use of an analytical model based on ultimate limit state stress blocks. Finally, a practical application of the use of this structural solution is depicted.

• 한국군사과학기술학회지
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• 제12권3호
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• pp.266-271
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• 2009

Electronic equipments and a missile carried by heavy trucks are often subjected to vibration and shock excitation during their transportation. Electronic equipments are so vulnerable to vibration and shock input that it is necessary to know in advance the vibration level of the truck which cause the damage of equipments. Road tests of a heavy truck carrying a canister on different road conditions such as paved road, unpaved road, and washboard are performed and the effect of road conditions on the vibration characteristics are analyzed. Vibration levels were measured at various locations of the truck along the path through which vibration was transmitted. This study reveals that the velocity of the truck as well as the road surface conditions are main factors which affect the vibration levels of the truck. The power spectrum density of the measured vibration signal and the factors affecting the PSD are also analyzed in this paper.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -2
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• pp.1078-1081
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• 2002

In microcell or picocell mobile communication using cellular method, we suggested propagation prediction model which can accurately and rapidly interpret mobile communication propagation environment in urban, when subscriber service is done based on the main road in urban. Further, we simulated suggested propagation prediction model under the hypothesis of urban propagation environment of PCS mobile communication, analyzed receiving field strength by area within a cell, and finally suggested the optimal transmitting power and location condition of microcell or picocell mobile communication base station