• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 A
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• pp.227-230
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• 1993

Recently, the development of novel control methodology enables us to improve the performance of AC-machine drives by using pulse width modulation (PWM) technique. Usually, the dynamic characteristic of induction motor (IM) has been represented by the 5-th order nonlinear differential equation. This dynamics, however, can be reduced to 3-rd order dynamics by applying direct control of IM input current. This methodology concludes that it is much easier to control IM by means of the field-oriented methods employing the current controller. Therefore a precise current control is crucial to achieve a high control performance both in dynamic and steady state operations. This paper presents an adaptive fuzzy current controller with artificial neural network (ANN) for field-oriented controlled IM. This new control structure is able to adaptively minimize a current ripple while maintaining constant switching frequency. Especially the proposed controller employs neuro-computing philosophy as well as adaptive learning pattern recognizing principles with respect to variations of the system parameters. The proposed approach is applied to the IM drive system, and its performance is tested through various simulations. Simulation results show that the proposed system, compared among several known classical methods, has a superb performance.

• Applied Microscopy
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• 제44권4호
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• pp.144-149
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• 2014

A strategy for phase identification of precipitates in high Al-containing austenitic and ferritic steels using electron diffraction (ED) is studied. Comparative studies of the various Al-containing precipitates (k-carbide, $Ni_3Al$, $Fe_3Al$, FeAl) show the similarities of crystal structure and lattice parameter. However, the slight differences of lattice parameter and structure display characteristic ED patterns (EDPs) which can be identified. $L1_2$ k-carbide and $Ni_3Al$ can be differentiated by the length of ${\rightarrow}_g$ (the reciprocal lattice vector), even though they show perfectly identical shapes of EDPs. $DO_3$ $Fe_3Al$ and $B_2$ FeAl show the characteristic EDs in [110] and [112] beam directions due to the differences of Fe site occupancies in unit cells. k-carbide, $Ni_3Al$, and FeAl show also the similar EDs in [112], [112], and [110] beam directions, respectively. All the possible similarities of EDs among each phases and the strategy for phase identification are discussed on the bases of kinematical ED simulation.

• 한국항공우주학회지
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• 제39권2호
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• pp.170-177
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• 2011

본 논문은 실시간 데이터와 시간지연데이터를 함께 전송하고 비행시험 이후 두 개의 데이터를 병합하는 원격측정방식을 제안한다. 이는 비행시험 중에 원격측정데이터를 수신하는 과정에서 다중경로페이딩과 송신안테나 패턴에 의해 영향 받는 통신환경에서 오류데이터를 최소화하기 위한 것이다. 제안된 방식이 원격측정장치 설계와 데이터 병합 프로그램 개발에 적용되어졌다. 비행시험 결과 데이터를 병합하고 동기에러를 분석함으로 원격측정을 위한 그 유효성을 입증한다.

• 한국실내디자인학회논문집
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• 제25권2호
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• pp.101-111
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• 2016

As globalization proceeds, transnational property development is increasing. Vietnam has began to experience a serious housing shortage throughout the urbanization process and they try to solve this housing problem in the city by development of New Town with an excellent technique. Of these, New city, Phu My Hung (PMH) is known as a very successful example. Therefore, this study researched 145 plan of 15 Apartment complexes which were completed after 2008 to analyse the plan characteristic of internal-external of Apartment in PMH New city in Ho Chi Minh City which effected the housing development in Vietnam. We collected the data from Internet and researched the characteristic of complex and an individual unit by visiting 6 Apartment complexes directly on Aug, 2014. In PMH, apartment has pattern of Mixed-use Apartment. There are stores on the 1st ad 2nd floor and consisted of 2 or 3 small complexes. They secure enough Green Space and Community Space and control visitor access for the safety of residents. Inside space organization is mainly consisted of 3LDK+2BATH and Public space and Private space is placed separately. Also, placed the Kitchen independently and it is quiet interesting that the entrance entry into the house directly from the external space.

• 한국정보전자통신기술학회논문지
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• 제1권3호
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• pp.111-117
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• 2008

시청각 수업이나, 세미나 등에서 프로젝터와 함께 레이저 포인터와 마우스, 키보드를 같이 사용하고 있으나 레이저 포인터와 함께 마우스나 키보드를 사용 시 불편을 초래한다. 따라서 본 논문에서는 레이저 포인터의 활용도를 높이기 위해 레이저 포인터를 이동하면 그 위치를 정확히 추적하고 그 정보를 표시함으로서 마우스 기능까지 수행할 수 있는 하드웨어를 구현하였다. 시스템은 FPGA로 카메라 인터페이스를 구현하고 ARM을 이용한 영상처리 소프트웨어와 패턴 추적을 위한 소프트웨어를 제작하였다. 레이저 포인터의 정확한 위치 파악과 처리속도를 높이기 위해 하드웨어로 잡음 처리기를 구현하여 사용하였고 소프트웨어로 스펙트럼을 분석하였다. 또한 자주 나타나는 레이저 포인터의 패턴을 저장하여 정확한 추적이 가능하도록 하였다. 구현결과 20M거리 이내에서 98%의 인식률을 확인하였다.

• 농촌계획
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• 제2권2호
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• pp.67-80
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• 1996

Less Favored Area(LFA) is a newly shaped regional concept and just appearing as a new community design target, where the topogeographical, industry-locational condition and the daily living environment have been outstandingly inferior to any other regions. Community Design(CD) principles that cover a spatial order of settlements are introduced in this study when the CD concept is applied to the LFA. The study puts a great stress on the horizontal and vertical order of communal spatial units and living activities oriented to residents'socio-economic activities, on which a CD district and an inner spatial organization of community is based. Therefore the various relationships between residents' activities and particular places, such as that between agricultural production and land, access to living services and community-outer settlements, is analysed through the field study. The emphatic point is that the spatial unit and organization of community, namely settlement order is casted not only by the horizontal coverage but also by the vertical hierarchy forming a cubic-like spatial order. Applying the CD idea to LFA has limit because the CD has been oriented on urban architectural style and community participation process. Nevertheless, that has a new possibility to understand the fundamental and archetypical change of a spatial pattern of community uncovering the accumulated layer of settlement order especially in the drastically changed mountain community from past to now.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 춘계학술대회 논문집
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• pp.86-91
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• 2005

The stack, the core unit of the MCFC system, is composed of the three main parts which are the electrodes, the matrix keeping the electrolyte and the separator. Among these, the separator made of low carbon steel is manufactured by some sheet metal forming processes. The flatness of flange of the mask plate of the separator is crucial not only to enhance the stack performance but also to reduce the production cost. This study has focused on the enhancement of flatness of the mask plate flange by controlling some process parameters like the punch and die comer radii, the blank holding force, the friction coefficient and so on. The springback phenomenon occurring in the flange drawing process has been studied first using the finite element method (FEM) in order to understand what causes the springback. The distribution pattern of local longitudinal stress in the flanged part has been revealed very important in predicting the final shape of the flange. This fact has been backed up by the experimental results carried out with the developed test dies.

• Bulletin of the Korean Chemical Society
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• 제18권1호
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• pp.70-75
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• 1997

A wide range (10 < Si/V) of mesoporous vanadium silicate molecular sieves with the MCM-41 structure have been synthesized using vanadyl sulfate as the source of vanadium and characterized by XRD, 51V MAS NMR and 29Si MAS NMR. The increase of the unit cell parameter and the decrease of Q3/Q4 ratio of 29Si spectra with the vanadium content suggest the incorporation of vanadium in the framework of MCM-41 structure. 51V MAS NMR demonstrates that vanadiums in as-synthesized V-MCM-41 are present in the chemical environment of octahedra and octahedral vanadium is decreased and tetrahedral vanadium is increased inversely with raising the calcination temperature. Though the thermal treatment in rotor of hydrated sample resulted in the change from tetrahedral environment to octahedral one and the steaming and the acid treatment affect to the chemical environment of vanadium, the spectrum similar to originally calcined sample is regenerated after recalcination. This indicates that the vanadium is belong to the framework in a relatively exposed site. The best quality XRD pattern of the product of Si/V=27 may be attributable to heterogeneous nucleation mechanism. V-MCM-41's having the Si/V ratio lower than 20 are completely collapsed after calcination.

• 산업경영시스템학회지
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• 제23권60호
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• pp.37-46
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• 2000

A biomechanical model of lower extremity in seated postures was developed to assess muscular activities of lower extremity involved in a variety of foot pedal operations. The model incorporated four rigid body segments with the twenty-four muscles to represent lower extremity This study deals with quasi-static movement to investigate dynamic movement effect in seated foot operation. It is found that optimization method which has been used for modeling the articulated body segments does not predict the forces generated from biarticular muscles and antagonistic muscles reasonably. So, the revised nonlinear optimization scheme was employed to consider the synergistic effects of biarticular muscles and the antagonistic muscle effects from the stabilization of the joint. For the model validation, three male subjects performed the experiments in which EMG activities of the nine lower extremity muscles were measured. Predicted muscle forces were compared with the corresponding EMG amplitudes and it showed no statistical difference. For the selection of optimal seated posture, a physiological meaningful criterion was developed for muscular load sharing developed. For exertion levels, the transition point of type F motor unit of each muscle is inferred by analyzing the electromyogram at the seated postures. Also, for predetermined seated foot operations exertion levels, the recruitment pattern is identified in the continuous exertion, by analyzing the electromyogram changes due to the accumulated muscle fatigue.

• 설비공학논문집
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• 제16권10호
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• pp.914-922
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• 2004

In this study, measurement and analysis of energy consumption of a research building have been conducted. The energy audit procedure includes monitoring of electricity and LNG consumption over a period of three yews from 2000 to 2002. Data acquisition system for collecting energy consumption data of HVAC equipment such as chillers, fan filter units, AHUs, cooling towers, boilers, pumps, fan coil units, air compressors and etc. has been installed in a building located in Seoul. Data collected at an interval of 1 minute are analyzed for studying the energy consumption pattern of a research building. Percentage of energy consumption of all HVAC equipment is $51.0\%$ in 2000, $55.4\%$ in 2001, and $62.3\%$ in 2002, respectively. Electricity consumption of chillers accounts for $17.6\%$ of the total energy consumption, which is the largest. Annual energy consumption-rate per unit area is $840.5Mcal/m^2{\cdot}y$ in 2000, $1,064.8Mcal/m^2{\cdot}y$ in 2001, and $1,393.0Mcal/m^2{\cdot}y$ year 2002, respectively.