• 제목/요약/키워드: change of requirements

검색결과 754건 처리시간 0.023초

전자식 모터제어 시스템 개발 (A Development of Electronic Motor Control Systems)

  • 이성환;이석주
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2000년도 추계학술대회 논문집 학회본부 A
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    • pp.76-78
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    • 2000
  • The previous MCC's have the demerits of high cost and much manhour for rework because they are impossible for the standardization of products and have many manual connections. The customers require the products which can operate in connection with SCADA system by digitalizing the functions of the current MCC's and are systematized with capability of remote control. To solve these disadvantages and requirements, we developed the Electronic Motor Control System according to starting type for applying to fields based on this. This system has the various functions such as protection, measurement, and communication. Using these functions, it can monitor motor status through communication with the upper system and define the circuit for lower connection cost according to starting type and shorter manufacture period by program. The development of this product results in establishment of competitive structure with domestic competition and perfect automatic monitoring through linkage with SCADA system. In addition, it provides the comparable dominancy of receiving on orders in switch gear and adaptability to change of MCC market in Japan and Europe.

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Geostatistical analyses and spatial distribution patterns of tundra vegetation in Council, Alaska

  • Park, Jeong Soo;Lee, Eun Ju
    • Journal of Ecology and Environment
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    • 제37권2호
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    • pp.53-60
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    • 2014
  • The arctic tundra is an important ecosystem in terms of the organic carbon cycle and climate change, and therefore, detailed analysis of vegetation distribution patterns is required to determine their association. We used grid-sampling method and applied geostatistics to analyze spatial variability and patterns of vegetation within a two-dimensional space, and calculated the Moran's I statistics and semivariance to assess the spatial autocorrelation of vegetation. Spatially autocorrelated vegetation consisted of moss, Eriophorum vaginatum, Betula nana, and Rubus chamaemorus. Interpolation maps and cross-correlograms revealed spatial specificity of Carex aquatilis and a strong negative spatial correlation between E. vaginatum and C. aquatilis. These results suggest differences between the species in water requirements for survival in the arctic tundra. Geostatistical methods could offer valuable information for identifying the vegetation spatial distribution.

On-line 학습 신경회로망을 이용한 열간 압연하중 예측 (Prediction for Rolling Force in Hot-rolling Mill Using On-line learning Neural Network)

  • 손준식;이덕만;김일수;최승갑
    • 한국공작기계학회논문집
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    • 제14권1호
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    • pp.52-57
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    • 2005
  • In the foe of global competition, the requirements for the continuously increasing productivity, flexibility and quality(dimensional accuracy, mechanical properties and surface properties) have imposed a mai or change on steel manufacturing industries. Indeed, one of the keys to achieve this goal is the automation of the steel-making process using AI(Artificial Intelligence) techniques. The automation of hot rolling process requires the developments of several mathematical models for simulation and quantitative description of the industrial operations involved. In this paper, an on-line training neural network for both long-term teaming and short-term teaming was developed in order to improve the prediction of rolling force in hot rolling mill. This analysis shows that the predicted rolling force is very closed to the actual rolling force, and the thickness error of the strip is considerably reduced.

On-line 학습 신경회로망을 이용한 열간 압연하중 예측 (Prediction for Rolling Force in Hot-rolling Mill Using On-line loaming Neural Network)

  • 손준식;이덕만;김일수;최승갑
    • 한국공작기계학회:학술대회논문집
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    • 한국공작기계학회 2003년도 춘계학술대회 논문집
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    • pp.124-129
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    • 2003
  • In the face of global competitor the requirements flor the continuously increasing productivity, flexibility and quality(dimensional accuracy, mechanical properties and surface properties) have imposed a major change on steel manufacturing industries. Indeed, one of the keys to achieve this goal is the automation of the steel-making process using AI(Artificial Intelligence) techniques. The automation of hot rolling process requires the developments of several mathematical models fir simulation and quantitative description of the industrial operations involved. In this paper, a on-line training neural network for both long-term teaming and short-term teaming was developed in order to improve the prediction of rolling force in hot rolling mill. This analysis shows that the predicted rolling force is very closed to the actual rolling force, and the thickness error of the strip is considerably reduced.

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인터넷전화(VoIP)서비스품질의 전략적 연구 (Strategic Study of Internet-Phone Service Quality)

  • 김호준;조재립
    • 한국품질경영학회:학술대회논문집
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    • 한국품질경영학회 2009년도 추계학술대회
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    • pp.89-94
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    • 2009
  • In the past few years with the popularization of the Internet using mobile devices such as the universal in the field of information technology has made rapid development and spread, the width and speed of change is also expected to grow much. As a result Internet telephony (VoIP) was to emerging, VoIP as a leader in next-generation converged services, the proliferation of IPTV services, including the successful introduction and subsequent convergence of the early to gauge whether the settlement is much distance in terms of importance. Therefore, this research using the Internet and telephone customer satisfaction survey, and Kano analysis is important from the perspective of the customer requirements by looking at what the Internet phone service in the development and improvement priorities are supposed to be able to stand.

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격벽판(隔壁板)의 두께에 관한 각선급협회규칙(各船級協會規則)의 비교연구(比較硏究) (A Study of the Classificationa Society Rules on The Thicknesses of The Bulkhead Platings.)

  • 황종흘;임상전
    • 대한조선학회지
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    • 제1권1호
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    • pp.3-8
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    • 1964
  • The classification society rules [1], [2], [3], [4] on the thicknesses of the bulkhead platings are represented graphically. Fig. 1 shows that every rule value for the thickness of the ordinary watertight bulkhead plating is than theoretical value calculated by Timoshenko's formula (1) for ${\sigma}_y=35,000$ psi and k=0.4998. When a flooding due to damage occurred, however, the stiffened edges would yield and clamped edges would change to plastic hinges. In such case, the maximum bending stress at the clamped edges are reduced considerably. The rule values, therefore, are supposed to be acceptable in spite of their insufficient scantlings compared with the values calculated by (2). In the ordinary watertight bulkhead platings A.B.S. Rules give the largest scantlings of all. Fig. 2 shows that A.B.S. Rules and K.R.-N.K. Rules give larger values than the calculated by (2) for deep tank bulkhead platings. But Lloyd Rules give the smaller thickness than equation (2). The special requirements for corrosion bulkhead platings are not studied here.

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신경회로망과 유전자 알고리즘을 이용한 열연두께 정도 향상 (Improvement of Thickness Accuracy in Hot-Rolling Mill Using Neural Network and Genetic Algorithm)

  • 손준식;김일수;최승갑;이덕만
    • 한국공작기계학회:학술대회논문집
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    • 한국공작기계학회 2002년도 추계학술대회 논문집
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    • pp.41-46
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    • 2002
  • In the face of global competition, the requirements fer the continuously increasing productivity, flexibility and quality (dimensional accuracy, mechanical properties and surface properties) have imposed a major change on steel manufacturing industries. The automation of hot rolling process requires the developments of several mathematical models for simulation and quantitative description of the industrial operations involved. To achieve this objectives, a new loaming method with neural network to improve the accuracy of rolling force prediction in hot rolling mill is developed. Also, Genetic Algorithm(GA) is applied to select the optimal structure of the neural network and compared with that of engineers experience. It is shown from this research that both structure selection methods can lead to similar results.

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A Simple Approach of Improving Back-Propagation Algorithm

  • Zhu, H.;Eguchi, K.;Tabata, T.;Sun, N.
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2000년도 ITC-CSCC -2
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    • pp.1041-1044
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    • 2000
  • The enhancement to the back-propagation algorithm presented in this paper has resulted from the need to extract sparsely connected networks from networks employing product terms. The enhancement works in conjunction with the back-propagation weight update process, so that the actions of weight zeroing and weight stimulation enhance each other. It is shown that the error measure, can also be interpreted as rate of weight change (as opposed to ${\Delta}W_{ij}$), and consequently used to determine when weights have reached a stable state. Weights judged to be stable are then compared to a zero weight threshold. Should they fall below this threshold, then the weight in question is zeroed. Simulation of such a system is shown to return improved learning rates and reduce network connection requirements, with respect to the optimal network solution, trained using the normal back-propagation algorithm for Multi-Layer Perceptron (MLP), Higher Order Neural Network (HONN) and Sigma-Pi networks.

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OpenFOAM : Open source CFD in research and industry

  • Jasak, Hrvoje
    • International Journal of Naval Architecture and Ocean Engineering
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    • 제1권2호
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    • pp.89-94
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    • 2009
  • The current focus of development in industrial Computational Fluid Dynamics (CFD) is integration of CFD into Computer-Aided product development, geometrical optimisation, robust design and similar. On the other hand, in CFD research aims to extend the boundaries of practical engineering use in "non-traditional" areas. Requirements of computational flexibility and code integration are contradictory: a change of coding paradigm, with object orientation, library components, equation mimicking is proposed as a way forward. This paper describes OpenFOAM, a C++ object oriented library for Computational Continuum Mechanics (CCM) developed by the author. Efficient and flexible implementation of complex physical models is achieved by mimicking the form of partial differential equation in software, with code functionality provided in library form. Open Source deployment and development model allows the user to achieve desired versatility in physical modeling without the sacrifice of complex geometry support and execution efficiency.

LED 모듈 표준 표시사항의 경제적인 평가를 위한 단일 핀 방열 블록의 냉각성능 예측 (Predicted Cooling Performance of Single Finned Heat Dissipating Block for Economic Assessment of LED Module Markings in Standards)

  • 허영준;송명호
    • 한국태양에너지학회 논문집
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    • 제35권3호
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    • pp.81-91
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    • 2015
  • LED has received intensive research attention due to its long life, high efficacy, fast response and wide colour availability, and has secured extensive application areas. However, LED chips within the modules convert only fraction of electric energy into light, and majority of supplied energy needs to be dissipated as heat, which challenges in the performance and life of the LED modules. IEC 62717 specifies the performance requirements for LED modules together with the test methods and conditions. The present study examined the influence of different design parameters on performance temperature through series of experiments and numerical simulations. The economic means to change the module performance temperature during the measurement of mandatory markings were suggested based on predicted cooling performances.