• 한국태양에너지학회 논문집
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• 제29권3호
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• pp.12-18
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• 2009

The Knowledge of the solar radiation components are essential for modeling many solar energy systems. This is particularly the case for applications that concentrate the incident energy to attain high thermodynamic efficiency achievable only at the higher temperatures. In order to estimate the performance of concentrating thermal systems, it is necessary to know the intensity of the beam radiation, as only this component can be concentrated. The Korea Institute of Energy Research(KIER) has began collecting solar radiation component data since January, 2002. KIER's component data will be extensively used by concentrating system users or designers as well as by research institutes. The theoretical analysis of solar radiation as a component has compared with the experimental data obtained by the KIER station. The Result of simulation analysis shows that the annual-average daily diffuse radiation on the horizontal surface is $1,457cal/m^2$ and daily direct radiation on the horizontal surface is $1,632cal/m^2$ for all over the 16 areas in Korea.

• 한국시뮬레이션학회논문지
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• 제8권1호
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• pp.1-18
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• 1999

Current CIM systems need to correspond flexibly to the frequent change of demands of the customers and the fast changing informations about the production environment. The demands have brought forth CIM systems developed using object-oriented technology, with reusability, expansibility, and flexibility for the system components. Due to the fact that the OO-CIM system has been developed based on an incomplete data, the constructed system must be implemented to the actual surroundings to see how pertinent it is. Hence, this paper presents an OO-simulator as a means to evaluate the pertinency and the efficiency of the developed CIM system. The OO-simulator can determine the problems likely to occur when a developed CIM system is implemented to the actual site and evaluate the efficiency beforehand. Such properties will decrease the cost of CIM system development and increase the reliability of the system. This paper presents a framework for an OO-simulator composed of a virtual factory component embodying the characteristics of a virtual factory, a connector component for the interface between the CIM system and the simulator, a configuration component for modeling the constituent structure of the CIM system, and a timer component in charge of the time advance for the simulation.

• 조명전기설비학회논문지
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• 제13권4호
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• pp.96-101
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• 1999

전력계통에서 부하모델은 안정도 해석과 조류계산의 정도를 높이기 위하여 매우 중요하다. 전력계통의 모선은 전압/주파수 변화에 따라 소비형태가 다른 다양한 부하들로 구성되어 있다. 따라서 전압/주파수 변화에 따른 부하모델을 고려하지 않으면 안된다. 본 연구는 정도 높은 부하모델링을 위해 신경회로망을 사용하였다. 대표적인 주거용 부하를 선정하여 전압과 주파수를 변화시키면서 부하특성을 측정하였다. 실험에서 얻은 실적자료로 신경회로망을 이용한 개별부하모델을 구축하고, 개별부하모델과 부하구성비에 의한 집단부하 모델을 제시하였다. 또, 전력계통해석 프로그램에 적용하기 위한 수학적 모델로의 변환기법을 제시하였다.

• 전기학회논문지
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• 제67권12호
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• pp.1587-1594
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• 2018

In south korea, the government make a plan to generate the 20% of the total electrical power as renewable source like wind generation and solar generation. This plan will accelerate the increase of fault current with power industry's growth. As the increase of fault current, the superconducting fault current limiter (SFCL) has been studied. In case that the SFCL is applied in power system, it can cause the overcurrent relay (OCR)'s trip delay because of the reduced fault current. In this paper, the overcurrent relay with voltage component was suggested to improve the OCR's trip delay caused by the SFCL and compensational constant was introduced to have the trip time similar to the trip time of case without the SFCL. For conforming the effect of the suggested OCR with voltage component, the PSCAD/EMTDC simulation modeling and analysis were conducted. Through the simulation, it was conformed that the trip delay could be improved by using the suggested OCR and compensational constant.

• 산업경영시스템학회지
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• 제41권4호
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• pp.213-219
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• 2018

Mechanical components are to be produced with accurate dimensions in order to function properly in assemblies of a machine. Once designs of mechanical components are created, designers examine the designs by adopting many known experimental methods. A primary test method includes stress and strain evaluation of structural parts. In addition, fatigue test and vibration analysis are an important test method for mechanical components. Real experiments at a laboratory are established when products are manufactured. Since design changes should be done before producing the designs in factories, rapid modifications for new designs are required in production industries. FEM simulation is a proper choice for a design evaluation with speed at a detail stage in design process. This research focuses modeling and mechanical simulation of a mechanical component in order to ensure structural safety. In this paper, a universal joint, being used in driving axels of vehicles, is studied as a target component. A design model is created and tested in some ways by using commercial software of FEM. The designed component is being twisted to transmit heavy power and thus, torsional stress should be under strengths of the component's material. The next is fatigue analysis to convince fatigue cycles to be within the endurance limit of the material. Another test is a vibration analysis for rotational components. This research draws final conclusions from these test analyses and recommends whether the designed model is under safety condition in terms of mechanical structure.

• 한국정밀공학회지
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• 제14권11호
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• pp.135-146
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• 1997

This paper describes fault diagnosis method in complex system with hierachical structure similar to human body structure. Complex system is divided into unit, item and component. For diagnosing this hierarchical complex system, it is necessary to implement special neural network. Fault diagnosis system can forecast faults in a system and decide from current machine state signal information. Comparing with other diagnosis system for single fault, the developed system deals with multiple fault diagnosis comprising Hierarchical Neural Network(HNN). HNN consists of four level neural network, first level for item fault symptom classification, second level for item fault diagnosis, third level for component symptom classification, forth level for component fault diagnosis. UNIX IPC(Inter Process Communication) is used for implementing HNN wiht multitasking and message transfer between processes in SUN workstation with X-Windows(Motif). We tested HNN at four units, seven items per unit, seven components per item in a complex system. Each one neural newtork operate as a separate process in HNN. The message queue take charge of information exdhange and cooperation between each neural network.

• 인터넷정보학회논문지
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• 제6권4호
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• pp.21-35
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• 2005

소프트웨어 제품 라인은 소프트웨어 자산에 존재하는 재구성 가능한 컴포넌트를 구체화하고 미리 정의된 아키텍처를 기반으로 조립함으로써 고품질의 응용 프로그램을 효율적으로 개발하기 위한 패러다임이다. 최근 컴포넌트 기반의 여러 가지 제품 라인 개발 방법론들이 제안되었지만, 가변성 지원 컴포넌트의 구체적인 구현 기술은 제공하지 못하고 있다. 한편, 가변성을 지원하기 위한 여러 가지 구현 기술이 개발되었지만, 이러한 구현 기술은 개발 초기부터 가변성을 고려한 체계적인 분석 및 설계 방법을 제공하지 못한다. 본 논문에서는, UMI 모델링 기법을 확장한 컴포넌트 기반 제품 라인 개발 방법론인 PLUS와 컴포넌트 자동 생성 기법을 결합하여 특정 제품 생산의 효율성을 높이는 기법을 제안한다. 본 논문에서의 컴포넌트는 가변성을 지원하는 구현 부품들이 계층 구조를 이루며 각 구현 부품들은 XSLT 스크립트로 작성된다. 특성 모델에서 선택된 특성들로부터 개발자가 원하는 컴포넌트의 코드가 자동 생성되며, 마이크로웨이브 오븐 제품 라인을 사례 연구로 해서 가변성 지원 컴포넌트의 개발 프로세스를 살펴본다.

• Earthquakes and Structures
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• 제15권5호
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• pp.453-462
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• 2018

Damages to buildings affected by a near-fault strong ground motion are largely attributed to the vertical component of the earthquake resulting in column failures, which could lead to disproportionate building catastrophic collapse in a progressive fashion. Recently, considerable interests are awakening to study effects of earthquake vertical components on structural responses. In this study, detailed modeling and time-history analyses of a 12-story code-conforming reinforced concrete moment frame building carrying the gravity loads, and exposed to once only the horizontal component of, and second time simultaneously the horizontal and vertical components of an ensemble of far-field and near-field earthquakes are conducted. Structural responses inclusive of tension, compression and its fluctuations in columns, the ratio of shear demand to capacity in columns and peak mid-span moment demand in beams are compared with and without the presence of the vertical component of earthquake records. The influences of the existence of earthquake vertical component in both exterior and interior spans are separately studied. Thereafter, the correlation between the increase of demands induced by the vertical component of the earthquake and the ratio of a set of earthquake record characteristic parameters is investigated. It is shown that uplift initiation and the magnitude of tensile forces developed in corner columns are relatively more critical. Presence of vertical component of earthquake leads to a drop in minimum compressive force and initiation of tension in columns. The magnitude of this reduction in the most critical case is recorded on average 84% under near-fault ground motions. Besides, the presence of earthquake vertical components increases the shear capacity required in columns, which is at most 31%. In the best case, a direct correlation of 95% between the increase of the maximum compressive force and the ratio of vertical to horizontal 'effective peak acceleration (EPA)' is observed.

• 한국정보과학회논문지:소프트웨어및응용
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• 제29권10호
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• pp.703-725
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• 2002

컴포넌트는 소프트웨어 개발의 복잡성을 감소시키는 효과적인 방법으로 평가되고 있다. 그러나 소프트웨어 개발 시 컴포넌트를 사용하여 기간 단축과 비용 절감 효과를 얻기 위해서는 컴포넌트의 재사용성이 향상되어야 한다. 업무 단위로 컴포넌트를 설계하여 컴포넌트 안에 업무 워크플로우를 포함하는 것은 컴포넌트의 재사용성을 향상시키는 효과적인 방법이다. 워크플로우가 내장된 컴포넌트는 업무 단위로 재사용되기 때문에 개발 기간 단축과 비용 절감 효과가 크다. 몇 몇 컴포넌트 방법론에서 워크플로우를 내장한 컴포넌트 설계 기법의 필요성을 제시했다. 그러나 컴포넌트 개발에 적용하기 위해서는 좀 더 실용적이고 구체적인 기법이 요구된다. 본 논문에서는 컴포넌트를 통한 워크플로우의 재사용을 위해 패밀리 멤버간의 가변적인 워크플로우를 컴포넌트에 내장하여 재사용성을 높이는 기법을 제안한다. 제시된 기법은 워크플로우와 워크플로우 가변성에 대한 정형명세를 통해 복잡한 워크플로우의 설계를 단순화한다. 또한 정형 명세를 통해 워크플로우 가변성 간의 불일치를 해결하고 가변성의 결합도를 낮춘다. 정형 명세와 UML을 사용한 컴포넌트 모델링의 산출물은 컴포넌트 구현 소스 코드를 자동으로 생성하는 것을 돕는다. 따라서 제시된 설계 기법은 개발자의 생산성을 높이고 컴포넌트의 재사용성을 향상시킨다. 본 논문에서는 설계 기법과 함께 예제를 통해 컴포넌트 워크플로우 명세와 설계 기법의 타당성을 입증한다.

• 한국환경과학회지
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• 제28권1호
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• pp.107-123
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• 2019

The aerosol chemical components in $PM_{2.5}$ in several regions (Seoul, Busan, Daejeon, and Jeju Island) were investigated with regard to their concentration characteristics and optical properties. The optical properties of the various aerosol components (e.g., water-soluble, insoluble, Black Carbon (BC), and sea-salt) were estimated using hourly and daily aerosol sampling data from the study area via a modeling approach. Overall, the water-soluble component was predominant over all other components in terms of concentration and impact on optical properties (except for the absorption coefficient of BC). The annual mean concentration and Aerosol Optical Ddepth (AOD) of the water-soluble component were highest in Seoul (at the Gwangjin site) ($26{\mu}g/m^3$ and 0.29 in 2013, respectively). Further, despite relatively moderate BC concentrations, the annual mean absorption coefficient of BC ($21.7Mm^{-1}$) was highest in Busan (at the Yeonsan site) in 2013, due to the strong light absorbing ability of BC. In addition, high AODs for the water-soluble component were observed most frequently in spring and/or winter at most of the study sites, while low values were noted in summer and/or early fall. The diurnal variation in the AOD of each component in Seoul (at the Gwangjin site) was slightly high in the morning and low in the afternoon during the study period; however, such distinctions were not apparent in Jeju Island (at the Aweol site), except for a slightly high AOD of the water-soluble component in the morning (08:00 LST). The monthly and diurnal differences in the AOD values for each component could be attributed to the differences in their mass concentrations and Relative Humidities (RH). In a sensitivity test, the AODs estimated under RH conditions of 80 and 90% were factors of 1.2 and 1.7 higher, respectively, than the values estimated using the observed RH.