• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2001년도 추계학술대회 논문집
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• pp.50-54
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• 2001

Information systems development entails planning, analysis, design and construction phases. The analysis phase identifying user requirements is the most important of these phases. Since unidentified defects in the early phase causes increased work and costs as development proceeds, the quality of analysis results affects the quality of the resultant system. Major tasks in the analysis phase are data modeling and process modeling. Research on building a knowledge-based system for data modeling have been conducted much, however, not sufficiently for process modeling. As a system environment with high user interaction increases, research on process modeling methods and knowledge- based systems considering such environment are required. In this research, a process modeling framework for information systems with high user interaction is suggested and a knowledge-based system for supporting the suggested framework is implemented. A proposed model consists of the following tasks: event analysis, process analysis, and event/process interaction analysis. Event analysis identifies business events and their responses. Process analysis break down the processes of an enterprise into progressively increasing details. Decomposition begins at the function level and ends when the elementary process level is reached. Event/process interaction analysis verifies the results of process analysis and event analysis. A knowledge-based system for supporting a proposed process modeling framework is implemented in a web-based environment.

• 한국IT서비스학회지
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• 제10권4호
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• pp.47-65
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• 2011

Business organizations are asked to create new business models utilizing current technological innovations such as ubiquitous computing technology for developing new domains of business to obtain a competitive advantage and achieve a sustainable development. This study was focused on the processes for developing new and practical business models. The purpose of this study was to propose ubiquitous sport business modeling processes from the modeling framework. In particular, this study focused on developing new, pragmatic, and effective sport business models, and this new type of business is defined as 'u-sport.' For design the business model, extensive literature reviews and case studies were conducted for benchmarking the cases and expert group review was conducted for developing u-sport business model framework. The suggested business modeling processes in this study were consisted of four phases; 1) organization strategy level setting phase, 2) business strategy level setting phase, 3) business structure level setting phase, and 4) service level setting phase. The modeling processes were verified to adapt ubiquitous sport business. This designing and modeling process is expected to play a significant role on enhancing the technology-based business environments as the process mainly focuses on the service and consumer oriented approach rather than technology and suppliers oriented approach. In conclusion, establishing sport business models by adapting the service modeling process will deliver an exponential growth and development of future ubiquitous based industry.

• 조명전기설비학회논문지
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• 제21권7호
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• pp.109-116
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• 2007

다상 브러시리스 교류전동기의 역기전력 파형은 일반적으로 이상적인 정현파나 사다리꼴 형태가 아니다. 그러므로 이상적인 역기전력을 가정하는 기존의 모델로 다상 BLAC 전동기의 특성을 시뮬레이션 또는 해석하는 경우에는 많은 오차가 발생할 수 있다. 본 논문에서는 이러한 오차를 감소시키기 위해 FEA 기반의 회로 및 수식 기반의 혼합 모델링 기법을 이용한 상변수 모델을 제안하였다. FEA로부터 얻어진 역기전력 파형을 포함한 상모델의 파라미터를 사용하는 제안된 혼합 모델링기법은 임의의 역기전력 전압파형을 갖는 다상 브러시리스 교류전동기의 시뮬레이션과 해석에 사용할 수 있다. 제안한 기법을 7상 BLAC 전동기에 적용한 시뮬레이션 및 실험 결과로부터 모델의 타당성을 입증하였다.

• Journal of Welding and Joining
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• 제16권3호
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• pp.74-84
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• 1998

The microstructures of the HAZ (Heat Affected Zone) are generally different from the base metal due to rapid thermal cycle during welding process. Particuraly, CGHAZ (Coarsened Grain Heat Affected Zone) near the fusion line is the most concerned region in which many metallurgical and mechanical discontinuities have been normally generated. A computer program by the numerical formularization of phase transformation during cooling with different rates was developed to generate the CCT diagram, and to predict microstructural (phase) changes in the CGHAZ. In order to verify simulated results, isothermal and continuous cooling transformation experiments were conducted. The simulated and experimental results showed that the developed computer model could successfully predict the room temperature microstructural changes (changes in volume fraction of phases) under various welding conditions (heat input & cooling rate $(Δt_{8/5})$).

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제14권9호
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• pp.850-863
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• 2008

비즈니스 프로세스란 기업의 목표 달성을 위하여 다양한 비즈니스 규칙에 의해 정의된 상호 연관이 있는 비즈니스 기능의 집합을 의미한다. 이러한 비즈니스 프로세스 관리를 위해 많은 기업들은 프로세스 모델링 작업을 수행하게 되는데, 이러한 모델링 작업은 사람에 의해 수행되기 때문에 예기치 못한 이상 현상이 발생할 수 있게 된다. 이러한 이상 현상이 미리 검출되지 않고 프로세스 엔진에 의해 실행된다면 막대한 비용 및 손실을 초래할 수 있기 때문에 모델링 단계에서 이상 현상이 없도록 모델링을 하거나 모델링 도구 자체에서 미리 정의된 이상 현상들을 검출하는 작업이 필요하다. 본 논문에서는 비즈니스프로세스 이상 현상 검출작업에 활용될 수 있도록 모델링 단계에서 발생할 수 있는 이상 현상들을 타입에 따라 분류하고 정의하였다.

• 대한조선학회논문집
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• 제51권1호
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• pp.88-98
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• 2014

A supercavitation is modern technology that can be used to reduce the frictional resistance of the underwater vehicle. In the process of reaching the supercavity condition which cavity envelops whole vehicle body, a vehicle passes through transition phase from fully-wetted to supercaviting operation. During this phase of flight, unsteady hydrodynamic forces and moments are created by partial cavity. In this paper, analytical and numerical investigations into the dynamics of supercavitating vehicle in transition phase are presented. The ventilated cavity model is used to lead rapid supercavity condition, when the cavitation number is relatively high. Immersion depth of fins and body, which is decided by the cavity profile, is calculated to determine hydrodynamical effects on the body. Additionally, the frictional drag reduction associated by the downstream flow is considered. Numerical simulation for depth tracking control is performed to verify modeling quality using PID controller. Depth command is transformed to attitude control using double loop control structure.

• 한국연소학회지
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• 제15권3호
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• pp.15-24
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• 2010

The purpose of this study is to assess approaches to modeling coal gasification and combustion in general purpose CFD codes. Coal gasification and combustion involve complex multiphase flows and chemical reactions with strong influences of turbulence and radiation. CFD codes would treat coal particles as a discrete phase and gas species are considered as a continuous phase. An approach to modeling coal reaction in $FLUENT^{(R)}$, selected in this study as a typical commercial CFD code, was evaluated including its devolatilization, gas phase reactions, and char oxidation, turbulence, and radiation submodels. CFD studies in the literature were reviewed to show the uncertainties and limitations of the results. Therefore, the CFD analysis gives useful information, but the results should be carefully interpreted based on understandings on the uncertainties associated with the modelings of coal gasification and combustion.

• 한국군사과학기술학회지
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• 제14권5호
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• pp.818-824
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• 2011

In this paper, we proposed a phase noise model of a frequency synthesizer for a radar system. Especially, it was proposed a phase noise model in a DAS(Direct Analog Synthesizer) and a frequency up converter system using Leeson's model. The proposed phase noise model was derived from the measurement data of model 1 and evaluated by adapting to model 2 and model 3 frequency synthesizers. The prediction phase noise by modeling was totally matched to the measured data and the effective analysis of the phase noise was done in a frequency synthesizer and a frequency converter of radar system.

• ETRI Journal
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• 제26권4호
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• pp.307-314
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• 2004

The application of a discrete pseudomorphic high electron mobility transistor (p-HEMT) as a grounded switch allows for the development of low cost phase shifters and phase modulators operating in a Ku band. This fills the gap in the development of phase control devices comprising p-i-n diodes and microwave monolithic integrated circuits (MMICs). This paper describes a discrete p-HEMT characterization and modeling in switching mode as well as the development of a low-cost four-bit phase shifter and direct quadrature phase shift keying (QPSK) modulator. The developed devices operate in a Ku band with parameters comparable to commercially available MMIC counterparts. Both of them are CMOS compatible and have no power consumption. The parameters of the QPSK modulator are very close to the requirements of available standards for satellite earth stations.

• 설비공학논문집
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• 제29권12호
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• pp.663-672
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• 2017

Building information modeling (BIM) technology based on 3D modeling has been applied to the entire domestic construction industry since 2010. It can calculate quantity take-off considering construction productivity at design phase. Based on this, it is possible to improve the reliability of construction cost prediction of design phase in the process of cost estimation. However, Building Information Level (BIL) defined by Ministry of Land, Infrastructure and Transport and Public Procurement Service does not seem to offer doable environment due to the lack of detailed application items. By calculating construction cost that meets Construction Cost Estimate Accuracy by American Association of Cost Engineers (AACE) through quantity take-off and cost estimation based on 3D modeling of BIM technology, a BIL improvement proposal at design phase for Mechanical Contracts and Construction is provided here. Results showed that properties including outline and minimum specification of the main equipment, internal main piping, and internal main duct should be defined from the intermediate design phase to have reliable cost estimation.