• Journal of Advanced Marine Engineering and Technology
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• 제35권8호
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• pp.1111-1116
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• 2011

비접지방식 선박에서의 접지 고장은 대지 임피던스의 불평형을 가져오고 대지전압을 상승시켜 감전이나 전기화재의 염려가 높아진다. 접지에 따른 이 같은 대지전압의 왜곡 상태는 전기안전의 측면에서 실시간으로 감시할 필요가 있으며 이 경우 대지전압의 측정치를 위상변화 감시가 가능한 벡터다이어그램으로 나타내는 것이 효과적이다. 대지전압의 상태는 중성점 위치에 의해 표시될 수 있다는 점에서 우선 측정된 대지전압 입력에 대해 벡터 평면의 중성점을 출력하는 연산과정과 알고리즘의 해석이 필요하다. 이를 토대로 본 연구에서는 매 샘플링 주기마다 대지전압을 입력하여 컴퓨터 모니터 상에 중성점과 벡터 대지전압을 출력하는 모듈을 구성한 후 실제 배전선로에서의 실험을 통해 제시한 장치의 적정성을 확인하였다.

• 소성∙가공
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• 제14권6호
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• pp.527-532
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• 2005

Among the failure modes which can occur in tube hydroforming such as wrinkling, bursting or buckling, the bursting by local instability under excessive tensile stresses is irrecoverable phenomenon. Thus, the accurate prediction of bursting condition plays an important role in producing the successfully hydroformed part without any defects. As the classical forming limit criteria, strain-based forming limit diagram (FLD) has widely used to predict the failure in sheet metal forming. However, it is known that the FLD is extremely dependant on strain path throughout the forming process. Furthermore, The application of FLD to hydroforming process, where strain path is no longer linear throughout forming process, may lead to misunderstanding for fracture initiation. In this work, stress-based forming limit diagram (FLSD), which is strain path-independent and more general, was applied to prediction of forming limit in tube hydroforming. Combined with the analytical FLSD determined from plastic instability theory, finite element analyses were carried out to find out the state of stresses during hydroforming operation, and then FLSD is utilized as forming limit criterion. In addition, the approach is verified by a series of bulge tests in view of bursting pressure and shows a good agreement. Consequently, it is shown that the approach proposed in this paper will provide a feasible method to satisfy the increasing practical demands for judging the forming severity in hydroforming processes.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 춘계학술대회 논문집
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• pp.92-96
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• 2005

Among the failure modes which can be occurred in tube hydroforming such as wrinkling, bursting or buckling, the bursting by local instability under excessive tensile stresses is irrecoverable phenomenon. Thus, the accurate prediction of bursting condition plays an important role in producing the successfully hydroformed part without any defects. As the classical forming limit criteria, strain-based forming limit diagram has widely used to predict the failure in sheet metal forming. However, it is known that the FLD is extremely dependant on strain path throughout the forming process. Furthermore, the path-dependent limitation of FLD makes the application to hydroforming process, where strain path is no longer linear throughout forming process, more careful. In this work, stress-based forming limit diagram (FLSD), which is strain path-independent and more general, was applied to prediction of forming limit in tube hydroforming. Combined with the analytical FLSD determined from plastic instability theory, finite element analyses were carried out to find out Ihe state of stresses during hydroforming operation, and then FLSD is utilized as forming limit criterion. In addition, the approach is verified with a series of bulge tests in view of bursting pressure and shows a good agreement. Consequently, it is shown that the approach proposed in this paper will provide a feasible method to satisfy the increasing practical demands for judging the farming severity in hydroforming processes.

• 정보처리학회논문지D
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• 제16D권1호
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• pp.65-72
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• 2009

현재 컴포넌트 기반 개발 기법은 재사용성과 생산성 측면에서 효과적인 소프트웨어 개발 방법으로 많은 각광을 받고 있다. 하지만 기존의 UML을 이용한 컴포넌트 기반 개발에서는 컴포넌트의 행위를 배제하고 컴포넌트 인터페이스만 참조하여 컴포넌트를 설계함으로써, 컴포넌트의 구체적인 행위에 대한 파악과 컴포넌트 간 인터페이스 호환성 보장이 불가능하다. 이에 따라 컴포넌트 설계 단계에서 컴포넌트의 행위를 상태기계 다이어그램으로 표현하고, 표현된 상태기계 다이어그램을 통해 컴포넌트의 행위 호환성을 보장할 필요가 있다. 이 연구에서는 상태기계 다이어그램으로 표현된 컴포넌트의 행위를 관찰 일치(observation equivalence)와 호출 일관성(invocation consistency)의 개념을 이용하여 행위 호환성을 검증하는 방법을 제공하고, 동적으로 이를 수행하는 도구를 개발한다.

• 한국분무공학회지
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• 제27권3호
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• pp.155-160
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• 2022

Recently, major developed countries have strengthened automobile fuel efficiency regulations and carbon dioxide emission allowance standards to curb climate change caused by global warming worldwide. Accordingly, research and manufacturing on electric vehicles that do not emit pollutants during actual driving on the road are being conducted. Several automobile companies are producing and testing electric vehicles to commercialize them, but it takes a lot of manpower and time to test and evaluate mass-produced electric vehicles with driving mileage of more than 300km on a per-charge. Therefore, in order to reduce this, a simulation model was developed in this study. This study used vehicle information and MCT speed profile of small electric vehicle as basic data. It was developed by applying Simulink, which models the system in a block diagram method using MATLAB software. Based on the vehicle dynamics, the simulation model consisted of major components of electric vehicles such as motor, battery, wheel/tire, brake, and acceleration. Through the development model, the amount of change in battery SOC and the mileage during driving were calculated. For verification, battery SOC data and vehicle speed data were compared and analyzed using CAN communication during the chassis dynamometer test. In addition, the reliability of the simulation model was confirmed through an analysis of the correlation between the result data and the data acquired through CAN communication.

• 정보처리학회논문지D
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• 제12D권4호
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• pp.569-582
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• 2005

인터넷을 통한 정보의 교류와 비즈니스가 활발해지면서 웹 기반 소프트웨어도 확대되고 있고 그만큼 품질 측면의 노력이 중요하다. 웹 컨텐츠의 링크나 웹 기반 프로그램을 검증하는 연구가 시도되었으나 다양한 웹 기반 구성 방법들을 커버하는 방법은 찾기 어려웠고 또한 적용 실험이 부족하다. 이 논문에서는 다양한 동적인 웹 기반 소프트웨어들을 타입별로 나누어 보고 동일한 방법으로 모델링 한 후 테스트 케이스를 생성하는 방법을 제안한다. 웹 기반 소프트웨어를 구성하는 개체들을 파악한 후 이를 개체 제어흐름 그래프(Object Control of Flow Graph)와 개체 관계 다이어그램(Object Relationship Diagram)으로 모델링 한다. 모델에서 테스트 경로를 파악하고 테스트 키 포인트를 구동하는 테스트 케이스를 찾는다. 제안한 방법으로 다섯 가지 타입의 웹 기반 소프트웨어를 적용하여 실용성을 보였으며 이제까지 제안된 방법과 어떤 차이를 보이는지 비교하였다.

• 한국CDE학회논문집
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• 제14권1호
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• pp.50-59
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• 2009

There are two main problems in the current PLC ladder programming practices: First, currently there are no widely adopted systematic design methods to deal with PLC based control systems in the shop floor. So, the control logic design phase is usually omitted in current PLC programming development life cycle. Second, PLC ladder logic provides only microscopic view of system processes. As a result, it is difficult for FA engineers to have overall perspectives about the interaction of system components intuitively during the verification step of logic errors. To solve these problems, this paper proposed object-oriented design and automatic generation method of PLC ladder logic. Based on the proposed method, the computer software to assist the automatic ladder logic generation is also developed.

• International Journal of Internet, Broadcasting and Communication
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• 제11권3호
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• pp.49-58
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• 2019

Efficient evidential reasoning is an important issue in the development of advanced knowledge based systems. Efficiency is closely related to the design of problems solving methods adopted in the system. The explicit modeling of problem-solving structures is suggested for efficient and effective reasoning. It is pointed out that the problem-solving method framework is often too coarse-grained and too abstract to specify the detailed design and implementation of a reasoning system. Therefore, as a key step in developing a new reasoning scheme based on properties of the problem, the problem-solving method framework is expanded by introducing finer grained problem-solving primitives and defining an overall control structure in terms of these primitives. Once the individual components of the control structure are defined in terms of problem solving primitives, the overall control algorithm for the reasoning system can be represented in terms of a finite state diagram.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.482-485
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• 2004

A Performance Based Design procedure for retrofitting the RC frame with friction dampers is described. The Capacity Diagram Method procedure is used to estimate the inelastic response of the example model. The example models were retrofitted using SBC dampers and the retrofitted example models were computation ally modeled. The results show that the performance of the retrofitted frame satisfies the target objective.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2001년도 춘계학술대회 논문집(한국공작기계학회)
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• pp.171-176
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• 2001

This paper describes the methodology of an IEC 1131-3-based control logic generator for the control system design and converting algorithm between programmable languages. The proposed control logic generator is generated based on the software model and common element with data type, variables, POUs(program organization unit) and execution control unit commonly used within programmable languages of IEC 1131-3 Standard. The generation method of object file was proposed on five programmable language based on IECI 131-3. The generation method of object file is represented as following; 1) the generation method using conversion algorithm from LD to IL with FBD(function block diagram), 2) the generation method using C code generation algorithm from SFC using the SFC execution sequence with FBD and ST(structured text). The proposed control logic generator was implemented by Visual C++ and MFC on MS-windows NT 4.0