• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2000년도 춘계학술대회 논문집
• /
• pp.643-646
• /
• 2000

As many industrial systems become more complex, it becomes extremely difficult to diagnose the cause of failures. This paper presents a failure diagnosis approach based on discrete event system theory. In particular, the approach is a hybrid of event-based and state-based ones leading to a simpler failure diagnoser with supervisory control capability. The design procedure is presented along with a pump-valve system as an example.

• 한국시스템다이내믹스연구
• /
• 제3권1호
• /
• pp.61-77
• /
• 2002

This paper reviews issues and methodological status of system dynamics and suggest some research agenda for its development in Korea. After reviewing some characteristics of system dynamics approach, including dynamic feedback perspective and endogenous point of view, the paper pointed out methodological characteristics of system dynamics. It seems to be the most notable characteristics of System Dynamics that it use both quantitative and qualitative approach in explaining and modelling reality. Besides, System Dynamicists rely more heavily on refutationism than instrumentalism and this allows System Dynamicists follow more strict way of scientific inquiry. For the development of System Dynamics in Korean academic circle, developing training program and curriculum, networking scattered System Dynamicist all over the country, would be the most important task.

• 한국컴퓨터산업학회논문지
• /
• 제5권4호
• /
• pp.503-510
• /
• 2004

이 논문은 모듈 프로그램 안에서 전문가 시스템 소프트웨어 유지 보수에 관한 기존 논문을 분석하고 건설 라인 공정의 문제점을 표준 시스템을 적용, 전문가 시스템으로 해결하는 과정에서 전문가 시스템 소프트웨어 프로그램의 재생성 모듈을 기술하였다. 끝으로 CES(Construction Expert System)라는 프로그램 타입 시스템을 적용 검증했고 전문가 시스템 소프트웨어 프로그램을 통해 대형 건설 과정의 유지 보수에 대한 프레임을 제시하였다.

• World Technopolis Review
• /
• 제1권2호
• /
• pp.107-117
• /
• 2012

As reflected in the title, the main objective of the paper is to explore an appropriate approach to promote technological innovation for developing countries. Aiming to this goal, the paper studies three main innovation system approaches, whose implantation is being attempted in developing countries: first, national innovation systems (NIS), which was developed in OECD countries; second, the system of innovation for development (SID), which is a concept that tries to adapt NIS to developing countries; and third, inclusive innovation which is a pro-poor innovation system. Based on the strengths and the weaknesses of each concept and their potential adaptation in developing countries, the paper proposes an integrated approach of innovation system for developing countries. Compared to developed countries, the concept of innovation system in developing countries should be more complex because it involves not only the formal sector such as enterprises, universities, research institutes, government, and financial system but it also involves NGOs, informal companies, grassroots inventors, local and indigenous knowledge, etc. The last part of the paper discusses the ideas that innovation stakeholders in developing countries can use to promote their proper innovation system.

• International Journal of Naval Architecture and Ocean Engineering
• /
• 제10권1호
• /
• pp.37-47
• /
• 2018

Dynamic simulation is critical for electrical ship studies as it obtains the necessary information to capture and characterize system performance over the range of system operations and dynamic events such as disturbances or contingencies. However, modeling and simulation of the interactive electrical and mechanical dynamics involves setting up and solving system equations in time-domain that is typically time consuming and computationally expensive. Accurate assessment of system dynamic behaviors of interest without excessive computational overhead has become a serious concern and challenge for practical application of electrical ship design, analysis, optimization and control. This paper aims to develop a systematic approach to classify the sophisticated dynamic phenomenon encountered in electrical ship modeling and simulation practices based on the design intention and the time scale of interest. Then a novel, comprehensive, coherent, and end-to-end mathematical modeling and simulation approach has been developed for the latest Medium Voltage Direct Current (MVDC) Shipboard Power System (SPS) with the objective to effectively and efficiently capture the system behavior for ship-wide system-level studies. The accuracy and computation efficiency of the proposed approach has been evaluated and validated within the time frame of interest in the cast studies. The significance and the potential application of the proposed modeling and simulation approach are also discussed.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2002년도 추계학술대회논문집
• /
• pp.902-907
• /
• 2002

An equivalent electroacoustic circuit approach of estimating the sound absorption coefficient for parallel perforated plate system is proposed. The proposed approach is validated by comparing the calculated absorption coefficients of a parallel single layer perforated plate system with the values measured by the two-microphone impedance tube method for various porosity and the number of perforated plate. The sound absorbing performances of parallel and series perforated plate systems are compared and discussed from a standpoint of frequency bandwidth with sound absorption. The proposed approach is further extended to the parallel double layer perforated plate system.

• 한국지능정보시스템학회:학술대회논문집
• /
• 한국지능정보시스템학회 2000년도 춘계정기학술대회 e-Business를 위한 지능형 정보기술 / 한국지능정보시스템학회
• /
• pp.343-346
• /
• 2000

In this paper, a novel approach to intruder detection is introduced. The approach, based on the genetic algorithms, improved detection rate of the host systems which has traditionally relied on known intruder patterns and host addresses. Rather than making judgments on whether the access is instrusion or not, the systems can continuously monitor systems with categorized security level. With the categorization, when the intruder attempts repeatedly to access the systems, the security level is incrementally escalated. In the simulation of a simple intrusion, it was shown that the current approach improves robustness of the security systems by enhancing detection and flexibility. The evolutionary approach to intruder detection enhances adaptability of the system.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2001년도 ICCAS
• /
• pp.33.1-33
• /
• 2001

We address a novel approach to identify a nonlinear dynamic system for Wiener models, which are composed of a linear dynamic system part followed by a nonlinear static part. The aim of system identification here is to provide the optimal mathematical model of both the linear dynamic and the nonlinear static parts in some appropriate sense. Assuming the nonlinear static part is invertible, we approximate the inverse function by a piecewise linear function. We estimate the piecewise linear inverse function by using the evolutionary computation approach such as genetic algorithm (GA) and evolution strategies (ES), while we estimate the linear dynamic system part by the least squares method. The results of numerical simulation studies indicate the usefulness of proposed approach to the Wiener model identification.

• 한국시뮬레이션학회:학술대회논문집
• /
• 한국시뮬레이션학회 1994년도 추계학술발표회 및 정기총회
• /
• pp.12-12
• /
• 1994

Simulation output knowledge analysis is one of problem-solving and/or knowledge adquistion process by investgating the system behavior under study through simulation . This paper describes an approach to simulation outputknowldege analysis using fuzzy neural network model. A fuzzy neral network model is designed with fuzzy setsand membership functions for variables of simulation model. The relationship between input parameters and output performances of simulation model is captured as system behavior knowlege in a fuzzy neural networkmodel by training examples form simulation exepreiments. Backpropagation learning algorithms is used to encode the knowledge. The knowledge is utilized to solve problem through simulation such as system performance prodiction and goal-directed analysis. For explicit knowledge acquisition, production rules are extracted from the implicit neural network knowledge. These rules may assit in explaining the simulation results and providing knowledge base for an expert system. This approach thus enablesboth symbolic and numeric reasoning to solve problem througth simulation . We applied this approach to the design problem of broadband communication network.

• Journal of Information Processing Systems
• /
• 제8권2호
• /
• pp.213-240
• /
• 2012

Safety critical systems, real time systems, and event-based systems have a complex set of events and their own interdependency, which makes them difficult to test ma Safety critic Safety critical systems, real time systems, and event-based systems have a complex set of events and their own interdependency, which makes them difficult to test manually. In order to cut down on costs, save time, and increase reliability, the model based testing approach is the best solution. Such an approach does not require applications or codes prior to generating test cases, so it leads to the early detection of faults, which helps in reducing the development time. Several model-based testing approaches have used different UML models but very few works have been reported to show the generation of test cases that use events. Test cases that use events are an apt choice for these types of systems. However, these works have considered events that happen at a user interface level in a system while other events that happen in a system are not considered. Such works have limited applications in testing the GUI of a system. In this paper, a novel model-based testing approach is presented using business events, state events, and control events that have been captured directly from requirement specifications. The proposed approach documents events in event templates and then builds an event-flow model and a fault model for a system. Test coverage criterion and an algorithm are designed using these models to generate event sequence based test scenarios and test cases. Unlike other event based approaches, our approach is able to detect the proposed faults in a system. A prototype tool is developed to automate and evaluate the applicability of the entire process. Results have shown that the proposed approach and supportive tool is able to successfully derive test scenarios and test cases from the requirement specifications of safety critical systems, real time systems, and event based systems.