• Smart Structures and Systems
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• v.11 no.4
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• pp.387-410
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• 2013

This paper deals with the damage assessment for isolators of base-isolated building systems considering the torsion-coupling (TC) effect by establishing damage indices. The damage indices can indicate the reduction in lateral stiffness of the isolator story as explicit formulas in terms of modal parameters. In addition, the damage location, expressed in terms of the estimated damage index and eccentricities before and after damage, is also presented. Numerical analysis shows that the proposed algorithms are applicable for general base-isolated multi-story TC buildings. A procedure from the analysis of seismic response to the implementation of damage indices is demonstrated by using a numerical case. A system identification technique is employed to extract modal parameters from seismic responses of a building. Results show that the proposed indices are capable of detecting the occurrence of damage and preliminarily estimating the location of damaged isolator.

• Nuclear Engineering and Technology
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• v.27 no.5
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• pp.645-660
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• 1995

The loss of Residual Heat Removal System (RHRS) event during reduced inventory operation for the Korean Standard Nuclear Power Plants (KSNPPS) is simulated by RELAP5/MOD3 and RELAP5/MOD3.1 Tn cases are considered : Base case for an intact Reactor Coolant System (RCS) with no tent and a vent case for an open system. Comparative simulations of base case are peformed by RELAP5/MOD3 and RELAP5/MOD3. 1 computer codes. The results of too simulations are generally in good qualitative and quantitative agreement. However, since the results of RELAP5/MOD3 simulation reveals the deficiency of RELAP5/MOD3 wall heat model, the RELAP5/AOD3.1 computer code is used for the simulation of the vent case. The analysis result of base case show that two steam generators are insufficient to remove decay heat at one day after shutdown, where the RCS is closed. The RCS pressure increased continuously and reached the RCS temporary boundaries design pressure of 0.24 MPa around 4,000 seconds. In the vent case with a flow capacity equivalent to three times the capacity of Pressurizer Safety Valve (PSV), it is shown that the RCS Pressure does not reach 0.24 MPa and core uncovery does not occur until 10,000 seconds. The detailed discussions on the results of this study suggest the feasibility of RELAP5/AOD3.1 as an analysis tool for the simulation of the loss of RHRS event at reduced inventory operation. The results of this study also provide insight for the determination of proper vent capacity.

• The Journal of Information Systems
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• v.10 no.2
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• pp.5-32
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• 2001

The main goal of this research is at the development of a bundle product suggestion sub-system of an internet shopping mall for fishery products, which can reduce the search cost of user. To achieve the goal, we first study tie key factors of successful direct commerce for fishery products, and second, we design a bundle product suggestion module and its sub-module. For this, we identify the objectives of system, and write out the necessary functions of the system and models(process model, data model, dynamic model) through the analysis of user requirements. Based on the functions and models, we design user interfaces, database, processes, and knowledge base. In designing knowledge base and inferencing strategy, we consider two intelligent agent approach(optimal algorithms, heuristic rules) and suggest one more approach(case-based reasoning). The intelligent agent can be used in enhancing the suggestion of multiple fishery product simultaneously. The system analysis and design documents presented as the research results can be used to provide good guidelines to the companies who consider developing an production suggestion agents.

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.161-163
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• 2001

In this paper, a method for optimal design of PID controller using the immune algorithm(IA) has been proposed to improve the stability of A.C.-D.C. power system. To design optimal PID controller, formulation of AC-DC system equation, selection of stability analysis model, formulation immune algorithm and application model of optimal PID controller are proposed in order of the paper. In case of various disturbance, computer simulations have been performed and the proposed IA-PID controller has been compared with base controller which is conventional control technique for dynamics. From simulation results, it is demonstrated that proposed IA-PID controller has good dynamic responses about the disturbance of power system and reliability as compared with the base control.

• Proceedings of the KSR Conference
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• 2003.10c
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• pp.210-215
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• 2003

At present, communication network for subway is making use of the train radio system for main network and normally established a base station every three subway station. It is talk over the telephone between a locomotive and the traffic control for careful train service. Besides, mobile telephone equipment is using for service improve and convenience to passengers such as 011, 016, 017, 019 and what not. However, the train radio system has been occurring a various problems when a state of emergency because it is able to compose only one communication route each base station zone. We could have improving like this problems through induce the TRS(Trunked Radio System), though because have been able to compose multilateral communication route in case of linking with LCX(Leaked Coaxial) cable which is established. Therefore, we could be able to a fitting meet the emergency as train firing etc.. and efficient use of limited frequency resources.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2001.01a
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• pp.164-168
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• 2001

This paper introduces an agent system that assists in user's work on the Internet. First, the agent receives requests from the user or other agents. Since there are various kinds of requests, it is difficult to describe a completes set of request -handling rules in advance. Therefore, the agent makes a plan referring to old cases. The agent executes the plane which is a sequence of basic operation. If the agent fails to execute basic operation or to create a plan. then it makes a new plan by interacting with the user or other agent. Finally the agent stores this new case with user's evaluation score into the case base.

• Structural Engineering and Mechanics
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• v.75 no.1
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• pp.33-47
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• 2020

In this paper the dynamic behavior of an isolated building subjected to idealized near-fault pulses is investigated. The building is represented with a simple 2-DOF model. Both linear and non-linear behavior of the isolation system is considered. Using dimensional analysis, in conjunction with closed form mathematical idealized pulses, appropriate dimensionless parameters are defined and self-similar curves are plotted on dimensionless graphs, based on which various conclusions are reached. In the linear case, the role of viscous damping is examined in detail and the existence of an optimum value of damping along with its significant variation with the number of half-cycles is shown. In the nonlinear case, where the behavior of the building depends on the amplitude of the excitation, the benefits of dimensional analysis are evident since the influence of the dimensionless 𝚷-terms is easily examined. Special consideration is given to the normalized strength of the non-linear isolation system that appears to play a complex role which greatly affects the response of the 2-DOF. In the last part of the paper, a comparison of the responses to idealized pulses between a linear fixed-base SDOF and the respective isolated 2-DOF with both linear and non-linear damping is conducted and it is shown that, under certain values of the superstructure and isolation system characteristics, the use of an isolation system can amplify both the normalized acceleration and displacement of the superstructure.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.331-336
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• 2005

A lot of manufacturing knowledge and method have applied to increase manufacturing efficiency in industry field. DES(Discrete Event Simulation) is one of solution to deal with manufacturing problems in factory. Beginning of research, old maintenance system of KNR ( Korea National Railroad) and its technical problems are basically investigated. KNR has maintained railway vehicle with their own solution based on experience. Very advanced railway vehicles such as KTX (Korea Train Express) and TTX(Tilting Train Express) will be difficult to maintain with their old maintenance method. In order to apply knowledge of DES, maintenance field of railway must be considered. Imaginary maintenance machine are selected to variable of DES. Maintenance capability of each machine will be evaluated base on imaginary data from imaginary machine. The machine could be very expensive as well as difficult to replace. Target of research is minimization of number of machine in railway workshop. So basic knowledge of discrete event simulation is introduced. Then five essential stages of discrete event simulation are provided. Each maintenance case defined as event. Each event is discrete and simulated base on different case such as one maintenance line with one machine and one maintenance line with two machines in railway workshop. simple maintenance method, discrete event simulation, will be come out very powerful in complicate maintenance system and will be helpful to reduce maintenance cost as well as maintenance labor.

• Journal of the Korean Institute of Educational Facilities
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• v.19 no.1
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• pp.13-24
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• 2012

Recently, many middle and high schools are remodeling the buildings and facilities based on departmental system. This study, through analyzing on 10 remodeling cases of high school, is showing the variation before and after remodeling, space organization types, and the types of school management. This also gives us the information on the number of classrooms and teachers' rooms for each subject, the area and number of home base, and the current state of all these facilities. Furthermore, this study is comparing and analyzing the rate of use of specialized classrooms to the type of management. Through this analysis, we reach the following conclusions. l. However all the cases remodeled their buildings to implement departmental system, the methods of space composition, the numbers of the classrooms, and the status of home base are in various forms. 2. Taken as a whole, there are only few spaces used by departmental system. 3. The spaces for practical subjects such as Science and Art are inadequate than the ones for major subjects such as Languages and Mathematics. 4. A system to assign a room for a teacher records the lowest space usage rate. 5. The area of home base per one student is only $0.48m^2$, and even the area is mostly filled with lockers. The present condition of the 10 high schools which we surveyed shortly after remodeled shows that departmental system is not firmly settled down yet.

• IE interfaces
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• v.8 no.3
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• pp.249-257
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• 1995

Expert system is an effective approach for quality system to be automated and thus to be an essential integrating mechanism in any move towards CIM(Computer Integrated Manufacturing). A quality control expert system is introduced and its relationship to CIM is illustrated in a case study. Process control expert system developed by Kim and Sin[6] has been improved via ODBC(Open DataBase Connectivity) for efficient information network, graph representation using Windows API for rapid response and some new rules for identification of patterns in control charts.