• Journal of the Korean Institute of Intelligent Systems
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• v.11 no.7
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• pp.615-620
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• 2001

This paper addresses the design of sliding model fuzzy-model-based controller using genetic algorithms. In general, the construction of fuzzy logic controllers has difficulties for the lack of systematic design procedure. To release this difficulties, the sliding model fuzzy-model-based controllers was presented by authors. In this proposed method, the fuzzy model, which represents the local dynamic behavior of the given nonlinear system, is utilized to construct the controller. The overall controller consists of the local compensators which compensate the local dynamic linear model and the feed-forward controller which is designed via sliding mode control theory. Although, the stability and the performance is guaranteed by the proposed method, some design parameters have to be chosen by the designer manually. This problem can be solved by using genetic algorithms. The proposed method tunes the parameters of the controller, by which the reasonable accuracy and the control effort is achieved. The validity and the efficiency of the proposed method are verified through simulations.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.2
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• pp.431-439
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• 1996

New design principles nad necessary conditions for a mechanical system have been suggested to be kept in the design process using a washing machine transmission as a model. The necessary conditions are funcitnal requirement condition and spatial arrangement condition. The design principles to satisfy the necessary conditions are the principle of sequence and the principle of expansion. Decision sequence for state variables and design varibles of various mechanicla elements have been formulated. New automatic design program for washing machine transmission has been developed observing the necessary conditions and design principles investigated in this study. It was verified to be very effective to follow the design conditions, principles nad formulated decision sequence in mechanical system design process.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.3
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• pp.151-158
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• 2002

Automotive engineers involved in a new car project use various CAD systems that are chosen based on work requirements. For example, engineers in Hyundai Motors are using Pro/Designer and Alias fur the style design, but they use CATIA to design parts and assemblies, ANSYS for FEM analysis, and Pro/Engineer to design engines. Because they use different CAD systems, they have difficulties in collaborative design. Data, which contains errors, is transferred between CAD systems. It is difficult to find out such errors in a large CAD model. An evaluation method for CAD models has been developed in this study. This diagnosis tool analyses a STEP or an IGES file generated from a CAD system, and produces a quantitative error report. The tool has been tested with actual data sets. This paper proposes an algorithm that produces mathematical error values of entities of IGES models that have geometrical data, and entities of STEP models that have topological data, and inspects every part off model. To develop this system, we have used the OpenCASCADE kernel, which is an open source kernel developed by Matra Datavision of France.

• Korean Journal of Computational Design and Engineering
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• v.4 no.4
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• pp.371-380
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• 1999

This study proposes a process information model which can integrate various activities during the product development process, the system which can manage the process. Development process information will allow designers and managers to access previous tasks readily and utilize the information in making decisions at hand. While developing products in heterogeneous and distributed environments, concurrent and collaborative designs can be achieved by STEP. The process model in this study divides the task of product development into two fundamental parts, Specific Process(SP) and Normal Process(NP). SP includes the specific information and refer to those defined by prior STEP. NP is routine process excluded from being defined as SP. Due data information can be added to manage development pace and to show delayed tasks. As two or more different processes can be linked to show the entire development flow, Static STEP information can be dynamically interlaced. Remote location operations can be incorporated on the Internet using STEP, and information can be shared. The system has been built upon a process model schema so that task stage, design history, and different development style can be managed and accessed for each component. The system has been proven efficient in information management and exchange by several scenario testings.

• Structural Engineering and Mechanics
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• v.28 no.6
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• pp.677-694
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• 2008

A vibration power minimization model is developed, based on the mobility matrix method, for a vibration isolation system consisting of a vibrating source placed on an elastic support structure through multiple resilient mounts. This model is applied to investigate the design optimization of an X-Y motion stage-based vibration isolation system used in semiconductor wire-bonding equipment. By varying the stiffness coefficients of the resilient mounts while constraining the dynamic displacement amplitudes of the X-Y motion stage, the total power flow from the X-Y motion stage (the vibrating source) to the equipment table (the elastic support structure) is minimized at each frequency interval in the concerned frequency range for different stiffnesses of the equipment table. The results show that when the equipment table is relatively flexible, the optimal design based on the proposed vibration power inimization model gives significantly little power flow than that obtained using a conventional vibration force minimization model at some critical frequencies. When the equipment table is rigid enough, both models provide almost the same predictions on the total power flow.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1999.06a
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• pp.279-284
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• 1999

This paper presents a parametric study and an optimal design of the ER-SFD supporting a rigid rotor system. An attempt is made to obtain the optimal design of an ER-SFD for a two degree-of-freedom rotor model. Such a simple model is used in order to get a better insight into the physics of the problem, A maximum whirl amplitude, supply pressure and voltage are considered, and a maximum whirl amplitude is minimized over a range of speeds and presented for some values of unbalance mass. The results presented in this paper provide important design information necessary to reduce a whirl amplitude of an ER-SFD.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2005.04a
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• pp.704-711
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• 2005

Recently Life Cycle Cost Analysis for civil infrastructures such as pavements, bridges, and dams has been emphasized However, so far, there are few systems available for life cycle cost analysis of bridges at design stage. Therefore, the objective of this paper is to develop a user-friendly life-cycle cost analysis system for LCC-effective optimal design decision making at design stage. The program is based on the proposed LCC model, formulation, analysis modules and systematic procedure that suit Korean construction conditions. It is expected that the developed system can be effectively utilized for more LCC-effective design of bridges. It is applied to an actual bridge design project in order to demonstrate its effectiveness and applicability.

• Tribology and Lubricants
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• v.17 no.3
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• pp.216-220
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• 2001

This paper presents a parametric study and an optimal design of the ER-SFD supporting a rigid rotor system. An attempt is made to obtain the optimal design of an ER-SFD for a two degree-of-freedom rotor model. Such a simple model is used in order to get a better insight into the physics of the problem. A maximum whirl amplitude, supply pressure and voltage are considered, and a maximum whirl amplitude is minimized over a range of speeds and presented f3r some values of unbalance mass. The results presented in this paper provide important design information necessary to reduce a whirl amplitude of an ER-SFD.

• International conference on construction engineering and project management
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• 2005.10a
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• pp.1144-1149
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• 2005

This paper presents how to establish the decision support model for the cooperative design in order to improve design coordination and optimize the building system. With this view, the paper presents the method that analyzes decision making participants of each building system on drawings. It also presents the combination evaluation method from the viewpoint of performance, cost and constructability to improve the decision making process in cooperative design.

• International journal of advanced smart convergence
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• v.3 no.1
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• pp.11-14
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• 2014

We have been designing human interactions for some learning support system or education system. The design is based on a symbol grounding model. The model is applicable to many learning domains using virtual reality technology. The design policy is simple and compact. In order to realize the policy we use/reuse some devices from the viewpoint of virtual reality. This paper introduces basic ideas and explains several example cases based on the idea.