• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.3 s.258
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• pp.355-364
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• 2007

Multidisciplinary design optimization based on independent subspaces (MDOIS) is a simple and practical method that can be applied to the practical engineering MDO problems. However, the current version of MDOIS does not handle the common design variables. A new version of MDOIS is proposed and named as MDOIS/2006. It is a two-level MDO method while the original MDOIS is a single-level method. At first, system analysis is performed to solve the coupling in the analysis. If the termination criteria are not satisfied, each discipline solves its own design problem. Each discipline in the lower level solves the problem with common design variables while they are constrained by equality constraints. In the upper level, the common design variables of related disciplines are determined by using the optimum sensitivity of the objective function. To validate MDOIS/2006, mathematical problem and NASA test bed problem are solved. The results are compared with those from other MDO methods. Finally, MDOIS/2006 is applied to flow patterner design and shows that it can be successfully applied to the practical engineering MDO problem.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.840-845
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• 2004

The reliability analysis for nonnormal distributions using the three level DOE(design of experiments) method was developed by Seo and Kwak in 2002. Although this method estimates only up to the first four moments(mean, standard deviation, skewness, and kurtosis) of the system response function, the result and the type of probability distribution determined by using the Pearson system are shown very good. However the accuracy is low in case of nonlinear performance function and sometimes, the level calculated is outside of the region in which the random variable is defined. In this article we suggest a modified three level DOE method to overcome these weaknesses and to obtain optimum choice for 3 levels and weights to handle nonnormal distributions. Furthermore we extend it to finding the optimum choice for 5 levels and weights to increase the accuracy in case of nonlinear performance function. A systematic procedure for reliability analysis is then proposed by using the Pearson system.

• Journal of the Institute of Convergence Signal Processing
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• v.10 no.4
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• pp.274-279
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• 2009

The flow of a universal system-level design methodology consists of system specification, system-level hardware/software partitioning, co-design, co-verification using virtual or physical prototype, and system integration. In this paper, verification environments based-on SystemVerilog and SystemC, one is native-code co-verification environment which makes prompt functional verification possible and another is SystemVerilog layered testbench which makes clock-level verification possible, are implemented. In native-code co-verification, HW and SW parts of SoC are respectively designed with SystemVerilog and SystemC after HW/SW partitioning using SystemC, then the functional interaction between HW and SW parts is carried out as one simulation process. SystemVerilog layered testbench is a verification environment including corner case test of DUT through the randomly generated test-vector. We adopt SystemC to design a component of verification environment which has multiple inheritance, and we combine SystemC design unit with the SystemVerilog layered testbench using SystemVerilog DPI and ModelSim macro. As multiple inheritance is useful for creating class types that combine the properties of two or more class types, the design of verification environment adopting SystemC in this paper can increase the code reusability.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.262-264
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• 2002

This paper shows the design standard of KEPCO on the contamination design for 345 kV and 154 kV transmission tower. Up to now, because the design standard of KEPCO on the insulation design contains 154 kV transmission system only, we had investigated the 343 kV system for the revision of design standard, with respect to the contamination design, we have used the same design philosophy which were adopted to the 765 kV transmission tower. In order to determine the number of insulator discs, we had investigated the withstand voltage of discs according to the level of ESDD(Equivalent Salt Deposit Density) and kinds of disc types. The TOV(Power Frequency Temporary Overvoltage) were estimated by EMTP(Electromagnetic Transient Program) for both 154 kV and 345 kV transmission system. The overvoltage level was appeared 1.35 p.u. between phase to ground for both 154 kV and 345 kV transmission system, but finally this factor was not applied to the design standard considering current design standard and economic point of view. With regard to classification of contamination area of 345 kV transmission system, we added the clean area which was not specified in the current design practise.

• Magazine of the Korean Society of Agricultural Engineers
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• v.43 no.4
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• pp.79-88
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• 2001

Agricultural facilities can be designed by conceptual preliminary primary and detailed design stages. because each stage has a different objective, it must be applied to dissimilar design and analysis level. Engineers have to judge from evaluation that is estimated agricultural resources in the conceptual design stage. Methods of computer aided design are achieved to individual functions however it is inefficient to perform entire processes of design and hard to systematically accumulate results o design. Study on the integrated structural design system has been continued. but those system have adopted “closed architecture”which is known to inflexible method for developing applications. In this study the design platform is an environment that can support to integrated design system independently and an design platform is proposed by analyzing design processes using object oriented method. The concepts of software platform have resulted from several practical ideas, OOA/OOP and related some points. This paper aims at developing the software platform of a software environment to support the design phases of the agricultural facilities.

• Tribology and Lubricants
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• v.19 no.1
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• pp.15-20
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• 2003

The purpose of the paper is to investigate the effects of design parameters on the noise of a rotor- bearing system supported in oil lubricated journal bearings. Effects of radial clearance and width of the bearing, lubricant viscosity and mass eccentricity of the rotor are also examined. Numerical results of the parametric studies are summarized through graph for the A-weighted sound pressure level of the bearing with respect to the rotational speed of the rotor. Results show that the sound pressure level of the bearing is markedly influenced by the mass eccentricity of the rotor and the radial clearance and the width of the bearing. The high viscosity of the lubricant slightly decreases the noise of the bearing, but its effect is relatively very low at high speed. The results of the paper could be an aid in the low noise design of rotor-bearing system supported in oil lubricated journal bearings.

• Korean Management Science Review
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• v.19 no.2
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• pp.75-89
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• 2002

According to the fast-paced environment of information technology and improving customer services, the design activities of logistics systems improve customer centric services and delivery performance implementing e-logistics system. The fundamental design issues that arise in the delivery system planning are optimizing the system with minimum cost and maximum throughput and service level. This study is concerned with the integrated model development of delivery system with customer responsive service level for DCM, Demand Chain Management. We used a two-step approach for this study. First, we formulated the supply. center facility planning using stochastic set-covering problem and assigned the customers to the supply center using clustering algorithm. Second, we developed vehicle delivery planning for a supply center based on GIS, GIS-VRP. Also we developed a GUI-type computer program for proposed method for supply center problem using GIS and Geo-DataBase of Busan area. The computational results showed that the proposed method was very effective on a set of test problems.

• Journal of the Society of Naval Architects of Korea
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• v.34 no.4
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• pp.119-126
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• 1997

In this parer, a protocol system is developed, which automates the sequential procedure that transforms the information of compartment generated by SIKOB, the calculation program of ship design, to the STEP format which is used as the input data of next level of ship design. The schemata representing hull form and compartment are constructed. The STEP physical files are made by instancing these schemata using the results of SIKOB. They are transmitted to the CAD system and then worked on the CAD system. It means that they could be used as the data of next level of ship design.

• International conference on construction engineering and project management
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• 2005.10a
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• pp.643-648
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• 2005

The planning process for roadway construction involves a large amount of information on design, construction methods, quantities, unit costs, production rates, and site conditions. Therefore, it is very important to acquire, manage, and process the necessary information efficiently to produce a rigorous construction plan. GIS (Geographic Information System) is a very effective tool for integrating and managing various types of information including spatial and non-spatial data required for roadway construction planning. This paper proposes a GIS-based system for improving roadway construction planning with its 'Interactive Space Scheduling' and 'Operation Level Planning' functions. The proposed system can assist construction planners in a unique way by integrating design and construction information and creating modularized design elements for space scheduling in real time. It is expected that the proposed system could improve the efficiency of roadway construction planning.

• Proceedings of the IEEK Conference
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• 2000.06b
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• pp.161-164
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• 2000

The architecture of microprocessor for a embedded system should be one that can perform more tasks with fewer instruction codes. The machine codes that high-level language compiler produces are mainly composed of specific ones, and codes that have small size are more frequently used. Extended Instruction Set Architecture (EISC) was proposed for that reason. We have designed pipe-line system for 64 bit EISC microprocessor. function level simulator was made for verification of design and instruction set architecture was also verified by that simulator. The behavioral function of synthesized logic was verified by comparison with the results of cycle-based simulator.