• Proceedings of the KOR-KST Conference
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• 2003.02a
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• pp.21-71
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• 2003

Previous alignment optimization models have not adequately considered intersections and other structures such as bridges, tunnels, grade separations and interchanges which can very strongly affect alignment decisions. This paper develops comprehensive cost functions for intersections and other structures and incorporates them in recently developed highway alignment optimization models connected with genetic algorithms and geographical information systems. The result is a fast and computerized process for extracting, analyzing spatial data, evaluating candidate alignments and optimizing them. A method for locally optimizing intersections is also developed. It improves search flexibility by saving good alignments whose unacceptable crossing angles with existing roads can be fixed, Through case studies, the developed model is found to produce feasible and efficient solutions.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.10a
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• pp.279-286
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• 2002

This study is concerned wiか the practical optimum design of concrete framed structures considering serviceability - deflection, crack, fatigue. The optimizing problems of framed structure are formulated with the objective function and the constraints which take the section properties as the design variables. The objective functions are formulated as the total cost of the structures and the constraints are derived by using the criteria with respect to safety and serviceability based on the part of concrete bridge in the Korea standard code of road bridge. The SLP method is introduced to solve the formulated nonlinear programming problems in this study and tested out through the numerical examples. This developed optimizing algorithm is tested out and examined through the numerical examples for the practical use of design on the concrete framed structures. And their results are compared and analyzed to examine the possibility of optimization, the applicability and the convergency of this algorithm.

• Nuclear Engineering and Technology
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• v.29 no.1
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• pp.68-77
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• 1997

The reactor power control system is described in the fashion of the order increased LQR system. To obtain the optimal state feedback gain vectors, the weighting matrix of the performance function should be determined. Since the contentional method has some limitations, stochastic searching methods are investigated to optimize the LQR weighting matrix using the modified genetic algorithm combined with the simulated annealing, a new optimizing tool named the hybrid MGA-SA is developed to determine the weighting parameters of the LQR system. This optimizing tool provides a more systematic approach in designing the LQR system. Since it can be easily incorporated with any forms of the cost function, it also provides the great flexibility in the optimization problems.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.48 no.2
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• pp.155-164
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• 2012

The CSR rule was defined by IACS as the unified rule for a commercial ship like a bulk carrier and a tanker. It have been required more strict conditions for various parts like loading conditions, the local and girder strength, fatigue strength, FEM for the ship rule. It was changed in many parts of the ship rules. In this paper, the mid-parts of 17.5K DWT bulk carrier were optimized by the CSR rule. On the other hand, the modified artificial life algorithms with multi-object functions were developed for optimizing the scantling. It is possible to find multi-global optimum solutions in the multi-object functions. And it is faster and efficient than the artificial life algorithm. First, to be optimizing the scantling and the weight by CSR rule, that is calculated by the CSR rule. The next, the result is re-calculated by the modified artificial life algorithm with multi-object functions. The optimized results which are satisfied with the CSR rule like the minimum size and the thickness of stiffener and the minimum cost have been searched by the optimizing algorithm. And the results have been compared with the non-optimizing results.

• Journal of Technology Innovation
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• v.26 no.4
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• pp.1-28
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• 2018

With the growing number of emerging carmakers, automotive parts manufacturers have to penetrate into emerging markets. They can provide large existing carmakers with fully customized parts because of economies scale, but cannot do this for small emerging carmakers due to their small and highly volatile volume order. Once the order by an emerging carmaker is placed, a part manufacturer is exposed to high risks both of decrease in profit margin and high opportunity cost. The platform-based mass customization can be a solution for cost reduction, but the risks of volatility in volume hard to manage. Tackling this issue, we presents a method of optimizing the product portfolio to maximize profits while managing volatility of volume order by emerging carmakers at an affordable level. It is the first robust product portfolio method to keep the scaled deviation of profits at a fixed level under volume order uncertainty. Also, the effect of on the platform-based mass customization on cost is considered. This model can be a building block of conservative market penetration as well as product development strategy while minimizing the financial risks. We conducted an empirical study of a part manufacturer targeting on eighteen automobile manufacturers in North America, Europe and Asia with it powered lift gate.

• ETRI Journal
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• v.42 no.1
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• pp.118-128
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• 2020

A semitransparent photovoltaic-thermal (PV/T) air collector can produce electricity and heat simultaneously. To maximize the thermal and overall efficiency of the semitransparent PV/T air collector, its availability should be maximum; this can be determined through a Markov analysis. In this paper, a Markov model is developed to select an optimized number of semitransparent PV modules in service with five states and two states by considering two parameters, namely failure rate (λ) and repair rate (μ). Three artificial neural network (ANN) models are developed to obtain the minimum cost, minimum temperature, and maximum thermal efficiency of the semitransparent PV/T air collector by setting its type appropriately and optimizing the number of photovoltaic modules and cost. An attempt is also made to achieve maximum thermal and overall efficiency for the semitransparent PV/T air collector by using ANN after obtaining its minimum temperature and available solar radiation.

• Plant Journal
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• v.7 no.3
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• pp.65-73
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• 2011

This research has suggested a method to select pipe wall thickness by application of the value engineering to reduce the cost and quantity that are major part of construction materials. This research shows that the application of value engineering reduces the cost of piping materials by optimizing pipe wall thickness while maintaining process flow date of design pressure and design temperature. Based on this knowledge, the application of the value engineering will lead to the cost reduction and quantity reduction by effective selection of pipe wall thickness. The application of the value engineering will help the EPC companies to win a contract in the overseas plant market.

• Journal of the Korea Institute of Building Construction
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• v.4 no.2
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• pp.73-80
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• 2004

The purpose of this study was to look up the proper inventory management system in construction industry. it is important for construction company to improve competitiveness and to reduce construction cost. Lot-sizing techniques were applied to rebar procurement in apartment project. The results of this study were as follows; the method of Groff's marginal cost showed the best performance of other techniques and the method of Norman showed a similar result.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.238-239
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• 2013

It is a crucial requirement to utilize an economical battery capacity for the wind energy conversion system. In this paper, the optimal BESS capacity is determined for the wind farm whose dispatched power is assigned by the min-max dispatching method. Based on a lifetime cost function that indicates the BESS cost spent to dispatch 1kWh wind energy into grid, the battery capacity can be optimized so as to obtain the minimum system operation cost. Moreover, the battery state of charge (SOC) is also managed to be in a safe operating range to ensure the system undamaged. In order to clarify the proposed optimizing method, a 3MW permanent magnet synchronous generator (PMSG) wind turbine model and real wind speed data measured each minute are investigated.

• Journal of Electrical Engineering and Technology
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• v.7 no.6
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• pp.948-953
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• 2012

The characteristics of an induction motor vary with the number of parameters and the performance relationship between the parameters also is implicit. In case of the induction motor design, we generally should estimate many objective physical quantities in the optimization procedure. In this article, the multi objective design optimization based on genetic algorithm is applied for the three phase induction motor. The efficiency, starting torque, and material cost are selected for the objectives. The validity of the design results is also clarified by comparison between calculated results and measured ones.