• Mycobiology
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• v.39 no.3
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• pp.174-181
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• 2011

The purpose of the present study was to investigate the influence of cultural and environmental parameters affecting the growth and bioactive metabolite production of the rare strain VUK-10 of actinomycete Pseudonocardia, which exhibits a broad spectrum of in vitro antimicrobial activity against bacteria and fungi. Production of bioactive metabolites by the strain was high the in modified yeast extract-malt extract-dextrose (ISP-2) broth, as compared to other tested media. Glucose (1%) and tryptone (0.25%) were found to be the most suitable carbon and nitrogen sources, respectively, for optimum production of growth and bioactive metabolites. Maximum production of bioactive metabolites was found in the culture medium with initial pH 7 incubated with the strain for four days at $30^{\circ}C$, under shaking conditions. This is the first report on the optimization of bioactive metabolites by Pseudonocardia sp. VUK-10.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1224-1228
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• 2009

The korean tilting train can increase the whole operating speed at a curved railroad, reducing the lateral acceleration with the tilting mechanism unlike the train developed before. However, increasing operating speed on the curved section, may cause safety problem of train travel. In general, a suspension system has important effects on driving safety. Therefore, optimization of suspension system is necessary to secure the safety of the tilting train. In this study, the tilting train suspension system has been optimized using Design of Experiments (DOE). First, the design parameter is selected using sensitivity analysis. A lateral acceleration which affects on the driving safety is chosen as the objective function. And the Design of Experiments (DOE) is used for optimization. As a result, new design parameters which show better performance than the existing suspension system has been suggested.

• Nuclear Engineering and Technology
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• v.43 no.4
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• pp.383-390
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• 2011

Nuclear power has become an essential part of electricity generation to meet the continuous growth of electricity demand. A Sodium-cooled Fast Reactor (SFR) was developed to extend uranium resource utilization under a growing nuclear energy scenario while concomitantly providing a nuclear waste management solution. Key questions in this scenario are when to introduce SFRs and how many reactors should be introduced. In this study, a methodology using Linear Programming is employed in order to quantify an optimized growth pattern of a nuclear energy system comprising light water reactors and SFRs. The optimization involves tradeoffs between SFR capital cost premiums and the total system U3O8 price premiums. Optimum nuclear growth patterns for several scenarios are presented, as well as sensitivity analyses of important input parameters.

• Management Science and Financial Engineering
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• v.18 no.2
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• pp.23-27
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• 2012

The problem of jointly determining a robust optimal bundle of price and order quantity for a retailer in a single-retailer, single supplier, single-product supply chain is considered. Demand is modeled as a decreasing power function of product price, and unit purchasing cost is modeled as a decreasing power function of order quantity and demand. Parameters defining the two power functions are uncertain but their possible values are characterized by ellipsoids. We extend a previous study in two ways; the purchasing cost function is generalized to take into account the economies of scale realized by higher product demand in addition to larger order quantity, and an exact transformation into an equivalent convex optimization program is developed instead of a geometric programming approximation scheme proposed in the previous study.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.9 s.90
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• pp.819-826
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• 2004

A multi-step optimum strategy for the selection of the locations and directions of strain gauges is proposed in this paper to capture at best the modal response of blade in a series of modes on fan blades. It is consist of three steps including two pass reduction step, genetic algorithm and fine optimization to find the locations-directions of strain gauges. The optimization is based upon the maximum signal-to-noise ratio(SNR) of measured strain values with respect to the inherent system measurement noise, the mispositioning of the gauge in location and gauge failure. Optimal gauge positions for a fan blade is analyzed to prove the effectiveness of the multi-step optimum methodology and to investigate the effects of the considering parameters such as the mispositioning level, the probability of gauge failure, and the number of gauges on the optimal strain gauge position.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.2
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• pp.382-390
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• 2009

This paper newly proposes a modular type dynamic encoding algorithm for searches (DEAS) which partitions the whole parameters into several modules and carries out exhaustive DEAS for each module. uDEAS is used to measure parameter sensitivities to the cost function, and the variables whose sensitivities are similar are grouped to make a module. The proposed optimization method is applied to optimal trajectory generation for biped walking of a humanoid. and the optimization result is compared with those of the former versions of DEAS.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.12
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• pp.2322-2329
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• 2008

In this study, we introduce the design methodology of an optimized fuzzy cascade controller with the aid of particle swarm optimization(PSO) for ball & beam system. The ball & beam system consists of servo motor, beam and ball, and remains mutually connected in line in itself. The ball & beam system determines the position of ball through the control of a servo motor. We introduce the fuzzy cascade controller scheme which consists of the outer(1st) controller and the inner(2nd) controller as two cascaded fuzzy controllers, and auto-tune the control parameters(scaling facrors) of each fuzzy controller using PSO. For a detailed comparative analysis from the viewpoint of the performance results and the design methodology, the proposed method for the ball & beam system which is realized by the fuzzy cascade controller based on PSO, is presented in comparison with the conventional PD cascade controller based on serial genetic alogritms.

• Proceedings of the KIEE Conference
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• 1998.11b
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• pp.493-495
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• 1998

Robust design is one method to make manufacturing less sensitive to manufacturing process. Also it is cost effective technique to improve the quality process. This method uses statistically planned experiments to vary settings of important process control parameters. In this paper we apply fuzzy optimization and fuzzy logic system to robust design concept. First a method which uses fuzzy optimization in obtaining optimum settings by measured data from experiments will be presented. Second, fuzzy logic system is made to reduce experiments using experiments results consisted with key control parameter combinations. Then optimum parameter set points are obtained by the descrebed first fuzzy optimization method after prediction the results of each parameter combinations considering each control parameter variations by nonsingleton fuzzy logic system concept.

• ETRI Journal
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• v.37 no.5
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• pp.906-916
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• 2015

High-speed I/O channels require adaptive techniques to optimize the settings for filter tap weights at decision feedback equalization (DFE) read channels to compensate for channel inter-symbol interference (ISI) and crosstalk from multiple adjacent channels. Both ISI and crosstalk tend to vary with channel length, process, and temperature variations. Individually optimizing parameters such as those just mentioned leads to suboptimal solutions. We propose a joint optimization technique for crosstalk cancellation (XTC) at DFE to compensate for both ISI and XTC in high-speed I/O channels. The technique is used to compensate for between 15.7 dB and 19.7 dB of channel loss combined with a variety of crosstalk strengths from $60mV_{p-p}$ to $180mV_{p-p}$ adaptively, where the transmit non-return-to-zero signal amplitude is a constant $500mV_{p-p}$.

• Smart Structures and Systems
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• v.6 no.7
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• pp.867-887
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• 2010

An energy-based variational approach is used for structural dynamic modeling of the IPMC (Ionic Polymer Metal Composites) flapping wing. Dynamic characteristics of the wing are analyzed using numerical simulations. Starting with the initial design, critical parameters which have influence on the performance of the wing are identified through parametric studies. An optimization study is performed to obtain improved flapping actuation of the IPMC wing. It is shown that the optimization algorithm leads to a flapping wing with dimensions similar to the dragonfly Aeshna Multicolor wing. An unsteady aerodynamic model based on modified strip theory is used to obtain the aerodynamic forces. It is found that the IPMC wing generates sufficient lift to support its own weight and carry a small payload. It is therefore a potential candidate for flapping wing of micro air vehicles.