• Proceedings of the KIEE Conference
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• 2007.10c
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• pp.107-109
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• 2007

This paper presents a dynamic force analysis of switched reluctance motor using 2D-transient finite element method. The main exciting of the vibration is the electiromagnetic force in the stator that is calculated Maxwell stress method. The advantage for elimation of vibration of 12/8 SRM was explained by comparing the radial force of 12/8 and 6/4 SRM in both time and frequency domain. In order to effective mitigate the vibration during turning off process, effects of different commutation method were investigated.

• Journal of Korean Institute of Industrial Engineers
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• v.30 no.3
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• pp.241-249
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• 2004

By committing to a long-term replenishment contract, suppliers can mitigate the pressure to find new customers and afford to charge a discounted price to buyers seeking to lower their purchasing costs. In this paper, we develop an analytical model from buyer's perspective for the contracting process to investigate the buyer-supplier interactions. Based on the developed model, we propose an algorithm to derive optimal strategy for the contract. We consider a system with a single buyer and a supplier in a situation where the buyer's inventory is controlled by (R, S) policy under VMI setting. According to the contract, the supplier should replenish the buyer's inventory up to a fixed level every R times during a specified period. The buyer purchases any deficient amount from a spot market at a higher price. We show by computational experiment that our proposed algorithm finds the global optimum solution.

• Journal of Electrical Engineering and Technology
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• v.9 no.6
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• pp.1873-1881
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• 2014

This paper deals with the design of multi-machine power system stabilizers (PSSs) and Static var compensator (SVC) using Modified shuffled frog leaping algorithm (MSFLA). The effectiveness of the proposed scheme for optimal setting of the PSSs and SVC controllers has been attended. The PSSs and SVC controllers designing is converted to an optimization problem in which the speed deviations between generators are involved. In order to compare the capability of PSS and SVC, they are designed independently once, and in a coordinated mode once again. The proposed method is applied on a multi-machine power system under different operating conditions and disturbances to confirm the effectiveness of it. The results of tuned PSS controller based on MSFLA (MSFLAPSS) and tuned SVC controller based on MSFLA (MSFLA SVC) are compared with the Strength pareto evolutionary algorithm (SPEA) and Particle swarm optimization (PSO) based optimized PSS and SVC through some performance to reveal its strong performance.

• Journal of the Korean Society of Safety
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• v.29 no.5
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• pp.160-165
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• 2014

The realistic cases causing severe core damage should be analyzed and arranged systematically for preparing an accident management of the specific nuclear power plant. The objective of this paper is to establish basic technical information for reactor safety and reactor building integrity management strategies in CANDU reactor severe accident. For the development of severe accident management strategies, plant specific features and behaviors must be studied by detailed analysis works. This analysis scope will serve to cover overall methods and analyzing results to understand the reactor building integrity status in the most likely severe accident sequences that could occur at CANDU reactor. Also analysis results could help prevent or mitigate severe accidents for the identification of any plant specific vulnerabilities to severe accidents using the probabilistic safety assessment (PSA) quantified results.

• Structural Engineering and Mechanics
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• v.53 no.5
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• pp.1031-1049
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• 2015

This paper highlights the role of innovative vibration control system based on two promising properties in a parallel configuration. Hybrid device consists of two main components; recentering wires of shape memory alloy (SMA) and steel pipe section as an energy dissipater element. This approach concentrates damage in the steel pipe and prevents the main structural members from yielding. By regulation of the main adjustable design parameter, an optimum performance of the device is obtained. The effectiveness of the device in passive control of structures is evaluated through nonlinear time history analyses of a five-story steel frame with and without the hybrid device. Comparing the results proves that the hybrid device has a considerable potential to mitigate the residual drift ratio, peak absolute acceleration and peak interstory drift of the structure.

• Structural Engineering and Mechanics
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• v.51 no.1
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• pp.141-162
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• 2014

The paper focuses on the dynamic response of a blast-invested glass-steel curtain wall supported by single-way pretensioned cables. In order to mitigate the critical components of the façade from severe structural damage, an innovative system able to absorb and dissipate part of the blast-induced stresses in the critical façade components is proposed. To improve the blast reliability of the studied glazing system, specifically, rigid-plastic and elastoplastic devices are introduced at the base and at the top of the vertical bearing cables. Several combinations and mechanical calibrations of these devices are numerically investigated and the most structurally and economically advantageous solution is identified. In conclusion, a simple analytical formulation totally derived from energetic considerations is also suggested for a preliminary estimation of the maximum dynamic effects in single-way cable-supported façades subjected to high-level blast loads.

• Structural Engineering and Mechanics
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• v.63 no.4
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• pp.447-456
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• 2017

The primary objective of this paper is to study the effectiveness of anchorage on the performance of shear deficient beams externally strengthened with CFRP composites. The overall behavior of the tested beams loaded up to failure, the onset of the cracking, and crack development with increased load and ductility were described. The use of CFRP composites is an effective technique to enhance the shear capacity of RC beams by using CFRP strips anchored into the tension side and from the top by 15-34% based on the investigated variables. Bonded anchorage of CFRP strips with width of 0.1h-0.3h to the beam resulted in a decrease in average interface bond stress and an increase in the effective strain of the FRP sheet at failure, which resulted in a higher shear capacity as compared with that of the U-wrapped beams without anchorage as well as delay or mitigate the sheet debonding from the concrete surface.

• Journal of Microbiology and Biotechnology
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• v.28 no.9
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• pp.1443-1446
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• 2018

In the present study, we examined whether Lactobacillus johnsonii CJLJ103 (LJ) could alleviate cholinergic memory impairment in mice. Oral administration of LJ alleviated scopolamine-induced memory impairment in passive avoidance and Y-maze tasks. Furthermore, LJ treatment increased scopolamine-suppressed BDNF expression and CREB phosphorylation in the hippocampi of the brain, as well as suppressed $TNF-{\alpha}$ expression and $NF-{\kappa}B$ activation. LJ also increased BDNF expression in corticosterone-stimulated SH-SY5Y cells and inhibited $NF-{\kappa}B$ activation in LPS-stimulated microglial BV2 cells. However, LJ did not inhibit acetylcholinesterase activity. These findings suggest that LJ, a member of human gut microbiota, may mitigate cholinergic memory impairment by increasing BDNF expression and inhibiting $NF-{\kappa}B$ activation.

• Environmental Engineering Research
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• v.21 no.4
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• pp.355-364
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• 2016

Beijing, as a cradle of modern industry and the third largest metropolitan area in China, faces more responsibilities to adjust industrial structure and mitigate carbon emissions. The purpose of this study is aimed at predicting and comparing industrial carbon emissions of Beijing in ten scenarios under different policy focus, and then providing emission-cutting recommendations. In views of various scenarios issues, system dynamics has been applied to predict and simulate. To begin with, the model has been established following the step of causal loop diagram and stock flow diagram. This paper decomposes scenarios factors into energy structure, high energy consumption enterprises and growth rate of industrial output. The prediction and scenario simulation results shows that energy structure, carbon intensity and heavy energy consumption enterprises are key factors, and multiple factors has more significant impact on industrial carbon emissions. Hence, some recommendations about low-carbon mode of Beijing industrial carbon emission have been proposed according to simulation results.

• Bulletin of the Korean Space Science Society
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• 2008.10a
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• pp.28.3-28.3
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• 2008

Contamination has the potential for degrading the performance of the optical payload beyond the limits defined by mission requirements, therefore it must be considered a risk to system performance and must be mitigated. To mitigate contamination problem, contamination budget is allocated according to the contamination requirements which is derived from contamination effect analysis. Once the contamination budget is allocated, prediction for on-ground and in-orbit contaminants amounts and cleanliness control is performed. In this article, typical contamination control for observation satellite is described.