• Bulletin of the Society of Naval Architects of Korea
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• v.21 no.4
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• pp.29-39
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• 1984

In this paper, the membrane and buckling analysis of beams with various shaped brackets is performed by using the finite element method. From the viewpoint of minimum structural weight, a optimum design method to determine the optimal shapes and scantling of brackets under design load is proposed by investigating the effects of beam depth, bracket length and aspect ratio on the structural weight. Also optimal design data and charts for the brackets to support transverse girders or web frames of actual ships are provided. By the present design method, it is possible to perform optimum design of brackets used in actual ships, which could result in considerable reduction of structural weight or cost, increase of dead weight and service speed of ships.

• KSBB Journal
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• v.6 no.2
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• pp.147-156
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• 1991

Diazotized chitin (CHITN) was synthesized reacting with NaN3 and HCl to alkaline hydrolyzed chitin for the support of immobilized enzyme. Immobilized $\beta$-glucosidase on diazotized chitin(CHITN-Gase) was produced reacting with glutaraldehyds as bifunctional reagent. CHITN-Gase activities were determined reacting with p-nitrophenol-$\beta$-D-glucopyranoside in plug flow reactor as a reference. Optimum temperature, optimum pH, reaction constant and deactivation rate were determined with variation of flow rate and H/D. The particle size of immobilized enzyme in the best was, 35 mesh (CHITN35-Gase). The optimum conditions of immobilized enzyme were $70^{\circ}C$ in temperature and 5.0 in pH. Diameter and flow rate of plug flow reactor in the best was 8.5mm in diameter and 0.8ml/min in flow rate. Reaction constant was mainly influenced by electrostatic force. The best glucose hydrolizing activities of CHITN3 5-Gase was 3.34$\times$10-5 M/1. while that of native-$\beta$-glucosidase was 2.44$\times$10-5 M/1.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.3
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• pp.195-201
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• 2013

In this paper, we present optimization technique for the response time of DVR (Dynamic Voltage Restorer) and the possible compensation range of voltage dip by the DVR system. To protect 3-phase phase-controlled rectifier from voltage dip, DVR system needs to have optimum response time as an important design factor. Although the fast response time of DVR ensures wider range of voltage dip, DVR controller has so high cost and poor stability. This paper proposes DVR system with optimum response time required for certain intensity of voltage dips and good stability to support possible compensation range of voltage dip. Proposed technique showed optimum response time and good stability for overall system. We believe that proposed technique is reliable and useful in DVR design.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.4_2
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• pp.627-635
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• 2020

In this study, the optimal support span determination of pipeline system was carried out in consideration of the effects of seismic loads. The theoretical support and structural analysis were used to determine the optimal support span of piping system according to pipe diameter using theoretical and structural deflection criteria. The reliability of the analysis results was secured by comparing the structural and theoretical results. In particular, the optimum support span of piping system was obtained by considering the effects of seismic load, and the optimal support span of pipe diameter and piping system tended to be proportional to each other. When considering the effects of earthquakes on different pipe diameters(300~2,500mm), the span length is reduced by up to 48% at the allowable stress criterion, and the pipe span length is reduced by up to 5.9% at the deflection criterion. It can be seen that the effect of the seismic load on the determination of the piping span length has a greater effect on the stress than the displacement.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2001.01a
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• pp.352-357
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• 2001

This study presents an analysis of healthcare quality indicators using data mining for developing quality improvement strategies. Specifically, important factors influencing the inpatient mortality were identified using a decision tree method for data mining based on 8,405 patients who were discharged from the study hospital during the period of December 1, 2000 and January 31, 2001. Important factors for the inpatient mortality were length of stay, disease classes, discharge departments, and age groups. The optimum range of target group in inpatient healthcare quality indicators were identified from the gains chart. In addition, a decision support system was developed to analyze and monitor trends of quality indicators using Visual Basic 6.0. Guidelines and tutorial for quality improvement activities were also included in the system. In the future, other quality indicators should be analyze to effectively support a hospital-wide continuous quality improvement (CQI) activity and the decision support system should be well integrated with the hospital OCS (Order Communication System) to support concurrent review.

• Geomechanics and Engineering
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• v.17 no.3
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• pp.271-278
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• 2019

In recent years, the crack accidents of earth and rockfill dams occur frequently. It is urgent to study the tensile strength and tensile failure mechanism of the gravelly soil in the core for the anti-crack design of the actual high earth core rockfill dam. Based on the self-developed uniaxial tensile test device, a series of uniaxial tensile test was carried out on gravelly soil with different gravel content. The compaction test shows a good linear relationship between the optimum water content and gravel content, and the relation curve of optimum water content versus maximum dry density can be fitting by two times polynomial. For the gravelly soil under its optimum water content and maximum dry density, as the gravel content increased from 0% to 50%, the tensile strength of specimens decreased from 122.6 kPa to 49.8 kPa linearly. The peak tensile strain and ultimate tensile strain all decrease with the increase of the gravel content. From the analysis of fracture energy, it is proved that the tensile capacity of gravelly soil decreases slightly with the increasing gravel content. In the case that the sample under the maximum dry density and the water content higher than the optimum water content, the comprehensive tensile capacity of the sample is the strongest. The relevant test results can provide support for the anti-crack design of the high earth core rockfill dam.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.9 s.240
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• pp.1199-1208
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• 2005

Nowadays, it is performed actively to optimize by using an approximate model. This is called the approximate optimization. In addition, the sequential approximate optimization (SAO) is the repetitive method to find an optimum by considering the convergence of an approximate optimum. In some recent studies, it is proposed to increase the fidelity of approximate models by applying the sequential sampling. However, because the accuracy and efficiency of an approximate model is directly connected with the design area and the termination criteria are not clear, sequential sampling method has the disadvantages that could support an unreasonable approximate optimum. In this study, the SAO is executed by using trust region, Kriging model and Optimal Latin Hypercube design (OLHD). Trust region is used to guarantee the convergence and Kriging model and OLHD are suitable for computer experiment. finally, this SAO method is applied to various optimization problems of highly nonlinear mathematical functions. As a result, each approximate optimum is acquired and the accuracy and efficiency of this method is verified by comparing with the result by established method.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1162-1170
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• 2011

Since there is 70% of the land in South Korea is forest, tunnel constructions by blasting are common for building railways and roads. The damage to the bedrock and the development of overbreak near the face of the tunnel during the blasting directly affect the safety of the tunnel and the maintenance after the construction. Therefore, there is a need to investigate the damage zone in the bedrock after the blasting. The damage zone changes the properties of the bedrock and decreases the safety. Especially, the coefficient of permeability of the damaged bedrock increases dramatically, which is considered very important in construction. There is a lack of research on the damage that bedrock is received with respect to the amount of explosives in blasting, which is required for the design of optimum support in blast excavation that maximizes the support of the bedrock. Therefore, in this research, numerical analysis was performed based on the field experiment data in order to understand the mechanical characteristics of the bedrock after to the blast load and to analyze the damage that the bedrock receives from the blast load. In addition, a method was proposed for selecting the optimum blast pressure for train tunnel design with respect to the damage zone.

• Journal of KSNVE
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• v.10 no.5
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• pp.783-791
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• 2000

This describes a study on the support location optimizations of the beams using the genetic algorithm and the sensitivity analysis. The genetic algorithm is a probabilistic method searching the optimum at several points simultaneously and requiring only the values of the object and constraint functions. It has therefore more chances to find the global solution and can be applied to the various problems. Nevertheless, it has such a shortcoming that it takes too many calculations, because it is ineffective in local search. While the traditional method using sensitivity analysis is of great advantage in searching the near optimum. thus the combination of the two techniques will make use of the individual advantages, that is, the superiority in global searching form the genetic algorithm and that in local searching form the sensitivity analysis. In this thesis, for the practical applications, the analysis is conducted by FEB ; and as the shapes of structures are taken as the design variation, it requires re-meshing for every analysis. So if it is not properly controlled, the result of the analysis is affected and the optimized solution amy not be the real one. the method is efficiently applied to the problems which the traditional methods are not working properly.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.7 s.112
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• pp.690-696
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• 2006

Thickness of damping layer in sandwich plate needs to be optimized in order to make modal loss factor of the sandwich plate maximum. Since previous studies were interested in noise reductions over high frequency range, the modal properties were derived based on simply supported boundaries. This conventional formula is approximately applicable to other boundary conditions over high frequency range only. The purpose of this study is to propose a method to determine optimum damping layer thickness of sandwich plate for maximum modal damping in low frequency range when the boundary condition is not a simple support. The conventional RKU equation based on simply supported boundary is modified to reflect other boundary conditions and the modified RKU equation is subsequently applied to determine the optimum damping layer thickness for arbitrary conditions. In order to reflect frequency-dependent characteristics of elastic modulus of the damping layer, an iteration method is proposed in determining the modal properties. Test results on sandwich plates for optimum damping layer thickness are compared with predictions by the proposed method and conventional method.