• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.2
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• pp.125-130
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• 2011

Since conventional optimization that is classified as a deterministic method does not consider the uncertainty involved in a modeling or manufacturing process, an optimum design is often determined to be on the boundaries of the feasible region of constraints. Reliability-based design optimization is a method for obtaining a solution by minimizing the objective function while satisfying the reliability constraints. This method includes an optimization process and a reliability analysis that facilitates the quantization of the uncertainties related to design variables. Moment-based reliability analysis is a method for calculating the reliability of a system on the basis of statistical moments. In general, on the basis of these statistical moments, the Pearson system estimates seven types of distributions and determines the reliability of the system. However, it is technically difficult to practically consider the Pearson Type IV distribution. In this study, we propose an enhanced Pearson Type IV distribution based on a kriging model and validate the accuracy of the enhanced Pearson Type IV distribution by comparing it with a Monte Carlo simulation. Finally, reliability-based design optimization is performed for a system with type IV distribution by using the proposed method.

• Korean Management Science Review
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• v.14 no.1
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• pp.131-149
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• 1997

Software cost estimation is an important both for buyers and sellers(developers). We reviewed domestic and foreign researches and practices on software cost estimation with function point method comprehensively, In this paper, we derived four promising alternative function point models. They are an IFPUG(International Function Point User Group)-based model(Model I), a shorthand model for client/sever software systems(Model II), a data-oricnted model for relatively large software projects(Model III), and a general- purpose function point model for non business application softwares as well as business applications(Model IV). Empirical data shows that Model I, II, and IV are very useful function point models. In particular, model II and IV look very useful models since they are concise and accurate. These models can be incorporated in a new improved guideline for software cost estimation. General opinion survey shows that Model I, II and IV are preferable. There are no significant differences in preference between buyers and sellers. The survey also shows that users think function point method is better than step(line of code)-oriented cost estimation methods in many ways including objectivity and estimation accuracy.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.33 no.9
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• pp.347-354
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• 1984

This paper presents a method of improving the power factor and , the waveform of A.C line currents and the output waveforms of AC to DC fully bridge converter systems which is achieved by connecting CON I.II and CON III.IV in series and parallel. The basic principle of the CON I.II.III.IV's operation is simple and feasibility of thease converter is proved by experiments. CON I and CON III are constructed of natural commutation, CON II and CON IV are constructed of forced commutation. The experimental results show that the power factor and waveform of the source currents and the output waveforms are improved by the method of connecting converter in series and parallel and driving it in I, II, III, IV quadrant.

• Bulletin of the Korean Chemical Society
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• v.19 no.9
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• pp.927-933
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• 1998

Polycrystalline powder of vanadium-doped forsterite (Vδ $Mg_2SiO_4$) was synthesized by the $H_2O_2$-assisted sol-gel method. The vanadium dopant, which was added as VO$(OMe)_3$ in methanol, went through several redox reactions as the sol-gel reaction proceeded. Upon adding VO$(OMe)_3$ to a mixture of $Mg(OMe)_2$ and Si$(OEt)_4$ in methanol, V(V) reduced to V(IV). As hydrolysis reaction proceeded, the V(IV) oxidized all back to V(V). Apparently, some of the V(V) reduced to V(IV) during subsequent gelation by condensation reaction. The V(IV) remained even after heat treatment of the gel in highly oxidizing atmosphere. The crystallization of the xerogel around 880 ℃ readily produced single phase forsterite without any minor phase. Using the polycrystalline powder as feeding stock, single crystals of vanadium-doped forsterite were grown by the floating zone method in oxidizing or reducing atmosphere. The doping was limited in low level because of the high partitioning of the vanadium in liquid phase during melting. The greenish single crystal absorbed visible light of 700∼1100 nm. But, no emission was obtained in near infrared range.

• Journal of the Korean Chemical Society
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• v.31 no.2
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• pp.178-183
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• 1987

The kinetics of the reaction of $[Mo_3O_4(H_2O)_9]^{4+}$ with $VO_2^+$have been studied at $25^{\circ}C$ by spectrophotometric method. With$VO_2^+$ in excess, the $[Mo_3O_4(H_2O)_9]^{4+}$ reaction can be expressed as $Mo^{IV}_3+6V^V{\rightleftarrows}3Mo^{IV}+6V^IV}$. Observed rate constants for the reaction are dependent on [$H^+$] and [$VO_2^+$]. Mechanism for the redox of $[Mo_3O_4(H_2O)_9]^{4+}$and $VO_2^+$ is proposed and discussed.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 1998.05a
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• pp.136-137
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• 1998

• Journal of the Korean Electrochemical Society
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• v.9 no.2
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• pp.59-63
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• 2006

The study is coated tin(IV) oxide coated on the titanium substrate electrodes by electrodepositon and dip-coating method and studied about that physical and electrochemical characterization by coating methods. After titanium substrate is etched in HCl, electrodespotion is coated $SnCl_2{\cdot}2H_2O$ in nitrate solution by pulse technique, dip-coating method is also used $SnCl_2{\cdot}2H_2O$ in 1;1V% HCl and coated by dipping and annealing process. tin(IV) oxide coated on titanium substrate electrodes by two coating methods are studied x-ray diffraction (XRD), scanning electron microscopy (SEM) to compare physical characterization of electrode and potential window by cyclic voltammetry (CV) to observe electrochemical characterization.

• Journal of Veterinary Clinics
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• v.9 no.1
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• pp.301-309
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• 1992

The present study was carried out to compare xylazine(2.2mg/kg, IV), xylazine/acepromazine(1.1mg/kg. IV : 0.2mg/kg, IV) and xylazine/diazepam(1.1mg/kg, IV :1.0mg/kg, IV) anesthesia, to determine useful method out of three kinds of anesthesia and tr evaluate this selected method at hypovolemic state. In xylazine, kylazine/acepromazine and kylazine/diazepam anesthesia, the heart rate was increases after administration of atropine until 10minutes after administration of anesthetics and then decreased gradually in all types of anesthesia. The respiratory rate was decreased after administration of anesthetics in all types of anesthesia. The body temperature was rarely changed in xyiazine/acepromazine and xylazine/diazepam anesthesia, but decreased continuously in xylazine anesthesia. In xylazine and kylazine/acepromazine anesthesia the pedal and corneal reflex were not disappeared completely, but reactions to pin pricking were disappeared. In xylazine/diazepam anesthesia their reflex and reactions were disappeared together. The time from head-up to standing was shortest(32.00min) in kylazine/diazepam anesthesia in comparision with xylazine and kylazine/acepromazine anesthesia. In xylazine/diazepam anesthesia, the heart rates in hypovolemic dogs were decreased soon after administration of anesthetics but recovered immediately. The changes in systolic and diastolic blood pressure in hypovolemic dogs revealed similar trends to their changes in normal dogs after administration of anesthetics. It is considered that rylazine/diazepam anesthesia is one of the useful anesthetic methods in healthy dogs and also in hypovolemic dogs.

• Resources Recycling
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• v.30 no.6
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• pp.36-42
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• 2021

Spent lithium-ion batteries are treated by reduction-smelting at high temperatures to recover valuable metals. Solvent extraction and precipitation of the HCl leaching solution of reduction-smelted metallic alloys resulted in a filtrate containing Ni(II) and a small amount of Si(IV). Adsorption and precipitation experiments were conducted to recover pure Ni(II) compounds from the filtrate. Si(IV) was selectively loaded onto polyacrylamide, but this method did not efficiently filter the solution due to an increase in viscosity. The addition of Na₂CO₃ as a precipitant to the filtrate led to the simultaneous precipitation of Ni(II) and Si(IV). However, it was possible to recover nickel oxalate with a purity higher than 99.99% by selectively precipitating Ni(II) with the addition of Na₂C₂O₄ as a precipitant.

• Journal of the Earthquake Engineering Society of Korea
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• v.13 no.6
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• pp.11-25
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• 2009

A method of instrumentally estimating the seismic intensity (MMI) based on Fourier Acceleration Spectrum, which is the so-called 'FAS MMI method' of Sokolov and Wald (2002), was considered for its applicability to Korea. In order to implement the FAS MMI method, the empirical models of mean (m) and standard deviation (${\sigma}$) for Korea were derived for MMI ${\leq}$ IV according to individual seismic intensity by using the site-consistent horizontal FAS of 580 records from 65 isoseismal maps prepared based on the reported MMI of Korea Meteorological Administration. The site-consistent FAS at a site were obtained by correcting the observed FAS for the difference of the site amplification function relative to that of the target site of Class D station (Yun and Suh, 2007) which was evaluated to be a representative site for the generic soil profile of Korea. The FAS m model for MMI ${\leq}$ IV follows the overall linear relation in log space according to seismic intensities, featuring the FAS mean model for MMI = IV similar to that of the global model of Sokolov and Wald (2002). The ${\sigma}$-values of the FAS model are found to be greater than those of the global model for MMI ${\geq}$ V, while significantly lower than those of the global model for MMI = IV.