• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.589-594
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• 1991

Group Technology (GT) is a technique for identifying and bringing together related or similar components in a production process in order to take advantage of their similarities by making use of, for example, the inherent economies of flow production methods. The process of identification, from large variety and total of components, of the part families requiring similar manufacturing operations and forming the associated groups of machines is referred as 'machine-component grouping'. First part of this paper is devoted to describing a hierarchical divisive algorithm based on graph theory to find the natural part families. The objective is to form components into part families such that the degree of inter-relations is high among components within the same part family and low between components of different part families. Second part of this paper focuses on establishing cell design procedures. The aim is to create cells in which the most expensive and important machines-called key machine - have a reasonably high utilization and the machines should be allocated to minimize the intercell movement of machine loads. To fulfil the above objectives, 0-1 integer programming model is developed and the solution procedures are found. Next an attempt is made to test the feasibility of the proposed method. Several different problems appearing in the literature are chosen and the results air briefly showed.

• Steel and Composite Structures
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• 제4권3호
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• pp.189-209
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• 2004

The commonly used seismic design procedures to evaluate the maximum effect of both horizontal components of earthquakes, namely, the Square Root of the Sum of the Squares (SRSS) and the 30-percent (30%) combination rules, are re-evaluated. The maximum seismic responses of four three-dimensional moment resisting steel frames, in terms of the total base shear and the axial loads at interior, lateral and corner columns, are estimated as realistically as possible by simultaneously applying both horizontal components. Then, the abovementioned combination rules and others are evaluated. The numerical study indicates that both, the SRSS rule and the 30% combination method, may underestimate the combined effect. It is observed that the underestimation is more for the SRSS than for the 30% rule. In addition, the underestimation is more for inelastic analysis than for elastic analysis. The underestimation cannot be correlated with the height of the frames or the predominant period of the earthquakes. A basic probabilistic study is performed in order to estimate the accuracy of the 30% rule in the evaluation of the combined effect. Based on the results obtained in this study, it is concluded that the design requirements for the combined effect of the horizontal components, as outlined in some code-specified seismic design procedures, need to be modified. New combination ways are suggested.

• 정보처리학회논문지D
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• 제14D권4호
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• pp.389-394
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• 2007

본 연구는 자바와 C++ 컴포넌트로부터 동적으로 웹 서비스를 생성하기 위한 연구로써, 온톨로지를 이용하여 시맨틱 웹 서비스를 지원하고자 한다. 시맨틱 웹 서비스는 웹의 내용뿐 만 아니라 웹 서비스의 접근을 용이하게 하는 장점이 있다. 이를 위해 컴포넌트를 위한 시맨틱 서비스 발견이 필요하며, 컴포넌트로부터 웹서비스를 생성하기 위해 온톨로지 기반 프레임워크를 활용한다. 특히, 본 연구에서는 컴포넌트와 온톨로지를 UML 모델로 변환시키고, 이를 다시 WSDL 문서로 사상시키므로써, 객체 모델링를 이용한 동적 웹 서비스 생성을 한다. 본 연구의 주요 의의는 컴포넌트로부터 웹서비스를 동적으로 생성하는 것과 온톨로지를 사용하므로써, 시맨틱 웹 환경을 제공하는 것이다. 다시 말해, 본 연구 는 온톨로지 기반 시맨틱 웹 서비스와 CBD 방법론을 통합하고자 한다.

• 한국분말재료학회지
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• 제19권4호
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• pp.264-270
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• 2012

In this study, we mainly focus on the study of densification of gas-atomized Cu-50 wt.%In-13 wt.%Ga alloy powder without occurrence of crack during the forming process. Cu-50 wt.%In-13 wt.%Ga alloy powder was consolidated by sintering and rolling processes in order to obtain high density. The phase and microstructure of formed materials were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM) and optical microscopy (OM), respectively. Warm rolling using copper can result in the improvement of density. The specimen obtained with 80% of rolling reduction ratio at $140^{\circ}C$ using cooper can have the highest density of $8.039g/cm^3$.

• 한국대기환경학회지
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• 제11권4호
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• pp.331-337
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• 1995

This study was carried out to investigate the chemical composition of dustfall at Cheju(mean sea level; 71.7m, 33$^{\circ}$17'N, 126$^{\circ}$10'E) and Ullung island(mean sea level; 22.1m, 38$^{\circ}$29'N, 130$^{\circ}$54'E) from October 1993 to september 1994. The dustfall matter samples were collected by deposit gauges. The ionic components of each samples was analyzed by Ion Chromatograpy (Dionex 4000i), While heavy metals by Inductively Coupled Plasma Atomic Emission Spectrometry(ICP/AES; Shimadzu ICP-4). The results for seasonal variation of dustfall matter matter total amount, water-soluble ionic components and water-soluble ionic components total deposition amount to two sites were compared each other. The seasonal variations of dustfall amount at Ullung and Cheju island were found in order of Spring>Winter>Fall>Summer, and the maximum of dustfall amount were during the Yellow Sand period. Also, Total amount of water-soluble components except for $F^{[-10]}$ were high in Cheju more than Ullung island.more than Ullung island.

• ETRI Journal
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• 제38권6호
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• pp.1179-1189
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• 2016

A chemorheological analysis of a no-flow underfill was conducted using curing kinetics through isothermal and dynamic differential scanning calorimetry, viscosity measurement, and solder (Sn/27In/54Bi, melting temperature of $86^{\circ}C$) wetting observations. The analysis used an epoxy system with an anhydride curing agent and carboxyl fluxing capability to remove oxide on the surface of a metal filler. A curing kinetic of the no-flow underfill with a processing temperature of $130^{\circ}C$ was successfully completed using phenomenological models such as autocatalytic and nth-order models. Temperature-dependent kinetic parameters were identified within a temperature range of $125^{\circ}C$ to $135^{\circ}C$. The phenomenon of solder wetting was visually observed using an optical microscope, and the conversion and viscosity at the moment of solder wetting were quantitatively investigated. It is expected that the curing kinetics and rheological property of a no-flow underfill can be adopted in arbitrary processing applications.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2862-2867
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• 2008

High-temperature components of gas turbine operated for certain period of time can be reused by being repaired or rejuvenated. In case of the gas turbine combustion liners, the biggest and the most important one in the high-temperature components, come in a repair shop after operated for 8,000 or 12,000 hours according to the model and go through the repair and rejuvenation in order to be reused. A stated combustion liner is the first channel which has the combustion gas reached a nozzle from a fuel nozzle. Materials and coating properties of old and new model combustion liners were investigated. To repair these components after the visual inspection, the coatings of combustion liners were removed and then FPI(Fluorescent Penetrant Inspection), a kind of the NDI(Non-Destructive Inspection), was conducted. Damage patterns and the number of the damaged components were classified and analyzed based on data provided from the visual inspection over a long period of time. Focusing on the difference between old model and new model combustion liners, we analyzed the damage distribution and changes and consequently concluded that new model combustion liner would increase repair rate.

• Earthquakes and Structures
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• 제16권5호
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• pp.575-588
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• 2019

Seismic design method based on bearing capacity has been widely adopted in building codes around the world, however, damage and collapse state of structure under strong earthquake can not be reflected accurately. This paper aims to present a deformation-based seismic design method based on the research of RC component deformation index limit, which combines with the feature of Chinese building codes. In the proposed method, building performance is divided into five levels and components are classified into three types according to their importance. Five specific design approaches, namely, "Elastic Design", "Unyielding Design", "Limit Design", "Minimum Section Design" and "Deformation Assessment", are defined and used in different scenarios to prove whether the seismic performance objectives are attained. For the components which exhibit ductile failure, deformation of components under strong earthquake are obtained quantitatively in order to identify the damage state of the components. For the components which present brittle shear failure, their performance is guaranteed by bearing capacity. As a case study, seismic design of an extremely irregular twin-tower high rise building was carried out according to the proposed method. The results evidenced that the damage and anti-collapse ability of structure were estimated and controlled by both deformation and bearing capacity.

• 한국지구과학회지
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• 제39권4호
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• pp.388-400
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• 2018

The purpose of this study was to explore the nine components of computational thinking (CT) practices and their operational definitions from the view of science education and to develop a CT practice framework that is going to be used as a planning and assessing tool for CT practice, as it is required for students to equip with in order to become creative problem solvers in $21^{st}$ century. We employed this framework into the earlier developed STEAM programs to see how it was valid and reliable. We first reviewed theoretical articles about CT from computer science and technology education field. We then proposed 9 components of CT as defined in technology education but modified operational definitions in each component from the perspective of science education. This preliminary CTPF (computational thinking practice framework) from the viewpoint of science education consisting of 9 components including data collection, data analysis, data representation, decomposing, abstraction, algorithm and procedures, automation, simulation, and parallelization. We discussed each component with operational definition to check if those components were useful in and applicable for science programs. We employed this CTPF into two different topics of STEAM programs to see if those components were observable with operational definitions. The profile of CT components within the selected STEAM programs for this study showed one sequential spectrum covering from data collection to simulation as the grade level went higher. The first three data related CT components were dominating at elementary level, all components of CT except parallelization were found at middle school level, and finally more frequencies in every component of CT except parallelization were also found at high school level than middle school level. On the basis of the result of CT usage in STEAM programs, we included 'generalization' in CTPF of science education instead of 'parallelization' which was not found. The implication about teacher education was made based on the CTPF in terms of science education.

• 품질경영학회지
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• 제39권3호
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• pp.400-411
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• 2011

Process variables are factors in an experiment that are not mixture components but could affect the blending properties of the mixture ingredients. For example, the effectiveness of an etching solution which is measured as an etch rate is not only a function of the proportions of the three acids that are combined to form the mixture, but also depends on the temperature of the solution and the agitation rate. Efficient designs for the mixture components-process variables experiments depend on the mixture components-process variables model which is called a combined model. We often use the product model between the canonical polynomial model for the mixture and process variables model as a combined model. In this paper we propose three starting models for the mixture components-process variables experiments. One of the starting model we are considering is the model which includes product terms up to cubic order interactions between mixture effects and the linear & pure quadratic effect of the process variables from the product model. In this paper, we propose a method for finding robust designs and practical designs with respect to D-, G-, and I-optimality for the various starting combined models and then, we find practically efficient and robust designs for estimating the regression coefficients for those models. We find the prediction capability of those recommended designs in the case of three components and three process variables to be good by checking FDS(Fraction of Design Space) plots.