• 대한안전경영과학회지
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• 제18권3호
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• pp.71-80
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• 2016

This study is on safety improvement measures through analysis of accident cases during plant storage tank construction. Storage tank is a general term for artificial ground facility constructed to store oil, water, gas, and other chemicals. Some companies have clustered storage tanks (tank farm). The construction methods vary according to the component and types of fluids. Because most of the construction procedures include lifting heavy weight materials using heavy construction equipment and are carried out at high places, storage tank construction contains more risk factors than normal aerial construction. Recently, major accidents such as storage tank collapse have occurred often, and cost many lives due to the characteristics of the structure. In this study we would like to analyze the cause of these accidents and propose measures to improve safety.

• 한국컴퓨터정보학회논문지
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• 제21권8호
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• pp.65-75
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• 2016

In this paper, we present a novel approach to help MSR researchers obtain necessary data with a tool, termed General Purpose Extractor for Source code (GPES). GPES has a single function extracts high-quality data, e.g., the version history, abstract syntax tree (AST), changed code diff, and software quality metrics. Moreover, features such as an AST of other languages or new software metrics can be extended easily given that GPES has a flexible data model and a component-based design. We conducted several case studies to evaluate the usefulness and effectiveness of our tool. Case studies show that researchers can reduce the overall cost of data analysis by transforming the data into the required formats.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부A
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• pp.37-39
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• 1998

The hybrid step motor has found applications in a wide range of mechanical systems as a low cost, open-loop positioning device. The step motor provides good stiffness at rest against disturbing load influences, a combination of moderate speed fine resolution, high reliability and simplicity. In recent years, considerable competition has arisen over the technological issue of wheather the device should be applied as a 2-Phase or 5-Phase machine. In this paper, to compare two systems, we have atempted to derive the mathematical. model, and analysed operating detent torque with this model. The analysis shows that a fundamental component of the permeance distribution produces the average torque and that harmonic components produce the ripple torque.

• Nuclear Engineering and Technology
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• 제8권2호
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• pp.101-116
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• 1976

고리 1호기 및 2호기 원자로의 발전단가에 대한 해석을 시도했다. 해석의 편의상 발전단가를 우선 건설, 운전 및 관리, 운전자금 및 핵연로 등에 관련된 비용성분으로 나누고, 이 중 첫 세성분에 대한 cost는 POWERCO-50 계산코오드를, 그리고 핵연료 비는 MITCOST-II를 써서 계산했다. 중요한 계산결과로서는 다른 세가지 핵연료 주기에 대한 고리 2획의 핵연료 주기비, 고리 1호 및 2호기의 발전단가 및 발전단가계산에 사용된 코스트 자료의 변화에 따른 발전단가의 민감도 등이다. 제래식 화력발전단가와 비교함으로써 원자력발전이 보다 경제적으로 유리하다는 사실을 알아내었지만 고리 2 호기의 건설비가 다른 PWR 발전에 비해 다소 고가임을 지적했다. 때문에 원자력발전을 유리하게 하기 위해서는 장차 도입될 원자력발전로의 경우 고리 2호기와 같은 turnkey 계약이 지양되어야 함을 지적했다. 또한 발전단가가 발전소 가동율의 변화에 따라 민감하게 변동한다는 사실로부터 발전소를 최대한 가동시킬 수 있도록 노력이 경주되어야 한다고 결론을 내렸다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 추계학술대회 논문집
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• pp.188-191
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• 2007

This paper shows the Development of In-tank pressure regulator and Solenoid Valve used in FCV(Fuel Cell Vehicle). We have developed new type of Regulator and Solenoid through analysis of the structure and characteristics of component of FCS(Fuel Cell System) from the advanced technology. Now it is possible to localize the component by making use of the development of Regulator and Solenoid made by us. Regulator and Solenoid is a equipment to control hydrogen pressure supplied into a stack. Therefore, outlet pressure, a flow of fluid and temperature are important parameters according to a inlet pressure. And leak test, endurance test and burst test should be done to guarantee the performance and safety of Regulator and Solenoid used in the fuel of high pressure. Also, Hydrogen friendly materials are applied to inner parts of the Regulator, Solenoid and weight reduction is done to cost saving in part not related to performance. As a result, we have proven the good performance and reliability in endurance of Regulator, Solenoid and will make an development in performance as well as durability to ensure industrialization.

• 한국기계가공학회지
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• 제19권7호
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• pp.1-6
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• 2020

Micro-structure components applied to various disciplines are steadily demanded with lighter weight and better quality. This is because that ultra thin-wall injection molding has been paid attention with a lot of benefits such as cost reduction, shorter process period, and so forth. However, this technology is complicate and difficult to obtain high quality of products compared with conventional injection molding due to warpage caused by uneven shrinkage and molecular orientation. Since warpage of products directly affects product quality and overall performance of devices, it is essential to predict deformation behavior to achieve high precision of molded products. Therefore, this study aims to find out adequate thin-wall mold design for FPC connector housing by employing Moldflow simulation before application. In addition, experimental research is performed by using a fabricated mold structure based on simulated results to prove accuracy and reliability of the suggested simulation for warpage analysis.

• Geomechanics and Engineering
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• 제14권1호
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• pp.91-98
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• 2018

Length of a vehicle is an important variation to generate different variants of an automotive platform. This parameter is usually adjusted by embedding dimensional flexibility into different components of the Body in White (BIW) including the floor pan. Due to future uncertainties, it is not necessarily possible to define certain values of wheelbase for the future products of a platform. This work is performed to add flexibility into the design process of a length-variable floor pan. By means of this analysis, the cost and time consuming process of optimization is not necessary to be performed for designing the different variants of a product family. Stiffness and mass of the floor pan are two important functional requirements of this component which directly affect the occupant comfort, dynamic characteristics, fuel economy and environmental protection of the vehicle. A combination of Genetic algorithm, GMDH-type of artificial neural networks and TOPSIS methods is used to optimally design the floor pan associated with arbitrary length of the variant in the defined system range. The correlation between the optimal results shows that for a constant mass of the floor pan, the first natural frequency decreases by increasing the length of this component.

• 대한가정학회지
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• 제30권1호
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• pp.149-161
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• 1992

The purpose of this study is to analyze information search activity in purchasing behavior of household electric goods. Qusetionare survey method was used in this research. The sample was taken from 302 housewives living in Seoul, from 9th of Nov. to 20th of Nov, in 1991. Used statical methods were Frequency, Percentage, Crosstab, Anova, and Regression Analysis. The major findings are summarized as follows : 1) Component elements of information search : The means of acquiring information is that friends, neighbors, sales are most. A cause of choosing information is the sequence of satisfaction after using, easiness of interaction. The time in choosing goods is more month. 2) Component element of information search as social economic status housewife : children numbers and means of acquiring information(P<.01), education and a cause of choosing information(P<.05), life cost per month and a cause of choosing information(P<.05), social economic status and a time information search are significant. 3) A perception of risk as searching information : Among searching content of information a price influence a perception of risk. 4) Content of searching information and satisfaction of purchasing experience : Best choice is significant as quality of goods, difference of quality is significant as safety and degree of offering information is significant as a brand. 5) Satisfaction of purchasing experience following practical use of information : Best choice is significant as viewing of an exhibit and opinion of user. Difference of quality is not significant as any vairable. Degree of offer information influence searching pamphlet, searching an advertisement and opinion of user. 6) A perception of risk following source of an information : A perception of risk is most influenced by pamphlet.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.1649-1651
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• 2000

Optical properties of $Cd_{1-x}Zn_{x}S$ films deposited by :chemical bath deposition(CBD), which is a very attractive method for low-cost and large-area solar cells, are presented, Especially, in order to control more effectively the zinc component of the films, zinc acetate, which used as the zinc source, mixed in reaction solution after preheating and the pH of the reaction solution decreased with increasing the concentration of zinc acetate. The films prepared after preheating and pH control had larger zinc component and higher optical band gap. As the more zinc substituted for Cd in the films, the optical transmittance improved, while the absorption edge shifts to a shorter wavelength and the optical band gap increased. The photo conductivity of the films was larger than the dark conductivity, while the ratio of those increased with increasing the mole ratio of zinc acetate.

• 한국자동차공학회논문집
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• 제11권4호
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• pp.58-67
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• 2003

An automotive engine cooling system is closely related with overall engine performances, such as reduction of fuel consumption, decrease of air pollution, and increase of engine life. Because of complex reaction between each component, the direct experiment, using a vehicle, takes high cost, long time, and slow response to the system change. Therefore, a computer simulation would provide the designer with an inexpensive and effective tool for design, development, and optimization of the engine cooling system over a wide range of operating conditions. In this work, it has been predicted the thermal performance of the engine cooling system in cases of stationary mode, constant speed mode, and city-drive mode by mathematical modelling of each component and numerical analysis. The components are engine, radiator, heater, thermostat, water pump, and cooling fans. Since the engine model is the most important, that is divided into eight sub-sections. The volume mean temperature of eight sub-sections are simultaneously calculated at a time. For detail calculation, the radiator and heater are also divided into many sub-sections like control volumes in finite difference method. Each sub-section is assumed to consist of three parts, coolant, tube with fin, and air. Hence it has been developed the simulation program that can be used in case of design and system configuration changes. The overall performance results obtained by the program were desirable and the time-traced tendencies of the results agreed fairly well with those of actual situations.