• 산업공학
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• 제23권4호
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• pp.319-326
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• 2010

The SMB supercomputing service provides a supercomputing infrastructure for Small and Medium-sized Business (SMB) to enhance the efficiency of product development activity. In this study, the economic value of SMB supercomputing service is presented. The economic value of service is comprised of a direct and an indirect economic value. A direct economic value was estimated based on the result of user survey on service effectiveness. The input-output analysis method was adopted to estimate an indirect economic value induced from a direct economic value. The future economic value based on the result of user demand survey is also presented. As a result, the annual and future economic value of service were estimated about 55,215 million won and 323,928 million won, respectively.

• Journal of Electrical Engineering and Technology
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• 제13권4호
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• pp.1549-1557
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• 2018

Optimizing the design of large-scale electric machines based on nonlinear finite element analysis (FEA) requires longer computation time than other applications of FEA, mainly due to the huge size of the machines. This paper addresses a new region decision method (RDM) with mesh adaptive direct search (MADS) for the optimal design of wind generators in order to reduce the computation time. The validity of the proposed algorithm is evaluated using Rastrigin and Goldstein-Price benchmark function. Moreover, the algorithm is employed for the optimal design of a 5.6MW interior permanent magnet synchronous generator to minimize the torque ripple. Additionally, mechanical stress analysis as well as electromagnetic field analysis have been implemented to prevent breakdown caused by large centrifugal forces of the modified design.

• Nuclear Engineering and Technology
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• 제54권8호
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• pp.3130-3139
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• 2022

Direct containment heating (DCH) is one of the potential factors leading to early containment failure. DCH is closely related to safety analysis and containment performance evaluation of nuclear power plants. In this study, a DCH prediction program was developed to analyze the DCH loads of containment vessel. The phenomenological model of debris dispersal, metal oxidation reaction, debris-atmospheric heat transfer and hydrogen jet burn was established. Code assessment was performed by comparing with several separate effect tests and integral effect tests. The comparison between the predicted results and experimental data shows that the program can predict the key parameters such as peak pressure, temperature, and hydrogen production in containment well, and for most comparisons the relative errors can be maintained within 20%. Among them, the prediction uncertainty of hydrogen production is slightly larger. The analysis shows that the main sources of the error are the difference of time scale and the oxidation of cavity debris.

• 한국분무공학회지
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• 제29권1호
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• pp.7-15
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• 2024

This study investigates the performance of 2.0L hybrid vehicles equipped with Liquefied Petroleum Gas (LPG) fuel engines, using energy flow analysis. By incorporating a direct LPG injection system (LPDi), the research aims to overcome the reduced maximum output commonly associated with LPG engines. Moreover, the integration of a hybrid system is explored as a means to enhance vehicle fuel economy while reducing CO₂ and emissions. The study employs data from FTP-75 and HWFET driving cycle to inform future research efforts focused on predicting CO₂ emissions and fuel economy for Hybrid Electric Vehicles utilizing LPG Direct Injection. The findings offer insights into optimizing fuel systems for better environmental and operational performance in hybrid vehicles.

• 한국재료학회지
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• 제28권6호
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• pp.330-336
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• 2018

In this study, a membrane electrode assembly(MEA) composed of three electrodes(anode, cathode, and reference electrode) is designed to investigate the effects of methanol concentration on the overpotentials of anode and cathode in direct methanol fuel cells(DMFCs). Using the three-electrode cell, in-situ analyses of the overpotentials are carried out during direct methanol fuel cell operation. It is demonstrated that the three-electrode cell can work effectively in transient state operating condition as well as in steady-state condition, and the anode and cathode exhibit different overpotential curves depending on the concentration of methanol used as fuel. Therefore, from the real-time separation of the anode and cathode overpotentials, it is possible to more clearly prove the methanol crossover effect, and it is expected that in-situ analysis using the three-electrode cell will provide an opportunity to obtain more diverse results in the area of fuel cell research.

• The Journal of Asian Finance, Economics and Business
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• 제6권4호
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• pp.109-114
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• 2019

The purpose of the study to evaluate the contribution of foreign direct investment (FDI) and tourism receipts (TR) to Sri Lanka's gross domestic product (GDP). This study employs time series annual data for the period from 1978 to 2016 and EViews 10 econometrics software was used for the time series data analysis. Unit root test was done on the variables and the method chosen was the Augmented Dicky - Fuller test. Co-integration analysis was used for the long run relationship and the Granger causality test was performed to investigate the causal relationship. Recently a more conducive environment has been established after the three decade long ethnic war came to an end. In this context, the Sri Lankan government has taken positive measures to attract foreign direct investment and boost tourism in the country. This study intends to evaluate the contribution of Sri Lanka, as these two factors are considered to be very effective at increasing the GDP of a country. The empirical study shows that there is a positive and statistically significant relationship between the variable's TR and FDI to the GDP in the long run. Results of Granger causality test implied that the two-way causality promoted the economic growth of Sri Lanka.

• 통상정보연구
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• 제12권3호
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• pp.223-242
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• 2010

Since the reopening of official relations in 1992, Korean and China have become major trading partners, apart from myriad exchanges in culture and other aspects of society. The subject of this study is to analysis on determinants for China market entry type of the Korean company. This article measure the effects on Korea exporter interests of Korea's trade with china. This paper investigates the determinants of export and FDI referring in entry type in the China's market of Korea company. There are 250 samples and 130 returns, 170 of them are analyzed for a entry competitiveness. This paper has there main a parts, Multiple regression result shows that the export entry competitiveness are positively affected by the product character and market character. However, The enterprise character and location character does not affect in the export competitiveness. Also, the direct investment entry competitiveness are positively affected by the market character and location character. However, The enterprise character and product character does not affect in the direct investment. Logit analysis result show that the direct investment entry does positively affected in CEO international mind and export entry does affect in more than rival competitive products. In addition, the export entry does positively affected in the customer taste diversity, political risk and economical risk, market environment instability.

• Human Ecology Research
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• 제52권3호
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• pp.213-228
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• 2014

This study examined the effects of peer relationships, depression, and aggression on bullying and victimization among boys and girls. The subjects were 364 3rd grade students (boys, 218; girls, 146) and 368 6th grade students (boys, 186; girls, 182), that is, a total of 732 students from three elementary schools. Data were collected on bullying, victimization, peer relationships (mutual friendship, mutual antipathy, and peer popularity), depression, and aggression (overt aggression and relationship aggression) from July 12, 2012 to July 13, 2012. These data were analyzed by means of a chi-squared analysis, t-test, and a logistic regression analysis. The results revealed that there were differences by sex in the case of direct bullying and victimization but no differences in the case of indirect bullying and victimization. Among boys, the factors influencing direct bullying were depression and overt aggression, and the factor influencing direct/indirect victimization was depression. Among girls, the factors influencing direct bullying were mutual antipathy relations and relational aggression, the factors influencing indirect victimization were mutual antipathy relations and peer popularity, the factor influencing indirect bullying was mutual antipathy relations, and the factor influencing indirect victimization was peer popularity. The results of this study showed that the factors influencing bullying and victimization are differences in sex. Finally, the implications and methodology for developing bullying prevention education programs were discussed.

• Structural Engineering and Mechanics
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• 제54권4호
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• pp.793-807
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• 2015

Constructing the influence lines of forces of statically indeterminate structures is a traditional issue in structural engineering and mechanics. However, the existing kinematic method for establishing these force influence lines is an indirect or mixed approach by combining the force method with the theorem of reciprocal displacements, which is yet inconsistent with the kinematic method for statically determinate structure. This paper proposes the direct kinematic method in conjunction with the load-displacement differential relation for exactly constructing influence lines of reaction and internal forces of indeterminate structures. Firstly, through applying the principle of virtual displacement, the formula for influence lines of reaction and internal forces of indeterminate structure via direct kinematic method is derived based on the released structure. Then, a computational approach with a clear concept and unified procedure as well as wide applicability based on the load-displacement differential relation of beam is suggested to achieve conveniently the closed-form expression of force influence lines, and exactly draw them. Finally, three representative examples for constructing force influence lines of statically indeterminate beams and frame illustrate the superiority of the proposed method.

• 한국융합학회논문지
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• 제9권3호
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• pp.223-230
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• 2018

본 연구는 국방연구개발사업의 자료를 통하여 사업 수행 간 원가가 변동되는 양상을 분석하였다. 2가지 형태의 모형을 활용한 실증분석을 통하여 원가변동(개산원가 대비 정산원가)에 영향을 미치는 원가비목과 그 영향력을 확인하였다. 모형1(17개 원가 비목)을 활용한 검증 결과, 17개 원가 비목 중 감가상각비, 관세 등 4개 원가 비목을 제외하고 정산원가 차액과 상관관계를 가지는 것을 확인하였다. 대표적으로 직접노무비의 영향력은 1.022이고 외주가공비의 영향력은 0.942로 확인되었다. "직접노무비 중심의 원가 계산"을 고려한 모형2(직접비)를 이용한 검증 결과, 모든 직접 원가 비목이 정산원가 차액과 상관관계를 가지는 것을 확인하였다. 대표적으로 직접노무비의 영향력은 2.014이고 외주가공비의 영향력은 1.068로 확인되었다. 이 연구의 결과를 통해 "직접노무비 중심의 원가계산"을 실증분석 하였고, 외주가공비를 활용한 원가 절감 유인 또한 발견하였다.