• 한국산학기술학회논문지
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• 제8권1호
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• pp.143-150
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• 2007

본 연구는 우리나라 서비스화의 특징을 분석하기 위하여 서비스화에 대한 유력한 설명인 수요편향가설 및 Baumol 가설을 우리나라 경험과 비교하였다. 이를 위하여 Baumol의 모형을 확장하여 패널 GMM방식으로 고용함수를 추정하였다. 분석결과를 요약하면 다음과 같다. 첫째, Clark의 수요편향가설을 살펴보기 위하여 1인당 GDP증가와 서비스고용간의 상관관계를 살펴본 결과 서비스화에 있어 소득증가가 절대적인 역할을 수행한다는 Clark의 수요편향가설을 우리나라의 경우에도 확인할 수 있었다. 둘째, 서비스화에 있어서 생산성격차를 강조하는 Baumol의 가설은 도소매, 음식 및 숙박서비스를 제외하고 모든 서비스분류에서 확인할 수 있었다. 즉 제조업과 각 서비스산업의 노동생산성격차가 확대될수록 서비스업의 고용이 증가한다는 사실을 우리나라의 경우에도 확인할 수 있었다.

• 대한안전경영과학회지
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• 제21권2호
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• pp.15-23
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• 2019

Among service industries of knowledge based economic era, the roles of educational service field are becoming more important and standard of educational service makes a direct effect on economic development and social growth. Therefore, accurate measurement of service quality is the most important assignment and the measurement of the service quality remains difficult assignment. So, this researcher classified quality attributes applying weighted value and found potential satisfaction level(PSL) and potential customer demand improvement index(PCDI) for trainees participating in national manpower business so as to suggest measurement of service quality and easiness of use and then, calculated satisfaction position and opportunity cost by quality factor with Taguchi's loss fraction. And, improvable satisfaction level was measured, opportunity cost by degree of customer dissatisfaction was quantitatively measured, and a model that can indicate with economic factors was suggested. In addition, methodology of measuring quality cost that can be reduced by quality improvement and direction of strategic decision-making for deciding items to be improved preferentially were suggested with qualitative index that can indicate the degree of customers' dissatisfaction by loss.

• 대한산업공학회지
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• 제34권4호
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• pp.414-424
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• 2008

Disassembly scheduling is the problem of determining the quantity and timing of disassembling used or end-of-life products while satisfying the demand of their parts or components over a given planning horizon. This paper considers the two-level disassembly structure that describes a direct relationship between the used product and its parts or components. To formulate the problem mathematically, we first suggest an integer programming model, and then reformulate it to a dynamic programming model after characterizing properties of optimal solutions. Based on the dynamic programming model, we develop a polynomial exact algorithm and illustrate it with an example problem.

• 조명전기설비학회논문지
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• 제28권12호
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• pp.18-29
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• 2014

This paper proposes the integration of photovoltaic (PV) and energy storage systems for sustained power generation. In this proposed system, whenever the PV system cannot completely meet load demands, the super capacitor provides power to meet the remaining load. A power management strategy is designed for the proposed system to manage power flows between PV array systems and supercapacitors (SC). The main task of this study was to design PV systems with storage strategies including MPPT with direct control and an advanced DC-link controller and to analyze dynamic model proposed for a PV-SC hybrid power generation system. In this paper, the simulation models for the hybrid energy system are developed using Matlab/Simulink, SimPowerSystems and Matlab/Stateflow tool. This is the key innovative contribution of the research paper. The system performances are verified by carrying out simulation studies using practical load demand profile and real weather data.

• Nuclear Engineering and Technology
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• 제36권2호
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• pp.175-183
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• 2004

For the analysis of a dry process fuel cycle, new modules were implemented into the fuel cycle analysis code DYMOND, which was developed by the Argonne National Laboratory. The modifications were made to the energy demand prediction model, a Canada deuterium uranium (CANDU) reactor, direct use of spent pressurized water reactor (PWR) fuel in CANDU reactors (DUPIC) fuel cycle model, the fuel cycle calculation module, and the input/output modules. The performance of the modified DYMOND code was assessed for the postulated once-through fuel cycle models including both the PWR and CANDU reactor. This paper presents modifications of the DYMOND code and the results of sample calculations for the PWR once-though and DUPIC fuel cycles.

• 농업과학연구
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• 제50권4호
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• pp.629-643
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• 2023

The purpose of this study was to examine the effectiveness and efficiency of a policy by comparing and analyzing the impact of the rice market isolation system and production adjustment system (strategic crops direct payment system that induces the cultivation of other crops instead of rice) on rice supply, rice price, and government's financial expenditure. To achieve this purpose, a rice supply and demand forecasting and policy simulation model was developed in this study using a partial equilibrium model limited to a single item (rice), a dynamic equation model system, and a structural equation system that reflects the casual relationship between variables with economic theory. The rice policy analysis model used a recursive model and not a simultaneous equation model. The policy is distinct from that of previous studies, in which changes in government's policy affected the price of rice during harvest and the lean season before the next harvest, and price changes affected the supply and demand of rice according to the modeling, that is, a more specific policy effect analysis. The analysis showed that the market isolation system increased government's financial expenditure compared to the production adjustment system, suggesting low policy financial efficiency, low policy effectiveness on target, and increased harvest price. In particular, the market isolation system temporarily increased the price during harvest season but decreased the price during the lean season due to an increase in ending stock caused by increased production and government stock. Therefore, a decrease in price during the lean season may decrease annual farm-gate prices, and the reverse seasonal amplitude is expected to intensify.

• International Journal of Railway
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• 제7권1호
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• pp.24-33
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• 2014

The Korean high-speed rail (HSR) began its commercial service in 2004. This service has been created significant changes in the system of intercity passenger travels of Korea. However, the actual ridership was approximately half of the estimated one in the planning stage. In this background, this paper presents the difference between the stated preference (SP) before the HSR service and the revealed preference (RP) after it using the intercity travel mode choice models. Several meaningful differences are found in terms of the factors affecting the travel mode choice, the estimation results of model, the monetary values of time, and elasticities. While the access/egress travel time of high-speed rail is less important than in-vehicle travel time in the SP sample, they have same weight in the RP sample. Also the RP models show that the probability of choosing HSR can be decreased by the increase of the number of vehicles in household contrary to the results from the SP models. The monetary values of travel time are relatively high and the direct and cross elasticities in response to changes in level-of-service of HSR are relatively low in the RP sample. This Korean case is expected to offer referable material for preparing high-speed rail services in other countries by showing the difference between the SP and RP before/after the actual service, identifying the importance of access/egress travel time and lower direct elasticities of HSR demand.

• 대한교통학회지
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• 제34권1호
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• pp.95-106
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• 2016

우리나라 항공 여객수요는 2014년 기준 국제선 5,700만명, 국내선 2,400만명에 도달하였으며, 지속적인 증가 추세를 보일 것으로 예상되고 있다. 이에 따른 국내 공항시설들의 확충 계획이 활발히 진행되고 있으며, 이를 위해 선행적으로 항공수요 예측을 위한 모형 개발이 필요하다. 우리나라에서는 국내총생산을 설명변수로 한 계량경제모형을 주로 항공수요 모형으로 이용하고 있으며, 시계열 자료의 안정성을 고려하지 않을 때 발생하는 허구적 회귀 현상에 대한 많은 논의가 이루어지지 않은 상태이다. 본 연구에서는 시계열 자료의 안정성을 고려한 항공수요 계량경제모형을 개발하였다. 시계열 자료의 특성을 검정하기 위한 단위근 검정과 변수들 간의 장기균형관계를 분석하기 위한 공적분 검정에 대한 이론적 고찰을 수행하였다. 마지막으로, 시계열 자료의 안정성을 고려한 항공수요 계량경제모형 개발 프로세스를 정립하였다. 정립된 프로세스의 적용 가능성을 검증하기 위해 제주공항 국내선 수요를 대상으로 항공수요 모형을 산정하였다. 수요 모형의 설명변수는 국내총생산과 항공요금지수를 이용하였으며, 기존 항공수요 계량경제모형에서 발생하는 문제점을 해소한 것으로 나타났다.

• Structural Engineering and Mechanics
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• 제77권6호
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• pp.705-720
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• 2021

Reinforced concrete (RC) columns are the primary type of vertical support used in building structures that sustain vertical loads. However, their strength may be insufficient due to fire, earthquake or volatile environments. The load demand may be increased due to new functional usages of the structure. The deformability of concrete columns can be greatly reduced under high axial load conditions. In response, a novel steel encasement that distinguishes from the traditional steel jacketing that is assembled by welding or bolt is developed. This novel strengthening method features easy installation and quick strengthening because direct fastening is used to connect the four steel plates surrounding the column. This new connection method is usually used to quickly and stably connect two steel components by driving high strength fastener into the steel components. The connections together with the steel plates behave like transverse reinforcement, which can provide passive confinement to the concrete. The confined column along with the steel plates resist the axial load. By this way, the axial load capacity and deformability of the column can be enhanced. Eight columns are tested to examine the reliability and effectiveness of the proposed method. The effects of the vertical spacing between adjacent connections, thickness of the steel plate and number of fasteners in each connection are studied to identify the critical parameters which affect the load bearing performance and deformation behavior. Lastly, a theoretical model is proposed for predicting the axial load capacity of the strengthened RC columns.

• Industrial Engineering and Management Systems
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• 제4권1호
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• pp.47-53
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• 2005

The efficiency of fabrication (fab) operation is one of the key factors in order for a semiconductor manufacturing company to stay competitive. Optimization of manpower and forecasting manpower needs in a modern fab is an essential part of the future strategic planing and a very important to the operational efficiency. As the semiconductor manufacturing technology has entered the 8-inch wafer era, the complexity of fab operation increases with the increase of wafer size. The wafer handling method has evolved from manual mode in 6-inch wafer fab to semi-automated or fully automated factory in 8-inch and 12-inch wafer fab. The distribution of manpower requirement in each specialty varied as the trend of fab operation goes for downsizing manpower with automation and outsourcing maintenance work. This paper is to study the specialty distribution of manpower from the requirement in a typical 6-inch, 8-inch to 12-inch wafer fab. The human resource planning in today’s fab operation shall consider many factors, which include the stability of technical talents. This empirical study mainly focuses on the human resource planning, the manpower distribution of specialty structure and the forecast model of internal demand/supply in current semiconductor manufacturing company. Considering the market fluctuation with the demand of varied products and the advance in process technology, the study is to design a headcount forecast model based on current manpower planning for direct labour (DL) and indirect labour (IDL) in Taiwan’s fab. The model can be used to forecast the future manpower requirement on each specialty for the strategic planning of human resource to serve the development of the industry.