• 전기학회논문지P
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• 제64권4호
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• pp.297-302
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• 2015

Replacing a manual switch installed in a feeder for a distribution system with an automatic one increases the reliability of the electric power system. This is because the automatic switch can shorten the duration of a fault the customer experiences by splitting the faulty section faster than the manual one does. However, improving the reliability of the distribution system may increase investment costs. Here, the investment costs include automatic switch cost, replacement work cost and labor cost. For this reason, importance should be attached to the proper balance between the increase of the investment costs and the improvement of the reliability of the distribution system. This article analyzed reliability index and economics when manual switches installed in a feeder (RBTS Bus2 model) was replaced by automatic ones. In addition, it attempted to draw the optimum rate of automation of manual switches by automatic ones using the GRG optimization method, considering the current economic requirements.

• Environmental Engineering Research
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• 제21권2호
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• pp.132-139
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• 2016

In early 90s the worldwide awareness about the energy crisis and global warming had been increased and emission reduction (by improving energy efficiency), as well as increasing the capacity of clean and renewable energies, showed themselves as the most important steps towards the sustainable development approach. However, investigations on Iran's environmental situation show huge decline in recent decades and apparently there is no sense of urgency about these issues through the vision of Iranian politicians. In this article the idea of replacing the old gas turbines of Polkalleh natural gas compressor station - as one of the main compressor stations of Iran - with newer and more efficient gas turbines is evaluated, emphatically for reducing greenhouse gases emissions and their environmental costs and decreasing natural gas consumption as well. Clearly such idea is costly, but analyzing its economic impacts, huge declines in annual costs and greenhouse gases emissions can be seen as well. So an investment about $95 million can decrease 40% of Polkalleh compressor station annual costs, 25% of natural consumption and 30% of $CO_2$ and $NO_x$ emissions. Besides the simple payback period of this investment is about 2.5 years from the cut-expenses of annual costs.

• 지식경영연구
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• 제9권4호
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• pp.113-125
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• 2008

Net present value (NPV) and return on investment (ROI) are commonly used to evaluate investment in new technologies. Sometimes, however, measuring the value of investment in new IT becomes very difficult due to its wide scope of application coupled with embedded options in its adoption. Therefore, comprehensive but easily understandable methodologies are needed to solve the complicated problems resulting from the complexity of new technologies. This paper employs a real option analysis to evaluate RFID adoption in the supply chain. Real options analysis should be a better way to evaluate a disruptive technology like RFID. However, the pure (probabilistic) real option rule characterizes the present value of expected cash flows and the expected costs by a single number, which is not realistic in many cases. To solve the problem, this paper considers the real option rule in a more realistic setting, namely, when the present values of expected cash flows and expected costs are estimated by trapezoidal fuzzy numbers.

• 설비공학논문집
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• 제24권9호
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• pp.657-662
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• 2012

The cogeneration system can operate at efficiencies greater than those achieved when heat and power are produced in separate. The optimal system can be determined by selecting the auxiliary system combined with cogeneration system. In the present study, economic investigation has been conducted with the cogeneration electric heat pump(EHP) system and the cogeneration absorption chiller(AC) system to install in a school dormitory. To analyze life cycle cost(LCC), cost items such as initial investment costs, annual energy costs and maintenance costs of each system have been considered. The initial investment cost is referred to the basis of estimated costs, and annual energy costs such as the electric power and gas consumption are based on the data in a school dormitory. LCC is evaluated with the present worth method. Considering investigated results, the initial investment cost of the cogeneration EHP system is more profitable about 24% than that of the cogeneration AC system. The energy cost of the cogeneration EHP system is more profitable about 8% than the cogeneration AC system. The LCC shows that the cogeneration EHP system is the most effective system in the school dormitory.

• Transactions on Electrical and Electronic Materials
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• 제18권2호
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• pp.111-118
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• 2017

The increased diversity of different types of energy sources requires moving towards smart distribution networks. This paper proposes a probabilistic DG (distributed generation) units planning model to determine technology type, capacity and location of DG units while simultaneously allocating ESS (energy storage systems) based on pre-determined capacities. This problem is studied in a wind integrated power system considering loads, prices and wind power generation uncertainties. A suitable method for DG unit planning will reduce costs and improve reliability concerns. Objective function is a cost function that minimizes DG investment and operational cost, purchased energy costs from upstream networks, the defined cost to reliability index, energy losses and the investment and degradation costs of ESS. Electrical load is a time variable and the model simulates a typical radial network successfully. The proposed model was solved using the DICOPT solver under GAMS optimization software.

• 품질경영학회지
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• 제31권4호
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• pp.1-18
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• 2003

Quality is a critical competitive factor in today's environment because of the impact of quality on costs and delivery. Many companies regard quality as a key concept of company strategy in order to achieve the competitive edge. Measuring and reporting quality cost is the first step in quality management program. The supposition of quality cost model is that investment in prevention activities will bring rewards from reduced failure costs, and that further investment in prevention activities will show profits from reduced appraisal costs. In this study, the degree of quality cost deviation is conceptualized. This means a deviation between the ideal and present ranking in the amounts of quality cost categories. This study analysed that the effect of its deviation on quality management activity and performance variables. However, there are no difference in these variables. The major reason is that most of companies are endeavoring for quality management but operating quality cost system unsystematically. The review against a prevention and appraisal activity is necessary.

• ETRI Journal
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• 제28권6호
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• pp.777-786
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• 2006

Since the introduction of competition in the telecommunication market due to the growth of the interconnection between heterogeneous networks, particularly fixed and mobile networks, the interconnection charge based on traffic-sensitive (TS) and non-traffic-sensitive (NTS) costs has become more important. Although there have been many studies of the public switched telephone network (PSTN), previous studies of TS and NTS costs in mobile networks are very few. In this paper, as a pilot study, we propose three criteria and a procedure for the classification of TS and NTS costs based on mobile systems. The three criteria are the following: function type, investment requirement, and main exhaust driver. Moreover, for a CDMA mobile system, strongly TS, strongly NTS, and mixed components are classified by the proposed criteria and procedure. The proposed criteria, procedure, and classification can provide a systematic and useful guideline to decide the scope of mobile facilities and to determine the terminating cost on mobile networks from fixed networks.

• 한국시스템다이내믹스연구
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• 제12권1호
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• pp.75-87
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• 2011

Congestion problems can be approached from the viewpoint of system dynamics theory. The relationship between road capacity and congestion can be explained by the 'relative control' archetype among four system archetypes suggested by Wolstenholme. There is a balancing feedback loop between road capacity and road congestion. However, there is another balancing loop between road congestion and car traffic volume, which keeps disrupting the equilibrium of the former loop. A system dynamics model, which is based on a partial adjustment model of induced traffic in the literature, is built to simulate three road building scenarios: 'Expanding investment', 'Balancing investment' and 'Frozen road investment' scenarios. The 'Expanding investment' scenario manages to drop congestion levels by 9% over 30 years, however, causing much higher emissions of $CO_2$ than other scenarios. The trade-off relationship between congestion levels and environmental costs must be taken into consideration for road investment policies.

• 경영정보학연구
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• 제8권1호
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• pp.265-285
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• 2006

본 연구는 IT프로젝트 사전타당성 평가항목을 도출하고, 각 평가항목의 가중치를 AHP 기법에 의하여 산출하였으며, 3개 IT프로젝트 유형에 따른 평가항목별 가중치 차이를 통계적으로 검증하였다. 국내 민간기업 및 공공조직에서 제안된 79개 IT프로젝트에 대한 AHP 조사에서 7개 평가항목의 가중치는 재무적 효과 25.14%, 전략적 가치 22.34%, 직접비용 14.44%, 리스크 12.05%, 기술적 필요성 11.50%, 정치적 고려 8.26%, 간접비용 6.41%로 나타났다. 예상대로 재무적 효과, 전략적 가치, 직접비용의 가중치가 높게 나타난 반면, 최근의 TCO 모델이나 이론적 연구에서 중시되고 있는 간접비용이 실무현장에서는 그다지 중요하게 고려되지 않는 것으로 나타났다. 특히 대부분 신규 IT투자에서 실질적으로 가장 민감하게 영향을 미치고 있다고 간주되는 CEO 관심, 현업부서장의 추진의지 등과 같은 정치적 고려항목이 낮게 나타난 것은 의외의 현상이며, 그 원인에 대한 체계적 분석을 향후 연구과제로 제안한다. 그리고 ANOVA 분석 결과 거래처리형, 정보제공형, 인프라형 3개 프로젝트 유형별로 평가항목 가중치가 다른 것으로 분석되었다.

• 환경정책연구
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• 제14권4호
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• pp.63-101
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• 2015

배출권 이월 및 차입은 감축기술개발투자에 영향을 미칠 수 있다. 배출권거래제하에서 이월 및 차입이 허용되면 감축비용과 배출권 가격에 따라 배출권거래제 참여기업들은 현재의 감축을 미래로 또는 미래의 감축을 현재로 선택할 수 있기 때문에 배출권 이월 및 차입은 감축기술개발에 대한 대체재적인 역할을 한다. 따라서 배출권 이월 및 차입과 같은 간접감축이행수단을 허용하는 경우에는 직접감축이행수단인 감축기술개발투자에 영향을 미친다. 불완전경쟁시장에서 이러한 간접감축조치가 감축기술개발투자에 미치는 영향은 완전경쟁시장하에서와 달라질 수 있다. 왜냐하면 과점시장의 쿠르노 경쟁하에서 감축기술개발투자가 최종소비재시장의 균형에 영향을 미칠 수 있기 때문이다. 분석 결과, 배출권 이월 및 차입으로 인한 감축기술개발투자 유인 수준은 감축비용, 할인계수, 초기무상할당, 감축기술개발투자효과 등에 의존한다.