• 경영과학
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• 제31권3호
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• pp.95-111
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• 2014

It is essential to carry out an economic analysis on public water supply projects so that policy makers and water enterprises are aware of the actual value of the project. However, many popular approaches based on discounted cash flow analysis do not capture the uncertainties inherent in cash flow. In order to analyze the economic values of the water supply project of local governments, we utilize real option model, which considers uncertainty in future water price behavior and captures the value of real life flexibility. The real option model is designed to incorporate the option to expand and abandon, and it is applied to a local government case. Furthermore, we assess the project by exploring Luehrman's option space to accommodate the more efficient decision making. The results show that substantial amount of potential value is included in the public water supply service, and the overall value is greater than the value obtained from the discounted cash flow model.

• 한국의류학회지
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• 제29권1호
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• pp.79-90
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• 2005

The purpose of this study is to find out the wearing conditions and cause of discomfort with shoes for male college students which will provide useful information fur the shoes manufacturer. The questionnaire survey was conducted on 346 male college students on purchasing practices, wearing conditions, and overall satisfaction with shoes. The results were as follows: Male college students have a tendency to have longer buying cycles and buy more expensive shoes compare to high school students. The order of criteria considered fer purchasing was shape, price, style coordination with clothing. The order of criteria considered for purchasing differed according to their major, economic status and purchasing place. Most of them have two pairs of white or black sports shoes and one pair of either black or brown dress shoes. The most popular material was man made leather but college students have more leather shoes than high school students. There were differences between high school students and college students in wearing conditions, how many they have, material and color. The varieties of shoes differed by season. They were satisfied with their shoes' design and color but unsatisfied with qualify or the material and durability of the shoes. Due to the pressure of the shoes, they experienced discomfort such as numbness, blisters on the feet and red skin. They experienced discomfort on the soles of the feet. The causes of discomfort were shape, width, hight of the heel, material and length in order. Dress shoes cause more discomfort than sport shoes due to the hardness of material, and flexibility of the sole. Since the material differed by the price, the degree of discomfort significantly differed by price too.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.695-699
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• 2003

It is general to use the control network in control systems in order to reduce the complexity of the related wiring harnesses and to improve the system flexibility. CAN becomes one of the most popular network protocols because of its low price, multiple sources, high performance and reliability. This paper describes a CAN based real-time control of the fire detection system for the intelligent building system. The proposed fire detection and alarm system is stronger than the previous one against noises and communication media faults and can solve many problems such as complex cabling and increment of I/O ports by using many sensors. Furthermore, MMI can be achieved easily with the personal computer that is used for replacing the traditional monitoring system. The proposed system is implemented and the experimental results are given.

• 경영과학
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• 제18권1호
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• pp.29-39
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• 2001

Traditionally, companies have been concerned with making an investment decision either to go now or never to go forever. However, owing to the development of the theory of options pricing in a financial investment field and its introduction to the appraisal of real investments in these days, we are now partially allowed to derive the value of a managerial flexibility of real investment projects. In this paper, we derived a general mathematical model to price the option value of real investment projects assuming that they have only one-period of time under which uncertainty exists. This mathematical model was developed based on the opportunity cost concept. We will show a simple numerical example to illustrate how the mathematical model works comparing it with the existing models.

• 경영과학
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• 제19권2호
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• pp.125-137
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• 2002

The telecommunications market is expanding rapidly and becoming more substitutive. In this environment, demand forecasting is very difficult, yet important for both practitioners and researchers. in this paper, we adopt the modeling approach proposed dy Jun and Park ［6］. The basic premise is that demand patterns result from choice behavior, where customers choose a product to maximize their utility. We apply a choice-based substitutive diffusion model to the Korean mobile telecommunication service market where digital service has completely replaced analog service. In comparison with Bass-type multigeneration models. our model provides superior fitting and forecasting performance. The choice-based model is useful in that it enables the description of such complicated environments and provides the flexibility to include marketing mix variables such as price and advertising in the regression analysis.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2008년도 한국우주과학회보 제17권2호
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• pp.29.1-29.1
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• 2008

The temperature control system which is using liquid and gaseous nitrogen has been known as the most economical system to simulate space temperature condition due to relatively not expansive price of the liquid nitrogen (less than 0.2 USD per liter). And, among these systems, the closed loop system which circulates compressed nitrogen gas come from sprayed liquid nitrogen by blower and makes a target temperature with heat from an electrical heater and flow rate of liquid nitrogen is prevail all over the world. But, this complete closed loop system requires expansive equipments such as blower, heater, and liquid nitrogen injector, and special maintenance on the system. Therefore, KARI is developing efficient and simple open loop system which utilizes liquid and gaseous nitrogen with eliminating a special blower and other expansive units. In this study, this open loop system with more efficiency and flexibility will be designed and introduced.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 A
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• pp.369-372
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• 2000

An overview on applications of wavelet transform in power systems presented in this paper. Wavelet transform is capable of making trade-offs between time and frequency resolutions, which is a property that makes it appropriate for the analysis of non stationary signal. In recent years, wavelet transform is widely accepted as a technology offering an alternative way due to its flexibility in representation of non-stationary signal even in power systems. This paper presents various applications of wavelet transform in power systems. Wavelet transform has been used by the authors in the field of power system protection for the classification of transient signals, and forecasting of short term loads and system marginal price and so on. Various research works carried out by many researchers in power systems are summarized.

• 응용통계연구
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• 제24권5호
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• pp.759-768
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• 2011

Tree algorithms have been widely developed for regression problems. One of the good features of a regression tree is the flexibility of fitting because it can correctly capture the nonlinearity of data well. Especially, data with sudden structural breaks such as the price of oil and exchange rates could be fitted well with a simple mixture of a few piecewise linear regression models. Now that split points are determined by chi-squared statistics related with residuals from fitting piecewise linear models and the split variable is chosen by an objective criterion, we can get a quite reasonable fitting result which goes in line with the visual interpretation of data. The piecewise linear regression by a regression tree can be used as a good fitting method, and can be applied to a dataset with much fluctuation.

• 대한안전경영과학회지
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• 제3권3호
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• pp.165-174
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• 2001

Internet is a global network and it produces many terminologies involved in Electronic Commerce. Among many terms people very much talked about Cyber Shopping Mall. Under situation customers and sellers paid attention to Cyber Shopping Mall which is beyond time and space. This study deals with two subjects to enlarge the competitive power of Mall & Malls which is integration of multiple Cyber Shopping Mall. First subject is constructing the Automated Mall Wizard which is efficiently and effectively building Cyber Shopping Mall Site. And second subject is to differentiate from other shopping malls. Automated Mall Wizard is composed of three stages which are decomposed into several descriptive steps. And descriptive steps takes form of independent module, so it is considered to maximize Cyber Shopping Mall differentiation. Additional functions are making the goods category, related goods to be simultaneously ordered, price comparison with other sites within the Mall & Malls, best seller goods, store advertisement, substitutive goods, and mileage policy. As a result of that, we can respect SuperMall is better than other Mall & Mall as to diversity and flexibility of constructed Cyber Shopping Mall.

• 한국경영과학회지
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• 제21권2호
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• pp.171-186
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• 1996

This paper comes from an observation that overemphasis on capacity utilization meausre, which is usual under capacity shortage, can seriously hurt the firm's profit and potential process improvement. We suggest a model that can be used in designing a coordination scheme for decentralized marketing and manufacturing activities. Using a price and time-sensitive demand and capacitated lotsizing model, we derive an effective communication medium betwen marketing and manufacturing. This Balance Indicator of process capacity and flexibility also implies that the increase in capacity availability and setup time reduction should be balanced by its market requirements. This is particularly important when a firm tries to improve its process capability by kaizen. Further, the model can be used to show the comparative performances of scheduling policies under capacity imbalnce. We show the shortening the scheduling cycle can improve the firm profit without changing the simple scheduling rule.