• Journal of the Korean Operations Research and Management Science Society
• /
• v.31 no.3
• /
• pp.27-40
• /
• 2006

Today's customer demands in supply chains tend to change quickly, variously even in a short time Interval. The uncertainties of customer demands make it difficult for supply chains to achieve efficient inventory replenishment, resulting in loosing sales opportunity or keeping excessive chain wide inventories. Un this paper, we propose an adaptive vendor managed inventory (VMI) model for a two-echelon supply chain with non-stationary customer demands using the action-reward learning method. The Purpose of this model is to decrease the inventory cost adaptively. The control Parameter, a compensation factor, is designed to adaptively change as customer demand pattern changes. A simulation-based experiment was performed to compare the performance of the adaptive VMI model.

• Journal of the Korean Institute of Navigation
• /
• v.23 no.2
• /
• pp.11-22
• /
• 1999

This paper is concerned with the development of a tractable model to assist liner shipping companies in the decision-making of empty container repositioning and leasing. A hybrid methodology is presented which properly accounts for the specific characteristics of empty container management. For this mathematical models are developed based on dynamic network models, covering both land and marine segment. Then a stochastic method is presented to deal with the uncertainty of the future demand and supply. Especially, the concept of opportunity cost has been introduced in order to explain interactions between the variation of the future demand and supply and the stock level at each depot.

• Journal of Families and Better Life
• /
• v.17 no.2
• /
• pp.19-30
• /
• 1999

The measurement of women's unpaid work is one of the important issues for the improvement of women's status and establishment of a women policy. The purpose of this study is to measure of household production of housewife and to estimate the ratio to GDP. And to emphasize the political meaning of housework The results are as follow; 1) The monetary value of housework of one housewife in 1995 was 783,050won by opportunity cost method . 2) The ratio of household production to GDP 1995 was approximately 16.5%.

• Environmental and Resource Economics Review
• /
• v.30 no.1
• /
• pp.107-128
• /
• 2021

It has been recognized that implementing the marginal price mechanism to CBP is not acceptable due to the lack of revenue of the marginal generators. This study shows that it is not the problem of marginal price mechanism but the structural problems originated by the suspension of restructuring, the technical limits of RSC program and inaccuracy of the generation cost estimation method. This study explains the method to calculate the cost function in operating modes of the CC generators and proposes the modeling for the CC generators in RSC program. To implementing the cost function in operating modes could give an opportunity to change the price setting mechanism from average to marginal cost. The price setting mechanism based on the marginal cost will be one of the main points to provide the right price signals and to introduce a real-time and A/S markets to prepare the energy transition era.

• Journal of the Korean Home Economics Association
• /
• v.31 no.4
• /
• pp.37-51
• /
• 1993

The Objects of this study are: 1. To compare the housework time of housewives by region and employment status. 2. To compare the economic value of housework by region and employment status. 3. To evaluate the economic value of housework by each method. The subjects of this study were 815 housewives living in Taegu and Kyungsangpookdo. The statistics used for data analysis were frequency, percentile, T-test, ANOVA and Seheffe test by SPSS PC programs: 1) The average housework time was 7.8hours per day. Full-time housewives spent 8.2hours and employed housewives spent 6.7hours to housework. 2) Partially there were significant difference in economic value of housework by employment status. 3) Estimates of economic value of housework by each method of evaluation are : (unit : won) sample mean method monthly (1) Specialized substitute method 587,080 (2) Overall substitute method 760,640 (3) Opportunity cost method 556,060 (4) Reservation wage method 534,070 (5) Subjective evalution method 644,540

• Journal of Information Technology Services
• /
• v.5 no.1
• /
• pp.47-59
• /
• 2006

According to the policy for "e-Korea construction" of Korean government, Investment of information system during the past decade are dramatically increasing. More than a half of this investment is cost of hardware infrastructure. So, accurate hardware sizing are essential for higher efficiency of investment. Accurate hardware sizing benefits are generally viewed in terms of the avoidance of excess equipment and lost opportunity costs by not being able to support business needs. Unfortunately, however, little research effort to make the hardware sizing methodology are doing. We propose a sizing method for information system in public sector. This method is determinate empirical study that are gathering and analyzing cases, making method and reviewing expert. Finally we are proposed calculating method for hardware components that is CPU, memory, internal and external disk according to the application system type which is OLTP, Web, WAS. Our study certainly will act as a catalyst for higher investment-efficiency of the future information programs in public sector.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2003.05a
• /
• pp.620-627
• /
• 2003

The real option pricing theory has emerged as the new investment decision-making techniques superceding the traditional discounted cash flow techniques and thus has greatly received muck attention from academics and practitioners in these days the theory has been widely applied to a variety of corporate strategic projects such as a new drug R&D, an internet start-up. an advanced manufacturing system. and so on A lot of people who are interested in the real option pricing theory complain that it is difficult to understand the true meaning of the real option value. though. One of the most conspicuous reasons for the complaint may be due to the fact that there exit many different ways to calculate the real options value in this paper, we will present a replicating portfolio method. a risk-neutral probability method. a risk-adjusted discount rate method (quasi capital asset pricing method). and an opportunity cost concept-based method under the conditions of a binomial lattice option pricing theory.

• Proceedings of the KSME Conference
• /
• 2000.11b
• /
• pp.216-221
• /
• 2000

Most Ice making companies make simple efforts to make products and fail to introduce improvements into the system against huh cost of products. The work presented here is an implementation of ice making method to improve both energy efficiency and productivity. In this present investigation, several ice making cycles are designed and calculated to evaluate COP, ice making time and electric energy consumption. Results obtained shows that COP is improved with more efficient use of time for ice making and electric consumption. Therefore this can offer the opportunity for more efficient energy consumption and productivity in ice making.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.13 no.6
• /
• pp.455-461
• /
• 2001

Domestic ice making companies make effort to obtain products and neglect to introduce low cost product improvements with energy savings. The work presented here is an implementation of ice making method to improve both energy efficiency and productivity. In this present investigation, several ice making cycles are proposed for higher efficiency in the system. COP(Coefficient of Performance), ice making time and electric energy consumption are evaluated and compared with the conventional system. Results shows that COP is improved with more efficient use of time for ice making and electric consumption. Therefore, this can offer an opportunity for more efficient use of energy and higher productivity in ice making.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.11 no.17
• /
• pp.39-46
• /
• 1988

This Paper is concerned with a man-multi machine assignment problem to minimize idle time. Assuming different types of semi-automatic machines with deterministic service-processing time, the problem approaches by sequential dependent one operator can handle several machines, where determine optimal range the cost of idle labor and machine time is to be minimized in preparing a work schedule. The Procedure, to establish man-machine assignment model, and it's results are: (1) Objective function to minimize opportunity loss cost, which is happened by idle time, is verified recursive process through heuristic method. (2) The algorithm, is programmed by BASIC language for personal computer, and a numerical example is given to illustrate the heuristic algorithm. This study will be helpful to enhance productivity of Shopflooras a result of increasing the efficiencies of both operator and machine.