• Human Ecology Research
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• v.52 no.6
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• pp.617-627
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• 2014

The purpose of this study was to investigate the effects of the instrumental activities of daily living (IADL) and depression on the life satisfaction of the rural elderly. The research subjects of this study were 1,000 people aged 65 years and over living in the rural areas of Korea. The data were collected using a questionnaire with direct interviews and analyzed using SPSS ver. 18.0 for Windows. The results of this study were as follows: First, the rural elderly's depression was affected by the IADL, cost of living, education level, and farming variables. The higher the IADL, the more sufficient the cost of living, the higher the education level and the more the farming time that the rural elderly had, the lower was the level of depression that they had. Second, the life satisfaction of the rural elderly was affected by the cost of living, depression, IADL, need for life services, and gender. The more sufficient the cost of living, the lower the level of depression, the higher the IADL, the less the need for life services, the higher was the life satisfaction that they experienced. Third, the results of the path analysis revealed that life satisfaction was influenced both directly and indirectly. The factors that affected life satisfaction directly were the cost of living, IADL, need for life services, and gender. The factors that affect life satisfaction indirectly were the IADL, cost of living, education level, and farming. Among them, farming and education level influenced life satisfaction indirectly through the parameter variables of depression.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.30 no.3
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• pp.130-142
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• 2018

We use heat pumps with thermal storage system to reduce peak usage of electric power during winters and summers. A heat pump stores thermal energy in a thermal storage tank during the night, to meet load requirements during the day. This system stabilizes the supply and demand of electric power; moreover by utilizing the inexpensive midnight electric power, thus making it cost effective. In this study, we propose a system wherein the thermal storage tank and heat pump are modeled using the TRNSYS, whereas the control simulations are performed by (i) conventional control methods (i.e., thermal storage priority method and heat pump priority method); (ii) region control method, which operates at the optimal part load ratio of the heat pump; (iii) load response control method, which minimizes operating cost responding to load; and (iv) dynamic programming method, which runs the system by following the minimum cost path. We observed that the electricity cost using the region control method, load response control approach, and dynamic programing method was lower compared to using conventional control techniques. According to the annual simulation results, the electricity cost utilizing the load response control method is 43% and 4.4% lower than those obtained by the conventional techniques. We can note that the result related to the power cost was similar to that obtained by the dynamic programming method based on the load prediction. We can, therefore, conclude that the load response control method turned out to be more advantageous when compared to the conventional techniques regarding power consumption and electricity costs.

• Health Policy and Management
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• v.20 no.4
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• pp.45-57
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• 2010

Background : If different cost efficiency indexes were informed to the same clinic depending on the inclusion or exclusion of pharmacy cost, it may impair the reliability of provider-profiling system. This study aimed to investigate whether the omission of pharmacy cost affects cost-efficiency rankings in medical clinics. Methods : Data for ambulatory care cost at 23,112 medical clinics were collected from the claims database, which was constructed after review by the Health Insurance Review and Assessment Service (HIRA) of Korea in April 2007. We calculated two types of cost efficiency indexes by inclusion or exclusion of pharmacy cost for a medical clinic. The agreement between the decile rankings of the two indexes was also assessed using the weighted kappa statistic of Landis and Koch. Results : When the cost efficiency index for total cost including pharmacy cost was compared with the index for total cost excluding it, the agreement between the two indexes was only 55%. The agreements between the two indexes were relatively low within specialties which have larger pharmacy volume of total cost and lower correlation between total cost with or without pharmacy cost included than the average level of all the specialties. Conclusion : These results suggest that the omission of pharmacy cost may result in contradictory outcomes that may be confusing to a medical institution and may impair the reliability of provider-profiling systems. It is very important to standardize profiling criteria for the reliability of provider profiling system.

• Management Science and Financial Engineering
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• v.3 no.1
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• pp.57-74
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• 1997

An EOQ-like inventory model for a manufacturing process is studied. The system is assumed to deteriorate during the production process. The results are either the production of a number of defective items, or the breakdown of the production machine. The optimal production lot size is derived. The model is extended to the case in which the probabilities of making defective items and machine breakdowns are a function of both the quantity (amount) and quality (performance) of the consumed setup cost (including the preventive maintenance cost). We further assume that the setup performance can be improved by investing in the performance improvement program. Hence, the same or a better setup outcome can be achieved with a lower setup cost. We then investigate the optimal setup cost and investment policy simultaneously, thereby achieving a better process quality and setup cost reduction concurrently.

• Journal of the Korean Institute of Navigation
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• v.23 no.3
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• pp.61-73
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• 1999

Capital cost of ships for advanced maritime countries is generally regarded as an international cost, which is, or can be, irrelevant with respect to the nationality of shipowners. However, Korean shipowners have been not only forced by national laws and regulations to build their ships at Korean shipyards, but also restricted to access to foreign financial markets. Having said that, as far as Korean shipowners are concerned, the capital cost has become a national cost. Consequently, it causes them to lower International competitiveness. This paper aims to identify the causes deteriorating international competitiveness of Korean shipping with reference to capital costs and suggest constructive proposals.

• Journal of the Korean Operations Research and Management Science Society
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• v.14 no.2
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• pp.53-66
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• 1989

The Public Vehicle Routing Problem (PVRP) is to find the minimum total cost routes of M or less Public-Vehicles to traverse the required arcs(streets) at least once, and return to their starting depot on a directed network. In this paper, first, a mathematical model is formulated as minimal cost flow model with illegal subtour elimination constraints, and with the fixed cost and routing cost as an objective function. Second, an efficient branch and bound algorithm is developed to obtain an exact solution. A subproblem in this method is a minimal cost flow problem relaxing illegal subtour elimination constraints. The branching strategy is a variable dichotomy method according to the entering nonrequired arcs which are candidates to eneter into an illegal subtour. To accelerate the fathoming process, a tighter lower bound of a candidate subproblem is calculated by using a minimum reduced coast of the entering nonrequired arcs. Computational results based on randomly generated networks report that the developed algorithm is efficient.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.1
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• pp.9-17
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• 1992

Proper resource allocation is also a very important topic in power system problems, especially in operation and planning. One such is optimal maintenance problem in operation and planning. Least cost and highest reliability should be the subjects to be pursued. A probabilistic operation simulation model developed recently by authors is applied to the proboem of optimal maintenance scheduling. Three different methods are compared, marginal maintenance cost, levelized risk and maintenance space. The method by the marginal maintenance costs shows the least cost, the highest reliability and the highest maintenance outage rates. This latter characteristics may considerably influence the results of genetation planning, because the usual maintenance outages obtained from the other methods have shown to be lower.

• Journal of Internet Computing and Services
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• v.5 no.5
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• pp.17-26
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• 2004

Mobile multicast schemes are classified into remote subscription and bi-directional tunneling. While the former scheme has much overhead in the maintenances of multicast tree, the latter suffers from inefficient routing. In this paper, we propose dynamic mobile multicast routing (DMMR) scheme, which is operated on the basis of cost functions related with forwarding cost and tree reconstruction cost, Basically DMMR intends to find lower cost between forwarding cost and tree reconstruction cost. Forwarding cost is the cost of tunneling multicast packets from home agent, and tree reconstruction cost is the joining cost of foreign agent to multicast group. In the case that a mobile host moves to the other area, its foreign agent calculates cost functions related with forwarding cost and tree reconstruction cost. If forwarding cost is higher than tree reconstruction cost, foreign agent joins to multicast group and reconstructs the multicast tree. Accordingly, foreign agent can dynamically adapt remote subscription or bi-directional tunneling, Our scheme provides more stable multicast service to the mobile hosts regardless of the movements of mobile host and the number of mobile group members.

• Asian-Australasian Journal of Animal Sciences
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• v.9 no.4
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• pp.411-420
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• 1996

Asia Triple HIn this study an attempt was made to determine the cost of producing fodders at Savar Dairy Farm (SDF). For this purpose, all seasonal fodders, such as Maize, Jowar, Cowpea and Oat and all perennial fodders, such as Para and Napier were studied. The highest acreage of land was allocated to high-land Para (33.8%) and the lowest acreage (2.7%) was devoted to Cowpea. Jowar attained the highest yield (74.2 tons) per hectare and Maize attained the lowest yield (25.8 tons/h). The highest cost per hectare was attributed to Jowar (TK. 20944.18) while the lowest cost was attributed to low-land para (TK. 10349.86). The cost of production of fodder per kilogram was the highest (TK. 0.66) for Maize and the lowest for Oat (TK. 0.24). The cost of production of low-land Para was much lower than that of high land Para. The per kilogram cost of silage production was the highest (TK. 0.71) for Maize and the lowest (TK. 0.31) was for Napier. The gross return analysis further showed that the highest net margin and B:C ratio were observed for Napier followed by Low-land Para, Jowar, Oat, Cowpea, High-land Para and Maize. Therefore, those fodders whose B:C ratios and yield/ha were higher should be allocated more area of land to stimulate increased returns to SDF in the future is suggested.

• Journal of the Korea Safety Management & Science
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• v.16 no.1
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• pp.239-250
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• 2014

The purpose of this research is to implement and develop the Economic Cost Driver Size(ECDS) extended model to determine the optimal cash driver size with measurement complexity cost and allocation fail cost. ECDS model can be used to seek both measurement accuracy and time efficiency of the Activity-Base Costing (ABC). The study also develops Activity Priority Number (APN) to evaluate the importance of nonvalue-added activities improvement and to determine the representative cost driver of value-added activities when applying ECDS model. APN consists of Severity Priority Number (SPN), Undetectablitiy Priority Number (UPN) and Occurrence Priority Number (OPN). APN can be obtained from lower-stream activity, current activity, upper-stream activity in terms of hierarchical dependency of SIPOC (Supplier, Input, Process, Output, and Customer). In order to seek both efficiency of invested capital and reduction of overhead cost, the paper proposes the integrated ABC and Economic Value Added (EVA) model using redesigned ABC-based statement of comprehensive income and EVA-based statement of financial position. For a better understanding of the proposed ABC-EVA integrated model, numerical examples are demonstrated in this paper. Cost drivers of ABC and capital drivers of EVA in the proposed model can be used to reduce activity overhead cost from ABC-based statement of comprehensive income and to lessen activity capital charge from EVA-based statement of financial position.