• Journal of KIISE
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• v.44 no.8
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• pp.854-859
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• 2017

Caching popular videos in the storage of base stations is an efficient method to reduce the transmission latency. This paper proposes an incentive proactive cache mechanism in the wireless network to motivate the content providers (CPs) to participate in the caching procedure. The system consists of one/many Infrastructure Provider (InP) and many CPs. The InP aims to define the price it charges the CPs to maximize its revenue while the CPs compete to determine the number of files they cache at the InP's base stations (BSs). We conceive this system within the framework of Stackelberg game where InP is considered as the leader and CPs are the followers. By using backward induction, we show closed form of the amount of cache space that each CP renting on each base station and then solve the optimization problem to calculate the price that InP leases each CP. This is different from the existing works in that we consider the non-uniform pricing scheme. The numerical results show that InP's profit in the proposed scheme is higher than in the uniform pricing.

• Journal of the Korean Geographical Society
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• v.48 no.2
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• pp.272-287
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• 2013

This paper describes the importance of selecting explanatory variables(e.g. land price determinants) in hedonic pricing models employed in predicting real estate price, and explores dynamics of the land price determinants over time. The City of Junju was chosen as the study area, and repeated measured price data of standard lots over 17 years were analyzed. We applied a three-level modeling approach to this data in consideration of its nested data structure and longitudinal characteristics. Main land price determinants we focused on are primarily based on items included in the standard comparison table of land price, which is an official hedonic pricing model used by Government to estimate land price for tax levy. Our result shows that the land price fluctuation over 17 years was not uniform over the whole study area with each neighborhood revealing different price trend, and as such warrants longitudinal model components. In addition, some of determinants previously recognized as important were proved insignificant. It was also found that significant determinants at a particular time point lost its power gradually over time and vice versa. It is expected that more accurate prediction of price would be possible when taken account for this dynamics of price determinants over time in applying hedonic pricing model method.

• 한국연소학회:학술대회논문집
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• 2014.11a
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• pp.297-299
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• 2014

Petroleum coke has high heating value and low price. Due to the steadily increasing demand for heavy oil processing, the production volume of petroleum coke tends to be expanded. The high availability and low price of petroleum coke have been strongly considered as candidate fuel for power generation facilities. However the high carbon content, high sulfur content and nitrogen content of petroleum fuel are known to produce relatively large quantity of CO2, high NOx and SO2 emission. In this work, a series of numerical simulations have been carried out in order to investigate the effects of swirl flow intensity on combustion furnace, which is most important operating condition. Results show that the temperature distribution was spatially uniform at about 1600K but high temperature region are located quite differently depending on swirl number. In addition, numerical temperature data was compared with experimental temperature data and its temperature difference shows less than 10%. On the other hand, discrepancy between numerical and experimental emission data were slightly large with necessities of improved emission model.

• Journal of the Semiconductor & Display Technology
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• v.22 no.1
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• pp.33-38
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• 2023

As the demand for large flexible displays such as tablet computers continues to rise, there is an increasing need for cost-efficient colorless and optically transparent polyimide film that can meet the desired performance, particularly optical transmittance. In this study, we investigated a detailed procedure for achieving optimal optical transmittance using two different combinations of monomers: 6FDA+BAPB and 6FDA+BPA+TFDB. We employed a design of experiment method to systematically synthesize polymers, allowing for the optimization of optical transmittance. In addition, we were able to achieve uniform thickness in the films by using a doctor blade. By comparing the price and optical transmittance of four different monomer combinations, we obtained fundamental data on the production of polyimide films that can be customized to meet the specific price and performance requirements of manufacturers. This approach enables users to select the most suitable polyimide film based on their desired price and performance parameters while achieving optimal optical transmittance.

• KIEE International Transactions on Power Engineering
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• v.5A no.1
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• pp.85-92
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• 2005

In this paper, Nash equilibriums of generation markets are investigated using a game theory application for simplified competitive electricity markets. We analyze the characteristics of equilibrium states in N-company spot markets modeled by uniform pricing auctions and propose a new method for obtaining Nash equilibriums of the auction. We assume that spot markets are operated as uniform pricing auctions and that each generation company submits its bids into the auction in the form of a seal-bid. Depending on the bids of generation companies, market demands are allocated to each company accordingly. The uniform pricing auction in this analysis can be formulated as a non-cooperative and static game in which generation companies correspond to players of the game. The coefficient of the bidding function of company-n is the strategy of player-n (company-n) and the payoff of player-n is defined as its profit from the uniform price auction. The solution of this game can be obtained using the concept of the non-cooperative equilibrium originating from the Nash idea. Based on the so called residual demand curve, we can derive the best response function of each generation company in the uniform pricing auction with N companies, analytically. Finally, we present an efficient means to obtain all the possible equilibrium set pairs and to examine their feasibilities as Nash equilibriums. A simple numerical example with three generation companies is demonstrated to illustrate the basic idea of the proposed methodology. From this, we can see the applicability of the proposed method to the real-world problem, even though further future analysis is required.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2002.11a
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• pp.263-268
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• 2002

This paper aimes to analyse the housing market of Ulsan, that changed for Metroplolitan city in 1997. For the housing policy we need sufficient informations on the housing market appeared during the last five years. As a result, we can describe its housing market in a uniform way: Ulsan, compared with other cities, doesn't show varieties in households, housing type, housing conditions etc.. Concerning the housing preference, the results of our survey also show the uniformity. And the price of apartment in Ulsan moves relatively slowly to other cities.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.84.1-84.1
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• 2010

Currently, new and renewable energy come into the spotlight, such as solar energy, wind power, fuel cell, hybrid car etc., due to the energy resource is being depleted. Especially, in order to solve like this problem, the study of solar cell manufacturing systems are being extensively researched such as vacuum process. But the major fault of the vacuum process are its expensive production price. On the order hand, Roll-to-roll printing system, the new technology of solar cell manufacturing, has low production price compare with the vacuum process. Also roll-to-roll printing system can decrease the 95% of waste water and 99.9% of harmful gasses than the vacuum process. So we addressed the roll to roll printing system for the flexible solar cell by using printing technology. This roll-to-roll printing system is comprised of various modules, such as web handling module, fine pattern printing module, dry/curing module, uniform coating module and laminating module etc.

• Korean Journal of Poultry Science
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• v.25 no.2
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• pp.91-98
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• 1998

In order to compare economics of soybean meals (SBMS) imported from Brazil and the U.S., a feeding trial was conducted with 480 commercial broiler chicks (Abor Acres strain) for 38 days. The Brazilian SBM was brownish in color and the protein solubility in 0.2 % KOH solution was 63. 4 %. The U.S. SBM, on the other hand, was a dehulled SBM, and uniform in color (light yellow) and particle size. The protein solubility value of the latter was 76.6 %. Two dietary protein levels (19 % and 21 %) were used for each source of SBM (2x2 factorial). Chicks fed diets containing the U.S. SBM grew significantly faster (P<0.05) and utilized feed more efficiently than chicks fed diets containing Brazilian SBM. Chicks fed diets containing 21 % CP showed better growth performance and profitability than those fed the 19 % CP diets. The price of the U.S. SBM was higher but the feed cost per unit gain was lower than the Brazilian SBM. Results suggest that there are over-cooked SBMs being traded on the Korean rnarket, and attention should be given to not only the price but also the quality of SBMs.

• International conference on construction engineering and project management
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• 2007.03a
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• pp.711-720
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• 2007

Apartment housing in the Korean domestic construction industry has had various and high-quality finishing work since the enforcement of price deregulation in 1998. Before the enforcement of price deregulation, feasibility studies of housing projects have not had particular difficulties as uniform description of finishing work items were reflected and finishing work cost also was equalized. However, the recent distinction of finishing work based on the same floor plan brings about project cost variation, along with many effects on construction management due to project cost increment. Accordingly, this paper suggests the improved plan of cost management to control the feasibility study result consistently during the life cycle of a project through an analysis based on cost management phase due to cost blackout, appearing at the commencement of a project, cost gradation caused by high-quality finishing work item, and cost reduction due to the degradation of finishing work after analysis of current apartment construction process focused on finishing work using the IDEF process analysis technique.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.58
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• pp.149-177
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• 2013

This article introduces and briefly examines the Uniform Rules for Forfaiting (URF)(ICC Publication No. 800), which were prepared by a joint project of the Banking Commission of the International Chamber of Commerce (ICC) and the International Forfaiting Association (IFA), and became effective on January 1, 2013. Forfaiting is a kind of trade financing technic performed by way of a sale and purchase of payment claim between its seller and its buyer, the forfaiter, on a without recourse basis. URF is designed to facilitate global trade finance and embraces all the international payment instruments which are currently used and will be newly developed in the future. URF is expected to be a set of standardized terms and conditions for both the primary and secondary forfaiting markets. In this context, this article first looks into the concept of the forfaiting and certain features and structure of forfaiting transactions. Then this article moves to discussing URF itself. For this it examines (i) the nature and scope of URF and some important definitions provided in URF, (ii) some provisions of URF that apply to the delivery of documents to the forfaiter, the examination, and the acceptance or refusal, of such documents by the forfaiter, and (iii) the payment of purchase price by the forfaiter to its seller, including the matter of "payment under reserve" and repurchase by the seller from the forfaiter. Finally, this article examines liabilities of the parties concerned, before conclusion.