• Asia pacific journal of information systems
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• v.17 no.4
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• pp.97-112
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• 2007

Most traditional newspaper publishers provide online editions to counter the competition of online news providers. However, the relationship between the online and print editions of the same newspaper has not been clearly defined. Some see the online newspaper as a substitute, while others consider it a complement. A 2002 NAA online newspaper consumer survey indicated that one-third of its respondents said they were now using the print newspaper less. Others have argued that the online edition will not wipe out print consumption, and may even complement it. While the print edition offers particular advantages such as portability, less eye strain, and the tactile experience of a printed page, the online edition also offers specific advantages such as access to breaking news, continually updated information, access to old archives, etc. All these factors would tend to lower the degree of interchangeability between the products. However, recent empirical studies show that the online edition is a substitute for rather than a complement of the print edition. Still, to some print readers, the online edition provides additional value. In this paper, by capturing the two different aspects of online editions the substitute aspect and the additional value added aspect as well as other available online alternatives, we develop an analytical model to derive the optimal production and distribution strategies of both online and print editions. Confronting the "free versus fee" issue, we show that it is optimal to provide an online version of the print newspaper for free to non-print subscribers. However, the amount of free news content that the publishers need to put on the Web depends on the available alternatives on the online market. The "fee" and "free" options both have merits and demerits as well. If the publisher charges for the online version of the print newspaper, she can generate revenue from the fee charged to online readers. However, doing so will limit the size of the online audience and further reduce online advertising revenue. At the same time, by providing a high-quality online version and charging for it, the price of the print newspaper must stay low in order to lure high valued readers. On the contrary, if the publisher provides an online version of the print newspaper for free, she can obtain a larger audience for the online version. At the same time, by providing a low-quality online newspaper, the publisher can increase the print newspaper price to get more revenue from high valued offline readers, although no revenue is incoming from online version readers. Through systematic measuring of all the pros and cons, our analysis shows that the optimal option is not "fee" but "free."

• Journal of Korean Society of Transportation
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• v.18 no.2
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• pp.91-101
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• 2000

The optimal congestion charge in transportation economics corresponds to the solution to the welfare maximization Problem for users of a certain road link where congestion takes Place. This congestion charge is in nature the optimal Price of the transportation facility, which is derived by the Partial equilibrium analysis on that facility. Therefore it is not certain that this congestion charge can maximize the well-being of all the users of the total transportation network, since the analysis does not count the impact of the congestion charge on traffic volumes of other links. This study suggests an alternative approach to estimate the optimal congestion charge. The key difference of this study from Previous ones is to derive the solution through the general equilibrium analysis on a market where several transportation facilities as well as Private goods are available to consumers. This approach shows a set of solutions a little different from the Previous one, which are explained below. The optimal congestion charge is derived for two different cases. One is the situation of which the congestion charge is levied on every transportation facility In this case, the optimal solution of each facility should equate the marginal utility of every user to the marginal cost of the corresponding facility. This analysis result in general equilibrium coincides with the Previous analysis result in partial equilibrium. However this result cannot apply to another case of which the charge is imposed only on a certain transportation facility. In this case, the optimal charge on a certain transportation facility should be less than the optimal congestion charge of partial equilibrium analysis.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.210-210
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• 2012

Gas barrier coating from dense thin film deposition has been one of the important applications such as food-packaging and organic display. Especially for food-packaging, plastic container has been widely used due to its low price and high through-put in mass production. However, the plastic container with low surface energy like polypropylene (PP) has been limited to apply gas barrier coating. That is because a gas barrier coating could not adhere to PP due to its too low surface energy and high porosity of PP. In this research, we applied carbon coating consisting of Si and O as an interlayer between silicon oxide (SiOx) and PP. A carbon layer was found to provide better adhesion, which was experimentally proved by oxygen transmission rate (OTR) and SEM images. However, we also found that there is a limitation in the maximum thickness of a carbon layer and SiOx film due to their high stress level. For this conflict, we obtain the optimal thickness of a carbon layer and SiOx film showing optimal gas barrier property.

• Asian Journal of Atmospheric Environment
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• v.10 no.4
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• pp.190-196
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• 2016

The objective of this study is to obtain the optimal conditions to remove hydrogen fluoride (HF) generated from a variety of F-gas treatment processes. First, we selected $Ca(OH)_2$ and $CaCO_3$ as a reactant among the various alkali salts which have a high removal efficiency and a competitive price by forming a calcium fluoride precipitate. Additionally, various factors were investigated to improve the removal efficiency of HF. The conditions such as the settling time, agitating time and intensity, reaction temperature, and pH were considered as main factors. As a result, in the treatment process to remove HF through Ca-based alkali salts, the optimal conditions were a 120 min settling time, 30 min of agitation at 100 rpm, a pH of 4-8, and a reaction temperature of $40^{\circ}C$.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.467-471
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• 2009

A road is a fundammental public traffic facility for transporting people and goods. Road designer should determine the best route considering various conditions to minimize environmental bad effect due to road construction and show road functions sufficiently. In this research, we tried to select the optimal route location by comparing candidate routes considering weights of various items such as land use, slope, aspect, land price and so forth. The candidate routes were analyzed and visualized from built data using a GIS software and then compared with the existing route.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.2
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• pp.254-261
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• 1999

An optimal design code for centrifugal pumps has been developed to determine geometric and fluid dynamic variables under appropriate design constraints. The optimization problem has been formulated with a nonlinear objective function to minimize one, two or all of the fluid dynamic losses, the net positive suction head required and the product price of a pump stage depending on the weighting factors selected as the design compromise. The optimal solution Is obtained by means of the Hooke and Jeeves direct search method. The performance analysis Is based on the mean streamline analysis using the present state-of-the-art loss correlations. The optimized efficiency and design variables of centrifugal pumps are presented in this paper as a function of non-dimensional specific speed in the range, $0.5{\leq}N$, ${\leq}1.3$. The diagrams presented herein can be used efficiently in the preliminary design phase of centrifugal pumps.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.1
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• pp.16-22
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• 2016

This paper addresses the load usage scheduling in the HEMS for residential power consumers. The HEMS would lead the residential users to change their power usage, so as to minimize the cost in response to external information such as a time-varying electricity price, the outside temperature. However, there may be a consumer's inconvenience in the change of the power usage. In order to improve this, it is required to understand the pattern of load usage according to the external information. Therefore, this paper suggests a methodology to model the load usage pattern, which classifies home appliances according to external information affecting the load usage and models the usage pattern for each appliance based on a copula function representing the correlation between variables. The modeled pattern would be reflected as a constraint condition for an optimal load usage scheduling problem in HEMS. To explain an application of the methodology, a case study is performed on an electrical water heater (EWH) and an optimal load usage scheduling for EHW is performed based on the branch-and-bound method. From the case study, it is shown that the load usage pattern can contribute to an efficient power consumption.

• Transactions on Electrical and Electronic Materials
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• v.18 no.6
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• pp.350-358
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• 2017

Recently, owing to increased interest in low-carbon energy supplies, renewable energy sources such as photovoltaics and wind turbines in distribution networks have received considerable attention for generating clean and unlimited energy. The presence of energy storage systems (ESSs) in the promising field of active distribution networks (ADNs) would have direct impact on power system problems such as encountered in probabilistic distributed generation (DG) model studies. Hence, the optimal procedure is offered herein, in which the simultaneous placement of an ESS, photovoltaic-based DG, and wind turbine-based DG in an ADN is taken into account. The main goal of this paper is to maximize the net present value of the loss reduction benefit by considering the price of electricity for each load state. The proposed framework consists of a scenario tree method for covering the existing uncertainties in the distribution network's load demand as well as DG. The collected results verify the considerable effect of concurrent installation of probabilistic DG models and an ESS in defining the optimum site of DG and the ESS and they demonstrate that the optimum operation of an ESS in the ADN is consequently related to the highest value of the loss reduction benefit in long-term planning as well. The results obtained are encouraging.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.10a
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• pp.15-16
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• 2016

Ways to efficiently manufacture gloss exposed mass concrete at an inexpensive price, in other words, ways to paste transparent transfer paper onto the surface of a combined mold has been designated as New Technology Article 191 by the Ministry of Land, Infrastructure and Transport. But if the difference in the coefficient of linear expansion between the mold's and transfer paper's material causes temperature to rise or fall, a wrinkly surface can appear. Therefore this study, by experimentally comparing the deformation characteristics between the mold material and transfer paper material upon changes in temperature, seeks to serve as a basic reference point for selecting the optimal transfer paper for different mold types. Study results revealed that for molds, polyester resin transfer paper is optimal, and for aluminum molds, acrylic resin transfer paper is.

• Journal of the Economic Geographical Society of Korea
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• v.15 no.1
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• pp.95-115
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• 2012

The initial market of alternative-fuel vehicle (AFV) will show geographically uneven distribution due to AFV's high price, and thus efficient location model should consider spatial variation of demand. This paper estimates AFV trips by incorporating an AFV demand estimation model with origin-destination (OD) trips. The estimates are the input for the flow-refueling location model that maximizes the OD flows that can be refueled by the given number of stations considering AFV's limited range per refueling. A scenario analysis is conducted by varying assumptions in estimating demands and AFV acceptance rate. Optimal location alternatives for Orland metropolitan area are provided and results are compared.