• Journal of the East Asian Society of Dietary Life
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• v.26 no.2
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• pp.117-124
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• 2016

As the number of cafeterias at universities has increased, studies on student perception of price sensitivity at cafeterias have gained increased attention. Therefore, the study investigated the relationship between students and university cafeterias according to price sensitivity measurement (PSM). According to the analysis, the indifference price (IDP) was 3,444.06 Korean Won while the subsequent cumulative distribution percentage was approximately 17.68%. The optimal pricing point (OPP) was 3,233.73 Korean Won and the stress price (IDP-OPP) was 210.33 Korean Won. The point of marginal expensiveness (PME) was 4,602.24 Koean Won and the point of marginal cheapness (PMC) was 2,036.29 Korean Won. Therefore, the range of acceptable prices (RAP) was established as 2,565.95 Korean Won. In addition, the study examined differences between price sensitivity measurement (PSM) for the respondent subgroups. Hence, the results will provide a practical background for development of business plans for university cafeterias.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.8
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• pp.1504-1511
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• 2009

By development of renewable energies and high-efficient facilities and deregulated electricity market, the operation cost of distributed generation(DG) becomes more competitive. The amount of distributed resource is considerably increasing in the distribution network consequently. Also, international environmental regulations of the leaking carbon become effective to keep pace with the global efforts for low-carbon paradigm. It contributes to spread out the business of DG. Therefore, the operator of DG is able to supply electric power to customers who are connected directly to DG as well as loads that are connected to entire network. In this situation, community energy system(CES) having DGs is recently a new participant in the energy market. DG's purchase price from the market is different from the DG's sales price to the market due to the transmission service charges and etc. Therefore, CES who owns DGs has to control the produced electric power per hourly period in order to maximize the profit. If there is no regulation for carbon emission(CE), the generators which get higher production than generation cost will hold a prominent position in a competitive price. However, considering the international environment regulation, CE newly will be an important element to decide the marginal cost of generators as well as the classified fuel unit cost and unit's efficiency. This paper will introduce the optimal operation of CES's DG connected to the distribution network considering CE. The purpose of optimization is to maximize the profit of CES and Particle Swarm Optimization (PSO) will be used to solve this problem. The optimal operation of DG represented in this paper is to be resource to CES and system operator for determining the decision making criteria.

• Journal of Korean Society for Quality Management
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• v.22 no.2
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• pp.41-50
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• 1994

Consider a canning process where cans are filled with an expensive ingredient. Cans weighting above the specified limit are sold in a regular market for a fixed price, and underfilled cans are emptied and refilled at the expense of a reprocessing cost. In this paper, the effect of measurement error on the determination of the optimal process mean for a canning process is examined. It is assumed that the quantity X of ingredient in a can is normally distributed with unknown mean and known variance, and the observed value Y of X is also normally distributed with known mean and variance. A profit model is constructed which involves selling price. cost of ingredients, reprocessing cost. and cost from an accepted nonconforming can, and methods of finding the optimal process mean and the cutoff value on Y are presented. It is shown that the optimal process mean increases. and the expected profit decreases when the measurement error is relatively large in comparison to the process variance.

• Journal of Electrical Engineering and Technology
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• v.8 no.3
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• pp.436-445
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• 2013

The use of a demand response controller is necessary for electric devices to effectively respond to time varying price signals and to achieve the benefits of cost reduction. This paper describes a new formulation with the form of constrained optimization for designing an optimal demand response controller. It is demonstrated that constrained optimization is a better approach for the demand response controller, in terms of the ambiguity of device operation and the practicality of implementation of the optimal control law. This paper also proposes a design scheme to construct a demand response controller that is useful when a system controller is already adapted or optimized for the system. The design separates the demand response function from the original system control function while leaving the system control law unchanged. The proposed formulation is simulated and compared to the system with simple dynamics. The effects of the constraints, the system characteristics and the electricity price are examined further.

• Journal of Electrical Engineering and Technology
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• v.5 no.4
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• pp.530-537
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• 2010

By development of renewable energy and more efficient facilities in an increasingly deregulated electricity market, the operation cost of distributed generation (DG) is becoming more competitive. International environmental regulations of the leaking carbon become effective to reinforce global efforts for a low-carbon paradigm. Through increased DG, operators of DG are able to supply electric power to customers who are connected directly to DG as well as loads that are connected to entire network. In this situation, a community energy system (CES) with DGs is a new participant in the energy market. DG's purchase price from the market is different from the DG's sales price to the market due to transmission service charges and other costs. Therefore, CES who owns DGs has to control the produced electric power per hourly period in order to maximize profit. Considering the international environment regulations, CE will be an important element to decide the marginal cost of generators as well as the classified fuel unit cost and unit's efficiency. This paper introduces the optimal operation of CES's DG connected to the distribution network considering CE. The purpose of optimization is to maximize the profit of CES. A Particle Swarm Optimization (PSO) will be used to solve this complicated problem. The optimal operation of DG represented in this paper would guide CES and system operators in determining the decision making criteria.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.1
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• pp.131-143
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• 2017

As the number of tourists visiting Seoul are continuously increasing, the demand of an integrative tour pass is also increasing. However, only a few tour passes are available for the tourists in Seoul. In this paper, we propose a new tour pass called "Seoul Landmark Pass" targeting foreign individual travelers and investigate the marketability of the proposed tour pass. For the configuration of the Seoul Landmark Pass we listed 17 candidate attractions charging entrance fee in Seoul, referring to e-guidebook on Visit Seoul web site. Among them we selected 6 attractions using the checklist with the attributes that foreign tourists would prefer. We also performed SWOT analyzes on existing tour passes to determine the benefits to be included in the proposed tour pass. To investigate the marketability of the proposed tour pass we have surveyed the foreign individual tourists in Seoul. Using the survey data, we have analyzed the intent of purchase by age, visiting period, visiting purpose, frequency of visit, and nationality to identify target customers. The results show that the intent of purchase is high among the Chinese tourists at the age of twenties who visited Seoul for the first time or second times. Also, the individual tourists prefer to bundle T-money card with the proposed tour pass. Finally, we have provided a brief review of the Price Sensitivity Measurement (PSM) method and applied PSM to determine the acceptable price range and the optimal price of the proposed tour pass. The optimal price of the proposed tour pass is determined at 53,000 won including T-money card.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 1999.12a
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• pp.21-25
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• 1999

Planning support systems(PSS) add more advanced spatial analysis functions than Geographic information systems(GIS) and intertemporal functions to the functions of spatial decision support systems(SDSS). This paper reports the continuing development of a PSS providing a framework that facilitates urban planners and civil engineers in conducting coherent deliberations about planning, design and operation & maintenance(O&M) of water-distribution networks for urban growth management. The PSS using dynamic optimization model, modeling-to-generate-alternatives, value engineering(VE) and life-cycle cost(LCC) can generate network alternatives in consideration of initial cost and O&H cost. Users can define alternatives by the direct manipulation of networks or by the manipulation of parameters in the models. The water-distribution network analysis model evaluates the performance of the user-defined alternatives. The PSS can be extended to include the functions of generating sewer network alternatives, combining water-distribution and sewer networks, eventually the function of planning, design and O&H of housing sites. Capacity expansion by the dynamic water-distribution network optimization model using MINLP includes three advantages over capacity expansion using optimal control theory(Kim and Hopkins 1996): 1) finds expansion alternatives including future capacity expansion times, sizes, locations, and pipe types of a water-distribution network provided, 2) has the capabilities to do the capacity expansion of each link spatially and intertemporally, and 3) requires less interaction between models. The modeling using MINLP is limited in addressing the relationship between cost, price, and demand, which the optimal control approach can consider. Strictly speaking, the construction and O&M costs of water-distribution networks influence the price charged for the served water, which in turn influence the. This limitation can be justified in rather small area because price per unit water in the area must be same as that of neighboring area, i.e., the price is determined administratively. Planners and engineers can put emphasis on capacity expansion without consideration of the relationship between cost, price, and demand.

• Korean System Dynamics Review
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• v.12 no.2
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• pp.5-36
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• 2011

Seoul citizens are currently suffering from high housing price. Home prices have risen more rapidly than salaries so owning a housing unit (apartment, condominium, or single-family home) in Seoul is becoming more difficult than ever. Therefore, this research examines the behavior of average Seoul citizen in owning housing unit in Seoul, Korea, particularly in terms of the length of time required to afford a house unit. This research estimates that it will take about 18.75 years in maximum after getting a job (12.75 years after purchasing the housing unit) to own housing unit in Seoul that is currently valued at $300,000 where the growth rate of income is 2.97% and consumption price increases at a rate of 2.95% per annum. Finally in this research, the optimal growth rate of housing price is estimated ranged from 3.5 to 4.0% minimizing the loan payoff period.

• Particle and aerosol research
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• v.10 no.1
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• pp.19-25
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• 2014

In line with the expected price reduction of natural gas associated with the introduction of shale gas, it is expected that the optimal power mix for the electric power generation be changed. In this study, the reconfigured power mix is estimated with the varying natural gas price by using the Screening Curve Method (SCM). It is found that about 3% and 9% coal in the overall power mix is replaced with natural gas if the natural gas price falls 20% and 40% of the current price, respectively. It is also found that the reconfigured power mixes would provide the reduction of the emissions of air pollutants which are equivalent to 369 and 807 MUS$.

• Journal of Korea Technology Innovation Society
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• v.7 no.1
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• pp.111-129
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• 2004

The issues on the interconnection of telecommunications network are recently prevailed in the IT industry. In this study, we classify the network interconnection system into two categories: two way-same price model and two way-different price model. The purpose of this paper is to analyze economic characteristics of optimal settlement system according to each model. One of the most important policy implications we derive through this study is that symmetry between enterprises is required for policy maker or regulatory agency to set an efficient settlement system under two way-same price model, but that symmetry is not necessarily required under two way-same price model.