• Journal of Internet Computing and Services
• /
• v.21 no.5
• /
• pp.39-48
• /
• 2020

Recently, the study and development of environment-friendly energy technique have increased in worldwide due to environmental pollution and energy resources problems. In vehicle industry, the development of electric vehicle(EV) is now on progress, and also, many other governments support the study and development and make an effort for EV to become widely available. In addition, though they strive to construct the EV infra such as a charge station for EV, the techniques related to managing charge demand and peak power are not enough. The standard of EV communication has been already established as ISO/IEC 15118, however, most of implemented EVs and EV charge stations do not support any communication between each of them. In this paper, an improved slow charge scheme for non-communication EVs is proposed and designed by using predicting charge demand. The proposed scheme consists of distributed charge model and charge demand prediction. The distributed charge model is designed to manage to distribute charge power depending on available charge power and charge demand. The charge demand prediction is designed to be used in the distributed charge model. The proposed scheme is based on the collected data which were from EV slow charge station in business building during the past 1 year. The system-level simulation results show that the waiting time of EV and the charge fee of the proposed scheme are better than those of the conventional scheme.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 1996.04a
• /
• pp.324-327
• /
• 1996

In this paper, the affecting factors of the access demand for the cellular service are derived, and the access demand function of the cellular service is estimated. The results obtained in this study are as follows: First, the price (access charge) and the income elasticities of cellular services there exists a network externality in cellular communication services. Third, the technological capability of the service provider has played an essential role in expanding the size of subscribers. Fourth, the access demand of cellular communication service is not sensitive to the usage charge. According to the above results, it can be inferred that if the access charge is lowered, the number if subscribers will increase to the critical mass, and then the cellular communication market will grow up to a saturation point naturally.

• Journal of Korea Technology Innovation Society
• /
• v.1 no.3
• /
• pp.374-385
• /
• 1998

This study is estimates telephone service demand based on empirical studies of telecommunication service demand model. First, the telephone charge(call price index) by each location and subscription fee bring about a negative effect to telephone distribution rate: while the other explanatory variables bring about a positive effect. Second, the flexibility of telephone charge in A location(relevant location) and the flexibility between the distance of A location and B location are negative values, while the flexibility of other explanatory variables is represented in a positive value. This means that the long distance call numbers from A location to B location are in inverse proportion against the phone charge(call price index) of A location and against the distance between A location and the distance of other locations except A location, while they are in direct proportion with an average call number per minute from A location to other locations except A location, and also with subscription numbers of A location, other subscribers in locations other than A location, and the total expenditures of A location.

• Journal of Korea Technology Innovation Society
• /
• v.14 no.3
• /
• pp.622-646
• /
• 2011

This paper analyses the effects of mobile telecommunications market's interconnection charge on consumer welfare between 2000 and 2010 by estimating price elasticity of demand with using log linear model and augmented Alexander et al(2000)'s model. The results show that consumer welfare is about 6 trillion won in 2009 and an upward trend. In the 2nd analysis, the decline in interconnection charge raise consumer welfare but, asymmetric interconnection and current TD-BU LRIC system have negative(-) relation with consumer welfare. Hence we need to revise interconnection policy frame.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.4
• /
• pp.85-92
• /
• 2018

Reductions of the electricity charge are achieved by demand management of the load. The demand management method of the load using ESS involves peak shifting, which shifts from a high demand time to low demand time. By shifting the load, the peak load can be lowered and the energy charge can be saved. Electricity charges consist of the energy charge and the basic charge per contracted capacity. The energy charge and peak load are minimized by Linear Programming (LP) and Quadratic Programming (QP), respectively. On the other hand, each optimization method has its advantages and disadvantages. First, the LP cannot separate the efficiency of the ESS. To solve these problems, the charge and discharge efficiency of the ESS was separated by Mixed Integer Linear Programming (MILP). Nevertheless, both methods have the disadvantages that they must assume the reduction ratio of peak load. Therefore, QP was used to solve this problem. The next step was to optimize the formula combination of QP and LP to minimize the electricity charge. On the other hand, these two methods have disadvantages in that the charge and discharge efficiency of the ESS cannot be separated. This paper proposes an optimization method according to the situation by analyzing quantitatively the advantages and disadvantages of each optimization method.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.13 no.3
• /
• pp.1674-1688
• /
• 2019

As environmental pollution and fossil fuel energy problems from fuel vehicle have occurred, the interest of electric vehicle(EV) has increased. EV industry and energy industry have grown dynamically in these days. It is expected that the next generation of primary transportation will be EV, and it is necessary to prepare EV infra and efficient energy management such as EV communication protocol, EV charge station, and smart grid. Those EV and energy industry fields are now on growth. Also, the study and development of them are now in progress. In this paper, distributed charge signal processing software for smart slow and quick EV charge is proposed and designed for dealing with EV charge demand. The software consists of smart slow and quick EV charge schedule engine and EV charge power distribution core. The software is designed to support two charge station types. One is normal EV charge station and the other is bus garage EV charge station. Both two types collect the data from EV charge stations, and then analyze the collected data. The software suggests optimized EV charge schedule and deliveries EV charge power distribution information to power switchboard system, and the designed software is implemented on embedded system. It is expected that the software provides efficient EV charge schedule.

• Journal of Technologic Dentistry
• /
• v.38 no.4
• /
• pp.381-399
• /
• 2016

Purpose: The purpose of this study was to examine the awareness of dental technicians on demand for this occupation, their occupational satisfaction and factors affecting the supply and demand of dental technicians. Methods: A self-reported questionnaire survey was carried out by having convenience sampling as 200 dental technicians who work in Seoul Metropolis, Gyeonggi-do Province, Chungnam-do Province from September 26, 2016 to October 15. An analysis of the collected data was computationally processed by using SPSS Win 19.0 program. An analytical technique was made by using statistical techniques such as frequency & percentage, T-test, One-way ANOVA or ANCOVA analysis. The following are the analytical results of the collected materials. Results: When the occupational satisfaction of the selected subjects was analyzed, there were significant differences according to academic credential, marital status, duties in charge, position and monthly income. Their preference for this occupation as a lifelong job significantly varied with age, academic credential, duties in charge, position and monthly income. Their turnover plans significantly differed with age, position, career and monthly income(p<.05). As a result of analyzing what factors affected manpower supply and demand, they placed a lot of importance on the areas of required time and satisfaction, and they attached a less importance to the areas of interpersonal relationships and workload. Their total average score in these areas was 3.06. Conclusion: As a result of research, the manpower supply and demand factors that exerted significant influences on occupational satisfaction were pride. required time and the appropriateness of the number of workers, and the manpower supply and demand factors that had significant impacts on job preference as a lifelong occupation were satisfaction, pride and the appropriateness of the number of workers. The manpower supply and demand factors that affected turnover plans in a significant way were pride, satisfaction and the appropriateness of the number of workers.

• Journal of Digital Contents Society
• /
• v.9 no.1
• /
• pp.69-75
• /
• 2008

Video-on-demand (VOD) service allows subscribers to view any video whenever they want. With the development of the high speed computer networks, web-based VOD services are available. To support VOD services, charging scheme is necessary. Pay-per-view is an effective charging scheme for VOD services. Pay-per-view allows the subscribers to pay for what they have viewed. Privacy is another important attribute for VOD services. The subscribers may not want to reveal what they have viewed to anyone including the VOD provider. Anonymity makes it complicated to calculate charge for the VOD service. An approach that achieves both anonymity and pay-per-view charge calculation is necessary. In this paper, anonymous web-based VOD service is proposed. The proposed approach also gives pay-per-view capability.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.34 no.1B
• /
• pp.34-46
• /
• 2009

The remarkable growth of Korean telecommunication market has based on the introduction of competition as well as mobile technology like CDMA. It was well Down that such a conspicuous growth has been towed by mobile service rather than fixed telephone service. In telecommunications service the number of subscribers to mobile was over 40 millions in 2006 and also, while the traffic amount of fixed telephone has been more decreased, that of mobile, which already outnumbers the fixed, has been constantly increased and will be much more in future. It will accelerate the substitution of access and call demand of fixed service by mobile. This change of technology and demand does affect directly the market performance of telecommunications. And regulation has also an effect on market structure, which finally affects on market performance. In this paper we suppose the fixed and mobile telecommunications services are in a same industry. After reviewing the relations among the demand, cost, charge structure and revenue structure in the one fixed and mobile telecommunications market using the framework of an industrial structure analysis, we discuss the current issues of telecommunications regulation and implications for the future regulation.

• ETRI Journal
• /
• v.26 no.6
• /
• pp.665-668
• /
• 2004

The introduction of a mobile virtual network operator (MVNO) system is expected to increase consumer benefits, boost competition in the mobile market, utilize idle bandwidth, and expedite mobile-fixed line convergence and growth in the mobile Internet market. This research endeavors to study the optimal access charge for an MVNO system, which is expected to be introduced to the Korean mobile communications market. We found that the optimal access charge is higher in the interdependent model than in the independent model if demand for mobile phone service is based on a substitution relationship. We also found that the optimal access charge is higher than the marginal cost.