• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.568-579
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• 2018

Virtual power plants can be regarded as systems that have entered the network after restructure of power systems. In fact, these plants are a set of consumers capable of consuming and generating power. In response to widespread implementation of plug-in hybrid electric vehicles, further investigation of energy management in this type of power plants seems to be of great value. In effect, these vehicles are able to receive and inject power from/into the network. Hence, study of the effects of these vehicles on management of virtual power plants seems to be illuminative. In this paper, management of power consumption/generation in virtual power plants has been investigated in the presence of hybrid electric vehicles. The objective function of virtual power plants problem management is to minimize the overall costs including not only the costs of energy production in power generation units, fuels, and degradation of batteries of vehicles, but also the costs of purchasing electricity from the network. Furthermore, the constraints on the operational of plants, loads and hybrid vehicles, level of penalty for greenhouse gas emissions ($CO_2$ and $NO_x$) produced by power plants and vehicles, and demand response to the immediate price of market have all been attended to in the present study. GAMS/Cplex software system and sample power system have been employed to pursue computer implementation and simulation.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.5
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• pp.913-921
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• 2021

The objective of the study is to investigate the impact of the COVID-19 pandemic on Saudi Arabia stock market. The study relied on the data of the daily closing stock market price index Tadawul All Share Index (TASI), and the number of daily cases infected with COVID-19 during the period from March 15, 2020, to August 10, 2020. The study employs the Vector Auto-Regressive (VAR) model, the Impulse Response Function (IRF) and Autoregressive Conditional Heteroscedasticity (ARCH) models. The results of the correlation matrix and the Impulse Response Function (IRF) show that stock market returns responded negatively to the growth in COVID-19 infected cases during the pandemic. The results of ARCH model confirmed the negative impact of COVID-19 pandemic on KSA stock market returns. The results also showed that the negative market reaction was strong during the early days of the COVID-19 pandemic. The study concluded that stock market in KSA responded quickly to the COVID-19 pandemic; the response varies over time according to the stage of the pandemic. However, the Saudi government's response time and size of the stimulus package have played an important role in alleviating the impacts of the COVID-19 pandemic on Saudi Arabia Stock Market.

• Journal of Korea Port Economic Association
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• v.37 no.2
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• pp.73-89
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• 2021

The handysize bulk carriers are capable of transporting a variety of cargo that cannot be transported by mid-large size ship, and the spot chartering market is active, and it is a market that is independent of mid-large size market, and is more risky due to market conditions and charterage variability. In this study, Granger causality test, the Impulse Response Function(IRF) and Forecast Error Variance Decomposition(FEVD) were performed using monthly time series data. As a result of Granger causality test, coal price for coke making, Japan steel plate commodity price, hot rolled steel sheet price, fleet volume and bunker price have causality to Baltic Handysize Index(BHSI) and charterage. After confirming the appropriate lag and stability of the Vector Autoregressive model(VAR), IRF and FEVD were analyzed. As a result of IRF, the three variables of coal price for coke making, hot rolled steel sheet price and bunker price were found to have significant at both upper and lower limit of the confidence interval. Among them, the impulse of hot rolled steel sheet price was found to have the most significant effect. As a result of FEVD, the explanatory power that affects BHSI and charterage is the same in the order of hot rolled steel sheet price, coal price for coke making, bunker price, Japan steel plate price, and fleet volume. It was found that it gradually increased, affecting BHSI by 30% and charterage by 26%. In order to differentiate from previous studies and to find out the effect of short term lag, analysis was performed using monthly price data of major cargoes for Handysize bulk carriers, and meaningful results were derived that can predict monthly market conditions. This study can be helpful in predicting the short term market conditions for shipping companies that operate Handysize bulk carriers and concerned parties in the handysize chartering market.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.587_588
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• 2009

본 논문에서 전력 시스템 운영자의 trigger poin와 수요 반응 프로그램 참여자의 가격 탄력성에 따라 수요 반응 이후의 전기 가격을 예측하여 경제성 수요 반응 프로그램에 어떤 영향을 끼치는 지 살펴보고 운영자가 수요 반응 프로그램 반응 정보를 쉽게 파악할 수 있게 PR을 제안한다.

• International Commerce and Information Review
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• v.7 no.4
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• pp.59-76
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• 2005

In this research, electronic commercial web-sites of artwork are analysed with ten marketing success factors such as, low price, variety of products convenience of shopping, ensure credibility DB marketing, providing information, virtual community, preoccupying the marketing, quick response, and strategic cooperation. The analysis showed that the main problem of the Korean fine art market is the lack of demand. Though the problem of the offline fine art market is not to be solved by websites, it seems that the solution should be brought through the operation of websites with long-term plans and patience.

• 한국IT서비스학회:학술대회논문집
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• 2006.11a
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• pp.80-85
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• 2006

현재 많은 인터넷 콘텐츠 서비스가 다양한 방식의 유료 서비스로 제공되고 있지만 다양하고 복잡한 콘텐츠 서비스의 특성상 가격 책정에는 많은 어려움이 있다. 본 연구는 인터넷 영화관을 대상으로 하여 사용자들이 서비스를 선택할 때 가장 고려하는 속성을 분석하고 속성과 속성 수준을 설정한 프로파일들의 가격반응함수를 구하였다. 또한, 선형${\cdot}$곱셈${\cdot}$유인${\cdot}$구텐베르그 모델 중 가장 적합한 모델을 추정하고 독점 영역과의 관계를 살펴봄으로써 각 기업들이 서비스의 가격을 책정함에 있어서 가장 수익성 높고 적합한 전략을 설정할 수 있도록 방향을 제시하였다.

• Korean Journal of Poultry Science
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• v.45 no.3
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• pp.219-228
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• 2018

This study was conducted twice to investigate egg purchase behavior and perception on animal welfare of Korean consumers. This study included women, who were the main decision makers and caretakers in the household, and men with one-person household. This survey was conducted with by the Computer Assisted Web Interview and Gang Survey methods. On the key considerations factor, the highest response rate was considered to be 'price', and the response rate of considering 'packing date' increased in the second survey. At a reasonable price based on 10 eggs, the response rate was the highest at 53.8% and 42.9% in both the first and second surveys and the appropriate price averages were 2,482 won and 2,132 won, respectively. The highest rate of purchase of egg consumers from 'Large Mart' followed by 'Medium sized supermarket' and 'Chain supermarket'. As for the awareness about animal welfare, the recognition ratio (73.5%) was higher in the result of the second survey than the first. The cognitive period of animal welfare was 59.0% before the insecticide egg crisis and 41.0% thereafter. Regarding whether or not they have ever seen an animal welfare certification mark and an animal welfare animal farm certification mark, 59.6% of respondents said that they saw it for the first time and 37.6% answered that they knew the animal welfare certification mark. On the animal welfare system, the 'free-range' response rate was the highest at 85.8%. The 'free-range' fit response decreased by 34.2%p, while the 'barn' and 'European type' fit response increased by 13.2%p and 24.1%p, respectively. The number of 'I have never seen' and 'I have ever eaten' responses to the recognition and eating experience of animal welfare certified eggs decreased while the number of those who answered 'Have ever seen' and 'Have eaten' increased. The answer of purchasing animal welfare certified eggs at department stores, organic farming cooperatives, and internet shopping malls was higher than that of buying conventional eggs. Of the total respondents, 92.0% were willing to purchase an animal welfare egg before the price was offered, but after offering the prices of animal welfare eggs, the intention to purchase was 62.7%, which was about 30%p lower than before. The reason for purchasing an animal welfare certified egg was the highest score of 71.0% for 'I think it is likely to be high in food safety', and 38.1% for 'I think the price is high' for lack of intention to purchase. In the sensory evaluation of animal welfare eggs, egg color and skin texture of conventional eggs were significantly higher than those of certified welfare eggs (P<0.05), and boiled eggs showed that egg whites of animal welfare certified eggs were more (P<0.05). As a result, the results of this study will contribute to the activation of the animal welfare certification system for laying hens by providing basic data on consumer awareness to animal welfare certified farmers.

• Korean journal of food and cookery science
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• v.26 no.2
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• pp.129-137
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• 2010

The purposes of this study were to understand the influence of perceived service quality in upscale Korean restaurants on a customer's feeling response and revisit intent, and to empirically analyze whether a customer's feeling response plays a mediating role between the service quality and revisit intent. Based on a total 303 samples obtained from the empirical research, this study reviewed the reliability and fitness of the research model and verified a total of 2 hypotheses using the Amos program. The hypothesized relationships in the model were tested simultaneously by using a structural equation model(SEM). The proposed model provided an adequate fit to the data, ${\chi^2}_{(df=263)}=557.397$, CMIN/df 2.119, RMR .09, GFI .88, AGFI .86, NFI .94, CFI .97, RMSEA .06. The major results of this study can be outlined as follows: Price & value($\beta=.40$), food quality($\beta=.26$) and atmosphere($\beta=.15$) had a significant positive effect on the customer's feeling response, and the customer's feeling response($\beta=.65$) had a significant positive effect on revisit intent. In addition, the effect of the perceived service quality in upscale Korean restaurants on revisit intent was found to be partially mediated by the customer's feeling response. Limitations and future research directions are also discussed.

• ETRI Journal
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• v.42 no.4
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• pp.585-595
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• 2020

Integration of multiple communication technologies in a smart grid (SG) enables employing cognitive radio (CR) technology for improving reliability and security with low latency by adaptively and effectively allocating spectral resources. The versatile features of the CR enable the smart meter to select either the unlicensed or the licensed band for transmitting data to the utility company, thus reducing communication outage. Demand response management is regarded as the control unit of the SG that balances the load by regulating the real-time price that benefits both the utility company and consumers. In this study, joint allocation of the transmission power to the smart meter and consumer's demand is formulated as a two stage multi-armed bandit game in which the players select their optimal strategies noncooperatively without having any prior information about the media. Furthermore, based on historical rewards of the player, a real-time pricing adaptation method is proposed. The latter is validated through numerical results.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2008.10a
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• pp.520-524
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• 2008

This research verifies the phenomenon of which the Momentum and Reversal effect of stock price would depend on the subject of investment in the point of view of the Behavior Finance hypothesis. For the experiment, this paper uses the KOSPI200 daily data and Net Investment Flow from Jan. 1999 to Dec. 2006. And we analyze the marginal profit and loss with foreigners, individual investors, and institutions. We verify the response of the subjects of investment based on the CAR for 3 days after more than 3 percent rising or drop. We also verify the response with respect to the ascending and descending trend based on the profit trend and subjects' behaviors a week before the drop.