• Journal of Electrical Engineering and Technology
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• 제8권3호
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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.

• 동아시아식생활학회지
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• 제4권2호
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• pp.27-37
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• 1994

A survey was conducted to investigate consciousness of middle and high school students unsing fast food restaurants in Kwang-ju, from July 20 to August 20 in 1993. The results are follows; 1. There are many motives which drive students into fast food restaurants. Among those are its convenience as a place of meeting friends, pleasant and clean environment for eating, no time limit of staying there, hygiene of dining equipment and table ware. 2.The majority of the students used the fast food restaurants between 12:00 and 14:00 pm. It shows that time does not influence much on using there, because they answered in high percent that they use at any time. 3. Student usually pay individually and in some cases their friends or parents pay the bill. 4. Major factor in fast food selection was their tastes, nexts, were proper price, nutrition, and so on, They prefer their home food to restaurants fast foods. 5. The most of students have positive response to make traditional Korean foods into fast foods. The students, in particular, emphasized for the development of traditional Korean foods ; Sikhae and Sujonggwa(beverage), Docbokki, Japchae, kinds of rice cake and Jun. 6. Students suggested to be better fast food service, such as lowering the price, increasing the portion size and developing fast foods from the traditional Korean foods.

• 정보과학회 논문지
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• 제44권12호
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• pp.1258-1268
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• 2017

신속하고 정확한 시장의 물가 파악은 소비자 개인을 넘어 정부와 관련 기업의 주요 관심 사항이다. 그러나 국가 단위의 물가 데이터 취합은 적지 않은 시간과 비용이 필요하다. 특히 통계 데이터 관련 인프라가 미약한 개발도상국의 경우 물가 지표 파악은 일 혹은 주 단위로 지연되어 국가의 정책 결정에 필요한 주요한 데이터의 부재가 있을 뿐만 아니라 투자 잠재성을 저하시킨다. 이러한 배경에서 이 연구는 온라인 소셜 네트워크 빅데이터를 활용한 실시간 물가 예측(Nowcast) 모델을 제시한다. 제안하는 모델은 트위터와 같은 온라인 빅데이터를 수집 및 분석함으로써 주요 소비재 시장물가를 실시간으로 단기 예측하는 알고리즘으로, 실제 15개월간 인도네시아를 대상으로 주요 식자재의 일별 물가 추이 예측에서 높은 정확도를 보임을 검증하였다. 해당 모델은 다양한 언어와 상품군으로 확장 가능하며, 기존 경제 통계를 보조함으로써 시장동향의 파악으로 정부와 기업의 전략 수립에 기여할 것으로 기대된다.

• 유통과학연구
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• 제13권5호
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• pp.71-82
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• 2015

Purpose - The purpose of this study is to investigate risk price implied from the pricing kernel of Korean stock distribution market. Recently, it is considered that the quantitative easing programs of major developed countries are contributing to a reduction in global uncertainty caused by the 2007~2009 financial crisis. If true, the risk premium as compensation for global systemic risk or economic uncertainty should show a decrease. We examine whether the risk price in the Korean stock distribution market has declined in recent years, and attempt to provide practical implications for investors to manage their portfolios more efficiently, as well as academic implications. Research design, data and methodology - To estimate the risk price, we adopt a non-parametric method; the minimum norm pricing kernel method under the LOP (Law of One Price) constraint. For the estimation, we use 17 industry sorted portfolios provided by the KRX (Korea Exchange). Additionally, the monthly returns of the 17 industry sorted portfolios, from July 2000 to June 2014, are utilized as data samples. We set 120 months (10 years) as the estimation window, and estimate the risk prices from July 2010 to June 2014 by month. Moreover, we analyze correlation between any of the two industry portfolios within the 17 industry portfolios to suggest further economic implications of the risk price we estimate. Results - According to our results, the risk price in the Korean stock distribution market shows a decline over the period of July 2010 to June 2014 with statistical significance. During the period of the declining risk price, the average correlation level between any of the two industry portfolios also shows a decrease, whereas the standard deviation of the average correlation shows an increase. The results imply that the amount of systematic risk in the Korea stock distribution market has decreased, whereas the amount of industry-specific risk has increased. It is one of the well known empirical results that correlation and uncertainty are positively correlated, therefore, the declining correlation may be the result of decreased global economic uncertainty. Meanwhile, less asset correlation enables investors to build portfolios with less systematic risk, therefore the investors require lower risk premiums for the efficient portfolio, resulting in the declining risk price. Conclusions - Our results may provide evidence of reduction in global systemic risk or economic uncertainty in the Korean stock distribution market. However, to defend the argument, further analysis should be done. For instance, the change of global uncertainty could be measured with funding costs in the global money market; subsequently, the relation between global uncertainty and the price of risk might be directly observable. In addition, as time goes by, observations of the risk price could be extended, enabling us to confirm the relation between the global uncertainty and the effect of quantitative easing. These topics are beyond our scope here, therefore we reserve them for future research.

• 한국콘텐츠학회논문지
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• 제16권8호
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• pp.97-106
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• 2016

불법다운로드에 대한 사회적 규범과 불법다운로드 이용의향 간의 관계를 다룬 선행연구들은 혼재된 연구 결과를 제시하고 있다. 본 연구에서는 이러한 연구결과들의 불일치 원인을 조절요인 때문으로 판단하고, 저작권법에 대한 이용자 태도와 콘텐츠 구매 시 가격중요성이 수행하는 조절적 역할을 확인해 보고자 하였다. 이를 위해 사회적 규범을 주관적 규범과 집단적 규범으로 나누고, 이들 각각의 규범 인식과 불법다운로드 이용의향 간 관계에서 저작권법 태도와 콘텐츠 가격 중요성 각각이 수행하는 조절적 역할 가설들을 설정하였다. 가설검증 결과, 총 4개 조절효과 가설 중 주관적 규범과 저작권법 태도간의 상호작용을 다룬 가설은 기각되고, 나머지 3개 가설은 채택할 수 있었다. 즉 불법다운로드에 대해 긍정적으로 생각하는 집단규범이 강할수록 불법다운로드 이용의향은 증가하지만 저작권법에 대해 긍정적 태도를 가질수록 그 영향력은 줄어드는 것으로 나타났다. 또한 불법다운로드에 대해 긍정적인 주관적 규범과 집단적 규범 각각이 불법다운로드 이용의향에 미치는 영향력은 콘텐츠 구매 시 가격을 중요하게 인식할수록 증가함을 확인하였다.

• 한국식품영양학회지
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• 제11권5호
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• pp.528-535
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• 1998

This study was conducted to provide some basic information for promoting efficiency in university food services. Subjects were 309 students of A, B and C university. The survey was done by questionaires, and the data were analyzed by SAS program. The quantity and nutritional values of food was evaluated as appropriate but temperature and freshness of food, use of seasonal food, variety of menu were indicated as unsatisfactory. Male students marked lower points on the price but female students gave lower scores for variety of menu and use of seasonl food. Employee hygiene fast service and neatness and kindness of workers were evaluated as appropriate but food sanitation and cleanness of dishes were indicated as unsatisfactory. A and B university students scored low marks on food sanitation. Female students scored higher marks on the employee's neatness. Arrangement of tables and chairs, location of returning utensils, location of counter use of menu board and ventilation facilities were scored as average but interior decoration and heating facilities were scored as low level. Students of a school scored low mark on the arrangement of tables, location of counter, heating facilities and interior decoration but students of B school scored low mark on the use of menu board. Calmness and comfortableness of dining hall was unsatisfactory but location of dining hall, serving time and waiting time were evaluated as appropriate. In conclusion improvements for temperature and freshness of food, use of seasonal food, variety of menu, food sanitation, cleanness of dishes, interior decoration, heating facility and resting area were indicated as necessary.

• Carbon letters
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• 제15권3호
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• pp.162-170
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• 2014

Pitch is an attractive raw material for carbon fiber precursors due to its low cost stemming from its availability as a residue of coking and petroleum processes. Ford Motor Company reported a carbon fiber target price of $11.0/kg by using a fast cycle-time manufacturing method with carbon fiber in an inexpensive format, allowing for an average retail price of gasoline of $3.58/gallon. They also recommended the use of carbon fiber with strength of 1700 MPa, modulus of 170 GPa, and 1.5% elongation. This study introduced a ca. $5.5{\mu}m$ carbon fiber with 2000 MPa tensile strength obtained from a precursor through simple distillation of petroleum residue. Petroleum pitch based carbon nanofibers prepared via electrospinning were characterized and potential applications were introduced on the basis of their large specific surface area and relatively high electrical conductivity.

• Asia Pacific Journal of Business Review
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• 제1권1호
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• pp.1-22
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• 2016

The prediction of prices of agricultural products in the agriculture IT sector plays a significant role in the economic life of consumers and anyone engaged in agricultural business, and as these prices fluctuate more often than do other prices, the prediction of these prices holds a great deal of research promise. For this reason, academic literature has provided studies on the factors influencing the prices of agricultural products and the price index. However, as these factors vary, they are difficult to predict, resulting in the challenge of acquiring quantitative data. China is one example of a country without a reliable prediction system for prices of agricultural products. Fortunately, disclosed heterogeneous data can be found on the Internet, which allows for the effective collection of factors related to the prediction of these product prices through the use of text mining. The data provided online is valuable in that they reflect the opinions of the general public in real-time. Accordingly, this study aims to use heterogeneous data from the Internet and suggest a model predicting the prices of agricultural products before functional analyses. Toward this end, data analyses were conducted on the Chinese agricultural products market, one of the largest markets in the world.

• Management Science and Financial Engineering
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• 제20권1호
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• pp.21-26
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• 2014

A lot of researches have been conducted to estimate the volatility smile effect shown in the option market. This paper proposes a method to approximate an implied volatility function, given noisy real market option data. To construct an implied volatility function, we use Gaussian Processes (GPs). Their output values are implied volatilities while moneyness values (the ratios of strike price to underlying asset price) and time to maturities are as their input values. To show the performances of our proposed method, we conduct experimental simulations with Korean Equity-Linked Warrant (ELW) market data as well as toy data.

• 전기학회논문지
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• 제64권7호
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• pp.1125-1129
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• 2015

Increasing peak load is one of the major concerns about operation of urban railroad systems. Since ESSs (Energy Storage Systems) have a great potential for shaving the peak load, there has been a growing interest in the use of ESS for peak load reduction. Also, ESS can be optimally scheduled to minimize the electricity purchasing cost under a given ToU (Time-of-Use) tariff by taking advantage of electricity price difference between peak and off-peak time. This paper presents a Mixed Integer Programming (MIP)-based ESS scheduling method to minimize the electricity purchasing cost under a ToU tariff for an urban railroad system.