• 대한산업공학회지
• /
• 제37권2호
• /
• pp.132-143
• /
• 2011

This paper deals with a coal supply planning problem for power plants. We propose a mathematical optimization model to make decisions for coal pile sections, movement of reclaimers, and operation time of conveyor belts. The objective of the proposed model is to minimize the total operation time of conveyor belts and total movement time of reclaimers. The algorithm firstly selects a pile section by considering both the location of reclaimers and the stock amount on that pile section. And then the shortest path from the selected pile section has to be put into the operation schedule and check whether the total operation time is satisfied. Then finally the new schedule is updated. To this end, we have tested the proposed algorithm comparing with the general standard optimization package for the simplified problem SCSPP. From the numerous test runs for comparing with the existing coal supply scheduling methods, We see that the proposed model may improve the coal supply operation by reducing significant coal supply costs.

• 대한산업공학회지
• /
• 제39권1호
• /
• pp.30-45
• /
• 2013

Predicting monthly electricity price has been a significant factor of decision-making for plant resource management, fuel purchase plan, plans to plant, operating plan budget, and so on. In this paper, we propose a sophisticated prediction model in terms of the technique of modeling and the variety of the collected variables. The proposed model hybridizes the semi-supervised learning and the artificial neural network algorithms. The former is the most recent and a spotlighted algorithm in data mining and machine learning fields, and the latter is known as one of the well-established algorithms in the fields. Diverse economic/financial indexes such as the crude oil prices, LNG prices, exchange rates, composite indexes of representative global stock markets, etc. are collected and used for the semi-supervised learning which predicts the up-down movement of the price. Whereas various climatic indexes such as temperature, rainfall, sunlight, air pressure, etc, are used for the artificial neural network which predicts the real-values of the price. The resulting values are hybridized in the proposed model. The excellency of the model was empirically verified with the monthly data of electricity price provided by the Korea Energy Economics Institute.

• 한국지능정보시스템학회:학술대회논문집
• /
• 한국지능정보시스템학회 1999년도 춘계공동학술대회-지식경영과 지식공학
• /
• pp.105-113
• /
• 1999

최근 데이터와 데이터베이스의 폭발적 증가에 따라 무한한 데이터 속에서 정보나 지식을 찾고자하는 지식채굴과정(Knowledge discovery process)에 대한 관심이 높아지고 있다. 특히 기업 내외부 데이터베이스 뿐만 아니라 데이터웨어하우스(data warehouse)를 기반으로 하는 OLAP 환경에서의 데이터와 인터넷을 통한 웹(web)에서의 정보 등 정보원의 다양화와 첨단화에 따라 다양한 환경 하에서의 지식 채굴과정이 요구되고 있다. 본 연구에서는 인터넷 상의 지식을 효과적으로 채굴하기 위한 지식채굴과정을 제안한다. 제안된 지식채굴과정은 명시지(explicit knowledge)외에 암묵지(tacit knowledge)를 지식채굴과정에 반영하기 위해 선행지식베이스(prior knowledge base)와 선행지식관리시스템(prior knowledge management system)을 이용한다. 선행지식관리시스템은 퍼지인식도(fuzzy cognitive map)를 이용하여 선행지식베이스를 구축하여 이를 통해 웹에서 찾고자 하는 유용한 정보를 정의하고 추출된 정보를 지식변환시스템(knowledge transformation system)을 통해 통합적인 추론과정에 사용할 수 있는 형태로 변환한다. 제안된 연구모형의 유용성을 검증하기 위하여 재무자료에 선행지식을 제외한 자료와 선행지식을 포함한 자료를 사례기반추론 (case-based reasoning)을 이용하여 실험한 결과, 제안된 지식채굴과정이 유용한 것으로 나타났다.

• 한국정보처리학회논문지
• /
• 제7권9호
• /
• pp.2783-2796
• /
• 2000

전자상거래 시스템에서 패키지 상품의 구매가 이루어지기 위해서는 패키지 상품을 구성하는 상품들이 구비되어 있어야 할뿐만 아니라 충분한 수량이 확보되어 있어야만 구매자의 요구가 있을 때 이를 실시간으로 처리할 수 있게 된다. 그리고 다수의 사용자가 동시에 가상쇼핑몰에 접근하여 패키지 상품을 구매하고자 할 때에도 상품에 대한 동시성 제어가 효율적으로 이루어져야만 한다. 본 논문에서는 고정형 패키지와 맞춤형 패키지상품 구매 시 상품선택과 구매가 효율적으로 이루어지도록 하기 위해서 모든 상품에 대한 실 수량과 판매가능 수량정보를 유지토록 함으로써 구매자의 요구를 실시간으로 처리할 수 있도록 하였고, 트랜잭션의 처리율이 향상되도록 하였다. 그리고 트랜잭션의 동시성 제어를 효율적으로 하기 위해서 잠금을 기반으로 한 동시성제어 알고리즘을 제시하였다.

• 한국콘텐츠학회논문지
• /
• 제7권7호
• /
• pp.161-170
• /
• 2007

국 내외적으로 e-비즈니스는 일반적인 상거래 유형으로 자리 잡고 있다. 최초 e-비즈니스는 전자상거래라는 용어로 시작되었다. 그러나 점점 단순한 전자상거래보다 포괄적인 전자상거래 방식으로 변화되었다. 이러한 시점에서 한국의 e-비즈니스 시장에 대한 연구를 통해 성숙된 e-비즈니스 시장의 진입과 세계시장을 이끌 수 있는 토대를 마련하고자 한다. 이를 위해 한국 시장의 e-비즈시장 활성화를 위한 핵심성공요인의 성숙 단계를 측정하였다. 시간의 흐름에 따라 변화되는 핵심성공요인 의 중요도를 측정하여 한국 시장에서의 e-비즈니스의 활성화의 수준을 분석하였다. 이를 통해, 향후 e-비즈니스 시장의 발전 방향을 예측하고, 이에 대응할 수 있는 방안을 제공하고자 한다.

• 유통과학연구
• /
• 제11권2호
• /
• pp.5-10
• /
• 2013

Purpose - The current research examines the effect of life cycle stages on capital structure of listed companies in Tehran Stock Exchange. Research design, data, methodology - By aid of 685 year-company data, which collected from financial statements of companies during 2006-2012, first, the companies, are classified into three groups including companies in growth, maturity and decline stages. After removing the companies, which were not in accordance with life cycle model, 86 companies were selected to test two main hypotheses of the research. Results - The results show that the capital structure of the sample companies is different in various life cycle stages. More investigation by LSD test also revealed that the total debt to total assets ratio means of the companies in growth stages were significantly different from those companies in maturity stages and those in growth stages had high level of debt to assets ratio. Conclusions - The result showed the average amount of the working capital for companies in three stages are significantly different and due to high level of operation of the companies in maturity and decline stages, these companies held high amount of working capital than those in the growth stages.

• International journal of advanced smart convergence
• /
• 제9권3호
• /
• pp.17-27
• /
• 2020

With the continuous development and application of Internet technology, in recent years, new technologies such as cloud computing, big data, the Internet of Things, and AI are becoming more and more familiar to the general public. The development of a digital society has entered a new period of development. In this paper, we used on the 2018 annual data of 50 listed companies with blockchain concept stocks in China. Using data envelopment analysis (DEA) to study and analyze the input-output efficiency, it can be concluded that the input-output efficiency of 50 listed companies is very different. Inefficient companies are as high as 62%. Most companies have a large room for improvement in input-output efficiency due to uneconomical scale or inefficient technology. In order to better improve the company's input-output efficiency, one must improve the efficiency of resource utilization, optimize the company's research and development costs and the input and management of technical personnel; the second is to increase technological innovation and business innovation.

• Journal of Forest and Environmental Science
• /
• 제34권1호
• /
• pp.12-23
• /
• 2018

Quantitative information on biomass and available nutrients are essential for developing sustainable forest management strategies to regulate atmospheric carbon. An attempt was made at Chilapatta Reserve Forest in Duars region of West Bengal to quantify its above and below ground carbon along with available "N", "P" and "K" in the soil. Stratified random nested quadrats were marked for soil, biomass and litter sampling. Indirect or non-destructive procedures were employed for biomass estimation. The amount of these available nutrients and organic carbon quantified in soil indicates that the forest soil is high in organic carbon and available "K" and medium in phosphorus and nitrogen. The biomass, soil carbon and total carbon (soil C＋C in plant biomass) in the forest was 1,995.98, 75.83 and $973.65Mg\;ha^{-1}$. More than 90% of the carbon accumulated in the forest was contributed by the trees. The annual litter production of the forest was $5.37Mg\;ha^{-1}$. Carbon accumulation is intricately linked with site quality factors. The estimated biomass of $1,995.98Mg{\cdot}ha^{-1}$ clearly indicates this. The site quality factor i.e. tropical moist deciduous with optimum availability of soil nutrients, heavy precipitation, high mean monthly relative humidity and optimum temperature range supported luxuriant growth which was realized as higher biomass accumulation and hence higher carbon accumulated.

• 산학경영연구
• /
• 제22권1호
• /
• pp.103-123
• /
• 2009

2008년 9월 15일 Lehman Brothers의 파산이후 국제금융시장의 불확실성은 급격히 증대되었다. 각국의 금융시장 안정화 조치에도 불구하고 세계의 주식시장은 급락과 급등의 불안한 모습을 보였으며, 미국 금융시장의 불황으로 달러화에 대한 신뢰도가 급격히 하락하여 달러화는 주요 통화대비 약세로 전환되었다. 이와 관련 본 연구는 리먼사태 이후 발생한 글로벌 금융위기 발생이후 정책당국이 대응한 정책들에 대해 보도자료 등을 통해 분석을 하였으며 여러가지 시사점을 제공하였다. 하지만 이러한 의의에도 불구하고 본 연구는 여러가지 한계점을 가지고 있다. 따라서 한계점을 언급하고 이와 관련하여 앞으로의 연구방향을 제시하고자 한다.

• International Journal of Internet, Broadcasting and Communication
• /
• 제9권4호
• /
• pp.31-37
• /
• 2017

Recently Drone technology is emerging as an alternative new way of distribution systems services. Amazon, Google which are global network chain distribution companies are developing an idea of Drone based delivery service and applied for patent for Drone distribution systems in USA. In this paper, we investigate a way to adopt Drone system to Air Cargo logistics, in particular, drone system based on combination of Light ID and RFID technology in the management procedure in stock warehouse. Also we explain the expected impact of Drone systems to customs declaration process. In this paper, we address the investigated limitations of Drone by the Korean Aviation Act as well as suggest the directions of future research for application of Drone to Air logistics industry with investigated limitations.