• Proceedings of the KIEE Conference
• /
• 2001.07a
• /
• pp.550-552
• /
• 2001

The vertically integrated power industry was divided into six generation companies and one market operator, where electricity trading was launched at power exchange. In this environment, the profits of each generation companies are guaranteed according to utilization of their own generation equipments. Especially, the electricity demand shows seasonal and weekly regular pattern, which the some capacity should be provided into ancillary service based on the past demand forecasting error and operating results of electricity market. Namely, if generation cost function is applied to SMP and BLMP as announced the previous day, the available generation capacity of the following day could be optimally distributed, and therefore contract capacity of ancillary service applied to CBP(Cost Based Pool) and TWBP(Two-Way Bidding Pool) is determined. Consequently, it is Possible to use the retained equipments optimally. This paper represents on efficient bidding strategies for generation equipments through the calculation of the contract and the application of each generator cost function based on the past demand forecasting error and market operating data.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.41 no.4
• /
• pp.81-90
• /
• 2018

Modern investment theory has empirically proved that stock returns can be explained by several factors such as market risk, firm size, and book-to-market ratio. Other unknown factors affecting stock returns are also believed to still exist yet to be found. We believe that one of such factors is the operational efficiency of firms in transforming inputs to outputs, considering the fact that operations is a fundamental and primary function of any type of businesses. To support this belief, this study intends to empirically study the relationship between firm efficiency and stock price performance. Firm efficiency is measured using data envelopment analysis (DEA) with inputs and outputs obtained from financial statements. We employ cross-efficiency evaluation to enhance the discrimination power of DEA with a secondary objective function of aggressive formulation. Using the CAPM-based performance regression model, we test the performance of equally weighted portfolios of different sizes selected based upon DEA cross-efficiency scores along with a buy & hold trading strategy. For the empirical test, we collect financial data of domestic firms listed in KOSPI over the period of 2000~2016 from well-known financial databases. As a result, we find that the porfolios with highly efficient firms included outperform the benchmark market portfolio after controlling for the market risk, which indicates that firm efficiency plays a important role in explaining stock returns.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2020.06a
• /
• pp.202-203
• /
• 2020

Unlike price calculation by cost accounting, which categorizes costs into material costs, labor costs, and miscellaneous expenses to determine the construction budget price, construction cost calculation based on Construction Standard Unit Prices utilizes unit prices extracted from market prices of items from projects already completed to estimate costs of similar construction projects. Although unit price information is collected through construction site surveys to revise these construction standard unit prices every year, but due to the limitations of the site survey method, it is difficult to quickly implement the rapid changes in the construction methods and market prices. As such, an important issue that arose was the identification of work items whose prices need urgent revision. This study conducted research on factors that need to be considered when developing online survey system for monitoring construction site market prices. This study is expected to enhance convenience for users, and provide an efficient data collection and management system for administrators.

• International Journal of Aeronautical and Space Sciences
• /
• v.17 no.2
• /
• pp.268-283
• /
• 2016

Aircraft manufacturing companies have to consider multiple derivatives to satisfy various market requirements. They modify or extend an existing aircraft to meet new market demands while keeping the development time and cost to a minimum. Many researchers have studied the derivative design process, but these research efforts consider baseline and derivative designs together, while using the whole set of design variables. Therefore, an efficient process that can reduce cost and time for aircraft derivative design is needed. In this research, a more efficient design process is proposed which obtains global changes from local changes in aircraft design in order to develop aircraft derivatives efficiently. Sensitivity analysis was introduced to remove unnecessary design variables that have a low impact on the objective function. This prevented wasting computational effort and time on low priority variables for design requirements and objectives. Additionally, uncertainty from the fidelity of analysis tools was considered in design optimization to increase the probability of optimization results. The Reliability Based Design Optimization (RBDO) and Possibility Based Design Optimization (PBDO) methods were proposed to handle the uncertainty in aircraft conceptual design optimization. In this paper, Collaborative Optimization (CO) based framework with RBDO and PBDO was implemented to consider uncertainty. The proposed method was applied for civil jet aircraft derivative design that increases cruise range and the number of passengers. The proposed process provided deterministic design optimization, RBDO, and PBDO results for given requirements.

• Journal of Electrical Engineering and Technology
• /
• v.7 no.2
• /
• pp.141-150
• /
• 2012

The present study examines an efficient congestion management system compatible with the evolving environment. The key is to build an information model shared and exchanged for marketbased solutions to alleviate congestion. Traditional methods for congestion management can be classified into two categories, i.e., the centralized scheme and the decentralized scheme, depending on the extent to which the independent system operator (ISO) is involved in market participants' (MPs) activities. Although the centralized scheme is more appropriate for providing reliable system operation and relieving congestion in near real-time, the decentralized scheme is preferred for supporting efficient market operation. The minimum set of information between the ISO and MPs for decentralized scheme is identified: i) congestion-based zone, ii) Power Transfer Distribution Factors, and iii) transmission congestion cost. The mathematical modeling of the proposed information is expressed, considering its process of making effective use of information. Numerical analysis is conducted to demonstrate both cost minimization from the MP perspective and the reliability enhancement from the ISO perspective based on the proposed information exchange scheme.

• Journal of Distribution Science
• /
• v.7 no.1
• /
• pp.55-70
• /
• 2009

There is under restructuring of whole distribution market in Mokpo recently. Large-Scale Discount Stores such as E-mart, Lotte Mart, Homeplus and Nonghyup Hanaro Mart entered successfully in the distribution environment in Mokpo. However, the small and medium distributors are falling rapidly, and traditional market is depressed. This status gives some positive effects to make one-stop, good price, good quality and great variety of shopping for saving the time and effort through changing the customers' life-style. This change, however, made the traditional market worse that played as the core channel for trading the local special products and an important role for local economic in retailing market. It is a threatening factor for that traditional market to recover the recession. The decline of traditional market and the bankruptcy of small retailing dealers accelerate the stagnation of local economic and commercial power. Therefore, it need a systematic and synthetical study to solve the negative factors for improving life of the local resident. This paper looked into the concept, issues and development strategy of traditional market that affect local economic development directly. It studied the customers' awareness for traditional market that was recently modernized the facilities in Mokpo. Particularly, based on the research material that was published last academic symposium, it looked about the issues and development strategy that could happen in traditional market not the market of a specific region but all over the country. Therefore, the purpose of this paper is that the central and local government and retailers get a help to make the efficient and useful development strategy through analyzing the effects of customers for modernizing the facilities of traditional market.

• Proceedings of the KIEE Conference
• /
• 2009.07a
• /
• pp.1165_1166
• /
• 2009

In recent years, energy prices have soared, which of course have increased costs for railway operators. Simultaneously, the energy market has considerably changed that in most developed countries, it is deregulated, giving railway operators an opportunity to define new ways of using energy. Efficient operation of the railway system is considered as an essential way to energy saving while an efficient management of power level helps to lower the reference subscribed power, giving access to better energy rates. It is studied on the relation between time and force for the energy efficient driving of train in railway when the train is braking according to several slips.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.30 no.11 s.158
• /
• pp.1495-1506
• /
• 2006

The purposes of this study are to investigate the formation and the change of apparel retail structure historically with the viewpoint that the retail structure is affected by the process of economic development. This study was done by literature research method and the result of this study is the following. The tailor and seamstress shops, the first clothing shops in Korea, were replaced by ready-made shops, because mass production system which had developed with the industrialization of Korea increased the advantage of economy of scale compared to handicrafts individual one. After that, the production system of apparel industry had been efficient continuously, while retail system had not. The retailing of famous brand apparel conducted by exclusive franchise store caused supplier oriented markets where the opinion and the desire of consumers were not reflected. While the retailing of the unknown brand apparel handled by small retail stores were inefficient. As the apparel industry matured in 1990s, various types of new stores appeared such as specialty stores, discount stores, TV home shopping, internet shopping, outlet malls, and big fashion stores in Dongdeamoon. These new stores have features of seeking profits in mass merchandising. As these large retail stores grow, the apparel retail structure of Korea is changing from a fragmented market to a vertically integrated one. This change is shown by the decrease of stores per inhabitants. With the change of environment, the apparel retail system which has lagged behind comparatively is expected to develop into more efficient system based on the large capital investment which raise the advantage of economy of scale.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.6 no.8
• /
• pp.1200-1205
• /
• 2002

Construction of Private networks is becoming easier due to the openness of telecommunication market, rapidly developing telecommunication technology. The size of existing private networks is becoming huge which resulted in surplus of capacity of the networks. These trends will generate a problem of efficient use of national telecommunication resources and which will be a factor for the structure of domestic telecommunication market which will have a big impact on the existing telecommunication carriers. Therefore, national policy of private network issues should be considered along with the national efforts for the information infrastructure, control of telecommunication market, fairness of competition, strength Power of national competition. In this paper it will be suggested that the efficient policy on the issue of domestic private network, by analyzing present situation, status quo, laws, regulation and procedure for domestic private networks and comparing it with those of U.S.A, Japan, EU.

• Korean Journal of Construction Engineering and Management
• /
• v.6 no.6 s.28
• /
• pp.124-132
• /
• 2005

The efficient preservation and improvement of stock buildings including houses have become a significant national issue coming into the 21st century. The increase rate of new house demands have lessened and the efficient management and usage of old buildings have become more important. However, lacking research on the effects obtained through remodelling and the perception that it is less profitable than reconstruction have interfered with the vitalization of the market. Also, the excessive profit rate contractors insist have caused conflict between the residents and contractor and weakened market stability. This research examines the related codes, the strengths and weaknesses of marketing positioning in apartment remodelling a rational method for analyzing each project and the working process. A survey was performed to investigate preferences and priorities between the business methods in order to obtain advices that can smoothly progress each project and improve overall building quality. Through this study, the flow of remodeling market is elevated reaching the level in advanced nation.