• 한국경영과학회지
• /
• 제16권1호
• /
• pp.45-58
• /
• 1991

The importance of marketing mix variables, replacement demand, and competition in a new product growth model has been cited by many researchers. In this paper, these factors are integrated with an aim to model company sales of competing durables. Based on the most popular new product growth model, numerous extensions and incorporations of contributions from related research fields are tried. Model parameters are estimated by the Kalman filter. And, the proposed model is applied to the sales of four consumer durable goods. Empirical applications show the benefits, as well as the limitations of the proposed model.

• 국제학술발표논문집
• /
• The 3th International Conference on Construction Engineering and Project Management
• /
• pp.1015-1022
• /
• 2009

Currently, Korean real estate market has experienced cooling down of the business because of the global economic crisis which resulted from the subprime mortgage lending practice. In response, the Korean government has enforced various policies at the base of deregulating real estate speculation, such as increasing Loan to value ratio (LTV) in order to stimulate housing demand and supply. However, these policies seemed to result in deep confusion in the Korean housing market. Furthermore, analysis for housing market forecasting, especially international financial crisis on Korean real estate market, has been partial and fragmentary, therefore comprehensive solution and systematical approach is required to analyze the real estate and real estate financial market including causal nexus between market determining factors. In an integrated point of view, applying the system dynamics modeling, the paper aims at proposing Korean Real Estate and Mortgage market dynamics models based on fundamental principles of housing market determined by supply and demand. We also find the impact of deregulation policies focusing on mortgage loan which is the main factors of policies.

• 한국건설관리학회논문집
• /
• 제3권4호
• /
• pp.132-138
• /
• 2002

최근 건설시장의 선진화를 목적으로, 주어진 공기 내 완공 및 비용절감, 품질향상 등을 위하여 PMIS(사업관리정보시스템)의 활용이 심도 있게 요구되고 있다. 하지만, 현재 각 프로젝트에서 개발된 PMIS는 개발기간의 한시성으로 대개 공사현황위주로 되어 있고, 프로젝트 수행자들의 PMIS사용 역시 형식적으로 운용됨으로써, 발주자, 사업관리자, 시공자간의 효율적인 의사소통에 한계가 있는 실정이다. 이에 현재까지 개발된 사업관리정보시스템을 검토하고, 그동안 현업에서 개발한 경험을 토대로 효율적 인 PMIS의 구축방향을 제시코자 한다.

• Industrial Engineering and Management Systems
• /
• 제13권2호
• /
• pp.129-147
• /
• 2014

This study proposes an optimal operational policy for a green supply chain (GSC) where a retailer pays an incentive for collection of used products from customers and determines the optimal order quantity of a single product under uncertainty in product demand. A manufacturer produces the optimal order quantity of product using recyclable parts with acceptable quality levels and covers a part of the retailer's incentive from the recycled parts. Here, two scenarios for the product demand are assumed as: the distribution of product demand is known, and only both mean and variance are known. This paper develops mathematical models to find how order quantity, collection incentive of used products and lower limit of quality level for recycling affect the expected profits of each member and the whole supply chain under both a decentralized GSC (DGSC) and an integrated GSC (IGSC). The analysis numerically compares the results under DGSC with those under IGSC for each scenario of product demand. Also, the effect of the quality of the recyclable parts on the optimal decisions is shown. Moreover, supply chain coordination to shift the optimal decisions of IGSC is discussed based on: I) profit ratio, II) Nash bargaining solution, and III) Combination of (I) and (II).

• Ocean and Polar Research
• /
• 제29권2호
• /
• pp.155-165
• /
• 2007

Recently, coastal erosion has become an important issue in relation to keeping territorial integrity of a nation as well as protecting the coastal marine ecosystem. This study examines some apprehensions about the effectiveness of the existing legal system concerning prevention of coastal erosion. After examining several case studies in Scotland, the USA, and the Netherlands, this study proposes appropriate revisional legal measures that can be applied in Korea: first, the coastal management act should be revised for stronger, enforceable and practical legal grounds emphasizing minimal coastal erosion; second, the proposed "Comprehensive Coastal Erosion Prevention Plan" should be established and implemented in four steps such as characterization of issues through surveys of stakeholders and demand assessment, plan establishment, execution, and maintenance and management; third, there is a demand to establish and implement a legal framework to support monitoring activities which provide important data and information to prevent coastal erosion; fourth, the chronic region of damage is designated as the "Vulnerable Area" to be protected and managed accordingly; fifth, the "Coastal Coordination council" is established and operated for developing an integrated coastal management policy and visions for sustainable coastal zone, as well as coordinating and intervention of any activities which may cause coastal erosion.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2015년도 학술발표회
• /
• pp.216-216
• /
• 2015

Frequent hydro-meteorological events caused by global climate change and human exacerbate activities, make the water resource problem more complicated. The increasing speed urbanization brings a significant impact on the city flood control and security, water supply safety, water ecological security, water environment safety and the water engineering security in China, and puts forward higher requirements to urban water integrated management, undoubtedly which become the biggest obstacle for water ecological civilization construction, thus urgent requiring an advanced methods to enhance the effectiveness of the water integrated management. The other fields of smart ideas point out a development path for water resource development. The construction demand of smart water resource is expounded in the paper, combining the philosophy of modern Internet of things with the application of cloud computing technology. The concept of smart water resource is analyzed, the connotation characteristics of smart water resource is extracted, and the general model of smart water resource is refined. Then, the frame structure of smart water resource is put forward. The connotation and the overall framework of the smart water resource represent a higher level of water resource informationization development and provide a comprehensive scientific and technological support to transform water resource management from an extensive, passive, static, branch and traditional management to a fine, active, dynamic, collaborative and modern management.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2004년도 하계학술대회 논문집 A
• /
• pp.153-155
• /
• 2004

Various problems such as the increase of the power loss and the voltage instability may often occur in the case of low load power factor. The demand of reactive power increases continuously with the growth of active power and the restructuring of electric power companies makes the integrated management of ractive power a troublesome problem, so that the systematic control of load power factor is required. In this paper, the load power factor sensitivity of the generation cost is used for determining the locations of reactive power compensation devices effectively and for enhancing the load power factor appropriately. In addition, the integrated costs are used for determining the value of the load power factor from the point of view of the economic operation. It is shown through the application to a large-scale power system that the system power factor can be enhanced effectively and appropriately using the load power factor sensitivity and integrated costs.

• 한국습지학회지
• /
• 제13권3호
• /
• pp.593-602
• /
• 2011

지난 반세기 동안의 무분별한 개발로 인하여 하구역 생태 환경은 심각하게 훼손되었다. 이를 관리하기 위한 전 지구적 요구는 증대되고 있으나 효율적으로 관리할 수 있는 시스템은 부재한 실정이다. 따라서 본 연구에서는 기관별로 산재된 하구역 생태 환경 데이터를 통합하여 하구역을 효과적으로 관리할 수 있는 통합 DB관리시스템을 개발고자 하였다. 이를 위해 2010년 영산강 하구역을 대상으로 실시한 모니터링 DB와 공간 데이터 표출에 우수한 GIS DB를 통합하여 시스템 개발에 적용하였다. 시스템의 개발환경은 VisualBasic.NET과 지도기반의 공간 분석을 위한 ArcObjects 컴포넌트를 이용하였다. 또한 데이터의 활용을 높이기 위하여 사용자 요구분석을 통한 GUI(Graphical User Interface)의 구성, 모니터링 DB의 표출방안, 레이어의 우선순위, 모듈단위 기능 등을 정의하였고, 최종적으로 정의된 내용을 바탕으로 시스템을 개발하였다. 본 연구에서 개발된 통합 DB관리시스템은 영산강의 현 생태 환경을 파악할 수 있으며, 사용자에게 효율적인 공유 및 관리환경을 지원할 것으로 예측된다. 향후에는 모델링 시스템과 연계하여 미래 하구역 생태 환경의 종합적인 진단 및 신뢰성 있는 예측이 가능할 것으로 기대된다.

• 전기학회논문지P
• /
• 제67권2호
• /
• pp.112-118
• /
• 2018

In recent years, decentralized power have been increasing due to environmental problems, liberalization of electricity markets and technological developments. These changes have led to the evolution of power generation, transmission, and distribution into discrete sectors and the division of integrated power systems. Therefore, studies are underway to efficiently supply power and reduce losses to each sector's demand. This is a major concern for system planners and operators, as it accounts for a relatively high proportion of total power, with a transmission and distribution loss of 4-6%. Therefore, this paper analyzes the status of loss management based on the current transmission and distribution loss rate of each country and transmission loss management cases of each national power company, and proposes a loss rate prediction algorithm according to the long-term transmission system plan. The proposed algorithm predicts the demand-based long-term evolution and the loss rate of the grid to which the transmission plan is applied.

• Industrial Engineering and Management Systems
• /
• 제14권2호
• /
• pp.129-158
• /
• 2015

It is necessary for retailers to determine the optimal ordering policy of products considering supply disruptions due to a natural disaster and a production process failure as quality and machine breakdowns. Under the situation, a dualsourcing supply chain (DSSC) is one of effective SC for retailers to order products reliably. This paper proposes the optimal ordering policy of a product in a DSSC with a retailer and two manufacturers. Two manufacturers may face supply disruptions due to a natural disater and a production process failure after they received the retailer's order of products. Here, two scenarios of demand information of products are assumed: (i) the demand distribution is known (ii) mean and variance of the demand are known. Under above situations, two types of DSSC are discussed. Under a decentralized DSSC (DSC), a retailer determines the optimal ordering policy to maximize his/her total expected profit. Under the integrated DSSC (ISC), the optimal ordering policy is determined to maximize the whole system's total expected profit. Numerical analysis investigates how demand information and supply disruptions affect the optimal decisions under DSC and ISC. Besides, profitability of supply chain coordination adjusting the wholesale price is evaluated to encourage the optimal decision under ISC.