• 제어로봇시스템학회논문지
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• 제4권6호
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• pp.802-810
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• 1998

The purpose of this study is to find the analytic solution of determining the optimal capacity of processes and storages to meet the product demand. Recent trend to reduce product delivery time and to provide high quality product to customer requires the increasing capacity of storage facilities. However, the cost of constructing and operating storage facilities is becoming substantial because of increasing land value, environmental and safety concern. Therefore, reasonable decision making about the capacity of processes and storages is important subject for industries. The industrial solution for this subject is to use the classical economic lot sizing method, EOQ(Economic Order Quantity) model, trimmed with practical experience but the unrealistic assumption of EOQ model is not suitable for the chemical plant design with highly interlinked processes and storages. This study, a first systematic attempt for this subject, clearly overcomes the limitation of classical lot sizing method. The superstructure of the plant consists of the network of serially and/or parallelly interlinked processes and storages. A novel production and inventory analysis method, PSW(Periodic Square Wave) model, is applied. The objective function of optimization is minimizing the total cost composed of setup and inventory holding cost. The advantage of PSW model comes from the fact that the model provide a set of simple analytic solution in spite of realistic description of material flow between process and storage. The resulting simple analytic solution can greatly enhance the proper and quick investment decision for the preliminary plant design confronting diverse economic situation.

• 한국환경복원기술학회지
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• 제21권1호
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• pp.31-40
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• 2018

Since the Millennium Ecosystem Assessment Report was published in 2005, the conflict between development and the preservation of the ecological environment has turned to paying attention to value assessments in rational decision-making. In recent years, the concept of ecosystem services has been recognized as a viable one for making significant decisions. However, a trade-off between increase and decrease occurs between the ecosystem services sub-categories (cultural service, regulating service, supporting service, and provisioning service), for which research centering on target sites is needed. To this end, the present study aims to investigate the trade-off relationship between service categories to search for reasonable decision-making strategies. As the research method, a survey was conducted using the translated version of SoIVES(Social Value for Ecosystem Services) 3.0 questionnaire of the United States Geological Survey. The research findings demonstrate the economic value, based on the derived monetary value of each service category, the economic value of the target site was compared among landscape aesthetic value 8,050,000 won, recreation value 6,750,000 won, biodiversity value 4,610,000 won, healing value 3,970,000 won, life-sustaining value 2,090,000 won, and productive value 220,000 won. And then the primarily recognized value criteria of the Tancheon ecosystem services illustrate landscape aesthetic and recreation value. Besides, this study illustrates visualized trade-off relationships based on user perception, and the derived relations illustrate the trade-off relationship between the cultural service, regulating service, supporting service, and provisioning service, as well as relationships between the components of the sub-categories.

• 한국통신학회논문지
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• 제18권6호
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• pp.824-834
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• 1993

주파수 이용 효율을 극대화하기 위한 셀룰러 이동 통신 시스템에서는 셀의 반경이 작아지면 이동국이 한 셀내에 잔류하는 시간이 짧아지고, 많은 핸드오버가 발생할 수 있게 된다. 또한 핸드오버 결정에 사용되는 수신 신호 전계 강도와 비트 에러율, 기지국과 이동국과의 거리 등의 파라미터는 부정확하게 측정되고 단일 파라메터에 의해 핸드오버 결정은 불충분하기 때문에, 측정치들을 함께 고려하여 핸드오버 결정을 강인하고 유연하게 할 수 있는 알고리즘을 필요로 한다. 본 논문에서는 퍼지 이론을 이용한 다기준(multi-criteria) 의사 결정 문제로 부정확한 다수의 파라미터를 이용하는 핸드오버 알고리즘을 제안하였는데 모의 실험 결과에 따르면 이 알고리즘을 쓸 경우 전체적인 의사 결정이 신뢰성이 있으며 유연하게 되었다. 제안된 알고리즘은 호 중단율, 핸드오버 요청율등의 평가 파라미터를 이용하여 전계 강도만을 이용하는 방법들과 비교되었다.

• 산경연구논집
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• 제6권2호
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• pp.5-11
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• 2015

Purpose - This research investigates the effect of disclosure quality with two main components, reliability and timeliness, on economic value added in Iran. Research design, data, and methodology - The sampling includes 170 Tehran Stock Exchange listed companies from 2008-12. Multiple regression analysis was applied to test the hypotheses and estimates of the coefficients. Firm size and return on assets were the control variables. Results - The results show that timeliness of information has a positive impact on economic value added. We did not find any significant relationship between disclosure quality and reliability of information and economic value added. The regressed model shows that there is no significant association between firm size and economic value added. The results also show that there is a positive association between return on assets and economic value added. Conclusions - Theoretically, timely information is effective in decision-making. This study shows that timeliness of information has positive effect on the creation of economic value added. However, disclosure quality, reliability, and firm size do not effect on economic value added. Companies with greater return on assets produce greater economic value added.

• 한국건설관리학회논문집
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• 제5권1호
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• pp.71-79
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• 2004

도심 재개발 사업의 타당성 분석단계에서 물리적, 환경적 요인들의 파악과 변화예측은 사업의 계속수행 여부를 결정하는데 중요한 영향을 미친다. 그러나 사업특성요인, 건설환경의 변화, 수요예측 등에 대한 정형화된 분석체계가 부재하여 실제 사업 타당성 분석 시 계량화된 방법보다 경험 및 직관에 의해 의사결정이 이루어지는 경우가 빈번하다. 또한, 사업에 커다란 영향을 미치는 많은 요인이 있음에도 불구하고 단순히 경제적인 측면만을 고려한 타당성 분석이 이루어져 궁극적으로 상당한 손실을 초래하는 사업으로 추진되는 경우가 빈번하다. 이에 대한 주된 원인은 도심 재개발 사업의 특성을 반영한 타당성 분석 절차 및 의사결정 방법에 관한 연구가 체계적으로 이루어지지 못했기 때문으로 분석된다. 본 연구는 도심 재개발 사업의 초기 단계에서 고려하여야 할 다양한 영향요인과 연계하여 체계적인 타당성 분석 절차 및 의사결정 방법을 제안하는 것을 목적으로 한다. 개선방안의 체계적인 진행을 위해 이론고찰, 사례연구, 설문분석, 전문가 면담 등을 통한 분석목표 및 절차, 관련요인, 의사결정방법 등에 대한 연구를 실시하였다. 제안된 도심 재개발 사업의 타당성 분석 절차 및 의사결정 방법은 사례연구에서 나타난 분석 절차의 문제점을 개선하는데 유용하게 활용될 것으로 기대된다. 특히, 단계별 분석목표를 설정하고 이와 관련된 요인의 분석과 합리적인 의사결정으로 도심재개발 사업의 타당성 분석능력을 향상시킬 수 있을 것이다.

• Journal of Information Technology Applications and Management
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• 제15권3호
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• pp.195-208
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• 2008

In an emergency management case, evaluating the economic value of information technology investments is a challenging problem due to the effects of decision making, uncertainty of disasters, and difficulty of measurements. Risk assessment and recovery process, one of the major functions in emergency management, consists of (1) measurement of damages or losses, (2) recovery planning, (3) reporting and approving budgets, (4) auctioning off recovery projects to constructors, and (5) construction for the recovery. Specifically and of our interest, measurement of damages or losses is often a costly and time-consuming process because the wide range of field surveys should be performed by a limited pool of trained agents. Managers, therefore, have to balance accuracy of the field survey against the total time to complete the survey. Using information technologies to support field survey and reporting has great potential to reduce errors and lowers the cost of the process. However, existing cost benefit analysis framework may be problematic to evaluate and justify the IT investment because the cost benefit analysis often include the long-run benefit of IT that is difficult to quantify and overlook the impact of managerial control upon the investment outcomes. Therefore, we present an alternative cost-centric control model that conservatively quantifies all cost savings to replace benefits in cost benefit analysis and incorporate the managerial control. The model provides a framework to examine how managerial decision making and uncertainty of disaster affect the economic value of IT investments. The current project in Emergency Agency in South Korea is introduced as a case to apply the cost-centric control model. Our work helps managers to better evaluate and justify IT-related investment alternatives in emergency management.

• 농업과학연구
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• 제25권2호
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• pp.293-309
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• 1998

This study is aimed at identifying the decision making criteria as B/C ratio, IRR and NPV based on the expected benefits and costs of the land utilization and promotion projects which have implemented to improve agricultural structure under WTO system. To carry out the objectives of the study, Sinseok project area located at Dangjin district, Chungnam province was selected. Sinseok project area has 306.2 ha of paddy area with 172 farm households. The project area will be operated by the 33 specialized farm households after completion of the project which will have 20 years of economic life. After completion of the project, farm size will be increased from 1.8ha to 9.3ha. Land intensity of the project area will be increased by 10%. Increase of land productivity and cost saving due to the labor saving technology as farm mechanization will be expected. According to the survey results, the annual amount of production cost savings per farm was estimated 3.884million won and increased total farm income was expected about 43.8million won per year. The total expexted project benefits was expected 174million won per year. The project costs to promote land utilization and structural change consisted of handling charges, and direct payment for land movility. The decision making criteria representing economic feasibility of the project such as B/C ratio, NPV and IRR were estimated 2.49, 483million won and 30% respectively when the cut-off rate was taken into account 10%. In conclusion, the land utilization and promotion project proppeled by the Korean Government under the agricultural land law is considered economically feasible from the view points of expected project benefits and costs. Accordingly the project have to be implemented more strongly under the G't financial support considering WTO and UR negociation which were aimed at achieving the free trade and improvement of international competitiveness of farm products.

• 가정과삶의질연구
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• 제20권6호
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• pp.151-162
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• 2002

The instability in the current financial market caused consumers a lot of difficulties in their financial decision making. The purpose of this study is to classify the changes in household portfolios during the economic crisis under IMF-trusteeship (IMF Crisis hereafter), and to examine the characteristics of the households according to the types of household portfolio changes. The data were taken from 1996 and 1999 Korean Household Panel Studies, and 1,293 households were selected for the final analysis. Methods of analysis included frequencies, percentages, Chi-square tests, F-tests, and t-tests. Major findings are as follows: 1. In the midst of the financial market changes during the period of the IMF crisis, consumers tended to manage their household portfolio differently according to their household characteristics. 2. The changes of household portfolio can be classified into two different types: the changed type (44.4%) and the unchanged type(55.6%). There are significant differences in the level of wealth, family life cycle stage, housing tenure, and the household head's job, between the changed type and the unchanged type. The family members of the unchanged type are more likely to be older and relatively wealthy compared with the families in the changed type. 3. The changes of household portfolio can be further classified into six different types: the unchanged-liquidity type (21%), the unchanged-multiplication type (24.6%), the unchanged-insurance type (9.8%), the changed-to-liquidity type (13.9%), the changed-to-multiplication type (13.0%), and the changed-to-insurance type (17.5%). There are significant differences in income level, wealth level, family life cycle stage, housing tenure, and the job of household head among the six types of changes.

• 대한안전경영과학회지
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• 제5권2호
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• pp.175-185
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• 2003

Information systems(IS) outsourcing has become a very important management strategy of implementing IS and many studies on the IS outsourcing approach had been performed in the organizations. But it isn't still show how to out source the IS functions and how to offer quantitative magnitude for judgement. To offer a quantitative decision model that can help practitioners set priority and reap the most benefits from outsourcing, we show outsourcing structure including 3 factors (strategic, economic and technological benefit) and sub-levels which is different from the Yang and Huang's model. Also, we compute the weight of alternatives using analytic hierarchy process to find a priority of the IS outsourcing. As a result of analysis, we suggest systematic steps and quantitative model to increase the precision of decision making. 1)

• 설비공학논문집
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• 제14권2호
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• pp.134-142
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• 2002

LCC (Life-Cycle Cost) analysis is a practical method and a guideline for evalua-ting the economic performance of building service systems. By using the LCC analysis, the most cost-effective design decision can be made, which has the lowest LCC during the project study period among the various design alternatives. The present case shows an example of appro-priate use of the LCC analysis, by demonstrating the procedures of decision making among at-tarnative building HVAC systems at community center and congress hall of a local government.