• Title/Summary/Keyword: Robust decision making

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Applicability of Robust Decision Making for a Water Supply Planning under Climate Change Uncertainty (기후변화 불확실성하의 용수공급계획을 위한 로버스트 의사결정의 적용)

  • Kang, Noel;Kim, Young-Oh;Jung, Eun-Sung;Park, Junehyeong
    • Journal of Climate Change Research
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    • v.4 no.1
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    • pp.11-26
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    • 2013
  • This study examined the applicability of robust decision making (RDM) over standard decision making (SDM) by comparing each result of water supply planning under climate change uncertainties for a Korean dam case. RDM determines the rank of alternatives using the regret criterion which derives less fluctuating alternatives under the risk level regardless of scenarios. RDM and SDM methods were applied to assess hypothetic scenarios of water supply planning for the Andong dam and Imha dam basins. After generating various climate change scenarios and six assumed alternatives, the rank of alternatives was estimated by RDM and SDM respectively. As a result, the average difference in the rank of alternatives between RDM and SDM methods is 0.33~1.33 even though the same scenarios and alternatives were used to be ranked by both of RDM and SDM. This study has significance in terms of an attempt to assess a new approach to decision making for responding to climate change uncertainties in Korea. The effectiveness of RDM under more various conditions should be verified in the future.

Optimization of Sheet Metal Forming Process by using Decision-Making Theory (의사결정이론을 이용한 박판성형공정의 최적화)

  • Kim, Kyung-Mo;Yin, Jeong-Je
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.11 no.2
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    • pp.125-136
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    • 2012
  • Wrinkle and fracture are two major defects frequently found in the sheet metal forming process. In this process there are more than one design attributes to optimize and several uncontrollable factors which cannot be ignored in determining the optimal values of design variables. Therefore, attempts to reduce defects through a traditional optimization technique are often led to failures. In this research, a new design method for reducing the wrinkle and fracture under uncontrollable factors is presented by using decision-making theory. To avoid the psychological difficulties in determining the scaling constants of the multi-attribute utility function by using the ordinary lottery questions, a pair-wise comparison procedure is adapted to avoid this problem. The effectiveness of the proposed method is illustrated through a robust design of sheet metal forming process of a side member of an automotive body.

Re-evaluation of comprehensive flood management plan for the Yeongsan river basin using Robust Decision Making (로버스트 의사결정을 이용한 영산강유역 종합치수계획 재평가)

  • Kang, Dong-Heon;Kim, Young-Oh;Park, Junehyeong
    • Journal of Korea Water Resources Association
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    • v.50 no.2
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    • pp.99-109
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    • 2017
  • This research adopted a Robust Decision Making framework to re-evaluate four alternative strategies proposed by the Comprehensive Flood Management Plan for the Yeongsan River Basin report (MLTM, 2005) considering uncertainties of future floods under condition of climate change. To reflect the uncertainties, multiple sets of future flood scenarios were used with three uncertainty factors: the change in rainfall intensity based on the RCP climate change scenarios and the changes in the temporal and the spatial flood distributions. With combinations of these factors, 216 plausible flood scenario sets were generated and the performances of the four alternatives under different future states were evaluated. From the results, the most robust alternative among the strategies was identified. Moreover, the key factors which made the tested alternatives poor were discovered through assessment of the uncertainty factors. This information can provide detailed insights to decision makers and can be utilized to overcome alternatives' potential vulnerabilities by modifying the strategy to be more robust.

Decision making for coping with climate change uncertainty in water resources planning: Robust Decision Making (기후변화 불확실성에 대응하는 수자원계획 의사결정: Robust Decision Making)

  • Kang, No-El;Jung, Eun-Sung;Kim, Young-Oh;Park, June-Hyung
    • Proceedings of the Korea Water Resources Association Conference
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    • 2012.05a
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    • pp.94-94
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    • 2012
  • 기후변화 대응은 온실가스 배출의 감축 및 흡수원을 확대하는 완화(mitigation)와 기후변화로 인한 영향과 취약성을 평가하여 피해를 최소화하는 적응(adaptation)이 상호 균형을 이루어야 한다. 지금까지 우리나라를 포함한 국제사회는 대부분 완화를 위해 노력해 왔지만 최근에 들어 완화만으로는 기후변화의 영향을 회피하기 어렵다는 사실이 인식되면서 적응 연구가 다양하게 이루어지고 있다. 이러한 상황 가운데 적응 계획의 실현화를 위해서 기후변화의 불확실성을 고려한 의사 결정에 관한 연구가 반드시 뒷받침 되어야 한다. 기존의 일반적인 의사결정은 다양한 미래 시나리오들 하에 가장 높은 효용을 가져오는 최적(Optimal)의 대안을 채택하는 고전적 결정분석(Classical Decision Analysis)의 프레임을 사용하였다. 그러나 기후변화로 인해 미래 기후 예측 시나리오의 불확실성이 증대되면서 최근에는 최적의 대안을 선정하는 것에 대한 의문이 제기되며 새로운 기법에 대한 연구가 이루어지고 있다. 본 연구는 기후변화의 불확실성을 고려하기 위한 새로운 의사결정 기법인 로버스트 의사결정(Robust Decision Making, RDM)을 실제유역의 적용을 통해 제안하고자 한다. 로버스트 의사결정은 RAND에서 개발한 것으로 최적의 대안을 채택하는 것 대신 모든 가능한 시나리오 가운데 가장 안정적인 전략을 채택한다는 것에서 기존의 의사결정 체계와 차이가 있다. 연구의 적용은 안동-임하댐 유역을 대상으로 온실 가스 배출 시나리오 A1B, A2, B1시나리오에 대해 15개의 GCMs에서 산출된 기후자료를 기반으로 기후변화의 시나리오를 작성하였으며, 다양한 측면의 대안을 설정하여 용수공급량을 평가하였다. 연구의 결과로 산정될 각 대안 별 안정적인 정도와 취약한 시나리오에 대한 정보는 기후변화의 불확실성을 전제한 의사결정을 할 때 로버스트 의사결정이 갖는 장점이 될 수 있다.

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Deriving Robust Reservoir Operation Policy under Changing Climate: Use of Robust Optimiziation with Stochastic Dynamic Programming

  • Kim, Gi Joo;Kim, Young-Oh
    • Proceedings of the Korea Water Resources Association Conference
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    • 2020.06a
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    • pp.171-171
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    • 2020
  • Decision making strategies should consider both adaptiveness and robustness in order to deal with two main characteristics of climate change: non-stationarity and deep uncertainty. Especially, robust strategies are different from traditional optimal strategies in the sense that they are satisfactory over a wider range of uncertainty and may act as a key when confronting climate change. In this study, a new framework named Robust Stochastic Dynamic Programming (R-SDP) is proposed, which couples previously developed robust optimization (RO) into the objective function and constraint of SDP. Two main approaches of RO, feasibility robustness and solution robustness, are considered in the optimization algorithm and consequently, three models to be tested are developed: conventional-SDP (CSDP), R-SDP-Feasibility (RSDP-F), and R-SDP-Solution (RSDP-S). The developed models were used to derive optimal monthly release rules in a single reservoir, and multiple simulations of the derived monthly policy under inflow scenarios with varying mean and standard deviations are undergone. Simulation results were then evaluated with a wide range of evaluation metrics from reliability, resiliency, vulnerability to additional robustness measures. Evaluation results were finally visualized with advanced visualization tools that are used in multi-objective robust decision making (MORDM) framework. As a result, RSDP-F and RSDP-S models yielded more risk averse, or conservative, results than the CSDP model, and a trade-off relationship between traditional and robustness metrics was discovered.

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Development and Application of Robust Decision Making Technique Considering Uncertainty of Climatic Change Scenarios (기후변화 시나리오의 불확실성을 고려하기위한 로버스트 의사결정 기법의 개발 및 적용)

  • Jun, Sang-Mook;Chung, Eun-Sung;Lee, Sang-Ho;Kim, Yeonjoo
    • Journal of Korea Water Resources Association
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    • v.46 no.9
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    • pp.897-907
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    • 2013
  • Climate change is expected to worsen the depletion of streamflow in urban watershed. In this study, we therefore considered the treated wastewater (TWW) use as an adaptation strategy and devised a framework to identify prioritized areas for TWW use. An integrated framework that includes hydrological factors as well as social and environmental components were employed to determine the criteria for decision making. Fuzzy theory was employed to consider the uncertainties in the climate change scenarios and the weights of the performance value. All alternatives were evaluated using the fuzzy TOPSIS method. In addition, statistical method and decision making methods under complete uncertainty were used for robust decision making. As a result, ranking the alternatives using the fuzzy TOPSIS method and robust approach such as maximin, maximax, Hurwicz and equal likelihood criterion mitigated the level of uncertainty and ambiguity in each alternative. The finding of this study can be helpful in prioritizing water resource management projects considering various climate change scenarios.

Application of Fuzzy Multi-criteria Decision Making Techniques for Robust Prioritization (로버스트 우선순위 결정을 위한 Fuzzy 다기준 의사결정기법의 적용)

  • Han, Bong Gu;Chung, Eun Sung
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.33 no.3
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    • pp.917-926
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    • 2013
  • This study presents the feasibility of fuzzy multi-criteria decision making (MCDM) techniques for the robust prioritization of projects. It is applied to water resources planning problem. Results from weighted sum method (WSM), analytic hierarchy process (AHP), revised analytic hierarchy process (R-AHP), and TOPSIS are compared with those from Fuzzy WSM, Fuzzy, AHP, Fuzzy R-AHP, and Fuzzy TOPSIS. For the calculation, all weights on criteria and the normalized data were obtained from the same investigation. As a result, the rankings from four MCDM techniques are slightly different while those from fuzzy MCDM show the comparatively consistent ranking. Therefore, it is desirable to use fuzzy MCDM technique when MCDM is used for the prioritization problem, since fuzzy MCDM can include the uncertain variability of input data and weighting values on criteria.

A New Product Development Using Robust Design and Decision Making Process

  • Lin, Than;Doan, Trieu An;Vu, Ngoc Anh;Cho, Guk-Hyun;Lee, Jae-Woo;Byun, Yung-Hwan
    • Journal of the Korean Society of Systems Engineering
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    • v.3 no.1
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    • pp.41-48
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    • 2007
  • This paper presents a design methodology for developing a new push scooter. A case study is clone with effective planning processes to ensure the product quality under the different phases of a product design process. Parametric model based design process simulation and optimization is implemented by using ANSYS application tool. The relationship matrix and decision matrix are drawn by using several methods. The simulation results for deterministic design and robust design are compared. This entire design process phase can support the design and quality improvements for a new product development.

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Application of Analytic Hierarchy Process of Defense Innovation 2020 Advanced Topics in Plan Step of Defense Planning Management Afftair (국방기획 관리업무의 기획단계에서 국방개혁 2020 추진과제들에 대한 계층분석적 의사결정 적용)

  • Choi, Myoung-Seo;Lee, Hong-Chul;Cheon, Hyeon-Jae
    • Journal of the military operations research society of Korea
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    • v.32 no.2
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    • pp.212-222
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    • 2006
  • The defense innovation 2020 advanced topics which have to establish robust milatary are based on archiving defense innovation by selecting twenty-one main topics and eighties' sub-topics whose topics focus on defense innovation and defense circumstance in 2020. Although defense innovation 2020 which is to be advanced with defense basic policy need to decision making, it is specified in programming step by merging budget with plan. If the Defense Ministry archives decision making from initial plan step, although it archives group decision making in programming step at present, it will archive efficient affair. This study archives a group decision making of defense innovation 2020 advanced topics which were published in the Defense Ministry by applying Analytic Hierarchy Process in plan step. In addition, if the weights of the main topics are equal, the sub topics analyze how to be changed throughout sensitivity analysis and suggest the topics' priority rank throughout group decision making.

Web-Based Organizational Memory Acquisition by Using a Fuzzy Cognitive Map (퍼지인식도를 이용한 웹기반 조직지식획득에 관한 연구)

  • 이건창
    • Journal of Intelligence and Information Systems
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    • v.5 no.2
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    • pp.79-97
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    • 1999
  • Knowledge management (KM) is emerging as a robust management mechanism with which an organization can remain highly intelligent and competitive in a turbulent market. Organization knowledge is at the heart of KM success. As a vehicle of acquiring organizational knowledge in a distributed decision-making environment, we applied a fuzzy cognitive map (FMM) technique and proved its effectiveness in a distributed knowledge management environment. Our approach was applied to the financial statement analysis problem, yielding a robust result.

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