• 제목/요약/키워드: fuzzy risk

검색결과 236건 처리시간 0.029초

상이한 제원특성을 가진 빗물펌프장에서의 퍼지제어모형 적용 (An Application of Fuzzy Control Models to Inland Drainage Pumping Stations with Different Characteristics for Protection of Inland Flooding)

  • 심재현;이원환;조원철
    • 대한토목학회논문집
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    • 제13권3호
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    • pp.107-118
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    • 1993
  • 계속되는 도시화로 불투수성 면적이 증가되고, 환경변화에 의해 강우량이 증대되어 도시 저지대의 침수 우려가 더욱 가중되고 있는 실정이다. 따라서 서울특별시에서는 많은 예산을 들여 내수를 외수 쪽으로 강제배수시키는 빗물펌프장을 계속해서 보강 및 신설하고 있다. 그러나 상대적으로 경제적이라 할 수 있는 기존 빗물펌프장 시설의 적정 제어기법에 대한 연구나 투자는 전무한 상태라 할 수 있다. 본 연구는 퍼지제어기법을 적용하여 기존의 시설을 충분히 활용할 수 있는 기법을 개방하여 서울특별시 관내의 서로 다른 제원특성을 가진 57개의 유수지와 빗물펌프장에 적용하였다. 연구결과 현재의 펌프가동기준인 수위기준에 의한 펌프제어에 비하여 본 연구에서 적용한 퍼지제어기법이 전체 대상지점에 대하여 내수위를 같은 조건하에서도 충분히 낮출 수 있는 것으로 나타나 치수방재면에서 우수한 것으로 밝혀졌다.

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Technological and economic study of ship recycling in Egypt

  • Welaya, Yousri M.A.;Abdel Naby, Maged M.;Tadros, Mina Y.
    • International Journal of Naval Architecture and Ocean Engineering
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    • 제4권4호
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    • pp.362-373
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    • 2012
  • The ship recycling industry is growing rapidly. It is estimated that the International Maritime Organization's (IMO) decision to phase-out single hull tankers by 2015 will result in hundreds of ships requiring disposal. At present, the ship recycling industry is predominantly based in South Asia. Due to the bad practice of current scrapping procedure, the paper will highlight the harm occurring to health, safety and environment. The efforts of the Marine Environment Protection Committee (MEPC) which led to the signing of the Hong Kong International Convention are also reviewed. The criteria and standards required to reduce the risk and damage to the environment are discussed and a proposed plan for the safe scrapping of ships is then presented. A technological and economic study for the ship recycling in Egypt is carried out as a case study. This includes the ship recycling facility size and layout. The equipment and staff required to operate the facility are also evaluated. A cost analysis is then carried out. This includes site development, human resources, machineries and equipment. A fuzzy logic approach is used to assess the benefits of the ship breaking yard. The use of the fuzzy logic approach is found suitable to make decisions for the ship breaking industry. Based on given constraints, the proposed model has proved capable of assessing the profit and the internal rate of return.

만타형 UUV의 심도제어와 충돌회피에 관한 연구 (A Study of the Depth Control System and the Collision Avoidance System for the Manta-type UUV)

  • 김주한;이승건;이상의;배철한
    • 한국항해항만학회지
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    • 제32권6호
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    • pp.447-452
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    • 2008
  • 본 연구에서는 만타형 수중운동체의 수평 및 수직 방향에 대한 자동제어 및 충돌회피 시스템을 확립하였다. PID 제어이론, 퍼지 추론 등이 적용되었으며, 시뮬레이션에 사용된 6자유도 운동 방정식은 이론계산과 구속모형 시험에 의하여 확립하였다. PID제어에 의한 심도제어 결과가 제시되었으며, UUV의 충돌 위험도는 가상 소나 시스템을 이용한 퍼지 추론으로 추정하였다. 이를 이용하여 만타형 수중운동체의 심도제어 시스템 및 충돌회피 시뮬레이션 시스템이 개발되었다.

Evaluation Factors Influencing Construction Price Index in Fuzzy Uncertainty Environment

  • NGUYEN, Phong Thanh;HUYNH, Vy Dang Bich;NGUYEN, Quyen Le Hoang Thuy To
    • The Journal of Asian Finance, Economics and Business
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    • 제8권2호
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    • pp.195-200
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    • 2021
  • In recent years, Vietnam's economic growth rate has been attributed to the growth of many well-managed industries within Southeast Asia. Among them is the civil construction industry. Construction projects typically take a long time to complete and require a huge budget. Many socio-economic variables and factors affect total construction project costs due to market fluctuations. In recent years, crucial socioeconomic development indicators of construction reached a fairly high growth rate. Also, most infrastructure and construction projects have a high degree of complexity and uncertainty. This makes it challenging to predict the accurate project price. These challenges raise the need to recognize significant factors that influence the construction price index of civil buildings in Vietnam, both micro and macro. Therefore, this paper presents critical factors that affect the construction price index using the fuzzy extent analysis process in an uncertain environment. This proposed quantitative model is expected to reflect the uncertainty in the process of evaluating and ranking the influencing factors of the construction price index in Vietnam. The research results would also allow project stakeholders to be more informed of the factors affecting the construction price index in the context of Vietnam's civil construction industry. They also enable construction contractors to estimate project costs and bid rates better, enhancing their project and risk management performance.

An improved fuzzy c-means method based on multivariate skew-normal distribution for brain MR image segmentation

  • Guiyuan Zhu;Shengyang Liao;Tianming Zhan;Yunjie Chen
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제18권8호
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    • pp.2082-2102
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    • 2024
  • Accurate segmentation of magnetic resonance (MR) images is crucial for providing doctors with effective quantitative information for diagnosis. However, the presence of weak boundaries, intensity inhomogeneity, and noise in the images poses challenges for segmentation models to achieve optimal results. While deep learning models can offer relatively accurate results, the scarcity of labeled medical imaging data increases the risk of overfitting. To tackle this issue, this paper proposes a novel fuzzy c-means (FCM) model that integrates a deep learning approach. To address the limited accuracy of traditional FCM models, which employ Euclidean distance as a distance measure, we introduce a measurement function based on the skewed normal distribution. This function enables us to capture more precise information about the distribution of the image. Additionally, we construct a regularization term based on the Kullback-Leibler (KL) divergence of high-confidence deep learning results. This regularization term helps enhance the final segmentation accuracy of the model. Moreover, we incorporate orthogonal basis functions to estimate the bias field and integrate it into the improved FCM method. This integration allows our method to simultaneously segment the image and estimate the bias field. The experimental results on both simulated and real brain MR images demonstrate the robustness of our method, highlighting its superiority over other advanced segmentation algorithms.

자동생산체계에서 인간-기계 시스템의 안전도측정과 안전작업설계에 관한 연구 (A Study on Safety Assessment and Design of the Safe Task in Automated Man-Machine System)

  • 오영진
    • 산업경영시스템학회지
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    • 제13권22호
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    • pp.71-78
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    • 1990
  • Some problems to assess the safety of automated man-machine system are studied in many ways. The difficulty occurred in this system is the vagueness of human behavior. Fuzzy set theory is used to assess the human behavior in safety analysis. The unsafe behavior listed top 10 in accident statistics would be explained as the factors of human vagueness. Three cases are considered, which consist of man-machine system as man-man, man-machine, machine-machine types. For the design of safe task, using characteristics of work performance, each motion cycle time is required to know the rate of learning. Approach of human behavior to the standard motion means more safe motion. It is important to design the works as to minimize the time performance to the standard motion's, which utilize the control of risk potential with easy. In that process, use of fuzzy set theory is appropriate to analyze the human behavior to identify its vagueness.

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퍼지이론을 이용한 전문가 의견 도출법과 FMECA 전문가시스템 (Expert Opinion Elicitation and Expert System for FMECA using Fuzzy Theory)

  • 김동진;변융태;김형철;김진오
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2008년도 제39회 하계학술대회
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    • pp.261-262
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    • 2008
  • Failure Mode Effects and Criticality Analysis (FMECA) evaluates criticality and severity of each failure mode. Generally, those indices are determined subjectively by experts and operators. However, this process has no choice but to include uncertainty. In this paper, a method for eliciting expert opinions considering its uncertainty is proposed to evaluate the criticality and severity. In addition, a fuzzy expert system is constructed to determine the crisp value of risk level for each failure mode. The results are worth considering while deciding the proper policies for each component of the system.

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Risk Assessment and Decision-Making of a Listed Enterprise's L/C Settlement Based on Fuzzy Probability and Bayesian Game Theory

  • Cheng, Zhang;Huang, Nanni
    • Journal of Information Processing Systems
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    • 제16권2호
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    • pp.318-328
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    • 2020
  • Letter of Credit (L/C) is currently a very popular international settlement method frequently used in international trade processes amongst countries around the globe. Compared with other international settlement methods, however, L/C has some obvious shortcomings. Firstly, it is not easy to use due to the sophisticated processes its usage involves. Secondly, it is sometimes accompanied by a few risks and some uncertainty. Thus, highly efficient methods need to be used to assess and control these risks. To begin with, FAHP and KMV methods are used to resolve the problem of incomplete information associated with L/C and then, on this basis, Bayesian game theory is used in order to make more scientific and reasonable decisions with respect to international trade.

A Workable Framework or a Fuzzy Concept? The Regional Resilience Approach to the Evolution and Adaptability of Regional Economies

  • Cho, Cheol-Joo
    • World Technopolis Review
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    • 제3권2호
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    • pp.66-77
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    • 2014
  • This paper aims at exploring a conceptual framework of analyzing the evolutionary processes of regional economies by reconciling the notion of regional resilience and the concepts prevailing in the disciplines of evolutionary economics and geography. The resilience framework appears to offer a promising outlet with which combination of the seemingly contradictory conceptions is made possible. It can address why some regions manage to adapt to external shocks, renew themselves, or lock out themselves, while others are more locked in decline. In addition, it can also explain how the spatial organization of economic production, distribution, and consumption is transformed over time. Then, regional economic resilience, together with its accompanying vehicle of panarchy, emerges as a workable framework of explaining regional differentiation in regional economic performance and trajectories. Despite the risk of being a fuzzy concept, the resilience conception can be properly operationalized to provide policy principles of regional economic innovation adjusted to region-specific contexts.

퍼지-ARTMAP에 의한 채널 등화 (Channel Equalization using Fuzzy-ARTMAP)

  • 이정식;한수환
    • 한국멀티미디어학회논문지
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    • 제4권4호
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    • pp.333-338
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    • 2001
  • 본 논문에서는 이전에 개발된 신경회로망 채널 등화기에서 볼 수 있었던 구조의 복잡성 및 많은 학습시간의 소요 등과 같은 단점을 극복하고자 퍼지-ARTMAP 신경망을 이용하여 채널 등화기를 구성하였다. 제안된 퍼지-ARTMAP 채널 등화기는 다른 형태의 신경망을 이용한 등화기에서는 찾아 볼 수 없는 빠르고 쉬운 학습 능력을 갖고 있다. 즉, 등화기 구성에 필요한 파라미터의 수가 적으며 지역적 최소값에 빠질 우려 없이 각 계층간의 초기 연결강도를 지정할 수 있을 뿐만 아니라 기존의 학습된 데이터를 재학습시킬 필요 없이 새로운 데이터를 단순히 추가 학습시킬 수 있는 장점 등을 가지고 있다. 본 연구의 시뮬레이션 과정에서는 선형채널에서 발생된 가우시안 잡음을 동반한 이진 신호를 대상으로 퍼지-ARTMAP 채널 등화기의 성능을 LMS 기반의 선형 등화기 및 MLP와 RBF 신경망 등화기와 비교하였으며 퍼지-ARTMAP 등화기가 상대적으로 간단한 구조와 빠른 처리속도를 가짐은 물론 선형등화기로 해결하지 못했던 비선형 문제들도 해결할 수 있음을 보였다.

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