• Title/Summary/Keyword: Complex Uncertain Process

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A Strategy Evaluation Procedure using VDMP (VDMP를 이용한 전략대안 분석 및 평가절차)

  • 조용욱;박명규
    • Journal of the Korea Safety Management & Science
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    • v.3 no.2
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    • pp.133-144
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    • 2001
  • This article deals with the multiple alternative proposal of Strategy. when Decision makers meet a very complex and important problems to take a good choice. It might not be easy that we make a decision and accept the decision as an exact result of analysis at a complication and uncertain situation. Although the decision under unpredictable state is many existence and each field is classified to support it. he can not provide exact estimations and be able to specify a result and forecasting. This is the reason why the original research use Statistical Survey method and Visual Decision Making Process(VDMP) to improve decision analysis method. Therefore, Our research suggests that the VDMP utilized in the strategic decision making situation as a group decision adding tool, can be applied in the development of a process vision and implementation plan. as a result, researcher describe step by step the process of VDMP.

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Variable Structure Adaptive Control of Assembling Robot (조립용 로봇의 가변구조 적응제어)

  • 한성현
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 1997.04a
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    • pp.131-136
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    • 1997
  • This paper represent the variable structure adaptive mode control technique which is new approach to implement the robust control of industrial robot manipulator with external disturbances and parameter uncertainties. Sliding mode control is a well-known technique for robust control of uncertain nonlinear systems. The robustness of sliding model controllers can be shown in contiuous time, but digital implementation may not preserve robustness properties because the sampling process limits the existence of a true sliding mode. the sampling process often forces the trajectory to oscillate in the neighborhood of the sliding surface. Adaptive control technique is particularly well-suited to robot manipulators where dynamic model is highly complex and may contain unknown parameters. Adaptive control algorithm is designed by using the principle of the model reference adaptive control method based upon the hyperstability theory. The proposed control scheme has a simple sturcture is computationally fast and does not require knowledge of the complex dynamic model or the parameter values of the manipulator or the payload. Simulation results show that the proposed method not only improves the performance of the system but also reduces the chattering problem of sliding mode control, Consequently, it is expected that the new adaptive sliding mode control algorithm will be suited for various practical applications of industrial robot control system.

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MANAGEMENT THINKING BEHIND PERFORMANCE MEASURES

  • Yong-Woo Kim ;Glenn Ballard
    • International conference on construction engineering and project management
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    • 2005.10a
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    • pp.377-382
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    • 2005
  • The tools, methods and measures used for project control reflect underlying theories of management. Management theory has been neglected in the construction industry, which has rather focused on tools and neglected theory. This paper contributes to the theory of project management by introducing and developing two fundamental and competing conceptualizations of management: MBM (Managing-by-Means) and MBR (Managing-by-results). Current project control and performance measurement practice is based on MBR. However, project control based on MBR may not be appropriate for managing dynamic projects. The paper present the Last PlannerTM System (LPS) and Process Variance Control (PVC) as examples of methods reflecting the MBM view. It is argued first that the MBM view is appropriate for managing uncertain, complex and quick projects. The paper also explores how MBR tools and techniques may be appropriately used within an MBM framework.

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Design of Fuzzy Model-based Multi-objective Controller and Its Application to MAGLEV ATO system (퍼지 모델 기반 다목적 제어기의 설계와 자기부상열차 자동운전시스템에의 적용)

  • 강동오;양세현;변증남
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 1998.10a
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    • pp.211-217
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    • 1998
  • Many practical control problems for the complex, uncertain or large-scale plants, need to simultaneously achieve a number of objectives, which may conflict or compete with each other. If the conventional optimization methods are applied to solve these control problems, the solution process may be time-consuming and the resulting solution would ofter lose its original meaning of optimality. Nevertheless, the human operators usually performs satisfactory results based on their qualitative and heuristic knowledge. In this paper, we investigate the control strategies of the human operators, and propose a fuzzy model-based multi-objective satisfactory controller. We also apply it to the automatic train operation(ATO) system for the magnetically levitated vehicles(MAGLEV). One of the human operator's strategies is to predict the control result in order to find the meaningful solution. In this paper, Takagi-Sugeno fuzzy model is used to simulated the prediction procedure. Another str tegy is to evaluate the multiple objectives with respect to their own standards. To realize this strategy, we propose the concept of a satisfactory solution and a satisfactory control scheme. The MAGLEV train is a typical example of the uncertain, complex and large-scale plants. Moreover, the ATO system has to satisfy multiple objectives, such as seed pattern tracking, stop gap accuracy, safety and riding comfort. In this paper, the speed pattern tracking controller and the automatic stop controller of the ATO system is designed based on the proposed control scheme. The effectiveness of the ATO system based on the proposed scheme is shown by the experiments with a rotary test bed and a real MAGLEV train.

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Stochastic modelling and lifecycle performance assessment of bond strength of corroded reinforcement in concrete

  • Chen, Hua-Peng;Nepal, Jaya
    • Structural Engineering and Mechanics
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    • v.54 no.2
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    • pp.319-336
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    • 2015
  • Life cycle performance of corrosion affected RC structures is an important and challenging issue for effective infrastructure management. The accurate condition assessment of corroded RC structures mainly depends on the effective evaluation of deterioration occurring in the structures. Structural performance deterioration caused by reinforcement corrosion is a complex phenomenon which is generally uncertain and non-decreasing. Therefore, a stochastic modelling such as the gamma process can be an effective tool to consider the temporal uncertainty associated with performance deterioration. This paper presents a time-dependent reliability analysis of corrosion affected RC structures associated bond strength degradation. Initially, an analytical model to evaluate cracking in the concrete cover and the associated loss of bond between the corroded steel and the surrounding cracked concrete is developed. The analytical results of cover surface cracking and bond strength deterioration are examined by experimental data available. Then the verified analytical results are used for the stochastic deterioration modelling, presented here as gamma process. The application of the proposed approach is illustrated with a numerical example. The results from the illustrative example show that the proposed approach is capable of assessing performance of the bond strength of concrete structures affected by reinforcement corrosion during their lifecycle.

The Explicit Treatment of Model Uncertainties in the Presence of Aleatory and Epistemic Parameter Uncertainties in Risk and Reliability Analysis

  • Ahn, Kwang-ll;Yang, Joon-Eon
    • Nuclear Engineering and Technology
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    • v.35 no.1
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    • pp.64-79
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    • 2003
  • In the risk and reliability analysis of complex technological systems, the primary concern of formal uncertainty analysis is to understand why uncertainties arise, and to evaluate how they impact the results of the analysis. In recent times, many of the uncertainty analyses have focused on parameters of the risk and reliability analysis models, whose values are uncertain in an aleatory or an epistemic way. As the field of parametric uncertainty analysis matures, however, more attention is being paid to the explicit treatment of uncertainties that are addressed in the predictive model itself as well as the accuracy of the predictive model. The essential steps for evaluating impacts of these model uncertainties in the presence of parameter uncertainties are to determine rigorously various sources of uncertainties to be addressed in an underlying model itself and in turn model parameters, based on our state-of-knowledge and relevant evidence. Answering clearly the question of how to characterize and treat explicitly the forgoing different sources of uncertainty is particularly important for practical aspects such as risk and reliability optimization of systems as well as more transparent risk information and decision-making under various uncertainties. The main purpose of this paper is to provide practical guidance for quantitatively treating various model uncertainties that would often be encountered in the risk and reliability modeling process of complex technological systems.

MVL-Automata for General Purpose Intelligent Model (범용 지능 모델을 위한 다치 오토마타)

  • 김두완;이경숙;최경옥;정환묵
    • Journal of the Korean Institute of Intelligent Systems
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    • v.11 no.4
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    • pp.311-314
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    • 2001
  • Recently, research on Intelligent Information Process has actively been under way JD various areas and gradually extended to be adaptive to uncertain and complex dynamic environments. This paper presents a Multiple Valued Logic Automata(MVL-Automata) Model, utilizing properties of difference in a Multiple Valued Logic function. That is, MVL-Automata is able to be autonomously adapted to dynamic changing since an input stling is mapped to the value of a Multiple Valued Logic function and the property of difference in a Multiple Valued Logic function is applied to state transition. Therefore, Multiple Valued Logic Automata can be widely applied to the modeling dynamically of changing environments.

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A Study on the Control of Nonlinear Dynamical System Using the Fuzzy Model Based Controller (퍼지 모델 기반 제어기를 이용한 비선형 동적 시스템의 제어에 관한 연구)

  • Chang, Wook;Kwon, Oh-Kook;Joo, Young-Hoon;Park, Jin-Bae
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 1997.10a
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    • pp.181-184
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    • 1997
  • This paper propose the systematic procedure of the fuzzy model based controller for the continuous nonlinear system. Fuzzy controller have been successfully applied to many uncertain and complex industrial plants. The design of the fuzzy controller mainly depends on the knowledge from the expert who are familiar with the plant by trial and error. Therefore we need more systematic approach to the design of the fuzzy controller. In this paper, we design fuzzy model based controller applied to the nonlinear system. Unlike the design procedures reported in[8] and[9], we use the nonlinear process directly in designing the controller. This controller has been successfully applied to an inverted pendulum.

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My Humble Thoughts on Political Communication Research in Asia

  • Inoguchi, Takashi
    • Asian Journal for Public Opinion Research
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    • v.2 no.4
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    • pp.228-247
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    • 2015
  • Politics is defined as who gets what, when, and how. Communication is defined as the process, outcomes and effects of message transmission through a medium. Thus political communication in Asia, the most dynamic and uncertain region of the world, has been very dense, requiring rigorous scientific analysis and culturally sensitive reflection. Mass media brought about a revolution in political communication in the last century. In the 21st century, complex monitory devices from the state and international organizations and from the society and transnational groups have transformed the features of political communication. It has triggered another revolution in political communication. Illustrations are given focusing on Asia. A theoretical reflection from the angle of political science is attempted focusing on political communication medium and its effects. I compare no medium (face-to-face communication), mass media, and social media in relation to their effects.

Creation of System Dynamics in an Uncertain and Complex Market: The Case of Korea's Evolving Biopharmaceutical Industry

  • Lee, Jeong Hyop;Kim, Jaewon;Hyeon, Byung-Hwan
    • Asian Journal of Innovation and Policy
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    • v.8 no.2
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    • pp.180-207
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    • 2019
  • This article explores the historical evolutionary process of the biopharmaceutical industry of Korea, and how intentional and unintentional policy interventions have triggered the creation of the industry's system dynamics and paved the way for the generation of a few global leading products, including biosimilar, as well as next-generation therapeutics of gene and cell. The policies cover the simple technology transfer of API synthesis to overcome the endemic parasitic disease, new substance patent adoption and new drug development consortia, human resource development, various national initiatives influenced by the Human Genome Project, and venture promotion schemes. The scope and implementation tools under these policies have been aligned and refined to transform traditional fine chemical-based pharmaceuticals, to stimulate large companies' participation and to create technology-based venture companies in the biopharma business of Korea.