• Title/Summary/Keyword: dynamic uncertainties

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The Effect on Performance with SCM Dynamic Capabilities in the Pharmaceutical Industry : Mediated Through Cooperational Relationship (제약산업의 SCM 동적역량이 성과에 미치는 영향: 협력관계를 매개로 하여)

  • Seo, Young-Kyu;Song, Dohan;Huh, Hoon
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.44 no.3
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    • pp.192-206
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    • 2021
  • The pharmaceutical industry is an industry that provides medicines related to the health and life of the people. The pharmaceutical industry is a traditional regulation industry with the characteristics of R&D(Research and Development), purchasing, manufacturing, distribution and consumption under strict government management. Until now, pharmaceutical companies have continued to make efforts to maintain competitiveness through patent management, new product development, and marketing. However, industries are rapidly changing, including rising costs for developing new products and expanding generic markets. As these changes and uncertainties in the management environment increase, efforts are required to improve the competitiveness of the pharmaceutical industry from a new perspective. In this study, we intend to examine the impact of SCM(Supply Chain Management) dynamic capability of pharmaceutical companies on corporate performance through partnerships to respond to market changes and uncertainties. It was determined that the agility, visibility and flexibility that constitutes the SCM dynamic capabilities would affect the performance of pharmaceutical companies. In this study, the importance of SCM dynamic capabilities and cooperative relationships was identified through surveys by SCM managers of pharmaceutical companies. Consequently, in the pharmaceutical industry, which is a regulatory industry, we have identified that SCM dynamic capabilities and cooperative relationships with partner companies have a significant impact on corporate performance.

A Study on State Space H2H Controller Using Sliding Mode (슬라이딩 모드를 이용한 상태공간 H2H 제어기에 관한 연구)

  • 김민찬;박승규;안호균
    • Journal of Institute of Control, Robotics and Systems
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    • v.9 no.11
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    • pp.868-873
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    • 2003
  • $H_{\infty}$ control has been applied to the design of practical control systems widely because of its robustness. It can minimize $H_{\infty}$ norm of the transfer function between the desired output and the disturbances. The SMC(Sliding Mode Control) is more robust and give the better performance than the $H_{\infty}$ control if the matching condition is satisfied. A controller which can have the advantages of $H_{\infty}$ control and the SMC is proposed to add the robustness of the SMC to the $H_{\infty}$ controller. Its design is based on the augmented system of which dynamics have one higher order than that of the original system and has the same dynamic as the desired system in spite of uncertainties. The dynamic of proposed sliding surface is the same dynamic as the system controlled by $H_{\infty}$ controller without the uncertainties which satisfy the matching condition.

Uncertainty Evaluation of Dynamic Pressure Calibrator by Monte Carlo Simulation (몬테카를로 모사를 이용한 동압력 교정기 불확도 평가)

  • Kim, Moon-Ki
    • Journal of the Korea Institute of Military Science and Technology
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    • v.13 no.4
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    • pp.665-672
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    • 2010
  • This paper describes Monte Carlo Simulation(MCS) to assess the uncertainty of dynamic pressure calibrator and the expanded uncertainty results that were compared by GUM approximation and MCS. MCS uncertainties were computed using defining a domain of possible inputs, generating inputs randomly using probability distribution, performing a deterministic computation repeatedly and aggregating the results. It was revealed that the expanded uncertainty between GUM and MCS was different from each other. the expanded uncertainties were 0.5366%, 0.4856%, respectively. MCS is a suitable method for determining the uncertainty of simple and complex measurement systems. It should be more widely used and studied in measurement uncertainty calculations.

Robust Missile Autopilot Design using Dynamic Inversion and PI Control (Dynamic Inversion과 PI 제어를 이용한 견실한 유도탄 오토파일롯 설계)

  • Cho, Sung-Jin
    • Journal of the Korea Institute of Military Science and Technology
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    • v.10 no.2
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    • pp.53-60
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    • 2007
  • This paper presents a robust nonlinear autopilot design method based on dynamic inversion and PI(Proportional-Integral) control law. The new controller structure which is different from previous work is composed of classical linear PI control law and nonlinear fast dynamic inversion. A pitch axis model of highly maneuverable missiles and a linearized model for designing Pl controller are presented. The performance of proposed method is illustrated via nonlinear simulations including aerodynamic uncertainties and actuator dynamics.

Nonlinear soil parameter effects on dynamic embedment of offshore pipeline on soft clay

  • Yu, Su Young;Choi, Han Suk;Lee, Seung Keon;Park, Kyu-Sik;Kim, Do Kyun
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.7 no.2
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    • pp.227-243
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    • 2015
  • In this paper, the effects of nonlinear soft clay on dynamic embedment of offshore pipeline were investigated. Seabed embedment by pipe-soil interactions has impacts on the structural boundary conditions for various subsea structures such as pipeline, riser, pile, and many other systems. A number of studies have been performed to estimate real soil behavior, but their estimation of seabed embedment has not been fully identified and there are still many uncertainties. In this regards, comparison of embedment between field survey and existing empirical models has been performed to identify uncertainties and investigate the effect of nonlinear soil parameter on dynamic embedment. From the comparison, it is found that the dynamic embedment with installation effects based on nonlinear soil model have an influence on seabed embedment. Therefore, the pipe embedment under dynamic condition by nonlinear parameters of soil models was investigated by Dynamic Embedment Factor (DEF) concept, which is defined as the ratio of the dynamic and static embedment of pipeline, in order to overcome the gap between field embedment and currently used empirical and numerical formula. Although DEF through various researches is suggested, its range is too wide and it does not consider dynamic laying effect. It is difficult to find critical parameters that are affecting to the embedment result. Therefore, the study on dynamic embedment factor by soft clay parameters of nonlinear soil model was conducted and the sensitivity analyses about parameters of nonlinear soil model were performed as well. The tendency on dynamic embedment factor was found by conducting numerical analyses using OrcaFlex software. It is found that DEF was influenced by shear strength gradient than other factors. The obtained results will be useful to understand the pipe embedment on soft clay seabed for applying offshore pipeline designs such as on-bottom stability and free span analyses.

An Interval Approach for Design and Analysis of Mechanical Systems with Uncertainties

  • Shin, Jae-Kyun;Li Chen;Jang, Woon-Geun
    • International Journal of Precision Engineering and Manufacturing
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    • v.3 no.4
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    • pp.5-14
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    • 2002
  • This paper addresses the challenges of dealing with uncertainties based on interval analysis. An interval approach is proposed on the basis of Boundary Selection Method (BSM) for treating systems of linear interval equations in the presence of columnwise dependencies. An iterative procedure is developed for the problem solving where uncertainties are characterized in the form of interval quantities. An applied example is used to illustrate effectiveness and usefulness of the proposed approach. This new method can be applied for such circumstances that involve finite element analysis of structures, inverse dynamic analysis of mechanisms, and worst case design studies in the presence of the uncertainties.

Consensus of High-order Linear Systems With Parameter Uncertainties (파라미터 불확실성을 갖는 고차 선형시스템들의 상태일치)

  • Kim, Su-Bum;Choi, Hyoun-Chul;Kim, Hyoung-Joon;Shim, Hyung-Bo;Seo, Jin-Heon
    • Proceedings of the IEEK Conference
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    • 2009.05a
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    • pp.67-69
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    • 2009
  • This paper deals with the consensus problem for multi-agent linear dynamic systems with parameter uncertainties. All the agents are identical high-order linear systems with parameter uncertainties and their state information is exchanged through a communication network. It is shown that a consensus is achieved if there exists a feasible solution to a set of linear matrix inequalities obtained for a simultaneous stabilization problem for multiple systems. A numerical example is presented to show the effectiveness of the proposed method.

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A method for the determination of transient flow rates from pressure measurements (압력측정을 이용한 과도기유량의 결정방법에 관한 연구)

  • 이성래
    • 제어로봇시스템학회:학술대회논문집
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    • 1992.10a
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    • pp.724-729
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    • 1992
  • A transient hydraulic flow rate computation scheme is described here so that the transient hydraulic flow rate can be determined using the dynamic pressure measurements at the ends of a straight flowline with a dynamic, model of the hydraulic line. Simulation results indicate that the method is relatively robust to realistic levels of uncertainties in the fluid properties.

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Adaptive-learning control of vehicle dynamics using nonlinear backstepping technique (비선형 백스테핑 방식에 의한 차량 동력학의 적응-학습제어)

  • 이현배;국태용
    • 제어로봇시스템학회:학술대회논문집
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    • 1997.10a
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    • pp.636-639
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    • 1997
  • In this paper, a dynamic control scheme is proposed which not only compensates for the lateral dynamics and longitudinal dynamics but also deal with the yaw motion dynamics. Using the dynamic control technique, adaptive and learning algorithm together, the proposed controller is not only robust to disturbance and parameter uncertainties but also can learn the inverse dynamics model in steady state. Based on the proposed dynamic control scheme, a dynamic vehicle simulator is contructed to design and test various control techniques for 4-wheel steering vehicles.

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Study on the Effects of the Interactions between Demand and Supply Uncertainties on Supply Chain Costs (수요 불확실성과 공급 불확실성의 상호 작용이 공급 사슬 비용에 미치는 효과에 대한 연구)

  • Park Sangwook;Kim Soo-Wook
    • Journal of the Korean Operations Research and Management Science Society
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    • v.30 no.3
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    • pp.81-93
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    • 2005
  • This paper models supply chain uncertainties in the dynamic Newsboy Problem context. The system consists of one supplier and one retailer who place an order to the supplier every period. Demand uncertainty is modeled as stochastic period demand, and supply uncertainty as the uncertainty in quantities delivered by the supplier. The supplier delivers exactly the amount ordered by the retailer with probability of $\beta$ and the amount minus K with probability of $(1-\beta)$ We formulate the problem as a dynamic programming problem and derive the first-order optimality condition. Through a numerical study, we measure the extent to which the cost decrease due to the reduction in supply uncertainty depends on the level of demand uncertainty. One of the most important findings In this paper is that this cost decrease is relatively small if demand uncertainty is kept high, and vice versa. We also backup this numerical result by analyzing the distribution of ending Inventory under the supply and demand uncertainties.