• 제목/요약/키워드: Process disturbances

검색결과 245건 처리시간 0.025초

Clinical Effectiveness of Korea Ginseng on Climacteric Disturbances and Its Possible Mechanism of Action

  • Ogita, Sacchio
    • 고려인삼학회:학술대회논문집
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    • 고려인삼학회 1990년도 Proceedings of International Symposium on Korean Ginseng, 1990, Seoul, Korea
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    • pp.20-24
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    • 1990
  • The climacteric is that phase in the aging process during which a woman passes from the reproductive to the non-reproductive stage. The signals, such as hot flashes, vaso-motoric disturbances, perspiration, stiff shoulders, emotional symptoms, are refereed to as climacteric disturbances. Treatment of climacteric symptoms centers on estrogen replacement and transquilizers, but there are many problems to be solved to use these hormones/drugs as far as dosage, duration and complications are concerned. The care of women during the climacteric years should provide relief of distressing symptoms with as high a degree of safety as possible. From this viewpoint, we used red ginseng powder to those patients with high menopausal index successfully. We studied its mechanism of action and proved that red ginseng improved the micro-circulation system via improvement of erythrocyte deferability which enhanced sex steroidgenesis consequently

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DESIGN OF AN $H^{\infty}$ CONTROLLER WITH PREVIEW

  • Choi, Chintae;Kim, Jong-Shik
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1996년도 Proceedings of the Korea Automatic Control Conference, 11th (KACC); Pohang, Korea; 24-26 Oct. 1996
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    • pp.44-47
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    • 1996
  • An optimal preview controller based on the discrete-time $H_{.inf}$ control is presented. The preview controller is synthesized by considering the bounded unknwon disturbances as well as previewable commands and disturbances. The controller derivation procedure is analogous to the LQ-based scheme. The designed preview gain matrix has a similar structure as the LQ-based one. As the infinity norm .gamma. of the transfer function matrix tends to .inf., the preview gains obtained by $H_{\infty}$ control method approach to the gains by the LQR. The LQ-based preview gains are verified to be subsets of the $H_{.inf}$ -based preview gains..

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주기적 외란을 수반하는 시스템의 적응 신경망 회로 기법에 의한 오차 제거 (Error elimination for systems with periodic disturbances using adaptive neural-network technique)

  • 김한중;박종구
    • 제어로봇시스템학회논문지
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    • 제5권8호
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    • pp.898-906
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    • 1999
  • A control structure is introduced for the purpose of rejecting periodic (or repetitive) disturbances on a tracking system. The objective of the proposed structure is to drive the output of the system to the reference input that will result in perfect following without any changing the inner configuration of the system. The structure includes an adaptation block which learns the dynamics of the periodic disturbance and forces the interferences, caused by disturbances, on the output of the system to be reduced. Since the control structure acquires the dynamics of the disturbance by on-line adaptation, it is possible to generate control signals that reject any slowly varying time-periodic disturbance provided that its amplitude is bounded. The artificial neural network is adopted as the adaptation block. The adaptation is done at an on-line process. For this , the real-time recurrent learning (RTRL) algoritnm is applied to the training of the artificial neural network.

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Fault Diagnosis and Accommodation of Linear Stochastic Systems with Unknown Disturbances

  • Lee, Jong-Hyo;Joon Lyou
    • Transactions on Control, Automation and Systems Engineering
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    • 제4권4호
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    • pp.270-276
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    • 2002
  • An integrated robust fault diagnosis and fault accommodation strategy for a class of linear stochastic systems subjected to unknown disturbances is presented under the assumption that only a single fault may occur at a given time. The strategy is based on the fault isolation and estimation using a bank of robust two-stage Kalman filters and introduction of the additive compensation input for cancelling out the fault's effect on the system. Each filter is set up such that the residual is decoupled from unknown disturbances and fault with the influence vector designed in the filter. Simulation results for the simplified longitudinal flight control system with parameter uncertainties, process and sensor noises demonstrate the effectiveness of the present approach.

Recognition and Classification of Power Quality Disturbances on the basis of Pattern Linguistic Values

  • Liu, XiaoSheng;Liu, Bo;Xu, DianGuo
    • Journal of Electrical Engineering and Technology
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    • 제11권2호
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    • pp.309-319
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    • 2016
  • This paper presents a new recognition and classification method for power quality (PQ) disturbances on the basis of pattern linguistic values. This method solves the difficulty of recognizing disturbances rapidly and accurately by using fuzzy logic. This method uses classification disturbance patterns to define the linguistic values of fuzzy input variables and used the input variables of corresponding disturbance pattern to set membership functions. This method also sets the fuzzy rules by analyzing the distribution regularities of the input variable values. One characteristic of this method is that the linguistic values of fuzzy input variables and the setting of membership functions are not only related to the input variables but also to the character of classification disturbance and the classification results. Furthermore, the number of fuzzy rules is equal to the number of disturbance patterns. By using this method for disturbance classification, the membership function and design of fuzzy rules are directly related to the objective of classification, thus effectively reducing the complexity of the design process and yielding accurate classification results. The classification results of the simulation and measured data verify the feasibility and effectiveness of this method.

Frequency response of film casting process

  • Hyun, Jae-Chun;Lee, Joo-Sung;Jung, Hyun-Wook
    • Korea-Australia Rheology Journal
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    • 제15권2호
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    • pp.91-96
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    • 2003
  • The sensitivity of the product to the ongoing sinusoidal disturbances of the process has been investigated in the film casting of viscoelastic polymer fluids using frequency response analysis. As demonstrated for fiber spinning process (Jung et al., 2002; Devereux and Denn, 1994), this frequency response analysis is useful for examining the process sensitivity and the stability of extensional deformation processes including film casting. The results of the present study reveal that the amplification ratios or gains of the process/product variables such as the cross-sectional area at the take-up to disturbances exhibit resonant peaks along the frequency regime as expected for the systems having hyperbolic characteristics with spilt boundary conditions (Friedly, 1972). The effects on the sensitivity results of two important parameters of film casting, i.e., the fluid viscoelasticity and the aspect ratio of the casting equipment have been scrutinized. It turns out that depending on the extension thinning or thickening nature of the fluid, increasing viscoelasticity results in enlargement or reduction of the sensitivity, respectively. As regards the aspect ratio, it has been found that an optimum value exists making the system least sensitive. The present study also confirms that the frequency response method produces results that corroborate well those by other methods like linear stability Analysis and transient solutions response. (Iyengar and Co, 1996; Silagy et al., 1996; Lee and Hyun, 2001).

인공지능을 이용한 공정제어 (Application of artificial intelligence to industrial process control)

  • 유병휘
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1986년도 한국자동제어학술회의논문집; 한국과학기술대학, 충남; 17-18 Oct. 1986
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    • pp.248-250
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    • 1986
  • This paper explain application of expert system techniques from the latest theories of artificial intelligence to industrial process control. This controller continuously monitors a loop's response to disturbances and adapts the tuning parameters (P.I.D) to provide the best response to load upset or set-point change.

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A Note on Relay Feedback Identification Under Static Load Disturbances

  • Kaya, Ibrahim
    • Journal of Electrical Engineering and Technology
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    • 제10권1호
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    • pp.395-400
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    • 2015
  • Obtaining the parameters for PID controllers based on limit cycle information for the process in a relay controlled feedback loop has become an accepted practical procedure. If the form of the plant transfer function is known, exact expressions for the limit cycle frequency and amplitude can be derived so that their measurements, assumed error free, can be used to calculate the true parameter value. In the literature, parameter estimation for an assumed form of the plant transfer function has generally been considered for disturbance free cases, except a recently published work of the author. In this paper additional simulation results are reported on exact parameter estimation from relay autotuning under static load disturbances.

제조 공정상 랜덤 특성을 고려한 IC 최악조건 해석 (IC Worst Case Analysis Considered Random Fluctuations on Fabrication Process)

  • 박상봉;박노경;전흥우;문대철;차균현
    • 대한전자공학회논문지
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    • 제25권6호
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    • pp.637-646
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    • 1988
  • The CMOS physical parameters are extracted using by processing models in fabrication steps, processing parameters, fabrication disturbances, control parameters. Statistical CMOS process and device simulator is proposed to evaluate the effect of inherent fluctuations in IC fabrication. Using this simulator, we perform worst case analysis in terms of statistically independent disturbances and compare this proposed method to Monte Carlo method, previous Worst Case method. And simulation results with this proposed method are more accurate than the past worst case analysis. This package is written in C language and runs on a IBM PC AT(OPUS).

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불규칙 궤도외란을 받는 자기부상열차의 진동해석 및 2차현가장치 동적설계 (Vertical Vibration Analysis of a Magnetically Levitated Vehicle due to Random Track Disturbances and Dynamic Design of Its Secondary Suspensions)

  • 최영휴;허신;김유일
    • 연구논문집
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    • 통권22호
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    • pp.39-46
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    • 1992
  • A dynamic design process was proposed for the design of the secondary suspension characteristics of a magnetically levitated vehicle(MAGLEV). It is based on a ride quality-secondary stroke trade-off. For the vertical vibration analysis, a magnetically levitated vehicle was simplified as 2 d.o.f. linear model, and FRA's class-6-track irregularities were considered as exciting disturbances. The optimum value of airspring stiffness and damping coefficient for the secondary suspension of a prototype MAGLEV was determined using this proposed design process.

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