With the increasing use of powerful wind farms, there is not only an increase in the share of decentralized network input, but also in the related share of power fluctuations. To be able to examine the effects of such...
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With the increasing use of powerful wind farms, there is not only an increase in the share of decentralized network input, but also in the related share of power fluctuations. To be able to examine the effects of such power fluctuations on the control behavior of the power system, extensive experimental testing was carried out at a wind power plant on a low mountain range in Germany and at a wind farm on the German coast. Eased on these studies, dynamic models for the decentralized simulation of the wind speed, of the dynamic behavior of individual wind power plants and of entire wind farms were developed and parameterized. The model quality achieved is verified in each case by a comparison of simulated wind-speed and power curves with the correspondingly measured time behavior.
Thermal stresses of thick-walled components in power plants are the limiting factors for rapid start-up, shut-down or load changes. In current industrial practice, thermal stresses are calculated from differential tem...
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Thermal stresses of thick-walled components in power plants are the limiting factors for rapid start-up, shut-down or load changes. In current industrial practice, thermal stresses are calculated from differential temperature measurements. In this paper a method is described to calculate thermal stresses from readily available plant measurements. Mathematical models of the critical thickwalled components were used for unit 8 at the GKM power plant in Germany in order to reduce the instrumentation costs and improve the quality of the thermal stress calulation. Operational experience has shown that the estimated inner and mean temperatures are considerably more accurate than the previously used measured values.
Telemanipulation is studied by many disciplines;however, this is generally done independently. This paper is intended to contribute to the integration of these disciplines by bridging the gap between the control engin...
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Telemanipulation is studied by many disciplines;however, this is generally done independently. This paper is intended to contribute to the integration of these disciplines by bridging the gap between the control engineers in the man-machine systems field, the computer scientists in the field of human-computer interaction, and the biomedical researchers in the field of severely bodily disabled persons, Three major problems in telemanipulation are recognised, i.e. the lack of tactile and touch information, the lack of information for depth perception since visual displays only generate 2D data, and the existing time-delay in the human operator - telemanipulator - control loop. For control theory the importance of the Internal Model for obtaining optimal filtering and control is highlighted, and for perception theory the choice for the so-called ''ecological approach'' is explained. control theory and perception theory both point to the importance of an increase in feedback modalities, for instance by pointing to the importance of proprioceptive feedback for 3D perception, and by designing two-handed controls that pay attention to the asymmetry in the effectivities of both hands. It is argued that a combination of proprioceptive feedback and 3D perception is needed for good telemanipulation, and for telepresence. Also, a short note on compensation methods using predictive displays is given. Finally, the traditional approach will be compared with the ecological approach. Copyright (C) 1997 Elsevier Science Ltd.
The presented paper is devoted to the study of some problems concerning the pulsatile flow of blood in tubes with circular and elliptic cross-section. The adopted two-phase viscous model is based on the Saffman equati...
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The presented paper is devoted to the study of some problems concerning the pulsatile flow of blood in tubes with circular and elliptic cross-section. The adopted two-phase viscous model is based on the Saffman equations (1962) with appropriate symplifying assumptions. The resulting system is mathematically simple but also acceptable in physical situations. The analytical and simulated results for different vascular diameter are in good agreement with the biological parameters under the given experimental conditions.
Parameters characterizing the intimate functioning of biomedicalsystems are usually not measurable. Dynamic state models usually nonlinear are formulated and input-output experiments designed to solve this problem as...
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Parameters characterizing the intimate functioning of biomedicalsystems are usually not measurable. Dynamic state models usually nonlinear are formulated and input-output experiments designed to solve this problem as a parameter estimation problem. A fundamental problem for well posedness of parameter estimation is a priori global identifiability which deals With uniqueness of the solution for the unknown model parameters. In this paper, we study global identifiability of nonlinear dynamic models of biomedicalsystems. A neew algorithm based on differential algebra is presented Which calculates the exhaustive summary by means the characteristic set associated to the system and allows the study of global identifiability for general model structures and multi input-multi output configurations. Three case studies are presented, a model of drug kinetics in the body, a model of glucose metabolism in the brain and a model of insulin control on body tissue glucose utilization
It is generally believed that evolution is a mechanism that creates organisms, each time more complex and performant. This paper studies the existence of four cavities in the heart of the mamals. It is shown by simula...
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It is generally believed that evolution is a mechanism that creates organisms, each time more complex and performant. This paper studies the existence of four cavities in the heart of the mamals. It is shown by simulation that atrial contraction preceeding slighty ventricular contraction improves the ejection of the heart. The atrial contraction simulated through a cardiac pump model in the late phase of diastole, evidences that ventricular pump function is influencing ventricular filling. The systemic circulation is represented by windkessel model. The experiments were performed on microcomputer IBM-pc compatible by using the bond graphs tools, on simulation program Tutsim.
Thermal stresses of thick-walled components in power plants are the limiting factors for rapid start-up, shut-down or load changes. In current industrial practice, thermal stresses are calculated from differential tem...
详细信息
ISBN:
(纸本)0080423620
Thermal stresses of thick-walled components in power plants are the limiting factors for rapid start-up, shut-down or load changes. In current industrial practice, thermal stresses are calculated from differential temperature measurements. In this paper a method is described to calculate thermal stresses from readily available plant measurements. Mathematical models of the critical thickwalled components were used for unit 8 at the GKM power plant in Germany in order to reduce the instrumentation costs and improve the quality of the thermal stress calculation. Operational experience has shown that the estimated inner and mean temperatures are considerably more accurate than the previously used measured values.
With the increasing use of powerful wind farms, there is not only an increase in the share of decentralized network input, but also in the related share of power fluctuations. To be able to examine the effects of such...
详细信息
ISBN:
(纸本)0080423620
With the increasing use of powerful wind farms, there is not only an increase in the share of decentralized network input, but also in the related share of power fluctuations. To be able to examine the effects of such power fluctuations on the power system control behavior, extensive experimental testing was carried out at a wind power plant in a German low mountain range and at a wind farm on the German coast. Based on these studies, dynamic models for the decentralized simulation of the wind speed, of the dynamic behavior of individual wind power plants and of entire wind farms were developed and parameterized. The achieved model quality is verified in each case by the comparison of simulated wind-speed and power curves with the correspondingly measured time behavior.
In this paper, we present our recent results which may play a role in improving the situation in the practical implications of mathematical modeling of cancer chemotherapy. We are concerned with control problems for a...
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In this paper, we present our recent results which may play a role in improving the situation in the practical implications of mathematical modeling of cancer chemotherapy. We are concerned with control problems for a model of the dynamics of emergence of resistance of cancer cells to chemotherapy, as understood based on recent progress in molecular biology. In some special cases of this model, their asymptotic behavior and the stability problem for the infinite dimensional case were studied. In the case of finite initial condition the stability conditions were derived by asymptotical analysis of the analytical solution to the system of equations. In the case of initial condition with infinite number of elements the stability verification was based on the spectral properties of the infinitesimal generator of the system.
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