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Lumped and distributed-parameter Circuit models of the Electromagnetic Clamp

IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY 2016年第4期58卷 1007-1015页

作者： Toscani, Nicola Spadacini, Giordano Grassi, Flavia Pignari, Sergio A. Politecn Milan Dept Elect Informat & Bioengn I-20133 Milan Italy

This paper presents two circuit models of the electromagnetic ( EM) clamp defined in Standard IEC 61000-4-6 for conducted-immunity ( CI) testing. First, a lumped-parameter circuit model is extracted from measurements of scattering parameters. This model is merely behavioral since it provides a valid representation of the EM clamp at external ports up to 1 GHz, whereas physical interpretation of the involved sources/impedances is possible under 10MHz only. To extend physical insight at higher frequencies, a distributed-parameter circuit model is proposed, which is based on the description of the internal structure of the EM clamp as a three-conductor transmission line. Unknown model parameters ( such as the magnetic permeability of ferrite rings) are identified by optimized fitting of ad hoc measurements. Both models are eventually validated by experiments performed in an idealized CI test setup. Several observations on the operating principles and features of the EM clamp are inferred from the two complementary modeling approaches.

关键词： Conducted susceptibility distributed-parameter models electromagnetic (EM) clamp transmission lines

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MEASUREMENT OF REGIONAL CEREBRAL BLOOD-FLOW WITH POSITRON EMISSION TOMOGRAPHY - A COMPARISON OF [O-15]WATER TO [C-11] BUTANOL WITH distributed-parameter AND COMPARTMENTAL-models

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JOURNAL OF CEREBRAL BLOOD FLOW AND METABOLISM 1993年第5期13卷 733-747页

作者： QUARLES, RP MINTUN, MA LARSON, KB MARKHAM, J MACLEOD, AM RAICHLE, ME WASHINGTON UNIV SCH MEDEDWARD MALLINCKRODT INST RADIOLDIV RADIAT SCI510 S KINGSHIGHWAYST LOUISMO 63110 UNIV FLORIDA DEPT RADIOLGAINESVILLEFL 32611 UNIV PITTSBURGH DIV NUCL MEDPITTSBURGHPA 15260 WASHINGTON UNIV DEPT NEUROL & NEUROSURGST LOUISMO 63130 WASHINGTON UNIV INST BIOMED COMPST LOUISMO 63130

To further our understanding of the best way to measure regional CBF with positron emission tomography (PET), we directly compared two candidate tracers ([O-15]water and [C-11]butanol, administered intravenously) and two popular implementations of the one-compartment (1C) model: the autoradiographic implementation representing a single PET measurement of tissue radioactivity over 1 min and a dynamic implementation representing a sequence of measurements of tissue radioactivity over 200 s. We also examined the feasibility of implementing a more realistic, and thus more complex, distributed-parameter (DP) model by assigning fixed values for all of its parameters other than CBF and tracer volume of distribution (Vd), a requirement imposed by the low temporal resolution and statistical quality of PET data. The studies were performed in three normal adult human subjects during paired rest and visual stimulation. In each subject seven regions of interest (ROIs) were selected, one of which was the primary visual cortex. The corresponding ROI were anatomically equivalent in the three subjects. Regional CBF, V(d), tracer arrival delay, and dispersion were estimated for the dynamic data curves. A total of 252 parameter sets were estimated. With [C-11]butanol both implementations of the 1C model provided similar results (r = 0.97). Flows estimated using the 1C models were lower (p < 0.01) with [O-15]water than with [C-11]butanol. In comparison with the 1C model, the constrained version of the DP used in these studies performed inadequately, overestimating high flow and underestimating low flow with both tracers, possibly as the result of the necessity of assigning fixed values for all of its parameters other than CBF and V(d).

关键词： BLOOD FLOW TRACERS BRAIN ACTIVATION COMPARTMENTAL models DISPERSION AND DELAY distributed-parameter models POSITRON EMISSION TOMOGRAPHY REGIONAL CEREBRAL BLOOD FLOW

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Building a metamodel of an irrigation district distributed-parameter model

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AGRICULTURAL WATER MANAGEMENT 2010年第2期97卷 187-200页

作者： Galelli, S. Gandolfi, C. Soncini-Sessa, R. Agostani, D. Politecn Milan Dipartimento Elettron & Informaz I-20133 Milan Italy Univ Milan Dipartimento Ingn Agr I-20133 Milan Italy

Complex decision-making problems, related to planning and management of irrigation water resources, generally preclude the use of large, distributed-parameter models, which are then commonly substituted by lumped-parameter models. This paper, with the aim of improving the quality of these latter, introduces a new approach for their design. This approach is based on metamodelling, which proposes to identify a simple, lumped-parameter model on the basis of the data produced via simulation with a distributed-parameter model. The approach proposed is tested on a real-world case study, namely the identification of a metamodel describing the water demand of the Muzza-Bassa Lodigiana irrigation district (Italy). The metamodel, which inherits the physical description of the original distributed-parameter model, is sufficiently simple to permit the resolution of an optimal control problem, i.e. the design, via stochastic dynamic programming, of the release policy of Lake Como, serving the Muzza irrigation district. (C) 2009 Elsevier B.V. All rights reserved.

关键词： Flood irrigation water management distributed-parameter models Lumped-parameter models Metamodels Green water Blue water

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Combining metamodelling and stochastic dynamic programming for the design of reservoir release policies

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ENVIRONMENTAL MODELLING & SOFTWARE 2010年第2期25卷 209-222页

作者： Galelli, S. Soncini-Sessa, R. Politecn Milan Dipartimento Elettron & Informaz I-20133 Milan Italy

Increasing worldwide water withdrawal for irrigation purposes requires a more efficient management of water resources and an accurate description of irrigation water demand. This paper, with the aim of thinking 'in blue and green water terms', proposes a new approach for the design of release policies in reservoir systems serving irrigation districts. It is based on the solution of an optimal control problem, where the dynamics of the irrigation demand is modelled through a metamodel, i.e. a simple model identified on the basis of the data produced by a distributed-parameter, conceptual model. The metamodel inherits the physical description of the distributed-parameter model and, at same time, is sufficiently simple to allow the solution of the optimal control problem with stochastic dynamic programming. The proposed approach is tested on a real-world case study, the management of the Lake Como system, for which it provides satisfactory results. (C) 2009 Elsevier Ltd. All rights reserved.

关键词： Integrated water resources management Metamodelling distributed-parameter models Stochastic dynamic programming Water reservoirs management Irrigation canals control

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Review article: Numerical simulation of adsorption heat pumps

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ENERGY 2016年 100卷 310-320页

作者： Pesaran, Alireza Lee, Hoseong Hwang, Yunho Radermacher, Reinhard Chun, Ho-Hwan Univ Maryland Dept Mech Engn Ctr Environm Energy Engn 4164 Glenn L Martin Hall Bldg College Pk MD 20742 USA Pusan Natl Univ Dept Naval Architecture & Ocean Engn 30 Changjeon Dong Pusan 609735 South Korea

The primary advantages of the AHP (adsorption heat pump) including using environmentally friendly working fluids and their capability of using low-grade waste heat as their primary driving energy have raised a great deal of attention in recent years. In this work, computer models of AHPs and the latest relevant findings are reviewed since the performance of an AHP system greatly depends on the coupled heat and mass transfer rates inside the adsorbent bed and the design parameters of the adsorber. The nonlinearity of the coupled heat and mass transfer equations makes the qualitative analysis of such systems difficult and hence many researchers have proposed various models to predict the performance of the system and optimize the design parameters to boost the performance. The available models in the literature have been categorized into thermodynamic models, lumped-parameter models, and distributed-parameter (heat and mass transfer) models. The results of the literature review indicate that recent numerical modeling of AHPs relies on the distributed-parameter models. Majority of the modeling works are focused on validating the proposed model and used the model to optimize the adsorber design parameters and operating conditions of the system. Based on the literature review, some potential future research areas are suggested. (c) 2016 Elsevier Ltd. All rights reserved.

关键词： Numerical simulation Adsorption heat pump distributed-parameter models Coupled heat and mass transfer

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MULTIINPUT, MULTIOUTPUT IDENTIFICATION OF A PILOT-PLANT CLIMBING FILM EVAPORATOR

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CONTROL ENGINEERING PRACTICE 1995年第8期3卷 1067-1073页

作者： YOUNG, BR ALLEN, RM UNIV CANTERBURY DEPT CHEM & PROC ENGNCHRISTCHURCH 1NEW ZEALAND

The major aim of this research was to investigate the modeling and control of a 2.5 kW, 13.6 litres/hour pilot-plant climbing film evaporator concentrating a sodium nitrate solution. This paper reports on a comparison of a range of models of the climbing film evaporator for the specific purpose of developing and designing industrially-viable process control systems. The simplest models of the evaporator were global linear lumped-parameter models. Gain-scheduled linear lumped parameter models were identified to compensate for system non-linearity. Finally, full distributed-parameter models were derived for the evaporator, and their parameters identified.

关键词： SYSTEM IDENTIFICATION MATHEMATICAL MODELING LUMPED-parameter models distributed-parameter models

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TRACER-KINETIC models FOR MEASURING CEREBRAL BLOOD-FLOW USING EXTERNALLY DETECTED RADIOTRACERS

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JOURNAL OF CEREBRAL BLOOD FLOW AND METABOLISM 1987年第4期7卷 443-463页

作者： LARSON, KB MARKHAM, J RAICHLE, ME WASHINGTON UNIV SCH MED INST BIOMED COMP BIOMED COMP LAB 700 S EUCLID AVE ST LOUIS MO 63110 USA WASHINGTON UNIV SCH MED DEPT NEUROL & NEUROSURG SURG ST LOUIS MO 63110 USA WASHINGTON UNIV SCH MED MCDONNELL CTR STUDIES HIGHER BRAIN FUNCT ST LOUIS MO 63110 USA WASHINGTON UNIV SCH MED EDWARD MALLINCKRODT INST RADIOL ST LOUIS MO 63110 USA

All tracer-kinetic models currently employed with positron-emission tomography (PET) are based on compartmental assumptions. Our first indication that a compartmental model might suffer from severe limitations in certain circumstances when used with PET occurred when we implemented the Kety tissue-autoradiography technique for measuring CBF and observed that the resulting CBF estimates, rather than remaining constant (to within predictable statistical uncertainty) as expected, fell with increasing scan duration T when T > 1 min. After ruling out other explanations, we concluded that a one-compartment model does not possess sufficient realism for adequately describing the movement of labeled water in brain. This article recounts our search for more realistic substitute models. We give our derivations and results for the residue-detection impulse responses for unit capillary-tissue systems of our two candidate distributed-parameter models. In a sequence of trials beginning with the simplest, we tested four progressively more detailed candidate models against data from appropriate residue-detection experiments. In these, we generated high-temporal-resolution counting-rate data reflecting the history of radiolabeled-water uptake and washout in the brains of rhesus monkeys. We describe our treatment of the data to yield model-independent empirical values of CBF and of other parameters. By substituting these into our trial-model functions, we were able to make direct comparisons of the model predictions with the experimental dynamic counting-rate histories, confirming that our reservations concerning the one-compartment model were well founded and obliging us to reject two others. We conclude that a two-barrier distributed-parameter model has the potential of serving as a substitute for the Kety model in PET measurements of CBF in patients, especially when scan durations for T > 1 min are desired.

关键词： Cerebral blood flow distributed-parameter models Positron-emission tomography Tissue heterogeneity Tracer kinetics

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On parameter Identification for Complex Biotechnical Systems

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IFAC Proceedings Volumes 1985年第17期18卷 159-165页

作者： A. Munack Institut für Regetungstechnik Universität Hannover Hannover FRG

The parameter identification problem is treated for an SCP process in a tower loop bioreactor (fed batch process). The emphasis is laid on the sensors needed for proper identification of the unknown four parameters in the given model. In particular the following three questions are solved: a)Which types of measurements must be used (dissolved oxygen in liquid phase of the reactor - cell mass - outlet gas analysis), b) how many sensors for dissolved oxygen must be installed, c) where should these sensors be posed along the reactor column? The calculations are based on evaluations of the Fisher information matrix. Identification results are given, based on measurements taken at a bench-scale plant.

关键词： parameter identification tower loop reactors SCP process distributed-parameter models optimal sensor allocation

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