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transfer function model for COVID-19 Deaths in USA Using Case Counts as Input Series

BULLETIN OF THE MALAYSIAN MATHEMATICAL SCIENCES SOCIETY 2022年第SUPPL 1期45卷 461-475页

作者： Shahela, Fahmida Akter Uddin, Nizam Univ Cent Florida Dept Stat & Data Sci Orlando FL 32816 USA

This paper presents a transfer function time series forecast model for COVID-19 deaths using reported COVID-19 case positivity counts as the input series. We have used deaths and case counts data reported by the Center for Disease Control for the USA from July 24 to December 31, 2021. To demonstrate the effectiveness of the proposed transfer function methodology, we have compared some summary results of forecast errors of the fitted transfer function model to those of an adequate autoregressive integrated moving average model and observed that the transfer function model achieved better forecast results than the autoregressive integrated moving average model. Additionally, separate autoregressive integrated moving average models for COVID-19 cases and deaths are also reported.

关键词： ARIMA transfer function model Time series analysis Forecasts COVID-19 cases and deaths Cross-correlations White noise Stationarity Mean absolute error Mean absolute percentage error Root mean square error AIC SBC

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A transfer function model of lighting heat dissipation for detecting time-delay effect and dynamic cooling demand during the real-time operation of buildings

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ENERGY AND BUILDINGS 2022年 254卷 111538-111538页

作者： Li, Ruonan Zhang, Jili Dalian Univ Technol Fac Infrastruct Engn Dalian 116024 Peoples R China

Monitoring real-time heat dissipation of lighting, a major indoor heat source, is essential for determining the dynamic cooling demand of buildings, and it provides a reliable basis for sizing air-conditioning sys-tems and saving energy. Contemporary models cannot be used to obtain the accurate real-time heat dis-sipation of lighting or the time-delay effect, because of which these models have critical limitations in precisely detecting dynamic cooling demand of buildings. To address this problem, a transfer function model is proposed for calculating the real-time heat dissipation of lighting in this paper. First, the model structure is determined according to the energy conservation law, heat transfer principles, and so on. Second, an experiment is conducted using a nearly adiabatic test chamber. Third, parameter identifica-tion and order reduction analyses are performed, and the real-time heat dissipation model of lighting is determined as a third-order transfer function. Experimental data of the same and different types of lighting are employed to verify the proposed model, and the maximum mean absolute percentage error (MAPE) is 7.83%. Comparing with the fixed ratio method, the proposed transfer function model not only reduces MAPE by 66.05% within 1 h after lighting is turned on but also describes a time-delay effect in the stability of lighting heat dissipation. The results of this study exhibit the promising applicability for accu-rately determining the cooling demand of a building during real-time operation, thus improving the indoor thermal environment and reducing energy consumption. (c) 2021 Elsevier B.V. All rights reserved.

关键词： Real-time heat dissipation Lighting transfer function model Nearly adiabatic test chamber

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Visual-vestibular compensation in balance recovery: A transfer function model-based analysis 8th

Visual-vestibular compensation in balance recovery: A transf...

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8th Conference on Foundations of Systems Biology in Engineering (FOBSE)

作者： Voda, Alina Martin, Olivier Neto, Paulo Rodrigues Naves Gascuel, Jean-Dominique Schmerber, Sebastien Univ Grenoble Alpes GIPSA Lab F-38402 St Martin Dheres France Univ Grenoble Alpes CNRS LJK MAVERICK Team St Martin Dheres France Grenoble Univ Hosp NET Clin Grenoble France

During immersive balance rehabilitation, automatic visual-vestibular compensations occurs to reduce the patients' visual reliance and improve the equilibrium. This paper describes the use of an identification procedure to characterise the relationship between visual stimulation features involved in this adaptive sensory compensation, and the balance improvement. The purpose is to determine the stimulus response transfer functions (TF) associated to the equilibrium enhancement. Standing vestibular patients were stimulated by visual virtual flows, whose pattern and speed changed throughout successive stimulation sessions. The analysis of the feet centre-of-pressure, disequilibrium, and identified models parameters for one representative vestibular patient, showed that TF parameters evolved related to the gradual balance recovery boosted by the visual-vestibular compensation. This results suggest that identified TF parameters are suitable indicators for measuring the effect of sensory substitution on equilibrium recovery. This first step to model the relationship between the sensory re-weighting flexibility and the adaptation of postural commands is essential for future clinical studies using identification methods for sensorimotor evaluation in individualized vision-based balance rehabilitation. (C) 2019, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.

关键词： Human balance deficit visual-vestibular compensation virtual reality rehabilitation sensory integration transfer function model adaptive motor control modelling

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Visual-vestibular compensation in balance recovery: A transfer function model-based analysis

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IFAC-PapersOnLine 2019年第26期52卷 88-93页

作者： Alina Voda Olivier Martin Paulo Rodrigues Naves Neto Jean-Dominique Gascuel Sebastien Schmerber GIPSA-lab Univ. Grenoble-Alpes F-38402 Saint Martin d’Hères France MAVERICK team - LJK CNRS Univ. Grenoble-Alpes France Grenoble University Hospital NET clinic Grenoble France

During immersive balance rehabilitation, automatic visual-vestibular compensations occurs to reduce the patients’ visual reliance and improve the equilibrium. This paper describes the use of an identification procedure to characterise the relationship between visual stimulation features involved in this adaptive sensory compensation, and the balance improvement. The purpose is to determine the stimulus-response transfer functions (TF) associated to the equilibrium enhancement. Standing vestibular patients were stimulated by visual virtual flows, whose pattern and speed changed throughout successive stimulation sessions. The analysis of the feet centre-of-pressure, disequilibrium, and identified models parameters for one representative vestibular patient, showed that TF parameters evolved related to the gradual balance recovery boosted by the visual-vestibular compensation. This results suggest that identified TF parameters are suitable indicators for measuring the effect of sensory substitution on equilibrium recovery. This first step to model the relationship between the sensory re-weighting flexibility and the adaptation of postural commands is essential for future clinical studies using identification methods for sensorimotor evaluation in individualized vision-based balance rehabilitation

关键词： Human balance deficit visual-vestibular compensation virtual reality rehabilitation sensory integration transfer function model adaptive motor control modelling

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ARMAX-Based transfer function model Identification Using Wide-Area Measurement for Adaptive and Coordinated Damping Control

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IEEE TRANSACTIONS ON SMART GRID 2017年第3期8卷 1105-1115页

作者： Liu, Hesen Zhu, Lin Pan, Zhuohong Bai, Feifei Liu, Yong Liu, Yilu Patel, Mahendra Farantatos, Evangelos Bhatt, Navin Univ Tennessee Dept Elect Engn & Comp Sci Knoxville TN 37996 USA Southwest Jiaotong Univ Sch Elect Engn Chengdu 610031 Peoples R China Oak Ridge Natl Lab Oak Ridge TN 37831 USA Elect Power Res Inst 3412 Hillview Ave Palo Alto CA 94304 USA

One of the main drawbacks of the existing oscillation damping controllers that are designed based on offline dynamic models is adaptivity to the power system operating condition. With the increasing availability of wide-area measurements and the rapid development of system identification techniques, it is possible to identify a measurement-based transfer function model online that can be used to tune the oscillation damping controller. Such a model could capture all dominant oscillation modes for adaptive and coordinated oscillation damping control. This paper describes a comprehensive approach to identify a low-order transfer function model of a power system using a multi-input multi-output (MIMO) autoregressive moving average exogenous (ARMAX) model. This methodology consists of five steps: 1) input selection;2) output selection;3) identification trigger;4) model estimation;and 5) model validation. The proposed method is validated by using ambient data and ring-down data in the 16-machine 68-bus Northeast Power Coordinating Council system. The results demonstrate that the measurement-based model using MIMO ARMAX can capture all the dominant oscillation modes. Compared with the MIMO subspace state space model, the MIMO ARMAX model has equivalent accuracy but lower order and improved computational efficiency. The proposed model can be applied for adaptive and coordinated oscillation damping control.

关键词： Autoregressive moving average exogenous (ARMAX) correlation coefficient index oscillation damping control subspace state space subspace state-space system identification (N4SID) system identification transfer function model wide-area measurement system (WAMS)

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Evaluation of a transfer function model using experimental data and numerical analysis: the case of a pyroelectric sensor

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JOURNAL OF COMPUTATIONAL ELECTRONICS 2016年第3期15卷 1003-1016页

作者： Sifi, Nejmeddine Jridi, Ahmed Touayar, Oualid Univ Carthage Natl Inst Appl Sci & Technol INSAT Tunis Tunisia INSAT Res Lab Mat Measurements & Applicat BP 676 Tunis 1080 Tunisia

The purpose of this paper is to present an evaluation study of a pyroelectric sensor model implemented in MATLAB (R)/SIMULINK (R) environment. The sensor model consists of some cascaded transfer functions taking into account the material characteristics and geometrical parameters which have been synthesized in the form of thermal and electrical time constants and a global multiplying coefficient. The model was proposed by Odon to serve as an excellent basis for the analysis of the dynamic behavior of a pyroelectric sensor. The study performed is relevant to evaluate the validity of the model by comparing its simulated response to measurement obtained on a pyroelectric sensor prototype. To achieve this evaluation, an optimization algorithm is used to estimate the parameters values of the transfer function model using a succession of tests and adjustments so that the algorithm converges to and reaches the optimal solution giving an acceptable correlation between simulated and measured responses. The semi-experimental evaluation approach has been applied to two prototype sensors with pyroelectric material thicknesses of 9 and 25 mu m, respectively. In the two cases, the estimated values of the parameters were very interesting in terms of uncertainties (between 1.846 and 6.726% at 1 sigma level) and setting evidence for the existence of two global solutions, i.e., two deep minima for each prototype sensor.

关键词： model evaluation transfer function model Pyroelectric sensor Optimization algorithm Measurement

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transfer function modeling and dynamic performance analysis of single-axis acoustic-levitation systems

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MECHATRONICS 2023年第1期92卷

作者： Jiang, Liangxu Wang, Yingwei Fan, Shuyuan Yu, Xiaohui Li, Xinbo Jilin Univ Coll Commun Engn Changchun 130022 Peoples R China

The development of contactless acoustic-levitation technology has grown rapidly in recent years, and the acoustic-levitation system is an electromechanical system with complex dynamics. However, the traditional differential equation model, used as the core basement for the system, is ineffective at describing the effects of structural changes or parameter adjustments on system performance, which is vital for the design and analysis of the system. This paper proposes a transfer function model to solve this issue. The model can characterize the dynamic performance of the system. Meanwhile, it is competent to describe the effects of structural changes or parameter adjustments on system performance because it can directly derive the relationship between the system performance index and the system parameter variation. It simplifies system design and analysis. In the proposed model, the displacement of the acoustic trap and that of the object are considered as the input and output, respectively, clearly demonstrating the relationship between the acoustic-trap movement and the object motion. Based on the model, the time-domain dynamic performance and the frequency-domain characteristics of the system are systematically described. Furthermore, the model describes the effects of the parameters (the stiffness coefficient, levitated objects, and media) adjustments on the time-domain dynamic performance (damped oscillation frequency, rise time, and peak time) and the frequency-domain characteristics (resonance frequency and bandwidth frequency) of the system. The damping oscillation frequency, resonance frequency, and band-width frequency are positively correlated with the stiffness coefficient, while the rise time and peak time are negatively correlated with the stiffness coefficient. These results are verified by numerical simulations and physical experiments. These works will support the design of the acoustic-levitation controller, serve the analysis of the whole system per

关键词： Acoustic levitation transfer function model Dynamic performance Frequency -domain characteristics

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transfer function models for Cylindrical MC Channels With Diffusion and Laminar Flow

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IEEE TRANSACTIONS ON MOLECULAR BIOLOGICAL AND MULTI-SCALE COMMUNICATIONS 2021年第4期7卷 271-287页

作者： Schaefer, Maximilian Wicke, Wayan Brand, Lukas Rabenstein, Rudolf Schober, Robert Friedrich Alexander Univ Erlangen Nurnberg Inst Digital Commun D-91058 Erlangen Germany Friedrich Alexander Univ Erlangen Nurnberg Chair Multimedia Commun & Signal Proc D-91058 Erlangen Germany

The analysis and design of advection-diffusion based molecular communication (MC) systems in cylindrical environments is of particular interest for applications such as micro-fluidics and targeted drug delivery in blood vessels. Therefore, the accurate modeling of the corresponding MC channel is of high importance. The propagation of particles in these systems is caused by a combination of diffusion and flow with a parabolic velocity profile, i.e., laminar flow. The propagation characteristics of the particles can be categorized into three different regimes: The flow dominant regime where the influence of diffusion on the particle transport is negligible, the dispersive regime where diffusion has a much stronger impact than flow, and the mixed regime where both effects are important. For the limiting regimes, i.e., the flow dominant and dispersive regimes, well-known solutions and approximations for particle transport exist. For the mixed regime, approximations, numerical techniques, and particle based simulations are employed. However, the few analytical models that are applicable in all three regimes impose significant constraints on the possible transmitter locations and particle release profiles. In this paper, we develop a more general analytical model for the advection-diffusion problem in cylindrical environments, which is applicable in all three regimes and accounts for general particle release models. The proposed model exhibits a higher accuracy than existing models and is based on a transfer function approach, where the main challenge is the incorporation of laminar flow. The properties of the proposed model are analyzed by numerical evaluation for different scenarios including the uniform and point release of particles. We provide a comparison with particle based simulations and existing analytical models from the literature to demonstrate the validity of the proposed analytical model.

关键词： Molecular communication transfer function model channel model Poiseuille flow

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Assessment of rainfall-runoff time series data using transfer function modelling with exogenous variable

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INTERNATIONAL JOURNAL OF HYDROLOGY SCIENCE AND TECHNOLOGY 2022年第1期14卷 47-62页

作者： Taghadomi, Homa Jalaeian Wang, Xixi Erten-Unal, Mujde Vazifedan, Turaj Old Dominion Univ Dept Civil & Environm Engn Norfolk VA 23529 USA Eastern Virginia Medial Sch Dept Paediat Div Biostat & Innovat Res Norfolk VA USA

This study assesses the rainfall-runoff time series data using a transform function approach. modelling rainfall-runoff data is crucial in the hydrology and water resource management. However, the characteristics of serial and cross-correlation between runoff and rainfall sequences have not been discussed widely in the literature. This study evaluates the performance of the transfer function method in modelling monthly rainfall-runoff data in the Blackwater River watershed located in coastal Virginia. Maximum likelihood estimation was employed for estimating the model's parameters. Different performance evaluation criteria (AIC, AICC, BIC, RMSE and MASE) were employed for model selection. The adequacy of the final transfer function model was evaluated by Dickey-Fuller, KPSS, Ljung-Box. Moreover, the performance of the final model was compared with the simplest time series models to justify the complexity of the model. This study is the first achievement of the hydrological response to precipitation and temperature over the Blackwater River watershed.

关键词： rainfall runoff temperature transfer function model exogenous variable ARIMAX seasonal Dickey-Fuller KPSS Ljung-Box Blackwater River

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Polynomial and transfer function models for multi input single output (MISO) PEM fuel cell by system identification methodology

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INTERNATIONAL JOURNAL OF AMBIENT ENERGY 2021年第1期43卷 4623-4628页

作者： Chavan, Sudarshan L. JSPMs Rajarshi Shahu Coll Engn Dept Elect Engn Pune Maharashtra India

Mathematical modelling is the tool to reveal and fully understand the input output relationship in most of the dynamic systems including fuel cells. The dynamic behaviour of fuel cell system is determined by a set of system processes and every process is characterised by its physical, mechanical or chemical properties, which are not readily known. A fuel cell system model always tries to find important aspects related to its dynamic behaviour. Due to the complex internal structure of Polymer Electrolyte Membrane (PEM) fuel cell, it is not so easy to set its internal and external parameters for its optimum performance and hence an advance modelling method need to be apply to analyse and optimise its dynamic performance. In this paper, most simplified autoregressive polynomial and transfer function models for a multi-input single output PEM fuel cell is presented using the system identification black box methodology. Simulated data of both the developed models are validated with the experimentally measured data from a practical PEM fuel cell. The accuracy of both the developed models is more than 95% and therefore the developed models can be used to analyse the performance of PEM fuel cell at any loading condition.

关键词： PEM fuel cell autoregressive polynomial model transfer function model system identification black box model

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