The photoplethysmogram(PPG) of a pulse wave,similar in appearance to the arterial blood pressure(ABP) waveform,contains rich information about the cardiovascular system.The decay time constant RC,equal to the product ...The photoplethysmogram(PPG) of a pulse wave,similar in appearance to the arterial blood pressure(ABP) waveform,contains rich information about the cardiovascular system.The decay time constant RC,equal to the product of peripheral resistance R and total arterial compliance C,is a meaningful cardiovascular model parameter in vascular assessment.Using or ameliorating the existing ABP methods does not achieve a satisfactory estimation of RC from the PPG volume pulse(VRC).Thus,a novel non-iterative shape method(NSM) of evaluating VRC is introduced in this paper.The mathematic expression between a novel,readily available morphological parameter called the area difference ratio(ADR) and VRC was established.As it was difficult to calculate VRC from the complicated expression analytically,we recommend estimating it using a piecewise linear interpolation criterion.Also,since the effect of the PPG magnitude is eliminated in the calculation of ADR,precaliberation or normalization is dispensable in the NSM.Results of human experiments indicated that the NSM was computationally efficient,and the simulation experiments confirmed that the NSM was theoretically available for ABP.展开更多
To sustain operation and maintenance of an active distribution network(ADN),a network fee should be charged by the distribution network service provider(DNSP)for facilitating the P2P energy trading service.To this end...To sustain operation and maintenance of an active distribution network(ADN),a network fee should be charged by the distribution network service provider(DNSP)for facilitating the P2P energy trading service.To this end,this paper models the interaction among the DNSP and multiple prosumers as a Stackelberg game,and then develops a non-iterative and decentralized transactive mechanism to simultaneously achieve optimal network utilization pricing and peer-to-peer(P2P)trading.Simulation results in an ADN with four prosumers connected to a common substation bus validate the effectiveness and efficiency of the proposed scheme.展开更多
Parameter estimation of the 2 R-1 C model is usually performed using iterative methods that require high-performance processing units.Consequently,there is a strong motivation to develop less time-consuming and more p...Parameter estimation of the 2 R-1 C model is usually performed using iterative methods that require high-performance processing units.Consequently,there is a strong motivation to develop less time-consuming and more power-efficient parameter estimation methods.Such low-complexity algorithms would be suitable for implementation in portable microcontroller-based devices.In this study,we propose the quadratic interpolation non-iterative parameter estimation(QINIPE)method,based on quadratic interpolation of the imaginary part of the measured impedance,which enables more accurate estimation of the characteristic frequency.The 2 R-1 C model parameters are subsequently calculated from the real and imaginary parts of the measured impedance using a set of closed-form expressions.Comparative analysis conducted on the impedance data of the 2 R-1 C model obtained in both simulation and measurements shows that the proposed QINIPE method reduces the number of required measurement points by 80%in comparison with our previously reported non-iterative parameter estimation(NIPE)method,while keeping the relative estimation error to less than 1%for all estimated parameters.Both non-iterative methods are implemented on a microcontroller-based device;the estimation accuracy,RAM,flash memory usage,and execution time are monitored.Experiments show that the QINIPE method slightly increases the execution time by 0.576 ms(about 6.7%),and requires 24%(1.2 KB)more flash memory and just 2.4%(32 bytes)more RAM in comparison to the NIPE method.However,the impedance root mean square errors(RMSEs)of the QINIPE method are decreased to 42.8%(for the real part)and 64.5%(for the imaginary part)of the corresponding RMSEs obtained using the NIPE method.Moreover,we compared the QINIPE and the complex nonlinear least squares(CNLS)estimation of the 2 R-1 C model parameters.The results obtained show that although the estimation accuracy of the QINIPE is somewhat lower than the estimation accuracy of the CNLS,it is still satisfactory for many practical purposes and its execution time reduces to1/45–1/30.展开更多
This note is concerned with a new direct(non-iterative)method for the solution of an elliptic inverse problem.This method is based on the application of the Green's second identity which leads to a moment problem ...This note is concerned with a new direct(non-iterative)method for the solution of an elliptic inverse problem.This method is based on the application of the Green's second identity which leads to a moment problem for the unknown boundary condition.Tikhonov regularization is used to obtain a stable and close approximation of the missing boundary condition without any need for iterations.Four examples are used to study the applicability of the method with the presence of noise.展开更多
Longitudinal trends of observations can be estimated using the generalized multivariate analysis of variance (GMANOVA) model proposed by [10]. In the present paper, we consider estimating the trends nonparametrically ...Longitudinal trends of observations can be estimated using the generalized multivariate analysis of variance (GMANOVA) model proposed by [10]. In the present paper, we consider estimating the trends nonparametrically using known basis functions. Then, as in nonparametric regression, an overfitting problem occurs. [13] showed that the GMANOVA model is equivalent to the varying coefficient model with non-longitudinal covariates. Hence, as in the case of the ordinary linear regression model, when the number of covariates becomes large, the estimator of the varying coefficient becomes unstable. In the present paper, we avoid the overfitting problem and the instability problem by applying the concept behind penalized smoothing spline regression and multivariate generalized ridge regression. In addition, we propose two criteria to optimize hyper parameters, namely, a smoothing parameter and ridge parameters. Finally, we compare the ordinary least square estimator and the new estimator.展开更多
This paper presents two new non-iterative approximations of the power flow in a network. Real and reactive power are simultaneously modelled in complex equations. Also, resistances are not set to zero. This is a gener...This paper presents two new non-iterative approximations of the power flow in a network. Real and reactive power are simultaneously modelled in complex equations. Also, resistances are not set to zero. This is a generalization of the DC approximation, where only real power is modelled with zero line resistance. Hence the proposed approximations are more accurate than the DC approximation. The voltage lag over a link in a short, low voltage, network link is ten times as accurate as with the DC approximation. In the Appendix a new mathematical constant is introduced.展开更多
基金Project (No.81070885) supported by the National Natural Science Foundation of China
文摘The photoplethysmogram(PPG) of a pulse wave,similar in appearance to the arterial blood pressure(ABP) waveform,contains rich information about the cardiovascular system.The decay time constant RC,equal to the product of peripheral resistance R and total arterial compliance C,is a meaningful cardiovascular model parameter in vascular assessment.Using or ameliorating the existing ABP methods does not achieve a satisfactory estimation of RC from the PPG volume pulse(VRC).Thus,a novel non-iterative shape method(NSM) of evaluating VRC is introduced in this paper.The mathematic expression between a novel,readily available morphological parameter called the area difference ratio(ADR) and VRC was established.As it was difficult to calculate VRC from the complicated expression analytically,we recommend estimating it using a piecewise linear interpolation criterion.Also,since the effect of the PPG magnitude is eliminated in the calculation of ADR,precaliberation or normalization is dispensable in the NSM.Results of human experiments indicated that the NSM was computationally efficient,and the simulation experiments confirmed that the NSM was theoretically available for ABP.
基金supported by Guangdong Basic and Applied Basic Research Foundation under Grant No.2022A1515011035Science and Technology Projects in Guangzhou under Grant No.202201010354National Natural Science Foundation of China(NSFC)under Grant No.51807120.
文摘To sustain operation and maintenance of an active distribution network(ADN),a network fee should be charged by the distribution network service provider(DNSP)for facilitating the P2P energy trading service.To this end,this paper models the interaction among the DNSP and multiple prosumers as a Stackelberg game,and then develops a non-iterative and decentralized transactive mechanism to simultaneously achieve optimal network utilization pricing and peer-to-peer(P2P)trading.Simulation results in an ADN with four prosumers connected to a common substation bus validate the effectiveness and efficiency of the proposed scheme.
基金Project supported by the Ministry of Science and Technology of the Republic of Srpska(No.19/6-020/961-143/18)the EU’s H2020 MSCA MEDLEM(No.690876).
文摘Parameter estimation of the 2 R-1 C model is usually performed using iterative methods that require high-performance processing units.Consequently,there is a strong motivation to develop less time-consuming and more power-efficient parameter estimation methods.Such low-complexity algorithms would be suitable for implementation in portable microcontroller-based devices.In this study,we propose the quadratic interpolation non-iterative parameter estimation(QINIPE)method,based on quadratic interpolation of the imaginary part of the measured impedance,which enables more accurate estimation of the characteristic frequency.The 2 R-1 C model parameters are subsequently calculated from the real and imaginary parts of the measured impedance using a set of closed-form expressions.Comparative analysis conducted on the impedance data of the 2 R-1 C model obtained in both simulation and measurements shows that the proposed QINIPE method reduces the number of required measurement points by 80%in comparison with our previously reported non-iterative parameter estimation(NIPE)method,while keeping the relative estimation error to less than 1%for all estimated parameters.Both non-iterative methods are implemented on a microcontroller-based device;the estimation accuracy,RAM,flash memory usage,and execution time are monitored.Experiments show that the QINIPE method slightly increases the execution time by 0.576 ms(about 6.7%),and requires 24%(1.2 KB)more flash memory and just 2.4%(32 bytes)more RAM in comparison to the NIPE method.However,the impedance root mean square errors(RMSEs)of the QINIPE method are decreased to 42.8%(for the real part)and 64.5%(for the imaginary part)of the corresponding RMSEs obtained using the NIPE method.Moreover,we compared the QINIPE and the complex nonlinear least squares(CNLS)estimation of the 2 R-1 C model parameters.The results obtained show that although the estimation accuracy of the QINIPE is somewhat lower than the estimation accuracy of the CNLS,it is still satisfactory for many practical purposes and its execution time reduces to1/45–1/30.
文摘This note is concerned with a new direct(non-iterative)method for the solution of an elliptic inverse problem.This method is based on the application of the Green's second identity which leads to a moment problem for the unknown boundary condition.Tikhonov regularization is used to obtain a stable and close approximation of the missing boundary condition without any need for iterations.Four examples are used to study the applicability of the method with the presence of noise.
文摘Longitudinal trends of observations can be estimated using the generalized multivariate analysis of variance (GMANOVA) model proposed by [10]. In the present paper, we consider estimating the trends nonparametrically using known basis functions. Then, as in nonparametric regression, an overfitting problem occurs. [13] showed that the GMANOVA model is equivalent to the varying coefficient model with non-longitudinal covariates. Hence, as in the case of the ordinary linear regression model, when the number of covariates becomes large, the estimator of the varying coefficient becomes unstable. In the present paper, we avoid the overfitting problem and the instability problem by applying the concept behind penalized smoothing spline regression and multivariate generalized ridge regression. In addition, we propose two criteria to optimize hyper parameters, namely, a smoothing parameter and ridge parameters. Finally, we compare the ordinary least square estimator and the new estimator.
文摘This paper presents two new non-iterative approximations of the power flow in a network. Real and reactive power are simultaneously modelled in complex equations. Also, resistances are not set to zero. This is a generalization of the DC approximation, where only real power is modelled with zero line resistance. Hence the proposed approximations are more accurate than the DC approximation. The voltage lag over a link in a short, low voltage, network link is ten times as accurate as with the DC approximation. In the Appendix a new mathematical constant is introduced.
