A wavelet collocation method with nonlinear auto companding is proposed for behavioral modeling of switched current circuits.The companding function is automatically constructed according to the initial error distri...A wavelet collocation method with nonlinear auto companding is proposed for behavioral modeling of switched current circuits.The companding function is automatically constructed according to the initial error distribution obtained through approximating the input output function of the SI circuit by conventional wavelet collocation method.In practical applications,the proposed method is a general purpose approach,by which both the small signal effect and the large signal effect are modeled in a unified formulation to ease the process of modeling and simulation.Compared with the published modeling approaches,the proposed nonlinear auto companding method works more efficiently not only in controlling the error distribution but also in reducing the modeling errors.To demonstrate the promising features of the proposed method,several SI circuits are employed as examples to be modeled and simulated.展开更多
A novel behavioral model using three-layer time-delay feed-forward neural networks （TDFFNN）is adopted to model radio frequency （RF）power amplifiers exhibiting memory nonlinearities. In order to extract the paramet...A novel behavioral model using three-layer time-delay feed-forward neural networks （TDFFNN）is adopted to model radio frequency （RF）power amplifiers exhibiting memory nonlinearities. In order to extract the parameters, the back- propagation algorithm is applied to train the proposed neural networks. The proposed model is verified by the typical odd- order-only memory polynomial model in simulation, and the performance is compared with different numbers of taped delay lines（TDLs） and perceptrons of the hidden layer. For validating the TDFFNN model by experiments, a digital test bench is set up to collect input and output data of power amplifiers at a 60 × 10^6 sample/s sampling rate. The 3.75 MHz 16-QAM signal generated in the vector signal generator（VSG） is chosen as the input signal, when measuring the dynamic AM/AM and AM/PM characteristics of power amplifiers. By comparisons and analyses, the presented model provides a good performance in convergence, accuracy and efficiency, which is approved by simulation results and experimental results in the time domain and frequency domain.展开更多
Today’s air combat has reached a high level of uncertainty where continuous or discrete variables with crisp values cannot be properly represented using fuzzy sets. With a set of membership functions, fuzzy logic is ...Today’s air combat has reached a high level of uncertainty where continuous or discrete variables with crisp values cannot be properly represented using fuzzy sets. With a set of membership functions, fuzzy logic is well-suited to tackle such complex states and actions. However, it is not necessary to fuzzify the variables that have definite discrete semantics.Hence, the aim of this study is to improve the level of model abstraction by proposing multiple levels of cascaded hierarchical structures from the perspective of function, namely, the functional decision tree. This method is developed to represent behavioral modeling of air combat systems, and its metamodel,execution mechanism, and code generation can provide a sound basis for function-based behavioral modeling. As a proof of concept, an air combat simulation is developed to validate this method and the results show that the fighter Alpha built using the proposed framework provides better performance than that using default scripts.展开更多
The increasing architecture complexity of data converters makes it necessary to use behavioral models to simulate their electrical performance and to determine their relevant data features. For this purpose, a specifi...The increasing architecture complexity of data converters makes it necessary to use behavioral models to simulate their electrical performance and to determine their relevant data features. For this purpose, a specific data converter simulation environment has been developed which allows designers to perform time-domain behavioral simulations of pipelined analog to digital converters （ADCs）. All the necessary blocks of this specific simulation environment have been implemented using the popular Matlab simulink environment. The purpose of this paper is to present the behavioral models of these blocks taking into account most of the pipelined ADC non-idealities, such as sampling jitter, noise, and operational amplifier parameters （white noise, finite DC gain, finite bandwidth, slew rate, and saturation voltages）. Simulations, using a 10-bit pipelined ADC as a design example, show that in addition to the limits analysis and the electrical features extraction, designers can determine the specifications of the basic blocks in order to meet the given data converter requirements.展开更多
To linearize the multi.band PAs/transmitters, a serial of multi.band predistortion models based on multi.dimensional architecture have been proposed. However, most of these models work properly only for the signals wh...To linearize the multi.band PAs/transmitters, a serial of multi.band predistortion models based on multi.dimensional architecture have been proposed. However, most of these models work properly only for the signals whose harmonic and intermodulation products of carriers' non.overlap with the interested fundamental bands. In this paper, the non.overlapping conditions for dual.band and tri.band signals are derived and denoted in the form of closed.form expression. It can be used to verify whether a given dual.band/multi.band signals can be linearized properly by these multi.dimensional behavioral models. Also the conditions can be used to plan the frequency spacing and maximum bandwidth of a multi.band or non.continuous carrier aggregation signal. Several dual.band and triband signals were tested on the same PA, by employing 2.D DPD and 3.D DPD behavioral models. The measurement results show that the signals which don't satisfy the non.overlapping conditions cannot be linearized well by the multi.dimensional behavioral models which does not take the harmonic and intermodulation products of carriers' into account.展开更多
The pathophysiology of tinnitus is poorly understood and treatments are often unsuccessful. A number of animal models have been developed in order to gain a better understanding of tinnitus. A great deal has been lear...The pathophysiology of tinnitus is poorly understood and treatments are often unsuccessful. A number of animal models have been developed in order to gain a better understanding of tinnitus. A great deal has been learned from these models re- garding the electrophysiological and neuroanatomical correlates of tinnitus following exposure to noise or ototoxic drugs. Re- liable behavioral data is important for determining whether such electrophysiological or neuroanatomical changes are indeed related to tinnitus. Of the many documented tinnitus animal behavioral paradigms, the acoustic startle reflex had been pro- posed as a simple method to identify the presence or absence of tinnitus. Several behavioral models based on conditioned re- sponse suppression paradigms have also been developed. In addition to determining the presence or absence of tinnitus, some of the behavioral paradigms have provided signs of the onset, frequency, and intensity of tinnitus in animals. Although none of these behavioral models have been proved to be a perfect model, these studies provide useful information on understanding the neural mechanisms underlying tinnitus.展开更多
An envelope domain multislice behavioral modeling is introduced. The tradition AM-AM and AM- PM characteristics of power amplifiers axe extended to envelope domain and base-band filter is applied to distortion complex...An envelope domain multislice behavioral modeling is introduced. The tradition AM-AM and AM- PM characteristics of power amplifiers axe extended to envelope domain and base-band filter is applied to distortion complex envelope signal for description of the envelope memory effect. Using traditional one and two-tone tests, the coefficients of nonlinear model and the FIR filter can be extracted. At last the model has been applied to a 10 W WCDMA Power amplifier to predict its output signal. And simulation results show that the model output conforms very well to the traditional transistor level simulation results.展开更多
Voherra series behavioral model for radio frequency （RF） power amplifier （PA） has been widely used in system-level simulation, however, high computational complexity makes this kind of model limited to ＂weak＂ no...Voherra series behavioral model for radio frequency （RF） power amplifier （PA） has been widely used in system-level simulation, however, high computational complexity makes this kind of model limited to ＂weak＂ nonlinearity. In order to reduce the computational complexity and the number of coefficients of Volterra series kernels, a Volterra series improved behavioral model based on Laguerre orthogonal polynomials function, namely Voherra-Laguerre behavioral model, is proposed. Mathematical expressions of Volterra-Laguerre behavioral model is derived, and accuracy of the model is verified through comparison of measured and simulation output data from a freescale PA using MRF21030 transistor. Mathematical analysis and simulation results show that Voherra-Laguerre behavioral model has a simple structure, much less coefficients and better modeling performance than general Volterra series model. The model can be used more correctly for system-level simulation of RF PA with wideband signal.展开更多
With the rapid growth of complexity and functionality of modern electronic systems, creating precise behavioral models of nonlinear circuits has become an attractive topic. Deep neural networks (DNNs) have been recogn...With the rapid growth of complexity and functionality of modern electronic systems, creating precise behavioral models of nonlinear circuits has become an attractive topic. Deep neural networks (DNNs) have been recognized as a powerful tool for nonlinear system modeling. To characterize the behavior of nonlinear circuits, a DNN based modeling approach is proposed in this paper. The procedure is illustrated by modeling a power amplifier (PA), which is a typical nonlinear circuit in electronic systems. The PA model is constructed based on a feedforward neural network with three hidden layers, and then Multisim circuit simulator is applied to generating the raw training data. Training and validation are carried out in Tensorflow deep learning framework. Compared with the commonly used polynomial model, the proposed DNN model exhibits a faster convergence rate and improves the mean squared error by 13 dB. The results demonstrate that the proposed DNN model can accurately depict the input-output characteristics of nonlinear circuits in both training and validation data sets.展开更多
Atomic switches can be used in future nanodevices and to realize conceptually novel electronics in new types of computer architecture because of their simple structure, ease of operation, stability, and reliability. T...Atomic switches can be used in future nanodevices and to realize conceptually novel electronics in new types of computer architecture because of their simple structure, ease of operation, stability, and reliability. The atomic switch is a single solid-state switch with inherent learning abilities that exhibits various nonlinear behaviors with network devices. However, previous studies focused on experiments and nonvolatile memory applications, and studies on the application of the physical properties of the atomic switch in computing were nonexistent. Therefore, we present a simple behavioral model of a molecular gap-type atomic switch that can be included in a simulator. The model was described by three simple equations that reproduced the bistability using a double-well potential and was able to easily be transferred to a simulator using arbitrary numerical values and be integrated into HSPICE. Simulations using the experimental parameters of the proposed atomic switch agreed with the experimental results. This model will allow circuit designers to explore new architectures, contributing to the development of new computing methods.展开更多
In modern broadband communication systems,radio frequency power amplifiers suffer from severe nonlinear distortion and memory effects.To accurately analyze the impact of their characteristics on communication systems,...In modern broadband communication systems,radio frequency power amplifiers suffer from severe nonlinear distortion and memory effects.To accurately analyze the impact of their characteristics on communication systems,it is necessary to establish precise amplifier models.In recent years,deep neural networks have been widely applied to power amplifier modeling.In order to describe the complex dynamic characteristics of power amplifiers,the deep neural network often requires a large number of hidden layers,which leads to large model scale and difficulties in training.To address this issue,a novel behavioral model is proposed in this paper.It combines the classical Saleh model with a deep feedforward neural network.Since the Saleh model can be identified using the least squares method without requiring iterative gradient algorithms,the computational load of model training is significantly reduced.Simulation results demonstrate that,compared to deep neural network models with equivalent parameter quantities,the proposed model exhibits higher accuracy and faster convergence.展开更多
High-voltage and high-power IGBT chips have a noticeable carrier storage effect,which is related to the load current.However,the research on the carrier storage effect of existing IGBT behavior models is insufficient....High-voltage and high-power IGBT chips have a noticeable carrier storage effect,which is related to the load current.However,the research on the carrier storage effect of existing IGBT behavior models is insufficient.In this paper,An improved behavioral model for high-voltage and high-power insulated gate bipolar transistor(IGBT)chips is proposed,which could be used under different load conditions.The problems for applying the traditional behavioral model to more load conditions are discussed.Carrier behavior,in the wide base region,is analyzed,and the analytical expression of the carrierstorage-effect equivalent capacitance and the initial value of the tail current are provided to establish an improved IGBT behavioral model.A corresponding parameter extraction method is proposed.In order to verify the improved behavioral model,an experimental platform is built for resistive load and inductive load,and the results show that the accuracy of the improved behavioral model is much better than that of the traditional model.In addition,the errors of the improved model are within 12.5%under different current and load types.Considering that the maximum error of other models,which could be applied in a variety of load conditions,is more than 25%,the accuracy of the model proposed in this paper is excellent.展开更多
A behavioral model of decision-making is presented to obtain the optimal solution of some economic systems. A numerical example is discussed in detail with what-if and what-for analysis to illustrate the advantages of...A behavioral model of decision-making is presented to obtain the optimal solution of some economic systems. A numerical example is discussed in detail with what-if and what-for analysis to illustrate the advantages of this model.展开更多
Objective:To investigate the impact of health education nursing based on the Transtheoretical Model of Behavior Change on self-efficacy in osteoporosis patients with low bone mass.Methods:A total of 91 osteoporosis pa...Objective:To investigate the impact of health education nursing based on the Transtheoretical Model of Behavior Change on self-efficacy in osteoporosis patients with low bone mass.Methods:A total of 91 osteoporosis patients with low bone mass admitted to our hospital from June 2000 to the end of June 2023 were selected and randomly divided into an observation group and a control group using the envelope method,with 46 and 45 cases in each group,respectively.The control group received routine nursing care,while the observation group received health education nursing based on the Transtheoretical Model of Behavior Change.Bone mineral density(lumbar spine L1-L4,femoral neck),disease awareness(Osteoporosis Knowledge Test Questionnaire,OKT-Q),and self-efficacy(Adult Health Self-Management Skills Rating Scale,AHSMSRS)were compared between the two groups.Results:After the intervention,bone mineral density levels,disease awareness levels,and self-efficacy levels significantly increased in both groups,with the observation group showing greater improvements in all indicators compared to the control group(p<0.05).Conclusion:Interventions based on the Transtheoretical Model of Behavior Change effectively enhance patient self-efficacy and bone health by precisely matching behavioral stages,strengthening social support,and regulating neurobehavioral factors.展开更多
In this paper, an envelope Hammerstein （EH） model is introduced to describe dynamic input -output characteristics of RF power amplifiers. In the modeling approach, we use a new truncation method and an established n...In this paper, an envelope Hammerstein （EH） model is introduced to describe dynamic input -output characteristics of RF power amplifiers. In the modeling approach, we use a new truncation method and an established nonlinear time series method to determine model structure. Then, we discuss the process of model parameter extraction in detailed. Finally, a 2 W WCDMA power amplifier is measured to verify the performance of EH model, and good agreement between model output and measurement result shows our model can accurately predict output characteristic of the power amplifier.展开更多
Objective Patients who experience knee osteoarthritis or chronic knee pain can alleviate their symptoms by performing self-knee massage.Understanding the readiness and types of determinants needed to facilitate self-k...Objective Patients who experience knee osteoarthritis or chronic knee pain can alleviate their symptoms by performing self-knee massage.Understanding the readiness and types of determinants needed to facilitate self-knee massage is needed to design effective,theory-informed interventions.The primary objective of this study was to apply the transtheoretical model of behavior change to identify how factors,which include the type of knee condition and pain level,predict an individual’s readiness to adopt self-knee massage.The secondary objective employed the capability,opportunity and motivation-behavior(COM-B)model to identify relevant determinants that are predictive of an individual’s readiness to undertake self-knee massage.Methods An observational study design was used to recruit individuals with knee osteoarthritis(n=270)and chronic knee pain(n=130).Participants completed an online survey that assessed the transtheoretical model of behavior change stages,COM-B determinants(capability,opportunity and motivation),along with self-administered massage behavior.Multivariate analysis of covariance and structural equation modeling were used to test the primary and secondary objective,respectively.Results Participants who had knee osteoarthritis scored higher on the action stage compared to those with chronic pain(P=0.003),and those who experienced greater level of pain scored higher in the contemplation(P<0.001)and action phases(P<0.001)of performing knee massage compared to those with milder pain.The COM-B structural equation model revealed self-administered knee massage to be predicted by capability(β=0.31,P=0.004)and motivation(β=0.29,P<0.001),but not opportunity(β=–0.10,P=0.39).Pain level predicted motivation(β=0.27,P<0.001),but not capability(β=0.09,P=0.07)or opportunity(β=0.01,P=0.83).Tests for mediating effects found that determinants of COM-B(motivation and capability)mediate between pain level and self-administered massage behavior(β=0.10,P=0.002).Conclusion Clinicians and researchers can expect that patients diagnosed with knee osteoarthritis or who have chronic knee pain are ready(action stage)or are considering the behavior(contemplation stage)of self-knee massage.Individuals who report having knee osteoarthritis or chronic knee pain should be coached to develop the skills to perform self-knee massage and helped to develop the motivation to carry out the therapy.展开更多
Symbolic circuit simulator is traditionally applied to the small-signal analysis of analog circuits. This paper establishes a symbolic behavioral macromodeling method applicable to both small-signal and large-signal a...Symbolic circuit simulator is traditionally applied to the small-signal analysis of analog circuits. This paper establishes a symbolic behavioral macromodeling method applicable to both small-signal and large-signal analysis of general two-stage operational amplifiers （op-amps）. The proposed method creates a two-pole parametric macromodel whose parameters are analytical functions of the circuit element parameters generated by a symbolic circuit simulator. A moment matching technique is used in deriving the analytical model parameter. The created parametric behavioral model can be used for op-amps performance simulation in both frequency and time domains. In particular, the parametric models are highly suited for fast statistical simulation of op-amps in the time-domain. Experiment results show that the statistical distributions of the op-amp slew and settling time characterized by the proposed model agree well with the transistor-level results in addition to achieving significant speedup.展开更多
A behavior model for the receiver of the Ethernet passive optical network（EPON） is presented. The model consists of a fiber, a photodetector, a transimpedance amplifier （TIA） followed by a limiting amplifier and a...A behavior model for the receiver of the Ethernet passive optical network（EPON） is presented. The model consists of a fiber, a photodetector, a transimpedance amplifier （TIA） followed by a limiting amplifier and a clock and data recovery＇ circuit （CDR）. Each sub-model is constructed based on the architecture of a circuit. The noise and jitter in each block such as shot noise, thermal noise, deterministic and random jitter are also considered. The performance of the whole receiver can be evaluated by the simulation of the behavior model, which is faster than the ordinary circuit model and more accurate than the analytical model. The whole model is implemented with C ＋＋ and simulated in Microsoft Visual C ＋＋ 6. 0. Using the Monte Carlo method, the EPON receiver is simulated. The simulation results show a good agreement with experimental ones.展开更多
In this article, the global existence and the large time behavior of smooth solutions to the initial boundary value problem for a degenerate compressible energy transport model are established.
How to fmd main influence factors of individuals to mobile service demand is investiga- ted. The empirical research is conducted in the sample of high-value customers in China mobile market. Based on Lewin behavior mo...How to fmd main influence factors of individuals to mobile service demand is investiga- ted. The empirical research is conducted in the sample of high-value customers in China mobile market. Based on Lewin behavior model, this pa- per establishes factors-matrix from personal and environmental dimensions. Relationships among multiple factors are tested in the structural equa- tion model and their impacts on customers＇ de- mands are elaborated. Findings indicate that opera- tional convenience and business brand image have significant effects on sample users＇ demands. Fur- thermore, annual income, gender, occupation, the needs of access to information and the needs of enriching and improving social relationships are al- so important factors for high-value users. The re- suits may provide further insights into mobile service demand and the model can be popularized to other behavior researches.展开更多
文摘A wavelet collocation method with nonlinear auto companding is proposed for behavioral modeling of switched current circuits.The companding function is automatically constructed according to the initial error distribution obtained through approximating the input output function of the SI circuit by conventional wavelet collocation method.In practical applications,the proposed method is a general purpose approach,by which both the small signal effect and the large signal effect are modeled in a unified formulation to ease the process of modeling and simulation.Compared with the published modeling approaches,the proposed nonlinear auto companding method works more efficiently not only in controlling the error distribution but also in reducing the modeling errors.To demonstrate the promising features of the proposed method,several SI circuits are employed as examples to be modeled and simulated.
基金The National Natural Science Foundation of China(No.60621002)the National High Technology Research and Development Pro-gram of China(863 Program)(No.2007AA01Z2B4).
文摘A novel behavioral model using three-layer time-delay feed-forward neural networks （TDFFNN）is adopted to model radio frequency （RF）power amplifiers exhibiting memory nonlinearities. In order to extract the parameters, the back- propagation algorithm is applied to train the proposed neural networks. The proposed model is verified by the typical odd- order-only memory polynomial model in simulation, and the performance is compared with different numbers of taped delay lines（TDLs） and perceptrons of the hidden layer. For validating the TDFFNN model by experiments, a digital test bench is set up to collect input and output data of power amplifiers at a 60 × 10^6 sample/s sampling rate. The 3.75 MHz 16-QAM signal generated in the vector signal generator（VSG） is chosen as the input signal, when measuring the dynamic AM/AM and AM/PM characteristics of power amplifiers. By comparisons and analyses, the presented model provides a good performance in convergence, accuracy and efficiency, which is approved by simulation results and experimental results in the time domain and frequency domain.
基金This work was supported by the National Natural Science Foundation of China(62003359).
文摘Today’s air combat has reached a high level of uncertainty where continuous or discrete variables with crisp values cannot be properly represented using fuzzy sets. With a set of membership functions, fuzzy logic is well-suited to tackle such complex states and actions. However, it is not necessary to fuzzify the variables that have definite discrete semantics.Hence, the aim of this study is to improve the level of model abstraction by proposing multiple levels of cascaded hierarchical structures from the perspective of function, namely, the functional decision tree. This method is developed to represent behavioral modeling of air combat systems, and its metamodel,execution mechanism, and code generation can provide a sound basis for function-based behavioral modeling. As a proof of concept, an air combat simulation is developed to validate this method and the results show that the fighter Alpha built using the proposed framework provides better performance than that using default scripts.
文摘The increasing architecture complexity of data converters makes it necessary to use behavioral models to simulate their electrical performance and to determine their relevant data features. For this purpose, a specific data converter simulation environment has been developed which allows designers to perform time-domain behavioral simulations of pipelined analog to digital converters （ADCs）. All the necessary blocks of this specific simulation environment have been implemented using the popular Matlab simulink environment. The purpose of this paper is to present the behavioral models of these blocks taking into account most of the pipelined ADC non-idealities, such as sampling jitter, noise, and operational amplifier parameters （white noise, finite DC gain, finite bandwidth, slew rate, and saturation voltages）. Simulations, using a 10-bit pipelined ADC as a design example, show that in addition to the limits analysis and the electrical features extraction, designers can determine the specifications of the basic blocks in order to meet the given data converter requirements.
基金supported by National Key Basic Research Program of China (973 Program) (No.2014CB339900)the National High Technology Research and Development Program of China (863 Program) (No. 2015AA016801)National Natural Science Foundations of China (No.61327806)
文摘To linearize the multi.band PAs/transmitters, a serial of multi.band predistortion models based on multi.dimensional architecture have been proposed. However, most of these models work properly only for the signals whose harmonic and intermodulation products of carriers' non.overlap with the interested fundamental bands. In this paper, the non.overlapping conditions for dual.band and tri.band signals are derived and denoted in the form of closed.form expression. It can be used to verify whether a given dual.band/multi.band signals can be linearized properly by these multi.dimensional behavioral models. Also the conditions can be used to plan the frequency spacing and maximum bandwidth of a multi.band or non.continuous carrier aggregation signal. Several dual.band and triband signals were tested on the same PA, by employing 2.D DPD and 3.D DPD behavioral models. The measurement results show that the signals which don't satisfy the non.overlapping conditions cannot be linearized well by the multi.dimensional behavioral models which does not take the harmonic and intermodulation products of carriers' into account.
基金supported by the grants of the National Key Basic Research Program of China,No.2014CB943001the National Natural Science Foundation of China,Major Project,No.81120108009
文摘The pathophysiology of tinnitus is poorly understood and treatments are often unsuccessful. A number of animal models have been developed in order to gain a better understanding of tinnitus. A great deal has been learned from these models re- garding the electrophysiological and neuroanatomical correlates of tinnitus following exposure to noise or ototoxic drugs. Re- liable behavioral data is important for determining whether such electrophysiological or neuroanatomical changes are indeed related to tinnitus. Of the many documented tinnitus animal behavioral paradigms, the acoustic startle reflex had been pro- posed as a simple method to identify the presence or absence of tinnitus. Several behavioral models based on conditioned re- sponse suppression paradigms have also been developed. In addition to determining the presence or absence of tinnitus, some of the behavioral paradigms have provided signs of the onset, frequency, and intensity of tinnitus in animals. Although none of these behavioral models have been proved to be a perfect model, these studies provide useful information on understanding the neural mechanisms underlying tinnitus.
文摘An envelope domain multislice behavioral modeling is introduced. The tradition AM-AM and AM- PM characteristics of power amplifiers axe extended to envelope domain and base-band filter is applied to distortion complex envelope signal for description of the envelope memory effect. Using traditional one and two-tone tests, the coefficients of nonlinear model and the FIR filter can be extracted. At last the model has been applied to a 10 W WCDMA Power amplifier to predict its output signal. And simulation results show that the model output conforms very well to the traditional transistor level simulation results.
基金Supported by the National Natural Science Foundation of China （No. 60573111 ）
文摘Voherra series behavioral model for radio frequency （RF） power amplifier （PA） has been widely used in system-level simulation, however, high computational complexity makes this kind of model limited to ＂weak＂ nonlinearity. In order to reduce the computational complexity and the number of coefficients of Volterra series kernels, a Volterra series improved behavioral model based on Laguerre orthogonal polynomials function, namely Voherra-Laguerre behavioral model, is proposed. Mathematical expressions of Volterra-Laguerre behavioral model is derived, and accuracy of the model is verified through comparison of measured and simulation output data from a freescale PA using MRF21030 transistor. Mathematical analysis and simulation results show that Voherra-Laguerre behavioral model has a simple structure, much less coefficients and better modeling performance than general Volterra series model. The model can be used more correctly for system-level simulation of RF PA with wideband signal.
文摘With the rapid growth of complexity and functionality of modern electronic systems, creating precise behavioral models of nonlinear circuits has become an attractive topic. Deep neural networks (DNNs) have been recognized as a powerful tool for nonlinear system modeling. To characterize the behavior of nonlinear circuits, a DNN based modeling approach is proposed in this paper. The procedure is illustrated by modeling a power amplifier (PA), which is a typical nonlinear circuit in electronic systems. The PA model is constructed based on a feedforward neural network with three hidden layers, and then Multisim circuit simulator is applied to generating the raw training data. Training and validation are carried out in Tensorflow deep learning framework. Compared with the commonly used polynomial model, the proposed DNN model exhibits a faster convergence rate and improves the mean squared error by 13 dB. The results demonstrate that the proposed DNN model can accurately depict the input-output characteristics of nonlinear circuits in both training and validation data sets.
文摘Atomic switches can be used in future nanodevices and to realize conceptually novel electronics in new types of computer architecture because of their simple structure, ease of operation, stability, and reliability. The atomic switch is a single solid-state switch with inherent learning abilities that exhibits various nonlinear behaviors with network devices. However, previous studies focused on experiments and nonvolatile memory applications, and studies on the application of the physical properties of the atomic switch in computing were nonexistent. Therefore, we present a simple behavioral model of a molecular gap-type atomic switch that can be included in a simulator. The model was described by three simple equations that reproduced the bistability using a double-well potential and was able to easily be transferred to a simulator using arbitrary numerical values and be integrated into HSPICE. Simulations using the experimental parameters of the proposed atomic switch agreed with the experimental results. This model will allow circuit designers to explore new architectures, contributing to the development of new computing methods.
基金supported by the International Education Research Special Project of Zhejiang University of Science and Technology(No.2022IERC005).
文摘In modern broadband communication systems,radio frequency power amplifiers suffer from severe nonlinear distortion and memory effects.To accurately analyze the impact of their characteristics on communication systems,it is necessary to establish precise amplifier models.In recent years,deep neural networks have been widely applied to power amplifier modeling.In order to describe the complex dynamic characteristics of power amplifiers,the deep neural network often requires a large number of hidden layers,which leads to large model scale and difficulties in training.To address this issue,a novel behavioral model is proposed in this paper.It combines the classical Saleh model with a deep feedforward neural network.Since the Saleh model can be identified using the least squares method without requiring iterative gradient algorithms,the computational load of model training is significantly reduced.Simulation results demonstrate that,compared to deep neural network models with equivalent parameter quantities,the proposed model exhibits higher accuracy and faster convergence.
基金This work was supported by the National Natural Science Foundation of China-State Grid Corporation Joint Fund for Smart Grid(No.U1766219).
文摘High-voltage and high-power IGBT chips have a noticeable carrier storage effect,which is related to the load current.However,the research on the carrier storage effect of existing IGBT behavior models is insufficient.In this paper,An improved behavioral model for high-voltage and high-power insulated gate bipolar transistor(IGBT)chips is proposed,which could be used under different load conditions.The problems for applying the traditional behavioral model to more load conditions are discussed.Carrier behavior,in the wide base region,is analyzed,and the analytical expression of the carrierstorage-effect equivalent capacitance and the initial value of the tail current are provided to establish an improved IGBT behavioral model.A corresponding parameter extraction method is proposed.In order to verify the improved behavioral model,an experimental platform is built for resistive load and inductive load,and the results show that the accuracy of the improved behavioral model is much better than that of the traditional model.In addition,the errors of the improved model are within 12.5%under different current and load types.Considering that the maximum error of other models,which could be applied in a variety of load conditions,is more than 25%,the accuracy of the model proposed in this paper is excellent.
基金This work was supported partly by the National Science Foundation 7860024.
文摘A behavioral model of decision-making is presented to obtain the optimal solution of some economic systems. A numerical example is discussed in detail with what-if and what-for analysis to illustrate the advantages of this model.
基金National Key Research and Development Program of China(Project No.:2020YFC2004900)。
文摘Objective:To investigate the impact of health education nursing based on the Transtheoretical Model of Behavior Change on self-efficacy in osteoporosis patients with low bone mass.Methods:A total of 91 osteoporosis patients with low bone mass admitted to our hospital from June 2000 to the end of June 2023 were selected and randomly divided into an observation group and a control group using the envelope method,with 46 and 45 cases in each group,respectively.The control group received routine nursing care,while the observation group received health education nursing based on the Transtheoretical Model of Behavior Change.Bone mineral density(lumbar spine L1-L4,femoral neck),disease awareness(Osteoporosis Knowledge Test Questionnaire,OKT-Q),and self-efficacy(Adult Health Self-Management Skills Rating Scale,AHSMSRS)were compared between the two groups.Results:After the intervention,bone mineral density levels,disease awareness levels,and self-efficacy levels significantly increased in both groups,with the observation group showing greater improvements in all indicators compared to the control group(p<0.05).Conclusion:Interventions based on the Transtheoretical Model of Behavior Change effectively enhance patient self-efficacy and bone health by precisely matching behavioral stages,strengthening social support,and regulating neurobehavioral factors.
文摘In this paper, an envelope Hammerstein （EH） model is introduced to describe dynamic input -output characteristics of RF power amplifiers. In the modeling approach, we use a new truncation method and an established nonlinear time series method to determine model structure. Then, we discuss the process of model parameter extraction in detailed. Finally, a 2 W WCDMA power amplifier is measured to verify the performance of EH model, and good agreement between model output and measurement result shows our model can accurately predict output characteristic of the power amplifier.
基金supported by Dr.Navin Kaushal's lab start-up funding from the School of Health and Human Sciences at Indiana University,Indianapolis.
文摘Objective Patients who experience knee osteoarthritis or chronic knee pain can alleviate their symptoms by performing self-knee massage.Understanding the readiness and types of determinants needed to facilitate self-knee massage is needed to design effective,theory-informed interventions.The primary objective of this study was to apply the transtheoretical model of behavior change to identify how factors,which include the type of knee condition and pain level,predict an individual’s readiness to adopt self-knee massage.The secondary objective employed the capability,opportunity and motivation-behavior(COM-B)model to identify relevant determinants that are predictive of an individual’s readiness to undertake self-knee massage.Methods An observational study design was used to recruit individuals with knee osteoarthritis(n=270)and chronic knee pain(n=130).Participants completed an online survey that assessed the transtheoretical model of behavior change stages,COM-B determinants(capability,opportunity and motivation),along with self-administered massage behavior.Multivariate analysis of covariance and structural equation modeling were used to test the primary and secondary objective,respectively.Results Participants who had knee osteoarthritis scored higher on the action stage compared to those with chronic pain(P=0.003),and those who experienced greater level of pain scored higher in the contemplation(P<0.001)and action phases(P<0.001)of performing knee massage compared to those with milder pain.The COM-B structural equation model revealed self-administered knee massage to be predicted by capability(β=0.31,P=0.004)and motivation(β=0.29,P<0.001),but not opportunity(β=–0.10,P=0.39).Pain level predicted motivation(β=0.27,P<0.001),but not capability(β=0.09,P=0.07)or opportunity(β=0.01,P=0.83).Tests for mediating effects found that determinants of COM-B(motivation and capability)mediate between pain level and self-administered massage behavior(β=0.10,P=0.002).Conclusion Clinicians and researchers can expect that patients diagnosed with knee osteoarthritis or who have chronic knee pain are ready(action stage)or are considering the behavior(contemplation stage)of self-knee massage.Individuals who report having knee osteoarthritis or chronic knee pain should be coached to develop the skills to perform self-knee massage and helped to develop the motivation to carry out the therapy.
文摘Symbolic circuit simulator is traditionally applied to the small-signal analysis of analog circuits. This paper establishes a symbolic behavioral macromodeling method applicable to both small-signal and large-signal analysis of general two-stage operational amplifiers （op-amps）. The proposed method creates a two-pole parametric macromodel whose parameters are analytical functions of the circuit element parameters generated by a symbolic circuit simulator. A moment matching technique is used in deriving the analytical model parameter. The created parametric behavioral model can be used for op-amps performance simulation in both frequency and time domains. In particular, the parametric models are highly suited for fast statistical simulation of op-amps in the time-domain. Experiment results show that the statistical distributions of the op-amp slew and settling time characterized by the proposed model agree well with the transistor-level results in addition to achieving significant speedup.
文摘A behavior model for the receiver of the Ethernet passive optical network（EPON） is presented. The model consists of a fiber, a photodetector, a transimpedance amplifier （TIA） followed by a limiting amplifier and a clock and data recovery＇ circuit （CDR）. Each sub-model is constructed based on the architecture of a circuit. The noise and jitter in each block such as shot noise, thermal noise, deterministic and random jitter are also considered. The performance of the whole receiver can be evaluated by the simulation of the behavior model, which is faster than the ordinary circuit model and more accurate than the analytical model. The whole model is implemented with C ＋＋ and simulated in Microsoft Visual C ＋＋ 6. 0. Using the Monte Carlo method, the EPON receiver is simulated. The simulation results show a good agreement with experimental ones.
基金Supported by the Foundation for Talents of Beijing (20081D0501500171)the Funds of Beijing University of Technology
文摘In this article, the global existence and the large time behavior of smooth solutions to the initial boundary value problem for a degenerate compressible energy transport model are established.
基金supported by the Hunan Province Soft SciencesPlan under Grant No. 2009ZK2001
文摘How to fmd main influence factors of individuals to mobile service demand is investiga- ted. The empirical research is conducted in the sample of high-value customers in China mobile market. Based on Lewin behavior model, this pa- per establishes factors-matrix from personal and environmental dimensions. Relationships among multiple factors are tested in the structural equa- tion model and their impacts on customers＇ de- mands are elaborated. Findings indicate that opera- tional convenience and business brand image have significant effects on sample users＇ demands. Fur- thermore, annual income, gender, occupation, the needs of access to information and the needs of enriching and improving social relationships are al- so important factors for high-value users. The re- suits may provide further insights into mobile service demand and the model can be popularized to other behavior researches.
