In this paper,we propose a novel probabilistic method for predicting the undrained bearing capacity of spatially variable soils.Our approach combines a Gaussian process regression(GPR)-based surrogate model with rando...In this paper,we propose a novel probabilistic method for predicting the undrained bearing capacity of spatially variable soils.Our approach combines a Gaussian process regression(GPR)-based surrogate model with random cell-based smoothed finite analysis.The Gaussian process emulator(GPE)serves as a statistical tool for making predictions from a data set.First,we validate the accuracy and efficiency of kinematic limit analysis using the cell-based smoothed finite element method(CS-FEM)against the standard finite element method(FEM)and edge-based smoothed FEM(ES-FEM).The numerical results demonstrate that the CS-FEM framework surpasses traditional numerical approaches,establishing its reliability in computing collapse loads.Subsequently,we conduct several hundred simulations to develop a surrogate model for predicting the undrained bearing capacity of shallow foundations.By utilizing various kernel functions,we enhance the accuracy of the GPE in these predictions.This method offers a practical and efficient solution,effectively addressing multiple uncertainties.Numerical results indicate that the GPE significantly boosts computational efficiency,achieving satisfactory outcomes within minutes compared to the days required for conventional simulations.Notably,the mean absolute percentage error(MAPE)decreases from 2.38%to 1.82%for rough foundations when employing Matérn and rational quadratic kernel functions,respectively.Additionally,combining different kernel functions further enhances the accuracy of collapse load predictions.展开更多
The proliferation of heterogeneous networks,such as the Internet of Things(IoT),unmanned aerial vehicle(UAV)networks,and edge networks,has increased the complexity of network operation and administration,driving the e...The proliferation of heterogeneous networks,such as the Internet of Things(IoT),unmanned aerial vehicle(UAV)networks,and edge networks,has increased the complexity of network operation and administration,driving the emergence of digital twin networks(DTNs)that create digital-physical network mappings.While DTNs enable performance analysis through emulation testbeds,current research focuses on network-level systems,neglecting equipment-level emulation of critical components like core switches and routers.To address this issue,we propose v Fabric(short for virtual switch),a digital twin emulator for high-capacity core switching equipment.This solution implements virtual switching and network processor(NP)chip models through specialized processes,deployable on single or distributed servers via socket communication.The v Fabric emulator can realize the accurate emulation for the core switching equipment with 720 ports and 100 Gbit/s per port on the largest scale.To our knowledge,this represents the first digital twin emulation framework specifically designed for large-capacity core switching equipment in communication networks.展开更多
Post-quantum transport layer security(PQ-TLS)is capable of effectively defending against quantum threats to current network communications,whereas its larger public key and certificate sizes as well as higher computat...Post-quantum transport layer security(PQ-TLS)is capable of effectively defending against quantum threats to current network communications,whereas its larger public key and certificate sizes as well as higher computational overhead may result in a significant performance reduction compared with conventional TLS.In this paper,we present a systematic evaluation of PQ-TLS performance across diverse deployment scenarios to address the following critical research questions.(1)What is the performance behavior of PQ-TLS across different TLS modes?(2)How does PQ-TLS perform across varying client scales?(3)Which network topology is most suitable for PQ-TLS?(4)How does PQ-TLS perform on personal computers(PCs)compared to embedded IoT devices?To the best of our knowledge,this is the first work to comprehensively address these issues,offering implementers some insights into PQ-TLS performance and guidance for optimizing it across diverse scenarios.展开更多
Orthogonal Frequency Division Multiplexing(OFDM)enables efficient Dynamic Spectrum Access(DSA)but suffers from high sidelobe that causes excessive out-of-band(OOB)emissions and expose the system to spectrum-layer cybe...Orthogonal Frequency Division Multiplexing(OFDM)enables efficient Dynamic Spectrum Access(DSA)but suffers from high sidelobe that causes excessive out-of-band(OOB)emissions and expose the system to spectrum-layer cyberattacks such as man-in-the-middle(MITM),eavesdropping,and primary user emulation(PUE)attacks.To address both spectral leakage and its security implications,this paper introduces a secure and intelligent hybrid optimization strategy that combinesan Eigenspace-based Generalized Sidelobe Canceller(ES-GSC)with a Genetic Algorithm(GA),to derive optimally weighted cancellation carriers.The proposed method jointly suppresses sidelobes and reinforces resistance to leakage-based attacks.MATLAB Simulation demonstrate considerable reductions in OOB emissions and higher resilience against spectrum-layer threats compared with existing techniques.展开更多
Background:Most sepsis patients develop sepsis-associated acute kidney injury(SA-AKI),which poses a significant threat to survival and lacks specific treatment.To date,there are no published randomized controlled tria...Background:Most sepsis patients develop sepsis-associated acute kidney injury(SA-AKI),which poses a significant threat to survival and lacks specific treatment.To date,there are no published randomized controlled trials that have established a link between albumin use and SA-AKI development in sepsis.Therefore,it is unclear whether albumin use may influence the risk of SA-AKI.Methods:The present study employed a target trial emulation using observational data to track adult sepsis patients initially admitted to the intensive care unit at Beth Israel Deaconess Medical Center,Boston,Massachusetts,for a period of 7 d from 2008 to 2022.Immortal time bias was controlled using the clone-censor-weight(CCW)method,along with a new-user design to address current user bias.The exposure variable was the early administration of albumin following the onset of sepsis.Based on albumin use,patients were classified into two groups:the albumin group(n=27,088)and the no albumin group(n=27,088).The primary outcome was the development of SA-AKI,and the secondary outcome was 7-day all-cause mortality.The primary outcome was analyzed using competing risk analyses.Furthermore,sensitivity and subgroup analyses were also performed.Results:Among the 27,088 patients analyzed,albumin administration was associated with a significantly higher SA-AKI risk(relative difference=3.47%,95%CI 1.76-5.23)compared to non-administration.There was no clinically meaningful difference in 7-day survival(relative difference=0.05%,95%CI-2.30 to 2.45).Sensitivity analyses consistently supported these results.All these analyses were conducted on data that were collected after CCW.Conclusions:Early albumin administration may increase the risk of SA-AKI in sepsis patients without conferring a short-term survival benefit.These results underscore the need for a rigorous risk-benefit assessment when incorporating albumin into sepsis resuscitation protocols and highlight the need for further clinical validation.However,it is important to exercise caution when interpreting the conclusions of this study,given its exploratory and preliminary nature.展开更多
Multi-organ-on-a-chip(MOOC)technology represents a pivotal direction in the organ-on-a-chip field,seeking to emulate the complex interactions of multiple human organs in vitro through microfluidic systems.This technol...Multi-organ-on-a-chip(MOOC)technology represents a pivotal direction in the organ-on-a-chip field,seeking to emulate the complex interactions of multiple human organs in vitro through microfluidic systems.This technology overcomes the limitations of traditional single-organ models,providing a novel platform for investigating complex disease mechanisms and evaluating drug efficacy and toxicity.Although it demonstrates broad application prospects,its development still faces critical bottlenecks,including inadequate physiological coupling between organs,short functional maintenance durations,and limited real-time monitoring capabilities.Contemporary research is advancing along three key directions,including functional coupling,sensor integration,and full-process automation systems,to propel the technology toward enhanced levels of physiological relevance and predictive accuracy.展开更多
We present a computer-modeling framework for photovoltaic(PV)source emulation that preserves the exact single-diode physics while enabling iteration-free,real-time evaluation.We derive two closed-form explicit solvers...We present a computer-modeling framework for photovoltaic(PV)source emulation that preserves the exact single-diode physics while enabling iteration-free,real-time evaluation.We derive two closed-form explicit solvers based on the Lambert W function:a voltage-driven V-Lambert solver for high-fidelity I–V computation and a resistance-driven R-Lambert solver designed for seamless integration in a closed-loop PV emulator.Unlike Taylor-linearized explicit models,our proposed formulation retains the exponential nonlinearity of the PV equations.It employs a numerically stable analytical evaluation that eliminates the need for lookup tables and root-finding,all while maintaining limited computational costs and a small memory footprint.The R-Lambert model is integrated into a buck-converter emulator equipped with a discrete PI regulator,which generates current references directly from sensed operating points,thus supporting hardware-constrained implementation.Comprehensive numerical experiments conducted on six commercial modules from various technologies(mono,poly,and multicrystalline)demonstrate significant accuracy improvements under the IEC EN 50530 near-MPP criterion:the V-Lambert solver reduces the±10%Vmpp band error by up to 61 times compared to an explicit-model baseline.Dynamic simulations under varying irradiance,temperature,and load conditions achieve millisecond-scale settling with accurate trajectory tracking.Additionally,processor-in-the-loop experimental validation on an embedded microcontroller supports the simulation results.By unifying exact analytical modeling with embedded realization,this work advances computer modeling for PV emulation,MPPT benchmarking,and controller verification in integrated renewable energy systems.展开更多
In this paper a fuel cell emulator model suitable for each fuel cell type and power level is proposed. A power interface to the electronic load and a digital section are provided. The fuel cell steady-state, dynamic a...In this paper a fuel cell emulator model suitable for each fuel cell type and power level is proposed. A power interface to the electronic load and a digital section are provided. The fuel cell steady-state, dynamic and thermal behaviour is modeled by the digital controller. The emulator architecture is deeply analyzed and remarks on hardware implementation algorithms are provided for further applications. The system is tested on a 10 W Proton Exchange Membrane （PEM） fuel cell and the high accuracy of the proposed emulator is shown by the comparison between experimental and simulation results.展开更多
In this paper,the transmission performances are studied in cognitive radio networks with primary user emulator and relay existence.In the proposed network,the users include primary users,secondary users and primary us...In this paper,the transmission performances are studied in cognitive radio networks with primary user emulator and relay existence.In the proposed network,the users include primary users,secondary users and primary user emulators.The decreasing access priority of the users are primary users,primary user emulators and secondary users.Different user access to the network results in different transmission effects.We impose interference power constraints on the secondary users to protect the primary users from being interfered.We also adopt the transmission mechanism that transits among more than one secondary transmitters,secondary receivers and relays.The transition models of the transmission states are proposed to describe the transmission mechanism.To investigate the transmission performances,the theory of effective capacity is adopted.The transmission performances in terms of effective capacity are expressed and demonstrated under different transmission policies.The overall effective capacity,as the overall data traffic in the cognitive radio network,is calculated.Besides,the overall effective capacity is demonstrated under different transmission strategies.The results show the greedy transmission strategy outperforms the rest of the transmission 8 policies in the overall effective capacity.For a larger number of the users,the effective capacity converges to a certain value.展开更多
The mathematical physics model of mine methane and coal dust explosion propagation was established in the research,by using continuous phase,combustion,par- ticulate equations of mathematical physics.Based upon the da...The mathematical physics model of mine methane and coal dust explosion propagation was established in the research,by using continuous phase,combustion,par- ticulate equations of mathematical physics.Based upon the data from mine methane drainage roadway explosion,and mine methane and coal dust explosion propagation ex- perimental studies,the numerical emulator system of mine methane and coal dust explo- sion software was developed by using prevalent flow simulation platform,which can be used to simulate the explosion accidents process effectively.In addition,the system can also be used to determine whether coal dust involved in the explosion,and to simulate accurately the transition from deflagration to detonation in methane explosion,propagation velocity of explosion shock,attenuation pattern,and affected area of explosion.展开更多
As commercial memristors are still unavailable in the market, mathematic models and emulators which can imitate the features of the mernristor are meaningful for further research. In this paper, based on the analyses ...As commercial memristors are still unavailable in the market, mathematic models and emulators which can imitate the features of the mernristor are meaningful for further research. In this paper, based on the analyses of characteristics of the q-φ curve, an exponential flux-controlled model, which has the quality that its memductance （memristance） will keep monotonically increasing or decreasing unless the voltage＇s polarity reverses （if not approach the boundaries）, is constructed. A new approach to designing the floating emulator of the memristor is also proposed. This floating structure can flexibly meet various demands for the current through the memristor （especially the demand for a larger current）. The simulations and experiments are presented to confirm the effectiveness of this model and its floating emulator.展开更多
Power system inherently consists of capacitance and inductance in its components. Equipment with saturable inductance and circuit capacitance provides circumstances of generating ferroresonance, resulting in overvolta...Power system inherently consists of capacitance and inductance in its components. Equipment with saturable inductance and circuit capacitance provides circumstances of generating ferroresonance, resulting in overvoltage and overcurrent in the connected system. The effects of ferroresonance result in insulation failure and hence damage to the equipment is unavoidable. Though many devices are proposed for mitigating such circumstances, a promising technology of using memristors may provide better performance than others in the future. A memristor emulator using the N-channel JFET J310 is used in this work. Unlike other electronic components that replicate memristor properties, the chosen memristor emulator is a passive device since it does not need any external power supply. Simulation and experimental results verify the design of a memristor emulator and the characteristics of an ideal memristor. Experimental results prove that the memristor emulator can suppress the fundamental ferroresonance induced in a prototype single phase transformer. The results of the harmonic analysis also validate the memristor performance against the conventional technique.展开更多
This paper presents the modeling, simulation and practical implementation of an inverter-based diesel generator emulator. The main purpose of this emulator is for the study of frequency variations in diesel-based auto...This paper presents the modeling, simulation and practical implementation of an inverter-based diesel generator emulator. The main purpose of this emulator is for the study of frequency variations in diesel-based autonomous power systems in a laboratory environment where the operation of a real diesel generator is not possible. The emulator basically consists in a voltage source inverter with a second order output filter which voltage references are given by the model of the diesel generator. The control of the emulator is based on the digital signal processor TMS320F2812, where the mathematical models of the diesel generator and the control of the inverter are computed in real-time. Parameters for the model were obtained from commercially available components. Experimental results for different values of speed droop showed that the emulator achieves a satisfactory performance in the transient and stationary response. For the stationary response, the measured frequency deviates from theoretical values with a mean absolute error of: 0.06 Hz for 0% droop, 0.037 Hz for 3% droop, and 0.087 Hz for 5% droop. For the transient response, the measured frequency nadir deviates from simulations in: 0.05 Hz for 0% droop, 0.02 Hz for 3% droop, and 0.1 Hz for 5% droop.展开更多
This paper investigates the subjective assessment of QoE of web and video services over a mobile network. To achieve this, the authors used the network emulator (NetEm) traffic control functionality to simulate the dy...This paper investigates the subjective assessment of QoE of web and video services over a mobile network. To achieve this, the authors used the network emulator (NetEm) traffic control functionality to simulate the dynamic behaviour of a mobile network. Experiments were conducted in a laboratory setting and test conditions were varied to ascertain the QoE, with a focus on QoE metrics such as delay and packet loss ratio. From the experiments conducted, it was observed that there was a negative correlation between delay and average mean opinion score (MOS), and between packet loss ratio and average MOS. The results obtained can be adopted by network operators to provide better services which would lead to improved subscriber base and profitability for the operators and better QoE for the end users.展开更多
This work aims at developing an automatic system for the control of the APS （air plasma spraying） plasma process in which some instability phenomena are present. APS is a versatile technique to produce coatings of p...This work aims at developing an automatic system for the control of the APS （air plasma spraying） plasma process in which some instability phenomena are present. APS is a versatile technique to produce coatings of powder material at high deposition rates. Using this technique, powder particles are injected into a plasma jet, where they are melted and accelerated towards a substrate. The coating microstructures and properties depend strongly on the characteristics of the plasma jet, which can be controlled by the adjustment of the process parameters. However, the imeractions among the spray variables, render optimization and control of this process are quite complex. Understanding relationships between coating properties and process parameters is mandatory to optimize the process technique and the product quality. We are interested in this work to build an on-line control model for the APS process based on the elements of artificial intelligence and to build an emulator that replicates the dynamic behavior of the process as closely as possible.展开更多
Emulating massively parallel computer architectures represents a very important tool for the parallel programmers. It allows them to implement and validate their algorithms. Due to the high cost of the massively paral...Emulating massively parallel computer architectures represents a very important tool for the parallel programmers. It allows them to implement and validate their algorithms. Due to the high cost of the massively parallel real machines, they remain unavailable and not popular in the parallel computing community. The goal of this paper is to present an elaborated emulator of a 2-D massively parallel re-configurable mesh computer of size n x n processing elements (PE). Basing on the object modeling method, we develop a hard kernel of a parallel virtual machine in which we translate all the physical properties of its different components. A parallel programming language and its compiler are also devel-oped to edit, compile and run programs. The developed emulator is a multi platform system. It can be installed in any sequential computer whatever may be its operating system and its processing unit technology (CPU). The size n x n of this virtual re-configurable mesh is not limited;it depends just on the performance of the sequential machine supporting the emulator.展开更多
In this paper, multimodel and neural emulators are proposed for uncoupled multivariable nonlinear plants with unknown dynamics. The contributions of this paper are to extend the emulators to multivariable non square s...In this paper, multimodel and neural emulators are proposed for uncoupled multivariable nonlinear plants with unknown dynamics. The contributions of this paper are to extend the emulators to multivariable non square systems and to propose a systematic method to compute the multimodel synthesis parameters. The effectiveness of the proposed emulators is shown through two simulation examples. The obtained results are very satisfactory, they illustrate the performance of both emulators and show the advantages of the multimodel emulator relatively to the neural one.展开更多
To study the uncertainty quantification of resonant states in open quantum systems,we developed a Bayesian framework by integrating a reduced basis method(RBM)emulator with the Gamow coupled-channel(GCC)approach.The R...To study the uncertainty quantification of resonant states in open quantum systems,we developed a Bayesian framework by integrating a reduced basis method(RBM)emulator with the Gamow coupled-channel(GCC)approach.The RBM,constructed via eigenvector continuation and trained on both bound and resonant configurations,enables the fast and accurate emulation of resonance properties across the parameter space.To identify the physical resonant states from the emulator’s output,we introduce an overlap-based selection technique that effectively isolates true solutions from background artifacts.By applying this framework to unbound nucleus ^(6)Be,we quantified the model uncertainty in the predicted complex energies.The results demonstrate relative errors of 17.48%in the real part and 8.24%in the imaginary part,while achieving a speedup of four orders of magnitude compared with the full GCC calculations.To further investigate the asymptotic behavior of the resonant-state wavefunctions within the RBM framework,we employed a Lippmann–Schwinger(L–S)-based correction scheme.This approach not only improves the consistency between eigenvalues and wavefunctions but also enables a seamless extension from real-space training data to the complex energy plane.By bridging the gap between bound-state and continuum regimes,the L–S correction significantly enhances the emulator’s capability to accurately capture continuum structures in open quantum systems.展开更多
文摘In this paper,we propose a novel probabilistic method for predicting the undrained bearing capacity of spatially variable soils.Our approach combines a Gaussian process regression(GPR)-based surrogate model with random cell-based smoothed finite analysis.The Gaussian process emulator(GPE)serves as a statistical tool for making predictions from a data set.First,we validate the accuracy and efficiency of kinematic limit analysis using the cell-based smoothed finite element method(CS-FEM)against the standard finite element method(FEM)and edge-based smoothed FEM(ES-FEM).The numerical results demonstrate that the CS-FEM framework surpasses traditional numerical approaches,establishing its reliability in computing collapse loads.Subsequently,we conduct several hundred simulations to develop a surrogate model for predicting the undrained bearing capacity of shallow foundations.By utilizing various kernel functions,we enhance the accuracy of the GPE in these predictions.This method offers a practical and efficient solution,effectively addressing multiple uncertainties.Numerical results indicate that the GPE significantly boosts computational efficiency,achieving satisfactory outcomes within minutes compared to the days required for conventional simulations.Notably,the mean absolute percentage error(MAPE)decreases from 2.38%to 1.82%for rough foundations when employing Matérn and rational quadratic kernel functions,respectively.Additionally,combining different kernel functions further enhances the accuracy of collapse load predictions.
基金supported in part by the National Natural Science Foundation of China(NSFC)under Grant Nos.62171085,62272428,62001087,U20A20156,and 61871097the ZTE Industry-University-Institute Cooperation Funds under Grant No.HC-CN-20220722010。
文摘The proliferation of heterogeneous networks,such as the Internet of Things(IoT),unmanned aerial vehicle(UAV)networks,and edge networks,has increased the complexity of network operation and administration,driving the emergence of digital twin networks(DTNs)that create digital-physical network mappings.While DTNs enable performance analysis through emulation testbeds,current research focuses on network-level systems,neglecting equipment-level emulation of critical components like core switches and routers.To address this issue,we propose v Fabric(short for virtual switch),a digital twin emulator for high-capacity core switching equipment.This solution implements virtual switching and network processor(NP)chip models through specialized processes,deployable on single or distributed servers via socket communication.The v Fabric emulator can realize the accurate emulation for the core switching equipment with 720 ports and 100 Gbit/s per port on the largest scale.To our knowledge,this represents the first digital twin emulation framework specifically designed for large-capacity core switching equipment in communication networks.
基金Special Fund for Key Technologies in Blockchain of Shanghai Scientific and Technological Committee(23511100300)。
文摘Post-quantum transport layer security(PQ-TLS)is capable of effectively defending against quantum threats to current network communications,whereas its larger public key and certificate sizes as well as higher computational overhead may result in a significant performance reduction compared with conventional TLS.In this paper,we present a systematic evaluation of PQ-TLS performance across diverse deployment scenarios to address the following critical research questions.(1)What is the performance behavior of PQ-TLS across different TLS modes?(2)How does PQ-TLS perform across varying client scales?(3)Which network topology is most suitable for PQ-TLS?(4)How does PQ-TLS perform on personal computers(PCs)compared to embedded IoT devices?To the best of our knowledge,this is the first work to comprehensively address these issues,offering implementers some insights into PQ-TLS performance and guidance for optimizing it across diverse scenarios.
文摘Orthogonal Frequency Division Multiplexing(OFDM)enables efficient Dynamic Spectrum Access(DSA)but suffers from high sidelobe that causes excessive out-of-band(OOB)emissions and expose the system to spectrum-layer cyberattacks such as man-in-the-middle(MITM),eavesdropping,and primary user emulation(PUE)attacks.To address both spectral leakage and its security implications,this paper introduces a secure and intelligent hybrid optimization strategy that combinesan Eigenspace-based Generalized Sidelobe Canceller(ES-GSC)with a Genetic Algorithm(GA),to derive optimally weighted cancellation carriers.The proposed method jointly suppresses sidelobes and reinforces resistance to leakage-based attacks.MATLAB Simulation demonstrate considerable reductions in OOB emissions and higher resilience against spectrum-layer threats compared with existing techniques.
基金supported by grants from the National Institute of Biomedical Imaging and Bioengineering(NIBIB)of the National Institutes of Health(NIH)under award numbers R01-EB001659(2003-2013)and R01-EB017205(2014-2018)approved by the Institutional Review Boards of Beth Israel Deaconess Medical Center(Boston,MA)and the Massachusetts Institute of Technology(Cambridge,MA).
文摘Background:Most sepsis patients develop sepsis-associated acute kidney injury(SA-AKI),which poses a significant threat to survival and lacks specific treatment.To date,there are no published randomized controlled trials that have established a link between albumin use and SA-AKI development in sepsis.Therefore,it is unclear whether albumin use may influence the risk of SA-AKI.Methods:The present study employed a target trial emulation using observational data to track adult sepsis patients initially admitted to the intensive care unit at Beth Israel Deaconess Medical Center,Boston,Massachusetts,for a period of 7 d from 2008 to 2022.Immortal time bias was controlled using the clone-censor-weight(CCW)method,along with a new-user design to address current user bias.The exposure variable was the early administration of albumin following the onset of sepsis.Based on albumin use,patients were classified into two groups:the albumin group(n=27,088)and the no albumin group(n=27,088).The primary outcome was the development of SA-AKI,and the secondary outcome was 7-day all-cause mortality.The primary outcome was analyzed using competing risk analyses.Furthermore,sensitivity and subgroup analyses were also performed.Results:Among the 27,088 patients analyzed,albumin administration was associated with a significantly higher SA-AKI risk(relative difference=3.47%,95%CI 1.76-5.23)compared to non-administration.There was no clinically meaningful difference in 7-day survival(relative difference=0.05%,95%CI-2.30 to 2.45).Sensitivity analyses consistently supported these results.All these analyses were conducted on data that were collected after CCW.Conclusions:Early albumin administration may increase the risk of SA-AKI in sepsis patients without conferring a short-term survival benefit.These results underscore the need for a rigorous risk-benefit assessment when incorporating albumin into sepsis resuscitation protocols and highlight the need for further clinical validation.However,it is important to exercise caution when interpreting the conclusions of this study,given its exploratory and preliminary nature.
基金supported by the Shenzhen Medical Research Fund(Grant No.A2303049)Guangdong Basic and Applied Basic Research(Grant No.2023A1515010647)+1 种基金National Natural Science Foundation of China(Grant No.22004135)Shenzhen Science and Technology Program(Grant No.RCBS20210706092409020,GXWD20201231165807008,20200824162253002).
文摘Multi-organ-on-a-chip(MOOC)technology represents a pivotal direction in the organ-on-a-chip field,seeking to emulate the complex interactions of multiple human organs in vitro through microfluidic systems.This technology overcomes the limitations of traditional single-organ models,providing a novel platform for investigating complex disease mechanisms and evaluating drug efficacy and toxicity.Although it demonstrates broad application prospects,its development still faces critical bottlenecks,including inadequate physiological coupling between organs,short functional maintenance durations,and limited real-time monitoring capabilities.Contemporary research is advancing along three key directions,including functional coupling,sensor integration,and full-process automation systems,to propel the technology toward enhanced levels of physiological relevance and predictive accuracy.
基金funded by Scientific Research Deanship at University of Ha’il-Saudi Arabia through project number(RG-24014).
文摘We present a computer-modeling framework for photovoltaic(PV)source emulation that preserves the exact single-diode physics while enabling iteration-free,real-time evaluation.We derive two closed-form explicit solvers based on the Lambert W function:a voltage-driven V-Lambert solver for high-fidelity I–V computation and a resistance-driven R-Lambert solver designed for seamless integration in a closed-loop PV emulator.Unlike Taylor-linearized explicit models,our proposed formulation retains the exponential nonlinearity of the PV equations.It employs a numerically stable analytical evaluation that eliminates the need for lookup tables and root-finding,all while maintaining limited computational costs and a small memory footprint.The R-Lambert model is integrated into a buck-converter emulator equipped with a discrete PI regulator,which generates current references directly from sensed operating points,thus supporting hardware-constrained implementation.Comprehensive numerical experiments conducted on six commercial modules from various technologies(mono,poly,and multicrystalline)demonstrate significant accuracy improvements under the IEC EN 50530 near-MPP criterion:the V-Lambert solver reduces the±10%Vmpp band error by up to 61 times compared to an explicit-model baseline.Dynamic simulations under varying irradiance,temperature,and load conditions achieve millisecond-scale settling with accurate trajectory tracking.Additionally,processor-in-the-loop experimental validation on an embedded microcontroller supports the simulation results.By unifying exact analytical modeling with embedded realization,this work advances computer modeling for PV emulation,MPPT benchmarking,and controller verification in integrated renewable energy systems.
文摘In this paper a fuel cell emulator model suitable for each fuel cell type and power level is proposed. A power interface to the electronic load and a digital section are provided. The fuel cell steady-state, dynamic and thermal behaviour is modeled by the digital controller. The emulator architecture is deeply analyzed and remarks on hardware implementation algorithms are provided for further applications. The system is tested on a 10 W Proton Exchange Membrane （PEM） fuel cell and the high accuracy of the proposed emulator is shown by the comparison between experimental and simulation results.
基金supported by National Natural Science Foundation of China(No.61379016)
文摘In this paper,the transmission performances are studied in cognitive radio networks with primary user emulator and relay existence.In the proposed network,the users include primary users,secondary users and primary user emulators.The decreasing access priority of the users are primary users,primary user emulators and secondary users.Different user access to the network results in different transmission effects.We impose interference power constraints on the secondary users to protect the primary users from being interfered.We also adopt the transmission mechanism that transits among more than one secondary transmitters,secondary receivers and relays.The transition models of the transmission states are proposed to describe the transmission mechanism.To investigate the transmission performances,the theory of effective capacity is adopted.The transmission performances in terms of effective capacity are expressed and demonstrated under different transmission policies.The overall effective capacity,as the overall data traffic in the cognitive radio network,is calculated.Besides,the overall effective capacity is demonstrated under different transmission strategies.The results show the greedy transmission strategy outperforms the rest of the transmission 8 policies in the overall effective capacity.For a larger number of the users,the effective capacity converges to a certain value.
文摘The mathematical physics model of mine methane and coal dust explosion propagation was established in the research,by using continuous phase,combustion,par- ticulate equations of mathematical physics.Based upon the data from mine methane drainage roadway explosion,and mine methane and coal dust explosion propagation ex- perimental studies,the numerical emulator system of mine methane and coal dust explo- sion software was developed by using prevalent flow simulation platform,which can be used to simulate the explosion accidents process effectively.In addition,the system can also be used to determine whether coal dust involved in the explosion,and to simulate accurately the transition from deflagration to detonation in methane explosion,propagation velocity of explosion shock,attenuation pattern,and affected area of explosion.
基金supported by the National Natural Science Foundation of China(Grant Nos.51377124 and 51221005)the Foundation for the Author of National Excellent Doctoral Dissertation of China(Grant No.201337)+1 种基金the Program for New Century Excellent Talents in University of China(Grant No.NCET-13-0457)the Natural Science Basic Research Plan in Shaanxi Province of China(Grant No.2012JQ7026)
文摘As commercial memristors are still unavailable in the market, mathematic models and emulators which can imitate the features of the mernristor are meaningful for further research. In this paper, based on the analyses of characteristics of the q-φ curve, an exponential flux-controlled model, which has the quality that its memductance （memristance） will keep monotonically increasing or decreasing unless the voltage＇s polarity reverses （if not approach the boundaries）, is constructed. A new approach to designing the floating emulator of the memristor is also proposed. This floating structure can flexibly meet various demands for the current through the memristor （especially the demand for a larger current）. The simulations and experiments are presented to confirm the effectiveness of this model and its floating emulator.
文摘Power system inherently consists of capacitance and inductance in its components. Equipment with saturable inductance and circuit capacitance provides circumstances of generating ferroresonance, resulting in overvoltage and overcurrent in the connected system. The effects of ferroresonance result in insulation failure and hence damage to the equipment is unavoidable. Though many devices are proposed for mitigating such circumstances, a promising technology of using memristors may provide better performance than others in the future. A memristor emulator using the N-channel JFET J310 is used in this work. Unlike other electronic components that replicate memristor properties, the chosen memristor emulator is a passive device since it does not need any external power supply. Simulation and experimental results verify the design of a memristor emulator and the characteristics of an ideal memristor. Experimental results prove that the memristor emulator can suppress the fundamental ferroresonance induced in a prototype single phase transformer. The results of the harmonic analysis also validate the memristor performance against the conventional technique.
文摘This paper presents the modeling, simulation and practical implementation of an inverter-based diesel generator emulator. The main purpose of this emulator is for the study of frequency variations in diesel-based autonomous power systems in a laboratory environment where the operation of a real diesel generator is not possible. The emulator basically consists in a voltage source inverter with a second order output filter which voltage references are given by the model of the diesel generator. The control of the emulator is based on the digital signal processor TMS320F2812, where the mathematical models of the diesel generator and the control of the inverter are computed in real-time. Parameters for the model were obtained from commercially available components. Experimental results for different values of speed droop showed that the emulator achieves a satisfactory performance in the transient and stationary response. For the stationary response, the measured frequency deviates from theoretical values with a mean absolute error of: 0.06 Hz for 0% droop, 0.037 Hz for 3% droop, and 0.087 Hz for 5% droop. For the transient response, the measured frequency nadir deviates from simulations in: 0.05 Hz for 0% droop, 0.02 Hz for 3% droop, and 0.1 Hz for 5% droop.
文摘This paper investigates the subjective assessment of QoE of web and video services over a mobile network. To achieve this, the authors used the network emulator (NetEm) traffic control functionality to simulate the dynamic behaviour of a mobile network. Experiments were conducted in a laboratory setting and test conditions were varied to ascertain the QoE, with a focus on QoE metrics such as delay and packet loss ratio. From the experiments conducted, it was observed that there was a negative correlation between delay and average mean opinion score (MOS), and between packet loss ratio and average MOS. The results obtained can be adopted by network operators to provide better services which would lead to improved subscriber base and profitability for the operators and better QoE for the end users.
文摘This work aims at developing an automatic system for the control of the APS （air plasma spraying） plasma process in which some instability phenomena are present. APS is a versatile technique to produce coatings of powder material at high deposition rates. Using this technique, powder particles are injected into a plasma jet, where they are melted and accelerated towards a substrate. The coating microstructures and properties depend strongly on the characteristics of the plasma jet, which can be controlled by the adjustment of the process parameters. However, the imeractions among the spray variables, render optimization and control of this process are quite complex. Understanding relationships between coating properties and process parameters is mandatory to optimize the process technique and the product quality. We are interested in this work to build an on-line control model for the APS process based on the elements of artificial intelligence and to build an emulator that replicates the dynamic behavior of the process as closely as possible.
文摘Emulating massively parallel computer architectures represents a very important tool for the parallel programmers. It allows them to implement and validate their algorithms. Due to the high cost of the massively parallel real machines, they remain unavailable and not popular in the parallel computing community. The goal of this paper is to present an elaborated emulator of a 2-D massively parallel re-configurable mesh computer of size n x n processing elements (PE). Basing on the object modeling method, we develop a hard kernel of a parallel virtual machine in which we translate all the physical properties of its different components. A parallel programming language and its compiler are also devel-oped to edit, compile and run programs. The developed emulator is a multi platform system. It can be installed in any sequential computer whatever may be its operating system and its processing unit technology (CPU). The size n x n of this virtual re-configurable mesh is not limited;it depends just on the performance of the sequential machine supporting the emulator.
文摘In this paper, multimodel and neural emulators are proposed for uncoupled multivariable nonlinear plants with unknown dynamics. The contributions of this paper are to extend the emulators to multivariable non square systems and to propose a systematic method to compute the multimodel synthesis parameters. The effectiveness of the proposed emulators is shown through two simulation examples. The obtained results are very satisfactory, they illustrate the performance of both emulators and show the advantages of the multimodel emulator relatively to the neural one.
基金supported by the National Key Research and Development Program(MOST 2023YFA1606404 and MOST 2022YFA1602303)the National Natural Science Foundation of China(Nos.12347106,12147101,and 12447122)the China Postdoctoral Science Foundation(No.2024M760489).
文摘To study the uncertainty quantification of resonant states in open quantum systems,we developed a Bayesian framework by integrating a reduced basis method(RBM)emulator with the Gamow coupled-channel(GCC)approach.The RBM,constructed via eigenvector continuation and trained on both bound and resonant configurations,enables the fast and accurate emulation of resonance properties across the parameter space.To identify the physical resonant states from the emulator’s output,we introduce an overlap-based selection technique that effectively isolates true solutions from background artifacts.By applying this framework to unbound nucleus ^(6)Be,we quantified the model uncertainty in the predicted complex energies.The results demonstrate relative errors of 17.48%in the real part and 8.24%in the imaginary part,while achieving a speedup of four orders of magnitude compared with the full GCC calculations.To further investigate the asymptotic behavior of the resonant-state wavefunctions within the RBM framework,we employed a Lippmann–Schwinger(L–S)-based correction scheme.This approach not only improves the consistency between eigenvalues and wavefunctions but also enables a seamless extension from real-space training data to the complex energy plane.By bridging the gap between bound-state and continuum regimes,the L–S correction significantly enhances the emulator’s capability to accurately capture continuum structures in open quantum systems.
