The paper describes the instrumentation for studying temperature and void reactivity effects that were developed at VR-I zero power reactor. Further are described its operational parameters, fields and ways of its uti...The paper describes the instrumentation for studying temperature and void reactivity effects that were developed at VR-I zero power reactor. Further are described its operational parameters, fields and ways of its utilization as well as issues connected to its implementation into the reactor core.展开更多
Many researchers have discussed zero-inflated univariate distributions. These univariate models are not suitable, for modeling events that involve different types of counts or defects. To model several types of defect...Many researchers have discussed zero-inflated univariate distributions. These univariate models are not suitable, for modeling events that involve different types of counts or defects. To model several types of defects, multivariate Poisson model is one of the appropriate model. This can further be modified to incorporate inflation at zero and we can have multivariate zero-inflated Poisson distribution. In the present article, we introduce a new Bivariate Zero Inflated Power Series Distribution and discuss inference related to the parameters involved in the model. We also discuss the inference related to Bivariate Zero Inflated Poisson Distribution. The model has been applied to a real life data. Extension to k-variate zero inflated power series distribution is also discussed.展开更多
A multi-antenna multiple relay (MAMR) network is considered and a variation of two-hop zero-forcing amplify-forward relaying method is proposed. Deploying ZF method together with application of diagonal power allocati...A multi-antenna multiple relay (MAMR) network is considered and a variation of two-hop zero-forcing amplify-forward relaying method is proposed. Deploying ZF method together with application of diagonal power allocation matrices at the relays, it is shown that the overall MAMR network is simplified to M independent single antenna multiple relay (SAMR) networks, where M is the number of source and destination antennas. This enables to incorporate network beamforming proposed for SAMR networks. Accordingly, using the BER as the performance metric, we present simulation results to show the proposed approach outperforms the common ZF method addressed in the literature.展开更多
When the proton exchange membrane fuel cell(PEMFC)system is running,there will be a condition that does not require power output for a short time.In order to achieve zero power output under low power consumption,it is...When the proton exchange membrane fuel cell(PEMFC)system is running,there will be a condition that does not require power output for a short time.In order to achieve zero power output under low power consumption,it is necessary to consider the diversity of control targets and the complexity of dynamic models,which brings the challenge of high-precision tracking control of the stack output power and cathode intake flow.For system idle speed control,a modelbased nonlinear control framework is constructed in this paper.Firstly,the nonlinear dynamic model of output power and cathode intake flow is derived.Secondly,a control scheme combining nonlinear extended Kalman filter observer and state feedback controller is designed.Finally,the control scheme is verified on the PEMFC experimental platform and compared with the proportion-integration-differentiation(PID)controller.The experimental results show that the control strategy proposed in this paper can realize the idle speed control of the fuel cell system and achieve the purpose of zero power output.Compared with PID controller,it has faster response speed and better system dynamics.展开更多
Long-term continuous monitoring is essential for the Internet of Things(IoT),with efficient power use and sustainable energy supply as core challenges.This study presents a MEMS-based self-holding acoustic switch desi...Long-term continuous monitoring is essential for the Internet of Things(IoT),with efficient power use and sustainable energy supply as core challenges.This study presents a MEMS-based self-holding acoustic switch designed for uninterrupted monitoring of specific acoustic signals with zero power consumption.Microelectromechanical systems(MEMS)refer to miniaturized devices that integrate mechanical and electrical components on a single microchip.A mathematical model is developed to analyze the switch’s acoustic frequency response.Simulations and experiments demonstrate its acoustic-driven properties.Acoustic switches with different structural parameters are designed,achieving resonant frequencies ranging from 192 Hz to 862 Hz.Electrostatic voltages are applied to enable self-holding functionality,and the acoustic switch exhibits a contact resistance as low as 29.3 U.The acoustic switch successfully performs various functions,including acoustic sensing,frequency identification,on–off control,and self-holding,all without drawing power from an external power supply.By integrating this acoustic switch,a zero-power self-aware microsystem platform is realized,allowing zero-power sleep states without closed-loop circuits while remaining responsive to target acoustic signals.This technology effectively supports long-term,large-scale deployment of unattended IoT terminals.展开更多
在微源半桥变流器串联结构星型连接微电网(half-bridge converter series Y-connection microgrid,HCSY-MG)系统中,由于环境因素(如风速、光照等)影响,各风、光微源的输出功率存在显著差异,导致系统三相输出功率不一致,进而引发三相并...在微源半桥变流器串联结构星型连接微电网(half-bridge converter series Y-connection microgrid,HCSY-MG)系统中,由于环境因素(如风速、光照等)影响,各风、光微源的输出功率存在显著差异,导致系统三相输出功率不一致,进而引发三相并网电流不对称,严重影响系统的并网运行。为解决该问题,提出了一种正序分量合成零序电压注入和过调制补偿相结合的控制方法。该方法利用与三相电网电压同相位的正序分量合成零序电压,与传统方法相比,简化了计算过程。然而,零序电压注入的功率平衡能力有限,当三相功率不平衡程度较大时,系统容易发生过调制。为此,过调制补偿通过修改零序电压,进一步扩大了系统的相间功率平衡范围,从而确保在相间功率不平衡的情况下,系统仍然能够正常运行,且并网电流能够满足并网要求。最后,通过仿真和实验验证了所提控制策略的正确性与可行性。展开更多
目的电力设备巡检影像缺陷检测对于提高电力传输的安全性和电网运行的可靠性具有重要作用。但由于相应训练数据集的构造成本高昂,传统的监督学习方法难以适应电力设备巡检影像缺陷检测。同时电力设备巡检影像中通常含有复杂多样的背景,...目的电力设备巡检影像缺陷检测对于提高电力传输的安全性和电网运行的可靠性具有重要作用。但由于相应训练数据集的构造成本高昂,传统的监督学习方法难以适应电力设备巡检影像缺陷检测。同时电力设备巡检影像中通常含有复杂多样的背景,严重干扰了模型对缺陷的检测。方法基于视觉语言模型并结合文本提示,提出了电力设备巡检影像零样本缺陷检测模型。模型中含有多个双专家模块,在由视觉语言模型获得文本特征和视觉特征后,经多个双专家模块处理并融合,得到像素级的缺陷检测结果。同时,构建了具有像素级掩码标注的电力设备巡检影像数据集对模型性能进行全面评测。结果在本文构建的电力设备巡检影像测试数据集上与SAA+(segment any anomaly+)、AnomalyGPT、WinCLIP(window-based CLIP)、PaDiM(patch distribution modeling)和PatchCore进行比较,在像素级的缺陷分割性能表现上,AUROC(area under the receiver operating characteristic curve)平均提升18.1%,F1-max(F1 score at optimal threshold)平均提升26.1%;在图像级的缺陷分类性能表现上,AUROC平均提升20.2%,AP(average precision)平均提升10.0%。具体到数据集中的各个电力设备,模型在像素级缺陷分割性能表现上,均获得最好结果。同时进行了消融实验,证明了双专家模块对提升模型缺陷检测精度的显著效果。结论本文模型以零样本的方式,避免了构造电力设备巡检影像数据集的高昂成本。同时提出的双专家模块,使模型减少了受巡检影像复杂背景区域的干扰。展开更多
文摘The paper describes the instrumentation for studying temperature and void reactivity effects that were developed at VR-I zero power reactor. Further are described its operational parameters, fields and ways of its utilization as well as issues connected to its implementation into the reactor core.
文摘Many researchers have discussed zero-inflated univariate distributions. These univariate models are not suitable, for modeling events that involve different types of counts or defects. To model several types of defects, multivariate Poisson model is one of the appropriate model. This can further be modified to incorporate inflation at zero and we can have multivariate zero-inflated Poisson distribution. In the present article, we introduce a new Bivariate Zero Inflated Power Series Distribution and discuss inference related to the parameters involved in the model. We also discuss the inference related to Bivariate Zero Inflated Poisson Distribution. The model has been applied to a real life data. Extension to k-variate zero inflated power series distribution is also discussed.
文摘A multi-antenna multiple relay (MAMR) network is considered and a variation of two-hop zero-forcing amplify-forward relaying method is proposed. Deploying ZF method together with application of diagonal power allocation matrices at the relays, it is shown that the overall MAMR network is simplified to M independent single antenna multiple relay (SAMR) networks, where M is the number of source and destination antennas. This enables to incorporate network beamforming proposed for SAMR networks. Accordingly, using the BER as the performance metric, we present simulation results to show the proposed approach outperforms the common ZF method addressed in the literature.
基金Supported by the Major Science and Technology Projects in Jilin Province and Changchun City(20220301010GX).
文摘When the proton exchange membrane fuel cell(PEMFC)system is running,there will be a condition that does not require power output for a short time.In order to achieve zero power output under low power consumption,it is necessary to consider the diversity of control targets and the complexity of dynamic models,which brings the challenge of high-precision tracking control of the stack output power and cathode intake flow.For system idle speed control,a modelbased nonlinear control framework is constructed in this paper.Firstly,the nonlinear dynamic model of output power and cathode intake flow is derived.Secondly,a control scheme combining nonlinear extended Kalman filter observer and state feedback controller is designed.Finally,the control scheme is verified on the PEMFC experimental platform and compared with the proportion-integration-differentiation(PID)controller.The experimental results show that the control strategy proposed in this paper can realize the idle speed control of the fuel cell system and achieve the purpose of zero power output.Compared with PID controller,it has faster response speed and better system dynamics.
基金supported in part by the National Key Research and Development Program(Grant No.2023YFB3211200)the National Nature Science Foundation of China(Grant No.U21A6003 and L2324213).
文摘Long-term continuous monitoring is essential for the Internet of Things(IoT),with efficient power use and sustainable energy supply as core challenges.This study presents a MEMS-based self-holding acoustic switch designed for uninterrupted monitoring of specific acoustic signals with zero power consumption.Microelectromechanical systems(MEMS)refer to miniaturized devices that integrate mechanical and electrical components on a single microchip.A mathematical model is developed to analyze the switch’s acoustic frequency response.Simulations and experiments demonstrate its acoustic-driven properties.Acoustic switches with different structural parameters are designed,achieving resonant frequencies ranging from 192 Hz to 862 Hz.Electrostatic voltages are applied to enable self-holding functionality,and the acoustic switch exhibits a contact resistance as low as 29.3 U.The acoustic switch successfully performs various functions,including acoustic sensing,frequency identification,on–off control,and self-holding,all without drawing power from an external power supply.By integrating this acoustic switch,a zero-power self-aware microsystem platform is realized,allowing zero-power sleep states without closed-loop circuits while remaining responsive to target acoustic signals.This technology effectively supports long-term,large-scale deployment of unattended IoT terminals.
文摘在微源半桥变流器串联结构星型连接微电网(half-bridge converter series Y-connection microgrid,HCSY-MG)系统中,由于环境因素(如风速、光照等)影响,各风、光微源的输出功率存在显著差异,导致系统三相输出功率不一致,进而引发三相并网电流不对称,严重影响系统的并网运行。为解决该问题,提出了一种正序分量合成零序电压注入和过调制补偿相结合的控制方法。该方法利用与三相电网电压同相位的正序分量合成零序电压,与传统方法相比,简化了计算过程。然而,零序电压注入的功率平衡能力有限,当三相功率不平衡程度较大时,系统容易发生过调制。为此,过调制补偿通过修改零序电压,进一步扩大了系统的相间功率平衡范围,从而确保在相间功率不平衡的情况下,系统仍然能够正常运行,且并网电流能够满足并网要求。最后,通过仿真和实验验证了所提控制策略的正确性与可行性。
文摘目的电力设备巡检影像缺陷检测对于提高电力传输的安全性和电网运行的可靠性具有重要作用。但由于相应训练数据集的构造成本高昂,传统的监督学习方法难以适应电力设备巡检影像缺陷检测。同时电力设备巡检影像中通常含有复杂多样的背景,严重干扰了模型对缺陷的检测。方法基于视觉语言模型并结合文本提示,提出了电力设备巡检影像零样本缺陷检测模型。模型中含有多个双专家模块,在由视觉语言模型获得文本特征和视觉特征后,经多个双专家模块处理并融合,得到像素级的缺陷检测结果。同时,构建了具有像素级掩码标注的电力设备巡检影像数据集对模型性能进行全面评测。结果在本文构建的电力设备巡检影像测试数据集上与SAA+(segment any anomaly+)、AnomalyGPT、WinCLIP(window-based CLIP)、PaDiM(patch distribution modeling)和PatchCore进行比较,在像素级的缺陷分割性能表现上,AUROC(area under the receiver operating characteristic curve)平均提升18.1%,F1-max(F1 score at optimal threshold)平均提升26.1%;在图像级的缺陷分类性能表现上,AUROC平均提升20.2%,AP(average precision)平均提升10.0%。具体到数据集中的各个电力设备,模型在像素级缺陷分割性能表现上,均获得最好结果。同时进行了消融实验,证明了双专家模块对提升模型缺陷检测精度的显著效果。结论本文模型以零样本的方式,避免了构造电力设备巡检影像数据集的高昂成本。同时提出的双专家模块,使模型减少了受巡检影像复杂背景区域的干扰。
