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An Adaptive Data-driven Method Based on Fuzzy Logic for Determining Power System Voltage Status

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Journal of Modern Power Systems and Clean Energy 2024年第3期12卷 707-718页

作者： Sirwan Shazdeh Hêmin Golpîra Hassan Bevrani the SMGRC University of KurdistanSanandajIran Power Systems Modeling&Simulation lab Department of Electrical EngineeringUniversity of KurdistanKurdistanSanandaj 66177-15175Iran

This paper proposes an adaptive method based on fuzzy logic that utilizes data from phasor measurement units(PMUs) to assess and classify generating-side voltage trajectories. The voltage variable and its associated derivatives are used as the input variables of a fuzzy-logic block. In addition, the voltage trajectory is compared with the pre-selected pilot-bus voltage to make a reliable decision about the voltage operational state. Different types of short-term voltage dynamics are considered in the proposed method. The fuzzy membership functions are determined using a systematic method that considers the current situation of the voltage trajectory. Finally, the voltage status is categorized into four classes to determine appropriate remedial actions. The proposed method is validated on a IEEE 73-bus power system in a MATlaB environment.

关键词： Fuzzy logic fault-induced delayed voltage recovery phasor measurement unit(PMU) short-term voltage stability situational awareness voltage classification

Biderivations of Hom-Lie Algebras and Superalgebras

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Acta Mathematica Sinica,English Series 2024年第10期40卷 2337-2358页

作者： la Mei YUAN Jia Xin LI School of Mathematics Harbin Institute of Technology

On Hom-Lie algebras and superalgebras, we introduce the notions of biderivations and linear commuting maps, and compute them for some typical Hom-Lie algebras and superalgebras,including the q-deformed W(2, 2) algebra... 详细信息

关键词： 17A30 17A60 17B05 17B60 17B70 biderivations Hom-Lie algebras linear commuting maps q-deformed W(2 2) algebra q-deformed Witt algebra q-deformed Witt superalgebra

Truly optimal semi-active damping to control free vibration of a single degree of freedom system

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Theoretical & Applied Mechanics Letters 2024年第2期14卷 142-145页

作者： Viet Duc la Ngoc Tuan Nguyen Institute of Mechanics Vietnam Academy of Science and TechnologyHanoi 10000Vietnam Graduate University of Science and Technology Vietnam Academy of Science and TechnologyHanoi 10000Vietnam

This paper studies a single degree of freedom system under free vibration and controlled by a general semiactive damping.A general integral of squared error is considered as the performance index.A one-time switching damping controller is proposed and *** pontryagin maximum principle is used to prove that no other form of semi-active damping can provide the better performance than the proposed one-time switching damping.

关键词： Analytical optimization Quadratic integral Lyapunov equation Pontryagin maximum principle

A convolutional neural network to detect possible hidden data in spatial domain images

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Cybersecurity 2024年第1期7卷 37-52页

作者： Jean De la Croix Ntivuguruzwa Tohari Ahmad Department of Informatics Institut Teknologi Sepuluh Nopember(ITS)Kampus ITS Keputih SukoliloSurabaya60111Indonesia African Center of Excellence in the Internet of Things College of Science and TechnologyUniversity of Rwanda3900KigaliRwanda

Hiding secret data in digital multimedia has been essential to protect the ***,attackers with a steganalysis technique may break *** steganalysis methods have good results with conventional Machine Learning(ML)techniques;however,the introduction of convolutional Neural Network(CNN),a deep learning paradigm,achieved better performance over the previously proposed ML-based *** the existing CNN-based approaches yield good results,they present performance issues in classification accuracy and stability in the network training *** research proposes a new method with a CNN architecture to improve the hidden data detection accuracy and the training phase stability in spatial domain *** proposed method comprises three phases:pre-processing,feature extraction,and ***,in the pre-processing phase,we use spatial rich model filters to enhance the noise within images altered by data hiding;secondly,in the feature extraction phase,we use two-dimensional depthwise separable convolutions to improve the signal-to-noise and regular convolutions to model local features;and finally,in the classification,we use multi-scale average pooling for local features aggregation and representability enhancement regardless of the input size variation,followed by three fully connected layers to form the final feature maps that we transform into class probabilities using the softmax *** results identify an improvement in the accuracy of the considered recent scheme ranging between 4.6 and 10.2%with reduced training time up to 30.81%.

关键词： Information security Spatial domain steganalysis Deep learning convolutional neural network Infrastructure

ZnSb/Ti_(3)C_(2)T_(x)MXene van der Waals heterojunction for flexible near-infrared photodetector arrays

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Journal of Semiconductors 2024年第5期45卷 99-105页

作者： Chuqiao Hu Ruiqing Chai Zhongming Wei la Li Guozhen Shen State Key laboratory for Superlattices and Microstructures Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China Center of Materials Science and Optoelectronic Engineering University of Chinese Academy of SciencesBeijing 100049China School of Integrated Circuits and Electronics Beijing Institute of TechnologyBeijing 100081China

Two-dimension(2D)van der Waals heterojunction holds essential promise in achieving high-performance flexible near-infrared(NIR)***,we report the successful fabrication of ZnSb/Ti_(3)C_(2)T_(x)MXene based flexible NIR photodetector array via a facile photolithography *** single ZnSb/Ti_(3)C_(2)T_(x)photodetector exhibited a high light-to-dark current ratio of 4.98,fast response/recovery time(2.5/1.3 s)and excellent stability due to the tight connection between 2D ZnSb nanoplates and 2D Ti_(3)C_(2)T_(x)MXene nanoflakes,and the formed 2D van der Waals *** polyethylene terephthalate(PET)substrate enables the ZnSb/Ti_(3)C_(2)T_(x)photodetector withstand bending such that stable photoelectrical properties with non-obvious change were maintained over 5000 bending ***,the ZnSb/Ti_(3)C_(2)T_(x)photodetectors were integrated into a 26×5 device array,realizing a NIR image sensing application.

关键词： ZnSb nanoplates Ti_(3)C_(2)T_(x)MXene van der Waals heterojunction flexible photodetector image sensing

particle Size Optimization of Thermochemical Salt Hydrates for High Energy Density Thermal Storage

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Energy & Environmental Materials 2024年第2期7卷 326-333页

作者： Andrew Martin Drew Lilley raνi Prasher Sumanjeet Kaur Energy Technologies Area Lawrence Berkeley National LaboratoryBerkeleyCA 94720USA Department of Mechanical Engineering UC BerkeleyBerkeleyCA 94720USA

Thermal energy storage(TES)solutions offer opportunities to reduce energy consumption,greenhouse gas emissions,and ***,they can help reduce the peak load and address the intermittency of renewable energy sources by time shifting the load,which are critical toward zero energy *** materials(TCMs)as a class of TES undergo a solid-gas reversible chemical reaction with water vapor to store and release energy with high storage capacities(600 kWh m^(-3))and negligible self-discharge that makes them uniquely suited as compact,stand-alone units for daily or seasonal ***,TCMs suffer from instabilities at the material(salt particles)and reactor level(packed beds of salt),resulting in poor multi-cycle efficiency and high-levelized cost of *** this study,a model is developed to predict the pulverization limit or Rcrit of various salt hydrates during thermal *** is critical as it provides design rules to make mechanically stable TCM composites as well as enables the use of more energy-efficient manufacturing process(solid-state mixing)to make the *** model is experimentally validated on multiple TCM salt hydrates with different water content,and effect of Rcrit on hydration and dehydration kinetics is also investigated.

关键词： high energy density hydration kinetics long-term cycling thermal energy storage thermochemical materials

High Seebeck coefficient Thermally Chargeable Supercapacitor with Synergistic Effect of Multichannel Ionogel Electrolyte and Ti_(3)C_(2)T_(x)MXene-Based composite Electrode

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Energy & Environmental Materials 2024年第6期7卷 367-377页

作者： Zhongming Chen Zhijian Du la Li Kai Jiang Di Chen Guozhen Shen School of Mathematics and Physics University of Science and Technology BeijingBeijing 100083China School of Integrated Circuits and Electronics Beijing Institute of TechnologyBeijing 100081China Faculty of Hepato-pancreato-Biliary Surgery Chinese PLA General HospitalInstitute of Hepatobiliary Surgery of Chinese PLA&Key Laboratory of Digital Hepetobiliary SurgeryChinese PLABeijing 100853China

Thermally chargeable supercapacitors can collect low-grade heat generated by the human body and convert it into electricity as a power supply unit for wearable ***,the low Seebeck coefficient and heat-to-electricity conversion efficiency hinder further *** this paper,we designed a high-performance thermally chargeable supercapacitor device composed of ZnMn_(2)O_(4)@Ti_(3)C_(2)T_(x)MXene composites(ZMO@Ti_(3)C_(2)T_(x)MXene)electrode and UIO-66 metal–organic framework doped multichannel polyvinylidene fluoridehexafluoro-propylene ionogel electrolyte,which realized the thermoelectric conversion and electrical energy storage at the same *** thermally chargeable supercapacitor device exhibited a high Seebeck coefficient of 55.4 mV K^(−1),thermal voltage of 243 mV,and outstanding heat-to-electricity conversion efficiency of up to 6.48%at the temperature difference of 4.4 *** addition,this device showed excellent charge–discharge cycling stability at high-temperature differences(3 K)and low-temperature differences(1 K),*** two thermally chargeable supercapacitor units in series,the generated output voltage of 500 mV further confirmed the stability of *** a single device was worn on the arm,a thermal voltage of 208.3 mV was obtained indicating the possibility of application in wearable electronics.

关键词： ionogel electrode Soret effect thermally chargeable supercapacitor Ti_(3)C_(2)T_(x)MXene UIO-66 MOF

The Influence of Significant Public Health Events on Offline consumption and Its pathways

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Journal of Systems Science and Systems Engineering 2024年第5期33卷 627-648页

作者： Baile Lu Kewei Zhou Shuai Hao la Ta Hongyan Dai Weihua Zhou college of Systems Engineering National University of Defense TechnologyChangsha 410073China Business School Central University of Finance and EconomicsBeijing 100081China Department of Marketing and Operations Management College of BusinessSouthern University of Science and TechnologyShenzhen 518055China School of Management Zhejiang UniversityHangzhou 310058China

In the face of a significant public health event,consumers may either increase their panic buying or decrease their willingness to make *** study focuses on the impact of a significant public health event on offline store sales and consumer consumption,utilizing data from chain convenience stores in Hefei and Wuhu during early 2019 and early 2020 in *** a difference-in-differences model,the study investigates the effect of the significant public health event outbreak on weekly store sales,order numbers,and consumer consumption in terms of product quantities,transaction amount,average amount per order,and transaction *** from prior literature that finds hoarding behavior of consumers online,the findings of this paper indicate a significant reduction in stores’offline weekly sales and order numbers,as well as consumers’offline weekly consumption across the four dimensions,as a result of the significant public health event ***,employing a mediation model,the study explores the pathway of population mobility through which the significant public health event adversely affects offline ***,subset analysis is conducted for stores located in different areas and consumers with varying characteristics,revealing that the aforementioned conclusions predominantly apply to stores situated in office areas and residential areas,as well as consumers with either no apparent preference for different product categories or a noticeable preference for food.

关键词： Significant public health event offline consumption population mobility mediating effect

An exploration of meteorological effects on PM2.5 air quality in several provinces and cities in Vietnam

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Journal of Environmental Sciences 2024年第11期145卷 139-151页

作者： Giang Tran Huong Nguyen Luan Thien la Huy Hoang-cong Anh Hoang Le Faculty of Chemistry and Environment Dalat UniversityLam Dong ProvinceVietnam Environmental Protection Agency Lam Dong Province Department of Natural Resources and EnvironmentLam Dong ProvinceVietnam Northern Center for Environmental Monitoring Environmental Pollution Control DepartmentHa Noi CityVietnam Faculty of Environment University of ScienceHo Chi Minh CityVietnam Vietnam National University Ho Chi Minh CityVietnam

Linking meteorology and air pollutants is a key *** study investigated meteorological effects on PM_(2.5)concentration using the advanced convergent cross mapping method,utilizing hourly PM_(2.5)concentration and six meteorological factors across eight provinces and cities in *** demonstrated that temperature(ρ=0.30)and radiation(ρ=0.30)produced the highest effects,followed by humidity(ρ=0.28)and wind speed(ρ=0.24),while pressure(ρ=0.22)and wind direction(ρ=0.17)produced the weakest effects on PM_(2.5)*** theρvalues showed that temperature,wind speed,and wind direction had greater impacts on PM_(2.5)concentration during the dry season whereas radiation had a more influence during the wet season;Southern stations experienced larger meteorological ***,humidity,pressure,and wind direction had both positive and negative influences on PM_(2.5)concentration,while radiation and wind speed mostly had negative *** PM_(2.5)pollution episodes,there wasmore contribution ofmeteorological effects on PM_(2.5)concentration indicated byρ*** contaminated levels,humidity(ρ=0.45)was the most dominant factor affecting PM_(2.5)concentration,followed by temperature(ρ=0.41)and radiation(ρ=0.40).Pollution episodes were pointed out to be more prevalent under higher humidity,higher pressure,lower temperature,lower radiation,and lower wind ***ρcalculation also revealed that lower temperature,lower radiation,and higher humidity greatly accelerated each other under pollution episodes,further enhancing PM_(2.5)*** findings contributed to the literature on meteorology and air pollution interaction.

关键词： Fine particulate matter Air pollution Meteorological effect convergent cross mapping Causality analysis Vietnam