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Hybrid data-driven framework for shale gas production performance analysis via game theory, machine learning, and optimization approaches 被引量:1
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作者 Jin Meng Yu-Jie Zhou +4 位作者 Tian-Rui Ye Yi-Tian Xiao Ya-Qiu Lu Ai-Wei Zheng Bang Liang 《Petroleum Science》 SCIE EI CAS CSCD 2023年第1期277-294,共18页
A comprehensive and precise analysis of shale gas production performance is crucial for evaluating resource potential,designing a field development plan,and making investment decisions.However,quantitative analysis ca... A comprehensive and precise analysis of shale gas production performance is crucial for evaluating resource potential,designing a field development plan,and making investment decisions.However,quantitative analysis can be challenging because production performance is dominated by the complex interaction among a series of geological and engineering factors.In fact,each factor can be viewed as a player who makes cooperative contributions to the production payoff within the constraints of physical laws and models.Inspired by the idea,we propose a hybrid data-driven analysis framework in this study,where the contributions of dominant factors are quantitatively evaluated,the productions are precisely forecasted,and the development optimization suggestions are comprehensively generated.More specifically,game theory and machine learning models are coupled to determine the dominating geological and engineering factors.The Shapley value with definite physical meaning is employed to quantitatively measure the effects of individual factors.A multi-model-fused stacked model is trained for production forecast,which provides the basis for derivative-free optimization algorithms to optimize the development plan.The complete workflow is validated with actual production data collected from the Fuling shale gas field,Sichuan Basin,China.The validation results show that the proposed procedure can draw rigorous conclusions with quantified evidence and thereby provide specific and reliable suggestions for development plan optimization.Comparing with traditional and experience-based approaches,the hybrid data-driven procedure is advanced in terms of both efficiency and accuracy. 展开更多
关键词 Shale gas Production performance DATA-DRIVEN Dominant factors Game theory Machine learning Derivative-free optimization
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Quantum dynamical resource theory under resource non-increasing framework
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作者 杨思忍 于长水 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第4期184-192,共9页
We define the resource non-increasing(RNI)framework to study the dynamical resource theory.With this definition,we propose several potential quantification candidates under various free operation sets.For explicit dem... We define the resource non-increasing(RNI)framework to study the dynamical resource theory.With this definition,we propose several potential quantification candidates under various free operation sets.For explicit demonstrations,we quantify the quantum dynamical coherence in the scenarios with and without post-selective measurements.Correspondingly,we show that the maximally incoherent operations(MIO)and the incoherent operations(IO)in the static coherence resource theory are free in the sense of dynamical coherence.We also provide operational meanings for the measures by the quantum discrimination tasks.Moreover,for the dynamical total coherence,we also present convenient measures and give the analytic calculation for the amplitude damping channel. 展开更多
关键词 quantum resource theory quantum channels quantum coherence
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A label noise filtering and label missing supplement framework based on game theory
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作者 Yuwen Liu Rongju Yao +4 位作者 Song Jia Fan Wang Ruili Wang Rui Ma Lianyong Qi 《Digital Communications and Networks》 SCIE CSCD 2023年第4期887-895,共9页
Labeled data is widely used in various classification tasks.However,there is a huge challenge that labels are often added artificially.Wrong labels added by malicious users will affect the training effect of the model... Labeled data is widely used in various classification tasks.However,there is a huge challenge that labels are often added artificially.Wrong labels added by malicious users will affect the training effect of the model.The unreliability of labeled data has hindered the research.In order to solve the above problems,we propose a framework of Label Noise Filtering and Missing Label Supplement(LNFS).And we take location labels in Location-Based Social Networks(LBSN)as an example to implement our framework.For the problem of label noise filtering,we first use FastText to transform the restaurant's labels into vectors,and then based on the assumption that the label most similar to all other labels in the location is most representative.We use cosine similarity to judge and select the most representative label.For the problem of label missing,we use simple common word similarity to judge the similarity of users'comments,and then use the label of the similar restaurant to supplement the missing labels.To optimize the performance of the model,we introduce game theory into our model to simulate the game between the malicious users and the model to improve the reliability of the model.Finally,a case study is given to illustrate the effectiveness and reliability of LNFS. 展开更多
关键词 Label noise FastText Cosine similarity Game theory LSTM
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The English Subtitle Translation of Quanzhou’s World Heritage Application Documentary: A Frame Theory Perspective
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作者 LAI Liting CHEN Min 《Sino-US English Teaching》 2023年第8期334-339,共6页
Based on Fillmore’s frame theory, this paper examines the translator’s cognitive frame operation in the English subtitle translation of Quanzhou’s World Heritage application documentary. It analyzes and discusses h... Based on Fillmore’s frame theory, this paper examines the translator’s cognitive frame operation in the English subtitle translation of Quanzhou’s World Heritage application documentary. It analyzes and discusses how the translator maximizes translation effect between the source language and the target language, so as to enhance the readability of documentary subtitles and promote the spread of traditional Chinese culture. The findings are as follows: Firstly, in the translation process, the frame operations used by the translator include frame correspondence, intra-frame operations, frame replacement, frame perspective shift and frame transplantation. Secondly, cultural documentaries are full of culture-loaded words, for which the translator usually uses frame transplantation. Thirdly, due to the instantaneous nature of subtitles, intra-frame operations and frame replacement are applied in terms of cultural background of the target language audience. Besides, in order to enhance the audience’s reading experience, there may be some changes of narrative perspective in the English translation of cultural documentaries. 展开更多
关键词 frame semantics frame operation Quanzhou’s World Heritage application documentary subtitle translation
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A renewal theory based performance and configuration framework of the IEEE 802.11ah RAW mechanism
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作者 Hamid Taramit Luis Orozco-Barbosa Abdelkrim Haqiq 《Digital Communications and Networks》 SCIE CSCD 2023年第1期236-251,共16页
IEEE 802.11ah is a new Wi-Fi standard for sub-1Ghz communications,aiming to address the challenges of the Internet of Things(IoT).Significant changes in the legacy 802.11 standards have been proposed to improve the ne... IEEE 802.11ah is a new Wi-Fi standard for sub-1Ghz communications,aiming to address the challenges of the Internet of Things(IoT).Significant changes in the legacy 802.11 standards have been proposed to improve the network performance in high contention scenarios,the most important of which is the Restricted Access Window(RAW)mechanism.This mechanism promises to increase the throughput and energy efficiency by dividing stations into different groups.Under this scheme,only the stations belonging to the same group may access the channel,which reduces the collision probability in dense scenarios.However,the standard does not define the RAW grouping strategy.In this paper,we develop a new mathematical model based on the renewal theory,which allows for tracking the number of transmissions within the limited RAW slot contention period defined by the standard.We then analyze and evaluate the performance of RAW mechanism.We also introduce a grouping scheme to organize the stations and channel access time into different groups within the RAW.Furthermore,we propose an algorithm to derive the RAW configuration parameters of a throughput maximizing grouping scheme.We additionally explore the impact of channel errors on the contention within the time-limited RAW slot and the overall RAW optimal configuration.The presented analytical framework can be applied to many other Wi-Fi standards that integrate periodic channel reservations.Extensive simulations using the MATLAB software validate the analytical model and prove the effectiveness of the proposed RAW configuration scheme. 展开更多
关键词 IEEE 802.11ah Performance evaluation Renewal theory RAW mechanism Internet of things
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Optimal Portfolio Selection with Delay under the Framework of Uncertainty Theory
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作者 Jun Long Sanyun Zeng 《Journal of Applied Mathematics and Physics》 2023年第10期2848-2870,共23页
This study focuses on investigating the optimal investment strategy for an optimization problem with delay using the uncertainty theory. The financial market is composed of a risk-free asset and a risk asset with an u... This study focuses on investigating the optimal investment strategy for an optimization problem with delay using the uncertainty theory. The financial market is composed of a risk-free asset and a risk asset with an uncertain price process described by an uncertain differential equation. An optimization problem is assumed that its objective is a nonlinear function of decision variable. By deriving the equation of optimality, an analytical solution is obtained for the optimal delay investment strategy, and the optimal delay value function. Finally, an economic analysis and numerical sensitivity analysis are conducted to evaluate the research results. 展开更多
关键词 DELAY Uncertainty theory Equation of Optimality Optimal Value Function Optimal Investment Strategy
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Dynamic interactive bitwise meta-holography with ultra-high computational and display frame rates
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作者 Yuncheng Liu Ke Xu +4 位作者 Xuhao Fan Xinger Wang Xuan Yu Wei Xiong Hui Gao 《Opto-Electronic Advances》 SCIE EI CAS CSCD 2024年第1期36-46,共11页
Interactive holography offers unmatched levels of immersion and user engagement in the field of future display.Despite of the substantial progress has been made in dynamic meta-holography,the realization of real-time,... Interactive holography offers unmatched levels of immersion and user engagement in the field of future display.Despite of the substantial progress has been made in dynamic meta-holography,the realization of real-time,highly smooth interactive holography remains a significant challenge due to the computational and display frame rate limitations.In this study,we introduced a dynamic interactive bitwise meta-holography with ultra-high computational and display frame rates.To our knowledge,this is the first reported practical dynamic interactive metasurface holographic system.We spa-tially divided the metasurface device into multiple distinct channels,each projecting a reconstructed sub-pattern.The switching states of these channels were mapped to bitwise operations on a set of bit values,which avoids complex holo-gram computations,enabling an ultra-high computational frame rate.Our approach achieves a computational frame rate of 800 kHz and a display frame rate of 23 kHz on a low-power Raspberry Pi computational platform.According to this methodology,we demonstrated an interactive dynamic holographic Tetris game system that allows interactive gameplay,color display,and on-the-fly hologram creation.Our technology presents an inspiration for advanced dynamic meta-holography,which is promising for a broad range of applications including advanced human-computer interaction,real-time 3D visualization,and next-generation virtual and augmented reality systems. 展开更多
关键词 interactive display meta-holography bitwise operation ultra-high frame rate
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Experimental and numerical study regarding H-steel all-bolted connection steel frame with composite wall boards
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作者 Fan Min Guo Hongchao +2 位作者 Li Shen Wang Zhenshan Wang Huaqiang 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2024年第2期427-443,共17页
H-steel all-bolted connection steel frame structures with heat preservation and decoration composite wall boards were investigated and the seismic performances of three scaled specimens were studied.The failure modes,... H-steel all-bolted connection steel frame structures with heat preservation and decoration composite wall boards were investigated and the seismic performances of three scaled specimens were studied.The failure modes,hysteresis curves,bearing capacity,ductility,energy dissipation capacity,stiffness degradation and strain distribution were discussed.The calculation method of structural theoretical internal force was presented.The results showed that the overall structural seismic performance was better,and the structural ductility met the demands of elastic-plastic inter-story drift angle for seismic design.The H-steel weak-axis connection structure obtained better energy dissipation capacity,and its bearing capacity and stiffness were slightly different from the strong-axis connection.The heat preservation and decoration performance of composite wallboard and the all-bolted connection of the steel frame realized prefabrication during the whole construction period.The plastic hinge of the steel beam can be moved outwards because of the L-angles,which effectively avoids stress concentration in joint areas and expands the plastic hinge range.The errors between the theoretical structural capacity calculated by the plastic analysis method and the test results were within 2.44%.In addition,structural failure mechanisms and bearing capacities were verified by the finite element(FE)analysis,and the effects of the main parameters on the structures were investigated.The FE verification results were the same as in the test.The research results provide theoretical support and technical guidance for the application of thermal insulation and decorative composite wall panels in H-shaped steel all-bolted steel frames. 展开更多
关键词 composite wall boards all-bolted steel frame H-steel low-cyclic loading failure modes
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Combining stochastic density functional theory with deep potential molecular dynamics to study warm dense matter
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作者 Tao Chen Qianrui Liu +2 位作者 Yu Liu Liang Sun Mohan Chen 《Matter and Radiation at Extremes》 SCIE EI CSCD 2024年第1期44-57,共14页
In traditional finite-temperature Kohn–Sham density functional theory(KSDFT),the partial occupation of a large number of high-energy KS eigenstates restricts the use of first-principles molecular dynamics methods at ... In traditional finite-temperature Kohn–Sham density functional theory(KSDFT),the partial occupation of a large number of high-energy KS eigenstates restricts the use of first-principles molecular dynamics methods at extremely high temperatures.However,stochastic density functional theory(SDFT)can overcome this limitation.Recently,SDFT and the related mixed stochastic–deterministic density functional theory,based on a plane-wave basis set,have been implemented in the first-principles electronic structure software ABACUS[Q.Liu and M.Chen,Phys.Rev.B 106,125132(2022)].In this study,we combine SDFT with the Born–Oppenheimer molecular dynamics method to investigate systems with temperatures ranging from a few tens of eV to 1000 eV.Importantly,we train machine-learning-based interatomic models using the SDFT data and employ these deep potential models to simulate large-scale systems with long trajectories.Subsequently,we compute and analyze the structural properties,dynamic properties,and transport coefficients of warm dense matter. 展开更多
关键词 STOCHASTIC theory FUNCTIONAL
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Resilience-incorporated seismic risk assessment of precast concrete frames with“dry”connections
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作者 Wu Chenhao Tang Yuchuan +1 位作者 Cao Xuyang Wu Gang 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2024年第2期403-425,共23页
A resilience-incorporated risk assessment framework is proposed and demonstrated in this study to manifest the advantageous seismic resilience of precast concrete frame(PCF)structures with“dry”connections in terms o... A resilience-incorporated risk assessment framework is proposed and demonstrated in this study to manifest the advantageous seismic resilience of precast concrete frame(PCF)structures with“dry”connections in terms of their low damage and rapid recovery.The framework integrates various uncertainties in the seismic hazard,fragility,capacity,demand,loss functions,and post-earthquake recovery.In this study,the PCF structures are distinguished from ordinary reinforced concrete frame(RCF)structures by characterizing multiple limit states for the PCF based on its unique damage mechanisms.Accordingly,probabilistic story-wise pushover analyses are performed to yield story-wise capacities for the predefined limit states.In the seismic resilience analysis,a step-wise recovery model is proposed to idealize the functionality recovery process,with separate considerations of the repair and non-repair events.The recovery model leverages the economic loss and downtime to delineate the stochastic post-earthquake recovery curves for the resilience loss estimation.As such,contingencies in the probabilistic post-earthquake repairs are incorporated and the empirical judgments on the recovery parameters are largely circumvented.The proposed framework is demonstrated through a comparative study between two“dry”connected PCFs and one RCF designed as alternative structural systems for a prototype building.The results from the risk quantification indicate that the PCFs show reduced loss hazards and lower expected losses relative to the RCF.Particularly,the PCF equipped with energy dissipation devices at the“dry”connections largely reduces the expected economic loss,downtime,and resilience loss by 29%,56%,and 60%,respectively,compared to the RCF. 展开更多
关键词 precast concrete frame non-emulative precast system seismic resilience seismic risk functional recovery
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Local thermal conductivity of inhomogeneous nano-fluidic films:A density functional theory perspective
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作者 孙宗利 康艳霜 康艳梅 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第4期594-603,共10页
Combining the mean field Pozhar-Gubbins(PG)theory and the weighted density approximation,a novel method for local thermal conductivity of inhomogeneous fluids is proposed.The correlation effect that is beyond the mean... Combining the mean field Pozhar-Gubbins(PG)theory and the weighted density approximation,a novel method for local thermal conductivity of inhomogeneous fluids is proposed.The correlation effect that is beyond the mean field treatment is taken into account by the simulation-based empirical correlations.The application of this method to confined argon in slit pore shows that its prediction agrees well with the simulation results,and that it performs better than the original PG theory as well as the local averaged density model(LADM).In its further application to the nano-fluidic films,the influences of fluid parameters and pore parameters on the thermal conductivity are calculated and investigated.It is found that both the local thermal conductivity and the overall thermal conductivity can be significantly modulated by these parameters.Specifically,in the supercritical states,the thermal conductivity of the confined fluid shows positive correlation to the bulk density as well as the temperature.However,when the bulk density is small,the thermal conductivity exhibits a decrease-increase transition as the temperature is increased.This is also the case in which the temperature is low.In fact,the decrease-increase transition in both the small-bulk-density and low-temperature cases arises from the capillary condensation in the pore.Furthermore,smaller pore width and/or stronger adsorption potential can raise the critical temperature for condensation,and then are beneficial to the enhancement of the thermal conductivity.These modulation behaviors of the local thermal conductivity lead immediately to the significant difference of the overall thermal conductivity in different phase regions. 展开更多
关键词 thermal conductivity nano-fluidic films density functional theory
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Density functional theory study of B- and Si-doped carbons and their adsorption interactions with sulfur compounds
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作者 Peng Guo Hong Zhang +1 位作者 Shuliang Dong Libao An 《Carbon Energy》 SCIE EI CAS CSCD 2024年第2期195-208,共14页
Understanding the adsorption interactions between carbon materials and sulfur compounds has far-reaching impacts,in addition to their well-known important role in energy storage and conversion,such as lithium-ion batt... Understanding the adsorption interactions between carbon materials and sulfur compounds has far-reaching impacts,in addition to their well-known important role in energy storage and conversion,such as lithium-ion batteries.In this paper,properties of intrinsic B or Si single-atom doped,and B-Si codoped graphene(GR)and graphdiyne(GDY)were investigated by using density functional theory-based calculations,in which the optimal doping configurations were explored for potential applications in adsorbing sulfur compounds.Results showed that both B or Si single-atom doping and B-Si codoping could substantially enhance the electron transport properties of GR and GDY,improving their surface activity.Notably,B and Si atoms displayed synergistic effects for the codoped configurations,where B-Si codoped GR/GDY exhibited much better performance in the adsorption of sulfurcontaining chemicals than single-atom doped systems.In addition,results demonstrated that,after B-Si codoping,the adsorption energy and charge transfer amounts of GDY with sulfur compounds were much larger than those of GR,indicating that B-Si codoped GDY might be a favorable material for more effectively interacting with sulfur reagents. 展开更多
关键词 ADSORPTION density functional theory DOPING graphdiyne GRAPHENE sulfur compounds
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Corrigendum to“Atomic-scale electromagnetic theory bridging optics in microscopic world and macroscopic world”
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作者 李志远 陈剑锋 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第2期586-586,共1页
The signs of the electric field markers in Figs.2 and 4 of the paper[Chin.Phys.B 32104211(2023)]have been corrected.These modifications do not affect the results derived in the paper.
关键词 CORRIGENDUM atomic-scale electromagnetic theory two-dimensional materials transfer matrix method
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Comparative study on phase transition behaviors of fractional molecular field theory and random-site Ising model
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作者 刘婷玉 赵薇 +3 位作者 王涛 安小冬 卫来 黄以能 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第3期536-541,共6页
Fractional molecular field theory(FMFT)is a phenomenological theory that describes phase transitions in crystals with randomly distributed components,such as the relaxor-ferroelectrics and spin glasses.In order to ver... Fractional molecular field theory(FMFT)is a phenomenological theory that describes phase transitions in crystals with randomly distributed components,such as the relaxor-ferroelectrics and spin glasses.In order to verify the feasibility of this theory,this paper fits it to the Monte Carlo simulations of specific heat and susceptibility versus temperature of two-dimensional(2D)random-site Ising model(2D-RSIM).The results indicate that the FMFT deviates from the 2D-RSIM significantly.The main reason for the deviation is that the 2D-RSIM is a typical system of component random distribution,where the real order parameter is spatially heterogeneous and has no symmetry of space translation,but the basic assumption of FMFT means that the parameter is spatially uniform and has symmetry of space translation. 展开更多
关键词 phase transition molecular field theory Ising model Monte Carlo
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Data Component:An Innovative Framework for Information Value Metrics in the Digital Economy
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作者 Tao Xiaoming Wang Yu +5 位作者 Peng Jieyang Zhao Yuelin Wang Yue Wang Youzheng Hu Chengsheng Lu Zhipeng 《China Communications》 SCIE CSCD 2024年第5期17-35,共19页
The increasing dependence on data highlights the need for a detailed understanding of its behavior,encompassing the challenges involved in processing and evaluating it.However,current research lacks a comprehensive st... The increasing dependence on data highlights the need for a detailed understanding of its behavior,encompassing the challenges involved in processing and evaluating it.However,current research lacks a comprehensive structure for measuring the worth of data elements,hindering effective navigation of the changing digital environment.This paper aims to fill this research gap by introducing the innovative concept of“data components.”It proposes a graphtheoretic representation model that presents a clear mathematical definition and demonstrates the superiority of data components over traditional processing methods.Additionally,the paper introduces an information measurement model that provides a way to calculate the information entropy of data components and establish their increased informational value.The paper also assesses the value of information,suggesting a pricing mechanism based on its significance.In conclusion,this paper establishes a robust framework for understanding and quantifying the value of implicit information in data,laying the groundwork for future research and practical applications. 展开更多
关键词 data component data element data governance data science information theory
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Distributed Matching Theory-Based Task Re-Allocating for Heterogeneous Multi-UAV Edge Computing
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作者 Yangang Wang Xianglin Wei +3 位作者 Hai Wang Yongyang Hu Kuang Zhao Jianhua Fan 《China Communications》 SCIE CSCD 2024年第1期260-278,共19页
Many efforts have been devoted to efficient task scheduling in Multi-Unmanned Aerial Vehicle(UAV)edge computing.However,the heterogeneity of UAV computation resource,and the task re-allocating between UAVs have not be... Many efforts have been devoted to efficient task scheduling in Multi-Unmanned Aerial Vehicle(UAV)edge computing.However,the heterogeneity of UAV computation resource,and the task re-allocating between UAVs have not been fully considered yet.Moreover,most existing works neglect the fact that a task can only be executed on the UAV equipped with its desired service function(SF).In this backdrop,this paper formulates the task scheduling problem as a multi-objective task scheduling problem,which aims at maximizing the task execution success ratio while minimizing the average weighted sum of all tasks’completion time and energy consumption.Optimizing three coupled goals in a realtime manner with the dynamic arrival of tasks hinders us from adopting existing methods,like machine learning-based solutions that require a long training time and tremendous pre-knowledge about the task arrival process,or heuristic-based ones that usually incur a long decision-making time.To tackle this problem in a distributed manner,we establish a matching theory framework,in which three conflicting goals are treated as the preferences of tasks,SFs and UAVs.Then,a Distributed Matching Theory-based Re-allocating(DiMaToRe)algorithm is put forward.We formally proved that a stable matching can be achieved by our proposal.Extensive simulation results show that Di Ma To Re algorithm outperforms benchmark algorithms under diverse parameter settings and has good robustness. 展开更多
关键词 edge computing HETEROGENEITY matching theory service function unmanned aerial vehicle
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The Fate of Supersymmetry in Quantum Field Theories
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作者 Risto Raitio 《Journal of High Energy Physics, Gravitation and Cosmology》 CAS 2024年第2期609-620,共12页
We analyze the significance of supersymmetry in two topological models and the standard model (SM). We conclude that the two topological field theory models favor hidden supersymmetry. The SM superpartners, instead, h... We analyze the significance of supersymmetry in two topological models and the standard model (SM). We conclude that the two topological field theory models favor hidden supersymmetry. The SM superpartners, instead, have not been found. 展开更多
关键词 Topological Field theory SUPERSYMMETRY Chern-Simons Model
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Foundations of the Scale-Symmetric Theory and the Illusory Total Width of the Off-Shell Higgs Bosons
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作者 Sylwester Kornowski 《Journal of High Energy Physics, Gravitation and Cosmology》 CAS 2024年第1期398-437,共40页
Here we present the foundations of the Scale-Symmetric Theory (SST), i.e. the fundamental phase transitions of the initial inflation field, the atom-like structure of baryons and different types of black holes. Within... Here we present the foundations of the Scale-Symmetric Theory (SST), i.e. the fundamental phase transitions of the initial inflation field, the atom-like structure of baryons and different types of black holes. Within SST we show that the transition from the nuclear strong interactions in the off-shell Higgs boson production to the nuclear weak interactions causes that the real total width of the Higgs boson from the Higgs line shape (i.e. 3.3 GeV) decreases to 4.3 MeV that is the illusory total width. Moreover, there appear some glueballs/condensates with the energy 3.3 GeV that accompany the production of the off-shell Higgs bosons. 展开更多
关键词 Scale-Symmetric theory Black Holes Higgs Boson
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Extreme value theory applied to the auroral electrojet indices
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作者 Si Chen Hong Yuan +2 位作者 Yong Wei Guang Yang FengZheng Yu 《Earth and Planetary Physics》 EI CAS CSCD 2024年第2期375-381,共7页
The study of extreme weather and space events has gained paramount importance in modern society owing to rapid advances in high technology.Understanding and describing exceptional occurrences plays a crucial role in m... The study of extreme weather and space events has gained paramount importance in modern society owing to rapid advances in high technology.Understanding and describing exceptional occurrences plays a crucial role in making decisive assessments of their potential impact on technical,economic,and social aspects in various fields.This research focuses on analyzing the hourly values of the auroral electrojet(AE)geomagnetic index from 1957 to 2019 by using the peak over threshold method in extreme value theory.By fitting the generalized Pareto distribution to extreme AE values,shape parameter indices were derived,revealing negative values that establish an upper bound for this time series.Consequently,it became evident that the AE values had reached a plateau,suggesting that extreme events exceeding the established upper limit are rare.As a result,although the need for diligent precautions to mitigate the consequences of such extreme events persists,surpassing the upper limit of AE values becomes increasingly challenging.It is also possible to observe an aurora in the middle-and low-latitude regions during the maximum period of the AE index. 展开更多
关键词 auroral electrojet indices extreme value theory extreme events
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Field Load Test Based SHM System Safety Standard Determination for Rigid Frame Bridge
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作者 Xilong Zheng Qiong Wang Di Guan 《Structural Durability & Health Monitoring》 EI 2024年第3期361-376,共16页
The deteriorated continuous rigid frame bridge is strengthened by external prestressing. Static loading tests wereconducted before and after the bridge rehabilitation to verify the effectiveness of the rehabilitation ... The deteriorated continuous rigid frame bridge is strengthened by external prestressing. Static loading tests wereconducted before and after the bridge rehabilitation to verify the effectiveness of the rehabilitation process. Thestiffness of the repaired bridge is improved, and the maximum deflection of the load test is reduced from 37.9 to27.6 mm. A bridge health monitoring system is installed after the bridge is reinforced. To achieve an easy assessmentof the bridge’s safety status by directly using transferred data, a real-time safety warning system is createdbased on a five-level safety standard. The threshold for each safety level will be determined by theoretical calculationsand the outcomes of static loading tests. The highest risk threshold will be set at the ultimate limit statevalue. The remaining levels, namely middle risk, low risk, and very low risk, will be determined usingreduction coefficients of 0.95, 0.9, and 0.8, respectively. 展开更多
关键词 Continuous rigid frame bridge REHABILITATION long-term monitoring field load test safety standard determination
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