To meet the requirements of electromagnetic(EM)theory and applied physics,this study presents an overview of the state-of-the-art research on obtaining the EM properties of media and points out potential solutions tha...To meet the requirements of electromagnetic(EM)theory and applied physics,this study presents an overview of the state-of-the-art research on obtaining the EM properties of media and points out potential solutions that can break through the bottlenecks of current methods.Firstly,based on the survey of three mainstream approaches for acquiring EM properties of media,we identify the difficulties when implementing them in realistic environments.With a focus on addressing these problems and challenges,we propose a novel paradigm for obtaining the EM properties of multi-type media in realistic environments.Particularly,within this paradigm,we describe the implementation approach of the key technology,namely“multipath extraction using heterogeneous wave propagation data in multi-spectrum cases”.Finally,the latest measurement and simulation results show that the EM properties of multi-type media in realistic environments can be precisely and efficiently acquired by the methodology proposed in this study.展开更多
Construction of LNG receiving terminals The scale of receiving terminals is expanding rapidly At the end of 1999,the state approved the Guangdong LNG Pilot Project,which opened the prelude to the construction of LNG r...Construction of LNG receiving terminals The scale of receiving terminals is expanding rapidly At the end of 1999,the state approved the Guangdong LNG Pilot Project,which opened the prelude to the construction of LNG receiving terminals.In 2006,China's first LNG receiving terminal,namely Dapeng LNG Receiving Terminal in Shenzhen,Guangdong Province,was put into operation,marking the beginning of the use of overseas natural gas in China.展开更多
Human pose estimation is a challenging task in computer vision.Most algorithms perform well in regular scenes,but lack good performance in occlusion scenarios.Therefore,we propose a multi-type feature fusion network b...Human pose estimation is a challenging task in computer vision.Most algorithms perform well in regular scenes,but lack good performance in occlusion scenarios.Therefore,we propose a multi-type feature fusion network based on importance weighting,which consists of three modules.In the first module,we propose a multi-resolution backbone with two feature enhancement sub-modules,which can extract features from different scales and enhance the feature expression ability.In the second module,we enhance the expressiveness of keypoint features by suppressing obstacle features and compensating for the unique and shared attributes of keypoints and topology.In the third module,we perform importance weighting on the adjacency matrix to enable it to describe the correlation among nodes,thereby improving the feature extraction ability.We conduct comparative experiments on the keypoint detection datasets of common objects in Context 2017(COCO2017),COCO-Wholebody and CrowdPose,achieving the accuracy of 78.9%,67.1%and 77.6%,respectively.Additionally,a series of ablation experiments are designed to show the performance of our work.Finally,we present the visualization of different scenarios to verify the effectiveness of our work.展开更多
In order to address the challenges encountered in visual navigation for asteroid landing using traditional point features,such as significant recognition and extraction errors,low computational efficiency,and limited ...In order to address the challenges encountered in visual navigation for asteroid landing using traditional point features,such as significant recognition and extraction errors,low computational efficiency,and limited navigation accuracy,a novel approach for multi-type fusion visual navigation is proposed.This method aims to overcome the limitations of single-type features and enhance navigation accuracy.Analytical criteria for selecting multi-type features are introduced,which simultaneously improve computational efficiency and system navigation accuracy.Concerning pose estimation,both absolute and relative pose estimation methods based on multi-type feature fusion are proposed,and multi-type feature normalization is established,which significantly improves system navigation accuracy and lays the groundwork for flexible application of joint absolute-relative estimation.The feasibility and effectiveness of the proposed method are validated through simulation experiments through 4769 Castalia.展开更多
In the context of the diversity of smart terminals,the unity of the root of trust becomes complicated,which not only affects the efficiency of trust propagation,but also poses a challenge to the security of the whole ...In the context of the diversity of smart terminals,the unity of the root of trust becomes complicated,which not only affects the efficiency of trust propagation,but also poses a challenge to the security of the whole system.In particular,the solidification of the root of trust in non-volatile memory(NVM)restricts the system’s dynamic updating capability,which is an obvious disadvantage in a rapidly changing security environment.To address this issue,this study proposes a novel approach to generate root security parameters using static random access memory(SRAM)physical unclonable functions(PUFs).SRAM PUFs,as a security primitive,show great potential in lightweight security solutions due to their inherent physical properties,low cost and scalability.However,the stability of SRAM PUFs in harsh environments is a key issue.These environmental conditions include extreme temperatures,high humidity,and strong electromagnetic radiation,all of which can affect the performance of SRAM PUFs.In order to ensure the stability of root safety parameters under these conditions,this study proposes an integrated approach that covers not only the acquisition of entropy sources,but also the implementation of algorithms and configuration management.In addition,this study develops a series of reliability-enhancing algorithms,including adaptive parameter selection,data preprocessing,auxiliary data generation,and error correction,which are essential for improving the performance of SRAM PUFs in harsh environments.Based on these techniques,this study establishes six types of secure parameter generation mechanisms,which not only improve the security of the system,but also enhance its adaptability in variable environments.Through a series of experiments,we verify the effectiveness of the proposed method.Under 10 different environmental conditions,our method is able to achieve full recovery of security data with an error rate of less than 25%,which proves the robustness and reliability of our method.These results not only provide strong evidence for the stability of SRAM PUFs in practical applications,but also provide a new direction for future research in the field of smart terminal security.展开更多
Automated guided vehicles(AGVs)are key equipment in automated container terminals(ACTs),and their operational efficiency can be impacted by conflicts and battery swapping.Additionally,AGVs have bidirectional transport...Automated guided vehicles(AGVs)are key equipment in automated container terminals(ACTs),and their operational efficiency can be impacted by conflicts and battery swapping.Additionally,AGVs have bidirectional transportation capabilities,allowing them tomove in the opposite directionwithout turning around,which helps reduce transportation time.This paper aims at the problem of AGV scheduling and bidirectional conflict-free routing with battery swapping in automated terminals.A bi-level mixed integer programming(MIP)model is proposed,taking into account task assignment,bidirectional conflict-free routing,and battery swapping.The upper model focuses on container task assignment and AGV battery swapping planning,while the lower model ensures conflict-free movement of AGVs.A double-threshold battery swapping strategy is introduced,allowing AGVs to utilize waiting time for loading for battery swapping.An improved differential evolution variable neighborhood search(IDE-VNS)algorithm is developed to solve the bi-level MIP model,aiming to minimize the completion time of all jobs.Experimental results demonstrate that compared to the differential evolution(DE)algorithm and the genetic algorithm(GA),the IDEVNS algorithmreduces fitness values by 44.49% and 45.22%,though it does increase computation time by 56.28% and 62.03%,respectively.Bidirectional transportation reduces the fitness value by an average of 10.97% when the container scale is small.As the container scale increases,the fitness value of bidirectional transportation gradually approaches that of unidirectional transportation.The results further show that the double-threshold battery swapping strategy enhances AGV utilization and reduces the fitness value.展开更多
This work presents a systematic analysis of proton-induced total ionizing dose(TID)effects in 1.2 k V silicon carbide(SiC)power devices with various edge termination structures.Three edge terminations including ring-a...This work presents a systematic analysis of proton-induced total ionizing dose(TID)effects in 1.2 k V silicon carbide(SiC)power devices with various edge termination structures.Three edge terminations including ring-assisted junction termination extension(RA-JTE),multiple floating zone JTE(MFZ-JTE),and field limiting rings(FLR)were fabricated and irradiated with45 Me V protons at fluences ranging from 1×10^(12) to 1×10^(14) cm^(-2).Experimental results,supported by TCAD simulations,show that the RA-JTE structure maintained stable breakdown performance with less than 1%variation due to its effective electric field redistribution by multiple P+rings.In contrast,MFZ-JTE and FLR exhibit breakdown voltage shifts of 6.1%and 15.2%,respectively,under the highest fluence.These results demonstrate the superior radiation tolerance of the RA-JTE structure under TID conditions and provide practical design guidance for radiation-hardened Si C power devices in space and other highradiation environments.展开更多
The carboxylation of alkynes with CO_(2) has attracted considerable interest due to the valorization of C1resources and atomic economy.Much effort focused on active metals(e.g.,Au,Ag,Cu),while the mechanistic role of ...The carboxylation of alkynes with CO_(2) has attracted considerable interest due to the valorization of C1resources and atomic economy.Much effort focused on active metals(e.g.,Au,Ag,Cu),while the mechanistic role of active supports,particularly the oxygen vacancy(O_(v)),in modulating C-H bond carboxylation remains unknown.Herein,ultra-small silver clusters and morphologically engineered CeO_(2) support(nanorods,nanocubes,and nano particles)were employed to construct Ag cluster/O_(v) synergistic catalyst,which exhibits variations in Oy concentration by an in situ auto-reduction method.The 0.197%Ag/CeO_(2)-NR catalyst exhibited a high reaction rate for the phenylacetylene carboxylation reaction and the maximal silver utilization efficiency.The characterization and DFT calculations demonstrated that vacancies enhanced CO_(2) adsorption via polarization-induced molecular bending and C-O bond elongation.Positively charged Ag clusters induced by metal-support interactions serve as deprotonation activation centers for alkynes.This synergistic interplay between dual active sites efficiently facilitates the C(sp)-H carboxylation with CO_(2).These findings offer critical insights for the rational selection of active supports in designing efficient C-H carboxylation catalysts.展开更多
To explore the best preparation process for terminal blend(TB)composite-modified asphalt and to filter its formulation with excellent performance,this study evaluates the performance of TB composite modified asphalt b...To explore the best preparation process for terminal blend(TB)composite-modified asphalt and to filter its formulation with excellent performance,this study evaluates the performance of TB composite modified asphalt by physical property index,microscopic morphology,rheological testing,and infrared spectroscopy on multiple scales.The results show that the best preparation process for TB-modified asphalt is stirring at 260℃ for 4 h at 400 rpm,which significantly reduces the modification time of the asphalt.From a physical property viewpoint,the TB composite-modified asphalt sample with 5% styrene-butadiene-styrene(SBS)+1% aromatics+0.1% sulfur exhibits high-comprehensive,high-and low-temperature properties.More-over,its crosslinked mesh structure comprises black rubber particles uniformly interwoven in the middle,which further enhances the performance of the asphalt and results in an excellent performance formulation.In addition,the sample with 5%SBS content has a higher G*value and smaller δ value than that with 3%SBS content,indicating that its high-temperature resistance is improved.The effect of adding 3%SBS content on the viscoelastic ratio is,to some extent,less than that caused by 20% rubber powder.展开更多
In this paper,a unified terminal sliding mode(UTSM)control method is proposed for second-order nonlinear systems with uncertainties and disturbances.It is seen that the newly defined terminal sliding surface is integr...In this paper,a unified terminal sliding mode(UTSM)control method is proposed for second-order nonlinear systems with uncertainties and disturbances.It is seen that the newly defined terminal sliding surface is integrated with both conventional and fast terminal sliding mode and exhibits design advantages such as a variable exponent,adjustable sliding mode parameters,and chattering-alleviation effect.The inherent dynamic properties of the closed-loop systems with the UTSM control are discussed in detail via the phase plane and Lyapunov stability theory.Both numerical simulations and experimental results show the flexible sliding manifold design,strong robustness against uncertain dynamics,and effective attenuation of chattering phenomenon.展开更多
The task assignment problem of multiple heterogeneous unmanned aerial vehicles （UAVs）, concerned with cooperative decision making and control, is studied in this paper. The heterogeneous vehicles have different oper...The task assignment problem of multiple heterogeneous unmanned aerial vehicles （UAVs）, concerned with cooperative decision making and control, is studied in this paper. The heterogeneous vehicles have different operational capabilities and kinematic constraints, and carry limited resources （e.g., weapons） onboard. They are designated to perform multiple consecutive tasks cooperatively on multiple ground targets. The problem becomes much more complicated because of these terms of heterogeneity. In order to tackle the challenge, we modify the former genetic algorithm with multi-type genes to stochastically search a best solution. Genes of chromo- somes are different, and they are assorted into several types according to the tasks that must be performed on targets. Different types of genes are processed specifically in the improved genetic operators including initialization, crossover, and mutation. We also present a mirror representation of vehicles to deal with the limited resource constraint. Feasible chromosomes that vehicles could perform tasks using their limited resources under the assignment are created and evolved by genetic operators. The effect of the proposed algorithm is demonstrated in numerical simulations. The results show that it effectively provides good feasible solutions and finds an optimal one.展开更多
The time dependent vehicle routing problem with time windows(TDVRPTW)is considered.A multi-type ant system(MTAS)algorithm hybridized with the ant colony system(ACS)and the max-min ant system(MMAS)algorithms is propose...The time dependent vehicle routing problem with time windows(TDVRPTW)is considered.A multi-type ant system(MTAS)algorithm hybridized with the ant colony system(ACS)and the max-min ant system(MMAS)algorithms is proposed.This combination absorbs the merits of the two algorithms in solutions construction and optimization separately.In order to improve the efficiency of the insertion procedure,a nearest neighbor selection(NNS)mechanism,an insertion local search procedure and a local optimization procedure are specified in detail.And in order to find a balance between good scouting performance and fast convergence rate,an adaptive pheromone updating strategy is proposed in the MTAS.Computational results confirm the MTAS algorithm's good performance with all these strategies on classic vehicle routing problem with time windows(VRPTW)benchmark instances and the TDVRPTW instances,and some better results especially for the number of vehicles and travel times of the best solutions are obtained in comparison with the previous research.展开更多
This study discusses a yard planning system,which considers various resources such as storage space,yard cranes,and traffic areas in container terminals.The system is based on the function for estimating resource requ...This study discusses a yard planning system,which considers various resources such as storage space,yard cranes,and traffic areas in container terminals.The system is based on the function for estimating resource requirements of yard plans.For a given yard plan,the proposed system allows planners to check the feasibility of the plan which requires a certain amount of workload of resources in related blocks during a planning horizon.The yard planning system in this study is aimed at balancing workloads among the blocks and providing the ability to modify current yard plans by detecting blocks and periods with overloaded workloads.The system implements its planning function in a distributed manner in which planners construct yard plans under their individual control and send and receive only limited necessary information for the negotiation.展开更多
Sodium-ion batteries stand a chance of enabling fast charging ability and long lifespan while operating at low temperature(low-T).However,sluggish kinetics and aggravated dendrites present two major challenges for ano...Sodium-ion batteries stand a chance of enabling fast charging ability and long lifespan while operating at low temperature(low-T).However,sluggish kinetics and aggravated dendrites present two major challenges for anodes to achieve the goal at low-T.Herein,we propose an interlayer confined strategy for tailoring nitrogen terminals on Ti_(3)C_(2) MXene(Ti_(3)C_(2)-N_(funct)) to address these issues.The introduction of nitrogen terminals endows Ti_(3)C_(2)-N_(funct) with large interlayer space and charge redistribution,improved conductivity and sufficient adsorption sites for Na^(+),which improves the possibility of Ti_(3)C_(2) for accommodating more Na atoms,further enhancing the Na^(+) storage capability of Ti_(3)C_(2).As revealed,Ti_(3)C_(2)-N_(funct) not only possesses a lower Na-ion diffusion energy barrier and charge trans-fer activation energy,but also exhibits Na^(+)-solvent co-intercalation behavior to circumvent a high de-solvation energy barrier at low-T.Besides,the solid electrolyte interface dominated by inorganic com-pounds is more beneficial for the Na^(+)transfer at the electrode/electrolyte interface.Compared with of the unmodified sample,Ti_(3)C_(2)-Nfunct exhibits a twofold capacity(201 mAh g^(-1)),fast-charging ability(18 min at 80% capacity retention),and great superiority in cycle life(80.9%@5000 cycles)at -25℃.When coupling with Na_(3)V_(2)(PO_(4))_(2)F_(3) cathode,the Ti_(3)C_(2)-N_(funct)//NVPF exhibits high energy density and cycle stability at -25℃.展开更多
Different types of lightning air terminals have been designed over the years.Concern regarding the effect of different types of air terminals,especially the early streamer emission(ESE)-type,remains controversial.This...Different types of lightning air terminals have been designed over the years.Concern regarding the effect of different types of air terminals,especially the early streamer emission(ESE)-type,remains controversial.This paper describes the discharge characteristics of different types of air terminals,two of which are quite similar to the ESE-type dynasphere,and concludes that the tested non-standard air terminals have discharge characteristics similar to those of Franklin rods and that their lightning protection performance should be similar.展开更多
Estimation of lateral displacement and acceleration responses is essential to assess safety and serviceability of high-rise buildings under dynamic loadings including earthquake excitations. However, the measurement i...Estimation of lateral displacement and acceleration responses is essential to assess safety and serviceability of high-rise buildings under dynamic loadings including earthquake excitations. However, the measurement information from the limited number of sensors installed in a building structure is often insufficient for the complete structural performance assessment. An integrated multi-type sensor placement and response reconstruction method has thus been proposed by the authors to tackle this problem. To validate the feasibility and effectiveness of the proposed method, an experimental investigation using a cantilever beam with multi-type sensors is performed and reported in this paper. The experimental setup is first introduced. The finite element modelling and model updating of the cantilever beam are then performed. The optimal sensor placement for the best response reconstruction is determined by the proposed method based on the updated FE model of the beam. After the sensors are installed on the physical cantilever beam, a number of experiments are carried out. The responses at key locations are reconstructed and compared with the measured ones. The reconstructed responses achieve a good match with the measured ones, manifesting the feasibility and effectiveness of the proposed method. Besides, the proposed method is also examined for the cases of different excitations and unknown excitation, and the results prove the proposed method to be robust and effective. The superiority of the optimized sensor placement scheme is finally demonstrated through comparison with two other different sensor placement schemes： the accelerometer-only scheme and non-optimal sensor placement scheme. The proposed method can be applied to high-rise buildings for seismic performance assessment.展开更多
LEO satellite communication network has a large number of satellites distributed in low orbits,which leads to multiple coverage of many areas on the ground.It is hard work to describe and evaluate the reliability of L...LEO satellite communication network has a large number of satellites distributed in low orbits,which leads to multiple coverage of many areas on the ground.It is hard work to describe and evaluate the reliability of LEO satellite communication network.To solve this problem,the reliability of all-user terminals in LEO satellite communication network is defined,and the corresponding reliability evaluation method is proposed in the paper.Due to the large scale of the interstellar network,a modular reduction algorithm using the modular network instead of the original network for state decomposition is proposed in this paper.Case study shows that the calculation time of the proposed method is equivalent to 6.28%of the original state space decomposition algorithm.On this basis,the reliability of LEO satellite communication network is further analyzed.It is found that the reliability of LEO satellite network was more sensitive to the reliability of Inter-Satellite link and the satisfaction of global coverage in the early stage,and it is more sensitive to the reliability of the satellite in the later stage.The satellite-ground link has a relatively constant impact on of LEO satellite network.展开更多
Low volume of produced wastewater and specific regional, environmental and economic condition in small communities determines the methods of treatment of sewage in such communities including shorelines of Bandar Abbas...Low volume of produced wastewater and specific regional, environmental and economic condition in small communities determines the methods of treatment of sewage in such communities including shorelines of Bandar Abbas, Bushehr, Imam Khomeini Harbor and Chabahar Harbor. Ineffective methods of treating and sewing wastewater in aforesaid terminals as well as limitations of methods of wastewater treatment such as high level of underground waters doubled the necessity of considering alternative methods. In this paper, investigation of current conditions was performed through field observations and data collection regarding wastewater production in terminals and determination of qualitative specifications using sampling and carrying out pH, TSS, COD, BOD and temperature tests from inlet to outlet of available sewage system of abovementioned terminals and comparison with environmental organization standards corresponding to wastewater sewage and it was found out that conditions of available systems of wastewater treatment are not suitable. In this regard, modifying solutions for the sake of improving performance of systems of wastewater treatment of terminals is presented in this research. Finally, for wastewater treatment system of Bandar Abbas terminal, if there is no limitation for allocating lands, it is recommended to use artificial canebrake system with underground flow.展开更多
An optimization model for scheduling of quay cranes (QCs) and yard trailers was proposed to improve the overall efficiency of container terminals. To implement this model, a two-phase tabu search algorithm was designe...An optimization model for scheduling of quay cranes (QCs) and yard trailers was proposed to improve the overall efficiency of container terminals. To implement this model, a two-phase tabu search algorithm was designed. In the QCs scheduling phase of the algorithm, a search was performed to determine a good QC unloading operation order. For each QC unloading operation order generated during the QC's scheduling phase, another search was run to obtain a good yard trailer routing for the given QC's unloading order. Using this information, the time required for the operation was estimated, then the time of return to availability of the units was fed back to the QC scheduler. Numerical tests show that the two-phase Tabu Search algorithm searches the solution space efficiently, decreases the empty distance yard trailers must travel, decreases the number of trailers needed, and thereby reduces time and costs and improves the integration and reliability of container terminal operation systems.展开更多
A spontaneous mutation in the Albino Swiss (AS) rat has been shown to be a single point mutation (agu) in the gene coding for the gamma isoform of protein kinase C (PKC-γ). The characteristics of the mutant include m...A spontaneous mutation in the Albino Swiss (AS) rat has been shown to be a single point mutation (agu) in the gene coding for the gamma isoform of protein kinase C (PKC-γ). The characteristics of the mutant include movement disorders, a failure to release dopamine in the striatum and elevations of molecules such as parkin and ubiquitin in the substantia nigra pars compacta (SNC). This present study examined SNC cell bodies and dopaminergic synaptic terminals within the caudate-putamen. Cell volume and nuclear volume were reduced in the AS/AGU mutant compared to the AS control, but the volume fractions of mitochondria and rough endoplasmic reticulum were significantly higher. No Lewy bodies were present in the mutant, although microglia were found adjacent to some SNC cells. Dopaminergic terminals were identified in the caudate-putamen by electron microscopy with low-glutaraldehyde fixation and immunohistochemistry for tyrosine hydroxylase using immuno-gold visualisation. AS/AGU mutant rats had less than half of the synaptic vesicles of AS controls;this was not only true of “readily-releasable” zones adjacent to the synaptic cleft but also “storage pool” zones. The findings support the hypothesis that the initial bar to dopamine availability in the striatum is the reduced release, with nigral cell death being a later phenomenon.展开更多
基金supported by the Beijing Natural Science Foundation(No.L212029)the National Natural Science Foundation of China(No.62271043).
文摘To meet the requirements of electromagnetic(EM)theory and applied physics,this study presents an overview of the state-of-the-art research on obtaining the EM properties of media and points out potential solutions that can break through the bottlenecks of current methods.Firstly,based on the survey of three mainstream approaches for acquiring EM properties of media,we identify the difficulties when implementing them in realistic environments.With a focus on addressing these problems and challenges,we propose a novel paradigm for obtaining the EM properties of multi-type media in realistic environments.Particularly,within this paradigm,we describe the implementation approach of the key technology,namely“multipath extraction using heterogeneous wave propagation data in multi-spectrum cases”.Finally,the latest measurement and simulation results show that the EM properties of multi-type media in realistic environments can be precisely and efficiently acquired by the methodology proposed in this study.
文摘Construction of LNG receiving terminals The scale of receiving terminals is expanding rapidly At the end of 1999,the state approved the Guangdong LNG Pilot Project,which opened the prelude to the construction of LNG receiving terminals.In 2006,China's first LNG receiving terminal,namely Dapeng LNG Receiving Terminal in Shenzhen,Guangdong Province,was put into operation,marking the beginning of the use of overseas natural gas in China.
基金supported by Ministry of Education Industry-University Cooperation and Collaborative Education Project(China)(220603231024713).
文摘Human pose estimation is a challenging task in computer vision.Most algorithms perform well in regular scenes,but lack good performance in occlusion scenarios.Therefore,we propose a multi-type feature fusion network based on importance weighting,which consists of three modules.In the first module,we propose a multi-resolution backbone with two feature enhancement sub-modules,which can extract features from different scales and enhance the feature expression ability.In the second module,we enhance the expressiveness of keypoint features by suppressing obstacle features and compensating for the unique and shared attributes of keypoints and topology.In the third module,we perform importance weighting on the adjacency matrix to enable it to describe the correlation among nodes,thereby improving the feature extraction ability.We conduct comparative experiments on the keypoint detection datasets of common objects in Context 2017(COCO2017),COCO-Wholebody and CrowdPose,achieving the accuracy of 78.9%,67.1%and 77.6%,respectively.Additionally,a series of ablation experiments are designed to show the performance of our work.Finally,we present the visualization of different scenarios to verify the effectiveness of our work.
基金supported by the National Natural Science Foundation of China(No.U2037602)。
文摘In order to address the challenges encountered in visual navigation for asteroid landing using traditional point features,such as significant recognition and extraction errors,low computational efficiency,and limited navigation accuracy,a novel approach for multi-type fusion visual navigation is proposed.This method aims to overcome the limitations of single-type features and enhance navigation accuracy.Analytical criteria for selecting multi-type features are introduced,which simultaneously improve computational efficiency and system navigation accuracy.Concerning pose estimation,both absolute and relative pose estimation methods based on multi-type feature fusion are proposed,and multi-type feature normalization is established,which significantly improves system navigation accuracy and lays the groundwork for flexible application of joint absolute-relative estimation.The feasibility and effectiveness of the proposed method are validated through simulation experiments through 4769 Castalia.
基金supported by National key Research and Development Program“Security Protection Technology for Critical Information Infrastructure of Distribution Network”(2022YFB3105100).
文摘In the context of the diversity of smart terminals,the unity of the root of trust becomes complicated,which not only affects the efficiency of trust propagation,but also poses a challenge to the security of the whole system.In particular,the solidification of the root of trust in non-volatile memory(NVM)restricts the system’s dynamic updating capability,which is an obvious disadvantage in a rapidly changing security environment.To address this issue,this study proposes a novel approach to generate root security parameters using static random access memory(SRAM)physical unclonable functions(PUFs).SRAM PUFs,as a security primitive,show great potential in lightweight security solutions due to their inherent physical properties,low cost and scalability.However,the stability of SRAM PUFs in harsh environments is a key issue.These environmental conditions include extreme temperatures,high humidity,and strong electromagnetic radiation,all of which can affect the performance of SRAM PUFs.In order to ensure the stability of root safety parameters under these conditions,this study proposes an integrated approach that covers not only the acquisition of entropy sources,but also the implementation of algorithms and configuration management.In addition,this study develops a series of reliability-enhancing algorithms,including adaptive parameter selection,data preprocessing,auxiliary data generation,and error correction,which are essential for improving the performance of SRAM PUFs in harsh environments.Based on these techniques,this study establishes six types of secure parameter generation mechanisms,which not only improve the security of the system,but also enhance its adaptability in variable environments.Through a series of experiments,we verify the effectiveness of the proposed method.Under 10 different environmental conditions,our method is able to achieve full recovery of security data with an error rate of less than 25%,which proves the robustness and reliability of our method.These results not only provide strong evidence for the stability of SRAM PUFs in practical applications,but also provide a new direction for future research in the field of smart terminal security.
基金supported by National Natural Science Foundation of China(No.62073212)Shanghai Science and Technology Commission(No.23ZR1426600).
文摘Automated guided vehicles(AGVs)are key equipment in automated container terminals(ACTs),and their operational efficiency can be impacted by conflicts and battery swapping.Additionally,AGVs have bidirectional transportation capabilities,allowing them tomove in the opposite directionwithout turning around,which helps reduce transportation time.This paper aims at the problem of AGV scheduling and bidirectional conflict-free routing with battery swapping in automated terminals.A bi-level mixed integer programming(MIP)model is proposed,taking into account task assignment,bidirectional conflict-free routing,and battery swapping.The upper model focuses on container task assignment and AGV battery swapping planning,while the lower model ensures conflict-free movement of AGVs.A double-threshold battery swapping strategy is introduced,allowing AGVs to utilize waiting time for loading for battery swapping.An improved differential evolution variable neighborhood search(IDE-VNS)algorithm is developed to solve the bi-level MIP model,aiming to minimize the completion time of all jobs.Experimental results demonstrate that compared to the differential evolution(DE)algorithm and the genetic algorithm(GA),the IDEVNS algorithmreduces fitness values by 44.49% and 45.22%,though it does increase computation time by 56.28% and 62.03%,respectively.Bidirectional transportation reduces the fitness value by an average of 10.97% when the container scale is small.As the container scale increases,the fitness value of bidirectional transportation gradually approaches that of unidirectional transportation.The results further show that the double-threshold battery swapping strategy enhances AGV utilization and reduces the fitness value.
基金supported by the IITP(Institute for Information&Communications Technology Planning&Evaluation)under the ITRC(Information Technology Research Center)support program(IITP-2025-RS-2024-00438288)grant funded by the Korea government(MSIT)+1 种基金National Research Council of Science&Technology(NST)grant by the MSIT(Aerospace Semiconductor Strategy Research Project No.GTL25051-000)supported by the IC Design Education Center(IDEC),Korea。
文摘This work presents a systematic analysis of proton-induced total ionizing dose(TID)effects in 1.2 k V silicon carbide(SiC)power devices with various edge termination structures.Three edge terminations including ring-assisted junction termination extension(RA-JTE),multiple floating zone JTE(MFZ-JTE),and field limiting rings(FLR)were fabricated and irradiated with45 Me V protons at fluences ranging from 1×10^(12) to 1×10^(14) cm^(-2).Experimental results,supported by TCAD simulations,show that the RA-JTE structure maintained stable breakdown performance with less than 1%variation due to its effective electric field redistribution by multiple P+rings.In contrast,MFZ-JTE and FLR exhibit breakdown voltage shifts of 6.1%and 15.2%,respectively,under the highest fluence.These results demonstrate the superior radiation tolerance of the RA-JTE structure under TID conditions and provide practical design guidance for radiation-hardened Si C power devices in space and other highradiation environments.
基金financially supported by the National Natural Science Foundation of China(22102194)the Science and Technology Plan of Gansu Province(24JRRA067,23ZDFA016)the Youth Innovation Promotion Association of CAS(2022427)。
文摘The carboxylation of alkynes with CO_(2) has attracted considerable interest due to the valorization of C1resources and atomic economy.Much effort focused on active metals(e.g.,Au,Ag,Cu),while the mechanistic role of active supports,particularly the oxygen vacancy(O_(v)),in modulating C-H bond carboxylation remains unknown.Herein,ultra-small silver clusters and morphologically engineered CeO_(2) support(nanorods,nanocubes,and nano particles)were employed to construct Ag cluster/O_(v) synergistic catalyst,which exhibits variations in Oy concentration by an in situ auto-reduction method.The 0.197%Ag/CeO_(2)-NR catalyst exhibited a high reaction rate for the phenylacetylene carboxylation reaction and the maximal silver utilization efficiency.The characterization and DFT calculations demonstrated that vacancies enhanced CO_(2) adsorption via polarization-induced molecular bending and C-O bond elongation.Positively charged Ag clusters induced by metal-support interactions serve as deprotonation activation centers for alkynes.This synergistic interplay between dual active sites efficiently facilitates the C(sp)-H carboxylation with CO_(2).These findings offer critical insights for the rational selection of active supports in designing efficient C-H carboxylation catalysts.
基金Funded by the National Natural Science Foundation of China(No.52278446)。
文摘To explore the best preparation process for terminal blend(TB)composite-modified asphalt and to filter its formulation with excellent performance,this study evaluates the performance of TB composite modified asphalt by physical property index,microscopic morphology,rheological testing,and infrared spectroscopy on multiple scales.The results show that the best preparation process for TB-modified asphalt is stirring at 260℃ for 4 h at 400 rpm,which significantly reduces the modification time of the asphalt.From a physical property viewpoint,the TB composite-modified asphalt sample with 5% styrene-butadiene-styrene(SBS)+1% aromatics+0.1% sulfur exhibits high-comprehensive,high-and low-temperature properties.More-over,its crosslinked mesh structure comprises black rubber particles uniformly interwoven in the middle,which further enhances the performance of the asphalt and results in an excellent performance formulation.In addition,the sample with 5%SBS content has a higher G*value and smaller δ value than that with 3%SBS content,indicating that its high-temperature resistance is improved.The effect of adding 3%SBS content on the viscoelastic ratio is,to some extent,less than that caused by 20% rubber powder.
基金supported by the National Natural Science Foundation of China(62473337,62003305)the Key Research and Development Program of Zhejiang Province(2024C03040,2022C03029)the Leading Innovative and Entrepreneur Team Introduction Program of Zhejiang Province(2023R01006)。
文摘In this paper,a unified terminal sliding mode(UTSM)control method is proposed for second-order nonlinear systems with uncertainties and disturbances.It is seen that the newly defined terminal sliding surface is integrated with both conventional and fast terminal sliding mode and exhibits design advantages such as a variable exponent,adjustable sliding mode parameters,and chattering-alleviation effect.The inherent dynamic properties of the closed-loop systems with the UTSM control are discussed in detail via the phase plane and Lyapunov stability theory.Both numerical simulations and experimental results show the flexible sliding manifold design,strong robustness against uncertain dynamics,and effective attenuation of chattering phenomenon.
文摘The task assignment problem of multiple heterogeneous unmanned aerial vehicles （UAVs）, concerned with cooperative decision making and control, is studied in this paper. The heterogeneous vehicles have different operational capabilities and kinematic constraints, and carry limited resources （e.g., weapons） onboard. They are designated to perform multiple consecutive tasks cooperatively on multiple ground targets. The problem becomes much more complicated because of these terms of heterogeneity. In order to tackle the challenge, we modify the former genetic algorithm with multi-type genes to stochastically search a best solution. Genes of chromo- somes are different, and they are assorted into several types according to the tasks that must be performed on targets. Different types of genes are processed specifically in the improved genetic operators including initialization, crossover, and mutation. We also present a mirror representation of vehicles to deal with the limited resource constraint. Feasible chromosomes that vehicles could perform tasks using their limited resources under the assignment are created and evolved by genetic operators. The effect of the proposed algorithm is demonstrated in numerical simulations. The results show that it effectively provides good feasible solutions and finds an optimal one.
文摘The time dependent vehicle routing problem with time windows(TDVRPTW)is considered.A multi-type ant system(MTAS)algorithm hybridized with the ant colony system(ACS)and the max-min ant system(MMAS)algorithms is proposed.This combination absorbs the merits of the two algorithms in solutions construction and optimization separately.In order to improve the efficiency of the insertion procedure,a nearest neighbor selection(NNS)mechanism,an insertion local search procedure and a local optimization procedure are specified in detail.And in order to find a balance between good scouting performance and fast convergence rate,an adaptive pheromone updating strategy is proposed in the MTAS.Computational results confirm the MTAS algorithm's good performance with all these strategies on classic vehicle routing problem with time windows(VRPTW)benchmark instances and the TDVRPTW instances,and some better results especially for the number of vehicles and travel times of the best solutions are obtained in comparison with the previous research.
基金Project supported by the Korean Ministry of Education,Science and Technology Grant (the Regional Core Research Program/Institute of Logistics Information Technology)
文摘This study discusses a yard planning system,which considers various resources such as storage space,yard cranes,and traffic areas in container terminals.The system is based on the function for estimating resource requirements of yard plans.For a given yard plan,the proposed system allows planners to check the feasibility of the plan which requires a certain amount of workload of resources in related blocks during a planning horizon.The yard planning system in this study is aimed at balancing workloads among the blocks and providing the ability to modify current yard plans by detecting blocks and periods with overloaded workloads.The system implements its planning function in a distributed manner in which planners construct yard plans under their individual control and send and receive only limited necessary information for the negotiation.
基金the National Natural Sci-ence Foundation of China(Grant Nos.21673064,51902072 and 22109033)Heilongjiang Touyan Team(Grant No.HITTY-20190033)+1 种基金Fundamental Research Funds for the Central Universities(Grant Nos.HIT.NSRIF.2019040 and 2019041)State Key Laboratory of Urban Water Resource and Environment(Harbin Institute of Technology)(Grant No.2020 DX11).
文摘Sodium-ion batteries stand a chance of enabling fast charging ability and long lifespan while operating at low temperature(low-T).However,sluggish kinetics and aggravated dendrites present two major challenges for anodes to achieve the goal at low-T.Herein,we propose an interlayer confined strategy for tailoring nitrogen terminals on Ti_(3)C_(2) MXene(Ti_(3)C_(2)-N_(funct)) to address these issues.The introduction of nitrogen terminals endows Ti_(3)C_(2)-N_(funct) with large interlayer space and charge redistribution,improved conductivity and sufficient adsorption sites for Na^(+),which improves the possibility of Ti_(3)C_(2) for accommodating more Na atoms,further enhancing the Na^(+) storage capability of Ti_(3)C_(2).As revealed,Ti_(3)C_(2)-N_(funct) not only possesses a lower Na-ion diffusion energy barrier and charge trans-fer activation energy,but also exhibits Na^(+)-solvent co-intercalation behavior to circumvent a high de-solvation energy barrier at low-T.Besides,the solid electrolyte interface dominated by inorganic com-pounds is more beneficial for the Na^(+)transfer at the electrode/electrolyte interface.Compared with of the unmodified sample,Ti_(3)C_(2)-Nfunct exhibits a twofold capacity(201 mAh g^(-1)),fast-charging ability(18 min at 80% capacity retention),and great superiority in cycle life(80.9%@5000 cycles)at -25℃.When coupling with Na_(3)V_(2)(PO_(4))_(2)F_(3) cathode,the Ti_(3)C_(2)-N_(funct)//NVPF exhibits high energy density and cycle stability at -25℃.
基金partly supported by National Natural Science Foundation of China(No.51577098)the State Grid Corporation of China,and China Southern Power Grid
文摘Different types of lightning air terminals have been designed over the years.Concern regarding the effect of different types of air terminals,especially the early streamer emission(ESE)-type,remains controversial.This paper describes the discharge characteristics of different types of air terminals,two of which are quite similar to the ESE-type dynasphere,and concludes that the tested non-standard air terminals have discharge characteristics similar to those of Franklin rods and that their lightning protection performance should be similar.
基金The Hong Kong Polytechnic University through the group project "Fundamentals of Earthquake Engineering for Hong Kong"(4-ZZCD)the collaborative research project with Beijing University of Technology(4-ZZGD)
文摘Estimation of lateral displacement and acceleration responses is essential to assess safety and serviceability of high-rise buildings under dynamic loadings including earthquake excitations. However, the measurement information from the limited number of sensors installed in a building structure is often insufficient for the complete structural performance assessment. An integrated multi-type sensor placement and response reconstruction method has thus been proposed by the authors to tackle this problem. To validate the feasibility and effectiveness of the proposed method, an experimental investigation using a cantilever beam with multi-type sensors is performed and reported in this paper. The experimental setup is first introduced. The finite element modelling and model updating of the cantilever beam are then performed. The optimal sensor placement for the best response reconstruction is determined by the proposed method based on the updated FE model of the beam. After the sensors are installed on the physical cantilever beam, a number of experiments are carried out. The responses at key locations are reconstructed and compared with the measured ones. The reconstructed responses achieve a good match with the measured ones, manifesting the feasibility and effectiveness of the proposed method. Besides, the proposed method is also examined for the cases of different excitations and unknown excitation, and the results prove the proposed method to be robust and effective. The superiority of the optimized sensor placement scheme is finally demonstrated through comparison with two other different sensor placement schemes： the accelerometer-only scheme and non-optimal sensor placement scheme. The proposed method can be applied to high-rise buildings for seismic performance assessment.
基金supported by the projects of the National Natural Science Foundation of China entitled“Reliability growth evaluation and prediction model of large aerospace(72071111)”“Reverse multi variable CF-GERT model and its application for complex equipment development schedule under the background of multi project mixed batch(71801127)”+4 种基金“Research on network of reliability growth of complex equipment under the background of collaborative development(71671091)”supported by a joint project of both the NSFC and the RS of the UK entitled“On grey dynamic scheduling model of complex product based on sensing information of internet of things”(71811530338)support of the Fundamental Research Funds for the Central Universities of China(NC2019003,NP2019104)Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX210239)support of a project of Intelligence Introduction Base of the Ministry of Science and Technology(G20190010178).
文摘LEO satellite communication network has a large number of satellites distributed in low orbits,which leads to multiple coverage of many areas on the ground.It is hard work to describe and evaluate the reliability of LEO satellite communication network.To solve this problem,the reliability of all-user terminals in LEO satellite communication network is defined,and the corresponding reliability evaluation method is proposed in the paper.Due to the large scale of the interstellar network,a modular reduction algorithm using the modular network instead of the original network for state decomposition is proposed in this paper.Case study shows that the calculation time of the proposed method is equivalent to 6.28%of the original state space decomposition algorithm.On this basis,the reliability of LEO satellite communication network is further analyzed.It is found that the reliability of LEO satellite network was more sensitive to the reliability of Inter-Satellite link and the satisfaction of global coverage in the early stage,and it is more sensitive to the reliability of the satellite in the later stage.The satellite-ground link has a relatively constant impact on of LEO satellite network.
文摘Low volume of produced wastewater and specific regional, environmental and economic condition in small communities determines the methods of treatment of sewage in such communities including shorelines of Bandar Abbas, Bushehr, Imam Khomeini Harbor and Chabahar Harbor. Ineffective methods of treating and sewing wastewater in aforesaid terminals as well as limitations of methods of wastewater treatment such as high level of underground waters doubled the necessity of considering alternative methods. In this paper, investigation of current conditions was performed through field observations and data collection regarding wastewater production in terminals and determination of qualitative specifications using sampling and carrying out pH, TSS, COD, BOD and temperature tests from inlet to outlet of available sewage system of abovementioned terminals and comparison with environmental organization standards corresponding to wastewater sewage and it was found out that conditions of available systems of wastewater treatment are not suitable. In this regard, modifying solutions for the sake of improving performance of systems of wastewater treatment of terminals is presented in this research. Finally, for wastewater treatment system of Bandar Abbas terminal, if there is no limitation for allocating lands, it is recommended to use artificial canebrake system with underground flow.
文摘An optimization model for scheduling of quay cranes (QCs) and yard trailers was proposed to improve the overall efficiency of container terminals. To implement this model, a two-phase tabu search algorithm was designed. In the QCs scheduling phase of the algorithm, a search was performed to determine a good QC unloading operation order. For each QC unloading operation order generated during the QC's scheduling phase, another search was run to obtain a good yard trailer routing for the given QC's unloading order. Using this information, the time required for the operation was estimated, then the time of return to availability of the units was fed back to the QC scheduler. Numerical tests show that the two-phase Tabu Search algorithm searches the solution space efficiently, decreases the empty distance yard trailers must travel, decreases the number of trailers needed, and thereby reduces time and costs and improves the integration and reliability of container terminal operation systems.
文摘A spontaneous mutation in the Albino Swiss (AS) rat has been shown to be a single point mutation (agu) in the gene coding for the gamma isoform of protein kinase C (PKC-γ). The characteristics of the mutant include movement disorders, a failure to release dopamine in the striatum and elevations of molecules such as parkin and ubiquitin in the substantia nigra pars compacta (SNC). This present study examined SNC cell bodies and dopaminergic synaptic terminals within the caudate-putamen. Cell volume and nuclear volume were reduced in the AS/AGU mutant compared to the AS control, but the volume fractions of mitochondria and rough endoplasmic reticulum were significantly higher. No Lewy bodies were present in the mutant, although microglia were found adjacent to some SNC cells. Dopaminergic terminals were identified in the caudate-putamen by electron microscopy with low-glutaraldehyde fixation and immunohistochemistry for tyrosine hydroxylase using immuno-gold visualisation. AS/AGU mutant rats had less than half of the synaptic vesicles of AS controls;this was not only true of “readily-releasable” zones adjacent to the synaptic cleft but also “storage pool” zones. The findings support the hypothesis that the initial bar to dopamine availability in the striatum is the reduced release, with nigral cell death being a later phenomenon.
