The China Expo Forum for International Cooperation(CEFCO)2026 was held in Wuhan,Hubei Province,China,on January 22.The opening ceremony was attended by Li Qing Shuang,Vice President of the China Council for the Promot...The China Expo Forum for International Cooperation(CEFCO)2026 was held in Wuhan,Hubei Province,China,on January 22.The opening ceremony was attended by Li Qing Shuang,Vice President of the China Council for the Promotion of International Trade(CCPIT);Zhu Yuji,Deputy Secretary of the Hubei Provincial Committee of the Communist Party of China;Sheng Yue Chun,Member of the Standing Committee of the Hubei Provincial Committee of the Communist Party of China and Secretary of the Wuhan Municipal Committee;Punita Bhansal,President of the Global Association of the Exhibition Industry(UFI);Marsha Flanagan,President and CEO of the International Association of Exhibitions and Events(IAEE);Vincent Polito,CEO of the Society of Independent Show Organizers(SISO);and Leonie Ashford,Board Member of the International Congress and Convention Association(ICCA).展开更多
1.Introduction Mobile communications have catalyzed a new era of informa-tion technology revolution,significantly broadening and deepen-ing human-to-human,human-to-machine,and machine-to-machine connections.With their...1.Introduction Mobile communications have catalyzed a new era of informa-tion technology revolution,significantly broadening and deepen-ing human-to-human,human-to-machine,and machine-to-machine connections.With their incredible speed of development and wide-reaching impact,mobile communications serve as the cornerstone of the Internet of Everything,profoundly reshaping human cognitive abilities and ways of thinking.Furthermore,mobile communications are altering the patterns of production and life,driving leaps in productivity quality,and strongly promot-ing innovation within human civilization.展开更多
A buckling-restrained steel plate shear wall(BRSPSW)structure with butterfly-shaped links on the lateral sides is introduced to improve the cooperative perfor-mance between the BRSPSW and the boundary frames.A one-spa...A buckling-restrained steel plate shear wall(BRSPSW)structure with butterfly-shaped links on the lateral sides is introduced to improve the cooperative perfor-mance between the BRSPSW and the boundary frames.A one-span two-story concrete-filled steel tube(CFT)column frame specimen equipped with lateral-side butterfly-shaped linked BRSPSWs(LBL-BRSPSWs)is evaluated under low-cycle reversed loading.A finite element(FE)model is developed and validated based on the test results.This FE model accurately simulates the failure modes and load-dis-placement curves.Parametric analyses are conducted on the butterfly-shaped links.The results show that the interactions between the CFT column frame and LBL-BRSPSWs are sig-nificantly influenced by the width ratio of the butterfly-shaped links,while the taper ratio and aspect ratio have relatively minor influences.Compared with traditional steel shear walls with four-sided connections,LBL-BRSPSWs reduce the additional axial forces and bending moments in the frame columns by 28%to 73%and 17%to 87%,respectively,with only a 9%to 30%decrease in the lateral resistance.The experimental and parametric analysis results indicate that setting butterfly-shaped links on the lateral sides of BRSPSWs can significantly enhance their cooperative performance with the boundary frame.The butterfly-shaped link width ratio has a linear relationship with the lateral-resistance performance of the specimens and the additional internal forces in the frame columns.To ensure that LBL-BRSPSW fails prior to the column frames,the link width ratio should be optimized.展开更多
Mechanically interlocked molecules (MIMs) have unique properties with broad applications, yet constructing both knotted and linked topologies from the same ligand remains challenging due to their distinct geometric de...Mechanically interlocked molecules (MIMs) have unique properties with broad applications, yet constructing both knotted and linked topologies from the same ligand remains challenging due to their distinct geometric demands. To address this, we design and synthesize a conformationally adaptive ligand 4,7-bis(3-(pyridin-4-yl) phenyl) benzo[c][1,2,5]thiadiazole (L1) with a tunable torsional angle θ of N1C1C2N2 ranging from 7.5° to 108.9°. Utilizing coordination-driven self-assembly at ambient temperature, L1 selectively assembles with binuclear half-sandwich units RhB1, RhB2, RhB3, and RhB4 featuring Cp*^(Rh^(Ⅲ)) (Cp* = η^(5)-pentam-ethylcyclopentadienyl) into distinct topologies: Solomon links Rh-1, trefoil knots Rh-2, molecular tweezers Rh 3, and Rh-4, respectively. Crucially, the self-adaptability of ligand L1 directs topology formation through pro-gramming different combination of noncovalent interactions (π-x stacking, CH..π interaction, and lone pair-π interaction), thus navigating divergent assembly pathways by conformational switching, as evidenced by X-ray crystallography analysis, independent gradient model (IGM) analysis, detailed nuclear magnetic resonance (NMR) spectroscopy and electrospray ionization time-of-flight/mass spectrometry (ESI-TOF/MS). This strategy can also be extended to construct Cp*^(Irl^(Ⅲ)) analogs (Solomon links Ir-1, trefoil knots Ir-2, molecular tweezers Ir-3 and Ir-4), demonstrating metal-independent control and achieving intricate topologies in a high yield.展开更多
This article presents the design of a microfabricated bio-inspired flapping-wing Nnano Aaerial Vvehicle(NAV),driven by an electromagnetic system.Our approach is based on artificial wings composed of rigid bodies conne...This article presents the design of a microfabricated bio-inspired flapping-wing Nnano Aaerial Vvehicle(NAV),driven by an electromagnetic system.Our approach is based on artificial wings composed of rigid bodies connected by compliant links,which optimise aerodynamic forces though replicating the complex wing kinematics of insects.The originality of this article lies in a new design methodology based on a triple equivalence between a 3D model,a multibody model,and a mass/spring model(0D)which reduces the number of parameters in the problem.This approach facilitates NAV optimisation by using only the mass/spring model,thereby simplifying the design process while maintaining high accuracy.Two wing geometries are studied and optimised in this article to produce large-amplitude wing motions(approximately 40^\circ),and enabling flapping and twisting motion in quadrature.The results are validated thanks to experimental measurements for the large amplitude and through finite element simulations for the combined motion,confirming the effectiveness of this strategy for a NAV weighing less than 40 mg with a wingspan of under 3 cm.展开更多
The Tian Qin space-borne gravitational wave detector will orbit at an altitude of1.0×10^(5)km with an arm length of 1.7×10^(5)km,structured in an equilateral triangular satellite formation.The Tian Qin proje...The Tian Qin space-borne gravitational wave detector will orbit at an altitude of1.0×10^(5)km with an arm length of 1.7×10^(5)km,structured in an equilateral triangular satellite formation.The Tian Qin project delineates detailed requirements for orbit determination during both the launch phase and subsequent scientific experimentation.This paper pioneers the investigation of Precise Orbit Determination(POD)for Tian Qin utilizing the third generation of Bei Dou global navigation satellite system(BDS-3)Inter-Satellite Link(ISL)through simulation.By analyzing the visibility,the feasibility of using BDS-3 ISLs for Tian Qin POD is explored.Furthermore,a refined Solar Radiation Pressure(SRP)model is developed,and the POD accuracy of Tian Qin is assessed,considering factors such as arc length,ranging intervals,and error sources.The results indicate the following:(A)Visibility between Tian Qin and BDS-3 satellites is intermittent,with an average of 10.6 BDS-3 satellites visible to Tian Qin,and the average Root Mean Square(RMS)-value of Position Dilution of Precision(PDOP)for Tian Qin is 48.13.(B)POD accuracy improves with shorter ranging intervals.(C)The error in ephemeris is the dominant factor affecting the POD accuracy.(D)The establishment of three links between Tian Qin and the BDS-3 satellites satisfies the POD requirements of Tian Qin.With a ranging interval of 600 s and over a 7-day arc,the average three-Dimensional(3D)position accuracy of the three Tian Qin satellites is 1.35 m,while the 3D velocity accuracy is 0.08 mm/s.展开更多
In order to suppress vibration in flexible manipulators, a new type of manipulator mechanism with controllable local degrees of freedom is proposed. This mechanism consists of a main chain and some branch links. The m...In order to suppress vibration in flexible manipulators, a new type of manipulator mechanism with controllable local degrees of freedom is proposed. This mechanism consists of a main chain and some branch links. The main chain is of a flexible open-chain configuration with an end-effector installed at its tip, and the rigid branch links are able to perform active movements. It is proved by kinematics and dynamic analysis that, the branch links bear no direct kinematic relation to the main chain, but their independent motions can strongly affect the dynamic behavior and performance of the flexible manipulator. Then comes a new idea of suppressing vibration, in which independent motions of the branch links are used to suppress the undesired vibration of the flexible main chain through dynamic coupling. On this basis, an optimal method for reducing vibration of flexible manipulators is proposed. Finally, the effectiveness of this method is verified by numerical simulations.展开更多
In response to the demand for seismic-resilient structures,various innovative solutions have emerged to reduce local damage and residual deformations,facilitating repair operations in the aftermath of high-intensity e...In response to the demand for seismic-resilient structures,various innovative solutions have emerged to reduce local damage and residual deformations,facilitating repair operations in the aftermath of high-intensity earth-quakes.This paper examines the seismic performance of a steel-concrete hybrid wall system equipped with a selfcentering solution to mitigate earthquake-induced residual deformations.The considered hybrid system includes a Reinforced Concrete(RC)shear wall with two steel side columns connected by coupling steel beams.In this study,a novel type of coupling beams featuring a friction-damped self-centering system is implemented.The system is referred to as Self-Centering Hybrid Single-Pier Coupled Wall(SC-SP-HCW)and aims to minimize damage and residual deformations after earthquakes,which in turn facilitates repairs and enhances seismic resilience.Unlike conventional self-centering coupling beams with post-tensioned tendons,the self-centering configuration in this system does not rely on a gap-opening mechanism at the wall-beam connection interface,eliminating frame expansion effects.The proposed self-centering devices can also be implemented as preassembled links,which facilitates installation and reduces uncertainties associated with the on-site posttensioning procedure.The seismic performance of SC-SP-HCWs is investigated through nonlinear static and incremental dynamic analyses on case study SC-SP-HCWs designed as the lateral load-resisting systems of an eight-story building.The seismic response of the case study SC-SP-HCWs is investigated,considering both local and global engineering demand parameters(EDPs).The results demonstrate the ability of the SC-SP-HCWs to significantly reduce earthquake-induced residual deformations without exacerbating damage to structural ele-ments typically observed in conventional coupled walls.展开更多
Community detection is a fundamental problem in network analysis for identifying densely connected node clusters,with successful applications in diverse fields like social networks,recommendation systems,biology,and c...Community detection is a fundamental problem in network analysis for identifying densely connected node clusters,with successful applications in diverse fields like social networks,recommendation systems,biology,and cyberattack detection.Overlapping community detection refers to the case of a node belonging to multiple communities simultaneously,which is a much more meaningful and challenging task.Graph representation learning with Evolutionary Computation has been studied well in overlapping community detection to deal with complex network structures and characteristics.However,most of them focus on searching the entire solution space,which can be inefficient and lead to inadequate results.To overcome the problem,a structural feature node extraction method is first proposed that can effectively map a network into a structural embedding space.Thus,nodes within the network are classified into hierarchical levels based on their structural feature strength,and only nodes with relatively high strength are considered in subsequent search steps to reduce the search space.Then,a maximal-clique representation method is employed on the given vertex set to identify overlapping nodes.A hybrid clique-based multi-objective evolutionary algorithmwith decomposition method is designed to address cliques and the remaining unexplored nodes separately.The number of communities generated with this allocation method is closer to the actual partition count with high division quality.Experimental results on nine usually used real-world networks,five synthetic networks,and two large-scale networks demonstrate the effectiveness of the proposed methodology in terms of community quality and algorithmic efficiency,compared to traditional,MOEA-based,and graph embedding-based community detection algorithms.展开更多
The Routing Protocol for Low-power and Lossy Networks(RPL)is widely used in Internet of Things(IoT)systems,where devices usually have very limited resources.However,RPL still faces several problems,such as high energy...The Routing Protocol for Low-power and Lossy Networks(RPL)is widely used in Internet of Things(IoT)systems,where devices usually have very limited resources.However,RPL still faces several problems,such as high energy usage,unstable links,and inefficient routing decisions,which reduce the overall network performance and lifetime.In this work,we introduce TABURPL,an improved routing method that applies Tabu Search(TS)to optimize the parent selection process.The method uses a combined cost function that considers Residual Energy,Transmission Energy,Distance to the Sink,Hop Count,Expected Transmission Count(ETX),and Link Stability Rate(LSR).Simulation results show that TABURPL improves link stability,lowers energy consumption,and increases the packet delivery ratio compared with standard RPL and other existing approaches.These results indicate that Tabu Search can handle the complex trade-offs in IoT routing and can provide a more reliable solution for extending the network lifetime.展开更多
As an important resource in data link,time slots should be strategically allocated to enhance transmission efficiency and resist eavesdropping,especially considering the tremendous increase in the number of nodes and ...As an important resource in data link,time slots should be strategically allocated to enhance transmission efficiency and resist eavesdropping,especially considering the tremendous increase in the number of nodes and diverse communication needs.It is crucial to design control sequences with robust randomness and conflict-freeness to properly address differentiated access control in data link.In this paper,we propose a hierarchical access control scheme based on control sequences to achieve high utilization of time slots and differentiated access control.A theoretical bound of the hierarchical control sequence set is derived to characterize the constraints on the parameters of the sequence set.Moreover,two classes of optimal hierarchical control sequence sets satisfying the theoretical bound are constructed,both of which enable the scheme to achieve maximum utilization of time slots.Compared with the fixed time slot allocation scheme,our scheme reduces the symbol error rate by up to 9%,which indicates a significant improvement in anti-interference and eavesdropping capabilities.展开更多
Temporal knowledge graph completion(TKGC),which merges temporal information into traditional static knowledge graph completion(SKGC),has garnered increasing attention recently.Among numerous emerging approaches,transl...Temporal knowledge graph completion(TKGC),which merges temporal information into traditional static knowledge graph completion(SKGC),has garnered increasing attention recently.Among numerous emerging approaches,translation-based embedding models constitute a prominent approach in TKGC research.However,existing translation-based methods typically incorporate timestamps into entities or relations,rather than utilizing them independently.This practice fails to fully exploit the rich semantics inherent in temporal information,thereby weakening the expressive capability of models.To address this limitation,we propose embedding timestamps,like entities and relations,in one or more dedicated semantic spaces.After projecting all embeddings into a shared space,we use the relation-timestamp pair instead of the conventional relation embedding as the translation vector between head and tail entities.Our method elevates timestamps to the same representational significance as entities and relations.Based on this strategy,we introduce two novel translation-based embedding models:TE-TransR and TE-TransT.With the independent representation of timestamps,our method not only enhances capabilities in link prediction but also facilitates a relatively underexplored task,namely time prediction.To further bolster the precision and reliability of time prediction,we introduce a granular,time unit-based timestamp setting and a relation-specific evaluation protocol.Extensive experiments demonstrate that our models achieve strong performance on link prediction benchmarks,with TE-TransR outperforming existing baselines in the time prediction task.展开更多
Cascading failures pose a serious threat to the survivability of underwater unmanned swarm networks(UUSNs),significantly limiting their service ability in collaborative missions such as military reconnaissance and env...Cascading failures pose a serious threat to the survivability of underwater unmanned swarm networks(UUSNs),significantly limiting their service ability in collaborative missions such as military reconnaissance and environmental monitoring.Existing failure models primarily focus on power grids and traffic systems,and don't address the unique challenges of weak-communication UUSNs.In UUSNs,cascading failure present a complex and dynamic process driven by the coupling of unstable acoustic channels,passive node drift,adversarial attacks,and network heterogeneity.To address these challenges,a directed weighted graph model of UUSNs is first developed,in which node positions are updated according to ocean-current-driven drift and link weights reflect the probability of successful acoustic transmission.Building on this UUSNs graph model,a cascading failure model is proposed that integrates a normal-failure-recovery state-cycle mechanism,multiple attack strategies,and routingbased load redistribution.Finally,under a five-level connectivity UUSNs scheme,simulations are conducted to analyze how dynamic topology,network load,node recovery delay,and attack modes jointly affect network survivability.The main findings are:(1)moderate node drift can improve survivability by activating weak links;(2)based-energy routing(BER)outperform based-depth routing(BDR)in harsh conditions;(3)node self-recovery time is critical to network survivability;(4)traditional degree-based critical node metrics are inadequate for weak-communication UUSNs.These results provide a theoretical foundation for designing robust survivability mechanisms in weak-communication UUSNs.展开更多
As a classical model of statistical physics, the percolation theory provides a powerful approach to analyze the network structure and dynamics. Recently, to model the relations among interacting agents beyond the conn...As a classical model of statistical physics, the percolation theory provides a powerful approach to analyze the network structure and dynamics. Recently, to model the relations among interacting agents beyond the connection of the networked system, the concept of dependence link is proposed to represent the dependence relationship of agents. These studies suggest that the percolation properties of these networks differ greatly from those of the ordinary networks. In particular, unlike the well known continuous transition on the ordinary networks, the percolation transitions on these networks are discontinuous. Moreover, these networks are more fragile for a broader degree distribution, which is opposite to the famous results for the ordinary networks. In this article, we give a summary of the theoretical approaches to study the percolation process on networks with inter- and inner-dependence links, and review the recent advances in this field, focusing on the topology and robustness of such networks.展开更多
Under the conditions of joint torque output dead-zone and external disturbance,the trajectory tracking and vibration suppression for a free-floating space robot(FFSR)system with elastic base and flexible links were di...Under the conditions of joint torque output dead-zone and external disturbance,the trajectory tracking and vibration suppression for a free-floating space robot(FFSR)system with elastic base and flexible links were discussed.First,using the Lagrange equation of the second kind,the dynamic model of the system was derived.Second,utilizing singular perturbation theory,a slow subsystem describing the rigid motion and a fast subsystem corresponding to flexible vibration were obtained.For the slow subsystem,when the width of deadzone is uncertain,a dead-zone pre-compensator was designed to eliminate the impact of joint torque output dead-zone,and an integral sliding mode neural network control was proposed.The integral sliding mode term can reduce the steady state error.For the fast subsystem,an optimal linear quadratic regulator(LQR)controller was adopted to damp out the vibration of the flexible links and elastic base simultaneously.Finally,computer simulations show the effectiveness of the compound control method.展开更多
Cooperative utilization of multidimensional resources including cache, power and spectrum in satellite-terrestrial integrated networks(STINs) can provide a feasible approach for massive streaming media content deliver...Cooperative utilization of multidimensional resources including cache, power and spectrum in satellite-terrestrial integrated networks(STINs) can provide a feasible approach for massive streaming media content delivery over the seamless global coverage area. However, the on-board supportable resources of a single satellite are extremely limited and lack of interaction with others. In this paper, we design a network model with two-layered cache deployment, i.e., satellite layer and ground base station layer, and two types of sharing links, i.e., terrestrial-satellite sharing(TSS) links and inter-satellite sharing(ISS) links, to enhance the capability of cooperative delivery over STINs. Thus, we use rateless codes for the content divided-packet transmission, and derive the total energy efficiency(EE) in the whole transmission procedure, which is defined as the ratio of traffic offloading and energy consumption. We formulate two optimization problems about maximizing EE in different sharing scenarios(only TSS and TSS-ISS),and propose two optimized algorithms to obtain the optimal content placement matrixes, respectively.Simulation results demonstrate that, enabling sharing links with optimized cache placement have more than 2 times improvement of EE performance than other traditional placement schemes. Particularly, TSS-ISS schemes have the higher EE performance than only TSS schemes under the conditions of enough number of satellites and smaller inter-satellite distances.展开更多
The object of study is about dynamic modeling and control for a 2degree-of-freedom (DOF) planar parallel mechanism (PM) with flexible links. The kinematic anddynamic equations are established according to the characte...The object of study is about dynamic modeling and control for a 2degree-of-freedom (DOF) planar parallel mechanism (PM) with flexible links. The kinematic anddynamic equations are established according to the characteristics of mixed rigid and flexiblestructure. By using the singular perturbation approach (SPA), the model of the mechanism can beseparated into slow and fast subsystems. Based on the feedback linearization theory and inputshaping technique, the large scale rigid motion controller and the flexible link vibrationcontroller can be designed separately to achieve fast and accurate positioning of the PM.展开更多
The chain/wire rope/chain combination is a common choice for mooring offshore floating platforms. However, data of the drag coefficients of chain links are rather limited, resulting in uncertainties with the calculati...The chain/wire rope/chain combination is a common choice for mooring offshore floating platforms. However, data of the drag coefficients of chain links are rather limited, resulting in uncertainties with the calculations of the drag force, and hence the damping of the mooring system. In this paper, the importance of the selection of the drag coefficient is first investigated. The computational fluid dynamics(CFD) method is then used to determine the drag coefficients of a studless chain under steady flows. Numerical model validation is first completed by simulating a smooth circular cylinder under steady flows. In particular, the performance of different turbulence models is assessed through the comparisons between the calculations and the experimental results. The large eddy simulation(LES) model is finally selected for the simulation of steady flows past a chain. The effects of the Reynolds number on the drag coefficient of a stud-less chain is also studied. The results show that the calculated drag coefficients of a stud-less chain are fairly consistent with the available experimental data.展开更多
An optimization model is proposed to examine the choice of sharing or not sharing the product link for manufacturing firms with owned social media by considering the role of fan effects.The equilibrium marketing effor...An optimization model is proposed to examine the choice of sharing or not sharing the product link for manufacturing firms with owned social media by considering the role of fan effects.The equilibrium marketing effort level and firm profit in both cases are compared.The results show that the firm chooses to share(not share)the product link when the social platform commission rate is low(high).Moreover,the likelihood of sharing the product link increases as the fan effect weakens and the perceived conversion cost strengthens.Interestingly,the marketing effort level increases with the product price,but firm profit does not always follow.Additionally,as the fan effect and fan count grow,so does the firm s profit.Furthermore,when the firm shares the product link,the level of marketing effort and firm profit decrease with the commission rate.Conversely,when the firm does not share the product link,those aforementioned factors increase as the perceived conversion cost declines.These results thus suggest that firms should enhance the influence of owned social media to attract more high-quality fans,and social platforms should optimize the product link functionality.展开更多
文摘The China Expo Forum for International Cooperation(CEFCO)2026 was held in Wuhan,Hubei Province,China,on January 22.The opening ceremony was attended by Li Qing Shuang,Vice President of the China Council for the Promotion of International Trade(CCPIT);Zhu Yuji,Deputy Secretary of the Hubei Provincial Committee of the Communist Party of China;Sheng Yue Chun,Member of the Standing Committee of the Hubei Provincial Committee of the Communist Party of China and Secretary of the Wuhan Municipal Committee;Punita Bhansal,President of the Global Association of the Exhibition Industry(UFI);Marsha Flanagan,President and CEO of the International Association of Exhibitions and Events(IAEE);Vincent Polito,CEO of the Society of Independent Show Organizers(SISO);and Leonie Ashford,Board Member of the International Congress and Convention Association(ICCA).
基金supported by the National Key Research and Develop-ment Program of China(2019YFB1803400).
文摘1.Introduction Mobile communications have catalyzed a new era of informa-tion technology revolution,significantly broadening and deepen-ing human-to-human,human-to-machine,and machine-to-machine connections.With their incredible speed of development and wide-reaching impact,mobile communications serve as the cornerstone of the Internet of Everything,profoundly reshaping human cognitive abilities and ways of thinking.Furthermore,mobile communications are altering the patterns of production and life,driving leaps in productivity quality,and strongly promot-ing innovation within human civilization.
基金The National Key Research and Development Program of China(No.2023YFC3805005)Shanghai Municipal Science and Technology Commission Research Program(No.22DZ1201404).
文摘A buckling-restrained steel plate shear wall(BRSPSW)structure with butterfly-shaped links on the lateral sides is introduced to improve the cooperative perfor-mance between the BRSPSW and the boundary frames.A one-span two-story concrete-filled steel tube(CFT)column frame specimen equipped with lateral-side butterfly-shaped linked BRSPSWs(LBL-BRSPSWs)is evaluated under low-cycle reversed loading.A finite element(FE)model is developed and validated based on the test results.This FE model accurately simulates the failure modes and load-dis-placement curves.Parametric analyses are conducted on the butterfly-shaped links.The results show that the interactions between the CFT column frame and LBL-BRSPSWs are sig-nificantly influenced by the width ratio of the butterfly-shaped links,while the taper ratio and aspect ratio have relatively minor influences.Compared with traditional steel shear walls with four-sided connections,LBL-BRSPSWs reduce the additional axial forces and bending moments in the frame columns by 28%to 73%and 17%to 87%,respectively,with only a 9%to 30%decrease in the lateral resistance.The experimental and parametric analysis results indicate that setting butterfly-shaped links on the lateral sides of BRSPSWs can significantly enhance their cooperative performance with the boundary frame.The butterfly-shaped link width ratio has a linear relationship with the lateral-resistance performance of the specimens and the additional internal forces in the frame columns.To ensure that LBL-BRSPSW fails prior to the column frames,the link width ratio should be optimized.
基金Department of Chemistry,Fudan Uni-versity,the National Natural Science Foundation of China(22031003,21720102004)the Shanghai Science Technology Committee(19DZ227010O)the Alexander von Humboldt Foundation for a Humboldt Research Award.
文摘Mechanically interlocked molecules (MIMs) have unique properties with broad applications, yet constructing both knotted and linked topologies from the same ligand remains challenging due to their distinct geometric demands. To address this, we design and synthesize a conformationally adaptive ligand 4,7-bis(3-(pyridin-4-yl) phenyl) benzo[c][1,2,5]thiadiazole (L1) with a tunable torsional angle θ of N1C1C2N2 ranging from 7.5° to 108.9°. Utilizing coordination-driven self-assembly at ambient temperature, L1 selectively assembles with binuclear half-sandwich units RhB1, RhB2, RhB3, and RhB4 featuring Cp*^(Rh^(Ⅲ)) (Cp* = η^(5)-pentam-ethylcyclopentadienyl) into distinct topologies: Solomon links Rh-1, trefoil knots Rh-2, molecular tweezers Rh 3, and Rh-4, respectively. Crucially, the self-adaptability of ligand L1 directs topology formation through pro-gramming different combination of noncovalent interactions (π-x stacking, CH..π interaction, and lone pair-π interaction), thus navigating divergent assembly pathways by conformational switching, as evidenced by X-ray crystallography analysis, independent gradient model (IGM) analysis, detailed nuclear magnetic resonance (NMR) spectroscopy and electrospray ionization time-of-flight/mass spectrometry (ESI-TOF/MS). This strategy can also be extended to construct Cp*^(Irl^(Ⅲ)) analogs (Solomon links Ir-1, trefoil knots Ir-2, molecular tweezers Ir-3 and Ir-4), demonstrating metal-independent control and achieving intricate topologies in a high yield.
基金supported by ANR-ASTRID NANOFLY(ANR-19-ASTR-0023)and French AID(Defense Innovation Agency).
文摘This article presents the design of a microfabricated bio-inspired flapping-wing Nnano Aaerial Vvehicle(NAV),driven by an electromagnetic system.Our approach is based on artificial wings composed of rigid bodies connected by compliant links,which optimise aerodynamic forces though replicating the complex wing kinematics of insects.The originality of this article lies in a new design methodology based on a triple equivalence between a 3D model,a multibody model,and a mass/spring model(0D)which reduces the number of parameters in the problem.This approach facilitates NAV optimisation by using only the mass/spring model,thereby simplifying the design process while maintaining high accuracy.Two wing geometries are studied and optimised in this article to produce large-amplitude wing motions(approximately 40^\circ),and enabling flapping and twisting motion in quadrature.The results are validated thanks to experimental measurements for the large amplitude and through finite element simulations for the combined motion,confirming the effectiveness of this strategy for a NAV weighing less than 40 mg with a wingspan of under 3 cm.
基金co-supported by the Guangdong Major Project of Basic and Applied Basic Research,China(No.2019B030302001)the Guangdong Basic and Applied Basic Research Foundation,China(No.2022A1515110236)the Fundamental Research Funds for the Central Universities,Sun Yat-Sen University,China(No.23xkjc001)。
文摘The Tian Qin space-borne gravitational wave detector will orbit at an altitude of1.0×10^(5)km with an arm length of 1.7×10^(5)km,structured in an equilateral triangular satellite formation.The Tian Qin project delineates detailed requirements for orbit determination during both the launch phase and subsequent scientific experimentation.This paper pioneers the investigation of Precise Orbit Determination(POD)for Tian Qin utilizing the third generation of Bei Dou global navigation satellite system(BDS-3)Inter-Satellite Link(ISL)through simulation.By analyzing the visibility,the feasibility of using BDS-3 ISLs for Tian Qin POD is explored.Furthermore,a refined Solar Radiation Pressure(SRP)model is developed,and the POD accuracy of Tian Qin is assessed,considering factors such as arc length,ranging intervals,and error sources.The results indicate the following:(A)Visibility between Tian Qin and BDS-3 satellites is intermittent,with an average of 10.6 BDS-3 satellites visible to Tian Qin,and the average Root Mean Square(RMS)-value of Position Dilution of Precision(PDOP)for Tian Qin is 48.13.(B)POD accuracy improves with shorter ranging intervals.(C)The error in ephemeris is the dominant factor affecting the POD accuracy.(D)The establishment of three links between Tian Qin and the BDS-3 satellites satisfies the POD requirements of Tian Qin.With a ranging interval of 600 s and over a 7-day arc,the average three-Dimensional(3D)position accuracy of the three Tian Qin satellites is 1.35 m,while the 3D velocity accuracy is 0.08 mm/s.
基金Ministry of Education Important Research Project of Scienceand Technology of China(307005)National Hi-Tech Research and Development Program of China(SQ2007AA04Z231266)
文摘In order to suppress vibration in flexible manipulators, a new type of manipulator mechanism with controllable local degrees of freedom is proposed. This mechanism consists of a main chain and some branch links. The main chain is of a flexible open-chain configuration with an end-effector installed at its tip, and the rigid branch links are able to perform active movements. It is proved by kinematics and dynamic analysis that, the branch links bear no direct kinematic relation to the main chain, but their independent motions can strongly affect the dynamic behavior and performance of the flexible manipulator. Then comes a new idea of suppressing vibration, in which independent motions of the branch links are used to suppress the undesired vibration of the flexible main chain through dynamic coupling. On this basis, an optimal method for reducing vibration of flexible manipulators is proposed. Finally, the effectiveness of this method is verified by numerical simulations.
基金supported by the European Union’s Horizon 2020 research and innovation program under grant agreement No.101027745(Marie Sklodowska-Curie Research Grant Scheme H2020-MSCA-IF-2020:Self-Centering Earthquake-Resilient Hybrid Steel-Concrete Shear Walls with Rocking Beams-SC-HYBWalls)the support from the Royal Society-Interna-tional Exchange programme under the grant agreement IES\R3\213175.
文摘In response to the demand for seismic-resilient structures,various innovative solutions have emerged to reduce local damage and residual deformations,facilitating repair operations in the aftermath of high-intensity earth-quakes.This paper examines the seismic performance of a steel-concrete hybrid wall system equipped with a selfcentering solution to mitigate earthquake-induced residual deformations.The considered hybrid system includes a Reinforced Concrete(RC)shear wall with two steel side columns connected by coupling steel beams.In this study,a novel type of coupling beams featuring a friction-damped self-centering system is implemented.The system is referred to as Self-Centering Hybrid Single-Pier Coupled Wall(SC-SP-HCW)and aims to minimize damage and residual deformations after earthquakes,which in turn facilitates repairs and enhances seismic resilience.Unlike conventional self-centering coupling beams with post-tensioned tendons,the self-centering configuration in this system does not rely on a gap-opening mechanism at the wall-beam connection interface,eliminating frame expansion effects.The proposed self-centering devices can also be implemented as preassembled links,which facilitates installation and reduces uncertainties associated with the on-site posttensioning procedure.The seismic performance of SC-SP-HCWs is investigated through nonlinear static and incremental dynamic analyses on case study SC-SP-HCWs designed as the lateral load-resisting systems of an eight-story building.The seismic response of the case study SC-SP-HCWs is investigated,considering both local and global engineering demand parameters(EDPs).The results demonstrate the ability of the SC-SP-HCWs to significantly reduce earthquake-induced residual deformations without exacerbating damage to structural ele-ments typically observed in conventional coupled walls.
基金supported in part by the National Natural Science Foundation of China under Grants 62473176,62073155,62002137,62106088,and 62206113National Key Laboratory of Ship Structural Safety underGrant 450324300the Postgraduate Research&Practice Innovation Programof Jiangsu Province under Grant KYCX24_2642.
文摘Community detection is a fundamental problem in network analysis for identifying densely connected node clusters,with successful applications in diverse fields like social networks,recommendation systems,biology,and cyberattack detection.Overlapping community detection refers to the case of a node belonging to multiple communities simultaneously,which is a much more meaningful and challenging task.Graph representation learning with Evolutionary Computation has been studied well in overlapping community detection to deal with complex network structures and characteristics.However,most of them focus on searching the entire solution space,which can be inefficient and lead to inadequate results.To overcome the problem,a structural feature node extraction method is first proposed that can effectively map a network into a structural embedding space.Thus,nodes within the network are classified into hierarchical levels based on their structural feature strength,and only nodes with relatively high strength are considered in subsequent search steps to reduce the search space.Then,a maximal-clique representation method is employed on the given vertex set to identify overlapping nodes.A hybrid clique-based multi-objective evolutionary algorithmwith decomposition method is designed to address cliques and the remaining unexplored nodes separately.The number of communities generated with this allocation method is closer to the actual partition count with high division quality.Experimental results on nine usually used real-world networks,five synthetic networks,and two large-scale networks demonstrate the effectiveness of the proposed methodology in terms of community quality and algorithmic efficiency,compared to traditional,MOEA-based,and graph embedding-based community detection algorithms.
文摘The Routing Protocol for Low-power and Lossy Networks(RPL)is widely used in Internet of Things(IoT)systems,where devices usually have very limited resources.However,RPL still faces several problems,such as high energy usage,unstable links,and inefficient routing decisions,which reduce the overall network performance and lifetime.In this work,we introduce TABURPL,an improved routing method that applies Tabu Search(TS)to optimize the parent selection process.The method uses a combined cost function that considers Residual Energy,Transmission Energy,Distance to the Sink,Hop Count,Expected Transmission Count(ETX),and Link Stability Rate(LSR).Simulation results show that TABURPL improves link stability,lowers energy consumption,and increases the packet delivery ratio compared with standard RPL and other existing approaches.These results indicate that Tabu Search can handle the complex trade-offs in IoT routing and can provide a more reliable solution for extending the network lifetime.
基金supported by the National Science Foundation of China(No.62171387)the Science and Technology Program of Sichuan Province(No.2024NSFSC0468)the China Postdoctoral Science Foundation(No.2019M663475).
文摘As an important resource in data link,time slots should be strategically allocated to enhance transmission efficiency and resist eavesdropping,especially considering the tremendous increase in the number of nodes and diverse communication needs.It is crucial to design control sequences with robust randomness and conflict-freeness to properly address differentiated access control in data link.In this paper,we propose a hierarchical access control scheme based on control sequences to achieve high utilization of time slots and differentiated access control.A theoretical bound of the hierarchical control sequence set is derived to characterize the constraints on the parameters of the sequence set.Moreover,two classes of optimal hierarchical control sequence sets satisfying the theoretical bound are constructed,both of which enable the scheme to achieve maximum utilization of time slots.Compared with the fixed time slot allocation scheme,our scheme reduces the symbol error rate by up to 9%,which indicates a significant improvement in anti-interference and eavesdropping capabilities.
基金supported by the National Natural Science Foundation of China under Grant No.72293575.
文摘Temporal knowledge graph completion(TKGC),which merges temporal information into traditional static knowledge graph completion(SKGC),has garnered increasing attention recently.Among numerous emerging approaches,translation-based embedding models constitute a prominent approach in TKGC research.However,existing translation-based methods typically incorporate timestamps into entities or relations,rather than utilizing them independently.This practice fails to fully exploit the rich semantics inherent in temporal information,thereby weakening the expressive capability of models.To address this limitation,we propose embedding timestamps,like entities and relations,in one or more dedicated semantic spaces.After projecting all embeddings into a shared space,we use the relation-timestamp pair instead of the conventional relation embedding as the translation vector between head and tail entities.Our method elevates timestamps to the same representational significance as entities and relations.Based on this strategy,we introduce two novel translation-based embedding models:TE-TransR and TE-TransT.With the independent representation of timestamps,our method not only enhances capabilities in link prediction but also facilitates a relatively underexplored task,namely time prediction.To further bolster the precision and reliability of time prediction,we introduce a granular,time unit-based timestamp setting and a relation-specific evaluation protocol.Extensive experiments demonstrate that our models achieve strong performance on link prediction benchmarks,with TE-TransR outperforming existing baselines in the time prediction task.
基金supported in part by the National Natural Science Foundation of China(Key Program)under Grant No.62031021。
文摘Cascading failures pose a serious threat to the survivability of underwater unmanned swarm networks(UUSNs),significantly limiting their service ability in collaborative missions such as military reconnaissance and environmental monitoring.Existing failure models primarily focus on power grids and traffic systems,and don't address the unique challenges of weak-communication UUSNs.In UUSNs,cascading failure present a complex and dynamic process driven by the coupling of unstable acoustic channels,passive node drift,adversarial attacks,and network heterogeneity.To address these challenges,a directed weighted graph model of UUSNs is first developed,in which node positions are updated according to ocean-current-driven drift and link weights reflect the probability of successful acoustic transmission.Building on this UUSNs graph model,a cascading failure model is proposed that integrates a normal-failure-recovery state-cycle mechanism,multiple attack strategies,and routingbased load redistribution.Finally,under a five-level connectivity UUSNs scheme,simulations are conducted to analyze how dynamic topology,network load,node recovery delay,and attack modes jointly affect network survivability.The main findings are:(1)moderate node drift can improve survivability by activating weak links;(2)based-energy routing(BER)outperform based-depth routing(BDR)in harsh conditions;(3)node self-recovery time is critical to network survivability;(4)traditional degree-based critical node metrics are inadequate for weak-communication UUSNs.These results provide a theoretical foundation for designing robust survivability mechanisms in weak-communication UUSNs.
基金supported by the National Natural Science Foundation of China(Grant Nos.11275186 and 91024026)
文摘As a classical model of statistical physics, the percolation theory provides a powerful approach to analyze the network structure and dynamics. Recently, to model the relations among interacting agents beyond the connection of the networked system, the concept of dependence link is proposed to represent the dependence relationship of agents. These studies suggest that the percolation properties of these networks differ greatly from those of the ordinary networks. In particular, unlike the well known continuous transition on the ordinary networks, the percolation transitions on these networks are discontinuous. Moreover, these networks are more fragile for a broader degree distribution, which is opposite to the famous results for the ordinary networks. In this article, we give a summary of the theoretical approaches to study the percolation process on networks with inter- and inner-dependence links, and review the recent advances in this field, focusing on the topology and robustness of such networks.
基金Supported by the National Natural Science Foundation of China(11372073,11072061)Industrial Robot Basic Component Technology Research and Development Platform,Fujian,China(2014H21010011)。
文摘Under the conditions of joint torque output dead-zone and external disturbance,the trajectory tracking and vibration suppression for a free-floating space robot(FFSR)system with elastic base and flexible links were discussed.First,using the Lagrange equation of the second kind,the dynamic model of the system was derived.Second,utilizing singular perturbation theory,a slow subsystem describing the rigid motion and a fast subsystem corresponding to flexible vibration were obtained.For the slow subsystem,when the width of deadzone is uncertain,a dead-zone pre-compensator was designed to eliminate the impact of joint torque output dead-zone,and an integral sliding mode neural network control was proposed.The integral sliding mode term can reduce the steady state error.For the fast subsystem,an optimal linear quadratic regulator(LQR)controller was adopted to damp out the vibration of the flexible links and elastic base simultaneously.Finally,computer simulations show the effectiveness of the compound control method.
基金supported by National Natural Sciences Foundation of China(No.62271165,62027802,61831008)the Guangdong Basic and Applied Basic Research Foundation(No.2023A1515030297,2021A1515011572)Shenzhen Science and Technology Program ZDSYS20210623091808025,Stable Support Plan Program GXWD20231129102638002.
文摘Cooperative utilization of multidimensional resources including cache, power and spectrum in satellite-terrestrial integrated networks(STINs) can provide a feasible approach for massive streaming media content delivery over the seamless global coverage area. However, the on-board supportable resources of a single satellite are extremely limited and lack of interaction with others. In this paper, we design a network model with two-layered cache deployment, i.e., satellite layer and ground base station layer, and two types of sharing links, i.e., terrestrial-satellite sharing(TSS) links and inter-satellite sharing(ISS) links, to enhance the capability of cooperative delivery over STINs. Thus, we use rateless codes for the content divided-packet transmission, and derive the total energy efficiency(EE) in the whole transmission procedure, which is defined as the ratio of traffic offloading and energy consumption. We formulate two optimization problems about maximizing EE in different sharing scenarios(only TSS and TSS-ISS),and propose two optimized algorithms to obtain the optimal content placement matrixes, respectively.Simulation results demonstrate that, enabling sharing links with optimized cache placement have more than 2 times improvement of EE performance than other traditional placement schemes. Particularly, TSS-ISS schemes have the higher EE performance than only TSS schemes under the conditions of enough number of satellites and smaller inter-satellite distances.
基金This project is supported by National Natural Science Foundation of China (No.50390064, No.50375099) Doctorate Foundation of Ministry of Education of China(No.20020248048).
文摘The object of study is about dynamic modeling and control for a 2degree-of-freedom (DOF) planar parallel mechanism (PM) with flexible links. The kinematic anddynamic equations are established according to the characteristics of mixed rigid and flexiblestructure. By using the singular perturbation approach (SPA), the model of the mechanism can beseparated into slow and fast subsystems. Based on the feedback linearization theory and inputshaping technique, the large scale rigid motion controller and the flexible link vibrationcontroller can be designed separately to achieve fast and accurate positioning of the PM.
基金financial support for the PhD study from GL-Nobel Denton based in London
文摘The chain/wire rope/chain combination is a common choice for mooring offshore floating platforms. However, data of the drag coefficients of chain links are rather limited, resulting in uncertainties with the calculations of the drag force, and hence the damping of the mooring system. In this paper, the importance of the selection of the drag coefficient is first investigated. The computational fluid dynamics(CFD) method is then used to determine the drag coefficients of a studless chain under steady flows. Numerical model validation is first completed by simulating a smooth circular cylinder under steady flows. In particular, the performance of different turbulence models is assessed through the comparisons between the calculations and the experimental results. The large eddy simulation(LES) model is finally selected for the simulation of steady flows past a chain. The effects of the Reynolds number on the drag coefficient of a stud-less chain is also studied. The results show that the calculated drag coefficients of a stud-less chain are fairly consistent with the available experimental data.
基金The National Natural Science Foundation of China(No.71871054)。
文摘An optimization model is proposed to examine the choice of sharing or not sharing the product link for manufacturing firms with owned social media by considering the role of fan effects.The equilibrium marketing effort level and firm profit in both cases are compared.The results show that the firm chooses to share(not share)the product link when the social platform commission rate is low(high).Moreover,the likelihood of sharing the product link increases as the fan effect weakens and the perceived conversion cost strengthens.Interestingly,the marketing effort level increases with the product price,but firm profit does not always follow.Additionally,as the fan effect and fan count grow,so does the firm s profit.Furthermore,when the firm shares the product link,the level of marketing effort and firm profit decrease with the commission rate.Conversely,when the firm does not share the product link,those aforementioned factors increase as the perceived conversion cost declines.These results thus suggest that firms should enhance the influence of owned social media to attract more high-quality fans,and social platforms should optimize the product link functionality.
