The Social Internet of Things(SIoT)integrates the Internet of Things(IoT)and social networks,taking into account the social attributes of objects and diversifying the relationship between humans and objects,which over...The Social Internet of Things(SIoT)integrates the Internet of Things(IoT)and social networks,taking into account the social attributes of objects and diversifying the relationship between humans and objects,which overcomes the limitations of the IoT’s focus on associations between objects.Artificial Intelligence(AI)technology is rapidly evolving.It is critical to build trustworthy and transparent systems,especially with system security issues coming to the surface.This paper emphasizes the social attributes of objects and uses hypergraphs to model the diverse entities and relationships in SIoT,aiming to build an SIoT hypergraph generation model to explore the complex interactions between entities in the context of intelligent SIoT.Current hypergraph generation models impose too many constraints and fail to capture more details of real hypernetworks.In contrast,this paper proposes a hypergraph generation model that evolves dynamically over time,where only the number of nodes is fixed.It combines node wandering with a forest fire model and uses two different methods to control the size of the hyperedges.As new nodes are added,the model can promptly reflect changes in entities and relationships within SIoT.Experimental results exhibit that our model can effectively replicate the topological structure of real-world hypernetworks.We also evaluate the vulnerability of the hypergraph under different attack strategies,which provides theoretical support for building a more robust intelligent SIoT hypergraph model and lays the foundation for building safer and more reliable systems in the future.展开更多
This paper is set in the high-order finite-difference discretization of the Reynolds-averaged Navier-Stokes(RANS)equations,which are coupled with the turbulence model equations.Three alternative scale-providing variab...This paper is set in the high-order finite-difference discretization of the Reynolds-averaged Navier-Stokes(RANS)equations,which are coupled with the turbulence model equations.Three alternative scale-providing variables for the specific dissipation rate(o)are implemented in the framework of the Reynolds stress model(RSM)for improving its robustness.Specifically,g(=1/√ω)has natural boundary conditions and reduced spatial gradients,and a new numerical constraint is imposed on itω(=lnω)can preserve positivity and also has reduced spatial gradients;the eddy viscosity v,also has natural boundary conditions and its equation is improved in this work.The solution polynomials of the mean-flow and turbulence-model equations are both reconstructed by the weighted compact nonlinear scheme(WCNS).Moreover,several numerical techniques are introduced to improve the numerical stability of the equation system.A range of canonical as well as industrial turbulent flows are simulated to assess the accuracy and robustness of the scale-transformed models.Numerical results show that the scale-transformed models have significantly improved robustness compared to the w model and still keep the characteristics of RSM.Therefore,the high-order discretization of the RANS and RSM equations,which number 12 in total,can be successfully achieved.展开更多
With the requirements of users enhanced for wireless communication, the cooperative communication will become a development trend in future. In this paper, a model based on complex networks with both preferential atta...With the requirements of users enhanced for wireless communication, the cooperative communication will become a development trend in future. In this paper, a model based on complex networks with both preferential attachment is researched to solve an actual network CCN （Cooperative Communication Network）. Firstly, the evolution of CCN is given by four steps with different probabilities. At the same time, the rate equations of nodes degree are presented to analyze the evolution of CCN. Secondly, the degree distribution is analyzed by calculating the rate equation and numerical simulation. Finally, the robustness of CCN is studied by numerical simulation with random attack and intentional attack to analyze the effects of degree distribution and average path length. The results of this paper are more significant for building CCN to programme the resource of communication.展开更多
纹理特征提取是纹理分类中最关键的一步,由于成像条件的不可预知,纹理图像中存在旋转、尺度、噪声等各种因素的变化,给纹理分类的研究工作带来了挑战.为了增强纹理特征提取算法对旋转、尺度和噪声变化的鲁棒性,提出尺度选择完备局部导...纹理特征提取是纹理分类中最关键的一步,由于成像条件的不可预知,纹理图像中存在旋转、尺度、噪声等各种因素的变化,给纹理分类的研究工作带来了挑战.为了增强纹理特征提取算法对旋转、尺度和噪声变化的鲁棒性,提出尺度选择完备局部导数模式(Scale Selective Completed Local Derivative Pattern,SSCLDP).首先,采用自适应中值滤波器对图像进行降噪处理.其次,采用二维高斯滤波器生成该图像的尺度空间.在每个尺度下使用完备局部导数模式(Completed Local Derivative Pattern,CLDP)提取该图像的旋转不变特征,跨尺度取最大值作为该图像的尺度不变特征.将SSCLDP与同类算法在七个公共纹理数据集和热轧带钢图像数据集上进行了实验,实验结果表明,SSCLDP在纹理图像分类和热轧带钢图像分类上有较好的工程应用价值.展开更多
This paper presents a new optimized decentralized controller design method for solving the tracking and disturbance rejection problems for large-scale linear time-invariant systems, using only low-order decentralized ...This paper presents a new optimized decentralized controller design method for solving the tracking and disturbance rejection problems for large-scale linear time-invariant systems, using only low-order decentralized controllers. To illustrate the type of results which can be obtained using the new optimized decentralized control design method, the control of a large flexible space structure is studied and compared with the standard centralized LQR-observer controller. The order of the resultant decentralized controller is much smaller than that of the standard centralized LQR-observer controller. The proposed controller also has certain fail-safe properties and, in addition, it can be five orders of magnitude more robust than the standard LQR-observer controller based on their real stability radii. The new decentralized controller design method is applied to a large flexible space structure system with 5 inputs and 5 outputs and of order 24.展开更多
A time-varying control law via nominal trajectory linearization for an air-breathing hypersonic vehicle （ABHV） model is applied. Feasible guidance command signal serials are generated by nonlinear dynamic inverse （...A time-varying control law via nominal trajectory linearization for an air-breathing hypersonic vehicle （ABHV） model is applied. Feasible guidance command signal serials are generated by nonlinear dynamic inverse （NDI） method considering interactions between aerodynamic effects and propulsion systems. Multiple-time-scale continuous time-varying control, which meets the requirement with accurate, robust, and decoupled tracking of both the commanded trajectory and angular rate profiles in the presence of modeling uncertainties and external disturbances are applied. The simulations for an ABHV model with modeling uncertainties, wind gust, and measuring noises are presented to demonstrate the capacity and reliability of this proposed method.展开更多
文摘The Social Internet of Things(SIoT)integrates the Internet of Things(IoT)and social networks,taking into account the social attributes of objects and diversifying the relationship between humans and objects,which overcomes the limitations of the IoT’s focus on associations between objects.Artificial Intelligence(AI)technology is rapidly evolving.It is critical to build trustworthy and transparent systems,especially with system security issues coming to the surface.This paper emphasizes the social attributes of objects and uses hypergraphs to model the diverse entities and relationships in SIoT,aiming to build an SIoT hypergraph generation model to explore the complex interactions between entities in the context of intelligent SIoT.Current hypergraph generation models impose too many constraints and fail to capture more details of real hypernetworks.In contrast,this paper proposes a hypergraph generation model that evolves dynamically over time,where only the number of nodes is fixed.It combines node wandering with a forest fire model and uses two different methods to control the size of the hyperedges.As new nodes are added,the model can promptly reflect changes in entities and relationships within SIoT.Experimental results exhibit that our model can effectively replicate the topological structure of real-world hypernetworks.We also evaluate the vulnerability of the hypergraph under different attack strategies,which provides theoretical support for building a more robust intelligent SIoT hypergraph model and lays the foundation for building safer and more reliable systems in the future.
基金supported by the National Natural Science Foundation of China(Grant No.12002379)the Natural Science Foundation of Hunan Province in China(Grant No.2020JJ5648)+1 种基金the Scientific Research Project of National University of Defense Technology(Grant No.ZK20-43)the National Key Project(Grant No.GJXM92579).
文摘This paper is set in the high-order finite-difference discretization of the Reynolds-averaged Navier-Stokes(RANS)equations,which are coupled with the turbulence model equations.Three alternative scale-providing variables for the specific dissipation rate(o)are implemented in the framework of the Reynolds stress model(RSM)for improving its robustness.Specifically,g(=1/√ω)has natural boundary conditions and reduced spatial gradients,and a new numerical constraint is imposed on itω(=lnω)can preserve positivity and also has reduced spatial gradients;the eddy viscosity v,also has natural boundary conditions and its equation is improved in this work.The solution polynomials of the mean-flow and turbulence-model equations are both reconstructed by the weighted compact nonlinear scheme(WCNS).Moreover,several numerical techniques are introduced to improve the numerical stability of the equation system.A range of canonical as well as industrial turbulent flows are simulated to assess the accuracy and robustness of the scale-transformed models.Numerical results show that the scale-transformed models have significantly improved robustness compared to the w model and still keep the characteristics of RSM.Therefore,the high-order discretization of the RANS and RSM equations,which number 12 in total,can be successfully achieved.
基金Project supported by the Natural Science Foundation of Beijing(Grant No.4152035)the National Natural Science Foundation of China(Grant No.61272507)
文摘With the requirements of users enhanced for wireless communication, the cooperative communication will become a development trend in future. In this paper, a model based on complex networks with both preferential attachment is researched to solve an actual network CCN （Cooperative Communication Network）. Firstly, the evolution of CCN is given by four steps with different probabilities. At the same time, the rate equations of nodes degree are presented to analyze the evolution of CCN. Secondly, the degree distribution is analyzed by calculating the rate equation and numerical simulation. Finally, the robustness of CCN is studied by numerical simulation with random attack and intentional attack to analyze the effects of degree distribution and average path length. The results of this paper are more significant for building CCN to programme the resource of communication.
文摘纹理特征提取是纹理分类中最关键的一步,由于成像条件的不可预知,纹理图像中存在旋转、尺度、噪声等各种因素的变化,给纹理分类的研究工作带来了挑战.为了增强纹理特征提取算法对旋转、尺度和噪声变化的鲁棒性,提出尺度选择完备局部导数模式(Scale Selective Completed Local Derivative Pattern,SSCLDP).首先,采用自适应中值滤波器对图像进行降噪处理.其次,采用二维高斯滤波器生成该图像的尺度空间.在每个尺度下使用完备局部导数模式(Completed Local Derivative Pattern,CLDP)提取该图像的旋转不变特征,跨尺度取最大值作为该图像的尺度不变特征.将SSCLDP与同类算法在七个公共纹理数据集和热轧带钢图像数据集上进行了实验,实验结果表明,SSCLDP在纹理图像分类和热轧带钢图像分类上有较好的工程应用价值.
文摘This paper presents a new optimized decentralized controller design method for solving the tracking and disturbance rejection problems for large-scale linear time-invariant systems, using only low-order decentralized controllers. To illustrate the type of results which can be obtained using the new optimized decentralized control design method, the control of a large flexible space structure is studied and compared with the standard centralized LQR-observer controller. The order of the resultant decentralized controller is much smaller than that of the standard centralized LQR-observer controller. The proposed controller also has certain fail-safe properties and, in addition, it can be five orders of magnitude more robust than the standard LQR-observer controller based on their real stability radii. The new decentralized controller design method is applied to a large flexible space structure system with 5 inputs and 5 outputs and of order 24.
文摘A time-varying control law via nominal trajectory linearization for an air-breathing hypersonic vehicle （ABHV） model is applied. Feasible guidance command signal serials are generated by nonlinear dynamic inverse （NDI） method considering interactions between aerodynamic effects and propulsion systems. Multiple-time-scale continuous time-varying control, which meets the requirement with accurate, robust, and decoupled tracking of both the commanded trajectory and angular rate profiles in the presence of modeling uncertainties and external disturbances are applied. The simulations for an ABHV model with modeling uncertainties, wind gust, and measuring noises are presented to demonstrate the capacity and reliability of this proposed method.
