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Science China(information Sciences) 2023年第9期66卷 35-49页

作者： Chengcheng FU Hao ZHANG Chao HUANG Zhuping WANG Huaicheng YAN school of Electronic and information engineering Tongji University school of information Science and engineering East China University of Science and Technology

This paper investigates the cooperative output regulation problem of heterogeneous linear parameter-varying multi-agent systems under denial-of-service(DoS) attacks. The matrix and state of the exosystem are taken to be unknown to the followers. Moreover, with the assumption that only a directed spanning tree exists in the communication topology, a resilient observer is proposed to exponentially estimate the global information, which can also be effective under DoS attacks with a certain intensity. Afterward,to avoid using the exact value of the exosystem matrix, a distributed online algorithm is proposed, through which the linear parameter-varying output regulation equation is asymptotically solved. Based on the resilient observer and the solution of the output regulation equation, a distributed regulator is proposed to achieve asymptotic cooperative output regulation for all agents. Some numerical simulations are conducted to verify the effectiveness of the proposed observer, algorithm, and controller.

关键词： cooperative output regulation heterogeneous multi-agent systems DoS attacks linear parameter-varying systems

Stochastic stabilization of Markovian jump systems closed by a communication network: an auxiliary system approach

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Science China(information Sciences) 2023年第10期66卷 229-245页

作者： Guoliang WANG Siyong SONG Chao HUANG school of information and Control engineering Liaoning Petrochemical University College of information and engineering Northeastern University

This study examines the stabilization of continuous-time Markovian jump systems, whose controller is added in the diffusion section. Unlike the traditionally stochastic controllers, the proposed controller is connected by a communication network. Not only the state but also the switching signal is sampled and transmitted. Because the sampling of switching signals makes analyzing and synthesizing the system more difficult, an auxiliary system approach is presented to handle these problems. Particularly, a novel system with an exponential matrix characterizing the sampling effects is developed while the sampling rate is fully considered in the given conditions. Moreover, more special situations of sampled controllers are considered.Two numerical examples are offered to confirm the effectiveness and superiority of the methods proposed in this study.

关键词： Markovian jump system Brownian motion sampled switching signal stochastic stabilization networked control

When the gain of predictive resource allocation for content delivery is large?

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Science China(information Sciences) 2023年第12期66卷 179-193页

作者： Chenzuo ZHANG Jia GUO Chenyang YANG school of Electronic and information engineering Beihang University

By predicting future information such as data rate with sensory wireless data, radio resources can be pre-allocated for content delivery. Such an integrated sensing and communications technique can help improve network performance and user experience. To justify the cost paid for predicting future information,it is important to understand in which scenarios predictive resource allocation yields a large gain over the non-predictive counterpart. In this paper, we strive to identify the key factors that affect the gain of predictive resource allocation by deriving the closed-form expression of the gain. We are concerned with minimizing the transmission time required for content delivery such as file downloading to users with an expected deadline,where the resources of base stations are shared with real-time services. Then, the performance gain is measured by the difference of the average time required by predictive and non-predictive resource allocation.Inspired by the solution of the optimization problem, we resort to the theory of order statistics for deriving the performance gain. We find that the gain depends on the statistics(i.e., mean value and standard deviation)of the user’s average data rates in the prediction window. Then, we separately analyze how the statistics of the bandwidth available for content delivery and user mobility affect the gain. We use simulation with a real dataset of traffic load to validate the analysis and quantify the impact of the key factors. Our results show that predictive resource allocation can reduce the transmission time even for non-moving users. The performance gain is high when the network is busy or the cell radius is large.

关键词： predictive resource allocation performance analysis average data rates residual bandwidth user mobility

Temporal Modal Analysis of Small Radiators

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Chinese Journal of Electronics 2022年第6期31卷 1112-1120页

作者： WU Qi The school of Electronic and information engineering Beihang University

Resonance is a common physical phenomenon in real world, and the modal analysis is a useful tool. Within the regime of electromagnetics, characteristic mode theory is established in frequency domain(FD),and it is doubtful that whether we can find similar modes in time domain(TD). In this paper, resonating modes of a vibrating string are briefly reviewed. Special attentions are paid to the time-domain behaviors of the resonating modes, by following which a temporal modal analysis is proposed. Additionally, a narrow plate is selected as an example since it has a similar structure as the vibrating string. Temporal modal behaviors of the plate are presented and discussed. To further demonstrate this concept, a rigorous analysis of a sphere is provided. A frequency-independent condition is discussed and verified for small objects, and it results in a band-limited constraint. In addition, the temporal modal analysis with excitations is presented, and its potential applications are discussed with emphasis on the analyzing and optimizing transient behaviors of antennas. This work expands largely the field of characteristic mode and may find applications for scattering and antennas.

关键词： Characteristic modes Fourier transform Time domain

Network Element Placement for Space-Air-Ground Integrated Network:A Tutorial

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Chinese Journal of Electronics 2022年第6期31卷 1013-1024页

作者： GENG Yuhui CAO Xianbin CUI Huanxi XIAO Zhenyu school of Electronic and information engineering Beihang University

With the demand for Internet connectivity in remote areas, the space-air-ground integrated network(SAGIN) was proposed to achieve ubiquitous coverage and enhance service capabilities of extant terrestrial networks. The paradigm of virtual network element placement(NEP) is applied into SAGIN. It can save energy and operating costs by placing specific network elements(NEs) as software instances. In addition, it helps to provide services in end-to-end networks with its ability to allocate and manage resources flexibly. However, NEP faces some challenges in SAGIN. The network topologies can be dynamic, and links such as the satellite-to-ground and air-to-ground ones are prone to fail. These will make NEP management more complicated. Moreover, the static NEP schemes are hard to accommodate the time-varying traffic. In this context, this work explains the NEP problem in SAGIN from three aspects, i.e., the SAGIN radio access network(RAN), the SAGIN core network(CN), and the SAGIN barrier network(BN). First, the physical and networking architectures of SAGIN are introduced. Then the status of the network element placement and corresponding challenges are described from these two aspects. Finally, this paper discusses future research directions and key technical challenges.

关键词： Network element placement Space-airground integrated network (SAGIN) Software defined network (SDN) Network function virtualization (NFV) Network architectures Resource allocation

Adaptive Barrier-Lyapunov-Functions Based Control Scheme of Nonlinear Pure-Feedback Systems with Full State Constraints and Asymptotic Tracking Performance

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Journal of Systems Science & Complexity 2024年第3期37卷 965-984页

作者： NIU Ben WANG Xiaoan WANG Xiaomei WANG Xinjun LI Tao Faculty of Electronic information and Electrical engineering Dalian University of Technology school of information Science and engineering Shandong Normal University school of Mathematics Southeast University school of Automation Nanjing University of Information Science and Technology

In this paper, the authors propose an adaptive Barrier-Lyapunov-Functions(BLFs) based control scheme for nonlinear pure-feedback systems with full state constraints. Due to the coexist of the non-affine structure and full state constraints, it is very difficult to construct a desired controller for the considered system. According to the mean value theorem, the authors transform the pure-feedback system into a system with strict-feedback structure, so that the well-known backstepping method can be applied. Then, in the backstepping design process, the BLFs are employed to avoid the violation of the state constraints, and neural networks(NNs) are directly used to online approximate the unknown packaged nonlinear terms. The presented controller ensures that all the signals in the closed-loop system are bounded and the tracking error asymptotically converges to zero. Meanwhile, it is shown that the constraint requirement on the system will not be violated during the operation. Finally, two simulation examples are provided to show the effectiveness of the proposed control scheme.

关键词： Asymptotic tracking control barrier Lyapunov functions full state constraints nonlinear pure-feedback systems

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MFVNet: a deep adaptive fusion network with multiple field-of-views for remote sensing image semantic segmentation

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Science China(information Sciences) 2023年第4期66卷 93-106页

作者： Yansheng LI Wei CHEN Xin HUANG Zhi GAO Siwei LI Tao HE Yongjun ZHANG school of Remote Sensing and information engineering Wuhan University

In recent years, the remote sensing image(RSI) semantic segmentation attracts increasing research interest due to its wide application. RSIs are difficult to be processed holistically on current GPU cards on account of their large field-of-views(FOVs). However, the prevailing practices such as downsampling and cropping will inevitably decrease the quality of semantic segmentation. To address this conflict,this paper proposes a new deep adaptive fusion network with multiple FOVs(MFVNet), which is specially designed for RSI semantic segmentation. Different from existing methods, MFVNet takes into consideration the differences among multiple FOVs. By pyramid sampling the RSI, we first obtain images on different scales with multiple FOVs. Images on the high scale with a large FOV can capture larger spatial contexts and complete object contours, while images on the low scale with a small FOV can keep the higher spatial resolution and more detailed information. Then scale-specific models are chosen to make the best predictions for all scales. Next, the output feature maps and score maps are aligned through the scale alignment module to overcome spatial misregistration among scales. Finally, the aligned score maps are fused with the help of adaptive weight maps generated by the adaptive fusion module, producing the fused prediction. The performance of MFVNet surpasses the previous state-of-the-art semantic segmentation models on three typical RSI datasets, demonstrating the effectiveness of the proposed MFVNet.

关键词： semantic segmentation remote sensing image (RSI) field-of-view (FOV) adaptive fusion convolutional neural network

Input-to-State Stability for Impulsive Switched Singular Systems with Mismatched Disturbances

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Journal of Systems Science & Complexity 2024年第3期37卷 924-946页

作者： YANG Anqing MA Shuping school of information engineering Shandong Management University school of Mathematics Shandong University

This work investigates the input-to-state stability(ISS) problem for impulsive switched singular systems(ISSSs) with mismatched disturbances. In this paper, ‘disturbance’ is a general concept that includes model uncertainty, unknown system dynamic, external disturbance, etc. The modified uncertainty and disturbance estimator(UDE)-based control method is presented for singular systems and ISSSs, a virtual control is introduced to offset the effects of mismatched disturbances. On the basis of a discontinuous multiple Lyapunov functional and admissible edge-dependent average dwell time(AED-ADT) method, several sufficient conditions in terms of linear matrix inequalities(LMIs)are obtained to ensure that the closed-loop systems are regular, impulse-free and ISS. Finally, two examples are given to demonstrate the effectiveness of the proposed results.

关键词： Impulsive switched singular systems input-to-state stability UDE-based control

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Blockchain Data Analysis from the Perspective of Complex Networks:Overview

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Tsinghua Science and Technology 2023年第1期28卷 176-206页

作者： Wanshui Song Wenyin Zhang Jiuru Wang Linbo Zhai Pengkun Jiang Shanyun Huang Bei Li school of information Science and engineering Shandong Normal UniversityJinan 250307China school of information Science and engineering Linyi UniversityLinyi 276005China

Cryptocurrency based on blockchain technology has gradually become a choice for people to invest in,and several users have participated in the accumulation of massive transaction data.Complete transaction records in blockchains and the openness of data provide researchers with opportunities to mine and analyze data in blockchains.Network modeling and analysis of cryptocurrency transaction records are common methods in blockchain data analysis.The analysis of attribute graphs can provide insights into various economic indicators,illegal activities,and general Internet security,among others.Accordingly,this article aims to summarize and analyze the literature on cryptocurrency transaction data from the perspective of complex networks.To provide systematic guidance for researchers,we put forward a blockchain data analysis framework based on the introduction of the relevant background and reviewed the work from five aspects:blockchain data model,data acquisition on blockchains,existing analysis tools,available insights,and common analysis methods.For each aspect,we introduce the research problems,summarize the methods,and discuss the results and findings.Finally,we present future research points and several open questions in the study of cryptocurrency transaction networks.

关键词： blockchain cryptocurrency transaction record complex network data analysis data mining

Vulnerability analysis of the Chinese coupled aviation and high-speed railway network

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Chinese Journal of Aeronautics 2022年第12期35卷 189-199页

作者： Yiqiao WANG Xianbin CAO Fangyun QIN Lu(Carol)TONG school of Electronic and information engineering Beihang UniversityBeijing 100191China school of information engineering Capital Normal UniversityBeijing 100191China

The integrated aviation and High-Speed Railway(HSR)transportation system plays a vital role for today’s inter-city transportation services.However,an increasing number of unexpected disruptions(such as operation failures,natural disasters,or intentional attacks)pose a considerable threat to the normal operation of the system,especially on ground transfer,leading to the extensive research on its vulnerability.Previous approaches mainly focus on interruptions within a single transportation mode,neglecting the role of ground transfer which serves as a coupled connection between aviation and High-Speed Railway.This paper proposes a network-based framework for evaluating the vulnerability of the Chinese Coupled Aviation and High-Speed Railway(CAHSR)network from the viewpoint of ground transfer interruption.Taking the end-to-end travel time and passenger flow information into consideration as an evaluation measure and analyzing from the perspective of urban agglomerations,an adaptive method is developed to identify the critical cities and further investigate their failure impacts on the geographic distribution of vulnerability.In addition,the proposed model explores variations of vulnerability under different failure time intervals.Based on the empirical study,some major conclusions are highlighted as follows:(A)Only a few cities show significant impacts on the network’s vulnerability when ground transfer interruptions occurred.(B)The distribution of vulnerability is not proportional to the distance between failure city and influenced city.(C)The vulnerability is more serious in the morning and evening when the ground transfer is disconnected.Our findings may provide new insights for maintenance and optimization of the CAHSR network and other real-world transportation networks.

关键词： Air transportation Complex networks Railway network Transfer Vulnerability

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