Abstract:In order to reduce the unnecessary waste of limit network resources such as network bandwidth,communication cost,and agents' energy,the investigation of event-triggered schemes has become a hot research topic and attracted numerous scholars' attention.This paper mainly discusses several classical event-triggered schemes,i.e.centralized,clustered and distributed event-triggered schemes,self-triggered schemes and edge event-triggered schemes.The research background and the recent results about the above schemes are specifically introduced.Note that the exclusion of Zeno behavior is a key problem of analyzing the effectiveness of event-triggered schemes.This paper points out a flaw of excluding Zeno behavior in the early related research,and then summarizes two basic methods to avoid this behavior.Finally,this paper provides some future research works of event-triggered schemes,and their theoretical or application research.

Abstract:Recently,the studies of urban public transportation networks based on complex network have attracted extensive attention,relevant research findings are helpful to understand the operation mechanism of urban public transport network in depth,and will aid the design,optimization and control of such networks.This paper first introduces the research background,the network description and some related network concepts of urban public transportation networks,then summarizes and analyzes the research status from aspects of static characteristic analysis,evolutionary generation modeling,behavior study,and application research.Finally,the current research situation and development opportunities for urban public transportation networks based on complex network are summarized and discussed.

Abstract:With the rapid development of the Internet,the information keeps explosive growth.It is clear that understanding the characteristics of the Internet information is important to,for example,fast acquisition of the information from the Internet.A survey on the development of the characteristics of the Internet information is presented in this paper.Firstly,the characteristic of the carrier of the Internet information is discussed.Secondly,the characteristics of the Internet information in terms of time evolution,information scale,information content,and types of information files,are analyzed and summarized.Finally,the possible application of the characteristics of the Internet information is discussed.

Abstract:Recently,swarming behavior for multi-agent systems has been a hot research topic in the field of complex network.In this paper,starting from the two factors of the intrinsic dynamics of agent and the topology structure,the development status of swarming behavior in the multi-agent system is summarized,and then the corresponding distributed protocol,convergent speed and the condition of implementation are introduced and analyzed.Finally,combined with the current research status,the future research directions of swarming behavior are discussed.

Abstract:The leader-following consensus of multi-agent systems is analyzed,where the dynamic of each agent is modeled by a fractional-order singular linear system in this paper.A new control protocol is designed based on the information of outputs.A sufficient condition of leader-following consensus is derived through some proof.Furthermore,the consensus condition is expressed by LMI via singular value decomposition technique (SVD).When the communication topology is assumed to be an undirected graph,the consensus condition is simplified as several simple LMIs.A simulation example is given to show how to solve feedback gain.It can be seen that the results in the paper are correct and effective from the pictures.

Abstract:This paper considers the problem of fixed-time synchronization for a class of second-order nonlinear multi-agent systems with a leader-follower architecture.Based on the homogeneous system theory,a new fixed-time synchronization control algorithm is designed such that the synchronization of multiple master-slave coupling systems can be achieved in a fixed time.It is theoretically shown that the synchronization time can be pre-determined which is independent of any initial conditions.Numerical simulations on synchronization of multi-agent systems are finally performed to illustrate the effectiveness of the proposed method.

Abstract:The distributed target estimation problem in a wireless sensor network (WSN) which is under network attack is studied in this paper.Due to the limited measurement range,only some sensors in WSN can measure the target,and at the same time,the nodes are randomly attacked so that the measurement value is injected into false information.An improved consensus Kalman filter algorithm based on the attack detection and recognition strategy is proposed.In this algorithm,firstly,the node judges whether it is attacked based on the attack recognition threshold given in this paper.Secondly,a consensus Kalman filtering algorithm is designed based on the minimum trace fusion principle.Finally,the convergence of the algorithm is analyzed,and a sufficient condition of the attack probability for the boundedness of the mean-square estimation error in WSN is given.Besides,numerical simulations are given to verify the effectiveness and superiority of the algorithm.

Abstract:This paper proposes a cascade-based control algorithm for distributed consensus tracking of multi-underactuated surface vessels(USVs) system.The presented control algorithm can be divided into two parts.The first part is a distributed control estimator under sampled interactions,which is used to estimate the leader's trajectory.The second part is the local control law,driving each USV to track the obtained estimated trajectory by invoking sliding mode control combined with the radical basis function neural network in terms of the underactuated feature,environmental disturbance and model uncertainties.Besides,in order to solve the presented tracking problem,several sufficient conditions are obtained via Lyapunov theory and cascade system theory to ensure that the position states of all USVs converge to the desired position.The simulation results show the correctness and effectiveness of the proposed theorem.

Abstract:Bitcoin draws the highest degree of attention among cryptocurrencies,while coin mining is one of the most important fashion of profiting in the Bitcoin ecosystem.This paper constructs fresh coin circulation networks by tracking the fresh coin transfer routes through analysis of the transaction referencing in Bitcoin blockchain.A heuristic algorithm is proposed to identify coin miners by comparing coin circulation networks from different mining pools and thereby infer their commonly used mining rewards distribution schemes.Furthermore,this paper characterizes the increasing trend of Bitcoin miner numbers during recent years.

Abstract:In this paper,the distributed optimization problem of multi-agent system with Lipschiz-type nonlinear dynamics is studied.For a multi-agent system,each agent has a local performance function.The quality of the whole multi-agent network is judged by the sum of these local performance functions.In the whole process,each agent only knows local interaction information and the gradient of its own objective function.In order to achieve the goal of cooperative optimization,a new distributed optimization algorithm is proposed.Furthermore,by utilizing the Lyapunov stability and optimization analysis,the distributed cooperative optimization problems for Lipschiz-type nonlinear multi-agent systems are solved.Finally,a numerical simulation is shown to verify the effectiveness of the proposed algorithm.

Abstract:This paper considers the containment control problem for general linear multi-agent systems which have communication topologies with non-cooperative edges.It admits multiple leaders which are dynamically changing via interactions between themselves and the neighboring leaders.A distributed control protocol is designed with the nearest neighbor rule.By using the linear matrix inequality technique and the linear system control theory,it is shown that the followers' state trajectories can converge to the convex hull formed by each leader's trajectory as well as its symmetric trajectory,and the containment control problem for linear multi-agent system over signed graph can be achieved.Simulation results are performed to verify the correctness of the conclusion.

Abstract:To accurately retrieve the macro-and micro-physical parameters of cloud by means of radar echoes,the developed millimeter-wave cloud radar must be calibrated.In this paper,several domestic and abroad calibration methods are introduced,such as the calibration of the contribution of individual system parameters;the calibration of raindrop,triangular corner reflectors and metal sphere;the calibration using the backscattering technology of ocean surface,Cloudsat as radar calibrator.These calibration methods are of great value for the application of domestic millimeter-wave cloud radar in practical remote sensing.

Abstract:Under the condition of partial shadow,the power-voltage (P-V) characteristic curve of photovoltaic array presents multiple peaks.In the multi-peak case,the conventional maximum power point tracking (MPPT) algorithm is prone to fall into local optimal solution,which affects the solar energy conversion efficiency.This paper presents an MPPT algorithm based on fuzzy control with load voltage scan.At first,the voltage scanning method is used to quickly reach the maximum power point,and then the fuzzy control algorithm is used to stabilize the maximum power point.The algorithm improves the convergence speed of MPPT under multi-peak condition,which can solve the problem of voltage spike produced on the switch tube during the particle switching.The feasibility and practicability of the algorithm are verified by Matlab simulation and hardware experiments.

Abstract:After SUM06 and AOT40,the cumulative stomatal ozone uptake fluxes (AFstY) methods have been widely used in ozone risk assessment.But the threshold Y of the flux model cannot well reflect plant's antioxidant ability and self-repair ability to ozone exposure.How to dynamically simulate the plant's own defense mechanisms is particularly important to improve the accuracy of ozone risk assessment.This article discusses how to quantify the plant's defense against ozone based on measurement results of other researchers.The photosynthetic quantitative method is used to simulate the damage threshold dynamically and calculate the effective uptake fluxes of ozone.The SODA model is used to discuss the effect of ascorbic acid in the cell to the plasma membrane flux of ozone from two aspects of stomatal absorption and apoplast detoxification.The results provide a new perspective for ozone flux model,and lay the foundation for ozone stress effect research.

Abstract:The main problem in nanosecond pulse signal measurement is narrow bandwidth and distorted waveform.Based on the square wave calibration data of the measurement system,a difference equation model and a convolution model of the measurement system are established,which are used in the actual test of the double exponential pulse waveform prediction and reconstruction for signal processing.Model results show that the convolution model is more suitable than differential equation model in the nanosecond pulse waveform prediction and reconstruction.

Abstract:Based on the reanalysis data of ZJ-WARMS with three hours interval,conventional sounding data and Lin'an Dual-polarization Radar data products,the typical features of the first snowfall in Zhejiang area on Dec.5,2015 are studied.It is showed that the high temperature near surface and low temperature in middle and low levels,combined with the mountainous topography in the northwest region of Zhejiang province are the main causes.The typical characteristics of dual-polarization radar products on this type of snowfall in Zhejiang area are summarized,and the threshold value of discrimination is obtained consequently,with the purpose to improve the predictability of this kind of snowfall.

Abstract:We analyzed the effect of tall buildings on the lightning return-stroke electromagnetic fields by using finite-difference time-domain (FDTD) technique.Results show that tall buildings have obvious effect on the return-stroke electric fields and weak effect on magnetic fields(less than 10% when the building is 50 m high).The electric field at the top of buildings is closely related with the building height,and the vertical/horizontal component of the electric field gradually increases/decreases with the increase of building height.When the building is high as 20 m,50 m,and 100 m,the vertical electric field at the building top is 1.3,1.7,and 2 times of that at the ground level,respectively,while the horizontal one is 0.9,0.8,and 0.7 times,respectively.We also analyzed the factors influencing the electric fields near tall buildings.The ground level horizontal electric field is obviously affected by the ground surface finite conductivity,the greater the soil conductivity,the faster the negative amplitude decays.While the horizontal electric field above the ground is affected by the buildings as well as the observation point location.

Abstract:Using the data of thunderstorm days recorded by 74 ground meteorological observatories in Hunan province from 1961 to 2010,the climatic characteristics of thunderstorms during the past 50 years were analyzed by means of mathematical statistics,wavelet analysis and Mann-Kendall test.The results show that there is a deceasing trend of thunderstorm days from the north to the south,with the highest number of thunderstorm days in the mountainous region of the south for 65.38 d/a,and the lowest number of thunderstorm days in the plain of the north for 21.92 d/a.The distribution of average monthly thunderstorm days are observed to be a single peak curve,with the peak period appear in March to September.The oscillation periods of 8 years,16 years,24 years and 30 years are found in the number of average annual thunderstorm days in Hunan,with most remarkable period being 8 years.The climatic difference between the periods with more or less thunderstorm days appears as the position of westward move of the subtropical high over the Western Pacific,as well as the position and strength of short-wave trough of Tibetan Plateau.

Abstract:A lightning parameter inquiry system is designed and implemented using MapX5.0,Microsoft SQL Server 2008 and C# programming language under. NET4.0 development environment.Combined lightning data with geographic information,this system can realize functions of query and editing of geographic information,storage and management of original lightning data,query and analysis of lightning parameters,and drawing and output of thematic maps.For instance,this paper takes the Wuhan city circle,which includes 9 cities of Wuhan,Xiaogan,Tianmen,Qianjiang,Xiantao,Xianning,Ezhou,Huangshi and Huanggang,to implement this GIS based inquiry system,and shows the results of lightning parameter inquiry,thematic map drawing,position of lightning occurrence and observation station,and distribution of lightning current intensity.