ROBUST ADAPTIVE CONTROL OF NONHOLONOMIC SYSTEMS WITH UNCERTAINTIES

Robust adaptive control of nonholonomic systems in chained form with linearly parameterized and strongly nonlinear disturbance and drift terms is dicussed.The novelty of the proposed method is a combined use of the state-scaling and the back-stepping procedure.

A Survey on the Control Lyapunov Function and Control Barrier Function for Nonlinear-Affine Control Systems

This survey provides a brief overview on the control Lyapunov function(CLF)and control barrier function(CBF)for general nonlinear-affine control systems.The problem of control is formulated as an optimization problem where the optimal control policy is derived by solving a constrained quadratic programming(QP)problem.The CLF and CBF respectively characterize the stability objective and the safety objective for the nonlinear control systems.These objectives imply important properties including controllability,convergence,and robustness of control problems.Under this framework,optimal control corresponds to the minimal solution to a constrained QP problem.When uncertainties are explicitly considered,the setting of the CLF and CBF is proposed to study the input-to-state stability and input-to-state safety and to analyze the effect of disturbances.The recent theoretic progress and novel applications of CLF and CBF are systematically reviewed and discussed in this paper.Finally,we provide research directions that are significant for the advance of knowledge in this area.

Evidence of Scaling in Chinese Income Distribution

与从在 1998-2002 的中国家庭收入工程的收入数据，我们学习中国收入分发的功能的形式。恰当的结果加一条幂定律尾巴建议木头正常分布。这种分布形式外面在中国的改革和拐弯的早阶段从它的外观改变了很多与一些完全的市场经济的一致。出售改革引起的收入生长率的无常和差异是当前的中国收入分发的主要原因。[从作者抽象]

Synthesis of tetrapod-shaped ZnO whiskers and microrods in one crucible by thermal evaporation of Zn/C mixtures

Tetrapod-shaped ZnO whiskers and microrods were synthesized in one crucible by thermal evaporation of Zn/C mixtures at 930 ℃ in air without any catalyst.The digital camera,optical microscopy,scanning electron microscopy,energy dispersive X-ray spectroscopy,and X-ray diffraction techniques were used to study the morphologies and crystal structures of these tetrapod-shaped ZnO microcrystals.The results show that these two types of ZnO tetrapods are grown at different heights within the same crucible.The legs of these tetrapod-shaped ZnO crystals are hexagonally faceted.Some tetrapod-shaped ZnO whiskers show hierarchical structures.A short button-like hexagonal ZnO microcrystal is observed at the triple junctions of some tetrapod-shaped ZnO whiskers.The tetrapod-shaped ZnO microrods are capped by two sets of hexagonal pyramids with two different groups of crystal planes for the surfaces.These two types of tetrapod-shaped ZnO microcrystals have different side faces and aspect ratio,which are believed to be the result of their different growth behaviors.The octa-twin model was used to discuss the different growth behaviors of these two types of ZnO tetrapods.The crystal planes of the legs and the pyramids were determined.

The Effect of Time, Percent of Copper and Nickel on the Natural Precipitation Hardness of Al – Cu – Ni Powder Metallurgy Alloys Using Design of Experiments

In this investigation, the effect of time, percentage of copper and nickel on the hardness property of aluminum based powder metallurgy alloys were studied. A full factorial analysis with four levels for each factor was used. The samples were produced using powder metallurgy process, and then subjected to natural aging where heat treatment was conducted for all samples together at 550°C for 3 hours before quenching in water. Then, the samples were left at room temperature for 936 hours (39 days) to allow traces atoms to diffuse and form coherent phases which increase the hardness. It was found that the hardness was firstly increased with time for about 300 hours after the quenching time, and then it tends to remain constant after that. However, the hardness drop at overage stage was not observed until the end of 936 hours. To get a full analysis of the natural aging we used design of experiment tool to study the effect of %Cu, %Ni and aging time on the hardness. The results showed that the hardness was influenced significantly by all considered factors and interactions between them.

Statistical distribution of Chinese names

This paper studies the statistical characteristics of Chinese surnames,first names and full names based on a credible sample.The distribution of Chinese surnames,unlike that in any other countries,shows an exponential pattern in the top part and a power-law pattern in the tail part.The distributions of Chinese first names and full names have the characteristics of a power law with different exponents.Finally,the interrelation of the first name and the surname is demonstrated by using a computer simulation and an exhibition of the name network.Chinese people take the surname into account when they choose a first name for somebody.

Multi-objective robust controller synthesis for discrete-time systems with convex polytopic uncertain domain

Multi-objective robust state-feedback controller synthesis problems for linear discrete-time uncertain systems are addressed. Based on parameter-dependent Lyapunov functions, the Gl2 and GH2 norm expressed in terms of LMI (Linear Matrix Inequality) characterizations are further generalized to cope with the robust analysis for convex polytopic uncertain system. Robust state-feedback controller synthesis conditions are also derived for this class of uncertain systems. Using the above results, multi-objective state-feedback controller synthesis procedures which involve the LMI optimization technique are developed and less conservative than the existing one. An illustrative example verified the validity of the approach.

Evolution analysis of the states of the EZ model

Based on suitable choice of states, this paper studies the stability of the equilibrium state of the EZ model by regarding the evolution of the EZ model as a Markov chain and by showing that the Markov chain is ergodic. The Markov analysis is applied to the EZ model with small number of agents, the exact equilibrium state for N = 5 and numerical results for N = 18 are obtained.

Size Dependency of Income Distribution and Its Implications

We systematically study the size dependency of income distributions,i.e.income distribution versus the population of a country.Using the generalized Lotka--Uolterra model to fit the empirical income data for 1996-2007 in the U.S.A,we find an important parameter A that can scale with aβpower of the size(population)of the U.S.A.in that year.We point out that the size dependency of income distributions,which is a very important property but seldom addressed in previous studies,has two non-trivial implications:(1)the allometric growth pattern,i.e.the power-law relationship between population and GDP in different years,can be mathematically derived from the size-dependent income distributions and also supported by the empirical data;(2)the connection with the anomalous scaling for the probability density function in critical phenomena,since the re-scaled form of the income distributions has asymptotically exactly the same mathematical expression for the limit distribution of the sum of many correlated random variables.

Response of Stretched Cylindrical Diffusion Flame to Sinusoidal Oscillation of Air Flow Velocity

试验性的研究调查了拉长的圆柱的散开火焰的特征，与关于空气溪流的凸的弯曲，响应周期的空气流动速度摆动。燃料甲烷与氮，和氧化剂空气被冲淡。摆动频率从 5 ～ 250 Hz 被改变。结果如下被总结。尽管空气溪流速度坡度的变化振幅关于频率是不变的，燃料溪流的振幅增加了。火焰半径的变化振幅从 5 ～ 25 Hz 伪稳定地变化了，并且与在比 50 Hz 大的频率范围增加频率减少了。火焰光明没在 5 Hz 伪稳定地反应，并且火焰光明的摆动振幅是不到稳定的火焰的，在一样的速度变化范围上。光明的摆动振幅在 50 Hz 达到顶点，并且比稳定的火焰的大。在关于频率的火焰光明的这个复杂变化是，这被考虑仔细，与在在火焰的比率的各自的时间变化的阶段差别有关，到半径，空气的速度坡度和燃料溪流的厚度，和这些的大小珍视，与到与火焰弯曲效果有关的半径的火焰厚度的比率，空气溪流的速度坡度相关到火焰段效果。

Visibility graph approach to extreme event series

An extreme event may lead to serious disaster to a complex system.In an extreme event series there exist generally non-trivial patterns covering different time scales.Investigations on extreme events are currently based upon statistics,where the patterns are merged into averages.In this paper from extreme event series we constructed extreme value series and extreme interval series.And the visibility graph is then adopted to display the patterns formed by the increases/decreases of extreme value or interval faster/slower than the linear ones.For the fractional Brownian motions,the properties for the constructed networks are the persistence,threshold,and event-type-independent,e.g.,the degree distributions decay exponentially with almost identical speeds,the nodes cluster into modular structures with large and similar modularity degrees,and each specific network has a perfect hierarchical structure.For the volatilities of four stock markets(NSDQ,SZI,FTSE100,and HSI),the properties for the former three's networks are threshold-and market-independent.Comparing with the factional Brownian motions,their degree distributions decay exponentially but with slower speeds,their modularity behaviors are significant but with smaller modularity degrees.The fourth market behaves similar qualitatively but different quantitatively with the three markets.Interestingly,all the transition frequency networks share an identical backbone composed of nine edges and the linked graphlets.The universal behaviors give us a framework to describe extreme events from the viewpoint of network.

Power-Law Tail in the Chinese Wealth Distribution

我们从最富有的 Chinesefrom 一年的最近出版的表分析数据 2003 ～ 2005。结果证实在这些年里，财富在高端根据有在 1.758 和 2.285 之间的代表的一条幂定律是分布式的。尽管在表的人急速地变化，力量分发被发现相当柔韧，财富很快增加。在财富和财富的绝对变化之间的关系拒绝财富进化是一个趋于增加的随机的过程的观点。

NETLAB-An Internet based laboratory for electrical engineering education

This article describes an Internet based laboratory (NETLAB) developed at Zhejiang University for electrical engi- neering education. A key feature of the project is the use of real experimental systems rather than simulation or virtual reality. NELTAB provides remote access to a wide variety of experiments, including not only basic electrical and electronic experiments but also many innovative control experiments. Students can effectively use the laboratory at any time and from anywhere. NETLAB has been in operation since July 2003.

Oscillatory and anti-oscillatory motifs in genetic regulatory networks

Recently,self-sustained oscillatory genetic regulatory networks(GRNs) have attracted significant attention in the biological field.Given a GRN,it is important to anticipate whether the network could generate oscillation with proper parameters,and what the key ingredients for the oscillation are.In this paper the ranges of some function-related parameters which are favorable to sustained oscillations are considered.In particular,some oscillatory motifs appearing with high-frequency in most of the oscillatory GRNs are observed.Moreover,there are some anti-oscillatory motifs which have a strong oscillation repressing effect.Some conclusions analyzing these motif effects and constructing oscillatory GRNs are provided.

Networked Knowledge and Complex Networks:An Engineering View

Along with the development of information technologies such as mobile Internet,information acquisition technology,cloud computing and big data technology,the traditional knowledge engineering and knowledge-based software engineering have undergone fundamental changes where the network plays an increasingly important role.Within this context,it is required to develop new methodologies as well as technical tools for network-based knowledge representation,knowledge services and knowledge engineering.Obviously,the term“network”has different meanings in different scenarios.Meanwhile,some breakthroughs in several bottleneck problems of complex networks promote the developments of the new methodologies and technical tools for network-based knowledge representation,knowledge services and knowledge engineering.This paper first reviews some recent advances on complex networks,and then,in conjunction with knowledge graph,proposes a framework of networked knowledge which models knowledge and its relationships with the perspective of complex networks.For the unique advantages of deep learning in acquiring and processing knowledge,this paper reviews its development and emphasizes the role that it played in the development of knowledge engineering.Finally,some challenges and further trends are discussed.

Memoryless cooperative graph search based on the simulated annealing algorithm

We have studied the problem of reaching a globally optimal segment for a graph-like environment with a single or a group of autonomous mobile agents. Firstly,two efficient simulated-annealing-like algorithms are given for a single agent to solve the problem in a partially known environment and an unknown environment,respectively. It shows that under both proposed control strategies,the agent will eventually converge to a globally optimal segment with probability 1. Secondly,we use multi-agent searching to simultaneously reduce the computation complexity and accelerate convergence based on the algorithms we have given for a single agent. By exploiting graph partition,a gossip-consensus method based scheme is presented to update the key parameter-radius of the graph,ensuring that the agents spend much less time finding a globally optimal segment.

Wave Instability and Spatiotemporal Chaos in Reaction-Diffusion System with Oscillatory Dynamics

我们用理论、数字的方法在摆动的媒介调查一致振荡器的象 Turing 一样波浪不稳定性。一个宣传波浪模式在系统的角落发源当一致振荡器经由 Turing-likewave 变得不稳定时，出现不稳定性。到 quasi-periodicallypropagated 的从周期性地宣传的波浪模式的分叉挥动模式，然后发生到空间与时间的混乱，，从一致振荡器的茶碱稳定性阀值的系统尺寸增加。

Self-Similarity in Game-Locked Aggregation

A collective game is studied via agent-based modeling approach,where a group of adaptive learning players seek for their best positions on a vertical line.The movements of players are driven by benefits obtained from interactions.The game falls into an evolutionary stable state,at which aggregations of players on the line emerge.The pattern of these aggregates exhibits self-similarity at different scales with a fractal dimension of 0.58.The underlying mechanism of this aggregation is unique in that aggregates are resulted from mutual lock-in of players.This game-locked aggregation,in contrast with the diffusion limited aggregation,is applicable to a broader scope of aggregation processes.

Information flow between stock markets:A Koopman decomposition approach

Stock markets in the world are linked by complicated and dynamical relationships into a temporal network.Extensive works have provided us with rich findings from the topological properties and their evolutionary trajectories,but the underlying dynamical mechanism is still not in order.In the present work,we proposed a technical scheme to reveal the dynamical law from the temporal network.The index records for the global stock markets form a multivariate time series.One separates the series into segments and calculates the information flows between the markets,resulting in a temporal market network representing the state and its evolution.Then the technique of the Koopman decomposition operator is adopted to find the law stored in the information flows.The results show that the stock market system has a high flexibility,i.e.,it jumps easily between different states.The information flows mainly from high to low volatility stock markets.And the dynamical process of information flow is composed of many dynamic modes distribute homogenously in a wide range of periods from one month to several ten years,but there exist only nine modes dominating the macroscopic patterns.