Distributed consensus of a class of networked heterogeneous multi-agent systems

In this paper, we consider the consensus problem of a class of heterogeneous multi-agent systems composed of the linear first-order and second-order integrator agents together with the nonlinear Euler–Lagrange (EL) agents. First, we propose a distributed consensus protocol under the assumption that the parameters of heterogeneous system are exactly known. Sufficient conditions for consensus are presented and the consensus protocol accounting for actuator saturation is developed. Then, by combining adaptive controller and PD controller together, we design a protocol for the heterogeneous system with unknown parameters (in the nonlinear EL dynamics). Based on graph theory, Lyapunov theory and Barbalat's Lemma, the stability of the controllers is proved. Simulation results are also provided to illustrate the effectiveness of the obtained results.     

Containment control of singular heterogeneous multi-agent systems

In this paper, we first consider the containment control problem of singular heterogeneous multi-agent systems, where all the followers converge to the convex hull spanned by the leaders. To solve this problem, we propose two distributed control laws: one is based on the state feedback control framework, which is suitable for the case that the full state information of each follower is accessible; and the other is based on the output regulation framework, where each follower only can access to its output. Furthermore, the distributed observers are designed for every follower to estimate the convex combination of the leader states which is determined by the communication graph. It should be noted that our results can also regard the non-singular multi-agent systems’ containment control problem as a special case. Finally, simulation results corroborate the effectiveness of our analytical results.     

Containment control of heterogeneous fractional-order multi-agent systems

Fractional-order calculus has been studied deeply because many networked systems can only be described with fractional-order dynamics in complex environments. When different agents of networked systems show diverse individual features, fractional-order dynamics with heterogeneous characters will be used to illustrate the multi-agent systems (MAS). Based on the distinguishing behaviors of agents, a compounded fractional-order multi-agent systems(FOMAS) is presented with diverse dynamical equations. Suppose multiple leader agents existing in FOMAS, containment consensus control of FOMAS with directed weighted topologies is studied. By applying frequency domain analysis theory of the fractional-order operator, an upper bound of delays is obtained to ensure containment controls of heterogenous FOMAS with communication delays. The consensus results of delayed fractional-order dynamics in this paper can be expanded to the integer-order models. Finally, the results are verified by simulation examples.     

The effects of laser welding on heterogeneous immunoassay performance in a microfluidic cartridge

Sealing of a microfluidic cartridge is a challenge, because the cartridge commonly contains heat-sensitive biomolecules that must also be protected from contamination. In addition, the objective is usually to obtain a sealing method suitable for mass production. Laser welding is a rapid technique that can be accomplished with low unit costs. Even though the technique has been widely adopted in industry, the literature on its use in microfluidic applications is not large. This paper is the first to report the effects of laser welding on the performance of the heterogeneous immunoassay in a polystyrene microfluidic cartridge in which biomolecules are immobilized into the reaction surface of the cartridge before sealing. The paper compares the immunoassay performance of microfluidic cartridges that are sealed either with an adhesive tape or by use of laser transmission welding. The model analyte used is thyroid stimulating hormone (TSH). The results show that the concentration curves in the laser-welded cartridges are very close to the curves in the taped cartridges. This indicates, first, that laser welding does not cause any significant reduction in immunoassay performance, and second, that the polystyrene cover does not have significant effect on the signal levels. Interestingly, the coefficients of variance between parallel samples were lower in the laser-welded cartridges than in the taped cartridges.     

Mean-square consensus of heterogeneous multi-agent systems with communication noises

This paper addresses the mean-square consensus problems of continuous-time heterogeneous multi-agent systems with communication noises. First, in order to attenuate the communication noises, time-varying consensus gains are applied in the consensus algorithm. Then, by using the tools of algebraic graph theory and stochastic analysis, sufficient conditions for the mean-square consensus are given for the cases with and without a leader. Finally, simulations are provided to demonstrate the effectiveness of the proposed algorithms.     

Connectivity-preserving rendezvous of heterogeneous multi-agent systems under denial-of-Service attacks

This article investigates the rendezvous problem of heterogeneous multi-agent systems against Denial-of-Service attacks with preserving initial connectivity under a dynamic communication topology. The algorithm of resisting Denial-of-Service attack is first introduced to connectivity-preserving rendezvous problem of heterogeneous multi-agent systems. First of all, in order to observe the information of the leader, the distributed observers are designed to estimate the state of the leader with the communication network in the presence of Denial-of-Service attack by adaptive algorithm. Then, a switching system model is constructed by taking into account the influence of Denial-of-Service attacks. By means of the obtained model combined with a artificial potential function technique, the proposed distributed control algorithm allows all agents to accomplish rendezvous assignment with connectivity preservation as well as resisting Denial-of-Service attacks. Finally, detailed simulation validates the effectiveness of the proposed distributed observer and controller algorithm.     

Output consensus of heterogeneous linear systems with quantized information

In this paper, we design two distributed output consensus controllers for heterogeneous linear systems based on internal model principle and then study the quantization effect on the controllers when uniform quantizers are used in the communication channels. The first controller considers the general situation when the internal model state matrix of the system may be unstable and the communication graphs are strongly connected directed graphs. We prove that the bound of the consensus error is proportional to the quantizer parameter with a coefficient related to the size of the network and the property of the communication graphs. The second controller considers the situation when the internal model state matrix is neutrally stable and the communication graphs are undirected connected graphs. In this case, we derive a better bound of the consensus error which is proportional to the quantizer parameter and the coefficient is unrelated to the size of the network when the linear systems are homogeneous. Simulation examples are provided to illustrate the theoretical results.     

Questions as a factor in Web search strategy

This paper studies the influence of question-related variables (closed/open and predictable/unpredictable source) on Web users’ choices of search strategy (direct address, subject directory, and search engine) in the initial stage of a search. Subjects are 54 Finnish and American students with about 2.5 yr of Web searching. Data were gathered via a questionnaire asking for decisions for 16 questions of four types: closed/predictable source; closed/unpredictable source; open/predictable source; open/unpredictable source. The participants not only indicated a fairly high degree of familiarity with the initial search options and used different search strategies but also were influenced in their choice of an initial search strategy by question-related characteristics. Of the two question characteristics in the study, the most influential is the predictable/unpredictable source of the answer. The participants mentioned 24 different types of reasons for selecting the initial search strategy, which were grouped by their focus on questions, sources, and search strategy options. The reasons varied across question types. A model of choice behavior shows relationships among the initial question, the reasons, and the choice of initial search strategies.     

单点登录在数字校园异构系统集成中的应用

文章通过对数字校园系统集成,对数字校园的总体结构进行分析,阐述了将不同结构的系统集成在同一个平台下的基本方法,除了从多方面和角度给出了对单点登录（SSO）的全面分析,还讨论了如何将现有的应用和SSO服务结合起来,帮助应用架构师和系统分析人员从本质上认识单点登录。从而设计出符合数字校园需求的架构体系。     

Fault-tolerant control for a class of linear interconnected hyperbolic systems by boundary feedback

This paper considers a fault-tolerant control problem for a class of interconnected linear hyperbolic partial differential equation systems. Both subsystem faults and coupling faults are considered. Firstly, the well-posedness of the faulty system is analyzed by using semigroup theory. Secondly, for the fault-free case, a stabilizing boundary feedback control based on small-gain theorem is proposed. Consequently, in the presence of faults, fault recoverability conditions are established that maintain the stability of the faulty systems. The fault-tolerant control strategies are also provided. A heat exchanger example is taken to illustrate the effectiveness and practicality of the proposed methods.     

出口技术复杂度赶超对经济增长影响的实证分析——基于要素密集度异质性视角的非线性检验

基于2002-2008年省级层面十二大类(HS码)产品的出口数据,测度了28个省级区域劳动和资本密集型产业的出口技术复杂度赶超系数,进而运用门槛效应模型对赶超的经济增长效应进行了非线性检验,研究结果显示:首先出口技术复杂度赶超对经济增长的作用力呈现出明显的非线性;其次执行出口技术复杂度赶超策略不一定能促进本地经济增长,且我国劳动密集型产业出口技术复杂度赶超对经济增长的作用力存在显著的"收敛区间";最后东部地区资本密集型产业及东中部劳动密集型产业的出口技术复杂度赶超力度可进一步加强,而大力赶超的策略并不适合中西部地区资本密集型产业。     

Output formation-containment of coupled heterogeneous linear systems under intermittent communication

This paper investigates the output formation-containment problem of the coupled heterogeneous linear systems under intermittent communication. The systems considered in this paper are more general in the sense that each system, whether a leader or a follower, has different dimension and different dynamic. Besides, each system only communicates with its neighbors intermittently. Based on the intermittent information, both the state-feedback and the output-feedback distributed control protocols are designed and a criterion is derived to calculate the lower bound of the communication ratio. Furthermore, a heuristic algorithm based on the Fireworks Algorithm is developed to obtain an optimized communication ratio, which greatly reduces the communication burden. Finally, numerical examples are provided to demonstrate the effectiveness of the theoretical results.     

The heterogeneous effects of patent scope on licensing propensity

How does patent scope influence licensing propensity of inventions? Prior studies have often been confined to specific industries or settings, and their results have been mixed with studies showing a positive, a negative, or even no significant relationship. Also, while some have explored moderating factors that might influence the patent scope-licensing relationship, a systematic investigation of the heterogeneous effects of patent scope on licensing at the invention level has not been undertaken. This study combines a broad sample of publicly reported patent licensing agreements and a novel methodology that captures an exogenous variation in patent scope to re-investigate the relationship between patent scope and licensing and to explore key invention and inventor characteristics that could influence this relationship. The results show that narrowed patent scope leads to a substantial decline in licensing propensity of inventions and that the effect is stronger for high-quality, science-based, and novel inventions as well as for inventions generated by small inventors.     

The heterogeneous effects of environmental taxation on green technologies

This paper analyses the effectiveness of environmental taxation in stimulating the adoption of end-of-pipe and cleaner production technologies across manufacturing and mining firms between 2008 and 2014. We perform simple and categorical treatment matching of firms to study the heterogeneous effects of different taxation levels. We assess the effects between firms forced to pay environmental taxation (treated) and those that did not have to pay such taxes (controls), as well as between different levels of environmental taxation (small, medium, large). We find that low levels of environmental taxation are ineffective at stimulating green technology adoption. As the taxation level increases, so does the associated effect on green technology investment. Additionally, we find that even low levels of environmental taxation can be effective when combined with public financing. In this case, the effect is stronger than that of providing public financing alone.     

异构多核平台上基于任务划分和调度的性能评估方法

提出一种异构多核平台上的性能评估方法.该方法与多核任务的动态划分和调度算法相结合,可以获得给定任务集在不同硬件平台上的任务加速比.与此同时,针对不同层次的实时性需求,该算法可以给出硬件平台配置及任务划分方案.仿真实验和FPGA原型系统的测试数据表明,在任务之间存在依赖关系的情况下,该方法能够获得90%的精确度,在无依赖关系时,算法的精度为98.9%.     

Robust multi-tracking of heterogeneous multi-agent systems with uncertain nonlinearities and disturbances

A robust multi-tracking problem is solved for heterogeneous multi-agent systems with uncertain nonlinearities and disturbances. The nonlinear function satisfies a Lipschitz condition with a time-varying gain, the integral of which is bounded by a linear function. A distributed impulsive protocol is proposed, where the position data and velocity data of desired trajectories are needed only at sampling instants. Based on the system decomposition technique, the error dynamic system of achieving multi-tracking is decomposed into two impulsive dynamic systems with vanishing perturbation and nonvanishing perturbation, respectively. Constructing a nominal model, then the multi-tracking problem is converted into the stability of impulsive dynamic system with nonvanishing perturbation under some conditions. It is proved that the proposed impulsive protocol is robust enough to solve the multi-tracking problem. Numerical examples are presented to illustrate the effectiveness of our theoretical results.