Rank-based deactivation model for networks with age

We study the impact of age on network evolution which couples addition of new nodes and deactivation of old ones. During evolution, each node experiences two stages: active and inactive. The transition from the active state to the inactive one is based on the rank of the node. In this paper, we adopt age as a criterion of ranking, and propose two deactivation models that generalize previous research. In model A, the older active node possesses the higher rank, whereas in model B, the younger active node takes the higher rank. We make a comparative study between the two models through the node-degree distribution.     

Choosing effective controlled nodes for scale-free network synchronization

Previous studies concerning pinning control of complex-network synchronization have very often demonstrated that in an unweighted symmetrical scale-free network, controlling the high-degree nodes is more efficient than controlling randomly chosen ones; due to the heterogeneity of the node-degree or edge-connection distribution of the scale-free network, small-degree nodes have relatively high probabilities of being chosen at random but their control has less influence on the other nodes through the network. This raises the question of whether or not controlling the high-degree nodes is always better than controlling the small ones in scale-free networks. Our answer to this is yes and no. In this study, we carry out extensive numerical simulations to show that in an unweighted symmetrical Barabasi-Albert scale-free network, when the portion of controlled nodes is relatively large, controlling the small nodes becomes better than controlling the big nodes and controlling randomly chosen nodes has approximately the same effect as controlling the big ones. However, we also show that for normalized weighted scale-free networks, controlling the big nodes is in fact always better than controlling the small ones.     

回归的能源有效网络大数据流汇聚算法研究

为了降低传感器网络数据流汇聚时的能源消耗,提出了一种基于回归的能源有效数据流汇聚算法。首先,将传感器节点分为活跃节点和能源有效节点。然后,以活跃节点为中心点将所有节点进行聚类,并应用回归方法通过活跃节点的数据流对能源有效节点的数据进行预测。接下来,通过节点预测值的累积误差不断修正活跃节点集。最后,应用活跃节点的数据流信息对能源有效节点的数据进行预测。实验表明,本文提出的算法与其它相关算法相比具有更好的预测准确性。     

甲状腺癌转移性淋巴结的红外光谱研究

联合运用衰减全反射(attenuated total reflectance,ATR)探头与FTIR光谱仪,测定了新鲜离体的甲状腺癌转移性颈部淋巴结20枚和非转移性淋巴结69枚的FTIR光谱,比较两组光谱13个谱带的峰位及相对峰强等28个指标,找出甲状腺癌转移性淋巴结光谱的特征。与非转移性淋巴结相比,转移性淋巴结光谱中与蛋白、脂质、糖类、核酸相关的谱带均发生了明显的变化,具体如下：(1)与蛋白质相关的谱带的相对峰强I_{3 280}/I1 460(P=0.029),I_{1 640}/I_{1 460}(P=0.019),I_{1 546}/I_{1 460}(P=0.004)均显著升高;(2)脂类相关的相对峰强I_{1 743}/I_{1 460}显著降低(P=0.026),而I_{1 400}/I_{14 60}则明显增高(P=0.001);(3)与糖类相关的1 165与1 120 cm-1处峰位P_{1 165}(P=0.019),P_{1 120}(P=0.000)发生明显蓝移(向高波数移动),相对峰强I1 165/I_{1 460}显著降低(P=0.006);(4)与核酸相关的1 085 cm-1处峰位P_{1 085}发生明显地红移(向低波数移动)(P=0.029);(5)其他指认未明的谱带的相对峰强I_{1 303}/I_{1 460}(P=0.008),I_{1 303}/I1 240(P=0.039)均明显升高。与非转移性淋巴结光谱相比较,甲癌转移的淋巴结光谱在多个谱带的峰位或相对峰强方面存在显著的差异。FTIR可应用于术中甲状腺癌转移性淋巴结的探测。     

Interband proximity effect and nodes of superconducting gap in Sr2RuO4

The power-law temperature dependences of the specific heat, the nuclear relaxation rate, and the thermal conductivity suggest the presence of line nodes in the superconducting gap of Sr2RuO4. These recent experimental observations contradict the scenario of a nodeless (k(x)+ik(y))-type superconducting order parameter. We propose that interaction of superconducting order parameters on different sheets of the Fermi surface is a key to understanding the above discrepancy. A full gap exists in the active band, which drives the superconducting instability, while line nodes develop in passive bands by the interband proximity effect.     

A Topological Glass

We propose and study a model with glassy behavior. The state space of the model is given by all triangulations of a sphere with n nodes, half of which are red and half are blue. Red nodes want to have 5 neighbors while blue ones want 7. Energies of nodes with other numbers of neighbors are supposed to be positive. The dynamics is that of flipping the diagonal of two adjacent triangles, with a temperature dependent probability. We show that this system has an approach to a steady state which is exponentially slow, and show that the stationary state is unordered. We also study the local energy landscape and show that it has the hierarchical structure known from spin glasses. Finally, we show that the evolution can be described as that of a rarefied gas with spontaneous generation of particles and annihilating collisions.     

Synchronization criterion for Lur'e type complex dynamical networks with time-varying delay

In this Letter, the synchronization problem for a class of complex dynamical networks in which every identical node is a Lur'e system with time-varying delay is considered. A delay-dependent synchronization criterion is derived for the synchronization of complex dynamical network that represented by Lur'e system with sector restricted nonlinearities. The derived criterion is a sufficient condition for absolute stability of error dynamics between the each nodes and the isolated node. Using a convex representation of the nonlinearity for error dynamics, the stability condition based on the discretized Lyapunov-Krasovskii functional is obtained via LMI formulation. The proposed delay-dependent synchronization criterion is less conservative than the existing ones. The effectiveness of our work is verified through numerical examples.     

Noise enhanced activity in a complex network

We consider the influence of local noise on a generalized network of populations having positive and negative feedbacks. The population dynamics at the nodes is nonlinear, typically chaotic, and allows cessation of activity if the population falls below a threshold value. We investigate the global stability of this large interactive system, as indicated by the average number of nodal populations that manage to remain active. Our central result is that the probability of obtaining active nodes in this network is significantly enhanced under fluctuations. Further, we find a sharp transition in the number of active nodes as noise strength is varied, along with clearly evident scaling behaviour near the critical noise strength. Lastly, we also observe noise induced temporal coherence in the active sub-network, namely, there is an enhancement in synchrony among the nodes at an intermediate noise strength.     

Adaptive pinning synchronization in fractional-order complex dynamical networks

Synchronization of general complex dynamical networks with fractional-order dynamical nodes is addressed in this paper. Based on the stability theory of fractional-order differential systems and adaptive pinning control, some sufficient local asymptotical synchronization criteria and global asymptotical ones are derived respectively, which succeed in solving the problem about how many nodes are need to be controlled and how much coupling strength should be applied to ensure the synchronization of the entire fractional-order networks. The obtained results are more general and effective than those reported. Moreover, the coupling-configuration matrices and the inner-coupling matrices are not assumed to be symmetric and irreducible. Finally, a numerical simulation is presented to demonstrate the validity and feasibility of the proposed synchronization criteria.     

Current-mode current-tunable four-phase quadrature oscillator

A current-mode current-tunable four-phase quadrature oscillator (QO) using current differencing transconductance amplifiers (CDTA) is presented in this paper. The proposed QO consists of three CDTAs and two grounded capacitors, which can provide four quadrature current outputs at high impedance nodes. The proposed QO has the advantages of electronically and independently control of oscillation condition and oscillation frequency. Moreover, the active and passive sensitivities of the QO are low. Cadence IC Design Tools 5.1.41 post-layout simulation results are included to confirm the theory.     

含有源非线性负阻二端网络电路系统的动力学行为

本文对一个含有源非线性负阻二端网络的RLC串联电路系统进行数值研究,发现该系统在不同的参数范围内分别出现倍周期分岔序列、混沌带的反序列以及阵发混沌现象,将这些结果与实验结果比较符合得很好。 关键词：     

推荐重要节点部署防御策略的优化模型

当前网络安全防御策略集中部署于高连接度节点主要有2个方面的不足: 一是高连接度节点在很多场合中并不是网络通信的骨干节点; 二是该类节点对信息的转发和传播并非总是最有效的.针对以上传统部署策略的不足, 改进了恶意病毒程序传播的离散扩散模型并采用中间路径跳数来衡量网络节点的重要程度, 提出了基于介数中心控制力和接近中心控制力模型的重要节点优先推荐部署技术.实验结果显示具有高介数中心控制力和低接近中心控制力的节点相对于传统的高连接度节点无论在无标度网络还是小世界网络均能够对恶意病毒程序的疫情扩散和早期传播速度起到更加有效的抑制作用, 同时验证了网络分簇聚类行为产生的簇团特性也将对恶意程序的传播起到一定的负面影响.     

New geometrical frameworks for classical impulsive mechanics

A new context is introduced to give a formal geometric environment for the study of impulsive mechanics of systems with finite number of degrees of freedom. The new structures embody the usual ones of analytical mechanics such as tangent bundles for time independent systems and jet-bundles for time dependent ones. They allow a causally consistent definition of active impulse acting on the systems and a clear geometric view of the equations of motion.     

Randomly layered active medium as a broadband amplifier

A flat-layered active medium in which two types of layers with different refractive indices alternate is considered. The thickness of a layer is assumed to be random and large as compared to the wavelength of propagating radiation. A wave propagating along the normal to the layers in such a medium is exponentially enhanced over lengths of the order of many layer thicknesses. In contrast to the familiar case of a periodic flat-layered active medium, waves with any (not necessarily definite resonant) frequency are amplified identically in a wide frequency range. By way of an example, convective instability of space-charge waves in a flow of charged particles moving through a randomly layered medium is considered. The predicted effect can be regarded as an analogue of Anderson’s localization, when increasing solutions rather than exponentially ecreasing ones are selected in view of the activity of the medium.     

Epidemic threshold and immunization on generalized networks

The susceptible–infected–susceptible (SIS) model is widely adopted in the studies of epidemic dynamics. When it is applied on contact networks, these networks mostly consist of nodes connected by undirected and unweighted edges following certain statistical properties, whereas in this article we consider the threshold and immunization problem for the SIS model on generalized networks that may contain different kinds of nodes and edges which are very possible in the real situation. We proved that an epidemic will become extinct if and only if the spectral radius of the corresponding parameterized adjacent matrix (PAM) is smaller than 1. Based on this result, we can evaluate the efficiency of immune strategies and take several prevailing ones as examples. In addition, we also develop methods that can precisely find the optimal immune strategies for networks with the given PAM.     

Modeling the effects of social impact on epidemic spreading in complex networks

We investigate by mean-field analysis and extensive simulations the effects of social impact on epidemic spreading in various typical networks with two types of nodes: active nodes and passive nodes, of which the behavior patterns are modeled according to the social impact theory. In this study, nodes are not only the media to spread the virus, but also disseminate their opinions on the virus—whether there is a need for certain self-protection measures to be taken to reduce the risk of being infected. Our results indicate that the interaction between epidemic spreading and opinion dynamics can have significant influences on the spreading of infectious diseases and related applications, such as the implementation of prevention and control measures against the infectious diseases.     

An adaptive reservation scheme for optical network

In this paper, the various Optical Burst Switching (OBS) reservation schemes have been examined in order to reduce data loss caused by either channel scheduling or resources. A novel multi-service OBS edge node with synchronized bandwidth reservation mechanism (SRM) has been proposed, which enables high-speed network transport nodes to dynamically reserve bandwidth needed for active data burst flows. The performance of the proposed mechanism is evaluated by means of NS-2 simulation. The results show that the packet delay is kept within the constraint for each traffic flow and the performance metrics such as burst loss rate, throughput and fairness are remarkably improved.     

Origin of the pseudospin symmetry in the relativistic formalism

The grounds on which the nuclear pseudospin symmetry (PSS) is supposed to be based are analysed within the relativistic mean-field framework. A connection between the mechanisms responsible for the spin-orbit and pseudospin-orbit splittings is shown. The nature of the PSS is investigated through an extended Dirac equation which allows a generalization of the PSS breaking term. It is shown that the PSS breaking in real nuclei can be explained as a result of a non-perturbative transformation from non-physical solutions of the Dirac equation, which satisfy exactly the PSS, to the physical ones. The PSS breaking term produces important, though qualitatively similar, effects on both states of a pseudospin-orbit doublet. The similarity of these effects increases with the number of nodes of the small component of the Dirac spinor of these states.Received: 28 April 2003, Revised: 30 October 2003, Published online: 18 June 2004PACS: 24.10.Jv Relativistic models - 21.60.Cs Shell model - 21.10.Pc Single-particle levels and strength functions - 24.80. + y Nuclear tests of fundamental interactions and symmetries     

Evolutionary model on market ecology of investors and investments

The interactions between investors and investments are of significant importance to understand the dynamics of financial markets. An evolutionary model is proposed to investigate the dynamic behaviors of investors and investments in a market ecology. The investors are divided into two groups, active ones and passive ones, distinguished by different selection capabilities based on the partial information, while the investments are simply categorized as good ones and bad ones. Without external influence, the system consisting of both investors and investments can self-organize to a quasi-stationary state according to their own strategies associating with the gains of market information. The model suggests that the partial information asymmetry of investors and various qualities of investments commonly give rise to a diverse dynamic behavior of the system by quantifying the fraction of active investors and of good investment at the quasi-stationary state.     

WDM网络中基于多核心的组播路由算法

提出了一种WDM网络中组播的分布式路由算法。该算法是一种基于核心树的算法,其关键是找到一个核心节点集,使得以该核心节点集为树根、包含组中所有节点的树满足延迟时限的要求,同时使树的成本尽量小。算法首先根据目的节点确定组中的核心节点集,并生成核心节点内部的稳定树;然后以核心节点集为树根构造包含所有目的节点的组播核心树。由于采用了分布式的方法建立核心树,并且采用的是多个核心,所以在一定程度上减少了建立组播树所需要的时间,并且有效地解决了系统在核心处的瓶颈问题。