Hot Topic Propagation Model and Opinion Leader Identifying Model in Microblog Network

As the network technique is fast developing, the microblog has been a significant carrier representing the social public opinions. Therefore, it is important to investigate the propagation characteristics of the topics and to unearth the opinion leaders in Micro-blog network. The propagation status of the hot topics in the Micro-blog is influenced by the authority of the participating individuals. We build a time-varying model with the variational external field strength to simulate the topic propagation process. This model also fits for the multimodal events. The opinion leaders are important individuals who remarkably influence the topic discussions in its propagation process. They can help to guide the healthy development of public opinion. We build an AHP model based on the influence, the support, and the activity of a node, as well as a microblog-rank algorithm based on the weighted undirected network, to unearth and analyze the opinion leaders’ characteristics. The experiments in the data, collected from the Sina Micro-blog from October 2012 to November 2012 and from January 2013 to February 2013, show that our models predict the trend of hot topic efficiently and the opinion leaders we found are reasonable

Non-degenerate colorings in the Brook's Theorem

Let $c\geq 2$ and $p\geq c$ be two integers. We will call a proper coloring of the graph $G$ a \textit{$(c,p)$-nondegenerate}, if for any vertex of $G$ with degree at least $p$ there are at least $c$ vertices of different colors adjacent to it. In our work we prove the following result, which generalizes Brook's Theorem. Let $D\geq 3$ and $G$ be a graph without cliques on $D+1$ vertices and the degree of any vertex in this graph is not greater than $D$. Then for every integer $c\geq 2$ there is a proper $(c,p)$-nondegenerate vertex $D$-coloring of $G$, where $p=(c^3+8c^2+19c+6)(c+1).$ During the primary proof, some interesting corollaries are derived.Comment: 18 pages, 10 figure

A dynamic aspiration-based interaction strategy blocks the spread of defections in social dilemma

Considering the time-varying selection criterions of neighbors, we propose a dynamic interaction strategy to determine interactive neighbors based on aspiration payoffs. Under this strategy, interactions decide the aspiration payoffs and interactive payoffs, after that, the group is divided into high-payoff and low-payoff subgroups. And individuals in the same subgroup constitute the interactions in turn, which indicates an internal feedback mechanism. Based on the spatial prisoner's dilemma game, simulations show that the introduction of this interaction strategy successfully delays the extinction of cooperators. And cooperation is enhanced at appropriate aspiration levels but suppressed with high temptations. Moreover, under an appropriate aspiration level, high-payoff cooperators are able to expand the scale of cooperator clusters and low-payoff cooperators maintain the stability of cooperative behaviors by both forming an isolation belt around cooperator clusters and promoting the appearance of high-payoff cooperators, which blocks the invasion of defectors and leads to a state of complete cooperation

Evolution of cooperation in prisoner's dilemma game under the coupling of aspiration and imitation rules

Considering the important roles played by aspiration and imitation rules, we explore how cooperation evolves in the spatial prisoner's dilemma game. In detail, the strategy updating rule couples the inner aspiration payoff and the external neighborâs payoff through the parameter α. Intriguingly, we find that there exists an optimal value of α leading to the highest density of cooperators for each aspiration level A. By analyzing the dynamical strategy changes of the system, we find that an optimal α helps individuals form cooperator clusters and curbs the further spread of high-payoff defectors, and thus improves the density of cooperators. Moreover, when $0.1\leq A\leq0.5$ , the optimal value of α, which leads to the highest density of cooperators, decreases with A, the optimal range of α gradually expands and the highest cooperation level is on the rise

On 3-connected hamiltonian line graphs

AbstractThomassen conjectured that every 4-connected line graph is hamiltonian. It has been proved that every 4-connected line graph of a claw-free graph, or an almost claw-free graph, or a quasi-claw-free graph, is hamiltonian. In 1998, Ainouche et al. [2] introduced the class of DCT graphs, which properly contains both the almost claw-free graphs and the quasi-claw-free graphs. Recently, Broersma and Vumar (2009) [5] found another family of graphs, called P3D graphs, which properly contain all quasi-claw-free graphs. In this paper, we investigate the hamiltonicity of 3-connected line graphs of DCT graphs and P3D graphs, and prove that if G is a DCT graph or a P3D graph with κ(L(G))≥3 and if L(G) does not have an independent vertex 3-cut, then L(G) is hamiltonian. Consequently, every 4-connected line graph of a DCT graph or a P3D graph is hamiltonian

A Solution to Reconstruct Cross-Cut Shredded Text Documents Based on Character Recognition and Genetic Algorithm

The reconstruction of destroyed paper documents is of more interest during the last years. This topic is relevant to the fields of forensics, investigative sciences, and archeology. Previous research and analysis on the reconstruction of cross-cut shredded text document (RCCSTD) are mainly based on the likelihood and the traditional heuristic algorithm. In this paper, a feature-matching algorithm based on the character recognition via establishing the database of the letters is presented, reconstructing the shredded document by row clustering, intrarow splicing, and interrow splicing. Row clustering is executed through the clustering algorithm according to the clustering vectors of the fragments. Intrarow splicing regarded as the travelling salesman problem is solved by the improved genetic algorithm. Finally, the document is reconstructed by the interrow splicing according to the line spacing and the proximity of the fragments. Computational experiments suggest that the presented algorithm is of high precision and efficiency, and that the algorithm may be useful for the different size of cross-cut shredded text document