arXiv subjects

Yulin Zhao

Publications and source records attributed to Yulin Zhao.

22 records · Page 2Linked to original sources

arXiv2014

Which factor dominates the industry evolution? A synergy analysis based on China's ICT industry

Industry evolution caused by various reasons, among which technology progress driving industry development has been approved, but with the new trend of industry convergence, inter-industry convergence also plays an increasing important role. This paper plans to probe the industry synergetic evolution mechanism based on industry convergence and technology progress. Firstly, we use self-organization method and Haken Model to establish synergetic evolution equations, select technology progress and industry convergence as the key variables of industry evolution system; then use patent licensing data of china's listed ICT companies to measure industry convergence rate and apply DEA Malmquist index method to calculate technology progress level; furthermore apply simultaneous equation estimation method to investigate the synergetic industry evolution process. From 2002 to 2012, China's ICT industry develops rapidly; it has the most obvious convergence and powerful technology progress compared with other industries. We choose china's listed ICT industry to make empirical analysis. Our main findings are: a) technology progress is the order parameter which dominates industry system evolution. Moreover, industry convergence is the control parameter which is influenced by technology progress; b) Development of technology progress is the core factor for causing evolution of industry system, and industry convergence is the outcome of technology progress; c) Especially, it is important that the dominated role of technology progress will be sustained, even though in the environment of convergence, companies also need focus on self-innovation, rather than only adapt to the new industry evolution trend.

physics.soc-ph↗

arXiv2011

On the structural stability of planar quasihomogeneous polynomial vector fields

Denote by $H_{pqm}$ the space of all planar $(p,q)$-quasihomogeneous vector fields of degree $m$ endowed with the coefficient topology. In this paper we characterize the set $Ω_{pqm}$ of the vector fields in $H_{pqm}$ that are structurally stable with respect to perturbations in $H_{pqm}$, and determine the exact number of the topological equivalence classes in $Ω_{pqm}$. The characterisation is applied to give an extension of the Hartman-Grobmann Theorem for such family of planar polynomial vector fields. It follows from the main result in this paper that, for a given $X \in H_{pqm}$ we give a explicit method to decide whether it is structurally stable with respect to perturbation in $H_{pqm}$ before finding the vector field induced by $X$ in the Poincaré-Lyapunov sphere. This work is an extension and an improvement of the Llibre-Perez-Rodriguez's paper \cite{LRR}, where the homogeneous case was considered. More precisely, if both $p$ and $q$ are odd, the main results of this paper are similar to those of the Llibre-Perez-Rodriguez's paper; if either $p$ or $q$ is odd while the other is even, we present some results which do not appear in the above mentioned paper. For example, one of the interesting results is that there may be triples $(p,q,m)$ such that $H_{pqm}\not=\emptyset$ but $Ω_{pqm}=\emptyset$, which does not occur in the homogeneous case.

math.CA↗

arXiv2011

Limit cycles for planar semi-quasi-homogeneous polynomial vector fields

This paper is concerned with the limit cycles for planar semi-quasi-homogeneous polynomial systems. We give some explicit criteria for the nonexistence and existence of periodic orbits. Let $N=N(p,q,m,n)$ be the maximum number of limit cycles of such system. A lower bound is given for $N=N(p,q,m,n)$. The cyclicity and center problem are studied for some subfamilies of semi-quasi-homogeneous polynomial systems. Our results generalize those obtained for polynomial semi-homogeneous systems.

math.CA↗

arXiv2010

On the number of limit cycles in quadratic perturbations of quadratic codimension four centers

This paper is concerned with the bifurcation of limit cycles in general quadratic perturbations of quadratic codimension-four centers $Q_4$. Gavrilov and Iliev set an upper bound of {\it eight} for the number of limit cycles produced from the period annulus around the center. Based on Gavrilov-Iliev's proof, we prove in this paper that the perturbed system has at most five limit cycles which emerge from the period annulus around the center. We also show that there exists a perturbed system with three limit cycles produced by the period annulus of $Q_4$.

math.DS↗