Predictive protocol of flocks with small-world connection pattern

By introducing a predictive mechanism with small-world connections, we propose a new motion protocol for self-driven flocks. The small-world connections are implemented by randomly adding long-range interactions from the leader to a few distant agents, namely pseudo-leaders. The leader can directly affect the pseudo-leaders, thereby influencing all the other agents through them efficiently. Moreover, these pseudo-leaders are able to predict the leader's motion several steps ahead and use this information in decision making towards coherent flocking with more stable formation. It is shown that drastic improvement can be achieved in terms of both the consensus performance and the communication cost. From the industrial engineering point of view, the current protocol allows for a significant improvement in the cohesion and rigidity of the formation at a fairly low cost of adding a few long-range links embedded with predictive capabilities. Significantly, this work uncovers an important feature of flocks that predictive capability and long-range links can compensate for the insufficiency of each other. These conclusions are valid for both the attractive/repulsive swarm model and the Vicsek model.Comment: 10 pages, 12 figure

Pseudogap and Fermi-arc Evolution in the Phase-fluctuation Scenario

Pseudogap phenomena and the formation of Fermi arcs in underdoped cuprates are numerically studied in the presence of phase fluctuations that are simulated by an XY model. Most importantly the spectral function for each Monte Carlo sample is calculated directly and efficiently by the Chebyshev polynomials without having to diagonalize the fermion Hamiltonian, which enables us to handle a system large enough to achieve sufficient momentum/energy resolution. We find that the momentum dependence of the energy gap is identical to that of a pure d-wave superconductor well below the KT-transition temperature ($T_{KT}$), while displays an upturn deviation from $\cos k_x - \cos k_y$ with increasing temperature. An abrupt onset of the Fermi arcs is observed above $T_{KT}$ and the arc length exhibits a similar temperature dependence to the thermally activated vortex excitations.Comment: 5 pages, 4 figure

Microscopic study of induced fission dynamics of 226^{226}Th with covariant energy density functionals

Static and dynamic aspects of the fission process of $^{226}$Th are analyzed in a self-consistent framework based on relativistic energy density functionals. Constrained relativistic mean-field (RMF) calculations in the collective space of axially symmetric quadrupole and octupole deformations, based on the energy density functional PC-PK1 and a $\delta$-force pairing, are performed to determine the potential energy surface of the fissioning nucleus, the scission line, the single-nucleon wave functions, energies and occupation probabilities, as functions of deformation parameters. Induced fission dynamics is described using the time-dependent generator coordinate method in the Gaussian overlap approximation. A collective Schr\"odinger equation, determined entirely by the microscopic single-nucleon degrees of freedom, propagates adiabatically in time the initial wave packet built by boosting the ground-state solution of the collective Hamiltonian for $^{226}$Th. The position of the scission line and the microscopic input for the collective Hamiltonian are analyzed as functions of the strength of the pairing interaction. The effect of static pairing correlations on the pre-neutron emission charge yields and total kinetic energy of fission fragments is examined in comparison with available data, and the distribution of fission fragments is analyzed for different values of the initial excitation energy.Comment: 25 pages, 14 figures, accepted for publication in Phys. Rev.

Institutions and FDI location choice: The role of cultural distances

Using an extensive data set on foreign invested enterprises (FIEs) in the Chinese mainland, we compare the sensitivities of the location choice of foreign direct investment (FDI) from six major source countries/areas (Hong Kong, Taiwan, US, EU, Japan and Korea) toward the variation in the strength of economic institutions across China's regions. It is found that FIEs from the source countries/areas that are culturally more remote from China often exhibit a stronger aversion to regions with weaker economic institutions. Moreover, this pattern is often more salient when FDI takes the form of fully-owned enterprises (FOEs) than when it takes the form of joint ventures (JVs). © 2011 Elsevier Inc..preprin

An empirical study on the access to bank loans by private enterprises in China

本文利用对我国私营企业的调查数据研究影响私营企业获得银行贷款难易程度的因素。我们发现,私营企业在财产权受到侵蚀和面临政策歧视的情况下获得银行贷款比较困难,此外,私营企业主对私有财产权的自我保护有助于私营企业获得银行贷款。我们还发现,在借贷双方的信息不对称和借款方道德风险问题得到较好解决的情况下,私营企业比较容易得到贷款。postprin

Exporting behavior of foreign affiliates: Theory and evidence

Firms have increasingly conducted different stages of production in different countries. In particular, they may set up operations in low-cost countries (those operations are referred to as foreign affiliates in those countries) either as platforms for export or serving the growing markets there. What is the exporting behavior of foreign affiliates? In this paper, using data from China, we find that among foreign affiliates exporters are less productive than non-exporters. We then offer a theoretical explanation by incorporating into the standard firm heterogeneity model the possibility that firms could have different stages of production in different countries. © 2010 Elsevier B.V.postprin

Why do firms conduct bi-sourcing?

In acquiring the same intermediate inputs, a firm often conducts bi-sourcing, i.e., simultaneously buying from external suppliers and self-producing in an internal manufacturer. We show that the firm achieves a better bargaining position in bisourcing than in outsourcing through cross threat effect, which enhances profitability. © 2006 Elsevier B.V. All rights reserved.preprin