Generating Aspect-oriented Multi-document Summarization with Event-Aspect Model

In this paper, we propose a novel approach to automatic generation of aspect-oriented summaries from multiple documents. We first develop an event-aspect LDA model to cluster sentences into aspects. We then use extended LexRank algorithm to rank the sentences in each cluster. We use Integer Linear Programming for sentence selection. Key features of our method include automatic grouping of semantically related sentences and sentence ranking based on extension of random walk model. Also, we implement a new sentence compression algorithm which use dependency tree instead of parser tree. We compare our method with four baseline methods. Quantitative evaluation based on Rouge metric demonstrates the effectiveness and advantages of our method.

Different contributions to space weather and space climate from different big solar active regions

The purpose of this paper is to show that large active regions (ARs) with different magnetic configurations have different contributions to short-term and long-term variations of the Sun. As a case study, the complex $\delta$-type AR 12673 and the simple $\beta$-type AR 12674 are investigated in detail. Since the axial dipole moment at cycle minimum determines the amplitude of the subsequent cycle and space climate, we have assimilated the individual observed magnetic configurations of these two ARs into a surface flux transport model to compare their contributions to the axial dipole moment $D$. We find that AR 12673 has a significant effect on $D$ at the end of the cycle, making it weaker because of the abnormal and complicated magnetic polarities. An initial strongly positive $D$ ends up with a strongly negative value. The flare-poor AR 12674 has a greater contribution to the long-term axial dipole moment than the flare-rich AR 12673. We then carry out a statistical analysis of ARs larger than 800 $\mu$Hem from 1976 to 2017. We use the flare index FI and define an axial dipole moment index DI to quantify the effects of each AR on space weather and space climate, respectively. Whereas the FI has a strong dependence on the magnetic configuration, the DI shows no such dependence. The DI is mainly determined by the latitudinal location and the latitudinal separation of the positive and negative magnetic fluxes of the ARs. Simple ARs have the same possibility as complex ARs to produce big DI values affecting space climate.Comment: 18 pages, 8 figures, Accepted for publication in the Astrophysical Journa

Does the Legal System Affect the Cost of External Financing? Evidence from IPO Underpricing of Foreign Firms Listed in U.S. Stock Markets

To study the effect of the legal system on the cost of external financing, we examine the degree of underpricing of the IPOs by foreign companies listed in U.S. We find that firms from highly corrupted countries have larger IPO underpricing. The quality of the home-country public law enforcement reduces the degree of IPO underpricing. In particular, the criminal sanction for violations of securities laws is the most significant factor in reducing underpricing. The evidence shows that even when a non-U.S. firm meets sophisticated U.S. regulations and goes public in a U.S. exchange, the degree of underpricing is still influenced by the legal and judicial system in the home country. Following La Porta et al. (2000a), we provide evidence against the functional convergence hypothesis (Coffee, 1999 and 2002)

Top Hypercharge

We propose a top hypercharge model with gauge symmetry SU(3)_C x SU(2)_L x U(1)_1 x U(1)_2 where the first two families of the Standard Model (SM) fermions are charged under U(1)_1 while the third family is charged under U(1)_2. The U(1)_1 x U(1)_2 gauge symmetry is broken down to the U(1)_Y gauge symmetry, when a SM singlet Higgs field acquires a vacuum expectation value. We consider the electroweak constraints, and compare the fit to experimental observables to that of the SM. We study the quark CKM mixing between the first two families and the third family, the neutrino masses and mixing, the flavour changing neutral current effects in meson mixing and decays, the Z' discovery potential at the Large Hadron Collider, the dark matter with a gauged Z_2 symmetry, and the Higgs boson masses.Comment: 17 pages and 4 figure

Large-Gap Quantum Anomalous Hall Insulators in AATiXX Class

We theoretically propose that the monolayer $A$Ti$X$ family (KTiSb, KTiBi, RbTiSb, SrTiSn) are potential candidates for large-gap quantum anomalous Hall insulators with high Chern number $\mathcal{C}=2$. Both of the topology and magnetism in these materials are from $3d$-orbitals of Ti. We construct the tight-binding model with symmetry analysis to reveal the origin of topology. Remarkably, quite different from the conventional $s$-$d$ band inversion, here the topological band inversion within $3d$ orbitals is due to the crystal field and electron hopping, while spin-orbit coupling only trivially gaps out the Dirac cone at Fermi level. The general physics from the $3d$ orbitals here applies to a large class of transition metal compounds with the space group $P4/nmm$ or $P$-$42m$ and their subgroups.Comment: 6 pages, 4 figure

The Research on Competitive Abilities for Sustainable Development of Small and Medium-sized Textile Enterprises in Shandong Province

Under the condition of market competition, the success and the failure of the enterprise management is normally regarded as the result of “superior winning while inferior out”. Yet for the community of theorists and entrepreneurs, what are the reasons leading to the enterprise bankruptcy or successful are important research topics. Among the small and medium-sized enterprises in China, most are loose and innovating slowly in their business management. The lower competitive ability has become the serious barrier for their sustainable development. Comprehensive analysis are made on the positive factors and adverse factors affecting sustainable development of small and medium-sized textile enterprises of Shandong Province according to on-the-spot investigations. How to gain and maintain the continued survival and development ability of the enterprises, and how to enhance competitive ability and realize the sustainable development are analyzed. And three kinds of development strategies are put forward