Extracting Noun Phrases from Large-Scale Texts: A Hybrid Approach and Its Automatic Evaluation

To acquire noun phrases from running texts is useful for many applications, such as word grouping,terminology indexing, etc. The reported literatures adopt pure probabilistic approach, or pure rule-based noun phrases grammar to tackle this problem. In this paper, we apply a probabilistic chunker to deciding the implicit boundaries of constituents and utilize the linguistic knowledge to extract the noun phrases by a finite state mechanism. The test texts are SUSANNE Corpus and the results are evaluated by comparing the parse field of SUSANNE Corpus automatically. The results of this preliminary experiment are encouraging.Comment: 8 pages, Postscript file, Unix compressed, uuencode

Second-order accurate genuine BGK schemes for the ultra-relativistic flow simulations

This paper presents second-order accurate genuine BGK (Bhatnagar-Gross-Krook) schemes in the framework of finite volume method for the ultra-relativistic flows. Different from the existing kinetic flux-vector splitting (KFVS) or BGK-type schemes for the ultra-relativistic Euler equations, the present genuine BGK schemes are derived from the analytical solution of the Anderson-Witting model, which is given for the first time and includes the "genuine" particle collisions in the gas transport process. The BGK schemes for the ultra-relativistic viscous flows are also developed and two examples of ultra-relativistic viscous flow are designed. Several 1D and 2D numerical experiments are conducted to demonstrate that the proposed BGK schemes not only are accurate and stable in simulating ultra-relativistic inviscid and viscous flows, but also have higher resolution at the contact discontinuity than the KFVS or BGK-type schemes.Comment: 41 pages, 13 figure

Monetary Policy, Term Structure and Asset Return: Comparing REIT, Housing and Stock

This paper confirms that a regime-switching model out-performs a linear VAR model in terms of understanding the system dynamics of asset returns. Impulse responses of REIT returns to either the federal funds rate or the interest rate spread are much larger initially but less persistent. Furthermore, the term structure acts as an amplifier of the impulse response for REIT return, a stabilizer for the housing counterpart under some regime, and, perhaps surprisingly, almost no role for the stock return. In contrast, GDP growth has very marginal effect in the impulse response for all assets.monetary policy; yield curve; REITs; house prices; Markov Regime Switching

In the Shadow of the United States: The International Transmission Effect of Asset Returns

We examine how the fluctuations in financial and housing markets in U.S. affect the asset returns and GDP in Hong Kong. In contrast to the results from linear specifications, which concludes that the U.S. and Hong Kong are virtually delinked in terms of the asset markets, our regime-switching models indicate that the unexpected shock of US stock returns, followed by the TED spread, has the most significant effect on HK asset returns and GDP, typically in the regime with high return and low volatility. For the in-sample one-step-ahead forecasting, US Term spread stands out to be the best predictor.currency board, fixed nominal exchange rate, international transmission mechanism, hierarchical Markov regime-switching model, vector autoregressive model

Unified Formalism for calculating Polarization, Magnetization, and more in a Periodic Insulator

In this paper, we propose a unified formalism, using Green's functions, to integrate out the electrons in an insulator under uniform electromagnetic fields. We derive a perturbative formula for the Green's function in the presence of uniform magnetic or electric fields. Applying the formula, we derive the formula for the polarization, the orbital magnetization, and the orbital magneto-polarizability, without assuming time reversal symmetry. Specifically, we realize that the terms linear in the electric field can only be expressed in terms of the Green's functions in one extra dimension. This observation directly leads to the result that the coefficient of the $\theta$ term in any dimensions is given by a Wess-Zumino-Witten-type term, integrated in the extended space, interpolating between the original physical Brillouin zone and a trivial system, with the group element replaced by the Green's function. This generalizes an earlier result for the case of time reversal invariance [see Z. Wang, X.-L. Qi, and S.-C. Zhang, Phys. Rev. Lett. {\bf 105}, 256803 (2010)].Comment: 16 pages, 1 figure. The version accepted by PR