基于面板模型的商品房价格影响因素的实证研究

选取了我国30个省市2006~2015年的面板数据,应用面板数据计量模型回归的方法,基于R语言对影响商品房价格的因素进行实证研究.首先,经过Hausman检验与F检验确定面板数据的模型为混合估计模型;模型可以通过十折交叉验证法、残差正太性的检验、Q-Q图检验、变量间共线性的检验;最后经过逐步回归分析,结果表明土地价格、商品房销售面积、居民可支配收入、人均国内总产值财政收入占地区生产总值比重、汇率这6个指标对商品房价格都有显著性的影响.其中,土地价格和居民可支配收入对商品房价格的影响最为突出.     

Neumann problems with resonance in the first eigenvalue

The aim of this work is to present results of existence of solutions for a class of superlinear asymmetric elliptic systems with resonance in the first eigenvalue. The asymmetry that we consider has linear behavior on and superlinear on . To obtain these results we apply topological degree theory.     

Strict topologies on measure spaces

Let X be a measurable space, let be a family of measurable subsets of it, and let be a subspace of complex measures on X that is also closed under restrictions of measures. In this paper we introduce the ‐convergence topology and the ‐strict topology on . Among other results, we find necessary and sufficient conditions for Hausdorff‐ness and coincide‐ness of these topologies. Applications to Lebesgue spaces, and also examples in Hausdorff topological spaces and locally compact groups are given.     

Programming With Models: Writing Statistical Algorithms for General Model Structures With NIMBLE

We describe NIMBLE, a system for programming statistical algorithms for general model structures within R. NIMBLE is designed to meet three challenges: flexible model specification, a language for programming algorithms that can use different models, and a balance between high-level programmability and execution efficiency. For model specification, NIMBLE extends the BUGS language and creates model objects, which can manipulate variables, calculate log probability values, generate simulations, and query the relationships among variables. For algorithm programming, NIMBLE provides functions that operate with model objects using two stages of evaluation. The first stage allows specialization of a function to a particular model and/or nodes, such as creating a Metropolis-Hastings sampler for a particular block of nodes. The second stage allows repeated execution of computations using the results of the first stage. To achieve efficient second-stage computation, NIMBLE compiles models and functions via C++, using the Eigen library for linear algebra, and provides the user with an interface to compiled objects. The NIMBLE language represents a compilable domain-specific language (DSL) embedded within R. This article provides an overview of the design and rationale for NIMBLE along with illustrative examples including importance sampling, Markov chain Monte Carlo (MCMC) and Monte Carlo expectation maximization (MCEM). Supplementary materials for this article are available online.     

Diophantine equations and the generalized Riemann hypothesis

We show that, for a listable set P of polynomials with integer coefficients, the statement “for all roots θ of all polynomials in P, the generalized Riemann hypothesis for Q(θ) holds” is Diophantine. That is, the statement is equivalent to the unsolvability of a particular Diophantine equation. This is achieved by finding a decidable property P such that the aforementioned statement may be written in the form “P holds for all natural numbers”.     

Homogenization of a parabolic model of ferromagnetism

This work deals with the homogenization of hysteresis-free processes in ferromagnetic composites. A degenerate, quasilinear, parabolic equation is derived by coupling the Maxwell-Ohm system without displacement current with a nonlinear constitutive law:

     

The higher derived functors of the primitive element functor of quasitoric manifolds

Let P be an n-dimensional, q?1 neighborly simple convex polytope and let M2n(λ) be the corresponding quasitoric manifold. The manifold depends on a particular map of lattices λ:Zm→Zn where m is the number of facets of P. In this note we use ESP-sequences in the sense of Larry Smith to show that the higher derived functors of the primitive element functor are independent of λ. Coupling this with results that appear in Bousfield (1970) [3] we are able to enrich the library of nice homology coalgebras by showing that certain families of quasitoric manifolds are nice, at least rationally, from Bousfield?s perspective.     

A dichotomy for the convex spaces of probability measures

We show that every nonempty compact and convex space M of probability Radon measures either contains a measure which has ‘small’ local character in M or else M contains a measure of ‘large’ Maharam type. Such a dichotomy is related to several results on Radon measures on compact spaces and to some properties of Banach spaces of continuous functions.