住房价格波动对自有住房家庭消费的区域异质性影响研究

为了解决八大类消费品价格数据不易得到的难题,本文构建投入产出价格模型,分别经验研究25个省(自治区和直辖市)住房价格同时变动不同幅度对八大类消费品价格的影响。25个省(自治区和直辖市)消费品价格变动幅度结果即为QUAIDS模型中的消费品价格变量。然后,本文采用CFPS2010数据,在QUAIDS模型中加入反映家庭所在地区的人口特征变量,研究住房价格波动对自有住房家庭消费的区域异质性影响。研究结果表明住房价格波动对自有住房家庭生存型消费需求区域异质性影响的财富效应显著,而对享受型和发展型消费需求区域异质性影响的挤出效应显著。在此基础上,本文进一步运用补偿变动研究住房价格波动对自有住房家庭福利的区域异质性影响。研究结果表明为了提高自有住房家庭的生活质量和促进社会的和谐稳定,政府应该把稳定东部地区住房价格放在首位。且当遇到如何优化家庭消费结构问题时,政府应该根据地区差异划分市场。     

Partial hybrid finite elements for composite laminates

Three types of partial hybrid finite elements are presented in order to set up a global/local finite element model for analysis of composite laminates. In the global/local model, a composite laminate is divided into three different regions: global, local, and transition regions. These are modeled using three different elements. In the global region, a 4-node degenerated plate/shell element is used to model the overall response of the composite laminate. In the local region, a multilayer element is used to predict detailed stress distribution. In the transition region, a multilayer transition element is used to smoothly connect the two previous elements. The global/local finite element model satisfies the compatibility of displacement at the boundary between the global region and the local region. It also satisfies the continuity of transverse stresses at interlaminar surfaces and traction conditions on the top and bottom surfaces of composite laminates. The global/local finite element model has high accuracy and efficiency for stress analysis of composite laminates. A numerical example of analysis of a laminated strip with free edge is presented to illustrate the accuracy and efficiency of the model.     

Packet reordering in networks with heavy-tailed delays

An important characteristic of any TCP connection is the sequencing of packets within that connection. Out-of sequence packets indicate that the connection suffers from loss, duplication or reordering. More generally, in many distributed applications information integrity requires that data exchanges between different nodes of a system be performed in a specific order. However, due to random delays over different paths in a system, the packets may arrive at the receiver in a different order than their chronological order. In such a case, a resequencing buffer at the receiver has to store disordered packets temporarily. We analyze both the waiting time of a packet in the resequencing buffer and the size of this resequencing queue. We derive the exact asymptotics for the large deviation of these quantities under heavy-tailed assumptions. In contrast with results obtained for light-tailed distributions, we show that there exists several “typical paths” that lead to the large deviation. We derive explicitly these different “typical paths” and give heuristic rules for an optimal balancing.     

中国报纸出版业区域发展不均衡性的计量分析

依我国各省(市、自治区)报纸种数、报纸总印数和报纸总印张数等三个指标1986-2006年的数据,构建这一时期各指标相对熵的时间序列。应用ADF检验求时间序列单整阶数并做出分析,应用方向数据统计探讨报纸总印张数相对熵的周期变化。     

Groups of even type which are not of even characteristic,I

In the ongoing revision of the classification of the finite simple groups there is a subdivision into two classes of groups, which reflects whether semisimple elements or unipotent elements are the primary focus of the investigation. While semisimple methods naturally lead to the definition of groups of even type, unipotent methods, notably the amalgam method, naturally lead to groups of even characteristic. This paper clarifies the relationship between the two definitions and thus makes the amalgam method available for use in the classification of groups of even type.     

多指标决策与评价的新方法——主成份投影法

本文介绍了主成份投影法的原理和实施步骤 ,并对全国 31个省、自治区和直辖市的 1998年经济效益指标进行综合分析和排序     

Involutions of Type G<Subscript>2</Subscript> Over Fields of Characteristic Two

We continue a study of automorphisms of order 2 of algebraic groups. In particular we look at groups of type G₂ over fields k of characteristic two. Let C be an octonion algebra over k; then Aut(C) is a group of type G₂ over k. We characterize automorphisms of order 2 and their corresponding fixed point groups for Aut(C) by establishing a connection between the structure of certain four dimensional subalgebras of C and the elements in Aut(C) that induce inner automorphisms of order 2. These automorphisms relate to certain quadratic forms which, in turn, determine the Galois cohomology of the fixed point groups of the involutions. The characteristic two case is unique because of the existence of four dimensional totally singular subalgebras. Over finite fields we show how our results coincide with known results, and we establish a classification of automorphisms of order 2 over infinite fields of characteristic two.     

Delimitation of service areas in reverse logistics networks with multiple depots

This paper describes a heuristic approach for the definition of service (or influence) areas of multiple depots in a reverse logistics network. This work is based on a case study: the recyclable waste collection system with 5 depots that covers seven municipalities in the Alentejo region, southern Portugal. The system optimization considers two objectives, related with economic and organizational issues: minimizing the variable costs (function of the travelled distances by the collection vehicles), and the pursuit of equity, aiming at minimizing the workload differences among depots. The goal of balancing workloads poses a problem not usually treated in the existing literature. This fact required the development of a new approach with innovative elements adjusted to the existing circumstances.     

Radical algebras subgroups of whose adjoint groups are subalgebras

We obtain the characteristic for radical algebras subgroups of whose adjoint groups are subalgebras. In particular, we prove that the algebras of this sort are nilpotent with nilpotent length at most three. We give the complete classification of those algebras under consideration which are generated by two elements. Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 49, No. 12, pp. 1646–1652, December, 1997.     

A model and approach to the challenge posed by optimal power systems planning

Currently, there is a need to plan and analyze the electric power transmission system in greater detail and over larger geographic areas. Existing models approach the problem from different perspectives. Each model addresses different aspects of and has different approximations to the optimal planning process. In order to scope out the huge challenge of optimal transmission planning, this paper presents a new modeling approach for inter-regional planning and investment in a competitive environment. This modeling approach incorporates the detailed generator, topology and operational aspects found in production cost planning models into a larger framework that can find optimal sets of transmission expansion projects. The framework proposed here can be used in an auction to award investment contracts or as a part of a more general policy analysis. The solution yields the set of transmission projects that have the highest expected benefits, while also representing generic generation expansions under the same objective. The model is a two-stage, mixed-integer, multi-period, N-1-reliable model with investment, unit commitment, and transmission switching. The combination of combinatorial, stochastic and operational elements means this model may be computationally intractable without judicious modelling aggregations or approximations to reduce its size and complexity. Nevertheless we show via a dual problem that analysing the economics and sensitivity of the solution is computationally more straightforward.     

Finite field elements of high order arising from modular curves

In this paper, we recursively construct explicit elements of provably high order in finite fields. We do this using the recursive formulas developed by Elkies to describe explicit modular towers. In particular, we give two explicit constructions based on two examples of his formulas and demonstrate that the resulting elements have high order. Between the two constructions, we are able to generate high order elements in every characteristic. Despite the use of the modular recursions of Elkies, our methods are quite elementary and require no knowledge of modular curves. We compare our results to a recent result of Voloch. In order to do this, we state and prove a slightly more refined version of a special case of his result.      

Realizability and automatic realizability of Galois groups of order 32

This article provides necessary and sufficient conditions for each group of order 32 to be realizable as a Galois group over an arbitrary field. These conditions, given in terms of the number of square classes of the field and the triviality of specific elements in related Brauer groups, are used to derive a variety of automatic realizability results.     

Smooth Compactly Supported Solutions of Some Underdetermined Elliptic PDE,with Gluing Applications

We give sufficient conditions for some underdetermined elliptic PDE of any order to construct smooth compactly supported solutions. In particular we show that two smooth elements in the kernel of certain underdetermined linear elliptic operators P can be glued in a chosen region in order to obtain a new smooth solution. This new solution is exactly equal to the initial elements outside the gluing region. This result completely contrasts with the usual unique continuation for determined or overdetermined elliptic operators. As a corollary we obtain compactly supported solutions in the kernel of P and also solutions vanishing in a chosen relatively compact open region. We apply the result for natural geometric and physics contexts such as divergence free fields or TT-tensors.     

Word length in surface groups with characteristic generating sets

A subset of a group is characteristic if it is invariant under every automorphism of the group. We study word length in fundamental groups of closed hyperbolic surfaces with respect to characteristic generating sets consisting of a finite union of orbits of the automorphism group, and show that the translation length of any element with a nonzero crossing number is positive, and bounded below by a constant depending only (and explicitly) on a bound on the crossing numbers of generating elements. This answers a question of Benson Farb.

     

Dynamic evolution of economically preferred facilities

In a sustained development scenario, it is often the case that an investment is to be made over time in facilities that generate benefits. The benefits result from joint synergies between the facilities expressed as positive utilities specific to some subsets of facilities. As incremental budgets to finance fixed facility costs become available over time, additional facilities can be opened. The question is which facilities should be opened in order to guarantee that the overall benefit return over time is on the highest possible trajectory. This problem is common in situations such as ramping up a communication or transportation network where the facilities are hubs or service stations, or when introducing new technologies such as alternative fuels for cars and the facilities are fueling stations, or when expanding the production capacity with new machines, or when facilities are functions in a developing organization that is forced to make choices of where to invest limited funding.     

A Deformation Model for Monotropic Plastic Foams under Compression/Tension Perpendicularly to the Foam Rise Direction

The deformation properties of monotropic plastic foams under uniaxial compression or tension perpendicularly to the foam rise direction are considered. Theoretical results are obtained for the case where the volume- deformation hypothesis is assumed. In order to perform numerical calculations, the foams are devided into three groups with different degrees of monotropy. For these groups, different methods of calculating the numerical value of the relative volume strain are used. The Young's modulus in the plane of isotropy is determined using both the mixed Reuss-Voigt and Voigt averaging. The Poisson ratios are expressed using the Reuss averaging. If only the axial deformation of the load-bearing elements (polymer struts) is allowed for, the results obtained do not agree with experimental data. Therefore, we also take into account the changes in their orientation. The values of Young's modulus and Poisson ratios are obtained for a wide range of degrees of extension of the model cell. A comparison of the theoretical results with the experimental data available shows a satisfactory agreement.     

On the category of weak Cayley table morphisms between groups

Weak Cayley table functions between groups are generalized conjugacy-preserving homomorphisms, under which products of images are conjugate to images of products. There is a weak Cayley table bijection between two groups iff they have the same 2-characters. In this paper, weak Cayley table functions are augmented to include the specific conjugating elements, leading to the concept of a weak (Cayley table) morphism. If the conjugating elements are chosen subject to a crossed-product condition, then the weak morphisms between groups form a category. The forgetful functor to this category from the category of group homomorphisms is shown to possess a left adjoint. Two weak morphisms are said to be homotopic if they project to the same weak Cayley table function. As a first step in the analysis of the category of weak morphisms, the group of units of the monoid of weak morphisms homotopic to the identity automorphism of a group is described.     

The bounded Lie Engel property on torsion group algebras

Let F be a field of characteristic different from 2 and G a group with involution ∗. Extend the involution to the group ring FG, and write (FG)⁻ for the Lie subalgebra of FG consisting of the skew elements. We classify the torsion groups G having no elements of order 2 such that (FG)⁻ is bounded Lie Engel.     

A fuzzy system for municipalities classification

A knowledge-based fuzzy system for the purpose of municipalities classification is presented in this paper. It illustrates how fuzzy systems can be used for municipalities classification and ranking tasks. The application of the system is explained by the example of classification in one region in the Slovak Republic. The original problem of estimating and rough planning of road maintenance requirements in winter was examined. The suggested methodology is supported by GIS technology for visualization of the ranked municipalities to offer a better view on the territorial distribution of the obtained solution. A disadvantage of fuzzy systems for the end user is in their complexity. This disadvantage has been analysed and a solution is suggested to overcome it. The proposal deals with the integration of information system and self developed fuzzy system. This integration enables creating the model, importing input data, processing rules and presenting results in tables and maps in one integrated tool.