ALLOCATION OF REMOTELY SENSED DATA USING MARKOV MODELS FOR IMAGE DATA AND PIXEL LABELS

For remotely sensed data, this paper reviews the Bayesian approach to the allocation of picture elements (pixels) to groups. Group labels are assumed a priori to be spatially correlated and, conditional on the labels, the image data are also assumed to be spatially correlated. The models considered have the property that the posterior distribution of the pixel labels given the image data inherits conditional independence constraints. Two allocation algorithms which exploit this fad are discussed. These algorithms are based on maximising the posterior distribution, and involve the use of neighbouring image and label data to update the label of any given pixel. The effect of spatial correlation in the image data on allocation performance is examined.     

RANDOMIZED SEARCH STRATEGIES FOR FINDING OPTIMAL OR NEAR OPTIMAL BLOCK AND ROW-COLUMN DESIGNS

We consider a family of effective and efficient strategies for generating experimental designs of several types with high efficiency. These strategies employ randomized search directions and at some stages allow the possibility of taking steps in a direction of decreasing efficiency in an effort to avoid local optima. Hence our strategies have some affinity with the simulated annealing algorithm of combinatorial optimization. The methods work well and compare favourably with other search strategies. We have implemented them for incomplete block designs, optionally resolvable, and for row-column designs.     

民族院校英语教学中实施动态教学的几种途径

民族院校少数民族学生英语水平低，很难在短时间内得到显著提高。对此，文章认为在课堂教学中，应加强动态教学。     

A hybrid heuristic for the uncapacitated single allocation hub location problem

The uncapacitated single allocation hub location problem (USAHLP), with the hub-and-spoke network structure, is a decision problem in regard to the number of hubs and location–allocation. In a pure hub-and-spoke network, all hubs, which act as switching points for internodal flows, are interconnected and none of the non-hubs (i.e., spokes) are directly connected. The key factors for designing a successful hub-and-spoke network are to determine the optimal number of hubs, to properly locate hubs, and to allocate the non-hubs to the hubs. In this paper two approaches to determine the upper bound for the number of hubs along with a hybrid heuristic based on the simulated annealing method, tabu list, and improvement procedures are proposed to resolve the USAHLP. Computational experiences indicate that by applying the derived upper bound for the number of hubs the proposed heuristic is capable of obtaining optimal solutions for all small-scaled problems very efficiently. Computational results also demonstrate that the proposed hybrid heuristic outperforms a genetic algorithm and a simulated annealing method in solving USAHLP.     

绝对离差证券组合投资模型及其模拟退火算法

马柯维兹均值—方差模型使用收益率的方差度量证券的风险, 但是实际分布呈尖顶胖尾 状, 使得方差可能不存在. 作为度量风险的标准, 绝对离差比方差更为合适. 用绝对离差刻画了 风险, 提出基于绝对离差的证券组合投资模型, 并用模拟退火算法求解. 为了比较在两种风险 标准下两种模型的优劣, 首次定义了风险弹性. 实证分析表明, 在不同收益率水平下, 风险弹性 的绝对值都大于1. 说明绝对离差模型比均值- 方差模型无论在理论上还是在实际效果上都要 更好. 实证分析还表明, 绝对离差模型中有近似的两基金分离现象存在.     

关中平原人地关系地域系统SD模型及仿真

以渭河流域关中平原为例,在深入分析系统内外因素及其反馈关系的基础上,运用系统动力学（SD）构建关中平原人地关系地域系统模型,以模型为基础,建立了关中平原发展的三种可能情景,即理想条件下、资源约束下、资源环境约束下。采用Vensim PLE软件进行系统仿真模拟,获取三种情景下系统的仿真结果。对模拟结果分析显示：水资源和环境污染对未来关中平原发展具有重大而深远的影响,盲目的追求经济发展将使资源和污染更为恶化,必须将水安全和生态环境的保护作为建设中的重点。仿真的结果对关中地区未来发展战略制定提供了理论和现实依据。     

Accuracy of Simulations for Stochastic Dynamic Models

This paper is concerned with accuracy properties of simulations of approximate solutions for stochastic dynamic models. Our analysis rests upon a continuity property of invariant distributions and a generalized law of large numbers. We then show that the statistics generated by any sufficiently good numerical approximation are arbitrarily close to the set of expected values of the model's invariant distributions. Also, under a contractivity condition on the dynamics, we establish error bounds. These results are of further interest for the comparative study of stationary solutions and the estimation of structural dynamic models.     

Partially-latinized designs

An interchange optimization algorithm to construct partially-latinized designs is described. The objective function is a weighted linear combination of up to five functions, each of which corresponds to a blocking factor of the required design. Nested simulated annealing is used to address local optima problems. The average efficiency factors of the generated designs are assessed against theoretical upper bounds.     

Resolvable Designs With Unequal Block Sizes

Resolvable block designs for v varieties in blocks of size k require v to be a multiple of k so that all blocks are of the same size. If a factorization of v is not possible then a resolvable design with blocks of unequal size is necessary. Patterson & Williams (1976) suggested the use of designs derived from α -designs and conjectured that such designs are likely to be very efficient in the class of resolvable designs with block sizes k and k – 1. This paper examines these derived designs and compares them with designs generated directly using an interchange algorithm. It concludes that the derived designs should be used when v is large, but that for small v they can be relatively inefficient.     

模拟法人之间内部结转价格的制订方法研讨

运用定量分析模型研究了国有企业再造过程中产生的企业内部模拟法人之间的内部结转价值和制订问题,提出了运用间接利用分配原则制订内部结构转价格的方法,并对这种方法的效果进行了理论分析,认为这种方法有利于缓解各利益主体之间的直接矛盾并能兼顾各方面的利益需求.