粮食产量时间序列的单分形检验及R/S预测

为探讨中国粮食产量的变化规律及趋势预测问题,采用配分函数方法,判定了1949年以来粮食总产量时间序列的单分形特征,并利用分析方法确定一个代表粮食产量变化趋势的时间序列的幂,从而得到预测粮食产量变化趋势的分形方法。根据历史资料,用此方法对中国粮食产量的变化趋势进行了短期预测,得到了变化方向上的一个估计结果。     

Significance of the Dermal Route of Exposure to Risk Assessment

The skin is a route of exposure that needs to be considered when conducting a risk assessment. It is necessary to identify the potential for dermal penetration by a chemical as well as to determine the overall importance of the dermal route of exposure as compared with inhalation or oral routes of exposure. The physical state of the chemical, vapor or liquid, the concentration, neat or dilute, and the vehicle, lipid or aqueous, is also important. Dermal risk is related to the product of the amounts of penetration and toxicity. Toxicity involves local effects on the skin itself and the potential for systemic effects. Dermal penetration is described in large part by the permeability constant. When permeability constants are not known, partition coefficients can be used to estimate a chemical's potential to permeate the skin. With these concepts in mind, a tiered approach is proposed for dermal risk assessment. A key first step is the determination of a skin-to-air or skin-to-medium partition coefficient to estimate a potential for dermal absorption. Building a physiologically-based pharmacokinetic (PBPK) model is another step in the tiered approach and is useful prior to classical in vivo toxicity tests. A PBPK model can be used to determine a permeability constant for a chemical as well as to show the distribution of the chemical systemically. A detailed understanding of species differences in the structure and function of the skin and how they relate to differences in penetration rates is necessary in order to extrapolate animal data from PBPK models to the human. A study is in progress to examine anatomical differences for four species.     

One-dimensional optimal bounded-shape partitions for Schur convex sum objective functions

Consider the problem of partitioning n nonnegative numbers into p parts, where part i can be assigned n_i numbers with n_i lying in a given range. The goal is to maximize a Schur convex function F whose ith argument is the sum of numbers assigned to part i. The shape of a partition is the vector consisting of the sizes of its parts, further, a shape (without referring to a particular partition) is a vector of nonnegative integers (n₁,..., n_p) which sum to n. A partition is called size-consecutive if there is a ranking of the parts which is consistent with their sizes, and all elements in a higher-ranked part exceed all elements in the lower-ranked part. We demonstrate that one can restrict attention to size-consecutive partitions with shapes that are nonmajorized, we study these shapes, bound their numbers and develop algorithms to enumerate them. Our study extends the analysis of a previous paper by Hwang and Rothblum which discussed the above problem assuming the existence of a majorizing shape. This research is partially supported by ROC National Science grant NSC 92-2115-M-009-014.     

论物权法和债权法的关系及对我国物权立法的启示

物权法和债权法的分立起源于罗马法.二者的分立是大陆法系民法理论分析和法典构架的基石.但近现代以来,物权法和债权法出现了融合,尤其表现为物权的债权化和债权的物权化.我国物权立法的定位和制度设计应在坚持物权法和债权法分立、物权与债权区分的前提下,针对二者融合的趋势作出立法上的调整.     

DCT域分形图像压缩编码方法

首先研究了一般分形图像压缩方法存在的缺陷，然后对它进行改进。最后在ＤＣＩ域做进一步的改进。实验结果表明，和原来方法相比较，ＤＣＴ域分形图像压缩编码方法具有明显的优越性。     

Convexity-based clustering criteria: theory,algorithms, and applications in statistics

This paper deals with the construction of optimum partitions of for a clustering criterion which is based on a convex function of the class centroids as a generalization of the classical SSQ clustering criterion for n data points. We formulate a dual optimality problem involving two sets of variables and derive a maximum-support-plane (MSP) algorithm for constructing a (sub-)optimum partition as a generalized k-means algorithm. We present various modifications of the basic criterion and describe the corresponding MSP algorithm. It is shown that the method can also be used for solving optimality problems in classical statistics (maximizing Csiszárs -divergence) and for simultaneous classification of the rows and columns of a contingency table.     

Upper Bounds for the SPOT 5 Daily Photograph Scheduling Problem

This paper introduces tight upper bounds for the daily photograph scheduling problem of earth observation satellites. These bounds, which were unavailable until now, allow us to assess the quality of the heuristic solutions obtained previously. These bounds are obtained with a partition-based approach following the divide and pas conquer principle. Dynamic programming and tabu search are conjointly used in this approach. We present also simplex-based linear programming relaxation and a relaxed knapsack approach for the problem.     

采用熵的多维K-匿名划分方法

K-匿名是数据发布应用场景下重要的隐私保护模型。近年来数据集K-匿名化的算法得到广泛的研究,Median Mondrian算法是目前唯一的多维K-匿名划分方法。文中研究了Median Mondrian算法,指出其不能有效地平衡数据划分精度与数据隐私安全性之间的矛盾,由此提出基于熵测度机制的多维K-匿名划分方法以及评估K-匿名化结果安全性的测量标准。实验表明该算法是可行的,能有效地提高数据安全性。     

市场的制度性分割:经济适用房制度的博弈分析

为低收入者提供基本住房保障是政府的基本职责,经济适用房是实现该职责的一个制度体现.但是中国的经济适用房制度并没有实现其设计目标.那么是什么原因导致了这个结果,如何实现为低收入者提供基本住房保障的目标?从政府、开发商、购买者三方博弈的角度,可以发现经济适用房制度失败的关键在于它造成了市场的制度性分割,由此产生的市场套利行为瓦解了经济适用房的制度基础.改革方向在于撤销经济适用房制度,实施住房补贴制度,重新建立统一的住房市场.     

Inégalités et mondialisation financière: le rapport qui tombe à pic

Cette note présente la nouvelle publication annuelle de l'Institut international d'études sociales de l'OIT, le Rapport mondial sur le travail 2008, dont le thème est les inégalités de revenu à l'épreuve de la mondialisation financière. Cette publication tombe à point nommé au moment où l'on s'inquiète de l'ampleur, de la durée et des conséquences économiques et sociales de la crise financière. Le rapport traite des déterminants de l'accroissement des inégalités de revenu, et de ses liens avec la mon‐dialisation financière, les institutions du marché du travail, les emplois – création et caractéristiques –, et les politiques de redistribution.