一种模态傅里叶-支持向量机优化的取用水监测异常数据重构方法

提高数据的完备与真实性是水资源监控能力建设的关键。针对国家水资源监控能力建设项目实施以来其监测数据呈现出的异常特征,按照“先粗筛后精选”逻辑,并考虑取用水季节性周期波动的特点,提出采用拉依达准则-模态分解-傅里叶残差修正的水监测数据异常值识别方法,并根据粒子群优化最小二乘支持向量机模型实现对异常数据的重构恢复。通过对企业取用水数据的实例分析,结果表明分段式拉依达准则在其监测异常数据的粗筛中具有较好的适用性,利用傅里叶修正集合模态分解的监测数据序列可取得更佳的拟合效果,从而达到异常数据精选的目的;而粒子群优化最小二乘支持向量机模型对异常数据重构恢复的可信度高于普通最小二乘支持向量机及传统曲线拟合数据重构方法,即该类取用水监测异常数据重构方法可有助于进一步推进其监测数据对实际水资源状态的客观反映。     

Novice facilitators’ changes in practices: From launching to managing discussions about mathematics teaching

Novice facilitators of professional development (PD) programs for mathematics teachers often face challenges in leading productive discussions and achieving the goals of these programs. Although research in this area is gradually accumulating, not much is known about how novice facilitators address these challenges and change their practices accordingly. This paper presents case studies of two novice facilitators of PD programs in two different countries. The analyses look at their work over one year, to illustrate the changes in their practices while managing discussions. The results show that although the facilitators operated in different contexts, their practices and their processes of change resembled, suggesting that these processes are not idiosyncratic. We argue that novice facilitators’ changes in practices correspond to changes in their resources, orientations, goals, and identities and that PD program teams can support these changes.     

Micro-economic analysis of the physical constrained markets: game theory application to competitive electricity markets

Competition has been introduced in the electricity markets with the goal of reducing prices and improving efficiency. The basic idea which stays behind this choice is that, in competitive markets, a greater quantity of the good is exchanged at a lower price, leading to higher market efficiency. Electricity markets are pretty different from other commodities mainly due to the physical constraints related to the network structure that may impact the market performance. The network structure of the system on which the economic transactions need to be undertaken poses strict physical and operational constraints. Strategic interactions among producers that game the market with the objective of maximizing their producer surplus must be taken into account when modeling competitive electricity markets. The physical constraints, specific of the electricity markets, provide additional opportunity of gaming to the market players. Game theory provides a tool to model such a context. This paper discussed the application of game theory to physical constrained electricity markets with the goal of providing tools for assessing the market performance and pinpointing the critical network constraints that may impact the market efficiency. The basic models of game theory specifically designed to represent the electricity markets will be presented. IEEE30 bus test system of the constrained electricity market will be discussed to show the network impacts on the market performances in presence of strategic bidding behavior of the producers.     

Parallel local search

We present a survey of parallel local search algorithms in which we review the concepts that can be used to incorporate parallelism into local search. For this purpose we distinguish between single-walk and multiple-walk parallel local search and between asynchronous and synchronous parallelism. Within the class of single-walk algorithms we differentiate between multiple-step and single-step parallelism. To describe parallel local search we introduce the concepts of hyper neighborhood structures and distributed neighborhood structures. Furthermore, we present templates that capture most of the parallel local search algorithms proposed in the literature. Finally, we discuss some complexity issues related to parallel local search.     

抽样调查的设计与分析(Ⅰ)

本文讨论抽样调查实践中有关设计和数据分析的若干问题．第一部分主要涉及设计问题．     

Public Attitudes Toward Nanotechnology

Data from 3909 respondents to an Internet survey questionnaire provide the first insights into public perceptions of nanotechnology. Quantitative analysis of statistics about agreement and disagreement with two statements, one positive and the other negative, reveals high levels of enthusiasm for the potential benefits of nanotechnology and little concern about possible dangers. The respondents mentally connect nanotechnology with the space program, nuclear power, and cloning research, but rate it more favorably. In contrast, they do not associate nanotechnology with pseudoscience, despite its imaginative exploitation by science fiction writers. Qualitative analysis of written comments from 598 respondents indicates that many ideas about the value of nanotechnology have entered popular culture, and it provides material for an additional 108 questionnaire items that can be used in future surveys on the topic. The findings of this exploratory study can serve as benchmarks against which to compare results of future research on the evolving status of nanotechnology in society.     

Statistical physics, optimization and source coding

The combinatorial problem of satisfying a given set of constraints that depend on N discrete variables is a fundamental one in optimization and coding theory. Even for instances of randomly generated problems, the question “does there exist an assignment to the variables that satisfies all constraints?” may become extraordinarily difficult to solve in some range of parameters where a glass phase sets in. We shall provide a brief review of the recent advances in the statistical mechanics approach to these satisfiability problems and show how the analytic results have helped to design a new class of message-passing algorithms — the survey propagation (SP) algorithms — that can efficiently solve some combinatorial problems considered intractable. As an application, we discuss how the packing properties of clusters of solutions in randomly generated satisfiability problems can be exploited in the design of simple lossy data compression algorithms.     

Biodegradable polymers based on renewable resources. VII. Novel random and alternating copolycarbonates from 1,4:3,6‐dianhydrohexitols and aliphatic diols

Novel copolycarbonates containing 1,4:3,6‐dianhydro‐D ‐glucitol or 1,4:3,6‐dianhydro‐D ‐mannitol units, with various methylene chain lengths, were synthesized by bulk and solution polycondensations, of several combinations of carbonate‐modified sugar derivatives and aliphatic diols. Bulk polycondensations of 1,4:3,6‐dianhydro‐2,5‐bis‐O‐(phenoxycarbonyl)‐D ‐glucitol or 1,4:3,6‐dianhydro‐2,5‐bis‐O‐(phenoxycarbonyl)‐D ‐mannitol with four α,ω‐alkanediols having methylene chain lengths of 4, 6, 8, and 10, respectively, at 180 °C afforded the corresponding copolycarbonates with number‐average molecular weight (M_n) values up to 19.₂ × 10³. ¹³C NMR analysis disclosed that these polymers had scrambled structures in which the sugar carbonate and aliphatic carbonate moieties were nearly randomly distributed along a polymer chain. However, solution polycondensations between 1,4:3,6‐dianhydro‐2,5‐bis‐O‐(p‐nitrophenoxycarbonyl)‐D ‐glucitol or 1,4:3,6‐dianhydro‐2,5‐bis‐O‐(p‐nitrophenoxycarbonyl)‐D ‐mannitol, and the α,ω‐alkanediols in sulfolane or dimethyl sulfoxide at 60 °C gave well‐defined copolycarbonates having regular structures consisting of alternating sugar carbonate and aliphatic carbonate moieties with M_n values up to 33.₈ × 10³. Differential scanning calorimetry demonstrated that all the copolycarbonates were amorphous with glass‐transition temperatures ranging from 1 to 65 °C, which decreased with increasing lengths of the methylene chain of the aliphatic diols. Additionally, all the copolycarbonates were stable up to 310–330 °C as estimated by thermogravimetric analysis. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2312–2321, 2003     

水资源可再生能力综合评价的遗传加权物元模型

为了科学地计算水资源可再生能力评价指标的权重 ,使评价方法具有可操作性 ,采用主、客观相结合的赋权基点法 ,以全局收敛的格雷码加速遗传算法为工具来确定权重 ,并结合物元分析理论 ,建立了一种新的评价模型——遗传加权物元模型 .文中给出了该模型实施的详细步骤 ,对黄河流域 9个行政分区的水资源可再生能力进行了综合评价 ,取得了较好的效果 .