指向学科核心素养的高中生物学情境套题命制及改进

本文以区级原创情境套题“高原鼠兔”为例,阐述了指向学科核心素养的试题情境选择、有价值的试题素材的搜集和选择、情境套题的情境材料和问题串编写、初稿情境材料中的数据和图的修改、试题中逻辑问题的发现和修改等试题命制的路径和改进方法,使试题表现较好的核心素养水平的进阶梯度,提高指向学科核心素养的命题质量。

体育统计套题命题考试信度、效度检验及质量分析

通过对体育统计学套题命题考试信度、效度、正态性检验等综合量化分析,为现有套题的不断改进和完善,进一步提高命题科学性,建立合理的控制模式,以及将来实现计算机题库命题考试提供了必要的参考依据。

谈谈高三数学的套题训练

高三数学套题训练是复习过程中的重要环节,怎样才能提高复习效率.笔者认为要做到：在训练前要有目标,训练中有竞争,训练后出成果.

Genetic Algorithms to the Nesting Problem in the Leather Manufacturing Industry

The nesting problem in the leather manufacturing is the problem of placing a set of irregularly shaped pieces (called stencils) on a set of irregularly shaped surfaces (called leathers sheets). This paper presents a novel and promising processing approach. After the profile of leather sheets and stencils is obtained with digitizer, the discretization makes the processing independent of the specific geometrical information. The constraints of profile are regarded thoroughly. A heuristic bottom-left placement strategy is employed to sequentially locate stencils on sheets. The optimal placement sequence and rotation are deterimined by genetic algorithms (GA). A natural concise encoding method is developed to satisfy all the possible requirements of the leather nesting problem. The experimental results show that the proposed algorithm can not only be applied to the normal two-dimensional nesting problem, but also especially suitable for the placement of multiple two-dimensional irregular stencils on multiple two-dimensional irregular sheets.

Fresh views on some recent developments in the simplex algorithm

First, the main procedures and the distinctive features of the most-obtuse-angle（MOA）row or column pivot rules are introduced for achieving primal or dual feasibility in linear programming. Then, two special auxiliary problems are constructed to prove that each of the rules can be actually considered as a simplex approach for solving the corresponding auxiliary problem. In addition, the nested pricing rule is also reviewed and its geometric interpretation is offered based on the heuristic characterization of an optimal solution.

Coupling problem between the dynamical and tribological behaviors in the piston-liner systems of multi-cylinder IC engines

This paper deals with the coupling problem between the dynamic behaviors and the tribological behaviors of the piston-liner systems in multi-cylinder internal combustion engines. Firstly, based on the correction of some errors in the equation of piston secondary motion, which have been employed by many authors for several years, a detailed mathematical model for the coupling problem between the dynamical and tribological behaviors in the piston-liner systems of multi-cylinder internal combustion engines is presented. Secondly, the lubrication and friction between the liner and piston in each cylinder is included applying the average flow model of the Reynolds equation. Thirdly, the vibration of each liner is computed through the finite element model of a four-cylinder engine block, by which not only the liner motions caused by the block vibration but also the local vibration and the local static deformation of each liner can be figured out and taken into account. Through theoretical analysis and computation, some conclusions can be drawn as: 1) Both the liner vibration and piston motion are different for different cylinder in a multi-cylinder internal combustion engine, and hence different piston-liner systems will have different tribological behaviors. 2) Different liners have coincident dynamic response on the whole, especially for the lower frequency components. However, differences still exist among the vibrations of different liners, and these differences are mainly owing to the higher frequency components. 3) The impacts of liner vibrations on the tribological behaviors in piston-liner systems are primarily ascribed to its higher frequency components.

高考作文“文体”商榷

近年来,不论是《高中语文课程标准》还是高考语文《考试说明》,对“写作”这一模块表述均是:“能写论述类、实用类和文学类文章。”由此,我们有必要重新来审视一下“文体”以及由问题引发的“仅限”与“不限”的问题。可以说,“文体”的发展历程有点曲折,曾经有过很长一段时间处于“一统天下”的局面,后来慢慢招致多方诟病,于是很多省份的高考命题中出现了“文体不限”的说明,但发展至今,仍然存在不少问题,比如限制过宽,容易套题,文章四不像,评价分寸不好把握等等。于是,经常出现“文体鲜明,但言之无物”和“文体特征不鲜明”两个极端的作文。

Post-J test inference in non-nested linear regression models

This paper considers the post-J test inference in non-nested linear regression models. Post-J test inference means that the inference problem is considered by taking the first stage J test into account. We first propose a post-J test estimator and derive its asymptotic distribution. We then consider the test problem of the unknown parameters, and a Wald statistic based on the post-J test estimator is proposed. A simulation study shows that the proposed Wald statistic works perfectly as well as the two-stage test from the view of the empirical size and power in large-sample cases, and when the sample size is small, it is even better. As a result,the new Wald statistic can be used directly to test the hypotheses on the unknown parameters in non-nested linear regression models.

A NOTE ON THE NESTEDNESS PROPERTY FOR ORDERED MEDIAN PROBLEMS IN TREE NETWORKS

The nestedness property has become an increasingly important means for devising efficient algorithms for network location problems.There have been attempts to explore the nestedness property of network location problems with some special cases of the convex ordered median objectives.However,there is little research on the nestedness property for those problems with the concave ordered median objectives.This paper constructs a tree network T and shows that the nestedness property cannot hold for the concave ordered median problem,which fills a gap in the research on the nestedness property.Finally,the authors pose an open problem on identifying the nestedness property for the continuous strategic ordered median problem.

Hierarchical topic modeling with nested hierarchical Dirichlet process

This paper deals with the statistical modeling of latent topic hierarchies in text corpora. The height of the topic tree is assumed as fixed, while the number of topics on each level as unknown a priori and to be inferred from data. Taking a nonpara-metric Bayesian approach to this problem, we propose a new probabilistic generative model based on the nested hierarchical Dirichlet process (nHDP) and present a Markov chain Monte Carlo sampling algorithm for the inference of the topic tree structure as well as the word distribution of each topic and topic distribution of each document. Our theoretical analysis and experiment results show that this model can produce a more compact hierarchical topic structure and captures more fine-grained topic rela-tionships compared to the hierarchical latent Dirichlet allocation model.