创业板成长型中小企业效率评价

中小企业成长,是质与量的统一.对于创业板中小企业而言,由于多数存在经营业绩不稳定情况,因此其成长问题广受关注.首先,基于单指标识别方法,从175家企业中筛选出31家成长型中小企业,并对成长型企业的成长指数进行了计算.其次,采用数据包络分析方法,对成长型中小企业的效率进行评价,并对技术效率、纯技术效率、规模效率和成长指数进行了分析.最后,对175家企业的效率进行了综合分析,对成长型和非成长型企业效率进行了对比分析,并分别对成长速度、技术效率和企业盈利能力的关系进行了回归分析.     

基于多属性群决策模型的评教方法

对高校学生网上评教存在的主要问题进行了分析,给出了网上评教的信息处理新方法.首先利用信息熵和正态分布函数对学生可信度函数进行了定义,再根据可信度大小对学生评价的权重进行了分配,最后利用加权算术平均算子对课程班的得分进行集结.数值算例分析了方法的有效性、合理性和可操作性.     

基于数据挖掘的全球恐怖主义数据库数据分析

运用数据挖掘的方法,对全球恐怖主义数据库(以下简称GTD)进行了量化分析.建立了基于KNN邻近算法的恐怖袭击事件量化分级模型和基于K-means聚类算法的恐怖袭击事件分类模型.此外,对近三年来恐怖袭击事件发生的主要原因、时空特性、蔓延特性以及级别分布规律进行了分析.最后,基于建立的模型和分析结论,对未来全球和某些重点地区的反恐态势进行了预测分析,给出了具有针对性的建议.     

基于Elman网络预测汇率短期发展趋势

采用神经网络Elman网络模型对汇率进行预测.处理过程对样本序列进行了分类,并对训练与测试样本进行了残差分析.预测结果表明:该方法对汇率涨落方向的预测准确度达到74.54%,对汇率预测值与实际值之间的偏差略为偏大的情况,并分析了产生误差的原因.     

原子力显微镜中等容液桥的毛细力分析

用表界面热力学方法和力学方法研究了原子力显微镜中等容液桥的毛细力和液桥的断裂能,对这两种方法进行了对比分析.对液桥分析中圆弧近似的适用性进行了讨论,对轻敲模式下的能量耗散进行了分析,指出液桥断裂引起的能量耗散是引起相位变化的主要因素,另外还指出了接触角滞后效应对毛细力和断裂能的影响.模型分析对原子力显微镜轻敲模式下成像机理的理解以及力曲线测量分析有一定的参考价值.     

结合离群值对广东省进出口总额的预测分析

以国际贸易理论为基础,利用广东省若干宏观经济数据,对广东省进出口额进行实证分析.本文采用了季节性ARIMA模型并结合离群值分析的方法对进出口额进行研究.实证分析此方法具有良好的效果.     

物流企业的单品生产成本分析

生产成本是物流企业生产活动的基础.分析了物流企业生产的流程和其生产成本构成,给出了生产成本各组成部分的定量描述.并对物流成本的分摊方式进行了讨论,以给定物流企业为例,对单品成本进行了分析.对物流企业总成本和单品成本与物流量的关系进行了讨论,指出物流单品成本随相关物流量递减变化的关系.这种单品成本函数关系很好解释了物流配送的一个显著特点——规模集聚效应.     

燃料组件导向管事故工况应力计算方法研究

通过反应堆动力分析计算出堆芯上下板和围板的位移时程作为进行燃料组件地震加LOCA动力分析的输入.建立燃料组件横向排模型,进行燃料组件事故动力响应分析,得到燃料组件的变形等内容,以此作为导向管应力分析的基础.结合排模型中燃料组件的简化方法以及导向管在燃料组件中的结构分布形式,对导向管的薄膜应力以及弯曲应力的算法进行了研究,推导出导向管薄膜应力、弯曲应力的计算方法,对采用该算法进行应力分析需要注意的问题进行了阐述,给出导向管进行安全评定的方法.对导向管应力分析及评定的流程进行总结并编程实现,并以某电厂为实例进行了导向管应力分析计算.     

一维非稳态导热的火积耗散场分析

分别对无限大、半无限大物体与无限大平板非稳态导热过程的火积耗散场进行了分析,并将火积耗散场与熵产生场进行了比较.无限大物体总的火积耗散随时间的变化率为负定的,并对这一结论给出了证明.对于无限大物体,对耗散波峰的传播速度与波峰振幅进行了讨论.对于半无限大物体,分别对边界温度固定与边界热流固定两种导热情形下的火积耗散场进行了分析;对于无限大平板,分别对对流换热与绝热两种边界条件下的火积耗散场进行了分析.     

学生作弊因素的统计分析

针对目前高校校园里大学生的作弊问题,本文通过对调查问卷的统计分析对其原因进行了分析.通过对名义数据和有序数据的相关性分析,我们首先找出影响大学生作弊的因素,然后用逐步回归法和Logistic回归模型得出影响大学生作弊的主要因素.最后分析了性别和不同年级对作弊的影响,得出了许多意料之中和意料之外的答案.这些分析结果对如何进行大学生素质教育有一定的参考价值.     

岩土工程位移时间序列的组合预测研究

将组合预测方法用于岩土工程位移时间序列预测.结合实际观测数据,分别建立位移时间序列预测的GM(1,1)模型、Verhulst模型和趋势曲线模型.采用极小误差法确定各单一模型的权重,建立组合预测模型.应用表明,组合预测的精度高,为岩土工程位移预测提供了一种实用、可靠的方法.     

基于区间的土体参数敏感性分析方法研究

将一种新的工程结构不确定性分析方法——区间分析方法溶入工程参数的敏感性分析之中,获得了一种新的工程参数敏感性分析方法,进一步拓宽了区间分析方法理论的应用领域．给出了土体参数敏感性因子矩阵求解的区间分析过程,依据区间分析给出了参数区间和决策目标区间的确定方法．基于MARC软件进行了二次开发,实现了Duncan-Chang非线性弹性模型以及与Fortran程序的相互调用功能．通过工程算例验证了该方法的合理可行性,并与文献的结果进行了对比．     

A Study of STEM Assessments in Engineering,Science, and Mathematics for Elementary and Middle School Students

The purpose of this study was to develop, scale, and validate assessments in engineering, science, and mathematics with grade appropriate items that were sensitive to the curriculum developed by teachers. The use of item response theory to assess item functioning was a focus of the study. The work is part of a larger project focused on increasing student learning in science, technology, engineering, and mathematics (STEM)‐related areas in grades 4–8 through an engineering design‐based, integrated approach to STEM instruction and assessment. The fact that the assessments are available to school districts at no cost, and represent psychometrically sound instruments that are sensitive to STEM‐oriented curriculum, offers schools an important tool for gauging students' understanding of engineering, science, and mathematics concepts.     

基于AHP的深部巷道围岩稳定性影响因素评价分析

根据岩体力学和工程地质学理论,采用层次分析(AHP)法对影响深部巷道围岩稳定性的因素进行分析,从围岩岩体力学性质因素、工程地质因素、工程技术因素方面考虑,建立稳定性影响因素各项指标的递阶层次结构模型,构造判断矩阵,给出各层元素的单排序权重和总排序权重,找出影响深部巷道围岩稳定性的关键性因素,并进行定性和定量分析,为深部巷道围岩控制提供了可靠的理论依据.     

Elementary preservice teachers' integration of engineering into STEM lesson plans

Science, technology, engineering, and mathematics (STEM) integration is a desired outcome according to Next Generation Science Standards. However, learning to teach integrated STEM content has been challenging for teachers. Consequently, the purpose of this qualitative study was to describe how 16 preservice teachers enrolled in a mathematics methods course created integrated STEM lesson plans that incorporated an authentic engineering problem. Content analysis of the completed integrated STEM lesson plans used the Quality K-12 Engineering Education Framework to identify any characteristics of engineering. We found that 15 of 16 preservice teachers demonstrated at least an emerging ability to create an integrated STEM lesson that contained an engineering problem, constraints, a prototype or model, model testing, and data collection and analysis related to the model. We concluded that giving preservice teachers opportunities to experience engineering design problems could better prepare them to design and implement integrated STEM education in their classrooms. The findings from this study have practical implications for mathematics methods teacher educators who teach the pedagogy behind STEM education. This study also has theoretical implications because socially situated learning theory was extended to Model-Eliciting Activities and connected them to the K-12 Framework for Quality Engineering Education.     

基于期望函数的土遗址锚固参数组合优化方法

针对土遗址锚固工程需求，提出了一种基于期望函数的锚固参数组合优化方法.该方法通过对锚固长度、锚孔直径等参数的组合优化,获得了最大锚固力与最小遗址伤害的良好平衡.试验设计为全因子试验，利用响应面方法构建分析模型，而后将统计中的期望函数法引入锚固参数优化中，建立了多重目标响应指标与锚固参数水平的关系.研究结果表明:当分别满足锚固力最大化和遗址伤害最小化目标时，相应的锚固参数取值间存在冲突；多重响应优化能够确定目标响应需求下锚固参数的可行域范围，方便工程设计人员根据实际工程条件对锚固参数进行可视化取值.     

Experiences during development of a dynamic crash response automobile model

A finite element automobile model for use in crash safety studies was developed through reverse engineering. The model was designed for calculating the response of the automobile structure during full frontal, offset frontal, or side impacts. The reverse engineering process involves the digitization of component surfaces as the vehicle is dismantled, the meshing and reassembly of these components into a complete finite element model, and the measurement of stiffness properties for structural materials. Quasi-static component tests and full-vehicle crash tests were used to validate the model, which will become part of a finite element vehicle fleet.     

Preparing preservice elementary teachers to teach engineering: Impact on self‐efficacy and outcome expectancy

Research indicates there is a need for teachers to experience multiple mastery experiences with engineering teaching in order to improve teaching engineering self‐efficacy. To prepare future K–5 teachers to teach the engineering design process, one science methods course integrated 2‐day engineering mini‐units into the class meeting and school‐based field experience. The preservice teachers participated as students in an exemplar mini‐unit and then designed their own mini‐unit, which they later taught to K–5 students. Pre‐ and post‐testing of the preservice teachers indicated significant improvement in engineering pedagogical content knowledge self‐efficacy, engagement self‐efficacy, and disciplinary self‐efficacy. Significant improvement was not observed in engineering outcome expectancy.     

Enhancing engineering education in the elementary school

The Next Generation Science Standards emphasizes the inclusion of engineering practices throughout the K–12 science curriculum. Therefore, elementary educators need to be knowledgeable about engineering and engineering careers so that they can expose their students to engineering. The purpose of this study was to examine the effect of engineering professional development on in‐service elementary teachers’: (a) knowledge and perceptions regarding engineering, and (b) self‐efficacy of teaching engineering. This quantitative study revealed that even one professional development opportunity can help to alleviate some misconceptions about the work of engineers and what constitutes technology, as well as increase teachers’ confidence to teach engineering concepts.     

基于FETI的非协调等几何分析

基于非均匀有理B样条的等几何分析方法是一种无需网格划分的新的计算方法,旨在实现直接利用CAD模型进行分析,有望取代目前传统有限元技术．等几何分析已被成功应用在固体力学,流固耦合及拓扑优化等诸多领域．等几何分析方法要求CAD曲面或者实体高阶连续,而绝大多数CAD模型内多个曲面不但无法保持高阶连续,而且在公共界面处是几何非协调的．这一缺陷严重制约了等几何分析技术的进一步发展和应用．另外,由于采用高阶单元,等几何分析计算量较等自由度传统有限元要耗时．为解决这些难题,笔者在先前工作基础之上,提出了基于FETI方法的非协调等几何分析．新方法较以往的零空间解法更加快捷,适用于大规模数据的并行计算．数值算例表明本方法无需修改CAD模型,实施简单,精度满足要求,可处理复杂CAD模型．