关键词： 学习有效性   终身学习能力   教育热点   学习活动   算法分析   算法问题   学习效率   思辨能力   思维能力   方法目标  

摘要： 随着新一轮基础教育课程改革的展开,＂校本课程＂这个外来语逐渐渗透到我们的教育活动中。开发怎样的校本课程、怎样开发校本课程,逐渐成为教育热点。笔者认为,从学生的需要出发,培养学习兴趣,提高学习有效性和终身学习能力的校本课程才是学校、教师、学生真正需要的课程。

关键词： 高考数学   数学算法   分段函数   分析算法   填空题   算法程序   循环结构   数学内容   计算能力   程序框图  

摘要： 算法初步是高中数学内容的基本组成部分,基本的算法语句包括输入语句、输出语句、赋值语句及其循环语句、条件语句.在高考中常以函数、统计及数列的知识为背景,涉及赋值、累乘、交换及分段函数等问题,以选择题或填空题的形式出现,注重考查学生的基本技能、理解能力及数学思想.为此,研究高考算法初步的命题现状及解题可为学生备考提供参考依据,提高解题效率.

关键词： 超声心动描记术   微气泡   心肌梗死   心室功能,左   图像处理,计算机辅助  

摘要： 目的 探讨基于改进数学形态学算法的自制心肌超声造影（MCE）软件定量评价心肌梗死大鼠模型左室收缩功能的准确性及其应用价值.方法 SD大鼠制成心肌梗死模型,分别于术前、术后1周及3周对其进行MCE检查.体外实验：基于二值形态学的原理,采用膨胀、腐蚀、闭合运算以及对对象标记的连通域搜索的方法自动分割心内膜,并与人工分割结果比较.体内实验：应用该软件对心肌梗死大鼠左室面积自动计算,并获得左室收缩功能新指标—左室面积变化率（AVF）.AVF与左室射血分数（LVEF）行相关分析.ROC曲线评价AVF对左心功能不全者的诊断效能.结果 ①自动分割获得心内膜轮廓与人工分割的轮廓具有良好的吻合度,交互相关系数（CCC）在0.90以上,误差百分比（PE）在9％以下;②AVF与LVEF呈正相关（r=0.934,P＜0.001）;③ROC曲线分析：AVF诊断左室收缩功能不全（LVEF＜50％）的曲线下面积为0.834,以AVF=27.5％为截断值诊断左室收缩功能不全的敏感性85％,特异性60％.结论 基于改进数学形态学算法的MCE可以实现对左室心内膜的自动、快速、准确的识别,而由此衍生的AVF能对实验大鼠左室收缩功能进行定量评估.

关键词： speech codec   VoIP   algebraic codebook search   reduced candidate mechanism (RCM)  

摘要： In a bid to enhance the search performance, this paper presents an improved version of reduced candidate mechanism (RCM), an algebraic codebook search conducted on an algebraic code-excited linear-prediction (ACELP) speech coder. This improvement is made on the basis of two findings in our prior work. The first finding is that a pulse with a high contribution in the associated track is more likely to serve as the optimal pulse in the optimal codevector;the second is that the speech quality can be well maintained at a search accuracy above 50% approximately. Subsequently, a new finding in this study is that there is a 0.8321 probability that the No. 1 ranked pulse in a global sorting by pulse contribution is indeed one of the optimal pulses. Hence, the No. 1 pulse in the global sorting is labeled as one of the optimal pulses, following which a sequence of search tasks is fulfilled through RCM. This proposed complexity reduction algorithm, implemented on a G.729A speech codec, takes as few as eight searches, a search load amounting to 2.5% of G.729A, 12.5% of global pulse replacement method (iteration = 2), 16.7% of iteration-free pulse replacement method, and 50% of RCM (N = 2). This proposal is thus found to successfully reduce the required computational complexity to a great extent as intended. (c) 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

关键词： scheduling   flow shop   assembly   hybrid MOPSO-GA algorithm   makespan   sum of earliness and tardiness costs  

摘要： This study is devoted to schedule a three-stage manufacturing system including machining, assembly and batch processing stages. The system is supposed to be capable of manufacturing a variation of products. At the first stage, the need for machining raw parts causes the manufacturer to deal with a flow shop scheduling problem. In the next stage, processed parts should be assembled together in order to form desired products. It is noteworthy that several operations are not allowed to be executed simultaneously on the same machine. Second stage should be considered as a single-assembly line or a single team of operators, and finally the manufacturing processing stage. The considered objectives are to minimize completion time of all products (makespan) and sum of the earliness and tardiness costs, simultaneously. First, the proposed scheduling problem is formulated into a mixed-integer mathematical model, and then owing to the NP-hardness of the concluded model a meta-heuristic approach is applied. A hybrid algorithm is modified to create a powerful method in searching the discrete solution space of this problem by taking advantage of superiorities of both Genetic Algorithm and Particle Swarm Optimization methods. Numerical experiments are designed to evaluate the performance of the proposed algorithm.

关键词： X-ray specular reflectivity   Canonical atomic distribution function   Regularization   Low contrast multilayer nanoheterostructure   Depth-profile of element  

摘要： It is shown that X-ray specular reflectivity may be described in terms of canonical distribution functions (CDFs) p(j)(z) which is a probability to find an element of sort j at a depth z from the sample surface. The problem reduces to determine K CDFs, where K is the number of elements in the multilayer sample. Using the properties of the canonical functions, we have introduced the interface function pint(z) and use it as one unknown function at solving the integral equation. The integral Fredholm equation of the first kind belongs to the class of ill-posed problems and for solving it needs special methods. We use the Tikhonov regularization method. This method is applied to study the low contrast multilayer systems. (C) 2014 Elsevier Ltd. All rights reserved.

关键词： 算理   算法   数形结合   操作体验  

摘要： 计算教学改革经历了两个明显的阶段:第一阶段,教材选定算法——教师讲解算法——学生模仿算法——练习强化算法;第二阶段,倡导"算法多样化"的教学理念。综观两个阶段,都极大程度上强调了算法,而忽略了算理。笔者结合自己所执教的《9的乘法口诀》,谈谈关于计算教学中的点滴体会。

关键词： 矩阵变换器   输入滤波器   数学构造   单位功率因数   补偿能力  

摘要： 为了滤除矩阵变换器的输入电流高频谐波成分,需要安装输入滤波器。然而,输入滤波器会影响矩阵变换器输入功率因数,尤其在轻载运行情况下影响较大。为了在更宽范围内实现单位功率因数运行,提出一种基于数学构造的输入功率因数补偿算法,算法采用预估-校正思想,实现了更宽范围的精确单位功率因数运行,同时也不依赖输入滤波器的具体参数。实验结果验证了所提算法的正确性与可行性。

关键词： Mathematical model   Assembly scheduling   Two-stage production system  

摘要： In a recent paper by Fattahi et al. (Int J Adv Manuf Technol 65:787-802, 2013), a mathematical model is presented for a two-stage assembly scheduling problem containing a hybrid flow shop and an assembly stage. Some constraints in the model are not valid. This note shows that some new constraints are proposed for the mathematical model. An example is proposed to present and prove this new model by executing mathematical software.