关键词： 小学数学   算法多样化   价值取向   优化  

摘要： 近年来,随着教育事业的快速发展,数学教学在教法和学法上出现了新的变化。特别是小学数学教学中的算法更受人观注,算法多样化对学生的影响更为深远。但是,在实施的过程中出现了一些误区。需要我们重新去认识其中的一些关系,做出正确处理的办法。

关键词： selective disassembly sequencing   multiple target components   sequence-dependent setups   integer programming   heuristics  

摘要： This study considers selective disassembly sequencing under the sequential disassembly environment in which one component is obtained at each disassembly operation. The problem is to determine the sequence of disassembly operations to obtain multiple target components of a used or end-of-life product for the purpose of repair, reuse, remanufacturing, disposal, etc. In particular, we consider sequence-dependent setups in which setup costs depend on the disassembly operation just completed and on the operation to be processed. The problem is represented as a disassembly precedence graph and then a new integer programming model is suggested for the objective of minimising the total disassembly cost. After it is proved that the problem is NP-hard, we suggest two types of heuristics: (1) branch and fathoming algorithm for small-to-medium-sized instances;and (2) priority-rule-based algorithm for large-sized instances. A series of computational experiments, i.e., effectiveness of the new integer programming model and performances of the two heuristic types, were done on various test instances, and the results are reported. In addition, to show the applicability of the mathematical model and the solution algorithms, a case study is reported on an end-of-life electronic calculator.

关键词： Pattern classification   Writer identification   Plane curvature   Curve fitting   Dating ancient inscriptions   Dating Byzantine codices   Contours similarity  

摘要： In this paper, a novel approach is introduced for classifying curves into proper families, according to their similarity. First, a mathematical quantity we call plane curvature is introduced and a number of propositions are stated and proved. Proper similarity measures of two curves are introduced and a subsequent statistical analysis is applied. First, the efficiency of the curve fitting process has been tested on 2 shapes datasets of reference. Next, the methodology has been applied to the very important problem of classifying 23 Byzantine codices and 46 Ancient inscriptions to their writers, thus achieving correct dating of their content. The inscriptions have been attributed to ten individual hands and the Byzantine codices to four writers. (C) 2013 Elsevier Ltd. All rights reserved.

关键词： Data broadcast   Data retrieval   Algebraic algorithm   Mobile computing  

摘要： Wireless data broadcast is an important data dissemination method for distributing public information to mobile users. Due to the exponentially increasing number of mobile network users, it is necessary to develop efficient data retrieval protocols for end users to download data items effectively. In this paper, we concentrate on investigating scheduling algorithms for retrieving a set of data items from a multichannel wireless data broadcast system. As we know, the most important issues in mobile computing are energy efficiency and query response efficiency. However, in data broadcast the objectives of reducing access latency and energy cost can be contradictive to each other. Consequently, we define a new problem named Minimum Constraint Data Retrieval Problem (MCDR). We prove that MCDR is NP-hard, and then show a fixed parameter tractable algorithm which can balance two factors together. It has computational time O(2(k)(hnt)O-(1)), where n is the number of channels, k is the number of required data items, t is the maximal time slot, and h is the maximal number of channel switches. (C) 2012 Elsevier B.V. All rights reserved.

关键词： 算法多样化   告诉   体验   择优   解决问题   课程目标  

摘要： 算法多样化贯穿于我们的整个教学系统,让传统的"告诉"教学模式转变为"体验"学习方式;教学不能仅仅是倡导多样化,还要顺学而导实现"择优";算法学习还要和解决问题的能力培养有机整合;要重视学生思维多样化的培养;需要教师合理地开发课程资源,传承传统教学中的优势优化教学;实现"不同的人在数学上得到不同的发展"的课程目标。

关键词： 盲信号处理   踝臂指数   主成分分析   数学形态学  

摘要： 踝臂指数(ABI)的准确测量在临床医学诊断中具有重要意义。在测量踝臂指数时,准确测量上下肢收缩压是测量的关键。当袖带加压到可以阻断血管中血液流动时开始缓慢放气,脉搏重新恢复波动的第一个脉搏波所对应的袖带压力就等于收缩压。由于在袖带加压时,不能完全阻断下肢所有血管的血液流动,这样很难准确测量下肢动脉的收缩压。利用PCA算法将混合的脉搏波信号进行分离,对分离后的脉搏波数据用数学形态学的形态梯度理论进行处理。实验表明:将采集的脉搏波信号分离后,应用基于数学形态学的形态学梯度理论可以成功找到脉搏波重新恢复波动的起点,从而可以准确地测量ABI。

关键词： 算法多样化   小学数学   学生主动参与   实践   学习方式   尊重学生   学习主体   思考角度  

摘要： 新课程倡导学生主动参与，乐于探究，勤于动手的学习方式，尤其突出学习主体的独立性——用我的方法学。由于学生生活背景和思考角度不同，已有的知识经验和思维方式也不同，因而计算所使用的方法必然是多样的。教师应尊重学生的想法，鼓励学生独立思考，提倡计算方法的多样化。但教学中我们也应认识到“算法多样化”不是量的变化，而是学习方式的变化，教学中不能一味追求方法多，而忽略学生的接受能力。更不能硬逼着孩子去想多种方法，扼杀学生思维的创造性，一切应从学生实际出发，尊重学生的个性，引导学生的自主探索，从而实现个性化的学习。

关键词： 数学形态学   多结构元素   边缘提取  

摘要： 提出了一种基于形态学的OCT图像的边缘检测方法,即对原始图像预处理,增加图像的对比度和边缘特性,使用形态学腐蚀和膨胀两个基本算子进行,选取了合适的结构元素,最后采用canny算法提取边缘。实验结果表明,经过改进的数学形态学方法处理的图像边缘特性的提取效果显著增强,且效率高、处理速度快。与经典的边缘检测算子和传统形态学边缘检测算法相比,该算法优势更加明显,边缘提取质量显著提高,且速度有显著提升。