共查询到20条相似文献，搜索用时 187 毫秒
1.
我国省级区域产业相对比较优势研究 总被引：1，自引：0，他引：1
提出了以无量纲的产业增加值占地区生产总值的比重作为比较依据的区域产业相对比较优势〔度〕的概念和计算方法,并用2004年中国大陆各省区的产业统计数据进行计算分析。结果表明,中国大陆各省区的产业相对比较优势〔度〕排序与产业规模排序有很大差异,与报后者排序相比,不少中西部经济欠发达省区的第一、第二和第三产业及其下属各个分行业的相对比较优势〔度〕排序明显靠前,这为中西部经济欠发达省区的经济发展战略和主导产业选择提供一种新的参考依据。 相似文献
2.
何洪英 《绵阳师范学院学报》2007,26(11):98-100
介绍了两种较为成熟的排序方法冒泡法和选择排序法,指出这两种排序方法都可在原来基础上实现双向排序。并以选择排序法为例,给出了新算法的算法思想、算法描述和算法的程序实现。通过分析算法的比较次数和移动次数得出结论:新算法和传统的排序算法方法同样简单,但排序效率相同甚至更高,均可作为实际排序和教学过程中的思路参考。 相似文献
3.
徐寿芳 《湖州职业技术学院学报》2008,6(1):17-19
排序是数据处理中一种很重要拘运算,能够方便数据的查找。常用内排序算法时间复杂度接近O（n^2）,优化的排序算法接近O（nlog2n）。基于基数排序的新排序方法,通过对关键字的低半部和高半部做两次基数排序,快速实现排序功能。最后给出了新排序算法和常用排序算法的数据排序效率比较,实验证明,它可以使算法的时间复杂度达到O（N）,算法的效率远远高于常规的排序算法。 相似文献
4.
排序在数据处理中占有极重要的位置,排序算法的好坏,直接影响到实现的复杂度。本文介绍了常用的排序算法,并详细讨论了冒泡排序法的实现、改进和时间复杂度。 相似文献
5.
曾棕根 《宁波职业技术学院学报》2006,10(5):83-85
提出了除升序排序、降序排序之外的第三种排序——随机排序,并将随机排序分为完全随机排序和不完全随机排序两类,最后,进述了随机排序在VisualBasic6和C 下的算法实现及随机排序算法在大规模准考证生成中的应用实例。 相似文献
6.
基于直觉模糊熵提出了一种分析直觉模糊评价矩阵决策问题的新方法。利用直觉模糊熵定义指标权重矩阵,指标权重矩阵行向量满足概率分布公理化定义,结合相对熵优化模型得到了指标权重的最优解;通过专家提供的信息量结合相对熵模型得到专家客观权重,最后利用模糊互补判断矩阵与相对熵模型实现了备选方案之间的最优排序,最后给出一个实例,说明该方法的可行性和优越性。 相似文献
7.
排序是计算机科学中最重要的研究问题之一,也是学习C语言程序设计过程中重点研究问题之一。主要介绍了顺序比较法、选择排序法、冒泡排序法、改进的冒泡排序法和直接插入排序法,并从排序算法的思想、模拟排序执行过程、实现排序的算法代码及算法性能分析4个方面进行了详细的解析,可以帮助C语言初学者轻松理解几种常用的排序算法。 相似文献
8.
讨论了AOV网的一种并行性全拓扑排序的算法及实现,解决了传统拓扑排序算法的单一性问题,说明了并行全拓扑排序有重要的实用价值。 相似文献
9.
排序在数据处理中占有极重要的位置,排序算法的好坏,直接影响到实现的复杂度.本文介绍了常用的排序算法,并详细讨论了冒泡排序法的实现、改进和时间复杂度. 相似文献
10.
排序是计算机数据处理中的一项重要操作,通过排序可以提高查找的效率。用计算机处理的很多问题的关键在于如何排序,因此熟练地掌握一些基本的排序方法就显得非常重要。插入法排序是基本排序算法中的一种。本文用C#2005编程实现了该排序算法的动态演示,非常直观,有助于初学者快速掌握和了解这一算法的基本原理和具体实现过程。 相似文献
11.
欧几里得在古希腊时期用反证法证明了在自然数序列中存在无穷多个素数,本文是该命题的一种推广.注意到自然数序列是一个首项为1公差为1的等差数列,本文证明把公差1换做任意一个正整数,保持首项为1不变,则得到的等差数列中仍然存在无穷多个素数. 相似文献
12.
Traditionally measured skills with arithmetic are not related to later algebra success at levels that would be expected given the close conceptual relation between arithmetic and algebra. However, adaptivity with arithmetic may be one aspect of arithmetic competences that can account for additional variation in algebra attainment. With this in mind, the present study aims to present evidence for the existence and relevance of a newly acknowledged component of adaptivity with arithmetic, namely, adaptive number knowledge. In particular, we aim to examine whether there are substantial individual differences in adaptive number knowledge and to what extent these differences are related to arithmetic and pre-algebra skills and knowledge. Adaptive number knowledge is defined as the well-connected knowledge of numerical characteristics and relations. A large sample of 1065 Finnish late primary school students completed measures of adaptive number knowledge, arithmetic conceptual knowledge, and arithmetic fluency. Three months later they completed a measure of pre-algebra skills. Substantial individual differences in adaptive number knowledge were identified using latent profile analysis. The identified profiles were related to concurrent arithmetic skills and knowledge. As well, adaptive number knowledge was found to predict later pre-algebra skills, even after taking into account arithmetic conceptual knowledge and arithmetic fluency. These results suggest that adaptive number knowledge is a relevant component of mathematical development, and may help account for disparities in algebra development. 相似文献
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刘元宗 《洛阳师范学院学报》2012,(2):21-25
本文通过对"吉祥数"研究,发现各位"吉祥数"的个数数列与杨辉三角密切相关,并且正整数的各位"吉祥数"的个数数列是高阶等差数列,因此"吉祥数"问题可应用高阶等差数列的相关知识来解决. 相似文献
15.
由于IEEE754标准的浮点数在计算机中是以原码的格式存储的,为了将浮点运算的结果转换成原码,最快的方法是使用反码运算系统。试应用超前进位和反码运算系统原理设计了单精度浮点数的快速的阶码减法器和尾数加法器/减法器。 相似文献
16.
郭龙先 《昭通师范高等专科学校学报》2011,33(5)
西帕索斯最早证明了不可公度线段的存在,其长度就是一个无理数．古希腊几何学家却拒绝承认无理数是数,导致了希腊数学由算术向几何学的转向,并由此推动了公理化思想的发展,使数学的严密性达到了更高的境界．因为放弃了对无理数的研究,致使算术和代数的发展受到限制,几何学畸形发展的局面在欧洲持续了两千多年． 相似文献
17.
Adaptive expertise is a valued, but under-examined, feature of students' mathematical development (e.g. Hatano & Oura, 2012). The present study investigates the nature of adaptive expertise with rational number arithmetic. We therefore examined 394 7th and 8th graders’ rational number knowledge using both variable-centered and person-centered approaches. Performance on a measure of adaptive expertise with rational number arithmetic, the arithmetic sentence production task, appeared to be distinct from more routine features of performance. Even among the top 45% of students, all of whom had strong routine procedural and conceptual knowledge, students varied greatly in their performance the arithmetic sentence production task. Strong performance on this measure also predicted later algebra knowledge. The findings suggest that it is possible to distinguish adaptive expertise from routine expertise with rational numbers and that this distinction is important to consider in research on mathematical development. 相似文献
18.
旦志红 《乌鲁木齐成人教育学院学报》2006,14(2):59-61
在由相对数或平均数求平均数时,可以以这一相对数或平均数的分母或分子为权数,对这一相对数或平均数进行加权,利用加权算数平均数的频数公式或加权调和平均数公式求其平均值。 相似文献
19.
Fiona R. Simmons Chris Singleton 《Journal of Research in Special Educational Needs》2009,9(3):154-163
This paper reports the findings of two related studies that examined the mathematical strengths and weaknesses of children with dyslexia. In study one, dyslexic children were compared to children without special educational needs on tests that assessed arithmetic fact recall, place value understanding and counting speed. Study two used the same methodology, but matched the dyslexic children with the non‐dyslexic children on a number of factors, including intellectual ability. This excluded the possibility that confounding variables accounted for the differences between the groups in study one. Both studies indicated that the dyslexic children had slower and less accurate number fact recall than the non‐dyslexic children, but had unimpaired place value understanding. The results for counting speed were more equivocal, but there was a trend for the dyslexic children to be slower counters. The results suggest that dyslexia is not normally associated with a general mathematical impairment, but rather an uneven profile of skills. This profile can be explained in terms of the phonological processing weaknesses associated with dyslexia. The finding that dyslexic children have a specific difficulty recalling arithmetic facts suggests that a teaching programme that emphasises mental methods may disadvantage them. 相似文献
20.
Basic numerical skills provide an important foundation for the learning of mathematics. Thus, it is critical that researchers and educators have access to valid and reliable ways of assessing young children's numerical skills. The purpose of this study was to evaluate the concurrent, predictive, and incremental validity of a two-minute paper-and-pencil measure of children's symbolic (Arabic numerals) and non-symbolic (dot arrays) comparison skills. A sample of kindergarten children (Mage = 5.86, N = 439) were assessed on the measure along with a number line estimation task, a measure of arithmetic, and several control measures. Results indicated that performance on the symbolic comparison task explained unique variance in children's arithmetic performance in kindergarten. Longitudinal analyses demonstrated that both symbolic comparison and number line estimation in kindergarten were independent predictors of 1st grade mathematics achievement. However, only symbolic comparison remained a unique predictor once language skills and processing speed were taken into account. These results suggest that a two-minute paper-and-pencil measure of children's symbolic number comparison is a reliable predictor of children's early mathematics performance. 相似文献