首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 391 毫秒
1.
Murad Jurdak 《ZDM》2014,46(7):1025-1037
This paper aims at identifying and understanding how and to what extent socioeconomic and cultural factors mediate mathematics achievement and between-school equity in mathematics education among countries. First, under the assumption that equity and quality of education are independent constructs, the construct of equity-in-quality in mathematics education is developed. Second, the 18 countries that were identified in the previous work of the author Jurdak in (Toward equity in quality in mathematics education. Springer, New York, 2009) as being diverse in mathematics education will serve as study cases to illustrate, compare, and contrast the mediatory role of socio-economic and cultural factors in mathematics achievement and between-school equity in mathematics education. The results show that the differences in mathematics achievement and between-school equity in mathematics education at the country level are associated with, and can be accounted for in some cases, by socioeconomic and cultural factors.  相似文献   

2.
We introduce a theory of scan statistics on graphs and apply the ideas to the problem of anomaly detection in a time series of Enron email graphs. Previous presentation: Workshop on Link Analysis, Counterterrorism and Security at the SIAM International Conference on Data Mining, Newport Beach, CA, April 23, 2005. Carey E. Priebe received the B.S. degree in mathematics from Purdue University in 1984, the M.S. degree in computer science from San Diego State University in 1988, and the Ph.D. degree in information technology (computational statistics) from George Mason University in 1993. From 1985 to 1994 he worked as a mathematician and scientist in the US Navy research and development laboratory system. Since 1994 he has been a professor in the Department of Applied Mathematics and Statistics, Whiting School of Engineering, Johns Hopkins University, Baltimore, Maryland. At Johns Hopkins, he holds joint appointments in the Department of Computer Science and the Center for Imaging Science. He is a past President of the Interface Foundation of North America—Computing Science & Statistics, a past Chair of the Section on Statistical Computing of the American Statistical Association, and on the editorial boards of Journal of Computational and Graphical Statistics, Computational Statistics and Data Analysis, and Computational Statistics. His research interests are in computational statistics, kernel and mixture estimates, statistical pattern recognition, statistical image analysis, and statistical inference for high-dimensional and graph data. He was elected Fellow of the American Statistical Association in 2002. John M. Conroy received a B.S. in Mathematics from Saint Joseph's University in 1980 and a Ph.D. in Applied Mathematics from the University of Maryland in 1986. Since then he has been a research staff member for the IDA Center for Computing Sciences in Bowie, MD. His research interest is applications of numerical linear algebra. He is a member of the Society for Industrial and Applied Mathematics, Institute of Electrical and Electronics Engineers (IEEE), and the Association for Computational Linguistics. David J. Marchette received a B.A. in 1980, and an M.A. in mathematics in 1982, from the University of California at San Diego. He received a Ph.D. in Computational Sciences and Informatics in 1996 from George Mason University under the direction of Ed Wegman. From 1985–1994 he worked at the Naval Ocean Systems Center in San Diego doing research on pattern recognition and computational statistics. In 1994 he moved to the Naval Surface Warfare Center in Dahlgren Virginia where he does research in computational statistics and pattern recognition, primarily applied to image processing, text processing, automatic target recognition and computer security. Dr. Marchette is a Fellow of the American Statistical Society. Youngser Park received the B.E. degree in electrical engineering from Inha University in Korea in 1985, the M.S. degree in computer science from The George Washington University in 1991, and had pursued a doctoral degree there. From 1998 to 2000 he worked at the Johns Hopkins Medical Institutes as a senior research engineer. Since 2003 he is working as a research analyst in the Center for Imaging Science at the Johns Hopkins University. His research interests are clustering algorithm, pattern classification, and data mining.  相似文献   

3.
Jaguthsing Dindyal 《ZDM》2008,40(6):993-1005
This paper highlights the gender factor in the Trends in Mathematics and Science Study in 2003 (TIMSS-2003) of eight participating countries from the Asia-Pacific region: Chinese Taipei, Hong Kong-SAR, Indonesia, Japan, Republic of Korea, Malaysia, Singapore, and the Philippines (Chinese Taipei and Hong Kong-SAR will be referred to as countries in this paper.) in mathematics. The focus is on gender-related data encompassing the overall performance of students from the participating countries and their performance in the content and cognitive domains. At grade 8 level, the gender difference in the overall performance of students mirrored the international average and favored girls in all countries of the Asia-Pacific region (except in Japan and the Republic of Korea). The regional data also showed that, in general, the Philippines and Singapore can be considered to be at one extreme with gender differences favoring girls in both content and cognitive domains, and the Republic of Korea and to some extent Japan are at the other extreme with the gender differences favoring boys. At grade 4 level, girls from the Philippines and Singapore also performed better than the boys whereas the boys from Japan and Chinese Taipei did slightly better than the girls.  相似文献   

4.
推进成渝地区双城经济圈建设已经上升为国家发展战略.以交通物流基础设施建设为例,从个体理性和团体理性两个方面,对竞争状态、合作状态和混合状态三种情况分别构建博弈关系模型并求解,得出结论:在成渝地区双城经济圈建设交通物流基础设施的过程中,核心城市的个体利益大于团体利益,表现为个体理性与团体理性之间的冲突,即两者存在非合作博弈关系.最后针对核心城市存在的非合作博弈关系,提出促进成渝地区双城经济圈核心城市协同发展的对策建议.  相似文献   

5.
该文系统地介绍随机环境中的马尔可夫过程. 共4章, 第一章介绍依时的随机环境中的马尔可夫链(MCTRE), 包括MCTRE的存在性及等价描述; 状态分类; 遍历理论及不变测度; p-θ 链的中心极限定理和不变原理. 第二章介绍依时的随机环境中的马尔可夫过程(MPTRE), 包括MPTRE的基本概念; 随机环境中的q -过程存在唯一性; 时齐的q -过程;MPTRE的构造及等价性定理.第三章介绍依时的随机环境中的分枝链(MBCRE), 包括有限维的和无穷维的MBCRE的模型和基本概念; 它们的灭绝概念;两极分化; 增殖率等.第四章介绍依时依空的随机环境中的马尔可夫链(MCSTRE), 包括MCSTRE的基本概念、构造; 依时依空的随机环境中的随机徘徊(RWSTRE)的中心极限定理、不变原理.  相似文献   

6.
University education for operational research in Britain is making great and welcome strides forward, but there has been little open discussion of its aims in relation to the advance of the profession. Progress in operational research, and in its application to the really worth-while problems of industry in particular, depends primarily on strengthening the industrial operational research group in its “front line” role. We need a research study of the teaching and practice of industrial operational research, in relation to effectiveness. We need “collaborative” programmes of operational research education in which the university and the industrial operational research group each contribute, in a man's training over a period of years, in the ways in which each is most competent. We need emphasis on “breadth” as well as “depth” in operational research education, and greater attention to the mutual contributions of operational research, teaching and practice, and the teaching and development of management. An impressionist sketch of a programme which might meet these needs is put forward for discussion of principles and feasibility.  相似文献   

7.
结合大庆油田物资公司在重要供应链管理环节,即采购、需求和库存中所面临的实际问题(物资需求增加、仓储压力增大、采购成本增多)及三者之间的相互作用,基于预测和优化理论,构建了针对油田A类物资的采购优化和库存管理决策支持系统原型,包括:预测模块、优化模块和方案调整评估模块,为相关部门制定合理物资采购方案提供决策支持.进一步,以银浪仓库中的4种A类物资为例,运用该原型系统进行数值模拟. 结果表明,2009年和2010年4种物资的总成本节省率分别为10.35%和8.07%,效益可观. 考虑到油田物资数据结构不完备及优化模型的复杂性,该原型系统在大庆油田大规模推广方面仍需进一步完善.  相似文献   

8.
Keith Jones  Taro Fujita 《ZDM》2013,45(5):671-683
This paper reports on how the geometry component of the National Curricula for mathematics in Japan and in one selected country of the UK, specifically England, is interpreted in school mathematics textbooks from major publishers sampled from each country. The findings we report identify features of geometry, and approaches to geometry teaching and learning, that are found in a sample of textbooks aimed at students in Grade 8 (aged 13–14). Our analysis raises two issues which are widely recognised as very important in mathematics education: the teaching of mathematical reasoning and proof, and the teaching of problem-solving. In terms of the teaching of mathematical reasoning and proof, our evidence indicates that this is dispersed in the textbook in England while it is concentrated in geometry in the textbook in Japan. In terms of the teaching of mathematical problem-solving and modeling, our analysis shows that it is more concentrated in the textbook from England, and rather more dispersed in the textbook from Japan. These findings indicate how important it is to consider ways in which these issues can be carefully designed in the geometry sections of future textbooks.  相似文献   

9.
It is a well‐known fact that, in general, many students have a lack of interest and proficiency in mathematics and science. Therefore, it is imperative that we prepare and inspire all students, specifically students of underrepresented populations, to learn science, technology, engineering, and mathematics (STEM) content. Now in its fourth year, See Blue STEM Camp was created in order to expose middle‐level students to a variety of STEM fields and STEM professionals through hands‐on project‐based learning experiences in order to increase their interest in STEM. This paper describes the structure and the activities of the camp. In this innovative project, we utilized an embedded mixed methods study design to investigate the extent middle level students' attitudes, perceptions, and interest in and toward STEM fields and careers changed after participating in an informal learning environment of a five‐day day camp held on the campus of a major university in the mid‐south. The results revealed an increase in their motivation and interest in STEM fields; in fact, there was 3% increase from pre to post in interest in STEM careers. The data also revealed that a majority of the participating middle school students found the STEM content sessions “fun” and engaging, specifically citing the hands‐on experiences they received.  相似文献   

10.
创业企业家和风险投资家因为控制权模式不合理所导致的矛盾在我国普遍存在。为解决该问题,本文通过研究创业企业家与风险投资家在博弈过程中的控制权策略选择及由此决定的控制权模式,运用演化博弈理论中复制动态的方法分析发现:(1)创业企业家和风险投资家在选择是否争取控制权的博弈结果是联合控制或相机控制;(2)项目成功概率、风险投资家获取的剩余索取权增加时收敛于联合控制,反之则收敛于相机控制;当项目成功的概率大于50%时,固定收益减少收敛于联合控制,创业企业产出增加收敛于联合控制,反则收敛于相机控制。最后,通过CV Source数据库样本数据对模型结论进行了实证检验,检验结果与理论模型的主要结论相一致。研究结论对于指导我国创业企业控制权模式合理选择具有一定的实践意义。  相似文献   

11.
中国对外贸易发展成熟、国际地位显著,但从长期看,其边际收益呈现递减趋势.而对外直接投资虽规模较小,且尚在起步阶段,但其发展速度快、市场潜力巨大.在拓展Anderson和Wincoop模型基础上,理论分析了对外直接投资与贸易之间的关系.然后通过建立计量模型,利用1995-2011年面板数据进行固定模型分析.由于中国对外直接投资的贸易效应存在明显的区域性,以北美自贸区、欧盟和东盟作为研究对象,实证检验了中国对外直接投资与贸易的关系,旨在考察中国对三种不同类型区域一体化组织投资的贸易效应差异.研究结果表明,从长期看,中国对北美自由贸易区、欧盟和东盟投资均具有明显的贸易创造效应.这种贸易创造效应的大小依次是东盟欧盟北美自贸区.  相似文献   

12.
In supply chain co-opetition, firms simultaneously compete and co-operate in order to maximize their profits. We consider the nature of co-opetition between two firms: The product supplier invests in the technology to improve quality, and the purchasing firm (buyer) invests in selling effort to develop the market for the product before uncertainty in demand is resolved. We consider three different decision making structures and discuss the optimal configuration from each firm’s perspective. In case 1, the supplier invests in product quality and sets the wholesale price for the product. The buyer then exerts selling effort to develop the market and following demand potential realization, sets the resale price. In case 2, the supplier invests in product quality followed by the buyer’s investment in selling effort. Then, after demand potential is observed, the supplier sets the wholesale price and the buyer sets the resale price. Finally, in case 3, both firms simultaneously invest in product quality and selling effort, respectively. Subsequently, observing the demand potential, the supplier sets the wholesale price and the buyer sets the resale price. We compare all configuration options from both the perspective of the supplier and the buyer, and show that the level of investment by the firms depends on the nature of competition between them and the level of uncertainty in demand. Our analysis reveals that although configuration 1 results in the highest profits for the integrated channel, there is no clear dominating preference on system configuration from the perspective of both parties. The incentives of the co-opetition partners and the investment levels are mainly governed by the cost structure and the level of uncertainty in demand. We examine and discuss the relation between system parameters and the incentives in desiging the supply contract structure.  相似文献   

13.
Gas thrust bearings are often used in low-load applications, e.g. in air cycle machines, in micro gas turbines or in rotor systems for fuel cell applications, to support a shaft in axial direction. The pressure and temperature distribution in a gas thrust bearing pad are described by the generalized Reynolds equation according to Dowson and the 3D energy equation. In this paper, two different approaches are presented in order to reduce the dimension of the governing nonlinear integro-differential equation system and in order to stabilize the solution process. In the first reduction approach, the temperature in the fluid is averaged across the fluid film according to Lee and Kim. In the second approach, Legendre polynomials are used to approximate temperature, density and fluidity across the fluid film according to Elrod, Brewe and Moraru. The reduction techniques are compared with respect to numerical efficiency, accuracy and convergence behavior. (© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

14.
We introduce some basic concepts such as random (sub-)transition function, q-function in random environment, g-process in random environment and some basic lemmas. For any continuous g-function in random environment, we prove that the g-process in random environment always exists, and that any g-process in random environment satisfies the random Kolmogorov backward equation and the minimal g-process in random environment always exists. When g is a continuous and conservative g-function in random environment, the necessary and sufficient conditions for the uniqueness of g-process in random environment are given. Finally the special cases, homogeneous random transition functions and homogeneous g-processes in random environments are considered.  相似文献   

15.
Students’ mathematical achievement in Iceland, as reported in PISA 2003, showed significant and (by comparison) unusual gender differences in mathematics: Iceland was the only country in which the mathematics gender gap favored girls. When data were broken down and analyzed, the Icelandic gender gap appeared statistically significant only in the rural areas of Iceland, suggesting a question about differences in rural and urban educational communities. In the 2007 qualitative research study reported in this paper, the authors interviewed 19 students from rural and urban Iceland who participated in PISA 2003 in order to investigate these differences and to identify factors that contributed to gender differences in mathematics learning. Students were asked to talk about their mathematical experiences, their thoughts about the PISA results, and their ideas about the reasons behind the PISA 2003 results. The data were transcribed, coded, and analyzed using techniques from analytic induction in order to build themes and to present both male and female student perspectives on the Icelandic anomaly. Strikingly, youth in the interviews focused on social and societal factors concerning education in general rather then on their mathematics education.  相似文献   

16.
The noise involved in protein circuit can result in fluctuations in protein concentrations. Then we have explored the effect of such noise on the feedback loop between p53 and its repressor Mdm2, the negative feedback dynamics and oscillatory activities are presented. Recent experimental results show that under certain conditions, the activity of the average protein level of p53 behaves with dampened oscillation in response to DNA damage, and it has non-decaying oscillatory behavior in individual cells, and we show that the dampening is induced by intrinsic noise, namely the uncertainty associated with chemical kinetics in dealing with when and in what order reactions take place in the p53 system. Furthermore, the experimental results are reproduced in this paper.  相似文献   

17.
Many studies (such as Pepin in Learners and pedagogy, Sage Publications, London, 1999; Kaiser in ZDM 34(6):241–257, 2002; Park and Leung in Mathematics education in different cultural traditions: a comparative study of East Asia and the West. The 13th ICMI Study, pp. 227–238, Springer, New York, 2006) have revealed that there is a strong dependence on cultural traditions in mathematics teaching in different countries. Education in Germany is influenced by the Central and North European Didaktik tradition (Westbury in Teaching as a reflective practice: the German Didaktik tradition, L. Erlbaum Associates, Mahwah, pp. 15–39, 2000), while that in East Asia is influenced by Confucian heritage culture. However, there have not been studies investigating the relationships between these two cultural traditions and their influences on teaching and learning. This study aims at filling this gap in knowledge. Some commonalities in the aims and beliefs in the underlying philosophies in education in traditional China and Germany were found and are presented in this paper. Specifically, the relationship between cultural traditions and the implemented mathematics curriculum was investigated, using Berlin and Hong Kong as examples. It was found that culture affects the implemented curriculum in a complicated way and that other factors such as the intended curriculum and textbooks may also influence the implemented curriculum.  相似文献   

18.
目前,研究生教育处于我国高等教育的最高层次,肩负着为国家发展培养高技术专业型人才的重要任务.尤其是在各国竞争愈发激烈的今天,理工类研究生更是在未来国家现代化建设、科技创新中发挥着重要作用.但是,由于近几年研究生招生规模的逐渐扩大,研究生的培养模式、培养质量等方面出现了许多亟待解决的问题.从商科型高校理工类研究生的培养现状出发,通过运用文献法和归纳法,本文对当前研究生培养过程中存在的问题进行分析,并针对学生创新能力的培养,从学校、导师和学生自身三方面给出了相应的解决措施,着重强调了数学建模在理工类研究生创新能力培养过程中所发挥的重要作用.最后,以湖南工商大学近几年在理工类研究生创新能力培养实践中所采取的主要举措以及取得的成效来进一步论证本文所提出措施的有效性.  相似文献   

19.
The problem of modelling the motion of a force disturbance in an elastic medium that is heterogeneous over its depth is investigated. It is in an antiplane formulation in a moving system of coordinates that all possible versions of the ratio of the velocity of motion of the surface point shear load to the velocities of the shear waves in the layers of the two-layer elastic base are examined. Cases of a subsonic regime (SBR) in the upper and lower layers, of a supersonic regime (SPR) in the upper layer and an SBR in the lower layer, and of an SBR in the upper layer and an SPR in the lower layer are studied using the Fourier transform and the theory of residues. The last two cases are extremely interesting from the mathematical point of view, as here, on the boundary between the layers, the solutions of elliptic and hyperbolic equations meet, and previously unknown features arise in the displacements that,it seems, should also occur in the solution of the corresponding plane problem. The case of an SPR in the upper and lower layers is investigated using a special method for successive allowance for the incident, reflected and refracted shock wave fronts. In all cases, expressions are obtained for the displacements in the layers, and their characteristic features are investigated.  相似文献   

20.
The key issues of community operational research, outlined in a paper by Ritchie, have relevance to community projects in general and, we argue, a particular relevance to public art. We illustrate this relevance by describing eight case studies in public art, four in Japan and four in the west, and by considering the projects in a three-way factorial design, make a case for the art director system in the management of public art projects.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号