数字图书馆建设:回顾与展望   总被引：1，自引：0，他引：1  

孔慧 《中国科技信息》2006,(18):205-206

本文探讨了数字图书馆建设已取得的成绩及我国数字图书馆发展中面临的主要问题，并指出具有中国特色数字图书馆发展的基本模式。  相似文献   

模拟跨声速湍流的线性和非线性涡粘性湍流模式   总被引：1，自引：0，他引：1  

杨晓东  马晖扬 《中国科学院研究生院学报》2004,21(4):454-461

讨论应用线性和非线性涡粘性湍流模式计算跨声速湍流 .用于比较的 3个线性湍流模式是Shih和Lumley的k ε模式 ,CMOTT模式和SST模式 .2个非线性模式是Shih ,Zhu和Lumleyd的二阶模式 ,以及Shih等的三阶模式 .计算的典型流动是绕凸起的跨声速流动 ,该流动的特征是激波与边界层相互作用且伴有流动分离 .计算结果表明非线性湍流模式具有明显的优势 .  相似文献   

Endogenous technical advance and the stochastic trend in output: A neoclassical approach   总被引：2，自引：0，他引：2  

Gordon Reikard   《Research Policy》2005,34(10):1476-1490

In the recent endogenous growth literature, the trend in output is stochastic, while investment in scientific knowledge is treated as analogous to a capital stock. This paper models both research and development (R&D) and disembodied technical advance using neo-classical equations, which specify the equilibrium stocks as a function of prices and output. The elasticity of R&D in the production function, estimated using factor shares, is time-varying and increasing. Returns to scale are increasing in all factors. The most important aspect of the model is that the equilibrium rate of technical advance is not cyclically invariant, but co-moves with output at business cycle frequencies. This allows the production function to behave as a stochastic trend. Growth accounting demonstrates that long-term variations in the rate of productivity growth have been associated mainly with low-frequency fluctuations in the rate of disembodied technical advance, with secondary effects from the stocks of R&D and physical capital. During the high productivity period 1948–1972, technical advance contributed 1.48 percentage points per year to output, with 0.98 accounted for by R&D. The productivity slowdown of the mid-1970s was accounted by a gradual decline in the effect of R&D, and a more abrupt collapse in disembodied technology. The subsequent productivity revival was associated with two accelerations in disembodied technical advance, the first beginning in the early 1980s, and the second in the mid-1990s. The production function is simulated in a small econometric model. Model simulations find that exogenous shocks to the inflation rate generate significant variations in growth by inducing fluctuations in disembodied technology.  相似文献   

Effective and inclusive schools? Attention to diversity in highly effective schools in the Autonomous Region of the Basque Country     

Nahia Intxausti  Feli Etxeberria  Isabel Bartau 《International Journal of Inclusive Education》2017,21(1):14-30

This paper forms part of a research project that aims to characterise best practices in highly effective schools in the Autonomous Region of the Basque Country (ARBC). The aim is for the best practices identified to serve as points of reference when designing improvement plans to be implemented in all schools in the ARBC, with the advice and support of the education inspectorate. Highly effective schools are identified through the results of the Diagnostic Assessments carried out by the Basque Institute for Research and Evaluation in Education (ISEI-IVEI) of all primary and secondary schools in the ARBC. Multilevel statistical modelling and Hierarchical Linear Models were used to select 32 highly effective schools, with highly effective being taken to mean any school with higher-than-expected student results after adjusting for the effect of contextual factors. Eighty-three interviews were conducted with management teams, educational advisors and inspectors at each of the selected schools. This paper presents the results obtained in relation to how attention to diversity is organised. The practices identified included, among others, inclusive actions such as support teaching in ordinary classrooms, the splitting up of classroom groups, the formation of heterogeneous groups and the conceptualisation of the support provided as a shared teaching responsibility.  相似文献   

乡村旅游发展模式探讨   总被引：7，自引：0，他引：7  

蒙睿  李红  梁丹 《昆明大学学报》2006,17(2):57-59

乡村旅游是我国农村经济在新时期实现转型的重要途径之一,也是完善旅游产品、建设云南旅游经济强省的主要途径之一。本文根据乡村旅游地的市场区位特征、资源价值特征和旅游区位特征划分了四种主要的乡村旅游地类型,并针对不同发展模式的乡村旅游发展进行了探讨。  相似文献   

Automated Latent Growth Curve Model Fitting: A Segmentation and Knot Selection Approach     

Katerina M. Marcoulides 《Structural equation modeling》2018,25(5):687-699

Latent growth curve models are widely used in the social and behavioral sciences to study complex developmental patterns of change over time. The trajectories of these developmental patterns frequently exhibit distinct segments in the studied variables. Latent growth models with piecewise functions for repeated measurements of variables have become increasingly popular for modeling such developmental trajectories. A major problem with using piecewise models is determining the precise location of the point where the change in the process has occurred and uncovering the related number of segments. The purpose of this paper is to introduce an optimization procedure that can be used to determine both the segments and location of the knots in piecewise linear latent growth models. The procedure is illustrated using empirical data in order to detect the number of segments and change points. The results demonstrate the capabilities of the procedure for fitting latent growth curve models.  相似文献   

Examining Chi-Square Test Statistics Under Conditions of Large Model Size and Ordinal Data     

Dexin Shi  Christine DiStefano  Heather L. McDaniel  Zhehan Jiang 《Structural equation modeling》2018,25(6):924-945

This study examined the effect of model size on the chi-square test statistics obtained from ordinal factor analysis models. The performance of six robust chi-square test statistics were compared across various conditions, including number of observed variables (p), number of factors, sample size, model (mis)specification, number of categories, and threshold distribution. Results showed that the unweighted least squares (ULS) robust chi-square statistics generally outperform the diagonally weighted least squares (DWLS) robust chi-square statistics. The ULSM estimator performed the best overall. However, when fitting ordinal factor analysis models with a large number of observed variables and small sample size, the ULSM-based chi-square tests may yield empirical variances that are noticeably larger than the theoretical values and inflated Type I error rates. On the other hand, when the number of observed variables is very large, the mean- and variance-corrected chi-square test statistics (e.g., based on ULSMV and WLSMV) could produce empirical variances conspicuously smaller than the theoretical values and Type I error rates lower than the nominal level, and demonstrate lower power rates to reject misspecified models. Recommendations for applied researchers and future empirical studies involving large models are provided.  相似文献   

阅读模式及其对英语阅读教学的启示     

汪精玲 《伊犁师范学院学报》2001,(1):53-56

介绍了现代语言心理学关于四种阅读模式的研究，进而从阅读能力，阅读策略，阅读图式，阅读情境四个方面，探讨了英语阅读教学观念和方法的更新。  相似文献   

国际教师专业标准的三种模式及启示   总被引：11，自引：0，他引：11  

施克灿 《比较教育研究》2004,25(12):81-85

教师专业化是国际教师教育发展的必然趋势.从某种意义上说,教师专业化既是一种目的,是教师教育所要追求的目标;也可以说是一种过程,即培养教师使其达到专业所要求标准的过程,而教师专业标准的模糊或缺失必然导致教师专业化发展方向的迷失.本文主要围绕国际上三种模式的教师专业标准,分析其内容及主要特征,在此基础上,提出我国建立教师专业标准的政策建议,以全面提高我国教师培养培训的质量.  相似文献   

电动服装裁剪机的振动模态测试     

赵阳 《大连大学学报》1997,(2)

用锤击激振实验测试方法测得了服装剪裁机存在的三种振动类型和六种振动模态,为改进其动态性能提供了依据和有益的参考。  相似文献