科研信息化基础设施的大数据挑战

首先探讨大数据科学（Big Data Science）给现代和未来科研数据基础设施（SDI）带来的挑战,并参考不 同科研团体的工作对数据管理、访问控制和安全要求进行定义,然后介绍科研数据生命周期管理（SDLM）模型,分析 所有的主要阶段,反映现代e-Science的数据管理特性,提出SDI 通用架构模型,为利用现代技术和最佳实践构建以互 用性数据或项目为中心的SDI 奠定了基础,最后对如何利用基于云的现代基础设施服务配置模型顺利实现文中提出的 SDLM和SDI 模型进行阐述,解决SDI 资源的联合访问控制问题,为科研团体提供了一种灵活的访问控制和身份管理模 型。     

Constructivism: Defense or a Continual Critical Appraisal A Response to Gil-Pérez et al.

This commentary is a critical appraisal of Gil-Pérez et al.'s (2002) conceptualization of constructivism. It is argued that the following aspects of their presentation are problematic: (a) Although the role of controversy is recognized, the authors implicitly subscribe to a Kuhnian perspective of `normal' science; (b) Authors fail to recognize the importance of von Glasersfeld's contribution to the understanding of constructivism in science education; (c) The fact that it is not possible to implement a constructivist pedagogy without a constructivist epistemology has been ignored; and (d) Failure to recognize that the metaphor of the `student as a developing scientist' facilitates teaching strategies as students are confronted with alternative/rival/conflicting ideas. Finally, we have shown that constructivism in science education is going through a process of continual critical appraisals.     

Metabolic cost of stride rate, resistance, and combined use of arms and legs on the elliptical trainer

We measured the effects of stride rate, resistance, and combined arm-leg use on energy expenditure during elliptical trainer exercise and assessed the accuracy of the manufacturer's energy expenditure calculations. Twenty-six men and women (M age = 29 years, SD = 8; M body weight = 73. 0 kg, SD = 15.2) participated. Twenty-two participants performed two tests, one without the arm poles (leg-only) and the other with arm poles (combined arm-leg). The other 4 participants performed one test without the arm poles. Both tests consisted of six 5-min stages (two stride rates, 110 and 134 stridesmin-1, and three resistance settings: 2, 5, and 8). Steady-state oxygen uptake (VO2), minute ventilation (VE), heart rate (HR) and rating of perceived exertion (RPE) were measured. Repeated measures analysis of variance determined higher (p <. 001) VO2, VE, and RPE, but not HR, during combined arm-leg versus leg-only exercise at any given intensity. Increases in stride rate and resistance increased VO2, VE, RPE, and HR with the greatest effect on VE and HR from Levels 5 to 8. The manufacturer's calculated energy expenditure was overestimated during both tests. Although the oxygen cost for elliptical trainer exercise was calculated to be approximately 0.1 mlxkg(-1) per stride and 0.7 mlxkg(-1) min-1 per resistance level, VO2 varied widely among individuals, possibly due to differences in experience using the elliptical trainer gender, and body composition. The elliptical trainer offers (a) a variety of intensities appropriate for most individuals and (b) both arm and leg exercise. Due to the wide variability in VO2, predicting the metabolic cost during elliptical trainer exercise for an individual is not appropriate.     

Does the individual zones of optimal functioning model discriminate between successful and less successful athletes? A meta-analysis

According to the individual zones of optimal functioning (IZOF) model, an athlete's performance is successful when his or her pre-competition anxiety is within or near the individually optimal zone. When anxiety falls outside the optimal zone, performance deteriorates. The model also suggests that skilled athletes are aware of, and are able to accurately recall and anticipate, their pre-competition anxiety. A meta-analysis of 19 studies from 1978 to 1997 (146 effect sizes based on 6387 participants) was conducted to examine the validity of the assumptions regarding the in-out of the zone notion and the accuracy of recalls and anticipatory measures of anxiety. The findings provide fairly good empirical support for the IZOF anxiety model, with an overall effect size (d) for the in-out of the zone notion of d = +0.44 (41 effect sizes, n = 3175). In other words, the performance of athletes who were within their individually optimal zones were almost one-half a standard deviation unit better than that of athletes who were outside their zones. Furthermore, both effect sizes (r(w)) for accuracy of precompetition anxiety measures, recall (r(w) = +0.71, 24 effect sizes, n = 369) and anticipatory (r(w) = +0.69, 81 effect sizes, n = 2843), exceeded the 'large effect' suggested for correlations by Cohen. The implications for future research extending the IZOF model to a wider range of positive and negative emotions are discussed.     

Sparsity and Independence: Balancing Two Objectives in Optimization for Source Separation with Application to fMRI Analysis

Because of its wide applicability in various disciplines, blind source separation (BSS), has been an active area of research. For a given dataset, BSS provides useful decompositions under minimum assumptions typically by making use of statistical properties—types of diversity—of the data. Two popular types of diversity that have proven useful for many applications are statistical independence and sparsity. Although many methods have been proposed for the solution of the BSS problem that take either the statistical independence or the sparsity of the data into account, there is no unified method that can take into account both types of diversity simultaneously. In this work, we provide a mathematical framework that enables direct control over the influence of these two types of diversity and apply the proposed framework to the development of an effective ICA algorithm that can jointly exploit independence and sparsity. In addition, due to its importance in biomedical applications, we propose a new model reproducibility framework for the evaluation of the proposed algorithm. Using simulated functional magnetic resonance imaging (fMRI) data, we study the trade-offs between the use of sparsity versus independence in terms of the separation accuracy and reproducibility of the algorithm and provide guidance on how to balance these two objectives in real world applications where the ground truth is not available.     

Evaluation of Energy Saving Operational Modes for Industrial Fracture Connected Processes on the Basis of Incubation Time Fracture Criterion

A problem for a central crack in a plate subjected to plane strain conditions is investigated.Mode Ⅰ crack loading is created by a dynamic pressure pulse applied at a large distance from the crack.It was found that for a certain combination of amplitude and duration of the pulse applied,the energy transmitted to the sample has a strongly marked minimum,meaning that with the pulse amplitude or duration moving away from the optimal values,minimum energy required for initiation of crack growth increases rapidly.The results obtained indicate a possibility to optimise energy consumption of different industrial processes connected with fracture.Much could be gained in,for example,drilling or rock pounding where energy input accounts for the largest part of the process cost.Presumably further investigation of the effect observed can make it possible to predict optimal energy saving parameters,i.e.frequency and amplitude of impacts,for industrial devices,e.g.bores,grinding machines,and hence significantly reduce the process cost.The prediction can be given based on the parameters of the media fractured (material parameters,prevalent crack length and orientation,etc.).     

Using scenarios to design complex technology-enhanced learning environments

Science Created by You (SCY) learning environments are computer-based environments in which students learn about science topics in the context of addressing a socio-scientific problem. Along their way to a solution for this problem students produce many types of intermediate products or learning objects. SCY learning environments center the entire learning process around creating, sharing, discussing, and re-using these learning objects. This instructional approach requires dedicated instructional designs, which are supplied in the form of what are called pedagogical scenarios. A SCY pedagogical scenario presents the learning process as an organized assembly of elementary learning processes, each associated with a specific learning object and a tool for creating this learning object. Designing a SCY learning environment is basically a two-step procedure: the first step is to select one of the available scenarios, and the second step is to define the domain content. The SCY technical infrastructure then handles the instantiation of the scenario as a SCY computer-based learning environment. In this article we describe the SCY pedagogical design scenarios and report on our experiences in designing four different SCY learning environments.