基于γ-散度的稳健有序误标记logistic回归

有序多分类方法已经得到了广泛研究。传统的有序多分类方法假设样本的类别标签是不存在误标记的。但是由于实际数据复杂以及人工经验有限,获得标记完全正确的样本是不现实的,因此,传统的方法就存在局限性。提出一种基于γ-散度的有序误标记logistic回归方法,在处理存在误标记的有序多分类问题时具有很强的稳健性,也就是说,当某一样本被错误标记时它对参数估计的权重小于其被正确标记时的权重。该方法通过最小化γ-散度构建模型,利用梯度下降算法求解模型,不仅具有很强的稳健性而且在模型中可以忽略误标记概率。模拟研究和真实数据分析都说明该有序误标记logistic回归方法在处理存在误标记的有序分类问题时效果很好。     

Validity Issues in Test Speededness

Speededness refers to the situation where the time limits on a standardized test do not allow substantial numbers of examinees to fully consider all test items. When tests are not intended to measure speed of responding, speededness introduces a severe threat to the validity of interpretations based on test scores. In this article, we describe test speededness, its potential threats to validity, and traditional and modern methods that can be used to assess the presence of speededness. We argue that more attention must be paid to this issue and that more research must be done to set appropriate time limits on power tests so that speed of responding does not interfere with the construct measured.     

论“加速度”式英语教学模式的理论与实践

在加速度存在的情况下,速度随着时间增加而加快。而在中国目前的英语教学中,每一个阶段和每一类语言知识讲授几乎都是采用同样的节奏和方式逐一进行,忽视了"加速度"的存在。针对英语课堂教学中的这些问题,构建一种全新"加速度"式的英语教学模式。在理论上,要明确"加速度"英语的本质和应用范围,要统一和明确教学目的,要建立"学而思,思而用"的教学方式,创造性地教与学。在教学实践中,典型例子法、数学模型法、逆向思维法、英汉对照法在一定程度上能促进学生创造性思维能力的发展。     

环境群体性事件的应急响应协同研究

引入环境群体性事件应急响应协同理论模型。以"厦门PX项目事件"为例,从权力、合法性与紧急性3个维度和7组利益相关者(包括单重属性的潜在型、随意型、苛求型,双重属性的支配型、依赖型、危险型,以及三重属性的决定型)的角度,对该理论进行实证分析,并从运作和政策层面对各利益相关者所处地位、行为模式进行探讨,以动态视角分析利益相关者的演变态势及其可能性。     

三轴加速度传感器系统在运动技术分析领域的研究与应用

为满足在运动训练过程中的人体三维空间技术特征研究的需要,开发一套三轴向加速度传感器系统.该系统由下位机和上位机两部分组成,其中下位机部分由加速度传感器、传感器拾取单元、数据处理单元、电源监测与保护单元和无线传输单元组成,上位机部分由数据采集和分析软件组成.该系统具有四通道同步采集功能,结合同步视频,可对运动员的肢体关节、比赛训练器械等技术组成要素进行运动学和动力学参数进行实时采集与分析.以体育训练中常用的杠铃深蹲训练为实验性应用领域,对速滑和举重两种项目的杠铃深蹲训练进行技术分析,通过对三轴加速度传感器采集数据的分析,找出不同项目间杠铃深蹲动作技术的特征与差异,为今后深入开展加速度传感器系统的开发与相关应用提供研究基础.     

Knowledge of bout duration influences pacing strategies during small-sided games

This investigation examines pacing during intermittent team sports. Sixteen junior Rugby League players participated in eight different small-sided offside touch games. All games were 24 min, but bout durations differed in continuous (1 × 24 min) or repeated (2 × 12, 3 × 8, 4 × 6, 6 × 4, 8 × 3, 12 × 2 or 24 × 1 min) formats. Repeat bouts were interspersed by 2 min of passive rest, and participants were informed of the bout duration immediately prior to the game. Heart rates, ratings of perceived exertion and data gathered from global positioning system devices were used to investigate the pacing strategies employed within each game. No significant (P > 0.05) between-game differences were observed in total distance; however, during the 1-min bouts, high-speed movement was significantly (P < 0.05) increased, during the first and second quarters of the 24 × 1-min game compared to all other formats (effect size range: 0.75 ± 0.61–1.38 ± 0.47). Furthermore, the rate of decline in high-speed movement over-time was greatest during the 24 × 1-min game with large differences observed between the first and third quarters (effect size: 0.90 ± 0.58). Greater moderate-speed (effect size range: 0.62 ± 0.63–1.56 ± 0.40) and less low-speed (effect size range: 0.69 ± 0.62–1.54 ± 0.40) distances were also observed during the 1-min bouts, yet heart rates were higher during the continuous 1 × 24-min game. Pacing strategies during intermittent activities are influenced by the number and duration of exercise bouts. Practitioners should consider within-game bout durations when prescribing game-based activities to improve aerobic capacity.     

地理信息系统专业遥感课程建设中的教学与科研互动关系探析

教学是立校之本,科研是强校之路,教学中有研究,在研究中教学。本文在分析地理信息系统专业遥感课程教学现状与人才培养矛盾的基础上,提出了新疆大学遥感专业教师应结合学校自身实际及教学内容,树立科研育人的理念,深化课程教学改革;通过教学、科研、学生能力培养以及成果产业化四互动,为提高遥感课程教学质量,培养实践创新型遥感人才的教学改革提供新思路,以使学生在多种育人方式和科研环境中得到全面发展。     

Modeling Growth in Electronic Learning Environments Using a Longitudinal Random Item Response Model

In educational environments, monitoring persons' progress over time may help teachers to evaluate the effectiveness of their teaching procedures. Electronic learning environments are increasingly being used as part of formal education and resulting datasets can be used to understand and to improve the environment. This study presents longitudinal models based on the item response theory (IRT) for measuring persons' ability within and between study sessions in data from web-based learning environments. Two empirical examples are used to illustrate the presented models. Results show that by incorporating time spent within- and between-study sessions into an IRT model; one is able to track changes in ability of a population of persons or for groups of persons at any time of the learning process.     

Dealing with Challenges of Energy and Climate Change:Policy-oriented Researches

<正>Rapid growth of total energy consumption and carbon emissions is a challenge to sustainable energy development In the first decade of the 21st century,along with the acceleration of industrialization and urbanization,especially the rapid development of heavy and chemical     

响应面法优化米曲霉HML366产β-葡萄糖苷酶发酵培养基

文章研究旨在优化前期筛选到的米曲霉HML366产β-葡萄糖苷酶的培养基条件。通过单因素实验和响应面设计对米曲霉HML366产β-葡萄糖苷酶的培养基条件进行了优化组合,确定最佳的发酵培养基配方为:甘蔗渣3.49%,豆饼粉0.375%,KH2PO4 0.255%。在此培养条件下得到β-葡萄糖苷酶酶活力达92.64 U/g,是未优化前酶活71.12 U/g的1.30倍。