一类正则化方法的收敛速率     

尹秀玲 《喀什师范学院学报》2008,29(6):6-9

考虑了解不适定问题的迭代Tikhonov正则化方法的渐近收敛速率．采用对数度量作为广义解x^4的分类标准．对于数据没有或有误差的两种情形,都得到关于渐进收敛速率的相当精细的结论．  相似文献   

The alignment of written peer feedback with draft problems and its impact on revision in peer assessment     

Ying Gao  Qiuying Yu 《Assessment & Evaluation in Higher Education》2019,44(2):294-308

Despite the wide use of peer assessment, questions about the helpfulness of peer feedback are frequently raised. In particular, it is unknown whether, how and to what extent peer feedback can help solve problems in initial texts in complex writing tasks. We investigated this research gap by focusing on the case of writing literature reviews in an academic writing course. The dataset includes two drafts from 21 students, sampled to represent a wide range of document qualities, and 84 anonymous peer reviews, involving 1,289 idea units. Our study revealed that: (1) at both substance and high prose levels, drafts of all quality levels demonstrated more common problems on advanced writing issues (e.g. counter-argument); (2) peer feedback was driven by difficulty of the problem rather than overall draft quality, peer comments were not well aligned with the relative frequency of problems, more comments were given to less difficult problems; (3) peer feedback had a moderate impact on revision, and importantly, receiving multiple comments on the same issue led to more repairs and improvement of draft quality, but consistent with the comments received, authors tended to fix basic problems more often. Implications for practice and research are drawn from these findings.  相似文献   

理财产品能否“理财”     

方海英 《天津职业院校联合学报》2011,13(12):87-90

中国各商业银行理财产品实质上是一种金融投资产品,这些理财产品对于防范通胀,实现居民投资者保值增值的理财目标具有一定价值。  相似文献   

Using micro-sensor data to quantify macro kinematics of classical cross-country skiing during on-snow training     

Finn Marsland  Colin Mackintosh  Judith Anson  Keith Lyons  Gordon Waddington  Dale W. Chapman 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(4):435-447

Abstract

Micro-sensors were used to quantify macro kinematics of classical cross-country skiing techniques and measure cycle rates and cycle lengths during on-snow training. Data were collected from seven national level participants skiing at two submaximal intensities while wearing a micro-sensor unit (MinimaxX^?). Algorithms were developed identifying double poling (DP), diagonal striding (DS), kick-double poling (KDP), tucking (Tuck), and turning (Turn). Technique duration (T-time), cycle rates, and cycle counts were compared to video-derived data to assess system accuracy. There was good reliability between micro-sensor and video calculated cycle rates for DP, DS, and KDP, with small mean differences (Mdiff% = ?0.2 ± 3.2, ?1.5 ± 2.2 and ?1.4 ± 6.2) and trivial to small effect sizes (ES = 0.20, 0.30 and 0.13). Very strong correlations were observed for DP, DS, and KDP for T-time (r = 0.87–0.99) and cycle count (r = 0.87–0.99), while mean values were under-reported by the micro-sensor. Incorrect Turn detection was a major factor in technique cycle misclassification. Data presented highlight the potential of automated ski technique classification in cross-country skiing research. With further refinement, this approach will allow many applied questions associated with pacing, fatigue, technique selection and power output during training and competition to be answered.  相似文献   

Reading and Related Skills in the Early School Years: Are boys really more likely to struggle?     

Lisa Limbrick  Kevin Wheldall  Alison Madelaine 《International Journal of Disability, Development & Education》2012,59(4):341-358

This study examined whether boys and girls in the early school years differed in reading and related skills, and their rates of progress. Gender ratios were calculated to ascertain whether there were more boys than girls who struggle with different facets of reading, and whether the variability of boys’ scores resulted in more boys being identified as poor readers, as evidenced by previous studies. A sample of 335 students in Years 1 and 2 were administered six reading and related assessments. Boys and girls did not significantly differ on any of the measures, and differences in gains were negligible. Boys did not consistently demonstrate significantly greater variability in scores (with the exception of single-word reading and spelling in Year 1 only). These differences, however, did not affect gender ratios for poor performance. Gender ratios were relatively low across measures, but increased with years of schooling. Implications of the results are discussed.  相似文献   

Lecturing and other face-to-face teaching – too much or too little? An assessment based on student feedback and fail rates     

Matthew R.E. Symonds 《高等教育研究与发展》2014,33(6):1221-1231

Institutes of higher learning are tending to reduce the amount of face-to-face teaching that they offer, and particularly through the traditional pedagogical method of lecturing. There is ongoing debate about the educational value of lectures as a teaching approach, in terms of both whether they facilitate understanding of subject material and whether they augment the student educational experience. In this study, student evaluation of teaching scores plus academic outcome (percentage of students who fail) was assessed for 236 course units offered by a science faculty at an Australian university over the course of one year. These measures were related to the degree to which lectures and other face-to-face teaching were used in these units, controlling for factors such as class size, school and year level. An information-theoretic model selection approach was employed to identify the best models and predictors of student assessments and fail rates. All the top models of student feedback included a measure reflecting amount of face-to-face teaching, with the evaluation of quality of teaching being higher in units with higher proportions of lectures. However, these models explained only 12–20% of the variation in student evaluation scores, suggesting that many other factors come into play. By contrast, units with fewer lectures have lower failure rates. These results suggest that moving away from lectures and face-to-face teaching may not harm, and indeed may improve the number of students who pass the subject, but that this may be incurred at the expense of greater dissatisfaction in students' learning experience.  相似文献   

不同渗透压对猪精子膜功能完整性测定的影响     

庞训胜  汪孟全  陈凤山  张拯  李冠军  孙红生 《安徽科技学院学报》2002,16(4):16-17

分别以葡萄糖和蔗糖构成的低渗透压系列处理猪精液,研究渗透和非渗透性物质对精子膜功能完整性测定值的影响.结果表明当低渗压值为12.8mOsm时精子膨胀率最高,渗透和非渗透性不是影响客观评定猪精子膜功能完整性的主要因素.  相似文献   

欧洲人力资本收益率:文献综述   总被引：2，自引：0，他引：2  

郑洁  武向荣  赖德胜 《比较教育研究》2003,24(12):25-30

本文对欧洲十五个国家近期人力资本收益率的研究方法和成果进行了评述,包括数据采编、模型构建、变量定义与控制、估计工具选择以及对人力资本收益率的定性评价等,希望能对我国人力资本收益率研究有重要的借鉴和参考价值。  相似文献   

实验教学大型仪器使用率模式探索     

姚美银 《教育教学论坛》2019,(2):277-278

高校大型仪器平台作为我国分析测试领域的重要组成部分,承担了大量的科研教学测试服务工作。随着高校大型仪器规模的增加,部分大型仪器使用率低下和资源浪费的现象较为严重。作为国内高校大型仪器平台,实验教学是除了测试服务与科学研究之外最为重要的本职工作。鉴于此,本课题探讨了以大型仪器实验为支撑,开展实验技能强化教学,为提高高校大型仪器共享使用率提供新的思路和途径。  相似文献   

A Longitudinal Study of the Talent Search Program     

Ernest?W.?BrewerEmail author  Jama?McMahan?Landers 《Journal of Career Development》2005,31(3):195-208

This longitudinal study examined the impact of participation in the federally funded Talent Search program at The University of Tennessee, Knoxville. The Talent Search program provides career exploration and counseling services to low-income students with the potential to be first-generation college graduates. Postsecondary education enrollment rates of 758 Talent Search participants were compared with enrollment rates of a control group of 450 individuals who were eligible for Talent Search services but did not participate. Chi-square analysis revealed that Talent Search participants were significantly more likely to enroll in postsecondary education than were members of the control group (p < .001). These results have implications for career development services provided to low-income, potential first-generation college graduates.  相似文献