多旋翼无人机微多普勒特性分析与特征提取     

马娇  董勇伟  李原  李凌霄  杨杰芳 《中国科学院大学学报》2019,36(2):235-243

针对多旋翼无人机目标的识别问题，提出一种基于伽柏（Gabor）变换的瞬时频率估计与快速傅里叶变换（FFT）相结合的微多普勒特征提取算法。首先建立多旋翼无人机旋翼回波模型，并通过仿真分析叶片数目、旋翼转速和初始相位等参数对微多普勒特征的影响，利用Gabor变换得到时频特征。在此基础上通过瞬时频率极大值法提取微多普勒频率，并对瞬时频率采用FFT提取旋翼数和转动频率，从而获得叶片长度估计值。实测数据验证了该算法较为准确地提取无人机的微多普勒参数。  相似文献   

Analysis of single comments left for bioRxiv preprints till September 2019     

Mario Mali ki  Joseph Costello  Juan Pablo Alperin  Lauren A. Maggio 《Biochemia medica : ?asopis Hrvatskoga dru?tva medicinskih biokemi?ara / HDMB》2021,31(2)

IntroductionWhile early commenting on studies is seen as one of the advantages of preprints, the type of such comments, and the people who post them, have not been systematically explored.Materials and methodsWe analysed comments posted between 21 May 2015 and 9 September 2019 for 1983 bioRxiv preprints that received only one comment on the bioRxiv website. The comment types were classified by three coders independently, with all differences resolved by consensus.ResultsOur analysis showed that 69% of comments were posted by non-authors (N = 1366), and 31% by the preprints’ authors themselves (N = 617). Twelve percent of non-author comments (N = 168) were full review reports traditionally found during journal review, while the rest most commonly contained praises (N = 577, 42%), suggestions (N = 399, 29%), or criticisms (N = 226, 17%). Authors’ comments most commonly contained publication status updates (N = 354, 57%), additional study information (N = 158, 26%), or solicited feedback for the preprints (N = 65, 11%).ConclusionsOur results indicate that comments posted for bioRxiv preprints may have potential benefits for both the public and the scholarly community. Further research is needed to measure the direct impact of these comments on comments made by journal peer reviewers, subsequent preprint versions or journal publications.  相似文献   

Value for learning during this time of transformation: the first-year students’ perspective     

Shalini Dukhan 《高等教育研究与发展》2020,39(1):39-52

ABSTRACT

Formal education was used by the apartheid government to prepare black South Africans for manual labour, thus there was little curricular focus on the development of higher-order cognitive skills. With the abolition of apartheid in 1994, the education system was re-valued and re-evaluated to provide wider access to quality education; the focus of education policies moved towards the development of self-regulation and higher-order cognitive skills for all learners. There is now a generation of learners who have experienced their schooling in the transformed education system, and it would be useful to understand, from their perspective, what they value in their development of learning within the higher education space. This study answers the question ‘Post-apartheid, what learning methods and resources do first-years perceive to be valuable to their learning when they enter university?’ Participants included 344 students taking a Biology course provided to medical science students at a South African university in 2018. Two questionnaires were administered towards the end of a six-week lecture period, responses were evaluated quantitatively and qualitatively. The first survey, comprised of Likert-style questions, was conducted to determine the students’ views on the mechanisms which they used to support their learning. The second questionnaire comprised open-ended questions and focused on the students’ perception of their learning experience in the course. The findings show that there was a significant (p?<?.001) percentage of first-years who thought that rote-learning would suffice for examination preparation at university, and preferred to engage with their peers and the textbook before they engaged with their lecturers when navigating challenging concepts. Schwartz's model of social values is used to show that more needs to be done for the development of higher-order thinking and self-regulation when students enter university, and to mitigate alienation between students and staff.  相似文献   

Associations between individual and collective efficacy beliefs and students' bystander behavior     

Björn Sjögren  Robert Thornberg  Linda Wänström  Gianluca Gini 《Psychology in the schools》2020,57(11):1710-1723

This study examined whether defending and passive bystanding during peer victimization episodes were associated with individual- and classroom-level efficacy to stop peer victimization. Self-report survey data were analyzed from 1,467 Swedish fourth-grade students (mean age = 10.55) from 100 classrooms in 63 schools. Multilevel analyses revealed that, when witnessing peer victimization, students more often defended victims if they were high in defender self-efficacy and if they belonged to classrooms high in collective efficacy. In contrast, students were more likely to remain passive if they were low in defender self-efficacy and if they belonged to classrooms low in collective efficacy. Taken together, our findings suggest that efficacy beliefs both at the individual and at the classroom level contribute to explaining variability in students' bystander behaviors, which has potential implications for prevention and intervention work.  相似文献   

Assessing intellectual potential in Tanzanian children in poor areas of Dar es Salaam     

Steve Humble  Ian Schagen 《Assessment in Education: Principles, Policy & Practice》2018,25(4):399-414

The research set out in this paper attempts to identify whether one of three conventional IQ tests is more capable of identifying intellectual potential amongst poor children in Dar es Salaam. To this end 1857 children from 17 government schools in poor districts of Dar es Salaam were asked to complete a questionnaire and undertake a range of tests. The study included teacher, peer and self-nomination. It has been noted that static testing may not fully elicit the abilities of African children. It has been suggested that dynamic testing might provide a more fair and equitable means of assessment. Therefore 101 students took part in a control and intervention group in order to investigate. The findings show a significant correlation between IQ test scores and other test outcomes. Those with larger families and older children perform less well on IQ tests. Peer ability and self-confidence positively influence test scores.  相似文献   

Leading Developmental Peer Observation of Teaching in Higher Education: Perspectives from Australia and England     

Dallas Wingrove  Linda Hammersley-Fletcher  Angela Clarke  Andrea Chester 《British Journal of Educational Studies》2018,66(3):365-381

Whilst peer observation of teaching is well established as a practice that can enhance teaching quality, the challenge to fully embed this practice in universities remains unresolved. This article analyses the perspectives of 18 university leaders (nine Australian and nine English) drawn from a range of school-based leaders to senior leaders of learning and teaching. Our study indicates that some of the challenges associated with leading such schemes can be mitigated through approaches to educational leadership that enact a respectful and collegiate ethos. This we suggest can support developmental academic engagement in peer observation for positive and lasting change.  相似文献   

基于二模复杂网络的隐性知识发现方法研究——以潜在药物靶点挖掘为例     

李东巧  陈芳  韩涛  杨艳萍  王学昭  王燕鹏  Cynthia Liu  Yingzhu Li 《图书情报工作》2020,64(21):120-129

[目的/意义] 通过构建二模复杂网络模型，揭示隐藏在海量文献中的隐性知识。[方法/过程] 通过NetworkX复杂网络工具包，依据任意两个节点的共现关系构建二模复杂网络模型；对网络模型中节点的共现关系进行加权，计算网络的拓扑信息并进行AP聚类，提取节点间的直接关系；采用AUC方法对AA、JC、加权改进的wAA和wJC等4种链路预测算法进行评价，遴选出最合适的预测算法，并对复杂网络的隐性关系进行预测分析。[结果/结论] 以潜在药物靶点挖掘为例进行的实证研究结果表明，wAA链路预测算法为最优的链路预测算法；二模复杂网络模型、指标和方法体系在美国化学文摘社数据库中的药物靶点挖掘中具有一定的有效性。下一步计划在其他数据库中或其他研究领域中进行尝试，以进一步验证该模型的通用性和有效性。  相似文献   

优秀双向飞碟运动员3号 靶位击发节奏与脱靶关系研究     

耿正洋 《河北体育学院学报》2020,34(4):71-75

双向飞碟射击项目中3号靶位是8个靶位中射击命中难度最大的靶位，是制约运动员整体命中率的关键所在。将双向飞碟双靶分为1靶击发、随靶、2靶击发3个阶段，对3名国内优秀运动员击发节奏特征进行分析。发现：①1靶击发阶段的节奏直接影响2靶中靶情况，1靶击发用时越长，2靶质量越差，想要提高2靶的命中率必须要提高1靶的动作质量。②随靶阶段的人枪结合能力会影响2靶命中率。③优秀运动员2靶击发阶段的时间节奏一致性较强，动作自动化程度较高。④整体击发节奏慢更易造成2靶脱靶。提出，运动员要提高打好1靶的能力，在保证1靶质量的前提下加强快打技术训练，同时提高随靶阶段人枪结合能力，加强对技术的监控和分析，辅助运动训练，科学提高成绩。  相似文献   

科技期刊实施开放式同行评议策略研究     

彭琳  杜杏叶 《中国科技期刊研究》2018,29(11):1114-1121

【目的】 调研国内外科技期刊实施开放式同行评议(Open Peer Review，OPR)的策略，并对其进行比较分析，以期为OPR相关理论和实践研究提供参考。【方法】 通过在30种科技期刊官方网站收集数据，总结OPR期刊的特点，比较各期刊在采取审稿模式、公开审稿人身份、公开审稿意见和给审稿人认可等方面采取的不同策略。【结果】 所调研期刊中绝大多数是出版集团拥有的开放获取期刊，其中50%是生物医学类期刊。在所调查的3种OPR模式中，70%期刊采取模式2，即公开评审结果模式；23%采用模式1，即审稿中增加公众评议环节；7%采用非主流模式3，即通过出版“同行评议书”的方式公开稿件评审过程。即使采用同一种OPR模式的期刊，其具体做法也不尽相同。71%的期刊采取自愿署名或匿名审稿政策，只有29%的期刊要求审稿人实名审稿。小部分期刊采取给评审报告添加DOI方式激励审稿人审稿。【结论】 当前国内外科技期刊对OPR的研究和实践还处在初级阶段，实施OPR的期刊总体数量偏少，今后还需要各期刊根据自己的特点探索适合自己实施OPR的策略。  相似文献   

The Spectrum of Learning and Teaching: The Impact of a Fourth-Year Anatomy Course on Medical Student Knowledge and Confidence     

Rebecca S. Lufler  Michelle D. Lazarus  Joshua J. Stefanik 《Anatomical sciences education》2020,13(1):19-29

There is growing demand from accrediting agencies for improved basic science integration into fourth-year medical curricula and inculcation of medical students with teaching skills. The objective of this study was to determine the effectiveness of a fourth-year medical school elective course focused on teaching gross anatomy on anatomical knowledge and teaching confidence. Fourth-year medical student “teacher” participants' gross anatomy knowledge was assessed before and after the course. Students rated their overall perceived anatomy knowledge and teaching skills on a scale from 0 (worst) to 10 (best), and responded to specific knowledge and teaching confidence items using a similar scale. First-year students were surveyed to evaluate the effectiveness of the fourth-year student teaching on their learning. Thirty-two students completed the course. The mean anatomy knowledge pretest score and posttest scores were 43.2 (±22.1) and 74.1 (±18.4), respectively (P < 0.001). The mean perceived anatomy knowledge ratings before and after the course were 6.19 (±1.84) and 7.84 (±1.30), respectively (P < 0.0001) and mean perceived teaching skills ratings before and after the course were 7.94 (±1.24) and 8.53 (±0.95), respectively (P = 0.002). Student feedback highlighted five themes which impacted fourth-year teaching assistant effectiveness, including social/cognitive congruence and improved access to learning opportunities. Together these results suggest that integrating fourth-year medical students in anatomy teaching increases their anatomical knowledge and improves measures of perceived confidence in both teaching and anatomy knowledge. The thematic analysis revealed that this initiative has positive benefits for first-year students.  相似文献