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   

微助教在教学中的应用     

马玉花  彭荣贞  谷晓凤 《教育教学论坛》2020,(5):250-251

随着信息技术的快速发展和教育理念的不断更新,符合信息化教学时代背景的学习型微信公众平台——微助教应运而生,成为教育界的新星,从而真正实现个性化教学,为教学改革注入新的活力。文章将对微助教的功能特色以及利用其辅助大班课堂教学的优势进行简单的总结概述,并对其做出简要的分析,提出一些理解与看法。  相似文献   

Methods for assessing higher education research team collaboration: comparing research outputs and participant perceptions across four collaborative research teams     

Nick Kelly  Joanne Doyle  Marisa Parker 《高等教育研究与发展》2020,39(2):215-229

ABSTRACT

This article suggests that situations in which multiple research teams are convened under similar conditions present an opportunity to discover factors that lead to productive collaboration. It argues that social network analysis of research team outputs becomes more valuable when paired with data about research participant perceptions; and that any variables used as indicators of collaboration need to be calibrated using datasets from multiple studies with cross-team comparisons. The article provides an example of the kind of methodology needed to achieve this, describing a study with data from four research teams based at an Australian university campus, reporting their research performance over four years under conditions in which many variables were controlled and with results augmented by a survey of participant perceptions. Findings from the study indicate that there were exceptions to hypothesized associations between participant perceptions of collaboration and specific social network analysis measures over co-authorship data. The article suggests that, given the methodological challenges of studying research teams in the field, multiple datasets combining findings such as those in the present study are a path towards the development of indicators of productive higher education research collaboration.  相似文献   

我国警察体育研究的基本现状研究* ——基于Bibexcel的文献计量与可视化分析     

林〓通  姬艳涛  王〓犇 《广州体育学院学报》2019,(5):59-62

首先对中国知网数据库中收录的以警察体育为主题的文献时序分布进行梳理，通过论文发表时间与数量的变量关系对比，分析揭示该研究领域的历史脉络、发展速度以及演变规律。随后利用信息可视化软件Bibexcel绘制出警察体育研究领域的核心作者、研究机构、高被引文献的知识图谱,阐释该领域的研究结构、力量分布以及合作平台建设等情况。最后运用词频分析、共词聚类和可视化法生成关键词共现网络图谱，挖掘、提炼文献数据背后的规律与逻辑，捕捉警察体育研究领域中的研究热点和前沿动态，并在此基础上深入探讨警察体育未来研究的基本趋势和发展方向。  相似文献   

Writer identification approach based on bag of words with OBI features     

Amal Durou  Ibrahim Aref  Somaya Al-Maadeed  Ahmed Bouridane  Elhadj Benkhelifa 《Information processing & management》2019,56(2):354-366

Handwriter identification aims to simplify the task of forensic experts by providing them with semi-automated tools in order to enable them to narrow down the search to determine the final identification of an unknown handwritten sample. An identification algorithm aims to produce a list of predicted writers of the unknown handwritten sample ranked in terms of confidence measure metrics for use by the forensic expert will make the final decision.Most existing handwriter identification systems use either statistical or model-based approaches. To further improve the performances this paper proposes to deploy a combination of both approaches using Oriented Basic Image features and the concept of graphemes codebook. To reduce the resulting high dimensionality of the feature vector a Kernel Principal Component Analysis has been used. To gauge the effectiveness of the proposed method a performance analysis, using IAM dataset for English handwriting and ICFHR 2012 dataset for Arabic handwriting, has been carried out. The results obtained achieved an accuracy of 96% thus demonstrating its superiority when compared against similar techniques.  相似文献   

Knowledge-guided multi-granularity GCN for ABSA     

《Information processing & management》2023,60(2):103223

Aspect-based sentiment analysis aims to determine sentiment polarities toward specific aspect terms within the same sentence or document. Most recent studies adopted attention-based neural network models to implicitly connect aspect terms with context words. However, these studies were limited by insufficient interaction between aspect terms and opinion words, leading to poor performance on robustness test sets. In addition, we have found that robustness test sets create new sentences that interfere with the original information of a sentence, which often makes the text too long and leads to the problem of long-distance dependence. Simultaneously, these new sentences produce more non-target aspect terms, misleading the model because of the lack of relevant knowledge guidance. This study proposes a knowledge guided multi-granularity graph convolutional neural network (KMGCN) to solve these problems. The multi-granularity attention mechanism is designed to enhance the interaction between aspect terms and opinion words. To address the long-distance dependence, KMGCN uses a graph convolutional network that relies on a semantic map based on fine-tuning pre-trained models. In particular, KMGCN uses a mask mechanism guided by conceptual knowledge to encounter more aspect terms (including target and non-target aspect terms). Experiments are conducted on 12 SemEval-2014 variant benchmarking datasets, and the results demonstrated the effectiveness of the proposed framework.  相似文献   

Factors influencing the career interest of SENCOs in English schools     

Graeme Dobson  Graeme Douglas 《British Educational Research Journal》2020,46(6):1256-1278

A named professional with responsibility for overseeing and coordinating the educational inclusion of pupils with special educational needs and disabilities has become an important school role in many countries. In England, the SENCO (special educational needs coordinator) became a mandatory role in 1994, and associated mandatory training was introduced in 2009. A questionnaire survey of 618 in-training and actual SENCOs revealed that their motivating interest in becoming a SENCO varied. An exploratory factor analysis of 32 items covering different interests in the role yielded four interest factors in becoming a SENCO: outward-facing factors (‘inclusion’ and ‘high-quality provision’) and inward-facing factors (‘educational and professional development’ and ‘leadership voice and status’). The outward-facing factors were viewed as more important to respondents than the inward-facing factors. Interest factors did not interact with organisational variables, including age group taught and school quality. Nevertheless, younger SENCOs and those engaged in training were more motivated by educational and professional development. SENCOs holding school leadership contracts were more motivated in developing leadership voice and status compared with their classroom teacher peers. Moreover, there was a significant overall difference with women reporting a higher interest than men across all factors.  相似文献   

Practices more likely to occur in kindergarten mathematics teachers’ instruction when English learners are present     

《Learning and Instruction》2020

Considering the rising proportion of English learners (ELs) in general education, little is known about how this change in classroom composition relates to the frequency of instructional activities and skills. This study uses a multimodal perspective on learning mathematics in a multilingual context, which recognizes the diverse modes of communication that students draw on in mathematics classrooms. We examined national data using quantitative analyses and investigated the mathematics practices that were more likely to occur in kindergarten classrooms that did and did not have ELs. We found teachers reported greater frequency of manipulatives and count/calendar activities in mathematics instruction when there were EL students in the classroom. Teachers in classrooms with ELs also reported a greater frequency of mathematics content that involved teaching shapes and practical skills. The findings indicate that teachers tended towards a supportive multimodal approach to instruction when ELs were present.  相似文献   

基于Cite Space的国内身体功能训练研究计量学分析     

蒋晓帆 《体育科技文献通报》2020,(1):155-157

运用中国知网(CNKI)检索库进行检索,共查找到期刊文献115篇,其中国内期刊65篇,硕士论文31篇。通过Cite Space和中国知网(CNKI)文献分析功能,对国内身体功能训练研究进行计量学分析。研究的基本特征表现为:研究机构多,文献期刊发表数量较少,核心期刊占比较少,论文质量与数量之间存在差异。研究热点以身体功能训练为主,并突显了“功能训练”“训练”和“体育工作者”等关键词,作者合作比较少,仅形成数个微小的作者合作网络。  相似文献   

Does modality matter? A latent profile and transition analysis of sedentary behaviours among school-aged youth: The UP&DOWN study     

David Sánchez-Oliva  Rebecca M. Leech  Alberto Grao-Cruces  Irene Esteban-Cornejo  Carmen Padilla-Moledo  Oscar L. Veiga 《Journal of sports sciences》2020,38(9):1062-1069

ABSTRACT

The aims of this study were to identify profiles of sedentary behaviour (SB) patterns, based on leisure-time self-reported SB modalities (screen, educative, social, and relaxing) and to evaluate changes in these profiles over 2 years among Spanish youth aged 8–18 years. Latent profile analysis (LPA), a data-driven analytic approach, was used to identify groups of boys and girls (n = 1553; 48% girls; mean±SD age: 12.56 ± 2.49 y) with distinct SB profiles using the SB modalities (time/d) as input variables. Latent transition analysis, an extension of LPA that uses longitudinal data, was used to analyse 2-year changes in these profiles. At baseline, four and three SB profiles were found among boys (labelled: screen, educative, social, and relaxing) and girls (labelled: screen/social, educative, and relaxing), respectively. Overall, more girls (range: 48%-67%) had the same profile over time, than boys (40%-52%). Participants with a screen or relaxing SB profile at baseline were more likely to have an educative profile after 2 years. Youth with a social and an educative SB profile at baseline were more likely to transition to profiles characterized by higher screen and social SB, respectively. Using a novel and person-centered approach, this study identified gender-specific SB profiles that were moderately stable over time.  相似文献