1,721,925 research outputs found
QI,CHENG,ZHUAN,HE:Four Components of the On-line Education
Get PDF网络教育产生的时间不长 ,但已促使全世界都在进行大规模的研究和尝试 ,在我国也不例外。网络教育是从教育教学手段、教学内容、模式到教育理念都大大有别于以往传统教育的一种新型教育形式 ,是一种蕴涵着众多“革命性”因素的教育形式。本文试图借用“起承转合”四个字来对这些复杂的因素做出归并和梳理 ,从而有助于今后对网络教育更为科学和全面的研究The on line education is a new educational form Many related researches and practices have been made in recent years It differs greatly from the traditional education in means, contents, models and ideas This article tries to use "Qi, Cheng, Zhuan, He" to combine all the aspects related to on-line education and build a frame for further stud
Fully Dynamic Four-Vertex Subgraph Counting
Get PDFThis paper presents a comprehensive study of algorithms for maintaining the number of all connected four-vertex subgraphs in a dynamic graph. Specifically, our algorithms maintain the number of paths of length three in deterministic amortized O(m^{1/2}) update time, and any other connected four-vertex subgraph which is not a clique in deterministic amortized update time O(m^{2/3}). Queries can be answered in constant time. We also study the query times for subgraphs containing an arbitrary edge that is supplied only with the query as well as the case where only subgraphs containing a vertex s that is fixed beforehand are considered. For length-3 paths, paws, 4-cycles, and diamonds our bounds match or are not far from (conditional) lower bounds: Based on the OMv conjecture we show that any dynamic algorithm that detects the existence of paws, diamonds, or 4-cycles or that counts length-3 paths takes update time Ω(m^{1/2-δ}).
Additionally, for 4-cliques and all connected induced subgraphs, we show a lower bound of Ω(m^{1-δ}) for any small constant δ > 0 for the amortized update time, assuming the static combinatorial 4-clique conjecture holds. This shows that the O(m) algorithm by Eppstein et al. [David Eppstein et al., 2012] for these subgraphs cannot be improved by a polynomial factor
Tipula (Vestiplex) avicularia Edwards 1928
No full textTipula (Vestiplex) avicularia group Tipula (Vestiplex) avicularia Edwards, 1928Published as part of Yang, Qi-cheng, Pan, Zhao-hui, Liu, Xiao-yan & Yang, Ding, 2021, Six new species of Tipula (Vestiplex) Bezzi (Diptera, Tipulidae) from Tibet, pp. 152-192 in European Journal of Taxonomy 764 (1) on page 184, DOI: 10.5852/ejt.2021.764.1477, http://zenodo.org/record/551446
Tipula (Vestiplex) eurydice Alexander 1961
No full textTipula (Vestiplex) eurydice group Tipula (Vestiplex) eurydice Alexander, 1961Published as part of Yang, Qi-cheng, Pan, Zhao-hui, Liu, Xiao-yan & Yang, Ding, 2021, Six new species of Tipula (Vestiplex) Bezzi (Diptera, Tipulidae) from Tibet, pp. 152-192 in European Journal of Taxonomy 764 (1) on page 184, DOI: 10.5852/ejt.2021.764.1477, http://zenodo.org/record/551446
Tipula (Vestiplex) coquillettiana Alexander 1924
No full textTipula (Vestiplex) coquillettiana group Tipula (Vestiplex) scandens Edwards, 1928Published as part of Yang, Qi-cheng, Pan, Zhao-hui, Liu, Xiao-yan & Yang, Ding, 2021, Six new species of Tipula (Vestiplex) Bezzi (Diptera, Tipulidae) from Tibet, pp. 152-192 in European Journal of Taxonomy 764 (1) on page 184, DOI: 10.5852/ejt.2021.764.1477, http://zenodo.org/record/551446
Tipula (Vestiplex) scripta Meigen 1830
No full textTipula (Vestiplex) scripta group Tipula (Vestiplex) subscripta Edwards, 1928Published as part of Yang, Qi-cheng, Pan, Zhao-hui, Liu, Xiao-yan & Yang, Ding, 2021, Six new species of Tipula (Vestiplex) Bezzi (Diptera, Tipulidae) from Tibet, pp. 152-192 in European Journal of Taxonomy 764 (1) on page 184, DOI: 10.5852/ejt.2021.764.1477, http://zenodo.org/record/551446
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Figs 10–12 in Six new species of Tipula (Vestiplex) Bezzi (Diptera, Tipulidae) from Tibet
No full textFigs 10–12. Tipula (Vestiplex) uncinella sp. nov., paratypes, ♂♂ (CAU). 10. Habitus, lateral view. 11. Wing. 12. Habitus, dorsal view. Abbreviations: see Material and methods. Scale bars = 1.0 mm.Published as part of Yang, Qi-cheng, Pan, Zhao-hui, Liu, Xiao-yan & Yang, Ding, 2021, Six new species of Tipula (Vestiplex) Bezzi (Diptera, Tipulidae) from Tibet, pp. 152-192 in European Journal of Taxonomy 764 (1) on page 160, DOI: 10.5852/ejt.2021.764.1477, http://zenodo.org/record/551446
Figs 84–86. 84 in Six new species of Tipula (Vestiplex) Bezzi (Diptera, Tipulidae) from Tibet
No full textFigs 84–86. 84. Tipula (Vestiplex) bucera sp. nov., mating. 85. Habitat of 80K, Muotuo, Tibet, China. 86. Habitat of Yigong, Bomi, Tibet, China.Published as part of Yang, Qi-cheng, Pan, Zhao-hui, Liu, Xiao-yan & Yang, Ding, 2021, Six new species of Tipula (Vestiplex) Bezzi (Diptera, Tipulidae) from Tibet, pp. 152-192 in European Journal of Taxonomy 764 (1) on page 189, DOI: 10.5852/ejt.2021.764.1477, http://zenodo.org/record/551446
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