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用优势树全高和胸径的关系评价红松林的立地质量 被引量:24
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作者 马建路 宣立峰 刘德君 《东北林业大学学报》 CAS CSCD 北大核心 1995年第2期20-27,共8页
柞树红松林、鱼鳞云杉红松林、云冷杉红松林、椴树红松林、枫桦红松林和春榆、水曲柳红松林是小兴安岭南坡红松天然林中常见的6个立地类型。不同立地类型红松优势树高、胸径和年龄三者之间关系分析的结果表明年龄在决定红松优势树高上... 柞树红松林、鱼鳞云杉红松林、云冷杉红松林、椴树红松林、枫桦红松林和春榆、水曲柳红松林是小兴安岭南坡红松天然林中常见的6个立地类型。不同立地类型红松优势树高、胸径和年龄三者之间关系分析的结果表明年龄在决定红松优势树高上的意义不大.而优势树高与胸径的相关性密切.符合Richards方程。采用优势树在一定胸径(40cm)时的高度值表达立地指数。红松林6个立3也的立地质量差异明显,平均立地指数相差最大可达7m。并讨论了这种新评价方法的理论基础、精度及其在天然复层异龄混交林经营实践中的意义。 展开更多
关键词 优势树 优势树胸径 立地质量评价 红松 天然林
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郑州北龙湖湿地公园花境植物应用研究 被引量:1
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作者 雷天 王霄 +2 位作者 尤其 聂雅心 王鹏飞 《林业调查规划》 2023年第5期104-108,共5页
随着园林绿化的快速发展,花境园在园林中的应用越来越广泛。以北龙湖湿地公园54个花境园为研究对象,对该区域花境植物种类、使用频次、应用情况以及花境色彩等方面进行研究。研究表明,花镜植物共80科、213属、320种,优势科为菊科、禾本... 随着园林绿化的快速发展,花境园在园林中的应用越来越广泛。以北龙湖湿地公园54个花境园为研究对象,对该区域花境植物种类、使用频次、应用情况以及花境色彩等方面进行研究。研究表明,花镜植物共80科、213属、320种,优势科为菊科、禾本科、唇形科、蔷薇科、百合科、马鞭草科、玄参科;花镜园中使用植物主要以多年生草本为主,其次是灌木,使用频次较高的植物为亮晶女贞和松果菊;花镜整体以紫色系植物居多,其次是黄色系、红色系植物。结合北龙湖花境植物的分析研究,对花境植物优化配置以及花境材料的选择提出相关参考。 展开更多
关键词 花境 花境植物 优势树 使用频次 植物色彩 郑州市
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基于VQ和GMM的实时声纹识别研究 被引量:3
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作者 鲁晓倩 关胜晓 《计算机系统应用》 2014年第9期6-12,共7页
目前声纹识别系统已经实现较高的识别精度,但是随着目标说话人个数的增加,一般系统很难满足实时性的要求,由此提出一种双层识别模型.在第一层识别模型中,采用基于VQ-VPT(Vector Quantization-Vantage Point Tree)模型进行快速匹配,挑选... 目前声纹识别系统已经实现较高的识别精度,但是随着目标说话人个数的增加,一般系统很难满足实时性的要求,由此提出一种双层识别模型.在第一层识别模型中,采用基于VQ-VPT(Vector Quantization-Vantage Point Tree)模型进行快速匹配,挑选出与测试者声纹特征最相近的K个目标说话人声纹模型.在第二层识别模型中,采用GMM-UBM(Gaussian Mixture Model-Universal Background Model)模型,精确匹配上层模型得到的K个目标说话人声纹模型,并做出最终的判决.实验验证,双层识别模型在确保高识别精度的前提下,大幅度的提高了系统的识别速度. 展开更多
关键词 声纹识别 矢量量化 优势节点 高斯混合模型 通用背景模型
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Ecological Species Groups and Interspecific Association of Dominant Tree Species in Daiyun Mountain National Nature Reserve 被引量:40
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作者 SU Song-jin LIU Jin-fu +3 位作者 HE Zhong-sheng ZHENG Shi-qun HONG Wei XU Dao-wei 《Journal of Mountain Science》 SCIE CSCD 2015年第3期637-646,共10页
Abstract: Research on the ecological species groups and interspecific association of plant species are helpful to discover species coexistence processes and mechanisms, and to more fully understand plant community st... Abstract: Research on the ecological species groups and interspecific association of plant species are helpful to discover species coexistence processes and mechanisms, and to more fully understand plant community structure, function, and its taxonomy. However, little is known about the ecological species groups (ESG) and the interspecific association of dominant species in Daiyun Mountain National Nature Reserve of Fujian Province, China. Therefore, the main goal of this paper is to explore the ESG using maximal tree, and to analyze interspecific associations of 32 dominant species selected from lo2 sample plots using the chi-square test. The results show that: (1) 32 dominant species have a significant overall positive interspecific association, which indicates that the natural forest in Daiyun Mountain National Nature Reserve is stable, (a) The species pairs with weak associations, non-associations and positive associations account for lo.88%, 29.64% and 59.48% of the total 496 species pairs respectively, which suggests that the population distributions of the dominant species investigated are relatively independent, (3) The following species pairs may be useful for practical application, 〈Pinus taiwanensis, Rhododendron farrerae〉, 〈Castanopsis carlesii, Altingia chinensis〉, 〈C. carlesii, Castanopsis fargesii〉, 〈Castanopsis eyrei, C. fargesii〉, 〈P. taiwanensis, Fagus lucida〉 , 〈Machilus thunbergii, Castanopsis nigrescens〉, and (4) The results of clustering analysis based on the maximal tree method indicates that the 32 dominant species can be divided into 3 ESGs when A at o.6o, that is ESG I {Pinus massoniana, Cunning hamia lanceolata}, ESG II {P. taiwanensis, R. farrerae, Enkianthus quinqueflorus}, ESG III {C. carlesii, A. chinensis, C. eyrei, Castanopsis fabri, C. fargesii, Schima superba, Machilus thunbergii, Rhododendron latoueheae}. The results may be used for the selection of afforestation tree species in South China Forest Areas and guide the natural management of plantations. 展开更多
关键词 Ecological Species Groups InterspecificAssociation Daiyun Mountain National NatureReserve Maximal Tree
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Distribution Patterns and Associations of Dominant Tree Species in a Mixed Coniferous-Broadleaf Forest in the Changbai Mountains 被引量:9
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作者 ZHANG Meng-tao KANG Xin-gang +1 位作者 MENG Jing-hui ZHANG Li-xin 《Journal of Mountain Science》 SCIE CSCD 2015年第3期659-670,共12页
In 2012 a plot was established with 1-ha area in a mixed coniferous-broadleaf forest in the Changbai Mountains, northeastern China for examining local forest processes, structure and succession. A method of O-ring sta... In 2012 a plot was established with 1-ha area in a mixed coniferous-broadleaf forest in the Changbai Mountains, northeastern China for examining local forest processes, structure and succession. A method of O-ring statistics (pair- correlation function) was applied to analyze the spatial patterns and associations of the dominant species within different vertical layers. After the evaluation by their importance values, six tree species (or group) (i.e. Abies nephrolepis, Picea jezoensis, Pinus koraiensis, Tilia amurensis, and species group of Betula ssp. and species group of Acer ssp.) were determined as dominant trees species. It was found that some of these species exhibited closely clustered distributions at fine distances. As spatial distance increased, a random or even regular distribution gradually appeared with the exception of the upper layers of A. nephrolepis and P. koraiensis, and the lower layers of P. jezoensis, P. koraiensis and Betula ssp., which were substantially randomly distributed. Intra- and inter-species spatial associations varied in accordance with species, tree height and reciprocal distances. Positive associations were observed between the lower and upper height classes of trees of the same species (except for that of P. jezoensis) at fine distances. This may be owing to limited seed dispersal and geological heterogeneity. The aggregation intensity declines with increasing distances and this consistent with the predictions of self-thinning. Some coniferous trees (e.g. Pinus koraiensis) in the lower height class were positively associated with T. amurensis and group of Betula ssp. of the upper height class at some distances, suggesting that saplings of coniferous trees occupy a broader niche and can grow well under the canopy of the adult of broad-leaved trees. Negative associations were observed between upper coniferous trees and lower broad-leaved trees and between upper P. jezoensis and lower P. koraiensis, suggesting that a canopy of these trees might not provide suitable environment for the survival, establishment, and growth of o lower individuals, corresponding well to Janzen-Connell hypothesis. 展开更多
关键词 Mixed coniferous-broadleaf forest O-ring statistics Spatial pattern Spatial association Null model
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Low net primary productivity of dominant tree species in a karst forest, southwestern China: first evidences from tree ring width and girth increment 被引量:1
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作者 Jian Ni Haiyang Xu Libin Liu 《Acta Geochimica》 EI CAS CSCD 2017年第3期482-485,共4页
Aboveground net primary productivity(ANPP)of two dominant species, one deciduous tree(Platycarya strobilacea) and one evergreen tree(Machilus cavaleriei),was estimated based on the tree-ring width and the girth increm... Aboveground net primary productivity(ANPP)of two dominant species, one deciduous tree(Platycarya strobilacea) and one evergreen tree(Machilus cavaleriei),was estimated based on the tree-ring width and the girth increment as well as allometric functions in a karst evergreen and deciduous broadleaved mixed forest in central Guizhou Province, southwestern China. Results showed that the ANPP increased from 1961 to 2015, especially during the last 20–30 years, but with strong variations. The deciduous tree had higher ANPP than the evergreen tree according to two kinds of estimates by the tree ring and girth increment. The averaged ANPP for these two mature trees was 2.27 kg/individual/year, ca. 8 t/ha/year considering the normal stand density. Such karst forest productivity was lower than the natural subtropical forests in China and in the world. 展开更多
关键词 Biomass increment Tree ring Girth measurement Karst evergreen and deciduous broadleaved forest Allometric functions
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Identifying Trees Species Dominance in Hulu Sedili Forest Reserve, Peninsular Malaysia Based on Lithology Type Using Geographic Information System
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作者 I. Mohd Hasmadi K. Norizah M. S. Alias 《Journal of Agricultural Science and Technology》 2010年第4期77-82,共6页
Lowland tropical forest in Peninsular Malaysia consist a valuable dipterocarp timber species. In fact, dipterocarp tree species growth well when the ecology is maintained and their growth are dependent on the micro cl... Lowland tropical forest in Peninsular Malaysia consist a valuable dipterocarp timber species. In fact, dipterocarp tree species growth well when the ecology is maintained and their growth are dependent on the micro climate and also affected by lithology types. This study was carried out to identify and map tree species dominancy by lithology types at Hulu Sedili Forest Reserve (HSFR) using Geographic Information System (GIS) technique. Different lithology type maps were derived namely Igneous, Sedimentary and Limestone. Through GIS operations tree species data collected from pre-felling inventory and ground survey were overlaid with lithology features. Results showed that at Sedimentary and Igneous types, the presence of dipterocarpaceae family is only 3.09%, and non-dipterocarpaceae family was 96.91%. Syzygium spp. (19.83%) was the most abundance in Igneous and Sedimentary. Meanwhile, Elateriospermum tapos (9.92%) and Lauraceae's family (7.22%) were found to be the most dominant species in Sedimentary types, Macaranga spp. (11.21%) and Elateriospermum tapos (11.02%) in igneous types. However, a Limestone type was discarded from analysis due to unavailable pre-felling data. Thus, this study indicated that there was variation in species dominancy of different lithology types. On the other hand, GIS demonstrated its capability as a useful tool in identifying and maps the location of trees species based on lithology types. 展开更多
关键词 GIS (Geographic Information System) forest reserve lithology types dominance species mappmg
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基于图编辑距离的恶意代码检测 被引量:4
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作者 杨帆 张焕国 +1 位作者 傅建明 沈志东 《武汉大学学报(理学版)》 CAS CSCD 北大核心 2013年第5期453-457,共5页
传统的恶意代码检测方法漏报率高且运行效率低,很大程度的依赖于人工检测.为解决该问题,基于恶意代码自身的函数调用顺序及程序结构特征,通过静态分析技术将恶意代码抽象为函数调用图,采用图的编辑距离作为恶意代码间相似度的评估标准,... 传统的恶意代码检测方法漏报率高且运行效率低,很大程度的依赖于人工检测.为解决该问题,基于恶意代码自身的函数调用顺序及程序结构特征,通过静态分析技术将恶意代码抽象为函数调用图,采用图的编辑距离作为恶意代码间相似度的评估标准,将恶意代码的分类识别转化为在已建立的恶意代码图数据库中搜索最小编辑距离邻居图的问题,在此基础上实现了用户检测未知文件恶意性的系统.为了提高检测速度,引入了函数对应的汇编指令集和多路优势点树的高维索引算法.实验证明,该方案兼顾了恶意代码检测的准确性和运行效率. 展开更多
关键词 恶意代码检测 函数调用图 图编辑距离 多路优势
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