DCCA

摘要： 植物群落分布格局是环境因子和人类活动共同作用的结果,尤其是海拔梯度被认为是植物群落分布格局的决定性因子,为探求甘肃祁连山国家自然保护区植物群落分布格局与环境因子的关系及其驱动机制,该文在野外调查的基础上,运用数量分类和除趋势典范对应分析(DCCA)排序等方法,探讨了研究区内植物群落特征及其与环境因子的关系。结果表明:(1)88个样方共记录物种85种,隶属30科56属,利用双向指示种分析法(TWINSPAN)将其分为9个植物群落。(2)9个植物群落在DCCA排序图上聚集分布,呈现出较好的环境梯度,其中海拔对植物群落分布格局影响最大,其次为降水、温度、坡度、坡向和土壤腐殖质。(3)影响植物群落空间分布格局的变量中,环境因子占25.24%,空间因子占13.21%,空间因子和环境因子交叉作用占9.03%,群落分布格局未被空间因子和环境因子解释部分占52.52%,这部分主要反映了人类活动对研究区植物群落分布格局的影响。该研究成果对区域内植被的生态恢复和生物多样性的稳定维持具有重要意义。

摘要： 丹江口库区为南水北调中线工程的核心水源区,本文基于库周植物群落和环境因子的实地调查,应用除趋势典范对应分析(DCCA)探究了该区群落物种分布与10个环境因子的关系.结果表明:①库周植物群落物种分布与环境因子关系密切,10个环境因子共解释了群落物种分布格局的62.7％;②土壤pH值是影响库周植物群落物种分布的关键环境因子,其次为土壤厚度和土壤养分;③筛选出侧柏、白刺花和拟金茅等20种对碱性、薄且贫瘠土壤有较好适应能力的乡土植物用于库周水源涵养林的营造.本文的研究结果可为丹江口库区的植被恢复、水源涵养与净化工作提供依据.

摘要： 以江西省寻乌县为研究靶区,运用随机森林算法(Random Forest,RF)提取了研究区不透水面的遥感信息,分析了不透水面与温度的长程互相关性,结果表明二者在F2(s)与s的双对数曲线存在三个无标度区间,且存在两个分界点,反映了二者之间的年代际长程相关性.研究结果以期为城市地表覆盖变化及其气候效应分析提供新的视角和思路.

摘要： 利用网络爬虫抓取网络中名老中医医案数据,可以为医案数据挖掘提供优质的原始数据.提出了一种基于网络爬虫的名老中医医案数据采集与清理算法DCCA(Data Collection and Cleaning Algorithm),处理了12670个网页,抽取出28813条诊次数据.与传统方法比较,DCCA的抓取效率更高、处理结果属性清晰、处理后的数据冗余度低,极大地提高了中医药网站中名老中医医案数据采集与清理效果.

摘要： 在野外调查的基础上,应用TWINSPAN,DCA和DCCA对山西华北落叶松群落进行分类和排序研究.结果表明,依据不同的指示种将40个样地分划为10个群丛:华北落叶松-三裂绣线菊-披针薹草群丛、华北落叶松-金银忍冬-披针薹草群丛、华北落叶松-土庄绣线菊+金银忍冬-披针薹草群丛、华北落叶松-小卫矛-糙苏群丛、华北落叶松-土庄绣线菊-林地早熟禾群丛、华北落叶松-刚毛忍冬-东方草莓+披针薹草群丛、华北落叶松-东北茶藨子-披针薹草群丛、华北落叶松-披针薹草群丛、华北落叶松-刚毛忍冬-北柴胡群丛和华北落叶松-银露梅-东方草莓群丛;DCA的排序结果显示,影响华北落叶松群落物种分布的主导因子是温度、海拔及水分条件;DCCA的排序结果显示,华北落叶松群落物种的分布与海拔呈正相关,与坡向呈负相关.

摘要： 与以往仅针对价格或交易量某单一序列的实证研究不同,从价-量交叉相关性视角,以金融危机期间中国股市每1分钟高频数据为研究对象,对其日内效应、长记忆性及多重分形性等异象性特征进行了研究。首先,对我国股市的日内效应进行了检验,发现该日内效应表现为"U"型形式。进一步,运用DFA和DCCA方法,研究了中国股市价格和成交量序列的长记忆性及交叉相关性特征。最后,运用MF-DFA和MF-DCCA方法对中国股市价格及交易量序列进行了多重分形分析和多重分形交叉相关分析。上述研究结果表明,中国股市价格序列与交易量序列不但自身具有显著的长记忆性及多重分形特征,且股市价-量关系之间也存在着显著的长记忆性和多重分形特征,即金融市场的价格变动不但受价格变动本身的影响,还会受到交易量变动的影响。这说明,对股市行为的分析应将价、量作为一个有机整体来全面考虑,而不是进行单独量化。

摘要： 露天矿排土场边坡水土流失严重，易发生地质灾害，急需开展生态恢复和土地复垦研究。为了解排土场边坡植物群落演替规律以及植物对生境因子的响应关系，本研究以阜新露天矿不同恢复年限排土场边坡为对象，调查不同坡向和坡位的植物组成、数量、高度和盖度，采用双向指示种法（TWINSPAN）对植物群落进行分类；同时分析边坡土壤物理、化学和生物学性质，采用去趋势典范对应分析（DCCA）方法研究群落分布格局与环境因子的关系。结果表明，排土场边坡共出现27种植物，物种数量小于平台。植物群落在阴坡和阳坡呈现出不同的演替格局，阴坡演替顺序为狗尾草（Setaira viridis）+茵陈蒿（Artemisia capillaries）+铁杆蒿（Artemisia sacrorum）→狗尾草+铁杆蒿+白蒿（Artemisia anethoides）→铁杆蒿+狗尾草；恢复10 a后，铁杆蒿在中上坡位占据优势地位，植物种类和数量下降，植物群落呈逆向演替。阳坡演替顺序为蒺藜（Tribulus terrestris）+旱稗（Echinochloa hispidula）+狗尾草→狗尾草+蒺藜+白蒿→狗尾草+页蒿（Carum carvi）+白蒿，植被演替进程缓慢。DCCA排序表明，第一轴主要反映植物群落随坡位、土壤水分、氮元素有效性和周转的变化规律，其与土壤pH值和脲酶紧密相关；第二轴主要反映植物群落随着恢复年限和土壤磷素有效性的梯度变化，其与土壤容重、速效磷、蔗糖酶和碱性磷酸酶紧密相关。排土场边坡必须采取人工恢复措施，土壤酶活性对植物群落分布影响较大。%It is necessary to carry out the research about ecological restoration and land reclamation on dump slopes of opencast coalmine, for where there remain great risks of soil and water loss and geological hazards. In order to understand the plant community succession patterns and find out relationships between vegetation and environmental factors on dump slopes, we carried out an investigation on plant communities within different successional stages on several dump slopes of opencast coalmine in Fuxin, Liaoning. Plant species composition, density, height, and coverage of different slope aspects and slope position were recorded during the survey. Soil characteristics of physics, chemistry and biology were measured also. Two-way indicators species analysis (TWINSPAN) method was used for cluster analysis of plant communities. Detrended canonical correspondence analysis (DCCA) method was employed to identify relationships between distribution patterns of plant communities and environmental factors. The results showed that richness of plant species on dump slopes (27 species totally) less than platform. Different succession patterns occurred on the slopes. The successional series on the shady slope were Setaira viridis + Artemisia capillaries + Artemisia sacrorum→S. viridis + A. sacrorum+ Artemisia anethoides→A. sacrorum + S. viridis.A. capillaries became the dominant species at the upper and middle part after 10 years’ recovery, which lead to the plant species and richness decline and regressive succession of plant communities. The succession series on the sunny slope wereTribulus terrestris + Echinochloa hispidula +S. viridis→S. viridis+T. terrestris+ A. anethoides→S. viridis + Carum carvi + A. anethoides. It suggested that the succession processes were slow. The first axis of DCCA ordination represented the slope position, soil water content, available N and its turnover gradients. And it was correlated with soil pH value and urease. The second axis of DCCA ordination reflected restoration years and gradients of soil available P. And it was related to soil bulk density, available P, invertase and alkaline phosphatase. Our results implied that artificial rehabilitation is essential for the restoration of dump slopes. The soil enzyme activity could explain most variations of species composition in communities.

摘要： 根据野外样方调查数据,采用双向种指示分析(TWINSPAN)和典范对应分析(DCCA),对珠穆朗玛峰国家级自然保护区高山杜鹃灌丛群落进行分类和排序,并分析物种多样性沿海拔梯度分布格局.结果表明:(1)该研究区域38个高山杜鹃样地中,共记载的维管束植物有35科68属135种,出现频度较高的种有高山嵩草(Kobresia pygmaea)、珠芽蓼(Polygonum viviparum)、高山大戟(Euphorbia stracheyi)、髯花杜鹃(Rhododendron anthopogon)、雪层杜鹃(R.nivale)、扫帚岩须(Cassiope fastigiata)、鳞腺杜鹃(R.lepidotum)、木根香青(Anaphalis xylorhiza)、刚毛杜鹃(R.setosum)等.(2)TWINSPAN等级分类将该区域高山杜鹃灌丛38个样地划分为14个群丛类型.(3)样地DCCA二维排序图结果表明,土壤类型和海拔是影响该区域高山杜鹃灌丛群落分布格局的主要因子.(4)该区域高山杜鹃灌丛群落物种丰富度、Shannon Wiener指数和Simpson指数与海拔呈显著负相关关系,随着海拔的升高而不断降低;而Pielou指数与海拔之间并无显著相关关系.

摘要： A greenhouse pot experiment was conducted to evaluate the effect of fungus, of citric acid, or of acombination of both, in the phytoremediation of a heavy metal contaminated soil, affected by Cd and Pb. Sixenzyme activities (namely dehydrogenase, phosphatase, urease, catalase, sucrase and amylase) in soil weredetermined in this study. Detrended Canonical Correspondence Analysis (DCCA) was taken to express therelationship between all remediation methods and soil enzyme activities in the ordination diagram to assessthe remediation effect in soil health degree. Results showed that soil enzyme activities were graduallyinhibited with increasing heavy metal concentration. In the samples without any remediation, single Pbpollution showed smaller influence on inhibition of soil enzyme activity than single Cd pollution, while Cdand Pb combined pollution showed similar changing tendency with single Cd pollution. As shown in theordination graph by DCCA, All soil enzymes variables showed big change at first axis. In a certain extent, Cdand Pb complex variables could reflect the soil enzymes activities change law at first axis due to their biggerprojections at first axis. The ordination diagrams also expressed the relationship between all remediationmethod variables and soil enzyme activity variables by their distance and position. Most of remediationmethods had positive effects on enhancing soil enzyme activities, except on sucrase activity. The soil enzymeactivities of hyperaccumulator treated with fungus were similar to that of treated with citric acid. Allremediation methods had significant positive effects on enhancing dehydrogenase, urease and catalaseactivities, whereas phosphatase and amylase activities were reduced at low heavy metal concentration andincreased at high concentration as a result of remediation in soil. All remediation methods showed negativeeffects on sucrase activity.

摘要： A greenhouse pot experiment was conducted to evaluate the effect of fungus, of citric acid, or of acombination of both, in the phytoremediation of a heavy metal contaminated soil, affected by Cd and Pb. Sixenzyme activities (namely dehydrogenase, phosphatase, urease, catalase, sucrase and amylase) in soil weredetermined in this study. Detrended Canonical Correspondence Analysis (DCCA) was taken to express therelationship between all remediation methods and soil enzyme activities in the ordination diagram to assessthe remediation effect in soil health degree. Results showed that soil enzyme activities were graduallyinhibited with increasing heavy metal concentration. In the samples without any remediation, single Pbpollution showed smaller influence on inhibition of soil enzyme activity than single Cd pollution, while Cdand Pb combined pollution showed similar changing tendency with single Cd pollution. As shown in theordination graph by DCCA, All soil enzymes variables showed big change at first axis. In a certain extent, Cdand Pb complex variables could reflect the soil enzymes activities change law at first axis due to their biggerprojections at first axis. The ordination diagrams also expressed the relationship between all remediationmethod variables and soil enzyme activity variables by their distance and position. Most of remediationmethods had positive effects on enhancing soil enzyme activities, except on sucrase activity. The soil enzymeactivities of hyperaccumulator treated with fungus were similar to that of treated with citric acid. Allremediation methods had significant positive effects on enhancing dehydrogenase, urease and catalaseactivities, whereas phosphatase and amylase activities were reduced at low heavy metal concentration andincreased at high concentration as a result of remediation in soil. All remediation methods showed negativeeffects on sucrase activity.

摘要： A greenhouse pot experiment was conducted to evaluate the effect of fungus, of citric acid, or of acombination of both, in the phytoremediation of a heavy metal contaminated soil, affected by Cd and Pb. Sixenzyme activities (namely dehydrogenase, phosphatase, urease, catalase, sucrase and amylase) in soil weredetermined in this study. Detrended Canonical Correspondence Analysis (DCCA) was taken to express therelationship between all remediation methods and soil enzyme activities in the ordination diagram to assessthe remediation effect in soil health degree. Results showed that soil enzyme activities were graduallyinhibited with increasing heavy metal concentration. In the samples without any remediation, single Pbpollution showed smaller influence on inhibition of soil enzyme activity than single Cd pollution, while Cdand Pb combined pollution showed similar changing tendency with single Cd pollution. As shown in theordination graph by DCCA, All soil enzymes variables showed big change at first axis. In a certain extent, Cdand Pb complex variables could reflect the soil enzymes activities change law at first axis due to their biggerprojections at first axis. The ordination diagrams also expressed the relationship between all remediationmethod variables and soil enzyme activity variables by their distance and position. Most of remediationmethods had positive effects on enhancing soil enzyme activities, except on sucrase activity. The soil enzymeactivities of hyperaccumulator treated with fungus were similar to that of treated with citric acid. Allremediation methods had significant positive effects on enhancing dehydrogenase, urease and catalaseactivities, whereas phosphatase and amylase activities were reduced at low heavy metal concentration andincreased at high concentration as a result of remediation in soil. All remediation methods showed negativeeffects on sucrase activity.

摘要： A greenhouse pot experiment was conducted to evaluate the effect of fungus, of citric acid, or of acombination of both, in the phytoremediation of a heavy metal contaminated soil, affected by Cd and Pb. Sixenzyme activities (namely dehydrogenase, phosphatase, urease, catalase, sucrase and amylase) in soil weredetermined in this study. Detrended Canonical Correspondence Analysis (DCCA) was taken to express therelationship between all remediation methods and soil enzyme activities in the ordination diagram to assessthe remediation effect in soil health degree. Results showed that soil enzyme activities were graduallyinhibited with increasing heavy metal concentration. In the samples without any remediation, single Pbpollution showed smaller influence on inhibition of soil enzyme activity than single Cd pollution, while Cdand Pb combined pollution showed similar changing tendency with single Cd pollution. As shown in theordination graph by DCCA, All soil enzymes variables showed big change at first axis. In a certain extent, Cdand Pb complex variables could reflect the soil enzymes activities change law at first axis due to their biggerprojections at first axis. The ordination diagrams also expressed the relationship between all remediationmethod variables and soil enzyme activity variables by their distance and position. Most of remediationmethods had positive effects on enhancing soil enzyme activities, except on sucrase activity. The soil enzymeactivities of hyperaccumulator treated with fungus were similar to that of treated with citric acid. Allremediation methods had significant positive effects on enhancing dehydrogenase, urease and catalaseactivities, whereas phosphatase and amylase activities were reduced at low heavy metal concentration andincreased at high concentration as a result of remediation in soil. All remediation methods showed negativeeffects on sucrase activity.

摘要： A greenhouse pot experiment was conducted to evaluate the effect of fungus, of citric acid, or of acombination of both, in the phytoremediation of a heavy metal contaminated soil, affected by Cd and Pb. Sixenzyme activities (namely dehydrogenase, phosphatase, urease, catalase, sucrase and amylase) in soil weredetermined in this study. Detrended Canonical Correspondence Analysis (DCCA) was taken to express therelationship between all remediation methods and soil enzyme activities in the ordination diagram to assessthe remediation effect in soil health degree. Results showed that soil enzyme activities were graduallyinhibited with increasing heavy metal concentration. In the samples without any remediation, single Pbpollution showed smaller influence on inhibition of soil enzyme activity than single Cd pollution, while Cdand Pb combined pollution showed similar changing tendency with single Cd pollution. As shown in theordination graph by DCCA, All soil enzymes variables showed big change at first axis. In a certain extent, Cdand Pb complex variables could reflect the soil enzymes activities change law at first axis due to their biggerprojections at first axis. The ordination diagrams also expressed the relationship between all remediationmethod variables and soil enzyme activity variables by their distance and position. Most of remediationmethods had positive effects on enhancing soil enzyme activities, except on sucrase activity. The soil enzymeactivities of hyperaccumulator treated with fungus were similar to that of treated with citric acid. Allremediation methods had significant positive effects on enhancing dehydrogenase, urease and catalaseactivities, whereas phosphatase and amylase activities were reduced at low heavy metal concentration andincreased at high concentration as a result of remediation in soil. All remediation methods showed negativeeffects on sucrase activity.

摘要： A greenhouse pot experiment was conducted to evaluate the effect of fungus, of citric acid, or of acombination of both, in the phytoremediation of a heavy metal contaminated soil, affected by Cd and Pb. Sixenzyme activities (namely dehydrogenase, phosphatase, urease, catalase, sucrase and amylase) in soil weredetermined in this study. Detrended Canonical Correspondence Analysis (DCCA) was taken to express therelationship between all remediation methods and soil enzyme activities in the ordination diagram to assessthe remediation effect in soil health degree. Results showed that soil enzyme activities were graduallyinhibited with increasing heavy metal concentration. In the samples without any remediation, single Pbpollution showed smaller influence on inhibition of soil enzyme activity than single Cd pollution, while Cdand Pb combined pollution showed similar changing tendency with single Cd pollution. As shown in theordination graph by DCCA, All soil enzymes variables showed big change at first axis. In a certain extent, Cdand Pb complex variables could reflect the soil enzymes activities change law at first axis due to their biggerprojections at first axis. The ordination diagrams also expressed the relationship between all remediationmethod variables and soil enzyme activity variables by their distance and position. Most of remediationmethods had positive effects on enhancing soil enzyme activities, except on sucrase activity. The soil enzymeactivities of hyperaccumulator treated with fungus were similar to that of treated with citric acid. Allremediation methods had significant positive effects on enhancing dehydrogenase, urease and catalaseactivities, whereas phosphatase and amylase activities were reduced at low heavy metal concentration andincreased at high concentration as a result of remediation in soil. All remediation methods showed negativeeffects on sucrase activity.

摘要： A greenhouse pot experiment was conducted to evaluate the effect of fungus, of citric acid, or of acombination of both, in the phytoremediation of a heavy metal contaminated soil, affected by Cd and Pb. Sixenzyme activities (namely dehydrogenase, phosphatase, urease, catalase, sucrase and amylase) in soil weredetermined in this study. Detrended Canonical Correspondence Analysis (DCCA) was taken to express therelationship between all remediation methods and soil enzyme activities in the ordination diagram to assessthe remediation effect in soil health degree. Results showed that soil enzyme activities were graduallyinhibited with increasing heavy metal concentration. In the samples without any remediation, single Pbpollution showed smaller influence on inhibition of soil enzyme activity than single Cd pollution, while Cdand Pb combined pollution showed similar changing tendency with single Cd pollution. As shown in theordination graph by DCCA, All soil enzymes variables showed big change at first axis. In a certain extent, Cdand Pb complex variables could reflect the soil enzymes activities change law at first axis due to their biggerprojections at first axis. The ordination diagrams also expressed the relationship between all remediationmethod variables and soil enzyme activity variables by their distance and position. Most of remediationmethods had positive effects on enhancing soil enzyme activities, except on sucrase activity. The soil enzymeactivities of hyperaccumulator treated with fungus were similar to that of treated with citric acid. Allremediation methods had significant positive effects on enhancing dehydrogenase, urease and catalaseactivities, whereas phosphatase and amylase activities were reduced at low heavy metal concentration andincreased at high concentration as a result of remediation in soil. All remediation methods showed negativeeffects on sucrase activity.

摘要： 本发明公开了一种基于DCCA融合特征的行人重识别方法，具体按照如下步骤实施：对行人再识别数据集进行预处理，将图像大小调整至合适大小；对与处理后的行人数据集基于vgg16深度卷积神经网络和omni‑scale深度卷积神经网络分别进行深度特征提取；对提取的深度特征做典型相关性分析，求解各自的投影矩阵，将投影后的特征根据特征融合策略进行特征融合；用融合后的特征完成整个行人重识别过程。本发明的一种基于DCCA融合特征的行人重识别方法，结合vgg16和omni‑scale深度网络的优势，提高了特征鲁棒性，融合特征的同时，有效地消除了冗余信息，提高特征判别能力，提高行人重识别的准确率。