期刊文献+
共找到1,185篇文章
< 1 2 60 >
每页显示 20 50 100
Correlation of the quantifiable parameters of blood flow pattern derived with dynamic CT in solitary bronchogenic adenocarcinoma 被引量:8
1
作者 Shenjiang Li Xiangsheng Xiao +3 位作者 Shiyuan Liu Huimin Li Chengzhou Li Chenshi Zhang 《The Chinese-German Journal of Clinical Oncology》 CAS 2007年第4期345-349,共5页
Objective:To evaluate the correlation of the quantifiable parameters of blood flow pattern derived with dynamic CT in solitary bronchogenic adenocarcinoma(SBA).Methods:46 patients with solitary bronchogenic adenocarci... Objective:To evaluate the correlation of the quantifiable parameters of blood flow pattern derived with dynamic CT in solitary bronchogenic adenocarcinoma(SBA).Methods:46 patients with solitary bronchogenic adenocarcinomas (SBA)(diameter≤4 cm)underwent multi-location dynamic contrast material-enhanced(nonionic contrast material was administrated via the antecubital vein at a rate of 4 mL/s by using an autoinjector 90 mL,4×5 mm or 4×2.5 mm scanning mode with stable table were performed)serial CT.Precontrast and postcontrast attenuation on every scan was recorded.Perfusion (PBA),peak height(PHBA),ratio of peak height of the SPN to that of the aorta(BA-to-A ratio)and mean transit time(MTT)were calculated.The correlation between peak height of the aorta(PHA)and parameters of the SBA(PHBA,BA-to-A ratio,PBA,and MTT)and those among parameters of the SBA were assessed by means of linear regression analysis.Regression equation among parameters of the SBA were obtain by means of stepwise regression.Results:The correlation between the SBA peak height(PHBA,36.78 HU±12.02)and the aortic peak height(PHA)was significant(r=0.506,P<0.0001).No significant cor- relation was found between the BA-to-Apeak height ratio(15.33%±4.55)and the aortic peak height(r=0.130,P=0.388> 0.05)as it was between the SBA perfusion(PBA,31.86 mL/min/100 g±9.74)and the aortic peak height(r=0.049,P=0.749 >0.05).The SBA perfusion correlated with the PHBA and the BA-to-A peak height ratio(r=0.394,P=0.007<0.05;r=0.407, P=0.005<0.05).The PHBA correlated positively with the BA-to-A peak height ratio(r=0.781,P<0.0001).Mean transit time was 14.84 s±5.52.PBA=18.500+0.872×BA-to-A ratio.BA-to-A ratio=4.467+0.295×PHBA.Conclusion:The linear correlation between the SBA perfusion and BA-to-Aratio and that between BA-to-Aratio and PHBA can be expressed by equation. It is possible to design a simpler scanning procedure of investigation of bronchogenic adenocarcinoma angiogenesis. 展开更多
关键词 bronchogenic adenocarcinoma blood flow pattern CT quantifiable parameters linear correlation
暂未订购
Correlation Between Economic Development Level and Landscape Pattern in Beijing Peri-urban Areas 被引量:2
2
作者 Ji Xiaomei Chen Tian 《Chinese Journal of Population,Resources and Environment》 2010年第3期3-10,共8页
With the rapid changes of demographic and socio-economic structure, various ecological and environmental problems have emerged in peri-urban areas. Studies on the correlation between socio-economic development and eco... With the rapid changes of demographic and socio-economic structure, various ecological and environmental problems have emerged in peri-urban areas. Studies on the correlation between socio-economic development and eco-environmental preservation are inadequate. This paper analyzes the landscape pattern of peri-urban areas to address this issue. First, it studies the differentiation of economic development levels in Beijing peri-urban areas. Then, it explores the correlation between economic development level of each town and its landscape pattern using Pearson Correlation and grade difference indices. Furthermore, it summarizes the problems within current landscape pattern. Three conclusions are drawn from the analysis: (1) on the whole, the economic de- velopment level in Beijing peri-urban areas basically matches with landscape pattern; (2) landscape contagion degree decreases with the growth of economic development level in as much as 30% of Beijing peri-urban areas. This is an irrational phenomenon accord- ing to our judgment; (3) landscape fragmentation grades in more than half of the towns are higher than their economic development grades, suggesting that attention should be paid to excessive fragmentation of land use. 展开更多
关键词 correlation economic development level landscape pattern peri-urban areas BEIJING
在线阅读 下载PDF
Correlation between self-efficacy,parental parenting patterns,and severe depression in adolescents 被引量:2
3
作者 Bin-Feng Zhang Xiao-Yu Zhang 《World Journal of Psychiatry》 SCIE 2024年第12期1827-1835,共9页
BACKGROUND Adolescence is a critical period marked by significant psychological changes.This study explores how self-efficacy and parental parenting styles may influence the risk of severe depression among teens.The h... BACKGROUND Adolescence is a critical period marked by significant psychological changes.This study explores how self-efficacy and parental parenting styles may influence the risk of severe depression among teens.The hypothesis is that higher self-efficacy and authoritative parenting patterns will be negatively correlated with severe depression in adolescents.AIM To investigate the correlation between self-efficacy,parenting patterns and major depression in adolescents,and to provide guidance for mental intervention.METHODS Using a cross-sectional survey design,the data were collected through a questionnaire survey.Patients with major depression and healthy adolescents in the hospital control group were selected as the study objects.The General Self-Efficacy Scale,the Parenting Style Evaluation Scale,and the Beck Depression Inventory were used as research instruments.Data input and statistical analysis were performed,including descriptive statistics,correlation analysis,through SPSS software.RESULTS The study found that depressed patients had significantly lower self-efficacy than healthy controls,and parenting style was significantly associated with depressive symptoms in terms of emotional warmth and understanding,punishment severity,and denial.Specifically,parental emotional warmth and understanding were significantly negatively associated with depressive symptoms,while parental punishment severity and denial were significantly positively associated with depressive symptoms.Self-efficacy showed a significant negative correlation with depressive symptoms,indicating that higher self-efficacy had lower depressive symptoms.CONCLUSION Adolescent major depressive disorder patient was significantly associated with their parenting style and selfefficacy.Higher self-efficacy is associated with decreased depressive symptoms,so improving adolescent selfefficacy and improving parenting style are important. 展开更多
关键词 Adolescent depression SELF-EFFICACY Parental parenting patterns correlation analysis Psychological interventions
暂未订购
An Analysis of the Correlation between the Changes in Sa-tellite DNA Methylation Patterns and Plant Cell Responses to the Stress 被引量:1
4
作者 Darina A. Sokolova Galina S. Vengzhen Alexandra P. Kravets 《CellBio》 2013年第3期163-171,共9页
The differences in satellite DNA methylation pattern of corn seedlings with various spontaneous chromosome aberration yields and changes in methylation pattern of these DNA sequences under different exposure modes of ... The differences in satellite DNA methylation pattern of corn seedlings with various spontaneous chromosome aberration yields and changes in methylation pattern of these DNA sequences under different exposure modes of acute UV-C and chronic gamma-irradiations have been investigated. The obtained experimental data and the conducted correlation analysis demonstrated the significant correlation between the satellite DNA methylation pattern varieties and chromosome aberration yields under various stress exposure modes. The role of satellite DNA methylation pattern variability and its changing in key responses to stress such as mobile elements’ activation, cell’s passage of checkpoints, and homological repair was discussed. 展开更多
关键词 STRESS Response Plant Resistance Satellite DNA METHYLATION pattern Brave-Pirson Linear correlation
暂未订购
An intelligent automatic correlation method of oilbearing strata based on pattern constraints:An example of accretionary stratigraphy of Shishen 100 block in Shinan Oilfield of Bohai Bay Basin,East China 被引量:1
5
作者 WU Degang WU Shenghe +1 位作者 LIU Lei SUN Yide 《Petroleum Exploration and Development》 SCIE 2024年第1期180-192,共13页
Aiming at the problem that the data-driven automatic correlation methods which are difficult to adapt to the automatic correlation of oil-bearing strata with large changes in lateral sedimentary facies and strata thic... Aiming at the problem that the data-driven automatic correlation methods which are difficult to adapt to the automatic correlation of oil-bearing strata with large changes in lateral sedimentary facies and strata thickness,an intelligent automatic correlation method of oil-bearing strata based on pattern constraints is formed.We propose to introduce knowledge-driven in automatic correlation of oil-bearing strata,constraining the correlation process by stratigraphic sedimentary patterns and improving the similarity measuring machine and conditional constraint dynamic time warping algorithm to automate the correlation of marker layers and the interfaces of each stratum.The application in Shishen 100 block in the Shinan Oilfield of the Bohai Bay Basin shows that the coincidence rate of the marker layers identified by this method is over 95.00%,and the average coincidence rate of identified oil-bearing strata reaches 90.02% compared to artificial correlation results,which is about 17 percentage points higher than that of the existing automatic correlation methods.The accuracy of the automatic correlation of oil-bearing strata has been effectively improved. 展开更多
关键词 oil-bearing strata automatic correlation contrastive learning stratigraphic sedimentary pattern marker layer similarity measuring machine conditional constraint dynamic time warping algorithm
在线阅读 下载PDF
The circularly propagating pattern of the low-frequencyfluctuations of monthly MSL in the tropical PacificOcean and its correlation with El Nino
6
作者 Yu Jiye, Chen Shangjil and Fang Xinhua 《Acta Oceanologica Sinica》 SCIE CAS CSCD 1992年第2期205-218,共14页
The long-term time series analysis of the SST (sea surface temperature) in the Eastern Equatorial Pacific Ocean and the monthly MSL (mean sea level) in the tropical Pacific Ocean is conducted. Their quasiperiodic and ... The long-term time series analysis of the SST (sea surface temperature) in the Eastern Equatorial Pacific Ocean and the monthly MSL (mean sea level) in the tropical Pacific Ocean is conducted. Their quasiperiodic and low-frequency oscillation features are revealed. The significant periods of low-frequency fluctuations for monthly MSL in the area of 20°N-20° S are between 43. 5 months and 50. 0 months, approximating closely to 47. 6 months which is the significant period of SST in the Eastern Equatorial Pacific Ocean. From the results of space-spectral analysis, the low-frequency fluctations of monthly MSL in the tropical Pacific Ocean appear to have a anticlockwise circularly-propagating pattern, which is, the Eastern Pacific Ocean (off-shore of Mexico) →the area of NEC (North Equatorial Current) →the Western Equatorial Pacific Ocean→the area of NECC (North Equatorial Counter-Current)→the Eastern Equatorial Pacific Ocean. The phases of the pattern correspond to those of El Nino cycle. On the basis of the above results,a basic model is established with stepwise-regression method, which can forecast El Nino events by the variations of monthly MSL at a few stations in the tropical Pacific Ocean 4 months ahead. The correlation coefficient between the forecasted series and the observed one is 0. 89. 展开更多
关键词 MSL The circularly propagating pattern of the low-frequencyfluctuations of monthly MSL in the tropical PacificOcean and its correlation with El Nino Nino El
在线阅读 下载PDF
Specimen aspect ratio and progressive field strain development of sandstone under uniaxial compression by three-dimensional digital image correlation 被引量:15
7
作者 H. Munoz A. Taheri 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2017年第4期599-610,共12页
The complete stress-strain characteristics of sandstone specimens were investigated in a series of quasistatic monotonic uniaxial compression tests.Strain patterns development during pre-and post-peak behaviours in sp... The complete stress-strain characteristics of sandstone specimens were investigated in a series of quasistatic monotonic uniaxial compression tests.Strain patterns development during pre-and post-peak behaviours in specimens with different aspect ratios was also examined.Peak stress,post-peak portion of stress-strain,brittleness,characteristics of progressive localisation and field strain patterns development were affected at different extents by specimen aspect ratio.Strain patterns of the rocks were obtained by applying three-dimensional(3D) digital image correlation(DIC) technique.Unlike conventional strain measurement using strain gauges attached to specimen,3D DIC allowed not only measuring large strains,but more importantly,mapping the development of field strain throughout the compression test,i.e.in pre-and post-peak regimes.Field strain development in the surface of rock specimen suggests that strain starts localising progressively and develops at a lower rate in pre-peak regime.However,in post-peak regime,strains increase at different rates as local deformations take place at different extents in the vicinity and outside the localised zone.The extent of localised strains together with the rate of strain localisation is associated with the increase in rate of strength degradation.Strain localisation and local inelastic unloading outside the localised zone both feature post-peak regime. 展开更多
关键词 Uniaxial compression test Aspect ratio Strain patterns Digital image correlation(DIC)
在线阅读 下载PDF
Spatial correlation of pit and mound topography with canopy gaps in a virgin mixed beech forest, northern Iran 被引量:2
8
作者 Hashem Habashi 《Journal of Forestry Research》 SCIE CAS CSCD 2019年第1期295-303,共9页
In a reserved forest parcel in a virgin eastern Hyrcanian mixed beech forest,80 ha was surveyed to determine the pit and mound topography,canopy gaps and dead trees.The aim was to investigate the spatial patterns and ... In a reserved forest parcel in a virgin eastern Hyrcanian mixed beech forest,80 ha was surveyed to determine the pit and mound topography,canopy gaps and dead trees.The aim was to investigate the spatial patterns and correlation of pit and mound features with canopy gaps.Seventy-five canopy gaps and 61 pit and mound features were identified.The univariate first order nearest neighbor(R_(CE))and bivariate second order test(Ripley’s K)statistic were applied.R_(CE) statistics highlighted a general aggregation pattern for canopy gaps and pits and mounds,while pits and mounds alone were more clumped.Distances between canopy gaps were 130 m average,whereas distances between pit and mound features and dead trees were 60 and 78 m,respectively.Spatial positive correlation of canopy gaps with pits and mounds were observed with all distances.The result of spatial correlations between canopy gaps with pits and mounds confirmed that windthrows cause micro successions in fallen tree ecosystem-scale correlated with gap phase dynamics in the forest community-scale. 展开更多
关键词 PIT and mound CANOPY gap MIXED BEECH SPATIAL pattern SPATIAL correlation
在线阅读 下载PDF
Correlation analysis between characteristics under gastroscope and image information of tongue in patients with chronic gastritis 被引量:7
9
作者 SHANG Zimeng DU Zhengguang +4 位作者 GUAN Bei JI Xingyu CHEN Longchang WANG Yongji MA Yun 《Journal of Traditional Chinese Medicine》 SCIE CSCD 2022年第1期102-107,共6页
OBJECTIVE:To explore the correlation between diagnostic information of tongue and gastroscopy results of patients with chronic gastritis.METHODS:Frequent pattern growth(FP-Growth),SPSS Modeler was used to analyze the ... OBJECTIVE:To explore the correlation between diagnostic information of tongue and gastroscopy results of patients with chronic gastritis.METHODS:Frequent pattern growth(FP-Growth),SPSS Modeler was used to analyze the correlation rules between the image information of tongue parameters and the characteristics of the stomach and duodenum seen under gastroscopy.RESULTS:Ranking in order of confidence:cyanotic tongue,slippery fur,yellow fur and spotted tongue were sequently associated with both gastric antrum mucosal hyperemia or edema and gastric antrum mucosal erythema/macula.L,one value of tongue coating color,which counted among(30,60),tooth-marked tongue and b,one value of tongue coating color,which counted in the range of(5,20)were sequently associated with gastric antrum mucosal erythema/macula.A,one value of tongue body color,which counted in the range of(0,20),was related to both gastric antrum mucosal hyperemia or edema and gastric antrum mucosal erythema/macula.a,one value of tongue coating color,which counted in the range of(15,35),was associated with gastric antrum mucosal erythema/macula.There are a total of 9 strong correlation rules.CONCLUSIONS:Cyanotic tongue,slippery fur,yellow fur,the CIE Lab value of tongue coating,a,the value of tongue body color,spotted tongue,and tooth-marked tongue are all related to the gastric antrum mucosal hyperemia or edema and gastric antrum mucosal erythema/macula.The conditions of gastric mucosa could be predicted by the examination of the above related image information of tongue. 展开更多
关键词 GASTRITIS TONGUE STOMACH DUODENUM correlation of data frequent pattern growth algorithm
原文传递
Correlation between Chaotic Dynamics and Level Spacings: the Lyapunov and Dixon Dip Approaches to Highly Excited Vibration of Deuterium Cyanide
10
作者 区树清 吴国祯 《Chinese Physics Letters》 SCIE CAS CSCD 2007年第7期1841-1844,共4页
Chaotic dynamics of highly excited vibration of deuterium cyanide is explored by two independent approaches: (1) the Lyapunov analysis, based on the classical phase space for the levels, and (2) the Dixon dip ana... Chaotic dynamics of highly excited vibration of deuterium cyanide is explored by two independent approaches: (1) the Lyapunov analysis, based on the classical phase space for the levels, and (2) the Dixon dip analysis based on the concepts of pendulum dynamics and quantized levels. The results show that there is evident correlation between these two algorithms. We also propose that the reciprocal of energy difference between two nearby Dixon dips can be taken as a qualitative measure for the degree of dynamical chaos. 展开更多
关键词 DIABATIC correlation SPECTRAL patternS QUANTUM NUMBERS CLASSIFICATION QUANTIZATION MOLECULES SYSTEMS STATES
原文传递
Monitoring correlative financial data streams by local pattern similarity
11
作者 Tao JIANG Yu-cai FENG +3 位作者 Bin ZHANG Zhong-sheng CAO Ge FU Jie SHI 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2009年第7期937-951,共15页
Developing tools for monitoring the correlations among thousands of financial data streams in an online fashion can be interesting and useful work. We aimed to find highly correlative financial data streams in local p... Developing tools for monitoring the correlations among thousands of financial data streams in an online fashion can be interesting and useful work. We aimed to find highly correlative financial data streams in local patterns. A novel distance metric function slope duration distance (SDD) is proposed, which is compatible with the characteristics of actual financial data streams. Moreover, a model monitoring correlations among local patterns (MCALP) is presented, which dramatically decreases the computational cost using an algorithm quickly online segmenting and pruning (QONSP) with O(1) time cost at each time tick t, and our proposed new grid structure. Experimental results showed that MCALP provides an improvement of several orders of magnitude in performance relative to traditional naive linear scan techniques and maintains high precision. Furthermore, the model is incremental, parallelizable, and has a quick response time. 展开更多
关键词 Data mining Model Data streams correlation Local pattern pattern similarity
原文传递
Developmental Changes of GH Gene in Tan Sheep and Correlation Analysis with Slaughter Traits
12
作者 Ma Lina Ma Qing +1 位作者 Li Yingkang Wang Zhifen 《Animal Husbandry and Feed Science》 CAS 2017年第4期209-212,共4页
[ Objective] The paper was to study the differential expression of growth hormone (GH) gene in different ages and different tissues of Tan sheep. [ Method] Using real-time fluorescent quantitative PCR (RT-PCR) ass... [ Objective] The paper was to study the differential expression of growth hormone (GH) gene in different ages and different tissues of Tan sheep. [ Method] Using real-time fluorescent quantitative PCR (RT-PCR) assay, specific primers were designed according to the GH gene sequence published on Gen- Bank. With the total RNA of Tan sheep tissue as the template, the expression levels of GH gene in pectoral muscle, leg muscle and longissimus dorsi muscle at dif- ferent ages were analyzed. [ Result] In three types of muscle tissues, the expression patterns of GH gene in different tissues at the same month of age were pectoral muscle 〉 leg muscle 〉 longissimus dorsi muscle. The expression levels of GH gene were positively correlated with live weight before slaughter, carcass weight and net meat weight, and had significant positive correlation only with net meat weight ( P 〈 0.05 ). [ Conclusion ] The content of GH gene in different tissues gradually increased with the increasing months of age, and there were extremely significant differences in expression level of GH gene among different months of age or different sites (P〈0. 01). 展开更多
关键词 Tan sheep GH gene Real-time fluorescent quantitative PCR Expression pattern correlation analysis
在线阅读 下载PDF
Label correlation for partial label learning
13
作者 GE Lingchi FANG Min +1 位作者 LI Haikun CHEN Bo 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2022年第5期1043-1051,共9页
Partial label learning aims to learn a multi-class classifier,where each training example corresponds to a set of candidate labels among which only one is correct.Most studies in the label space have only focused on t... Partial label learning aims to learn a multi-class classifier,where each training example corresponds to a set of candidate labels among which only one is correct.Most studies in the label space have only focused on the difference between candidate labels and non-candidate labels.So far,however,there has been little discussion about the label correlation in the partial label learning.This paper begins with a research on the label correlation,followed by the establishment of a unified framework that integrates the label correlation,the adaptive graph,and the semantic difference maximization criterion.This work generates fresh insight into the acquisition of the learning information from the label space.Specifically,the label correlation is calculated from the candidate label set and is utilized to obtain the similarity of each pair of instances in the label space.After that,the labeling confidence for each instance is updated by the smoothness assumption that two instances should be similar outputs in the label space if they are close in the feature space.At last,an effective optimization program is utilized to solve the unified framework.Extensive experiments on artificial and real-world data sets indicate the superiority of our proposed method to state-of-art partial label learning methods. 展开更多
关键词 pattern recognition partial label learning label correlation DISAMBIGUATION
在线阅读 下载PDF
Improved angular resolution in electron backscatter diffraction analysis by use of image correlation techniques
14
作者 CUI HY Andrew GODFREY WANG W 《中国体视学与图像分析》 2008年第2期67-72,共6页
In this paper we describe a method for improving the angular resolution of the electron backscatter diffraction(EBSD) technique based on a correlative matching of EBSD patterns.Standard image interpolation methods are... In this paper we describe a method for improving the angular resolution of the electron backscatter diffraction(EBSD) technique based on a correlative matching of EBSD patterns.Standard image interpolation methods are used to detect shifts between selected regions of the EBSD patterns to an accuracy of one tenth of a pixel.Simulated data sets are used to show that such accuracy,combined with a small angle approximation in calculation of the rotation angle,allows determination of the misorientation between patterns to an accuracy of 0.01 degrees.The method is tested on samples of both single crystal aluminum and recrystallized nickel.The results demonstrate the accuracy and stability of the new method compared to the conventional method. 展开更多
关键词 图象分析 透视学 电子数据 实验研究
原文传递
Interaction enhanced inter-site hoppings for holons and interlayer exciton insulators in moiré correlated insulators
15
作者 Zijian Ma Hongyi Yu 《Chinese Physics B》 2025年第9期519-525,共7页
In moiré-patterned van der Waals structures of transition metal dichalcogenides,correlated insulators can form under integer and fractional fillings,whose transport properties are governed by various quasiparticl... In moiré-patterned van der Waals structures of transition metal dichalcogenides,correlated insulators can form under integer and fractional fillings,whose transport properties are governed by various quasiparticle excitations including holons,doublons and interlayer exciton insulators.Here we theoretically investigate the nearest-neighbor inter-site hoppings of holons and interlayer exciton insulators.Our analysis indicates that these hopping strengths are significantly enhanced compared to that of a single carrier.The underlying mechanism can be attributed to the strong Coulomb interaction between carriers at different sites.For the interlayer exciton insulator consisting of a holon and a carrier in different layers,we have also obtained its effective Bohr radius and energy splitting between the ground and the first-excited states. 展开更多
关键词 correlated insulator holon interlayer exciton insulator moirépattern
原文传递
Pattern时延差编码水声定位的时延估计研究 被引量:3
16
作者 吴永清 邬松 许枫 《声学技术》 CSCD 2014年第3期189-192,共4页
基于Pattern时延编码体制,针对水下超短基线定位系统设计了呼叫信号的正、负调频时延编码结构,并提出利用二次互相关技术进行时延估计。该方法在一定程度上能够提高呼叫方的可检测信噪比,同时在复杂环境下对信道中包括直达波在内的多径... 基于Pattern时延编码体制,针对水下超短基线定位系统设计了呼叫信号的正、负调频时延编码结构,并提出利用二次互相关技术进行时延估计。该方法在一定程度上能够提高呼叫方的可检测信噪比,同时在复杂环境下对信道中包括直达波在内的多径信号能量进行累加,能够准确地完成峰值检测,进而达到提高时延估计精度的目的。海试实验结果表明二次相关法在不同信噪比条件下能有效地抑制界面反射产生的多径干扰。 展开更多
关键词 二次互相关 pattern时延编码 水声定位
在线阅读 下载PDF
Environmental Correlates of Distribution of the 25 Broad-leaved Tree Species Indigenous to Guangdong Province,China 被引量:16
17
作者 SuZhiyao ChenBeiguang ChangYong YangJiazhi 《Forestry Studies in China》 CAS 2004年第4期23-28,共6页
Twenty-five tree species indigenous to Guangdong Province were chosen in this study to portray their distribution patterns in relation to environmental factors. Both data of species distribution and environmental fact... Twenty-five tree species indigenous to Guangdong Province were chosen in this study to portray their distribution patterns in relation to environmental factors. Both data of species distribution and environmental factors were tabulated based on a digitized map of Guangdong Province gridded at 0.5° latitude × 0.5° longitude. Grid-based diversity was mapped using DMAP, a distribution mapping program, and horizontal patterns were assessed using Kruskal-Wallis tests. The diversity center of the indige- nous tree species under study is located north of 23° N. These tree species exhibit significant latitudinal variation (P = 0.007 4), but no significant longitudinal difference (P = 0.052 2). Non-metric Multidimensional Scaling (NMS) identified five different ecological species groups, while Canonical Correspondence Analysis (CCA) showed the distribution of tree species along each of the five envi- ronmental gradients. An understanding of the environmental correlates of distribution patterns has great implication for the introduc- tion of the indigenous tree species for afforestation. 展开更多
关键词 indigenous tree species environmental correlate distribution horizontal pattern NMS CCA Guangdong Prov- ince
在线阅读 下载PDF
Intent Pattern Recognition of Lower-limb Motion Based on Mechanical Sensors 被引量:20
18
作者 Zuojun Liu Wei Lin +1 位作者 Yanli Geng Peng Yang 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2017年第4期651-660,共10页
Based on the regularity nature of lower-limb motion,an intent pattern recognition approach for above-knee prosthesis is proposed in this paper. To remedy the defects of recognizer based on electromyogram(EMG), we deve... Based on the regularity nature of lower-limb motion,an intent pattern recognition approach for above-knee prosthesis is proposed in this paper. To remedy the defects of recognizer based on electromyogram(EMG), we develop a pure mechanical sensor architecture for intent pattern recognition of lower-limb motion. The sensor system is composed of an accelerometer, a gyroscope mounted on the prosthetic socket, and two pressure sensors mounted under the sole. To compensate the delay in the control of prosthesis, the signals in the stance phase are used to predict the terrain and speed in the swing phase. Specifically, the intent pattern recognizer utilizes intraclass correlation coefficient(ICC) according to the Cartesian product of walking speed and terrain. Moreover, the sensor data are fused via DempsterShafer's theory. And hidden Markov model(HMM) is used to recognize the realtime motion state with the reference of the prior step. The proposed method can infer the prosthesis user's intent of walking on different terrain, which includes level ground,stair ascent, stair descent, up and down ramp. The experiments demonstrate that the intent pattern recognizer is capable of identifying five typical terrain-modes with the rate of 95.8%. The outcome of this investigation is expected to substantially improve the control performance of powered above-knee prosthesis. 展开更多
关键词 Above-knee prosthesis hidden Markov model(HMM) intra-class correlation coefficient(ICC) intent pattern recognition sensor fusion
在线阅读 下载PDF
Spatial distribution pattern in mammal and bird richness and their relationship with ecosystem services in Sanjiangyuan National Park, China 被引量:7
19
作者 WAN Hua-wei LI Hao-xin +1 位作者 WU Jin-hui LIU Yu-ping 《Journal of Mountain Science》 SCIE CSCD 2021年第6期1662-1677,共16页
Species diversity exhibit a close relationship with ecosystem services, and making clear the relationship can help us understand the service value and functional mechanism of ecosystems and take measures to promote hu... Species diversity exhibit a close relationship with ecosystem services, and making clear the relationship can help us understand the service value and functional mechanism of ecosystems and take measures to promote human well-being. Here, we used species survey data and multi-source habitat factors to simulate the spatial distribution of species richness and four types of ecosystem services(water production, net primary productivity, carbon storage, and habitat quality) in Sanjiangyuan National Park located in Qinghai Province, China. We also analyzed the spatial distribution pattern and explored the spatial relationship between species richness and ecosystem services through Geo Detector analyses. We found that high species richness in Sanjiangyuan National Park was shown to be mainly distributed in areas with high vegetation growth on both sides of rivers. The effect of climate on the spatial distribution of species richness in the park is the highest among all the selected environmental variables. For the relationship between species diversity and ecosystem services, the relative correlation strength of single ecosystem service varied among the three main ecosystems(grassland, meadow, and wetland) and all relations are positive. 展开更多
关键词 Sanjiangyuan National Park Species richness Ecosystem services Spatial pattern correlation
原文传递
Spatial pattern dynamics among co-dominant populations in early secondary forests in Southwest China 被引量:6
20
作者 Yuanfa Li Minghui Li +3 位作者 Angang Ming Hongxiang Wang Sufang Yu Shaoming Ye 《Journal of Forestry Research》 SCIE CAS CSCD 2021年第4期1373-1384,共12页
The canopy of subtropical natural forests usually consists of several co-dominant populations(CDPs),which play a crucial role in forest structure,formation of the forest environment,and ecological function.However,lit... The canopy of subtropical natural forests usually consists of several co-dominant populations(CDPs),which play a crucial role in forest structure,formation of the forest environment,and ecological function.However,little attention has been given to changes in spatial patterns in CDPs during natural succession.Cyclobalanopsis glauca(Thunb.)Oerst.,Quercus variabilis Blume,and Pinus yunnanensis var.tenuifolia W.C.Cheng & Y.W.Law are canopy species that form CDPs in zonal forests along the Nanpan River in southwest China.We used the g(r) function and its bivariate distribution model,g_(12)(r),which is based on distances between pairs of points,to explore the dynamics of the three CDP species with respect to distribution patterns and spatial correlations in two secondary forests(one 30-year-old forest [30-YF] and one 57-year-old forest [57-YF]).The following key results were obtained:(1) there was a clumped pattern in the 30-YF,but the intensity of aggregation varied among populations and life stages.The distribution pattern gradually shifted to become random with longer succes sion time(i.e.,30-YF vs.57-YF),expansion of the observation scale(r=0-20 m),and at later life stages.(2) Aside from the mid-sized C.glauca trees and large P.yunnanensis trees,the trees repulsed each other at certain scales(r=0-2,5-6,11-12,14-16 m) in the 30-YF.Almost all of the life stages in the CDPs were independently correlated.This independent correlation was exacerbated by a longer succession time.(3) An increase in life stages and longer succession also promoted independent changes in intraspecific correlations.(4) Intraspecific correlations were stronger than interspecific correlations.Our results showed that reducing exclusive competition is essential to coexistence in CDPs.Inter-and intra-specific repulsion may occur at the same time,but intraspecific repulsion was the main driving force behind the random distributions and independent correlations. 展开更多
关键词 Co-dominant populations COMPETITION Secondary forest Spatial correlations Distribution patterns
在线阅读 下载PDF
上一页 1 2 60 下一页 到第
使用帮助 返回顶部