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Community Structure and Diversity Distributions of Small Mammals in Different Sample Plots in the Eastern Part of Wuling Mountains 被引量:13
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作者 刘井元 杜红 +3 位作者 田耕百 余品红 王身文 彭红 《Zoological Research》 CAS CSCD 北大核心 2008年第6期637-645,共9页
Five years' (2000-2004) continuous study has been carried out on small mammals such as rodents in seven different sample plots, at three different altitudes and in six different ecological environment types in the ... Five years' (2000-2004) continuous study has been carried out on small mammals such as rodents in seven different sample plots, at three different altitudes and in six different ecological environment types in the eastern part of the Wuling Mountains, south bank of the Three Gorges of Yangtze River in Hubei. A total of 29 297 rat clamps/times were placed and 2271 small mammals such as rodents were captured, and 26 small mammals were captured by other means. All the small mammals captured belonged to 8 families 19 genera and 24 species, of which rodentia accounted for 70.83% and insectivora 29.17%. Through analysis of the data, the results showed that: 1 ) although the species richness had a trend of increasing along different sample plots as altitude increased from south to north, quite a few species showed a wide habitat range in a vertical distribution ( 15 species were dispersed over three zones and two species over two zones) , indicating a strong adaptability of small mammals such as rOdents at lower altitudes in most areas and comparatively less vertical span of entire mountains; 2) whether in seven different sample plots or six different ecological types, Apodemus agrarius and Rattus norvegicus were dominant species below 1200m, and Anourosorex squamipes, Niviventer confucianus and Apodemus draco were dominant above altitudes of 1300m, however, in quantity they were short of identical regularity, meaning they did not increase as the altitude did, or decrease as the ecological areas changed; 3)the density in winter was obviously greater than that in spring, and the distribution showed an increasing trend along with altitude, but the density in different sample plots was short of identical regularity, showing changes in different seasons and altitude grades had an important impact on small mammals such as rodents; 4) in species diversity and evenness index, there were obvious changes between the seven different sample plots, probably caused by frequent human interference in this area. Comparatively speaking, there was less human interference at high altitudes where vegetation was rich and had a high diversity and evenness index, and the boundary effect and community stability were obvious. Most ecological types have been seriously interfered with due to excessive assart at low altitudes with singular vegetation and low diversity and evenness index and poor community stability, showing an ecosystem with poor anti-reversion. If human interference can be reduced in those communities at high altitudes with low diversity and evenness index, the biological diversity in the communities will gradually recover to similar levels of other ecological areas. 展开更多
关键词 Small mammals Community structure Species diversity Sample plots Eastern part of Wuling Mountains
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用Chi-Plots分析次贷危机后美国股市对欧亚主要股市的传导效应
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作者 张晓东 《昆明理工大学学报(理工版)》 北大核心 2009年第3期109-111,116,共4页
以美国次贷危机爆发为时间点,以道琼斯指数,英国金融时报FTSE100指数,香港恒生指数分别作为美国、欧洲、亚洲的股市代表,用Matlab绘制Chi-Plots图的方法来分析美国股市对欧洲亚洲股市的传导效应.
关键词 传导效应 次贷危机 Chi—plots
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Fischer Plots of Wumishan Cyclothems,Precambrian Records of Third-OrderSea-Level Changes 被引量:11
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作者 Mei Mingxiang Faculty of Earth Sciences and Mineral Resources, China University of Geosciences, Beijing 100083 Ma Yongsheng China Petrochemical Corporation (SINOPEC), Beijing 100029 Zhou Hongrui Du Benming Luo Zhiqing Guo Qingyin Faculty of Earth Sc 《Journal of China University of Geosciences》 SCIE CSCD 2001年第1期1-10,共10页
The Mesoproterozoic Wumishan Formation ((1310 ± 20 ) Ma - (l 207 ± 10) Ma) in Jixian, Tianjin represents a succession of 3 300 meter thick carbonate strata where are the best developed stromatolite biostrom... The Mesoproterozoic Wumishan Formation ((1310 ± 20 ) Ma - (l 207 ± 10) Ma) in Jixian, Tianjin represents a succession of 3 300 meter thick carbonate strata where are the best developed stromatolite biostromes and thrombolite bioherms. These biostromes and bioherms, together with tidal-flat dolomites and muddy dolostones, form Wumishan cyclothems with approximately symmetrical faciessuccession fabrics, which belong to carbonate meter-scale cyclic sequences of peritidal type. These cyclothems are overlain by lagoon dolomitic mudstones and shales and by frequently developed paleosol layers, indicating that the boundary of Wumishan cyclothems is marked by an instantaneously-exposed punctuated surface. Viewed form the regularly vertical stacking patterns of Wumishan cyclothems in long-term sequences, 26 third-order sequences may be discerned in Wumishan Formation. These thirdorder sequences may also be incorporated into six second-order sequences. In order to study the variation range of third-order sea-level changes and the formation period of third-order sequence, 626 cyclothems are discerned in the middle and upper parts of Wumishan Formation where the outcrops are well developed. In terms of the total thickness and the formation period of Mesoproterozoic Wumishan Formation, the crust subsidence rate in the sedimentary period of Wumishan Formation is supposed to be 3 meters at each interval of 100 thousands years. Based on this assumption, Fischer plot might be designed to simulate the third-order sea-level changing pattern. 展开更多
关键词 Wumisban cyclothems Fischer plots MESOPROTEROZOIC Jixian of Tianjin.
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Classification of Short Time Series in Early Parkinson’s Disease With Deep Learning of Fuzzy Recurrence Plots 被引量:9
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作者 Tuan D.Pham Karin Wardell +1 位作者 Anders Eklund Goran Salerud 《IEEE/CAA Journal of Automatica Sinica》 EI CSCD 2019年第6期1306-1317,共12页
There are many techniques using sensors and wearable devices for detecting and monitoring patients with Parkinson’s disease(PD).A recent development is the utilization of human interaction with computer keyboards for... There are many techniques using sensors and wearable devices for detecting and monitoring patients with Parkinson’s disease(PD).A recent development is the utilization of human interaction with computer keyboards for analyzing and identifying motor signs in the early stages of the disease.Current designs for classification of time series of computer-key hold durations recorded from healthy control and PD subjects require the time series of length to be considerably long.With an attempt to avoid discomfort to participants in performing long physical tasks for data recording,this paper introduces the use of fuzzy recurrence plots of very short time series as input data for the machine training and classification with long short-term memory(LSTM)neural networks.Being an original approach that is able to both significantly increase the feature dimensions and provides the property of deterministic dynamical systems of very short time series for information processing carried out by an LSTM layer architecture,fuzzy recurrence plots provide promising results and outperform the direct input of the time series for the classification of healthy control and early PD subjects. 展开更多
关键词 Deep learning early Parkinson’s disease(PD) fuzzy recurrence plots long short-term memory(LSTM) neural networks pattern classification short time series
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Impacts of Excessive Soaking on N, P, and K in Substrates Plots and Seedling Growth
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作者 王甲辰 左强 +4 位作者 谷佳林 肖强 邹国元 张琳 王美菊 《Agricultural Science & Technology》 CAS 2012年第1期158-161,180,共5页
[Objective] The aim was to study on impacts of excessive soaking N, P, and K insubstrate plots of and seedling growth. [Method] Substrate was designed to add additional 1/2 water after saturation and expansion. Dispos... [Objective] The aim was to study on impacts of excessive soaking N, P, and K insubstrate plots of and seedling growth. [Method] Substrate was designed to add additional 1/2 water after saturation and expansion. Disposable excessive soak- ing and regression relation of nutrition infusion of substrate plots were studied by design of 13 time gradient. Plant nutrition absorption and growth effects after sub- strate plots immersed by water were investigated by growing tomato. [Result] Con- centration and time of the three nutrition immersed in water had the regression equation of each, as follows: N=-2E-05t2+0.016 lt+2.0553, P=0.002 2t+2.248 5 and K=0.004 7t+0.875 8. With nutrition loss of the three, however, loss amount was al- most same with variance analysis of regression equation, which may result from its volatilization. Regression equations of P and K were: P=0.125 7t-0.117, and K=0.022 5t.1514, which led to adverse impact on plant absorption of N and K above ground, whose equations were N=20.64e-4E-0.4t, and K=E-06t2-0.011 3t+29.055. Meanwhile, un- der the condition, sound seedling index was not impacted a lot by excessive immer- sion. [Conclusion] This study has provided theoretical reference for guidance of sub- strate plot soaking method, cultivation and regulation, and breeding, as well as agri- cultural production. 展开更多
关键词 Substrate plot Saturation and expansion for absorption Excessive water Regression equation
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Application of SWAT99.2 to sensitivity analysis of water balance components in unique plots in a hilly region
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作者 Jun-feng Dai Jia-zhou Chen +3 位作者 Guo-an Lu Larry C. Brown Lei Gan Qin-xue Xu 《Water Science and Engineering》 EI CAS CSCD 2017年第3期209-216,共8页
Although many sensitivity analyses using the soil and water assessment tool(SWAT) in a complex watershed have been conducted, little attention has been paid to the application potential of the model in unique plots. I... Although many sensitivity analyses using the soil and water assessment tool(SWAT) in a complex watershed have been conducted, little attention has been paid to the application potential of the model in unique plots. In addition, sensitivity analysis of percolation and evapotranspiration with SWAT has seldom been undertaken. In this study, SWAT99.2 was calibrated to simulate water balance components for unique plots in Southern China from 2000 to 2001, which included surface runoff, percolation, and evapotranspiration. Twenty-one parameters classified into four categories, including meteorological conditions, topographical characteristics, soil properties, and vegetation attributes, were used for sensitivity analysis through one-at-a-time(OAT) sampling to identify the factor that contributed most to the variance in water balance components. The results were shown to be different for different plots, with parameter sensitivity indices and ranks varying for different water balance components. Water balance components in the broad-leaved forest and natural grass plots were most sensitive to meteorological conditions, less sensitive to vegetation attributes and soil properties, and least sensitive to topographical characteristics. Compared to those in the natural grass plot, water balance components in the broad-leaved forest plot demonstrated higher sensitivity to the maximum stomatal conductance(GSI) and maximum leaf area index(BLAI). 展开更多
关键词 Forest and GRASS plots WATER balance Sensitivity analysis Soil and WATER assessment tool (SWAT) One-at-a-time (OAT) method
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A Technique to Analyse Succession Data from Permanent Plots
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作者 Zhang Jintun(Department of Biologicaal Science,Shanxi University,Taiyuan 030006) 《生物数学学报》 CSCD 北大核心 1996年第4期1-5,共5页
Data from vegetation succession study is usually a matrix of plot × species × time.It is difficult to analyse this kind of data at present.A simple technique,clustercentering ordination is described in this ... Data from vegetation succession study is usually a matrix of plot × species × time.It is difficult to analyse this kind of data at present.A simple technique,clustercentering ordination is described in this paper,which can be used to analyse such a matrix directly.The data of 5 permanent plots in 7 years of inlands and grasslands in Kootwijki,the Netherlands,is analysed using this method as an application example.The results obviously illustrate the trend,direction and speedof community succession and can be easily interbrated.This suggests that clustercentering ordination is an effective and time-saving technique in study of vegetation succession. 展开更多
关键词 VEGETATION SUCCESSION NUMERICAL methods PERMANENT plots Clustercentering ORDINATION
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Parallel coordinate plots of maize traits under different magnesium applications
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作者 Jan Bocianowski Piotr Szulc Kamila Nowosad 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2015年第3期593-597,共5页
The parallel coordinate plot is proposed as an efficient tool for visualization of 13 traits of "stay-green" maize(Zea mays L.) cultivar exposed to different methods of magnesium application. The field experiment ... The parallel coordinate plot is proposed as an efficient tool for visualization of 13 traits of "stay-green" maize(Zea mays L.) cultivar exposed to different methods of magnesium application. The field experiment was conducted in the Department of Agronomy, Poznań University of Life Sciences, on the fields of the Department of Teaching and Experimental Station in Swadzim in 2006–2008. Experiment was conducted as a single-factor experiment with seven applications of magnesium in a randomized complete block design with four replicates. The highest mean values of grain yield and 1 000-grain weight were obtained after application of variant T3 of magnesium(10 kg MgO ha^–1 soil) in the all three years of study. 展开更多
关键词 MAGNESIUM MAIZE parallel coordinate plots VISUALIZATION
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A Reinterpretation of Historic Aquifer Tests of Two Hydraulically Fractured Wells by Application of Inverse Analysis, Derivative Analysis, and Diagnostic Plots
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作者 Patrick A. Hammond Malcolm S. Field 《Journal of Water Resource and Protection》 2014年第5期481-506,共26页
Aquifer test methods have greatly improved in recent years with the advent of inverse analysis, derivative analysis, and diagnostic plots. Updated analyses of past aquifer tests allow for improved interpretations of t... Aquifer test methods have greatly improved in recent years with the advent of inverse analysis, derivative analysis, and diagnostic plots. Updated analyses of past aquifer tests allow for improved interpretations of the data to enhance the knowledge and the predictive capabilities of the flow system. This work thoroughly reanalyzes a series of pre- and post-hydraulic fracturing, single-well aquifer tests conducted in two crystalline rock wells in New Hampshire as part of an early 1970’s study. Previous analyses of the data had relied on older manual type-curve methods for predicting the possible effects of hydraulic fracturing. This work applies inverse analysis, derivative analysis, and diagnostic plots to reanalyze the 1970’s aquifer test data. Our results demonstrate that the aquifer tests were affected by changes in flow regimes, dewatering of the aquifer and discrete fractures, and changes due to well development. Increases in transmissivities are related to well development prior to hydraulic fracturing, propagation of a single, vertical fracture hydraulically connecting the two wells after stimulation and expansion of troughs of depression. After hydraulic fracturing, the estimated total yield of the individual wells increased by 2.5 times due to the hydraulic fracturing. However, the wells may be receiving water from the same source, and well interference may affect any significant increase in their combined yield. Our analyses demonstrate the value in applying inverse analysis, derivative analysis, and diagnostic plots over the conventional method of manual type-curve analysis. In addition, our improvement in the aquifer test interpretation of the 1970’s test data has implications for more reliable estimates of sustained well yields. 展开更多
关键词 Aquifer-Test ANALYSIS Inverse ANALYSIS Derivative ANALYSIS DIAGNOSTIC plots Hydraulic FRACTURING
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Using Three-Dimensional Lorenz Scatter Plots to Detect Patients with Atrioventricular Node Double Path Caused by Interpolated Ventricular Premature Systoles: A Case Study
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作者 Li Jingxiu Zhang Fujun +1 位作者 Wei Xijin Peng Ding 《Cardiovascular Innovations and Applications》 2021年第2期301-306,共6页
A series of related electrophysiology phenomena can be caused by the occurrence of interpolated ventricular premature contraction.In our recent three-dimensional Lorenz R-R scatter plot research,we found that atrioven... A series of related electrophysiology phenomena can be caused by the occurrence of interpolated ventricular premature contraction.In our recent three-dimensional Lorenz R-R scatter plot research,we found that atrioventricular node double path caused by interpolated ventricular premature contraction imprints a specifi c pattern on three-dimensional Lorenz plots generated from 24-hour Holter recordings.We found two independent subclusters separated from the interpolated premature beat precluster,the interpolated premature beat cluster,and the interpolated premature beat postcluster,respectively.Combined with use of the trajectory tracking function and the leap phenomenon,our results reveal the presence of the atrioventricular node double conduction path. 展开更多
关键词 Three-dimensional Lorenz scatter plots interpolated ventricular premature contractions atrioventricular node double conduction path
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Wasteland and Empty Plots Trivialization in the Maradi City (Niger): Between Environmental Degradation and Consequent Nuisance, Quality of life and Sustainability of Biodiversity
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作者 Karimou Dia Hantchi Oumarou Zango +2 位作者 Amadou Oumarou Boubé Morou Moussa Konaté 《Occupational Diseases and Environmental Medicine》 2022年第1期13-34,共22页
The trivialization of empty spaces has long been practiced in the city of Maradi (Niger), particularly in the Zaria 2 (Commune II) and Ali Dan Sofo (Commune III) districts. With stalls in the streets and illegal dumpi... The trivialization of empty spaces has long been practiced in the city of Maradi (Niger), particularly in the Zaria 2 (Commune II) and Ali Dan Sofo (Commune III) districts. With stalls in the streets and illegal dumping grounds, empty plots and the surrounding areas are fairly privileged sources of various wastes. This study aims at analyzing the impact of these empty plots on the local population, through several aspects, especially in terms of the modes of occupation, internal and surrounding practices, physical environment and biodiversity, sanitation and elimination of waste. To do so, two methodological approaches were used: a survey on local population and in situ observation of these spaces. The results not only reveal a difficult proximity situation to the unbuilt but also showed that empty plots constitute not only a form of vegetation conservation for the future as well as clean surfaces which would be called upon to characterize the potential recharge of groundwater. The most potentially useful organic waste would be that of Kadro, especially feathers from poultry that could be used as compost in the fields. In addition to the degradation of urban environments (63% of respondents), the unbuilt area also contributes to poverty reduction and increases food security (69% of respondents). To reduce the negative impacts, the rewarding strategies would be awareness-raising and monitoring measures coupled with a policy of protection and environmental remedies. 展开更多
关键词 Urban Environment Empty plots BIODIVERSITY Waste Impacts Maradi NIGER
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Timed RR-interval Scatter Plots and Reverse Technology 被引量:6
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作者 Jin-tao XIANG 《Current Medical Science》 SCIE CAS 2020年第6期1191-1202,共12页
Lorenz-RR scatter plot has an obvious shortcoming in that it does not indicate the time when the scatter point happens.On the Lorenz RR scatter plot,one cannot know the time during which the cardiac rhythms take place... Lorenz-RR scatter plot has an obvious shortcoming in that it does not indicate the time when the scatter point happens.On the Lorenz RR scatter plot,one cannot know the time during which the cardiac rhythms take place.Since occurrence of cardiac rhythms is time-related,time should be introduced to such plots.In this study,time was used as abscissa and RR interval(the time interval between the previous RR wave and the R wave)as the ordinate and time was compressed into a visually observable length,and thereby a timed RR-interval scatter plot,or t-RR scatter plot,for short,was developed.On t-RR scatter plot,the patterns were band-shaped or were of linear type.On the t-RR plot,the sinus rhythm presented bands of various widths,with the spiculate or burred upper and lower boundaries,having diurnal variation.Premature beats showed separate layers(“stratification”),the layer number corresponding the number of RR-intervals.With simple premature beats,the layers were clearly separated.With parasystole rhythm,the upper and lower bands or layers might become thicker.With arial premature beats,the space or distance between layers varied.Ventricular premature beats presented equal space or distance between layers.With tachycardia,the lower layer became a“solid”layer.With atrial fibration,the“stratification”disappeared,presenting thicker or widened layers or bands,with neat lower boundary.With atrial flutter,the layers went parallel,with the layers being evenly separated or some distances being exact multiples of others.The second degree atrioventricular block displayed two layers,the lower and upper bands being equally away from the X-axis,presenting a straight line(pacing at a fixed rate)or a thicker or wider bands,with a neat upper boundary(the lowest pacing rate).When the scatter plot presented uncharacteristic patterns or had some scattered points,which rendered diagnosis difficult,a reverse technology could be used.Briefly,upon selection of scattered points,they were subjected to computerization,by regression,to reveal the piece of electrocardiogram(ECG)containing an R wave(QRS complex).Then ECG was analyzed to diagnose the cardiac rhythms.In conclusion,t-RR is a novel methodology which helps us understand heart rhythms from a new perspective. 展开更多
关键词 ELECTROCARDIOGRAM dynamic electrocardiogram REVIEW timed RR-interval scatter plot METHODOLOGY
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Airborne Acoustic Transmission and Terrain Topography at SAINTGITS Amphitheatre:An Analysis of Outdoor Auditory Perception and Comparison of Contour Plots 被引量:1
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作者 Jacob Thottathil Varghese Sajan Thomas +2 位作者 Joselin Herbert Chacko Preno Koshy Arjun Venugopal 《Sound & Vibration》 EI 2022年第3期255-274,共20页
The arrangement of natural and physical features on the earth’s surface are a few among the countless items that govern the airborne acoustic transmission at boundary layers.In particular,if the acoustic waves are at... The arrangement of natural and physical features on the earth’s surface are a few among the countless items that govern the airborne acoustic transmission at boundary layers.In particular,if the acoustic waves are attributes of live concerts at open-air theatres,without losing the sheen and quality,the audience should certainly receive the unbroken depth of the performance.Hence,at all times,it is advisable to analyse the auditory receptiveness,particularly in all intended recreational spaces.The current pandemic circumstances and the mandated COVID-19 prevention protocols encourage gatherings in naturally ventilated outdoor regions than confined indoors.This work predicts and quantifies the acoustic experience at the naturally carved amphitheatre at SAINTGITS,an autonomous institution at the down South-West of the Indian Subcontinent.The entire recreational space at SAINTGITS AMPHI was separately modelled as a Base case and Advanced case,and were analysed using the acoustic modelling module of EASE Focus,a renowned simulation freeware,which is in strict adherence with the International standards.The variation in loudness received at the nearest and farthest ends of the amphitheatre was between 67 to 80 dB.Though the Zero frequency SPL(Z-weighting)exhibited the loudness in the range of 81 to 85 dB and could maintain a safer auditory level for any human ear,it was confined to a hemispherical region near the sound source.A vertical beam angle of−4.0°was found to be effective throughout.The procedures and analyses will certainly help the future organizers and stakeholders to effectively plan the resources to reap rich acoustic experience at terrain-centric locales.The surface topography and contours were plotted with another set of freeware,the CADMAPPER and the QUIKGRID,to compare terrain gradient with the known data.Furthermore,this interdisciplinary research exhibits the extensive simulation capability of both EASE Focus and QUIKGRID and demonstrates the modelling versatility and deliverable potential of these freeware to benefit the budding architects and researchers. 展开更多
关键词 Acoustic airborne transmission Sound Pressure Level(SPL) Amphitheatre SAINTGITS contour plot terrain topology safe acoustics
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Establishment of Permanent Sample Plots and Analysis of Stand Characteristics for Interior Douglas-Fir Forests
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作者 宫伟光 PeterL.Marshall 《Journal of Forestry Research》 SCIE CAS CSCD 1997年第1期23-26,共4页
In order to study the dynamics of uneven-aged stands of interior Douglas-fir, Pseudotsuga menzesii var.glouca (Mirb.) Franco in future, six permanent sample plots wer set up on the Knife Creek Block of the Alex Fraser... In order to study the dynamics of uneven-aged stands of interior Douglas-fir, Pseudotsuga menzesii var.glouca (Mirb.) Franco in future, six permanent sample plots wer set up on the Knife Creek Block of the Alex Fraser Researh Forcst of University of British Columbia. The measurements and observations for all living trees within theboundaries of a plot wer madc, including DBH(diameter at breast height), TTH(total tree height), height to lowest livingbranch, crown diameter, tree vigor, angle of lean, distance of lean, direction of lean and tree location. Based on the data,some stand characteristics of the plots were analyzed simply and preliminarily. Results showed that most of the interiortrees on the plots are ranged 10-20 cm in distribution of DBH class, and 2-6 m in distribution of rm class. Trees withdifferent fors, however, are distributed unevenly. The relationship between total tree height and diameter at breast heightfollows a quadratic distribution, Y=a+bX+cX2. 展开更多
关键词 Permanent sample plot Stand analysis DOUGLAS-FIR
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Two Probability Plots of the Three-Parameter Lognormal Distribution
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作者 蒋仁言 《Journal of Donghua University(English Edition)》 EI CAS 2014年第6期757-759,共3页
The two-parameter lognormal distribution is a variant of the normal distribution and the three-parameter lognormal distribution is an extension of the two-parameter lognormal distribution by introducing a location par... The two-parameter lognormal distribution is a variant of the normal distribution and the three-parameter lognormal distribution is an extension of the two-parameter lognormal distribution by introducing a location parameter. The Q-Q plot of the three-parameter lognormal distribution is widely used. To obtain the Q-Q plot one needs to iteratively try different values of the shape parameter and subjectively judge the linearity of the Q-Q plot. In this paper,a mathematical method was proposed to determine the value of the shape parameter so as to simplify the generation of the Q-Q plot. Then a new probability plot was proposed,which was more easily obtained and provided more accurate parameter estimates than the Q-Q plot. These are illustrated by three realworld examples. 展开更多
关键词 three-parameter lognormal distribution probability plot correlation coefficient model selection parameter estimation
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Marginal Distribution Plots for Proportional Hazards Models with Time-Dependent Covariates or Time-Varying Regression Coefficients
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作者 Qiqing Yu Junyi Dong George Wong 《Open Journal of Statistics》 2017年第1期92-111,共20页
Given a sample of regression data from (Y, Z), a new diagnostic plotting method is proposed for checking the hypothesis H0: the data are from a given Cox model with the time-dependent covariates Z. It compares two est... Given a sample of regression data from (Y, Z), a new diagnostic plotting method is proposed for checking the hypothesis H0: the data are from a given Cox model with the time-dependent covariates Z. It compares two estimates of the marginal distribution FY of Y. One is an estimate of the modified expression of FY under H0, based on a consistent estimate of the parameter under H0, and based on the baseline distribution of the data. The other is the Kaplan-Meier-estimator of FY, together with its confidence band. The new plot, called the marginal distribution plot, can be viewed as a test for testing H0. The main advantage of the test over the existing residual tests is in the case that the data do not satisfy any Cox model or the Cox model is mis-specified. Then the new test is still valid, but not the residual tests and the residual tests often make type II error with a very large probability. 展开更多
关键词 Cox’s Model TIME-DEPENDENT COVARIATE SEMI-PARAMETRIC SET-UP Diagnostic PLOT
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Analysis of Key Features of Non-Linear Behavior Using Recurrence Plots. Case Study: Urban Pollution at Mexico City
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作者 Marco A. Aceves-Fernandez Jesus Carlos Pedraza-Ortega +3 位作者 Artemio Sotomayor-Olmedo Juan M. Ramos-Arreguín Jose Emilio Vargas-Soto Saul Tovar-Arriaga 《Journal of Environmental Protection》 2012年第9期1147-1160,共14页
The use of Recurrence plots have been extensively used in various fields. In this work, Recurrence Plots (RPs) investigates the changes in the non-linear behaviour of urban air pollution using large datasets of raw da... The use of Recurrence plots have been extensively used in various fields. In this work, Recurrence Plots (RPs) investigates the changes in the non-linear behaviour of urban air pollution using large datasets of raw data (hourly). This analysis has not been used before to extract information from large datasets for this type non-linear problem. Two different approaches have been used to tackle this problem. The first approach is to show results according to monitoring network. The second approach is to show the results by particle type. This analysis shows the feasibility of using Recurrence Analysis for pollution monitoring and control. 展开更多
关键词 RECURRENCE PLOT AIR Quality AIR POLLUTION Modelling ATMOSPHERIC POLLUTION RECURRENCE Quantification ANALYSIS
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Integrated Assessment of Cardiac PET/MRI: Co-Registered PET and MRI Polar Plots by Mutual MR-Based Segmentation of the Left Ventricular Myocardium
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作者 Felix Nensa Thorsten D. Poeppel +6 位作者 Ercan Tezgah Philipp Heusch Kai Nassenstein Michael Forsting Andreas Bockisch Raimund Erbel Thomas Schlosser 《World Journal of Cardiovascular Diseases》 2017年第4期91-104,共14页
Background: In the present study, we sought to describe a procedure for the creation of co-registered positron emission tomography (PET) and magnetic resonance imaging (MRI) polar plots of cardiac PET/MRI examinations... Background: In the present study, we sought to describe a procedure for the creation of co-registered positron emission tomography (PET) and magnetic resonance imaging (MRI) polar plots of cardiac PET/MRI examinations, validate the resulting plots against available standard methods in patients with myocardial infarction and provide examples that demonstrate the advantage of the novel approach over existing standards. Methods: Co-registered LGE and PET short-axis images were transformed into polar maps based on a radial sampling pattern. LGE was automatically detected using an automated thresholding algorithm (ATA). In 20 PET/MRI examinations in patients with acute myocardial infarction, agreement between manual LGE assessment and the ATA classification was calculated. Also agreement between MRI-segmentation based PET polar plots and standard PET polar plots (created with the Corridor4DM software package) was assessed. Results: No statistically significant difference in infarct sizes between manual and ATA segmentation was found (p = 0.12). Both methods were highly correlated (Pearson’s r = 0.96, p Conclusion: A straightforward software approach for the creation of co-registered PET and MRI polar plots was described and successfully demonstrated in PET/MRI studies of myocardial infarction and inflammation. 展开更多
关键词 CARDIAC PET/MRI Bull’s Eye POLAR PLOT POLAR Map
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Influence of the Fitted Straight Line for Confidence Bands Algorithm in Q-Q Plots
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作者 Sonia Castillo-Gutiérrez María Dolores Estudillo-Martínez Emilio Damián Lozano-Aguilera 《Open Journal of Statistics》 2021年第6期925-930,共6页
Confidence bands in a Normal Q-Q Plot allow us to detect non-normality of a data set rigorously, and in such a way that the conclusion does not depend on the subjectivity of the observer of the graph. In the construct... Confidence bands in a Normal Q-Q Plot allow us to detect non-normality of a data set rigorously, and in such a way that the conclusion does not depend on the subjectivity of the observer of the graph. In the construction of the graph, it is usual to fit a straight line to the plotted points, which serves both to check the hypothesis of normality (linear configuration of the plotted points) and to produce estimates of the parameters of the distribution. We can opt for dif-ferent types of lines. In this paper, we study the influence of five types of fitted straight lines in a Normal Q-Q Plot used for construction the confidence bands based on the exact distribution of the order statistics. 展开更多
关键词 Normal Q-Q Plot Confidence Bands Fitted Straight Line Goodness of Fit
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Assessment of the State of Forests Based on Joint Statistical Processing of Sentinel-2B Remote Sensing Data and the Data from Network of Ground-Based ICP-Forests Sample Plots
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作者 Alexander S. Alekseev Dmitry M. Chernikhovskii 《Open Journal of Ecology》 2022年第8期513-528,共16页
The research was carried out on the territory of the Karelian Isthmus of the Leningrad Region using Sentinel-2B images and data from a network of ground sample plots. The ground sample plots are located in the studied... The research was carried out on the territory of the Karelian Isthmus of the Leningrad Region using Sentinel-2B images and data from a network of ground sample plots. The ground sample plots are located in the studied territory mainly in a regular manner, laid and surveyed according to the ICP-Forests methodology with some additions. The total area of the sample plots is a small part of the entire study area. One of the objectives of the study was to determine the possibility of using the k-NN (nearest neighbor method) to assess the state of forests throughout the whole studied territory by joint statistical processing of data from ground sample plots and Sentinel-2B imagery. The data of the ground-based sample plots were divided into 2 equal parts, one for the application of the k-NN method, the second for checking the results of the method application. The systematic error in determining the mean damage class of the tree stands on sample plots by the k-NN method turned out to be zero, the random error is equal to one point. These results offer a possibility to determine the state of the forest in the entire study area. The second objective of the study was to examine the possibility of using the short-wave vegetation index (SWVI) to assess the state of forests. As a result, a close statistically reliable dependence of the average score of the state of plantations and the value of the SWVI index was established, which makes it possible to use the established relationship to determine the state of forests throughout the studied territory. The joint use and statistical processing of remotely sensed data and ground-based test areas by the two studied methods make it possible to assess the state of forests throughout the large studied area within the image. The results obtained can be used to monitor the state of forests in large areas and design appropriate forestry protective measures. 展开更多
关键词 Remote Sensing Sentinel-2B Imagery ICP-Forest Sample Plot Tree Stand Damage Class k-NN (Nearest Neighbor Method) Vegetation Index SWVI Nonlinear Regression Systematic Error Random Error
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