The distributed passive measurement is an important technology for networkbehavior research. To achieve a consistent measurement, the same packets should be sampled atdistributed measurement points. And in order to es...The distributed passive measurement is an important technology for networkbehavior research. To achieve a consistent measurement, the same packets should be sampled atdistributed measurement points. And in order to estimate the character of traffic statistics, thetraffic sample should be random in statistics. A distributed samplingmask measurement model isintroduced to tackle the difficulty of measuring the full trace of high-speed networks. The keypoint of the model is to choose some bits that are suitable to be sampling mask. In the paper, thebit entropy and bit flow entropy of IP packet headers in CERNET backbone are analyzed, and we findthat the 16 bits of identification field in IP packet header are fit to the matching field ofsampling mask. Measurement traffic also can be used to analyze the statistical character ofmeasurement sample and the randomicity of the model. At the same time the experiment resultsindicate that the model has a good sampling performance.展开更多
Subtree analysis and three area satements (TASS) procedure are used to deal with the area relationship in historical biogeography. On the basis of the taxon cladogram, the procedure could identify and eliminate the ...Subtree analysis and three area satements (TASS) procedure are used to deal with the area relationship in historical biogeography. On the basis of the taxon cladogram, the procedure could identify and eliminate the paralogy node and determine the informative subtree. The area relationships are generally illustrated in several subtrees and the consensus tree. The distribution pattern of the genus Caragana comprising about 72 species and occurring in 13 areas, was analyzed by using subtree method and TASS procedure in this study. The results showed seven subtrees representing the area relationships of section and series of the genus, and the consensus tree provided the 13 area relationships. These results are congruent with our former result using component analysis for Caragana.展开更多
There is an increasing concern for potentially hazardous metals pollution, which can threaten crops production and human health. In this study, the spatial distribution and environmental risks of eight heavy metals in...There is an increasing concern for potentially hazardous metals pollution, which can threaten crops production and human health. In this study, the spatial distribution and environmental risks of eight heavy metals in surface soil samples collected from the paddy fields in Yongshuyu irrigation area, Northeast China were investigated. The mean concentrations of Pb, Cr, Cu, Ni, Zn, Cd, Hg and As were 34.6 ± 4.67, 82.8 ± 9.51, 17.3 ± 4.09, 21.2 ± 12.0, 88.6 ± 17.9, 0.18 ± 0.15, 0.22 ± 0.07 and 8.77 ± 2.47 mg/kg, respectively, which were slightly higher than their corresponding background values of Jilin Province, indicating enrichment of these metals in the paddy soils, especially for Ni, Cd and Hg. The spatial distribution of heavy metals was closely correlated with local anthropogenic activities, such as agricultural production, mining and transportation. The hot-spot areas of As and Cd were mainly concentrated in the up-midstream where were associated with agricultural activities. Cr and Cu showed similar spatial distributions with hot-spot areas distributed the whole irrigation area uniformly. Ni was mainly distributed in the downstream where Ni quarries concentrated, while the spatial distribution patterns of Hg was mainly located in the upstream and downstream where the soil was significantly influenced by irrigation and coal mining emission. The spatial distributions of Pb and Zn were mainly concentrated along the highway side. The pollution levels of Yongshuyu irrigation area were estimated through index of geo-accumulation(Igeo), Nemerow integrated pollution index(NIPI) and potential ecological risk index(PERI). The results showed that Cd and Hg were the main pollutants in the study area. Health risk assessment results indicated that children were in higher non-carcinogenic and carcinogenic risks than adults with the carcinogenic metal of As. Ingestion was the main exposure pathway to non-carcinogenic and carcinogenic risk for both adults and children. Principal component analysis(PCA) indicated that Cr and Cu were mainly from parent materials, while Cd and As were mainly affected by agricultural activities. Pb and Zn were controlled by traffic activities, and the accumulations of Ni and Hg were associated with mining activities. This study would be valuable for preventing heavy metals inputs and safety in rice production of the Songhua river basin.展开更多
This letter explores the distributed multisensor dynamic system, which has uniform sampling velocity and asynchronous sampling data for different sensors, and puts forward a new gradation fusion algorithm of multisens...This letter explores the distributed multisensor dynamic system, which has uniform sampling velocity and asynchronous sampling data for different sensors, and puts forward a new gradation fusion algorithm of multisensor dynamic system. As the total forecasted increment value between the two adjacent moments is the forecasted estimate value of the corresponding state increment in the fusion center, the new algorithm models the state and the forecasted estimate value of every moment. Kalman filter and all measurements arriving sequentially in the fusion period are employed to update the evaluation of target state step by step, on the condition that the system has obtained the target state evaluation that is based on the overall information in the previous fusion period. Accordingly, in the present period, the fusion evaluation of the target state at each sampling point on the basis of the overall information can be obtained. This letter elaborates the form of this new algorithm. Computer simulation demonstrates that this new algorithm owns greater precision in estimating target state than the present asynchronous fusion algorithm calibrated in time does.展开更多
Video reconstruction quality largely depends on the ability of employed sparse domain to adequately represent the underlying video in Distributed Compressed Video Sensing (DCVS). In this paper, we propose a novel dyna...Video reconstruction quality largely depends on the ability of employed sparse domain to adequately represent the underlying video in Distributed Compressed Video Sensing (DCVS). In this paper, we propose a novel dynamic global-Principal Component Analysis (PCA) sparse representation algorithm for video based on the sparse-land model and nonlocal similarity. First, grouping by matching is realized at the decoder from key frames that are previously recovered. Second, we apply PCA to each group (sub-dataset) to compute the principle components from which the sub-dictionary is constructed. Finally, the non-key frames are reconstructed from random measurement data using a Compressed Sensing (CS) reconstruction algorithm with sparse regularization. Experimental results show that our algorithm has a better performance compared with the DCT and K-SVD dictionaries.展开更多
Through sample plot survey and statistic analysis,this paper adopts ecological method to study the characteristics of plant diversity of forest vegetation in Luofu Mountain,Guangdong.The results show that there is a g...Through sample plot survey and statistic analysis,this paper adopts ecological method to study the characteristics of plant diversity of forest vegetation in Luofu Mountain,Guangdong.The results show that there is a great plant diversity of forest vegetation in Luofu Mountain owing to the ascendancy of aqueous and thermal condition in subtropical zone.The total number of species in 4 500 m2 sample plot(s)are 170 with 3 870 individual plants in total;Dahl species richness index(D)is 44.932;Simpson diversity index(L,D)is 0.022,0.022;Simpson(1982)diversity index(D)is 3.806;Pielou evenness index(E)is 0.984 and Hulbert evenness index(E)is 0.815;Shannon-wiener diversity index(information index H')is 4.188;Asymmetry index(r)is 0.185.These indexes show that a better habitat will bring about plant diversity of forest vegetation,and the diversity of zonal vegetation shows that the higher latitude is,the less species of vegetation can be found.Besides,vertical change of plant diversity of forest vegetation in Luofu Mountain is obvious.Its species richness index and plant diversity index show that monsoon evergreen broad-leaved forest is the tallest,mountain evergreen broad-leaved forest follows as the second and conifer-broad-leaved mixed forest is the shortest.The Wilson β-diversity index,which is obtained by comparison between forest vegetation below 300 m and forest vegetation between 600-900 m,is 0.621.Calculated from comparison between forest vegetation in 600-1 100 m and forest vegetation in 900-1 100 m,the Wilson β-diversity index is 0.727;by comparing forest vegetation below 300 m with forest vegetation in 900-1 100 m,the Wilson β-diversity index is 1.877.This shows that the plant diversity of forest vegetation is affected by the change in gradient of elevation.展开更多
In this contribution, I identify possible biotic elements of reptiles of China using biotic element analysis. I test whether the vicariance model could significantly shape reptilian current distribution patterns. My r...In this contribution, I identify possible biotic elements of reptiles of China using biotic element analysis. I test whether the vicariance model could significantly shape reptilian current distribution patterns. My results show that dispersal is prevailing for reptiles in China. There are four major biotic elements in reptilian distribution, which are East Xizang, Yunnan- Guizhou Plateau, Taiwan and Hainan, respectively. The test of distributional areas is significantly more clustered than expected by chance, while in another test that closely related species are homogeneously distributed across biotic elements cannot be rejected. Therefore I argued that vicariance might be one of the key processes in patterning reptilian distribution in China. In addition, I develop an improved biotic element analysis in biogeographic studies, by performing biotic element analysis in an iterative man- ner in order to diagnose more geographically restricted elements until no noise components found. The importance of antecedent selection of distributional data for the subsequent analysis is also discussed. Besides, my study indicates that biodiversity hotspots are not fully overlapped with areas of endemism for reptilians in East Asia展开更多
文摘The distributed passive measurement is an important technology for networkbehavior research. To achieve a consistent measurement, the same packets should be sampled atdistributed measurement points. And in order to estimate the character of traffic statistics, thetraffic sample should be random in statistics. A distributed samplingmask measurement model isintroduced to tackle the difficulty of measuring the full trace of high-speed networks. The keypoint of the model is to choose some bits that are suitable to be sampling mask. In the paper, thebit entropy and bit flow entropy of IP packet headers in CERNET backbone are analyzed, and we findthat the 16 bits of identification field in IP packet header are fit to the matching field ofsampling mask. Measurement traffic also can be used to analyze the statistical character ofmeasurement sample and the randomicity of the model. At the same time the experiment resultsindicate that the model has a good sampling performance.
文摘Subtree analysis and three area satements (TASS) procedure are used to deal with the area relationship in historical biogeography. On the basis of the taxon cladogram, the procedure could identify and eliminate the paralogy node and determine the informative subtree. The area relationships are generally illustrated in several subtrees and the consensus tree. The distribution pattern of the genus Caragana comprising about 72 species and occurring in 13 areas, was analyzed by using subtree method and TASS procedure in this study. The results showed seven subtrees representing the area relationships of section and series of the genus, and the consensus tree provided the 13 area relationships. These results are congruent with our former result using component analysis for Caragana.
基金Under the auspices of ‘One-Three-Five’ Strategic Planning Principles of Northeast Institute of Geography and Agroecology,Chinese Academy of Sciences(No.IGA-135-08)Research Foundation for Talents of Northeast Institute of Geography and Agroecology,Chinese Academy of Sciences(No.Y6H1211001)+1 种基金National Natural Science Foundation(No.41701372)Jilin Provincial Natural Science Fund Subject(No.20180101318JC)
文摘There is an increasing concern for potentially hazardous metals pollution, which can threaten crops production and human health. In this study, the spatial distribution and environmental risks of eight heavy metals in surface soil samples collected from the paddy fields in Yongshuyu irrigation area, Northeast China were investigated. The mean concentrations of Pb, Cr, Cu, Ni, Zn, Cd, Hg and As were 34.6 ± 4.67, 82.8 ± 9.51, 17.3 ± 4.09, 21.2 ± 12.0, 88.6 ± 17.9, 0.18 ± 0.15, 0.22 ± 0.07 and 8.77 ± 2.47 mg/kg, respectively, which were slightly higher than their corresponding background values of Jilin Province, indicating enrichment of these metals in the paddy soils, especially for Ni, Cd and Hg. The spatial distribution of heavy metals was closely correlated with local anthropogenic activities, such as agricultural production, mining and transportation. The hot-spot areas of As and Cd were mainly concentrated in the up-midstream where were associated with agricultural activities. Cr and Cu showed similar spatial distributions with hot-spot areas distributed the whole irrigation area uniformly. Ni was mainly distributed in the downstream where Ni quarries concentrated, while the spatial distribution patterns of Hg was mainly located in the upstream and downstream where the soil was significantly influenced by irrigation and coal mining emission. The spatial distributions of Pb and Zn were mainly concentrated along the highway side. The pollution levels of Yongshuyu irrigation area were estimated through index of geo-accumulation(Igeo), Nemerow integrated pollution index(NIPI) and potential ecological risk index(PERI). The results showed that Cd and Hg were the main pollutants in the study area. Health risk assessment results indicated that children were in higher non-carcinogenic and carcinogenic risks than adults with the carcinogenic metal of As. Ingestion was the main exposure pathway to non-carcinogenic and carcinogenic risk for both adults and children. Principal component analysis(PCA) indicated that Cr and Cu were mainly from parent materials, while Cd and As were mainly affected by agricultural activities. Pb and Zn were controlled by traffic activities, and the accumulations of Ni and Hg were associated with mining activities. This study would be valuable for preventing heavy metals inputs and safety in rice production of the Songhua river basin.
基金Supported by the National Natural Science Foundation of China (No.60434020, 60374020)International Cooperation Item of Henan (No.0446650006)Henan Outstanding Youth Science Fund (No.0312001900).
文摘This letter explores the distributed multisensor dynamic system, which has uniform sampling velocity and asynchronous sampling data for different sensors, and puts forward a new gradation fusion algorithm of multisensor dynamic system. As the total forecasted increment value between the two adjacent moments is the forecasted estimate value of the corresponding state increment in the fusion center, the new algorithm models the state and the forecasted estimate value of every moment. Kalman filter and all measurements arriving sequentially in the fusion period are employed to update the evaluation of target state step by step, on the condition that the system has obtained the target state evaluation that is based on the overall information in the previous fusion period. Accordingly, in the present period, the fusion evaluation of the target state at each sampling point on the basis of the overall information can be obtained. This letter elaborates the form of this new algorithm. Computer simulation demonstrates that this new algorithm owns greater precision in estimating target state than the present asynchronous fusion algorithm calibrated in time does.
基金supported by the Innovation Project of Graduate Students of Jiangsu Province, China under Grants No. CXZZ12_0466, No. CXZZ11_0390the National Natural Science Foundation of China under Grants No. 61071091, No. 61271240, No. 61201160, No. 61172118+2 种基金the Natural Science Foundation of the Higher Education Institutions of Jiangsu Province, China under Grant No. 12KJB510019the Science and Technology Research Program of Hubei Provincial Department of Education under Grants No. D20121408, No. D20121402the Program for Research Innovation of Nanjing Institute of Technology Project under Grant No. CKJ20110006
文摘Video reconstruction quality largely depends on the ability of employed sparse domain to adequately represent the underlying video in Distributed Compressed Video Sensing (DCVS). In this paper, we propose a novel dynamic global-Principal Component Analysis (PCA) sparse representation algorithm for video based on the sparse-land model and nonlocal similarity. First, grouping by matching is realized at the decoder from key frames that are previously recovered. Second, we apply PCA to each group (sub-dataset) to compute the principle components from which the sub-dictionary is constructed. Finally, the non-key frames are reconstructed from random measurement data using a Compressed Sensing (CS) reconstruction algorithm with sparse regularization. Experimental results show that our algorithm has a better performance compared with the DCT and K-SVD dictionaries.
文摘Through sample plot survey and statistic analysis,this paper adopts ecological method to study the characteristics of plant diversity of forest vegetation in Luofu Mountain,Guangdong.The results show that there is a great plant diversity of forest vegetation in Luofu Mountain owing to the ascendancy of aqueous and thermal condition in subtropical zone.The total number of species in 4 500 m2 sample plot(s)are 170 with 3 870 individual plants in total;Dahl species richness index(D)is 44.932;Simpson diversity index(L,D)is 0.022,0.022;Simpson(1982)diversity index(D)is 3.806;Pielou evenness index(E)is 0.984 and Hulbert evenness index(E)is 0.815;Shannon-wiener diversity index(information index H')is 4.188;Asymmetry index(r)is 0.185.These indexes show that a better habitat will bring about plant diversity of forest vegetation,and the diversity of zonal vegetation shows that the higher latitude is,the less species of vegetation can be found.Besides,vertical change of plant diversity of forest vegetation in Luofu Mountain is obvious.Its species richness index and plant diversity index show that monsoon evergreen broad-leaved forest is the tallest,mountain evergreen broad-leaved forest follows as the second and conifer-broad-leaved mixed forest is the shortest.The Wilson β-diversity index,which is obtained by comparison between forest vegetation below 300 m and forest vegetation between 600-900 m,is 0.621.Calculated from comparison between forest vegetation in 600-1 100 m and forest vegetation in 900-1 100 m,the Wilson β-diversity index is 0.727;by comparing forest vegetation below 300 m with forest vegetation in 900-1 100 m,the Wilson β-diversity index is 1.877.This shows that the plant diversity of forest vegetation is affected by the change in gradient of elevation.
文摘In this contribution, I identify possible biotic elements of reptiles of China using biotic element analysis. I test whether the vicariance model could significantly shape reptilian current distribution patterns. My results show that dispersal is prevailing for reptiles in China. There are four major biotic elements in reptilian distribution, which are East Xizang, Yunnan- Guizhou Plateau, Taiwan and Hainan, respectively. The test of distributional areas is significantly more clustered than expected by chance, while in another test that closely related species are homogeneously distributed across biotic elements cannot be rejected. Therefore I argued that vicariance might be one of the key processes in patterning reptilian distribution in China. In addition, I develop an improved biotic element analysis in biogeographic studies, by performing biotic element analysis in an iterative man- ner in order to diagnose more geographically restricted elements until no noise components found. The importance of antecedent selection of distributional data for the subsequent analysis is also discussed. Besides, my study indicates that biodiversity hotspots are not fully overlapped with areas of endemism for reptilians in East Asia
