According to the definitions of molecular connectivity and hyper-Wiener index, a novel set of hyper-Wiener indexes （Dn, ^mDn） were defined and named as condensed extended hyper-Wiener index, the potential usefulness...According to the definitions of molecular connectivity and hyper-Wiener index, a novel set of hyper-Wiener indexes （Dn, ^mDn） were defined and named as condensed extended hyper-Wiener index, the potential usefulness of which in QSAR/QSPR is evaluated by its correlation with a number of C3-C8 alkanes as well as by a favorable comparison with models based on molecular connectivity index and overall Wiener index.展开更多
Determinations of fracture network connections would help the investigators remove those ＂meaningless＂ no-flow-passing fractures, providing an updated and more effective fracture network that could considerably impr...Determinations of fracture network connections would help the investigators remove those ＂meaningless＂ no-flow-passing fractures, providing an updated and more effective fracture network that could considerably improve the computation efficiency in the pertinent numerical simulations of fluid flow and solute transport. The effective algorithms with higher computational efficiency are needed to accomplish this task in large-scale fractured rock masses. A new approach using R tree indexing was proposed for determining fracture connection in 3D stochastically distributed fracture network. By com- paring with the traditional exhaustion algorithm, it was observed that from the simulation results, this approach was much more effective; and the more the fractures were investigated, the more obvious the advantages of the approach were. Furthermore, it was indicated that the runtime used for creating the R tree indexing has a major part in the total of the runtime used for calculating Minimum Bounding Rectangles （MBRs）, creating the R tree indexing, precisely finding out fracture intersections, and identifying flow paths, which are four important steps to determine fracture connections. This proposed approach for the determination of fracture connections in three-dimensional fractured rocks are expected to provide efficient preprocessing and critical database for practically accomplishing numerical computation of fluid flow and solute transport in large-scale fractured rock masses.展开更多
The use of econometric methods to analyze the relationship between our country steel price index and the international iron ore freight rate,time series stationarity test,cointegration test,Granger test of causality a...The use of econometric methods to analyze the relationship between our country steel price index and the international iron ore freight rate,time series stationarity test,cointegration test,Granger test of causality and model parameter estimation tools use,find that there is Granger causality between our country steel price index and the international iron ore freight rate,China' s steel price fluctuations to some extent affect the international iron ore freight.展开更多
To categorize the nations to reflect the development status, to date, there are many conceptual frameworks. The Human Development index (HDI) that is published by the United Nations Development Programme is widely acc...To categorize the nations to reflect the development status, to date, there are many conceptual frameworks. The Human Development index (HDI) that is published by the United Nations Development Programme is widely accepted and practiced by many people such as academicians, politicians, and donor organizations. However, though the development of HDI has gone through many revisions since its formulation in 1990, even the current version of the index formulation published in 2016 needs research to better understand and to gap-fill the knowledge base that can enhance the index formulation to facilitate the direction of attention such as release of funds. Therefore, in this paper, based on principal component analysis and K-means clustering algorithm, the data that reflect the measures of life expectancy index (LEI), education index (EI), and income index (II) are analyzed to categorize and to rank the member states of the UN using R statistical software package, an open source extensible programming language for statistical computing and graphics. The outcome of the study shows that the proportion of total eigen value (i.e., proportion of total variance) explained by PCA-1 (i.e., first principal component) accounts for more than 85% of the total variation. Moreover, the proportion of total eigen value explained by PCA-1 increases with time (i.e., yearly) though the amount of increase with time is not significant. However, the proportions of total eigen value explained by PCA-2 and PCA-3 decrease with time. Therefore, the loss of information in choosing PCA-1 to represent the chosen explanatory variables (i.e., LEI, EI, and II) may diminish with time if the trend of increasing pattern of proportion of total eigen value explained by PCA-1 with time continues in the future as well. On the other hand, the correlation between EI and PCA-1 increases with time although the magnitude of increase is not that significant. This same trend is observed in II as well. However, in contrast to these observations, the correlation between PCA-1 and LEI decreases with time. These findings imply that the contributions of EI and II to PCA-1 increase with time, but the contribution of LEI to PCA-1 decreases with time. On top of these, as per Hopkins statistic, the clusterability of the information conveyed by PCA-1 alone is far better than the clusterability of the information conveyed by PCA scores (i.e., PCA-1, PCA-2, and PCA-3) and the explanatory variables. Therefore, choosing PCA-1 to represent the chosen explanatory variables is becoming more concrete.展开更多
With the decrease of global temperature, glacial epoch came over the earth and global climate fluctuated over a great range since the beginning of Quaternary. Paleoclimotologists of various countries have focussed att...With the decrease of global temperature, glacial epoch came over the earth and global climate fluctuated over a great range since the beginning of Quaternary. Paleoclimotologists of various countries have focussed attention to the periodic characteristics and dynamics of climatic fluctuation in the past many years (Berger, 1977; Imbrie and Hays, 1984; Ding Zhongli et al., 1990; Yu Zhiwei et al., 1992; Liu Youmei et al., 1996). Although some of the workers have paid their attention to the nonlinear characteristics of the global Quaternary environmental evolution (Nicolis and Nicolis, 1984; Lu Houyuan et al., 1993), it is worth while to do this kind of work in some special areas in the world, for example the Qinghai\|Tibet Plateau.\; Using R/S analysis, the authors calculated the Hurst indexes H of some geochemical proxies, including organic carbon, FeO, Fe\-2O\-3 and FeO/ Fe\-2O\-3, from the Tianshuihai Lake core in West Kunlun Mountain of the Qinghai\|Tibet Plateau. The proxies satisfy the Hurst law with H\-\{org.carbon\}=0.735, H\-\{Fe\-2O\-3\}=0.757, H\-\{FeO\}=0.848 and H\-\{FeO/Fe\-2O\-3\}=0.646. All the indexes are greater than 0.5, meaning that from 240 to 15 ka B.P., there were some long\|run dependencies\|persistence in the climatic and environmental evolution around the Tianshuihai Lake area. This is in accordance with the climate there from 240 to 15 ka B.P. (Yu Suhua et al., 1996). The paleo\|climate and paleo\|environment evolution around the Tianshuihai Lake area is of persistence as well as of fluctuation and is a combination of these two components. There are some differences between the four Hurst indexes, which probably resulted from the different intensities of persistence of the four proxies, organic carbon, FeO, Fe\-2O\-3 and FeO/ Fe\-2O\-3, or from the change of drainage system around the Tianshuihai Lake area from openness to closeness(Li Bingyuan et al., 1991; Sun Honglie, 1996; Shi Yafeng et al., 1998).\; The Qinghai\|Tibet plateau was the starter and sensor of the climatic and environmental variation of the surrounding areas (Yao Tandong et al., 1991; Feng Song et al., 1998) and some other scientists even regarded it as the driver and amplifier of global climatic variations (Pan Baotian and Li Jijun, 1996). The persistence in which the climate and environment around the Tianshuihai Lake area evolved from 240 to 15 ka B.P. is probably a function of the continuous uplift of the plateau in the same period of time.展开更多
In order to study social inequalities, indices can be used to summarize the multiple dimensions of the socioeconomic status. As a part of the Equit’Area Project, a public health program focused on social and environm...In order to study social inequalities, indices can be used to summarize the multiple dimensions of the socioeconomic status. As a part of the Equit’Area Project, a public health program focused on social and environmental health inequalities;a statistical procedure to create (neighborhood) socioeconomic indices was developed. This procedure uses successive principal components analyses to select variables and create the index. In order to simplify the application of the procedure for non-specialists, the R package SesIndexCreatoR was created. It allows the creation of the index with all the possible options of the procedure, the classification of the resulting index in categories using several classical methods, the visualization of the results, and the generation of automatic reports.展开更多
文摘According to the definitions of molecular connectivity and hyper-Wiener index, a novel set of hyper-Wiener indexes （Dn, ^mDn） were defined and named as condensed extended hyper-Wiener index, the potential usefulness of which in QSAR/QSPR is evaluated by its correlation with a number of C3-C8 alkanes as well as by a favorable comparison with models based on molecular connectivity index and overall Wiener index.
基金Supported by the Major State Basic Research Development Program of China （973 Program） （2010CB428804） the National Science Foundation ot China （40672172） and the Major Science and Technology Program for Water Pollution Control and Treatment（2009ZX07212-003）
文摘Determinations of fracture network connections would help the investigators remove those ＂meaningless＂ no-flow-passing fractures, providing an updated and more effective fracture network that could considerably improve the computation efficiency in the pertinent numerical simulations of fluid flow and solute transport. The effective algorithms with higher computational efficiency are needed to accomplish this task in large-scale fractured rock masses. A new approach using R tree indexing was proposed for determining fracture connection in 3D stochastically distributed fracture network. By com- paring with the traditional exhaustion algorithm, it was observed that from the simulation results, this approach was much more effective; and the more the fractures were investigated, the more obvious the advantages of the approach were. Furthermore, it was indicated that the runtime used for creating the R tree indexing has a major part in the total of the runtime used for calculating Minimum Bounding Rectangles （MBRs）, creating the R tree indexing, precisely finding out fracture intersections, and identifying flow paths, which are four important steps to determine fracture connections. This proposed approach for the determination of fracture connections in three-dimensional fractured rocks are expected to provide efficient preprocessing and critical database for practically accomplishing numerical computation of fluid flow and solute transport in large-scale fractured rock masses.
文摘The use of econometric methods to analyze the relationship between our country steel price index and the international iron ore freight rate,time series stationarity test,cointegration test,Granger test of causality and model parameter estimation tools use,find that there is Granger causality between our country steel price index and the international iron ore freight rate,China' s steel price fluctuations to some extent affect the international iron ore freight.
文摘To categorize the nations to reflect the development status, to date, there are many conceptual frameworks. The Human Development index (HDI) that is published by the United Nations Development Programme is widely accepted and practiced by many people such as academicians, politicians, and donor organizations. However, though the development of HDI has gone through many revisions since its formulation in 1990, even the current version of the index formulation published in 2016 needs research to better understand and to gap-fill the knowledge base that can enhance the index formulation to facilitate the direction of attention such as release of funds. Therefore, in this paper, based on principal component analysis and K-means clustering algorithm, the data that reflect the measures of life expectancy index (LEI), education index (EI), and income index (II) are analyzed to categorize and to rank the member states of the UN using R statistical software package, an open source extensible programming language for statistical computing and graphics. The outcome of the study shows that the proportion of total eigen value (i.e., proportion of total variance) explained by PCA-1 (i.e., first principal component) accounts for more than 85% of the total variation. Moreover, the proportion of total eigen value explained by PCA-1 increases with time (i.e., yearly) though the amount of increase with time is not significant. However, the proportions of total eigen value explained by PCA-2 and PCA-3 decrease with time. Therefore, the loss of information in choosing PCA-1 to represent the chosen explanatory variables (i.e., LEI, EI, and II) may diminish with time if the trend of increasing pattern of proportion of total eigen value explained by PCA-1 with time continues in the future as well. On the other hand, the correlation between EI and PCA-1 increases with time although the magnitude of increase is not that significant. This same trend is observed in II as well. However, in contrast to these observations, the correlation between PCA-1 and LEI decreases with time. These findings imply that the contributions of EI and II to PCA-1 increase with time, but the contribution of LEI to PCA-1 decreases with time. On top of these, as per Hopkins statistic, the clusterability of the information conveyed by PCA-1 alone is far better than the clusterability of the information conveyed by PCA scores (i.e., PCA-1, PCA-2, and PCA-3) and the explanatory variables. Therefore, choosing PCA-1 to represent the chosen explanatory variables is becoming more concrete.
文摘With the decrease of global temperature, glacial epoch came over the earth and global climate fluctuated over a great range since the beginning of Quaternary. Paleoclimotologists of various countries have focussed attention to the periodic characteristics and dynamics of climatic fluctuation in the past many years (Berger, 1977; Imbrie and Hays, 1984; Ding Zhongli et al., 1990; Yu Zhiwei et al., 1992; Liu Youmei et al., 1996). Although some of the workers have paid their attention to the nonlinear characteristics of the global Quaternary environmental evolution (Nicolis and Nicolis, 1984; Lu Houyuan et al., 1993), it is worth while to do this kind of work in some special areas in the world, for example the Qinghai\|Tibet Plateau.\; Using R/S analysis, the authors calculated the Hurst indexes H of some geochemical proxies, including organic carbon, FeO, Fe\-2O\-3 and FeO/ Fe\-2O\-3, from the Tianshuihai Lake core in West Kunlun Mountain of the Qinghai\|Tibet Plateau. The proxies satisfy the Hurst law with H\-\{org.carbon\}=0.735, H\-\{Fe\-2O\-3\}=0.757, H\-\{FeO\}=0.848 and H\-\{FeO/Fe\-2O\-3\}=0.646. All the indexes are greater than 0.5, meaning that from 240 to 15 ka B.P., there were some long\|run dependencies\|persistence in the climatic and environmental evolution around the Tianshuihai Lake area. This is in accordance with the climate there from 240 to 15 ka B.P. (Yu Suhua et al., 1996). The paleo\|climate and paleo\|environment evolution around the Tianshuihai Lake area is of persistence as well as of fluctuation and is a combination of these two components. There are some differences between the four Hurst indexes, which probably resulted from the different intensities of persistence of the four proxies, organic carbon, FeO, Fe\-2O\-3 and FeO/ Fe\-2O\-3, or from the change of drainage system around the Tianshuihai Lake area from openness to closeness(Li Bingyuan et al., 1991; Sun Honglie, 1996; Shi Yafeng et al., 1998).\; The Qinghai\|Tibet plateau was the starter and sensor of the climatic and environmental variation of the surrounding areas (Yao Tandong et al., 1991; Feng Song et al., 1998) and some other scientists even regarded it as the driver and amplifier of global climatic variations (Pan Baotian and Li Jijun, 1996). The persistence in which the climate and environment around the Tianshuihai Lake area evolved from 240 to 15 ka B.P. is probably a function of the continuous uplift of the plateau in the same period of time.
文摘In order to study social inequalities, indices can be used to summarize the multiple dimensions of the socioeconomic status. As a part of the Equit’Area Project, a public health program focused on social and environmental health inequalities;a statistical procedure to create (neighborhood) socioeconomic indices was developed. This procedure uses successive principal components analyses to select variables and create the index. In order to simplify the application of the procedure for non-specialists, the R package SesIndexCreatoR was created. It allows the creation of the index with all the possible options of the procedure, the classification of the resulting index in categories using several classical methods, the visualization of the results, and the generation of automatic reports.
