In order to solve the problem of poor interpretability of support vector re- gression (SVR) applied in quantitative structure-property relationship (QSPR), a com- plete set of explanatory system for SVR was establ...In order to solve the problem of poor interpretability of support vector re- gression (SVR) applied in quantitative structure-property relationship (QSPR), a com- plete set of explanatory system for SVR was established based on F-test, The nov- el explanatory system includes significance tests of model and single-descriptor im- portance, single-descriptor effect and sensitivity analysis, and significance tests of interaction between two descriptors, etc. The results of example indicated that the explanatory results of the new system were consistent well with those of stepwise linear regression model and quadratic polynomial stepwise regression model. The explanatory SVR model will play an important role in regression analysis such as QSPR.展开更多
[Objective] The aim was to reveal the effects of different land use types on soil composition. [Method] GPRS,soil organic carbon content and soil texture in 3 depths (0-10,10-20,20-50 cm) of 5 main kind of selected la...[Objective] The aim was to reveal the effects of different land use types on soil composition. [Method] GPRS,soil organic carbon content and soil texture in 3 depths (0-10,10-20,20-50 cm) of 5 main kind of selected land use type were examined in Hainan. [Result] The results showed that GRSP and SOC content of four artificial land use types decreased compared with the natural secondary forest land,the GRSP content of all samples ranged from 0.53-4.80 mg/g,accounting for 7.9%-23.4% of the SOC,which means that GRSP was one important component of SOC pool in soil. The ratio of GRSP to SOC was significantly different among land use types but the depths. GRSP and SOC exhibited obvious vertical distribution pattern. GRSP was significantly positively related to SOC and sand content but negatively related to silt and clay content. [Conclusion] The sand content determined the GRSP content significantly and loam was better matrix for GRSP accumulation than clay.展开更多
Six tea plantations with different soil-forming parent materials, the same tea variety and tea age and similar landforms and management were selected to conduct a systematic study on the relationship between soil prop...Six tea plantations with different soil-forming parent materials, the same tea variety and tea age and similar landforms and management were selected to conduct a systematic study on the relationship between soil properties and tea quality. The results showed that the quality of tea grown on the soils derived from granites, arenaceous shales, argillaceous sandstones, was superior; those on the soils derived from limestones,dolomites, Quaternary red clays, were inferior. Further study showed that sandy soils were beneficial to improving amino acid content of tea, and clayey soils made it decrease; high content of bases might decrease the contents of tea polypenols, caffeine, water extracts, but promote the content of amino acids; available phosphorous was significantly positively correlated with water extracts, but significantly negatively correlated with carbine; slowly available potassium was positively correlated with amino acid content. Soil parent materials should be regarded as an important factor in evaluating the adaptability of tea to soils.展开更多
The Doppler-limited absorption spectra of ^14N and ^15N atoms were measured around 800 nm using concentration modulation spectroscopy to study their isotope shifts. The nitrogen atoms were generated by discharging mol...The Doppler-limited absorption spectra of ^14N and ^15N atoms were measured around 800 nm using concentration modulation spectroscopy to study their isotope shifts. The nitrogen atoms were generated by discharging molecular nitrogen buffered with helium in a homemade discharge tube. The isotope shifts of four multiplets (3s^4PJ→3p^4D^oJ, 3s^4PJ→3p^4P^oJ, 3s^2DJ→5s^2P^oJ, and 3p^2P^oJ→5s^2D^oJ) were measured and their J-dependent specific mass shifts were observed and discussed.展开更多
The nature and origin of a fundamental quantum QSPR (QQSPR) equation are discussed. In principle, as any molecular structure can be associated to quantum mechanical density functions (DF), a molecular set can be r...The nature and origin of a fundamental quantum QSPR (QQSPR) equation are discussed. In principle, as any molecular structure can be associated to quantum mechanical density functions (DF), a molecular set can be reconstructed as a quantum multimolecular polyhedron (QMP), whose vertices are formed by each molecular DF. According to QQSPR theory, complicated kinds of molecular properties, like biological activity or toxicity, of molecular sets can be calculated via the quantum expectation value of an approximate Hermitian operator, which can be evaluated with the geometrical information contained in the attached QMP via quantum similarity matrices. Practical ways of solving the QQSPR problem from the point of view of QMP geometrical structure are provided. Such a development results into a powerful algorithm, which can be implemented within molecular design as an alternative to the current classical QSPR procedures.展开更多
The study aims to focus upon the association between the auditors and companies by indicating how this association affects the quality of audit and auditor independence in a developing country (the case of Bahrain)....The study aims to focus upon the association between the auditors and companies by indicating how this association affects the quality of audit and auditor independence in a developing country (the case of Bahrain). To achieve these objectives, a questionnaire was developed and distributed to respondents from audit firms in Bahrain. Descriptive statistics were used to analyse the influence of auditor-client association upon quality of audit and auditor independence and how audit quality and auditor independence are improved was also explored in the study. The results show that all the questions (1-8) in the questionnaire impair both audit quality and auditor independence with the means ranging from 3.6000 to 4.0364 with an average mean of 3.7212. According to the measurement scale, any item with a mean of 3.50 or more is acceptable, and since all the influences are above 3.50, they are all acceptable. Regarding how auditor-client relationship (or long tenured auditor) would improve both quality of audit and auditor independence, the results show that all the questions (9-17) would improve both audit quality and auditor independence with the means ranging from 3.6364 to 4.0727 with an average of 3.8646, which are acceptable. These results confirm statistically that there is a significant relationship between the auditor long-term tenure and audit quality and auditor independence, so the null hypothesis (H0) is rejected and the alternative hypothesis is accepted. Simple regression analysis is employed to test the hypothesis of the study and its significance. The results show that (H0) hypothesis is not significant. Therefore, the alternative hypothesis (H1) is significant at p 〈 0.005, which means that there are differences in viewpoints among respondents and the p-value obtained is 0.044 which is less than the significant value of p 〈 0.05. These results confirm the hypothesis that a significant relationship exists between the auditor long-term tenure and quality of audit and auditor independence.展开更多
The thermal decomposition temperature is one of the most important parameters to evaluate fire hazard of organic peroxide. A quantitative structure-property relationship model was proposed for estimating the thermal d...The thermal decomposition temperature is one of the most important parameters to evaluate fire hazard of organic peroxide. A quantitative structure-property relationship model was proposed for estimating the thermal decomposition temperatures of organic peroxides. The entire set of 38 organic peroxides was at random divided into a training set for model development and a prediction set for external model validation. The novel local molecular descriptors of AT1, AT2, AT3, AT4, AT5, AT6 and global molecular descriptor of ATC have been proposed in order to character organic peroxides’ molecular structures. An accurate quantitative structure-property relationship (QSPR) equation is developed for the thermal decomposition temperatures of organic peroxides. The statistical results showed that the QSPR model was obtained using the multiple linear regression (MLR) method with correlation coefficient (R), standard deviation (S), leave-one-out validation correlation coefficient (RCV) values of 0.9795, 6.5676 ℃ and 0.9328, respectively. The average absolute relative deviation (AARD) is only 3.86% for the experimental values. Model test by internal leave-one-out cross validation and external validation and molecular descriptor interpretation were discussed. Comparison with literature results demonstrated that novel local and global descriptors were useful molecular descriptors for predicting the thermal decomposition temperatures of organic peroxides.展开更多
The study was conducted in a plastic tunnel in which the heat storage system was installed in the stone accumulator. The system consists of a suction pipe warm air fan and perforated pipes placed in the stone's accum...The study was conducted in a plastic tunnel in which the heat storage system was installed in the stone accumulator. The system consists of a suction pipe warm air fan and perforated pipes placed in the stone's accumulator. The accumulator used a bed of stone (porphyry-type stones of dimension in the range 37 mm to 65 ram). In the accumulator, there are four sections with dimensions of 1.7 m × 11 m, each of which contains a perforated pipe for hot air distribution within the battery, and separate conduits for supplying air to the interior of the tunnel. The paper presents the results of analysis related to performance (as a result of heat and mass transfer) in cycles of charging and discharging of the accumulator.展开更多
The quantitative structure-property relationship(QSPR) of anabolic androgenic steroids was studied on the half-wave reduction potential(E1/2) using quantum and physico-chemical molecular descriptors. The descriptors w...The quantitative structure-property relationship(QSPR) of anabolic androgenic steroids was studied on the half-wave reduction potential(E1/2) using quantum and physico-chemical molecular descriptors. The descriptors were calculated by semi-empirical calculations. Models were established using partial least square(PLS) regression and back-propagation artificial neural network(BP-ANN). The QSPR results indicate that the descriptors of these derivatives have significant relationship with half-wave reduction potential. The stability and prediction ability of these models were validated using leave-one-out cross-validation and external test set.展开更多
A filed experiment was conducted continuously for three days,and the velocity variation was measured using coda wave interferometry.The measurement error is estimated to be around 10-4,which coincides well with the th...A filed experiment was conducted continuously for three days,and the velocity variation was measured using coda wave interferometry.The measurement error is estimated to be around 10-4,which coincides well with the theoretical error.The velocity variation during this period is up to 10-3.The relationship between velocity variation and changes in air temperature,barometric pressure and solid earth tide was analyzed with linear least square fitting.The velocity has no dependence on air temperature,but displayed change of the order of 10-6~10-7 when the barometer or earth tide changed one Pa.展开更多
In this paper, a novel reconstruction technique based on level set method and algebraic reconstruction technique is proposed for multiphase flow computed tomography (CT) system. The curvature-driven noise reduction me...In this paper, a novel reconstruction technique based on level set method and algebraic reconstruction technique is proposed for multiphase flow computed tomography (CT) system. The curvature-driven noise reduction method is inserted into the conventional iteration procedure of algebraic reconstruction technique to improve the image quality and convergence speed with limited projection data. By evolving the image as a set of iso-intensity contours after each updation, the sufficient number of iterations for acceptable results is reduced by 80%-90%, while the image quality is enhanced obviously. Quantitative evaluation of image quality is given by using both relative image error and correlation coefficient. The resultant images can be utilized to detect flow regimes for monitoring industrial multiphase flow. Laboratory results demonstrate the feasibility of the proposed method. Phantoms of four typical flow regimes can be reconstructed from few-view projection data efficiently, and the corresponding image errors and correlation coefficients are acceptable for the cases tested in this paper.展开更多
Service composition is a hot and active research area in service-oriented computing which has gained great momentum. An quality of service (QoS) oriented and tree-based approach was proposed to implement service compo...Service composition is a hot and active research area in service-oriented computing which has gained great momentum. An quality of service (QoS) oriented and tree-based approach was proposed to implement service composition efficiently. Firstly, service descriptions were transformed to mapping relations which denote the association between input and output concepts. Then, the service composition problems were resolved by building mapping relation tree dynamically based on the divide and conquer method, and all mapping relation trees were combined without redundant branch to obtain the composition scheme. Finally, the optimal composition scheme was chosen based on quality of service attributes including the preference of service request. Experiment results illustrate that this method can improve the composition efficiency and reduce the searching time by increasing the number of services in repository.展开更多
This paper investigates empirically the link between the inflow of Diasporas remittances and the environment of accounting/auditing in 10 African countries. The result using Spearman's rank correlation indicates the ...This paper investigates empirically the link between the inflow of Diasporas remittances and the environment of accounting/auditing in 10 African countries. The result using Spearman's rank correlation indicates the existence of a positive relationship (correlation coefficient rs is 0.36), but the strength of the relationship is weak (significant level of 0.05). The quality of accounting and auditing as represented by their environment is a stimulus that could enhance the inflow of Diasporas remittances. The study therefore recommends that African countries should strategically and proactively refocus attention on developing accounting/auditing environment in order to attract reasonable volume of remittances.展开更多
The mass-dependent symmetry energy coefficients asym(A) has been extracted by analysing the heavy nuclear mass differences reducing the uncertainties as far as possible in our previous work. Taking advantage of the ...The mass-dependent symmetry energy coefficients asym(A) has been extracted by analysing the heavy nuclear mass differences reducing the uncertainties as far as possible in our previous work. Taking advantage of the obtained symmetry energy coefficient asym(A) and the density profiles obtained by switching off the Coulomb interaction in ^208Pb, we calculated the slope parameter L0.11 of the symmetry energy at the density of 0.11 fm^-3. The calculated L0.11 ranges from 40.5 MeV to 60.3 MeV. The slope parameter L0.11 of the symmetry energy at the density of 0.11 fm^-3 is also calculated directly with Skyrme interactions for nuclear matter and is found to have a fine linear relation with the neutron skin thickness of ^208spb, which is the difference of the neutron and proton rms radii of the nucleus. With the linear relation the neutron skin thickness ARnp of ^208spb is predicted to be 0.15-0.21 fm.展开更多
With increasing numbers and types of nature reserves(NRs),objective evaluation and comparison of the effects of different nature NRs on conservation efforts are of great importance for protecting species diversity,ens...With increasing numbers and types of nature reserves(NRs),objective evaluation and comparison of the effects of different nature NRs on conservation efforts are of great importance for protecting species diversity,ensuring reasonable national economic input,and adjusting government management schemes.Developing a method for the combined assessment of flagship or umbrella species and ecosystem quality will improve the evaluation of NRs.However,it is also important to establish a new framework for rapid evaluation of ecosystem quality,supported by the advantages of scientific,economic,and regular principles.Here,we proposed a new framework that incorporates the novel concept of ideal references into evaluation systems,which will facilitate the comparison of results from different periods and regions.Furthermore,from the perspective of making the framework as objective,rapid,and economical as possible,we recommended some key ecological indicators,such as net primary productivity,soil organic matter,plant diversity,for use in the new evaluation framework.The new framework,referred to as“ideal reference and key indicators”(IRKI),can sufficiently meet the requirements for the rapid evaluation of ecosystem quality both regionally and nationally.Furthermore,IRKI can identify the restoration potential and restoration periods of NRs,thus facilitating the rational distribution of resources and enhancing the protective effect.There are many types of NRs in China,and it is necessary to partially alter the assessment methods or parameters for different types of NRs.Overall,IRKI provides a simple,clear,and comparable framework that will strongly enhance the conservation of protected areas(PAs)and facilitate the standardization of management practices.展开更多
A generalized scheme for the construction of coherent states in the context of position-dependent effective mass systems has been presented. This formalism is based on the ladder operators and associated algebra of th...A generalized scheme for the construction of coherent states in the context of position-dependent effective mass systems has been presented. This formalism is based on the ladder operators and associated algebra of the system which are obtained using the concepts of supersymmetric quantum mechanics and the property of shape invariance. In order to exemplify the general results and to analyze the properties of the coherent states, several examples have been considered.展开更多
基金Supported by Industrialization Cultivation Projects in Colleges and Universities of Hunan Province(13CY030)Natural Science Foundation of Hunan Province(12JJ6026)Colleges and Universities Open Innovation Platform Fund of Hunan Province(14K053,15K066)~~
文摘In order to solve the problem of poor interpretability of support vector re- gression (SVR) applied in quantitative structure-property relationship (QSPR), a com- plete set of explanatory system for SVR was established based on F-test, The nov- el explanatory system includes significance tests of model and single-descriptor im- portance, single-descriptor effect and sensitivity analysis, and significance tests of interaction between two descriptors, etc. The results of example indicated that the explanatory results of the new system were consistent well with those of stepwise linear regression model and quadratic polynomial stepwise regression model. The explanatory SVR model will play an important role in regression analysis such as QSPR.
基金Supported by National Natural Science Foundation of China(40761024)~~
文摘[Objective] The aim was to reveal the effects of different land use types on soil composition. [Method] GPRS,soil organic carbon content and soil texture in 3 depths (0-10,10-20,20-50 cm) of 5 main kind of selected land use type were examined in Hainan. [Result] The results showed that GRSP and SOC content of four artificial land use types decreased compared with the natural secondary forest land,the GRSP content of all samples ranged from 0.53-4.80 mg/g,accounting for 7.9%-23.4% of the SOC,which means that GRSP was one important component of SOC pool in soil. The ratio of GRSP to SOC was significantly different among land use types but the depths. GRSP and SOC exhibited obvious vertical distribution pattern. GRSP was significantly positively related to SOC and sand content but negatively related to silt and clay content. [Conclusion] The sand content determined the GRSP content significantly and loam was better matrix for GRSP accumulation than clay.
文摘Six tea plantations with different soil-forming parent materials, the same tea variety and tea age and similar landforms and management were selected to conduct a systematic study on the relationship between soil properties and tea quality. The results showed that the quality of tea grown on the soils derived from granites, arenaceous shales, argillaceous sandstones, was superior; those on the soils derived from limestones,dolomites, Quaternary red clays, were inferior. Further study showed that sandy soils were beneficial to improving amino acid content of tea, and clayey soils made it decrease; high content of bases might decrease the contents of tea polypenols, caffeine, water extracts, but promote the content of amino acids; available phosphorous was significantly positively correlated with water extracts, but significantly negatively correlated with carbine; slowly available potassium was positively correlated with amino acid content. Soil parent materials should be regarded as an important factor in evaluating the adaptability of tea to soils.
文摘The Doppler-limited absorption spectra of ^14N and ^15N atoms were measured around 800 nm using concentration modulation spectroscopy to study their isotope shifts. The nitrogen atoms were generated by discharging molecular nitrogen buffered with helium in a homemade discharge tube. The isotope shifts of four multiplets (3s^4PJ→3p^4D^oJ, 3s^4PJ→3p^4P^oJ, 3s^2DJ→5s^2P^oJ, and 3p^2P^oJ→5s^2D^oJ) were measured and their J-dependent specific mass shifts were observed and discussed.
文摘The nature and origin of a fundamental quantum QSPR (QQSPR) equation are discussed. In principle, as any molecular structure can be associated to quantum mechanical density functions (DF), a molecular set can be reconstructed as a quantum multimolecular polyhedron (QMP), whose vertices are formed by each molecular DF. According to QQSPR theory, complicated kinds of molecular properties, like biological activity or toxicity, of molecular sets can be calculated via the quantum expectation value of an approximate Hermitian operator, which can be evaluated with the geometrical information contained in the attached QMP via quantum similarity matrices. Practical ways of solving the QQSPR problem from the point of view of QMP geometrical structure are provided. Such a development results into a powerful algorithm, which can be implemented within molecular design as an alternative to the current classical QSPR procedures.
文摘The study aims to focus upon the association between the auditors and companies by indicating how this association affects the quality of audit and auditor independence in a developing country (the case of Bahrain). To achieve these objectives, a questionnaire was developed and distributed to respondents from audit firms in Bahrain. Descriptive statistics were used to analyse the influence of auditor-client association upon quality of audit and auditor independence and how audit quality and auditor independence are improved was also explored in the study. The results show that all the questions (1-8) in the questionnaire impair both audit quality and auditor independence with the means ranging from 3.6000 to 4.0364 with an average mean of 3.7212. According to the measurement scale, any item with a mean of 3.50 or more is acceptable, and since all the influences are above 3.50, they are all acceptable. Regarding how auditor-client relationship (or long tenured auditor) would improve both quality of audit and auditor independence, the results show that all the questions (9-17) would improve both audit quality and auditor independence with the means ranging from 3.6364 to 4.0727 with an average of 3.8646, which are acceptable. These results confirm statistically that there is a significant relationship between the auditor long-term tenure and audit quality and auditor independence, so the null hypothesis (H0) is rejected and the alternative hypothesis is accepted. Simple regression analysis is employed to test the hypothesis of the study and its significance. The results show that (H0) hypothesis is not significant. Therefore, the alternative hypothesis (H1) is significant at p 〈 0.005, which means that there are differences in viewpoints among respondents and the p-value obtained is 0.044 which is less than the significant value of p 〈 0.05. These results confirm the hypothesis that a significant relationship exists between the auditor long-term tenure and quality of audit and auditor independence.
基金Project(2015SK20823) supported by Science and Technology Project of Hunan Province,ChinaProject(15A001) supported by Scientific Research Fund of Hunan Provincial Education Department,China+2 种基金Project(2017CL06) supported by Hunan Provincial Key Laboratory of Materials Protection for Electric Power and Transportation,ChinaProject(k1403029-11) supported by Science and Technology Project of Changsha City,ChinaProject(CX2015B372) supported by the Hunan Provincial Innovation Foundation for Postgraduate,China
文摘The thermal decomposition temperature is one of the most important parameters to evaluate fire hazard of organic peroxide. A quantitative structure-property relationship model was proposed for estimating the thermal decomposition temperatures of organic peroxides. The entire set of 38 organic peroxides was at random divided into a training set for model development and a prediction set for external model validation. The novel local molecular descriptors of AT1, AT2, AT3, AT4, AT5, AT6 and global molecular descriptor of ATC have been proposed in order to character organic peroxides’ molecular structures. An accurate quantitative structure-property relationship (QSPR) equation is developed for the thermal decomposition temperatures of organic peroxides. The statistical results showed that the QSPR model was obtained using the multiple linear regression (MLR) method with correlation coefficient (R), standard deviation (S), leave-one-out validation correlation coefficient (RCV) values of 0.9795, 6.5676 ℃ and 0.9328, respectively. The average absolute relative deviation (AARD) is only 3.86% for the experimental values. Model test by internal leave-one-out cross validation and external validation and molecular descriptor interpretation were discussed. Comparison with literature results demonstrated that novel local and global descriptors were useful molecular descriptors for predicting the thermal decomposition temperatures of organic peroxides.
文摘The study was conducted in a plastic tunnel in which the heat storage system was installed in the stone accumulator. The system consists of a suction pipe warm air fan and perforated pipes placed in the stone's accumulator. The accumulator used a bed of stone (porphyry-type stones of dimension in the range 37 mm to 65 ram). In the accumulator, there are four sections with dimensions of 1.7 m × 11 m, each of which contains a perforated pipe for hot air distribution within the battery, and separate conduits for supplying air to the interior of the tunnel. The paper presents the results of analysis related to performance (as a result of heat and mass transfer) in cycles of charging and discharging of the accumulator.
基金Project supported by the Postdoctoral Science Foundation of Central South University,ChinaProject(2015SK20823)supported by Science and Technology Project of Hunan Province,China+2 种基金Project(15A001)supported by Scientific Research Fund of Hunan Provincial Education Department,ChinaProject(CX2015B372)supported by Hunan Provincial Innovation Foundation for Postgraduate,ChinaProject supported by Innovation Experiment Program for University Students of Changsha University of Science and Technology,China
文摘The quantitative structure-property relationship(QSPR) of anabolic androgenic steroids was studied on the half-wave reduction potential(E1/2) using quantum and physico-chemical molecular descriptors. The descriptors were calculated by semi-empirical calculations. Models were established using partial least square(PLS) regression and back-propagation artificial neural network(BP-ANN). The QSPR results indicate that the descriptors of these derivatives have significant relationship with half-wave reduction potential. The stability and prediction ability of these models were validated using leave-one-out cross-validation and external test set.
基金sponsored by the Special R & D Project of China Earthquake Administration(200808002)the Special Project of Basic Scientific Research of the Institute of Geophysics,CEA(DQJB08B13)
文摘A filed experiment was conducted continuously for three days,and the velocity variation was measured using coda wave interferometry.The measurement error is estimated to be around 10-4,which coincides well with the theoretical error.The velocity variation during this period is up to 10-3.The relationship between velocity variation and changes in air temperature,barometric pressure and solid earth tide was analyzed with linear least square fitting.The velocity has no dependence on air temperature,but displayed change of the order of 10-6~10-7 when the barometer or earth tide changed one Pa.
基金Supported by National Natural Science Foundation of China (No.60820106002,No.60532020)Natural Science Foundation of Tianjin(No.11JCYBJC06900)
文摘In this paper, a novel reconstruction technique based on level set method and algebraic reconstruction technique is proposed for multiphase flow computed tomography (CT) system. The curvature-driven noise reduction method is inserted into the conventional iteration procedure of algebraic reconstruction technique to improve the image quality and convergence speed with limited projection data. By evolving the image as a set of iso-intensity contours after each updation, the sufficient number of iterations for acceptable results is reduced by 80%-90%, while the image quality is enhanced obviously. Quantitative evaluation of image quality is given by using both relative image error and correlation coefficient. The resultant images can be utilized to detect flow regimes for monitoring industrial multiphase flow. Laboratory results demonstrate the feasibility of the proposed method. Phantoms of four typical flow regimes can be reconstructed from few-view projection data efficiently, and the corresponding image errors and correlation coefficients are acceptable for the cases tested in this paper.
基金Project(2007AA01Z126) supported by the National High Technology Research and Development Program of China
文摘Service composition is a hot and active research area in service-oriented computing which has gained great momentum. An quality of service (QoS) oriented and tree-based approach was proposed to implement service composition efficiently. Firstly, service descriptions were transformed to mapping relations which denote the association between input and output concepts. Then, the service composition problems were resolved by building mapping relation tree dynamically based on the divide and conquer method, and all mapping relation trees were combined without redundant branch to obtain the composition scheme. Finally, the optimal composition scheme was chosen based on quality of service attributes including the preference of service request. Experiment results illustrate that this method can improve the composition efficiency and reduce the searching time by increasing the number of services in repository.
文摘This paper investigates empirically the link between the inflow of Diasporas remittances and the environment of accounting/auditing in 10 African countries. The result using Spearman's rank correlation indicates the existence of a positive relationship (correlation coefficient rs is 0.36), but the strength of the relationship is weak (significant level of 0.05). The quality of accounting and auditing as represented by their environment is a stimulus that could enhance the inflow of Diasporas remittances. The study therefore recommends that African countries should strategically and proactively refocus attention on developing accounting/auditing environment in order to attract reasonable volume of remittances.
基金supported by the National Natural Science Foundation of China(Grant Nos.11175219,10975190,11275271 and 11405223)the National Basic Research Program of China(Grant No.2013CB834405)+2 种基金the Knowledge Innovation Project of Chinese Academy of Sciences(Grant No.KJCX2-EW-N01)the Funds for Creative Research Groups of China(Grant No.11321064)the Youth Innovation Promotion Association of Chinese Academy of Sciences
文摘The mass-dependent symmetry energy coefficients asym(A) has been extracted by analysing the heavy nuclear mass differences reducing the uncertainties as far as possible in our previous work. Taking advantage of the obtained symmetry energy coefficient asym(A) and the density profiles obtained by switching off the Coulomb interaction in ^208Pb, we calculated the slope parameter L0.11 of the symmetry energy at the density of 0.11 fm^-3. The calculated L0.11 ranges from 40.5 MeV to 60.3 MeV. The slope parameter L0.11 of the symmetry energy at the density of 0.11 fm^-3 is also calculated directly with Skyrme interactions for nuclear matter and is found to have a fine linear relation with the neutron skin thickness of ^208spb, which is the difference of the neutron and proton rms radii of the nucleus. With the linear relation the neutron skin thickness ARnp of ^208spb is predicted to be 0.15-0.21 fm.
基金The Chinese Academy of Sciences Strategic Priority Research Program(XDA23080401)The National Natural Science Foundation of China(32171544,31988102).
文摘With increasing numbers and types of nature reserves(NRs),objective evaluation and comparison of the effects of different nature NRs on conservation efforts are of great importance for protecting species diversity,ensuring reasonable national economic input,and adjusting government management schemes.Developing a method for the combined assessment of flagship or umbrella species and ecosystem quality will improve the evaluation of NRs.However,it is also important to establish a new framework for rapid evaluation of ecosystem quality,supported by the advantages of scientific,economic,and regular principles.Here,we proposed a new framework that incorporates the novel concept of ideal references into evaluation systems,which will facilitate the comparison of results from different periods and regions.Furthermore,from the perspective of making the framework as objective,rapid,and economical as possible,we recommended some key ecological indicators,such as net primary productivity,soil organic matter,plant diversity,for use in the new evaluation framework.The new framework,referred to as“ideal reference and key indicators”(IRKI),can sufficiently meet the requirements for the rapid evaluation of ecosystem quality both regionally and nationally.Furthermore,IRKI can identify the restoration potential and restoration periods of NRs,thus facilitating the rational distribution of resources and enhancing the protective effect.There are many types of NRs in China,and it is necessary to partially alter the assessment methods or parameters for different types of NRs.Overall,IRKI provides a simple,clear,and comparable framework that will strongly enhance the conservation of protected areas(PAs)and facilitate the standardization of management practices.
文摘A generalized scheme for the construction of coherent states in the context of position-dependent effective mass systems has been presented. This formalism is based on the ladder operators and associated algebra of the system which are obtained using the concepts of supersymmetric quantum mechanics and the property of shape invariance. In order to exemplify the general results and to analyze the properties of the coherent states, several examples have been considered.