A modified multiple-component scattering power decomposition for analyzing polarimetric synthetic aperture radar(PolSAR)data is proposed.The modified decomposition involves two distinct steps.Firstly,ei⁃genvectors of ...A modified multiple-component scattering power decomposition for analyzing polarimetric synthetic aperture radar(PolSAR)data is proposed.The modified decomposition involves two distinct steps.Firstly,ei⁃genvectors of the coherency matrix are used to modify the scattering models.Secondly,the entropy and anisotro⁃py of targets are used to improve the volume scattering power.With the guarantee of high double-bounce scatter⁃ing power in the urban areas,the proposed algorithm effectively improves the volume scattering power of vegeta⁃tion areas.The efficacy of the modified multiple-component scattering power decomposition is validated using ac⁃tual AIRSAR PolSAR data.The scattering power obtained through decomposing the original coherency matrix and the coherency matrix after orientation angle compensation is compared with three algorithms.Results from the experiment demonstrate that the proposed decomposition yields more effective scattering power for different PolSAR data sets.展开更多
A stochastic model of conducting crack propagation is presented to provide a conceptual framework dedicated to the study of the formation of fractal structure of dielectric ageing patterns as a result of a competition...A stochastic model of conducting crack propagation is presented to provide a conceptual framework dedicated to the study of the formation of fractal structure of dielectric ageing patterns as a result of a competition between random fluctuation growth and applied electric strength enhanced deterministic growth. The necessary and sufficient conditions resulting in fractal behaviour in dielectric ageing are found.展开更多
Understanding the dynamic traffic and usage characteristics of data services in cellular networks is important for optimising network resources and improving user experience.Recent studies have illustrated traffic cha...Understanding the dynamic traffic and usage characteristics of data services in cellular networks is important for optimising network resources and improving user experience.Recent studies have illustrated traffic characteristics from specific perspectives,such as user behaviour,device type,and applications.In this paper,we present the results of our study from a different perspective,namely service providers,to reveal the traffic characteristics of cellular data networks.Our study is based on traffic data collected over a five-day period from a leading mobile operator's core network in China.We propose a Zipf-like model to characterise the distributions of the traffic volume,subscribers,and requests among service providers.Nine distinct diurnal traffic patterns of service providers are identified by formulating and solving a time series clustering problem.Our work differs from previous related works in that we perform measurements on a large quantity of data covering 2.2 billion traffic records,and we first explore the traffic patterns of thousands of service providers.Results of our study present mobile Internet participants with a better understanding of the traffic and usage characteristics of service providers,which play a critical role in the mobile Internet era.展开更多
In order to study the evolution laws during the development process of the coal face overburden rock mining-induced fissure,we studied the process of evolution of overburden rock mining-induced fissures and dynamicall...In order to study the evolution laws during the development process of the coal face overburden rock mining-induced fissure,we studied the process of evolution of overburden rock mining-induced fissures and dynamically quantitatively described its fractal laws,based on the high-precision microseismic monitoring method and the nonlinear Fractal Geometry Theory.The results show that:the overburden rock mining-induced fissure fractal dimension experiences two periodic change processes with the coal face advance,namely a Small→ Big→ Small process,which tends to be stable;the functional relationship between the extraction step distance and the overburden rock mining-induced fissure fractal dimension is a cubic curve.The results suggest that the fractal dimension reflects the evolution characteristics of the overburden rock mining-induced fissure,which can be used as an evaluation index of the stability of the overburden rock strata,and it provides theoretical guidance for stability analysis of the overburden rock strata,goaf roof control and the support movements in the mining face.展开更多
Objective: To investigate the methylation status of the PCDH8 (Protocadherin-8) gene in gastric cancer tissues and find out the relationship between methylation status of the PCDH8 and clinicopathological features in ...Objective: To investigate the methylation status of the PCDH8 (Protocadherin-8) gene in gastric cancer tissues and find out the relationship between methylation status of the PCDH8 and clinicopathological features in gastric cancer patients. Methods: We first investigated the methylation status of the PCDH8 (Protocadherin-8) gene in 65 gastric cancer and detected aberrant promoter methylation in gastric cancers; and then analyzed he relationship between methylation status of the PCDH8 and clinicopathological status with SPSS 13.0 software. Results: We first investigated the methylation status of the PCDH8 (Protocadherin-8) gene in 65 gastric cancer and detected aberrant promoter methylation in 36 of 65 (55.4%) gastric cancers. There was no significant difference in the distribution of patients with methylation or unmethylation of PCDH8 in terms of age, sex, tumor size, distant metastasis, or TNM stage. Methylation of PCDH8 was significantly correlated to negative pathological lymph node metastasis (P=0.038) and tumor differentiation (P=0.01). These two factors were proved to be of prognostic importance. Conclusion: Methylated PCDH8 seems to have a trend for worse prognosis in gastric cancer. However, a further large series of tumor samples and a longer follow-up period are required to elucidate its potential role.展开更多
Research on the permeability and pressure distribution characteristics of the roadway surrounding rock in the excavation damaged zone(EDZ) is beneficial for the development of gas control technology. In this study, an...Research on the permeability and pressure distribution characteristics of the roadway surrounding rock in the excavation damaged zone(EDZ) is beneficial for the development of gas control technology. In this study, analytical solutions of stress and strain of the roadway surrounding rock were obtained, in which the creep deformation and strain softening were considered. Using the MTS815 rock mechanics testing system and a gas permeability testing system, permeability tests were conducted in the complete stress-strain process, and the evolution characteristics of permeability and strain were studied over the whole loading process. Based on the analytical solutions of stress and strain and the governing equation of gas seepage flow, this paper proposes a hydro-mechanical(HM) model, which considers three different zones around the roadway. Then the gas flow process in the roadway surrounding rock in three different zones was simulated according to the engineering geological conditions, thus obtaining the permeability and pressure distribution characteristics of the roadway surrounding rock in three different zones. These results show that the surrounding rock around the roadway can be divided into four regions-the full flow zone(FFZ), flow-shielding zone(FSZ), transitive flow zone(TFZ), and in-situ rock flow zone(IRFZ). These results could provide theoretical guidance for the improvement of gas extraction and gas control technology.展开更多
The effects of mechanical activation in a planetary mill on the structural changes and microstructural characteristics of the components of ferruginous quartzite beneficiation railings generated by wet magnetic separa...The effects of mechanical activation in a planetary mill on the structural changes and microstructural characteristics of the components of ferruginous quartzite beneficiation railings generated by wet magnetic separation process were studied using X-ray and laser diffraction methods. The results revealed the relationship between variations in the mean particle size of activated powders and the milling time. The crystallite size, microstrain, lattice parameters and unit cell volumes were determined for different milling times in powder samples of quartz, hematite, dolomite, and magnetite from the beneficiation tailings. The main trends in the variation of the crystallite size of quartz, hematite, dolomite, and magnetite as a function mean particle size of powder samples were revealed. Changes in the particle shape as a function of the activation time was also investigated.展开更多
基金Supported by the National Natural Science Foundation of China(62376214)the Natural Science Basic Research Program of Shaanxi(2023-JC-YB-533)Foundation of Ministry of Education Key Lab.of Cognitive Radio and Information Processing(Guilin University of Electronic Technology)(CRKL200203)。
文摘A modified multiple-component scattering power decomposition for analyzing polarimetric synthetic aperture radar(PolSAR)data is proposed.The modified decomposition involves two distinct steps.Firstly,ei⁃genvectors of the coherency matrix are used to modify the scattering models.Secondly,the entropy and anisotro⁃py of targets are used to improve the volume scattering power.With the guarantee of high double-bounce scatter⁃ing power in the urban areas,the proposed algorithm effectively improves the volume scattering power of vegeta⁃tion areas.The efficacy of the modified multiple-component scattering power decomposition is validated using ac⁃tual AIRSAR PolSAR data.The scattering power obtained through decomposing the original coherency matrix and the coherency matrix after orientation angle compensation is compared with three algorithms.Results from the experiment demonstrate that the proposed decomposition yields more effective scattering power for different PolSAR data sets.
文摘A stochastic model of conducting crack propagation is presented to provide a conceptual framework dedicated to the study of the formation of fractal structure of dielectric ageing patterns as a result of a competition between random fluctuation growth and applied electric strength enhanced deterministic growth. The necessary and sufficient conditions resulting in fractal behaviour in dielectric ageing are found.
基金supported by the National Natural Science Foundation of China under Grant No.61072061the 111 Project of China under Grant No.B08004the Fundamental Research Funds for the Central Universities under Grant No.2013RC0114
文摘Understanding the dynamic traffic and usage characteristics of data services in cellular networks is important for optimising network resources and improving user experience.Recent studies have illustrated traffic characteristics from specific perspectives,such as user behaviour,device type,and applications.In this paper,we present the results of our study from a different perspective,namely service providers,to reveal the traffic characteristics of cellular data networks.Our study is based on traffic data collected over a five-day period from a leading mobile operator's core network in China.We propose a Zipf-like model to characterise the distributions of the traffic volume,subscribers,and requests among service providers.Nine distinct diurnal traffic patterns of service providers are identified by formulating and solving a time series clustering problem.Our work differs from previous related works in that we perform measurements on a large quantity of data covering 2.2 billion traffic records,and we first explore the traffic patterns of thousands of service providers.Results of our study present mobile Internet participants with a better understanding of the traffic and usage characteristics of service providers,which play a critical role in the mobile Internet era.
基金Financial support for this work,provided by the National Natural Science Foundation of China(No.51304154)the Natural Science Foundation Anhui Province(No.1408085MKL92)
文摘In order to study the evolution laws during the development process of the coal face overburden rock mining-induced fissure,we studied the process of evolution of overburden rock mining-induced fissures and dynamically quantitatively described its fractal laws,based on the high-precision microseismic monitoring method and the nonlinear Fractal Geometry Theory.The results show that:the overburden rock mining-induced fissure fractal dimension experiences two periodic change processes with the coal face advance,namely a Small→ Big→ Small process,which tends to be stable;the functional relationship between the extraction step distance and the overburden rock mining-induced fissure fractal dimension is a cubic curve.The results suggest that the fractal dimension reflects the evolution characteristics of the overburden rock mining-induced fissure,which can be used as an evaluation index of the stability of the overburden rock strata,and it provides theoretical guidance for stability analysis of the overburden rock strata,goaf roof control and the support movements in the mining face.
文摘Objective: To investigate the methylation status of the PCDH8 (Protocadherin-8) gene in gastric cancer tissues and find out the relationship between methylation status of the PCDH8 and clinicopathological features in gastric cancer patients. Methods: We first investigated the methylation status of the PCDH8 (Protocadherin-8) gene in 65 gastric cancer and detected aberrant promoter methylation in gastric cancers; and then analyzed he relationship between methylation status of the PCDH8 and clinicopathological status with SPSS 13.0 software. Results: We first investigated the methylation status of the PCDH8 (Protocadherin-8) gene in 65 gastric cancer and detected aberrant promoter methylation in 36 of 65 (55.4%) gastric cancers. There was no significant difference in the distribution of patients with methylation or unmethylation of PCDH8 in terms of age, sex, tumor size, distant metastasis, or TNM stage. Methylation of PCDH8 was significantly correlated to negative pathological lymph node metastasis (P=0.038) and tumor differentiation (P=0.01). These two factors were proved to be of prognostic importance. Conclusion: Methylated PCDH8 seems to have a trend for worse prognosis in gastric cancer. However, a further large series of tumor samples and a longer follow-up period are required to elucidate its potential role.
基金financially supported by the Natural Science Foundation of Jiangsu Province,China(No.BK20140189)the Postdoctoral Science Foundation of China(No.2014M550315)
文摘Research on the permeability and pressure distribution characteristics of the roadway surrounding rock in the excavation damaged zone(EDZ) is beneficial for the development of gas control technology. In this study, analytical solutions of stress and strain of the roadway surrounding rock were obtained, in which the creep deformation and strain softening were considered. Using the MTS815 rock mechanics testing system and a gas permeability testing system, permeability tests were conducted in the complete stress-strain process, and the evolution characteristics of permeability and strain were studied over the whole loading process. Based on the analytical solutions of stress and strain and the governing equation of gas seepage flow, this paper proposes a hydro-mechanical(HM) model, which considers three different zones around the roadway. Then the gas flow process in the roadway surrounding rock in three different zones was simulated according to the engineering geological conditions, thus obtaining the permeability and pressure distribution characteristics of the roadway surrounding rock in three different zones. These results show that the surrounding rock around the roadway can be divided into four regions-the full flow zone(FFZ), flow-shielding zone(FSZ), transitive flow zone(TFZ), and in-situ rock flow zone(IRFZ). These results could provide theoretical guidance for the improvement of gas extraction and gas control technology.
文摘The effects of mechanical activation in a planetary mill on the structural changes and microstructural characteristics of the components of ferruginous quartzite beneficiation railings generated by wet magnetic separation process were studied using X-ray and laser diffraction methods. The results revealed the relationship between variations in the mean particle size of activated powders and the milling time. The crystallite size, microstrain, lattice parameters and unit cell volumes were determined for different milling times in powder samples of quartz, hematite, dolomite, and magnetite from the beneficiation tailings. The main trends in the variation of the crystallite size of quartz, hematite, dolomite, and magnetite as a function mean particle size of powder samples were revealed. Changes in the particle shape as a function of the activation time was also investigated.
