针对设备到设备(device to device, D2D)直连技术复用蜂窝网络资源导致用户间干扰的问题,提出了一种基于K-means与Gale-Shapley稳定匹配算法的D2D通信干扰管理资源分配方案。通过分析信号与干扰加噪声比公式,采用K-means聚类算法进行用...针对设备到设备(device to device, D2D)直连技术复用蜂窝网络资源导致用户间干扰的问题,提出了一种基于K-means与Gale-Shapley稳定匹配算法的D2D通信干扰管理资源分配方案。通过分析信号与干扰加噪声比公式,采用K-means聚类算法进行用户分组,降低用户间干扰,实现多对一资源复用;为提高通信系统容量且保证用户的公平性,采用Gale-Shapley稳定匹配算法在用户分组基础上实现信道资源共享。仿真结果表明,与基于贪婪的图着色资源分配算法相比,本文算法在保证系统容量基本稳定的情况下,系统干扰降低了10%~30%。展开更多
Arctic changes influence not only temperature and precipitation in the midlatitudes but also contribute to severe convection.This study investigates an extreme gale event that occurred on 30 April 2021 in East China a...Arctic changes influence not only temperature and precipitation in the midlatitudes but also contribute to severe convection.This study investigates an extreme gale event that occurred on 30 April 2021 in East China and was forced by an Arctic potential vorticity(PV)anomaly intrusion.Temperature advection steered by storms contributed to the equatorward propagation of Arctic high PV,forming the Northeast China cold vortex(NCCV).At the upper levels,a PV southward intrusion guided the combination of the polar jet and the subtropical jet,providing strong vertical wind shear and downward momentum transportation to the event.The PV anomaly cooled the upper troposphere and the northern part of East China,whereas the lower levels over southern East China were dominated by local warm air,thus establishing strong instability and baroclinicity.In addition,the entrainment of Arctic dry air strengthened the surface pressure gradient by evaporation cooling.Capturing the above mechanism has the potential to improve convective weather forecasts under climate change.This study suggests that the more frequent NCCV-induced gale events in recent years are partly due to high-latitude waviness and storm activities,and this hypothesis needs to be investigated using more cases.展开更多
Based on the conventional high-and low-altitude and surface observation data,the weather analysis and diagnosis methods were applied to analyze the cold wave process of Ulanqab in January 2016 from the aspects of weat...Based on the conventional high-and low-altitude and surface observation data,the weather analysis and diagnosis methods were applied to analyze the cold wave process of Ulanqab in January 2016 from the aspects of weather reality,circulation background,weather causes,and forecast test.The results show that strong cold air accumulated gradually near Lake Baikal and Central Siberia,affecting the city in a northwest path.During the cold wave process,the transverse trough moved southwards slowly at 500 hPa,and the ground cold high pressure was strong and stable.The cold air continued to move southwards,resulting in the strong cold wave and gale weather with a large impact range and long duration.The high-altitude jet at 300 hPa strengthened the cold wave pile,which was conducive to the outbreak of the cold wave.The intensity and location changes of the 500 hPa positive vorticity center,850 hPa cold advection region and 24-h ground pressure variation well showed the intensity of the cold wave process and the variation of the affected region.The influence of strong cold advection,ground positive pressure variation,and strong vertical wind shear were the main reasons for a strong drop in temperature and gale weather in this process.The test results of prediction reveal that the forecast value of the maximum temperature were relatively lower than the actual value,while the forecast of the minimum temperature was more accurate.The three warning signals were issued timely and accurately.The circulation pattern predicted by numerical models was more accurate in the early stage of the process,but there was an error in the late stage,and the forecast system moved slower than the actual situation.展开更多
Based on the daily sea surface wind field prediction data of Japan Meteorological Agency(JMA) forecast model,National Centers for Environmental Prediction(NCEP GFS) model and U.S.Navy Operational Global Atmospheric Pr...Based on the daily sea surface wind field prediction data of Japan Meteorological Agency(JMA) forecast model,National Centers for Environmental Prediction(NCEP GFS) model and U.S.Navy Operational Global Atmospheric Prediction System(NOGAPS) model at 12:00 UTC from June 28 to August 10 in 2009,the bias-removed ensemble mean(BRE) was used to do the forecast test on the sea surface wind fields,and the root-mean-square error(RMSE) was used to test and evaluate the forecast results.The results showed that the BRE considerably reduced the RMSEs of 24 and 48 h sea surface wind field forecasts,and the forecast skill was superior to that of the single model forecast.The RMSE decreases in the south of central Bohai Sea and the middle of the Yellow Sea were the most obvious.In addition,the BRE forecast improved evidently the forecast skill of the gale process which occurred during July 13-14 and August 7 in 2009.The forecast accuracy of the wind speed and the gale location was also improved.展开更多
Based on semi - order fuzzy supermaringales andsubmartingales, the semi- order fuzzy supermartingaleand submartingale theory is developed. The main resultis to generalize the Doob decomposition and the Riesz de-compos...Based on semi - order fuzzy supermaringales andsubmartingales, the semi- order fuzzy supermartingaleand submartingale theory is developed. The main resultis to generalize the Doob decomposition and the Riesz de-composition theorems of standard martingale theory tosemi - order fuzzy supermaringales and submartingales.The structure of semi - order fuzzy supermaringales andsubmartingales and the conditions of that they has Doobdecomposition (resp. Riesz decomposition) are discussedin detail.展开更多
Based on the gale observation data in 5 observation stations in Jinzhou area from 1973 to 2007,the gale trend and the periodic change in Jinzhou area were analyzed by using the linear trend estimation method and the s...Based on the gale observation data in 5 observation stations in Jinzhou area from 1973 to 2007,the gale trend and the periodic change in Jinzhou area were analyzed by using the linear trend estimation method and the spectral analysis method. Meanwhile,the circulation situation characteristics and the spatial-temporal distribution characteristics of gale in four seasons were discussed by surveying generally the weather charts. The results showed that the gale in Jinzhou area presented the fluctuation decline trend and had 3.5,7.0 years periodic changes. The gale in spring is the most and in summer was the least. It was less in winter and autumn. Seen from the analysis on the circulation situation,the gale circulation situation in Jinzhou area was similar to in Liaoning. The circulation situation in spring was basically consistent with in autumn,winter. The main situations had 3 kinds:north high south low(west high east low) ,two high clipping low,south high north low(east high west low) . In summer,the regional gale weather was mainly caused by the meso-micro scale system.展开更多
The 21st century "Maritime Silk Road" strategy is a significant part of the belt and road initiatives of China. The cognition and investigation of ocean environment is essential and necessary in these regions which ...The 21st century "Maritime Silk Road" strategy is a significant part of the belt and road initiatives of China. The cognition and investigation of ocean environment is essential and necessary in these regions which will provide scientific reference for many fields such as navigation, ocean engineering, and disaster prevent and reduction. A high-resolution cross-calibrated multi-platform wind product is used to analyze gales over the Maritime Silk Road. The yearly mean speed and space distribution of gale, and the frequencies and trends of gale and extreme wind speed are analyzed. The results show that relatively high pools of gale are mainly located in the waters of the Arabian Sea, the Somali Sea, Indo-China Peninsula sea area, and Bay of Bengal in the summer. The gale frequency of the Somali Sea is more than 90%. Overall, the gale days increase year by year in the majority of the South China Sea and the northern Indian Ocean, especially in the autumn and the winter.展开更多
文摘针对设备到设备(device to device, D2D)直连技术复用蜂窝网络资源导致用户间干扰的问题,提出了一种基于K-means与Gale-Shapley稳定匹配算法的D2D通信干扰管理资源分配方案。通过分析信号与干扰加噪声比公式,采用K-means聚类算法进行用户分组,降低用户间干扰,实现多对一资源复用;为提高通信系统容量且保证用户的公平性,采用Gale-Shapley稳定匹配算法在用户分组基础上实现信道资源共享。仿真结果表明,与基于贪婪的图着色资源分配算法相比,本文算法在保证系统容量基本稳定的情况下,系统干扰降低了10%~30%。
基金supported by the China National Science Foundation (Grant No. 41705029)Anhui Joint Foundation (Grant No.2208085UQ11)+2 种基金China Meteorological Administration special grants on innovation and development (Grant No. CXFZ2023J017)China Meteorological Administration special grants on decision-making meteorological service (Grant No. JCZX2022005)support from the innovation team at Anhui Meteorological Bureau
文摘Arctic changes influence not only temperature and precipitation in the midlatitudes but also contribute to severe convection.This study investigates an extreme gale event that occurred on 30 April 2021 in East China and was forced by an Arctic potential vorticity(PV)anomaly intrusion.Temperature advection steered by storms contributed to the equatorward propagation of Arctic high PV,forming the Northeast China cold vortex(NCCV).At the upper levels,a PV southward intrusion guided the combination of the polar jet and the subtropical jet,providing strong vertical wind shear and downward momentum transportation to the event.The PV anomaly cooled the upper troposphere and the northern part of East China,whereas the lower levels over southern East China were dominated by local warm air,thus establishing strong instability and baroclinicity.In addition,the entrainment of Arctic dry air strengthened the surface pressure gradient by evaporation cooling.Capturing the above mechanism has the potential to improve convective weather forecasts under climate change.This study suggests that the more frequent NCCV-induced gale events in recent years are partly due to high-latitude waviness and storm activities,and this hypothesis needs to be investigated using more cases.
文摘Based on the conventional high-and low-altitude and surface observation data,the weather analysis and diagnosis methods were applied to analyze the cold wave process of Ulanqab in January 2016 from the aspects of weather reality,circulation background,weather causes,and forecast test.The results show that strong cold air accumulated gradually near Lake Baikal and Central Siberia,affecting the city in a northwest path.During the cold wave process,the transverse trough moved southwards slowly at 500 hPa,and the ground cold high pressure was strong and stable.The cold air continued to move southwards,resulting in the strong cold wave and gale weather with a large impact range and long duration.The high-altitude jet at 300 hPa strengthened the cold wave pile,which was conducive to the outbreak of the cold wave.The intensity and location changes of the 500 hPa positive vorticity center,850 hPa cold advection region and 24-h ground pressure variation well showed the intensity of the cold wave process and the variation of the affected region.The influence of strong cold advection,ground positive pressure variation,and strong vertical wind shear were the main reasons for a strong drop in temperature and gale weather in this process.The test results of prediction reveal that the forecast value of the maximum temperature were relatively lower than the actual value,while the forecast of the minimum temperature was more accurate.The three warning signals were issued timely and accurately.The circulation pattern predicted by numerical models was more accurate in the early stage of the process,but there was an error in the late stage,and the forecast system moved slower than the actual situation.
基金Supported by Chinese Meteorological Administration's Special Funds(Meteorology) for Scientific Research on Public Causes( GYHY200906007)Gale Forecast Item of the Shengli Oil Field Observatory (2008001)~~
文摘Based on the daily sea surface wind field prediction data of Japan Meteorological Agency(JMA) forecast model,National Centers for Environmental Prediction(NCEP GFS) model and U.S.Navy Operational Global Atmospheric Prediction System(NOGAPS) model at 12:00 UTC from June 28 to August 10 in 2009,the bias-removed ensemble mean(BRE) was used to do the forecast test on the sea surface wind fields,and the root-mean-square error(RMSE) was used to test and evaluate the forecast results.The results showed that the BRE considerably reduced the RMSEs of 24 and 48 h sea surface wind field forecasts,and the forecast skill was superior to that of the single model forecast.The RMSE decreases in the south of central Bohai Sea and the middle of the Yellow Sea were the most obvious.In addition,the BRE forecast improved evidently the forecast skill of the gale process which occurred during July 13-14 and August 7 in 2009.The forecast accuracy of the wind speed and the gale location was also improved.
文摘Based on semi - order fuzzy supermaringales andsubmartingales, the semi- order fuzzy supermartingaleand submartingale theory is developed. The main resultis to generalize the Doob decomposition and the Riesz de-composition theorems of standard martingale theory tosemi - order fuzzy supermaringales and submartingales.The structure of semi - order fuzzy supermaringales andsubmartingales and the conditions of that they has Doobdecomposition (resp. Riesz decomposition) are discussedin detail.
文摘Based on the gale observation data in 5 observation stations in Jinzhou area from 1973 to 2007,the gale trend and the periodic change in Jinzhou area were analyzed by using the linear trend estimation method and the spectral analysis method. Meanwhile,the circulation situation characteristics and the spatial-temporal distribution characteristics of gale in four seasons were discussed by surveying generally the weather charts. The results showed that the gale in Jinzhou area presented the fluctuation decline trend and had 3.5,7.0 years periodic changes. The gale in spring is the most and in summer was the least. It was less in winter and autumn. Seen from the analysis on the circulation situation,the gale circulation situation in Jinzhou area was similar to in Liaoning. The circulation situation in spring was basically consistent with in autumn,winter. The main situations had 3 kinds:north high south low(west high east low) ,two high clipping low,south high north low(east high west low) . In summer,the regional gale weather was mainly caused by the meso-micro scale system.
基金The National Natural Science Foundation of China under contract Nos 61501433 and Grant 412760
文摘The 21st century "Maritime Silk Road" strategy is a significant part of the belt and road initiatives of China. The cognition and investigation of ocean environment is essential and necessary in these regions which will provide scientific reference for many fields such as navigation, ocean engineering, and disaster prevent and reduction. A high-resolution cross-calibrated multi-platform wind product is used to analyze gales over the Maritime Silk Road. The yearly mean speed and space distribution of gale, and the frequencies and trends of gale and extreme wind speed are analyzed. The results show that relatively high pools of gale are mainly located in the waters of the Arabian Sea, the Somali Sea, Indo-China Peninsula sea area, and Bay of Bengal in the summer. The gale frequency of the Somali Sea is more than 90%. Overall, the gale days increase year by year in the majority of the South China Sea and the northern Indian Ocean, especially in the autumn and the winter.