为研究联合图像专家组2000(Jo in t Photograph ic Expert G roup 2000,JPEG 2000)图像压缩方法在核医学中的应用,将无病变和有病变核医学静态图像用JPEG 2000软件压缩。对无损压缩图像,测量其压缩比。对有损压缩图像,由医生阅片,根据...为研究联合图像专家组2000(Jo in t Photograph ic Expert G roup 2000,JPEG 2000)图像压缩方法在核医学中的应用,将无病变和有病变核医学静态图像用JPEG 2000软件压缩。对无损压缩图像,测量其压缩比。对有损压缩图像,由医生阅片,根据其结论作接收器操作特性(R ece iver operating characteristic,ROC)分析,获得各种图像压缩比的ROC曲线下的面积(A rea under curve,AUC),以其大小评价图像诊断质量;并将原始图像组AUC与各有损压缩图像组的AUC作配对t检验。实验发现,无损压缩的图像压缩比为(1.34±0.05)∶1。而有损压缩比越大,AUC越小。原始图像与压缩图像比较,压缩比为10∶1时没有显著性差异,压缩比更大时则有显著性差异。实验结果表明,无损压缩方法压缩比低,实用意义不大。有损压缩比不大于10∶1时,核医学静态图像的诊断质量得以保留。对核医学中的其它图像形式,可根据的图像性质,特别是固有统计噪声的大小,适当增减压缩比。展开更多
This study investigates calendar anomalies： day-of-the-week effect and seasonal effect in the Value-at-Risk （VaR） analysis of stock returns for AAPL during the period of 1995 through 2015. The statistical propertie...This study investigates calendar anomalies： day-of-the-week effect and seasonal effect in the Value-at-Risk （VaR） analysis of stock returns for AAPL during the period of 1995 through 2015. The statistical properties are examined and a comprehensive set of diagnostic checks are made on the two decades of AAPL daily stock returns. Combing the Extreme Value Approach together with a statistical analysis, it is learnt that the lowest VaR occurs on Fridays and Mondays typically. Moreover, high Q4 and Q3 VaR are observed during the test period. These results are valuable for anyone who needs evaluation and forecasts of the risk situation in AAPL. Moreover, this methodology, which is applicable to any other stocks or portfolios, is more realistic and comprehensive than the standard normal distribution based VaR model that is commonly used.展开更多
The purpose of this paper is to improve allocation of the number of bits without skipping the frame by accurately estimating the target bits in H. 264/AVC rate control. The scheme ImPoses an enhancement method of the ...The purpose of this paper is to improve allocation of the number of bits without skipping the frame by accurately estimating the target bits in H. 264/AVC rate control. The scheme ImPoses an enhancement method of the target frame rate based on H. 264/AVC bit allocation. The enhancement uses a frame complexion estimation to improve the existing Mean Absolute Difference （MAD） complexity measurement. Bit allocation to each frame is not just computed by target frame rote but also adjusted by a combined frame complexity measure. Using the statistical characteristic, the scheme obtains change of occurrence bit about QP to apply the bit amount by QP from the video characteristic and apply it in the estimated bit amount of the current frame. Simulation results show that the proposed rate eontrol scheme achieves time saving of mine than 99% over existing rate control algorithm. Nevertheless, Peak Signal-to-Noise Ration （PSNR） and bit rate were almost the same as the performances.展开更多
A mathematical model of management of a social insurance fund with exponential insurance reimburse and financing determined social programs is represented and analyzed; A probability density function and fund＇s funct...A mathematical model of management of a social insurance fund with exponential insurance reimburse and financing determined social programs is represented and analyzed; A probability density function and fund＇s functioning probabilistic characteristics are obtained, that makes it possible to determine the sufficiency of fund capital at all levels of its management. With the help of conclusion it is possible for particular period of time determine in insurance fund change of cash flow movement speed, on what basis in determined from state tax revenues assigns acceptance necessity and capacity.展开更多
文摘为研究联合图像专家组2000(Jo in t Photograph ic Expert G roup 2000,JPEG 2000)图像压缩方法在核医学中的应用,将无病变和有病变核医学静态图像用JPEG 2000软件压缩。对无损压缩图像,测量其压缩比。对有损压缩图像,由医生阅片,根据其结论作接收器操作特性(R ece iver operating characteristic,ROC)分析,获得各种图像压缩比的ROC曲线下的面积(A rea under curve,AUC),以其大小评价图像诊断质量;并将原始图像组AUC与各有损压缩图像组的AUC作配对t检验。实验发现,无损压缩的图像压缩比为(1.34±0.05)∶1。而有损压缩比越大,AUC越小。原始图像与压缩图像比较,压缩比为10∶1时没有显著性差异,压缩比更大时则有显著性差异。实验结果表明,无损压缩方法压缩比低,实用意义不大。有损压缩比不大于10∶1时,核医学静态图像的诊断质量得以保留。对核医学中的其它图像形式,可根据的图像性质,特别是固有统计噪声的大小,适当增减压缩比。
文摘This study investigates calendar anomalies： day-of-the-week effect and seasonal effect in the Value-at-Risk （VaR） analysis of stock returns for AAPL during the period of 1995 through 2015. The statistical properties are examined and a comprehensive set of diagnostic checks are made on the two decades of AAPL daily stock returns. Combing the Extreme Value Approach together with a statistical analysis, it is learnt that the lowest VaR occurs on Fridays and Mondays typically. Moreover, high Q4 and Q3 VaR are observed during the test period. These results are valuable for anyone who needs evaluation and forecasts of the risk situation in AAPL. Moreover, this methodology, which is applicable to any other stocks or portfolios, is more realistic and comprehensive than the standard normal distribution based VaR model that is commonly used.
文摘The purpose of this paper is to improve allocation of the number of bits without skipping the frame by accurately estimating the target bits in H. 264/AVC rate control. The scheme ImPoses an enhancement method of the target frame rate based on H. 264/AVC bit allocation. The enhancement uses a frame complexion estimation to improve the existing Mean Absolute Difference （MAD） complexity measurement. Bit allocation to each frame is not just computed by target frame rote but also adjusted by a combined frame complexity measure. Using the statistical characteristic, the scheme obtains change of occurrence bit about QP to apply the bit amount by QP from the video characteristic and apply it in the estimated bit amount of the current frame. Simulation results show that the proposed rate eontrol scheme achieves time saving of mine than 99% over existing rate control algorithm. Nevertheless, Peak Signal-to-Noise Ration （PSNR） and bit rate were almost the same as the performances.
文摘A mathematical model of management of a social insurance fund with exponential insurance reimburse and financing determined social programs is represented and analyzed; A probability density function and fund＇s functioning probabilistic characteristics are obtained, that makes it possible to determine the sufficiency of fund capital at all levels of its management. With the help of conclusion it is possible for particular period of time determine in insurance fund change of cash flow movement speed, on what basis in determined from state tax revenues assigns acceptance necessity and capacity.
