针对目前Turbo码分量编码器参数识别算法容错性不好、计算量大的缺点,该文提出一种基于校验方程符合度的新算法。首先,根据码元约束长度较小的特点,构建出编码器生成多项式数据库,然后通过遍历多项式数据库,计算出每种多项式所对应的平...针对目前Turbo码分量编码器参数识别算法容错性不好、计算量大的缺点,该文提出一种基于校验方程符合度的新算法。首先,根据码元约束长度较小的特点,构建出编码器生成多项式数据库,然后通过遍历多项式数据库,计算出每种多项式所对应的平均校验方程符合度值,其最大值所对应的索引号即为多项式库中的正确多项式索引号,从而完成编码多项式的识别。该算法仅仅遍历有限的多项式数据库,其计算量较小,只与截获的数据量有关;算法采用的数据为软判决信息,故其容错性能较好。仿真结果表明:在信噪比为0 d B条件下,仅需要截获10码块,交织长度为100的码元数据量,参数的识别率就能达到90%以上。展开更多
The State Transition Equation (STE) based method to automatically generate the parallel CRC circuits for any generator polynomial or required amount of parallelism is presented. The parallel CRC circuit so generate...The State Transition Equation (STE) based method to automatically generate the parallel CRC circuits for any generator polynomial or required amount of parallelism is presented. The parallel CRC circuit so generated is partially optimized before being fed to synthesis tools and works properly in our LAN transceiv-er. Compared with the cascading method, the proposed method gives better timing results and significantly re-duces the synthesis time, in particular.展开更多
Coal bed methane is unconventional raw natural gas stored in coal seam with considerable reserves in China.In recent years,as the coal bed methane production,the safety and the use of resources have been paid more att...Coal bed methane is unconventional raw natural gas stored in coal seam with considerable reserves in China.In recent years,as the coal bed methane production,the safety and the use of resources have been paid more attentions.Evaluating coal bed methane content is an urgent problem.A BET adsorption isotherm equation is used to process the experimental data.The various parameters of BET equation under different temperatures are obtained;a theoretical gas content correction factor is proposed,and an evaluation method of actual coal bed methane is established.展开更多
The Preston＇s method is considered as one of the most commonly employed methods to measure the wall shear stress. However, it is only possible to determine the wall shear stress from measured pressure differences of ...The Preston＇s method is considered as one of the most commonly employed methods to measure the wall shear stress. However, it is only possible to determine the wall shear stress from measured pressure differences of the Preston tube and undisturbed static pressure, combined with calibration curves, which depend on the Preston tube diameter, fluid density, and viscosity. Since its invention, no significant advancement in theory has been made, and calibration curves proposed by Preston, Patel and Bechert are still in use. In the present study, a need to measure surface shear stress over a circular cylinder prompted us to develop our original Preston tube system. The developed system has been calibrated by measuring the wall shear stress in the fully developed turbulent flow regime in a circular pipe. The present results generally confirm the previously reported calibration curves. A slight modification of the coefficients in the calibration equation shows further improvement.展开更多
In this paper,a multiscale problem arising in material science is considered.The problem involves a random coefficient which is assumed to be a perturbation of a deterministic coefficient,in a sense made precisely in ...In this paper,a multiscale problem arising in material science is considered.The problem involves a random coefficient which is assumed to be a perturbation of a deterministic coefficient,in a sense made precisely in the body of the text.The homogenized limit is then computed by using a perturbation approach.This computation requires repeatedly solving a corrector-like equation for various configurations of the material.For this purpose,the reduced basis approach is employed and adapted to the specific context.The authors perform numerical tests that demonstrate the efficiency of the approach.展开更多
文摘针对目前Turbo码分量编码器参数识别算法容错性不好、计算量大的缺点,该文提出一种基于校验方程符合度的新算法。首先,根据码元约束长度较小的特点,构建出编码器生成多项式数据库,然后通过遍历多项式数据库,计算出每种多项式所对应的平均校验方程符合度值,其最大值所对应的索引号即为多项式库中的正确多项式索引号,从而完成编码多项式的识别。该算法仅仅遍历有限的多项式数据库,其计算量较小,只与截获的数据量有关;算法采用的数据为软判决信息,故其容错性能较好。仿真结果表明:在信噪比为0 d B条件下,仅需要截获10码块,交织长度为100的码元数据量,参数的识别率就能达到90%以上。
文摘The State Transition Equation (STE) based method to automatically generate the parallel CRC circuits for any generator polynomial or required amount of parallelism is presented. The parallel CRC circuit so generated is partially optimized before being fed to synthesis tools and works properly in our LAN transceiv-er. Compared with the cascading method, the proposed method gives better timing results and significantly re-duces the synthesis time, in particular.
文摘Coal bed methane is unconventional raw natural gas stored in coal seam with considerable reserves in China.In recent years,as the coal bed methane production,the safety and the use of resources have been paid more attentions.Evaluating coal bed methane content is an urgent problem.A BET adsorption isotherm equation is used to process the experimental data.The various parameters of BET equation under different temperatures are obtained;a theoretical gas content correction factor is proposed,and an evaluation method of actual coal bed methane is established.
文摘The Preston＇s method is considered as one of the most commonly employed methods to measure the wall shear stress. However, it is only possible to determine the wall shear stress from measured pressure differences of the Preston tube and undisturbed static pressure, combined with calibration curves, which depend on the Preston tube diameter, fluid density, and viscosity. Since its invention, no significant advancement in theory has been made, and calibration curves proposed by Preston, Patel and Bechert are still in use. In the present study, a need to measure surface shear stress over a circular cylinder prompted us to develop our original Preston tube system. The developed system has been calibrated by measuring the wall shear stress in the fully developed turbulent flow regime in a circular pipe. The present results generally confirm the previously reported calibration curves. A slight modification of the coefficients in the calibration equation shows further improvement.
基金Project supported by EOARD(European Office of Aerospace Research and Development) (No.FA865510-C-4002)
文摘In this paper,a multiscale problem arising in material science is considered.The problem involves a random coefficient which is assumed to be a perturbation of a deterministic coefficient,in a sense made precisely in the body of the text.The homogenized limit is then computed by using a perturbation approach.This computation requires repeatedly solving a corrector-like equation for various configurations of the material.For this purpose,the reduced basis approach is employed and adapted to the specific context.The authors perform numerical tests that demonstrate the efficiency of the approach.
