This paper is concerned with the distributional properties of a median unbiased estimator of ARCH(0,1)coefficient.The exact distribution of the estimator can be easily derived,however its practical calculations are to...This paper is concerned with the distributional properties of a median unbiased estimator of ARCH(0,1)coefficient.The exact distribution of the estimator can be easily derived,however its practical calculations are too heavy to implement, even though the middle range of sample sizes.Since the estimator is shown to have asymptotic normality,asymptotic expansions for the distribution and the percentiles of the estimator are derived as the refinements.Accuracies of expansion formulas are evaluated numerically,and the results of which show that we can effectively use the expansion as a fine approximation of the distribution with rapid calculations.Derived expansion are applied to testing hypothesis of stationarity,and an implementation for a real data set is illustrated.展开更多
目的:探讨ARCH钛板联合单开门椎管扩大成形术(expansive single open door-laminoplasty,EOLP)治疗脊髓型颈椎病(cervical spondylotic myelopathy,CSM)的近期临床疗效。方法:2016年1月至2016年12月将ARCH钛板做内固定材料的EOLP应用于3...目的:探讨ARCH钛板联合单开门椎管扩大成形术(expansive single open door-laminoplasty,EOLP)治疗脊髓型颈椎病(cervical spondylotic myelopathy,CSM)的近期临床疗效。方法:2016年1月至2016年12月将ARCH钛板做内固定材料的EOLP应用于32例CSM患者的治疗中,男23例,女9例;年龄39～82岁,平均64.5岁;病程6～24个月,平均13.1个月。临床疗效评定采用日本骨科协会(JOA)评分法,评分内容包括上下肢运动功能、肢体感觉功能、膀胱功能。通过影像学资料测量术前和术后6个月最狭窄节段的椎管矢状径,计算其改善率以明确减压效果。结果:所有患者获得随访,时间6～20个月,平均12.2个月。32例患者的术前症状均有不同程度好转,JOA评分由术前的9.78±1.34提高至术后6个月的12.94±1.16,JOA改善率为(44.09±11.06)%(P<0.01)。椎管扩大明显,最狭窄处椎管矢状径由术前的(8.47±0.60)mm扩大至术后6个月的(12.51±0.78)mm,改善率为(48.27±11.81)%(P<0.01)。随访期间未见内固定物松动、移位、断裂及"再关门"现象。结论:ARCH钛板联合EOLP治疗CSM可明显减少出现"再关门"及其他相关术后并发症的可能,近期临床疗效满意。展开更多
文摘This paper is concerned with the distributional properties of a median unbiased estimator of ARCH(0,1)coefficient.The exact distribution of the estimator can be easily derived,however its practical calculations are too heavy to implement, even though the middle range of sample sizes.Since the estimator is shown to have asymptotic normality,asymptotic expansions for the distribution and the percentiles of the estimator are derived as the refinements.Accuracies of expansion formulas are evaluated numerically,and the results of which show that we can effectively use the expansion as a fine approximation of the distribution with rapid calculations.Derived expansion are applied to testing hypothesis of stationarity,and an implementation for a real data set is illustrated.
文摘目的:探讨ARCH钛板联合单开门椎管扩大成形术(expansive single open door-laminoplasty,EOLP)治疗脊髓型颈椎病(cervical spondylotic myelopathy,CSM)的近期临床疗效。方法:2016年1月至2016年12月将ARCH钛板做内固定材料的EOLP应用于32例CSM患者的治疗中,男23例,女9例;年龄39～82岁,平均64.5岁;病程6～24个月,平均13.1个月。临床疗效评定采用日本骨科协会(JOA)评分法,评分内容包括上下肢运动功能、肢体感觉功能、膀胱功能。通过影像学资料测量术前和术后6个月最狭窄节段的椎管矢状径,计算其改善率以明确减压效果。结果:所有患者获得随访,时间6～20个月,平均12.2个月。32例患者的术前症状均有不同程度好转,JOA评分由术前的9.78±1.34提高至术后6个月的12.94±1.16,JOA改善率为(44.09±11.06)%(P<0.01)。椎管扩大明显,最狭窄处椎管矢状径由术前的(8.47±0.60)mm扩大至术后6个月的(12.51±0.78)mm,改善率为(48.27±11.81)%(P<0.01)。随访期间未见内固定物松动、移位、断裂及"再关门"现象。结论:ARCH钛板联合EOLP治疗CSM可明显减少出现"再关门"及其他相关术后并发症的可能,近期临床疗效满意。
