TEC and Instrumental Bias Estimation of GAGAN Station Using Kalman Filter and SCORE Algorithm

The standalone Global Positioning System (GPS) does not meet the higher accuracy requirements needed for approach and landing phase of an aircraft. To meet the Category-I Precision Approach (CAT-I PA) requirements of civil aviation, satellite based augmentation system (SBAS) has been planned by various countries including USA, Europe, Japan and India. The Indian SBAS is named as GPS Aided Geo Augmented Navigation (GAGAN). The GAGAN network consists of several dual frequency GPS receivers located at various airports around the Indian subcontinent. The ionospheric delay, which is a function of the total electron content (TEC), is one of the main sources of error affecting GPS/SBAS accuracy. A dual frequency GPS receiver can be used to estimate the TEC. However, line-of-sight TEC derived from dual frequency GPS data is corrupted by the instrumental biases of the GPS receiver and satellites. The estimation of receiver instrumental bias is particularly important for obtaining accurate estimates of ionospheric delay. In this paper, two prominent techniques based on Kalman filter and Self-Calibration Of pseudo Range Error (SCORE) algorithm are used for estimation of instrumental biases. The estimated instrumental bias and TEC results for the GPS Aided Geo Augmented Navigation (GAGAN) station at Hyderabad (78.47°E, 17.45°N), India are presented.

基于倾向值匹配估计的工会工资溢价研究

笔者基于2010年中国综合社会调查数据,采用倾向值匹配的方法,通过干预组的平均干预效应估计、平衡性检验和敏感性分析对工会工资溢价进行实证研究。实证结果显示:工会会员和非工会会员之间的工资差距在没有进行倾向值匹配之前比较大,而在采用倾向值匹配估计后,工会会员和非工会会员的工资差距变得不明显。最终结论为工会身份这个干预变量对工资溢价的影响不明显,工资溢价主要是由工人的资源禀赋差异造成的。

非线性回归模型中的拟Fisher信息

给出拟Fisher信息达到其上界的充要条件,此条件为真得分函数是线性无偏的,即观测数据来自指数族分布,当拟Fisher信息太小时,提出了一种线性有偏拟得分方法,该方法能增加拟Fisher信息,从而改进了参数估计。

针刺联合耳穴贴压干预偏颇体质糖耐量减低的临床观察

目的:探讨针刺联合耳穴贴压干预偏颇体质糖耐量减低的临床效果。方法:选择2020年7月—2022年1月河源市中医院收治的60例偏颇体质糖耐量减低患者为研究对象,根据随机数表法分为两组,各30例。两组均维持原有降糖药物治疗,对照组按照中医四诊仪体质报告予以生活方式指导,干预组在对照组基础上予以针刺联合耳穴贴压治疗,两组均完成6个月治疗。比较两组疗效、中医症候积分、血糖水平、炎症因子水平。结果:两组均连续完成6个月治疗,干预组总有效率为93.33%,高于对照组的73.33%,差异有统计学意义(P<0.05)。治疗6个月后,两组体型肥胖、四肢倦怠、食后饱满、头身困重及纳呆呕恶评分及空腹血糖、餐后2 h血糖、C反应蛋白(CRP)、白细胞介素-6(IL-6)水平较治疗前降低,且干预组低于对照组,差异有统计学意义(P<0.05)。结论:针刺联合耳穴贴压干预偏颇体质糖耐量减低患者,能提高临床效果,降低中医症候积分、血糖及炎症因子水平。