针对室内无线局域网环境下接收信号强度(RSS,received signal strength)样本总体分布不一致而产生较大定位误差的问题,提出了一种基于偏度峰度检验的室内定位算法。利用偏度峰度检验法检验RSS样本是否来自正态总体,接受零假设的样本用...针对室内无线局域网环境下接收信号强度(RSS,received signal strength)样本总体分布不一致而产生较大定位误差的问题,提出了一种基于偏度峰度检验的室内定位算法。利用偏度峰度检验法检验RSS样本是否来自正态总体,接受零假设的样本用正态分布近似其总体分布,拒绝零假设的样本用核函数估计其概率密度。实验结果表明提出算法的定位精度比传统算法提高15%以上,而且在相同的定位精度下,能明显降低离线阶段的工作量。展开更多
目的观察不同通气方法对老年全麻俯卧位脊柱手术患者围术期呼吸功能的影响。方法选择拟在全麻俯卧位下行腰骶椎手术的老年患者60例,ASAⅠ或Ⅱ级,性别不限,年龄65∽75岁,体重50∽80 kg,体重指数≤25 kg/m2;采用随机法,将其分为3组,每组2...目的观察不同通气方法对老年全麻俯卧位脊柱手术患者围术期呼吸功能的影响。方法选择拟在全麻俯卧位下行腰骶椎手术的老年患者60例,ASAⅠ或Ⅱ级,性别不限,年龄65∽75岁,体重50∽80 kg,体重指数≤25 kg/m2;采用随机法,将其分为3组,每组20例：C组（Vt：10 m L/kg）、LV组（Vt：6 m L/kg）和LV＋PEEP组（Vt：6 m L/kg,PEEP：5 cm H2O）。记录麻醉前（T0）、气管插管后仰卧位机械通气10 min（T1）、气管插管后俯卧位机械通气10 min（T2）、气管插管后俯卧位机械通气60 min（T3）、气管拔管后脱氧30 min（T4）的血流动力学指标、血气分析指标及呼吸力学指标。结果三组患者HR、MAP比较差异无统计学意义（P〉0.05）;与LV组同时点比较,C组及LV＋PEEP组机械通气期间Ppeak、Pmean较高（P〈0.05）,但LV＋PEEP组与C组比较,差异无统计学意义（P〉0.05）;LV组及LV＋PEEP组Cldyn明显高于同时点C组（P〈0.05）,但三组患者Cldyn均随着通气时间延长呈下降趋势,其中LV组与LV＋PEEP组差异无统计学意义（P〉0.05）;在T4时点,LV＋PEEP组Pa O2/Fi O2明显高于C组及LV组,A-a DO2低于C组及LV组,差异有统计学意义（P〈0.05）。结论小潮气量联合低水平PEEP（6 m L/kg＋5 cm H2O PEEP）通气能够有效改善全麻俯卧位脊柱手术老年患者术后氧合,提高肺的顺应性,有利于此类手术老年患者呼吸功能的恢复,而且对血流动力学无明显影响。展开更多
When satellite navigation receivers are equipped with multiple antennas, they can deliver attitude information. In previous researches, carrier phase differencing measurement equations were built in the earth-centered...When satellite navigation receivers are equipped with multiple antennas, they can deliver attitude information. In previous researches, carrier phase differencing measurement equations were built in the earth-centered, earth-fixed (ECEF) co- ordinate, and attitude angles could be obtained through the rotation matrix between the body frame (BF) and the local level frame (LLF). Different from the conventional methods, a hybrid algorithm is presented to resolve attitude parameters utilizing the single differencing (SD) carrier phase equations established in LLF. Assuming that the cycle integer ambiguity is known, the measure- ment equations have attitude analytical resolutions by using simultaneous single difference equations for two in-view satellites. In addition, the algorithm is capable of reducing the search integer space into countable 2D discrete points and the ambiguity function method (AFM) resolves the ambiguity function within the analytical solutions space. In the case of frequency division multiple access (FDMA) for the Russian Global Orbiting Navigation Satellite System (GLONASS), a receiver clock bias estimation is employed to evaluate its carrier phase. An evaluating variable and a weighted factor are introduced to assess the integer ambiguity initialization. By static and dynamic ground experiments, the results show that the proposed approach is effective, with enough accuracy and low computation. It can satisfy attitude determination in cases of GPS alone and combined with GLONASS.展开更多
文摘针对室内无线局域网环境下接收信号强度(RSS,received signal strength)样本总体分布不一致而产生较大定位误差的问题,提出了一种基于偏度峰度检验的室内定位算法。利用偏度峰度检验法检验RSS样本是否来自正态总体,接受零假设的样本用正态分布近似其总体分布,拒绝零假设的样本用核函数估计其概率密度。实验结果表明提出算法的定位精度比传统算法提高15%以上,而且在相同的定位精度下,能明显降低离线阶段的工作量。
文摘目的观察不同通气方法对老年全麻俯卧位脊柱手术患者围术期呼吸功能的影响。方法选择拟在全麻俯卧位下行腰骶椎手术的老年患者60例,ASAⅠ或Ⅱ级,性别不限,年龄65∽75岁,体重50∽80 kg,体重指数≤25 kg/m2;采用随机法,将其分为3组,每组20例：C组（Vt：10 m L/kg）、LV组（Vt：6 m L/kg）和LV＋PEEP组（Vt：6 m L/kg,PEEP：5 cm H2O）。记录麻醉前（T0）、气管插管后仰卧位机械通气10 min（T1）、气管插管后俯卧位机械通气10 min（T2）、气管插管后俯卧位机械通气60 min（T3）、气管拔管后脱氧30 min（T4）的血流动力学指标、血气分析指标及呼吸力学指标。结果三组患者HR、MAP比较差异无统计学意义（P〉0.05）;与LV组同时点比较,C组及LV＋PEEP组机械通气期间Ppeak、Pmean较高（P〈0.05）,但LV＋PEEP组与C组比较,差异无统计学意义（P〉0.05）;LV组及LV＋PEEP组Cldyn明显高于同时点C组（P〈0.05）,但三组患者Cldyn均随着通气时间延长呈下降趋势,其中LV组与LV＋PEEP组差异无统计学意义（P〉0.05）;在T4时点,LV＋PEEP组Pa O2/Fi O2明显高于C组及LV组,A-a DO2低于C组及LV组,差异有统计学意义（P〈0.05）。结论小潮气量联合低水平PEEP（6 m L/kg＋5 cm H2O PEEP）通气能够有效改善全麻俯卧位脊柱手术老年患者术后氧合,提高肺的顺应性,有利于此类手术老年患者呼吸功能的恢复,而且对血流动力学无明显影响。
文摘When satellite navigation receivers are equipped with multiple antennas, they can deliver attitude information. In previous researches, carrier phase differencing measurement equations were built in the earth-centered, earth-fixed (ECEF) co- ordinate, and attitude angles could be obtained through the rotation matrix between the body frame (BF) and the local level frame (LLF). Different from the conventional methods, a hybrid algorithm is presented to resolve attitude parameters utilizing the single differencing (SD) carrier phase equations established in LLF. Assuming that the cycle integer ambiguity is known, the measure- ment equations have attitude analytical resolutions by using simultaneous single difference equations for two in-view satellites. In addition, the algorithm is capable of reducing the search integer space into countable 2D discrete points and the ambiguity function method (AFM) resolves the ambiguity function within the analytical solutions space. In the case of frequency division multiple access (FDMA) for the Russian Global Orbiting Navigation Satellite System (GLONASS), a receiver clock bias estimation is employed to evaluate its carrier phase. An evaluating variable and a weighted factor are introduced to assess the integer ambiguity initialization. By static and dynamic ground experiments, the results show that the proposed approach is effective, with enough accuracy and low computation. It can satisfy attitude determination in cases of GPS alone and combined with GLONASS.
