Walking is the most basic and essential part of the activities of daily living. To enable the elderly and non-ambulatory gait-impaired patients, the repetitive practice of this task, a novel gait training robot(GTR) w...Walking is the most basic and essential part of the activities of daily living. To enable the elderly and non-ambulatory gait-impaired patients, the repetitive practice of this task, a novel gait training robot(GTR) was designed followed the end-effector principle, and an active partial body weight support(PBWS) system was introduced to facilitate successful gait training. For successful establishment of a walking gait on the GTR with PBWS, the motion laws of the GTR were planned to enable the phase distribution relationships of the cycle step, and the center of gravity(COG) trajectory of the human body during gait training on the GTR was measured. A coordinated control strategy was proposed based on the impedance control principle. A robotic prototype was developed as a platform for evaluating the design concepts and control strategies. Preliminary gait training with a healthy subject was implemented by the robotic-assisted gait training system and the experimental results are encouraging.展开更多
Let {Xn, n≥1} be a martingale difference sequence and {a nk , 1?k?n,n?1} an array of constant real numbers. The limiting behavior of weighted partial sums ∑ k=1 n a nk X k is investigated and some new results are ob...Let {Xn, n≥1} be a martingale difference sequence and {a nk , 1?k?n,n?1} an array of constant real numbers. The limiting behavior of weighted partial sums ∑ k=1 n a nk X k is investigated and some new results are obtained.展开更多
The purpose of this study is to reveal the effects of historic climate change on rice yield over the middle and lower reaches of the Yangtze River, China, and to better adapt to climate change in the future. This stud...The purpose of this study is to reveal the effects of historic climate change on rice yield over the middle and lower reaches of the Yangtze River, China, and to better adapt to climate change in the future. This study presents the relation of temperature and precipitation and rice components from 1981 to 2003 at 48 early rice stations and 30 middle rice stations. It focuses on an analysis of three stages： flowering, pre-milk, and late milk. The results show that mean maximum temperature and mean daily precipitation at the stages of flowering and pre-milk are most related to early rice yield. Yield change of middle rice is mainly because of mean precipitation change at the flowering stage. Furthermore, percentage of undeveloped grain increases as mean maximum temperature rises at the flowering stage. Over-precipitation in the reproductive stage is a major reason for reduction in yield of early rice. Consecutive rainfall and continuous high temperature can have negative effects on middle rice yield. Global warming would affect middle rice more seriously than early rice.展开更多
Consider a sequence of i.i.d.positive random variables.An universal result in almost sure limit theorem for products of sums of partial sums is established.We will show that the almost sure limit theorem holds under a...Consider a sequence of i.i.d.positive random variables.An universal result in almost sure limit theorem for products of sums of partial sums is established.We will show that the almost sure limit theorem holds under a fairly general condition on the weight dk= k-1 exp（lnβk）,0≤β〈1.And in a sense,our results have reached the optimal form.展开更多
Let {Xn, n ≥ 1} be a sequence of independent and identically distributed positive valued random variables with a common distribution function F. When F belongs to the domain of partial attraction of a semi stable law...Let {Xn, n ≥ 1} be a sequence of independent and identically distributed positive valued random variables with a common distribution function F. When F belongs to the domain of partial attraction of a semi stable law with index α, 0 < α < 1, an asymptotic behavior of the large deviation probabilities with respect to properly normalized weighted sums have been studied and in support of this we obtained Chover’s form of law of iterated logarithm.展开更多
It becomes a key technology to measure the concentration of the vehicle exhaust components with the absorption spectra. But because of the overlap of gas absorption bands, how to separate the absorption information of...It becomes a key technology to measure the concentration of the vehicle exhaust components with the absorption spectra. But because of the overlap of gas absorption bands, how to separate the absorption information of each component gas from the mixed absorption spectra has become the key point to restrict the precision of the optical detection method. In this paper, the ex-perimental platform for the absorption spectrum of vehicle exhaust components has been established. Based on the ultraviolet absorption spectra measured with the platform of exhaust gas NO & NO2, the concentration regression model for the two components has been established with weighted partial least squares regression (WPLS). Finally the each spectral characteristic information of NO & NO2 gas has been separated and the concentration of each corresponding component has been reversed successfully.展开更多
Consider the regression model Y=Xβ+ g(T) + e. Here g is an unknown smoothing function on [0, 1], β is a l-dimensional parameter to be estimated, and e is an unobserved error. When data are randomly censored, the est...Consider the regression model Y=Xβ+ g(T) + e. Here g is an unknown smoothing function on [0, 1], β is a l-dimensional parameter to be estimated, and e is an unobserved error. When data are randomly censored, the estimators βn* and gn*forβ and g are obtained by using class K and the least square methods. It is shown that βn* is asymptotically normal and gn* achieves the convergent rate O(n-1/3).展开更多
面粉吸水率是评价面粉质量和预测面制品加工特性的重要品质性状。面粉吸水率的测定主要参照国际或国家标准利用粉质仪进行,其测定方法费时费力。基于此,提出利用可见近红外光谱分析技术结合多元统计分析进行面粉吸水率快速、无损检测。...面粉吸水率是评价面粉质量和预测面制品加工特性的重要品质性状。面粉吸水率的测定主要参照国际或国家标准利用粉质仪进行,其测定方法费时费力。基于此,提出利用可见近红外光谱分析技术结合多元统计分析进行面粉吸水率快速、无损检测。参照国标法测定150份小麦面粉样品的吸水率,面粉吸水率变幅为53.10%~74.50%。利用可见近红外分析仪采集面粉样品的光谱信息,有效光谱范围为570~1100 nm。采用偏最小二乘回归(PLSR)、主成分回归(PCR)和支持向量机回归(SVR)将光谱信息和面粉吸水率进行关联,分别建立面粉吸水率的定量分析预测模型,筛选最优的建模方法。在优选的建模方法的基础上,采用竞争性自适应重加权(CARS)、区间随机蛙跳(iRF)、迭代保留信息变量(IRIV)和连续投影(SPA)算法提取特征波长,筛选最优的特征波长提取算法。基于最优的建模方法和最优的特征波长提取算法提取的特征波长,采用标准化(NL)、一阶求导(1 st Der)、基线校正(BL)、标准正态变换(SNV)和去趋势化(DT)5种光谱预处理方法对特征波长的光谱进行预处理,筛选最优的光谱预处理方法。结果表明,采用NL光谱预处理方法对CARS算法提取的24个特征波长(仅占原始波长的2.26%)的光谱进行预处理后建立的PLSR模型性能最佳,预测集相关系数(R_(p)^(2))、预测集均方根误差(RMSEP)和预测相对分析误差(RPD)分别为0.8894、1.4585和2.6413。采用CARS算法提取的特征波长所建的模型不仅能提高模型的性能,还很大程度提高模型运算效率、降低仪器制造成本和光谱仪微型化的难度,从而为面粉吸水率可见近红外无损、快速检测研究奠定了基础。展开更多
基金Project(61175128) supported by the National Natural Science Foundation of ChinaProject(2008AA040203) supported by the National High Technology Research and Development Program of China
文摘Walking is the most basic and essential part of the activities of daily living. To enable the elderly and non-ambulatory gait-impaired patients, the repetitive practice of this task, a novel gait training robot(GTR) was designed followed the end-effector principle, and an active partial body weight support(PBWS) system was introduced to facilitate successful gait training. For successful establishment of a walking gait on the GTR with PBWS, the motion laws of the GTR were planned to enable the phase distribution relationships of the cycle step, and the center of gravity(COG) trajectory of the human body during gait training on the GTR was measured. A coordinated control strategy was proposed based on the impedance control principle. A robotic prototype was developed as a platform for evaluating the design concepts and control strategies. Preliminary gait training with a healthy subject was implemented by the robotic-assisted gait training system and the experimental results are encouraging.
基金SupportedbytheNationalNaturalScienceFoundationofChina (No .10 0 710 5 8)and (No .10 0 710 19)
文摘Let {Xn, n≥1} be a martingale difference sequence and {a nk , 1?k?n,n?1} an array of constant real numbers. The limiting behavior of weighted partial sums ∑ k=1 n a nk X k is investigated and some new results are obtained.
文摘The purpose of this study is to reveal the effects of historic climate change on rice yield over the middle and lower reaches of the Yangtze River, China, and to better adapt to climate change in the future. This study presents the relation of temperature and precipitation and rice components from 1981 to 2003 at 48 early rice stations and 30 middle rice stations. It focuses on an analysis of three stages： flowering, pre-milk, and late milk. The results show that mean maximum temperature and mean daily precipitation at the stages of flowering and pre-milk are most related to early rice yield. Yield change of middle rice is mainly because of mean precipitation change at the flowering stage. Furthermore, percentage of undeveloped grain increases as mean maximum temperature rises at the flowering stage. Over-precipitation in the reproductive stage is a major reason for reduction in yield of early rice. Consecutive rainfall and continuous high temperature can have negative effects on middle rice yield. Global warming would affect middle rice more seriously than early rice.
基金Supported by the National Natural Science Foundation of China(11061012)Project Supported by Program to Sponsor Teams for Innovation in the Construction of Talent Highlands in Guangxi Institutions of Higher Learning([2011]47)the Guangxi Natural Science Foundation of China(2012GXNSFAA053010)
文摘Consider a sequence of i.i.d.positive random variables.An universal result in almost sure limit theorem for products of sums of partial sums is established.We will show that the almost sure limit theorem holds under a fairly general condition on the weight dk= k-1 exp（lnβk）,0≤β〈1.And in a sense,our results have reached the optimal form.
文摘Let {Xn, n ≥ 1} be a sequence of independent and identically distributed positive valued random variables with a common distribution function F. When F belongs to the domain of partial attraction of a semi stable law with index α, 0 < α < 1, an asymptotic behavior of the large deviation probabilities with respect to properly normalized weighted sums have been studied and in support of this we obtained Chover’s form of law of iterated logarithm.
文摘It becomes a key technology to measure the concentration of the vehicle exhaust components with the absorption spectra. But because of the overlap of gas absorption bands, how to separate the absorption information of each component gas from the mixed absorption spectra has become the key point to restrict the precision of the optical detection method. In this paper, the ex-perimental platform for the absorption spectrum of vehicle exhaust components has been established. Based on the ultraviolet absorption spectra measured with the platform of exhaust gas NO & NO2, the concentration regression model for the two components has been established with weighted partial least squares regression (WPLS). Finally the each spectral characteristic information of NO & NO2 gas has been separated and the concentration of each corresponding component has been reversed successfully.
文摘Consider the regression model Y=Xβ+ g(T) + e. Here g is an unknown smoothing function on [0, 1], β is a l-dimensional parameter to be estimated, and e is an unobserved error. When data are randomly censored, the estimators βn* and gn*forβ and g are obtained by using class K and the least square methods. It is shown that βn* is asymptotically normal and gn* achieves the convergent rate O(n-1/3).
文摘面粉吸水率是评价面粉质量和预测面制品加工特性的重要品质性状。面粉吸水率的测定主要参照国际或国家标准利用粉质仪进行,其测定方法费时费力。基于此,提出利用可见近红外光谱分析技术结合多元统计分析进行面粉吸水率快速、无损检测。参照国标法测定150份小麦面粉样品的吸水率,面粉吸水率变幅为53.10%~74.50%。利用可见近红外分析仪采集面粉样品的光谱信息,有效光谱范围为570~1100 nm。采用偏最小二乘回归(PLSR)、主成分回归(PCR)和支持向量机回归(SVR)将光谱信息和面粉吸水率进行关联,分别建立面粉吸水率的定量分析预测模型,筛选最优的建模方法。在优选的建模方法的基础上,采用竞争性自适应重加权(CARS)、区间随机蛙跳(iRF)、迭代保留信息变量(IRIV)和连续投影(SPA)算法提取特征波长,筛选最优的特征波长提取算法。基于最优的建模方法和最优的特征波长提取算法提取的特征波长,采用标准化(NL)、一阶求导(1 st Der)、基线校正(BL)、标准正态变换(SNV)和去趋势化(DT)5种光谱预处理方法对特征波长的光谱进行预处理,筛选最优的光谱预处理方法。结果表明,采用NL光谱预处理方法对CARS算法提取的24个特征波长(仅占原始波长的2.26%)的光谱进行预处理后建立的PLSR模型性能最佳,预测集相关系数(R_(p)^(2))、预测集均方根误差(RMSEP)和预测相对分析误差(RPD)分别为0.8894、1.4585和2.6413。采用CARS算法提取的特征波长所建的模型不仅能提高模型的性能,还很大程度提高模型运算效率、降低仪器制造成本和光谱仪微型化的难度,从而为面粉吸水率可见近红外无损、快速检测研究奠定了基础。
