无线传感器网络(wireless sensor network,WSN)由多个微传感器节点组成,定位技术是无线传感器网络技术的重要应用之一。目前,许多定位算法在视距(line of sight,LOS)环境下定位精度较高,但在非视距(non line of sight,NLOS)环境下的定...无线传感器网络(wireless sensor network,WSN)由多个微传感器节点组成,定位技术是无线传感器网络技术的重要应用之一。目前,许多定位算法在视距(line of sight,LOS)环境下定位精度较高,但在非视距(non line of sight,NLOS)环境下的定位精度较差。为了解决这一问题,提出一种改进的基于到达时间的最大熵模糊概率数据关联算法。采用分组的思想将N个测量值分为L组,每组通过交互式多模型(interactive multi model,IMM)算法获得相应的移动节点位置估计、模型概率和协方差矩阵。然后将得到的L个位置估计,通过验证门进行非视距检测,丢弃被非视距误差污染的位置估计,利用相应的关联概率对正确的位置估计进行加权得到最终的位置估计。仿真和实验结果表明,与现有方法相比,该算法可以减轻非视距误差的影响,实现更高的定位精度。展开更多
A probabilistic method based on principle of maximum entropy was employed to analyze the randomness of contact force between geomembrane and granular material.The contact force distribution is exponential according to...A probabilistic method based on principle of maximum entropy was employed to analyze the randomness of contact force between geomembrane and granular material.The contact force distribution is exponential according to the proposed method and the grain size is the most important factor that affects the distribution of contact force.The proposed method is then verified by a series of laboratory experiments using glass beads and cobbles as granular material and a very thin pressure,indicating that film is firstly used in these experiments which give a reliable method to measure the contact force at each contact point.展开更多
The paper introduces a new approach to estimating the T-year return-period wave height (TRPW), i.e. the wave height expected to occur in T-year, from two sets of observed extreme data and on the basis of the maximum e...The paper introduces a new approach to estimating the T-year return-period wave height (TRPW), i.e. the wave height expected to occur in T-year, from two sets of observed extreme data and on the basis of the maximum entropy principle. The main points of the approach are as follows. 1) A maximum entropy probability density function (PDF) for the extreme wave height H is derived from a Euler equation subject to some necessary and rational constraints. 2) The parameters in the function are expressed in terms of the mth moment of H. 3) This PDF is convenient to theoretical and practical applications as it is simple and its four parameters are easy to be determined from observed extreme data. An example is given for estimating the TRPW in 50 and 100 years by the present approach and by some currently used methods using observed data at two hydrographic stations.The comparison of the estimated results shows that the present approach is quite similar to the Pearson-Ⅲ and Gumbel methods.展开更多
文摘无线传感器网络(wireless sensor network,WSN)由多个微传感器节点组成,定位技术是无线传感器网络技术的重要应用之一。目前,许多定位算法在视距(line of sight,LOS)环境下定位精度较高,但在非视距(non line of sight,NLOS)环境下的定位精度较差。为了解决这一问题,提出一种改进的基于到达时间的最大熵模糊概率数据关联算法。采用分组的思想将N个测量值分为L组,每组通过交互式多模型(interactive multi model,IMM)算法获得相应的移动节点位置估计、模型概率和协方差矩阵。然后将得到的L个位置估计,通过验证门进行非视距检测,丢弃被非视距误差污染的位置估计,利用相应的关联概率对正确的位置估计进行加权得到最终的位置估计。仿真和实验结果表明,与现有方法相比,该算法可以减轻非视距误差的影响,实现更高的定位精度。
基金Project(51079047)supported by the National Natural Science Foundation of ChinaProject Funded by the Priority Academic Program of Jiangsu Higher Education Institutions,China
文摘A probabilistic method based on principle of maximum entropy was employed to analyze the randomness of contact force between geomembrane and granular material.The contact force distribution is exponential according to the proposed method and the grain size is the most important factor that affects the distribution of contact force.The proposed method is then verified by a series of laboratory experiments using glass beads and cobbles as granular material and a very thin pressure,indicating that film is firstly used in these experiments which give a reliable method to measure the contact force at each contact point.
基金the Natural Science Foundation of China under Contract No.40706012the Young Scientist Foundation of State Oceanic Administration under Contract No.2008209+1 种基金the Basic Science Operational Fund of the Ministry of Finance assigned to the Third Institute of Oceanography,State Oceanic Administration under Contract No.2007010‘863’program No.2006AA09A301
文摘The paper introduces a new approach to estimating the T-year return-period wave height (TRPW), i.e. the wave height expected to occur in T-year, from two sets of observed extreme data and on the basis of the maximum entropy principle. The main points of the approach are as follows. 1) A maximum entropy probability density function (PDF) for the extreme wave height H is derived from a Euler equation subject to some necessary and rational constraints. 2) The parameters in the function are expressed in terms of the mth moment of H. 3) This PDF is convenient to theoretical and practical applications as it is simple and its four parameters are easy to be determined from observed extreme data. An example is given for estimating the TRPW in 50 and 100 years by the present approach and by some currently used methods using observed data at two hydrographic stations.The comparison of the estimated results shows that the present approach is quite similar to the Pearson-Ⅲ and Gumbel methods.
