近场源距离、频率及到达角联合估计算法

本文提出了一种近场源距离、频率及到达角(DOA)三维参数联合估计算法.该算法不需谱峰搜索且各参数自动配对.由于算法使用了四阶累积量,所以适用于任意加性高斯噪声环境.     

一种新的移动IPv6移动性管理策略

在IETF制定的移动IPv6移动性管理策略中,当移动主机每次从一个子网移动到另一个子网时,都需要对家乡代理和相应的通信主机进行绑定更新,这就导致网络总的绑定和发送代价过高.本文提出了一种新的移动性管理策略,在利用现有网络结构的基础上,通过将移动主机的移动分为本地移动和家乡移动两种类型,来减少移动主机向家乡代理和相应的通信主机发送绑定更新消息,从而降低网络的绑定代价,使网络的性能得到改善.     

基于未确知数理论的一种新的费用估算专家预测方法

分析了定性专家预测方法在费用估算及其不确定性分析中的重要作用,通过运用未确知数在描述主观认识不确定性方面的优势,发展了一种新的航天型号费用估算专家预测方法,应用示例表明,这种方法十分有简便有效。     

一种新的基于极大似然估计的系统辨识方法

进化计算是一种基于自然选择和自然变异机制的并行随机优化算法。由于递推极大似然估计法难以实现性能指标函数的全局寻优，所以本文提出了将改进的进化计算用于系统参数辨识的方法。计算机仿真结果表明，该算法能够实现似然函数的全局寻优。     

Experimental investigations on solar chimney for room ventilation

Experimental investigations on a small size solar chimney show that the rate of ventilation increases with increase of the ratio between height of absorber and gap between glass and absorber. This finding is in agreement with results of the steady-state mathematical model developed for analysis of such systems. Nine different combination of absorber height and air gap have been investigated on the experimental set-up. Highest rate of ventilation induced with the help of solar energy was found to be 5.6 air change per hour in a room of 27 m³, at solar radiation 700 W/m² on vertical surface with the stack height-air gap ratio of 2.83 for a 1 m high chimney.     

碳纳米纤维吸附储氢性能评价

利用N2(T=77K)、H2(T=298K)在三种碳纳米纤维材料中的吸附等温线，对这三种材料的吸附储氢性能进行了评价。以N2在77K下的吸附等温线为基础，分别用BET方法和BJH方法计算了这三种材料的比表面积和孔径分布，讨论了比表面积、孔径分布和吸附性能之间的关系。计算和实验结果表明：这三种材料均只含有少量的微孔，吸附性能较差。在三种后处理方法中，以水蒸气氧化法的效果最好，所得材料比表面积最大，微孔容积所占比例也最大，相应的吸附性能也最好。     

水轮机导叶分段关闭的灰色决策

本文对灰色局势决策作点滴引伸，结合正交设计对水轮机导叶分段关闭作寻优分析，与一般加权法比较说明，灰色决策法具有算法直观简便，概念清楚和准确度高等特点。     

Giving Direction to Motion and Surface with Ultra‐Fast Speed Using Oriented Hydrogel Fibers

Thermoresponsive hydrogel fibrous membranes showing directionally controlled movements and surface change with ultra‐fast speed are presented for the first time. They show reversible coiling, rolling, bending, and twisting deformations in different controllable directions for many cycles (at least 50 cycles tried) with inside‐out change in surfaces and shapes. Speed, reversibility, large‐scale deformations and, most importantly, control over the direction of deformation is required in order to make synthetic actuators inspired from natural materials or otherwise. A polymeric synthetic material combining all these properties is still awaited. This issue is addressed and provide a very simple system fulfilling all these requirements by combining porosity and asymmetric swelling/shrinking via orientation of hydrogel fibers at different angles in a fibrous membrane. Electrospinning is used as a tool for making membranes with fibers oriented at different angles.     

匀加速运动平台下的大斜视DBS成像方法

 距离走动校正和二次相位误差补偿是匀加速运动平台下大斜视DBS成像的难点.因此,本文提出一种基于Radon变换校正距离走动、基于Radon模糊变换补偿二次相位误差的DBS成像算法,并推导了此校正和补偿算法的空域适应性条件.该算法原理简单、精度高,且无需雷达平台运动参数、视角等先验信息,可实现预定方位分辨率的DBS成像.仿真实验验证了算法的有效性.     

Aggregate volumetric estimation based on PCA and momentum-enhanced BP neural network

This paper proposes a Back Propagation (BP) neural network with momentum enhance-ment aiming to achieving the smooth convergence for aggregate volumetric estimation purpose. Net-work inputs are first selected by optically measuring the eight geometry-related parameters from the given particle image. To simplify the network structure, principal component analysis technique is applied to reduce the input dimension. The specific network structure is finalized based on both em-pirical expertise and analysis on selecting the appropriate number of neurons in hidden layer. The network is trained using the finite number of randomly-picked particles. The training and test results suggest that, compared to the generic BP network, the training duration of the proposed neural network is greatly attenuated, the complexity of the network structure is largely reduced, and the es-timation precision is within 2%, being sufficiently up to technical satisfaction.