时滞和相关性观测条件下的红外目标状态估计方法

着重对红外跟踪系统目标状态估计过程中存在的观测量滞后和相关性问题进行研究。在目标跟踪过程中,脱靶量信号的滞后导致目标量测位置和真实值间是有误差的,进而通过状态估计得到的目标参数也是不准确的,另外观测量的相关性也降低了估计效果的准确性。对于以上问题,首先利用观测重组技术对时滞观测序列进行重组,将其转化为变结构无时滞观测系统,并在此基础上提出了一种时滞椭球集员估计算法(Delayed ellipsoidal set filter,DESF)。仿真实验结果表明,DESF算法可以有效克服观测序列相关性的影响,同时系统跟踪性能较不考虑观测延迟的情况也有显著提高。     

Modeling and simulation of an industrial‐scale parex process

The Parex unit for industrial‐scale purification of p‐xylene was studied through detailed simulation and the accuracy of the developed model tested against real industrial data. Starting from a comprehensive analysis of the construction and operation of the industrial unit, a simulation model was developed that incorporates the existing three major types of dead volumes: bed lines, which connect the beds to the rotary valve, circulation lines, which connect adjacent adsorbent chambers, and bed‐head dead volumes, which are located upstream of each bed due to the existence of internals. By gathering operation data and surveys in the pumparound line and in the extract stream, three case studies were defined and compared with simulation results. The model is capable of predicting the performance of the industrial unit. Further simulations were made and compared with plant data to assess the effect of adsorbent capacity loss on the long‐term performance of the unit. © 2015 American Institute of Chemical Engineers AIChE J, 61: 1345–1363, 2015     

Interactive tree modeling and deformation with collision detection and avoidance

We present an interactive tree modeling and deformation system that supports an efficient collision detection and avoidance using a bounding volume hierarchy of sweep surfaces. Starting with conventional tree models (given as meshes), we convert them into sweep surfaces and deform their branches interactively while detecting and avoiding collisions with many other branches. Multiple tree models (sharing the same topology) can be generated with great ease using this sweep‐based approach, and they can serve as a basis for the generation of a multiparameter family of trees. We demonstrate the effectiveness of our approach in an automatic generation of similar trees, the colonization of trees to form a forest, and the tree growth, aging, and withering simulations. Copyright © 2015 John Wiley & Sons, Ltd.     

Learning curve analysis of concentrated photovoltaic systems

Price declines and volume growth of concentrated photovoltaic (CPV) systems are analysed using the learning curve methodology and compared with other forms of solar electricity generation. Logarithmic regression analysis determines a learning rate of 18% for CPV systems with 90% confidence of that rate being between 14 and 22%, which is higher than the learning rates of other solar generation systems (11% for CSP and 12 to 14% for PV). Current CPV system prices are competitive with PV and CSP, which, when combined with the higher learning rate, indicates that CPV is likely to further improve its marketability. A target price of 1 $/W in 2020 could be achieved with a compound growth rate of 67% for the total deployed volume between 2014 and 2020, which would realize a cumulative deployed volume of 7900 MW. Other projections of deployment volumes from commercial sources are converted using the learning rate into future price scenarios, resulting in predicted prices in the range of 1.1 to 1.3 $/W in 2020. © 2014 The Authors. Progress in Photovoltaics: Research and Applications published by John Wiley & Sons Ltd.     

一种用于计算机辅助产物设计中基于BP-NN优化问题的求解方法

Because of the powerful mapping ability, back propagation neural network (BP-NN) has been employed in computer-aided product design (CAPD) to establish the property prediction model. The backward problem in CAPD is to search for the appropriate structure or composition of the product with desired property, which is an optimization problem. In this paper, a global optimization method of using the a BB algorithm to solve the backward problem is presented. In particular, a convex lower bounding function is constructed for the objective function formulated with BP-NN model, and the calculation of the key parameter a is implemented by recurring to the interval Hessian matrix of the objective function. Two case studies involving the design of dopamine β-hydroxylase (DβH) inhibitors and linear low density polyethylene (LLDPE) nano composites are investigated using the proposed method.     

弹簧卷绕仿真系统中的碰撞检测

由于数控卷簧机卷绕刀具较多且刀具的运动时序较为复杂,因此对刀具之间可能发生的碰撞进行检测尤为重要。结合弹簧卷绕的动作特点,采用基于轴向包围盒的碰撞检测算法对可能产生碰撞的物体在仿真系统中进行了碰撞检测,对包围盒的表示、干涉及碰撞响应等作了阐述。实验表明,系统增强了仿真画面的真实感和实用性,操作者可以根据碰撞仿真结果进行处理,从而有效避免了在实际卷簧过程中刀具间可能产生的相互碰撞。     

复合型粉煤灰早期活性激发剂的研制

从24种可能具有激发粉煤灰早期活性的试剂中，采用单组分比选、双组分配伍及正交优化掺量的技术途径，配制了3种效果显著的激发剂配方，并将其应用于高掺量粉煤灰混凝土的室内试验中，且激发效果良好．根据粉煤灰-水泥浆体的扫描电子显微镜图像，探讨了粉煤灰活性激发剂的激发机理．     

图像目标外接多边形及凸壳的一种构造方法

对二值图像进行Hough变换后,在(ρ,θ)空间中选取了一组边界对应点,通过计算与这些边界对应点对应的图像空间中直线的交点,构造了图像目标的外接多边形;通过比较相距π/2 rad的投影区间长度是否相等,或区间长度的乘积是否为最小,得到了形状外接正方形和外接最小面积矩形;利用构造形状外接多边形的方法并通过增加边的数目,构造了形状的近似凸壳.实验和理论分析表明,文中算法具有好的抗噪性能和广泛的适用范围.     

新的文本图像倾斜检测及校正算法

在文档扫描过程中,文档可能会发生倾斜,而很多字符识别和布局分析算法都对倾斜十分敏感,文本图像的倾斜检测及校正就成为文档分析不可缺少的环节.提出了一种新的倾斜文本图像的校正方法,该方法首先获取文档图像的bounding box,以bounding box面积最小作为倾斜校正的最终目标,并使用遗传算法搜索该最小值.实验结果表明,该算法对倾斜角的检测具有较高的精确度.     

基于OBE算法的混沌通信盲干扰抑制

文章提出了基于最优边界椭球（OBE）准则的混沌通信窄带干扰自适应算法。与基于最小相空间体积（MPSV）的Kalman滤波和双重平方根无迹卡尔曼滤波（SRUKF）算法相比，该算法不需要估计干扰模型的参数，并且具有选择更新特性，能在仅有少量数据参与更新的情况下达到与前者接近的性能，有效降低了计算量。该方法的性能通过在差分混沌相移键控（DCSK）通信下对AR型和单音两种窄带干扰的有效抑制得到了验证。