Human Visual Attention Mechanism-Inspired Point-and-Line Stereo Visual Odometry for Environments with Uneven Distributed Features

Visual odometry is critical in visual simultaneous localization and mapping for robot navigation.However,the pose estimation performance of most current visual odometry algorithms degrades in scenes with unevenly distributed features because dense features occupy excessive weight.Herein,a new human visual attention mechanism for point-and-line stereo visual odometry,which is called point-line-weight-mechanism visual odometry(PLWM-VO),is proposed to describe scene features in a global and balanced manner.A weight-adaptive model based on region partition and region growth is generated for the human visual attention mechanism,where sufficient attention is assigned to position-distinctive objects(sparse features in the environment).Furthermore,the sum of absolute differences algorithm is used to improve the accuracy of initialization for line features.Compared with the state-of-the-art method(ORB-VO),PLWM-VO show a 36.79%reduction in the absolute trajectory error on the Kitti and Euroc datasets.Although the time consumption of PLWM-VO is higher than that of ORB-VO,online test results indicate that PLWM-VO satisfies the real-time demand.The proposed algorithm not only significantly promotes the environmental adaptability of visual odometry,but also quantitatively demonstrates the superiority of the human visual attention mechanism.

Breeding Report of New Mung Bean Variety"JiHeilv No.12"

The mung bean variety Ji Heilv No.12 was bred by Institute of Characteristic Crop Research, Chongqing Academy of Agricultural Sciences and Institute of Food and Oil Crops, Hebei Academy of Agricultural and Forestry Sciences. using Jilv 9and Jilv 7 as female and male parent respectively,with pedigree method. Ji Heilv No.12 is a new variety with features of high and stable yield,broad adaptability and strong resistance in yield trails during 2011-2012; it was approved and released by Chongqing Provincial Committee of Crop Variety Identification in 2012,suitable for cultivating in most area of Chongqing.

Full-parameter constrained parsimonious subspace identification with steady-state information for DC–DC converters

A full-parameter constrained parsimonious subspace identification method that incorporates the steady-state a priori infor-mation of the system is proposed to model the DC-DC converters.A parsimonious model with fewer parameters is used to represent the system,and then an optimal weighted methods is used to estimate the system parameters matrices by taking into account both dynamical data and steady-state data.Compared with traditional data-driven methods for DC-DC convert-ers,the subspace-based method can simultaneously estimate model structure and parameter with appropriate computational complexity.Moreover,compared with the traditional full-parameter constrained subspace approach,the proposed algorithm can accurately estimate the system parameters with a smaller variance.The experimental results on a DC-DC synchronous buck converter verify the effectiveness and superiority of the proposed method.

村镇简易装配式异形柱及其钢框架结构体系设计及施工关键技术研究

随着村镇地区的发展,村镇居民对住房有了更高层次需求,新农村建设中装配式和绿色建造的重要性逐步提高。针对村镇地区低层居民住宅建筑,提出了新型简易装配式异形柱及其钢框架结构体系。首先,描述了新型简易装配式异形柱的构造、节点形式及其特点。该异形柱由3根单柱组成,单柱的截面形式为矩形,3个单柱按L形排列;单柱与U形连接件、L形连接件通过自攻螺钉固接而成;基于该异形柱的连接节点均采用自攻螺钉进行连接,完全不使用焊接。该体系具有“一小二低三易”的优点,即:环境污染小、操作难度低、经济成本低、钢材购买易、构件运输易、装配过程易,满足国家乡村振兴战略对住宅绿色建造的发展需求。然后,基于新型结构体系,借助PKPM建立了该房屋工程的计算模型,完成了该房屋工程结构分析与设计,得到了结构的各项指标与不同工况下的变形图,参考相关规范对节点进行了设计与验算。最后,总结了施工过程中遇到的难点:梁柱节点以及梁梁节点的施工作业面较高,高空操作难度大且存在安全隐患;该新型体系的安装尽量避免使用大型机械,人工直接抬升构件操作难度过大,容易在抬升的过程中对节点造成破坏,且存在安全隐患,针对其提出了3项关键施工技术:自攻螺钉节点简化连接方法、双梯抬升法和框架抬升临时固定措施。其中,自攻螺钉节点简化连接方法提升了自攻螺钉节点连接的效率与准确性,提高了施工的安全性;双梯抬升法降低了人工抬升构件的难度,避免了节点在抬升过程中发生破坏,提高了构件抬升的效率与安全性;框架抬升临时固定措施避免了框架在人工抬升的过程中发生侧翻,提升了框架抬升的安全性。以上3项关键技术提高了新型简易装配式异形柱结构在施工过程中的效率与安全性。