基于ORB-SLAM的室内机器人定位和三维稠密地图构建

针对在室内机器人定位和三维稠密地图构建系统中,现有方法无法同时满足高精度定位、大范围和快速性要求的问题,应用具有跟踪、地图构建和重定位三平行线程的ORB-SLAM算法估计机器人三维位姿;然后拼接深度摄像头KINECT获得的三维稠密点云,提出空间域上的关键帧提取方法剔除冗余的视频帧;接着提出子地图法进一步减少地图构建的时间,最终提高算法的整体速度。实验结果表明,所提系统能够在大范围环境中准确定位机器人位置,在运动轨迹为50 m的大范围中,机器人的均方根误差为1.04 m,即误差为2%,同时整体速度为11帧/秒,其中定位速度达到17帧/秒,可以满足室内机器人定位和三维稠密地图构建的精度、大范围和快速性的要求。     

基于强挂起弱预测机制的负载均衡模型研究

大数据时代的快速发展和大数据战略的明确提出,使得Web服务器集群将面临更加复杂和严峻的负载挑战。传统的负载均衡算法存在着明显的局限性。提出了一种基于强挂起弱预测机制的负载均衡模型,该模型利用强挂起机制和基于层次分析的三次指数平滑预测算法进行负载均衡动态调度。实验结果表明该模型在系统瞬时性能异常、高并发和重负载交互情况下的负载均衡效果优于传统负载均衡算法。     

Neuroergonomics: Research and practice

This article describes the characteristics and scope of neuroergonomics, defined as the study of brain and behaviour at work. Neuroergonomics focuses on investigations of the neural bases of mental functions and physical performance in relation to technology, work, leisure, transportation, health care and other settings in the real world. The two major goals of neuroergonomics are to use knowledge of brain function and human performance to design technologies and work environments for safer and more efficient operation, and to advance understanding of brain function underlying real-world human performance. The conceptual, theoretical and philosophical issues at the core of neuroergonomics--that lie at the confluence of cognitive science, neuroscience, and ergonomics--are discussed. Adaptive human-machine systems are then described as an illustration of neuroergonomic research. Several other examples of neuroergonomic research and practice are also described.     

A discipline for research needs in cognitive ergonomics

Research needs in Cognitive Ergonomics are many and varied, as attested by this special issue. However, research is only one component of the discipline to which Cognitive Ergonomics aspires. To ground these research needs, and so to contribute to their future satisfaction, this paper argues for a meta-need, that of relating them to other discipline components, such as scope, practice and knowledge. The past, present and future of Cognitive Ergonomics are reviewed as a discipline, so relating research to these other components. An historical view is taken, which characterizes the past, present and future of Cognitive Ergonomics. The past, and in particular its shortcomings--as lessons awaiting to be learned-- is described in terms of an earlier characterization offered by Long. The present is described in terms of the lessons assumed to have been learned by Cognitive Ergonomics since that publication. The future is characterized in terms of lessons which still remain to be learned, that is, research needs to be satisfied. The lessons remaining are exemplified in the form of a model of planning and control of multiple-task work in medical reception and a design method. Lastly, the paper argues the need for consensus concerning the discipline of Cognitive Ergonomics, including its research knowledge and practices, as a pre-requisite for meeting the research needs identified by the papers in this special issue.     

Statutory reform of aspects of construction law in Australia

Construction contract law in the common law world is largely free of direct statutory intervention. The agenda of calls within the United Kingdom to remedy major defects in construction law is used as a framework in a series of comparisons with recent legislation and practice in Australia, notably in Victoria where a holistic approach to the industry's problems has been adopted with signal success. It is suggested that policy makers in the UK consider what Commonwealth jurisdictions have to offer to the solution of homegrown problems.     

现代港口与城市发展的关系——以江苏省镇江市为例

镇江是一座历史文化名城,素有“天下第一江山”之美誉,它的形成发展与其港口是密不可分的。本文从镇江港口空间形态、城市空间形态、港口与城市发展的关系为切入点,寻求港城空间发展对策。     

Measurement of Bulk Mechanical Properties and Modeling the Load-Response of Rootzone Sands. Part 1: Round and Angular Monosize and Binary Mixtures

The bulk mechanical properties of two different types of rootzone sands (round and angular) were measured using a cubical triaxial tester. Two monosize sands (d 50 = 0.375 mm and 0.675 mm) and their 50:50 binary mixtures (d 50 = 0.500 mm) were studied. The compression, shear, and failure responses of the above-mentioned six compositions were analyzed, compared, and modeled. Two elastic parameters (bulk and shear moduli) and two elastoplastic parameters (swelling and consolidation indices) of the six sand compositions were also calculated and compared. The angular sand was more compressible than round sand during isotropic compression. In addition, the angular sands tended to have lower initial bulk density and high porosity values. Among the three different size fractions, the 0.375 mm mixture was least compressible for both sand shapes. The failure strength and shear modulus of the angular sand were higher than the round sands. In addition, due to their simplicity, phenomenological models were developed to predict the compression and shear behavior of the sands. The prediction models were validated using subangular and subround sands. Average relative difference values were calculated to determine the effectiveness of the prediction models. The mean average relative difference values for compression profiles, i.e., volumetric stress vs. volumetric strain, were from 16 % to 39 %, except for the initial load-response portion (< 1 % volumetric strain). The predictive models were effective in reproducing the failure responses: at 17.2 kPa confining pressure, the mean of average relative difference was 23 %; at 34.5 kPa , the mean difference was 24 %.     

Note To The Mixed-Type Splitting Iterative Method For The Positive Real Linear System

In [5] a new iterative method is given for the linear system of equations Au=b , where A is large, sparse and nonsymmetrical and A^{rm T}+A is symmetric and positive definite (SPD) or equivalently A is positive real. The new iterative method is based on a mixed-type splitting of the matrix A and is called the mixed-type splitting iterative method. The iterative method contains an auxiliary matrix D_1 that is restricted to be symmetric. In this note, the auxiliary matrix is allowed to be more general and it is shown that by proper choice of D 1 , the new iterative method is still convergent. It is also shown that by special choice of D_{1} , the new iterative method becomes the well-known (point) accelerated overrelaxation (AOR) [1] method. Hence, it is shown that the (point) AOR method applied to the positive real system is convergent under the proper choice of the overrelaxation parameters y and .     

Impact of β‐glucan and other oat flour components on physico‐chemical and sensory properties of extruded oat cereals

Whole oat flour, N979‐5‐2‐4 (N979), IA95111 (IA95), ‘Jim’ and ‘Paul’ with β‐glucan concentration of 8.6%, 7.6%, 5.3%, and 5.9%, respectively, was made into extruded breakfast cereal (EBC). EBC β‐glucan had greater peak molecular weight than corresponding whole oat flour. Both whole oat flour and EBC from N979 and IA95 had greater peak viscosity (PV), as measured using a Rapid ViscoAnalyser, than that from Jim or Paul. Bile acid binding of EBC, correlated with total β‐glucan concentrations and PV, was either similar or greater than that of corresponding whole oat flour. Jim EBC had the least expansion ratio, lowest brown colour and cereal aroma but greatest tooth packing values. Paul and N979 EBC, although different from each other in a few sensory attributes, had similar acceptability as judged from a consumer test, suggesting that oats with elevated β‐glucan concentrations can be successfully incorporated into EBC with minimal processing alterations.     

基于GPRS网络智能自来水管理系统研究与实现

在分析自来水管理现状的基础上,提出一种基于GPRS网络传输的面向各种用户的网络智能水资源管理系统。将上位管理系统分为9个模块,对其中关键模块进行详细设计,并进一步研究GPRS通讯技术,给出系统的运行界面。应用表明,该系统是一种高效率、低成本的水资源抄表系统,具有灵活的功能扩展能力,能有效地满足自来水公司和行业管理的要求。