A study on a vision sensor system for tracking the I-Butt weld joints

In this study, a visual sensor system for weld seam tracking the I-butt weld joints in GMA welding was constructed. The sensor system consists of a CCD camera, a diode laser with a cylindrical lens and a band-pass-filter to overcome the degrading of image due to spatters and arc light. In order to obtain the enhanced image, quantitative relationship between laser intensity and iris opening was investigated. Throughout the repeated experiments, the shutter speed was set at 1/1000 second for minimizing the effect of spatters on the image, and therefore the image without the spatter traces could be obtained. Region of interest was defined from the entire image and gray level of the searched laser stripe was compared to that of weld line. The differences between these gray levels lead to spot the position of weld joint using central difference method. The results showed that, as long as weld line is within ±15° from the longitudinal straight line, the system constructed in this study could track the weld line successfully. Since the processing time is no longer than 0.05 sec, it is expected that the developed method could be adopted to high speed welding such as laser welding.     

蓝牙资格认证要点

蓝牙资格认证的核心规范带来了物理层、链路层和同步适配层的新测试要求。介绍了蓝牙资格认证的四个要点,包括蓝牙资格认证流程、蓝牙技术联盟会员须知、蓝牙资格认证版本、蓝牙组网技术认证与测试规范,旨在为有蓝牙认证需求的企业提供帮助。     

基于贝叶斯后验概率和非合作博弈的推荐算法

针对传统协同过滤推荐算法推荐精度较低等问题,提出一种基于贝叶斯后验概率预测和非合作博弈的个性化推荐算法。采用文件主题模型求取用户与其参加过的所有社交活动的主题分布,利用隐含主题概率分布表征用户兴趣度,根据信任传递机制求取用户的直接信任和间接信任,形成用户间的信任度;将用户的兴趣度和信任度等隐式特征赋予合理的先验分布,利用贝叶斯后验概率预测隐式特征后的显式反馈;依据显式反馈将推荐结果转化为非合作博弈中用户效益最大化的纳什均衡求解。仿真对比实验表明,与其他三种推荐算法相比该算法的查准率至少提高了3.13%,查全率至少提高了2.62%。     

基于距离类别的多源兴趣点融合算法

为了更好地实现多源兴趣点（POI）数据的有效集成与精确融合,提出了一种结合空间与非空间属性的距离类别的兴趣点融合算法（MNMDC）。首先,对空间属性,通过标准化权重算法计算待融合对象的空间相似度得到融合集;其次,利用非空间Jaro-Winkle算法对融合集中类别一致的对象使用低阈值排除,对类别不一致的使用高阈值排除;最后,使用距离约束、类别一致约束和高阈值的非空间Jaro-Winkle算法找出空间算法遗漏的可融合对象。实验结果表明,该方法平均准确率达到93.3%,与空间和非空间算法（COM-NWT）及格网化纠正方法相比,在7组不同重合度的数据下MNMDC方法的平均准确率提高2.7和1.6个百分点、平均召回率提高2.3和1.4个百分点。MNMDC在实际融合过程中能更精确地融合POI数据。     

Visual Attention for Rendered 3D Shapes

Understanding the attentional behavior of the human visual system when visualizing a rendered 3D shape is of great importance for many computer graphics applications. Eye tracking remains the only solution to explore this complex cognitive mechanism. Unfortunately, despite the large number of studies dedicated to images and videos, only a few eye tracking experiments have been conducted using 3D shapes. Thus, potential factors that may influence the human gaze in the specific setting of 3D rendering, are still to be understood. In this work, we conduct two eye‐tracking experiments involving 3D shapes, with both static and time‐varying camera positions. We propose a method for mapping eye fixations (i.e., where humans gaze) onto the 3D shapes with the aim to produce a benchmark of 3D meshes with fixation density maps, which is publicly available. First, the collected data is used to study the influence of shape, camera position, material and illumination on visual attention. We find that material and lighting have a significant influence on attention, as well as the camera path in the case of dynamic scenes. Then, we compare the performance of four representative state‐of‐the‐art mesh saliency models in predicting ground‐truth fixations using two different metrics. We show that, even combined with a center‐bias model, the performance of 3D saliency algorithms remains poor at predicting human fixations. To explain their weaknesses, we provide a qualitative analysis of the main factors that attract human attention. We finally provide a comparison of human‐eye fixations and Schelling points and show that their correlation is weak.     

论我国公益诉讼的现状及构建

目前,“公益诉讼”在我国并不是一个法律概念,我国尚未建立起公益诉讼的相关制度,使得公益诉讼还处在摸索阶段,在具体的司法实践中不可避免地遇到了许多现实的问题。本文从公共利益及公益诉讼的内涵入手,在分析我国公益诉讼现状的基础上,就我国公益诉讼的构建提出自己的见解。     

基层政府与失地农民利益关系研究

随着我国城市化、工业化的快速发展,城市及工业用地的增加,在土地征用的过程中产生了大量失地农民。失地农民的生存和发展成为构建社会主义和谐社会过程中必须要解决的问题。本文深入剖析了基层政府和失地农民在征地过程中产生的种种矛盾及利益互动关系,并提出几点思考。     

Dutch Personal Income Tax Reform 2001: An Exceptional Position for Owner-occupied Housing

This paper examines how personal income taxation has changed across countries and whether and how this has affected the taxation of owner-occupied dwellings. It presents a partial analysis as it focuses on imputed rent taxation and the mortgage interest deduction. Furthermore, the paper places housing taxation in a wider context by describing different benchmarks which could be used to assess the taxation of owner-occupied housing in different types of personal income tax. These international and theoretical points-of-departure are used to evaluate the taxation of owner-occupied housing in the Netherlands. The paper concludes that all along political arguments have conquered theoretical premises to the advantage of the owner occupier in comparison to the private landlord. It also concludes that the theoretical base in 2001 has become so weak that owner-occupied housing is in an exceptional position in comparison with other private wealth thus becoming an easy victim for future tax savings.     

Cooperative detection and protection for Interest flooding attacks in named data networking

Named data networking (NDN) is a new emerging architecture for future network, which may be a substitute of the current TCP/IP‐based network, for the content‐oriented data request mode becoming the future trend of development. The security of NDN has attracted much attention, as an implementation of next‐generation Internet architecture. Although NDN is immune to most current attack, it cannot resist the distributed denial of service like attack – Interest flooding attack (IFA) – effectively. IFA takes advantages of the forwarding mechanism of NDN, flooding a large number of malicious Interest packets at quite a high rate, and exploits the network resources, which may cause the paralysis of the network. Taking into account the severity of the destruction, we propose an algorithm to counter such new type of attack. We analyze three properties of IFA, and use them to judge and filter Interest packets. Vector space model and Markov model are used in our method to realize a cooperative detection. Meanwhile, we present the retransmission forwarding mechanism to ensure legitimate user request. The ndnSIM module of ns3 is used for the corresponding simulation, and results of the simulation will be given to show the effectiveness of our algorithm. Copyright © 2014 John Wiley & Sons, Ltd.     

基于曲线聚类的动态PET影像感兴趣区域提取新方法

针对目前动态正电子发射断层扫描(PET)影像的感兴趣区域(ROI)提取的聚类方法忽略了时间放射性曲线(TAC)的时间序列特征,提出一种基于曲线聚类的ROI提取方法。首先用K-均值(K-Means)聚类去除背景得到心脏的位置,然后对心脏进行曲线聚类提取出心肌,最后根据像素点的空间位置关系提取血池。将该方法应用于14只小鼠的PET影像ROI勾画,实验结果表明,与K-Means和混合型的聚类方法HCM相比,该方法能够更准确地提取出14只小鼠的血池,且具有更高的精确度和稳定性。