基于软件定义网络的防火墙系统设计与实现

基于软件定义网络系统架构,提出新型防火墙安全系统。分析新型防火墙系统的架构及主要功能模块,并详述防火墙的数据流处理过程。最后利用Open Flow设备和Floodlight控制器创建了一个软件定义网络防火墙验证环境,针对不同场景进行试验,试验结果证明了防火墙的有效性和效率。     

基于MBD模型的航空发动机零件检测技术

针对当前复杂零件中异型特征位置度无法测量的问题,提出了一种基于MBD模型数字化测量技术.该方法以复杂零件的MBD模型为测量依据,通过模型理论元素与实测元素拟合计算异型特征位置度偏差,并以此为基础进行测量工艺规划、测量程序编制、测量仿真等.可大大减少在机等待时间,避免测量过程中的碰撞与测针干涉问题,解决了不规则特征位置度测量问题,实现了全程的自动测量,提高了检测效率.     

一种便携式室内空气质量快速检测仪设计

设计一种涉及室内甲醛（ HCHO）、氨（ NH3）和苯（ C6 H6）三种有害气体浓度的便携式快速检测仪。该仪器采用新型电化学传感器与基于FPGA的新型高精度信号处理电路得到对应气体的初始浓度值,并结合室内环境气压和温湿度实时监测情况,修正初始浓度值,对浓度超标气体进行声光报警。该仪器具有检测速度快、精度高和携带方便等优点,为大众家庭实时快速检测室内空气质量提供一种简单可靠的方法与手段。     

Using Memory in the Right Way to Accelerate Big Data Processing

Big data processing is becoming a standout part of data center computation. However, latest research has indicated that big data workloads cannot make full use of modern memory systems. We find that th...     

点云配准在大型曲面工件定位中的应用

针对工业生产中大尺寸薄壁工件的高精度加工需求,本文利用点云配准技术解决弱刚度及缺少定位信息等实际问题,对工件位姿进行迭代调整。最近点迭代(ICP)算法对于平坦曲面和有限点数据的精度不高,本文结合ICP算法和曲面点参数反求方法,减小了在边缘和角点的匹配误差,提高了整体匹配效果。仿真结果表明,该方法能够在保证整体性能的前提下得到较优的局部匹配精度,为解决大型曲面工件的主动寻位和自动调位问题提供了一个有效途径。     

多级半色调技术在电纸书显示优化中的应用

针对电纸书显示屏灰度等级不足的问题,提出了利用半色调图像处理技术的改进算法实现电纸书显示优化的方法.在阐述半色调技术与电子纸特点的基础上,介绍了抖动算法和误差扩散算法,通过对这两种算法进行改进提高电纸书显示的灰度级数及视觉效果.其中重点对误差扩散算法中的阈值、滤波器及扫描方式的设定进行设计,并提出一种基于误差动态检测的新的改进算法,能有效提高图像灰度级数,改善电纸书的图像显示质量.最后在电纸书系统平台上实现仿真,通过质量评价参数客观地评测了各种算法.     

空间约束混合高斯运动目标检测

目的 针对传统混合高斯模型前景检测运算量过大问题,提出一种基于空间约束的混合高斯前景检测算法。方法 通过快速初始化缩短模型的初始建立过程;采用双重背景模型机制,以自适应背景减法的前景检测结果作为混合高斯前景检测的空间约束条件,降低模型在背景区域的冗余运算;运用多策略自适应模型更新,提高前景检测的准确性。结果 在各种测试场景下,与传统混合高斯法、CodeBook、GMG、偏差均值混合高斯模型(MODGMM)等算法相比,该算法具有更好的准确率以及4倍以上的处理速度。结论 在固定相机场景下的运动目标检测中,算法能有效提高传统混合高斯法的准确性且具有极高的实时性。     

Exact and approximate flexible aggregate similarity search

Aggregate similarity search, also known as aggregate nearest-neighbor (Ann) query, finds many useful applications in spatial and multimedia databases. Given a group Q of M query objects, it retrieves from a database the objects most similar to Q, where the similarity is an aggregation (e.g., \({{\mathrm{sum}}}\), \(\max \)) of the distances between each retrieved object p and all the objects in Q. In this paper, we propose an added flexibility to the query definition, where the similarity is an aggregation over the distances between p and any subset of \(\phi M\) objects in Q for some support \(0< \phi \le 1\). We call this new definition flexible aggregate similarity search and accordingly refer to a query as a flexible aggregate nearest-neighbor ( Fann ) query. We present algorithms for answering Fann queries exactly and approximately. Our approximation algorithms are especially appealing, which are simple, highly efficient, and work well in both low and high dimensions. They also return near-optimal answers with guaranteed constant-factor approximations in any dimensions. Extensive experiments on large real and synthetic datasets from 2 to 74 dimensions have demonstrated their superior efficiency and high quality.     

Media Niche of Electronic Communication Channels in Friendship: A Meta‐Analysis

The current landscape of communication technologies is characterized by a wide variety of choices. As each medium provides different affordances, each may occupy a different niche and be used in different relationships. Drawing on the theory of the niche, we did a meta‐analysis involving 27 effect sizes from 22 independent samples to test the correlation between media selection/use and friendship closeness. Results showed that the 5 communication channels filled 2 different friendship closeness niches. Mobile phone calls and texting had stronger positive correlations with friendship closeness than instant messaging, social network sites, and online gaming. Culture, but not gender, moderated some of these correlations: Friendship closeness had a stronger positive association with SNS use and online gaming in collectivist cultures.     

Ergonomic Analysis of Mobile Cart–Assisted Stocking Activities Using Electromyography

Workers in grocery stores are exposed to numerous musculoskeletal risks that can be reduced using assistive devices while performing stocking tasks. A regional grocery store has recently deployed a mobile cart without comprehension of its ergonomic impact on workers, which this article investigates using normalized electromyography data (%MVC). This article studies not only ergonomic impact based on %MVC values but also work performance represented by a muscle force metric (MFM). The results from this study showed highest muscle groups in %MVC and MFM were the erector spinae and triceps. Interestingly, muscle activations on erector spinae were reduced when mobile cart is used. %MVC and MFM distribution for value‐added‐ and non‐value‐added subtasks were slightly different, with larger differences observed for non‐value‐added tasks. Video recordings revealed higher work performance when the mobile cart is used. In future research, the number of participants will be increased to further validate the results from this study.