2021年42卷第3期

计算机视觉一直是人工智能研究的热点方向,经过近 60 年的发展,已经在算法、技术和应用等 方面取得了巨大的进步。近十年来,以大数据、大算力为基础的深度学习进一步推动计算机视觉走向大模型时 代,但其算法适应能力仍然和人类存在较大差距。本文从视觉任务评估评测(评测数据集、评测指标、评估方 式)出发,对计算机视觉的发展进行了总结,对现存的依赖大数据学习的计算机视觉发展问题进行了梳理和分 析,从人机对抗智能评测提出了计算机视觉下一步发展方向：视觉图灵。最后对视觉图灵发展方向进行了思考 和讨论,探讨了未来研究可能的方向。     

微博用户的个性分类分析

社交网络给每个社会中的人提供了自由表达个人情感、观点、兴趣、建议等言论的平台。用户在这些平台上发表的言论、所做的行为以及用户在平台上建立的社交圈子也给数据挖掘带来了新的数据和机会。提出了一种利用用户在微博上的公开数据信息实现对该用户的MBTI个性维度进行分类分析的方法。在该方法中,基于对用户微博数据的分析,提出了能够表征用户心理和行为的文本和非文本特征,然后采用三种机器学习的分类方法—提升决策树、支持向量机和贝叶斯逻辑递归来对微博用户的个性进行分类分析。实验结果表明,通过对微博数据的挖掘可以在不同MBTI个性维度上达到75%~90%的准确率。     

统计数据汇总系统

以Delphi为开发平台,Excel为统计数据的载体,用Xml定义Excel文件的合并方式,实现了轻量级的数据汇总合并解决方案。     

利用蜜网技术检测网站攻击

通过使用蜜网技术,结合网络的组织架构,检测网站攻击,达到防御网站攻击的目的。     

渲染网格调度策略研究

针对渲染网格的特点提出了渲染网格的二个调度模型.模型一提出了在局部资源的计算结点内,采用基于用户优先级的CPU频度轮转调度方案,达到提高系统吞吐率的目的.模型二提出了适合市场机制的渲染网格调度模型,并给出了竞标的报价算法.该算法在公共网格开放软件Globus Toolkit4.0上实现,符合国际标准WSRF规范.实验结果表明本调度策略在处理渲染网格任务时性能得到了很好的体现.     

基于图像传感器网络的隧道形变监测系统研究

随着地铁建设的持续发展,隧道结构的安全性受到了广泛的关注。介绍了一种地铁隧道整体沉降的监测系统,采用安装在隧道内壁的分布式图像传感器网络对相邻断面的目标光源进行监测,并将图像数据进行采集、储存、传输、处理,数据库系统对历史数据进行融合与分析之后获得相邻断面间的相对位移,在经过坐标变换和定位基准传递后,计算出每个断面在隧道整体中的绝对位移。最终通过网络发布隧道沉降信息,建立隧道形变的预警机制。     

Using QuickBird imagery and a production efficiency model to improve crop yield estimation in the semi-arid hilly Loess Plateau,China

Crop yield is a key element in rural development and an indicator of national food security. A method that could estimate crop yield over large hilly areas would be highly desirable. Methods including high spatial resolution satellite imagery have the potential to achieve this objective. This paper describes a method of integrating QuickBird imagery with a production efficiency model (PEM) to estimate crop yield in Zhonglianchuan, a hilly area on Loess Plateau, China. In the PEM model, crop yield is a function of the photosynthetic active radiation (PAR), fraction of absorbed photosynthetically active radiation (f_APAR) and light-use efficiency (LUE). Based on the high spatial resolution QuickBird imagery, a land cover classification is used to attribute a class-specific LUE. The f_APAR is related to spectral vegetation indices (SVI), which can be derived from the satellite images. The LUE, f_APAR and incident PAR data were combined to estimate the crop yield. Farmer-reported crop yield data in 80 representative plots were used to validate the model output. The results indicated QuickBird imagery can improve the accuracy of predicted results relative to the Landsat TM image. The predicted yield approximated well with the data reported by the farmers (r² = 0.86; n = 80). The spatial distributions of crop yield derived here also offers valuable information to manage agricultural production and understand ecosystem functioning.     

基于多变量形态学特征的健康老年人认知发展预测算法

由于体积、表面积等常规形态学指标对于皮层下核团而言过于笼统,因此传统的形态特征获取手段难以检测到其表面形态的细微变化。为解决这一问题,本文提出了一种针对皮层下核团的精细特征提取算法,并将其应用到老年人认知状态预测任务上。通过表面共形参数化、表面共形表示和基于互信息的表面流配准,提取了46名被试双侧海马和杏仁核各15 000×2个顶点上的形态学特征;通过斑块选择、稀疏编码与字典学习,和最大池化的降维流程,避免了维度诅咒的同时充分保留了核团的纹理信息;最后,以树为弱学习器,采用GentleBoost算法集成了最终的强分类器做认知预测。结果显示,仅纳入海马和杏仁核两个皮层下结构的新颖特征,即可达到85%的预测准确率,为皮层下结构的精细特征发掘提供了新思路。     

Weighted stochastic response surface method considering sample weights

Conventional stochastic response surface methods (SRSM) based on polynomial chaos expansion (PCE) for uncertainty propagation treat every sample point equally during the regression process and may produce inaccurate estimations of PCE coefficients. To address this issue, a new weighted stochastic response surface method (WSRSM) that considers the sample probabilistic weights in regression is studied in this work. Techniques for determining sample probabilistic weights for three sampling approaches Gaussian Quadrature point (GQ), Monomial Cubature Rule (MCR), and Latin Hypercube Design (LHD) are developed. The advantage of the proposed method is demonstrated through mathematical and engineering examples. It is shown that for various sampling techniques WSRSM consistently achieves higher accuracy of uncertainty propagation without introducing extra computational cost compared to the conventional SRSM. Insights into the relative accuracy and efficiency of various sampling techniques in implementation are provided as well.     

KEELOQ加密算法安全性探究

文章首先简要介绍了KEELOQ加密算法的基本概念和在实践中的应用,通过分析KEELOQ加密算法的原理及特点,提出了攻击KEELOQ加密算法的具体方法。