Estimating user response rate using locality sensitive hashing in search marketing

Electronic Commerce Research - Advertising to search engine users is a primary medium of online advertising. It is the largest source of revenue for search engines. Performance-driven advertising...     

基于位置敏感哈希的网络视频重复检测

针对当前网络上存在着大量的重复或近似重复的视频问题,提出了一种基于镜头层比较和位置敏感哈希的快速准确的网络视频重复检测方法。通过视频间匹配的镜头数占查询视频总镜头数的比例来判断视频的相似性。除此之外,还利用著名的近似最近邻查找技术——LSH在镜头层来快速查找相似镜头,从而提高检测速度。通过将镜头作为检索单元,把数据库中所有视频的镜头放到一起构建一个新的数据集,将种子(查询)视频的每一个镜头作为一个查询请求,应用基于LSH的近似近邻检索方法,检索出与查询镜头相匹配的所有镜头,最后融合这些返回的结果,得到查询视频的重复或者近似重复的视频集。通过在包含12 790个视频的CC_WEB_VIDEO数据集上的实验结果表明,该方法取得了相比已有方法更好的检测性能。     

Top-Down grid位置敏感哈希k匿名隐私保护

传统位置服务匿名隐私保护方法大多在原始数据集上寻找匿名区域,很少对待隐匿区域进行筛选,会带来较高的时间消耗。事实上,匿名常常是在查询点周围进行的,通过采用Top-Down grid网格划分方法选择待匿名区域,提出了基于Top-Down grid的位置敏感哈希划分的k匿名隐私保护算法,不仅可以提高时间效率,而且与现实世界更相符,利用位置敏感哈希函数对所选位置点进行投影变换,使得划分更加合理、匿名损失率更小,匿名后的数据质量更高。理论分析和实验验证也表明所提方法的可行性和有效性。     

基于对偶字典学习的图像超分辨技术研究

提出一种基于对偶字典学习的图像超分辨方法,通过稀疏重建的方法得到重建的图像,对偶字典通过稀疏表示将低分辨图像和高分辨图像联系起来.在稀疏表示过程中,低分辨图像在低分辨字典上的稀疏表示能够很好地提高对应的高分辨图像在高分辨字典上的稀疏表示效果.将字典的学习建模为包含l1范数优化问题的双层最优化问题,采用隐微分法计算随机梯度下降的期望梯度.仿真实验结果表明,该方法能够达到和联合字典学习方法相同的速度和质量,同时,在实际应用中可以通过神经网络模型学习方法提高算法的速度.与现有的算法比较,表明了该算法的有效性.     

Locating similar names through locality sensitive hashing and graph theory

Multimedia Tools and Applications - Locality Sensitive Hashing is a known technique applied for finding similar texts and it has been applied to plagiarism detection, mirror pages identification or...     

Robust image authentication via locality sensitive hashing with core alignment

Multimedia Tools and Applications - Robust image hashing is a promising technique to represent image’s perceptual content. However, when it comes to image authentication, tradeoff between...     

超分辨率图像配准方法研究

介绍了空间域和频率域图像配准原理,在总结已有成果的基础上,对几种典型的算法进行了分析和比较,最后给出了超分辨率图像配准方法的发展方向.     

超级分布学习对象的学习服务研究

以超级分布学习对（super distributed learning object,SDLO）的寻找伙伴服务为例,对SDLO的学习服务、学习服务的通信进行了描述,并给出学习服务算法,最后利用Aglet2．0．2开发出了SDLO原型系统,对SDLO的学习服务进行了验证。SDLO的学习服务是其分布性、协作性等特性的重要体现,为知识的交流、共享与创新提供了有力支持,从而达到分布式学习和协作学习的目的。     

Using communication to reduce locality in distributed multiagent learning

Abstract. This paper attempts to bridge the fields of machine learning, robotics, and distributed AI. It discusses the use of communication in reducing the undesirable effects of locality in fully distributed multi-agent systems with multiple agents robots learning in parallel while interacting with each other. Two key problems, hidden state and credit assignment, are addressed by applying local undirected broadcast communication in a dual role: as sensing and as reinforcement. The methodology is demonstrated on two multi-robot learning experiments. The first describes learning a tightly-coupled coordination task with two robots, the second a loosely-coupled task with four robots learning social rules. Communication is used to (1) share sensory data to overcome hidden state and (2) share reinforcement to overcome the credit assignment problem between the agents and bridge the gap between local individual and global group pay-off.     

Group sparse based locality – sensitive dictionary learning for video semantic analysis

Multimedia Tools and Applications - Sparse Representation-based Classifier (SRC) and Dictionary Learning (DL), have significantly impacted greatly on the classification performance of image...     

Image super resolution by dilated dense progressive network

Image super-resolution (SR) is an interesting topic in computer vision. However, it remains challenging to achieve high-resolution image from the corresponding low-resolution version due to inherent variability, high dimensionality, and small ground targets images. In this paper, a new model based on dilated convolutional neural network is proposed to improve the image resolution. Recently, deep learning methods have led to significant improvements and completely outpace other models. However, these methods have not fully exploited all the features of the original low-resolution image, because of complex imaging conditions and the degradation process. To address this issue, we proposed an effective model based on dilated dense network operations to accelerate deep networks for image SR, which support the exponential growth of the receptive field parallel by increasing the filter size. In particular, residual network and skip connections are used for deep recovery. The experimental evaluations on several datasets prove the efficiency and stability of the proposed model. The proposed model not only achieves state-of-the-art performance but also has more efficient computation.     

基于向量量化的图像超分辨率方法

受分形编码思想启发,提出了一种新的基于向量量化的图像超分辨率方法。该方法使用学习算法来获取单幅输入图像中的高频信息和低频信息之间的对应关系,并利用此关系对输入图像的一个倍频程的空间频率内添加图像细节以获得高分辨率图像。该方法克服了传统插值方法中因过度平滑导致图像模糊和纹理保持较差的缺点,能够重现出传统插值方法不能复原出的一些高频图像细节。实验结果显示该算法在客观和主观上都比传统插值方法有更好的评价。     

用于超分辨率重建的同构过完备字典学习方法

构造合适的过完备字典是基于稀疏表示的超分辨率重建中的关键问题之一。在最大似然估计准则下,建立基于混合高斯的同构过完备字典学习模型。模型采用加权的l2范数来刻画分解残差,由分解残差设计权值矩阵,并且将同构的双字典学习问题转化为单字典的学习。采用稀疏编码和字典更新的交替迭代策略完成目标函数的求解,由内点法进行稀疏编码,采用拉格朗日对偶法完成字典更新。最后将学习得到的字典用于超分辨率重建实验,并与其他方法进行比较。实验结果验证了该模型和算法的有效性。     

高斯隶属度优化的超分辨率随机森林学习算法

随机森林学习算法是一种有效的单图像超分辨率方法,然而其决策函数是确定的二值函数,这对某些图像块的确定性划分并不是最优的选择。为提升单图像超分辨率性能,采用高斯隶属度函数构建随机森林各决策节点的决策函数,将决策函数的输出值由0和1的确定值转换到0~1之间的概率值,并在叶节点上依据数据划分路径上各决策节点概率的乘积进行预测,依据最小经验冒险准则学习决策参数,使随机森林能更好学习不同的样本数据。实验结果表明,与随机森林学习等目前主流单图像超分辨率方法相比,该方法可以提升超分辨率图像的峰值信噪比,同时运算效率与传统随机森林学习算法相当。     

Image retrieval using nonlinear manifold embedding

The huge number of images on the Web gives rise to the content-based image retrieval (CBIR) as the text-based search techniques cannot cater to the needs of precisely retrieving Web images. However, CBIR comes with a fundamental flaw: the semantic gap between high-level semantic concepts and low-level visual features. Consequently, relevance feedback is introduced into CBIR to learn the subjective needs of users. However, in practical applications the limited number of user feedbacks is usually overwhelmed by the large number of dimensionalities of the visual feature space. To address this issue, a novel semi-supervised learning method for dimensionality reduction, namely kernel maximum margin projection (KMMP) is proposed in this paper based on our previous work of maximum margin projection (MMP). Unlike traditional dimensionality reduction algorithms such as principal component analysis (PCA) and linear discriminant analysis (LDA), which only see the global Euclidean structure, KMMP is designed for discovering the local manifold structure. After projecting the images into a lower dimensional subspace, KMMP significantly improves the performance of image retrieval. The experimental results on Corel image database demonstrate the effectiveness of our proposed nonlinear algorithm.     

基于自适应规整化方法的图像超分辨率重建

以Gauss-Gibbs随机场模型为图像的先验概率模型,运用自适应规整化的最大后验概率(MAP)方法进行图像超分辨率重建.通过对先验概率分布参数的估计,对图像超分辨率重建求解进行自适应规整化,从而提高重建图像的质量.实验结果表明,该算法能较好地再现图像的各种边缘信息,重建的高分辨率图像在峰值信噪比和视觉效果方面都得到明显提高.     

基于深度学习的单图像超分辨率重建研究综述

为深入了解基于深度学习的单图像超分辨率重建（SISR）的发展,把握当前研究的热点和方向,针对现有基于深度学习的单图像超分辨率重建模型进行了梳理。介绍了相关深度学习算法和基于深度学习的模型以及评价指标,并通过实验对比分析现有模型的性能,其目的在于从本质上了解基于深度学习的单图像超分辨率重建模型的优势;对单图像超分辨率重建的关键问题进行了总结,并对未来的发展趋势进行了展望。     

基于加权随机森林的图像超分辨率算法研究

针对目前图像超分辨率重建效果欠佳的问题,提出一种基于加权随机森林的图像超分辨率重建算法.利用随机森林对图像块的特征进行聚类,并引入岭回归模型建立每类叶子结点中高、低分辨率图像块的映射关系,重建时根据测试低分辨率图像块所属的类别以及在每类叶子结点中的K近邻近似拟合误差,进行加权预测获得高分辨率图像块.将图像的非局部自相似性与迭代反投影算法相结合对预测的高分辨率图像进行后处理以提高重建质量.实验结果表明,所提出算法可以有效提高峰值信噪比,具有较好的可视效果.