关键语义区域链提取的视频人体行为识别

目的 视频中的人体行为识别技术对智能安防、人机协作和助老助残等领域的智能化起着积极的促进作用,具有广泛的应用前景。但是,现有的识别方法在人体行为时空特征的有效利用方面仍存在问题,识别准确率仍有待提高。为此,本文提出一种在空间域使用深度学习网络提取人体行为关键语义信息并在时间域串联分析从而准确识别视频中人体行为的方法。方法 根据视频图像内容,剔除人体行为重复及冗余信息,提取最能表达人体行为变化的关键帧。设计并构造深度学习网络,对图像语义信息进行分析,提取表达重要语义信息的图像关键语义区域,有效描述人体行为的空间信息。使用孪生神经网络计算视频帧间关键语义区域的相关性,将语义信息相似的区域串联为关键语义区域链,将关键语义区域链的深度学习特征计算并融合为表达视频中人体行为的特征,训练分类器实现人体行为识别。结果 使用具有挑战性的人体行为识别数据集UCF （University of Central Florida）50对本文方法进行验证,得到的人体行为识别准确率为94.3%,与现有方法相比有显著提高。有效性验证实验表明,本文提出的视频中关键语义区域计算和帧间关键语义区域相关性计算方法能够有效提高人体行为识别的准确率。结论 实验结果表明,本文提出的人体行为识别方法能够有效利用视频中人体行为的时空信息,显著提高人体行为识别准确率。     

An on-line SAX and HMM-based anomaly detection and visualization tool for early disturbance discovery in a dynamic industrial process

In order to achieve an optimum and successful operation of an industrial process, it is important firstly to detect upsets, equipment malfunctions or other abnormal events as early as possible and secondly to identify and remove the cause of those events. Univariate and multivariate statistical process control methods have been widely applied in process industries for early fault detection and localization.The primary objective of the proposed research is the design of an anomaly detection and visualization tool that is able to present to the shift operator – and to the various levels of plant operation and company management – an early, global, accurate and consolidated presentation of the operation of major subgroups or of the whole plant, aided by a graphical form.Piecewise Aggregate Approximation (PAA) and Symbolic Aggregate Approximation (SAX) are considered as two of the most popular representations for time series data mining, including clustering, classification, pattern discovery and visualization in time series datasets. However SAX is preferred since it is able to transform a time series into a set of discrete symbols, e.g. into alphabet letters, being thus far more appropriate for a graphical representation of the corresponding information, especially for the shift operator. The methods are applied on individual time records of each process variable, as well as on entire groups of time records of process variables in combination with Hidden Markov Models. In this way, the proposed visualization tool is not only associated with a process defect, but it allows also identifying which specific abnormal situation occurred and if this has also occurred in the past. Case studies based on the benchmark Tennessee Eastman process demonstrate the effectiveness of the proposed approach. The results indicate that the proposed visualization tool captures meaningful information hidden in the observations and shows superior monitoring performance.     

A Novel Similarity Measure to Induce Semantic Classes and Its Application for Language Model Adaptation in a Dialogue System

In this paper,we propose a novel co-occurrence probabilities based similarity measure for inducing semantic classes.Clustering with the new similarity measure outperforms the widely used distance based on Kullback-Leibler divergence in precision,recall and F1 evaluation.In our experiments,we induced semantic classes from unannotated in-domain corpus and then used the induced classes and structures to generate large in-domain corpus which was then used for language model adaptation.Character recognition rate was improved from 85.2% to 91%.We imply a new measure to solve the lack of domain data problem by first induction then generation for a dialogue system.     

A review of the Expectation Maximization algorithm in data-driven process identification

The Expectation Maximization (EM) algorithm has been widely used for parameter estimation in data-driven process identification. EM is an algorithm for maximum likelihood estimation of parameters and ensures convergence of the likelihood function. In presence of missing variables and in ill conditioned problems, EM algorithm greatly assists the design of more robust identification algorithms. Such situations frequently occur in industrial environments. Missing observations due to sensor malfunctions, multiple process operating conditions and unknown time delay information are some of the examples that can resort to the EM algorithm. In this article, a review on applications of the EM algorithm to address such issues is provided. Future applications of EM algorithm as well as some open problems are also provided.