Hierarchical visual event pattern mining and its applications

In this paper, we propose a hierarchical visual event pattern mining approach and utilize the patterns to address the key problems in video mining and understanding field. We classify events into primitive events (PEs) and compound events (CEs), where PEs are the units of CEs, and CEs serve as smooth priors and rules for PEs. We first propose a tensor-based video representation and Joint Matrix Factorization (JMF) for unsupervised primitive event categorization. Then we apply frequent pattern mining techniques to discover compound event pattern structures. After that, we utilize the two kinds of event patterns to address the applications of event recognition and anomaly detection. First we extend the Sequential Monte Carlo (SMC) method to recognition of live, sequential visual events. To accomplish this task we present a scheme that alternatively recognizes primitive and compound events in one framework. Then, we categorize the anomalies into abnormal events (never seen events) and abnormal contexts (rule breakers), and the two kinds of anomalies are detected simultaneously by embedding a deviation criterion into the SMC framework. Extensive experiments have been conducted which demonstrate that the proposed approach is effective as compared to other major approaches.     

Semantic trajectory-based high utility item recommendation system

The topic on recommendation systems for mobile users has attracted a lot of attentions in recent years. However, most of the existing recommendation techniques were developed based only on geographic features of mobile users’ trajectories. In this paper, we propose a novel approach for recommending items for mobile users based on both the geographic and semantic features of users’ trajectories. The core idea of our recommendation system is based on a novel cluster-based location prediction strategy, namely TrajUtiRec, to improve items recommendation model. Our proposed cluster-based location prediction strategy evaluates the next location of a mobile user based on the frequent behaviors of similar users in the same cluster determined by analyzing users’ common behaviors in semantic trajectories. For each location, high utility itemset mining algorithm is performed for discovering high utility itemset. Accordingly, we can recommend the high utility itemset which is related to the location the user might visit. Through a comprehensive evaluation by experiments, our proposal is shown to deliver excellent performance.     

Projection-based partial periodic pattern mining for event sequences

Partial periodic pattern mining is one of the important issues in the field of data mining due to its practical applications. A partial periodic pattern consists of some periodic and non-periodic events in a specific period length, and is repeated with high frequency in an event sequence. In the past, a max-subpattern hit set algorithm was developed to discover partial periodic patterns, but its drawback is spending a large amount of time in calculating frequency counts from the redundant candidate nodes. In this study, we thus adopt an efficient encoding strategy to speed up the efficiency of processing period segments in an event sequence, and combined with the projection method to quickly find the partial periodic patterns in the recursive process. Finally, the experimental results show the superior performance of the proposed approach.     

基于本体的监控视频语义事件探测*

为了探测视频高层复杂事件,架构了一个视频事件分析框架,采用本体和Petri网进行推理从而获取复合事件;运用视频语义本体标注算法分析低层视频语义,在高层构建一个视频事件分析本体,将低层本体映射到事件分析本体表示高层视频事件;通过本体和扩展Petri网结合的方法对监控视频中的事件进行图形化异步事件推理;最后用semantic Web rule language(SWRL)规则表示视频监控事件的探测。实验证明,提出的方法比基于模式识别的事件探测方法更加有效。     

Semantic analysis of role mining results and shadowed roles detection

The use of role engineering has grown in importance with the expansion of highly abstracted access control frameworks in organizations. In particular, the use of role mining techniques for the discovery of roles from previously deployed authorizations has facilitated the configuration of such frameworks. However, the literature lacks from a clear basis for appraising and leveraging the learning outcomes of the role mining process. In this paper, we provide such a formal basis. We compare sets of roles by projecting roles from one set into the other set. This approach is useful to measure how comparable the two configurations of roles are, and to interpret each role. We formally define the problem of comparing sets of roles, and prove that the problem is NP-complete. Then, we propose an algorithm to map the inherent relationship between the sets based on Boolean expressions. We demonstrate the correctness and completeness of our solution, and investigate some further issues that may benefit from our approach, such as detection of unhandled perturbations or source misconfiguration. In particular, we emphasize that the presence of shadowed roles in the role configuration increases the time complexity of sets of roles comparison. We provide a definition of the shadowed roles problem and propose a solution that detects different cases of role shadowing.     

Malicious sequential pattern mining for automatic malware detection

Due to its damage to Internet security, malware (e.g., virus, worm, trojan) and its detection has caught the attention of both anti-malware industry and researchers for decades. To protect legitimate users from the attacks, the most significant line of defense against malware is anti-malware software products, which mainly use signature-based method for detection. However, this method fails to recognize new, unseen malicious executables. To solve this problem, in this paper, based on the instruction sequences extracted from the file sample set, we propose an effective sequence mining algorithm to discover malicious sequential patterns, and then All-Nearest-Neighbor (ANN) classifier is constructed for malware detection based on the discovered patterns. The developed data mining framework composed of the proposed sequential pattern mining method and ANN classifier can well characterize the malicious patterns from the collected file sample set to effectively detect newly unseen malware samples. A comprehensive experimental study on a real data collection is performed to evaluate our detection framework. Promising experimental results show that our framework outperforms other alternate data mining based detection methods in identifying new malicious executables.     

基于相邻事件概率统计的流程挖掘方法

为了提高流程挖掘的准确性和抗噪性,针对目前流程挖掘的基本结构有限、抗噪能力弱、计算耗时长等问题,提出了一种基于相邻事件概率统计的流程挖掘方法。该方法基于挖掘规则,仅需做一次日志遍历和矩阵的简单运算,就可生成挖掘的流程模型。与α算法和启发式算法的实验验证结果表明,该算法不仅能够挖掘顺序、选择、并行、短循环、递归等流程基本结构,而且具有计算复杂度低、抗噪能力强等优势。     

基于社交媒体文本挖掘的个人事件检测方法

用户的社交媒体中蕴含着他们过去的个人经历和潜在的生活规律,研究其规律对预测用户未来的行为以及对用户进行个性化推荐有很大的价值。通过收集微博数据,定义了11种类型的事件,并提出了一个三阶段的Pipeline的系统,利用BERT预训练模型,分别在三个阶段使用BERT+BiLSTM+Attention、BERT+FullConnect、BERT+BiLSTM+CRF方法进行个人事件检测。从微博文本中抽取出该文本是否包含定义的事件、包含的事件类型、每种事件包含的元素等信息,具体元素为Subject（事件主语）、Object（事件元素）、Time（事件发生时间）、Place（事件发生的地点）和Tense（事件发生的时态）,从而探究用户个人时间轴上的事件变化规律来预测个人事件。在收集的真实用户微博数据集上进行实验,并与逻辑回归、朴素贝叶斯、随机森林、决策树等分类算法进行对比分析。实验结果表明,三个阶段中的BERT+BiLSTM+Attention、BERT+FullConnect和BERT+BiLSTM+CRF方法均取得了最高的F1值,验证了所提方法的有效性。最后根据所提方法抽取出的事件和其中的时间信息可视化地构建了用户的个人事件时间轴。     

Video data mining: semantic indexing and event detection from the association perspective

Advances in the media and entertainment industries, including streaming audio and digital TV, present new challenges for managing and accessing large audio-visual collections. Current content management systems support retrieval using low-level features, such as motion, color, and texture. However, low-level features often have little meaning for naive users, who much prefer to identify content using high-level semantics or concepts. This creates a gap between systems and their users that must be bridged for these systems to be used effectively. To this end, in this paper, we first present a knowledge-based video indexing and content management framework for domain specific videos (using basketball video as an example). We will provide a solution to explore video knowledge by mining associations from video data. The explicit definitions and evaluation measures (e.g., temporal support and confidence) for video associations are proposed by integrating the distinct feature of video data. Our approach uses video processing techniques to find visual and audio cues (e.g., court field, camera motion activities, and applause), introduces multilevel sequential association mining to explore associations among the audio and visual cues, classifies the associations by assigning each of them with a class label, and uses their appearances in the video to construct video indices. Our experimental results demonstrate the performance of the proposed approach.     

Community detection in social networks using user frequent pattern mining

Recently, social networking sites are offering a rich resource of heterogeneous data. The analysis of such data can lead to the discovery of unknown information and relations in these networks. The detection of communities including ‘similar’ nodes is a challenging topic in the analysis of social network data, and it has been widely studied in the social networking community in the context of underlying graph structure. Online social networks, in addition to having graph structures, include effective user information within networks. Using this information leads to enhance quality of community discovery. In this study, a method of community discovery is provided. Besides communication among nodes to improve the quality of the discovered communities, content information is used as well. This is a new approach based on frequent patterns and the actions of users on networks, particularly social networking sites where users carry out their preferred activities. The main contributions of proposed method are twofold: First, based on the interests and activities of users on networks, some small communities of similar users are discovered, and then by using social relations, the discovered communities are extended. The F-measure is used to evaluate the results of two real-world datasets (Blogcatalog and Flickr), demonstrating that the proposed method principals to improve the community detection quality.     

基于频繁模式的离群点挖掘在入侵检测中的应用

针对网络安全数据高维度的特征,对传统离群点检测不能有效发现的网络数据中入侵行为细节进行检测。提出一种基于频繁模式的算法,通过检测数据项的频繁模式和关联规则,剥离数据流中或安全日志数据中的噪声和异常点,计算安全数据的加权频繁离群因子,精确定位离群点,最后从中自动筛选出异常属性。实验证明,该方法在较好的空间复杂性与时间复杂性下,能有效地发现在高维安全数据中异常的属性。     

Semantic domains of timed event structures

In the paper, timed extensions of various classes of event structures and marked Scott domains are studied, categories of these models are constructed, and their properties are examined. In addition, based on category-theoretic methods, relationship between the timed structures and marked Scott domains is established.     

On integrating event definition and event detection

We develop, in this paper, a representation of time and events that supports a range of reasoning tasks such as monitoring and detection of event patterns which may facilitate the explanation of root cause(s) of faults. We shall compare two approaches to event definition: the active database approach in which events are defined in terms of the conditions for their detection at an instant, and the knowledge representation approach in which events are defined in terms of the conditions for their occurrence over an interval. We shall show the shortcomings of the former definition and employ a three-valued temporal first order nonmonotonic logic, extended with events, in order to integrate both definitions.     

基于数据挖掘的入侵检测系统智能结构模型

为了提高对拒绝服务攻击、内存溢出攻击、端口扫描攻击和网络非法入侵等发现的有效性以及对海量的安全审计数据能进行智能化处理,采用数据挖掘的方法从大量的信息中提取有威胁的、隐蔽的入侵行为及其模式.将数据挖掘的聚类分析方法与入侵检测系统相结合,提出了一种入侵检测系统的智能结构模型.实验表明,它能够有效地从海量的网络数据中进行聚类划分,找到相关的入侵数据,从而提高对各种攻击类型网络入侵检测的效率.     

边界显著性与模式挖掘

针对目标在图像边界上带来的检测误差,提出了边界显著性算法。首先在多尺度下对图像进行超像素分割,计算边界差异,估计其边界显著性。而后对所有超像素进行模式挖掘,得到显著性种子,并与边界显著性相结合。最后通过显著性传播得到最终显著图。在三个公开的测试数据集上将本文提出算法与其他18种主流的现有算法进行对比。大量实验结果表明,所提出的算法在不同数据集上都优于目前主流算法。     

Sequential pattern mining of geo-tagged photos with an arbitrary regions-of-interest detection method

Geo-tagged photos leave trails of movement that form trajectories. Regions-of-interest detection identifies interesting hot spots where many trajectories visit and large geo-tagged photos are uploaded. Extraction of exact shapes of regions-of-interest is a key step to understanding these trajectories and mining sequential trajectory patterns. This article introduces an efficient and effective grid-based regions-of-interest detection method that is linear to the number of grid cells, and is able to detect arbitrary shapes of regions-of-interest. The proposed algorithm is combined with sequential pattern mining to reveal sequential trajectory patterns. Experimental results reveal quality regions-of-interest and promising sequential trajectory patterns that demonstrate the benefits of our algorithm.     

From sequential pattern mining to structured pattern mining: A pattern-growth approach

Sequential pattern mining is an important data mining problem with broad applications. However,it is also a challenging problem since the mining may have to generate or examine a combinatorially explosivenumber of intermediate subsequences. Recent studies have developed two major classes of sequential patternmining methods: (1) a candidate generation-and-test approach, represented by (i) GSP, a horizontal format-basedsequential pattern mining method, and (ii) SPADE, a vertical format-based method; and (2) a pattern-growthmethod, represented by PrefixSpan and its further extensions, such as gSpan for mining structured patterns. In this study, we perform a systematic introduction and presentation of the pattern-growth methodologyand study its principles and extensions. We first introduce two interesting pattern-growth algorithms, FreeSpanand PrefixSpan, for efficient sequential pattern mining. Then we introduce gSpan for mining structured patternsusing the same methodology. Their relative performance in l     

Closed inter-sequence pattern mining

Inter-sequence pattern mining can find associations across several sequences in a sequence database, which can discover both a sequential pattern within a transaction and sequential patterns across several different transactions. However, inter-sequence pattern mining algorithms usually generate a large number of recurrent frequent patterns. We have observed mining closed inter-sequence patterns instead of frequent ones can lead to a more compact yet complete result set. Therefore, in this paper, we propose a model of closed inter-sequence pattern mining and an efficient algorithm called CISP-Miner for mining such patterns, which enumerates closed inter-sequence patterns recursively along a search tree in a depth-first search manner. In addition, several effective pruning strategies and closure checking schemes are designed to reduce the search space and thus accelerate the algorithm. Our experiment results demonstrate that the proposed CISP-Miner algorithm is very efficient and outperforms a compared EISP-Miner algorithm in most cases.     

View-invariant motion trajectory-based activity classification and recognition

Motion trajectories provide rich spatio-temporal information about an object's activity. The trajectory information can be obtained using a tracking algorithm on data streams available from a range of devices including motion sensors, video cameras, haptic devices, etc. Developing view-invariant activity recognition algorithms based on this high dimensional cue is an extremely challenging task. This paper presents efficient activity recognition algorithms using novel view-invariant representation of trajectories. Towards this end, we derive two Affine-invariant representations for motion trajectories based on curvature scale space (CSS) and centroid distance function (CDF). The properties of these schemes facilitate the design of efficient recognition algorithms based on hidden Markov models (HMMs). In the CSS-based representation, maxima of curvature zero crossings at increasing levels of smoothness are extracted to mark the location and extent of concavities in the curvature. The sequences of these CSS maxima are then modeled by continuous density (HMMs). For the case of CDF, we first segment the trajectory into subtrajectories using CDF-based representation. These subtrajectories are then represented by their Principal Component Analysis (PCA) coefficients. The sequences of these PCA coefficients from subtrajectories are then modeled by continuous density hidden Markov models (HMMs). Different classes of object motions are modeled by one Continuous HMM per class where state PDFs are represented by GMMs. Experiments using a database of around 1750 complex trajectories (obtained from UCI-KDD data archives) subdivided into five different classes are reported.