Model incremental updating enhances the initial model by analysing discrepancy parts of the system to improve the model's adaptability for new scenarios. These discrepancy components originate from the deviation between the increasing business process operational state and the outdated original planning model. Considerable domain-specific knowledge is required to determine the threshold points for selecting appropriate activities, but process analysts rarely know each scenario's domain knowledge. Moreover, most analytical processes only focussed on the control flow level. Aiming at these issues, this paper proposes a Hybrid Behavioural and Resource Trusted intervals Updating algorithm (BI&RI Updating) for model enhancement based on control level and resource level of online event streams. First, analyse the reference model to construct multi-perspective trusted interval constraints in the offline stage. From a control-flow perspective, the behavioural relationships between activities are researched using a deep clustering approach. Moreover, from a data-flow standpoint, resource co-occurrence relationships are analysed based on association rules. Next, the incremental update algorithm in online scenarios is proposed to update the model by filtering the event streams and iteratively optimising the trusted intervals. Finally, the proposed algorithm is implemented based on the PM4PY framework and evaluated using real logs with both outcome model quality and execution efficiency. The results show that the algorithm can execute quickly and improve the quality of the model even in a non-ideal state where the logs contain noise.
Process discovery usually analyses frequent behaviour in event logs to gain an intuitive understanding of processes. However, there are some effective infrequent behaviours that help to improve business processes in real life. Most existing studies either ignore them or treat them as harmful behaviours. To distinguish effective infrequent sequences from noisy activities, this paper proposes an algorithm to analyse the distribution states of activities and the strong transfer relationships between behaviours based on maximum probability paths. The algorithm divides episodic traces into two categories: harmful and useful episodes, namely noisy activities and effective sequences. First, using conditional probability entropy, the infrequent logs are pre-processed to remove individual noisy activities that are extremely irregularly distributed in the traces. Effective sequences are then extracted from the logs based on the state transfer information of the activities. The algorithm is based on a PM4Py implementation and is validated using synthetic and real logs. From the results, the algorithm not only preserves the key structure of the model and reduces noise activity, but also improves the quality of the model.
Anomalous behavior detection in business processes inspects abnormal situations, such as errors and missing values in system execution records, to facilitate safe system operation. Since anomaly information hinders the insightful investigation of event logs, many approaches have contributed to anomaly detection in either the business process domain or the data mining domain. However, most of them ignore the impact brought by the interaction between activities and their related attributes. Based on this, a method is constructed to integrate the consistency degree of multi-perspective log features and use it in an isolation forest model for anomaly detection. First, a reference model is captured from the event logs using process discovery. After that, the similarity between behaviors is analyzed based on the neighborhood distance between the logs and the reference model, and the data flow similarity is measured based on the matching relationship of the process activity attributes. Then, the integration consistency measure is constructed. Based on this, the composite log feature vectors are produced by combining the activity sequences and attribute sequences in the event logs and are fed to the isolation forest model for training. Subsequently, anomaly scores are calculated and anomalous behavior is determined based on different threshold-setting strategies. Finally, the proposed algorithm is implemented using the Scikit-learn framework and evaluated in real logs regarding anomalous behavior recognition rate and model quality improvement. The experimental results show that the algorithm can detect abnormal behaviors in event logs and improve the model quality.
Business process anomalous behavior detection reveals unexpected cases from event logs to ensure the trusted operation of information systems. Anomaly behavior is mainly identified through a log-to-model alignment analysis or numerical outlier detection. However, both approaches ignore the influence of probability distributions or activity relationships in process activities. Based on this concern, this paper incorporates the behavioral relationships characterized by the process model and the joint probability distribution of nodes related to suspected anomalous behaviors. Moreover, a Petri Net-Based Bayesian Network (PN-BBN) is proposed to detect anomalous behaviors based on the probabilistic inference of behavioral contexts. First, the process model is filtered based on the process structure of the process activities to identify the key regions where the suspected anomalous behaviors are located. Then, the behavioral profile of the activity is used to prune it to position the ineluctable paths that trigger these activities. Further, the model is used as the architecture for parameter learning to construct the PN-BBN. Based on this, anomaly scores are inferred based on the joint probabilities of activities related to suspected anomalous behaviors for anomaly detection under the constraints of control flow and probability distributions. Finally, PN-BBN is implemented based on the open-source frameworks PM4PY and PMGPY and evaluated from multiple metrics with synthetic and real process data. The experimental results demonstrate that PN-BBN effectively identifies anomalous process behaviors and improves the reliability of information systems.
为了有效分析事件流之间特定的行为关系并将其融入预测过程,提出一种基于事件流行为向量的在线事件流协同过滤推荐算法来预测下一个事件.首先分析事件流之间的结构相似性和行为相似性,以确定事件流的行为轮廓关系,在此基础上捕获事件流的行为依赖关系,将事件流构建为行为向量;然后调整传统的协同过滤推荐算法以分析在线事件流,对下一个事件流进行有效预测;最后,在Pm4py框架中实现相关算法,并在合成日志和真实日志中进行仿真预测.实验结果表明,行为向量能够体现事件流的行为关系,并提高预测的有效性.
Incremental mining improves the quality of process mining by analyzing the differences between event logs and a reference model to obtain valuable information to update the reference model. Existing incremental mining methods focus on offline logs by setting thresholds for analysis, which limits process mining efforts by the domain knowledge, log completeness, and business completion time. Aiming at these problems, a real-time incremental mining algorithm based on the trusted behavior interval is proposed to analyze online event streams for updating the reference model. First, a clustering technique to analyze an existing reference model selects the core structure of the model and calculates the trusted behavior interval. Then, the behavioral and structural relationships between the online event streams and the reference model are analyzed to obtain a valid candidate set. Based on this set, an incremental update algorithm is proposed to optimize the model structure to achieve an online dynamic update of the reference model. The proposed algorithm is implemented in PM4PY and Scikit-learn frameworks; a reasonable number of clusters is determined using the elbow method and validated with artificial and real data. Experimental results show that the algorithm improves the efficiency of incremental mining and enhances the quality of the model with both complete and incomplete data.
低频行为的挖掘是业务流程管理的重要内容之一,区分有效低频和噪音在业务流程优化中显得尤为重要.已有挖掘方法多是从数据属性研究低频行为,较少根据不同模块间的行为属性来分析低频行为,由此提出基于Petri网的业务流程低频行为的挖掘与优化方法.首先,通过用流程树切的直接流图表示日志的行为关系,并与初始模型做匹配,发现所有的低频序列;然后,计算日志与模型的行为距离向量,基于行为紧密度区分有效低频日志和噪音日志,优化事件日志;其次,利用不包含噪音序列的事件日志通过融合交互模块网与特征网,挖掘得到一个优化的业务流程模型;最后,通过具体的实例分析和仿真实验验证了该方法的有效性.