## 2 Literature Review
### Process Mining Applications in Architecture, Engineering, and Construction  
There have been studies to integrate process mining and simulation modeling for construction engineering and management. One paper proposed an approach to discovering an activity cycle diagram (ACD) from the activity log data of the construction machinery [10]. This study introduced a refined alpha algorithm to discover the underlying behavior of heavy construction equipment from the ordered and recorded sequential activities. Eventually, it demonstrated the successful mining of the workflow process of earthmoving operations represented by an ACD.  
In another effort, process mining techniques were applied in the Architecture, Engineering, Construction, and Facility Management industry (AECFM) [11]. As the AECFM industry is utilizing and adapting IT systems within the lifecycle of projects, this creates the possibility to use process mining to gather important insights into the processes of construction projects. Three case studies were performed in the design-, build-, and operational phases. The findings of the study provide useful insight and potential applications of process mining in the AECFM industry.  
Process mining has been applied to data-driven process discovery in the cost estimation process in construction [12]. Data were collected from a software-supported cost estimation platform for three different construction projects. Analysis was carried out from the control flow, case, and organizational perspective. An automated script was developed to improve the quality of the logged data to meet the process mining requirements. The findings show that the proposed approach can perform comparative analyses across projects and companies to make process mining methods a useful application in the Architecture, Engineering, Construction, and Operation (AECO) industry.  
The building information model (BIM) has been integrated with process mining to get insights regarding the bottlenecks during the construction process [13]. An unmanned aerial vehicle was used to generate as-built point cloud models which were then compared with the as-planned BIM model. As-planned models were translated into event logs using a software tool, the Evenlog service [14]. Then the as-built data was merged with the event logs to create as-built event logs. This enabled process mining analytics and insights were extracted regarding bottlenecks and deviations during the construction process.  
Recent years have seen an increase in the modular construction of housing units which are built inside a factory and then transported to the construction site. [PERSON] and [PERSON] [15] used process mining to discover the construction process of modular construction in the factory. Radiofrequency identification (RFID) technology was used to track the modular units as they passed from one station to another. The event log was generated from the time-synced location data of the modular units, and the alpha algorithm was used to discover the underlying sequence of the operation.  
As the AEC industry is rapidly moving towards an intelligent and databased direction, a study proposed a framework to retrieve new data structure of command-object graphs from 3D modeling event logs [16]. The case study demonstrated that the 3D modeling event logs can provide quantitative and traceable data for early design stages which can add significant value to the later stages of the construction.  
A review paper analyzed sixty-two published articles regarding the application of data mining and process mining in underground mining activities [17]. While there were significant works in the domain of data mining, the authors could find only a handful of papers related to process mining applications in underground mining. Despite the lack of research efforts, the process mining papers exhibited the potential of such technique in process improvement and efficiency increasing by using process discovery, conformance checking, and process enhancement.