Deep learning-based extraction of construction procedural constraints from construction regulations

Construction procedural constraints are critical in facilitating effective construction procedure checking in practice and for various inspection systems. Nowadays, the manual extraction of construction procedural constraints is costly and time-consuming. The automatic extraction of construction procedural constraint knowledge (e.g., knowledge entities and interlinks/relationships between them) from regulatory documents is a key challenge. Traditionally, natural language processing is implemented using either rule-based or machine learning approaches. Limited efforts on rule-based extraction of construction regulations often rely on pre-defined vocabularies and involve heavy feature engineering. Based on characteristics of the knowledge expression of construction procedural constraints in Chinese regulations, this paper explores a hybrid deep neural network, combining the bidirectional long short-term memory (Bi-LSTM) and the conditional random field (CRF), for the automatic extraction of the qualitative construction procedural constraints. Based on the proposed deep neural network, the recognition and extraction of named entities and relations between them are realized. Unlike existing information extraction research efforts using rule-based methods, the proposed hybrid deep learning approach can be applied without complex handcrafted features engineering. Besides, the long distance dependency relationships between different entities in regulations are considered. The model implementation results demonstrate the good performance of the end-to-end deep neural network in the extraction of construction procedural constraints. This study can be considered as one of the early explorations of knowledge extraction from construction regulations.