PhD Oral Exam - Alhusain Mohamed Taher, Information Systems Engineering

When studying for a doctoral degree (PhD), candidates submit a thesis that provides a critical review of the current state of knowledge of the thesis subject as well as the student’s own contributions to the subject. The distinguishing criterion of doctoral graduate research is a significant and original contribution to knowledge.

Once accepted, the candidate presents the thesis orally. This oral exam is open to the public.

Abstract

In a typical construction project, a significant amount of information is communicated to various stakeholders at different phases of the project lifecycle. The communication of this information tends to be informal and ad-hoc in the majority of the cases, which makes it more susceptible to loss of information or misinterpretation. Earthwork operations, which are one of the main operations of construction projects, also struggle with the challenge of effective information communication. There is an apparent shortcoming regarding the unified structure for data and information exchange in this domain. The existing models and ontologies do not address the explicit semantic representation of earthwork operations. Accordingly, there is a need for a knowledge model to formalize the efficient communication of information. An ontological model can be used to organize the domain knowledge so that it can be utilized and reused by the stakeholders.

The primary purpose of this study is to develop an ontology for the earthwork domain that can be used to create the semantics-based integration method to support the communications between the different disciplines and stakeholders in the earthwork domain.

Accordingly, the objectives of this study are: (1) To extract the explicit and tacit knowledge required for the earthwork domain; (2) To formalize the extracted knowledge by developing the Earthwork Ontology (EW-Onto); (3) To develop methods for linking and coupling EW-onto with other existing relevant ontologies in the construction domain to extend its application for safety and productivity; and (4) To evaluate the integrated ontology (IEW-Onto) and apply the ontological model in supporting the development an application, which is a Multi-Agent System (MAS) in the earthwork domain.

In the proposed framework, the ontology integrates the different components in the domain. The extended earthwork ontology (called Integrated Earthwork Ontology or IEW-Onto) is composed of the concepts, relationships, and axioms in this domain and can represent the semantic values of the entities and the relationships. Each entity is linked with other entities with different types of relationships, such as is-a, part-of, operates, and coordinates. IEW-Onto benefits from the available ontologies in the construction domain, and links with other ontologies, such as sensor and soil ontologies. IEW-Onto is used to build the earthwork operation model as a pattern to represent the operations and processes sequences, which provide a reusable pattern for several applications such as MAS. The developed MAS can cope with the complexity of earthwork operations’ communication at the fleet level and addresses safety issues. In the MAS, every piece of equipment is represented by a dedicated computer agent. This Ontology-based MAS is expected to improve the safety of earthwork operations. Different evaluation methods were used to evaluate EW-Onto and IEW-Onto, including checking consistency, survey, data-driven and application-based validations. The evaluation results show that both ontologies have consistency and provide a high level of clarity, richness, comprehensiveness, interpretability, and effectiveness of the presented knowledge in the earthwork domain.