# Integration of EMU Overall Design Model Based on Ontology-Knowledge Collaboration
## 3 Integration of EMU Requirement Models
### Requirements Ontology Construction  
When constructing the ontology framework for the requirements domain, the selection of an appropriate ontology aids in defining and organizing the concepts, relationships, and attributes of requirements. For the construction of the requirements ontology for the EMU, this study opts for the BFO as a fundamental formalization ontology to delineate entities and relationships across various domains. This ensures the standardization of the requirements ontology and its compatibility with other ontologies. Furthermore, the  
Figure 2: Process of Requirement Model Design. design of BFO incorporates scalability, allowing for the customization and extension of the requirements ontology to meet specific project needs. The construction of the requirements ontology can mitigate issues such as vague requirement definitions, communication barriers, and uncontrolled requirement changes. By utilizing an ontology, teams can articulate requirements in a more formalized and precise manner, thereby enhancing communication efficiency, reducing ambiguity, and facilitating effective management of requirement changes. This approach ensures that project teams gain a better understanding of and meet system requirements throughout the entire software development lifecycle. During the transformation process from requirements to ontology, employing a unified requirement exchange format is essential. This process aims to establish a consistent, easy-to-maintain, and extendable ontology for improved understanding and management of system requirements.By integrating architecture through a top-level ontology and using a unified requirement exchange format as a medium, an effective connection between requirements and ontology is achieved. The process from requirements to ontology is depicted in Figure 3. Upon completing requirement collection, standardized requirements are imported into the ontology using the Requirements Interchange Format (ReqIF) [38] standard to form the requirement ontology model. This process employs a unified requirement exchange format as a medium to standardize and represent requirements from diverse sources, thereby reducing ambiguity and misunderstanding in the transformation process from requirements to ontology. Moreover, it simplifies requirement mapping and conversion tasks, ensuring consistency across multiple domains or systems. The ReqIF was standardized by the Object Management Group in 2011 and is currently utilized in various fields such as transportation, industrial automation, and medical devices [39]. ReqIF, an XML-based exchange format, is designed to define a tool-independent standard for representing key features of requirement data. The standard encompasses requirement data elements such as attribute data elements, links (traces), requirement data views, and permission data forms. Its primary objective is to achieve a \"single-source-of-truth\" for requirements, ensuring consistency among different requirements and reducing defects from requirements to engineering work products, accelerating information exchange and collaborative solution development while also lowering costs. In software development and systems engineering, different requirement management tools are utilized to collect, analyze, and track project requirements, which possess varying data formats and structures, necessitating a standardized approach to pass requirement information. ReqIF offers universality, scalability, and structured data, serving as a generic requirement exchange format applicable to different domains and project types. Being XML-based, ReqIF supports meeting specific requirements management tool needs by adding custom tags or extending existing ones. ReqIF files organize requirement information in a structured manner, encompassing requirement attributes, relationships, and hierarchy. The standard is  
Figure 3: The conversion process from requirement to ontology.