这篇论文把空调故障诊断的知识结构做成了能查的本体，以后跨系统做FDD就不用各搞各的了。
FDD-ON是一个模块化、可扩展的本体，用于形式化表达变风量（VAV）空调系统组件、故障类型、症状状态及其影响。该本体整合了故障检测与诊断（FDD）语义，并通过定义受控词汇表来统一描述故障与症状属性。依赖造成原因-故障-症状-影响的四元关系，FDD-ON可为异质FDD输出提供机器可解释的映射基础。研究团队利用公开VAV数据集对该本体进行了评估，并展示了其在FDD应用开发中的实际效果。
Development of FDD-ON: an Ontology for VAV HVAC System Fault Detection and Diagnostics
Fault detection and diagnosis (FDD) technology is essential for improving HVAC system reliability, energy efficiency, and maintenance effectiveness. However, effective deployment of FDD solutions in buildings requires structured domain knowledge that can bridge heterogeneous data sources, diverse equipment types, and varied diagnostic outputs. Limited data interpretability and interoperability within the FDD domain have led to fragmented information silos, hindering the implementation of FDD and related applications, such as the digital twin-enabled FDD frameworks and artificial intelligence (AI)-driven maintenance decision-making systems. This paper presents an FDD Ontology (FDD-ON), a modular and extensible ontology to formally represent variable air volume (VAV) HVAC system components, fault types, symptom statuses, fault impacts and associated attributes. FDD-ON integrates HVAC system FDD semantics to provide comprehensive representations of fault and symptom attributes, supported by the well-defined controlled vocabulary. Additionally, FDD-ON offers comprehensive fault, symptom, and impact libraries to capture a broad spectrum of operational abnormalities and their consequences in VAV HVAC systems. Through explicit contributing cause-fault-symptom-impact relations, FDD-ON serves as a machine-interpretable basis for querying diagnostic knowledge, mapping heterogeneous FDD outputs, and developing interoperable FDD-related applications. FDD-ON is evaluated using publicly available VAV HVAC system datasets and demonstrated through FDD development applications. Results indicate that FDD-ON provides a foundational semantic framework for advancing scalable, transparent, and interoperable FDD solutions across various applications.