Disaster risk reduction involves implementing measures to reduce the risk of disasters and build community resilience to natural and human$-$induced hazards. Delve into the theoretical principles of disaster risk reduction, including risk assessment, early warning systems, and community$-$based disaster management. How do engineers and planners apply theoretical models of disaster risk reduction to develop mitigation measures, improve emergency preparedness, and promote sustainable development practices that enhance resilience and reduce vulnerability to disasters in at$-$risk communities?