## 4 Discussion
### Policy Implications  
To enhance urban resilience and promote coordinated and sustainable development in the BTHUA, the following recommendations are proposed.  
First, it is crucial to develop comprehensive resilience enhancement strategies that are grounded in the interdependence among SocR, EcoR, and TecR. Given that inadequate infrastructure and technological innovation are major obstacles for most cities in the BTHUA, TecR should be fully considered in the formulation of urban resilience enhancement strategies. When allocating capital and resources, prioritizing and continuously optimizing interactions among the three resilience subsystems is essential to maximize their collective contributions to overall resilience. To ensure effective implementation, a robust evaluation and monitoring mechanism should be established to regularly track and assess the progress and impact of resilience enhancement initiatives, thereby providing a basis for continuous improvement and adaptation.  
Second, it is important to enhance the radiation-driven role of key cities to optimize regional development patterns. Although urban development in the BTHUA has become more balanced, and several sub-regional high-performance clusters have emerged, significant gaps remain between cities. Given that key cities like Beijing exhibit high resilience and strong connectivity with surrounding cities, leveraging their advantages in human capital, economic development, infrastructure, and high-tech industries can enhance the learning and adaptive capabilities of neighboring cities. It is essential to continuously improve cooperation mechanisms to promote the joint construction and sharing of public services, thereby narrowing the regional development gap. Urban ecological spaces and infrastructure should be interconnected to form regional infrastructure and ecological corridor networks, facilitating resource and population flows, reducing redundancy, and strengthening intercity cooperation, thus enhancing the capacity for a coordinated response to regional challenges such as natural disasters or economic fluctuations.  
Third, implementing city-specific policies tailored to each urban context is vital for enhancing UA resilience. Considering the differences in coordinated development levels among cities and the specific challenges they face, formulating and implementing differentiated strategies that adapt to local conditions and address specific needs is critical. For example, cities such as Chengde and Zhangjiakou, where the CCD was moderate but EcoR was high, should accelerate the development of eco-friendly industries to promote socioeconomic development while preserving their ecological strengths. Meanwhile, cities such as Langfang and Xingtai, which had relatively high TecR but constraints in economic strength and public services, should leverage their technological advantages to accelerate industrial and social transformation. By promoting intensive and efficient resource use, these cities can overcome limitations and bolster their resilience. Overall, each city in the BTHUA should actively harness its unique assets, mitigate weaknesses, foster heterogeneous advantages, and achieve mutual benefits.