Introduction
Contemporary cities face escalating risks from natural hazards and human-induced threats owing to rapid population growth, infrastructural complexity, and spatial densification (Rezaie Narimisa et al., 2019). Enhancing urban resilience has therefore emerged as an urgent imperative. Within this context, passive defense—a non-confrontational strategy aimed at vulnerability reduction and improvement of absorption, response, and recovery capacities—offers a robust framework for threat mitigation at the neighborhood scale (Ghajari et al., 2018).
As the primary organizational units of urban fabric, neighborhoods constitute critical arenas for implementing passive defense measures. Public and strategic facilities located within them are frequently primary targets during crises; consequently, reducing neighborhood-level vulnerabilities substantially strengthens societal defensive capacity. Accordingly, this study examines neighborhood resilience in Qom City, Iran, through the lens of passive defense, addressing three principal research questions:
• How do neighborhood spatial indicators (green space provision, building density, and distance from strategic centers) exert direct and indirect influences on shelter design criteria and overall neighborhood resilience?
• Which shelter design criteria do experts regard as most critical to neighborhood resilience, and how are these criteria hierarchically ranked?
• How does the prioritization of shelter design criteria differ according to shelter function (public, hospital, command), and what are the implications for resilience planning?

Theoretical Framework
The neighborhood represents a multifaceted construct in urban studies, encompassing social, perceptual, physical, functional, and political dimensions. Internationally, neighborhoods are typically conceptualized as spatially bounded areas possessing distinct identity and providing daily services within convenient walking distance. In the Iranian context, official guidelines define neighborhoods as units containing 700–1,250 households accessible within a 4–5-minute pedestrian radius and anchored by mosques, schools, parks, and local commercial facilities.
Beyond demographic and service thresholds, collective identity, social interaction, spatial legibility, environmental quality, and physical continuity are pivotal to neighborhood cohesion. The neighborhood scale is particularly salient for passive defense and resilience planning, as it aligns with citizens’ lived experience and hosts essential infrastructure and population concentrations. Core passive defense principles—appropriate site selection, concealment and camouflage, emergency circulation networks, structural reinforcement, and multifunctional space design—are most effectively operationalized at this level. Moreover, neighborhood resilience extends beyond technical parameters to incorporate social capital, access to open space, environmental quality, and service coordination. Within this integrated perspective, shelter design emerges as a vital nexus of technical, spatial, and socio-functional considerations, yielding safe and adaptable refuges during crises.

Methodology
This applied investigation adopted a descriptive–analytical design. Data were collected through documentary review, field observation, expert questionnaires, and geospatial analysis. The study area comprised Qom City, with three representative neighborhoods (Pardisan, Emam, and Shahrak-e Qods) selected via cluster sampling. Expert judgment was elicited from 12 specialists in architecture and passive defense using structured questionnaires. Quantitative analysis and structural equation modeling were performed using SPSS 26 and AMOS 24 software.

Results and Discussion
Expert assessments, validated by the Friedman rank test, established structural resistance and emergency evacuation routes as the preeminent shelter design criteria (highest mean ranks). Spatial indicators significantly moderated these criteria: green space provision and greater distance from strategic centers correlated positively with structural resistance and accessibility, whereas elevated building density exhibited inverse relationships.
Criterion prioritization varied markedly by shelter typology. Emergency routes emerged as the dominant consideration for hospital shelters, reflecting the imperative of rapid patient evacuation and ambulance access. Conversely, concealment and camouflage assumed primary importance for command centers to minimize detection risk. Structural resistance and strategic location, however, retained universal salience across all functional categories.
Structural equation modeling confirmed that neighborhood resilience is shaped through both direct pathways (safety-oriented design criteria and favorable physical attributes) and indirect pathways mediated by design criteria. Hierarchical cluster analysis delineated three neighborhood typologies: (1) planned resilient neighborhoods exhibiting optimal spatial characteristics and high design compliance; (2) dense vulnerable neighborhoods constrained by excessive building density and limited open space; and (3) location-dependent neighborhoods whose resilience hinged predominantly on proximity to or distance from strategic assets. These typologies facilitate targeted, context-specific interventions.
The results affirm the necessity of a systemic approach that integrates shelter design standards with neighborhood physical planning, acknowledges functional differentiation, and leverages spatial analytics to strengthen urban resilience.

Conclusion
This investigation demonstrates that structural resistance and emergency evacuation routes constitute the cornerstone shelter design criteria for enhancing neighborhood resilience, followed by strategic location and concealment measures. Neighborhood spatial characteristics—green space provision, building density, and distance from strategic centers—exert significant direct and indirect effects on criterion fulfillment and resilience outcomes. Furthermore, functional specialization markedly influences criterion hierarchy, with hospital shelters prioritizing circulation efficiency and command facilities emphasizing concealment.
Ultimately, achieving robust urban resilience necessitates the systematic integration of shelter design with neighborhood-scale spatial planning, explicit consideration of shelter function, and adoption of differentiated, evidence-based strategies tailored to local physical and strategic conditions. Such an approach will facilitate the development of resilient, adaptive urban shelter networks capable of withstanding contemporary threats.