A Reflective Service Gateway for Integrating Evolvable Sensor-Actuator Networks with Pervasive Infrastructure

Service gateways (SGs) are a promising approach to integrate wireless sensor and actuator networks (SANETs) with pervasive infrastructure over Internet by encapsulating distributed physical sensor and actuators into regular objects. Typically, SGs for SANETs are assumed to know operational environment in advance at design time with limited awareness of operational SANET conditions and, in the meanwhile, provide a single particular form of access without knowledge of application activities. As a SANET evolves, end users will frequently add sensor and actuator nodes (SANs) for additional services, remove defective or obsolescent SANs, and upgrade SANs in deployed SANETs. Therefore, traditional SGs are infeasible to integrate the future evolvable SANET (ESANET) with the pervasive infrastructure. In this paper, we introduce the reflective service gateway (RSG) architecture combined with ESANET management functions. RSG enables heterogeneous middleware systems to concurrently access ESANETs. In addition, by reflection mechanism where network management functions are explicitly reified and integrated into RSG so that it can learn the changing ESANET runtime environment, RSG self-adapts to ESANET dynamics and enables ESANETs to customize its activities according to application services involved. To validate the RSG, we have implemented the RSG and conducted empirical performance measurements with home sensor and actuator applications using ZigBee.