Evolving Wireless Sensor Network Behavior Through Adaptability Points in Middleware Architectures

Reflection has been proven to be a powerful mechanism to address software adaptation in middleware architectures; however this concept requires that the middleware be open and that modification of all of its functionality and behavior be possible. This leads to systems which are difficult to understand and may quickly overwhelm developers. Safer and more understandable approaches use modeling and put forth a partial implementation of reflective principles while limiting the possible scope of modification, as with translucent middleware. We consider that given the resource constraints in a Wireless Sensor Network (WSNs) it is preferable to limit reflective features in order to conserve computational cycles and reduce network traffic. Additionally we do not believe all modifications lie within the concerns of the application developer and we introduce a separation of operational concerns that maps different modification responsibilities and levels of abstractions to different operational roles. We introduce a middleware architecture that provides strategy-controlled adaptability points; which are available to modify the behavior of the middleware's primary functionality. We have evaluated our approach through the implementation of a proof of concept prototype that supportsan industrial use case in the logistics domain and aneed-for-change scenario in the middleware's capacity planning functionality. Results demonstrate how changes in business requirements may be effectively supported through the introduction of adaptability points.