The main concerns of CBSE related to components are a component specification, its implementation, and its deployment. A component is specified by functions by which it communicates with its environment, and by other attributes, called "extrafunctional attributes," which are not expressed by functions but define the total behavior of the component. A widely used method for specifying the syntactic aspects of functional properties is the definition of interfaces. The semantic aspects of functional properties related to context-dependencies (specification of the deployment and runtime environments) and interaction can be expressed using contracts. Interfaces and contracts, however, are not so well equipped to express extrafunctional properties. Manners and the analytical model are two examples of techniques that address the specification of extrafunctional properties. Component implementation and deployment are closely related to patterns and frameworks.

Comprehensive user evaluations of outdoor augmented reality (AR) applications in the architecture, engineering, construction and facilities management (AEC/FM) industry are rarely reported in the literature. This paper presents an AR prototype system for infrared thermographic façade inspection and its evaluation. The system employs markerless tracking based on image registration using natural features and a third person perspective (TPP) augmented view displayed on a hand-held smart device. We focus on evaluating the system in user experiments with the task of designating positions of heat spots on an actual façade as if acquired through thermographic inspection. User and system performance were both assessed with respect to target designation errors. The main findings of this study show that positioning accuracy using this system is adequate for objects of the size of one decimeter. After ruling out the system inherent errors, which mainly stem from our application-specific image registration procedure, we find that errors due to a human’s limited visual-motoric and cognitive performance, which have a more general implication for using TPP AR for target designation, are only a few centimeters.