| This thesis defines what dynamic reconfiguration means in the context of software components that interact to implement services by formulating models that explicitly specify the relationships that exist among changing global or local system properties, changing behavioral or structural system signatures, and intra- or inter- component change. Using a running example of the dynamic inter-operation of two financial analysis systems, it identifies and categorizes the various types of change that are required, the relationships among those types, and the system integrity characteristics that need to be considered when such changes take place.; A use case specifies the common and variable causal flow of dynamic reconfiguration. It describes the different levels of dynamism as alternatives based upon change groups. The following change groups are identified: Pure Architectural Change, Pure Behavioral Change, Behavior-driven Structural Change, Comprehensive Behavior-driven Change, Pure Structural Change, Structure-driven Behavioral Change, Comprehensive Structure-driven Change, Pure Behavioral and Structural Change and Comprehensive Change. Each change group is defined to be composed of a set of related change sequences that describe how a particular change group unfolds. A change sequence combines a subset of the change types that apply within the sequence; the change types of a change sequence determine whether the particular change sequence implies architectural, behavioral, and/or structural change.; The following types of change are identified: Architectural Change, Topology Change, Substitution, Protocol Change, Interface Change, and Internal Change.; Architectural Change affects the model elements Global Property and Local Property. There is an indirect affect upon a system's structural or behavioral signature that in turn affects the configuration of other domain model elements. Topology Change affects the model elements Component and Communication Path. Substitution affects the model elements Component and Connection. Protocol Change affects the model element Service Protocol. Interface Change affects the model elements Required Service or Provided Service. Internal Change affects the model elements Operation, State Element, and Service Invocation. To ensure overall system consistency in the face of change, change types are related to seven system integrity management areas through the domain model elements that underpin the interdependency. |
