The primary objective of EVOLVER is to develop a capability package that provides sufficient integrated development context in the form of a design information web that will significantly assist the processes of streamlined acquisition and software evolution. Current SEE's capture only artifacts and require the evolver to access each tool or artifact to discover and then assimilate necessary information. EVOLVER will know what information is needed when and establish a context to support user navigation through the information. A key thrust within EVOLVER is to communicate information (and ultimately knowledge) pertinent to requirements, design tradeoffs and software evolution history.
EVOLVER builds on a current DARPA STARS task which prototyped a SEE Information Interface Web (SEEWeb) within the context of an on-going program - the USTRANSCOM Global Transportation Network (GTN) - to support a streamlined acquisition approach where both contractor and Government reviewers are provided easy-to-use WWW-based access to information synthesized from life-cycle artifacts. SEEWeb provides the beginnings to our hyperweb environment (with established Service involvement) and grounds our approach in a practical solution, into which we will incorporate multi-media (beyond hypertext) and advanced technologies for increasingly dynamic updates and nonintrusive rationale capture and playback that will support evolution of legacy systems.
A two-level hypertext model dealing with the relationships among software artifacts is used to improve the expressiveness of the hypertext. A semantic network (DARPA STARS Open-RLF) acts in the role of a mediator enabling semantically rich dynamic links within the information web providing a level of link abstraction that is required if the hypertext system is to be adaptive. The abstraction allows the system to provide the appearance of an extremely malleable hyperspace which is nonetheless drawn out of a primarily static set of nodes and links.
The multi-media design narrative capability of EVOLVER will employ a narrative "story telling" approach that captures the frequent goal shifts and associated design impacts that occur in real-world software evolution. The focus will be on narrative guided navigation through the hypercode web using desktop VR employing literate programming and dramatic presentation metaphors to provide the structural framework for telling the story of a design's evolution and desktop VR (implemented using VRML toolkits) to immerse the evolver into a virtual design world in which the complex interrelationships of the design web are made accessible and comprehensible.
The EVOLVER team is taking an architecture-based incremental prototyping approach. Each release of the EVOLVER core prototype is intended to be usable for on-going validation experiments. Beginning with the STARS SEEWeb base which provides an initial mediated architecture and is implemented using KQML and JAVA, the FY97 prototypes will add two-level hypertext capability and FY98 will focus on multi-media design narrative. Resource discovery agents that can automatically construct plausible hypertext links in a heterogeneous corpus of text, graphics, code, comments and knowledge-base objects will come into play in FY98 and migrate to the core EVOLVER in FY99.
EVOLVER prototypes will help to establish the utility of the approach and can be used "as-is" with the underlying environment (tools) used in the prototype. This task also involves packaging of the technologies into sets of capabilities and guidance so that they may be more easily instantiated for particular organization's needs/requirements. The EVOLVER package will thus provide a toolkit for creating multi-media narrative-based design records tailored to the organization and the software artifacts it produces.