Mixing Workflows and Components to Support Evolving Services

Abstract

Composite distributed services involve local and remote services that get orchestrated according to specific business logic. This logic can be programmed by applying a traditional general-purpose programming language, but is generally described using a workflow language that coordinates a set of given services. The services involved in the composition, or the composition may need to evolve both at the business logic level (workflow level) and the global architecture level. This paper presents a solution to ease such evolution for compound distributed services and the authors’ proposal enables the evolution of both the business logic and the underlying architecture. This paper suggests relying on a distributed software component model to represent and easily manage the set of local or remote software entities (services) involved in the composition. Composite services are represented in a model that combines the use of a distributed and hierarchical software component model and new timed-automata based workflow language. This combination makes explicit the separation between functional and non-functional concerns, and as a consequence this approach helps in defining the required and various evolution procedures in context to compound services.

Genetic Improvement of Routing Protocols for Delay Tolerant Networks

“…The latter is based on the concept of "autocatalytic software" [76] or chemical computing [54]; essentially, protocols emerge automatically as collections of "fraglets, " i.e., combinations of code segments and parameters that are evolved, respectively, by distributed GP [89,90] and distributed EAs [4], and spread over the network through opportunistic (epidemic) propagation [3] regulated by interactions with the environment. On top of this, another EA optimizes the combination of protocols, i.e., the protocol stack [8,29,55].…”