Bridging Apples and Oranges: A Schema for Defining QoS‑Aware Composition

Abstract

QoS-aware Web Service Composition (QoSWSC) addresses the challenge of selecting the most appropriate candidate services to fulfill a desired functionality while optimizing Quality of Service (QoS) attributes—such as cost, performance, and reliability—under user-defined constraints. Despite significant research in this area, reproducibility and comparability of results remain limited due to the lack of a standardized and formal problem definition. This paper introduces a problem definition schema for QoSWSC that captures the core elements required to describe such problems in a structured, unambiguous, and extensible way. By establishing a shared vocabulary and formal structure, the schema enables clearer communication, facilitates experimental replication, and supports future extensions—such as the development of a common model and syntax for defining problem instances. In addition, we explore how this schema addresses the persistent challenge of replicability and examine an emerging issue in the field: multi-configuration services. Together, these contributions pave the way for more rigorous, interoperable, and realistic approaches to modern service composition research.