Summary of a Literature Review in Scalability of QoS-aware Service Composition <s> [RQ1.] How are authors on QoS-based dynamic service composition evaluating the scalability of their solutions? <s> The term scalability appears frequently in computing literature, but it is a term that is poorly defined and ::: poorly understood. It is an important attribute of computer systems that is frequently asserted but rarely ::: validated in any meaningful, systematic way. The lack of a consistent, uniform and systematic treatment ::: of scalability makes it difficult to identify and avoid scalability problems, clearly and objectively describe ::: the scalability of software systems, evaluate claims of scalability, and compare claims from different ::: sources. ::: This thesis provides a definition of scalability and describes a systematic framework for the characterization ::: and analysis of software systems scalability. The framework is comprised of a goal-oriented ::: approach for describing, modeling and reasoning about scalability requirements, and an analysis technique ::: that captures the dependency relationships that underlie typical notions of scalability. The framework ::: is validated against a real-world data analysis system and is used to recast a number of examples ::: taken from the computing literature and from industry in order to demonstrate its use across different ::: application domains and system designs. <s> BIB001 </s> Summary of a Literature Review in Scalability of QoS-aware Service Composition <s> [RQ1.] How are authors on QoS-based dynamic service composition evaluating the scalability of their solutions? <s> Scalability is a critical concern for many software systems. Despite the recognized importance of considering scalability from the earliest stages of development, there is currently little support for reasoning about scalability at the requirements level. This paper presents a goal-oriented approach for eliciting, modeling, and reasoning about scalability requirements. The approach consists of systematically identifying scalability-related obstacles to the satisfaction of goals, assessing the likelihood and severity of these obstacles, and generating new goals to deal with them. The result is a consolidated set of requirements in which important scalability concerns are anticipated through the precise, quantified specification of scaling assumptions and scalability goals. The paper presents results from applying the approach to a complex, large-scale financial fraud detection system. <s> BIB002
Scalability is the ability of a system to maintain the satisfaction of its quality goals to levels that are acceptable to its stakeholders when characteristics of the application domain and the system design vary over expected operational ranges BIB002 . Therefore, any analysis of an ordinary software quality in the presence of the variation of characteristics of the application domain and system design is, in fact, a scalability analysis BIB001 . We have observed that, out of 47 papers, 41 present some form of scalability analysis or claims. Some are explicit, as in paper [P2] which has a section entitled "QoSMOS Scalability, where authors analyse execution time with respect to the number of concrete services and abstract medical services. A similar section is presented in paper[P39],where authors evaluate the execution time of the algorithm with respect to the number of concrete services, abstract services and QoS constraints for a service composition. Other works present varied analyses without an explicit mention of the term "scalability". This is the case of the paper [P10], which test for the percentage of optimal solutions found given an increasing number of services to combine. 