Realizability of Service Specifications

Autor: Gregor von Bochmann, Mohammad F. Al-hammouri
Rok vydání: 2018
Předmět:
Zdroj: System Analysis and Modeling. Languages, Methods, and Tools for Systems Engineering ISBN: 9783030010416
SAM
DOI: 10.1007/978-3-030-01042-3_8
Popis: This paper considers a global requirements model in the form of partially ordered actions of UML collaborations, or a high-level MSC (UML interaction sequences), and then studies the derivation of a distributed design model which may include coordination messages exchanged between the different system components. Different problems for the direct realization (without coordination messages) of a design model for special cases of alternatives followed by strict or weak sequence are discussed and solutions provided. Then the case of a weak while loop is considered. While previous work proposes the addition of sequence numbers in the involved messages, we show that in most cases such sequence numbers are not required. We consider message FIFO transmission or without order, and identify two potential problems: loop termination race, and message overtaking. A proposition is given which states under which conditions the directly realized distributed design model does not have these problems and therefore does not need additional sequence numbers. Another proposition provides certain modifications (including the addition of sequence numbers) that can be applied to the design model when these problems are present, and such that the resulting design model conforms to the requirements. These results can be viewed as an improvement of the previous work in [1] by minimizing the number of additional sequence numbers that must be included in the messages of a weak while loop collaboration.
Databáze: OpenAIRE
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