Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DATA : 19/12/2017
HORA: 13:30
LOCAL: Auditório 1 do DIMAp

Recovery Mechanisms Based on Rewriting Process for Web Service Compositions


Fault Recovery, Web Services, Rewriting of Service Compositions.

GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Ciência da Computação
SUBÁREA: Teoria da Computação
ESPECIALIDADE: Lógicas e Semântica de Programas
As any distributed system, Web service compositions are exposed to a wide variety of failures. The service components remotely located can represent potential problems due to the means of connectivity necessary for communication or because of changes implemented by their respective provider during system updates. Those problems represent unpredictable events that compromise the correctness and availability of the service composition. The capacity to handle the faults and to maintain the distributed system available directly impacts on the reliability of the business process. The substitution of unavailable components, by equivalent services, can be considered as a viable solution to complete the specification of the distributed system correctly. Conveniently, the refinement process executed during the development considers correctness and completeness while searching for concrete compositions that translate the specification of the system provided by the user. Therefore, the goal of this work is to propose the development of a fault recovery mechanisms based on the rewriting process for Web service composition. The replacement of failed components is the principle of the recovery strategies and the adapted rewriting techniques are supposed to guide the provision of valid available candidates for the substitutions. The levels of recovery are considered to define different parts of the composition for the replacement, therefore, improving the capacity of the recovery mechanisms. Three levels are proposed: (i) local recovery, (ii) partial recovery and (iii) full recovery. Initially, the mechanism on local recovery only considers the replacement of the failed component. If recovery is unsuccessful due to lack of candidates that are compatible with the rest of the well functioning composition, the partial recovery is considered to replace all the components that were not executed before the failure. If the problem persists, then the recovery mechanism tries to find an entirely new concrete composition to execute the business process considering the full level of recovery. The suggestion of new components follows the order defined by the user preference on the execution of each available concrete service. This feature is inherited from the automatic rewriting processes that includes the user preference on their computation. The results of this work enable the analysis of the efficiency of those recovery mechanisms and their levels of recovery on distinct scenarios of failures on Web service compositions.

Presidente - 1495704 - UMBERTO SOUZA DA COSTA
Externo à Instituição - GENOVEVA VARGAS-SOLAR - CNRS
Notícia cadastrada em: 15/12/2017 15:00
SIGAA | Superintendência de Tecnologia da Informação - | | Copyright © 2006-2023 - UFRN -