Multi‐level modeling approach for the availability assessment of e‐business applications

Abstract

This paper defines a multi-level modeling approach for availability assessment of e-business applications, based on two main steps: (1) hierarchical description of the system and its interactions with the users, from the functional and structural points of view, and (2) hierarchical construction and solution of the availability models based on information from the first step. Four modeling abstraction levels are considered. The highest level (user level) describes the availability of the e-business application as perceived by the users. Intermediate levels describe the availability of functions and services provided to the users. The lowest level describes the availability of the component systems on which functions and services are implemented. The availability measures of a given level are computed based on the measures provided by the immediately lower level.

On composing Dependable Web Services using undependable web components

“…The current work on WS verification and validation is being carried out in several directions, including testing (Tsai et al, 2004) and model-based verification (Foster et al, 2003). A novel approach to dependability evaluation focusing on availability assessment is proposed in Kaaniche et al (2003). Paper (Tartanoglu et al, 2003b) analyses several existing approaches to incorporating fault tolerance measures (including both backward and forward error recovery mechanisms) into the composite WSs.…”