Review By: Stuart Margach
07/08/2010In "Systems Modeling and Requirements Specification Using ECSAM," the authors present rich topics that progress from an elemental framework for reviewing system behavior static and dynamic states, events, transitions, and conditions into specialized domains. Inside these domains, systematic analysis is applied to decompose conceptual models into subordinate attributes. Successive examination of each of these parts addresses business imperatives that the system needs to fulfill.

The Embedded Computer Systems Analysis and Modeling method (ECSAM), developed by Lavi and Kudish, was originally used to support the evaluation of complex "embedded" systems extensively in the aerospace and engineering industry. This methodology has become a useful tool for requirements engineering modeling. It is based on a holistic approach that permits a detailed examination of hardware and software components to overcome inadequate or unrealistic requirement specifications.

The step-by-step approach in this book illustrates and explains the relevance of building a complete spectrum of views that take into account the system's external and internal dimensions. The purpose of the E-level model (black box) is to identify the externally observable system capabilities with the development of context diagrams for top-level views of the proposed architecture. It uses state charts and behavioral examination to gain better understanding of operational interactions and utilizes process modeling of identified capabilities to provide use cases for systematic testing purposes.

Next, the authors focus on the internal system properties with the S-level model (white box) assembling hierarchical representations of internal system behavior with successive iterative decomposition of these components into subsystems to allow for construction as separate units if required.

Lavi and Kudish provide good explanations of decomposition treatment for the internal properties of the system into subsystems, object analysis to establish key points for quality assurance, and analysis of the system's internal information flows to derive subsystem interface and capability specifications. They cover a range of techniques; evaluate the system's internal processes; collate the abstract representations and useful information, gleaned from S-level model results; and map these findings into the design model for the final solution.

From a lighter perspective, the authors provide information on the requirements management process, which is useful when dealing with a large number of requirements. Each chapter ends with series of exercises designed to reinforce the subject matter and put the theory into practice. A number of case studies at the end of the book extend the practicality and utilization of ECSAM method into the real world.

System engineers and developers will find the ECSAM methodology useful for its rigorous and disciplined approach for system analysis and modeling techniques. The ECSAM method provides a useful guide for system engineers in modeling operational, functional, performance, and interacting attributes for system development purposes.