Towards a framework for interoperability of executable architectures

Abstract

As the approach to national defense becomes increasingly "capabilities" centric and the requirements on systems become increasingly sophisticated, there is a growing reliance on new capabilities produced by collections of interoperating existing (or easily modified) systems (an approach called System-of Systems or SoS). Evaluation of the viability of an SoS early in the conceptualization process, based on the architectural specification of its component systems, is essential to the confident development and use of that SoS. Investment in enterprise architecture models and artifacts such as those required by the Department of Defense Architecture Framework (DoDAF) cannot produce a guarantee of either interoperability or performance acceptability without the support of tools that automate verification and validation of the resulting models and artifacts. A diverse set of tools is in use today to support various aspects of enterprise architecture framework modeling, from developing graphic, tabular, or textual artifacts, to a limited capability for configuration control of those models. Unfortunately, there are no methods or tools to determine if an SoS specified by those models is capable of execution. In fact, effective methods to assure even syntactic (much less semantic) interoperability are yet to be defined. A method, a language, and a framework of supporting tools to facilitate the assessment of syntactic and semantic interoperability and performance of systems on the basis of their enterprise architecture specifications will be presented. Our framework and method require the design of an expressively rich language to represent the executable version of architecture models and artifacts. That language would have to coexist with other core product frameworks such as CADM and XML Metadata Interchange (XMI). Utility of the language will depend on a framework of tools for expressing and evaluating SoS architectures. We will describe an Executable Architecture Markup Language (EAML) that supports a representation of model executability by way of emulation and simulation paradigms. The concept of an Intelligent Toolkit for Interoperable Architectures (ITIA), which allows DoDAF modelers to translate, extend, and execute architectural models using EAML as the neutral format will be discussed. Finally, we will present how our method addresses the method of architecture-based capabilities descriptions and DoDAF-based architectures can be developed, modified, validated, and utilized. The capability described in this presentation is expected to provide value-add to a broad range of users, including senior military leaders, strategic military analysts, and various echelons of the military operators; as well as architects, systems analyst engineers, and system developers. The EAML and the ITIA toolkit are intended to be used in qualitative and quantitative analyses at various levels of an enterprise architecture framework. In particular, we define five levels of verification and validation-level 1 is consistency within a framework product; level 2 is model consistency between two products; level 3 is defined as consistency within a view set; i.e., within an operational view; level 4 is defined as consistency across view sets; e.g., between operational and systems views, and finally, level 5 is defined as consistency between architectures of different systems that form a system of systems. Orthogonally, we also define various types of verification and validation (VV e.g., ensuring that the context of an OCL statement is from a valid IDEF or UML model. Type 3 VV increased likelihood of achieving system, services, and capabilities goals; and a simplified, more-reliable operation of the resulting complex systems. By providing upfront verification and validation for performance, capability, interoperability, planning, and scheduling, the evaluation of SoS within the DoD will result in significant savings in both investment dollars and lives through the avoidance of flawed and unsafe systems.