AutomatedBuildings.com Article - Collaborating Services - the Challenges of Interoperability

The European Community has established a Global Interoperability Test Bed (GITB) initiative with a view to fostering better information exchanges between systems using XML. Clearly at the heart of enabling comfort, energy and environmental solutions is the accurate and timely exchange of information and notifications across a diverse ecosystem of devices and communications channels both within and outside a building.

Keeping the costs of achieving this so that consumers can afford the resulting products is therefore a challenge. What is needed is a selection of capabilities to test and verify the correct operations and information exchanges. Fortunately new tools are emerging from an open source initiative that is government focused, sponsored by Oracle and is also contributing to the GITB work. The focus is primarily toward facilitating the government National Information Exchange Model [NIEM] adoption (http://www.niem.gov) however all the same needs apply to building automation. These include the ability to establish a common domain vocabulary of terms and definitions along with a set of core components that implement those as XML content and mechanisms. Then common exchange packages based on those components that allow consistent and reusable handling and processing of the information and actions to occur. Allied to this is the need for an XML validation framework that is context and rule based not just rigid and brittle structure and content model validation. Having an adaptive framework allows templates to be published that express the information about particular exchanges and actions that provide for the formation of test suites. These test suites enable a community to develop common interoperable systems through a shared open source resource that can be freely utilized to align each individual solution to. This is the focus of the CAM project that is publicly available on Sourceforge.net (http://www.cameditor.org) and is an implementation of the OASIS Content Assembly Mechanism (CAM) public open standard (http://www.oasis-open.org/committees/cam).

The template approach allows the expression of structure, content, rules, context and annotations in a common format that is easily shared. These templates can then be read by the validation engine (CAMV) and applied to the example information exchanges to verify their alignment. The templates provide the flexibility to rapidly adapt the rules and content to match the scenarios and exchanges being designed for particular use by a set of systems, devices and applications. An implementation of the CAMV engine is available written in Java and it in turn has been integrated into a test harness using the ANT scripting tool, as shown in Figure 1 below of the test suite environment. For developing the actual templates themselves there is a visual editor toolkit along with a brief eight minute introductory tutorial video available that illustrates the major concepts and operations. The test suite implementation is available on Sourceforge.net and a step by step tutorial there provides the installation and configuration for a variety of platforms including Windows, Mac and LINUX.

Figure 1 – Test Suite Environment Conceptual Overview

The test suite with its set of templates and examples then forms the basis of collaboration to establish interoperability across a community of users. Referencing Figure 1 above the ANT scripting engine loads the control script which references the specific test template and then cycles through the test instances passing them individually to the CAMV validation engine (1). The validation results can be optionally passed to a post-validation rendering step (2) where an XSLT processor is used to output visual reports for analysis and diagnostic purposes.
Work is currently underway to utilize this approach for the US Elections community for sharing blank ballot delivery and voter entitlement information across jurisdictions, systems and devices with the similar needs to create interoperability, reuse and alignment with the associated cost savings and long term dependability this brings. An initial test suite has been built and this will be extended and refined during 2012 as field testing is performed using election data from individual States.

Currently the test suite is configured to run locally on each test system however planning to deploy this framework as part of the GITB international federated testing systems is underway. This will allow remote testing to be supported globally also where exchanges and actions are communicated directly to the test bed environment and the diagnostics logged and reviewed via an online dashboard console.

Summary

The development of collaborative test suite systems is a key enabler for establishing broad interoperability across a community and domain of solutions, systems and devices. This can potentially have benefits for the building automation world in accelerating the delivery and introduction of new systems and reducing the cost of verifying their interoperability with existing in situ components. Having a community open source and open standard system for test bed implementation enables this collaboration to occur. The approach provides for publishing a consistent package of templates, examples and documentation to allow implementers to quickly determine the requirements and constructs needed in XML. By using templates and rules that are context aware a broad spectrum of use cases can be accommodated using a single template. This adaptive approach is much more flexible than previous systems that relied primarily on XML schema and rigid structure definitions. Having fault tolerant and adaptive systems is essential for building automation.

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