Requirements traceability in model-driven development: Applying model and transformation conformance

The variety of design artifacts (models) produced in a model-driven design process results in an intricate relationship between requirements and the various models. This paper proposes a methodological framework that simplifies management of this relationship, which helps in assessing the quality of models, realizations and transformation specifications. Our framework is a basis for understanding requirements traceability in model-driven development, as well as for the design of tools that support requirements traceability in model-driven development processes. We propose a notion of conformance between application models which reduces the effort needed for assessment activities. We discuss how this notion of conformance can be integrated with model transformations

Natural decay resistance of Eysenhardtia polystachya (Ortega) Sarg.

In its area of distribution, the heartwood of Eysenhardtia polystachya (palo dulce) is empirically known to be very durable. To verify the reputed high natural durability, its resistance to wood degrading fungi was tested by means of the soil block and agar block tests using two white rot (Trametes versicolor and Phanerochaete chrysosporium) and two brown rot (Postia placenta and Gloeophyllum trabeum) fungi. Recorded mass losses for the soil block test (between 1�3 and 3�8%) were significantly lower than for the agar block test (between 7 and 10%). The higher mass loss in the agar block test is believed to be partly due to migration of extractives out of the blocks and not due to loss in mass as a result of fungal decay. According to the numerical values of mass loss recorded for the two test series, E. polystachya heartwood is rated 'highly resistant' (class 1 according to ASTM D 2017-05 - soil block test) and 'durable' (class 2 according to EN 350-1 - agar block test). � 2011 IWSc, the Wood Technology Society of the Institute of Materials, Minerals and Mining