Offline Specialisation in Prolog Using a Hand-Written Compiler Generator

The so called "cogen approach" to program specialisation, writing a compiler generator instead of a specialiser, has been used with considerable success in partial evaluation of both functional and imperative languages. This paper demonstrates that the "cogen" approach is also applicable to the specialisation of logic programs (called partial deduction when applied to pure logic programs) and leads to effective specialisers. Moreover, using good binding-time annotations, the speed-ups of the specialised programs are comparable to the speed-ups obtained with online specialisers. The paper first develops a generic approach to offline partial deduction and then a specific offline partial deduction method, leading to the offline system LIX for pure logic programs. While this is a usable specialiser by itself, its specialisation strategy is used to develop the "cogen" system LOGEN. Given a program, a specification of what inputs will be static, and an annotation specifying which calls should be unfolded, LOGEN generates a specialised specialiser for the program at hand. Running this specialiser with particular values for the static inputs results in the specialised program. While this requires two steps instead of one, the efficiency of the specialisation process is improved in situations where the same program is specialised multiple times. The paper also presents and evaluates an automatic binding-time analysis that is able to derive the annotations. While the derived annotations are still suboptimal compared to hand-crafted ones, they enable non-expert users to use the LOGEN system in a fully automated way Finally, LOGEN is extended so as to directly support a large part of Prolog's declarative and non-declarative features and so as to be able to perform so called mixline specialisations. In mixline specialisation some unfolding decisions depend on the outcome of tests performed at specialisation time instead of being hardwired into the specialiser

A model for organizing and analyzing integration of environmental concerns in product design and re-design

Based on examples from research and innovation within nanotechnology, housing, bioenergy, and clothing the complexity of environmental innovation is discussed. A model for a more holistic approach to environmental innovation, which can be used both as part of innovation processes and for analyses of previous innovation processes, is developed. The approach is based on: 1) A scenario perspective on environmental aspects and impacts which implies a focus on the future roles of a product, its users and the surrounding society as imagined by the designers in their considerations about the problems addressed by the product and the solution it is offering. 2) A system’s perspective which implies a focus on the system, which a product is part of, including the need for supporting infrastructures like stakeholder training, waste management etc. 3) A lifecycle perspective to environmental aspects and impacts in order not only to capture environmental aspects from cradle to grave, e.g. related to material extraction and refining, chemical exposure during manufacturing, use and waste handling. 4) A governance perspective on management of environmental aspects and impacts, both in relation to the legitimacy of the environmental problems addressed and the solutions ‘offered’ by the product.</jats:p