The level of maturity that has been reached by model transformation technologies is proved by the growing literature on transformation libraries that address an increasingly wide spectrum of applications. With the success of the modeling and transformation paradigm, the need arises to address more complex applications that require a direct manipulation of model transformations. The uniformity a...

An N -dimensional digital binary image (I) is a function I : Z → {0, 1}. I is B3N−1,W3N−1 connected if and only if its black pixels and white pixels are each (3 − 1)-connected. I is only B3N−1 connected if and only if its black pixels are (3 − 1)-connected. For a 3-D binary image, the respective connectivity models are B26,W26 and B26. A pair of (3 N − 1)-neighboring opposite-valued pixels is c...

The degree distribution of scale-free Small World networks follows a power law. For random graph generators, its exponent is constrained by the construction mechanism, whereas in real-world data, different slopes can be observed. However, the degree distribution alone does not reveal much of the local structure of these graphs. Therefore, we propose a graph transformation we call ”higher order”...

It has been suggested that the chiral symmetry can be implemented only in classical Lagrangians containing higher covariant derivatives of odd order. Contrary to this belief, it is shown that one can construct an exactly soluble two-dimensional higher-derivative fermionic quantum field theory containing only derivatives of even order whose classical Lagrangian exhibits chiral-gauge invariance. ...

We consider the lagrangian L = F (R) in classical (=non-quantized) two-dimensional fourth-order gravity and give new relations to Einstein’s theory with a non-minimally coupled scalar field. We distinguish between scale-invariant lagrangians and scale-invariant field equations. L is scale-invariant for F = c1R k+1 and a divergence for F = c2R. The field equation is scale-invariant not only for ...

Compiling syntax to native code requires complex code transformations which rearrange the abstract syntax tree. This can be particularly challenging for languages containing binding constructs, and often leads to subtle, hard to find errors. In this paper, we exploit higher-order abstract syntax (HOAS) to implement a type-preserving compiler for thesyntax (HOAS) to implement a type-preserving c...

Model-driven engineering is a wide-spread paradigm in modern software engineering. During the last couple of years, many tools and languages have been developed, which are especially designed for model transformations — a discipline which is needed in many model-driven engineering approaches. While most of the existing model-to-model tools and languages are tailored towards batch transformation...

We consider two classes of stream-based computations which admit taking linear combinations of execution runs: probabilistic sampling and generalized animation. The dataflow architecture is a natural platform for programming with streams. The presence of linear combinations allows us to introduce the notion of almost continuous transformation of dataflow graphs. We introduce a new approach to h...

For about two decades, researchers have been constructing tools for applying graph transformations on large model transformation case studies. Instead of incrementally extending a common core, these competitive tool builders have repeatedly reconstructed mechanisms that were already supported by other tools. Not only has this been counterproductive, it has also prevented the de nition of new la...