Towards Generic Modularization Transformations

Modularization concepts have been introduced in several modeling languages in order to tackle the problem that real-world models quickly become large monolithic artifacts. Having these concepts at hand allows for structuring models during modeling activities. However, legacy models often lack a proper structure, and thus, still remain monolithic artifacts. In order to tackle this problem, we present in this paper a modularization transformation which can be reused for several modeling languages by binding their concrete concepts to the generic ones offered by the modularization transformation. This binding is enough to reuse different modularization strategies provided by search-based model transformations. We demonstrate the applicability of the modularization approach for Ecore models.Ministerio de Economía y Competitividad TIN2012-32273Junta de Andalucía TIC-5906Junta de Andalucía P12-TIC-186

Search‐based model transformations

Model transformations are an important cornerstone of model‐driven engineering, a discipline which facilitates the abstraction of relevant information of a system as models. The success of the final system mainly depends on the optimization of these models through model transformations. Currently, the application of transformations is realized either by following the apply‐as‐long‐as‐possible strategy or by the provision of explicit rule orchestrations. This implies two main limitations. First, the optimization objectives are implicitly hidden in the transformation rules and their orchestration. Second, manually finding the best orchestration for a particular scenario is a major challenge due to the high number of possible combinations. To overcome these limitations, we present a novel framework that builds on the non‐intrusive integration of optimization and model transformation technologies. In particular, we formulate the transformation orchestration task as an optimization problem, which allows for the efficient exploration of the transformation space and explication of the transformation objectives. Our generic framework provides several search algorithms and guides the user in providing a proper search configuration. We present different instantiations of our framework to demonstrate its feasibility, applicability, and benefits using several case studiesEuropean Commission ICT Policy Support Programme 317859Ministerio de Economia y Competitividad TIN2015-70560-RJunta de Andalucía P10-TIC-5960Junta de Andalucía P12-TIC-186

Search-Based Model Transformations with MOMoT

Many scenarios require flexible model transformations as their execution should of course produce models with the best possible quality. At the same time, transformation problems often span a very large search space with respect to possible transformation results. Thus, guidance for transformation executions to find good solutions without enumerating the complete search space is a must. This paper presents MOMoT, a tool combining the power of model transformation engines and meta-heuristics search algorithms. This allows to develop model transformation rules as known from existing approaches, but for guiding their execution, the transformation engineers only have to specify transformation goals, and then the search algorithms take care of orchestrating the set of transformation rules to find models best fulfilling the stated, potentially conflicting transformation goals. For this, MOMoT allows to use a variety of different search algorithms. MOMoT is available as an open-source Eclipse plug-in providing a non-intrusive integration of the Henshin graph transformation framework and the MOEA search algorithm framework

The Class Responsibility Assignment Case

This paper describes a case study for the ninth Transformation Tool Contest (TTC’16)1. The case is aimed at the production of high-quality designs for object-oriented systems and presents the problem of finding a good class diagram for a given set of methods and attributes with functional and data relationships among them. In order to obtain such a class diagram, dedicated quality metrics that have been defined in the context of the class responsibility assignment problem need to be optimized. Therefore, the focus of this case study is not on the definition of the necessary set of rules, but rather on the orchestration of such rules in order to find the optimal class diagrams. The evaluation of the produced transformation is driven by the quality of the produced models, the complexity of the rule orchestration as well as by the flexibility of the solution and its performance

Influence of rivet to sheet edge distance on fatigue strength of self-piercing riveted aluminium joints

Self-piercing riveting (SPR) is one of the main joining methods for lightweight aluminium automotive body structures due to its advantages. In order to further optimise the structure design and reduce the weight but without compromising strength, reduction of redundant materials in the joint flange area can be considered. For this reason, the influence of rivet to sheet edge distance on the fatigue strengths of self-piercing riveted joints was studied. Five edge distances, 5 mm, 6 mm, 8 mm, 11.5 mm and 14.5 mm, were considered. The results showed that the SPR joints studied in this research had high fatigue resistance and all specimens failed in sheet material along joint buttons or next to rivet heads. For lap shear fatigue tests, specimens failed in the bottom sheet at low load amplitudes and in the top sheet at high load amplitudes except for specimens with very short edge distance of 5 and 6 mm; whereas, for coach-peel fatigue tests, all specimens failed in the top sheet. For both lap shear and coach-peel fatigue tests, specimens with an edge distance of 11.5 mm had the best fatigue resistance. It was found that for coach-peel fatigue, length of crack developing path before specimens lost their strengths was the main factor that determined the fatigue life of different specimens; for lap shear fatigue, the level of stress concentration and subsequent crack initiation time was the main factor that determined the fatigue life

Erstellung, Erweiterung und qualitative Verbesserung des Pastinakensortiments für den ökologischen Anbau unter besonderer Berücksichtigung des Geschmacks; Weiterentwicklung der entsprechenden Zuchtmethoden

Es wurden 71 verschiedene Herkünfte und Zuchtstämme von 21 Pastinakensorten qualitativ geprüft. Der Anbau wurde teilweise an 5 Standorten in Deutschland über drei Jahre durchgeführt. Dabei konnten deutliche Einflüsse des Standortes und der Kulturführung festgestellt werden in Bezug auf Parameter wie Form, Geschmack und Ertrag und Inhaltsstoffe. An den Züchtungsstandorten des Vereins Kultursaat e.V. wurde die Methode der Geschmacksselektion entwickelt und für Pastinaken angewandt. Diese Methode hat sich bewährt und hat an einigen Sorten in einer Generation Geschmacksverbesserungen bewirkt. Dabei wurde mit Einzelpflanzennachkommenschaften von geschmacksselektierten Pastinaken gearbeitet. Die Methode der Geschmacksselektion ist relativ einfach und leicht durchführbar und wird im Bericht ausführlich beschrieben. Neben den sensorischen Untersuchungen und den Inhaltsstoffanalysen wurden Untersuchungen mit Bildschaffenden Methoden (Kupferchloridkristallisation nach E. Pfeiffer und Wala Steigbildmethode) durchgeführt, die eine weitere Vertiefung des Urteils über die Qualität der Pastinaken erlauben. Zusätzlich wurde die neu entwickelte Methode der rationalen, direkten Beobachtung der Bildekräfte, die der Konstitution und Gestalt der Pflanze zugrunde liegen, zur Untersuchung eingesetzt. Die Methode erlaubt einen entscheidenden Blick auf die Eignung der pflanzlichen Produkte für die Ernährung. Durch die Verbesserung des Genusswertes der Pastinake ist die Möglichkeit einer breiteren Verwendung in Küche und Verarbeitungsindustrie gegeben

Towards Pattern-Based Optimization of Cloud Applications

With the promise of seemingly unlimited resources and the flexible pay-as-you-go business model, more and more applications are moving to the cloud. However, to fully utilize the features offered by cloud providers, the existing applications need to be adapted accordingly. To support the developer in this task, different cloud computing patterns have been proposed. Nevertheless, selecting the most appropriate patterns and their configuration is still a major challenge. This is further complicated by the costs usually associated with deploying and testing an application in the cloud. In this paper, we encode the pattern selection problem as a model-based optimization problem to automatically compute good solutions of configured pattern applications. Particularly, we propose a two-phased approach, which is guided by user-defined constraints on the non-functional properties of the application. In the first phase, a preliminary set of promising solutions is computed using a genetic algorithm. In the second phase, this set of solutions is evaluated in more detail using model simulation. We demonstrate the proposed approach and show its feasibility by an initial case study.European Commission ICT Policy Support Programme 31785

Heavy Quark Fragmentation to Baryons Containing Two Heavy Quarks

We discuss the fragmentation of a heavy quark to a baryon containing two heavy quarks of mass $m_Q\gg\Lambda_{\rm QCD}$. In this limit the heavy quarks first combine perturbatively into a compact diquark with a radius small compared to $1/\Lambda_{\rm QCD}$, which interacts with the light hadronic degrees of freedom exactly as does a heavy antiquark. The subsequent evolution of this $QQ$ diquark to a $QQq$ baryon is identical to the fragmentation of a heavy antiquark to a meson. We apply this analysis to the production of baryons of the form $ccq$, $bbq$, and $bcq$.Comment: 9 pages, 1 figure included, uses harvmac.tex and epsf.tex, UCSD/PTH 93-11, CALT-68-1868, SLAC-PUB-622