32,227 research outputs found
Achieving QVTO & ATL Interoperability: An Experience Report on the Realization of a QVTO to ATL Computer
With the emergence of a number of model transformation languages the need for interoperability among them increases. The degree at which this interoperability can be achieved between two given languages depends heavily on their paradigms (declarative vs imperative).
Previous studies have indicated that the QVT and ATL languages are compatible. In this paper we study the possibility to compile QVT Operational to the ATL virtual machine. We describe our experience of developing such a compiler. The resulting compiled QVT transformations can run on top of existing ATL tools. Thereby we achieve not only QVT/ATL interoperability but also QVT conformance for the ATL tools as defined in the QVT specification
Scientific investigations into the eutrophication of the Norfolk Broads
The word âBroadsâ is used to describe a series of relatively shallow lakes resulting from the flooding of medieval peat diggings. Broadland is essentially freshwater, but because the rivers have such low gradients the lower reaches are brackish. The influence of tide is particularly apparent on the River Yare; in Norwich 40 km from the sea there is a vertical movement of half a metre at spring tide. This study examines the problems that the broadlands are facing. The problems are basically the progressive loss of aquatic plants, in particular the macro- phytes, animal life, outbreaks of avian botulism, occasional fish kills due to a toxin produced by the blue-green alga Prymesium parvum and the emergence of very heavy algal blooms. The main factor for the deteriation of the Broaslands is the eutrophication resulting from enhanced nutrient inputs, in particular of nitrates and phosphates, from a variety of sources. The most important of these are sewage effluents, agricultural drainage, which includes fertilisers and nutrient rich effluents from piggeries and dairy u
Improving a Modular Verification Technique for Aspect Oriented Programming
As aspect oriented software becomes more popular, there will be more demand for a method of verifying the correctness of the programs. This paper tries to address the verification issue by improving a modular verification technique proposed by Krisnamuhrti et al. The technique has the problem that it can not handle every aspect, which may result in a false awnser. By checking the type of the aspect in advance we can prevent this behavior. The proposed solution also improves some other issues regarding the model-checker
Searches for New Physics in Top Events at the Tevatron
Recent results of searches for new physics in top events at the Tevatron are
presented. In case of CDF three searches are discussed using 6.0 to 8.7 fb^{-1}
of data, with the latter being the final CDF data sample available for this
kind of analysis. CDF carried out a search for Top + jet resonance production,
dark matter production in association with single top and boosted tops. No
signs of new physics are observed and instead upper limits are derived. D{\O}
used 5.3 fb^{-1} of data and searched for a narrow resonance in ttbar
production and a time dependent ttbar cross section, which would reveal a
violation of Lorentz invariance. However, no signs for deviations from Standard
Model are seen and instead upper limits for non-Standard Model contributions
are calculated.Comment: 4 pages, 7 figures, To appear in Proceedings of Moriond QCD 201
A Low-Dimensional Model of Coordinated Eye and Head Movements
Eye and head movement data, were recorded under head fixed and head-free conditions, and compared with theoretical results obtained using a nonlinear model of eye-head coordination. The model explains slow, or pursuit movement correlated closely to target movement, and saccades, or quick phases of eye movement. Eye movement under head-fixed conditions was modeled by an externally forced Duffing equation, whilst properties of head movement are described by a second externally forced Duffing equation with lower eigen frequency. In the more natural, head-free conditions where both eye and head movements are used synergetically to pursue a visual target, the vestibulocular reflex (VOR) is represented by coefficients defining the mutual coupling between these two oscillatory systems. In the present model, the oscillator that models eye movement has an inhibitory influence on head movement; head to eye coupling coefficients are included to model the influence of the VOR mechanism. Individual eye and head movement patterns in different subjects can be adequately modeled by altering the coupling coefficients. In order to adequatcly simulate those changes introduced by microgravity conditions, the coefficients defining eye-head coordination (mutual coupling) must be changed. It may be hypothesized tlmt such changes in the neurovestibular system could introduce the instability in eye-head coordination, which is known to lead to space sickness.Whitehall Foundation (S93-24
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