3,110 research outputs found
Scalable data abstractions for distributed parallel computations
The ability to express a program as a hierarchical composition of parts is an
essential tool in managing the complexity of software and a key abstraction
this provides is to separate the representation of data from the computation.
Many current parallel programming models use a shared memory model to provide
data abstraction but this doesn't scale well with large numbers of cores due to
non-determinism and access latency. This paper proposes a simple programming
model that allows scalable parallel programs to be expressed with distributed
representations of data and it provides the programmer with the flexibility to
employ shared or distributed styles of data-parallelism where applicable. It is
capable of an efficient implementation, and with the provision of a small set
of primitive capabilities in the hardware, it can be compiled to operate
directly on the hardware, in the same way stack-based allocation operates for
subroutines in sequential machines
Bidirectional Model Transformations in QVT: Semantic Issues and Open Questions
(QVT) standard as applied to the specification of bidirectional transformations between models. We discuss what is meant by bidirectional transformations, and the model-driven development scenarios in which they are needed. We analyse the fundamental requirements on tools which support such transformations, and discuss some semantic issues which arise. We argue that a considerable amount of basic research is needed before suitable tools will be fully realisable, and suggest directions for this future research
A Declarative Language for Preserving Consistency of Multiple Models
Der Einsatz mehrerer Modelle zur Beschreibung eines Softwaresystems birgt oftmals die Herausforderung, diese konsistent zu halten. WĂ€hrend es viel Forschung zur Konsistenzhaltung zweier Modelle gibt, untersuchen nur wenige Arbeiten die Spezifika der Konsistenzhaltung mehrerer Modelle. In dieser Bachelorarbeit wird eine neue Programmiersprache vorgestellt, die es erlaubt, Transformationen zu erstellen, die mehr als zwei Modelle konsistent halten. Die Sprache verwendet ein Zwischen-Metamodell, sodass alle Transformationen zuerst von einem existierenden Modell in das Zwischenmodell und dann erst in die anderen Modelle ausgefĂŒhrt werden.
ZunĂ€chst betrachten wir verschiedene Möglichkeiten, wie Modelle mit ausschlieĂlich binĂ€ren Transformationen konsistent gehalten werden können. Im Weiteren demonstrieren wir Vorteile davon, ein Zwischen-Metamodell in den Konsistenzhaltungsprozess einzufĂŒhren. Im nĂ€chsten Schritt prĂ€sentieren wir die Gemeinsamkeiten-Sprache als eine Möglichkeit der Konsistenzhaltung mittels Zwischen-Metamodellen. Sie ermöglicht Entwicklern, Metaklassen des Zwischen-Metamodells gemeinsam mit deren Attributen und Referenzen zu deklarieren. Die Abbildungen vom Zwischenmodell in die Modelle, die konsistent gehalten werden sollen, und zurĂŒck, können direkt in den Zwischen-Metaklassen, -Attributen und -Referenzen festgelegt werden. Um Logik nicht zu duplizieren, können bidirektionale AusdrĂŒcke fĂŒr die Abbildungen verwendet werden. Die Sprache ist deklarativ und soll auf diese Weise eine hohe Nachvollziehbarkeit der Transformationen ermöglichen.
Wir haben ein prototypische Implementierung der Sprache fĂŒr Vitruvius erstellt, die in Eclipse fĂŒr EMF-Modelle verwendet werden kann. Die Implementierung kann als Machbarkeitsnachweis gesehen werden, eignet sich allerdings noch nicht fĂŒr den Praxiseinsatz. Die Idee, Zwischen-Metamodelle fĂŒr die skalierbare und modulare Konsistenzhaltung mehrerer Modelle einzusetzen, wurde in anderen Arbeiten in realistische Szenarien bereits erfolgreich umgesetzt. Soweit uns bekannt ist, existiert noch kein Ansatz, der es erlaubt, ein Zwischen-Metamodell und die Transformationen fĂŒr dieses in der selben Sprache zu definieren
COEL: A Web-based Chemistry Simulation Framework
The chemical reaction network (CRN) is a widely used formalism to describe
macroscopic behavior of chemical systems. Available tools for CRN modelling and
simulation require local access, installation, and often involve local file
storage, which is susceptible to loss, lacks searchable structure, and does not
support concurrency. Furthermore, simulations are often single-threaded, and
user interfaces are non-trivial to use. Therefore there are significant hurdles
to conducting efficient and collaborative chemical research. In this paper, we
introduce a new enterprise chemistry simulation framework, COEL, which
addresses these issues. COEL is the first web-based framework of its kind. A
visually pleasing and intuitive user interface, simulations that run on a large
computational grid, reliable database storage, and transactional services make
COEL ideal for collaborative research and education. COEL's most prominent
features include ODE-based simulations of chemical reaction networks and
multicompartment reaction networks, with rich options for user interactions
with those networks. COEL provides DNA-strand displacement transformations and
visualization (and is to our knowledge the first CRN framework to do so), GA
optimization of rate constants, expression validation, an application-wide
plotting engine, and SBML/Octave/Matlab export. We also present an overview of
the underlying software and technologies employed and describe the main
architectural decisions driving our development. COEL is available at
http://coel-sim.org for selected research teams only. We plan to provide a part
of COEL's functionality to the general public in the near future.Comment: 23 pages, 12 figures, 1 tabl
The Iray Light Transport Simulation and Rendering System
While ray tracing has become increasingly common and path tracing is well
understood by now, a major challenge lies in crafting an easy-to-use and
efficient system implementing these technologies. Following a purely
physically-based paradigm while still allowing for artistic workflows, the Iray
light transport simulation and rendering system allows for rendering complex
scenes by the push of a button and thus makes accurate light transport
simulation widely available. In this document we discuss the challenges and
implementation choices that follow from our primary design decisions,
demonstrating that such a rendering system can be made a practical, scalable,
and efficient real-world application that has been adopted by various companies
across many fields and is in use by many industry professionals today
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