81,612 research outputs found

    Langevin equation in effective theory of interacting QCD pomerons in the limit of large NcN_c

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    Effective field theory of interacting BFKL pomerons is investigated and Langevin equations for the theory, which arise after the introduction of additional auxiliary field, are obtained. The Langevin equations are considered for the case of interacting BFKL pomerons with both splitting and merging vertexes and for the interaction which includes additional "toy" four pomeron interaction vertex. In the latest case an analogy with the Regge field theory in zero dimensions (RFT-0) was used in order to obtain this "toy" four pomeron interaction vertex. The comparison between the Langevin equations obtained in the frameworks of dipole and RFT approaches is performed, the interpretation of results is given and possible implementation of obtained equations is discussed.Comment: 21 pages, 1 figur

    Extending Geant4 Parallelism with External Libraries (MPI, TBB) and Its Use on HPC Resources

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    With Geant4 Version 10.0, released in December 2013, one of the most widely used Monte-Carlo codes has been ported to take full advantage of multi- and many-core CPUs thanks to the introduction of event-level parallelism via multithreading. In this paper we review recent developments to allow for a better integration of parallel Geant4 jobs with external libraries. We have chosen to develop examples using the popular Intel Threading Building Block (for short TBB) as an alternative parallelization approach to the native Geant4 POSIX. To simplify the scaling of a Geant4 application across nodes on a cluster we are improving the support of MPI in Geant4. In particular it is now possible to run an hybrid MPI/MT application that uses MPI to scale across nodes and MT to scale across cores. %The recent developments allow users to easily implement parallel application resources that scale on a very large number of nodes and cores typical of HPC resources.Comment: conferenc

    The challenges and opportunities of diversity in university settings

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    Culture in Heritage On the Socio-Anthropological Notion of Culture in Current Heritage Discourses

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    The intellectual ‘heritage’ of social anthropology - universalism, cultural relativism and comparative method - is today strongly used as a tool-box by institutions and scholars from other fields. An anthropologically colored concept of culture is employed in UNESCO’s international legal frameworks, in the epistemological foundation and justification of the new academic subject heritage as well as for wider contextualizations of case studies on specific heritage items. While all of these discourses involve a marked universalistic notion of culture, the contribution of our paper is to show the different roles that the anthropological subject, culture, plays in each one of them. (Past; History; Sociology of time; Cultural Heritage; UNESCO

    Abridged Petri Nets

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    A new graphical framework, Abridged Petri Nets (APNs) is introduced for bottom-up modeling of complex stochastic systems. APNs are similar to Stochastic Petri Nets (SPNs) in as much as they both rely on component-based representation of system state space, in contrast to Markov chains that explicitly model the states of an entire system. In both frameworks, so-called tokens (denoted as small circles) represent individual entities comprising the system; however, SPN graphs contain two distinct types of nodes (called places and transitions) with transitions serving the purpose of routing tokens among places. As a result, a pair of place nodes in SPNs can be linked to each other only via a transient stop, a transition node. In contrast, APN graphs link place nodes directly by arcs (transitions), similar to state space diagrams for Markov chains, and separate transition nodes are not needed. Tokens in APN are distinct and have labels that can assume both discrete values ("colors") and continuous values ("ages"), both of which can change during simulation. Component interactions are modeled in APNs using triggers, which are either inhibitors or enablers (the inhibitors' opposites). Hierarchical construction of APNs rely on using stacks (layers) of submodels with automatically matching color policies. As a result, APNs provide at least the same modeling power as SPNs, but, as demonstrated by means of several examples, the resulting models are often more compact and transparent, therefore facilitating more efficient performance evaluation of complex systems.Comment: 17 figure

    Category Theory and Model-Driven Engineering: From Formal Semantics to Design Patterns and Beyond

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    There is a hidden intrigue in the title. CT is one of the most abstract mathematical disciplines, sometimes nicknamed "abstract nonsense". MDE is a recent trend in software development, industrially supported by standards, tools, and the status of a new "silver bullet". Surprisingly, categorical patterns turn out to be directly applicable to mathematical modeling of structures appearing in everyday MDE practice. Model merging, transformation, synchronization, and other important model management scenarios can be seen as executions of categorical specifications. Moreover, the paper aims to elucidate a claim that relationships between CT and MDE are more complex and richer than is normally assumed for "applied mathematics". CT provides a toolbox of design patterns and structural principles of real practical value for MDE. We will present examples of how an elementary categorical arrangement of a model management scenario reveals deficiencies in the architecture of modern tools automating the scenario.Comment: In Proceedings ACCAT 2012, arXiv:1208.430

    Ontology mapping: the state of the art

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    Ontology mapping is seen as a solution provider in today's landscape of ontology research. As the number of ontologies that are made publicly available and accessible on the Web increases steadily, so does the need for applications to use them. A single ontology is no longer enough to support the tasks envisaged by a distributed environment like the Semantic Web. Multiple ontologies need to be accessed from several applications. Mapping could provide a common layer from which several ontologies could be accessed and hence could exchange information in semantically sound manners. Developing such mapping has beeb the focus of a variety of works originating from diverse communities over a number of years. In this article we comprehensively review and present these works. We also provide insights on the pragmatics of ontology mapping and elaborate on a theoretical approach for defining ontology mapping
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