198,096 research outputs found
Republic of Ghana Country Strategy Paper 2012-2016
This report aims to propose a Bank Group's strategy for supporting Ghana's development efforts over the period 2012 -- 2016. Several factors make a new Bank country strategy for Ghana particularly timely at this moment. These include the enormous challenges the country still faces in its development trajectory in spite of its impressive growth in the last decade, the recent adoption by the Government of the "Ghana Shared Growth and Development Agenda" (GSGDA), the promising developments the country is experiencing in its economic prospects, including becoming an oil producer, attracting interest from BRICS, and the recent completion by the Bank and other development partners of a number of key knowledge products. All these combined provides an opportunity for the Bank and Ghana to lay the foundations for a renewed partnership
GRACE at ONE-LOOP: Automatic calculation of 1-loop diagrams in the electroweak theory with gauge parameter independence checks
We describe the main building blocks of a generic automated package for the
calculation of Feynman diagrams. These blocks include the generation and
creation of a model file, the graph generation, the symbolic calculation at an
intermediate level of the Dirac and tensor algebra, implementation of the loop
integrals, the generation of the matrix elements or helicity amplitudes,
methods for the phase space integrations and eventually the event generation.
The report focuses on the fully automated systems for the calculation of
physical processes based on the experience in developing GRACE-loop. As such, a
detailed description of the renormalisation procedure in the Standard Model is
given emphasizing the central role played by the non-linear gauge fixing
conditions for the construction of such automated codes. The need for such
gauges is better appreciated when it comes to devising efficient and powerful
algorithms for the reduction of the tensorial structures of the loop integrals.
A new technique for these reduction algorithms is described. Explicit formulae
for all two-point functions in a generalised non-linear gauge are given,
together with the complete set of counterterms. We also show how infrared
divergences are dealt with in the system. We give a comprehensive presentation
of some systematic test-runs which have been performed at the one-loop level
for a wide variety of two-to-two processes to show the validity of the gauge
check. These cover fermion-fermion scattering, gauge boson scattering into
fermions, gauge bosons and Higgs bosons scattering processes. Comparisons with
existing results on some one-loop computation in the Standard Model show
excellent agreement. We also briefly recount some recent development concerning
the calculation of mutli-leg one-loop corrections.Comment: 131 pages. Manuscript expanded quite substantially with the inclusion
of an overview of automatic systems for the calculation of Feynman diagrams
both at tree-level and one-loop. Other additions include issues of
regularisation, width effects and renormalisation with unstable particles and
reduction of 5- and 6-point functions. This is a preprint version, final
version to appear as a Phys. Re
A graph-based aspect interference detection approach for UML-based aspect-oriented models
Aspect Oriented Modeling (AOM) techniques facilitate separate modeling of concerns and allow for a more flexible composition of these than traditional modeling technique. While this improves the understandability of each submodel, in order to reason about the behavior of the composed system and to detect conflicts among submodels, automated tool support is required. Current techniques for conflict detection among aspects generally have at least one of the following weaknesses. They require to manually model the abstract semantics for each system; or they derive the system semantics from code assuming one specific aspect-oriented language. Defining an extra semantics model for verification bears the risk of inconsistencies between the actual and the verified design; verifying only at implementation level hinders fixng errors in earlier phases. We propose a technique for fully automatic detection of conflicts between aspects at the model level; more specifically, our approach works on UML models with an extension for modeling pointcuts and advice. As back-end we use a graph-based model checker, for which we have defined an operational semantics of UML diagrams, pointcuts and advice. In order to simulate the system, we automatically derive a graph model from the diagrams. The result is another graph, which represents all possible program executions, and which can be verified against a declarative specification of invariants.\ud
To demonstrate our approach, we discuss a UML-based AOM model of the "Crisis Management System" and a possible design and evolution scenario. The complexity of the system makes con°icts among composed aspects hard to detect: already in the case of two simulated aspects, the state space contains 623 di®erent states and 9 different execution paths. Nevertheless, in case the right pruning methods are used, the state-space only grows linearly with the number of aspects; therefore, the automatic analysis scales
New technologies and procurement and negotiation process support
The aim of this work is to present innovative IT solutions which can
be widely applied in the area of procurement processes and accompanying
negotiations, thereby contributing to the assessment of their practical
applicability. Particular attention has been placed on Ariba Networks, a
platform for procurement management.
This work sources the latest literature in this field as well
as research conducted in one of the largest worldwide companies operating
in the Polish market of fast moving consumable goods.Preparation and printing funded by the National Agency for Research and Development under project “Kreator Innowacyjności – wparcie dla Przedsiębiorczości akademickiej
Using Graph Transformations and Graph Abstractions for Software Verification
In this paper we describe our intended approach for the verification of software written in imperative programming languages. We base our approach on model checking of graph transition systems, where each state is a graph and the transitions are specified by graph transformation rules. We believe that graph transformation is a very suitable technique to model the execution semantics of languages with dynamic memory allocation. Furthermore, such representation allows us to investigate the use of graph abstractions, which can mitigate the combinatorial explosion inherent to model checking. In addition to presenting our planned approach, we reason about its feasibility, and, by providing a brief comparison to other existing methods, we highlight the benefits and drawbacks that are expected
DALiuGE: A Graph Execution Framework for Harnessing the Astronomical Data Deluge
The Data Activated Liu Graph Engine - DALiuGE - is an execution framework for
processing large astronomical datasets at a scale required by the Square
Kilometre Array Phase 1 (SKA1). It includes an interface for expressing complex
data reduction pipelines consisting of both data sets and algorithmic
components and an implementation run-time to execute such pipelines on
distributed resources. By mapping the logical view of a pipeline to its
physical realisation, DALiuGE separates the concerns of multiple stakeholders,
allowing them to collectively optimise large-scale data processing solutions in
a coherent manner. The execution in DALiuGE is data-activated, where each
individual data item autonomously triggers the processing on itself. Such
decentralisation also makes the execution framework very scalable and flexible,
supporting pipeline sizes ranging from less than ten tasks running on a laptop
to tens of millions of concurrent tasks on the second fastest supercomputer in
the world. DALiuGE has been used in production for reducing interferometry data
sets from the Karl E. Jansky Very Large Array and the Mingantu Ultrawide
Spectral Radioheliograph; and is being developed as the execution framework
prototype for the Science Data Processor (SDP) consortium of the Square
Kilometre Array (SKA) telescope. This paper presents a technical overview of
DALiuGE and discusses case studies from the CHILES and MUSER projects that use
DALiuGE to execute production pipelines. In a companion paper, we provide
in-depth analysis of DALiuGE's scalability to very large numbers of tasks on
two supercomputing facilities.Comment: 31 pages, 12 figures, currently under review by Astronomy and
Computin
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