Search results for "modelling"
showing 10 items of 1353 documents
Macroeconomic Modelling in EMU: How Relevant is the Change in Regime?
2007
We analyse the likely effects of changes in the monetary and financial regimes of EMU countries on the dynamics of output and inflation. In particular, we evaluate the impact of the regime shift on the forecasting performance of reduced-form models. Data for both the pre-EMU and the EMU regimes are generated by a relatively standard open-economy-DSGE model with sticky prices and wages and restricted access to financial markets for some individuals. We find that the effects of the shift in the monetary regime on the processes followed by macroeconomic variables depend on the nature of the shocks hitting the economy. For plausible shocks distributions the reduction in the accuracy of VAR-base…
Global sensitivity analysis for urban water quality modelling: comparison of different methods
2012
Sensitivity analysis represents an important step in improving the understanding and use of environmental models. Indeed, by means of global sensitivity analysis (GSA), modellers may identify both important (factor prioritization) and non-influential (factor fixing) model input factors. However, despite the potentialities of GSA methods, only few applications have been published in the field of urban drainage modelling. In order to fill this gap this paper presents a comparison among three GSA methods (SRC, Extended-FAST and Morris screening) on an urban drainage storm-water model. In particular, an exhaustive discussion on their peculiarities, applicability, and reliability is presented. S…
Enterprise content management: An integrated perspective on information management
2005
Konferansebidrag fra 38th Annual Hawaii International Conference on System Sciences, 2005. HICSS 2005 Enterprise Content Management (ECM) is an emerging concept involving numerous software vendors, consultants, and information management practitioners around increasing market potential. However, there exist yet few academic reports on ECM from the viewpoint of organizational system implementations. This article analyses 58, mainly practitioner-oriented, case narratives of ECM projects and implementations to identify a framework of major issues that require managerial attention in organizations. The main areas covered by the framework are: objectives/impacts sought with ECM, enterprise model…
Frequency Domain Information Decomposition: Application to Plateau Waves of Intracranial Pressure
2022
The sustainment and/or resurgence of Plateau Waves (PWs) reveals a borderline cerebral situation of the pressure-volume relationship and is related to increased mortality. The intense systemic stress caused by PWs can be evidenced by the study of Heart Rate Variability (HRV), which is an indicator of the activity of the autonomic nervous system, namely the sympathetic and parasympathetic imbalance. In this work, heart and brain crosstalk interactions will be analyzed using a spectral decomposition of multivariate information measures, which provides frequency-specific quantification of the information shared between a target and two source time series. The spectral measures of information h…
Contribution to the study of spray formation
2012
The work of this thesis aims to provide and validate tools useful to study and understand the phenomena involved in the injection of fuel, mainly focused on intra-flow injector. These tools are numeric and simulate the formation of a spray. A first part focuses on zero-dimensional modelling. Models which predict these following characteristics of spray like the spray angle, the spray penetration or the liquid length are compared with experimental data. The conclusions are that zero-dimensional modelling provides good results very quickly in some cases. Although, a better understanding of the influence of cavitation on the spray, which requires an understanding of the intra-flow injector, co…
Green synthesis of bromine by TiO2 heterogeneous photocatalysis and/or ozone: A kinetic study
2018
Abstract Elemental bromine is an industrially relevant compound traditionally produced from bromide ions by using chlorine as the oxidizing agent. Problems related to transportation and handling of the corrosive, expensive and toxic chlorine make green synthetic alternatives highly desirable. In this paper the green synthesis of bromine from bromide in aqueous solutions under mild conditions by means of TiO2 photocatalysis and/or ozonation has been investigated from a kinetic point of view. The ozonation in the absence of the photocatalyst follows a first order kinetic with respect to both ozone and bromide. The kinetics of the reactions in the presence of the photocatalyst has been describ…
Integrated modelling of the influence of urbanization and climate change on river water quality
2010
Climate change is one of the most important drivers modifying the hydrologic and environmental characteristics of natural catchments. When dealing with the quality of natural waters, these factors should be weighed up against anthropogenic factors that may increase or decrease the effect of climatic modifications. However, a detailed and more generalised analysis of such environmental impacts at a relatively small scale is currently lack. This paper aims to fill this gap. The use of a holistic approach is also required by the EU Water Framework Directive, which prescribes integrated analysis for river basin management in order to meet environmental and ecological objectives. In order to qua…
Assessment of data availability influence on integrated urban drainage modelling uncertainty
2009
In urban water quality management, several models are connected and integrated for analysing the fate of pollutants from the sources in the urban catchment to the final recipient; classical problems connected with the selection and calibration of parameters are amplified by the complexity of the modelling approach increasing their uncertainty. The present paper aims at studying the influence of reductions in available data on the modelling response uncertainty with respect to the different integrated modelling outputs (both considering quantity and quality variables). At this scope, a parsimonious integrated home-made model has been used allowing for analysing the combinative effect of data…
Thermodynamics-based gradient plasticity theories with an application to interface models
2008
AbstractIn the framework of small deformations, the so-called residual-based gradient plasticity theory is reconsidered and improved. Using the notion of moving geometrically necessary dislocations (GNDs), suitable micromechanics interpretations are heuristically given for the higher order boundary conditions and the long distance particle interactions. Also, a comparison is made between this theory and the analogous virtual work principle (VWP)-based one, whereby their respective conceptual and methodological features are pointed out. The conditions under which the two theories lead to a same constitutive model are investigated, showing that, correspondingly, a certain indeterminacy exhibi…
Material Internal Frictional Dissipation Modelling
2009
This presentation is concerned with a first introductory study devoted to internal frictional dissipation modelling of cracked materials. The problem is set as periodic Representative Volume Element (RVE) with oriented cracks diffused in the bulk material. As first stage, useful for moderate loading levels, cracks are considered fixed and stable at certain position and are modelled as perfect frictional mechanical interface with unilateral contact features. Analyses on cyclic material response are discussed for 2D problems. A second type of analyses is performed considering a further cohesion strength and a crack propagation criteria, which are typical of interface damage mechanical approac…