Search results for "modelling"

Applying System Dynamics Modelling to Strategic Management: A Literature Review

2016

System dynamics (SD) has been proved to be a useful methodology to support both understanding and learning processes of complex systems and phenomena. Since its origin, SD has been successfully applied to many different fields of studies (e.g. climate change, physics, engineering, environmental sciences, economics, management, etc.). Among these, strategic management (SM) has a particular relevance as testified by several streams of research that originate from the combination between SD modelling and SM. The aim of this paper is to explore and discuss the theoretical and empirical development of SD in the SM field through a systematic analysis of the literature in order to highlight the ma…

A stochastic dynamic model to evaluate the influence of economy and well-being on unemployment control

2018

[EN] This paper presents a stochastic dynamic mathematical model to study the evolution of the unemployment rate and other relevant related variables in a country. This model is composed by three basic interrelated subsystems: demographic, economic and wellbeing ones. A key aspect of this model is that it considers three UN well-being variables simultaneously: Human Development Index, Gender Empowerment Index and Gender Differentiation Index. These variables involve key concepts for human development, as Health, Education, Economy and Female Labor. With this model, the most outstanding variables found in the literature in relation with unemployment control can be used to design strategies a…

The influence of strain localisation on the rotation behaviour of rigid objects in experimental shear zones

2002

Abstract Mica fish and tourmaline fish from natural mylonites were analysed in thin section to determine their orientation distribution. They are oriented with their long axes tilted with respect to the mylonitic foliation, and fish with a small aspect ratio exhibit a slightly larger angle than fish with a large aspect ratio. This orientation seems to be a stable orientation for the mica and tourmaline fish. Analogue experiments with two rheologically different matrix materials were performed to explain the data. One material was PDMS, a linear viscous polymer. The other was tapioca pearls, a granular material with low cohesion and Mohr–Coulomb type behaviour. In contrast to a fairly homoge…

Application of Mathematical Models in Analysis of Heat Losses in the Buildings

2006

Physical model of heat balance for separate living room is discussed, which allows to analyse the distributions of the flow of air and temperature depending on the physical conditions and geometry. The model enables to choose the optimal surface area of building elements and their properties in order to decrease the heat losses and improve the conditions of thermal comfort. Room with bounding constructions and real dimensions is modelled that helps to understand the peculiarities of heat transfer process in the room as well as distribution of various characteristic quantities and their dependence on the different conditions. Multiple parameters are varied in 2D calculations and their influe…

Understanding disease mechanisms with models of signaling pathway activities

2014

Background Understanding the aspects of the cell functionality that account for disease or drug action mechanisms is one of the main challenges in the analysis of genomic data and is on the basis of the future implementation of precision medicine. Results Here we propose a simple probabilistic model in which signaling pathways are separated into elementary sub-pathways or signal transmission circuits (which ultimately trigger cell functions) and then transforms gene expression measurements into probabilities of activation of such signal transmission circuits. Using this model, differential activation of such circuits between biological conditions can be estimated. Thus, circuit activation s…

Riedel-shear control on the development of pennant veins: Field example and analogue modelling

2006

Abstract The wall rocks of a crustal scale sinistral ductile shear zone in Namibia, the Purros Mylonite Zone, contain two types of asymmetric quartz veins. Bedding surfaces contain sigmoidal quartz veins with limited thickness along their symmetry axes that can be classified as tension gashes. A second type of veins consists of a striated central fault vein separating pennant-type quartz filled terminations. The tips of these “pennant veins” have a different orientation to those of the tension gashes. Analogue experiments were carried out using a sheet of silicone powder suspended on a slab of poly-dimethyl-siloxane (PDMS), both deformed in simple shear. These experiments produced open frac…

River water quality modelling: a parsimonious model approach

2009

Biological Nutrient Removal Model No. 2 (BNRM2): a general model for wastewater treatment plants

2013

This paper presents the plant-wide model Biological Nutrient Removal Model No. 2 (BNRM2). Since nitrite was not considered in the BNRM1, and this previous model also failed to accurately simulate the anaerobic digestion because precipitation processes were not considered, an extension of BNRM1 has been developed. This extension comprises all the components and processes required to simulate nitrogen removal via nitrite and the formation of the solids most likely to precipitate in anaerobic digesters. The solids considered in BNRM2 are: struvite, amorphous calcium phosphate, hidroxyapatite, newberite, vivianite, strengite, variscite, and calcium carbonate. With regard to nitrogen removal via…

L’algoritmo come strumento didattico in fisica: modellizzazione dei gas ideali classici e quantistici

2011

Viene discussa una procedura per la modellizzazione dei gas ideali quantistici. Inoltre, viene evidenziata l’importanza di supportare le incomplete rappresentazioni mentali degli studenti, in relazione ad argomenti complessi di meccanica statistica e termodinamica, con accurati modelli fisici aventi validità predittiva e fondati sull’ipotesi di possibili meccanismi di funzionamento. L’idea alla base dell’approccio proposto è quella che, in alcuni casi, anche la sola discussione dei risultati di un algoritmo o di un modello può essere sufficiente a migliorare la comprensione di un sistema fisico particolarmente complesso.

A new expression of the slope length factor to apply USLE-MM at Sparacia experimental area (Southern Italy)

2013

Abstract Predicting soil loss due to water erosion by empirical models is useful to assess the severity of the phenomenon in an area of interest and to predict the effect of alternative soil erosion control practices. The USLE scheme cannot be used at the Sparacia experimental area (Sicily, South Italy) to predict event soil loss per unit plot area, Ae, because experimental data suggest that, generally, Ae does not increase with plot length, λ. The USLE-MM scheme uses the runoff coefficient, QR, as an additional independent variable in order to develop an empirical model allowing prediction of storm soil loss values that do not necessarily increase with λ. According to this model, Ae is exp…