Search results for " Dynamic"
showing 10 items of 4727 documents
Assessing Transfer Entropy in cardiovascular and respiratory time series: A VARFI approach
2021
In the study of complex biomedical systems represented by multivariate stochastic processes, such as the cardiovascular and respiratory systems, an issue of great relevance is the description of the system dynamics spanning multiple temporal scales. Recently, the quantification of multiscale complexity based on linear parametric models, incorporating autoregressive coefficients and fractional integration, encompassing short term dynamics and long-range correlations, was extended to multivariate time series. Within this Vector AutoRegressive Fractionally Integrated (VARFI) framework formalized for Gaussian processes, in this work we propose to estimate the Transfer Entropy, or equivalently G…
Study of thermoelectric magnetohydrodynamic convection on solute redistribution during laser additive manufacturing
2020
Abstract Melt pools formed in laser additive manufacturing (AM) are subject to large thermal gradients, resulting in the formation of thermoelectric currents due to the Seebeck effect. When in the presence of an external magnetic field, a Lorentz force is formed which drives fluid flow in the melt pool. This Thermoelectric Magnetohydrodynamics (TEMHD) phenomenon, can have a significant impact on the melt pool morphology and can alter the microstructural evolution of the solidification process. By coupling steady-state mesoscopic melt pool calculations to a microscopic solidification model, predictions of the resulting microstructure for multiple deposited layers have been obtained. The resu…
Synthesis and Structure-Affinity Relationships of Spirocyclic Benzopyrans with Exocyclic Amino Moiety
2019
σ1 and/or σ2 receptors play a crucial role in pathological conditions such as pain, neurodegenerative disorders, and cancer. A set of spirocyclic cyclohexanes with diverse O-heterocycles and amino moieties (general structure III) was prepared and pharmacologically evaluated. In structure-activity relationships studies, the σ1 receptor affinity and σ1:σ2 selectivity were correlated with the stereochemistry, the kind and substitution pattern of the O-heterocycle, and the substituents at the exocyclic amino moiety. cis-configured 2-benzopyran cis-11b bearing a methoxy group and a tertiary cyclohexylmethylamino moiety showed the highest σ1 affinity ( Ki = 1.9 nM) of this series of compounds. In…
A Dynamic Analysis of Tourism Determinants in Sicily
2015
This study provides an initial analysis of the key determinants of tourism in Sicily. In doing so, it responds to the general lack of a scientific approach in the study and management of tourism in Sicily. By mixing a gravity approach and system dynamics methodology, the attractiveness of Sicily is examined, taking into account both structural and promotional aspects that might affect tourism demand. The results strongly suggest that the island's natural and cultural resources, the road infrastructure and the urban environment are important determinants of tourism demand in Sicily. The findings may be useful for local authorities involved in the development of tourism, and represent a star…
Regional differences in Italian students' performance: a simulation model
2017
This work presents the first results of a research project seeking to build a simulation model able to reproduce the differences of Italian students’ performance at regional level. A preliminary qualitative cause-and-effect model defines the main variable involved in the inter-generational skill formation processes, as well as their interplay with the job market context and the triggering of motivational forces for new skill acquisition. Such model was designed according to a system dynamics perspective, considered suitable for capturing the interrelatedness of key variables and for providing useful simulation tools to conduct and communicate future scenario analyses. Keywords: regional…
Evaluation of asset replacement strategies considering economic cycles: lessons from the machinery rental business
2015
Contains fulltext : 144492.pdf (Publisher’s version ) (Open Access) In businesses with heavy capital investments, the effective management of assets is crucial, in particular in the fleet rental business where assets are the major source of revenues. One important question in this regard concerns the replacement of used assets and the purchase of new assets. Thus, the objective of this study is to evaluate performance effects of asset replacement strategies. In order to maximise net cash flow of a rental company for construction machinery, a range of scenarios investigating the timing and nature of policies for replacing the fleet are analysed. Simulation findings are then discussed to gene…
Modelling and assessing public health policies to counteract Italian measles outbreaks
2021
This study aims to understand, through explanatory research, the key factors that led to the 2017 measles outbreak in Italy, the causes of the low level of immunisation and the causes of possible cyclical phenomena of measles epidemics. This topic's comprehension has required a holistic approach, merging epidemiological aspects, socioeconomic aspects (including the evolution of mistrust in vaccinations, infodemy and fake news) and health law constraints. A specific SIR System Dynamics (SD) model was built to reproduce the relevant cause-and-effect relationships between social interactions, the public institutions behaviour and the measles outbreaks. SD results permit the assessment of the h…
Crowdsourcing as a mode of open innovation: Exploring drivers of success of a multisided platform through system dynamics modelling
2020
This article aims to explore drivers of success of a crowdsourcing platform. The study conceptualizes crowdsourcing as a mode of open innovation and places such a concept within the context of the sharing economy. Upon this framework, the paper analyses the case of InnoCentive, a successful crowdsourcing platform where innovation-driven organizations search for solutions to their R&D tasks. The system dynamics model frames main InnoCentive business processes and offers a causal perspective on the relationships between platform performance—in terms of users base—and resources structure. The discussion on simulation outputs is carried out through a dynamic performance management view of p…
Performance Management in Local Government: The Application of System Dynamics to Promote Data Use
2014
The purpose of this article is to demonstrate how system dynamics can be used to enrich performance management in local government, focusing specifically on how the development of conceptual and simulation system dynamic models can foster a shared view of the relevant system among stakeholders to overcome factors that limit data use. Responding to this purpose, we present a normative case study on how key drivers can be used to foster a shared view of the residential refuse collection system for supporting policy and process changes. A major finding from our research, however, is that performance management cannot overlook the broader forces of citizenship outcomes that impact the community.
Business model scaling and growth hacking in digital entrepreneurship
2023
Creating an innovative product and validating an innovative business model may not be enough for digital startups to be competitive. To grow fast and expand globally, digital startups need to innovate their business model during the scaling phase. A pragmatic approach has recently been proposed to support digital entrepreneurs engaging in business-model innovation during the scaling phase (i.e., business-model scaling), a strategy known as growth hacking. However, we know little about its theoretical grounding and how effective growth hacking is, as businesses lack methodologies to assess its effectiveness before committing resources and investments. To fill this gap, we developed a method …