Search results for " modelling"
showing 10 items of 1055 documents
Stochastic 0-dimensional Biogeochemical Flux Model: Effect of temperature fluctuations on the dynamics of the biogeochemical properties in a marine e…
2021
Abstract We present a new stochastic model, based on a 0-dimensional version of the well known biogeochemical flux model (BFM), which allows to take into account the temperature random fluctuations present in natural systems and therefore to describe more realistically the dynamics of real marine ecosystems. The study presents a detailed analysis of the effects of randomly varying temperature on the lower trophic levels of the food web and ocean biogeochemical processes. More in detail, the temperature is described as a stochastic process driven by an additive self-correlated Gaussian noise. Varying both correlation time and intensity of the noise source, the predominance of different plank…
Ability of software SWMM to simulate sewer smooth pressurization transient
2010
As a consequence of heavy rainfall events or network malfunctioning, filling of sewers (pressurization) and network overflowing may occur. Several models are commonly used to simulate floods in drainage networks and their results are usually thought to be reliable and robust. Actually, mathematical models based on the momentum equation appear to be more suitable in correctly simulating the pressurization moving jump but models based on the energy equation are much more popular because of their greater simplicity in comparison to the former ones. In this paper, on the basis of laboratory pipe tests, the ability of software SWMM (Storm Water Management Model, probably the most popular softwar…
SPH NUMERICAL MODELLING OF WAVE-STRUCTURE INTERACTION
The present thesis aims at contributing to a better understanding and modelling of flow driven by wave propagation approaching artificial or natural structures. From a physical point of view, a simplistic descrip- tion of the interaction of sea waves with a coastal structure can be given as the result of all processes felt by the waves which, propagating from offshore to nearshore, impact on the structure itself. Indeed, as sea waves approach a shore, the motion they generate deep down begins to interact with the sea bed. This slows the waves down and causes the crests in a series of waves to bunch up; this effect is called shoaling. The period of the waves does not change, but their height…
Differentiating Malignant from Benign Pigmented or Non-Pigmented Skin Tumours—A Pilot Study on 3D Hyperspectral Imaging of Complex Skin Surfaces and …
2022
Several optical imaging techniques have been developed to ease the burden of skin cancer disease on our health care system. Hyperspectral images can be used to identify biological tissues by their diffuse reflected spectra. In this second part of a three-phase pilot study, we used a novel hand-held SICSURFIS Spectral Imager with an adaptable field of view and target-wise selectable wavelength channels to provide detailed spectral and spatial data for lesions on complex surfaces. The hyperspectral images (33 wavelengths, 477–891 nm) provided photometric data through individually controlled illumination modules, enabling convolutional networks to utilise spectral, spatial, and skin-surface mo…
Comparison of genetic risk prediction models to improve prediction of coronary heart disease in two large cohorts of the MONICA/KORA study
2021
Abstract It is still unclear how genetic information, provided as single‐nucleotide polymorphisms (SNPs), can be most effectively integrated into risk prediction models for coronary heart disease (CHD) to add significant predictive value beyond clinical risk models. For the present study, a population‐based case‐cohort was used as a trainingset (451 incident cases, 1488 noncases) and an independent cohort as testset (160 incident cases, 2749 noncases). The following strategies to quantify genetic information were compared: A weighted genetic risk score including Metabochip SNPs associated with CHD in the literature (GRSMetabo); selection of the most predictive SNPs among these literature‐co…
Modeling Changes for SHOIN(D) Ontologies: An Exhaustive Structural Model
2013
Ontology development starts with a rigorous ontological analysis that provides a conceptualization of the domain to model agreed by the community. An ontology, specified in a formal language, approximates the intended models of this conceptualization. It needs then to be revised and refined until an ontological commitment is found. Also ulterior updates, responding to changes in the domain and/or the conceptualization, are expected to occur throughout the ontology life cycle. To handle a consistent application of changes, a couple of ontology evolution methodologies have been proposed. Maintaining the structural consistency is one of the ontology evolution criteria. It implies modeling chan…
Improving efficiency and discharge power of acid-base flow battery via a bi-objective optimisation
2023
Modelling and optimization of a passive structural control design for a spar-type floating wind turbine
2014
Abstract Compared with fixed-bottom installation, deep water floating wind turbine has to undergo more severe structural loads due to extra degrees of freedom. Aiming for effective load reduction, this paper deals with the evaluation of a passive structural control design for a spar-type floating wind turbine, and the proposed strategy is to install a tuned mass damper (TMD) into the spar platform. Firstly, a mathematical model for wind turbine surge-heave-pitch motion is established based on the D’Alembert’s principle of inertial forces. Then, parameter estimation is performed by comparing the outputs from the proposed model and the state-of-the-art simulator. Further, different optimizati…
Engaged managers are not workaholics: Evidence from a longitudinal personcentered analysis
2013
El objetivo de este estudio longitudinal entre directivos finlandeses ( n = 463) fue doble: en primer lugar investigar la relación entre el engagement (E) y la adicción al trabajo (AT) mediante enfoques centrados en la persona y en la variable y, en segundo lugar, explorar si (y cómo) se relacionan las experiencias de engagement y la adicción al trabajo con el cambio de trabajo durante el período de estudio. El análisis centrado en las variables, basado en modelos de ecuaciones estructurales, mostró que los factores latentes del engagement y la adicción al mismo no correlacionan entre sí, lo que sugiere que son constructos independien- tes. Los análisis centrados en la persona indicaron cua…
A person-centred approach to investigate the development trajectories of job-related affective well-being: A 10-year follow-up study
2011
The primary aim of this three-wave 10-year follow-up study was to investigate the intra-individual change trajectories of job-related affective well-being among Finnish managers (n = 402). Job-related affective well-being as indicated by anxiety, depression, comfort, and enthusiasm was measured in 1996, 1999, and 2006. The characteristics of the trajectories were sought from experienced career disruptions (i.e., periods of unemployment or lay-offs) and perceived job insecurity. The growth mixture modelling (GMM) revealed altogether three latent trajectories that differed from each other in their mean levels and regard to changes in job-related affective well-being over time: (1) high and im…