Search results for " MODELLI"

Wait-and-switch relaxation model: Relationship between nonexponential relaxation patterns and random local properties of a complex system

2006

The wait-and-switch stochastic model of relaxation is presented. Using the ``random-variable'' formalism of limit theorems of probability theory we explain the universality of the short- and long-time fractional-power laws in relaxation responses of complex systems. We show that the time evolution of the nonequilibrium state of a macroscopic system depends on two stochastic mechanisms: one, which determines the local statistical properties of the relaxing entities, and the other one, which determines the number (random or deterministic) of the microscopic and mesoscopic relaxation contributions. Within the proposed framework we derive the Havriliak-Negami and Kohlrausch-Williams-Watts funct…

Resistive state relaxation time in ZrO2(Y)-based memristive devices under the influence of external noise

2022

The effects of external digitally synthesized Gaussian noise on the resistive state relaxation time of a ZrO2(Y)-based memristive device when switching from a low resistance state to a high resistance state have been experimentally investigated. A nonmonotonic dependence of the resistive state relaxation time on the external noise intensity is found. This behavior is interpreted as a manifestation of the noise-enhanced stability effect previously observed in various complex systems with metastable states. It is shown that the experimental results agree satisfactorily with the theoretical ones. The presented results indicate the constructive role of external noise and its possible use as a m…

Implementation of non-local boundary layer schemes in the Regional Atmospheric Modeling System and its impact on simulated mesoscale circulations

2016

This paper proposes the implementation of different non-local Planetary Boundary Layer schemes within the Regional Atmospheric Modeling System (RAMS) model. The two selected PBL parameterizations are the Medium-Range Forecast (MRF) PBL and its updated version, known as the Yonsei University (YSU) PBL. YSU is a first-order scheme that uses non-local eddy diffusivity coefficients to compute turbulent fluxes. It is based on the MRF, and improves it with an explicit treatment of the entrainment. With the aim of evaluating the RAMS results for these PBL parameterizations, a series of numerical simulations have been performed and contrasted with the results obtained using the Mellor and Yamada (M…

Data fusion analysis applied to different climate change models: An application to the energy consumptions of a building office

2019

Abstract The paper aims to achieve the modelling of climate change effects on heating and cooling in the building sector, through the use of the available Intergovernmental Panel on Climate Change forecasted data. Data from several different climate models will be fused with regards to mean air temperature, wind speed and horizontal solar radiation. Several climatic models data were analysed ranging from January 2006 to December 2100. Rather than considering each model in isolation, we propose a data fusion approach for providing a robust combined model for morphing an existing weather data file. The final aim is simulating future energy use for heating and cooling of a reference building a…

Traffic induced air pollution modeling: Scenario analysis for air quality management in street canyon

2019

This study was supported by the Riga City research project DMV-17-60-lī-03.02.2017. The authors wish to thank the Riga City Council and Latvian Environment, Geology and Meteorology Centre for data used in this study.

An approximate calculation method for parallel and diffuse solar irradiances on inclined surfaces in the presence of obstructing mountains or buildin…

1983

This paper presents an approximate theoretical method to calculate solar irradiances received by inclined surfaces in mountain valleys or city streets. Results can be used in mesoscale and urban dynamic modelling.

Capability-based Communication Analysis for Enterprise Modelling

2018

Capability-oriented enterprise modelling can provide effective solutions to face changing business context. In the business domain, the notion of capability has gained a lot of attention since it guides the activities of service specification and design. Simultaneously, the research community has been promoting the integration of model-driven development (MDD) approaches with enterprise modelling to support the link between enterprise and software specifications. This integration has becoming vital to ensure the traceability of enterprise models and software implementations, acceleration of software time to market, quality assurance, and enterprise model evolution support. The capability-dr…

Dynamic Portfolio Optimization with Stochastic Programming

2010

Simplified model to evaluate the fate of micropollutants in an integrated urban drainage system: sensitivity analysis

2016

The paper presents the sensitivity analysis of an integrated urban water quality system by means of the global sensitivity analysis (GSA). Specifically, an home-made integrated model developed in previous studies has been modified in order to include the micropollutant assessment (namely, sulfamethoxazole - SMX). The model takes into account also the interactions between the three components of the system: sewer system (SS), wastewater treatment plant (WWTP) and the receiving water body (RWB). The analysis has been applied to an experimental catchment nearby Palermo (Italy): the Nocella catchment. Five scenarios each characterized by different combinations of sub-systems (i.e., SS, WWTP and…

On vortex shape in unbaffled stirred vessels as measured by digital image analysis

2012

In this work, digital image analysis coupled with a suitable shadowgraphy-based technique is employed to investigate the shape of the free-surface vortex that forms in uncovered unbaffled tanks stirred by either a D=T/3 Lightnin A310 or a D=T/3 Rushton turbine. The technique is based on back-lighting the vessel and suitably averaging vortex images over time. Data obtained show that the two different impellers give rise to quite different vortex shapes. A novel 2-parameter model is proposed that successfully describes vortex shapes obtained with both impellers.