Search results for "Modeling"

Characterization of a digital camera as an absolute tristimulus colorimeter

2003

An algorithm is proposed for the spectral and colorimetric characterization of digital still cameras (DSC) which allows them to be used as tele-colorimeters with CIE-XYZ color output, in cd/m2. The spectral characterization consists in the calculation of the color-matching functions from the previously measured spectral sensitivities. The colorimetric characterization consists in trans- forming the raw RGB digital data into absolute tristimulus values CIE-XYZ (in cd/m2) under variable and unknown spectroradiometric conditions. Thus, in the first stage, a gray balance was applied over the raw RGB digital data to convert them into RGB relative colorimetric values. In the second stage, an algo…

Robust technique for 3D shape reconstruction

2017

Abstract In this paper a robust and simple scheme is presented for three dimensional (3D) shape reconstruction of real object. A novel composite pattern technique is proposed for projecting the light pattern on the object of interest. The proposed scheme reduces the number of patterns by combining the primary color coded channels into one composite format. Our approach uses both spatial and temporal intensity variation for calibration and construction phase. Gamma calibration is considered with the propose scheme. High quality depth map is obtained from the linear light reflected by the shape of object without complex calculations. Experimental results demonstrated that proposed technique i…

Using a neural network for qualitative and quantitative predictions of weld integrity in solid bonding dominated processes

2014

Solid-state bonding occurs in several manufacturing processes, as Friction Stir Welding, Porthole Die Extrusion and Roll Bonding. Proper conditions of pressure, temperature, strain and strain rate are needed in order to get effective bonding in the final component. In the paper, a neural network is set up, trained and used to predict the bonding occurrence starting from the results of specific numerical models developed for each process. The Plata-Piwnik criterion was used in order to define a quantitative parameter taking into account the effectiveness of the bonding. Excellent predictive capability of the network is obtained for each process.

Simulation of parasitic effects on Silicon Carbide devices for automotive electric traction

2020

Wide Band Gap (WBG) semiconductors are increasingly addressed towards Electric Vehicle (EV) applications, due to their significant advantages in terms of high-voltage and low-losses performances, suitable for high power applications. Nevertheless, the packaging in WBG devices represents a challenge for designers due to the notable impact that inductive and capacitive parasitic components can bring in high switching frequency regime in terms of noise and power losses. In this paper, a comparison between conventional Silicon (Si) and emerging Silicon-Carbide (SiC) power switching devices is presented. The effects of inductive parasitic effects and switching frequency are investigated in simul…

Finite-element simulation of residual stress induced by split-sleeve cold-expansion process of holes

2008

A three-dimensional finite-element simulation was conducted for a split-sleeve cold-expansion process in order to determine the residual stress field around an expanded hole. The commercial FEA software DEFORM-3D™, a Lagrangian implicit code designed for metal forming processes, was used to model the cold-expansion process of a fastener hole. The results show a through-thickness residual stress field in good agreement with the analytical solution developed by Guo. Moreover, the simulation has highlighted the effect of the split sleeve and the plate thickness on the residual stress field. © 2007 Elsevier B.V. All rights reserved.

Analytical bonding criteria for joint integrity prediction in friction stir welding of aluminum alloys

2014

Abstract In this study, two bonding criteria, previously used for porthole die extrusion, are applied to FSW starting from the local value of the main field variables calculated through a specifically developed 3D numerical model of the process. Their applicability and effectiveness have been assessed through an experimental and numerical campaign carried out with the main process parameters varying in a wide range. The pressure–time–flow criterion was demonstrated to be better suited for FSW processes when large welding speed is used.

Inside c-kit tyrosine kinase: molecular modeling and QSAR in the search of new inhibitors

2010

Integration of physically based distributed hydrological model with model of carbon and nitrogen cycle: Luquillo Critical Zone Observatory, Puerto Ri…

2015

The dynamics of carbon and nitrogen cycles, increasingly influenced by human activities, are the key to the functioning of ecosystems. These cycles are influenced by the composition of the substrate, availability of nitrogen, the population of microorganisms, and by environmental factors. Therefore, land management and use, climate change, and nitrogen deposition patterns influence the dynamics of these macronutrients at the landscape scale. In this work a physically based distributed hydrological model, the tRIBS model, is coupled with a process-based multi-compartment model of the biogeochemical cycle to simulate the dynamics of carbon and nitrogen (CN) in the Mameyes River basin, Puerto …

Organisational and individual resources as antecedents of older nursing professionals’ organisational commitment : Investigating the mediating effect…

2021

Aim and objectives To investigate how organisational and individual resources are linked to older (50+) nursing professionals’ organisational commitment, and to examine the possible mediating role of the active use of selection, optimisation and compensation (SOC) strategies. Background Many healthcare organisations need to find ways to retain their older nursing professionals due to nursing shortage. Design To test a set of hypotheses, cross-sectional survey data (n = 396) were used. Data were analysed using correlation analysis and partial least-squares structural equation modelling. STROBE Statement for cross-sectional studies has been followed in this study. Results The results exhibite…

How Followers Differing in Career Motivation Gain Career Profits from Transformational Leaders: A Longitudinal Moderated Mediation Model

2017

Although, transformational leadership is among the most thoroughly examined leadership theories, knowledge regarding its association with followers' career outcomes is still limited. Furthermore, the underlying mechanisms explaining how transformational leaders affect their employees' career success are yet not well-understood. Based on theoretical assumptions about the processes involved in setting the goal of “making a career,” we propose an indirect effect of transformational leadership on subjective and objective career success via development opportunities that depends on the level of career motivation of employees. We conducted a longitudinal study with two measurement occasions separ…