Search results for "Control systems"

Cloud and Fog Effects and Their Parameterisation in Regional Air Quality Models

1997

For the special purpose of cloud chemistry a tool ASOCC was developed which is able to generate a differential equation system from a given set of chemical kinetics equations. Sensitivity and structure analysis have been performed to evaluate the great number of investigated reactions in the liquid phase and to derive a condensed mechanism for use in regional chemistry-transport models.

Iteratively reweighted least squares in crystal structure refinements

2011

The use of robust techniques in crystal structure multipole refinements of small molecules as an alternative to the commonly adopted weighted least squares is presented and discussed. As is well known, the main disadvantage of least-squares fitting is its sensitivity to outliers. The elimination from the data set of the most aberrant reflections (due to both experimental errors and incompleteness of the model) is an effective practice that could yield satisfactory results, but it is often complicated in the presence of a great number of bad data points, whose one-by-one elimination could become unattainable. This problem can be circumvented by means of a robust least-squares regression that…

A mesh less approch based upon Radial basis function Hermite collocation method for predicting the cooling and the freezing times of foods

2005

This work presents a meshless numerical scheme for the solution of time dependent non linear heat transfer problems in terms of a radial basis function Hermite collocation approach. The proposed scheme is applied to foodstuff's samples during freezing process; evaluation of the time evolution of the temperature profile along the sample, as well as at the core, is carried out. The moving phase-change zone is identified in the domain and plotted at several timesteps. The robustness of the proposed scheme is tested by a comparison of the obtained numerical results with those found using a Finite Volume Method and with experimental results.

Dynamic Lighting Strategies with Load Modulation Purposes to Reduce Peak Electrical Demand

2018

This paper proposes a study about the feasibility to modulate the indoor artificial lighting, taking into account both achievable energy savings and comfort conditions, in order to reduce lighting electric loads. In particular, it focuses on the possibility, on one hand, to decrease the luminous flux and, on the other hand, to change the Correlated Colour Temperature (CCT), in order to decrease the absorbed power. Moreover, the impact of daylight-linked control systems was considered. Finally, the possibility to combine the different technical solutions was analysed. The paper proposes the definition of daily scheduling referred to lighting energy management, in order to modulate the maximu…

Automated control systems for indoor lighting: from design to actual performances' assessment

In recent years, but already around 1980, many buildings have been equipped with Building Automation and Control (BAC) systems. These systems were applied as a normal upgrade of traditional systems in different field of the industrial sector. In general, they can be applied to the building plants in order to carry out a series of functions. The main benefits of the installation of this kind of system are well known. First of all, it has been shown that BACs systems installation increases the energy savings and because using many typologies of sensors (e.g. presence detectors to control lighting system) and because, by monitoring the data it is possible to modify plant’s strategies and also …

Influence on the Dynamic Behavior of Full Car Equipped by Magnetorheological Damper via Switch on/off and h∞ Controller

2011

This paper shows the influence on dynamic behavior of the car when it is equipped with magneto-rheological dampers controlled by a feedback. The feedback is built up in two ways; the first is implemented by a switch on/off control that is characterized by the injection of magnetic field with a constant value. It happens when a certain value of relative speed between the sprung and unsprung mass is exceeded. The second feedback is characterized by the H-infinity control which is based on the relative displacement in order to vary the magnetic field signal in a continuous manner. At the same time the H-infinity control of vehicle is maintained by taking into account the exceeding of speed sig…

Modelling and cost analysis of hybrid systems for seawater desalination: Electromembrane pre-treatments for Reverse Osmosis

2019

Abstract The need to reduce energy consumption in seawater Reverse Osmosis (RO) process has pushed research towards the development of new hybrid systems in which, for example, other membrane processes can be used to pre-treat seawater. Electrodialysis (ED) and Reverse Electrodialysis (RED) can act as a pre-desalting step before seawater enters the RO unit, thus leading to an important energy saving in RO. In this work, two coupled models are proposed for the RED-RO and ED-RO systems. Each process model was validated. Then a sensitivity analysis was performed to assess the effect of the integration on the overall process cost saving. The analysis was performed by changing ED or RED voltage …

Non-celiac wheat sensitivity: a search for the pathogenesis of a self-reported condition

2019

A significant percentage of the general population reports gastrointestinal and non-gastrointestinal symptoms caused by wheat and/or gluten ingestion, even though they do not suffer from celiac disease (CD) or wheat allergy (WS), because they test negative both for CD-specific serology and histopathology. All patients report improvement of symptoms on a gluten-free diet. This clinical condition has been named non-celiac gluten sensitivity (NCGS). The objective of this paper was to review some studies regarding the pathogenesis of NCGS to summarize the current hypotheses about the mechanisms, which can lead to NCGS. Particular attention was given to the immunologic and the malabsorptive hypo…

Il controllo di gestione nell’economia delle banche: aspetti definitori e considerazioni sulle prospettive interpretative proposte dalla letteratura …

2016

Il presente lavoro intende prendere in esame la nozione di controllo di gestione nell’economia delle aziende di credito, a partire dei principali contributi delle dottrine economico-aziendali e manageriali. In Economia aziendale, il controllo è inteso come guida, governo, conduzione aziendale secondo linee prestabilite e con l’impiego di determinati supporti. In prospettiva sistemica, i meccanismi operativi che supportano il raggiungimento degli obiettivi economico-finanziari-patrimoniali ricoprono un ruolo di rilievo nell’economia e gestione delle banche; fra questi, i “sistemi di controllo di gestione”, assumono fondamentale importanza per il funzionamento efficace ed efficiente dell’orga…

Causal inference in geosciences with kernel sensitivity maps

2020

Establishing causal relations between random variables from observational data is perhaps the most important challenge in today's Science. In remote sensing and geosciences this is of special relevance to better understand the Earth's system and the complex and elusive interactions between processes. In this paper we explore a framework to derive cause-effect relations from pairs of variables via regression and dependence estimation. We propose to focus on the sensitivity (curvature) of the dependence estimator to account for the asymmetry of the forward and inverse densities of approximation residuals. Results in a large collection of 28 geoscience causal inference problems demonstrate the…