Search results for "ESTIMATION"

Analysing Buyers' Burstiness in E-Business: Parameter Estimation and Practical Applications

2017

Racecar Longitudinal Control in Unknown and Highly-Varying Driving Conditions

2020

This paper focuses on racecar longitudinal control with highly-varying driving conditions. The main factors affecting the dynamic behavior of a vehicle, including aerodynamic forces, wheel rolling resistance, traction force resulting from changing tire-road interaction as well as the occurrence of sudden wind gusts or the presence of persistent winds, are considered and assumed to have unknown models. By exploiting the theory on delayed input-state observers and using measurement data about the vehicle and wheel speeds, a dynamic filter that allows the online reconstruction of the above-mentioned unknown time-varying quantities is derived. Moreover, by exploiting the notion of effective tir…

Product and Labour Market Regulations, Production Prices, Wages and Productivity

2016

ACLN; International audience; This study is an attempt to evaluate the effects of product and labour market regulations on industry productivity through their various impacts on changes in production prices and wages. In a first stage, the estimation of a regression equation on an industry*country panel, with controls for country*industry and country*year fixed effects, show that multi-factor productivity is negatively and significantly influenced by both indicators of industrial prices from same industry and weighted average of industrial prices from other industries, and by indicators of country wages weighted by industry labour shares for low and high skilled workers. In a second stage, …

SMEs' Growth Heterogeneity - Evidence from Regional Developments

2014

Previous empirical research on small and medium-sized enterprises (SMEs) frequently struggled with the extreme heterogeneity of these frms. We scrutinise one major source of this heterogeneity: SMEs' growth development. Based on a large dataset of French, Italian, UK and US firms between 2000 and 2008, we find that SMEs fall in two categories in all countries: One large group of firms that display only slow growth and one much smaller group that actively seek strong growth. We show that the growth factors particularly of the slowly-growing firms vary strongly between the countries. European SMEs differ mainly in the growth effects of their ownership structures. US firms set themselves apart…

Free Energy, Enthalpy and Entropy from Implicit Solvent End-Point Simulations

2018

Free energy is the key quantity to describe the thermodynamics of biological systems. In this perspective we consider the calculation of free energy, enthalpy and entropy from end-point molecular dynamics simulations. Since the enthalpy may be calculated as the ensemble average over equilibrated simulation snapshots the difficulties related to free energy calculation are ultimately related to the calculation of the entropy of the system and in particular of the solvent entropy. In the last two decades implicit solvent models have been used to circumvent the problem and to take into account solvent entropy implicitly in the solvation terms. More recently outstanding advancement in both impli…

Assessing the feasibility of cogeneration retrofit and district heating/cooling networks in small Italian islands

2017

Sustainability of energy supply strategies in small islands has been emerging as a severe issue, due to the large margins for improvement and rationalization of the most frequently adopted solutions. In most of the European islands, large amounts of heat are wasted by the operation of engine-based power plants; conversely, heat is produced by boilers (supplied by liquid fuels) or by electric equipment for a number of different uses, like domestic hot water production or space heating in winter. In this paper a techno-economic analysis is proposed to assess the feasibility of CHP-retrofit of the existing power plants and the possible utilization of the recovered heat to supply, via a distric…

Proof of Concept of an Irradiance Estimation System for Reconfigurable Photovoltaic Arrays

2015

In order to reduce the mismatch effect caused by non-uniform shadows in PV arrays, reconfigurable interconnections approaches have been recently proposed in the literature. These systems usually require the knowledge of the solar radiation affecting every solar module. The aim of this work is to evaluate the effectiveness of three irradiance estimation approaches in order to define which can be well suited for reconfigurable PV arrays. It is presented a real-time solar irradiance estimation device (IrradEst), implementing the three different estimation methods. The proposed system is based on mathematical models of PV modules enabling to estimate irradiation values by sensing a combination …

Speed and rotor flux estimation of induction motors via on-line adjusted extended kalman filter

2006

This paper deals with the estimation of speed and rotor flux of induction motors via Extended Kalman Filter (EKF) with on-line adjusting of the system noise covariance matrix. The predictor of EKF consists of a discrete time model obtained by means of a second order discretization of the original nonlinear model of the induction motor. In order to obtain accurate estimation of the above mentioned variables, the load torque is included in the state variables and then estimated. Three different system noise models are also illustrated and compared each other by simulations carried out in Matlab/Simulink environment. For one of these models, EKF is adjusted on-line by means of an additional PI…

Sensorless low Range Speed Estimation and Parameter Identification of Induction Motor Drives Devoted to Lifts Automatic Rescue Devices

2010

In this paper a sensorless rotor speed estimation and parameter identification algorithm is presented. The algorithm is designed specifically for induction motor (IM) drives devoted to automatic rescue devices (ARD) used in lifts and hoist applications. Its peculiarity is that it is based on the sinusoidal steady state mathematical model of the IM and, therefore, can be implemented on a low cost micro-controller in a simple way, however without lacking in terms of dynamic performance. It is also capable of self tuning so that no information is required about the specific IM used in the ARD drive. Finally the algorithm allows also an appreciable energy saving of the ARD when compared to olde…

Identification of a static tool force model for robotic face milling

2014

In this paper two different process models which can predict the mean value components of the tool forces when milling aluminium, bronze and steel with an industrial robot have been estimated. The parameters in the process models were depth and width of cut, while feedrate and cutting speed were found from the tool manufacturer's datasheets. The models were estimated from a large set of machining experiments. Different measurement sets were used for parameter estimation and for model verification. The estimated models were found to be accurate. For the experiments in aluminium and the model using only the depth of cut as parameter, the average error was about 18N. For the model using both d…