Search results for " Error."

Automatic EKF tuning for UAS path following in turbulent air

2018

By using two simultaneously working Extended Kalman Filters, a procedure is implemented in order to perform in a fully autonomous way the path following in turbulent air. To guarantee the robustness of the proposed algorithm, an automatic tuning procedure is proposed to determine optimal values of Process and Measurement Noise statistics. Such a procedure is based on both the characteristics of the disturbances and the desired flight path; in particular, a specific performance index is applied to tune filters. In this way control laws are adapted to the flight condition and these lead to an optimal path-following. This research represents an upload of previous papers. It allows eliminating …

A syntax controlled generator of formal language processors

1963

Adaptive PI Control of Bottom Hole Pressure during Oil Well Drilling

2018

Abstract In this paper, we studied the bottom hole pressure (BHP) control in an oil well during drilling. Today marginal wells with narrow pressure windows are frequently being drilled. This requires accurate and precise control to balance the bottom hole pressure between the pore and fracture pressure of the reservoir. This paper presents three control schemes to stabilize the BHP prole, including proportional-integral(PI) control, PI with feed-forward control and adaptive PI with feed-forward control. The proposed schemes are carried out through simulations on a high-fidelity hydraulic drilling simulator for flow rate changes and BHP set-point changes. In fast set-point changes and flow r…

Improvement of Hall Effect Current Transducer Metrological Performances in the Presence of Harmonic Distortion

2010

The performance of Hall effect current transducers (HECTs), under distorted waveform conditions, is usually characterized by means of a frequency response test. In this paper, it was investigated if frequency response is able to correctly evaluate the ratio and the phase errors under distorted conditions. Two HECTs, with the accuracy class level of 1% and 0.5%, respectively, were experimentally characterized under two conditions: 1) sinusoidal excitation with frequencies ranging from 50 to 750 Hz, which is the well-known frequency response test, and 2) nonsinusoidal excitation using fundamental frequency and one harmonic with adjusted amplitude and phase shift. It was found that ratio and p…

Experimental and Numerical Study on the Flow Field and Friction Factor in a Pressurized Corrugated Pipe

2015

An experimental campaign including measurement of pressure drops and velocity profiles was conducted on the pressurized flow in a commercial corrugated pipe. The results show that the empirical graphs suggested by Morris in the fifties may produce inaccurate assessments of the friction factor, in particular, for low Reynolds numbers. The experimental data was then reproduced by means of a numerical model with the large eddy simulation (LES) technique. The friction factor behavior for low and relatively high Reynolds numbers was thus investigated. The numerical simulations were in good agreement with the experimental results, showing the LES suitability to predict the effect of the pipe wall…

Human error contribution to accidents in the manufacturing sector: A structured approach to evaluate the interdependence among performance shaping fa…

2023

Since the 1970s, Human Reliability Analysis (HRA) methods have received a great interest for the quantification of the Human Error Probability (HEP) in Nuclear Power Plants (NPPs). To this purpose, the second-generation HRA methods consider contextual and cognitive factors - named Performance Shaping Factors (PSFs) - that may influence the workers’ performance during tasks execution. Despite the recent extension of HRA methods to different fields, only few studies refer to the manufacturing sector. In addition, the majority of contributions assume the independence among PSFs, which may result in an over or under estimation of HEP. Therefore, the present paper focuses on the manufacturing se…

Detection of Signals in MC–CDMA Using a Novel Iterative Block Decision Feedback Equalizer

2022

This paper presents a technique to mitigate multiple access interference (MAI) in multicarrier code division multiple access (MC-CDMA) wireless communications systems. Although under normal circumstances the MC-CDMA system can achieve high spectral efficiency and resistance towards inter symbol interference (ISI) however when exposed to substantial nonlinear distortion the issue of MAI manifests. Such distortion results when the power amplifiers are driven into saturation or when the transmit signal experiences extreme adverse channel conditions. The proposed technique uses a modified iterative block decision feedback equalizer (IB-DFE) that uses a minimal mean square error (MMSE) receiver …

Localized forms of the LBB condition and a posteriori estimates for incompressible media problems

2018

Abstract The inf–sup (or LBB) condition plays a crucial role in analysis of viscous flow problems and other problems related to incompressible media. In this paper, we deduce localized forms of this condition that contain a collection of local constants associated with subdomains instead of one global constant for the whole domain. Localized forms of the LBB inequality imply estimates of the distance to the set of divergence free fields. We use them and deduce fully computable bounds of the distance between approximate and exact solutions of boundary value problems arising in the theory of viscous incompressible fluids. The estimates are valid for approximations, which satisfy the incompres…

An efficient data model for energy prediction using wireless sensors

2019

International audience; Energy prediction is in high importance for smart homes and smart cities, since it helps reduce power consumption and provides better energy and cost savings. Many algorithms have been used for predicting energy consumption using data collected from Internet of Things (IoT) devices and wireless sensors. In this paper, we propose a system based on Multilayer Perceptron (MLP) to predict energy consumption of a building using collected information (e.g., light energy, day of the week, humidity, temperature, etc.) from a Wireless Sensor Network (WSN). We compare our system against four other classification algorithms, namely: Linear Regression (LR), Support Vector Machin…

NUMERICAL ALGORITHMS

2013

For many systems of differential equations modeling problems in science and engineering, there are natural splittings of the right hand side into two parts, one non-stiff or mildly stiff, and the other one stiff. For such systems implicit-explicit (IMEX) integration combines an explicit scheme for the non-stiff part with an implicit scheme for the stiff part. In a recent series of papers two of the authors (Sandu and Zhang) have developed IMEX GLMs, a family of implicit-explicit schemes based on general linear methods. It has been shown that, due to their high stage order, IMEX GLMs require no additional coupling order conditions, and are not marred by order reduction. This work develops a …