Probability Distributions.- Linear Models for Regression.- Linear Models for Classification.- Neural Networks.- Kernel Methods.- Sparse Kernel Machines.- Graphical Models.- Mixture Models and EM.- Approximate Inference.- Sampling Methods.- Continuous Latent Variables.- Sequential Data.- Combining Models.

Pattern Recognition and Machine Learning

Pattern recognition

Plasma Chemistry: References

Gravitational Search Algorithm (GSA) is an optimization method inspired by the theory of Newtonian gravity in physics. Till now, many variants of GSA have been introduced, most of them are motivated by gravity-related theories such as relativity and astronomy. On the one hand, to solve different kinds of optimization problems, modified versions of GSA have been presented such as continuous (real), binary, discrete, multimodal, constraint, single-objective, and multi-objective GSA. On the other hand, to tackle the difficulties in real-world problems, the efficiency of GSA has been improved using specialized operators, hybridization, local search, and designing the self-adaptive algorithms. Researchers have utilized GSA to solve various engineering optimization problems in diverse fields of applications ranging from electrical engineering to bioinformatics. Here, we discussed a comprehensive investigation of GSA and a brief review of GSA developments in solving different engineering problems to build up a global picture and to open the mind to explore possible applications. We also made a number of suggestions that can be undertaken to help move the area forward.

A comprehensive survey on gravitational search algorithm

http://ieeexplore.ieee.org/iel5/57/17476/00806380.pdf

Outdoor insulators

Currently, 10 MW of wind power generation (WPG) is installed in the isolated Adrar power system in southern Algeria. This new source of energy has a significant influence on dynamic stability and frequency dynamic behavior in insulated power systems. For this reason, this work is devoted to set up a better integration of the WPG on this power system. In the first step, we study the impact of WPG on dynamic behavior of the frequency, we simulate different events by using SICRE platform with and without the presence of WPG. In a second step, we propose a new defense plan for a better response against major disturbances, we simulate the behavior of the power system with the current and the proposed defense plan and we make a comparison.

A better integration of wind power generation in Adrar Algerian insulated power system

Most of the malfunctions of electrical systems inside wind turbine, including the control ones, are related to the ground potential rise of the grounding system resulting from lightning discharge. Indeed, the performance of such systems mainly depends on the lightning current wave propagation characteristics. Large grounding system performance against lightning discharge depends on the current wave propagation characteristics through the grounding system. It is in this light that the paper proposes to analyse and discuss the impulse behaviour of Wind Turbine Grounding System (WTGS). The interconnection effect on the lightning response of WTGS has been investigated for various values of soil resistivities. Also, the paper discusses the feed point effect for typical small wind farm. It is found that the soil resistivity has a significant influence affecting the transient response of WTGS while the interconnection facilitates the flow of the current into the ground. For interconnected systems, it is shown that the injection at the middle wind turbines gives the lower ground potential rise, thus, more suitable results than the other ones. It is suggested that the wind turbines of the middle should be more taller than the other, especially for those installed in areas characterizing by high values of soil resistivity.

/pdf/impulse-analysis-of-isolated-and-interconnected-wtgss-under-495ghod0s5.pdf

Impulse Analysis of Isolated and Interconnected WTGSs under Lightning Discharges

This paper expose a novel algorithm to monitor and classify the pollution severity level of insulators based on Leakage Current (LC) waveforms investigation. For this purpose, LC waveforms acquisition is firstly carried out on a plane insulator model under various saline pollution conductivities. Then, LC is investigated and decomposed in five levels using the Wavelet Packet Transform (WPT). Two, four, eight, sixteen and thirty-two coefficients are obtained from the first level to the fifth one respectively. Next, Standard Deviation-Multi Resolution Analysis (STD-MRA) is used to extract features from WPT coefficients. It is noted that the higher the pollution severity, the higher the STD value. Finally, STD values are used as inputs to three well known classification methods (K-Nearest Neighbors, Naive Bayes and Support Vector Machines), while the sole output is the pollution conductivity value. Results announce that the higher the decomposition level, the better the classification performance. WPT methodology is presented as a highly efficient technique for LC investigation and classification.

Wavelet Packet Transform based Multi Resolution Analysis technique for classification of LC waveforms on polluted insulating surfaces

In this paper, we present a numerical simulation of the influence of water trees growing from semiconducting layers (in the interior and the exterior) in presence or not of space charges on the behavior of the cross-linked polyethylene (XLPE) insulation used in the medium voltage cables. Individual vented tree configurations are modeled under Comsol Multiphysics environment. To understand the mechanism of involved phenomena, an evaluation of the electric field distribution is carried out. The influence parameters adopted in this investigation are: the permittivity, the length of the water trees and the magnitude of the space charges. The results of investigation showed that, in the absence of space charges, water trees lead to a local increase (respectively decrease) of the electric field in the outside (respectively inside) areas of these trees. However, the accumulation of space charges induces a significant variation of electric field inside and outside the trees and in the volume of insulation. In fact, the electric field repartition depends on the magnitude of space charge density and space charge layer dimension. According to this repartition, the dynamic movement of the space charges is evoked.

Effect of magnitude of space charges on the electric field distribution in XLPE insulation in presence of water trees

The present paper aims at investigating the influence of thermal aging on the crystallinity, the permittivity and $\beta$-relaxation of cross-linked polyethylene (XLPE) used in power cables For this, accelerated thermal aging is performed on circular XLPE samples for 5040 h (210 days) at 80, 100 and 120 °C and for 1512 h (63 days) at 140 °C Changes in the crystallinity of XLPE are assessed by Differential Scanning Calorimetry (DSC) Frequency domain dielectric spectroscopy is used to analyze the variations of real and imaginary parts of the permittivity, before and after aging Moreover, $\beta$-relaxation is investigated through loss factor ($\varepsilon_{r}$”) analysis in the temperature range from 0 to 100 °C at several different frequencies 10, 102, 103 and 104 Hz We show that dielectric spectroscopy is not the best suite method to reveal the earlier steps of aging

Madjid Teguar

Papers

A better integration of wind power generation in Adrar Algerian insulated power system

Impulse Analysis of Isolated and Interconnected WTGSs under Lightning Discharges

Wavelet Packet Transform based Multi Resolution Analysis technique for classification of LC waveforms on polluted insulating surfaces

Effect of magnitude of space charges on the electric field distribution in XLPE insulation in presence of water trees

Dielectric Properties and β-Relaxation in Cross-linked Polyethylene: Effect of Thermal Aging