Time filter

Source Type

Hamrita M.E.,Higher Institute of Applied science and Technology | Mabrouk A.B.,University of Monastir
International Journal of Wavelets, Multiresolution and Information Processing | Year: 2011

Scaling laws and generally self-similar structures are now well known facts in financial time series. Furthermore, these signals are characterized by the presence of stochastic behavior allowing their analysis with pure functional methods being incomplete. In the present paper, some existing models are reviewed and modified, based on wavelet theory and self-similarity, to recover multi-scaling cases for approximating financial signals. The resulting models are then tested on some empirical examples and analyzed for error estimates. © 2011 World Scientific Publishing Company.


Ben Salah C.,University of Sfax | Ben Mabrouk A.,Higher Institute of Applied science and Technology | Ouali M.,University of Sfax
International Multi-Conference on Systems, Signals and Devices, SSD'11 - Summary Proceedings | Year: 2011

In this paper wavelet decomposition is combined with autoregressive models to analyze and predict climate time series such as solar radiation and photovoltaic cell temperature. The method is tested on climate parameters for analysis, and solar radiation and cell temperature for prediction. The work effectiveness is evaluated by the prediction of the electric energy produced by a 100 Wp photovoltaic panel. Finally, the performance of predictor is measured by standardized error. © 2011 IEEE.


Assar S.,TELECOM Business School | Assar S.,Paris-Sorbonne University | Assar S.,Higher Institute of Applied Science and Technology | Souveyet C.,TELECOM Business School | And 5 more authors.
Proceedings - International Computer Software and Applications Conference | Year: 2012

Goal modeling is a prominent design paradigm in various domains of information systems engineering. In the field of service oriented computing (SOC) and in the field of semantic web services, emergent research works are basing their engineering approach on the goal concept. Because of the complexity of processes underlying SOC, the usage of the goal concept can vary to a large extent. In this paper, we study approaches to service oriented engineering and propose a framework to analyze and better understand how the goal concept is used in web service discovery. The framework is inspired by the four world vision of information systems engineering (i.e. subject, system, development and usage). Using this framework, we review eight prominent research works in SOE. Through this analysis, we seek to better understand the link between semantic web technologies and the goal concept, and what are the challenging issues in terms of goal usage in service discovery. © 2012 IEEE.


Messai S.,Higher Institute of Applied science and Technology | Ganaoui M.E.,Institut Universitaire de France | Sghaier J.,University of Tunis | Belghith A.,University of Tunis
Thermal Science | Year: 2014

An experimental study to evaluate the convective heat transfer coefficient in a cylindrical packed bed of spherical porous alumina particles is investigated. The task consists in proposing a semi-empirical model to avoid excessive instrumentation and time consumption. The measurement of the bed temperature associated to a simple energy balances led to calculate the gas to particle heat transfer coefficient using a logarithmic mean temperature difference method. These experiments were performed at atmospheric pressure. The operating fluid is humid air. The gas velocity and temperature ranged from 1.7-3 m/s and 120-158 °C, respectively. The data obtained was compared with the correlations reported in the literature. It is shown that the proposed model is in reasonable agreement with the correlation of Ranz and Marshall. Despite, many researches on experimental investigations of heat transfer coefficient in packed beds at low and average temperature are proposed, few studies presented calculation of convective heat transfer coefficient at high temperature (above 120 °C). A possible application of the proposed model is drying and combustion.


Saidi S.,University of Tunis | Saidi S.,University of Carthage | Ben Radhia R.,University of Tunis | Ben Radhia R.,Gafsa University | And 4 more authors.
Desalination and Water Treatment | Year: 2014

The present study investigated the experimentation of an inclined solar film evaporator in the meteorological conditions of the town of Bizerte, in Tunisia. The experimental device used in this study has a parallelepiped form. It is primarily constituted by an inclined metal plane plate. A water film falls on the external face of this plate through a porous tissue. A glass cover, placed on a wooden frame put on the plate, is exposed to the solar radiation acting as a solar panel. An ascending air flow enters in the evaporator where it is in direct contact with the falling water film. This experimental device is designed and supplemented by a protocol of measurements to conduct this study. The thermocouples installed along the metal plate were connected to an automatic acquisition making it possible to read and store the measured temperatures values. The evaporated flow is measured by an electronic balance and a stopwatch. The humidity and the air velocities are measured using a digital multifunction device. The series of measurement are carried out in natural and forced convections. The profile of the liquid film temperature and the variation of the evaporated flow are measured for the two convection modes. To quantify the effectiveness of the solar evaporator, the thermal and mass yields are calculated. The results show that the evaporated flow is more significant in forced convection and that the thermal and mass yields of the solar evaporator are higher than 80%. © 2014 Balaban Desalination Publications. All rights reserved.


Blaiech H.,University of Monastir | Sayadi F.E.,Higher Institute of Applied Science and Technology | Tourki R.,University of Monastir
Proceedings of the 2011 International Conference on Image Processing, Computer Vision, and Pattern Recognition, IPCV 2011 | Year: 2011

This paper presents a hardware implementation of face and eyes detection algorithm. To become we must go through several stages. First we have implemented an algorithm for detecting and tracking eyes written in C using an open source library of image processing and computer vision the "OpenCV". Then a profiling on HW/SW (hardware/software) partition was done. The hardware part solves the part of the algorithm with higher computational costs. The system has been implemented on SpartaniA DSP FPGA board. In order to visualize the results on real images, we have made a co-simulation of this bloc using the Simulink tool of Matlab.


Abroug I.,Higher Institute of Applied science and Technology | Abroug I.,University of Sousse | Essoukri Ben Amara N.,University of Sousse | Essoukri Ben Amara N.,University of Monastir
12th International Multi-Conference on Systems, Signals and Devices, SSD 2015 | Year: 2015

In this paper we present an approach of face recognition by using a planar multi-classifier modelling based on neural networks. Each class of the database has been modelled by a PMCM-NN/NN formed by three secondary models and a main one - of an MLP type. We have retained the same characteristics and database used in [2]. The various experiments have been proven on a FERET face database. The recorded results have shown the contribution of our proposed concepts for the generalization of planar models, initially based on HMMs, to other types of classifiers - neural in this case. The validation of the PMCM in the case of face recognition shows results that are very promising and better than those registered in [2]. © 2015 IEEE.


Chamieh M.,Damascus University | El-Kouatly R.,Damascus University | Abu-Amsha O.,Higher Institute of Applied Science and Technology
International Journal of Simulation: Systems, Science and Technology | Year: 2012

In order to introduce a realistic simulation environment to support the research on vehicular Ad hoc Networks (VANETs), the human behavior must be studied, understood and included in the mobility model representing the vehicles movement. This paper studies the behavior of the driver concerning specifically the decision to change the lane. Our study is based on real world observations and safety driving rules, and introduces a new lane-changing simulator accordingly. This simulator is integrated within Intelligent Driver Model with Intersection Management (IDM-IM) and compared with Intelligent Driver Model with Lane Changes (IDM-LC) as well as IDM-IM mobility models provided by VanetMobiSim framework, concerning their effects on the performance of Ad hoc On Demand Routing Protocol (AODV) and reality imitation.


Alshami B.,Damascus University | Aboulnour H.,Damascus University | Dib M.,Higher Institute of Applied science and Technology
2010 10th Mediterranean Microwave Symposium, MMS 2010 | Year: 2010

The implementation and field test of a BroadBand Electrically Steerable Parasitic Array Radiator (BB-ESPAR) antenna [1], as well as a comparison between experimental and simulation results are presented in this paper. BB-ESPAR antenna was modeled, implemented and experimentally characterized. A prototype of the proposed antenna has experimentally produced a horizontal directivity of 8 dBi gain and VSWR less then 3:1 value in the frequency band [465 - 700] MHz. Experimental and simulation results showed a good agreement. © 2010 IEEE.


Saadaoui F.,Higher Institute of Applied science and Technology | Rabbouch H.,National School in Computer Science
Expert Systems with Applications | Year: 2014

The paper proposes a parsimonious nonlinear framework for modeling bivariate stochastic processes. The method is a vector autoregressive-like approach equipped with a wavelet-based feedforward neural network, allowing practitioners dealing with extremely random two-dimensional information to make predictions and plan their future more and more precisely. Artificial Neural Networks (ANN) are recognized as powerful computing devices and universal approximators that proved valuable for a wide range of univariate time series problems. We expand their coverage to handle nonlinear bivariate data. Wavelet techniques are used to strengthen the procedure, since they allow to break up processes information into a finite number of sub-signals, and subsequently extract microscopic patterns in both time and frequency fields. The proposed model can be very valuable especially when modeling nonlinear econophysical systems with high extent of volatility. © 2014 Elsevier Ltd. All rights reserved.

Loading Higher Institute of Applied Science and Technology collaborators
Loading Higher Institute of Applied Science and Technology collaborators