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Search Results: 1 - 10 of 64 matches for " Nesrine Fahem "
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Predictive Factors of Multiple Hospitalizations for Acute Exacerbations of COPD  [PDF]
Ahmed Ben Saad, Nesrine Fahem, Asma Migaou, Saousen Cheikh Mhamed, Samah Joobeur, Naceur Rouatbi
Open Journal of Respiratory Diseases (OJRD) , 2019, DOI: 10.4236/ojrd.2019.93006
Abstract: Background: Multiple hospitalizations for acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are associated with considerable morbidity and mortality. Objectives: To identify predictive factors of multiples hospitalizations for AECOPD. Methods: This is a retrospective single center study of consecutive patients with COPD hospitalized at the Department of Respiratory Medicine between January 1990 and December 2015. We calculated for each patient the mean number of hospitalizations for AECOPD/year (H/y). We distinguished 2 groups (G) of patients. G1: <2 H/y and G2: ≥2 H/y. Predictors of multiple admissions identified by univariate analysis were included in the multivariate analysis. Results: The study included 1167 COPD patients (mean age 67 ± 10 years, 97% males). Three hundred six (26%) COPD patients had a mean number of hospitalizations per year ≥ 2. Multivariate logistic regression analysis demonstrated that an mMRC ≥ 2 (Odd ratio [OR] 1.8, 95% confidence interval [CI] 1.08 - 2.99, p = 0.022), a low PaO2 (PaO2 OR 0.97, 95% CI 0.95 - 0.99, p = 0.007) and frequent exacerbations (OR 2.95, 95% CI 2.56 - 3.39, p < 0.001) are independent factors associated with multiple admissions for AECOPD. Conclusions: An mMRC ≥ 2, a low PaO2 and frequent exacerbations are independently associated with multiple hospitalizations for AECOPD. The identification of these high risk COPD patients will be helpful in the decision of intervention strategies.
Designing and Modeling of Efficient Resonant Photo Acoustic Sensors for Spectroscopic Applications  [PDF]
Fahem Yehya, Anil K. Chaudhary
Journal of Modern Physics (JMP) , 2011, DOI: 10.4236/jmp.2011.24028
Abstract: We report the modeling and designing aspects of different types of photo-acoustic (PA) cell based on the excitation of longitudinal, radial and azimuthal mode using CW and pulse lasers. The results are obtained by employing fluid dynamics equations along with Bessel’s function. The obtained results based on stimulation of longitudinal, radial and azimuthally resonance modes of the Photo acoustic signals in the suitable cavity. This is utilized to design highly efficient low volume PA detector for the spectroscopic studies of different types of atmospheric pollutants. We have also studied the dependence of the excited photo acoustic signals on various parameters such as cell radius, laser power, absorption coefficient, quality factor ‘Q’ along with the first longitudinal, radial, azimuthal mode and the pressure. The simulated results show the linearity of the PA signal with different concentration of the gas sample.
Fast Hybrid PSO and Tabu Search Approach for Optimization of a Fuzzy Controller
Nesrine Talbi
International Journal of Computer Science Issues , 2011,
Abstract: In this paper, a fuzzy controller type Takagi_Sugeno zero order is optimized by the method of hybrid Particle Swarm Optimization (PSO) and Tabu Search (TS). The algorithm automatically adjusts the membership functions of fuzzy controller inputs and the conclusions of fuzzy rules. At each iteration of PSO, we calculate the best solution and we seek the best neighbor by Tabu search, this operation minimizes the number of iterations and computation time while maintaining accuracy and minimum response time. We apply this algorithm to optimize a fuzzy controller for a simple inverted pendulum with three rules.
Towards an Intelligent System for Risk Prevention and Management
Fahem Kebair,Frederic Serin
Computer Science , 2009,
Abstract: Making a decision in a changeable and dynamic environment is an arduous task owing to the lack of information, their uncertainties and the unawareness of planners about the future evolution of incidents. The use of a decision support system is an efficient solution of this issue. Such a system can help emergency planners and responders to detect possible emergencies, as well as to suggest and evaluate possible courses of action to deal with the emergency. We are interested in our work to the modeling of a monitoring preventive and emergency management system, wherein we stress the generic aspect. In this paper we propose an agent-based architecture of this system and we describe a first step of our approach which is the modeling of information and their representation using a multiagent system.
Information Modeling for a Dynamic Representation of an Emergency Situation
Fahem Kebair,Frederic Serin
Computer Science , 2009,
Abstract: In this paper we propose an approach to build a decision support system that can help emergency planners and responders to detect and manage emergency situations. The internal mechanism of the system is independent from the treated application. Therefore, we think the system may be used or adapted easily to different case studies. We focus here on a first step in the decision-support process which concerns the modeling of information issued from the perceived environment and their representation dynamically using a multiagent system. This modeling was applied on the RoboCupRescue Simulation System. An implementation and some results are presented here.
Agent-Oriented Approach for Detecting and Managing Risks in Emergency Situations
Fahem Kebair,Frederic Serin
Computer Science , 2009,
Abstract: This paper presents an agent-oriented approach to build a decision support system aimed at helping emergency managers to detect and to manage risks. We stress the flexibility and the adaptivity characteristics that are crucial to build a robust and efficient system, able to resolve complex problems. The system should be independent as much as possible from the subject of study. Thereby, an original approach based on a mechanism of perception, representation, characterisation and assessment is proposed. The work described here is applied on the RoboCupRescue application. Experimentations and results are provided.
Agent-Based Decision Support System to Prevent and Manage Risk Situations
Fahem Kebair,Frederic Serin
Computer Science , 2009,
Abstract: The topic of risk prevention and emergency response has become a key social and political concern. One approach to address this challenge is to develop Decision Support Systems (DSS) that can help emergency planners and responders to detect emergencies, as well as to suggest possible course of actions to deal with the emergency. Our research work comes in this framework and aims to develop a DSS that must be generic as much as possible and independent from the case study.
Interval Type-2 Fuzzy Logic Control of Mobile Robots  [PDF]
Nesrine Baklouti, Robert John, Adel M. Alimi
Journal of Intelligent Learning Systems and Applications (JILSA) , 2012, DOI: 10.4236/jilsa.2012.44031
Abstract: Navigation of autonomous mobile robots in dynamic and unknown environments needs to take into account different kinds of uncertainties. Type-1 fuzzy logic research has been largely used in the control of mobile robots. However, type-1 fuzzy control presents limitations in handling those uncertainties as it uses precise fuzzy sets. Indeed type-1 fuzzy sets cannot deal with linguistic and numerical uncertainties associated with either the mechanical aspect of robots, or with dynamic changing environment or with knowledge used in the phase of conception of a fuzzy system. Recently many researchers have applied type-2 fuzzy logic to improve performance. As control using type-2 fuzzy sets represents a new generation of fuzzy controllers in mobile robotic issue, it is interesting to present the performances that can offer type-2 fuzzy sets by regards to type-1 fuzzy sets. The paper presented deep and new comparisons between the two sides of fuzzy logic and demonstrated the great interest in controlling mobile robot using type-2 fuzzy logic. We deal with the design of new controllers for mobile robots using type-2 fuzzy logic in the navigation process in unknown and dynamic environments. The dynamicity of the environment is depicted by the presence of other dynamic robots. The performances of the proposed controllers are represented by both simulations and experimental results, and discussed over graphical paths and numerical analysis.
Aging Effect on Characteristics of Oil Impregnated Insulation Paper for Power Transformers  [PDF]
Loai S. Nasrat, Nesrine Kassem, Nadia Shukry
Engineering (ENG) , 2013, DOI: 10.4236/eng.2013.51001
Abstract:

This paper deals with experimental investigations of the electrical and physical properties of oil impregnated insulation paper for power transformers at different temperatures. The ac breakdown voltage, tensile strength and water content of insulation papers impregnated in mineral oil for different time periods were investigated. The effect of insulation paper thickness on the electrical and mechanical properties has also been studied. The results showed that the breakdown voltage and the tensile strength decreased with increasing the time of immersion of insulation paper in oil at room temperature, at 5 and at -12. Also, the thermal aging effect on the characteristic of insulation paper has been studied. It was found that high temperatures affect the breakdown voltage and the tensile strength to a great extent.

Approaches for Detailed Modelling of Ultra-Precision Positioning Systems  [PDF]
Dominik Dahlmann, Nesrine Sassi, Berend Denkena
Modern Mechanical Engineering (MME) , 2016, DOI: 10.4236/mme.2016.61005
Abstract: Nowadays, the productivity of ultra-precision machining is fundamentally limited by low feed rates because of the required accuracies in the nanometre range. An increase in motion dynamics leads to disturbances that affect the toolpath’s accuracy. Existing control concepts are not able to reliably detect and compensate the deviations caused by increased dynamics. This paper compares modelling approaches for ultra-precision positioning systems aiming to predict and compensate occurring deviations.
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