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Search Results: 1 - 10 of 23 matches for " Khalfallah Ikbel "
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Solitary Endobronchial Papilloma Mimicking a Neoplastic Lesion  [PDF]
Smadhi Hanen, Khalfallah Ikbel, Diouani Mohamed Fethi, Abdennadher Mahdi, Attia Monia, Ayadi-Kaddour Aida, Megdiche Mohamed Lamine
Open Journal of Respiratory Diseases (OJRD) , 2018, DOI: 10.4236/ojrd.2018.83005
Abstract: Papilloma is a rare benign tumor. Laryngeal location is the most frequent. The bronchial involvement remains unusual. It represents 0.38% of pulmonary tumors. We report the case of a 39-year-old, smoker man, who consulted for a cough following during six months with persistent radiological opacity despite antibiotic treatment. The physical examination was without particularities. Flexible bronchoscopy revealed a swollen endobronchial lesion completely obstructing the orifice of the intermediate trunk. Bronchial biopsies at this level showed inflammatory mucosa. The chest CT scan objectified an endobronchial tissular mass in the intermediate trunk. Pulmonary neoplasia was suspected. Diagnostic and therapeutic surgery was performed. Histopathological examination concluded to an endobronchial squamous papilloma.
2D FE Description of Reinforced Concrete Beams Behaviour
Khalfallah Salah
Journal of Engineering and Applied Sciences , 2012,
Abstract: The first series of beams with no shear reinforcement tested by Bresler and Scordelis to investigate the behaviour of reinforced concrete beams in shear is used to calibrate the proposed finite element approach. A non-linear finite element analysis has been established to predict the shear strength of reinforced concrete beams. Based on the smeared crack modelling of quasi-brittle materials, various refinements such as: the shear retention factor, the tension stiffening concept and the dowel action, are introduced. This approach is based on the combination of the behaviour of biaxial description of membranous concrete elements and truss uniaxial reinforcing bars with a full bond between concrete and steel. Beyond the strength of concrete in tension, the tensile capacity of concrete maintained by the reinforcing bars (tension stiffening effect) is assumed. The mathematical relationships of stress-strain materials are displayed in the following section. The procedure is based on incremental finite element analysis and established with 2D description of behaviour using Kupfer failure criteria. The finite element simulation is validated by comparison of numerical results with available experimental data, regarded as a benchmark for various numerical models. Correlation studies between obtained results and experimental values are conducted to assess the validity of the proposed approach.
Exact traveling wave solutions of the (2+1) Dimensional Boussinesq Equation
Mohammed Khalfallah
Sel?uk Journal of Applied Mathematics , 2008,
Abstract: The repeated homogeneous balance method is used to construct exact trav eling wave solutions of the (2+1) dimensional Boussinesq equation, in which the homogeneous balance method is applied to solve the Riccati equation and the reduced nonlinear ordinary differential equation, respectively. Many new exact traveling wave solutions are successfully obtained. This method is straight forward and concise, and it can be also applied to other nonlinear evolution equations.
Anisotropic Effect on Elastic Interaction Between Dislocation and General Grain Boundaries in Some Hexagonal Metals: Be,Y, Zn
M. Toubane,O. Khalfallah
Journal of Engineering and Applied Sciences , 2012,
Abstract: In this study, we examine the anisotropic effect on elastic interaction between dislocations and general grain boundaries for hexagonal metals; Be Y and Zn. In the setting of the anisotropic linear elasticity in continuous media the calculations of the elastic interaction energy E have been gotten by Head then to be improved by Barnett and Lothe. The dislocations in elastic interaction with a grain boundary in a bicrystal of an elastically anisotropic material are submitted to an image force Fi = - E/d. The results are represented in isoenergy cards on a stereographic projection. The result showed that the interaction energy is inversely depends to the factor of anisotropy H. The maximal energy of interaction is lower then 14 pJ m 1 its always weaker compared to the case of the cubic metals where it is of the order of 100 pJ m 1. The image force can be attractive repulsive or null. The proportion of attracted dislocations depends to the disorientation and the factor of anisotropy H.
Analysis of the Morpho-physiological Variation within Some Algerian Populations of Sulla (Hedysarum coronarium L., Fabaceae)
Rachida Issolah,Nadra Khalfallah
Journal of Biological Sciences , 2007,
Abstract: As a part of the characterization and the valorization of plant genetic resources of fodder and pastoral interest in Algeria, fourteen natural populations of Hedysarum coronarium L. were subjected to a morpho-physiological study. Ecological factors (altitude and rainfall) of the originating environment of the different populations were considered. Thirty four characteristics related to seed weight, seedling emergence, vegetative development, flowering and formation of fruiting heads were included in the study. The results indicate the existence of variability within the species and between the populations, especially for the rate of seedlings at the second simple leaf stage, the development of the height axis, the end of the bloom and the full fruiting heads characteristics which are significant. This would be linked to the ecological factors of the environment of origin, especially the altitude which would constitute the most important factor. The results of principal components analysis show off some important characteristics, particularly the numbers of leaves and ramifications per plant, which oppose themselves to certain characteristics linked to the breeding (flowering and formation of fruiting heads). H. coronarium L. should be developed, particularly in the isolated and disinherited areas, where they could adapt themselves with advantage.
Complex spaces and nonstandard schemes
Adel Khalfallah,Siegmund Kosarew
Journal of Logic and Analysis , 2010, DOI: 10.4115/jla.v2i0.77
Abstract:
Complex Spaces and Nonstandard Schemes
Adel Khalfallah,Siegmund Kosarew
Mathematics , 2008,
Abstract: We apply methods of nonstandard mathematics in order to regard analytic geometry in a very different way. For example, complex spaces are seen to be the "standard part" of certain algebraic nonstandard schemes. We construct a category of such schemes, sitting in between usual algebraic schemes (over the complex numbers) and that of complex spaces. We clarify the structure of prime ideals in a Stein algebra, coming from nonstandard points and show in particular that ANY maximal and minimal prime ideal in a Stein algebra is the vanishing ideal of a nonstandard point. Other applications of our point of view are given for differential forms (a la Leibniz), generic points (as nonstandard ones), meromorphic functions, hyperbolicity. The essential tools taken from nonstandard mathematics and adapted for our purposes, are summarized in the appendix.
Synthesis and Characterization of CuIn2n+1 S3n+2 (with n = 0, 1, 2, 3 and 5) Powders  [PDF]
Naoufel Khemiri, Dhafer Abdelkader, Bilel Khalfallah, Mounir Kanzari
Open Journal of Synthesis Theory and Applications (OJSTA) , 2013, DOI: 10.4236/ojsta.2013.21003
Abstract:

CuIn2n+1 S3n+2 crystals were synthesized by horizontal Bridgman method using high purity copper, indium, sulfur elements. The phases and crystallographic structure of the CuIn2n+1S3n+2 crystals were analyzed by X-ray diffraction (XRD) and the composition of the material powders was determined using the energy dispersive X-ray analysis (EDX). Measurement data revealed that CuIn2n+1S3n+2 materials have not the same structure. In fact, CuInS2 and CuIn3S5 crystallize in the chalcopyrite structure whereas CuIn5S8, CuIn7S11 and CuIn11S17 crystallize in the cubic spinel structure.

 

New Three-Level Resource Management Enhancing Quality of Offline Hardware Task Placement on FPGA
Ikbel Belaid,Fabrice Muller,Maher Benjemaa
International Journal of Reconfigurable Computing , 2010, DOI: 10.1155/2010/980762
Abstract: Currently, reconfigurable hardware devices feature a high density of heterogeneous resources to enable multitasking and offer flexibility in application needs. These concepts raise the need for efficient management of hardware tasks and hardware resources. The scheduling of hardware tasks is highly dependent on placement. Placement focuses on allocation of hardware resources required by the scheduled hardware tasks. In this paper, we propose novel three-level resource management that investigates enhancement of placement quality by reducing task rejection, configuration overheads, and by optimizing resource utilization. Improving placement quality will produce significant enhancement of performance for scheduling and overall execution time of the application in FPGA. Hence, the placement problem is formulated into a constrained optimization problem and resolved with powerful solvers using the Branch and Bound method. The obtained results of an application of heterogeneous hardware tasks show an average resource utilization of 36% of the available resources on the reconfigurable region and an overall overhead of 11% of total application running time, and we have eliminated the issue of task rejection. Compared to static implementation, the gain in resource utilization within the reconfigurable region achieves up to 43%. 1. Introduction Scheduling and placement are strongly linked. The scheduler decides which of the ready tasks should be executed next and calls the placer to find a feasible location. The scheduler decision should be taken in accordance with the ability of placer to allocate free resources required by the elected task. Field-Programmable Gate Array (FPGA) is the most widely used reconfigurable hardware device. Today’s FPGA devices provide several million reconfigurable heterogeneous resources. The development of dynamic partial reconfiguration in the FPGAs allows reconfiguring only the necessary part of the FPGA when required without interfering with any other parts running on the same FPGA. While this technique can increase device utilization and performance of scheduling and application, it also leads to high configuration overhead, fragmentation, and complex allocation situations of hardware tasks [1]. Frequently, the existing methods of placement face these issues. Consequently, the quality of placement and performance of the scheduling degrades while the overall response time increases. So, there exists a serious need to define an efficient method that helps manage the area of resources. In general, the placement of hardware tasks
Static Scheduling of Periodic Hardware Tasks with Precedence and Deadline Constraints on Reconfigurable Hardware Devices
Ikbel Belaid,Fabrice Muller,Maher Benjemaa
International Journal of Reconfigurable Computing , 2011, DOI: 10.1155/2011/591983
Abstract: Task graph scheduling for reconfigurable hardware devices can be defined as finding a schedule for a set of periodic tasks with precedence, dependence, and deadline constraints as well as their optimal allocations on the available heterogeneous hardware resources. This paper proposes a new methodology comprising three main stages. Using these three main stages, dynamic partial reconfiguration and mixed integer programming, pipelined scheduling and efficient placement are achieved and enable parallel computing of the task graph on the reconfigurable devices by optimizing placement/scheduling quality. Experiments on an application of heterogeneous hardware tasks demonstrate an improvement of resource utilization of 12.45% of the available reconfigurable resources corresponding to a resource gain of 17.3% compared to a static design. The configuration overhead is reduced to 2% of the total running time. Due to pipelined scheduling, the task graph spanning is minimized by 4% compared to sequential execution of the graph. 1. Introduction An important trend in real-time applications implemented in reconfigurable computing systems consists in using reconfigurable hardware devices to increase performances and to guarantee temporal constraints. These reconfigurable devices provide a high density of heterogeneous resources in order to satisfy application requirements and especially to enable parallel computing. Furthermore, the devices employ the pertinent concept of run-time partial reconfiguration which allows reconfiguration of a portion of available resources without interrupting the remainder parts running in the same device. Consequently, the concept increases resource utilization and application performance. Periodic partially ordered activities represent the major computational demand in real-time systems such as real-time control and digital signal processing. This category of repetitive computation is described by directed acyclic graphs (DAGs). Implementation of these DAGs in reconfigurable hardware devices consists in scheduling tasks to a limited number of nonidentical units shaped on the area of reconfigurable resources, while respecting the four constraints described as follows. (1) The periodicity constraint: each task is repeated periodically according to its ready times in the graph. Thus, if task has a period , then for all , , where and are the th and the th repetitions of task , and and are their start times. (2) The precedence constraint: to maintain the rightness of task precedences, in each iteration, a task can be executed only if all its
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