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Search Results: 1 - 10 of 8818 matches for " Michel Naser "
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A Reliable and Efficient Time Synchronization Protocol for Heterogeneous Wireless Sensor Network  [PDF]
Masoume Jabbarifar, Alireza Shameli Sendi, Alireza Sadighian, Naser Ezzati Jivan, Michel Dagenais
Wireless Sensor Network (WSN) , 2010, DOI: 10.4236/wsn.2010.212109
Abstract: L-SYNC is a synchronization protocol for Wireless Sensor Networks which is based on larger degree clustering providing efficiency in homogeneous topologies. In L-SYNC, the effectiveness of the routing algorithm for the synchronization precision of two remote nodes was considered. Clustering in L-SYNC is according to larger degree techniques. These techniques reduce cluster overlapping, resulting in the routing algorithm requiring fewer hops to move from one cluster to another remote cluster. Even though L-SYNC offers higher precision compared to other algorithms, it does not support heterogeneous topologies and its synchronization algorithm can be influenced by unreliable data. In this paper, we present the L-SYNCng (L-SYNC next generation) protocol, working in heterogeneous topologies. Our proposed protocol is scalable in unreliable and noisy environments. Simulation results illustrate that L-SYNCng has better precision in synchronization and scalability.
A Stateful Approach to Generate Synthetic Events from Kernel Traces
Naser Ezzati-Jivan,Michel R. Dagenais
Advances in Software Engineering , 2012, DOI: 10.1155/2012/140368
Abstract: We propose a generic synthetic event generator from kernel trace events. The proposed method makes use of patterns of system states and environment-independent semantic events rather than platform-specific raw events. This method can be applied to different kernel and user level trace formats. We use a state model to store intermediate states and events. This stateful method supports partial trace abstraction and enables users to seek and navigate through the trace events and to abstract out the desired part. Since it uses the current and previous values of the system states and has more knowledge of the underlying system execution, it can generate a wide range of synthetic events. One of the obvious applications of this method is the identification of system faults and problems that will appear later in this paper. We will discuss the architecture of the method, its implementation, and the performance results. 1. Introduction Tracing complete systems provides information on several system levels. The use of execution traces as a method to analyze system behavior is increasing among system administrators and analysts. By examining the trace events, experts can detect the system problems and misbehaviors caused by program errors, application misconfigurations, and also attackers. Linux trace toolkit next generation (LTTng), a low-impact and precise Linux tracing tool, provides a detailed execution trace of system calls, operating system operations, and user space applications [1]. The resulting trace files can be used to analyze the traced system at kernel and user space levels. However, these trace files can grow to a large number of events very quickly and make analysis difficult. Moreover, this data contains too many low-level system calls that often complicate the reading and comprehension. Thus, the need arises to somehow reduce the size of huge trace files. In addition, it is better to have relatively abstract and high-level events that are more readable than raw events and at the same time reflect the similar system behavior. Trace abstraction technique reduces the size of original trace by grouping the events and generating high-level compound synthetic events. Since synthetic events reveal more high-level information of the underling system execution, they can be used to easily analyze and discuss the system at higher levels. To generate such synthetic events, it is required to develop efficient tools and methods to read trace events, detect similar sections and behaviors, and convert them to meaningful coarse-grained events. Most of the trace
Effects of pregnancy and childbirth on the pelvic floor
Michel Naser,Valentín Manríquez,Mauricio Gómez
Medwave , 2012,
Abstract: The pelvic floor dysfunctions include urinary incontinence, pelvic organ prolapsed and anal incontinence. One in ten women will be subjected to surgery for pelvic floor dysfunction during their lifetime. In addition, between 30% and 50% will have a recurrence of these interventions. Motherhood is a factor that contributes significantly to the submission of pelvic dysfunctions. There is still no proven evidence that vaginal delivery is an absolutely crucial factor for the presence of pelvic floor dysfunction. There is extensive research on pregnancy and child birth and their effects on the pelvic floor and if some of the obstetric action scan be modified in order to protect it from potential damage.
Automorphism of Cyclic Codes  [PDF]
Naser Amiri
Intelligent Information Management (IIM) , 2012, DOI: 10.4236/iim.2012.425043
Abstract: We investigate how the code automorphism group can be used to study such combinatorial object as codes. Consider GF(qn) as a vector over GF(q). For any k = 0, 1, 2, 3, ???, n. Which GF(qn) exactly one subspace C of dimension k and which is invariant under the automorphism.
New Modeling for Generation of Normal and Abnormal Heart Rate Variability Signals  [PDF]
Naser Safdarian
Journal of Biomedical Science and Engineering (JBiSE) , 2014, DOI: 10.4236/jbise.2014.714110
Abstract: This research is performed based on the modeling of biological signals. We can produce Heart Rate (HR) and Heart Rate Variability (HRV) signals synthetically using the mathematical relationships which are used as input for the Integral Pulse Frequency Modulation (IPFM) model. Previous researches were proposed same methods such as one model of ECG signal synthetically based on RBF neural network, a model based on IPFM with random threshold, method was based on the estimation of produced signals which are dependent on autonomic nervous system using IPFM model with fixed threshold, a new method based on the theory of vector space that based on time-varying uses of IPMF model (TVTIPMF) and special functions, and two different methods for producing HRV signals with controlled characteristics and structure of time-frequency (TF) for using non-stationary HRV analysis. In this paper, several chaotic maps such as Logistic Map, Henon Map, Lorenz and Tent Map have been used. Also, effects of sympathetic and parasympathetic nervous system and an internal input to the SA node and their effects in HRV signals were evaluated. In the proposed method, output amount of integrator in IPFM model was compared with chaotic threshold level. Then, final output of IPFM model was characterized as the HR and HRV signal. So, from HR and HRV signals obtaining from this model, linear features such as Mean, Median, Variance, Standard Deviation, Maximum Range, Minimum Range, Mode, Amplitude Range and frequency spectrum, and non-linear features such as Lyapunov Exponent, Shanon Entropy, log Entropy, Threshold Entropy, sure Entropy and mode Entropy were extracted from artificial HRV and compared them with characteristics as extracted from natural HRV signal. Also, in this paper two patients that called high sympathetic Balance and Cardiovascular Autonomy Neuropathy (CAN) which is detected and evaluated by HRV signals were simulated. These signals by changing the values of the some coefficients of the normal simulated signal and with extracted frequency feature from these signals were simulated. For final generation of these abnormal signals, frequency features such as energy of low frequency band (EL), energy of high frequency band (HL), ratio of energy in low frequency band to the energy in high frequency band (EL/EH), ratio of energy in low frequency band to the energy in all frequency band (EL/ET) and ratio of energy in high frequency band to the energy in all frequency band (EH/ET) from abnormal signals were extracted and compared with these extracted values from normal signals. The
A New Solution for the Friedmann Equations  [PDF]
Naser Mostaghel
International Journal of Astronomy and Astrophysics (IJAA) , 2016, DOI: 10.4236/ijaa.2016.61010
Abstract: Assuming a flat universe expanding under a constant pressure and combining the first and the second Friedmann equations, a new equation, describing the evolution of the scale factor, is derived. The equation is a general kinematic equation. It includes all the ingredients composing the universe. An exact closed form solution for this equation is presented. The solution shows remarkable agreement with available observational data for redshifts from a low of z = 0.0152 to as high as z = 8.68. As such, this solution provides an alternative way of describing the expansion of space without involving the controversial dark energy.
Evaluate the Accuracy of Fargas and BLM Models for Identification of Erosion Intensity  [PDF]
Naser Abdi
Open Journal of Geology (OJG) , 2016, DOI: 10.4236/ojg.2016.611103
Abstract: Erosion process not only changes the land use to badlands, but also produces sediments that are dumped in the dam reservoirs, reduces the reservoir volume and finally makes it useless. So, it is necessary to do study on erosion intensity and the sediment production evaluation for which there are some methods and models. The experimental Fargas and BLM models are largely used for this issue, in Iran as well as many other countries, separately or together based on the data availability. These studies results are as data for sediment supply estimation in different watershed management studies. So, the result accuracy is important for determination of sediment occurrence. This study evaluates these models’ results accuracy, in order to find the limitations and any solutions. Therefore, these two models were used and run in the same area, Aghbolagh drainage basin, Iran; the results were compared and evaluated. These models are based on some factors like rock type, drainage density, surface erosion and litter cover. The study includes field and laboratory analysis. The data were combined in GIS software and processed. The results reveal that, Fargas model predicts 3.67%, 14.26% and 81.06% of the area susceptible for high, severe and very severe erosion respectively; whilst, referring to BLM model outcome, 42.96% area has high sensitivity; 42.96% and 24.94% of the area have high and severe sensitivity for erosion, respectively. Furthermore, both models show same severity for around 18% of the study area. So, for these two models results very low similarities are concluded, which could be an indication of low reliability of the results, especially when they are used separately without any combination or comparison. Finally, it is recommended to use both of them together, or use another method beside each mentioned models.
Effects of Time Dilation on the Measurements of the Hubble Constant  [PDF]
Naser Mostaghel
International Journal of Astronomy and Astrophysics (IJAA) , 2018, DOI: 10.4236/ijaa.2018.84024
Abstract: We show that, when measuring the Hubble constant by starting the evaluation from the time of the big bang era, the effect of time dilation results in a decrease in the value of the Hubble constant. But when evaluating the Hubble constant by starting the evaluation from the present time, the effect of time dilation results in an increase in the value of the Hubble constant. To elucidate the process, the time dilation is calculated both directly and through Schwarzschild solution of the Einstein equation for the gravitational time dilation. It is concluded that both measured values are valid but because of time dilation, different starting times for the evaluation of the Hubble constant have resulted in different measured values for the Hubble constant.
Jorge Lecannelier A,César Sandoval S,Michel Naser N,Valentín Manríquez G
Revista Chilena de Obstetricia y Ginecología , 2008,
Abstract: Objetivos: Describir una técnica quirúrgica, novedosa en el medio nacional, de abordaje vaginal, para el tratamiento del prolapso apical: la suspensión transvaginal alta a ligamentos úterosacros (STALUS). Método: Estudio descriptivo longitudinal, de 57 pacientes con defectos apicales, a los cuales se les realizó esa técnica entre Diciembre de 2002 y Octubre 2005. Se realizó estadística descriptiva y test t (2 muestras) para análisis de pronóstico anatómico (POP-Q). Para análisis de potenciales factores pronósticos se utilizó ANOVA, regresión lineal y logística. Resultados: El tiempo operatorio promedio fue de 151 minutos. El resultado anatómico (POP-Q), pre y postoperatorio, resultó favorable y estadísticamente significativo, en los nueve puntos evaluados, 49 de las 54 pacientes fueron seguidas en promedio durante 15 meses. En el compartimiento apical (punto C) obtuvimos curación del 89% y no hubo fracasos. En la pared anterior, 22% de las pacientes recidivaron. En cuanto a las complicaciones, se produjo una fístula ureterovaginal. Conclusiones: Tomando las precauciones necesarias, es una técnica segura y reproducible, con buenas tasa de curación. Asegurar la indemnidad del uréter, siempre será una obligación. La recidiva en pared anterior, aunque sea asintomática, resulta ser extremadamente alta, lo que nos obliga a pensar en nuevas técnicas de abordaje de este compartimiento. Objective: To describe a novel surgery technique in the national ground, of vaginal approach for the treat-ment of apical prolapse: the transvaginal high suspensión to the uterosacral ligaments (STALUS). Method: It is a longitudinal descriptive study that included 57 patients with apical support defects, in which this technique was performed between December 2002 and October 2005. Descriptive statistics and t test were per-formed for the anatomical outcome (POP-Q). For the potential prognosis factors, ANOVA, lineal regression and logistic, were used. Results: The average surgery time was 151 minutes. The anatomical result (POP-Q), before and after surgery, was favourable and significant in the nine points evaluated. 49 of 54 patients were followed for 15 months in average. In the apical compartment (C point) we got an 89% of cure and there were no failure. In the anterior wall, instead, 22% of our patients recurred. About complications, there was an ureterovaginal fistula. Conclusions: If all precautions are taking, there is a secure and reproducible technique, with good cure rate. To secure the uréter it is always an obligation. The recurrence in the anterior wall, even been asy
Valentín Manríquez G,César Sandoval S,Jorge Lecannelier A,Michel Naser N
Revista Chilena de Obstetricia y Ginecología , 2010,
Abstract: A través de la historia la neuromodulación ha demostrado ser una alternativa de tratamiento eficaz en el manejo de diversas disfunciones del piso pélvico. Distintas técnicas intentan conseguir un objetivo común, sin embargo, el éxito terapéutico es disímil dependiendo de la severidad y tipo de patología. Describimos los aspectos clínicos y operacionales relacionados con las diversas técnicas, así como los mecanismos de acción propuestos para la neuromodulación. Through hystory, neuromodulation have proved to be an effective alternative of management of pelvic floor dysfunctions. Several technical alternatives try to reach a same therapeutic objetive, however, depending on the severity and type of symptom their succes differ. We describe the clinical and technical aspects related to those different technics so as the mechanisms of action that are propose for the neuromodulation.
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