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Search Results: 1 - 10 of 155 matches for " Rafig Azzam "
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Shear Failure Criterion and Constant Volume Ring Shear Testing Method for Clayey Soil  [PDF]
Rafig Azzam
Engineering (ENG) , 2016, DOI: 10.4236/eng.2016.88051
Abstract: This paper discusses the shortcomings of the traditional Coulomb shear criterion and the direct shear-box testing method used for clayey soil and presents a modified shear criterion that considers the elasto-plastic behavior of cohesive soil. This modified approach involves direct shear testing under constant volume, a method that has been developed by the author. A modified ring shear apparatus and the theory behind the shear criterion and its implication for slope stability analysis are then discussed and the results of investigated tuffitic clayey sediments are presented. The results show that the presented new shear criterion does not consider the cohesion as material constant, but rather it depends on the void ratio. In this case, the stress state and the consolidation status and thus the elasto-plastic behavior of the clayey soil are considered.
Tuberculosis among COPD Patients in Guba City, Azerbaijan  [PDF]
Amir V. Aliyev, Rafig A. Chobanov
Journal of Tuberculosis Research (JTR) , 2015, DOI: 10.4236/jtr.2015.34022
Abstract: Chronic obstructive pulmonary disease (COPD) retains their relevance. It is necessary to take into account that growth in the number of patients with lung diseases. In addition, there is a growth in the number of tuberculosis patients. According to the criteria of the Ministry of Health, patients with COPD are at risk.
Performance of Family and Non-family Firms with Self-Selection: Evidence from Dubai  [PDF]
Belaid Rettab, Azzeddine Azzam
Modern Economy (ME) , 2011, DOI: 10.4236/me.2011.24070
Abstract: This paper contributes to the literature on comparative performance of family and non-family businesses by accounting for self-selection and by comparing performance within and across sectors. Using an extensive data set of Dubai businesses in the four different major sectors in the Dubai economy (construction, manufacturing, services, and trading); we find that the sector matters. Family businesses outperform nonfamily businesses in trading, followed by construction as a far second. Performance of family businesses is weakest in manufacturing and services, only in trading did family businesses outperform nonfamily exporting businesses in other sectors. Reasons for that are discussed and policy implications are drawn. We also find strong evidence of self-selection bias.
Dependence of the GRB Lag-Luminosity Relation on Redshift in the Source Frame  [PDF]
Walid J. Azzam
International Journal of Astronomy and Astrophysics (IJAA) , 2012, DOI: 10.4236/ijaa.2012.21001
Abstract: The lag-luminosity relation for gamma-ray bursts (GRBs) is an anti-correlation between the time lag, ?lag, which represents the delay between the arrival of hard and soft photons, and the isotropic peak luminosity, L. In this paper, we use a sample of 43 Swift bursts, which was taken from Ukwatta et al., to investigate whether this relation depends on redshift. Both the z-correction and the k-correction are taken into account. Our analysis consists of binning the data in redshift, z, then applying a fit of the form: for each bin, where ?lag0 is the time-lag in the burst’s source frame, and is the corresponding mean value for the entire sample. The goal is to see whether the two fitting parameters, A and B, evolve in a systematic way with z. Our results indicate that both the normalization, A, and the slope, B, seem to vary in a systematic way with redshift. We note that although good best-fits were obtained, with reasonable values for both the linear regression coefficient, r, and the reduced chi-squared, the data showed large scatter. Also, the number of GRBs in the sample studied is not large, and thus our conclusions are only tentative at this point. A flat universe with M = 0.27, ?? = 0.73, and a Hubble constant, H0 = 70 km.s-1.Mpc-1 is assumed.
Quantum Inspired Shape Representation for Content Based Image Retrieval  [PDF]
Rahmeh Jobay, Azzam Sleit
Journal of Signal and Information Processing (JSIP) , 2014, DOI: 10.4236/jsip.2014.52008

Content Based Image Retrieval (CBIR) is a technique in which images are indexed based on their visual contents and retrieving is only based upon these indexed images contents. Among the visual contents to describe the image details is shape. Shape of object, is considered as the most important distinguishable feature which living things can easily recognize, which is also a fact while this line is being written, and large efforts are currently underway in describing image contents by their shapes. Inspired by the core foundation of quantum mechanics, a new easy shape representation for content based image retrieval is proposed by borrowing the concept of quantum superposition into the basis of distance histogram. Results show better retrieval accuracy of the proposed method when compared with distance histogram.

A Brief Review of the Amati Relation for GRBs  [PDF]
Walid J. Azzam
International Journal of Astronomy and Astrophysics (IJAA) , 2016, DOI: 10.4236/ijaa.2016.64030
Abstract: Gamma-ray bursts (GRBs) are the most powerful explosions in the universe. Alt-hough the exact mechanism behind these explosions remains elusive, GRBs hold great promise as cosmological probes for two main reasons: they have been observed up to very high redshift (z > 9), and their gamma-ray emission is unencumbered by any intervening dust. Several GRB energy and luminosity indicators have been discovered. These indicators correlate an observable quantity, like the intrinsic peak energy, Ep,i, in the?\"\"spectrum of a burst to an unobservable parameter like the equivalent isotropic energy, Eiso, or the isotropic peak luminosity, Lp,iso. This paper provides a brief review of one of these energy and luminosity indicators, the Amati relation, and discusses its potential use as a cosmological probe.
Peak Energy Correlations for Gamma-Ray Bursts  [PDF]
Walid J. Azzam
Journal of Applied Mathematics and Physics (JAMP) , 2017, DOI: 10.4236/jamp.2017.58124
Abstract: Gamma-ray bursts (GRBs) are the most powerful explosions in the universe. Over the past two decades, several GRB energy and luminosity correlations were discovered. These correlations typically involve an observable parameter, like the observed peak energy, Ep,obs, and a non-observable quantity, like the equivalent isotropic energy, Eiso. This paper provides a brief review of GRB peak energy correlations. Specifically, it focuses on the Amati relation, which correlates Ep,obs and Eiso, and the Ghirlanda relation, which correlates Ep,obs and Ey, the total energy corrected for beaming. The paper also discusses the physical interpretation of these relations in the context of the internal shock model.
Efficacy of Sensory Integration Therapy in Improving Gross Motor Coordination and Grip Control in Down Syndrome Children  [PDF]
Ahmed M. Azzam
World Journal of Neuroscience (WJNS) , 2019, DOI: 10.4236/wjns.2019.92002
Abstract: This work was carried out to investigate the efficacy of sensory integration therapy in improving gross motor coordination and grip control in Down syndrome children. Thirty children were enrolled in this study and randomly assigned into two groups: group A received (sensory integration therapy program plus specific physiotherapy training) and group B received (specific physiotherapy training program only). Motor coordination test measures (Balancing backward, Hopping, Jumping from side to side and Transferring boxes) to test and follow gross motor coordination, handheld dynamometer to test and follow grip control ability and kinesthesia test to test and follow awareness of joint position and movement. These measurements were taken before initial treatment and after 12 weeks of treatment. The children parents in both groups A and B were instructed to complete 3 hours of the home routine program. Data analysis was available on the 30 Down syndrome children participating in the study. The difference between pre- and post-treatment results was more significant in Motor
The Matrix of Maximum Out Forests of a Digraph and Its Applications
Rafig Agaev,Pavel Chebotarev
Mathematics , 2006,
Abstract: We study the maximum out forests of a (weighted) digraph and the matrix of maximum out forests. A maximum out forest of a digraph G is a spanning subgraph of G that consists of disjoint diverging trees and has the maximum possible number of arcs. If a digraph contains any out arborescences, then maximum out forests coincide with them. We provide a new proof to the Markov chain tree theorem saying that the matrix of Ces`aro limiting probabilities of an arbitrary stationary finite Markov chain coincides with the normalized matrix of maximum out forests of the weighted digraph that corresponds to the Markov chain. We discuss the applications of the matrix of maximum out forests and its transposition, the matrix of limiting accessibilities of a digraph, to the problems of preference aggregation, measuring the vertex proximity, and uncovering the structure of a digraph.
Spanning Forests of a Digraph and Their Applications
Rafig Agaev,Pavel Chebotarev
Mathematics , 2006, DOI: 10.1023/A:1002862312617
Abstract: We study spanning diverging forests of a digraph and related matrices. It is shown that the normalized matrix of out forests of a digraph coincides with the transition matrix in a specific observation model for Markov chains related to the digraph. Expression are given for the Moore-Penrose generalized inverse and the group inverse of the Kirchhoff (Laplacian) matrix. These expressions involve the matrix of maximum out forest of the digraph. Every matrix of out forests with a fixed number of arcs and the normalized matrix of out forests are represented as polynomials in the Kirchhoff matrix; with the help of these identities new proofs are given for the matrix-forest theorem and some other statements. A connection is specified between the forest dimension of a digraph and the degree of an annihilating polynomial for the Kirchhoff (Laplacian) matrix. Some accessibility measures for digraph vertices are considered. These are based on the enumeration of spanning forests.
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