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Search Results: 1 - 10 of 145508 matches for " B Mahdi "
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Impact of Some Antibiotics on Bacteria Isolated from Appendices in Kirkuk Province, Iraq  [PDF]
Ayoub A. Bazzaz, Diyari A. K. Lor, Najdat B. Mahdi
Advances in Bioscience and Biotechnology (ABB) , 2018, DOI: 10.4236/abb.2018.91001
Abstract: A bacteriological study of 50 appendectomy cases for patients diagnosed by physicians to be appendicitis, within Kirkuk province was carried out to isolate the habitat bacteria of appendix and to assess the impact of some antibiotics on isolated bacterial species from the appendices. The age of patients ranged between 3 - 45 year old (21 male and 29 female). The culture results showed 94% single isolate with 2% negative growth and 4% mixed growth were obtained. The gram positive bacteria isolate formed (11.77%) less than gram negative (88.23%). The total isolates represented 51 included Escherichia coli 34 (66.66%), followed by Enterococcus faecalis 3 (5.89%), Klebsiella pneumonia 3 (5.89%), Citrobacter youngae 2 (3.92%), Raultella terrigena 2 (3.92%), Pseudomonas aeruginosa
Robustness of Multi Biometric Authentication Systems against Spoofing
Mahdi Hariri,Shahriar B. Shokouhi
Computer and Information Science , 2011, DOI: 10.5539/cis.v5n1p77
Abstract: Nowadays biometric authentication systems have been more developed, especially in secure and financial systems; so cracking a biometric authentication system is now a growing concern. But their security has not received enough attention. Imitating a biometric trait of a genuine user to deceive a system, spoofing, is the most important attacking method. Multi biometric systems have been developed to overcome some weaknesses of single biometric systems because the forger needs to imitate more than one trait. No research has further investigated the vulnerability of multimodal systems against spoof attack. We empirically examine the robustness of five fixed rules combining similarity scores of face and fingerprint traits in a bimodal system. By producing different spoof scores, the robustness of fixed combination rules is examined against various possibilities of spoofing. Robustness of a multi biometric system depends on the combination rule, the spoof trait and the intensity of spoofing. Min rule shows the most robustness when face is spoofed especially in very secure systems but when the fingerprint is faked the max rule shows the least vulnerability against possibilities of spoofing.
Towards Economic Single-Phase Motor  [PDF]
Mahdi Alshamasin
Energy and Power Engineering (EPE) , 2013, DOI: 10.4236/epe.2013.59058
Abstract:

Studying of operation balance in single-phase induction motors is an issue of interest due to the need for reducing the power consumption and increasing the motors’ life. The paper focuses on improving the motor performance by balancing the stator phase operation for the most common-used connection diagrams of single-phase capacitor-run induction motors (SPCRIMs) and three-phase induction motors (TPIMs) operating from single-phase supply (SPS). Therefore, a mathematical model is used to balance the motor operation by varying the frequency supply voltage. Characteristics of balancing parameters are investigated, various methods of motor balancing are presented and comparisons were done among these balancing methods.

Unscreened Coulomb interactions and quantum spin Hall phase in neutral zigzag graphene ribbons
Mahdi Zarea,Carlos Büsser,Nancy Sandler
Physics , 2008, DOI: 10.1103/PhysRevLett.101.196804
Abstract: A study of the effect of unscreened Coulomb interactions on the quantum spin Hall (QSH) phase of finite-width neutral zigzag graphene ribbons is presented. By solving a tight-binding Hamiltonian that includes the intrinsic spin-orbit interaction (I-SO), exact expressions for band-structures and edge-states wavefunctions are obtained. These analytic results, supported by tight-binding calculations, show that chiral spin-filtered edge states are composed of localized and damped oscillatory wavefunctions, reminiscent of the ones obtained in armchair ribbons. The addition of long-range Coulomb interactions opens a gap in the charge sector with a gapless spin sector. In contrast to armchair terminations, the charge-gap vanishes exponentially with the ribbon width and its amplitude and decay-length are strongly dependent on the I-SO coupling. Comparison with reported ab-initio calculations are presented.
Linear Index Coding via Graph Homomorphism
Javad B. Ebrahimi,Mahdi Jafari Siavoshani
Computer Science , 2014,
Abstract: It is known that the minimum broadcast rate of a linear index code over $\mathbb{F}_q$ is equal to the $minrank_q$ of the underlying digraph. In [3] it is proved that for $\mathbb{F}_2$ and any positive integer $k$, $minrank_q(G)\leq k$ iff there exists a homomorphism from the complement of the graph $G$ to the complement of a particular undirected graph family called "graph family $\{G_k\}$". As observed in [2], by combining these two results one can relate the linear index coding problem of undirected graphs to the graph homomorphism problem. In [4], a direct connection between linear index coding problem and graph homomorphism problem is introduced. In contrast to the former approach, the direct connection holds for digraphs as well and applies to any field size. More precisely, in [4], a graph family $\{H_k^q\}$ is introduced and shown that whether or not the scalar linear index of a digraph $G$ is less than or equal to $k$ is equivalent to the existence of a graph homomorphism from the complement of $G$ to the complement of $H_k^q$. Here, we first study the structure of the digraphs $H_k^q$. Analogous to the result of [2] about undirected graphs, we prove that $H_k^q$'s are vertex transitive digraphs. Using this, and by applying a lemma of Hell and Nesetril [5], we derive a class of necessary conditions for digraphs $G$ to satisfy $lind_q(G)\leq k$. Particularly, we obtain new lower bounds on $lind_q(G)$. Our next result is about the computational complexity of scalar linear index of a digraph. It is known that deciding whether the scalar linear index of an undirected graph is equal to $k$ or not is NP-complete for $k\ge 3$ and is polynomially decidable for $k=1,2$ [3]. For digraphs, it is shown in [6] that for the binary alphabet, the decision problem for $k=2$ is NP-complete. We use graph homomorphism framework to extend this result to arbitrary alphabet.
On Index Coding and Graph Homomorphism
Javad B. Ebrahimi,Mahdi Jafari Siavoshani
Computer Science , 2014,
Abstract: In this work, we study the problem of index coding from graph homomorphism perspective. We show that the minimum broadcast rate of an index coding problem for different variations of the problem such as non-linear, scalar, and vector index code, can be upper bounded by the minimum broadcast rate of another index coding problem when there exists a homomorphism from the complement of the side information graph of the first problem to that of the second problem. As a result, we show that several upper bounds on scalar and vector index code problem are special cases of one of our main theorems. For the linear scalar index coding problem, it has been shown in [1] that the binary linear index of a graph is equal to a graph theoretical parameter called minrank of the graph. For undirected graphs, in [2] it is shown that $\mathrm{minrank}(G) = k$ if and only if there exists a homomorphism from $\bar{G}$ to a predefined graph $\bar{G}_k$. Combining these two results, it follows that for undirected graphs, all the digraphs with linear index of at most k coincide with the graphs $G$ for which there exists a homomorphism from $\bar{G}$ to $\bar{G}_k$. In this paper, we give a direct proof to this result that works for digraphs as well. We show how to use this classification result to generate lower bounds on scalar and vector index. In particular, we provide a lower bound for the scalar index of a digraph in terms of the chromatic number of its complement. Using our framework, we show that by changing the field size, linear index of a digraph can be at most increased by a factor that is independent from the number of the nodes.
Improvment of Free Convection Heat Transfer Rateof Rectangular Heatsink on Vertical Base Plates  [PDF]
HamidReza Goshayeshi, Mahdi Fahiminia, Mohammad Mahdi Naserian
Energy and Power Engineering (EPE) , 2011, DOI: 10.4236/epe.2011.34064
Abstract: In this paper, the laminar heat transfer of natural convection on vertical surfaces is investigated. Most of the studies on natural convection have been considered constantly whereas velocity and temperature domain, do not change with time, transient one are used a lot. Governing equations are solved using a finite volume approach. The convective terms are discretized using the power-law scheme, whereas for diffusive terms the central difference is employed. Coupling between the velocity and pressure is made with SIMPLE algorithm. The resultant system of discretized linear algebraic equations is solved with an alternating direction implicit scheme. Then a configuration of rectangular fins is put in different ways on the surface and heat transfer of natural convection on these surfaces without sliding is studied and finally optimization is investigated.
A New Method of Voiced/Unvoiced Classification Based on Clustering  [PDF]
Mojtaba Radmard, Mahdi Hadavi, Mohammad Mahdi Nayebi
Journal of Signal and Information Processing (JSIP) , 2011, DOI: 10.4236/jsip.2011.24048
Abstract: In this paper, a new method for making v/uv decision is developed which uses a multi-feature v/uv classification algorithm based on the analysis of cepstral peak, zero crossing rate, and autocorrelation function (ACF) peak of short-time segments of the speech signal by using some clustering methods. This v/uv classifier achieved excellent results for identification of voiced and unvoiced segments of speech.
Craniofacial Forms among Three Dominant Ethnic Groups of Gombe State, Nigeria
Maina,M. B; Mahdi,O; Kalayi,G. G;
International Journal of Morphology , 2012, DOI: 10.4067/S0717-95022012000100038
Abstract: anthropometric measurements such as cranial and facial forms provide essential information that can be used added provide in orofacial surgery and in diagnostic comprehension between patient and normal populations. there is no published literature about the types of head and face shapes in fulani, tangale and tera ethnic groups of nigeria. hence, this study was undertaken to document the various cranial and facial forms of these ethnic groups residing in gombe region of north-eastern nigeria. head length, head width, head circumference, face length and face width were measured and the cephalic and prosopic indices calculated in a total of 300 subjects (150 males and 150 females). results analyzed placed all males of the three ethnic groups in dolicocephalic head group with mean cephalic indices lower than 74.9, while all females to mesocephalic head group with mean cephalic indices between the range of 75-79.9. on the basis of face shapes, the fulani and tera males were found to belong to hyperleptoprosopic group, while the tangale and tera females to leptoprosopic group with prosopic indices over 95 and between the ranges of 90-94.9, respectively. therefore, the findings revealed that all males and females of the three ethnic groups share close similarities in head types and some variations in face types. furthermore, variation of head and face shapes from this study exists with those of other studies within and outside nigeria.
Elimination Phase of Measles: an Epidemiological Survey in Gonabad (Iran) During 2006-2010
Hamed Ramezani A,Alireza Atarodi B,Mahdi Moshki
Iranian Journal of Pediatrics , 2012,
Abstract:
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