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Search Results: 1 - 10 of 229 matches for " Saberi "
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Throughput Maximizing Frequency and Power Scheduling for Wireless Ad-Hoc Networks in the Low-SINR Regime  [PDF]
Nahid Saberi
Wireless Engineering and Technology (WET) , 2012, DOI: 10.4236/wet.2012.33017
Abstract: We study the problem of frequency and power allocation and scheduling at a time-slotted cognitive ad-hoc wireless network, where cognitive nodes share a number of frequency bands and frequency reuse is allowed. In such a network the throughput maximization problem generally results in a mixed zero-one nonlinear non-convex problem. Interestingly, in the low-SINR regime, the power allocation policy that maximizes the total throughput follows an “on/off” strategy with maximum power usage in the “on” state. In this paper we show that the on/off strategy in the low-SINR regime is also optimal with respect to throughput when scheduling users over time and frequency subject to minimum SINR requirements. We show that these additional constraints will not change the optimum strategy, but may affect the set of “on” or “off” transmitters. Also we present an approach that transforms the mixed zero-one nonlinear problem to an equivalent mixed zero-one linear problem at the expense of extra variables.
On the Homotopy Analysis Method and Optimal Value of the Convergence Control Parameter: Solution of Euler-Lagrange Equation  [PDF]
Jafar Saberi-Nadjafi, Reza Buzhabadi, Hassan Saberi Nik
Applied Mathematics (AM) , 2012, DOI: 10.4236/am.2012.38129
Abstract: This paper presents, an efficient approach for solving Euler-Lagrange Equation which arises from calculus of variations. Homotopy analysis method to find an approximate solution of variational problems is proposed. An optimal value of the convergence control parameter is given through the square residual error. By minimizing the the square residual error, the optimal convergence-control parameters can be obtained. It is showed that the homotopy analysis method was valid and feasible to the study of variational problems.
Effect of Beam Length and Braced Length on Moment-Rotation Behavior of Castellated Beams  [PDF]
Mohsen Gerami, Hamid Saberi, Vahid Saberi, Ashkan Firouzi
Open Journal of Safety Science and Technology (OJSST) , 2013, DOI: 10.4236/ojsst.2013.33005
Abstract:

The presence of web openings in castellated beams introduces different modes of failure at the perforated sections such as excessive stresses in tee-sections, excessive stresses in mid-depth of the web post, web-post buckling, developing plastic Vierendeel mechanism. This paper presents nonlinear behavior of castellated beams under moment gradient loading and investigates the effect of beam length and braced length on moment-rotation behavior and ductility of this type of beams. Accuracy of finite element models of plain-webbed beams is evaluated comparing moment-rotation behavior and failure mode of other researchers’ numerical models and cleared a satisfactory accuracy. Rotational capacity of castellated beams, derived from numerical modeling, is compared with corresponding I-shaped plain-webbed steel beams and it is cleared that for the short beams, web openings reduce energy absorbance and plastic moment capacity of the beams more than long ones.

Numerical Evaluation of Symmetric Prism Method to Analyze the Splitting Forces Due to TBM Jack Loads  [PDF]
Hamid Saberi, Vahid Saberi, Ali Kheyroddin, Ashkan Firouzi
Open Journal of Safety Science and Technology (OJSST) , 2013, DOI: 10.4236/ojsst.2013.33006
Abstract:

Final lining in mechanized excavation includes the precast concrete segments. These segments are designed for applied loads during construction, moving, depot, assembling in the tunnel and service loads that are affected by earth conditions. One of these loads that are applied to the segments after assembling in the ring, are TBM jack loads especially when the TBM should excavate squeeze zones with single mode. As the jack pad section is smaller than the segment section, it causes splitting loads in the segment. Symmetric prism method is an approximate solution to evaluate these forces. In this paper, calculated results by this method are compared to that of numerical solution by ANSYS software. It shows 10 - 20 percent difference between numerical and analytical results.

"Intracerebral pneumatocele following non-penetrating head injury: Report of a case "
"Saberi H "
Acta Medica Iranica , 2000,
Abstract: Non-penetrating head injuries associated with skull base fractures can lead to the development of pneumocephalus upon airs ingress, which leads its course in the subarachnoid space. Intracerebral air accumulation is rare and ensuses when a paranasal sinus fracture is associated with a ensues when a paranasal sinus fracture is associated with a nearby parenchymal contusion. A 25-year old man is being presented with complaints of severe headaches and CSF rhinorrhea 2 months following head trauma. Intraparenchymal air entrapment was observed on computed tomogram. Surgical intervention was required to alleviate the symptoms. Surgical drainage and dural defect repair seems warranted for symptomatic intracerebral pneumatoceles to circumvent the on growing pathological sequel.
Comparison of Pb2+ Removal Efficiency by Zero Valent Iron Nanoparticles and Ni/Fe Bimetallic Nanoparticles
Ali Saberi
Iranica Journal of Energy and Environment (IJEE) , 2012,
Abstract: In this study, synthesized bimetallic Ni/Fe nanoparticles and zero-valent iron nanoparticles (nZVI) were investigated for remediation of Pb2+ against the effect of various parameters such as pH, volume to mass (V/m) ratio, contact time, initial concentration of Pb2+ on removal efficiency. Results of the present project suggest both Ni/Fe bimetallic nanoparticles and nZVI adsorbents have shown maximum removal of Pb2+ at pH 5 with an increasing trend with increasing pH. The V/m ratio optimization study reveals that the same volume of the lead solution requires more Ni/Fe bimetallic nanoparticles than nZVI. The time to achieve equilibrium is same in both the cases. Similarly, decrease in the removal efficiency with increase in initial concentration of Pb2+ is observed in both the cases.
Ancilla-assisted sequential approximation of nonlocal unitary operations
Hamed Saberi
Physics , 2011, DOI: 10.1103/PhysRevA.84.032323
Abstract: We consider the recently proposed "no-go" theorem of Lamata et al [Phys. Rev. Lett. 101, 180506 (2008)] on the impossibility of sequential implementation of global unitary operations with the aid of an itinerant ancillary system and view the claim within the language of Kraus representation. By virtue of an extremely useful tool for analyzing entanglement properties of quantum operations, namely, operator-Schmidt decomposition, we provide alternative proof to the "no-go" theorem and also study the role of initial correlations between the qubits and ancilla in sequential preparation of unitary entanglers. Despite the negative response from the "no-go" theorem, we demonstrate explicitly how the matrix-product operator(MPO) formalism provides a flexible structure to develop protocols for sequential implementation of such entanglers with an optimal fidelity. The proposed numerical technique, that we call variational matrix-product operator (VMPO), offers a computationally efficient tool for characterizing the "globalness" and entangling capabilities of nonlocal unitary operations.
Genuine fidelity gaps associated with a sequential decomposition of genuinely entangling isometry and unitary operations
Hamed Saberi
Physics , 2013, DOI: 10.1103/PhysRevA.88.062315
Abstract: We draw attention to the existence of "genuine" fidelity gaps in an ancilla-assisted sequential decomposition of genuinely entangling isometry and unitary operations of quantum computing. The gaps arise upon a bipartite decomposition of a multiqubit operation in a one-way sequential recipe in which an ancillary system interacts locally and only once with each qubit in a row. Given the known "no-go" associated with such a theoretically and experimentally desirable decomposition, various figures of merit are introduced to analyze the optimal "fidelity" with which an arbitrary genuinely entangling operation may admit such a sequential decomposition. An efficient variational matrix-product-operator (VMPO) protocol is invoked in order to obtain numerically the minimal values of the fidelity gaps incurred upon sequential decomposition of genuine entanglers. We term the values of the gaps so obtained genuine in the light of possible connections to the concept of the genuine multipartite entanglement and since they are independent of the ancilla dimension and the initial states the associated unitaries act upon.
Analyzing the Stability of a n-DOF System with Viscous Damping  [PDF]
Hashem Saberi Najafi, Amir Hosein Refahi Sheikhani
Applied Mathematics (AM) , 2011, DOI: 10.4236/am.2011.28129
Abstract: In this paper we introduce a numerically stable method for determining the stability of n-DOF system without computing eigenvalues. In this sense, at first we reduce the second-order system to a standard eigenvalue problem with symmetric tridiagonal form. Then we compute the exact inertia by using an algorithm based on floating point arithmetic [1]. Numerical tests report the effectiveness of these methods.
The Construction and Standardization of a Domestic Violence Questionnaire  [PDF]
Khadijeh Abolmaali, Hayedeh Saberi, Sousan Saber
Sociology Mind (SM) , 2014, DOI: 10.4236/sm.2014.41007
Abstract:

The purpose of this research was to standardize the self-reported domestic violence scale. 530 participants were randomly selected via clustered sampling methods from married students of The Islamic Azad University of district 8 in Iran. According to this scale, a total score was measured for domestic violence and also, based on exploratory factor analysis, 2 scores were measured for two dimensions of domestic violence, and these dimensions are: 1) Psycho-physical violence, 2) Control violence (sexual, economic, coercive violence). The reliability of this test was measured with internal consistency (α = 0.915) and the test retest method (r = 0.987). The criterion validity of this scale was significant and this scale had a significant relationship with the quality of marital life test. This scale can be used by psychologists and researchers for diagnostic assessment, intervening programs and identification of domestic violence dimensions.

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