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Search Results: 1 - 10 of 149 matches for " Behnaz Seyfi "
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A Biomechanical Model of Human Lung Deformation Utilizing Patient-Specific Elastic Property  [PDF]
Behnaz Seyfi, Anand P. Santhanam, Olusegun J. Ilegbusi
Journal of Cancer Therapy (JCT) , 2016, DOI: 10.4236/jct.2016.76043
Abstract: A biomechanical model is developed and validated for breathing-induced deformation of human lung. Specifically, a subject-specific poro-elastic lung model is used to predict the displacement over the breathing cycle and compared with displacement derived from high resolution image registration. The lung geometry is derived from four-dimensional computed tomography (4DCT) scan dataset of two human subjects. The heterogeneous Young’s modulus is estimated using inverse analysis method. The numerical simulation uses fluid-structure interaction technique to solve the coupled airflow equations and structural dynamics of the lung tissue. The modelled displacement is validated by comparison with the 4DCT registration results.
Modeling Airflow Using Subject-Specific 4DCT-Based Deformable Volumetric Lung Models
Olusegun J. Ilegbusi,Zhiliang Li,Behnaz Seyfi,Yugang Min,Sanford Meeks,Patrick Kupelian,Anand P. Santhanam
International Journal of Biomedical Imaging , 2012, DOI: 10.1155/2012/350853
Abstract: Lung radiotherapy is greatly benefitted when the tumor motion caused by breathing can be modeled. The aim of this paper is to present the importance of using anisotropic and subject-specific tissue elasticity for simulating the airflow inside the lungs. A computational-fluid-dynamics (CFD) based approach is presented to simulate airflow inside a subject-specific deformable lung for modeling lung tumor motion and the motion of the surrounding tissues during radiotherapy. A flow-structure interaction technique is employed that simultaneously models airflow and lung deformation. The lung is modeled as a poroelastic medium with subject-specific anisotropic poroelastic properties on a geometry, which was reconstructed from four-dimensional computed tomography (4DCT) scan datasets of humans with lung cancer. The results include the 3D anisotropic lung deformation for known airflow pattern inside the lungs. The effects of anisotropy are also presented on both the spatiotemporal volumetric lung displacement and the regional lung hysteresis. 1. Introduction Lung radiotherapy aims at delivering therapeutic ionizing radiation on lung tumor in the form of external beams from different angles while minimizing exposure to surrounding healthy tissues. Errors in the lung tumor localization during therapy may lead to an undertreatment of the tumor and an overexposure of ionizing radiation to the surrounding lung tissues [1]. Lung tumor localization errors occur as the lung deforms during breathing, thereby compromising the accuracy of the radiation therapy [2]. Clinical approach to address these localization errors typically involves increasing tumor margins in radiation treatment plan and avoiding voluntary breathing variations (e.g., sneezing and coughing) [3]. A precise estimation of lung tumor position can be facilitated by a fluid structure interaction model, where the airflow inside the lungs is modeled using computational fluid dynamics (CFD) techniques, and the structure is modeled as a subject-specific anisotropic poroelastic medium. Such an estimation of the lung tumor position will not only lead to improved adaptive radiotherapy and treatment outcomes but also lead to an improved image acquisition guidance in the future. CFD of airflow inside lungs during respiration is a challenging task due to the complexity of lung geometry, structural heterogeneity and material anisotropy, and other boundary constraints [4]. Specifically, the human lung is heterogeneous and anisotropic, with a wide range of elastic property values [5]. This situation is further
Call Admission Control in HAP W-CDMA Cellular Systems  [PDF]
Behnaz Behzadi
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2013, DOI: 10.4236/ijcns.2013.68040
Abstract:

Among various radio sources which control different dependencies/functions, in this article, we will talk about the Call Admission Control (CAC), and we are supposed to confine our concentration on W-CDMA which is based on high raised platforms, since during the recent years remarkable amount of attention has been focused on platforms located in stratosphere layer [1]. Firstly, we study the capacity of uplink from HAP (High Altitude Platform) W-CDMA and we’ll work on estimation and power control defects in a new conversation added to current conversations. We’ll enhance the Call Admission Control (CAC) based on the side effects of power control defects and users’ stimulus and then compare the CAC which has been measured by using of momentary energy on bit in the spectral density form (Eb/N0). Then we examine the mentioned charts for two different criteria which the decision will be made by these criteria in order to decide if exchanged calls are to be admitted or not. The first criterion is based on the minimum of (Eb/N0) of the first row cells meanwhile the second criterion is based on the average of (Eb/N0) of first row-cells.

Counting Multisections in Conic Bundles over a Curve defined over F_q
Seyfi Turkelli
Mathematics , 2008,
Abstract: For a given conic bundle X over a curve C defined over F_q, we count irreducible branch covers of C in X of degree d and height e>>1. As a special case, we get the number of algebraic numbers of degree d and height e over the function field F_q (C).
Connected Components of Hurwitz Schemes and Malle's Conjecture
Seyfi Turkelli
Mathematics , 2008,
Abstract: Let Z(X) be the number of degree-d extensions of F_q(t) with bounded discriminant and some specified Galois group. The problem of computing Z(X) can be related to a problem of counting F_q-rational points on certain Hurwitz spaces. Ellenberg and Venkatesh used this idea to develop a heuristic for the asymptotic behavior of Z'(X), the number of -geometrically connected- extensions, and showed that this agrees with the conjectures of Malle for function fields. We extend Ellenberg-Venkatesh's argument to handle the more complicated case of covers of P^1 which may not be geometrically connected, and show thatthe resulting heuristic suggests a natural modification to Malle's conjecture which avoids the counterexamples, due to Kl\"uners, to the original conjecture.
Splitting of Sharply 2-Transitive Groups of Characteristic 3
Seyfi Turkelli
Mathematics , 2008,
Abstract: We give a group theoretic proof of the splitting of sharply 2-transitive groups of characteristic 3.
A Focused Crawler Combinatory Link and Content Model Based on T-Graph Principles
Ali Seyfi
Computer Science , 2013, DOI: 10.1016/j.csi.2015.07.001
Abstract: The two significant tasks of a focused Web crawler are finding relevant topic-specific documents on the Web and analytically prioritizing them for later effective and reliable download. For the first task, we propose a sophisticated custom algorithm to fetch and analyze the most effective HTML structural elements of the page as well as the topical boundary and anchor text of each unvisited link, based on which the topical focus of an unvisited page can be predicted and elicited with a high accuracy. Thus, our novel method uniquely combines both link-based and content-based approaches. For the second task, we propose a scoring function of the relevant URLs through the use of T-Graph (Treasure Graph) to assist in prioritizing the unvisited links that will later be put into the fetching queue. Our Web search system is called the Treasure-Crawler. This research paper embodies the architectural design of the Treasure-Crawler system which satisfies the principle requirements of a focused Web crawler, and asserts the correctness of the system structure including all its modules through illustrations and by the test results.
Analysis and Evaluation of the Link and Content Based Focused Treasure-Crawler
Ali Seyfi
Computer Science , 2013, DOI: 10.1016/j.csi.2015.09.007
Abstract: Indexing the Web is becoming a laborious task for search engines as the Web exponentially grows in size and distribution. Presently, the most effective known approach to overcome this problem is the use of focused crawlers. A focused crawler applies a proper algorithm in order to detect the pages on the Web that relate to its topic of interest. For this purpose we proposed a custom method that uses specific HTML elements of a page to predict the topical focus of all the pages that have an unvisited link within the current page. These recognized on-topic pages have to be sorted later based on their relevance to the main topic of the crawler for further actual downloads. In the Treasure-Crawler, we use a hierarchical structure called the T-Graph which is an exemplary guide to assign appropriate priority score to each unvisited link. These URLs will later be downloaded based on this priority. This paper outlines the architectural design and embodies the implementation, test results and performance evaluation of the Treasure-Crawler system. The Treasure-Crawler is evaluated in terms of information retrieval criteria such as recall and precision, both with values close to 0.5. Gaining such outcome asserts the significance of the proposed approach.
Numerical Computing of Reduction of SAR Values in a Homogenous Head Model Using Copper Shield
Levent Seyfi,Ercan Yaldiz
Lecture Notes in Engineering and Computer Science , 2010,
Abstract:
Analysis and Evaluation of Four Negative Characters of Championship Era (Jamasp – Soodabeh)
Behnaz Shahnavazi
English Language and Literature Studies , 2013, DOI: 10.5539/ells.v3n3p96
Abstract: The Sage Abolqasem Ferdowsi is on of the first-grade stars of Iran Literature and Culture who became populated in historical past era by his worthwhile book, Shahnameh, and his extensively clear life was sank in a mist of gloom and unfamiliarity. Despite all the emphasis on avoiding bad behaviors and sin in national Shahnameh, many of the actors of it, even kings and heroes, who are made and processed by wishes and myths, are not defect-free and are infected somehow to sin. Even World Champion, Rustam, who is the main part of Ferdowsi’ performance in Iran national epic, is finally killed by unfair tip and trick of his brother. This fact indicates the tangible nature of personalities in Shahnameh and the reason of their influence on peple. As, moral and educational perfections enable people reaching higher levels and vice versa, badness leads to afoul in whirpool of distruction. And Ferdowsi, parallel to narrative these stories has tried to write out the national epic via the most frightful tragedies and murderous and informative events, and at the end, beautifully visualizes his internal utopia and in order to mount the highest glory of ideal human esteem, reached the top mountain on which human knowledge and capability was created.
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