Network Design Problem Considering Unsignalized Intersection Delay Function

, M.Sc. Thesis Sharif University of Technology Siyadati, Saba (Author) ; Zokaie Aashtiani, Hedayat (Supervisor)

Abstract

In a discrete network design problem (DNDP), an optimal set of projects is chosen from suggested projects to expand a transportation network. The optimal set is selected by minimizing the total travel time with respect to the budget constraint. This problem is formulated as a bi-level optimization. In the current study, traffic assignment is solved at the lower level as a user equilibrium problem by considering the delay of intersections which is the major portion of total intra-city travel time. This study investigates the performance of the transportation network with more realistic assumptions compared to the previous studies in the network design problem.This study uses the branch and...

Conjugate Residual Method for Large Scale Unconstrained Nonlinear Optimization

, M.Sc. Thesis Sharif University of Technology Siyadati, Maryam (Author) ; Mahdavi Amiri, Nezam (Supervisor)

Abstract

Nowadays, solving large-scale unconstrained optimization problems has wide applications in data science and machine learning. Therefore, the development and analysis of efficient algorithms for solving unconstrained optimization problems is of great interest. Line search and trust region are two general frameworks for guaranteeing the convergence of algorithms for solving unconstrained optimization problems. Conjugate gradient (CG) methods and the conjugate residual (CR) balance by Hestenes and Stiefel, have been presented for solving linear systems with symmetric and positive definite coefficient matrices. The basic feature of CR, that is, residual minimization, is important and can be used...

Wideband and narrowband circuit models for fano-shape guided-mode resonance

, Article IEEE Journal of Quantum Electronics ; Volume 55, Issue 3 , 2019 ; 00189197 (ISSN) Saba, A ; Memarian, M ; Mehrany, K ; Sharif University of Technology

Institute of Electrical and Electronics Engineers Inc 2019

Abstract

In this paper, we propose two different types of circuit models for Fano-shape guided-mode resonance (GMR) in waveguide gratings. Both the models constitute a resonant tank circuit together with a direct non-resonant channel between the incident and scattered light. One neglects the frequency dependence of the direct non-resonant channel and is only more accurate in the immediate vicinity of the Fano-type resonance. The other accounts for the frequency dependence of the direct non-resonant channel and thus remains accurate within a wider range of frequencies. The former being referred to as the narrow-band model is extremely accurate, insofar as the isolated GMR is of interest within a...

Wide-and narrow-band circuit models for fano-shape guided mode resonance

, Article IEEE Journal of Quantum Electronics ; 2019 ; 00189197 (ISSN) Saba, A ; Memarian, M ; Mehrany, K ; Sharif University of Technology

Institute of Electrical and Electronics Engineers Inc 2019

Abstract

In this paper, we propose two different types of circuit models for Fano-shape guided mode resonance (GMR) in waveguide gratings. Both models constitute a resonant tank circuit together with a direct non-resonant channel between the incident and the scattered light. One neglects the frequency dependence of the direct non-resonant channel and is only more accurate in the immediate vicinity of the Fano type resonance. The other accounts for the frequency dependence of the direct non-resonant channel and thus remains accurate within a wider range of frequencies. The former being referred to as the narrow-band model is extremely accurate insofar as the isolated GMR is of interest within a narrow...

Wide-and narrow-band circuit models for fano-shape guided mode resonance

, Article IEEE Journal of Quantum Electronics ; 2019 ; 00189197 (ISSN) Saba, A ; Memarian, M ; Mehrany, K ; Sharif University of Technology

Institute of Electrical and Electronics Engineers Inc 2019

Abstract

In this paper, we propose two different types of circuit models for Fano-shape guided mode resonance (GMR) in waveguide gratings. Both models constitute a resonant tank circuit together with a direct non-resonant channel between the incident and the scattered light. One neglects the frequency dependence of the direct non-resonant channel and is only more accurate in the immediate vicinity of the Fano type resonance. The other accounts for the frequency dependence of the direct non-resonant channel and thus remains accurate within a wider range of frequencies. The former being referred to as the narrow-band model is extremely accurate insofar as the isolated GMR is of interest within a narrow...

Range-free passive acoustic localization

, Article 2008 International Conference on Intelligent Sensors, Sensor Networks and Information Processing, ISSNIP 2008, Sydney, NSW, 15 December 2008 through 18 December 2008 ; 2008 , Pages 37-42 ; 9781424429578 (ISBN) Abrahami Saba, A ; Abolhassani, H ; Ghodsi, M ; Sharif University of Technology

2008

Abstract

We propose a range-free localization framework in which a network of randomly deployed acoustic sensors can passively use natural acoustic phenomena within its environment to localize itself. We introduce a novel approach for registration of sensors observations which takes advantage of a clustering technique on triplets of associated observations. A Bayesian filtering method is employed to incrementally improve system state estimation as more observations become available. To the best of our knowledge this is the first work done on range-free passive acoustic localization. Simulation experiments of the proposed algorithms are presented. © 2008 IEEE

Automatic Acoustic Localization in Sensor Networks Using Environmental Natural Acoustic Phenomena

, M.Sc. Thesis Sharif University of Technology Abrahimi Saba, Amin Reza (Author) ; Abolhassani, Hassan (Supervisor)

Abstract

We propose a range-free localization framework in which a network of randomly deployed acoustic sensors can passively use natural acoustic phenomena within its environment to localize itself. We introduce a novel approach for registration of sensors observations which takes advantage of a clustering technique on triplets of associated observations. A Bayesian filtering method is employed to incrementally improve system state estimation as more observations become available. To the best of our knowledge this is the first work done on range-free passive acoustic localization. Furthermore, we have proposed a simple but effective and efficient acoustic detection method which can be used to...

Two-dimensional edge detection by guided mode resonant metasurface

, Article IEEE Photonics Technology Letters ; Volume 30, Issue 9 , 1 May , 2018 , Pages 853-856 ; 10411135 (ISSN) Saba, A ; Tavakol, M. R ; Karimi Khoozani, P ; Khavasi, A ; Sharif University of Technology

Institute of Electrical and Electronics Engineers Inc 2018

Abstract

In this letter, a new approach to perform edge detection is presented using an all-dielectric complimentary metal-oxide-semiconductor-compatible metasurface. Our design is based on the guided-mode resonance, which provides a high quality factor resonance to make the edge detection experimentally realizable. The proposed structure is easy to fabricate, and it can be exploited for detection of edges in two dimensions due to its symmetry. In addition, a tradeoff between gain and the resolution of edge detection is discussed, which can be adjusted using appropriate design parameters. The proposed edge detector potentially can be used in ultrafast analog computing and image processing. ©...