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razavi-satvati--reyhaneh-sadat
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Enhancement Of the Quality In PET Brain Images Using AutoGANcoder Algorithms
, M.Sc. Thesis Sharif University of Technology ; vosoughi, Naser (Supervisor) ; Ghafarian, Pardis (Co-Supervisor) ; Attari, Ali Akbar (Co-Supervisor)
Abstract
Positron Emission Tomography (PET) is a cutting-edge medical imaging technique that enables the examination of functional activities in different regions of the body, particularly the brain. This technique involves injecting a radiopharmaceutical into the body, which emits gamma rays that are subsequently detected by the PET scanner to generate images. However, a significant challenge in PET imaging is the degradation of image quality due to noise and photon scattering, which can lead to diagnostic errors, especially in sensitive applications such as detecting brain diseases. Various image reconstruction techniques have been developed in the past to mitigate attenuation and scattering...
Cluster-based adaptive SVM: a latent subdomains discovery method for domain adaptation problems
, Article Computer Vision and Image Understanding ; Volume 162 , 2017 , Pages 116-134 ; 10773142 (ISSN) ; Jamzad, M ; Sharif University of Technology
2017
Abstract
Machine learning algorithms often suffer from good generalization in testing domains especially when the training (source) and test (target) domains do not have similar distributions. To address this problem, several domain adaptation techniques have been proposed to improve the performance of the learning algorithms when they face accuracy degradation caused by the domain shift problem. In this paper, we focus on the non-homogeneous distributed target domains and propose a new latent subdomain discovery model to divide the target domain into subdomains while adapting them. It is expected that applying adaptation on subdomains increase the rate of detection in comparing with the situation...
Indoor Noise Pollution Modeling: A Case Study on Resalat Tunnel
, M.Sc. Thesis Sharif University of Technology ; Vaziri, Manouchehr (Supervisor)
Abstract
Noise or noise pollution, is defined as an unwanted sound, produced mostly by motor vehicles in urban areas. If the noise exceeds its limit, adverse effects on users and citizens are expected. Thus the assessment of the noise level and its comparison with allowable values is mandatory. Traffic induced noise depends upon different factors such as traffic, weather, and, sound barriers. Noise pollution study has a long history all over the world. Many studies, mostly representing the outdoor noise pollution models, have been done in recent years. This paper presents an assessment of traffic-induced noise in a heavily traveled tunnel, locally referred to as Resalat tunnel, which is located in...
The Effect of Travel Time Reliability on Morning Peak Travellers route choice in Large Metropolitan Area
, M.Sc. Thesis Sharif University of Technology ; Poorzahedy, Hossein (Supervisor)
Abstract
Data collected from street networks show that travel time in urban street networks is a stochastic variable, whose range of variation increases with the congestion level. Work and school trips comprise the major part of morning peak volumes, whose common characteristic is that they need to be made on time. For this reason, these travelers are pessimistic in their route choice, and try to choose routes which are more reliable. Travel time standard deviation is one of the common measures for estimating travel time reliability that is related to properties of day-to-day travel time distribution on a particular route. Based on the empirical data collected from Tehran street network, this paper...
Design and Implementation of a FlexRay Transceiver
, M.Sc. Thesis Sharif University of Technology ; Atarodi, Mojtaba (Supervisor)
Abstract
With the advancement of automotive industry, the number of electronic systems that need to communicate with each other has increased. An effective strategy to meet these growing demands is using bus-based protocols, which can establish safe communication among numerous nodes with reasonable cost, weight, and space requirements. The objective of this thesis is the design and implementation of a transceiver based on the FlexRay protocol. The significance of this protocol lies in its ability to provide higher data transmission rates compared to other protocols like CAN and LIN, and its role as the foundational communication medium among various domains in modern vehicle architectures. In this...
Using Information Beyond Text to Generate Language Embedding Vectors
, M.Sc. Thesis Sharif University of Technology ; Sameti, Hossein (Supervisor)
Abstract
In this thesis, we introduce a novel Artificial Intelligence (AI) system inspired by the philosophical and psychoanalytical concept of imagination as a ``Re-construction of Experiences". Our AI system is equipped with an imagination-inspired module that bridges the gap between textual inputs and other modalities, enriching the derived information based on previously learned experiences. A unique feature of our system is its ability to formulate independent perceptions of inputs. This leads to unique interpretations of a concept that may differ from human interpretations but are equally valid, a phenomenon we term as ``Interpretable Misunderstanding". We employ large-scale models,...
Entanglement Distillation for Weakly Entangled States
, M.Sc. Thesis Sharif University of Technology ; Mirkamali, Maryam Sadat (Supervisor)
Abstract
Quantum entanglement is an essential resource in quantum information processing, such as quantum communication and quantum computing. Although entanglement is critical for practical implementations in these fields, creating and transmitting entanglement without altering the states is challenging. External noise may destroy or weaken the entanglement. Consequently, there is a need for methods to improve entanglement. Entanglement distillation is an effort to address this issue. It is a process where, probabilistically, a smaller number of strongly entangled states are created from a fixed number of noisy entangled states. This process is carried out using only local operations and classical...
Capacity-outage joint analysis and optimal power allocation for wireless body area networks
, Article IEEE Systems Journal ; 2018 ; 19328184 (ISSN) ; Jahed, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
Wireless body area networks (WBANs) are characterized by short-range wireless communication between inherently resource-limited sensors that operate in the vicinity of the human body for recording certain physiological signals. One of the main limitations of WBANs is in terms of their available power. Since the nodes are typically battery-driven, an efficient power transmission is essential to guarantee long-lasting communications among nodes without the need for frequent battery replacement or charging. In this study, aiming to improve the WBAN performance, we first investigate the power allocation problem by choosing the ergodic capacity and the outage probability as the desired metrics....
Channel modeling and reliability assessment for body-centric wireless communications
, Article 2017 25th Iranian Conference on Electrical Engineering, ICEE 2017, 2 May 2017 through 4 May 2017 ; 2017 , Pages 1-7 ; 9781509059638 (ISBN) ; Jahed, M ; Sharif University of Technology
2017
Abstract
Wireless Body Area Networks (WBANs) are one of the emerging technological trends that have gained a lot of attention both from academic and industrial domains. WBAN, as standardized by IEEE 802.15.6, is a network composed of intelligent, miniaturized, low power nodes that are implanted in, placed on or in close proximity of human body for certain healthcare applications. Sensors send their acquired data to a central hub wirelessly for further processing. In this paper, based on a publicly available channel data set, we investigate the applicable channel models in a typical WBAN. Considering various scenarios with different carrier frequencies, bandwidths, body movements, and transceiver...
Node positioning and lifetime optimization for wireless body area networks
, Article IEEE Sensors Journal ; Volume 17, Issue 14 , 2017 , Pages 4647-4660 ; 1530437X (ISSN) ; Jahed, M ; Sharif University of Technology
2017
Abstract
Wireless communication networks may be categorized based on the extent of the geographical area that they cover. The latest trend in this assortment is wireless body area network (WBAN), which is standardized by IEEE 802.15.6 and is defined as a network composed of intelligent, miniaturized, low-power nodes that are implanted in, placed on, or in close proximity to the human body for certain healthcare applications. In this paper, we will start with some assessments on applicable channel models for a typical WBAN. Considering various scenarios with different carrier frequencies, bandwidths, body movements, and transceiver locations, the well-known Bayesian Information Criterion is used to...
Constrained error rate analysis for wireless body area networks
, Article IET Wireless Sensor Systems ; Volume 9, Issue 6 , 2019 , Pages 366-374 ; 20436386 (ISSN) ; Jahed, M ; Sharif University of Technology
Institution of Engineering and Technology
2019
Abstract
Wireless body area network (WBAN) is composed of miniaturised sensors that operate in the vicinity of the human body for recording the vital physiological signals and wirelessly transmitting them to a central hub for further processing. In this study, a statistical approach is applied to an experimental channel data set to extract the models for the squared channel gain that best describe the characteristics of the transmission medium between the sensors and the central hub. The derived models are then utilised to investigate the error rate performance of WBAN sensors. On the basis thereof, an optimisation problem is formed for which the cost function is the symbol error rate (SER) metric....
Capacity-outage joint analysis and optimal power allocation for wireless body area networks
, Article IEEE Systems Journal ; Volume 13, Issue 1 , 2019 , Pages 635-646 ; 19328184 (ISSN) ; Jahed, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
Wireless body area networks (WBANs) are characterized by short-range wireless communication between inherently resource-limited sensors that operate in the vicinity of the human body for recording certain physiological signals. One of the main limitations of WBANs is in terms of their available power. Since the nodes are typically battery-driven, an efficient power transmission is essential to guarantee long-lasting communications among nodes without the need for frequent battery replacement or charging. In this study, aiming to improve the WBAN performance, we first investigate the power allocation problem by choosing the ergodic capacity and the outage probability as the desired metrics....
Modeling of Damages such as Crack, Inclusions and Areas with Variable Properties in Composite and Metal Structures and then Prediction and Extension of their Life
, M.Sc. Thesis Sharif University of Technology ; Abedian, Ali (Supervisor)
Abstract
Nowadays, some of the major problems of the airplane industry is that airplanes’ fleet are approaching to the end of their defined life, inability to buy new planes and obtaining aircraft’s parts for repairing process. Therefore, in order to increase the life of the aging aircrafts, some essential process such as modeling processes, identify principal structure elements to strengthen and repair them should be done to all these airplanes, all these processes refer as aging process. Aging programs initiated in some countries, such as America, Australia, Britain and Canada from about thirty-five years ago, technological approaches inventing new ways to start repairing worn metallic structures...
Semi Solid Rheocasting of A356 Aluminum Alloy by High Speed Injection
, M.Sc. Thesis Sharif University of Technology ; Ashuri, Hossein (Supervisor)
Abstract
Aluminum is the lightest industrial element after magnesium. As a result, aluminum alloys have many industrial usages because of their high specific strength. Semisolid casting is one of the processes that is capable of producing aluminum alloys with high mechanical properties. In this process, there are a wide variety of methods to prepare semisolid slurry, one of the best ways of which to produce globular structure is electromagnetic stirrer. In this research, the semisolid slurry of A356 aluminum alloy is fabricated by electromagnetic stirrer under different conditions of stirrer intensity current, stirring time and pouring temperature. Then the fabricated semisolid slurry is injected...
Channel Modeling and Assessment of Key Performance Indicators for Wireless Body Area Networks
, Ph.D. Dissertation Sharif University of Technology ; Jahed, Mehran (Supervisor)
Abstract
Wireless Body Area Network (WBAN) is one of the emerging technological trends that paves the way for the next generation medical systems by offering proactive wellness management and early detection of diseases. WBAN, as standardized by IEEE 802.15.6, is a network composed of intelligent, miniaturized, low power sensors that are strategically implanted in, placed on, or in close proximity to the human body. The sensors have responsibility for recording vital physiological signals and wirelessly transmitting them to a central hub for further processing. In this study, we have first investigated the applicable channel models for a typical WBAN. Considering various scenarios with different...
Synthesis and Properties of Functional Super Hydrophobic TiO2
, M.Sc. Thesis Sharif University of Technology ; Dolati, Abolghasem (Supervisor)
Abstract
Titanium nano-oxide (TiO2) coatings have been used for self-cleaning, antimicrobial, and dust-proof designs. The degree of wetting of a solid surface with water in humid air depends on how the surface tension of the existing phases relates. The ratio between these tensions estimates the contact angle between a drop of water and the surface on which it is placed. A contact angle above 150 º is essential for surface overflow. In this study, 18 different combinations of titanium oxide and FAS, PDMS and PMS nanoparticles were obtained with a static contact angle of 165 to 150 º and a dynamic contact angle of 7 º.1 to 4.5 º. Following the measurement of water droplet slip speed on a sloping...
Ray Tracing Based on Reinforcement Learning
, M.Sc. Thesis Sharif University of Technology ; Moghadasi, Reza (Supervisor)
Abstract
We show that the equations of reinforcement learning and light transport simulation (rendering equation) are related integral equations. Based on this correspondence, a scheme to learn importance while sampling path space is derived. The new approach is demonstrated in a consistent ray tracing algorithm that uses reinforcement learning to progressively learn where light comes from. As using this information for importance sampling includes information about visibility, too, the number of light transport paths with non-zero contribution is dramatically increased, resulting in much less noisy images within a fixed time budget
Deformation and Annealing Behavior of an Austenitic Stainless Steel
, M.Sc. Thesis Sharif University of Technology ; Serajzadeh, Siamak (Supervisor)
Abstract
In this research, non-isothermal annealing process at temperatures ranging between 400°C to 830 °C was investigated in warm and cold-rolled austenitic stainless steel 304L. First, the wide variety of austenitic to martensitic structure was produced by the multi-pass rolling process at room temperature -8 °C, 200 °C, and 280°C. The n exponent in Olson-Cohen equation was governed 2.83 after non-linear curve fitting to assess the fraction of deformation-induced martensite as a function of strain. Afterward, Abaqus/Explicit method was utilized to achieve the stored energy and plastic strains distribution through the thickness. Then, Cellular automata and Galerkin-finite element models were...
The triangular pyramid: Routing and topological properties
, Article Information Sciences ; Vol. 180, issue. 11 , 2010 , p. 2328-2339 ; ISSN: 00200255 ; Sarbazi-Azad, H ; Sharif University of Technology
2010
Abstract
In this paper, a new topology for multicomputer interconnection networks, based on triangular mesh, is proposed. The new network, referred to as the triangular pyramid (or tripy for short), has L levels of triangular mesh. We study some basic important properties of the proposed network as well as introduce a routing algorithm for the tripy network based on the routing of triangular meshes. We prove that this form of pyramidal network is Hamiltonian, Hamiltonian-connected, and pancyclic. We also prove that the proposed network is 6-colorable and conduct a brief comparison of the tripy and its traditional pyramid counterpart. Our results show that the proposed network has higher scalability,...
Symbol error rate analysis and power allocation for decode and forward relaying with channel estimation error
, Article 2012 19th International Conference on Telecommunications, , 23 April 2012 through 25 April 2012, Jounieh ; 2012 ; 9781467307475 (ISBN) ; Pakravan, M. R ; Sharif University of Technology
IEEE
2012
Abstract
In this paper we study the statistical properties of the Signal to Noise Ratio (SNR) of the dual-hop relaying link in a cooperative wireless communication system in the presence of channel estimation errors for Decode and Forward (DF) relaying protocol. Then for assessment of the system performance the Symbol Error Rate (SER) is considered. Two approaches are introduced for SER calculation from which the second one results in a closed form solution. Finally the second approach is used to find an optimum power allocation scheme for transmission of pilot and data symbols at the source and the relay terminals that results in minimizing the SER and considerable amount of power saving. Also Monte...