CFD Simulation and Analysis of Heat Pipe Heat Exchanger Radiator

, M.Sc. Thesis Sharif University of Technology Abed Niari, Saeed (Author) ; Shafii, Mohammad Behshad (Supervisor)

Abstract

Due to the development of heat pipes in different industries and special characteristics of heat pipes, in this study, it has been tried using computational fluid dynamics (CFD) method to simulate a heat pipe heat exchanger that can be a replacement for the normal radiator. The experimental model of this heat exchanger has been tested at past studies and the numerical simulation of the heat exchanger will analyze at present study. The use of heat pipe in the car radiator has many advantages such as reducing fluid pressure drop through the heat exchanger, high reliability due to the particular structure of the heat exchanger (individual performance of each heat pipe) and improving heat...

A new achievable rate for a stochastic two relay network with no interference

, Article 2008 42nd Asilomar Conference on Signals, Systems and Computers, ASILOMAR 2008, Pacific Grove, CA, 26 October 2008 through 29 October 2008 ; June , 2008 , Pages 909-913 ; 10586393 (ISSN); 9781424429417 (ISBN) Abed Hodtani, G ; Sharif University of Technology

2008

Abstract

Gastpar and Vetterli named the adhoc networks with one randomly selected source-destination pair as relay networks and they suggested using arbitrary network coding in order to increase the overall efficiency Here, the relay network is investigated with two relays and no interference and a new achievable rate is obtained using a new network coding (decodeand-broadcast). The obtained achievable rate (i) gives the lower bound for the general relay channel, obtained by Cover and El Gamal, but with slight difference due to no interference assumption at the receiver (ii) includes the one relay rates of a two-level relay channel studied by Gupta and Kumar using point to point coding, (iii)...

Verification of OSPF vulnerabilities by colored petri net

, Article SIN 2013 - Proceedings of the 6th International Conference on Security of Information and Networks ; November , 2013 , Pages 102-109 ; 9781450324984 (ISBN) Niari, S. T ; Jahangir, A. H ; Sharif University of Technology

2013

Abstract

Routers and routing protocols are critical parts of a network infrastructure. OSPF is one of the most important routing protocols, and therefore its vulnerabilities can be very destructive. This makes its security analysis critical. There are many reported and potential vulnerabilities in OSPF protocol. Considering the complexity and the ambiguity of its description in RFC 2328, it is very valuable to design a formal model of the protocol and analyze the vulnerabilities of its critical parts. In this paper, some challenging parts of OSPF protocol along with attack scenarios are modeled by means of Colored Petri Net in CPN Tools environment. Then, the reported vulnerabilities are analyzed by...

Modeling Multi-path Covering Routing Problem

, M.Sc. Thesis Sharif University of Technology Rezapour Niari, Maryam (Author) ; Koorosh, Eshghi (Supervisor)

Abstract

The location problem is one of the main topics at the strategic level. This problem is investigated along with many areas such as network design and path covering problems. Routing between source and destination nodes is done in such a way that maximizes traffic coverage and reduces costs as much as possible. Routing problems are considered in goods distribution areas and urban transit systems. Goods distribution from set of cross-docks can help to reduce costs and improve resource efficiency. So, this topic is considered in this research and a suitable model is proposed. Defining and developing of the road and rail transportation networks are main topics in urban traffic management which...

Designing Supply Chain and Logistics Network with Multiple Objective Functions under Uncertainty

, M.Sc. Thesis Sharif University of Technology Safaei, Sepehr (Author) ; Rezapor Niari, Maryam (Supervisor)

Abstract

Wheat and flour are vital components of the food supply chain, and disruptions in their supply can have profound economic, social, and political impacts. This study focuses on optimizing the costs of the wheat and flour supply chain, encompassing production, imports, transportation, and shortages, while fostering economic and social development. A two-objective Mixed Integer Linear Programming (MILP) model is developed, integrating uncertainty through a two-stage stochastic programming approach based on scenarios. The augmented epsilon constraint method is utilized to address the bi-objective optimization problem. Key outcomes include identifying optimal locations for silo construction,...

Carbon and Proton Beams Acceleration by Ultrashort Intense Ti-sapphire Laser Pulse

, M.Sc. Thesis Sharif University of Technology Abed, Ali (Author) ; Sadighi Bonabi, Rasoul (Supervisor)

Abstract

Nowadays, improved laser technologies and ultra-short pulse generation yield Ion and proton accelerations through laser-plasma interaction that has attracted great interest among researchers. Laser-induced particle beam acceleration establishes unique features compared to previous traditional methods that make them an attractive research field. Interacting high-power lasers with a dense matter or plasmas would generate an electrostatic field up to a few TV/m that is suitable to provide accelerated ion beams even up to few tens of GeV within a small micrometer volume. While the accelerated ion beams possess outstanding features, challenges such as increasing ion energies, spatial-spectral...

Named Entity Recognition in Persian Language using Deep Learning

, M.Sc. Thesis Sharif University of Technology Abed Azad, Parham (Author) ; Beigy, Hamid (Supervisor)

Abstract

Named Entity Recognition (NER) is one of the most important tasks in natural language processing. Improving performance in this task benefits other tasks. However, with the rapid expansion of text volume and diversity, significant challenges have emerged in this area. This thesis proposes a model to address the problem of multi-domain Named Entity Recognition. Traditional approaches used for multi-domain NER often have considerable limitations. Training a single model for diverse domains does not yield optimal results, while using multiple large models can lead to resource constraints. Additionally, approaches based on generative models for non-English languages, such as Persian, which is...

Topology analysis of manufacturing service supply–demand hyper-network considering QoS properties in the cloud manufacturing system

, Article Robotics and Computer-Integrated Manufacturing ; Volume 72 , 2021 ; 07365845 (ISSN) Rezapour Niari, M ; Eshgi, K ; Fatahi Valilai, O ; Sharif University of Technology

Elsevier Ltd 2021

Abstract

Cloud Manufacturing (CMfg), a new manufacturing paradigm, enables an opportunity for manufacturing enterprises to respond to a wide variety of demands. The CMfg concept integrates the distributed resources and capacities in a shared economy, transfers them to the virtual manufacturing services with various quality of service (QoS) properties. These services are invoked to collaborate in producing customized demands with specific functional and non-functional properties. The operational perspective of the service-demand matching problem is considered more in the literature; however, it is a challenging problem in the CMfg ecosystem. This paper evaluates the service-demand matching problem...

Adaptive capacity management in cloud manufacturing hyper-network platform: Case of COVID-19 equipment production

, Article International Journal of Management Science and Engineering Management ; Volume 17, Issue 4 , 2022 , Pages 239-258 ; 17509653 (ISSN) Rezapour Niari, M ; Eshghi, K ; Fatahi Valilai, O ; Sharif University of Technology

Taylor and Francis Ltd 2022

Abstract

Cloud Manufacturing (CMfg) is a service-oriented manufacturing (SOM) paradigm that provides a dynamic, scalable, and virtualized working ecosystem. The CMfg collaborative structure can be modeled as a hyper-network-based service-demand matching architecture. It is enriched with quality of service (QoS) characteristics to produce customized products in a stable and reliable network. This stability should be considered in the overall manufacturing network mechanism. This paper has provided adaptive strategies utilizing available resources and capacities to enhance the system’s stability and reliability against the unexpected events. The capabilities of the enhanced framework are utilized to...

Using cloud manufacturing to establish an ecosystem network for COVID-19 ventilator production

, Article International Journal of Computer Integrated Manufacturing ; Volume 36, Issue 6 , 2023 , Pages 842-862 ; 0951192X (ISSN) Rezapour Niari, M ; Eshghi, K ; Fatahi Valilai, O ; Sharif University of Technology

Taylor and Francis Ltd 2023

Abstract

Cloud Manufacturing (CMfg) as a service-oriented manufacturing (SOM) paradigm promotes the paradigm of partnership and collaboration among the globally distributed resources. Like technology-based marketplaces, it can identify different suppliers, determine their available services, and assign them to the requested orders based on the service-demand matching mechanism. The dominant capabilities of the SOM as a service can provide a collaborative and flexible manufacturing network configuration. This paper has focused on developing a new CMfg architecture with a concentrating on collaborative concepts to elaborate the modular manufacturing through the virtual process. In this model, different...

Analysis and Evaluation of Router Security Based on a Routing Protocol

, M.Sc. Thesis Sharif University of Technology Tizpaz Niari, Saeed (Author) ; Jahangir, Amir Hossein (Supervisor)

Abstract

The importance of routers in information transfer among networks is critical. Thus, vulnerabilities and security deficiencies in routers and the related services like routing protocols can be destructive not only for some hosts, but also for the whole network. Hence, it is necessary that 1) vulnerabilities related to the routers and their services be evaluated and analyzed, and 2) the functional aspects of routers related to the vulnerabilities be formally modeled and analyzed. In this thesis, we present a method for the evaluation and the analysis of OSPF routing protocol from the security point of view. First, reported vulnerabilities on the OSPF are collected and evaluated by a...

Predicting the Price of Non-Fungible Tokens with a Machine Learning Approach

, M.Sc. Thesis Sharif University of Technology Fadaei Tafreshi, Ali (Author) ; Rezapour Niari, Maryam (Supervisor)

Abstract

In recent years, the popularity and applications of Non-Fungible Tokens (NFTs) have increased dramatically. For this reason, especially in the current decade, many researches have been conducted in different fields about the use of these tokens at the global level. One of the important and vital topics in the field of non-exchangeable tokens is the issues related to price prediction and the factors affecting their prices, which are mainly investigated using data analysis approaches. In this research, the factors affecting the price of non-exchangeable tokens of Bored Ape Yacht Club (BAYC) have been studied. These factors include traits, transaction data, rarity scores, transaction volume,...

Forecasting Tractor Demand in Two Major Agricultural Crop-Producing Provinces of Iran

, M.Sc. Thesis Sharif University of Technology Vakili, Sepideh Sadat (Author) ; Rezapour Niari, Maryam (Supervisor)

Abstract

Today, demand function forecasting is one of the fundamental and critical challenges in organizational decision-making at both strategic and operational levels. Key decisions that significantly impact the success or failure of organizations -such as pricing, production planning, resource allocation, and market development- are directly influenced by the accuracy of demand forecasting. Since the demand function is typically affected by multiple factors including price, quality, economic conditions, social factors, and other variables shaping customer behavior, precise estimation requires employing diverse and accurate methods. Various approaches have been proposed in the literature for demand...

Multiuser detector for airborne co-located multiple input/multiple output radar using compressive measurements

, Article IET Radar, Sonar and Navigation ; Volume 11, Issue 2 , 2017 , Pages 260-268 ; 17518784 (ISSN) Abed, A. M ; Salehi, J. A ; Hariri, A ; Sharif University of Technology

Institution of Engineering and Technology 2017

Abstract

This study presents and analyses a novel joint detection and parameters estimation of multiple targets using a co-located multiple input/multiple output radar with moving platform, in the presence of clutter and background noise. A notable feature of the proposed approach is that clutter cancellation is independent of received data. Moreover, to decrease the computational load, the authors propose to perform the target detection and parameters estimation by directly processing on the compressive measurements as opposed to Nyquist samples. © The Institution of Engineering and Technology

The contagion effects of global financial crisis on Tehran Stock Exchange

, M.Sc. Thesis Sharif University of Technology Moghareh Abed, Sepehr (Author) ; Keshavarz Haddad, Gholamreza (Supervisor)

Abstract

US 2008 financial crisis, spread across the international stock markets in the second half of the year 2008. The crisis decreased the returns and increased the volatilities of almost all of the stock indices, however, its effects on Iran’s stock markets were unexplored. Financial limitations create an exclusive situation in Iran’s stock market. Using weekly data on the stock indices from July 2006 through August 2009, this study aims to exam in the contagion effects of the global financial crisis through the main indices such as S&P500 and FTSE100 on Tehran Stock Exchange indices: industrial and financial intermediary indices and The First and the Second indices of Tehran’s Stock Exchange....

Capacity of Almost General Relay Channel and Aref Network with Random Links

, Ph.D. Dissertation Sharif University of Technology Abed Hodtani, Ghosheh (Author) ; Aref, Mohammad Reza (Supervisor)

Abstract

First, we review in an appropriate way the researches regarding building blocks of a wireless network (Shannon channel, multiple access channel, broadcast channel, interference channel, relay channel) and then: • We consider two cases for a relay and describe the essential role of the relay with three Markovity conditions; define Almost General Relay Channel with Decode-And-Forward (AGRCDAF) strategy and determine its capacity. Then, we prove that our capacity theorem not only includes all known capacity theorems as its special cases but also potentially is applicable to other relay channels and is validated by its consistency with previous results related to special cases of broadcast and...

Developing Mathematical Model for Service-Demand Matching in Cloud Manufacturing Network

, Ph.D. Dissertation Sharif University of Technology Rezapour Niari, Maryam (Author) ; Eshghi, Kourosh (Supervisor) ; Fatahi Valilai, Omid (Supervisor)

Abstract

Cloud Manufacturing (CMfg) is a service-oriented manufacturing (SOM) paradigm that provides a dynamic, scalable, and virtualized working ecosystem. The CMfg collaborative structure can be modeled as a hyper-network-based service-demand matching architecture. It is enriched with quality of service (QoS) characteristics to produce customized products in a stable and reliable network. This stability should be considered in the overall manufacturing network mechanism. This Thesis has developed a multi-dimentional model and improved it by providing absorptive and adaptive strategies utilizing available resources and capacities to enhance the system’s stability and reliability against the...

Discrete scale invariance and its logarithmic extension

, Article Nuclear Physics B ; Volume 655, Issue 3 , 2003 , Pages 342-352 ; 05503213 (ISSN) Abed Pour, N ; Aghamohammadi, A ; Khorrami, M ; Rahimi Tabar, M. R ; Sharif University of Technology

Elsevier 2003

Abstract

It is known that discrete scale invariance leads to log-periodic corrections to scaling. We investigate the correlations of a system with discrete scale symmetry, discuss in detail possible extension of this symmetry such as translation and inversion, and find general forms for correlation functions. © 2003 Published by Elsevier Science B.V

3D Printing of PVDF Based Polymer Nanocomposites for Piezoelectric and Mechanical Properties

, M.Sc. Thesis Sharif University of Technology Ali Abed Al-Dulaimi, Hossein (Author) ; Pircheraghi, Gholamreza (Supervisor) ; Nemati, Ali (Supervisor)

Abstract

The research focused on developing polyvinylidene fluoride (PVDF) nanocomposites with enhanced piezoelectric and mechanical properties. To achieve this, barium titanate nanoplatelets (BTNPs) were incorporated at varying weight percentages into a PVDF matrix. Fused Deposition Modeling (FDM) 3D printing was employed to control nanoplatelets' orientation, aiming to improve properties. Initially, BTNPs were synthesized using the hydrothermal technique and homogeneously dispersed in a PVDF matrix with an internal mixer. Nanocomposite samples were fabricated using compression molding and analyzed with X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning...

A new approach to model sensitivity of graphene-based gas sensors

, Article Semiconductor Science and Technology ; Volume 30, Issue 4 , March , 2015 ; 02681242 (ISSN) Ghadiry, M ; Ismail, R ; Naraghi, B ; Taheri Abed, S ; Kavosi, D ; Fotovatikhah, F ; Sharif University of Technology

Institute of Physics Publishing 2015

Abstract

Carbon-based sensors are attractive because of their excellent sensing capability. In this paper, we propose a new approach to analytically model the sensitivity of these devices based on graphene. The model relies on the surface potential and current of the device. For the first time, we included ionization in the modelling and examined the importance of this effect. In order to validate the model, the results are compared with experimental data from a fabricated device