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    Evaluation of Blockchain Technology in a Supply Chain with Multi-Criteria Decision Making (MCDM)

    , M.Sc. Thesis Sharif University of Technology Asghariyeh Ahari, Reza (Author) ; Haji, Alireza (Supervisor)
    Abstract
    Today, blockchain technology has attracted the attention of many traditional supply chains.The implementation of blockchain in the automotive industry supply chain can enhance data security, privacy, anonymity, traceability, accountability, integrity, robustness, transparency, reliability, and authentication. The number of blockchain platforms in the market is rapidly growing, but choosing the appropriate platform is a strategic and critical decision that requires the evaluation and selection of right criteria at first. Therefore, this research aims to assess blockchain technology in a supply chain using a multi-criteria decision-making approach. This study is a new approach to identify the... 

    A Reconfigurable Architecture Using Non-voltatile Memories

    , M.Sc. Thesis Sharif University of Technology Ahari, Ali (Author) ; Asadi, Hossein (Supervisor)
    Abstract
    In recent years, emerging Non-Volatile Memories (NVMs) have become promising alternatives for existing memory technologies. Due to shortcomings of SRAM memory in nanometer era,NVMs such as Phase-Change Memory (PCM) can be used in configuration memories of Field-Programmable Gate Arrays (FPGAs). Despite prominent features of emerging NVMs, they suffer from high write-power, high write-latency, and limited number of reliable write opera-tions. In addition, a dedicated Peripheral Circuit (PC) which is required to convert the NVM state to the equivalent voltage level can impose significant area and power overheads to FPGAs.In this thesis, a reliable power-efficient hybrid architecture employing... 

    A hybrid approach based on locally linear neuro-fuzzy modeling and TOPSIS to determine the quality grade of gas well-drilling projects

    , Article Journal of Petroleum Science and Engineering ; Vol. 114 , 2014 , pp. 99-106 ; ISSN: 09204105 Ahari, R. M ; Niaki, S.T. A ; Sharif University of Technology
    2014
    Abstract
    Evaluation of a project and its contractors has considerable importance in gas well-drilling projects due to their high investments and worth. In this paper, the quality of some gas well-drilling projects is analyzed in order to evaluate and grade project tasks. A neuro-fuzzy network is utilized to learn the grading process and generate models. To select among these models, a ranking method, namely technique for order of preference by similarity to ideal solution (TOPSIS) is employed. During seven gas well-drilling projects, 77 tasks are studied based on quality practitioners[U+05F3] points of view. After generating the primary models, three indices namely, root mean square error (RMSE),... 

    Solvability of 2-D Models of Statistical Mechanics and its Relation to Discretely Holomorphic Parafermions at Critical Points

    , M.Sc. Thesis Sharif University of Technology Tanhayi Ahari, Mostafa (Author) ; Rouhani, Shahin (Supervisor)
    Abstract
    Discretely holomorphic observables have recently been proposed for two dimensional lattice models at criticality, whose correlation functions satisfy a discrete version of Cauchy-Riemann relations. Existence of these observables appears to have a deep relation with integrability of the model. On the other hand at critical points of these models, there exist entities known as discrete parafermions whose Boltzmann weights satisfy the Yang-Baxter Equations. For this reason, finding parafermionic observables in any lattice model is equivalent to proof of solvability. This thesis is a step towards understanding the relation between Parafermions and Solvability. For instance, the Boltzmann weights... 

    Emerging non-volatile memory technologies for future low power reconfigurable systems

    , Article 9th International Symposium on Reconfigurable and Communication-Centric Systems-on-Chip, ReCoSoC ; 26-28 May , 2014 , pp. 1-2 ; 9781479958108 Ahari, A ; Asadi, H ; Tahoori, M. B ; Sharif University of Technology
    2014
    Abstract
    Non-volatile memory (NVM) technologies are promising alternatives to traditional CMOS memory technologies. While NVMs were primarily studied to be used in the memory hierarchy, they can also provide benefits in reconfigurable systems such as Field-Programmable Gate Arrays (FPGAs). In this paper, we investigate the applicability of different NVM technologies for the configuration bits of FPGAs and propose a power-efficient reconfigurable architecture based on Phase Change Memory (PCM). Quantitative analysis for various FPGA architectures using different memory technologies shows the benefits of the proposed scheme  

    A power-efficient reconfigurable architecture using PCM configuration technology

    , Article Proceedings -Design, Automation and Test in Europe, DATE ; 2014 Ahari, A ; Asadi, H ; Khaleghi, B ; Tahoori, M. B ; Sharif University of Technology
    2014
    Abstract
    Promising advantages offered by resistive NonVolatile Memories (NVMs) have brought great attention to replace existing volatile memory technologies. While NVMs were primarily studied to be used in the memory hierarchy, they can also provide benefits in Field-Programmable Gate Arrays (FPGAs). One major limitation of employing NVMs in FPGAs is significant power and area overheads imposed by the Peripheral Circuitry (PC) of NVM configuration bits. In this paper, we investigate the applicability of different NVM technologies for configuration bits of FPGAs and propose a power-efficient reconfigurable architecture based on Phase Change Memory (PCM). The proposed PCM-based architecture has been... 

    , M.Sc. Thesis Sharif University of Technology Mohammad Alippour Ahari, Roua (Author) ; Eshghi, Koorosh (Supervisor)
    Abstract
    The focus of this research is to present a model to verify the acceptance of projects with time and cost dependency on the usage of equipments. Decision on these projects is based on a dynamic programming in which at each stage, the profit of available projects in this stage, equipment value and the best choice of future stage are decision keys. In other words, after the completion of a project, it should be decided between doing a project or selling the equipment and leaving the remaining projects. For each projects, there is a product network that includes projects jobs and operations. After accepting projects, equipments of the projects will not be renewed and the usage of the equipments... 

    Radiation Effects on Geodesics in de Sitter Space: A Classical Approach

    , Article International Journal of Theoretical Physics ; Volume 51, Issue 6 , 2012 , Pages 1938-1945 ; 00207748 (ISSN) Fathi, M ; Tanhayi Ahari, M ; Tanhayi, M. R ; Tavakoli, F ; Sharif University of Technology
    2012
    Abstract
    In this work we first obtain a trajectory of a freely falling charged particle in de Sitter space and then in the classical approach, the effect of electromagnetic self-force on particle's trajectory has been considered. Finally, some limits for the problem have been presented  

    Multi-Objective Optimization in Cost, Time and Quality Trade-off in Projects with Quality Obtained by Locally Linear Neuro Fuzzy Networks Case Study: Well Drilling Projects

    , Ph.D. Dissertation Sharif University of Technology Mohammad Alipour Ahari, Roya (Author) ; Akhavan Niaki, Taghi (Supervisor)
    Abstract
    A common decision in project management is the selection of contractors to simultaneously optimize three objectives of the project’s triangle. This issue becomes more important if there is more monetary value involved or there is limited number of capable contractors. In project planning, there is numerous choices for tasks; each with specific time, cost and quality. There is no trade-off problem, if one of the choices has the best time, cost, and quality, simultaneously. However, as these criteria do not generally work in a unique direction, it makes the selection decision difficult. A contractor who performs the projects on time may have higher cost and lower quality. Given that there is a... 

    Towards dark silicon era in FPGAs using complementary hard logic design

    , Article Conference Digest - 24th International Conference on Field Programmable Logic and Applications, FPL 2014 ; Sept , 2014 , pp. 1 - 6 ; ISBN: 9783000446450 Ahari, A ; Khaleghi, B ; Ebrahimi, Z ; Asadi, H ; Tahoori, M. B ; Sharif University of Technology
    2014
    Abstract
    While the transistor density continues to grow exponentially in Field-Programmable Gate Arrays (FPGAs), the increased leakage current of CMOS transistors act as a power wall for the aggressive integration of transistors in a single die. One recently trend to alleviate the power wall in FPGAs is to turn off inactive regions of the silicon die, referred to as dark silicon. This paper presents a reconfigurable architecture to enable effective fine-grained power gating of unused Logic Blocks (LBs) in FPGAs. In the proposed architecture, the traditional soft logic is replaced with Mega Cells (MCs), each consists of a set of complementary Generic Reconfigurable Hard Logic (GRHL) and a conventional... 

    Vibrational Analysis of Carbon Nanoscroll tubes

    , M.Sc. Thesis Sharif University of Technology Jadid Ahari, Ali (Author) ; Ahmadian, Mohammad Taghi (Supervisor) ; Assempour, Ahmad (Supervisor)
    Abstract
    In recent year carbon nanostructures (CNS) has been the pinnacle of academic and industrial research. After development and refinement of better methods of controlled fabrication of high-quality CNS, these structures started substituting nanotubes in their renowned applications including nanochannels and nanocarriers. Due to the tunable core size of CNS using electric fields, they can be used as controlled ion channels and nanocarriers with controlled drug release as well as more dynamics oriented applications including nano-oscillators, nano-actuators and artificial muscle tissue. However lack of vibrational studies on CNS has hindered researchers in this path. In this thesis vibrational... 

    Spray characteristics and atomization behavior of bio-diesel (Norouzak) and diesel fuel blends

    , Article Particulate Science and Technology ; 2016 , Pages 1-12 ; 02726351 (ISSN) Ghahremani, A. R ; Jafari, M ; Ahari, M ; Saidi, M. H ; Hajinezhad, A ; Mozaffari, A. A ; Sharif University of Technology
    Taylor and Francis Inc  2016
    Abstract
    Norouzak oil seeds that are the source of bio-diesel (Norouzak) fuel grow mostly in Gonabad and Kashmar located in Khorasan, north east of Iran. Spray characteristics of Norouzak bio-diesel have been experimentally and theoretically studied in this work. Norouzak fuel is added to the conventional diesel fuel, and mixture formations of several blends have been investigated and compared with each other. Moreover, by varying ambient and injection conditions, behaviors of spray of different blends have been explored. Microscopic and macroscopic properties of spray such as Sauter Mean Diameter (SMD), Ohnesorge number, spray tip penetration, spray cone angle, spray projected area and volume have... 

    Spray characteristics and atomization behavior of bio-diesel (Norouzak) and diesel fuel blends

    , Article Particulate Science and Technology ; Volume 36, Issue 3 , 2018 , Pages 270-281 ; 02726351 (ISSN) Ghahremani, A. R ; Jafari, M ; Ahari, M ; Saidi, M. H ; Hajinezhad, A ; Mozaffari, A. A ; Sharif University of Technology
    Taylor and Francis Inc  2018
    Abstract
    Norouzak oil seeds that are the source of bio-diesel (Norouzak) fuel grow mostly in Gonabad and Kashmar located in Khorasan, north east of Iran. Spray characteristics of Norouzak bio-diesel have been experimentally and theoretically studied in this work. Norouzak fuel is added to the conventional diesel fuel, and mixture formations of several blends have been investigated and compared with each other. Moreover, by varying ambient and injection conditions, behaviors of spray of different blends have been explored. Microscopic and macroscopic properties of spray such as Sauter Mean Diameter (SMD), Ohnesorge number, spray tip penetration, spray cone angle, spray projected area and volume have... 

    Experimental and theoretical investigations on spray characteristics of bio-ethanol blends using a direct injection system

    , Article Scientia Iranica ; Volume 24, Issue 1 , 2017 , Pages 237-248 ; 10263098 (ISSN) Ghahremani, A. R ; Jafari, M ; Ahari, M ; Saidi, M. H ; Hajinezhad, A ; Mozafari, A. A ; Sharif University of Technology
    Sharif University of Technology  2017
    Abstract
    In the present work, the spray characteristics of bio-ethanol and its blends have been experimentally and theoretically investigated. To have a comprehensive study, the effects of ambient condition and injection pressure on the spray of different blends have been considered. Macroscopic and microscopic characteristics of spray such as tip penetration length, cone angle, projected area, volume, Sauter Mean Diameter (SMD), and Ohnesorge number are investigated precisely. Besides, air entrainment and atomization analyses have been carried out to improve mixture formation process. Using curve fitting and least squares method, theoretical correlations have been suggested in such a way to predict... 

    A misbehavior‐tolerant multipath routing protocol for wireless Ad hoc networks [electronic resource]

    , Article International Journal of Research in Wireless Systems (IJRWS) ; Vol. 2, Issue 9, pp. , Sep. 2013 Sedghi, H. (Haniyeh) ; Pakravan, Mohammad Reza ; Aref, Mohammad Reza ; Sharif University of Technology
    Abstract
    Secure routing is a major key to service maintenance in ad hoc networks. Ad hoc nature exposes the network to several types of node misbehavior or attacks. As a result of the resource limitations in such networks nodes may have a tendency to behave selfishly. Selfish behavior can have drastic impacts on network performance. We have proposed a Misbehavior-Tolerant Multipath Routing protocol (MTMR) which detects and punishes all types of misbehavior such as selfish behavior, wormhole, sinkhole and grey-hole attacks. The protocol utilizes a proactive approach to enforce cooperation. In addition, it uses a novel data redirection method to mitigate the impact of node misbehavior on network... 

    Analysis and data-based reconstruction of complex nonlinear dynamical systems : using the methods of stochastic processes

    , Book Rahimi Tabar, M. Reza
    Springer International Publishing  2019
    Abstract
    This book focuses on a central question in the field of complex systems: Given a fluctuating (in time or space), uni- or multi-variant sequentially measured set of experimental data (even noisy data), how should one analyse non-parametrically the data, assess underlying trends, uncover characteristics of the fluctuations (including diffusion and jump contributions), and construct a stochastic evolution equation?
    Here, the term "non-parametrically" exemplifies that all the functions and parameters of the constructed stochastic evolution equation can be determined directly from the measured data.
    The book provides an overview of methods that have been developed for the analysis of... 

    Fabrication and Study of Mechanical Behavior of in Situ Microfibrillar- Reinforced Composites of Polypropylene/Recycled Poly (Ethylene Terephthalate)Toughened with Rubber Particles

    , M.Sc. Thesis Sharif University of Technology Motahari, Tayebeh (Author) ; Bagheri, Reza (Supervisor) ; Alizadeh, Reza (Supervisor)
    Abstract
    The use of polymers is increasing day by day due to low density, reasonable price and ability to produce different products. On the other hand, the accumulation of polymer wastes in nature is one of the environmental concerns in today's world, which is mainly due to the widespread use of polymers in the packaging industry and disposable applications. In order to solve this problem, recycling is recommended as the most appropriate and economical solution. Because in addition to consuming polymer waste, it also saves energy and reduces carbon footprint.Polyethylene terephthalate (PET) is one of the polymeric materials which; It has a special place in the packaging industry and is widely used... 

    Characterization of Mechanical Properties of Polymer Nanocomposites with Spherical Inhomogeneities

    , M.Sc. Thesis Sharif University of Technology Goudarzi, Taha (Author) ; Naghdabadi, Reza (Supervisor) ; Bagheri, Reza (Supervisor)
    Abstract
    The improved properties of nanocomposites are not achievable with conventional composites. Scale effect is one the most important parameters in the physical and mechanical properties of polymeric nanocomposites. One of the physical phenomena, which can be related to the scale effect, is the very large interface between the nanoparticles and the polymeric matrices. Motional behavior and conformation of polymeric chains change near the nanoparticles surfaces. Due to high interface of the nanoparticles with the polymeric matrices the amount of these types of changes in the polymeric chains are so large that can change the physical and mechanical properties of polymeric nanocomposites. In this... 

    On small uniquely vertex-colourable graphs and Xu's conjecture [electronic resource]

    , Article Discrete Mathematics ; Volume 223, Issues 1–3, 28 August 2000, Pages 93–108 Daneshgar, A. (Amir) ; Naserasr, Reza ; Sharif University of Technology
    Abstract
    Consider the parameter Λ(G) = |E(G)| - |V(G)|(k - 1) + (k2) for a k-chromatic graph G, on the set of vertices V(G) and with the set of edges E(G). It is known that Λ(G)≥0 for any k-chromatic uniquely vertex-colourable graph G (k-UCG), and, S.J. Xu has conjectured that for any k-UCG, G, Λ(G) = 0 implies that cl(G) = k; in which cl(G) is the clique number of G. In this paper, first, we introduce the concept of the core of a k-UCG as an induced subgraph without any colour-class of size one, and without any vertex of degree k - 1. Considering (k, n)-cores as k-UCGs on n vertices, we show that edge-minimal (k, 2k)-cores do not exist when k ≥ 3, which shows that for any edge-minimal k-UCG on 2k... 

    Molecular Dynamics Simulation of Nano-Diamond Synthesis by Shock Wave

    , Ph.D. Dissertation Sharif University of Technology Mahnama, Maryam (Author) ; Naghdabadi, Reza (Supervisor) ; Movahhedy, Mohammad Reza (Co-Advisor)
    Abstract
    In the field of high-pressure material science, diverse carbon systems under pressure have been intensively studied with interest in synthesizing new phases. A variety of these synthetic phases which have met various applications in today technology are called the amorphous diamond. The pressure-induced structural transition of carbonaceous material to amorphous diamond is realized by shock compression and rapid quenching. The shock compression and rapid quenching generate the high pressure (several GPa) and the temperature (several hundred K) in a fraction of a microsecond.Since the mechanical and electrical properties of the synthetic diamond are severely sensitive to the atomic structure,...