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    Warm Inflation Model in Effective Field Theory of Axion Monodromy

    , M.Sc. Thesis Sharif University of Technology Ghomi Shurkai, Reza (Author) ; Abolhassani, Aliakbar (Supervisor)
    Abstract
    Temerature fluctuation of the Cosmic Microwave Background (CMB) is one of the key observebles of the modern cosmology. Today, it is widely believed that quantum fluctuation that are stretched to horizon scales during a period of acceleration expansion -- at the onset of evolution of the universe-- are responsible for these perturbations. In the simplest scenarios of the inflation, a scalar field is responsible for both nearly expansional expansion of the universe and the proimordial fluctuations. In this thesis, we investigate the models of inflation with an additional light degree of freedom. In particular, we employ the method of the Effective Field Theory to study the general structure... 

    Determination of Loading and Unloading Program in a Cross-Docking System

    , M.Sc. Thesis Sharif University of Technology Mohammadi Ghomi, Sahar (Author) ; Akbari Jokar, Mohammad Reza (Supervisor)
    Abstract
    Using the cross docking is a strategy that plays inventory coordinating role in the supply chain. At the cross docking, products of inbound trucks are unloaded, sorted, moved and loaded onto outbound trucks for delivery to different destinations. In this concept, coordination between inbound and outbound trucks considering a cross-dock system with multiple receiving and shipping dock doors. Moreover, due to justifiability of all trucks to carry multiple product types, product assignment from inbound trucks to outbound trucks is determined simultaneous to scheduling. As an exact solution approach a MIP model is presented and since the problem is shown to be NP-hard, it can only be used to... 

    Persian End-To-End Speech Recognition

    , M.Sc. Thesis Sharif University of Technology Hajipour Ghomi, Farzaneh (Author) ; Sameti, Hossein (Supervisor)
    Abstract
    This thesis provids a Persian End-To-End Speech Recognition system. In this system, the input is low-level features of speech signal. Deep recurrent neural networks (RNNs) and Long Short-Term Memory (LSTM) units as the RNN building blocks are used as the acoustic model. Continuous speech data is labeled by the CTC which is applied as the output layer of a recurrent neural network. By using the CTC objective function, acoustic modeling problem is simplified to just an RNN learning problem over pairs of speech and context-independent (CI) label sequences. A distinctive feature of this system is a generalized decoding approach based on weighted finite-state transducers (WFSTs), which enables... 

    Mechanical strength improvement of mud motor’s elastomer by nano clay and prediction the working life via strain energy

    , Article International Journal of Engineering, Transactions B: Applications ; Volume 32, Issue 2 , 2019 , Pages 184-191 ; 1728144X (ISSN) Izadi, M ; Tabatabaee Ghomi, M ; Pircheraghi, G ; Sharif University of Technology
    Materials and Energy Research Center  2019
    Abstract
    In directional drilling, the most important thing that leads to pulling out the drill string is end of mud motor working life. Considering the working conditions of down hole mud motors; increasing the mechanical properties of their stator’s elastomer is crucial. Some attempts were done to increase the motor performance through geometrical changes but lack of material improvement is significant in previous studies. In this study, NBR/nanoclay composite samples were prepared through melt intercalation in an internal mixer and tested with regard to the temperature and drilling mud of down hole. Hardness, tear, fatigue and tensile test results of neat NBR elastomer and nanocomposite of NBR and... 

    Investigation of EGRET gamma-ray sources by an extensive air shower experiment

    , Article 29th International Cosmic Ray Conference, ICRC 2005, Pune, 3 August 2005 through 10 August 2005 ; Volume 6 , 2005 , Pages 29-32 Khakian Ghomi, M ; Samimi, J ; Bahmanabadi, M ; Sharif University of Technology
    Tata Institute of Fundamental Research  2005
    Abstract
    Ultra-high-energy ( E ≥ TeV) Extensive Air Showers (EASs) have been monitored for a period of five years (1997-2003 ), using a small array of scintillator detectors in Tehran, Iran. The data have been analyzed to take in to account of the dependence of source counts on zenith angle. During a calendar year different sources come in the field of view of the detector at varying zenith angles. Because of varying thickness of the overlaying atmosphere, the shower count rate is extremely dependent on zenith angle which have been carefully analyzed over time. High energy gamma-ray sources from the EGRET third catalogue where observed and the data were analyzed using an excess method. Upper limits... 

    Observation of EGRET gamma-ray sources by an extensive air shower experiment

    , Article Astronomy and Astrophysics ; Volume 434, Issue 2 , 2005 , Pages 459-467 ; 00046361 (ISSN) Khakian Ghomi, M ; Bahmanabadi, M ; Samimi, J ; Sharif University of Technology
    2005
    Abstract
    Ultra-high-energy (E > 100 TeV) Extensive Air Showers (EASs) have been monitored for a period of five years (1997-2003), using a small array of scintillator detectors in Tehran, Iran. The data have been analyzed taking into account the dependence of source counts on zenith angle. During a calendar year different sources come into the field of view of the detector at varying zenith angles. Because of varying thickness of the overlaying atmosphere, the shower count rate is extremely dependent on zenith angle, which has been carefully analyzed over time (Bahmanabadi et al. 2002, Exp. Astron., 13, 39). High energy gamma-ray sources from the EGRET third catalogue where observed and the data were... 

    Experimental studies of positive and negative atmospheric muons with a cosmic rays telescope

    , Article Astroparticle Physics ; Volume 24, Issue 3 , 2005 , Pages 183-190 ; 09276505 (ISSN) Bahmanabadi, M ; Khakian Ghomi, M ; Sheidaei, F ; Sharif University of Technology
    2005
    Abstract
    An experiment has been developed for the measurement of the muon charge ratio (ratio of positive to negative muons) in the cosmic ray flux in energy range 0.236-0.242 GeV. The muon charge ratio is found to be 1.35 ± 0.10 with a mean zenith angle of 32° ± 5°. Meanwhile, the distributions of muons in zenith (θ) and azimuth angles have been studied. A cosnθ distribution with n = 1.95 ± 0.13 has been obtained. An asymmetry has been observed in East-West directions because of geomagnetic field. © 2005 Elsevier B.V. All rights reserved  

    Loading of Drug and Nanostructured Coating on Dental Implant

    , M.Sc. Thesis Sharif University of Technology Abbaspour Ghomi, Somayya (Author) ; Sadrnezhaad, Khatiboleslam (Supervisor)
    Abstract
    The aim of this project is to load analgesic drug; Paracetamol on dental implant. The implant is titanium alloy (Ti-6Al-4V). There are two kinds of samples of anodized and HA coated onto anodized. They are in the shape of the sheets in this study. The electrodeposition and anodization carried out in order to treat the two samples. Nanotubes were formed during anodic oxidation of the samples in the 1M Ammonium sulfate (NH₄)₂SO4 and 5wt% Ammonium fluoride NH4F electrolyte. They are expected to play role of carrier for the model drug; paracetamol. The results showed that HA anodized Ti-6-4 has the ability to hold higher amounts of drug and also can keep the drug for a longer time than the... 

    Control a Double Inverted Pendulum Using Active Learning Method

    , M.Sc. Thesis Sharif University of Technology Ghomi Rostami, Mohammad (Author) ; Bagheri Shouraki, Saeid (Supervisor)
    Abstract
    There are lots of researches performed to investigate human being learning and try to model it. But, in case of huge complexity of its structure and function, almost none of so-far learning algorithms can model human learning process and, indeed, performance of human brain in real problems is much more than these algorithms. Moreover, in many cases, human is not aware or informed about internal structure or mathematical model of the present system he is working on; a child learning to walk has no information about his neuromuscular system and his brain slowly learns how to convey his little body by choosing the proper timing of muscle contractions. One of the accomplished researches in order... 

    A Blockchain Based System to Ensure Transparency and Originality in Supply Chain

    , M.Sc. Thesis Sharif University of Technology Ghomi Avili, Morteza (Author) ; Akhavan Niaki, Taghi (Supervisor)
    Abstract
    Emergence of crypto-currency and blockchain technology revolutionize supply chain processes. In addition, customer needs for more information on products or services from origin to destination, highlights the necessity of transparency, originality and traceability in supply chains. This research is aimed to develop a blockchain based system ascertaining supply chain transparency and originality. To this aim, a joint pricing and closed-loop supply chain network design problem is selected as a good platform to implement it. Due to increasing concerns on environmental issues and maximizing job opportunities, sustainability is also considered in the proposed problem. To ascertain transparency... 

    Galactic anisotropy of cosmic ray intensity observed by an air shower experiment

    , Article Publications of the Astronomical Society of Australia ; Volume 23, Issue 3 , 2006 , Pages 129-134 ; 13233580 (ISSN) Bahmanabadi, M ; Khakian Ghomi, M ; Sheidaei, F ; Samimi, J ; Sharif University of Technology
    2006
    Abstract
    We have monitored multi-TeV cosmic rays by a small air shower array in Tehran (35°43′ N, 51°20′ E, 1200 m ≤ 890 g cm -2). More than 1.1 × 106 extensive air shower events were recorded. These observations enabled us to analyse sidereal variation of the galactic cosmic ray intensity. The observed sidereal daily variation is compared to the expected variation which includes the Compton-Getting effect due to the motion of the earth in the Galaxy. In addition to the Compton-Getting effect, an anisotropy has been observed which is due to a unidirectional anisotropy of cosmic ray flow along the Galactic arms  

    The charge ratio of the atmospheric muons at low energy

    , Article Physical Review D - Particles, Fields, Gravitation and Cosmology ; Volume 74, Issue 8 , 2006 ; 15507998 (ISSN) Bahmanabadi, M ; Sheidaei, F ; Khakian Ghomi, M ; Samimi, J ; Sharif University of Technology
    2006
    Abstract
    From the nature of the muon production processes, it can be seen that the ratio of positive to negative cosmic muons has important information in both "the atmospheric neutrino problem," and "the hadronic interactions." We have carried out an experiment for the measurement of the muon charge ratio in the cosmic ray flux in momentum range 0.112-0.178GeV/c. The muon charge ratio is found to be 1.21±0.01 with a mean zenith angle of 32°±5°. From the measurements it has been obtained a zenithal angle distribution of muons as I(θ)=I(0)cos nθ with n=1.95±0.13. An asymmetry has been observed in East-West directions because of the geomagnetic field. Meanwhile, in about the same momentum range,... 

    A blockchain-based system for a network design problem considering pricing decisions and sustainability

    , Article Journal of Cleaner Production ; Volume 423 , 2023 ; 09596526 (ISSN) Ghomi Avili, M ; Akhavan Niaki, T ; Tavakkoli Moghaddam, R ; Sharif University of Technology
    Elsevier Ltd  2023
    Abstract
    The emergence of cryptocurrency and blockchain technology revolutionizes supply chains. In addition, blockchain technology can result in novel models ensuring supply chain transparency, originality, and traceability. This research is aimed to develop a blockchain-based system ascertaining supply chain transparency and originality. To this aim, a joint pricing and sustainable network design model is developed for a closed-loop supply chain. Labeling products with internet-of-thing (IoT) and radio frequency identification (RFID) technology strengthens originality and traceability in this supply chain. Afterward, smart contracts deal with transparency concerns while pricing the used products in... 

    Study of stochastic sequence-dependent flexible flow shop via developing a dispatching rule and a hybrid GA

    , Article Engineering Applications of Artificial Intelligence ; 2012 , Pages 494-506 ; 09521976 (ISSN) Kianfar, K ; Fatemi Ghomi, S. M. T ; Oroojlooy Jadid, A ; Sharif University of Technology
    2012
    Abstract
    A flexible flow shop is a generalized flow shop with multiple machines in some stages. This system is fairly common in flexible manufacturing and in process industry. In most practical environments, scheduling is an ongoing reactive process where the presence of real time information continually forces reconsideration of pre-established schedules. This paper studies a flexible flow shop system considering non-deterministic and dynamic arrival of jobs and also sequence dependent setup times. The problem objective is to determine a schedule that minimizes average tardiness of jobs. Since the problem class is NP-hard, a novel dispatching rule and hybrid genetic algorithm have been developed to... 

    Optimal constrained non-renewable resource allocation in PERT networks with discrete activity times

    , Article Scientia Iranica ; Volume 19, Issue 3 , 2012 , Pages 841-848 ; 10263098 (ISSN) Hashemin, S. S ; Fatemi Ghomi, S. M. T ; Modarres, M ; Sharif University of Technology
    2012
    Abstract
    In this paper, we develop an approach to optimally allocate a limited nonrenewable resource among the activities of a project, represented by a PERT-Type Network (PTN). The project needs to be completed within some specified due date. The objective is to maximize the probability of project completion on time. The duration of each activity is an arbitrary discrete random variable and also depends on the amount of consumable resource allocated to it. On the basis of the structure of networks, they are categorized as either reducible or irreducible. For each network structure, an analytical algorithm is presented. Through some examples, the algorithms are illustrated  

    A novel deterministic model for simultaneous weekly assignment and scheduling decision-making in operating theaters

    , Article Scientia Iranica ; Volume 24, Issue 4 , 2017 , Pages 2035-2049 ; 10263098 (ISSN) Haghi, M ; Fatemi Ghomi, S. M. T ; Hooshangi Tabrizi, P ; Sharif University of Technology
    2017
    Abstract
    This paper studies a simultaneous weekly assignment and scheduling decisionmaking problem in operating theaters with elective patients. Because of limited recourses in hospitals, considering assignment and scheduling decisions simultaneously can help mangers exploit the available resources more efficiently and make the work-load uniformly distributed during the planning horizon. This procedure can significantly reduce hospital costs and increase satisfaction of patients and personnel. This paper formulates the mentioned problem as a Mixed Integer Linear Program (MILP) considering applicable assumptions like finite recovery beds and limitation of equipment. Since the problem is NP-hard, in... 

    Control of a non observable double inverted pendulum using a novel active learning method based state estimator

    , Article Proceedings - UKSim 4th European Modelling Symposium on Computer Modelling and Simulation, EMS2010, 17 November 2010 through 19 November 2010 ; 2010 , Pages 21-26 ; 9780769543086 (ISBN) Ghatre Samani, A ; Bagheri Shouraki, S ; Eghbali, R ; Ghomi Rostami, M ; Sharif University of Technology
    2010
    Abstract
    In this paper a novel fuzzy approach exploiting Active Learning Method is employed in order to estimate the immeasurable states required to control a non-observable double inverted pendulum. Active Learning Method (ALM) is a fuzzy modeling method which exploits Ink Drop Spread (IDS) as its main engine. IDS is a universal fuzzy modeling technique which is very similar to the way human brain processes different phenomena. The ALM system is trained by the data obtained from Linear Quadratic Regulator (LQR) controller. LQR uses an optimal control approach which under certain conditions guarantees robustness. Instead of an expert's knowledge, the LQR controller output is used as a priori... 

    Simulation study on number of secondary particles in extensive air showers using CORSIKA code

    , Article Physical Review D - Particles, Fields, Gravitation and Cosmology ; Volume 77, Issue 8 , 2008 ; 15507998 (ISSN) Halataei, S. M. H ; Bahmanabadi, M ; Khakian Ghomi, M ; Samimi, J ; Sharif University of Technology
    2008
    Abstract
    We have simulated more than 105 extensive air showers (EAS) by CORSIKA code, with a proton as the primary particle. The range of energy for primary particles was selected from 50 TeV to 5 PeV, with differential flux given by dN/dE E-2.7. Using the secondary charged particles produced of these EASs, we obtained the function dNsp(θ,X)/dθ, where Nsp(θ,X) is the number of secondary charged particles in EASs as a function of atmosphere depth, X, and zenith angle, θ. A sin θcos n(X)θ distribution was obtained for zenith angle distribution of the number of secondary charged particles, where power index, n(X), is a function of atmosphere depth, X. We obtained n(X)=3.02+0.003Xln X-8.28×10-9X3-1.35ln... 

    A new method for finding core locations of extensive air showers

    , Article Astrophysical Journal ; Volume 727, Issue 2 , 2011 ; 0004637X (ISSN) Hedayati Kh., H ; Anvari, A ; Bahmanabadi, M ; Samimi, J ; Khakian Ghomi, M ; Sharif University of Technology
    Institute of Physics Publishing  2011
    Abstract
    Analysis of an extensive air shower (EAS) detected by surface arrays highly depends on the determination of core locations. Here we present a new method to find the core location of an EAS that, unlike the common methods, does not depend on the lateral distribution function and uses arrival times of secondary particles. This method improves the accuracy of finding the core location of a low-energy EAS in the internal parts of an array, in comparison with common methods  

    A new simple method for the analysis of extensive air showers

    , Article Astroparticle Physics ; Volume 34, Issue 9 , 2011 , Pages 699-704 ; 09276505 (ISSN) Hedayati Kh., H ; Anvari, A ; Bahmanabadi, M ; Samimi, J ; Khakian Ghomi, M ; Sharif University of Technology
    2011
    Abstract
    The most important goal of studying an extensive air shower is to find the energy, mass and arrival direction of its primary cosmic ray. In order to find these parameters, the core position and arrival direction of the shower should be determined. In this paper, a new method for finding core location has been introduced that utilizes trigger time information of particle detectors. We have also developed a simple technique to reconstruct the arrival direction. Our method is not based upon density-sensitive detectors which are sensitive to the number of crossing particles and is also independent of lateral distribution models. This model has been developed and examined by the analysis of...