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    A Study on Readiness for Change in Project-Based Organizations that are Establishing a Project Management Office (PMO)

    , M.Sc. Thesis Sharif University of Technology Tabatabei Lotfi, Mir Hossein (Author) ; Mashayekhi, Ali Naghi (Supervisor) ; Alavi, Babak (Supervisor)
    Abstract
    A great rise in the number of projects undertaken simultaneously within organizations and consequently, a further increase in the complexity of managing them, has led to emerging innovative forms of organizational structures. There are new concepts developing in project management literature such as program management, portfolio management and project management offices (PMOs). PMOs have recently been used as a means for managing large projects, based on the need for an overall, coherent approach. Project offices are established to coordinate portfolios of projects and achieve project management oversight, control and support. Based on the structure and definition proposed by Hill (2004), it... 

    Design of Traffic Generator for Security Evaluation of Industrial Network

    , M.Sc. Thesis Sharif University of Technology Lotfi Foroushani, Masoud (Author) ; Jahangir, Amir Hossein (Supervisor)
    Abstract
    Today's modern industrial control systems (ICS) and SCADA infrastructures, use industrial networks to communicate with the sensors and actuators installed in the field. In recent years the increase in use of standard protocols in this networks, and also the connection of industrial networks to the internet introduced new challenges in the area of industrial network security. The difference in the property, size, and requirements of this networks in comparison to legacy computer networks have made the legacy security solutions such as firewalls and IDS to not have enough efficiency. Some researches work on implementing new solution to meet the requirements of industrial networks in the area... 

    Forecasting P/E Ratio by Decomposing into Constituent Factros

    , M.Sc. Thesis Sharif University of Technology Lotfi, Ali (Author) ; Zamani, Shiva (Supervisor) ; Abdoh Tabrizi, Hossein (Supervisor)
    Abstract
    P/E ratio is studied in four levels in this study:
    1)Macroeconomics level
    2)Capital market level
    3)Industry level
    4)Company level
    The first level studies effects of macroeconomics variables on P/E ratio. At this level we use variables such as economic growth, inflation, exchange rate, and etc.The next level uses capital market variables such as market volume, and IPO information.The third level that we study in this research is industry level. Stocks of an industry generally behave similar, because they have common advantages and disadvantages, thus industry is an effective factor on P/E ratio.The last level studies financial statements and internal features of a... 

    Value Creation in Content-oriented E-business

    , M.Sc. Thesis Sharif University of Technology Lotfi, Ali (Author) ; Miremadi, Iman (Supervisor) ; Ghafoori, Mohammad Hossein (Co-Supervisor)
    Abstract
    Considering the high growth potential of creative industry as well as the increasing trend of e-business, content-oriented digital business has been the main focus of this research. These enterprises are a subset of the creative industry that are primarily developed in the digital context. After reviewing the literature, it was observed that the keyword "value creation" in this type of business has been less considered by research.On the other hand, in conversations with managers who are active in the industry, a practical vacuum was revealed on how to create value in these firms; Because a comprehensive review of value creation processes in these firms can ultimately lead to more profitable... 

    Applications of Statistical Learning in Dynamic Pricing

    , M.Sc. Thesis Sharif University of Technology Torkashvand, Sina (Author) ; Haji Mir Sadeghi, Mir Omid (Supervisor)
    Abstract
    In the era of the internet and with the emergence of online stores, the possibility of changing prices for these e-commerce platforms has become simple and virtually cost-free. This allows them to adjust prices optimally in response to environmental and surrounding factors, maximizing their revenue from product sales. This development has led to numerous applications of statistical learning methods, particularly online learning, in these markets. In this thesis, we explore the issue of online pricing from various perspectives. One aspect is that product pricing is based on their features, which can be numerous. This leads us to the use of online learning methods and statistical learning in... 

    Experimental and Numerical Study of Multi-track Laser Cladding to Evaluate Effects of Residual Stress on Fatigue Life

    , Ph.D. Dissertation Sharif University of Technology Ghorashi, Mir Siavash (Author) ; Movahhedy, Mohammad Reza (Supervisor) ; Farrahi, Gholam Hossein (Supervisor) ; Shodja Razavi, Reza (Co-Supervisor)
    Abstract
    Laser cladding is a processing technique of layer-by-layer material deposition which is widely used to repair important components. However, tensile residual stresses generated in this process may result in detrimental effects such as crack, undesirable deformation and reduced fatigue life. A thermo-mechanical finite element model is developed to accurately predict residual stresses of the multiple beads laser cladding process with incorporating the cyclic plasticity into the analysis by utilizing the nonlinear kinematic hardening behavior. FE results are presented for Inconel 718, a material for which the laser cladding process is widely used. The FE results are compared with those of... 

    Control of Chaotic Waves in Hard Disk Drives

    , M.Sc. Thesis Sharif University of Technology Rajabi, Majid (Author) ; Jalali, Mir Abbas (Supervisor)
    Abstract
    Hard disk drives are the main component of computers for permanent data storage. The security of the stored data is related closely to the air gap between the read-write head and the surface of disk. This gap which is created by the aerodynamic force between head and the disk is altered continually by lateral oscillations of disk. In the extreme condition of zero gap and contact between the protective coating layer and subsequently the magnetic material of the disk with the head, the disk will be scratched and damaged. Therefore, the active or passive control of these vibrations has a particular importance in the technology of manufacturing of hard disks. The first step in active control... 

    The Motility of Lipid Vesicles Due to Phase Transition in Transmemerance Proteine

    , M.Sc. Thesis Sharif University of Technology Heidari, Maziar (Author) ; Jalali, Mir Abbas (Supervisor)
    Abstract
    Phospholipid vesicles are able to carry drugs or DNA to infected or cancerous cells. The blood flow can carry them to their target positions but their performance will be enhanced if they complete their attack by swimming in final stages of their journey. Vesicles built only by lipid molecules have rotational symmetry and undergo a random motion in their solvents without having a preferred direction. In this project, we break the symmetrical shape of phospholipid vesicles by a cluster of transmembrane proteins. We use a triangulated model of the membrane, apply the method of multi-particle collision dynamics to the motion of solvent particles, and simulate the motility of vesicles for... 

    A Study of the Phase Diagram of the Hubbard Model Using Modern Numerical Methods

    , M.Sc. Thesis Sharif University of Technology Manavi, Alireza (Author) ; Vaezi, Mir Abolhassan (Supervisor)
    Abstract
    The Hubbard model is one of the simplest interacting models in theoretical physics, especially condensed matter physics which despite its simplicity, its solutions are highly nontrivial and intractable. After 5 decades since its introduction, its phase diagram is not fully understood and whether or not, it has a high-temperature superconducting phase. In this thesis, we aim to employ the recent advances in machine learning and GPU programming to accelerate the QMC method. By accelerated QMC methods, we can explore the Hubbard model's phase diagram more efficiently. Using massive parallelization of the GPUs can speed up the measuring process by several times. The self-learning quantum... 

    A hybrid scaffold of gelatin glycosaminoglycan matrix and fibrin as a carrier of human corneal fibroblast cells

    , Article Materials Science and Engineering C ; Volume 118 , 2021 ; 09284931 (ISSN) Hajian Foroushani, Z ; Mahdavi salimi, S ; Abdekhodaie, M. J ; Baradaran Rafii, A ; Tabatabei, M. R ; Mehrvar, M ; Sharif University of Technology
    Elsevier Ltd  2021
    Abstract
    A hybrid scaffold of gelatin-glycosaminoglycan matrix and fibrin (FGG) has been synthesized to improve the mechanical properties, degradation time and cell response of fibrin-like scaffolds. The FGG scaffold was fabricated by optimizing some properties of fibrin-only gel and gelatin-glycosaminoglycan (GG) scaffolds. Mechanical analysis of optimized fibrin-only gel showed the Young module and tensile strength of up to 72 and 121 KPa, respectively. Significantly, the nine-fold increase in the Young modulus and a seven-fold increase in tensile strength was observed when fibrin reinforced with GG scaffold. Additionally, the results demonstrated that the degradation time of fibrin was enhanced... 

    Evaluating the Leanness and Agility Indexes of S.G.S Co

    , M.Sc. Thesis Sharif University of Technology Lotfi, Maryam (Author) ; Houshmand, Mahmoud (Supervisor)
    Abstract
    In this research ,lean and agile indexes in S.G.S Co. are evaluated. This company is the first company in engineering and supplying automotive parts as well as the first supply chain management and organization of Saipa Group. In the part of evaluating the lean management level it is the developed model of the suggested approach by Jackson “implementing a lean management system” (Jackson, 1996). As S.G.S is engaged in servicing activities not in production, we have changed some factors in Jackson's methodology. Different with the last model, we got the results and used AHP method for getting the level in each key. Finally by using another AHP the lean index of the S.G.S Co. was identified.... 

    Design and Optimization of a Subsonic Wind Tunnel Profile with Two Test Sections using CFD

    , M.Sc. Thesis Sharif University of Technology Lotfi, Iman (Author) ; Darbandi, Masoud (Supervisor)
    Abstract
    In this project, we are willing to analyze and design a subsonic wind tunnel WT configuration for the Aerospace Engineering Department in Sharif University of Technology. This WT will be an open-circuit "suck down" type, whose entry is open to the atmosphere (laboratory) and three axial fans downstream of its test section. In addition to three parallel fans, we are expected to design two simultaneous small and large size test sections for it. The small and large sections would have an area about 1.4 and 4 m2and maintain a maximum air velocity of 100 and 50 m/s, respectively. So, our design is faced with two main complexities. In one hand, we are to manage the air flow through these two test... 

    Effect of metal doping, boron substitution and functional groups on hydrogen adsorption of MOF-5: A DFT-D study

    , Article Computational and Theoretical Chemistry ; Vol. 1044, issue , 2014 , Pages 36-43 ; ISSN: 2210271X Lotfi, R ; Saboohi, Y ; Sharif University of Technology
    2014
    Abstract
    In the present work, adsorption of hydrogen molecules over a metal organic framework (MOF-5) has been investigated by using first principles density functional theory (DFT). Different strategies have been applied for improving hydrogen storage, i.e. metal doping, boron substitution and functionalization. The metal atoms used for enhancing hydrogen adsorption include Li, Ca and Sc. It is found that the binding energy between these metal atoms and MOF is not enough to prevent clustering. Therefore a number of carbon atoms are substituted by boron atoms and it is indicated that boron substitution enhances the binding energies, significantly. Also the results reveal that boron substituted MOF... 

    Interaction of hydrogen molecules with perfect, defective and scandium doped polycyclic aromatic hydrocarbon structures

    , Article Computational and Theoretical Chemistry ; Volume 1026 , 2013 , Pages 65-71 ; ISSN: 2210271X Lotfi, R ; Saboohi, Y ; Sharif University of Technology
    2013
    Abstract
    In the present work the interaction of hydrogen molecules with perfect, defective and scandium doped polycyclic aromatic hydrocarbon (PAH) has been evaluated. At first the potential barrier for the penetration of hydrogen molecules through PAH structures has been investigated and then the adsorption of hydrogen molecules over PAH structures has been studied. To model the graphene surface for barrier calculations, it is shown that coronene can successfully estimate the graphene monolayer. The barrier height is calculated for perfect and two different defective PAH structures including Stone-Wales (SW) and 585. It is found that PAH even with small defects is impermeable to hydrogen molecules.... 

    A comparative study on hydrogen interaction with defective graphene structures doped by transition metals

    , Article Physica E: Low-Dimensional Systems and Nanostructures ; Vol. 60 , June , 2014 , pp. 104-111 ; ISSN: 13869477 Lotfi, R ; Saboohi, Y ; Sharif University of Technology
    2014
    Abstract
    In the present work, the interaction of hydrogen molecules with defective graphene structures doped by transition metal (TM) atoms is investigated by using first principles density functional theory (DFT). Defective graphene structures include Stone-Wales (SW), 585 and 555-777 and transition metals include early TMs, i.e. scandium (Sc), titanium (Ti) and vanadium (V). It is found that in comparison with the pristine graphene, presence of defects significantly enhances the metal binding. Among three defects, 585 divacancy leads to the strongest binding between graphene and metal. Hydrogen adsorption is then evaluated by sequential addition of hydrogen molecules to the system. The results... 

    Interaction of hydrogen molecules with defective graphene sheets: An ab initio study

    , Article AIChE 2012 - 2012 AIChE Annual Meeting, Conference Proceedings ; 2012 ; 9780816910731 (ISBN) Lotfi, R ; Saboohi, Y ; Sharif University of Technology
    2012
    Abstract
    Hydrogen appears as one of the most promising energy carriers. Hydrogen has the advantage of being the cleanest fuel and as a result it can efficiently help limiting the greenhouse effect. However one of the major barriers for the large scale use of hydrogen, especially in the transportation sector, is hydrogen storage issue. There are four different technologies for storing hydrogen which are as follows: (1) Cryogenic liquid hydrogen (LH); (2) compressed gas storage; (3) metal hydride storage technology; (4) Physisorption methods. Physisorption of hydrogen in novel carbon nanostructures such as carbon nanotubes and graphene seems to be a safe and promising method for storage of hydrogen.... 

    Design of Power Amplifier in 6-18GHz Frequency Band with Employment and Evaluation Reliability Improvement Methods

    , M.Sc. Thesis Sharif University of Technology Lotfi, Hadi (Author) ; Medi, Ali (Supervisor)
    Abstract
    Today usage of microwave integrated circuits in commercial and military applications is very common, especially with emerging of monolithic microwave integrated circuits that make mass production with good quality and price possible. A lot of attention are paid to designing power amplifiers used in the end of transmitter line. Because of power dispersion in transistor channels, high power amplifier causes excessive heat on the chip. Channel temperature increasing, causes operation retrogradation in circuits that result in destruction of the chip. So it is necessary to transfer this heat to the outside from the chip. It is usual to use a heatsink for this problem, however for low thermal... 

    Drag performance of divergent tubular-truncated cones: A shape optimization study

    , Article International Journal of Environmental Science and Technology ; Volume 9, Issue 1 , 2012 , Pages 105-112 ; 17351472 (ISSN) Lotfi, A ; Rad, M ; Sharif University of Technology
    2012
    Abstract
    The use of more efficient energy consuming devices, which are closely associated with reduction of environmental pollution, has gained significant interest in the recent decades. The reduction of drag coefficient also improves safety and durability of environmental structures subjected to high-velocity fluid flow, and causes the noise and vibration to decrease as well. This paper describes the efficiency improvement in energy management by means of reducing drag coefficient in a practical divergent tubular- truncated cone. Extensive numerical simulations with emphasis on the shape optimization study were performed in order to find minimum drag coefficient for both laminar and turbulent flows... 

    Global adaptive estimation of joint velocities in robotic manipulators

    , Article IET Control Theory and Applications ; Volume 4, Issue 12 , December , 2010 , Pages 2672-2681 ; 17518644 (ISSN) Lotfi, N ; Namvar, M ; Sharif University of Technology
    2010
    Abstract
    This study presents a method for global estimation of joint velocities in robotic manipulators. The authors consider a non-minimal model of a robotic manipulator and design an adaptive observer capable of handling uncertainties in robot dynamics. Smoothness of the dynamics of the proposed observer allows its easy implementation in comparison with non-smooth observers. Dimension of the proposed observer is shown to be at least 3n where n stands for the manipulator's degrees of freedom. This number is less than the dimension of most existing globally convergent adaptive observers. Global asymptotic convergence of state estimates to their true values is achieved under no persistency of... 

    Design, analysis and implementation of class-E ZCS/ZCDS power amplifier for any duty ratio with nonlinear output parasitic capacitance

    , Article Analog Integrated Circuits and Signal Processing ; Volume 89, Issue 1 , 2016 , Pages 185-195 ; 09251030 (ISSN) Lotfi, A ; Medi, A ; Sharif University of Technology
    Springer New York LLC  2016
    Abstract
    This paper gives the design and analysis approaches for the class-E power amplifier with a shunt inductor under the nominal conditions, i.e., zero-current switching (ZCS) and zero-current derivative switching (ZCDS), with taking into account the MOSFET nonlinear output parasitic capacitance at any duty ratio. Although, the class-E ZCS/ZCDS conditions obtained high-efficiency, but the switch-current waveform affected by the slope of the voltage across the MOSFET nonlinear drain-to-source parasitic capacitance during the switch-off state, which restricted the operating frequency. On the other hand, the duty ratio is an adjustment parameter to obtain high-frequency operation. Therefore, the...