Loading...
Search for: seyf--hamed
0.126 seconds

    Modeling of the Flood-induced Failure of Community Infrastructure Systems with Emphasis on Food Supply Chain

    , M.Sc. Thesis Sharif University of Technology Daneshifar, Asma (Author) ; Kashani, Hamed (Supervisor)
    Abstract
    This study provides a probabilistic framework for assessing and quantifying flood damage to infrastructure. This framework models the state of the community's infrastructure after the occurrence of possible floods in five steps. The first step is to model the hazard using a set of models that determine the characteristics of potential floods. The second step is to model and estimate the damage to community buildings and infrastructure. In the third step, infrastructure serviceability is modeled. The infrastructures that are modeled in this study are water distribution network, power network, transportation networks and industrial facilities for processing agricultural products. In the fourth... 

    Active Control of Edgewise Vibrations in Wind Turbine Blade by Optimization of the Number and Locations of the Intermediate Actuators

    , M.Sc. Thesis Sharif University of Technology Pishbahar, Baher (Author) ; Moradi, Hamed (Supervisor)
    Abstract
    Vibrations in HAWT reduce their efficiency and increase maintenance costs. In this paper, the blade edgewise vibrations are reduced by using several actuators in different parts of the wind turbine blade and optimization of the number and locations of actuators. The wind turbine blade dynamic behavior is investigated by using dynamic modeling. The actuators are trusses that are located inside each blade and apply control force to different parts of the blade. Active control force is applied to reduce edgewise vibrations. The designed controller is applied and simulated on NREL 5MW wind turbine. By applying the controller, the edgewise vibrations of wind turbine blades are significantly... 

    Probabilistic Modeling of the Repair Time and Cost of the Structural Components of Earthquake-damaged Buildings

    , M.Sc. Thesis Sharif University of Technology Emamgholi, Ali (Author) ; Kashani, Hamed (Supervisor)
    Abstract
    This study aims to investigate the cost and time uncertainty of the seismic repair process of structural elements in earthquake damaged buildings in Iran. In order to identify the most important type of structural system in the country, using the method of analytic hierarchy process (AHP), 39 activists in the field of construction were interviewed. Based on the results, in buildings with reinforced concrete materials, concrete moment frames and in buildings with steel materials, steel moment frames and braced steel braced frames are the most important structural systems. By selecting the structural component of lateral load-bearing in each of the mentioned structural systems and considering... 

    Robust Controller Design for Three-Dimensional Overhead Crane System with Variable Cable Length

    , M.Sc. Thesis Sharif University of Technology Khoshnazar, Mohammad (Author) ; Moradi, Hamed (Supervisor)
    Abstract
    The main goal of controlling overhead crane systems is to safely transfer the load to its desired position with maximum speed and accuracy, as well as to minimize or eliminate load oscillations. The overhead crane system is considered as an underactuated mechanical system in which the number of control inputs (actuators) is less than the number of degrees of freedom. In addition, overhead crane systems are generally associated with parametric or unmodeled uncertainties. Also, in these systems, external disturbances such as wind have a destructive effect on the system's performance. In addition, if the overhead crane has the hoisting mechanism and the length of the rope changes as the trolley... 

    Study of Enzyme (Chymotrypsin) -Core/Shell (Fe3O4 @ Au) Nanoparticle Bioconjugate

    , M.Sc. Thesis Sharif University of Technology Kamal Ahmadi, Mahmoud (Author) ; Vosoughi, Manoochehr (Supervisor) ; Seyf Kordi, Ali Akbar (Supervisor)
    Abstract
    Conjugation of proteins to nanoparticles has numerous applications in sensing, imaging, delivery, catalysis, therapy and control of protein structure and activity. Therefore, characterizing the nanoparticle–protein interface is of great importance. A variety of covalent and non-covalent linking chemistries have been reported for nanoparticle attachment. Typically, a specific protein residue is linked directly to the nanoparticle core or to the ligand. As conjugation often affects the protein structure and function, techniques to probe structure and activity are assessed Characterization studies of nanoparticle–protein complexes show that the structure and function are influenced by the... 

    Hot workability of ultrafine-grained aluminum alloy produced by severe plastic deformation of Al6063 powder and consolidation [electronic resource]

    , Article Materials Science Forum ; Volume 667-669, 2011, Pages 979-984 Asgharzadeh, H. (Hamed) ; Simchi, A. (Abdolreza) ; Seop Kim, Hyoung ; Sharif University of Technology
    Abstract
    Al6063 powder was subjected to severe plastic deformation via high-energy mechanical milling to prepare ultrafine-grained (UFG) aluminium alloy. Uniaxial compression test at various temperatures between 300 and 450 °C and strain rates between 0.01 and 1 s-1 was carried out to evaluate hot workability of the material. Microstructural studies were performed by EBSD and TEM. The average activation energy and strain rate sensitivity of the hot deformation process were determined to be 280 kJ mol-1 and 0.05, respectively. The deformation temperature and applied strain rate significantly affected the grain structure of UFG Al alloy. A finer grain structure was obtained at lower temperatures and... 

    Evaluation of Dea Models for the Out puts,Inputs Estimation and Improvement Organizational Performance

    , M.Sc. Thesis Sharif University of Technology Hamed Ranjkesh, Somayyeh (Author) ; Kianfar, Farhad (Supervisor)
    Abstract
    Measurement of efficiency is a significant issue in organizations which is used to improvement efficiency and performance .one of the serious offaires in any country, is banking, inefficiency in which leads to problems and obstacles in developing capital market. In this research, Data Envelopment Analysis models are used to estimate the extent of performance in decision making units (DMU’s) to improve inefficient ones. We change the inputs ( outputs) to a special unit at both the constancy or improvement of efficiency using the DEA models, we estimate the values of output ( input ) levels. Howeve, we assume the data of (the values of input ( output ) levels ) can be either crisp or interval.... 

    Design of Continuous and Time-Invariant Controllers for Exponential Stabilization of Periodic Walking and Running Locomotion in Planar Bipedal Robots

    , Ph.D. Dissertation Sharif University of Technology Akbari Hamed, Kaveh (Author) ; Sadati, Nasser (Supervisor)
    Abstract
    During the last decades there have been enormous advances in robot control of dynamic walking and running. The desire to study legged locomotion has been motivated by 1) the desire to replace humans in hazardous occupations, 2) the desire to assist disabled people to walk and 3) the desire to investigate the complicated motions of the mankind. The control of dynamic walking and running is complicated by (i) limb coordination, (ii) hybrid nature of running due to presence of impact and takeoff, (iii) underactuation and overactuation, (iv) inability to apply the Zero Moment Point (ZMP) criterion, (v) lack of algorithms to achieve feasible period-one orbits, and (vi) conservation of angular... 

    A Framework to Forecast Highway Construction Materials Prices

    , M.Sc. Thesis Sharif University of Technology Faghih, Amir Mohsen (Author) ; Kashani, Hamed (Supervisor)
    Abstract
    Due¬ to the volatile nature of material prices, projecting highway construction costs are proven to be very difficult, leading to many challenges in cost estimation process. Bid preparations as well as project planning and control processes are also negatively affected by the concerns about the inaccuracy of cost projections. There is a growing body of evidence that suggests the use of inaccurate cost estimate can result in bid loss or profit loss for contractors and hidden price contingencies, delayed or cancelled projects, inconsistency in budgets and unsteady flow of projects for owner organizations. Analysis of historical data indicates that a relationship between construction materials... 

    A fast and reliable multi-sender algorithm for peer-to-peer networks

    , Article Journal of Network and Computer Applications ; Volume 32, Issue 3 , May , 2009 , Pages 733–740 Firooz, M. H. (Mohammad Hamed) ; Sharif University of Technology
    2009
    Abstract
    Due to special constraints in peer-to-peer (P2P) networks (such as bandwidth limitation) and because of their highly dynamic characteristics, a single node cannot provide a reliable multimedia stream to the receivers. Several multi-sender algorithms are proposed to reliably deliver a media stream to the receiver through the intrinsically unreliable P2P networks. Based on upload bandwidths and availability of peers as well as the bandwidths of the links connecting the senders and the receiver, PROMISE selects a set of active senders to maximize the expected bit-rate delivered to the receiver. By careful investigation of PROMISE, in this paper, we present why and how it deviates from finding... 

    Design, Modeling and Investigation of Seismic Behavior of Bracing Type Steel Shear Panels

    , Ph.D. Dissertation Sharif University of Technology Akbari Hamed, Arash (Author) ; Mofid, Massoud (Supervisor)
    Abstract
    So far a number of solutions have been proposed to resolve some problems of steel plate shear walls including large induced loads on the surrounding members, late panel’s yielding along with lack of openings. One of the forms that can be considered for steel shear walls is braced shear panels.Regarding to the many advantages of this structural system, in this thesis steel shear panels with concentric or eccentric bracing have been introduced. For this purpose, first a procedure for plastic analysis and design, aiming to develop a predetermined collapse mechanism, is proposed. The results demonstrate that the closed-form analytical equations along with the extension of failure mode control... 

    Evaluation of Hollowfiber Membranes Uesd In Hemodialysis

    , M.Sc. Thesis Sharif University of Technology Hamed, Hamid (Author) ; Abdekhodaei, Mohammad Jafar (Supervisor)
    Abstract
    Due to largre number of patients treated by dialysis and its significant increasing progress, dialysis efficiency and patients' life quality are of great interest.Dialyzer, the dialysis beating heart, has the role of cleaning blood by removing toxic solutes and balancing volume of bood's water through hollow fiber membranes. In this thesis, firstly we tried to focus on performance characteristics of dialyzer by studying effective parameters influencing dialyzer efficiency and ultimately we set two important performance characteristics, ultrafiltration coefficient and solute clearance, as our goal parameters for evaluating dialyzer's yield. To this purpose, we designed an experimental set... 

    Forced Vibration of Drill String and its Control in Directional Drilling

    , M.Sc. Thesis Sharif University of Technology Salehi, Mohammad Mahdi (Author) ; Moradi, Hamed (Supervisor)
    Abstract
    Nowadays, economical extraction of oil and gas, and their products is an important issue for many countries. Up to now, vertical wells have been used for oil extraction but some wells exist that they cannot be reached by using vertical drilling; for example the wells under a sea. Therefore, this makes the governments and scientists determined to find a new way to reach them. Horizontal drilling is one of the new ways to reach such worthy wells. In this project, dynamics of the horizontal drill string is studied. Then, according to the forces that affect the dynamics of drilling, its vibration is analyzed. After finding the boundary conditions and normal modes of the system with using mode... 

    Control of Bifurcation and Chatter Suppression in Peripheral Milling Process

    , M.Sc. Thesis Sharif University of Technology Bahari Kordabad, Arash (Author) ; Moradi, Hamed (Supervisor)
    Abstract
    Self-excitation vibration or chatter in the milling process is one of the most critical factors in reducing the tool life and surface smoothness. With the change of tool speed or depth of cut, bifurcation phenomena occur at some points (bifurcation points) such that the system behaviour becomes unstable and the chatter is observed. In this study, using nonlinear modelling for cutting forces, two main methods for active control of this process are proposed. The first is an intelligent control based on emotional learning, which is a model-free strategy. In this method, the critic generates a signal (stress signal) using error and its derivative. The purpose of this controller is to reduce the... 

    Simulation of the Operations and Interactions of Agencies Responsible for the Post-Disaster Response and Recovery of the Community

    , M.Sc. Thesis Sharif University of Technology Valaei Sharif, Shahab (Author) ; Kashani, Hamed (Supervisor)

    Energy-Aware Computation Offloading for Wireless Powered Mobile-Edge Computing Systems

    , M.Sc. Thesis Sharif University of Technology Bolourian, Mehdi (Author) ; Shah Mansouri, Hamed (Supervisor)
    Abstract
    Mobile edge computing (MEC) is envisioned to address the computation demands of Internet of Things (IoT) devices. However, it is crucial for the MEC to operate in coordination with the cloud tier to achieve a highly scalable IoT system. In addition, IoT devices require regular maintenance to either recharge or replace their batteries which may not always be feasible. Wireless energy transfer (WET) can provide IoT devices a stable source of energy. Nonetheless, proper scheduling of energy harvesting and efficient allocation of computing resources are the key for sustainable operation of these devices. In this thesis, we introduce a three-tier wireless powered mobile edge computing (WPMEC)... 

    Development of a High-precision Unsaturated Permeameter for Characterizing Two-phase Flow Through Deformable Porous Media

    , M.Sc. Thesis Sharif University of Technology Hassani Motlagh, Amin (Author) ; Sadeghi, Hamed (Supervisor)
    Abstract
    Given that highly deformable natural deposits such as collapsible and swelling soils make up more than one-fifth of the land surface and are generally in unsaturated conditions, behavioral measurement of this type of soil including accurate measurement of its hydraulic properties is important. The challenges of designing and implementing construction infrastructure, along with the most reported financial losses due to the presence of these soils, double the importance of studying the behavior of these soils. The large volume changes of these soils in contact with water (equivalent to a volumetric strain of more than 5%) has been a major challenge for researchers in predicting the... 

    Modeling and Evaluation of the Role of Authorities in Enhancing the Effectiveness of Seismic Vulnerability Reduction Policies

    , M.Sc. Thesis Sharif University of Technology Habibi Moshfegh, Peyman (Author) ; Kashani, Hamed (Supervisor)
    Abstract
    The purpose of study is the modeling and evaluation of the role of authorities in enhancing the effectiveness of seismic vulnerability reduction policies. Seismic vulnerability reduction of infrastructures depends on the measures that must be taken before a disaster occurrence. In addition to increasing disaster preparedness, an important part of the pre-disaster measures is taken to increase the robustness of the infrastructure. In some cases, measures to reduce the vulnerability of infrastructure, such as the resilience of residential buildings, require the coordinated role’s implementation of relevant organizations. Evidence shows that in many cases, policies to reduce the vulnerability... 

    An Energy-saving Control Strategy for Multi-zone Demand Controlled VAV Systems with Optimal Control of air Handling Unit

    , M.Sc. Thesis Sharif University of Technology Omidi Jeze, Hossein (Author) ; Moradi, Hamed (Supervisor)
    Abstract
    Nowadays, due to the increasing use of Air Handling Units (AHU) in buildings, reducing energy consumption and improving the performance of these devices is one of the most important goals of researchers in the field of heating, ventilation and air conditioning (HVAC) technology. The purpose of this project is to design an optimal control system in different parts of the Air Handling Unit in order to provide standard ambient and breathing conditions for the people. Therefore, the mathematical model of the multi-zone space and the equipment of the Air Handling Unit are studied as separate subsystems based on the laws of thermodynamics and heat transfer. The obtained equations provide a... 

    Distributed Robust Model Predictive Control for Multi-zone Air Conditioning Systems

    , M.Sc. Thesis Sharif University of Technology Azim Mezerji, Hojat (Author) ; Moradi, Hamed (Supervisor)
    Abstract
    Optimizing the energy consumption of air conditioning systems has gained great importance in recent years. In addition, maintaining thermal comfort and air quality in buildings is important. The multi-evaporator air conditioning system, which is a direct expansion system, shows the complex and distributed structure of air conditioning systems due to the thermal connection between zones and its large scale. The modeling of these systems is associated with uncertainties. Therefore, designing a suitable control structure for multi-zone systems is very important to achieve optimal energy consumption and maintain comfort conditions in the presence of uncertainty. Model predictive control has been...