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    Trajectory control of autonomous mobile robots considering disturbance with machine learning agents

    , Article Journal of the Brazilian Society of Mechanical Sciences and Engineering ; Volume 45, Issue 6 , 2023 ; 16785878 (ISSN) Tahmasbi, M ; Sharif University of Technology
    Springer Science and Business Media Deutschland GmbH  2023
    Abstract
    Mobile robots as automatic machines have the capability to move around various environments and have considered because of wide range of applications in the industrial settings. It is vital for a mobile robot to determine its errors in indeterminate conditions and provide a robust and high performance controller along with trajectory control. Hence, the research has attempted to give a learning-based controller method for wheeled mobile robots in the presence of disturbance. The proposed method, use LQR controller and the Bat algorithm based on machine learning agents to calculate and identify control errors and satisfy the stability. The wheeled mobile robot should track the reference path... 

    Behavior of Angle Shear Connectors

    , M.Sc. Thesis Sharif University of Technology Tahmasbi, Farzad (Author) ; Maleki, Shervin (Supervisor)
    Abstract
    The application of composite systems has rapidly advanced in bridge and building construction. Shear connectors are the most basic parts of the composite systems.The connectors transfer the shear forces between the slab and the beam. They also prevent separation of the slab from the beam.
    Therefore researchers have done widespread studies on the behavior of shear connectors and their load carrying capacity. Steel angles are one of the shear connectors that can be used incompositesystems. Only limited number ofstudies has investigated thebehavior of thistype of connector.
    The purpose of this thesis is to investigate the behavior of angle shear connectors embedded in solid concrete... 

    Review of Contemporary Islamology Streams as Rational Traditions, Considering Macintyre View Points

    , M.Sc. Thesis Sharif University of Technology Tahmasbi, Mahdi (Author) ; Golshani, Mahdi (Supervisor)
    Abstract
    Shia theology has gone through different transformations throughout history. In the contemprorary age diverse studies have been carried out in order to discribe it’s preceding changes and future transformations. This tesis tends to show at first that “MacIntyre’s method of historical-philosophical study” is an overally justified model for such studeis, in comparison with the two other models of “Kuhn’s model of scientific revolutions” & “Lakatos’s research programs.” Afterwards, this model has been used for the study of shia theology and a brief narration of the rationality traditions of shia theology through the Iranian tradition has been given. The focus of this section has been on the... 

    Digital Marketing Management in Businesses and Startups Using Dynamic Systems Modeling

    , M.Sc. Thesis Sharif University of Technology Tahmasbi, Sepehr (Author) ; Shadrokh, Shahram (Supervisor)
    Abstract
    As today's world becomes more digital in every way, digital marketing has become a thriving industry, and digital marketing has become an important part of the world of digital business. Given the importance of this issue and the prominent role of startups in the today’s business world, in this project we discuss about digital marketing in start-ups business with a view to health sector using dynamic systems modeling. First, the effective variables are determined, then the relationships between them are determined and the model is designed. Finally, after analyzing the model factors and determining the extent and type of its impact on the main factors and variables, smooth the way to create... 

    Critical graphs in index coding

    , Article IEEE International Symposium on Information Theory - Proceedings ; 2014 , p. 281-285 Tahmasbi, M ; Shahrasbi, A ; Gohari, A ; Sharif University of Technology
    2014
    Abstract
    In this paper we define critical graphs as minimal graphs that support a given set of rates for the index coding problem, and study them for both the one-shot and asymptotic setups. For the case of equal rates, we find the critical graph with minimum number of edges for both one-shot and asymptotic cases. For the general case of possibly distinct rates, we show that for one-shot and asymptotic linear index coding, as well as asymptotic non-linear index coding, each critical graph is a union of disjoint strongly connected subgraphs (USCS). On the other hand, we identify a non-USCS critical graph for a one-shot non-linear index coding problem. In addition, we show that the capacity region of... 

    Optimum power of a nonlinear piezomagnetoelastic energy harvester with using multidisciplinary optimization algorithms

    , Article Journal of Intelligent Material Systems and Structures ; 2020 Tahmasbi, M ; Jamshiddoust, A ; Farrokhabadi, A ; Sharif University of Technology
    SAGE Publications Ltd  2020
    Abstract
    Energy-harvesting devices have been widely used to generate electrical power. Through the use of energy harvesting techniques, ambient vibration energy can be captured and converted into usable electricity in order to create self-powering systems. In the present study, to further improve the efficiency of energy-harvesting devices, a nonlinear piezomagnetoelastic energy harvester is proposed in two different configurations that is parallel and series. In order to optimize the generated electrical power, the physical parameters of the harvester are chosen as the design variables. Classical and Metaheuristic algorithms, namely, random search, genetic algorithm, and simulated annealing are... 

    Optimum power of a nonlinear piezomagnetoelastic energy harvester with using multidisciplinary optimization algorithms

    , Article Journal of Intelligent Material Systems and Structures ; Volume 32, Issue 8 , 2021 , Pages 889-903 ; 1045389X (ISSN) Tahmasbi, M ; Jamshiddoust, A ; Farrokhabadi, A ; Sharif University of Technology
    SAGE Publications Ltd  2021
    Abstract
    Energy-harvesting devices have been widely used to generate electrical power. Through the use of energy harvesting techniques, ambient vibration energy can be captured and converted into usable electricity in order to create self-powering systems. In the present study, to further improve the efficiency of energy-harvesting devices, a nonlinear piezomagnetoelastic energy harvester is proposed in two different configurations that is parallel and series. In order to optimize the generated electrical power, the physical parameters of the harvester are chosen as the design variables. Classical and Metaheuristic algorithms, namely, random search, genetic algorithm, and simulated annealing are... 

    A new approach to multi-objective optimisation method in PEM fuel cell

    , Article International Journal of Sustainable Energy ; Volume 34, Issue 5 , Jul , 2015 , Pages 283-297 ; 14786451 (ISSN) Tahmasbi, A. A ; Hoseini, A ; Roshandel, R ; Sharif University of Technology
    Taylor and Francis Ltd  2015
    Abstract
    This paper presents an optimisation model for polymer electrolyte membrane fuel cell system based on simultaneous power maximisation and cost minimisation. The results show that, by employing appropriate relation between the objectives, the innovative design could be proposed. Genetic algorithm is applied to solve the optimisation problem. Power maximisation results reveal that at maximum amount of power (1.95 kW), unit cost of energy is $0.64. In contrast, minimisation of cost decreases unit cost of energy to $0.33. In this condition, output power is reduced approximately to 0.93 kW. To consider both optimisation problems concurrently, weighting method and Pareto set are employed. Our... 

    Ranking Realizations of Reservoir Model by Using Well Test Data

    , M.Sc. Thesis Sharif University of Technology Tahmasbi, Mehran (Author) ; Masihi, Mohsen (Supervisor) ; Shad, Saeed (Co-Advisor)
    Abstract
    Characteristic of the reservoir, including the important discussion in the oil industry, is widely practiced in the modeling, simulation and EOR. One of the methods fordetermining the specifications of the reservoir is geostatistical technique. This means that a large number of realizations of the reservoir model to assess the uncertainty in reservoir descriptions of performance predictions should be made.However flow simulation of all these realizations is very difficult due to cost and time calculations.To mend the problem, we use ranking realization that finally a minor number of realizations are selected and flow simulation is used to them.In this project, we use streamline simulation to... 

    Hybrid Switching of Harvesting Energy Systems Based on Peizoelectric Material

    , M.Sc. Thesis Sharif University of Technology Tahmasbi, Mohammad (Author) ; Alasty, Aria (Supervisor) ; Salarieh, Hasan (Supervisor)
    Abstract
    For many low-powered portable and wireless electronic applications the finite energy density of chemical batteries places limits on their functional lifetime. Through the use of energy harvesting techniques, ambient vibration energy can be captured and converted into usable electricity in order to create self-powering systems which are not limited by finite battery energy. Typical energy harvesting systems are composed of two components, a transducer that converts the mechanical vibrations into electrical energy and a power converter that efficiently delivers the harvested energy to the electronic load. The practical design of energy harvesting systems must include both components and... 

    Modeling Propagation of Cardiac Action Potential at Cellular Level

    , M.Sc. Thesis Sharif University of Technology Farahani, Mojtaba (Author) ; Jahed, Mehran (Supervisor)
    Abstract
    Heartbeat is the result of contractions of over 10 billion cardiac cells. These cells’ cytoplasms are connected to each other by gap junctions which are arrays of intercellular protein channels. Thus action potential can propagate from one cell to another and cause its contraction. In core-conductor model, one-dimensional microscopic representation of cardiac tissue, cells are attached to each other to form a ladder network. The parallel elements are connected to each other by series resistors which represent gap junctions. These resistors are nearly always considered as static elements. In this thesis I have investigated the effects of incorporating the dynamicity of gap junction resistors... 

    Distributed Cardiovascular System Modeling

    , M.Sc. Thesis Sharif University of Technology Khani, Mehrdad (Author) ; Jahed, Mehran (Supervisor)
    Abstract
    Simulation of cardiovascular system functionality during various physiological conditions is essential at different diagnostic and clinical levels. A first step in studying the roots of cardiovascular diseases and abnormal activity is to study a practical yet complete model of the cardiovascular system. In this thesis we introduced a new approach for defining the distributed model of the cardiovascular system. Initially, we chose an appropriate subsystem, namely Arch of Aorta, and proposed a distributed model for it. The elements of the proposed model were nonlinear RLC elements that simulate resistance, blood viscosity and vessel elasticity respectively. To minimize the system complexity,... 

    Risk Breakdown Structure (RBS) Identification and Designing for projects

    , M.Sc. Thesis Sharif University of Technology Abdi, Mehdi (Author) ; Sepehri, Mehran (Supervisor)
    Abstract
    To actualize and making the outputs of a project effectual, it is necessary to conduct an effective management during a project. This case may not be possible without accurately planning for activities, management and controlling all phases of a project ignoring the risk management of that project. If risks of a project cannot be detected before conducting a project, it is possible to challenge the performance and even effectiveness of the project. In current conditions, the most important problem of managers and executives of construction projects through the country is risk management of projects, not acknowledging with definitions of risk, models of risk management and lack of a model for... 

    Introducing a suitable Controller for Rowing Activity in Patients with Spinal CordInjuries using FES

    , M.Sc. Thesis Sharif University of Technology Zarei, Mohammad (Author) ; Jahed, Mehran (Supervisor)
    Abstract
    Disconnections in neural paths from the central nervous system to the muscles or vice versa cause different neuropathies, thus paralysis in different limbs may occur. As a result of the lack of muscular activity and the decrease in blood perfusion in paralyzed limbs, problems like osteoporosis, increase in the risk of breaking, decline in muscle size, cardiovascular diseases, renal dysfunction, bedsores, etc may happen. In order to induce movement in paralyzed limbs, thus preventingmentioned problems, rowing exercise through Functional Electrical Stimulation (FES) may be utilized. In FES, electrical Stimulation using current stimulating pulses is applied to contracting and relaxing muscles,... 

    Performance Management of HSE Management System based on BSC Framework-the Case Study of Mapna Corporation

    , M.Sc. Thesis Sharif University of Technology Naseri, Amin (Author) ; Sepehri, Mehran (Supervisor)
    Abstract
    A Balanced Scorecard (BSC) model is proposed to evaluate performance of Health, Safety and Environment (HSE) management systems. This model includes key performance indicators at three integrated levels. It has been tested and verified in a project-based organization in Iran, active in the area of power and energy. Results show that the company has done well in implementing HSE management processes, but no so well in growth and learning. This model may be used as a basis for comparing different companies and various proposed programs in the field of HSE management systems. The model includes indicators and sub-indicators in each category particularly related to stakeholders, processes, and... 

    Functional Modeling of Normal and CHF Heart and Control of Total Artificial Heart- An Optimizing Approach

    , Ph.D. Dissertation Sharif University of Technology Ravanshadi, Samin (Author) ; Jahed, Mehran (Supervisor)
    Abstract
    World-wide, Congestive Heart Failure (CHF) takes hundreds of thousands of lives each year. This chronic heart disease causes poor performance of the heart and insufficient blood pumping to the organs. A significant percentage of patients with CHF require heart transplants for their survival. The high cost of heart transplant, shortage of donor hearts and possibility of its rejection by recipients are serious problems of this type of treatment. Therefore a large number of heart patients are potential beneficiaries of artificial blood pumps such as Ventricular Assist Device (VAD) and Total Artificial Heart (TAH). Performance of these systems must be compliant and complementary to the existing... 

    Identifying Affecting HR Factors on Unsuccessful Reengineering Projects

    , M.Sc. Thesis Sharif University of Technology Kordrostami, Melika (Author) ; Sepehri, Mehran (Supervisor)
    Abstract
    In this study, factors which lead in failures in reengineering processes in project based companies have been investigated. The research used qualitative methods, and finally using theme analysis to identify the main factors.Consequently, the main causes of failure of re-engineering projects have been identified and classified in six basic categories including: organizational leadership, planning, human resources management, mental models causing resistance, culture and organizational climate and communication. That each of these themes includes some subset of the agents it represents. In this study, a suitable pattern for organizations which intend to perform reengineering has been... 

    Applying Tandem CONWIP Policy to Assembly Supply Chain

    , M.Sc. Thesis Sharif University of Technology Shokoohyar, Sina (Author) ; Sepehri, Mehran (Supervisor)
    Abstract
    Supply chain management has been developed extensively in second half of last century and the development has been continued up to present century. Nowadays Development and conformity of production and inventory control methods with JIT philosophy in production line level is one of the topics that received much attention from researchers. An increasing interest in the scope of JIT philosophy is on the extension and adaptation of Pull policies such as Kanban and CONWIP for materials and production control. In a real-life environment, companies are subjected to various types of uncertainties such as stochastic processing times and variable demand. This uncertain environment could cause lots... 

    Joint Segmentation and Motion Estimation of Cardiac Cine MR Image Sequences

    , Ph.D. Dissertation Sharif University of Technology Eslami, Abouzar (Author) ; Jahed, Mehran (Supervisor)
    Abstract
    In this study a variational framework for joint segmentation and motion estimation is provided for inspecting heart in Cine MRI sequences. In the first work, a functional including Mumford-Shah segmentation and optical flow based dense motion estimation is proposed. However, the motion estimation technique is replaced with warping estimation in the second work to reach in more regular and smooth motion field based on tracking of cardiac boundaries. Both of these functionals are then approximated by using the phase-field method to make them suitable for extracting Euler-Lagrange equations. Numerical solution to the optimization problem, when the time and image spaces are discretized by finite... 

    Dynamics and Control of Needle Movement in Percutaneous Interaction with Prostate Tissue

    , Ph.D. Dissertation Sharif University of Technology Maghsoudi, Arash (Author) ; Jahed, Mehran (Supervisor)
    Abstract
    In many modern medical procedures, needle insertion is an inevitable part of the diagnosis or treatment protocols. The accuracy of the needle insertion is adversely affected by a number of factors. A needle, frequently assumed to be flexible, is inserted into a soft tissue and induces complex mechanical interactions that may result in considerable uncertainties. Tissue intrinsic characteristics as well as its deformation and rotation may cause dramatic complexities. This work considers the needle movement inside the tissue from the dynamics and control point of view. The proposed approach can be regarded as an initial step towards automation of needle insertion procedures; it can also be...