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Modification of DFIG's active power control loop for speed control enhancement and inertial frequency response

, Article IEEE Transactions on Sustainable Energy ; Volume 8, Issue 4 , 2017 , Pages 1772-1782 ; 19493029 (ISSN) Ashouri Zadeh, A ; Toulabi, M ; Bahrami, S ; Ranjbar, A. M ; Sharif University of Technology

2017

Abstract

This paper proposes a fuzzy-based speed controller for the doubly fed induction generator (DFIG)-based wind turbines with the rotor speed and wind speed inputs. The controller parameters are optimized using the particle swarm optimization algorithm. To accelerate tracking the maximum power point trajectory, the conventional controller is augmented with a feed-forward compensator, which uses the wind speed input and includes a high-pass filter. The proposed combined speed controller is robust against wind measurement errors and as the accuracy of anemometers increases the speed regulation tends toward the ideal controller. The cutoff frequency of the applied filter is determined considering a...

Design, fabrication, and accuracy of a novel noncovering lock-mechanism bilateral patient-specific drill guide template for nondeformed and deformed thoracic spines

, Article HSS Journal ; Volume 17, Issue 2 , 2021 , Pages 213-222 ; 15563316 (ISSN) Ashouri Sanjani, M ; Mohammadi Moghadam, S ; Azimi, P ; Arjmand, N ; Sharif University of Technology

SAGE Publications Inc 2021

Abstract

Background: Pedicle screw (PS) placement has been widely used in fusion surgeries on the thoracic spine. Achieving cost-effective yet accurate placements through nonradiation techniques remains challenging. Questions/Purposes: Novel noncovering lock-mechanism bilateral vertebra-specific drill guides for PS placement were designed/fabricated, and their accuracy for both nondeformed and deformed thoracic spines was tested. Methods: One nondeformed and 1 severe scoliosis human thoracic spine underwent computed tomographic (CT) scanning, and 2 identical proportions of each were 3-dimensional (3D) printed. Pedicle-specific optimal (no perforation) drilling trajectories were determined on the CT...

Battery energy storage systems and demand response applied to power system frequency control

, Article International Journal of Electrical Power and Energy Systems ; Volume 136 , 2022 ; 01420615 (ISSN) Hosseini, S.A ; Toulabi, M ; Ashouri Zadeh, A ; Ranjbar, A. M ; Sharif University of Technology

Elsevier Ltd 2022

Abstract

In this paper, several new control strategies for employing the battery energy storage systems (BESSs) and demand response (DR) in the load frequency control (LFC) task are proposed. In this way, first, the unit commitment problem considering the BESSs’ constraints in presence of wind farms and responsive loads is solved and the best location and the optimal size of the BESSs as well as the regulation power of the responsive loads are obtained. A rule-based plan is then suggested to improve the frequency regulation considering participation of wind farms. This plan is takes into account different states associated with power system frequency response as well as BESSs’ state of charge (SOC)....

Modeling of a Vague Problem (Floating Breakwater by BEM Analysed) Using ANFIS (Adaptive Neuro-Fuzzy Inference System) and Validation by Fuzzy Boundary Element Method

, M.Sc. Thesis Sharif University of Technology Fereydoon, Maryam (Author) ; Abbaspour Tehrani, Majid (Supervisor)

Abstract

The thesis title is “Modeling of a vague problem (Floating Breakwater by BEM Analysed) using ANFIS (Adaptive Neuro-Fuzzy Inference System) and validation by Fuzzy Boundary Element Method”. In this set of material, more important definitions are described below. When some input data is linguistics, or we have lack of Information or Vagueness, Fuzzy toolbox can alleviate the problem. Fuzzy concept includes several fields and applications like; fuzzy logic, fuzzy sets, fuzzy control, fuzzy arithmetic and fuzzy inference, and the last two applications are used in this thesis. The Neural network is a black box, Neurons that can justify their actions and these artificial brains can grow. The...

An Investigation on Hydrodynamic Locomotion of Trout Fish, Design and Fabrication of Robofish

, M.Sc. Thesis Sharif University of Technology Moosavian, Mortaza (Author) ; Abbaspour, Majid (Supervisor)

Abstract

Human have been thinking to discover all secrets of world, from long time ago. And also the sea exploring and using its resources, including oil and utilization of fish as feed have been the main causes of human interest to ocean. So to access these resources, constructed some equipment to be able to go under water, such as ROV and AUV.
Since the human is concluded that further facts need to synchronize to the world with the natural laws of nature in this area is the best model and teacher; new branch of science called bionic is exploded. For example, look and study of birds in the air movement have produced the fastest aircraft. Same knowledge in the field of marine sciences has...

Design and Constructing a Flap Wave Energy Converter Model

, M.Sc. Thesis Sharif University of Technology Kouhi Anbaran, Soroush (Author) ; Abbaspour, Majid (Supervisor)

Abstract

In the recent decades, because of the reduction of the fossil sources and increasing the environmental pollution, also worldwide population growth and the necessity of energy have made humanbeing to use the Renewable Energy. Wave energy is an opulent source of energy in many parts of the world, especially in Iran.
In this thesis, in the first chapter, different kinds of renewable energy are introduced, and the importance of them is discussed. In the second chapter, the mechanisms of extracting energy by the wave energy converters are investigated, and their types are discussed. Then, in the next chapter, wave equations, wave spctrums and simulation of a flap wave energy converter in...

Modeling Tsunami Wavesand Designinga Warning Systemfor This Phenomenon by UseofIT (Case Study the Sea of Oman)

, M.Sc. Thesis Sharif University of Technology Namdar, Khashayar (Author) ; Abbaspour Tehrani, Majid (Supervisor)

Abstract

Tsunami, like many other natural disasters leaves people a short time for escape. When talking about Tsunami, the escape time is the period it takes for the wave to start moving from the epicenter, change into a giant wave gradually and reach to a cost. In order to minimize damages of this phenomenon, the escaped time has to be estimated without delay. For this purpose the first needed action is modeling the Tsunami waves. Analytical and numerical models and software that are designed based on them do exist. To have an efficient and rapid Tsunami alarming system all of these options are examined in this project. Then having a reliable model quite a few probable scenarios are propounded. The...

Numerical Investigation of Eel Movement

, M.Sc. Thesis Sharif University of Technology Mirzaei Donchali, Ghader (Author) ; Abbaspour, Majid (Supervisor)

Abstract

In this work, we use computational fluid dynamic simulation tools for investigation two dimensional of eel movement. Firstly, the numerical study of smooth particle hydrodynamics was applied for determination drag coefficient and lift coefficient of undulation movement eel body. The initial mesh was manual. So, the effective parameters of eel movement were investigated. The smooth particle hydrodynamic method was not use, because of saving on time. Therefore, fluent software was used. UDF were added to the fluent software, which it can be move the boundary layer of mesh with eel movement. The dynamic mesh tools of fluent software were used. Initial shape had a curvature and utilized for...

Investigating the Application of y-Braced Frames in Seismic Performance of Steel Structures

, Ph.D. Dissertation Sharif University of Technology Majid Zamani, Sohail (Author) ; Vafai, Abolhassan (Supervisor)

Abstract

Finding suitable locations for installing conventional concentric bracings such as X and V, without interfering with building architecture and its openings, is a routine challenge in building design. One of the less known forms of concentric bracings which can be used to solve this issue, is the y-shaped bracing composed of three braces. In the current thesis, results of analytical studies, computer modeling and experimental tests are presented to extend the knowledge of structural behavior of y-bracings. As the first step, effective buckling lengths of braces with rigid connections were found from equilibrium equations incorporating the effect of axial force on rotational stiffness of...

Coordinated Scheduling of Power and Natural Gas Systems Considering Demand Uncertainty

, M.Sc. Thesis Sharif University of Technology Nik Payam, Hossein (Author) ; Rafiee, Majid (Supervisor)

Abstract

The everyday increasing electricity consumption of household and industrial sectors across the world, and also the limited generation capacity and fuel supplies has led electricity companies, whether in private or government sectors, to focus deliberately on power generation planning, its costs, risks and constraints Because of many reasons including high efficiency, low cost of capital investment, expeditious permitting, and operation flexibility of gas-fired generating units, electricity companies prefer them to old ones like coal-fired or oil-fired generating units. Thus natural gas has gained a significant share in the portfolio of electricity generation fuel resources, and it is...

Unified Optimization in Air Traffic Flow Management Problem Under Uncertainties

, M.Sc. Thesis Sharif University of Technology Nazari Pour, Bahareh (Author) ; Rafiee, Majid (Supervisor)

Abstract

Reviewing the literature on air traffic flow management shows that reducing flight delay is one of the main challenges facing air transportation systems. This is due to the high cost of incurring delays. At the first stage, two mixed integer-programming model is presented here that aims to minimize delay cost of air traffic. The first presented model seeks to minimize flights delay costs by choosing an optimal airport configuration and balancing departure and arrival flights and the second presented model solve this problem with the new approach with categorizing the airplane by types and prioritizing them. Numerical examples are solved in CPLEX 12.6 to evaluate models performance. Numeric...

Optimization of Beam Angles and Beam Weight in Intensity Modulated Radiation Therapy

, M.Sc. Thesis Sharif University of Technology Moazzami Goudarzi, Hadis (Author) ; Rafiee, Majid (Supervisor)

Abstract

external radiation therapy is a methods of cancer treatment or improvement of cancer-related complications. various techniques have been developed for external beam radiation therapy. Among which, Intensity Modulated Radiation Therapy (IMRT), due to its ability to adjust the intensity of radiation beams, has a higher capacity to generate appropriate dose distribution based on tumor size and volume. Intensity Modulated Radiation Therapy is one of the most commonly used procedures of delivering radiation to cancerous tissues, with the aim of reaching the prescripted dose in the target volume while minimizing damage to nearby healthy organs. Two decisions are of fundamental importance: to...

Unsteady Hydrodynamic Simulation of Flexible Bodies using Boundary Element Method

, Ph.D. Dissertation Sharif University of Technology Najafi, Saeed (Author) ; Abbaspour Tehrani, Majid (Supervisor)

Abstract

For more than a million years, aquatic animals and specially fishes make undulatory motions in their flexible body to propel themselves. In the recent decays, scientists prove that these mechanisms are more efficient than man-made propulsion systems. A wide variety of artificial vehicles including robotfishes, ROV and etc has been manufactured with inspiring by natural creatures. The Biomimetic science which deals with the study of mechanics and hydrodynamics of living creatures is very important in developing these vehicles. In the present study, numerical software (PANEL3D®), bases on boundary integral equations of potential flow have been developed to simulate hydrodynamic performance of...

Red Tide Development Modelling by MIKE Software (in Persian Gulf)

, M.Sc. Thesis Sharif University of Technology Zohdi, Elahe (Author) ; Abasspour, Majid (Supervisor)

Abstract

Land sourced marine pollution, overexploitation of living marine resources, destruction of habitat and introduction of harmful aquatic organisms and pathogens to new environment had been identified as the four greatest threats to the world’s oceans. Since invasive species can not be cleaned or absorbed in the ocean so, their effects on the environment are irreversible. Red tide is one of the invasive spieces and is a colloquial term used to refer to one of a variety of natural phenomena known as algal bloom. This phenomenon occur in estuarine, marine, or fresh water and algae accumulate rapidly in the water column and resulting in coloration of the surface water, varying in colour normally...

Detection and Estimation of Key Parameters in Traffic Models Using Data Mining Tools

, M.Sc. Thesis Sharif University of Technology Moadab, Amir Hossein (Author) ; Khedmati, Majid (Supervisor)

Abstract

Nowadays, investigating the factors affecting traffic models from different aspects such as metropolitan planning according to the present conditions can help high-level decision-makers and also, at the micro-level, help the travelers to make appropriate decisions for scheduling affairs, route selection, and vehicle type selection. Given the importance of this topic, a framework will be presented in this study that will evaluate the impact of some identified factors such as travel distance, climate, and urban events, and then all these factors will be presented in mathematical formulas. In the end, based on the model, the travel time will be predicted. In this framework, gene expression...

Designing a Comprehensive Quality System and Quality Assurance System in Iran

, M.Sc. Thesis Sharif University of Technology Soltani, Mohammad Saleh (Author) ; Rafiee, Majid (Supervisor)

Abstract

The design of an indicator for "quality rate measurement" has been done in many countries around the world, and the quality rate, like other economic indicators, is subject to public judgment. Prerequisite for the formation of this index is the existence of a "comprehensive system" for quality management in the country, in which the duties and powers of various institutions in the issue of quality are specified and responsible for each process. With this excellent system, quality management is done in an integrated manner and quality can be managed efficiently by providing indicators.Quality assessment, in addition to hearing the customer's voice, requires other aspects, including examining...

Order System Optimizing of Retail Chains

, M.Sc. Thesis Sharif University of Technology Heydari Dehkordi, Farzad (Author) ; Rafiee, Majid (Supervisor)

Abstract

In this article we have investigated an inventory control model with uncertainly in supply and capacity constraints in the volume and variety of goods for supply chain of chain toy stores. The purpose of model is to minimize inventory costs, ordering cost and the cost of shortage to develop an acceptable customer service level. In order to execute replenishment process of goods we propose three periodic review inventory control policies that are implemented automatic, step by step and by using indicators defined in this article. The major difference between the proposed policies and the as-is policy is to use categorization od goods based on specific characteristics. Each of the three...

Operating Room Scheduling with Data driven Robust Optimization Approach

, M.Sc. Thesis Sharif University of Technology Shah Hosseini, Yasaman (Author) ; Rafiee, Majid (Supervisor)

Abstract

In this thesis we will focus on operating room scheduling considering open strategy and uncertainty in the duration of operations for elective patients. A mixed integer programming model will be proposed having the expected list of patients that are going to be scheduled in the specific time horizon and working hours of doctors with the purpose of maximizing the number of scheduled elective patients in the determined time horizon. We aim to assign each patient to an operating room and a start time regarding operating rooms and surgeons working hours, care units capacity constraints and sequencing constraints. We will define three possible ways for each patient after their operations, naming...

Role of Base Metal Composition in Isothermal Solidification Time During Diffusion Brazing of Nickelbased Superalloys

, M.Sc. Thesis Sharif University of Technology Mohammad Kamal, Helia (Author) ; Pouranvari, Majid (Supervisor)

Abstract

The nickel-based superalloys play a key role in the development of aircraft and power-generation turbines due to their exceptional properties of high temperature strength, toughness, crack growth resistance and resistance to degradation corrosive and oxidisation environment.In this thesis, the role of base metal composition in isothermal solidification time during diffusion brazing of Nickel-based super alloys was investigated. To achieve this aim, four different super alloys Hynes230, Hastalloy X, Nimonic 263 and Monel were used in similar joining systems. Systems of H230/H230, HX/HX, C263/C263, and Monel/Monel were joined by BNi2 interlayer at 1323K and for different times, until the...

A Comprehensive Method for Clustering Evolutionary Big Graphs

, M.Sc. Thesis Sharif University of Technology Yazdani Jahromi, Mehdi (Author) ; Khedmati, Majid (Supervisor)

Abstract

Today, many real-world datasets such as social network data and web pages can be shown as graphs. Community detection and clustering of these big graphs has many applications in different fields like recommender systems in social networks and Diag- nosis of diseases in communication networks among proteins. A cluster in a graph is a sub-graph with many internal and few external edges. A new method for local cluster detection around an existing vertex is introduced in this paper. This method applies random walk algorithm for cluster detection. The time complexity of this algorithm based on the graph size is polynomial. Therefore, it can be used for clustering of big graphs. The experimental...