Sharif Digital Repository

One of the most important parts of a cement factory is the cement rotary kiln which plays a key role in quality and quantity of produced cement. In this part, the physical exertion and bilateral movement of air and materials, together with chemical reactions take place. Thus, this system has immensely complex and nonlinear dynamic equations. These equations have not worked out yet. Only in exceptional case; however, a large number of the involved parameters were crossed out and an approximation model was presented instead. This issue caused many problems for designing a cement rotary kiln controller. In this thesis, we employed a nonlinear system identification method for identification,... 

In real-time packet-based communication systems one major problem is misrouted or delayed packets which result in degraded perceived voice quality. If some speech packets are not available on time, the packet is known as lost packet. The easiest task of a network terminal receiver is to replace silence for the duration of lost speech segments. In a high quality communication system in order to avoid quality reduction due to packet loss a suitable method and/or algorithm is needed to replace the missing segments of speech.There are several methods which have been proposed to reduce the effect of packet loss such as Waveform Substitution, High Order Autoregressive, Linear Prediction (LP),... 

The rapid development of scientific areas in this modern era makes the process of finding new field of research slow and laborious for prospective scholars. Thus, having a vision of the future could be helpful to pick a right path for doing researches and ensuring that it is worth to invest in. This thesis seeks to predict research trends by using link prediction approaches on keywords network and discusses about the performance of various algorithms in different situations. Moreover, for the last part of the experiments, novel link prediction algorithms are proposed by the author, enhances the accuracy of prediction results. The data set collected from Sciencedirect and Scopus by a strong... 

Mobile Ad-Hoc Networks (MANETs) have been studied as one of the most important technologies in the mid to late 1990s. There are several research works on types of network traffic modeling and prediction. Therefore, a very important issue is to make prediction on traffic-flows that each node handles. Because of this, prediction permits us to improve and increase the performance of the network. This project is a contributing effort to improve the traffic packets prediction by Neural Networks in MANET. The main goal of this thesis is about the recovery of data after crisis in phenomenal roads and highways. Our goal is recognizing phenomenal crisis-points in roads. In this thesis packets are... 

In this project we have worked on the new architecture of the auction based resource scheduling, from the bidders point of view. The performance of different bidding strategies for the resources which participate in reverse auction system has been investigated; our main parameter for evaluating different bidding strategies is the amount of the profit gained by resources which follow such strategies. The main historical bidding strategies are created based on two famous predictors ES and AUTO-REGRESSION. In addition a game theory approach has been proposed. We have shown that our bidding algorithm (based on the sequential game model) reaches to an equilibrium point if all the bidders follow... 

Due to the energy crisis in recent years, much of which is due to excessive energy consumption in the air conditioning of buildings, many studies have been conducted from the perspective of engineering sciences on the subject of insulation and optimization of buildings. This study aims to investigate the conditions of thermal comfort from the mental and psychological perspective of human beings, which is the basis of the individual's decision to accept thermal adaptation behavior in the standard temperature range. In this study, the thermal adaptation model was designed on the theory of programmed behavior, which can explain the adaptation of individuals to the comfort temperature region.... 

In this project, a comprehensive methodology is developed to present the lifetime management and optimization framework for hybrid renewable energy systems. The main purpose of this work is to minimize the lifetime cost and improve the system reliability based on the interaction between different optimization levels related to different steps in the system lifetime. The proposed methodology is generally presented by providing a connection between the three specified optimization levels: 1) Planning: including design and long-term optimization models which is performed before system operation, 2) Real-time operation: By employing the receding horizon optimization which is applied from the... 

Considering the increasing importance of energy conservation in recent decades, different technologies regarding energy system have been developed to satisfy this goal. Building section is responsible for a big portion of final energy consumption and greenhouse gasses emission around the globe. Utilizing energy consumption reduction techniques in the building sector is among the foremost solutions to achieve the energy conservation potentials in this sector which would be followed by a decline in greenhouse emissions. Considering the contribution of heating and coling systems in a building’s energy use, optimizing these systems could have a huge effect on a building’s final energy... 

Following Three Mile Island (TMI) accident in 1979, first severe accident (SA) in Nuclear Power Plants (NPPs), Accident Management Support Tools (AMSTs) were developed and installed in a number of NPPs. Lessons learned from Fukushima accident highlighted importance of Accident Management (AM) in mitigation severe radiological consequences after a SA and suggested reconsiderations of AM program which in turn created the need for AMSTs adaption and modernization. An efficient AMSTs should have the following principal capabilities: (1) Identification of accidents and diagnosis of the plant damage state (PDS), (2) Prediction of accident progress path and (3) Source term analysis and prediction... 

Analysis of neutronic and thermal-hydraulics fluctuations has various applications in calculation or measurement of the core dynamical parameters (temperature reactivity coefficients) furthermore it is applicable in thermal-hydraulics surveillance and diagnostics. Experience of the Fukushima Dai-ichi plant and the lessons learned from the European stress tests, demonstrated that alternative and various tools and methods are needed for the reactor's condition identification. In this paper the feasibility of development of an alternative accident monitoring via eminent coupling of neutron and thermal-hydraulics noise is proposed. and it is programming a simple simulator for calculating... 

This thesis focuses on the development of a flight formation control algorithm and obstacle avoidance of a UAV team using fuzzy predictive artificial potential field (FPAPF) method. One of the common methods for path generation and obstacle avoidance is the artificial potential field (APF) method. The basis of the APF method is that the UAV is attracted to the target point and repelled from the obstacles by using the potential fields of attraction and repulsion. The popularity of this method is due to its computational simplicity and efficiency. The APF method has limitations due to constant attraction and repulsion coefficients. The proposed real-time FPAPF method uses fuzzy logic to... 

This thesis proposes a robust model predictive controller for airplanes that can handle severe crosswind and indeterminate conditions, such as ground effect, without prior knowledge of wind direction and magnitude. The controller is a combination of extended dynamic model control (EDMC) model predictive control and differential game using a 6DOF nonlinear airplane model developed in MATLAB. The controller's cost function is designed to minimize controller effort during maximum disturbance and tracking error of desired outputs simultaneously. Testing for the landing phase is performed using a control structure in MATLAB for the longitudinal and lateral planes of the airplane. The structure... 

In this research, a cooperative terminal guidance algorithm has been derived for simultaneous multi-interceptor collision with a target. This algorithm is obtained using the combination of model predictive control method and differential game theory. One of the features of this method is the calculation of the optimal guidance command in the form of an explicit relationship. Another feature of this method is its resistance to disturbances due to the use of differential game theory. The first innovation of this research is the use of this hybrid method to create a guidance algorithm, even in the non-cooperative guidance problem. The next innovation is in creating a cooperative terminal... 

This research presents three new guidance laws for trajectory tracking of an unmanned aerial vehicle in the presence of wind disturbances. The first method is a linear combination of line-of-sight and velocity-pursuit guidance laws, the parameters of which are tuned using a fuzzy system in an online manner. The second method is an adaptive optimal guidance law based on the differential game theory. The third method (main method) is a model predictive guidance law based on the differential game theory. In the main method, linear point mass equations of motion are used to predict the future path of the vehicle. Also, the linear model predictive control is used to achieve an optimal analytical... 

The purpose of this thesis is to control altitude and attitude of a Tilt Tri-Rotor UAV in rotorcraft mode and control of altitude, attitude and forward velocity in transition mode (from rotorcraft mode to cruise) by using model predictive control. First, the detailed mathematical model is obtained by the Newton-Euler equations of motion, in both rotorcraft and transition modes. In the next step, a MIMO model predictive controller has been designed, considering input constraints. Then, since, robustness of the model-based control approach is an important challenge, the performance of the controller is presented in the presence of model uncertainties and wind disturbances. The results indicate... 

In this study, a multiple model wind estimator is proposed to detect the wind type and to estimate the wind components as well as the states of a fixed-wing UAV without any direct measurement of the air data. Then, the identified wind model and the estimated states are compensated in the heuristic nonlinear model predictive controller during landing phase. For this purpose, a static multiple model approach is taken, comprised of four independent extended Kalman filters, each one is estimating the wind based on one of the four wind models including a constant wind, a “1-cosine” model, a wind shear and a microburst.Moreover, a new heuristic multiple model filter, called Multiple Model Extended... 

In this study, novel algorithms are presented for nonlinear parameter varying systems with uncertainty in the model predictive control using heuristic algorithms. To this end, some algorithms are developed which provide the possibility of estimating simultaneously states and control signal of the stochastic nonlinear systems. Then, the model predictive control algorithm is presented for stochastic nonlinear systems with uncertainty to estimate uncertainty and compensate it using ant colony optimization. Next, the model predictive control algorithm is developed for nonlinear system with matched bounded uncertainty using particle swarm optimization. Performance of the developed controllers is... 

A comprehensive adaptive flight control system in the presence of internal and external disturbances is introduced in this dissertation. In this regard, two different approaches, namely, a centralized model and a multi-model structure are developed using the capabilities of neuro-fuzzy systems in order to identify the dynamic model of an air vehicle after the fault occurrence in the simultaneous presence of model uncertainties and external disturbances. Subsequently, a Model Predictive Control (MPC) approach is designed for the identified model, which can satisfactorily deal with nonlinear and multi-variable nature of the system. In addition, system constraints can be effectively considered... 

This dissertation investigates the Multiple-Horizon Multiple-Model Predictive Control method and its application in soft landing problem on an irregular-shaped asteroid. In this way, a predictive framework including a heuristic guidance law named Predictive Path Planning and Multiple-Horizon Multiple-Model Predictive Control (MHMM-PC) as the control scheme is introduced for soft landing on an asteroid. Obviously, reducing the fuel consumption is a priority in space missions. Thus, the employed control framework should minimize the required control effort. Furthermore, the control method should be robust enough to deal with the effects of model uncertainties and disturbances. The unique... 

Reliability evaluation is a key factor in serviceability and safety analysis of air vehicles. Structural health monitoring methods have grown to a degree of maturity in many industries. However, there is a challenging interest to tie in SHM with reliability assessment. In this respect, consideration of stochastic structural dynamics with SHM data and random loadings opens a new chapter in failure prevention. The current study focuses on the stochastic behavior of structures as a way to relate SHM data with reliability. In this respect, uncertain factors such as atmospheric turbulence, structural parameters, and sensor outputs are considered in the process of reliability assessment. Firstly,...