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An Efficient Algorithm to Solve the Joint Road Reopening and Emergency Relief Problem after a Severe Earthquake in Urban Areas
, M.Sc. Thesis Sharif University of Technology ; Poorzahedi, Hossein (Supervisor)
Abstract
The purpose of this study is to solve the problem of allocating relief teams to reopen damaged roads and remove debris from damaged areas after the earthquake for large cities. In the deteriorated areas of large metropolises, severe earthquakes may damage links, which causes some nodes to separate from the network. In this research, by using an Ant System meta-heuristic algorithm, a joint problem of damaged link restoration and demolished zone debries removal problem for search and rescue of the trapped population in an earthquake is solved. Ant System parameters are calibrated, and sensitivity analyses are done for the number of relief teams, earthquake intensity. The results of 1000...
On the links of vertices in eimplicial d-complexes embeddable in the euclidean 2d-space
, Article Discrete and Computational Geometry ; Volume 59, Issue 3 , 2018 , Pages 663-679 ; 01795376 (ISSN) ; Sharif University of Technology
Springer New York LLC
2018
Abstract
We consider d-dimensional simplicial complexes which can be PL embedded in the 2d-dimensional Euclidean space. In short, we show that in any such complex, for any three vertices, the intersection of the link-complexes of the vertices is linklessly embeddable in the (2 d- 1 ) -dimensional Euclidean space. In addition, we use similar considerations on links of vertices to derive a new asymptotic upper bound on the total number of d-simplices in an (continuously) embeddable complex in 2d-space with n vertices, improving known upper bounds, for all d≥ 2. Moreover, we show that the same asymptotic bound also applies to the size of d-complexes linklessly embeddable in the (2 d+ 1 ) -dimensional...
On the links of vertices in simplicial d-complexes embeddable in the euclidean 2d-space
, Article Discrete and Computational Geometry ; 2017 , Pages 1-17 ; 01795376 (ISSN) ; Sharif University of Technology
2017
Abstract
We consider d-dimensional simplicial complexes which can be PL embedded in the 2d-dimensional Euclidean space. In short, we show that in any such complex, for any three vertices, the intersection of the link-complexes of the vertices is linklessly embeddable in the (Formula presented.)-dimensional Euclidean space. In addition, we use similar considerations on links of vertices to derive a new asymptotic upper bound on the total number of d-simplices in an (continuously) embeddable complex in 2d-space with n vertices, improving known upper bounds, for all (Formula presented.). Moreover, we show that the same asymptotic bound also applies to the size of d-complexes linklessly embeddable in the...
Fuzzy adaptive sliding mode control for a class of uncertain nonlinear MIMO systems with application to a 2DOF twin propeller
, Article 10th International Fuzzy Systems Association World Congress, IFSA 2003, 30 June 2003 through 2 July 2003 ; Volume 2715 , 2003 , Pages 500-507 ; 03029743 (ISSN); 3540403833 (ISBN); 9783540403838 (ISBN) ; Bolandhemat, H ; Dadkhah Tehrani, N ; Sharif University of Technology
Springer Verlag
2003
Abstract
A practical design method is presented which used the fuzzy logic advantages in adaptation of sliding mode control. The combined Fuzzy Adaptive Sliding Control (FASC) is designed in such a way to enhance satisfactory sliding performance and robustness with good level of chattering alleviation. The design approach is valid for a class of nonlinear uncertain MIMO systems. This control algorithm does not require the system model. A supervisory term is appended to the controller to assure the stability of fuzzy sliding mode control through Lyapunov theory. The design approach has been applied to a 2DOF twin propeler system with large uncertainty. Simulation results verified effectiveness of...
Preparation of Acrylamide Copolymers Containing Highly Hydrophobic Monomers and Study on Their Drag Reduction Properties
, M.Sc. Thesis Sharif University of Technology ; Ramazani Saadatabadi, Ahmad (Supervisor)
Abstract
With the rapid increase of energy consumption, energy problem has been a global issue, which must be faced with and solved. One way to prevent energy consumption is to reduce drag in the flow inside the pipes by using polymer additives; Because the Transportation of liquids using pipeline technology has its limitations, since turbulent flow inside the pipe involves a loss of energy. The net effect of this is that increasing the energy applied to the flow does not increase the flow rate. For this purpose, copolymers and terpolymers of hydrophilic acrylamide monomers along with hydrophobic styrene and hydrophilic maleic anhydride monomers were synthesized by reverse emulsion polymerization...
Control of Nonlinear Dynamic Systems over the Packet Erasure Channel: Applications in Remote Control of Autonomous Vehicles
, Ph.D. Dissertation Sharif University of Technology ; Farhadi, Alireza (Supervisor)
Abstract
Abstract: In this dissertation, the problem of tracking and stabilization of nonlinear dynamic systems over the packet erasure channel is addressed. Using the idea of linearization of nonlinear system around current working point, and by the design of an encoder, decoder, and controller for the linearized system, state tracking and reference tracking of the nonlinear system are addressed. To prove the traking and stability of the system, the strong law of large numbers and the dwell time approach are used. By computer simulations, the theoretical development is applied on the nonlinear dynamic of the unicycle model, which is a suitable model for autonomous vehicles, such as drones, unmanned...
Design and fabrication of a new multi-loop saddle coil for 1.5 T MRI
, Article Review of Scientific Instruments ; Volume 90, Issue 11 , 2019 ; 00346748 (ISSN) ; Mohammadzadeh, M ; Sharif University of Technology
American Institute of Physics Inc
2019
Abstract
Radiofrequency coils provide high-resolution magnetic resonance (MR) imaging of human tissues. A small RF coil produces MR images with a higher resolution compared to the commercial volume MR coils from mass limited samples. Signal to noise ratio (SNR) plays a key role in the optimal design of receiver radiofrequency coils. In this work, we present a three-loop saddle coil suitable for MR imaging of digits of the human body. The geometry of the introduced coil is optimized to achieve the highest SNR. The coil performance is evaluated through comparing the measured SNR maps of the optimal coil derived from MR images of a saline phantom with the corresponding measured SNR maps of a commercial...
Measurement and control of nonlinear dynamic systems over the internet (IoT): Applications in remote control of autonomous vehicles
, Article Automatica ; Volume 95 , 2018 , Pages 93-103 ; 00051098 (ISSN) ; Farhadi, A ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
This paper presents a new technique for almost sure asymptotic state tracking, stability and reference tracking of nonlinear dynamic systems by remote controller over the packet erasure channel, which is an abstract model for transmission via WiFi and the Internet. By implementing a suitable linearization method, a proper encoder and decoder are presented for tracking the state trajectory of nonlinear systems at the end of communication link when the measurements are sent through the packet erasure channel. Then, a controller for reference tracking of the system is designed. In the proposed technique linearization is applied when the error between the states and an estimate of these states...
Reference tracking of nonlinear dynamic systems over AWGN channel using the describing function
, Article Scientia Iranica ; Volume 26, Issue 3 D , 2019 , Pages 1724-1735 ; 10263098 (ISSN) ; Farhadi, A ; Sharif University of Technology
Sharif University of Technology
2019
Abstract
This paper presents a new technique for mean square asymptotic reference tracking of nonlinear dynamic systems over Additive White Gaussian Noise (AWGN) channel. The nonlinear dynamic system has periodic outputs and sinusoidal inputs and is cascaded with a bandpass filter acting as an encoder. By using the describing function method, the nonlinear dynamic system is represented by an equivalent linear dynamic system. Then, for this system, a mean square asymptotic reference tracking technique, including an encoder, a decoder, and a controller, is presented. It is shown that the proposed reference tracking technique results in mean square asymptotic reference tracking of nonlinear dynamic...
Reference tracking of nonlinear dynamic systems over AWGN channel using the describing function
, Article Scientia Iranica ; Volume 26, Issue 3 D , 2019 , Pages 1724-1735 ; 10263098 (ISSN) ; Farhadi, A ; Sharif University of Technology
Sharif University of Technology
2019
Abstract
This paper presents a new technique for mean square asymptotic reference tracking of nonlinear dynamic systems over Additive White Gaussian Noise (AWGN) channel. The nonlinear dynamic system has periodic outputs and sinusoidal inputs and is cascaded with a bandpass filter acting as an encoder. By using the describing function method, the nonlinear dynamic system is represented by an equivalent linear dynamic system. Then, for this system, a mean square asymptotic reference tracking technique, including an encoder, a decoder, and a controller, is presented. It is shown that the proposed reference tracking technique results in mean square asymptotic reference tracking of nonlinear dynamic...
Numerical Investigation of Parameters Affecting the Behavior of Backdraft Phenomena and Its Extinguishing
, M.Sc. Thesis Sharif University of Technology ; Farhanieh, Bijan (Supervisor)
Abstract
Fires in buildings and closed environments are considered as the most important types of fires due to the possibility of the presence of people and the possibility of life-threatening. Understanding and predicting fire behavior is critical to preventing damage. Backdraft is a special phenomenon of fire that occurs in a chamber with limited ventilation. In a closed environment where there is fire, over time, due to the closed doors and windows, the oxygen required for combustion decreases and as a result, semi-combustible materials can be dangerously exposed to the environment with flammable vapors and gases. Fill and when sufficient air reaches this chamber, a sudden explosion or the same...
New coding scheme for the state estimation and reference tracking of nonlinear dynamic systems over the packet erasure channel (IoT): Applications in tele-operation of autonomous vehicles
, Article European Journal of Control ; 2020 ; Farhadi, A ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
This paper presents a new technique for the state estimation and reference tracking of nonlinear dynamic systems over the packet erasure channel, which is an abstract model for transmission via the Internet, WiFi wireless network and ZigBee modules. A new encoder and decoder for real time state estimation of nonlinear dynamic systems at the end of communication link when the measurements are sent through the limited capacity erasure channel, are presented. Then, using the available results from control theory, a controller for reference tracking and hence the stability of the system is also designed. That is, for nonlinear systems, almost sure asymptotic state estimation and reference...
Tele-operation of autonomous vehicles over additive white Gaussian noise channel
, Article Scientia Iranica ; Volume 28, Issue 3 , 2021 , Pages 1592-1605 ; 10263098 (ISSN) ; Farhadi, A ; Sharif University of Technology
Sharif University of Technology
2021
Abstract
This paper is concerned with the tele-operation of autonomous vehicles over analog Additive White Gaussian Noise (AWGN) channel, which is subject to transmission noise and power constraint. The nonlinear dynamic of autonomous vehicles is described by the unicycle model and is cascaded with a bandpass filter acting as encoder. Using the describing function method, the nonlinear dynamic of autonomous vehicles is represented by an approximate linear system. Then, the available results for linear control over analog AWGN channel are extended to account for linear continuous time systems with non-real valued and multiple real valued eigenvalues and for tracking a non-zero reference signal....
New coding scheme for the state estimation and reference tracking of nonlinear dynamic systems over the packet erasure channel (IoT): Applications in tele-operation of autonomous vehicles
, Article European Journal of Control ; Volume 57 , 2021 , Pages 242-252 ; 09473580 (ISSN) ; Farhadi, A ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
This paper presents a new technique for the state estimation and reference tracking of nonlinear dynamic systems over the packet erasure channel, which is an abstract model for transmission via the Internet, WiFi wireless network and ZigBee modules. A new encoder and decoder for real time state estimation of nonlinear dynamic systems at the end of communication link when the measurements are sent through the limited capacity erasure channel, are presented. Then, using the available results from control theory, a controller for reference tracking and hence the stability of the system is also designed. That is, for nonlinear systems, almost sure asymptotic state estimation and reference...
A queuing network model for minimizing the total makespan of computational grids
, Article Computers and Electrical Engineering ; Volume 38, Issue 4 , 2012 , Pages 827-839 ; 00457906 (ISSN) ; Entezari Maleki, R ; Sharif University of Technology
2012
Abstract
This paper offers a mathematical solution based on queuing theory and a generalized stochastic Petri net model to minimize the total makespan of the grid computing environments. A grid manager could minimize the total makespan through cautious distribution of subtasks to the grid resources. Subtask arrival rates depend on the arrival rate of the grid tasks submitted to the grid manager, local tasks directly submitted to the grid resources and the processing speed of the resources. Modeling the grid environment using queuing network, the steady state analysis of the network will result in the mean response time of the resources. Therefore, the total makespan could be minimized by minimizing...
A ray tracing acceleration technique for wave propagation modeling
, Article APMC 2009 - Asia Pacific Microwave Conference 2009, 7 December 2009 through 10 December 2009, Singapore ; 2009 , Pages 1100-1103 ; 9781424428021 (ISBN) ; Shishegar, A. A ; Sharif University of Technology
IEEE
2009
Abstract
In this paper we deal with ray tracing acceleration problem in wave propagation simulation as a separate problem from its computer graphical counterpart and try to review accelerating techniques with this point of view. We build a classical kd-tree adapted to the special geometry of the problem. Then we mention the main differences between these two problems and devise algorithms that use these differences for accelerating intersection test in this problem even further
Application of Axiomatic Design in Appropriate Design Selection
, M.Sc. Thesis Sharif University of Technology ; Houshmand, Mahmoud (Supervisor)
Abstract
Under current competition situation of marketplace, customers’ needs force organizations to make effective decisions about their productions or services. Organizations have to present good products in suitable time and place than their competitors. Indeed customers’ needs effect on making decision about product, service, system or process designs. Problem definition is the most important step in design process. It is possible that, different designers make different designs to satisfy similar requirements because of subjective nature of problem definition. It may results countless design solutions and the best design must be selected among them with considering many criteria. There are many...
Over-complete Dictionary Learning for Sparse Representation
, M.Sc. Thesis Sharif University of Technology ; Babaie-Zadeh, Massoud (Supervisor)
Abstract
Sparse representation has been an important problem in recent decade. The main idea in this problem is that natural signals have information contents much lower than their ambient dimensions and as such, they can be represented by using only a few atoms. For example, if the dimension of signal is n, the purpose in sparse representation is to achieve the representation of signal in terms of s atom (s ≪ n). In sparse coding, the dictionary depends on the used signal. In some of the problem, dictionary is specified and sparse representation is obtained by this dictionary. In this case, because the dictionary is known, maybe sparse representation is not suitable for this signal. For this reason,...
Towards a goal-driven method for web service choreography validation
, Article 2016 2nd International Conference on Web Research, ICWR 2016, 27 April 2016 through 28 April 2016 ; 2016 , Pages 66-71 ; 9781509021666 (ISBN) ; Ebrahimifard, A ; Amiri, M. J ; Khoramabadi Arani, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2016
Abstract
Nowadays web services composition that presents capabilities in response to customers' complex requirements has a special importance in real businesses. However, service choreography as a form of service composition, still faces many challenges. One of the most important challenges of the choreography domain is how to validate the model based on the corresponding requirements. To this end, in this paper processes choreographies are modeled using the interaction view of BPMN 2.0 standard. Then, goal modeling is suggested to extract the requirements. For each requirement all possible valid scenarios are considered and finally using Savara tool, the requirements' scenarios are modeled and the...
Development of simple and efficient Lab-on-a-Disc platforms for automated chemical cell lysis
, Article Scientific Reports ; Volume 10, Issue 1 , 6 July , 2020 ; Saadatmand, M ; Eghbal, M ; Parsa Yeganeh, L ; Sharif University of Technology
Nature Research
2020
Abstract
Cell lysis is the most important first step for molecular biology and diagnostic testing. Recently, microfluidic systems have attracted considerable attention due to advantages associated with automation, integration and miniaturization, especially in resource-limited settings. In this work, novel centrifugal microfluidic platforms with new configurations for chemical cell lysis are presented. The developed systems employ passive form of pneumatic and inertial forces for effective mixing of lysis reagents and cell samples as well as precise fluidic control. Characterizations of the developed Lab-on-a-Discs (LoaDs) have been conducted with dyed deionized (DI) waters and white blood cells...