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Human Identity Recognition Through Gait and Body Motions Analysis
, M.Sc. Thesis Sharif University of Technology ; Ghaemmaghami, Shahrokh (Supervisor)
Abstract
Among all biometric approaches, gait analysis is one of the most practical methods for human identity recognition. Gait has a lot of advantages over other biometrics like face recognition, iris recognition, fingerprint, etc. First and foremost, the gait data can be collected from a distance, and there is no need for subject’s cooperation. Another advantage of this biometric method is its cost-effectiveness and the fact that it does not need high-resolution images. But there are significant challenges in detecting and analyzing this feature. One of the most important challenges is decreased recognition accuracy caused by identity-irrelevant factors like camera viewpoint and changes in walking...
Analytical structural behaviour of elastic flapping wings under the actuator effect
, Article Aeronautical Journal ; Volume 122, Issue 1254 , 2018 , Pages 1176-1198 ; 00019240 (ISSN) ; Pourtakdoust, S. H ; Bighashdel, A ; Sharif University of Technology
Cambridge University Press
2018
Abstract
The effect of inertial forces on the Structural Dynamics (SD) behaviour of Elastic Flapping Wings (EFWs) is investigated. In this regard, an analytical modal-based SD solution of EFW undergoing a prescribed rigid body motion is initially derived. The formulated initial-value problem is solved analytically to study the EFW structural responses, and sensitivity with respect to EFWs' key parameters. As a case study, a rectangular wing undergoing a prescribed sinusoidal motion is simulated. The analytical solution is derived for the first time and helps towards a conceptual understanding of the overall EFW's SD behaviour and its analysis required in their designs. Specifically, the EFW transient...
On the coupled dynamics of small spacecraft and elastic deployable appendages
, Article Multibody System Dynamics ; 2016 , Pages 1-26 ; 13845640 (ISSN) ; Malaek, S. M ; Abedian, A ; Sharif University of Technology
Springer Netherlands
2016
Abstract
A thorough investigation of the dynamics of finite-mass satellites with a deployable elastic arm is presented. This work is focused on the interaction between spacecraft rigid body motion and its flexible arm dynamics during the deployment process. The classical Newton–Euler formulation and the Lagrangian approach are applied to the study of the dynamics of spacecraft and its deploying arm. Utilizing a non-Newtonian floating frame to define the arm elastic deformation field, the interactions between the spacecraft and its moving arm have been simulated. Complete equations of motion show that the spacecraft motion induces dynamical stiffness on the arm; in addition, axial and lateral motions...
On the coupled dynamics of small spacecraft and elastic deployable appendages
, Article Multibody System Dynamics ; Volume 40, Issue 3 , 2017 , Pages 235-260 ; 13845640 (ISSN) ; Malaek, S. M ; Abedian, A ; Sharif University of Technology
Springer Netherlands
2017
Abstract
A thorough investigation of the dynamics of finite-mass satellites with a deployable elastic arm is presented. This work is focused on the interaction between spacecraft rigid body motion and its flexible arm dynamics during the deployment process. The classical Newton–Euler formulation and the Lagrangian approach are applied to the study of the dynamics of spacecraft and its deploying arm. Utilizing a non-Newtonian floating frame to define the arm elastic deformation field, the interactions between the spacecraft and its moving arm have been simulated. Complete equations of motion show that the spacecraft motion induces dynamical stiffness on the arm; in addition, axial and lateral motions...
Human Action Recognition Using 3D Analysis
, M.Sc. Thesis Sharif University of Technology ; Kasaei, Shohreh (Supervisor)
Abstract
The goal of human action recognition systems is to label the sensory observation data, using one of the predefined action verbs in the system. During recent years, human action recognition has received a growing interest due to its application in automatic scene interpretation. For instance, automatic surveillance systems in public places should be able to discriminate normal and suspicious actions. Human-computer-interface (HCI) systems (which have became popular in recent years) mostly need a similar system to recognize the gesture of their users without using any keyboard (or similar input devices). Human action recognition technologies can also boost the video retrieval systems.
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3D human action recognition using Gaussian processes dynamical models
, Article 2012 6th International Symposium on Telecommunications, IST 2012 ; 2012 , Pages 1179-1183 ; 9781467320733 (ISBN) ; Ghadakchi, V ; Kasaei, S ; Sharif University of Technology
2012
Abstract
An efficient method to automatically recognize basic human actions is proposed to improve the communication between a human and a computer. Human actions are considered as patterns generated by complex non-linear dynamical models. A non-linear dynamical model is used to represent human actions. Gaussian process dynamical models are used to capture the spatial and temporal behaviors of actions. To make the process more efficient a 7-dimensional feature is extracted for each action. Although the extracted feature vector is compact compared to a high-dimensional temporal pattern, it can efficiently discriminate among different actions. The tests run on CMU MoCap database with SVM show promising...
A modified unsteady-nonlinear aeroelastic model for flapping wings
, Article Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering ; 2022 ; 09544100 (ISSN) ; Zare, H ; Bighashdel, A ; Sharif University of Technology
SAGE Publications Ltd
2022
Abstract
A novel integrated aeroelastic model of flapping wings (FWs) undergoing a prescribed rigid body motion is presented. In this respect, the FW nonlinear structural dynamics is enhanced via a newly proposed modification of implicit condensation and expansion (MICE) method that better considers the structural nonlinear effects. In addition, the unsteady aerodynamic model is also an extension of the widely utilized modified strip theory (MST) in which the flexibility effects are accounted for (MST-Flex). The integrated utility of the proposed generalized MICE and MST-Flex is demonstrated to be more realistic for elastic FW flight simulation applications. The prescribed rigid body motion is...
Aeroelastic behavior of a slender body considering free fittings
, Article Journal of Mechanical Science and Technology ; Volume 24, Issue 9 , 2010 , Pages 1755-1762 ; 1738494X (ISSN) ; Haddadpour, H ; Ahmadian, M. T ; Sharif University of Technology
2010
Abstract
This paper presents dynamic and vibration analysis of a flight vehicle with consideration of the free fitting between its two sections. Using the Lagrangian approach, a general analytical model is developed for a non-spinning elastic vehicle in planar motion. The model contains rigid body motions and bending deformations of two sections of the flight vehicle and a nonlinear rotational spring that models the freeplay between the two sections. To express bending deformation, the mode summation method is applied. It is shown that freeplay in the joints significantly affects the trajectory of the flight vehicle. Numerical examples reveal the effect of a joint's nonlinearity on the trajectory and...
A unified computational method for simulating dynamic behavior of planing vessels
, Article China Ocean Engineering ; Volume 23, Issue 3 , 2009 , Pages 517-528 ; 08905487 (ISSN) ; Jahanbakhsh, E ; Panahi, R ; Karimi, M. H ; Sharif University of Technology
2009
Abstract
High speed planing hulls have complex hydrodynamic behaviors. The trim angle and drafts are very sensitive to speed and location of the center of gravity. Therefore, motion simulation for such vessels needs a strong coupling between rigid body motions and hydrodynamic analysis. In addition, free surface should be predicted with good accuracy for each time step. In this paper, velocity and pressure fields are coupled by use of the fractional step method. On the basis of integration of the two-phase viscous flow induced stresses over the hull, acting loads (forces and moments) are calculated. With the strategy of boundary-fitted body-attached mesh and calculation of 6-DoF motions in each time...