Loading...
Search for:
amiri-atashgah--m--a
0.166 seconds
Total 27045 records
An integrated virtual environment for feasibility studies and implementation of aerial MonoSLAM
, Article Virtual Reality ; Volume 16, Issue 3 , September , 2012 , Pages 215-232 ; 13594338 (ISSN) ; Malaek, S. M. B ; Sharif University of Technology
2012
Abstract
This work presents a complete framework of an integrated aerial virtual environment (IAVE), which could effectively help implementing MonoSLAM (single-camera simultaneous localization and mapping) on an aerial vehicle. The developed system allows investigating different flight conditions without using any preloaded maps or predefined features. A 3D graphical engine integrated with a full 6 DOF aircraft dynamic simulator together with its trajectory generator completes the package. The 3D engine generates and accumulates real-time images of a general camera installed on the aerial vehicle. We effectively exploit C++ to develop the 3D graphics engine (3DGE) and all its associated visual...
A simulation environment for path and image generation in an aerial single-camera vision system
, Article Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering ; Volume 225, Issue 5 , 2011 , Pages 541-558 ; 09544100 (ISSN) ; Malaek, S. M. B ; Sharif University of Technology
2011
Abstract
This work describes the essential tools and architecture of a simulation environment, which could help enhance general aviation training as well as safety issues, especially while dealing with flights over unfamiliar environments. It also describes how the authors could effectively generate any desired flight path and its associated surrounding images through implementing a virtual single camera with simultaneous localization and mapping (monocular simultaneous localization and mapping) techniques. The overall package enjoys an aerial three-dimensional (3D)/graphical engine integrated with a full six-degrees-of-freedom aircraft dynamics, which serves as its trajectory generator, together...
Aerial Vision-Based Navigation and Monitoring in Special Conditions
, Ph.D. Dissertation Sharif University of Technology ; Malaek, Mohammad Bagher (Supervisor)
Abstract
This research is dedicated to specific issues in the field of Aerial Vision Based Navigation (VBN). It focuses mainly on vehicles with no pilot such as RPVs and small aircraft; having in mind their safety which must be close to commercial applications. Various methods have been studied and the simplest one; which is based on observation, identification and utilization of landmarks is selected for detailed implementation. In this work, we concentrate on using a single-camera while flying in an unknown environment (MonoSLAM). Other available sensors are accelerometer and GPS receiver to keep the cost down. Different studies show that using a low-cost single camera system is much more efficient...
Integration of image de-blurring in an aerial Mono-SLAM
, Article Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering ; Vol. 228, issue. 8 , May , 2014 , p. 1348-1362 ; Gholampour, P ; Malaek, S. M. B ; Sharif University of Technology
2014
Abstract
In this article, we discuss the possibility of integrating image de-blurring techniques in an aerial simultaneous localization and mapping by a single camera (monocular simultaneous localization and mapping (Mono-SLAM)). We use an integrated aerial virtual environment together with a six-degree-of-freedom aircraft flight simulator to show the effectiveness of the approach to generate three-dimensional flight trajectories via integration of image de-blurring in the associated loop of the Mono-SLAM. The objective is to increase the overall performance of a flying mission over an unknown area by means of a vision-only method. The integrated aerial virtual environment produces and collects...
Prediction of aerial-image motion blurs due to the flying vehicle dynamics and camera characteristics in a virtual environment
, Article Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering ; Volume 227, Issue 7 , 2013 , Pages 1055-1067 ; 09544100 (ISSN) ; Malaek, S. M. B ; Sharif University of Technology
2013
Abstract
This study presents comprehensive studies on practical means to predict aerial-image motion blurs due to the flying vehicle dynamics, including flying altitude; cruising speed; and angular velocities and finally installed camera characteristics; such as, frame rate and image size. The resulting predictions of blur values are in-turn used to generate blurry images to be fed as input data for later use in a de-blurring-in-the-loop of a Mono-simultaneous localization and mapping system. The whole process is coordinated by means of an integrated aerial virtual environment. The integrated aerial virtual environment consists of a three-dimensional graphical engine which could communicate with a...
PBN-Based time-optimal terminal air traffic control using cellular automata
, Article IEEE Transactions on Aerospace and Electronic Systems ; Volume 57, Issue 3 , 2021 , Pages 1513-1523 ; 00189251 (ISSN) ; Amiri Atashgah, M. A ; Malaek, S. M. B ; Thulasiraman, P ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2021
Abstract
Over the last decade, there has been an increase in air transportation, which has raised awareness to provide necessary procedures to respond to air transportation demands and reduce delay costs. One such procedure, 'performance-based navigation (PBN),' currently studied, is expected to increase the airspace capacity based on aircraft's individual performances. This research describes an efficient and expandable model for allocating standard terminal arrival route during continuous descent approach (CDA) that effectively uses PBN requirements. As a case study, we have considered the 'Atlanta International Airport' and verified the model's accuracy using real-time traffic data. The model is...
A secure and efficient chaotic maps based authenticated key-exchange protocol for smart grid
, Article Wireless Personal Communications ; Volume 97, Issue 2 , 2017 , Pages 2551-2579 ; 09296212 (ISSN) ; Beheshti Atashgah, M ; Aref, M. R ; Sharif University of Technology
2017
Abstract
Nicanfar and Leung proposed a multilayer consensus elliptic curve based password authenticated key-exchange (MCEPAK) protocol for smart grid. They claimed that their protocol is secure against possible attacks. In this paper, we show that the MCEPAK protocol is vulnerable to the dictionary attack and an adversary can obtain the passwords of the appliances by eavesdropping the communicated messages in the protocol. Moreover, we state that the passwords can be discovered by curious operators of the building area networks and the neighbor area networks. Theses weaknesses motivated us to introduce a chaotic maps based authenticated key exchange protocol for smart grid. To the best of our...
Improvement on Q. Xie threshold proxy signature scheme against collusion attack
, Article 2011 19th Iranian Conference on Electrical Engineering, ICEE 2011, 17 May 2011 through 19 May 2011 ; May , 2011 , Page(s): 1 - 5 ; ISSN : 21647054 ; 9789644634284 (ISBN) ; Bayat, M ; Gardeshi, M ; Aref, M. R ; Sharif University of Technology
2011
Abstract
In a (t, n) threshold proxy signature scheme, the original signer can delegate the signing power to n proxy signers such that any t or more out of n proxy signers can sign messages on behalf of the original signer, but t -1 or less of the proxy signers cannot generate a proxy signature. In this paper, we will improve the security of Xie's threshold proxy signature scheme against the new types of collusion attack was presented by Liu and Tan in 2007 We also present that our improved scheme is more efficient than Xie's scheme in terms of computational complexities
A novel lattice-based proxy signature scheme
, Article ICEE 2012 - 20th Iranian Conference on Electrical Engineering, 15 May 2012 through 17 May 2012 ; May , 2012 , Pages 1224-1227 ; 9781467311489 (ISBN) ; Ajori, M ; Gardeshi, M ; Aref, M. R ; Sharif University of Technology
2012
Abstract
In a proxy signature scheme, an original signer delegates his/her signing capability to a proxy signer and then the proxy signer can sign messages on behalf of the original signer. The security of many proxy signature schemes that have been proposed depends, either directly or indirectly, on either the difficulty of big integers factoring problem or the difficulty of finding discrete logarithm in a finite group. These types of schemes cannot resist quantum attacks. In this paper, we propose a new lattice-based proxy signature scheme which can resist quantum attacks. The proposed scheme is based on the GGH-signature scheme and also satisfies all the security requirements of proxy signature...
ID-based strong designated verifier signature scheme and its applications in internet of things
, Article 27th Iranian Conference on Electrical Engineering, ICEE 2019, 30 April 2019 through 2 May 2019 ; 2019 , Pages 1486-1491 ; 9781728115085 (ISBN) ; Aref, M. R ; Bayat, M ; Barari, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
Strong designated verifier signature scheme is a concept in which a user (signer) can issue a digital signature for a special receiver; i.e. signature is produced in such way that only intended verifier can check the validity of produced signature. Of course, this type of signature scheme should be such that no third party is able to validate the signature. In other words, the related designated verifier cannot assign the issued signature to another third party. This article proposes a new ID-based strong designated verifier signature scheme which has provable security in the ROM (Random Oracle Model) and BDH assumption. The proposed scheme satisfies the all security requirements of an...
An ultra-lightweight RFID mutual authentication protocol
, Article 16th International ISC (Iranian Society of Cryptology) Conference on Information Security and Cryptology, ISCISC 2019, 28 August 2019 through 29 August 2019 ; 2019 , Pages 27-32 ; 9781728143736 (ISBN) ; Beheshti Atashgah, M ; Eghlidos, T ; Aref, M. R ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
In some applications of the Internet of Things (IoT), for privacy preserving and authentication of entities, it is necessary to use ultra-lightweight cryptographic algorithms. In this paper, we propose a new ultra-lightweight authentication protocol between RFID components, in which only simple operations are used. In this protocol, the server has access to the data gathered by the tag in the same authentication phase through the reader interface, instead of sharing a secret key. The proposed protocol is secure against several attacks, such as replay attacks, denial of service, offline guessing attacks, modification attacks, full disclosure attacks and impersonation attacks, in addition to...
A lightweight anonymous authentication protocol for IoT wireless sensor networks
, Article 16th International ISC (Iranian Society of Cryptology) Conference on Information Security and Cryptology, ISCISC 2019, 28 August 2019 through 29 August 2019 ; 2019 , Pages 39-44 ; 9781728143736 (ISBN) ; Beheshti Atashgah, M ; Eghlidos, T ; Aref, M. R ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
Lightweight authentication protocols are crucial for privacy preserving in Internet of Things (IoT). Authentication protocols should be implementable for devices with constrained memory and computational power in this area, in addition to resistance against cryptographic threats. On the other hand, these protocols should not impose a heavy computational load on such devices. In this paper we proposed an authentication protocol that properly meets these features. Our protocol is suitable for wireless sensor networks (WSNs). In this protocol, authentication is fulfilled with low communication and computational loads between sensors and users through the gateway interface using a hash function...
A sequential approach for hybridizing conventional vehicles and an approval example
, Article 8th Biennial ASME Conference on Engineering Systems Design and Analysis, ESDA2006, Torino, 4 July 2006 through 7 July 2006 ; Volume 2006 , 2006 ; 0791837793 (ISBN); 9780791837795 (ISBN) ; Khanipour, A ; Nabi, A ; Fazeli, A. M ; Amiri, M ; Sharif University of Technology
American Society of Mechanical Engineers
2006
Abstract
Hybridization of conventional vehicles is considered an important step to achieve high fuel economy and low emissions. In this study, principle considerations involved in a hybridizing process are discussed and consequently, a sequential approach for designing hybrid components for both series and parallel configurations has been introduced. The so called approach has then been applied to one of the productions of Iran-Khodro Company called SAMAND. Having designed the hybrid components, the conventional SAMAND and its series and parallel hybrid configurations were defined and evaluated using the ADvanced VehIcle SimulatOR (ADVISOR) software. It is observed that compared to the conventional...
Effects of diverging angle and fuel molecular weight on NOx emissions in converging and diverging ducts
, Article Journal of Engineering Research ; Volume 1, Issue 3 , 2013 , Pages 161-179 ; 23071885 (ISSN) ; Amiri, M ; Amiri, A ; Sharif University of Technology
2013
Abstract
The present paper developed and validated a numerical procedure for the calculation of turbulent combustive flows in converging and diverging ducts. Through simulation of the heat transfer processes, the amounts of production and spread of NOx pollutants were measured. Also, this paper reported the results of a numerical investigation of the effects of the fuel Molecular Weight on NOx emissions in converging and diverging ducts. The fuels which were examined were methane, naphtha, and kerosene. The differential equations in the Von-Misses coordinate system were transformed to a cross-stream coordinate system in order to concentrate more grid lines near wall boundaries. A marching integration...
Phase-field simulation of counter-current spontaneous imbibition in a fractured heterogeneous porous medium
, Article Physics of Fluids ; Volume 29, Issue 6 , 2017 ; 10706631 (ISSN) ; Akhlaghi Amiri, A ; Sharif University of Technology
American Institute of Physics Inc
2017
Abstract
Spontaneous imbibition is well-known to be one of the most effective processes of oil recovery in fractured reservoirs. However, the detailed pore-scale mechanisms of the counter-current imbibition process and the effects of different fluid/rock parameters on this phenomenon have not yet been deeply addressed. Thiswork presents the results of a newpore-level numerical study of counter-current spontaneous imbibition, using coupled Cahn-Hilliard phase field and Navier-Stokes equations, solved by a finite element method. A 2D fractured medium was constructed consisting of a nonhomogeneous porous matrix, in which the grains were represented by an equilateral triangular array of circles with...
A simple method for pulse repetition interval estimation and tracking radar pulse trains with complex pulse repetition interval modulations
, Article Advanced Science Letters ; Volume 19, Issue 8 , 2013 , Pages 2262-2265 ; 19366612 (ISSN) ; Keshavarzi, M ; Amiri, K ; Sharif University of Technology
2013
Abstract
In an electronic warfare environment, an electronic support system receives signals emitted by different radars. One of the key tasks in an electronic support system is PRI estimation tracking Pulse Trains using Pulse Repetition Interval (PRI) of these signals. In this paper we present a simple method for PRI estimation and tracking radar pulse trains with complex PRI Modulations. This method uses nonlinear least square, Pisarenko and innovative methods for PRI estimation and tracking pulse train. Simulation results show high robustness of the proposed method against noise (spurious and missing pulses)
Steady flow quality assessment of a modified transonic wind tunnel
, Article Scientia Iranica ; Volume 20, Issue 3 , 2013 , Pages 500-507 ; 10263098 (ISSN) ; Soltani, M. R ; Haghiri, A ; Sharif University of Technology
2013
Abstract
An existing operational trisonic wind tunnel is upgraded to improve its performance criterion in the transonic regime. In this research, the test section is modified according to the operational requirements of the various existing transonic wind tunnels. Several perforated walls are designed, manufactured, and installed on the top and bottom sides of the test section. The flow in the test section of the wind tunnel is surveyed for the empty condition prior to testing models. Once satisfactory results regarding the flow quality requirements in the test section under various conditions were achieved, a 2D model, NACA 0012, and a 3D standard model for the transonic wind tunnels, AGARD-B, are...
Pulse repetition interval detection using statistical modeling
, Article ACM International Conference Proceeding Series, 21 November 2016 through 24 November 2016 ; Volume Part F125833 , 2016 , Pages 100-104 ; 9781450347907 (ISBN) ; Pezeshk, A. M ; Sharif University of Technology
Association for Computing Machinery
2016
Abstract
Pulse Repetition Interval (PRI) Modulation Detection is an important subsystem of a typical electronic warfare support system. In this paper, a robust, fast, and well designed structure for detection of simple and complex PRI modulations based on statistical and sequential analysis of Pulse Repetition Interval (PRI) is proposed. Accuracy and robustness of the technique against electromagnetic noise are demonstrated via simulations
Energy absorption of friction stir welded 1050 aluminum sheets through wedge tearing
, Article Materials and Design ; Volume 93 , 2016 , Pages 216-223 ; 02641275 (ISSN) ; Kazeminezhad, M ; Kokabi, A. H ; Sharif University of Technology
Elsevier Ltd
2016
Abstract
In this research, 1050 aluminum alloy sheets were welded through Friction Stir Welding technique at different rotational speeds (ω) and advance rates (V) in order to investigate the effects of welding parameters on the energy absorption. Wedge tearing test was then conducted on the specimens in two directions of 0 and 90 degrees relative to the weld line. Energy absorption was revealed to be much higher in the welded specimens in comparison with the non-welded sheets. This increase in the amount of absorbed energy is due to the fine equiaxed grain structure formed in the stir zone of the weld which increases the strength. It was also concluded that when movement of the wedge is parallel to...
Pore-level influence of wettability on counter-current spontaneous imbibition
, Article 79th EAGE Conference and Exhibition 20172017 ; 2017 ; 9789462822177 (ISBN) ; Akhlaghi Amiri, H. A ; Sharif University of Technology
2017
Abstract
Medium wettability plays the main role during spontaneous imbibition (SI) in fractured porous media; however, one can rarely find pore-scale studies addressing wettability effects on this process. In present work Cahn-Hilliard phase field coupled with Navier-Stokes equations were solved using finite element method to simulate counter-current SI in a horizontal heterogeneous porous medium containing fracture. Capillary governed fluid displacement in media with different contact angles - ?=p/10 (extremely water-wet) up to ?=p/2 (neutral wet) - were simulated. The simulated models realistically captured micro-scale mechanisms during imbibition process in strongly water wet media, e.g., oil film...