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On the design of robotic fish based on lighthill's small-amplitude elongated body theory
, Article 2008 ASME International Mechanical Engineering Congress and Exposition, IMECE 2008, Boston, MA, 31 October 2008 through 6 November 2008 ; Volume 11 , 2009 , Pages 119-125 ; 9780791848722 (ISBN) ; Meghdari, A ; Sharif University of Technology
2009
Abstract
This paper addresses the issues of energy efficiency in robotic fish design by use of hydrodynamic models. The use of LighthilPs small-amplitude elongated body theory for designing of robotic fish, obtaining optimal kinematics and dynamic analysis with emphasis on compliant mechanism is presented. Simulation results for a sample case have demonstrated the importance of proposed approach in robotic fish design. Copyright © 2008 by ASME
Investigation of dynamics and vibration of a three unit pig in oil and gas pipelines
, Article 2008 ASME International Mechanical Engineering Congress and Exposition, IMECE 2008, Boston, MA, 31 October 2008 through 6 November 2008 ; Volume 11 , 2009 , Pages 265-275 ; 9780791848722 (ISBN) ; Fazeli, A ; Azimi, M ; Sharif University of Technology
2009
Abstract
In this paper, the transient motion of a three unit intelligent Pipe Inspection Gauge (PIG) while moving across anomalies and bends inside gas/oil pipeline has been investigated. The pipeline fluid has been considered as isothermal and compressible. In addition, the pipeline itself has also been considered to be flexible. The fluid continuity and momentum equations along with the 3D multi body dynamic equations of motion of the pig comprise a system of coupled dynamic differential equations which have been solved numerically. Pig's position and velocity profiles as well as upstream and downstream fluid's pressure waves are presented as simulation results which provide a better understanding...
Impulsive noise cancellation based on soft decision and recursion
, Article IEEE Transactions on Instrumentation and Measurement ; Volume 58, Issue 8 , 2009 , Pages 2780-2790 ; 00189456 (ISSN) ; Feizi, S ; Amini, A ; Ferdosizadeh, M ; Marvasti, F ; Sharif University of Technology
2009
Abstract
In this paper, we propose a new method to recover band-limited signals corrupted by impulsive noise. The proposed method successively uses adaptive thresholding and soft decisioning to find the locations and amplitudes of the impulses. In our proposed method, after estimating the positions and amplitudes of the additive impulsive noise, an adaptive algorithm, followed by soft decision, is employed to detect and attenuate the impulses. In the next step, by using an iterative method, an approximation of the signal is obtained. This signal approximation is successively used to improve the noise estimate. The algorithm is analyzed and verified by computer simulations. Simulation results confirm...
Modeling and evaluating reliable real-time degree in multi-hop wireless sensor networks
, Article 2009 IEEE Sarnoff Symposium, SARNOFF 2009, Princeton, NJ, 30 March 2009 through 1 April 2009 ; 2009 ; 9781424433827 (ISBN) ; Yousefi, H ; Jahangir, A. H ; IEEE ; Sharif University of Technology
2009
Abstract
Wireless Sensor Network (WSN) should be capable of fulfilling its mission, in a timely manner and without loss of important information. In this paper, we propose a new analytical model for calculating RRT (Reliable Real-Time) degree in multihop WSNs, where RRT degree describes the percentage of real-time data that the network can reliably deliver on time from any source to its destination. Also, packet loss probability is modeled as a function of the probability of link failure when the buffer is full and the probability of node failure when node's energy is depleted. Most of network properties are considered as random variables and a queuing-theory based model is derived. In this model,...
A new adaptive prediction-based tracking scheme for wireless sensor networks
, Article Proceedings of the 7th Annual Communication Networks and Services Research Conference, CNSR 2009, 11 May 2009 through 13 May 2009, Moncton, NB ; 2009 , Pages 335-341 ; 9780769536491 (ISBN) ; Abolhassani, B ; Abdizadeh, M. T ; Sharif University of Technology
2009
Abstract
The accuracy of the object tracking is dependent on the tracking time interval. Smaller tracking time interval increases the accuracy of tracking a moving object. However, this increases the power consumption significantly. This paper proposes a new adaptive algorithm (AEC) to adapt tracking time interval such that it minimizes power consumption while keeping the required accuracy. Simulation results show that using the proposed algorithm, the tracking network has a good performance with the added advantage of reducing the power consumption significantly when compared with existing nonadaptive methods (like PATES). Moreover, simulation results show that the performance of the proposed...
3MOKAN: A novel mobility management mechanism based on keeping alternative nodes
, Article 22nd International Conference on Advanced Information Networking and Applications Workshops/Symposia, AINA 2008, Gino-wan, Okinawa, 25 March 2008 through 28 March 2008 ; 2008 , Pages 756-761 ; 1550445X (ISSN) ; 0769530966 (ISBN); 9780769530963 (ISBN) ; Fazli, E ; Movaghar, A ; Mohammadi, H ; Sharif University of Technology
2008
Abstract
A mobile ad hoc network (MANET) is a network without any predefined infrastructure in which every node not only enjoys the services from the network, but serves the network as a relaying router. Because of nodes mobility, these kinds of networks are highly dynamic. Therefore, link failure is so frequent. In this paper we propose a novel mobility management method which is independent of underlying routing protocol. Based on this mechanism, a node tries to keep an alternate node for its next hop and when a link breakage occurs, simply node uses its alternate node as next hop. Simulation results show that this mechanism can reduce average number of hop counts, number of selected routes and...
Decentralized impedance control of nonredundant multi-manipulator systems
, Article 2008 IEEE International Conference on Networking, Sensing and Control, ICNSC, Sanya, 6 April 2008 through 8 April 2008 ; 2008 , Pages 206-211 ; 9781424416851 (ISBN) ; Ghaffarkhah, A ; Sharif University of Technology
2008
Abstract
In this paper, we propose a decentralized control scheme for combined motion/force control of nonredundant multi-manipulator robotic systems, cooperatively grasping a rigid body in a prespecifled position/force trajectory. The proposed control scheme uses the impedance method for modeling the internal force exerted by the end effectors to the object. The precise mathematical analysis of the overall dynamical system and the proposed controller are presented and the stability of the overall system is studied. The proposed controller, then, is applied to a cooperative system composed of two PUMA560 manipulators and the simulation results are presented to verify the proposed control scheme
Introduction of novel dispatching rules for grid scheduling algorithms
, Article International Conference on Computer and Communication Engineering 2008, ICCCE08: Global Links for Human Development, Kuala Lumpur, 13 May 2008 through 15 May 2008 ; 2008 , Pages 1072-1078 ; 9781424416929 (ISBN) ; Mirza Aghatabar, M ; Khorsandi, S ; Sharif University of Technology
2008
Abstract
Grid scheduling problems are dynamic as the jobs and resources in the system vary overtime. The Rulebased scheduling algorithms are a new trend in grid scheduling which are applicable in dynamic grid environments; The arriving jobs waiting for execution is ordered according to a certain rule and they are dispatched for processing according to that order. Grid scheduling algorithms usually involve more than one objective function. In particular, it is not enough to minimize the Maximum completion time (Makespan) objective function without taking into consideration the lateness of the jobs (Tardiness). In this paper two novel dispatching rules are proposed that aims to minimize the maximum...
Derivation of a vector model for a Brushless Doubly-Fed Machine with multiple loops per nest
, Article 2008 IEEE International Symposium on Industrial Electronics, ISIE 2008, Cambridge, 30 June 2008 through 2 July 2008 ; 2008 , Pages 606-611 ; 1424416655 (ISBN); 9781424416653 (ISBN) ; Oraee, H ; Abdi, E ; McMahon, R ; Sharif University of Technology
2008
Abstract
The paper presents a vector model for a Brushless Doubly-Fed Machine (BDFM). The BDFM has 4 and 8 pole stator windings and a nested-loop rotor cage. The rotor cage has six nests equally spaced around the circumference and each nest comprises three loops. All the rotor loops are short circuited via a common end-ring at one end. The vector model is derived based on the electrical equations of the machine and appropriate vector transformations. In contrast to the stator, there is no three phase circuit in the rotor. Therefore, the vector transformations suitable for three phase circuits can not be utilised for the rotor circuit. A new vector transformation is employed for the rotor circuit...
An asymmetric checkpointing and rollback error recovery scheme for embedded processors
, Article 23rd IEEE International Symposium on Defect and Fault Tolerance in VLSI Systems, DFT 2008, Boston, MA, 1 October 2008 through 3 October 2008 ; October , 2008 , Pages 445-453 ; 15505774 (ISSN) ; Miremadi, S. G ; Ejlali, A ; Sharif University of Technology
2008
Abstract
This paper presents a checkpointing scheme for rollback error recovery, called Asymmetric Checkpointing and Rollback Recovery (ACRR) which stores the processor states in an asymmetric manner. In this way, error recovery latency and the number of checkpoints are reduced to increase the probability of timely task completion for soft real-time applications. To evaluate the ACRR, this scheme was studied analytically. The analytical results show that the recovery latency is reduced as non-uniformity of the checkpoint increases. As a case study, the ACRR is implemented and simulated on a behavioral VHDL model of LEON2 processor. The simulation results follow the results obtained in the analytical...
Salt and pepper noise removal for image signals
, Article 2008 International Conference on Telecommunications, ICT, St. Petersburg, 16 June 2008 through 19 June 2008 ; October , 2008 ; 9781424420360 (ISBN) ; Zahedpour, S ; Soltanolkotabi, M ; Amini, A ; Marvasti, F ; Sharif University of Technology
2008
Abstract
In this paper we propose a new method to recover images corrupted with salt and pepper noise. The proposed method uses ordered statistics filtering and soft-decisioning in successive approximations to find the locations and amplitudes of all the impulses. In our method we use soft-decision to generate a mask which is based on histogram distributions in local windows to distinguish impulsive noise from legitimate pixels. This mask is used to obtain an estimate of the original image by an iterative method. The result of the aforementioned algorithm can be fed back into the system to improve the image reconstruction process. This algorithm is analyzed and verified by simulation results....
Noncoherent integration of UWB radar signals using the hough transform
, Article 2008 5th European Radar Conference, EuRAD 2008, Amsterdam, 30 October 2008 through 31 October 2008 ; 2008 , Pages 9-12 ; 9782874870095 (ISBN) ; Moqiseh, A ; Gheidi, H ; Nayebi, M. M ; Sharif University of Technology
2008
Abstract
Inherent properties of UWB signals prevent both coherent and noncoherent processing with conventional methods used in narrow-band RADARs. In this paper, we show how to exploit the Hough transform, first developed to detect lines in an image distorted by noise, to detect moving objects from successive scans that are corrupted by noise and clutter. We discuss why conventional methods fail to process UWB pulses noncoherently/coherently and investigate different aspects of using the Hough transform in noncoherent integration of UWB signals. Simulation results to support our approach are also presented. © 2008 EuMA
A novel zero-aware read-static-noise-margin-free SRAM Cell for high density and high speed cache application
, Article 2008 9th International Conference on Solid-State and Integrated-Circuit Technology, ICSICT 2008, Beijing, 20 October 2008 through 23 October 2008 ; 2008 , Pages 876-879 ; 9781424421855 (ISBN) ; Manzuri Shalmani, M. T ; Noormandi, R ; Mehrparvar, A ; Sharif University of Technology
2008
Abstract
To help overcome limits to the density and speed of conventional SRAMs, we have developed a five-transistor SRAM cell. The newly developed CMOS five-transistor SRAM cell uses one word-line and one bit-line during read/write operation. This cell retains its data with leakage current and positive feedback without refresh cycle. The new cell size is 18% smaller than a conventional six-transistor SRAM cell using same design rules. Simulation result in standard 0.25μm CMOS technology shows purposed cell has correct operation during read/write and idle mode. The average delay of new cell is 20% smaller than a six-transistor SRAM cell. © 2008 IEEE
A hybrid fuzzy adaptive tracking algorithm for maneuvering targets
, Article 2008 IEEE International Conference on Fuzzy Systems, FUZZ 2008, Hong Kong, 1 June 2008 through 6 June 2008 ; 2008 , Pages 1869-1873 ; 10987584 (ISSN) ; 9781424418190 (ISBN) ; Sadati, N ; Sharif University of Technology
2008
Abstract
A new hybrid fuzzy adaptive algorithm for tracking maneuvering targets is proposed in this paper. The algorithm is implemented with fuzzy inference system (FIS) and current statistical model and adaptive Altering (CSMAF). The CSMAF algorithm is one of most effective methods for tracking the maneuvering targets. It has a higher precision in tracking the maneuvering targets with larger accelerations while it has a lower precision in tracking the maneuvering targets with smaller acceleration. In the proposed algorithm, to overcome the disadvantage of the CSMAF algorithm, the covariance of process noise CSMAF is adjusted adaptively by the output of a FIS. The input of the FIS is discrepancy of...
Emotional learning based intelligent controller for a PWR nuclear reactor core during load following operation
, Article Annals of Nuclear Energy ; Volume 35, Issue 11 , 2008 , Pages 2051-2058 ; 03064549 (ISSN) ; Boroushaki, M ; Lucas, C ; Sharif University of Technology
2008
Abstract
The design and evaluation of a novel approach to reactor core power control based on emotional learning is described. The controller includes a neuro-fuzzy system with power error and its derivative as inputs. A fuzzy critic evaluates the present situation, and provides the emotional signal (stress). The controller modifies its characteristics so that the critic's stress is reduced. Simulation results show that the controller has good convergence and performance robustness characteristics over a wide range of operational parameters. © 2008 Elsevier Ltd. All rights reserved
Investigation of wagon derailment moving on random rail irregularities Using nonlinear 3-dimentional model
, Article International Journal of Engineering, Transactions B: Applications ; Volume 21, Issue 4 , 2008 , Pages 385-400 ; 1728-144X (ISSN) ; Jalili, M. M ; Sharif University of Technology
Materials and Energy Research Center
2008
Abstract
Rail irregularity is one of the most effective factors in train derailment. theste irregularities have generally random distribution that are assumed to be stationary random and ergodic processes in space, with Gaussian amplitude probabiliy densities and zero mean values. The quality of irregularities, their distribution along the rails and wagon speed are the main factors for train derailment which is investigated in this article. The car model is nonlinear and three-dimensional with 48 DOF. Using simulation results, the safe speed for moving wagon on different types of random rail irregularities is also determined
Two techniques for audio watermarking based on a novel transformation
, Article 2007 IEEE International Conference on Signal Processing and Communications, ICSPC 2007, Dubai, 14 November 2007 through 27 November 2007 ; 2007 , Pages 1139-1142 ; 9781424412365 (ISBN) ; Akhaee, M. A ; Marvasti, F ; Sharif University of Technology
2007
Abstract
The main purpose of this paper is to embed data in the transform domain of audio signals. Data embedding is similar to Quantization Index Modulation (QIM) approach. But the embedding process is performed in a novel transformation named PPG (Point to Point Graph) which converts the audio signal to a set of points in the Cartesian Coordinates. Two watermarking schemes are proposed in this paper. The first approach uses the QIM method on the radius of the PPG points while the second approach employs the logical operand for this aim. Simulation results show that these two methods have great robustness against the common attack (such as White Gaussian noise, echo and filtering). Subjective...
Separation of speech sources in under-determined case using SCA and time-frequency methods
, Article 2008 International Symposium on Telecommunications, IST 2008, Tehran, 27 August 2008 through 28 August 2008 ; 2008 , Pages 533-538 ; 9781424427512 (ISBN) ; Babaiezadeh, M ; Jutten, C ; Sharif University of Technology
2008
Abstract
This paper presents a new algorithm for Blind Source Separation (BSS) of Instantaneous speech mixtures in under-determined case. A demixing algorithm which exploits the sparsity of speech signals in the short time Fourier transform (STFT) domain is proposed. This algorithm combines the modified k-means clustering procedure involved in the Line Orientation Separation Technique (LOST) with Smoothed l0-norm minimization (SL0) method. First procedure along with a transformation into a sparse domain tries to estimate the mixing matrix, and the second method tries to extract the sources from the mixtures. Simulation results are presented and compared to the Degenerate Unmixing Estimation Technique...
A learning automata-based method for estimating the mobility model of nodes in Mobile Ad-hoc Networks
, Article 7th IEEE International Conference on Cognitive Informatics, ICCI 2008, Stanford University, CA, 14 August 2008 through 16 August 2008 ; 2008 , Pages 249-254 ; 9781424425389 (ISBN) ; Iraji, R ; Manzuri Shalmani, M. T ; Sharif University of Technology
2008
Abstract
The mobility model of typical Mobile Ad-hoc NETworks (MANET) can be used for more efficient performance evaluation of such networks. There are a large number of researches for generating various mobility models to use in performance evaluation of mobile ad-hoc networks and also on performance evaluation itself of these networks. But in most of these researches the mobility model of MANET is predefined and based on this mobility model, the performance evaluation goes on. Since in real world applications the mobility model of MANETs is unknown or may be changed during the time, the need for a method of detecting or estimating the MANET's mobility model is evident. In this paper a learning...
Wavelet-based unbalanced un-equivalent multiple description coding for P2P networks
, Article 2007 IEEE International Conference on Telecommunications and Malaysia International Conference on Communications, ICT-MICC 2007, Penang, 14 May 2007 through 17 May 2007 ; February , 2007 , Pages 242-247 ; 1424410940 (ISBN); 9781424410941 (ISBN) ; Ronasi, K ; Pakravan, M. R ; Nasiri Avanaki, A ; Sharif University of Technology
2007
Abstract
Almost all existing multi-description coding (MDC) schemes are designed for media streaming over Internet. In this work, a wavelet-based video MDC technique is introduced that fits the criteria of media streaming over peer-to-peer networks. Our proposed method assigns descriptions to the senders due to their characteristic (i.e. bandwidth and availability). In contrast to traditional MDC, different descriptions in the proposed method have different importance in remaking the original media. Our simulation results show considerable improvement of video quality at the receiver (up to 10 dB) as compared to the state-of-the-art. ©2007 IEEE