Sharif Digital Repository

This paper presents a kinematics and workspace analysis of cable-suspended manipulators with elastic cable. The mechanics of extensible cable with a deflection to its selfweight are studied. The problem of evaluating the workspace is approached by using a modified formulation for a deformable cable. The proposed algorithm for testing whether a given configuration lies within the reachable workspace is applied. Starting with a general statement of the kinetic equations of the elastic cable and incorporate cable flexibility into workspace generation. This algorithm is verified through simulation results of various cable-suspended robots. © 2008 IEEE  

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  

An improved wavelet-based 2-D ECG data compression method is presented which employs a double stage compression. In the first stage the set partitioning in hierarchical trees (SPIHT) algorithm is used to compress the 2-D data array formed by cutting and beat-aligning the heartbeat data sequence. In the second stage vector quantization is applied to the residual image obtained from the previous stage. The 2-D approach utilizes both inter-beat and inter-sample redundancies in the ECG signal The proposed algorithm is applied to several records in the MIT-BIH arrhythmia database. Results show lower Percent Root mean square Difference (PRD) than 1-D methods and several 2-D methods for the same... 

Atomic force microscope (AFM) can be used as nanorobotics manipulation tool for nano particle positioning, pushing, indenting, cutting and etc. control the vibration behavior of AFM and make the micro-cantilever tip track specified trajectory is very crucial to appropriately manipulate particles in nano-scales. The novel combined sliding mode approach has been investigated in this paper to obtain robust nonlinear control scheme for nanomanipulation. First (classical) and second order (SOSM) sliding mode techniques have been developed and applied to nonlinear dynamical and uncertain model of AFM cantilever beam to track the desired trajectories. The simulation results show chattering in... 

By the immense growth of the Web-Based Social Networks (WBSNs), the role of trust in connecting people together through WBSNs is getting more important than ever. In other words, since the probability of malicious behavior in WBSNs is increasing, it is necessary to evaluate the reliability of a person before trying to communicate with. Hence, it is desirable to find out how much a person should trust another one in a network. The approach to answer this question is usually called trust inference. In this paper, we propose a new trust inference algorithm (Called RN-Trust) based on the resistive networks concept. The algorithm, in addition to being simple, resolves some problems of previously... 

One of the major problems in liberalized power markets is loss allocation. In this paper, a new method for allocating transmission losses to pool market participants is proposed. The proposed method is fundamentally based on Bialek's "Tracing the flow of electricity" method. The losses is allocated to market participants using the loss weight factors (LWFs) which are obtained from the square current magnitude and Z-bus matrix. The LWF method is based on a solved load flow and strongly emphasizes on current magnitude while considers network topology. The method has been implemented and tested on several networks and one sample summarized in the paper. The results show that the method has an... 

People usually use trust and reputation to cope with uncertainty which exists in the nature and routines. The existing approaches for inferring trust rely on homogeneous relations. In other words, trust is just inferred by a homogeneous relation. In this paper, we present a new model for inferring trust using heterogeneous social networks; we use relation extraction to make a trust relation from the other relation such as friendship and the college relation and then introduced an algorithm to infer trust using extracted relation. In order to get higher performance, we extend relation extraction problem by proposing a genetic algorithm. This algorithm is more scalable, interpretable and... 

One of the services used in mobile phone is the short message service (SMS) which is widely used by the public in all parts of the world especially in Asia and Europe. This service enables people to write and exchange short messages via mobile phone. Due to the limited size of SMS, lack of a proper keyboard on the mobile phone and to improve the speed of typing, new abbreviations have been invented for different words and phrases which has lead to the invention of a new language called SMS-Textlng. One of the main issues in communication is information security and privacy. There are many methods for secret communication and many researchers are working on steganography. In steganography the... 

Invention of the Internet and its spread in the world changes various aspects of human life. In addition, Internet changed human relations. Chat is one of the new aspects which invented after the Internet and is welcomed by users, especially by young people. In chat rooms, people talk with each other using text messages. Because of the need for quick typing of the word and also because of the high amount of sentences which is exchanged between users, new abbreviations are invented for various words and phrases in chat rooms. This new language is known as SMS-Texting. On the other hand, the issue of safety and security of information and especially secret relationships has led to the... 

Taxonomy learning is one of the major steps in ontology learning process. Manual construction of taxonomies is a time-consuming and cumbersome task. Recently many researchers have focused on automatic taxonomy learning, but still quality of generated taxonomies is not satisfactory. In this paper we have proposed a new compound similarity measure. This measure is based on both knowledge poor and knowledge rich approaches to find word similarity. We also used Machine Learning Technique (Neural Network model) for combination of several similarity methods. We have compared our method with simple syntactic similarity measure. Our measure considerably improves the precision and recall of automatic... 

Recombination in the Genetic Algorithm (GA) is supposed to extract the component characteristics from two parents and reassemble them in different combinations - hopefully producing an offspring that has the good characteristics of both parents. Symbiotic Combination is formerly introduced as an alternative for sexual recombination operator to overcome the need of explicit design of recombination operators in GA. This paper presents an optimization algorithm based on using this operator in Tabu Search. The algorithm is benchmarked on two problem sets and is compared with standard genetic algorithm and symbiotic evolutionary adaptation model, showing success rates higher than both cited... 

Sudoku puzzle is a logical game which has recently got very popular. Every day various mass media print these puzzles. As a result these puzzles are a suitable alternative for hidden data transfer. SMS (short message service) is one of the popular mobile-phone services. In this service people can write short messages and send it to each other through mobile phones. In this paper a method has been presented for Steganography (hiding data) in Sudoku puzzles and through SMS. In this method after hiding data in a Sudoku puzzle, the puzzle is sent in a way that it does not attract any attention. Steganography algorithm is based on order of place of numbers 1 through 9 in one of the specified row... 

In this paper, a new algorithm for Sparse Component Analysis (SCA) in the noisy underdetermined case (i.e., with more sources than sensors) is presented. The solution obtained by the proposed algorithm is compared to the minimum l1 -norm solution achieved by Linear Programming (LP). Simulation results show that the proposed algorithm is approximately 10 dB better than the LP method with respect to the quality of the estimated sources. It is due to optimality of our solution (in the MAP sense) for source recovery in noisy underdetermined sparse component analysis in the case of spiky model for sparse sources and Gaussian noise. © 2007 IEEE  

An stochastic version of the classical shortest path problem whereby for each node of a graph, a probability distribution over the set of successor nodes must be chosen so as to reach a certain destination node with minimum expected cost. In this paper, we propose a new algorithm based on Particle Swarm Optimization (PSO) for solving Stochastic Shortest Path Problem (SSPP). The comparison of our algorithm with other algorithms indicates that its performance is suitable even by the less number of iterations. © 2008 Springer-Verlag Berlin Heidelberg  

Haplotype information has become increasingly important in analyzing fine-scale molecular genetics data, Due to the mutated form in human genome; SNPs (Single Nucleotide Polymorphism) are responsible for some genetic diseases. As a consequence, obtaining all SNPs from human populations is one of the primary goals of studies in human genomics. In this paper, a data fusion method based on multiple parallel classifiers for reconstruction of haplotypes from a given sample Single Nucleotide Polymorphism (SNP) is proposed. First, we design a single greedy algorithm for solving haplotype reconstructions. [2] is used as an efficient approach to be combined with first classification method. The... 

Watermarking is the process of hiding information in a media and usually used to for copyright protection. In software watermarking, the information is added to the source code of program and can be extracted from compiled executable code. In this paper, a new software watermarking algorithm is proposed by equation reordering. In this method, the order of operands in an equation is changed according to the information we want to hide in a way that the result of the equation is unchanged. One of the main advantages of this method is that no code added to the program, so the size and speed of the program not changed  

Soccer model and relation of players and coach has been analyzed by a learning automata-based method, called Soccer Mobility Estimator (SME), who estimates the mobility model of soccer players. During a soccer match, players play according to a certain program designed by coach. The pattern of players' mobility is not stochastic and it can be assumed that they are playing with a certain mobility model. Since knowledge about mobility model of nodes in mobile ad-hoc networks has a substantial effect on its performance evaluation, knowledge about mobility model of soccer players can be useful for coaches and experts for game analysis. In fact the mobility model of players could be an important... 

Fast locking PLL-based wide-band frequency synthesizers used in high performance RF transceivers often require multi-band voltage controlled oscillator (VCO). These types of frequency synthesizers employ both discrete and continuous tuning mechanisms to satisfy wide frequency range and low VCO tuning gain simultaneously. To facilitate discrete tuning mechanisms, an auxiliary digital loop is required in order to select proper band of VCO. This digital loop is called adaptive frequency calibration (AFC). In this paper two methods of previous AFC architectures are discussed and improved to gain the minimum possible lock time of PLL. Then, these two methods are simulated and implemented over... 

Now we are able to offer numerous softwares for mobile phones after the advances in mobile phone industry. Most of these softwares should be bought in order that we can use them. Some of these softwares are sharewares and after buying them you have to insert an activation code given by the manufacturing company based on your mobile IMEI code in order to activate the software. In this paper a new method is introduced for sending the mobile software activation code by SMS (Short Message Service). In this method the activation code is hidden in an SMS picture message by steganography method and sent to the user. The software extracting the activation code from the picture and compare it with... 

High availability of software systems is an essential requirement for pervasive computing environments. In such systems self-adaptation, using dynamic reconfiguration is also a key feature. However, dynamic reconfiguration potentially decreases the system availability by making parts of the system temporary frozen, especially during incomplete or faulty execution of the reconfiguration process. In this paper, we propose Assured Dynamic Reconfiguration Framework (ADRF), consisting of run-time analysis phases, assuring the desired correctness and completeness of dynamic reconfiguration process. We also specify factors that affect availability of reconfigurable software in pervasive computing...