Sharif Digital Repository

This paper is aimed at proposing a current based vector control model of the brushless doubly fed induction generator, modelling the presented control method, as well as implementing the proposed algorithm by DSP. In order to achieve the purpose, by presenting a detailed coupled circuit model of BDFIG, the vector model and then the current based vector control algorithm of the mentioned machine are acquired. The way of independent control of torque and power, and also the structure of speed controller amongst the proposed control model are discussed. Additionally, the concepts behind the proposed structure of the speed control system and the way of determining the model parameters are... 

Ambient Intelligence is a new paradigm in information technology that creates environments able to detect and respond to users’ needs, actions, behaviors and feelings. User trust plays an important role in accepting Ambient Intelligence environments. In this paper we describe the design and implementation of a virtual reality based testbed for studying trust in Ambient Intelligence Environments  

New advances in mobile-computer technology, together with the advent of wireless networking, introduce new requirements, capabilities and concerns to the computer science and industry. In this paper, we discuss the special requirements of file sharing in mobile environments. Then our proposed architecture for mobile file sharing (MobFish) is presented. Finally, we present an implementation of the proposed architecture based on its special design tactics. © 2006 by Knowledge Systems Institute Graduate School. All rights reserved  

Electromyogram signal is a biopotential signal that may be measured on the surface of contracting muscles representing neuromuscular activities. This signal may be utilized in various applications such as clinical diagnosis of diseased neuromuscular systems and as a measurement tool for evaluation of rehabilitation activities. Another recent application is the usage of EMG signal in design and implementation of neural controlled prosthesis hands. For this purpose appropriate features of EMG signal are required such that intended hand movements may be recognized correctly. In this work we considered a new method based on quadratic time-frequency representation namely Wigner-Ville distribution... 

Power augmentation is known to be one of the important applications of Exoskeletons. This paper designs a control strategy to reduce the energy consumed by users in power augmentation mode. The strategy aims to calculate and apply the interaction force between humans and robots according to human intentions. To realize human intentions, the movement's kinematic characteristics and the user's muscular activity were used. The movement patterns were learned by the robot using a set of adaptive oscillators. The human movement pattern in each movement cycle was considered the basis for predicting human intention in the next cycle. Thereby, the robot's optimal path and interaction torque were... 

In economic design of profiles, parameters of a profile are determined such that the total implementation cost is minimized. These parameters consist of the number of set points, n, the interval between two successive sampling, h, and the parameters of a control chart used for monitoring. In this paper, the Lorenzen-Vance cost function is extended to model the costs associated with implementing profiles. The in-control and the out-of-control average run lengths, ARL0 and ARL1, respectively, are used as two statistical measures to evaluate the statistical performances of the proposed model. A genetic algorithm (GA) is developed for solving both the economic and the economic-statistical... 

The design and implementation of linear and nonlinear control methods for a three-pole active magnetic bearing (AMB) is presented in this paper. It is shown that the system has nearly linear dynamics by adding a bias to coil currents. A decentralized PID feedback law and an integral sliding mode controller are proposed and the unknown state variables of the system are estimated by the Kalman filter. The optimal gains of the linear controller are determined by the LQG technique. To evaluate the effectiveness of the proposed controllers, they are implemented on an experimental setup. The experimental results show that the proposed methods can effectively stabilize the three-pole AMB. The... 

In this paper, we present and discuss the physical implementation and testing of a Spectrally-Encoded Spread-Time Code Devision Multiple Access (SE/ST-CDMA) transceiver. The proposed design is suitable for multiple-access and anti jamming wireless communication systems. The design and implementation takes into account the ability to automatically detect and mitigate tone jammers by altering the corresponding Gold sequence codes assigned uniquely to each user and setting the corresponding code's chip to zero. A simple real-time anti jamming mechanism capable of dealing with frequency hopping jammers is also proposed. The simulation results are provided in terms of Bit Error Rate (BER) versus... 

A wide range of applications in engineering and scientific computing are based on the sparse matrix computation. There exist a variety of data representations to keep the non-zero elements in sparse matrices, and each representation favors some matrices while not working well for some others. The existing studies tend to process all types of applications, e.g., the most popular application which is matrix–vector multiplication, with different sparse matrix structures using a fixed representation. While Graphics Processing Units (GPUs) have evolved into a very attractive platform for general purpose computations, most of the existing works on sparse matrix–vector multiplication (SpMV, for... 

The design and implementation of the hybrid control method for a three-pole active magnetic bearing (AMB) is proposed in this paper. The system is inherently nonlinear and conventional nonlinear controllers are a little complicated while the proposed hybrid controller has a piecewise linear form, i.e., linear in each sub-region. A state-feedback hybrid controller is designed in this study and the unmeasurable states are estimated by an observer. The gains of the hybrid controller are obtained by the LQR method in each sub-region. To evaluate the performance, the designed controller is implemented on an experimental setup. The experimental results show that the proposed method can efficiently... 

Design and implementation of Architecture is a knowledge-driven process. Evaluation and verification the knowledge, in order to ensure its quality, have important role in improving overall design process. Furthermore, Architectural decision making is a complex and multi-criteria decision making problem in which multiple stakeholders make decisions from their perspectives causing overlaps and conflicts in the adopted decisions. Therefore, the requirement for strategies to manage these issues and also to improve coordination and cooperation among the various stakeholders to improve the overall process design is necessary. In this regard, there have been several activities that focus on... 

A wide range of applications in engineering and scientific computing are based on the sparse matrix computation. There exist a variety of data representations to keep the non-zero elements in sparse matrices, and each representation favors some matrices while not working well for some others. The existing studies tend to process all types of applications, e.g., the most popular application which is matrix–vector multiplication, with different sparse matrix structures using a fixed representation. While Graphics Processing Units (GPUs) have evolved into a very attractive platform for general purpose computations, most of the existing works on sparse matrix–vector multiplication (SpMV, for... 

Successful design and implementation of knowledge management systems have been the main concern of many researchers. It has been reported that more than 50% of knowledge management systems have failed, therefore, it is required to seek for a new and comprehensive scientific approach to design and implement it. In the design and implementation of a knowledge management system, it is required to know 'what we want to achieve' and 'how and by what processes we will achieve it'. A literature review conducted and axiomatic design theory selected for this purpose. For the first time, this paper develops a conceptual design of knowledge management systems by means of a hierarchical structure,... 

Gait training is a critical rehabilitation procedure for patients suffering from walking problems. It, however, puts the therapist in high orthopedic risk since he should prevent the patient from possible falling. Body weight support system is a new technology helping such patients and the involved therapist by unloading a percent of the patient's weight. A new over-ground body weight support is introduced in this article. The system is composed of two main modules namely unloading and traction. The unloading module is capable of suspending an individual's weight up to 1000N dynamically. The whole system is attached to an overhead rail, moving over the head of the patient by the traction... 

Distribution system operators that seek operational excellence are supposed to design and implement capable processes throughout their value stream and assess how well their real services match the design specifications. Process capability analysis is a critical stage in systematic and sophisticated quality engineering approaches such as six sigma, which are based on quantitative studies. The capability of a distribution network to maintain the power quality and voltage level within an acceptable range is one of the most important aspects of design and utilisation of electricity distribution network. Capability analysis has been successfully used in the previous studies to assess the quality... 

Deep neural networks are currently the best solution for road and traffic scene interpretation for autonomous and self-driving vehicles. Compared to the autonomous cars, motorcycles have significant flexibility and advantages in crowded traffic situations and especially in non-urban and off-road areas. Many off-road tracks especially for agriculture and environment management tasks are only traversable with motorcycles. In this paper, a deep neural network is used for design and implementation of the vision system for navigation of an autonomous motorcycle. The proposed framework is evaluated using real world scenarios captured by a real motorcycle in various complex situations. The... 

This paper presents the design and implementation of a bidirectional distributed amplifier (BDDA) in a 0.18- boldsymbol mu ext{m} CMOS process. The performance of the BDDA is theoretically analyzed, and the optimum number of gain stages ( n-{ ext {opt}} ), maximum achievable power gain ( G-{P} ), and circuit bandwidth are formulated. In addition, a new formula for proper choice of the number of DA stages (i.e., n ) is offered where dc-power consumption of the circuit ( P-{ ext {dc}} ) is also considered. This formula optimizes G-{P}/P-{ ext {dc}} , and it is preferred over the conventional n-{ ext {opt}} formula. To validate the theoretical analyses, a 2-12-GHz BDDA with high output 1-dB... 

Social robots may soon be able to play an important role in expanding communication with the deaf. Based on the literature, adaptive user interfaces lead to greater user acceptance and increased teaching efficiency compared to non-adaptive ones. In this paper, we build a robotic architecture able to simultaneously adjust a robot’s teaching parameters according to both the user’s past and present performance, adapt the content of the training, and then implement it on the RASA robot to teach sign language based on these parameters in a manner similar to a human teacher. To do this, a word to teach in sign language, repetition, speed, and emotional valence were chosen to be adaptive using a... 

The technology world is developing fast with the developments made in the hardware and software areas. Considering that privacy and security of telemedicine applications are among the main necessities of this industry, as a result, there is a need to use lightweight and practical algorithms to be used in applications in the field of telemedicine, while security have the least negative impact. The distinct and contradicting components in the design and implementation of the cryptography algorithm, to achieve various objectives in medicine-based applications, have made it a complicated system. It is natural that, without identifying the components, indices, and properties of each system...