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intelligent-systems
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Total 207 records
Hydrodynamics Modeling and Self Orginizing Control of Marine Vehicles
, M.Sc. Thesis Sharif University of Technology ; Sayyadi, Hassan (Supervisor)
Abstract
Dynamic positioning system is a controller system used to maintain the position and heading of a vessel with no use of anchors, jack ups but only using the propellers installed on the vessel. A vessel has six degrees of freedom, including three rotations and three transfer. In dynamic positioning systems, the vessel is controlled only on the horizontal plane such that its position and heading are controlled according to predetermined values. To achieve this, position and heading of the vessel is determined and the controller system computes the direction and required power of each propeller. Preliminary systems utilized PID controllers. As the control science has advanced, model based...
Designing an Intelligent Heart Disease Prediction System Via Data Mining Techniques
, M.Sc. Thesis Sharif University of Technology ; Shavandi, Hassan (Supervisor)
Abstract
The healthcare industry collects huge amounts of healthcare data which, unfortunately, are not“mined” to discover hidden information for effective decision making. Discovery of hidden patterns and relationships often goes nexploited. Advanced data mining techniques can help remedy this situation. The diagnosis of diseases is a vital and intricate job in medicine. The recognition of heart disease from diverse features or signs is a multi-layered problem that is not free from false assumptions and is frequently accompanied by impulsive effects. Thus the attempt to exploit knowledge and experience of several specialists and clinical screening data of patients composed in databases to assist the...
Design and Implementation of an Intelligent Analyzer for Hand Rehabilitation
, Ph.D. Dissertation Sharif University of Technology ; Saadat Foumani, Mahmoud (Supervisor) ; Behzadipour, Saeed (Supervisor)
Abstract
In recent years there have been a growing number of patients who are no more capable of leading an independent life, due to strokes, accident, or a variety of diseases. Thus, vast fields of physical rehabilitation have come into the attention of goverments and researchers. High costs of rehabilitation programs and their length on one hand, and the difficulties of commuting such patients to rehabilitation centers on the other hand, has made health department of various countries to look for alternative solutions.In this thesis, a computerized system has been designed and implemented in order to assess and guide patients in their rehabilitation excercises without needing any direct contact....
A low-power low-offset dynamic comparator for analog to digital converters
, Article Microelectronics Journal ; Vol. 45, issue. 2 , February , 2014 , pp. 256-262 ; ISSN: 00262692 ; Zamani, M ; Sharifkhani, M ; Sharif University of Technology
Abstract
A comparator comprises a cross coupled circuit which produces a positive feedback. In conventional comparators, the mismatch between the cross coupled circuits determines the trade-off between the speed, offset and the power consumption of the comparator. A new low-offset low-power dynamic comparator for analog-to-digital converters is introduced. The comparator benefits from two stages and two operational phases to reduce the offset voltage caused by the mismatch effect inside the positive feedback circuit. Rigorous statistical analysis yields the input referred offset voltage and the delay of the comparator based on the circuit random parameters. The derivations are verified with...
Integration of adaptive neuro-fuzzy inference system, neural networks and geostatistical methods for fracture density modeling
, Article Oil and Gas Science and Technology ; Vol. 69, issue. 7 , 2014 , pp. 1143-1154 ; ISSN: 12944475 ; Kadkhodaie-Ilkhchi, A ; Sharghi, Y ; Ghaedi, M ; Sharif University of Technology
Abstract
Image logs provide useful information for fracture study in naturally fractured reservoir. Fracture dip, azimuth, aperture and fracture density can be obtained from image logs and have great importance in naturally fractured reservoir characterization. Imaging all fractured parts of hydrocarbon reservoirs and interpreting the results is expensive and time consuming. In this study, an improved method to make a quantitative correlation between fracture densities obtained from image logs and conventional well log data by integration of different artificial intelligence systems was proposed. The proposed method combines the results of Adaptive Neuro-Fuzzy Inference System (ANFIS) and Neural...
Identifying the tool-tissue force in robotic laparoscopic surgery using neuro-evolutionary fuzzy systems and a synchronous self-learning hyper level supervisor
, Article Applied Soft Computing Journal ; Vol. 14, issue. PART A , January , 2014 , pp. 12-30 ; Behzadipour, S ; Kohani, M ; Sharif University of Technology
Abstract
In this paper, two different hybrid intelligent systems are applied to develop practical soft identifiers for modeling the tool-tissue force as well as the resulted maximum local stress in laparoscopic surgery. To conduct the system identification process, a 2D model of an in vivo porcine liver was built for different probing tasks. Based on the simulation, three different geometric features, i.e. maximum deformation angle, maximum deformation depth and width of displacement constraint of the reconstructed shape of the deformed body are extracted. Thereafter, two different fuzzy inference paradigms are proposed for the identification task. The first identifier is an adaptive co-evolutionary...
Statistical analysis of read static noise margin for near/sub-threshold SRAM cell
, Article IEEE Transactions on Circuits and Systems I: Regular Papers ; Vol. 61, Issue. 12 , November , 2014 , pp. 3386-3393 ; ISSN: 15498328 ; Sharifkhani, M ; Hajsadeghi, K ; Sharif University of Technology
Abstract
A fast statistical method for the analysis of the Read SNM of a 6 T SRAM cell in near/subthreshold region is proposed. The method is based on the nonlinear behavior of the cell. DIBL and body effects are thoroughly considered in the derivation of an accurate closed form solution for the Read Static Noise Margin (SNM) of the near/subthreshold SRAM cell. This method uses the state space equation to derive the Read SNM of the cell as a function of threshold voltage of cell transistors. This function shows the dependency of the Read SNM on sizing, VDD, temperature, and threshold voltage variations. It provides a fast reliability analysis for a cell array of a given size and a supply voltage. It...
A particle swarm optimization approach for robust unit commitment with significant vehicle to grid penetration
, Article Iranian Conference on Intelligent Systems, ICIS 2014 ; 2014 ; Aien, M ; Rashidinejad, M ; Fotuhi-Firouzabad, M
Abstract
Smartening of contemporaneous power delivery systems in conjunction with increased penetration of vehicle to grid (V2G) technology, changes the way market participants play their role in the market operation to maximize their profit. In V2G technology, plug-in electric vehicles (PEV) have bidirectional power flows i.e. they can either inject power to the grid or draw power from it. In recent years, the V2G technology has found a world wild attention due to its important advantages such as the peak load reduction and providing system reserve, to name a few. The unit commitment (UC) is a power system operation problem which is used to find the optimal operation schedule of generation units....
Concurrent orbit and attitude estimation using minimum sigma point unscented Kalman filter
, Article Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering ; Vol. 228, issue. 6 , 2014 , p. 801-819 ; Pourtakdoust, S. H ; Sharif University of Technology
Abstract
Concurrent orbit and attitude determination (COAD) plays a key role in reducing the cost of navigation and control subsystem for small satellites. This article is devoted to the problem of the COAD of satellites. A measurement package consisting of three axis magnetometer (TAM) and a sun sensor is shown to be sufficient to estimate the attitude and orbit information. To this end, an autonomous gyro-less COAD algorithm is proposed and implemented through the centralized data fusion of the TAM and the sun sensor. The set of nonlinear-coupled roto-translation dynamics of the satellite is used with a modified unscented Kalman filter (MUKF) to estimate the full satellite states. The MUKF is...
Spacecraft attitude and system identification via marginal modified unscented Kalman filter utilizing the sun and calibrated three-axis-magnetometer sensors
, Article Scientia Iranica ; Vol. 21, issue. 4 , 2014 , p. 1451-1460 ; Pourtakdoust, S. H ; Sharif University of Technology
Abstract
This paper deals with the problems of attitude determination, parameter identification and reference sensor calibration simultaneously. An LEO satellite's attitude, inertia tensor as well as calibration parameters of Three-Axis-Magnetometer (TAM) including scale factors, misalignments and biases along three body axes are estimated during a maneuver designed to satisfy the condition of persistency of excitation. The advanced nonlinear estimation algorithm of Unscented Kalman Filter (UKF) is a good choice for nonlinear estimation problem of attitude determination, but its computational cost is considerably larger than the widespread low accurate Extended Kalman Filter. Reduced Sigma Point...
Music emotion recognition using two level classification
, Article 2014 Iranian Conference on Intelligent Systems, ICIS 2014 ; Feb , 2014 ; 9781479933501 ; Sameti, H ; Sharif University of Technology
Abstract
Rapid growth of digital music data in the Internet during the recent years has led to increase of user demands for search based on different types of meta data. One kind of meta data that we focused in this paper is the emotion or mood of music. Music emotion recognition is a prevalent research topic today. We collected a database including 280 pieces of popular music with four basic emotions of Thayer's two Dimensional model. We used a two level classifier the process of which could be briefly summarized in three steps: 1) Extracting most suitable features from pieces of music in the database to describe each music song; 2) Applying feature selection approaches to decrease correlations...
A low power 1.2 GS/s 4-bit flash ADC in 0.18 μm CMOS
, Article Proceedings of IEEE East-West Design and Test Symposium, EWDTS 2013 ; 2013 ; 9781479920969 (ISBN) ; Sharifkhani, M ; Sadughi, S ; Sharif University of Technology
2013
Abstract
A low power 4-bit flash ADC is proposed. A new power reduction technique is employed which deactivates the unused blocks in the converter structure in order to reduce the power consumption. A new method for built-in threshold voltage generation together with a new offset calibration method is used to further reduce the power consumption in the converter. Monte-Carlo simulation shows that after calibration both the INL and the DNL are lower than 0.35 LSB. The converter achieves 3.5 effective number of bits (ENOB) at 1.2 GS/s sampling rate after the offset calibration is performed. It consumes 10 mW from a 1.8 V supply, yielding a FoM of 560 fJ/conversion.step in a 0.18 μm standard CMOS...
A rewarding-punishing coordination mechanism based on Trust in a divergent supply chain
, Article European Journal of Operational Research ; Volume 230, Issue 3 , 2013 , Pages 527-538 ; 03772217 (ISSN) ; Baboli, A ; Cheikhrouhou, N ; Modarres, M ; Akbari Jokar, M. R ; Sharif University of Technology
2013
Abstract
Coordination of decentralized supply chains using contract design is a problem that has been widely addressed in the literature. We consider a divergent supply chain including a supplier and several retailers producing fashion products with short sale seasons. The retailers cooperate with the supplier as sales agents; i.e.; they work in the framework of revenue sharing contracts. Because of their proximity to the market, retailers can provide more accurate demand forecasts to the supplier that is used to decide on issues such as capacity building and market prices with regard to retailers stiff due dates, different lead times and different price-dependent demand functions. To ensure abundant...
New SNDR enhancement techniques in pipelined ADC
, Article 2013 21st Iranian Conference on Electrical Engineering ; May , 2013 , Page(s): 1 - 5 ; 9781467356343 (ISBN) ; Safavi, S. M ; Sharifkhani, M ; Sharif University of Technology
2013
Abstract
Signal to Noise and Distortion Ratio (SNDR) is widely chosen for dynamic characterization of ADC. For pipelined ADC in which the inner circuits' errors accumulate at the output, analysis of the origins of SNDR and its characterization can be very hard. However, due to a relationship between maximum INL of ADC and the distortion in its output codes, SNDR can be derived as a function of maximum INL value and its position in output codes. Utilizing this relationship, this paper develops two methods for SNDR enhancement that do not cost much power. The 50k sampled Monte-Carlo simulation in the behavioral level indicates 75% increase in the possibility of having SNDR > 60db just by utilizing...
How to synchronize and register an optical-inertial tracking system
, Article Applied Mechanics and Materials ; Volume 332 , 2013 , Pages 130-136 ; 16609336 (ISSN) ; 9783037857335 (ISBN) ; Akbar, M ; Farahmand, F ; Sharif University of Technology
2013
Abstract
Multi-sensor tracking is widely used for augmentation of tracking accuracy using data fusion. A basic requirement for such applications is the real time temporal synchronization and spatial registration of two sensory data. In this study a new method for time and space coordination of two tracking sensor measurements has been presented. For spatial registration we used a body coordinate system and then applied the effect of the level arm. The time synchronization was done based on least mean square (LMS) error method. This method was implemented to synchronize the position and orientation of an object using Inertial (1IMU) and Optical (Optotrak) tracking systems. The results of synchronized...
Multi-objective genetic algorithm for hover stabilization of an insect-like flapping wing
, Article Applied Mechanics and Materials ; Volume 332 , 2013 , Pages 50-55 ; 16609336 (ISSN) ; 9783037857335 (ISBN) ; Banazadeh, A ; Sharif University of Technology
2013
Abstract
This paper describes latest results obtained on modeling, simulation and controller design of an insect-like Flapping Wing Micro Air Vehicle (FWMAV). Because of the highly nonlinear and time varying nature of insect flight and the inability to find an equilibrium point, linearization of the model without compromising the accuracy is not possible. Therefore, to address the problem of designing a controller capable of stabilizing and controlling the FWMAV around a hovering point, a metaheuristic optimization approach is proposed, based on the time averaging theorem. The results show that a controller, designed using the proposed method, is capable of stabilizing the FWMAV effectively around...
Design methodology and preliminary sizing of an unmanned mars exploration plane (UMEP)
, Article APPLIED MECHANICS AND MATERIALS; 332; 15; Biomechanics, neurorehabilitation, mechanical engineering, manufacturing systems, robotics and aerospace: optimization of the engineering systems; OPTIROB 2013 ; Volume 332 , 2013 , Pages 15-20 ; 16609336 (ISSN) ; 9783037857335 (ISBN) ; Banazadeh, A ; Golkhandan, A. R ; Sharif University of Technology
2013
Abstract
This paper discusses the mission requirements and design constraints for an Unmanned Martian research aircraft based on a tailor-made classical airplane design methodology. First, the exploration mission is described using the information from previous real-world experiences and the desired payload is proposed accordingly. The environmental conditions that dictate severe constraints to the design space are characterized afterwards. The conventional airplane design cycle is modified to address the lack of statistical data and to define a proper design recycling criteria. Eventually, the outcome is presented in the form of a novel configuration that is well suited to carry out the specified...
Frequency response analysis for dynamic model identification and control of a ducted fan aerial vehicle in hover
, Article Applied Mechanics and Materials, Neptun-Olimp ; Volume 332 , 2013 , Pages 56-61 ; 16609336 (ISSN) ; 9783037857335 (ISBN) ; Banazadeh, A ; Sharif University of Technology
2013
Abstract
System Identification is a key technology for the development and integration of modern engineering systems including unconventional flying vehicles. These systems are highly parametric with complex dynamics and nonlinearities. Ducted fans are special class of these vehicles that can take off vertically, hover and cruise at very low speed. In this paper, an exact equivalent linear system is found from the non-linear dynamic model of a ducted fan by use of frequency response identification. Here, power spectral density analysis is performed, using CIFER software, to evaluate the input-output responses in hover and to derive the transfer functions based on the coherence criterion. Then,...
Finite-SNR diversity-multiplexing tradeoff in multi-relay channels
, Article 2013 Iran Workshop on Communication and Information Theory ; 2013 ; 9781467350235 (ISBN) ; Gholami, E ; Rastegar, S. H ; Behroozi, H ; Sharif University of Technology
2013
Abstract
In this paper, we investigate the diversity-multiplexing tradeoff (DMT) for multi-relay channels in finite-SNR regime. In our analysis, we consider the decode and forward (DF) relaying strategy and a line of sight path from source to destination. First, we determine the outage probability in a multi-relay scenario and obtain its exact analytical expressions. Then, the outage probability of a multi-relay channel with relay selection is calculated and provided as a closed-form expression. Based on these results, we determine the DMT in finite-SNR regime. Finally, using simulation results, we show that our analysis has accurate results which coincides with that of obtained from Monte-Carlo...
Rate adaptation and power allocation for time-correlated MISO Rayleigh fading channel with delay-limited HARQ
, Article IEEE International Conference on Communications, 10 June 2012 through 15 June 2012 ; 2012 , Pages 3915-3919 ; 15503607 (ISSN) ; 9781457720512 (E-ISBN) ; Vakilinia, S ; Khalaj, B. H ; Sharif University of Technology
Abstract
In this paper, we consider the problem of optimum rate adaptation and power allocation to maximize the delay-limited throughput (DLT) in a time-correlated 2×1 MISO Rayleigh fading channel with Hybrid ARQ in Chase-Combining mode (HARQ-CC). To this aim, we have first formulated the DLT equation based on the outage probability for 2×1 MISO-HARQ channel. We show that exact analytical calculation of the outage probability is not tractable. Therefore, we approximate the outage probability using a log-normal approximation approach. Based on such approximation, optimal rate and power allocations are derived. Finally, using Monte-Carlo simulation, we show that the approximation method provides...