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Optimal design of stiffened plates for buckling under in-plane forces and bending moments
, Article Proceedings of the Eight International Conference on Civil and Structural Engineering Computing, Vienna, 19 September 2001 through 21 September 2001 ; 2001 , Pages 83-84 ; 0948749768 (ISBN) ; Askarian, A ; Gashtasby, M ; Sharif University of Technology
2001
Abstract
The optimal design of stiffened plates for buckling under in-plane forces and bending moments was presented. The virtual work principle was applied in order to calculate the buckling coefficient and the critical load factor of the stiffened plates. It was observed that the buckling coefficient is a function of the displacement coefficients
ECG beat classification based on a cross-distance analysis
, Article 6th International Symposium on Signal Processing and Its Applications, ISSPA 2001, Kuala Lumpur, 13 August 2001 through 16 August 2001 ; Volume 1 , 2001 , Pages 234-237 ; 0780367030 (ISBN); 9780780367036 (ISBN) ; Nayebi, K ; Sharif University of Technology
IEEE Computer Society
2001
Abstract
This paper presents a multi-stage algorithm for QRS complex classification into normal and abnormal categories using an unsupervised sequential beat clustering and a cross-distance analysis algorithm. After the sequential beat clustering, a search algorithm based on relative similarity of created classes is used to detect the main normal class. Then other classes are labeled based on a distance measurement from the main normal class. Evaluated results on the MIT-BIH ECG database exhibits an error rate less than 1% for normal and abnormal discrimination and 0.2% for clustering of 15 types of arrhythmia existing on the MIT-BIH database. © 2001 IEEE
A new soft-handoff management algorithm with two decision boundaries
, Article 12th International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC 2001), San Diego, CA, 30 September 2001 through 3 October 2001 ; Volume 1 , 2001 , Pages D54-D58 ; Salehi, J. A ; Aref, M. R ; Nasiri Kenari, M ; Sharif University of Technology
2001
Abstract
One of the most prominent features of code division multiple-access (CDMA) cellular networks is their ability for applying soft-handoff. This type of handoff results in a better supporting of seamless communication services, capacity enhancement, QoS improvement, etc. Because of existence of more parameters and flexibilities compared to hard-handoff, an optimum solution for soft-handoff management and admission control for new and handoff calls is necessary. In this paper we propose a new algorithm with two thresholds for admission of new and handoff calls, and with two decision boundaries for controlling of handoff traffic. We compare this algorithm with a simpler one with only one decision...
Adaptive CFAR processor for nonhomogeneous environments
, Article IEEE Transactions on Aerospace and Electronic Systems ; Volume 36, Issue 3 PART 1 , 2000 , Pages 889-897 ; 00189251 (ISSN) ; Mohammad, K ; Bastani, H ; Sharif University of Technology
2000
Abstract
A new constant false alarm rate (CFAR) processor is presented, that exhibits a noticeable detection performance in the presence of interfering targets, as well as an excellent false alarm rate (FAR) regulation at the clutter power transition regions. The presented CFAR processor, which is designed to work on the logarithmic amplified video signals, can also easily adapt itself to new environmental conditions. Furthermore, in the steady state, its performance does not depend on the background noise power. Simulation results show the obvious preference of the presented processor to the conventional GOCA-LOG/CFAR, regarding FAR regulation at the clutter power transition regions. Noncoherent...
A low-voltage low-power switched-capacitor filter using a new transistor configuration
, Article 12th International Conference on Microelectronics, ICM 2000, 31 October 2000 through 2 November 2000 ; Volume 2000-October , 2000 , Pages 99-102 ; 9643600572 (ISBN) ; Atarodi, S. M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2000
Abstract
A novel cascode configuration previously presented as a high output resistance load (Fujimori and Sugimoto, 1998) has been investigated and utilized for amplification to achieve higher gain and bandwidth by the authors (Lofti and Atarodi, Proc. ICEE'00, vol.1, pp.83-8, 2000). A low-voltage single-stage opamp using this configuration is designed. Finally, based on this idea a 1.5-V offset- and gain-compensated 5th order switched-capacitor low pass filter with only 150 μA current consumption in a 0.8 μm process is designed. © 2000 IEEE
Effect of Iron Ore Concentrate Morphology on Pellet Quality of Gol-e-Gohar Concentrate
, Ph.D. Dissertation Sharif University of Technology ; Halali, Mohammad (Supervisor)
Abstract
In this study, the effect of iron ore concentrate morphology on green pellet quality was studied. In order to produce concentrate with different morphology using ball mill, ball charge (20-40 %V), grinding time (30-50 min) and ball distribution (15 mm, 23 mm, 15+23 mm) was varied. It was deduced that increasing grinding time and ball charge would result in reduction of D80 but would increase Blaine number. The interaction parameters of ball distribution-grinding time and ball distribution-ball charge had significant effect on Blaine and D80. It was also observed that mixed level of ball distribution would lead to higher Blaine numbers. The equation obtained by CCD was verified by the...
Analysis of Profit Pool in Energy Industry of Iran and Examining the Future of this Industry
, M.Sc. Thesis Sharif University of Technology ; Talebian, Masoud (Supervisor)
Abstract
Unequal distribution of profit and income in different sectors of industries creates a challenge for investors and their managers to determine the level of concentration and investment in each industry sector. The energy industry, as one of the most important ones in the country, will not be an exception to this rule. Iran, as a country with a competitive advantage in the world in this industry, can take the path of development if this industry is used correctly and to the maximum. Also, owners, regulators and investors of this industry must constantly monitor it so that they can determine its growth. This research aims to closely monitor this industry to create guidelines for all the people...
Improving the Design of Menus in User Interfaces
, M.Sc. Thesis Sharif University of Technology ; Heydarnoori, Abbas (Supervisor)
Abstract
The design and development process of menu systems has always been a focus of researchers and engineers in the fields of software engineering and human-computer interaction. Considering the large and complex nature of the design space, it is nec- essary to provide automatic methods that aid designers during the design process. In this study, natural language processing is used to investigate the semantic relationship between menu system commands. Users expect related commands to be conveniently located next to each other, and a properly designed interface satisfies this need. As a result of this research, a fast-text-based model is developed that uses the data of past menu systems. In a...
Design, Development, and Test of a Magnetic Nano Monowing
, M.Sc. Thesis Sharif University of Technology ; Banazadeh, Afshin (Supervisor)
Abstract
In the present study, an attempt has been made to design and develop a nano drone using the dynamics of single-wing drones. To reduce the noise associated with nano-drone motors, a unique magnetic system has been developed for the drone's propulsion system, which has technology similar to magnetic trains and uses the theory of magnetic suspension, which is one of the main innovations of this dissertation. The drone designed in this research will have a blade with a radius of 15 cm and its total weight will be 170 grams, which according to the thrust of the blade will be able to carry a load of 50 grams for 14 minutes. In this research, after the initial design of the drone and related...
Quantification of Partial Similitude and Multi-Fidelity Design Optimization of Dynamic Similar Models
, Ph.D. Dissertation Sharif University of Technology ; Banazadeh, Afshin (Supervisor)
Abstract
In this thesis, a framework for measuring the relative dynamic similarity and multi-fidelity design of the dynamic similar model of aircraft is presented. The conditions for establishing dynamic similarity between the scaled model and the original aircraft have been investigated for different applications and the methods for establishing relative dynamic similarity have been studied. In related researches conducted in the field of designing similar dynamic models of flying devices, the degree of relative similarity has not been measured and usually one or more scaling laws have been omitted according to the type of application. In this thesis, it has been shown that partial dynamic...
Optimization of Distribution and Stiffness of Connections in Steel Frames by Value based Seismic Design
, M.Sc. Thesis Sharif University of Technology ; Esmail Pourestekanchi, Homayoon (Supervisor)
Abstract
Structural optimization has always been one of the concerns of engineers. Usually, engineers decide to optimize the structure with its weight. Nowadays we know that the best solution in weight optimization is not good for the structural damage and performance of the structure due to risk analysis.In this study, using the genetic algorithm to reduce construction cost, Loss and damaged cost and total cost of the structure by calculating structural damage based on FEMA-P58 guidelines according to two types of connections (rigid or hinge) and their elements (beams and columns) in two types of structures 4 and 8 story has been investigated.At each stage of increment in algorithms, first, the...
Recuperator Design of a 100kW Aviation Gas Turbine and its Integrated Performance Analysis with the Aircraft
, M.Sc. Thesis Sharif University of Technology ; Ghorbanian, Kaveh (Supervisor)
Abstract
The increasing need for more efficient and environmentally friendly microturbines necessitates the utilization of compact recuperators resulting in lower fuel consumption and emissions. The goal of this research is to determine the performance behavior of a primary surface recuperator to be incorporated in a 100 kW microturbine. Primary surface recuperator, known for relatively favorable characteristics in heat transfer, low weight, and high efficiency is considered as a candidate in aviation engines. In this research, a computational model for heat transfer and pressure losses is used for the design optimization of annular involute-profile cross wavy primary surface recuperators in...
Waveform Design for Interference Mitigation in SAR Imaging and Sparse Image Recovery
, M.Sc. Thesis Sharif University of Technology ; Karbasi, Mohammad (Supervisor)
Abstract
In this research, we design a compatible waveform for the purpose of high-quality synthetic aperture radar (SAR) imaging in conjunction with sparse recovery methods for image formation. The goal is to make the imaging system tolerable against the wide-band and narrowband electromagnetic interferences. Actually, we consider minimizing the mutual interference between our radar and coexisting licensed emitters and minimizing the jamming signal (unlicensed emitters) power while enforcing some constraints over the waveform features like peak-to-average-power ratio (PAPR). For the constrained optimization problem to design a proper waveform, we introduce a new constraint to the optimization...
Reliability-Based Multidisciplinary Design Optimization Under Uncertainty for Reusable Flexible Launch Vehicle Using Genetic Algorithm
, M.Sc. Thesis Sharif University of Technology ; Fathi Jegarkandi, Mohsen (Supervisor)
Abstract
In this research, a Reusable Flexible Launch Vehicle (RFLV) design problem is presented by Multi-Disciplinary Design Optimization (MDO) approach in primary design phase. Trajectory, structure, aerodynamic, aeroelasticity and thermal protection system are considered as involved disciplines in design problem. The study purpose will be to obtain an optimal trajectory which meets all the control and structure limitation while the estimating body skin and thermal protection thicknesses base on structural evaluating in re-entry trajectory is in process. The flexible launch vehicle body is considered as a free-free Bernoulli-Euler beam and D’alembert’s principle addresses inertia force in static...
Value-based Optimal Design of FPB and LRB Isolators for Short to Medium Rise Buildings
, Ph.D. Dissertation Sharif University of Technology ; Esmail Pourestekanchi, Homayoon (Supervisor)
Abstract
Seismic base isolation is the most effective method of protecting and strengthening structures against seismic damage caused by large to small earthquakes and aftershocks. Providing damping and energy absorption of the seismic isolation at the structure's base level can significantly reduce the cost of repairing and strengthening the structure in addition to reducing seismic damage. However, besides these advantages, due to their high cost, seismic isolations in major infrastructure projects, hospitals, and crisis management centers should have economic and social justification. In this regard, a value-based seismic design approach can justify this important issue. In recent years of...
Fair Multi-Dose Multi-Vaccine Distribution with Uncertain Demand
, M.Sc. Thesis Sharif University of Technology ; Haji, Alireza (Supervisor) ; Fatahi Valilai, Omid (Supervisor)
Abstract
Among disasters, outbreaks of pandemics account for excessive human and material damages,including a significant number of deaths. During any pandemic and once an or a set of effective vaccines have been identified/produced, governments all around the world enter a crucial phase when a crucial demand for an effective global vaccination campaign arises to vaccinate the population to stop/avoid the disease, knowing that the vaccines are not immediately available and may even become available with considerable delays (i.e., delivery and validation delays). Therefore, such phase of a pandemic is very crucial to identify and produce effective vaccines as well as to globally and equitably...
Aerodynamics Design of Aviation High-speed Radial Turbine with a Feasibility on Cooling
, M.Sc. Thesis Sharif University of Technology ; Ghorbanian, Kaveh (Supervisor)
Abstract
Radial turbines with small dimensions and in small power capacities are of great interest. In general, turbine performance improvement and higher output power may be achieved through increasing the inlet mass flow rates however at the expense of more weight and larger dimensions. On the other hand, increasing the inlet total temperature to the turbine will result in higher power potentials. Nevertheless, the turbine needs to be cooled in case that the intended inlet temperature goes beyond the turbine material limitation. In this thesis, radial turbine equations are reviewed and the logic of a 1D algorithm is developed where parameters like the total temperature, total pressure, and mass...
Development of an Intelligent Mission Based Orbital Design Environment for Earth Satellites
, M.Sc. Thesis Sharif University of Technology ; Pourtakdoust, Hossien (Supervisor)
Abstract
Nowadays there are various means in the field of orbital mechanics used in different levels and their accuracy depends on the theory and complexity of the governing equations used in their development. Most of them just simulate the motion of an orbiting satellite while there exist some commercial products able to provide the user with the orbital performance specifications and almost none of them have a module to design an orbit, based on a required performance such as specific coverage / ground track, shadow/light duration, etc .... Although satisfying performance requirements and a set of orbital elements simultaneously only seems to be possible for some particular orbits, there is an...
An Adaptive and Energy Aware Data Allocation for Scratchpad Memory in Energy Harvesting Systems with Non-volatile Memory
, M.Sc. Thesis Sharif University of Technology ; Ejlali, Alireza (Supervisor)
Abstract
Energy consumption is considered as one of the key constraints in the design of Embedded Systems. Exploiting abundant ambient energy offers a practical solution for designing embedded systems. In this regard, emerging trends are surging towards replacing battery-powered embedded systems in various different applications such as wearable systems, Internet of Things, and pervasive computing. Also, with the development and ommercialization of emerging Non-volatile memory technologies,the potential to reduce the static energy consumption and the ability to retain data in the absence of input energy, has become practically feasible for Embedded Systems. Consequently, recent researches have...
Aerodynamic Design of Axial Compressor Blade of The Gas Turbine
, M.Sc. Thesis Sharif University of Technology ; Hajilouy Benisi, Ali (Supervisor)
Abstract
Improving compressor performance and arriving at better conditions has always been considered by researchers and industrialists. However axial compressor design process is time consuming, very costly, and involves uncertainties and iterations such that sometimes the preset targets are not achieved. Therefore it is required to be able to perform preliminary design and specify the compressor geometry and blade specifications and predict the performance characteristics with a fast, cheap method with required accuracy suitable for this step before detailed design and manufacture. Also some design methods need a primary geometry that is generated by these methods.In this work, towards achieving...