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The Impact of Watermarking on Digital Video Bitrate
, M.Sc. Thesis Sharif University of Technology ; Ghanbari, Mohammad (Supervisor)
Abstract
Nowadays with development of applications that stream video over internet, compression efficiency of video has become very important. On the other hand, Watermarking and video coding are two conflicting technologies. One adds redundancy and other tries to remove it. We have proposed a H.264 watermarking method that does not increases the bit rate. Unlike most of watermarking schemes, this methods embeds the watermark in inter coded frames. Abundance of these frames in video is impressively more than intra frames, so a lot of capacityis eventuated. But these frames are highly compressed using motion compensation, and are very sparse. To avoid from bit rate increment, this method only embeds...
Feedback control of the neuro-musculoskeletal system in a forward dynamics simulation of stair locomotion [electronic resource]
, Article Proc. of IMechE Part H: Journal of Engineering in Medicine ; 2009, Vol. 223, No. 6, pp. 663-675 Journal of NeuroEngineering and Rehabilitation ; Volume 11, Issue 1, 30 April 2014, Article number 78 ; Meghdari, Ali ; Vossough, Gholam Reza ; Sharif University of Technology
Abstract
The aim of this study is to employ feedback control loops to provide a stable forward dynamics simulation of human movement under repeated position constraint conditions in the environment, particularly during stair climbing. A ten-degrees-of-freedom skeletal model containing 18 Hill-type musculotendon actuators per leg was employed to simulate the model in the sagittal plane. The postural tracking and obstacle avoidance were provided by the proportional—integral—derivative controller according to the modulation of the time rate change of the joint kinematics. The stability of the model was maintained by controlling the velocity of the body's centre of mass according to the desired centre of...
Aeroelastic Modeling of a Flexible Hybrid FMAV for 3D Controlled Flight
, M.Sc. Thesis Sharif University of Technology ; Pourtakdoust, Hossein (Supervisor)
Abstract
Propulsive efficiency of flapping wings is optimized via a combination of flapping and elastic wing behavior. In this thesis, a complex complete model of flapping air vehicles (FAV) is developed in order to simulate the wing aeroelastic behavior. The resulting model is in the form of a complex set of partial differential equations whose solution is only numerically possible. Using the resulting simulation model, the different flapping behavior of the right and left wings can also be evaluated along with the resulting forces and moments that make the FAV flight realizable. One of the key flight conditions considered in many simulations is that of cruise flight. In order to have a...
Multi-Location Project Management Using Cloud Computing
, M.Sc. Thesis Sharif University of Technology ; Houshmand, Mahmoud (Supervisor)
Abstract
This research discusses the issue of exploitation of cloud computing in facilitating the responsibilities of a project manager in construction project management. The need for reliable and affordable technologies is ever more important in today's business world due to the amount of economic contraction and losses that take place every day; cloud computing fills this gap. For this purpose, we are presenting a cloud-based Project Management Software named Field wire that is specially designed to manage construction projects in the cloud computing environment. The various procedures of a project, due to their complex nature, are largely made up of tasks which cannot be carried out by one...
Developing an Applied Model for Energy Management in Dairy Production Industry
, M.Sc. Thesis Sharif University of Technology ; Mokhtar, Ali Reza (Supervisor) ; Miremadi, Ali Reza (Supervisor)
Abstract
Reviewing trends of energy consumption in the world reveals that sooner or later energy resources will be depleted. This concerning rate of consumption has brought about more greenhouse gases (GHG) emission influencing deleteriously on environment and climate. Human has continued energy consumption to maintain and improve the quality of his life through industrial production. Industry as a significant energy user owns considerable contribution to this consumption. Several attempts have been carried out to develop energy management systems in order to improve the energy efficiency of industrial sectors. Whilst they are comprehensive and could be applied to any sector, there is lack of...
Sliding mode control with online fuzzy tuning: Application to a robot manipulator
, Article IEEE International Conference on Mechatronics and Automation, ICMA 2005, Niagara Falls, ON, 29 July 2005 through 1 August 2005 ; 2005 , Pages 1357-1362 ; 0780390458 (ISBN); 9780780390454 (ISBN) ; Vossoughi, G. R ; Sharif University of Technology
2005
Abstract
This paper presents an approach to improve the sliding mode controller performance. Accordingly, a fuzzy controller is designed based on a limited number of rules and independent of the sliding mode controller complexity. To enhance the performance, this controller will continuously optimize the sliding mode controller parameters including hitting control gain, boundary layer thickness, sliding surface slope and intercept. The controller is applied to a two-degree-of-freedom robot and the experimental results are compared with a QFT based and a PID controller. The results demonstrate the significant performance improvement of the proposed controller. © 2005 IEEE
An Experimental Study of the Effects of Sweep Wing on the Boundary Layer of 2D Wing
, M.Sc. Thesis Sharif University of Technology ; Soltani, Mohammad Reza (Supervisor) ; Davari, Ali Reza (Co-Advisor)
Abstract
The behavior of boundary layer under the effect of the sweep angle is considered. The measurements were performed by a pitot tube rake. Three models with various sweep angels at angles of attack -2, 0 and 2 degree were tested. Both tip and root of all wings were closed by flat plates in order to prevent the flow to roll-up. However the flow field on the wing was still three-dimensional because of the sweep angle. The velocity on the wing has two components; longitudinal and lateral. The cross flow emerges due to the non-equilibrium of pressure and centrifugal forces. The velocity profiles showed that the magnitude of cross flow was stronger near the leading edge of the wing. The cross flow...
Optimal Batch Production for a Single Machine System with Rework
, M.Sc. Thesis Sharif University of Technology ; Haji, Ali Reza (Supervisor)
Abstract
This research attempts to develop the optimal solution for an inventory problem consisting of a single machine which produces items some of which may be defective. We assume that no shortages are allowed and all defective items are to be reworked. Setup cost for rework and waiting time of defectives are considered. This research consists of two different parts. In the first part we consider two different policies where in the first policy in each cycle after the regular production the machine is setup for the rework of defectives of the same cycle. In the second policy several cycles constitute a period. All the defectives produced in the period are reworked in the last cycle of that period....
Improving the Reliability of Energy Harvesting Wireless Sensor Networks
, M.Sc. Thesis Sharif University of Technology ; Ejlali , Ali Reza (Supervisor)
Abstract
Energy harvesters are used in today’s Wireless Sensor Networks (WSNs) to harvest the energy from the environment. One of the important advantages of the energy harvesting sensor networks over battery-operated sensor networks is that the use of the energy harvester prolongs the life time of the nodes, while a battery-operated node becomes useless once its energy runs out. Although an energy harvester can provide a supply source with a lifetime much greater than a battery, the amount of available energy for an energy harvesting system is a random variable and is not as predictable as the energy of a battery. This unpredictability may cause reliability problems. In order to solve the existing...
Energy Management in Energy Harvesting Wireless Sensor Nodes
, M.Sc. Thesis Sharif University of Technology ; Ejlali, Ali Reza (Supervisor)
Abstract
Wireless Sensor Networks have become widespread because of their flexibility, applicability and ability to precept data with high accuracy. However, the most limiting factor in their usage is the amount of available energy in nodes since energy depletion in a node means that it is dead, therefore many efforts have been done for optimum energy management in Wireless Sensor Networks. In many cases, the key solution to prolong the network lifetime is load balancing. In this way, all the nodes will die (approximately) together and the lifetime of network will be maximized. Load balancing can be implemented in all layers from physical layer to application. It should be noted that it is not always...
Gaining Competitive Advantage through Marketing Strategies in Container Terminal: A Case Study on Shahid Rajaee Port in Iran
, M.Sc. Thesis Sharif University of Technology ; Miremadi, Ali Reza (Supervisor)
Abstract
The competitiveness of a port convinced shipping lines and shippers with a significant basis in selecting a port. Port authorities and port operators can make use of the competitive advantage as a parameter for counter measures by grasping the advantages and disadvantages of the ports and be a prime factor of opportunities and threats of the ports. Ports have a significant role in today’s networked business environment. They are being regarded as hubs that are part of various logistic systems. The very essence of a seaport is to link maritime networks and land network. These networks for the port are means of analyzing its competitiveness. A port overall competitiveness is determined by it’s...
Experimental Investigation of Mechanical Behavior of Structural Concrete with Combination of Waste Glass and Silica Fume
, M.Sc. Thesis Sharif University of Technology ; Khaloo, Ali Reza (Supervisor)
Abstract
Concrete is the second most structural material in the world. So attention and promotion of the concrete mix design with respect to variable issues and requirements, is very important. On the other hand, these days environment and its pollution has become very popular discussion. Waste-glass which is produced by human products is one of the environmental pollutants. In this thesis it replaces some aggregate in concrete and it can reduce the level of this material in the world. Also we study effects of silica-fume as cement replacement and properties enhancer in our concrete mix design and see how it can ...
Strengthening RC Slabs under Various Loads and Boundary Conditions Using FRP Composites
, M.Sc. Thesis Sharif University of Technology ; Khaloo, Ali Reza (Supervisor)
Abstract
In recent decades the use of FRP materials for strengthening structures has been developed extensively, thanks to their high strength, sufficient stiffness, high durablity, and ease of use. A great deal of research has been conducted on strengthening reinforced concrete beams and columns with FRP composites. By contrast, not many researches are performed on slabs, especially two-way slabs. In these few researches, the loading and boundary conditions are limited to simplest ones. Therefore, in this thesis, the focus of attention is on strengthening reinforced concrete slabs under various loads and boundary conditions using FRP composites.
In this thesis, first, FRP composites and their...
In this thesis, first, FRP composites and their...
Selecting a Sustainable and Resilient Supplier in Cold Supply Chain Using Grey Multiple Criteria Decision Making Techniques
, M.Sc. Thesis Sharif University of Technology ; Hajji, Ali Reza (Supervisor)
Abstract
Supplier selection is a strategic decision that has a key impact on the success of the supply chain. Due to the nature of goods and storage conditions in the cold supply chain has a great impact on environmental pollution compared to other chains, and it also has the possibility of disrupting the chain due to the importance of temperature and time conditions. Currently, due to the spread of international pressures on the observance of environmental and social principles, the issue of choosing a sustainable supplier has been raised. Also, the expansion of supply chains has caused the challenges and risks faced by supply chains to expand and disrupt the chain, so the decision of supply chain...
Response of Curved RC Shear Walls Under Cyclic Loading
, Ph.D. Dissertation Sharif University of Technology ; Khaloo, Ali Reza (Supervisor)
Abstract
Reinforced concrete (RC) shear walls with a curved cross-section are appealing structural elements to architects and engineers due to the aesthetic and structural advantages. Owing to the paucity of decent experimental research on curved RC shear walls (CRCSWs), the seismic response of these structural elements is essentially unknown. In that regard, this study includes research on a high-demanding type of structural element, which has found its application in North America, Europe, Asia, and to some extent in the Middle East with relatively no design specifications and laboratory research, structural analysis, and design methodology. Therefore, in order to provide an insight into the...
Sparse Representation with Application to Image Inpainting
, M.Sc. Thesis Sharif University of Technology ; Marvasti, Farrokh (Supervisor)
Abstract
The emerging field of compressed sensing has found wide-spread applications in signal processing. Exploiting the sparsity of natural image signals on basis of a set of atoms called dictionary, one can find numerous examples for applications of compressed sensing in the field of image processing. One of these interesting applications is to help recover missing samples of a damaged or lossy image signal which is also known as image inpainting. There are dozens of reasons why an image may get damaged, for instance, during data transmission, some blocks of an image (or frames of a video ) may get lost due to error in the telecommunication channel (this is known as block-loss). In this case image...
Sparse recovery of missing image samples using a convex similarity index
, Article Signal Processing ; Volume 152 , 2018 , Pages 90-103 ; 01651684 (ISSN) ; Zayyani, H ; Marvasti, F ; Sharif University of Technology
2018
Abstract
This paper investigates the problem of recovering missing samples using methods based on sparse representation adapted for visually enhanced quality of reconstruction of image signals. Although, the popular Mean Square Error (MSE) criterion is convex and simple, it may not be entirely consistent with Human Visual System (HVS). Thus, instead of ℓ2-norm or MSE, a new perceptual quality measure is used as the similarity criterion between the original and the reconstructed images. The proposed criterion called Convex SIMilarity (CSIM) index is a modified version of the Structural SIMilarity (SSIM) index, which despite its predecessor, is convex and uni-modal. We derive mathematical properties...
Fabrication and Characterization of ZnO Composites Nanofibers by Electrospinning Method for Photocatalytic Application
, Ph.D. Dissertation Sharif University of Technology ; Moshfegh, Ali Reza (Supervisor) ; Pourjavadi, Ali (Co-Advisor)
Abstract
In this research we focus on study and fabrication of ZnO composite nanofibers by electrospinning method for photocatalytic application. The most important challenges in the field of photocatalyst are photocatalytic activity under the visible light and efficiency enhancement. ZnO is a wide band gap semiconductor and it is not active under the visible light. In Iran, we have more than 300 sunny days in a year. Therefore fabrication and application of photocatalytic material with activity under the sun light that contained 40% of visible light is so vital in our country. In the first part of this project, ZnO-CNT nanofibers were fabricated and carbon doped in the crystal lattice of the ZnO....
The Exploratory Study of Customer Satisfaction & Loyalty in Private Access Provider (PAP)Companies: ADSL Internet Case in Iran
, M.Sc. Thesis Sharif University of Technology ; Miremadi, Ali Reza (Supervisor)
Abstract
Internet and the market based on this new product and service has penetrated in all aspects of today’s modern life of human being. After invention of this market each day a new innovation revolutionized this market and industry. High speed internet based on ADSL technology was one of these innovations. The high-speed internet service has achieved a remarkable increase in penetration in recent years. In order to survive in this competitive market, companies should continue to improve their service performance. The high level of service performance is believed to be an effective way to improve customer satisfaction and loyalty. In recent years, the high-speed internet service, based on the...
Low-power Design of Decimal Multipliers
, M.Sc. Thesis Sharif University of Technology ; Ejlali, Ali Reza (Supervisor)
Abstract
Decimal multiplication is a frequent operation with inherent complexity in implementation. Commercial and financial applications require their data to be precise while binary number system cannot ensure precision. Existing research works on parallel decimal multipliers have mainly focused on latency and area as two major factors to be improved. However, energy/power consumption is another prominent issue in today’s digital systems. Hence, in this thesis we present a comparative study of parallel decimal multipliers, considering energy/power consumption (leakage and dynamic power consumption), latency and area. Furthermore, we present two novel techniques to reduce energy/power consumption of...