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    Simultaneous three-dimensional tracking of individual signals from multi-trap optical tweezers using fast and accurate photodiode detection

    , Article Optics Express ; Vol. 22, issue. 19 , Sep , 2014 , p. 23661-23672 Ott, D ; Nader, S ; Reihani, S ; Oddershede, L. B ; Sharif University of Technology
    Multiple-beam optical traps facilitate advanced trapping geometries and exciting discoveries. However, the increased manipulation capabilities come at the price of more challenging position and force detection. Due to unrivaled bandwidth and resolution, photodiode based detection is preferred over camera based detection in most single/dual-beam optical traps assays. However, it has not been trivial to implement photodiode based detection for multiple-beam optical traps. Here, we present a simple and efficient method based on spatial filtering for parallel photodiode detection of multiple traps. The technique enables fast and accurate 3D force and distance detection of multiple objects... 

    An experimental study on the kinematics of a skilled service in playing tennis

    , Article ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE), 12 November 2010 through 18 November 2010 ; Volume 2 , 2010 , Pages 565-568 ; 9780791844267 (ISBN) Ahmadi, S. M ; Shirzad, E ; Sajadi, B ; Cheraghi, M ; Haghighi, K ; Sharif University of Technology
    This paper studies the effective parameters of a skilled service in playing tennis and determines their relationship with skill deals. Effective service in tennis plays an important role in gaining more desirable result and the most important factor of success in getting scores depends on the player's skills in serving an effective service. The characteristics of a good service are the high speed of the ball and the precision of landing the ball. The several parameters affecting on these two characteristic in the service, are studied in this paper. Therefore, the Kinematic parameters of 8 Iranian professional tennis athletes of first division tennis league and also 8 non-professional Iranian... 

    Numerical study on the performance of Tesla type microvalve in a valveless micropump in the range of low frequencies

    , Article Journal of Micro-Bio Robotics ; Volume 8, Issue 3 , 2013 , pp 145-159 ; 21946418 (ISSN) Mohammadzadeh, K ; Kolahdouz, E. M ; Shirani, E ; Shafii, M. B ; Sharif University of Technology
    In this study, the performance of Tesla-type microvalves, used in micropumps for low frequency driving force, is examined. Three-dimensional and unsteady numerical analysis of fluid flow inside a valveless reciprocating micropump in the range of low working frequencies is carried out. Reciprocating movement of flow actuator provides the actuation and pumping of the working fluid. Ferrofluidic valveless micropump is one practical sample of this kind of micropumps that operate in the range of low working frequencies. To model the reciprocating movement of flow actuator, two time varying functions that includes sinusoidal and step excitation are employed. Also, the performance of... 

    Axial-flow compressor performance prediction in design and off-design conditions through 1-D and 3-D modeling and experimental study

    , Article Journal of Applied Fluid Mechanics ; Volume 9, Issue 5 , 2016 , Pages 2149-2160 ; 17353572 (ISSN) Peyvan, A ; Hajilouy benisi, A ; Sharif University of Technology
    Isfahan University of Technology 
    In this study, the main objective is to develop a one dimensional model to predict design and off design performance of an operational axial flow compressor by considering the whole gas turbine assembly. The design and off-design performance of a single stage axial compressor are predicted through 1D and 3D modeling. In one dimensional model the mass, momentum and energy conservation equations and ideal gas equation of state are solved in mean line at three axial stations including rotor inlet, rotor outlet and stator outlet. The total to total efficiency and pressure ratio are forecasted using the compressor geometry, inlet stagnation temperature and stagnation pressure, the mass flow rate... 

    A robust dual source level set method for three-dimensional echocardiography image segmentation

    , Article Journal of Theoretical and Applied Information Technology ; Volume 95, Issue 21 , 2017 , Pages 5701-5710 ; 19928645 (ISSN) Sahba, N ; Fatemizadeh, E ; Behnam, H ; Sharif University of Technology
    Echocardiography as a common place device has been widely used for diagnosis. Segmentation of left ventricle just using the standard level set formulation based on the magnitude of intensity cannot restrict the contour evolution completely due to the lack of sharp edges. This paper aims to introduce a robust method for segmentation of three-dimensional echocardiography images based on two boundary maps namely distance map and probabilistic map as stopping criteria of contour evolution which are extracted using two different approaches. The distance map is extracted by applying Free Form Deformation (FFD) method on manually determined landmarks of initial spherical volume to register the... 

    Multidimensional query based routing for virtual environments

    , Article 2009 IEEE International Conference on Virtual Environments, Human-Computer Interfaces, and Measurements Systems, VECIMS 2009, Hong Kong, 11 May 2009 through 13 May 2009 ; 2009 , Pages 107-112 ; 9781424438099 (ISBN) Zonjic, S ; Hariri, B ; Shirmohammadi, S ; IEEE Instrumentation and Measurements Society ; Sharif University of Technology
    In this paper we propose a new architecture based on Z-order curve and kd-tree that can efficiently handle issues related to update messages distribution to interested entities' locations in a three-dimensional (3D) virtual environments where locations are described in terms of 3D coordinates. We also aim to minimize the number of routing hops in distribution of update messages, especially when updates are forwarded to a specific range of users/entities in the virtual environment. Our results are promising and show improvements in both of the objectives. ©2009 IEEE  

    Experimental and numerical study of the effect of pulsating flow on the turbocharger turbine performance parameters

    , Article SAE Technical Papers ; Volume 2 , April , 2013 Tabatabaei, H ; Boroomand, M ; Taeibi Rahni, M ; Sharif University of Technology
    The pulsating flow in the exhaust gas of a SI engine causes an unsteady flow at the inlet to the turbocharger turbine. In a four cylinder four stroke engine, the pulse frequency varies between 20 and 200 Hz. Three dimensional pulsating flows in a vane-less turbocharger turbine of a 1.7 liters SI engine are simulated numerically and validated experimentally. Simulations are done for 720 degree engine cycle at three engine speeds. The results are shown the inlet pulsating flow has significant effects on several turbine parameters especially the inlet total pressure, the reduced mass flow rate and the efficiency. The results show a very good agreement between the three-dimensional unsteady... 

    The effect of normal stress on hydro-mechanical deep drawing process

    , Article International Journal of Mechanical Sciences ; Volume 53, Issue 6 , 2011 , Pages 407-416 ; 00207403 (ISSN) Assempour, A ; Taghipour, E ; Sharif University of Technology
    Normal stress has some role in the deformation analysis of hydroforming processes. In this study, analytical modeling is pursued to evaluate the effect of normal stress on the hydro-mechanical deep drawing (HDD) process. Analyses are carried out for axisymmetric elements of the formed cup-shaped part for increments of the punch travel. The formulations are obtained using mechanical and geometrical relations and the finite difference method, thereby being solved by proper numerical algorithms. Furthermore, in the present work, part thickness is variable, the loading and straining are non-proportional, and bending/unbending effects over the part curvature are considered. The results show that... 

    Three-dimensional reconstruction of heavily occluded pedestrians using integral imaging

    , Article 10th International Conference on Distributed Smart Cameras, ICDSC 2016, 12 September 2016 through 15 September 2016 ; Volume 12-15-September-2016 , 2016 , Pages 1-7 ; 9781450347860 (ISBN) Ghaneizad, M ; Aghajan, H ; Kavehvash, Z ; CEA; Univ. Bourgogne Franche-Comte; University Blaise Pascal ; Sharif University of Technology
    Association for Computing Machinery 
    In this paper, we propose a novel approach for handling the occlusion problem in pedestrian detection through optical principles. Our proposed framework is based on a popular three-dimensional imaging technique in optics, named integral imaging, in which multiple viewpoint images captured from a three-dimensional scene are used to extract range information of the scene. The proposed approach effectively reconstructs an unobstructed view of heavily occluded pedestrians simultaneously containing range information. The range information provided by our method can be used for foreground extraction and the reconstruction output can be used in various applications, such as people detection and... 

    Molecular interaction between three-dimensional graphene aerogel and enzyme solution: effect on enzyme structure and function

    , Article Journal of Molecular Liquids ; Volume 265 , 2018 , Pages 565-571 ; 01677322 (ISSN) Ehtesabi, H ; Bagheri, Z ; Eskandari, F ; Ahadian, M. M ; Sharif University of Technology
    New membrane materials and processes have been extensively developed due to urgent needs for much more economic separation processes. Recently, graphene has been confirmed to be an excellent separation membrane. As there is no support in the obtained three-dimensional (3D) architecture constructed from tubular graphene network, it is possible to take full advantage of the large surface of graphene. In this study 3D graphene aerogels were synthesized by a simple method and modified to adjust hydrophilicity of the samples to achieve high liquid volumetric rate. Modified samples were used for the filtration of the enzymes including amylase, cellulase, lipase and protease. Slightly differently... 

    Behavior of mass concrete using smeared crack approach in three dimensional problems

    , Article 11th International Conference on Fracture 2005, ICF11, Turin, 20 March 2005 through 25 March 2005 ; Volume 3 , 2005 , Pages 1999-2004 ; 9781617820632 (ISBN) Mirzabozorg, H ; Ghaemian, M ; International Congress on Fracture (ICF); European Structural IntegritySociety (ESIS); American Society for Testing and Materials (ASTM) ; Sharif University of Technology
    A smeared crack approach has been proposed to model the static and dynamic behavior of mass concrete in three-dimensional space. The proposed model simulates the tensile fracture on the mass concrete and contains pre-softening behavior, softening initiation, fracture energy conservation and strain rate effects under dynamic loads. It was found that the proposed model gives excellent results and crack profiles comparing with the available data under static loads. Morrow Point dam was analyzed including dam-reservoir interaction effects to consider its nonlinear seismic behavior. It was found that the resulted crack profiles are in good agreement with the contour of maximum principal stresses... 

    Perfect quantum state transfer in two- and three-dimensional structures

    , Article Physical Review A - Atomic, Molecular, and Optical Physics ; Volume 85, Issue 1 , 2012 ; 10502947 (ISSN) Karimipour, V ; Rad, M. S ; Asoudeh, M ; Sharif University of Technology
    We introduce a scheme for perfect state transfer in regular two- and three-dimensional structures. The interactions on the lattices are of the XX spin type with uniform couplings. In two dimensions, the structure is a hexagonal lattice, and in three dimensions, it consists of hexagonal planes joined to each other at arbitrary points. We will show that compared to other schemes, much less control is needed for routing, the algebra of global control is quite simple, and the same kind of control can upload and download qubit states to or from built-in read-write heads  

    A surface registration technique for estimation of 3-D kinematics of joints

    , Article Studies in Health Technology and Informatics, 19 January 2009 through 22 January 2009 ; Volume 142 , 2009 , Pages 204-206 ; 09269630 (ISSN) ; 9781586039646 (ISBN) Mostafavi, K ; Jafari, A ; Farahmand, F ; Sharif University of Technology
    This study proposes a new technique for registration of complicated freeform surfaces. The relationship between the initial and transferred location/orientation of a points cloud is formulated and then generalized within the framework of the influence surface modeling approach using least squares method. Results of case studies for estimation of the transformation matrix of articular surface of the knee joint in two scenes of MR images indicated high accuracies of ±1 mm and ±1 degree  

    Human detection in occluded scenes through optically inspired multi-camera image fusion

    , Article Journal of the Optical Society of America A: Optics and Image Science, and Vision ; Volume 34, Issue 6 , 2017 , Pages 856-869 ; 10847529 (ISSN) Ghaneizad, M ; Kavehvash, Z ; Aghajan, H ; Sharif University of Technology
    In this paper, a novel approach for foreground extraction has been proposed based on a popular three-dimensional imaging technique in optics, called integral imaging. In this approach, multiple viewpoint images captured from a three-dimensional scene are used to extract range information of the scene and effectively extract an object or a person, even in the presence of heavy occlusion. The algorithm consists of two parts: depth estimation and reconstruction of the targeted object at the estimated depth distance. Further processing of the resulting reconstructed image can lead to the detection of a face or a pedestrian in the scene, which may not otherwise be detectable due to partial... 

    Designing, modeling and wrench feasible workspace analysis of a 3D cable suspended robot for heavy loads handling applications

    , Article 39th International Symposium on Robotics, ISR 2008, Seoul, 15 October 2008 through 17 October 2008 ; 2008 , Pages 934-939 Hamedi, J ; Zohoor, H ; Sharif University of Technology
    The objective of this paper is designing, modeling and wrench feasible workspace analysis of a 3D cable suspended robot as IRPM (Incompletely Restrained Positioning Mechanism). This type of robots supports a load platform in space by less than or equal to six spatially arranged cables. We use the model of 6 cables spanned in the same manner as a Stewart parallel mechanism. This mechanism is suitable for the accurate positioning of heavy loads. Concentrating on the operations of heavy loads handling, studying the workspace and ways of increasing it is of high importance. Several workspaces exist amongst which the constant and total orientation statically reachable combined and wrench feasible... 

    Extended finite element method for three-dimensional large plasticity deformations on arbitrary interfaces

    , Article Computer Methods in Applied Mechanics and Engineering ; Volume 197, Issue 9-12 , 2008 , Pages 1100-1114 ; 00457825 (ISSN) Khoei, A. R ; Biabanaki, S. O. R ; Anahid, M ; Sharif University of Technology
    In this paper, the extended finite element method is presented for large elasto-plastic deformation in 3D solid mechanics problems. The X-FEM computational algorithm is presented in the framework of Lagrangian description in order to model the arbitrary interfaces in large deformations. In X-FEM, the material interface is represented independently of element boundaries and the process is accomplished by partitioning the domain with several tetrahedral sub-elements whose Gauss points are used for integration of the domain of elements. The interface between two bodies is modeled by using the X-FEM technique and applying a modified level set enrichment function. In order to simulate the... 

    Modeling of Oxygen Transport and Exchange in an Acinus

    , M.Sc. Thesis Sharif University of Technology Mortazavi Ashkzari, Mohammad Sadegh (Author) ; Saeedi, Mohammad Saeed (Supervisor)
    An acinus is defined as the complex of airways supplied by one first order respiratory or transitional bronchiole. In this part, the replenishment of oxygen at the alveolar surface occurs by a combination of convective air flow with diffusion of oxygen in the air. So for studying gas exchange in the lung, modeling gas species transport and exchange in an acinus is important. Due to lacking direct measurements of the distribution of oxygen (or carbon dioxide) concentration in the acinus, several mathematical models have been developed and studied by numerical simulations. But in none of them the influence of breathing pattern and the role of blood flow in restricting the gas exchange rate have... 

    3D Multi Target Tracking

    , M.Sc. Thesis Sharif University of Technology Najafzadeh, Nima (Author) ; Kasaei, Shohreh (Supervisor)
    The purpose of multi target tracking, is tracking multiple target in each frame of video sequences simultaneously. Object tracking encounters many challenges. Two major challenges of tracking problem that we focus on in them in this thesis are detecting object in each frame of video sequence and handling occlusion problem. Our proposed method for multi target tracking considers one target as a main target and other targets as subsidiary targets. Proposed method track objects in initial view by Kalman filter that is adapted and tuned for multi target tracking. In case of occlusion our method uses data from auxiliary view for handling occlusion. In auxiliary view objects that are occluded in... 

    Three-dimensional resolvability in an integral imaging system

    , Article Journal of the Optical Society of America A: Optics and Image Science, and Vision ; Volume 29, Issue 4 , 2012 , Pages 525-530 ; 10847529 (ISSN) Kavehvash, Z ; Martinez Corral, M ; Mehrany, K ; Bagheri, S ; Saavedra, G ; Navarro, H ; Sharif University of Technology
    The concept of three-dimensional (3D) resolvability of an integral imaging system is thoroughly investigated in this research. The general concept of 3D resolution fails to describe the 3D discrimination completely. Then the concepts of the depth-resolution plane and lateral-resolution plane are introduced to show the difference between the conventional 3D spatial resolution and the newly introduced 3D resolvability. Therefore, the different properties of these planes for differentiating lateral spatial variations and axial variations are analyzed in this paper. The theoretical statements are demonstrated experimentally  

    Endurance time method for multi-component analysis of steel elastic moment frames

    , Article Scientia Iranica ; Volume 18, Issue 2 A , 2011 , Pages 139-149 ; 10263098 (ISSN) Valamanesh, V ; Estekanchi, H. E ; Sharif University of Technology
    The Endurance Time (ET) method is a time history-based dynamic analysis procedure which uses special intensifying acceleration functions for evaluation of the seismic response of structures. One of the potential applications of the ET method is in the three-dimensional analysis of buildings under multidirectional excitations. In this paper, considering horizontal components of excitation, an algorithm for the multi-component analysis of building structures by the ET method is proposed, and results of the ET method for various steel moment frames with 1 to 7 stories are compared with results from time history analysis with real earthquakes. Results show that based on recommendations of...