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    Correction to: parametric study and working fluid selection of modified combined power and refrigeration cycles (MCPRCs) using low-temperature heat sources (Journal of the Brazilian Society of Mechanical Sciences and Engineering, (2018), 40, 1, (30), 10.1007/s40430-018-0971-5)

    , Article Journal of the Brazilian Society of Mechanical Sciences and Engineering ; Volume 40, Issue 2 , February , 2018 ; 16785878 (ISSN) Rostamzadeh, H ; Ghaebi, H ; Sharif University of Technology
    Springer Verlag  2018
    Abstract
    The original version of this article unfortunately contained a mistake. The affiliation of the second author was incorrect. The correct information is given below: Hadi Ghaebi, Department of Mechanical Engineering, Faculty of Engineering, University of Mohaghegh Ardabili, P.O. Box 179, Ardabil, Iran. © 2018, The Brazilian Society of Mechanical Sciences and Engineering  

    An analytical and experimental study of precision forging of aluminum spur gear

    , Article Steel Research International, 16 September 2012 through 19 September 2012, Krakow ; Volume SPL. ISSUE , September , 2012 , Pages 163-166 ; 16113683 (ISSN) ; 9783514007970 (ISBN) Irani, M ; Taheri, A. K ; Sharif University of Technology
    Wiley-VCH Verlag  2012
    Abstract
    An important aspect of production of gears by precision forging process is the prediction of load required to perform the process and to design the forging die. In this research a new kinematically admissible velocity field is presented to predict the forging load by an upper bound analysis. The analysis considers the shape of tooth profile, number of teeth, and frictional conditions between the die/punch and deforming material. To verify the predicted results the 7075 aluminum alloy billets were forged at temperature of 150 to 250 °C in a precision forging die designed to produce a spur gear of 5 teeth. A good agreement was found between the two sets of results at the filling stage of the... 

    Timing Analysis of LYSO-based Crystals

    , M.Sc. Thesis Sharif University of Technology Hassanshahi, Mohammad Hassan (Author) ; Arfaei, Hessamaddin (Supervisor) ; Bornheim, Adolf (Supervisor)
    Abstract
    The Large Hadron Collidor (LHC) will increase its luminosity to more than 10e35 cm-2 s-1. The large amount of data rates will provide enough datasets needed to probe rare Higgs processes, study the scattering of longitudinally polarized W bosons and physics beyond the standard model(BSM). In the upgraded version of the LHC, called High Luminosity LHC (HL-LHC), the number of simultaneous interactions per bunch crossing, aka pile-up, increases to 140-200. The large number of pile increases the possibility of confusion in distinguishing vertexes of interest due to the contamination from non-interesting vertexes. One of the methods to mitigate the pile-up, complementary to the precision tracking... 

    Designing a LQR controller for an electro-hydraulic-actuated-clutch model

    , Article Proceedings of 2016 2nd International Conference on Control Science and Systems Engineering, ICCSSE 2016, 27 July 2016 through 29 July 2016 ; 2016 , Pages 82-87 ; 9781467398725 (ISBN) Pourebrahim, M ; Selk Ghafari, A ; Pourebrahim, M ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2016
    Abstract
    During the past decade, Electro-Hydraulic system has performed a significant role in industrial engineering as an actuator for high performance and precision positioning applications. In this case, many control methods have been developed for an electro-hydraulic actuated clutch. In this paper a Linear Quadratic Regulators (LQR) is proposed to trajectory control of a wet clutch actuated by a hydraulic servo valve mechanism. Simulation study was performed using linearized mathematical model of the system implemented in MATLAB software. Based on the simulation results performance of the proposed controller was evaluated and discussed  

    A novel 3-dimentional ultra high precision positioning platform for micro machining cutting tools

    , Article 3rd International Conference on Control, Automation and Robotics, ICCAR 2017, 22 April 2017 through 24 April 2017 ; 2017 , Pages 284-288 ; 9781509060870 (ISBN) Zabihollah, A ; Yadegari, A ; Rashidi, D ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2017
    Abstract
    Ultra-high precision machining is proposed by externally actuating the work piece in linear motions in the X-Y plane and linear motion in the Z-axis. To solve the problems in the machining process such as nonlinearity and low repeatability positioning accuracy of machining tools in a larger scale, a novel platform for cutting tools in micro machining based on electrostatic linear micromotors and piezoelectric stack actuator system is presented. © 2017 IEEE  

    Automatic extraction of is-a relations in taxonomy learning

    , Article 13th International Computer Society of Iran Computer Conference on Advances in Computer Science and Engineering, CSICC 2008, Kish Island, 9 March 2008 through 11 March 2008 ; Volume 6 CCIS , 2008 , Pages 17-24 ; 18650929 (ISSN); 3540899847 (ISBN); 9783540899846 (ISBN) Neshati, M ; Abolhassani, H ; Fatemi, H ; Sharif University of Technology
    2008
    Abstract
    Taxonomy learning is a prerequisite step for ontology learning. In order to create a taxonomy, first of all, existing 'is-a' relations between words should be extracted. A known way to extract 'is-a' relations is finding lexicosyntactic patterns in large text corpus. Although this approach produces results with high precision but it suffers from low values of recall. Furthermore developing a comprehensive set of patterns is tedious and cumbersome. In this paper, firstly, we introduce an approach for developing lexico-syntactic patterns automatically using the snippets of search engine results and then, challenge the law recall of this approach using a combined model, which is based on... 

    A hybrid fuzzy adaptive tracking algorithm for maneuvering targets

    , Article 2008 IEEE International Conference on Fuzzy Systems, FUZZ 2008, Hong Kong, 1 June 2008 through 6 June 2008 ; 2008 , Pages 1869-1873 ; 10987584 (ISSN) ; 9781424418190 (ISBN) Dehghani Tafti, A ; Sadati, N ; Sharif University of Technology
    2008
    Abstract
    A new hybrid fuzzy adaptive algorithm for tracking maneuvering targets is proposed in this paper. The algorithm is implemented with fuzzy inference system (FIS) and current statistical model and adaptive Altering (CSMAF). The CSMAF algorithm is one of most effective methods for tracking the maneuvering targets. It has a higher precision in tracking the maneuvering targets with larger accelerations while it has a lower precision in tracking the maneuvering targets with smaller acceleration. In the proposed algorithm, to overcome the disadvantage of the CSMAF algorithm, the covariance of process noise CSMAF is adjusted adaptively by the output of a FIS. The input of the FIS is discrepancy of... 

    Design and Fabrication of a XY Nano-Positioning System

    , M.Sc. Thesis Sharif University of Technology Nejati, Mohammad Reza (Author) ; Nejat Pishkenari, Hossein (Supervisor)
    Abstract
    Nanopositioning is technology of positioning & manipulation of Nano-scale object. This technology can be considered as one of the fundamental necessities in Nano & Micro research and fabrication and made lots of unbelievable advancement in researches and technologies. There are lots of mechanical systems designed for large scale positioning with sub millimeter resolution, but when it’s come to Nano scale, the range of access should be limited to some micrometer. Also in Nano-scale motion some difficulties like backlash, stick-slip and friction is phenomenon. For increasing the workspace using coarse and fine positioning systems may be an appropriate method. In this method a fine positioning... 

    Zero-power mismatch-independent Digital to Analog converter

    , Article Conference Proceedings - 13th IEEE International NEW Circuits and Systems Conference, NEWCAS 2015, 7 June 2015 through 10 June 2015 ; June , 2015 , Page(s): - 4 ; 9781479988938 (ISBN) Khorami, A ; Sendi, M. S. E ; Nikoofard, A ; Sharifkhani, M ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2015
    Abstract
    A new switched-capacitor Digital to Analog converter (DAC) is presented. In this method, a ladder of series capacitors is used to generate the output voltage levels. A correction phase is used to increase the precision of the DAC. It is analytically shown that the proposed DAC is mismatch and process independent by virtue of the correction phase. That is after some correction phases, the effect of mismatch on the reference voltage levels on the ladder diminishes and an accurate voltage division is provided. It is proven that the whole process sinks no extra charge from the power supply  

    The wide-open three-legged parallel robot for long-bone fracture reduction

    , Article Journal of Mechanisms and Robotics ; Volume 9, Issue 1 , 2017 ; 19424302 (ISSN) Abedinnasab, M. H ; Farahmand, F ; Gallardo Alvarado, J ; Sharif University of Technology
    American Society of Mechanical Engineers (ASME)  2017
    Abstract
    Robotic reduction of long bones is associated with the need for considerable force and high precision. To balance the accuracy, payload, and workspace, we have designed a new six degrees-offreedom three-legged wide-open robotic system for long-bone fracture reduction. Thanks to the low number of legs and their nonsymmetrical configuration, the mechanism enjoys a unique architecture with a frontally open half-plane. This facilitates positioning the leg inside the mechanism and provides a large workspace for surgical maneuvers, as shown and compared to the well-known Gough-Stewart platform. The experimental tests on a phantom reveal that the mechanism is well capable of applying the desired... 

    Orbit Design and Optimization of Regional Navigation Satellite Constellation

    , M.Sc. Thesis Sharif University of Technology Sharif Ahmadian, Alireza (Author) ; Assadian, Nima (Supervisor)
    Abstract
    In this thesis, optimum set of satellite constellations for regional navigation has been investigated. The cost function is the required multiple coverage for navigation in the Iran region with the lowest possible positioning error. In the satellite navigation systems the GDOP (Geometric Dilution of Precision) is a quantitative measure which is usually used to determine the effect of satellites’ orbits geometry on position error estimation. The lower the GDOP, the more precise the navigation would be. In fact, GDOP relates computed satellite-receiver range error to position estimation error. This thesis has two major parts; modeling and optimization. In the modeling of the problem,... 

    An Efficient Model For Considering the Effects Of Drug On Cancer Cells

    , M.Sc. Thesis Sharif University of Technology Nikahd, Mojtaba (Author) ; Habibi, Jafar (Supervisor)
    Abstract
    The development of technologies and some defects in medicine caused to emerge a new approach called precision medicine. Unlike the traditional medicine, medical experts do best treatment for each patient based on his genetic characteristics in this approach. Predicting drug response on cancer cell lines is one of the most vital challenges in this area. Various approaches have been proposed to construct predicting models while the substantial distinctions between resistant and sensitive cell lines had been neglected in them. Here, we propose a new approach for constructing the predictive model. In our approach, we utilized the distinctions between sensitive and resistant cell lines and also... 

    Design and Fabrication of a Flexure-Based Nano-Precision XY Positioning Stage

    , M.Sc. Thesis Sharif University of Technology Darki, Ali Akbar (Author) ; Zohoor, Hassan (Supervisor)
    Abstract
    Nanopositioning is a technology for moving a target object within nanometer (10-9 meter) resolution. Nowadays nanopositioning stages have emerged as an important technological advancement in hi-tech applications, including scanning probe microscopy, lithography, nanometrology, fabrication and assembly of nanostructures and beam steering for optical communication systems. To achieve nanometer resolution the stage must focus on a few tens of micrometers travel range. The combination of piezoelectric actuators and monolithic compliant mechanisms can provide a smooth motion without friction, wear, and backlash. So, piezo-driven compliant mechanisms are used widely in nanopositioning systems. The... 

    Naturality of network creation games, measurement and analysis

    , Article Proceedings of the 2012 IEEE/ACM International Conference on Advances in Social Networks Analysis and Mining, ASONAM 2012 ; 2012 , Pages 716-717 ; 9780769547992 (ISBN) Beyhaghi, H ; Fahmi, Z ; Fazli, M ; Habibi, J ; Jalaly, P ; Safari, M ; Sharif University of Technology
    2012
    Abstract
    Modeling is one of the major research areas in social network analysis whose goal is to study networks structure and its evolution. Motivated by the intuition that members in social networks behave selfishly, network creation games have been introduced for modeling social networks. In this paper, our aim is to measure how much the output graphs of a given network creation game are compatible with a social network. We first show that the precise measurement is not possible in polynomial time. Then we propose a method for its approximation; finally, we show the usability of our method by conducting experiments on real network data  

    Extended convexity of quantum Fisher information in quantum metrology

    , Article Physical Review A - Atomic, Molecular, and Optical Physics ; Volume 91, Issue 4 , April , 2015 ; 10502947 (ISSN) Alipour, S ; Rezakhani, A. T ; Sharif University of Technology
    American Physical Society  2015
    Abstract
    We prove an extended convexity for quantum Fisher information of a mixed state with a given convex decomposition. This convexity introduces a bound which has two parts: (i) The classical part associated with the Fisher information of the probability distribution of the states contributing to the decomposition, and (ii) the quantum part given by the average quantum Fisher information of the states in this decomposition. Next we use a non-Hermitian extension of a symmetric logarithmic derivative in order to obtain another upper bound on quantum Fisher information, which helps to derive a closed form for the bound in evolutions having the semigroup property. We enhance the extended convexity... 

    A self-synchronized chaotic image encryption scheme

    , Article Signal Processing: Image Communication ; Volume 36 , August , 2015 , Pages 106-114 ; 09235965 (ISSN) Daneshgar, A ; Khadem, B ; Sharif University of Technology
    Elsevier  2015
    Abstract
    Abstract In this paper, a word based chaotic image encryption scheme for gray images is proposed that can be used in both synchronous and self-synchronous modes. The encryption scheme operates in a finite field where we have also analyzed its performance according to numerical precision used in implementation. We show that the scheme not only passes a variety of security tests, but also it is verified that the proposed scheme operates faster than other existing schemes of the same type even when using lightweight short key sizes  

    Using an all-speed method to predict high frequency pressure spikes of water hammer with column separation

    , Article 13th International Energy Conversion Engineering Conference, IECEC 2015, 27 July 2015 through 29 July 2015 ; July , 2015 ; 9781624103766 (ISBN) Darbandi, M ; Beige, A. A ; Schneider, G. E ; Sharif University of Technology
    American Institute of Aeronautics and Astronautics Inc, AIAA  2015
    Abstract
    To extend a procedure to ensure the safe operation of a water reactor, we develop a numerical method to compute the high frequency pressure spikes of water hammer with liquid column separation in pipes. In this regard, we first extend a finite-volume all-speed method to solve the full one-dimensional Navier-Stokes equations. This method is capable of simulating gas and liquid phases as well as the vapor-liquid one. On the other hand, the current extended method should be capable of capturing high frequency pressure spikes, which are formed due to water hammer and column separation in pipes. The existence of such high frequency spikes has been recently reported experimentally by other... 

    Dynamic analysis of an a-shaped piezo-actuated walking microrobot

    , Article ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE), 12 November 2010 through 18 November 2010, Vancouver, BC ; Volume 10 , 2010 , Pages 161-170 ; 9780791844472 (ISBN) Kamali Eigoli, A ; Vossoughi, G ; Sharif University of Technology
    2010
    Abstract
    In this paper, a novel, A-shaped microrobot with nanometric resolution for precision positioning applications is addressed. The locomotion concept of the mechanism is founded on the "friction drive principle". To achieve the translational motion, a stack piezoelectric actuates the microrobot near its natural frequency. The dynamic modeling of the mechanism is based on the assumptions of linear behavior of piezo stack actuator and Coulomb friction model at contact points. The suitability of three simple, friction-based locomotion modes for implementation on the proposed device is presented. Influences of different friction coefficients on the behavior of the microrobot, with respect to... 

    A procedure for the design of wideband slant-polarized shaped reflector antennas using a PO-based near field analysis method

    , Article Asia-Pacific Microwave Conference, APMC 2015, 6 December 2015 through 9 December 2015 ; Volume 1 , 2016 ; 9781479987658 (ISBN) Bagheri Korani, E ; Ahmadi Boroujeni, M ; Mohammadpour Aghdam, K ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2016
    Abstract
    A novel approach for the design of wideband doubly curved shaped reflector antennas is introduced. By assuming a virtual aperture in front of the feed antenna and using a PObased near-field method, a fast and precise method for the design of doubly curved shaped reflector antennas is introduces. To prove the effectiveness of method, a 3-15 GHz prototype is fabricated and tested. © IEEE  

    Control of the swiss free electron laser: methods for precision control of pulsed-mode accelerator beams

    , Article IEEE Control Systems ; Volume 37, Issue 6 , 2017 , Pages 30-51 ; 1066033X (ISSN) Rezaeizadeh, A ; Schilcher, T ; Smith, R. S ; Sharif University of Technology
    Abstract
    Free electron laser (FEL) machines generate highpower, coherent, and tunable radiation in the X-ray range. They are used to study molecular structural and dynamic processes at the Ångstrom-femtosecond spatiotemporal scale. The Swiss Free Electron Laser (SwissFEL) facility-under development at the Paul Scherrer Institut and scheduled to begin operation in 2017- will generate intense and short pulses of X-ray light, enabling researchers to observe extremely fast processes, such as the creation of new molecules in chemical reactions or to study the detailed structure of proteins. This article introduces FEL technology from a control systems perspective and provides insight into the types of...