Search for: model-based-approach
0.006 seconds

    Hybrid switching control of automotive cold start hydrocarbon emission

    , Article Proceedings of the American Control Conference ; 2013 , Pages 4417-4422 ; 07431619 (ISSN) ; 9781479901777 (ISBN) Salehi, R ; Shahbakhti, M ; Hedrick, J. K ; Sharif University of Technology
    Reduction of cold start hydrocarbon (HC) emission requires a proper compromise between low engine-out HC emission and fast light-off of the three way catalytic converter (TWC). In this paper a model based approach is used to design and optimize a hybrid switching system for reducing HC emission of a mid-sized passenger car during the cold start phase of FTP-75. This hybrid system takes the benefit of increasing TWC temperature during the early stages of the driving cycle by switching between different operational modes. The switching times are optimized to reduce the cumulative tailpipe HC emission of an experimentally validated automotive emission model. It is shown that the new hybrid... 

    Evaluation of endothelial response to reactive hyperaemia in peripheral arteries using a physiological model

    , Article International Journal of Biomedical Engineering and Technology ; Volume 33, Issue 4 , 2020 , Pages 305-324 Parsafar, M. H ; Zahedi, E ; Vahdat, B. V ; Sharif University of Technology
    Inderscience Publishers  2020
    Non-invasive measurement of flow-mediated dilation (FMD) in the brachial artery for assessing endothelial function is costly and operator-dependent, limiting its application to research cases. In this paper, an approach based on a physiological model between normalized central blood pressure and finger photoplethysmogram is presented. Baseline model parameters are estimated using a genetic algorithm in 30 subjects consisting of ten normal blood pressure (BP), ten high-BP and ten elderly volunteers. Beat-to-beat fitness values after reactive hyperaemia are calculated using baseline (before cuff occlusion) data. Results show that stimulus-induced changes are fairly described with a first order... 

    Modeling in-and-out-of-water impact on all-electric ship power system considering propeller submergence in waves

    , Article 2021 IEEE Transportation Electrification Conference and Expo, ITEC 2021, 21 June 2021 through 25 June 2021 ; 2021 , Pages 533-538 ; 9781728175836 (ISBN) Nasiri, S ; Peyghami, S ; Parniani, M ; Blaabjerg, F ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2021
    Despite the advantages of employing an electric propulsion system in All-Electric Ships (AES), additional power fluctuation sources have emerged in the ship power system as a result. Since the propellers are the primary power consumers in the AES, these fluctuations may significantly affect its power system power quality. Thus, for optimal performance of the ship power system, these fluctuations need to be rigorously investigated at the design level of vessels. Waves collision is one of the critical conditions where propellers inject power fluctuations into the ship power system. Therefore, a comprehensive model is essential to analyze the propellers in-and-out-of-water effect on the ship... 

    A comparison between disturbance observer-based and model-based control of needle in percutaneous applications

    , Article IECON Proceedings (Industrial Electronics Conference), 25 October 2012 through 28 October 2012 ; October , 2012 , Pages 2104-2108 ; 9781467324212 (ISBN) Maghsoudi, A ; Jahed, M ; The Institute of Electrical and Electronics Engineers (IEEE); IEEE Industrial Electronics Society (IES) ; Sharif University of Technology
    In this paper, model-based and distrbance observer (DOB)-based control of needle in precautious applications are compared. In the model-based approach, the force acting on the needle is calculated by evaluating the finite element model (FEM) of the tissue with the tissue deformation. In DOB-based method, the force acting on the needle is considered as an external disturbance and it is estimated using position and velocity of the needle. In both approaches, the calculated/estimated force is used in a sliding mode control scheme to steer the needle to the target. A dynamics equation for the movement of the needle is proposed which includes the force applied by the tissue to the needle. The... 

    An approach for refining JML specification to object oriented code

    , Article 2009 14th International CSI Computer Conference, 20 October 2009 through 21 October 2009 ; 2009 , Pages 1-9 ; 9781424442621 (ISBN) Piri, R ; Mirian Hosseinabadi, S. H ; Sharif University of Technology
    JML is a behavioral interface specification language which has Java as its target implementation language. It combines the idea of using Java expressions from Eiffel language with the model-based approach to specify a program. Refinement calculus is a framework to produce executable code from a specification by preserving the correctness of programs. In this paper some constructs of JML concerning object creation, feature call, exceptional behavior and concurrency constructs are studied and some refinement rules are proposed to obtain an object oriented code in Java from a JML specification containig these constructs. The correctness of these rules is proved by weakest precondition predicate... 

    A model-based approach for estimation of changes in lumbar segmental kinematics associated with alterations in trunk muscle forces

    , Article Journal of Biomechanics ; Volume 70 , March , 2018 , Pages 82-87 ; 00219290 (ISSN) Shojaei, I ; Arjmand, N ; Meakin, J ; Bazrgari, B ; Sharif University of Technology
    Elsevier Ltd  2018
    The kinematics information from imaging, if combined with optimization-based biomechanical models, may provide a unique platform for personalized assessment of trunk muscle forces (TMFs). Such a method, however, is feasible only if differences in lumbar spine kinematics due to differences in TMFs can be captured by the current imaging techniques. A finite element model of the spine within an optimization procedure was used to estimate segmental kinematics of lumbar spine associated with five different sets of TMFs. Each set of TMFs was associated with a hypothetical trunk neuromuscular strategy that optimized one aspect of lower back biomechanics. For each set of TMFs, the segmental... 

    Investigation of a hybrid kinematic calibration method for the 'sina' surgical robot

    , Article IEEE Robotics and Automation Letters ; Volume 5, Issue 4 , 2020 , Pages 5276-5282 Alamdar, A ; Samandi, P ; Hanifeh, S ; Kheradmand, P ; Mirbagheri, A. R ; Farahmand, F ; Sarkar, S ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2020
    Calibrating the inverse kinematics of complex robots is often a challenging task. Finding analytical solutions is not always possible and the convergence of numerical methods is not guaranteed. The model-free approaches, based on machine learning and artificial intelligence, are fast and easy to work, however, they need a huge amount of experimental training data to provide acceptable results. In this article, we proposed a hybrid method to benefit the advantage of both model-based and model-free approaches. The forward kinematics of the robot is calibrated using a model-based approach, and its inverse kinematics using a neural network. Hence, while there is no need to solve the nonlinear... 

    Model-based ECG fiducial points extraction using a modified extended Kalman filter structure

    , Article 2008 1st International Symposium on Applied Sciences in Biomedical and Communication Technologies, ISABEL 2008, Aalborg, 25 October 2008 through 28 October 2008 ; December , 2008 ; 9781424426478 (ISBN) Sayadi, O ; Shamsollahi, M. B ; Sharif University of Technology
    This paper presents an efficient algorithm based on a nonlinear dynamical model for the precise extraction of the characteristic points of electrocardiogram (ECG), which facilitates the HRV analysis. Determining the precise position of the waveforms of an ECG signal is complicated due to the varying amplitudes of its waveforms, the ambiguous and changing form of the complex and morphological variations with unknown sources of drift. A model-based approach handles these complications; therefore a method based on the usage of this concept in an extended Kalman filter structure has been developed. The fiducial points are detected using both the parameters of Gaussian-functions of the model, and...