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    Bohmian approach to spin-dependent time of arrival for particles in a uniform field and for particles passing through a barrier

    , Article Journal of Physics A: Mathematical and Theoretical ; Volume 41, Issue 37 , 13 August , 2008 ; 17518113 (ISSN) Mousavi, S. V ; Golshani, M ; Sharif University of Technology
    2008
    Abstract
    The de Broglie-Bohm interpretation of quantum mechanics with and without spin-dependence is used to determine electron trajectories, arrival-time distribution of electrons and the mean arrival time of spin-1/2 particles (including electrons) in the presence of a uniform field and a barrier separately. The difference for the mean arrival times, which are calculated with different guidance equations, is examined versus mass of the arriving particle and versus group velocity of the arriving electron wave packet and also versus the width of the barrier. Numerical calculations show that these differences are of the order of 10-18-10-17 s. Another feature of the modified guidance law is that... 

    An algorithm for geometrical uncertainty analysis in planar truss structures

    , Article Structural and Multidisciplinary Optimization ; Vol. 49, issue. 2 , February , 2014 , pp. 225-238 ; Online ISSN: 1615-1488 Aghabeigi, M ; Movahhedy, M. R ; Sharif University of Technology
    Abstract
    An algorithm is proposed for description of error accumulation during assembly process of planar truss structures. Specifically, given the tolerances of pre-fabricated members, the uncertainty in the position of nodes is calculated in terms of variances and covariances. Twoconstituent elements of planar trusses (i.e. two-bar unit cell and redundant member) are formulated based on linear models of kinematics and deformation mechanics. Subsequently, these models are combined together in a single algorithm to construct a suitable procedure for estimation of uncertainty zone of each node. Accuracy of the developed method is verified by comparing its results with outcomes of Monte Carlo... 

    Exploiting structural information of data in active learning

    , Article Artificial Intelligence and Soft Computing: Lecture Notes in Computer Science ; Volume 8468 LNAI, Issue PART 2 , 2014 , Pages 796-808 Shadloo, Maryam ; Beigy, Hamid ; Haghiri, Siavash ; Sharif University of Technology
    Abstract
    In recent years, the active learning algorithms have focused on combining correlation criterion and uncertainty criterion for evaluating instances. Although these criteria might be useful, applying these measures on whole input space globally may lead to inefficient selected instances for active learning. The proposed method takes advantage of clustering to partition input space to subspaces. Then it exploits both labeled and unlabeled data locally for selection of instances by using a graph-based active learning. We define a novel utility score for selecting clusters by combining uncertainty criterion, local entropy of clusters and the factor of contribution of each cluster in queries.... 

    Forecasting the effects of a Canada-US currency union on output and prices: A counterfactual analysis

    , Article Journal of Forecasting ; Volume 32, Issue 7 , 2013 , Pages 639-653 ; 02776693 (ISSN) Mahdi Barakchian, S ; Sharif University of Technology
    2013
    Abstract
    This paper is a counterfactual analysis investigating the consequences of the formation of a currency union for Canada and the USA: whether outputs increase and prices decrease if these countries form a currency union. We use a two-country cointegrated model to conduct the counterfactual analysis, where the conditional forecasts are generated based on the Gaussian assumption. To deal with structural breaks and model uncertainty, conditional forecasts are generated from different models/estimation windows and the model-averaging technique is used to combine the forecasts. We also examine the robustness of our results to parameter uncertainty using the wild bootstrap method. The results show... 

    Guest editor's comments on special issue on nonuniform sampling

    , Article Sampling Theory in Signal and Image Processing ; Volume 7, Issue 2 , 1 May , 2008 , Pages 109-112 ; 15306429 (ISSN) Marvasti, F ; Sharif University of Technology
    2008

    Quantifying seismic response uncertainty of electrical substation structures using endurance time method

    , Article Structures ; Volume 30 , 2021 , Pages 838-849 ; 23520124 (ISSN) Ghahremani Baghmisheh, A ; Estekanchi, H. E ; Sharif University of Technology
    Elsevier Ltd  2021
    Abstract
    A new procedure is proposed to quantify uncertainties involved in the seismic response of structures including ground motion and modeling variability. The advent of performance-based earthquake engineering (PBEE) and probabilistic seismic risk analysis necessitates consideration of uncertainties in predicting seismic responses. However, the high computational cost of conventional methods restricts their application to only simple numerical models. The present study employs the endurance time (ET) method concept to predict the response distribution which requires much less computational efforts than conventional methods. The proposed procedure for the quantification of record-to-record... 

    On possibilistic and probabilistic uncertainty assessment of power flow problem: A review and a new approach

    , Article Renewable and Sustainable Energy Reviews ; Vol. 37 , 2014 , p. 883-895 ; ISSN: 13640321 Aien, M ; Rashidinejad, M ; Fotuhi-Firuzabad, M ; Sharif University of Technology
    Abstract
    As energy resource planning associated with environmental consideration are getting more and more challenging all around the world, the penetration of distributed energy resources (DERs) mainly those harvesting renewable energies (REs) ascend with an unprecedented rate. This fact causes new uncertainties to the power system context; ergo, the uncertainty analysis of the system performance seems necessary. In general, uncertainties in any engineering system study can be represented probabilistically or possibilistically. When sufficient historical data of the system variables is not available, a probability density function (PDF) might not be defined, while they must be represented in another... 

    A mixed epistemic-aleatory stochastic framework for the optimal operation of hybrid fuel stations

    , Article IEEE Transactions on Vehicular Technology ; Volume 70, Issue 10 , 2021 , Pages 9764-9774 ; 00189545 (ISSN) Faridpak, B ; Farrokhifar, M ; Alahyari, A ; Marzband, M ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2021
    Abstract
    The fast development of technologies in the smart grids provides new opportunities such as co-optimization of multi-energy systems. One of the new concepts that can utilize multiple energy sources is a hybrid fuel station (HFS). For instance, an HFS can benefit from energy hubs, renewable energies, and natural gas sources to supply electric vehicles along with natural gas vehicles. However, the optimal operation of an HFS deals with uncertainties from different sources that do not have similar natures. Some may lack in term of historical data, and some may have very random and unpredictable behavior. In this study, we present a stochastic mathematical framework to address both types of these... 

    A comprehensive review on uncertainty modeling techniques in power system studies

    , Article Renewable and Sustainable Energy Reviews ; Volume 57 , 2016 , Pages 1077-1089 ; 13640321 (ISSN) Aien, M ; Hajebrahimi, A ; Fotuhi Firuzabad, M ; Sharif University of Technology
    Elsevier Ltd 
    Abstract
    As a direct consequence of power systems restructuring on one hand and unprecedented renewable energy utilization on the other, the uncertainties of power systems are getting more and more attention. This fact intensifies the difficulty of decision making in the power system context; therefore, the uncertainty analysis of the system performance seems necessary. Generally, uncertainties in any engineering system study can be represented probabilistically or possibilistically. When sufficient historical data of the system variables is not available, a probability density function (PDF) might not be defined, they must be represented in another manner i.e. using possibilistic theory. When some... 

    Design and implementation of an online precise monitoring and performance analysis system for centrifugal pumps

    , Article IEEE Transactions on Industrial Electronics ; 2017 ; 02780046 (ISSN) Emami, S. A ; Emami, M. H ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2017
    Abstract
    Development of design and production technology of centrifugal pumps for achieving better performance and less energy consumption in these devices has increasingly been taken into consideration. This is due to the fact that centrifugal pumps have an important contribution in industrial applications and energy consumption around the world. Accordingly, the international standards of centrifugal pumps, urge more precise analysis systems for obtaining the performance curves of these pumps. For this reason, a complete, precise and real-time monitoring and performance analysis system for centrifugal pumps is introduced in this paper. The pump characteristics are measured by precise measuring... 

    A new model for robust facility layout problem [electronic resource]

    , Article Information Sciences, Elsevier ; Volume 278, 10 September 2014, Pages 498–509 Neghabi, H. (Hossein) ; Eshghi, Kourosh ; Salmani, Mohammad Hassan ; Sharif University of Technology
    Abstract
    The Facility Layout Problem (FLP) is the problem of locating each department in a long plant floor without any overlap between departments in order to minimize the material handling cost. The main purpose of this study is to show the effectiveness of a robust approach to solve FLP. In this study, it is assumed that the departments’ length and width are not predetermined. For modeling this kind of uncertainty, the size of each department is considered as a bounded variable and two new parameters are also introduced to implement a robust approach. Moreover, a new adaptive algorithm is designed to determine the robust layout with respect to the decision makers’ requirements. Furthermore, the... 

    Obstacles on the Way Toward an Entropic Uncertainty Relation

    , Article International Journal of Theoretical Physics ; 2013 , Pages 1-10 ; 00207748 (ISSN) Khatam, I ; Shafiee, A ; Sharif University of Technology
    2013
    Abstract
    Deutsch's entropic uncertainty relation is examined by using two experiments in which the spin of a single spin-half particle is detected after passing through two Stern-Gerlach apparatuses in two successive times. Two experiments differ only in the angle settings of the Stern-Gerlach apparatuses. In the general case where the angles are arbitrarily arranged, Deutsch's inequality is violated  

    Position-momentum uncertainty relation for an open macroscopic quantum system

    , Article Journal of Statistical Physics ; Volume 165, Issue 6 , 2016 , Pages 1141-1152 ; 00224715 (ISSN) Naeij, H. R ; Shafiee, A ; Sharif University of Technology
    Springer New York LLC 
    Abstract
    The macroscopic quantum systems are considered as a bridge between quantum and classical systems. In this study, we explore the validity of the original Heisenberg position–momentum uncertainty relation for a macroscopic harmonic oscillator interacting with environmental micro-particles. Our results show that, in the quasi-classical situation, the original uncertainty relation does not hold, when the number of particles in the environment is small. Nonetheless, increasing the environmental degrees of freedom removes the violation bounds in the regions of our investigation  

    Position–momentum uncertainty relation for an open macroscopic quantum system

    , Article Journal of Statistical Physics ; 2016 , Pages 1-12 ; 00224715 (ISSN) Naeij, H. R ; Shafiee, A ; Sharif University of Technology
    Springer New York LLC  2016
    Abstract
    The macroscopic quantum systems are considered as a bridge between quantum and classical systems. In this study, we explore the validity of the original Heisenberg position–momentum uncertainty relation for a macroscopic harmonic oscillator interacting with environmental micro-particles. Our results show that, in the quasi-classical situation, the original uncertainty relation does not hold, when the number of particles in the environment is small. Nonetheless, increasing the environmental degrees of freedom removes the violation bounds in the regions of our investigation  

    Proposing an optimum model for time estimation of construction projects in Iranian gas refineries

    , Article Engineering Journal ; Volume 21, Issue 5 , 2017 , Pages 285-304 ; 01258281 (ISSN) Naderpour, A ; Majrouhi Sardroud, J ; Mofid, M ; Sharif University of Technology
    Abstract
    Time management can be effective in a project when the project schedule is based on comprehensive time scheduling. In the industries with complicated processes, many uncertainties and risks affect the timing of projects. Considering the very low reliability of the project planning in certainty-based approach, using more secure models for control and interact with uncertainty should be placed on the agenda. Iranian Gas Company has been using risk management to manage probable uncertainties in construction projects but in the field of possible uncertainties, actions are very scarce. This article aims to propose an optimum model based on the integrated risk management and fuzzy expert systems... 

    H ∞ and μ synthesis control of virtual structure satellites formation flying

    , Article International Journal of Dynamics and Control ; Volume 5, Issue 3 , 2017 , Pages 741-755 ; 2195268X (ISSN) Hassani, A ; Saghafi, F ; Pasand, M ; Sharif University of Technology
    Abstract
    Recent developments in the space industry and the great tendency to define efficient, precise and low cost missions are the main reasons for the growing interest in satellites formation flight. Regarding the aforementioned, the study of multiple satellites control methods is the subject of the present paper. In this paper, two linear robust control strategies are applied to position control system of certain satellites in the virtual structure formation flight. The proposed controllers are designed considering different parametric uncertainties such as semimajor axis and eccentricity changes as well as some disturbances like second term of gravitational acceleration function (j2) and drag... 

    Reconfiguring a set of coverage-providing facilities under travel time uncertainty

    , Article Socio-Economic Planning Sciences ; 2017 ; 00380121 (ISSN) Berman, O ; Hajizadeh, I ; Krass, D ; Rahimi Vahed, A ; Sharif University of Technology
    Elsevier Ltd  2017
    Abstract
    We study networks of facilities that must provide coverage under conditions of uncertainty with respect to travel times and customer demand. We model this uncertainty through a set of scenarios. Since opening new facilities and/or closing existing ones is often quite expensive, we focus on optimal re-configuration of the network, that is finding a facility set that achieves desired thresholds with respect to expected and minimal coverage, while retaining as many of the existing facilities as possible. We illustrate our model with an example of Toronto Fire Service. We demonstrate that relocating just a few facilities can have the same effect as opening a similar number of new ones. We... 

    Probabilistic hierarchical bayesian framework for time-domain model updating and robust predictions

    , Article Mechanical Systems and Signal Processing ; 2018 ; 08883270 (ISSN) Sedehi, O ; Papadimitriou, C ; Katafygiotis, L. S ; Sharif University of Technology
    Abstract
    A new time-domain hierarchical Bayesian framework is proposed to improve the performance of Bayesian methods in terms of reliability and robustness of estimates particularly for uncertainty quantification and propagation in structural dynamics. The proposed framework provides a reliable approach to account for the variability of the inference results observed when using different data sets. The proposed formulation is compared with a state-of-the-art Bayesian approach using numerical and experimental examples. The results indicate that the hierarchical Bayesian framework provides a more realistic account of the uncertainties, whereas the non-hierarchical Bayesian approach severely... 

    Probabilistic hierarchical bayesian framework for time-domain model updating and robust predictions

    , Article Mechanical Systems and Signal Processing ; Volume 123 , 2019 , Pages 648-673 ; 08883270 (ISSN) Sedehi, O ; Papadimitriou, C ; Katafygiotis, L. S ; Sharif University of Technology
    Academic Press  2019
    Abstract
    A new time-domain hierarchical Bayesian framework is proposed to improve the performance of Bayesian methods in terms of reliability and robustness of estimates particularly for uncertainty quantification and propagation in structural dynamics. The proposed framework provides a reliable approach to account for the variability of the inference results observed when using different data sets. The proposed formulation is compared with a state-of-the-art Bayesian approach using numerical and experimental examples. The results indicate that the hierarchical Bayesian framework provides a more realistic account of the uncertainties, whereas the non-hierarchical Bayesian approach severely... 

    Development of H ∞ -Robust control strategy for drying process in fluidized food bed dryers

    , Article Iranian Journal of Science and Technology - Transactions of Mechanical Engineering ; Volume 43, Issue 1 , 2019 , Pages 87-101 ; 22286187 (ISSN) Moradi, H ; Ghabraei, S ; Vossoughi, G ; Sharif University of Technology
    Springer International Publishing  2019
    Abstract
    Moisture control of food products is of great importance in drying processes. Improving the dryer control system results in consistent production and reduction in energy consumption. In this paper, a state observer is used to estimate the moisture content and other state variables online. Estimated states are used in a control system including the regulator for disturbance rejection and robust controller for tracking objective. Since the bed dryer mechanism is a multivariable complex system associated with various uncertainties, a realistic uncertain model is considered. Moisture content and temperature of tea leaves (or other food products) are controlled at desired set points by...