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izadi-yazdan-abadi--nosrat
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Fabrication of Nano Sensor for Detecting H2S
, M.Sc. Thesis Sharif University of Technology ; Soltanieh, Mohammad (Supervisor) ; Rashidi, Alimorad (Supervisor) ; Izadi Yazdan Abadi, Nosrat (Co-Advisor)
Abstract
Due production and use of large amount of chemical and emissions of pollutants in air, detection and control of these compounds are necessary. One of the common methods to detect these pollutants in the ambient is using metal oxide semiconductor sensors. However, these types of sensors suffer from low selectivity toward a certain compound in the mixture of different gas components. In this study, the object was to investigate the effect of different amount of CNTs on performance of tin oxide to improve their selectivity for detection of 50 ppm of hydrogen sulfide at low temperature. To perform the study, nanoparticles of pure tin oxide and SnO2 base hybrids containing 0.25wt%, 0.5wt%, 2.5wt%...
Modeling an Inventory-queueing System for a Producer-retailer System with a Special (r,Q) Inventory Control Policy and Exponential Leadtime
, M.Sc. Thesis Sharif University of Technology ; Mahlooji, Hashem (Supervisor)
Abstract
This thesis covers the problem of a 2-echolen inventory system including a producer and retailer. Producer makes each part and stores it in its own warehouse which is capable of holding as many as S parts. Time that takes for the producer to produce each part is described by an exponential distribution with a fixed rate. Retailer which has its own warehouse with capacity R sees customers arriving with a Poisson distribution. If either of retailer or producer is out of inventory, system does not accept new customers and it is a lost sale, otherwise the customer is served. Whenever retailer runs out of stock, it places an order of size R. producer then looks at its own inventory, if possible a...
General bounds for the optimal value of retailers' reorder point in a two-level inventory control system with and without information sharing
, Article International Journal of Advanced Manufacturing Technology ; Volume 48, Issue 1-4 , April , 2010 , Pages 383-393 ; 02683768 (ISSN) ; Eshragh Jahromi, A ; Akhavan Niaki, S ; Sharif University of Technology
2010
Abstract
In this study, an inventory system consisting of a single product, one supplier, and multiple identical retailers is considered. Each retailer replenishes inventory from the supplier according to the well known (R,Q) policy. Transit times are constant and retailers face independent Poisson demand. The supplier utilizing the retailers' information in decision making for replenishment policy with a given order size starts with m initial batches (of size Q) and places an order in a batch of size Q to an outside source when a new order is placed. In this inventory system, excess demand is backordered, delayed orders are satisfied on a first-come first-serve basis, and no partial shipment is...
An efficient procedure for computing an optimal (R, Q) policy in continuous review systems with poisson demands and constant lead time
, Article Scientia Iranica ; Volume 16, Issue 2 E , 2009 , Pages 128-137 ; 10263098 (ISSN) ; Eshraghnia Jahromi, A ; Modarres Yazdi, M ; Sharif University of Technology
2009
Abstract
In this paper, a continuous review inventory system is considered in which an order in a batch of size Q is placed immediately after the inventory position reaches R. Transportation time is constant and demands are assumed to be generated by a stationary Poisson process with one unit demand at a time. Demands not covered immediately from the inventory are backordered. In a recent paper, the exact evaluation of batch-ordering policies for two-level inventory systems was derived. This evaluation is based on a recursive procedure for determining the exact policy costs in case of one-for-one replenishment policies. In this paper, we show how this result can be applied to find the optimal...
Determination of the Optimal Policy in a Two Level Inventory System, Using Information Sharing, with a Different Order Size
, Ph.D. Dissertation Sharif University of Technology ; Eshraghniaye Jahromi, Abdolhamid (Supervisor)
Abstract
To coordinate between different echelons in supply chains, it is necessary to analyze the multi-echelon inventory systems. Access to advanced technologies in Information Technology make some changes in the inventory management in these systems. Theses technologies that were gradually got inexpensive are attractive for researchers of the multi-echelon inventory systems. Using theses technologies, the information that leads to costs reduction in a supply chain is accessible economically. In this thesis, first efficient solutions for Base Stock and Reorder point, Quantity of order policies will be derived. Then, a serial two-level supply chain comprised of one retailer and one supplier will be...
Study of Melting and Rapid Solidification of TiAl alloy and Formation of its Diffusion Bonded Structure using Molecular Dynamics Simulation
, M.Sc. Thesis Sharif University of Technology ; Aashuri, Hossin (Supervisor) ; Simchi, Abdolreza (Co-Advisor)
Abstract
The rapid pace of development of nanoscience and nanotechnology and their applications in various fields have made the study of materials in smaller scales more important than any time ever. Having an insight of materials’ microstructure and the mechanism of different phenomena in the atomic scale will be very beneficent in designing new and advanced materials or modifying the current manufacturing processes. Since molecular dynamics (MD) method has been well known as a mean of studying materials in atomic scale, it has been used in this study to investigate two different phenomena. The selection of the appropriate interatomic potential is of great importance in MD; Embedded Atom Method...
An adaptive filter for noise cancelling in mammography images based on Cellular Automata
, Article International Review on Modelling and Simulations ; Volume 5, Issue 3 , June , 2012 , Pages 1322-1326 ; 19749821 (ISSN) ; Masoumzadeh Tork, A ; Yazdan Talab, E ; Ramezanpour, H ; Darmani, G ; Sharif University of Technology
2012
Abstract
In recent years, several techniques based on repetition of the image are used to remove noise. In this paper a new method based on Cellular Automata for image noise removal in mammography images is recommended. We present a new formulation that makes improvements. The formulation uses a neighborhood with sizes and format adapted to the features of the image on reconstruction. We demonstrated through experiments and comparison with other common used techniques that this procedure produces excellent results for the problem of restoring true color images
Optimization of nonlinear unbalanced flexible rotating shaft passing through critical speeds
, Article International Journal of Structural Stability and Dynamics ; Volume 22, Issue 1 , 2022 ; 02194554 (ISSN) ; Rokn Abadi, M ; Firouz Abadi, R. D ; Sharif University of Technology
World Scientific
2022
Abstract
This work studies the nonlinear oscillations of an elastic rotating shaft with acceleration to pass through the critical speeds. A mathematical model incorporating the Von-Karman higher-order deformations in bending is developed to investigate the nonlinear dynamics of rotors. A flexible shaft on flexible bearings with springs and dampers is considered as rotor system for this work. The shaft is modeled as a beam and the Euler-Bernoulli beam theory is applied. The kinetic and strain energies of the rotor system are derived and Lagrange method is then applied to obtain the coupled nonlinear differential equations of motion for 6 degrees of freedom. In order to solve these equations...
Nonlinear responses of unbalanced flexible rotating shaft passing through critical speeds
, Article Meccanica ; 2021 ; 00256455 (ISSN) ; Rokn Abadi, M ; Firouz Abadi, R.D ; Mehralian, F ; Sharif University of Technology
Springer Science and Business Media B.V
2021
Abstract
This work studies the nonlinear oscillations of an elastic rotating shaft with acceleration to pass through the critical speeds. A mathematical model incorporating the Von-Karman higher-order deformations in bending is developed and analyzed to investigate the nonlinear dynamics of rotors. A flexible shaft on flexible bearings with springs and dampers is considered as rotor system for the present work. The shaft is modeled as a beam with a circular cross-section and the Euler Bernoulli beam theory is applied. The kinetic and strain energies of the rotor system are derived and Lagrange method is then applied to obtain the coupled nonlinear differential equations of motion for 6° of freedom....
Failure-based equivalence of constraint automata
, Article International Journal of Computer Mathematics ; Volume 87, Issue 11 , 2010 , Pages 2426-2443 ; 00207160 (ISSN) ; Movaghar, A ; Sharif University of Technology
2010
Abstract
Constraint automata are the first-proposed operational semantics of Reo coordination language. They can be composed not only by all well-defined composition operators of labeled transition systems but also by two new operators. The new operators are joining of constraint automata with respect to their common port names and hiding a port name in all transition labels. The operations of these two extra operators depend on the internal structures of the transition labels, while in the others each transition label is considered as a simple entity. An equivalence relation between transition systems is a congruence relation if the replacement of the components of a model by the equivalent ones...
Compositional failure-based equivalence of constraint automata
, Article Electronic Notes in Theoretical Computer Science ; Volume 250, Issue 1 , 2009 , Pages 105-122 ; 15710661 (ISSN) ; Movaghar, A ; Sharif University of Technology
2009
Abstract
Reo is a coordination language for modeling component connectors of component-based computing systems. Constraint automaton, as an extension of finite automaton, has been proposed as the operational semantics of Reo. In this paper, we introduce an extended definition of constraint automaton by which, every constraint automaton can be considered as a labeled transition system and each labeled transition system can be translated into a constraint automaton. We show that failure-based equivalences CFFD and NDFD are congruences with respect to composition of constraint automata using their join (production) and hiding operators. Based on these congruency results and by considering the temporal...
Financial risk constrained remote controlled switch deployment in distribution networks
, Article IET Generation, Transmission and Distribution ; Volume 12, Issue 7 , 2018 , Pages 1547-1553 ; 17518687 (ISSN) ; Safdarian, A ; Sharif University of Technology
Institution of Engineering and Technology
2018
Abstract
Recently, diverse technologies and apparatus are launched to enhance service reliability in the distribution level. In this regard, remote controlled switches (RCSs) can play a prominent role in declining interruption durations and costs. The stochastic nature of contingencies, however, imposes considerable uncertainty on the achievements of RCS deployment. This study presents a model to consider the financial risk induced by the uncertainty in an RCS placement problem. The risk awareness of distribution companies is scrutinised through an effective risk measure, i.e. conditional value at risk. In the model, the number and location of RCSs are determined such that the system expected cost is...
Financial risk evaluation of RCS deployment in distribution systems
, Article IEEE Systems Journal ; 2018 ; 19328184 (ISSN) ; Safdarian, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
Remote controlled switch deployment in distribution networks is usually justified via comparing the required investment with the expected decrease in interruption costs. Although the investment is known prior to the implementation, the stochastic nature of contingencies imposes significant uncertainty on interruption costs. The uncertainty may impose substantial financial risks on the distribution company. This paper aims at evaluating the financial risk and key affecting parameters. For doing so, a step-by-step method is presented to evaluate the risk. The method captures the stochastic nature of contingencies through a sequential Monte Carlo simulation approach. A mathematical formulation...
A MIP model for risk constrained switch placement in distribution networks
, Article IEEE Transactions on Smart Grid ; Volume 10, Issue 4 , 2019 , Pages 4543-4553 ; 19493053 (ISSN) ; Safdarian, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
The great share of interruptions in distribution networks motivates distribution decision makers to establish various reliability enhancement strategies. Amongst these strategies, deploying remote controlled switch (RCS) can make a crucial contribution to the reduction of interruption costs. Nevertheless, the stochastic nature of contingencies affects RCS worth and imposes substantial financial risk to RCS deployment projects. This paper proposes a mathematical model to consider the risk in the optimal RCS deployment problem. The model determines the number and location of RCSs such that the expected profit is maximized while financial risk is minimized. The risk is modeled through...
Electrowetting of power-law fluids in microgrooved channels
, Article Physics of Fluids ; Volume 32, Issue 7 , July , 2020 ; Moosavi, A ; Sharif University of Technology
American Institute of Physics Inc
2020
Abstract
Studying the dynamic behavior of droplets is of great importance in the electrowetting phenomena. However, despite the widespread use of non-Newtonian fluids in industry and daily life including medicine, food, petroleum, environmental biomass, and lab on a chip, most studies have focused on Newtonian fluids. In this study, a power-law fluid is considered as a typical example of non-Newtonian fluids and its dynamic behavior is investigated within a microchannel, and the results are compared with those of the Newtonian fluids. Both the grooved and non-grooved substrates are considered. For this purpose, the governing equations for the two phase fluid flow are solved using the finite element...
A MIP model for risk constrained switch placement in distribution networks
, Article IEEE Transactions on Smart Grid ; 2018 ; 19493053 (ISSN) ; Safdarian, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
The great share of interruptions in distribution networks motivates distribution decision makers to establish various reliability enhancement strategies. Amongst, deploying remote controlled switch (RCS) can make a crucial contribution to the reduction of interruption costs. Nevertheless, the stochastic nature of contingencies affects the RCS worth and imposes substantial financial risk to RCS deployment projects. This paper proposes a mathematical model to consider the risk in the optimal RCS deployment problem. The model determines the number and location of RCSs such that the expected profit is maximized while financial risk is minimized. The risk is modeled through conditional...
Financial risk evaluation of RCS deployment in distribution systems
, Article IEEE Systems Journal ; Volume 13, Issue 1 , 2019 , Pages 692-701 ; 19328184 (ISSN) ; Safdarian, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
Remote controlled switch deployment in distribution networks is usually justified via comparing the required investment with the expected decrease in interruption costs. Although the investment is known prior to the implementation, the stochastic nature of contingencies imposes significant uncertainty on interruption costs. The uncertainty may impose substantial financial risks on the distribution company. This paper aims at evaluating the financial risk and key affecting parameters. For doing so, a step-by-step method is presented to evaluate the risk. The method captures the stochastic nature of contingencies through a sequential Monte Carlo simulation approach. A mathematical formulation...
Model checking of component-based systems and coordination models
, Article 5th Doctoral Consortium on Enterprise Information Systems, DCEIS - In Conjunction with the 9th International Conference on Enterprise Information Systems, ICEIS 2007, Madeira, 12 June 2007 through 12 June 2007 ; 2007 , Pages 82-88 ; 9789898111043 (ISBN) ; Movaghar, A ; Sharif University of Technology
2007
Abstract
Reo is an exogenous coordination language for compositional construction of the coordinating subsystem of a component-based software. Constraint automaton is defined as the operational semantics of Reo. The main goal of this work is to prepare a model checking based verification environment for component-based systems, which their component connectors are modeled by Reo networks and Constraint Automata. We use compositional minimization and abstraction methods of model checking for verification of component-based systems and their component connectors modeled by Reo
Compositional failure-based semantic equivalences for Reo specifications
, Article ESEC/FSE 2007: 6th Joint Meeting - Sixth International Workshop on Specification and Verification of Component-Based Systems, SAVCBS 2007, Dubrovnik, 3 September 2007 through 4 September 2007 ; September , 2007 , Pages 99-100 ; 9781595937216 (ISBN) ; Movaghar, A ; Sharif University of Technology
2007
Abstract
Reo is a coordination language for modeling component connectors of component-based computing systems. We show that the failure-based equivalences NDFD and CFFD are congruences with respect to composition operators of Reo. Copyright 2007 ACM
Model checking of component based software using compositional reductions
, Article International Journal of Software Engineering and Knowledge Engineering ; Volume 18, Issue 5 , 2008 , Pages 683-712 ; 02181940 (ISSN) ; Movaghar, A ; Sharif University of Technology
World Scientific Publishing Co. Pte Ltd
2008
Abstract
A component-based computing system consists of two main parts: a set of components and a coordination subsystem. Reo is an exogenous coordination language for compositional construction of the coordination subsystem. Constraint automaton has been defined as the operational semantics of Reo. The main goal of this paper is to prepare a model checking method for verifying linear time temporal properties of component-based systems whose coordinating subsystems are modeled by Reo and components are modeled by labeled transition systems. For this purpose, we introduce modified definitions of constraint automata and their composition operators by which, every constraint automaton can be considered...