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Balancing public bicycle sharing system using inventory critical levels in queuing network
, Article Computers and Industrial Engineering ; Volume 141 , March , 2020 ; Mahdavi, I ; Mahdavi Amiri, N ; Khorram, E ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Public Bicycle Sharing System has recently been developed and installed in many cities as a workable and popular transportation system. There are still some noticeable challenges associated with the operation of the system, like responding to all renting requests and all demands of vacant docks for returning bikes. Balancing the inventory of stations is necessary to minimize the rejected demands of bikes and the empty lockers. Here, critical levels are defined to control requests of different routes in which a demand of a specified destination is accepted if the inventory of the original station is higher than the route's critical level. The capacity of stations and the fleet size are...
A single-retailer multi-supplier multi-product inventory model with destructive testing acceptance sampling and inflation
, Article Journal of Industrial and Production Engineering ; September , 2018 ; 21681015 (ISSN) ; Akhavan Niaki, S. T ; Farhangi, M ; Mahdavi, I ; Sharif University of Technology
Taylor and Francis Ltd
2018
Abstract
In this paper, a multi-product inventory problem is investigated in which a retailer buys items from different suppliers based on their purchasing costs and defective rates. Due to the warehouse and staff constraints involved, the inventory cycle consists of two parts. The first part corresponds to a screening period in which a destructive testing acceptance-sampling plan is used to accept or reject a lot. The other part is for selling the items. In the screening period, a lot that is rejected is returned to the suppliers where another lot is claimed for substitution at no cost. Shortage occurs during the screening period and the defective items are sold at a lower price at the end of the...
A single-retailer multi-supplier multi-product inventory model with destructive testing acceptance sampling and inflation
, Article Journal of Industrial and Production Engineering ; Volume 36, Issue 6 , 2019 , Pages 351-361 ; 21681015 (ISSN) ; Akhavan Niaki, S. T ; Farhangi, M ; Mahdavi, I ; Sharif University of Technology
Taylor and Francis Ltd
2019
Abstract
In this paper, a multi-product inventory problem is investigated in which a retailer buys items from different suppliers based on their purchasing costs and defective rates. Due to the warehouse and staff constraints involved, the inventory cycle consists of two parts. The first part corresponds to a screening period in which a destructive testing acceptance-sampling plan is used to accept or reject a lot. The other part is for selling the items. In the screening period, a lot that is rejected is returned to the suppliers where another lot is claimed for substitution at no cost. Shortage occurs during the screening period and the defective items are sold at a lower price at the end of the...
Speed limit of quantum metrology
, Article Scientific Reports ; Volume 13, Issue 1 , 2023 ; 20452322 (ISSN) ; Ahansaz, B ; Maleki, A ; Sharif University of Technology
Nature Research
2023
Abstract
Quantum metrology employs nonclassical systems to improve the sensitivity of measurements. The ultimate limit of this sensitivity is dictated by the quantum Cramér–Rao bound. On the other hand, the quantum speed limit bounds the speed of dynamics of any quantum process. We show that the speed limit of quantum dynamics sets a fundamental bound on the minimum attainable phase estimation error through the quantum Cramér–Rao bound, relating the precision directly to the underlying dynamics of the system. In particular, various metrologically important states are considered, and their dynamical speeds are analyzed. We find that the bound could, in fact, be related to the nonclassicality of...
Discrete multitone modulation with biorthogonal filter bank
, Article 3rd IEEE International Symposium on Signal Processing and Information Technology, ISSPIT 2003, 14 December 2003 through 17 December 2003 ; 2003 , Pages 34-37 ; 0780382927 (ISBN); 9780780382923 (ISBN) ; Shamsollahi, M. B ; Abdi, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2003
Abstract
Discrete multitone (DMT) modulation is used for the efficient transmission of data over nonideal channels. By nonideal channel, we mean that the channel with the frequency response is not flat. Also the noise is present in this kind of channel. In recent years, optimization of filter banks for the DMT systems is considered. Recent researches focused on the orthonormal filter banks have shown that the principal component filter bank (PCFB) is optimal for this application. We focus on one class of biorthogonal filter banks and find the optimum solution for this class. We also have shown that the performance of this structure is better than the optimum orthonormal filter bank. © 2003 IEEE
Size-controlled synthesis of superparamagnetic iron oxide nanoparticles and their surface coating by gold for biomedical applications
, Article Journal of Magnetism and Magnetic Materials ; Volume 324, Issue 23 , November , 2012 , Pages 3997-4005 ; 03048853 (ISSN) ; Simchi, A ; Imani, M ; Costa, B. F. O ; Sharif University of Technology
2012
Abstract
The size mono-dispersity, saturation magnetization, and surface chemistry of magnetic nanoparticles (NPs) are recognized as critical factors for efficient biomedical applications. Here, we performed modified water-in-oil inverse nano-emulsion procedure for preparation of stable colloidal superparamagnetic iron oxide NPs (SPIONs) with high saturation magnetization. To achieve mono-dispersed SPIONs, optimization process was probed on several important factors including molar ratio of iron salts [Fe 3 and Fe 2], the concentration of ammonium hydroxide as reducing agent, and molar ratio of water to surfactant. The biocompatibility of the obtained NPs, at various concentrations, was evaluated via...
Residual stress analysis of autofrettaged thick-walled spherical pressure vessel
, Article International Journal of Pressure Vessels and Piping ; Volume 87, Issue 7 , July , 2010 , Pages 396-401 ; 03080161 (ISSN) ; Farrahi, G. H ; Haghpanah Jahromi, B ; Hosseinian, E ; Sharif University of Technology
2010
Abstract
In this study, residual stress distributions in autofrettaged homogenous spherical pressure vessels subjected to different autofrettage pressures are evaluated. Results are obtained by developing an extension of variable material properties (VMP) method. The modification makes VMP method applicable for analyses of spherical vessels based on actual material behavior both in loading and unloading and considering variable Bauschinger effect. The residual stresses determined by employing finite element method are compared with VMP results and it is demonstrated that the using of simplified material models can cause significant error in estimation of hoop residual stress, especially near the...
A novel enzyme based biosensor for catechol detection in water samples using artificial neural network
, Article Biochemical Engineering Journal ; Volume 128 , 2017 , Pages 1-11 ; 1369703X (ISSN) ; Kashanian, S ; Maleki, E ; Nazari, M ; Sharif University of Technology
Elsevier B.V
2017
Abstract
Biosensors could be used as digital devices to measure the sample infield. Consequently, computational programming along with experimental achievements are required. In this study, a novel biosensor/artificial neural network (ANN) integrated system was developed. Poly (3,4-ethylenedioxy-thiophene)(PEDOT), graphene oxide nano-sheets (GONs) and laccase (Lac) were used to construct a biosensor. The simple and one-pot process was accomplished by electropolymerizing 3,4-ethylenedioxy-thiophene (EDOT) along with GONs and Lac as dopants on glassy carbon electrode. Scanning electron microscopy (SEM) and electrochemical characterization were conducted to confirm successful enzyme entrapment. The...
Fractal flow of inhomogeneous fluids over smooth inclined surfaces and determination of their fractal dimensions and universality classes
, Article Journal of Physics Condensed Matter ; Volume 17, Issue 14 , 2005 , Pages S1219-S1227 ; 09538984 (ISSN) ; Ghane Motlagh, B ; Baradaran, S ; Shekarian, E ; Rouhani, S ; Sharif University of Technology
2005
Abstract
Patterns formed by the flow of an inhomogeneous fluid (suspension) over a smooth inclined surface were studied. It was observed that fractal patterns are formed. There exists a threshold angle for the inclination above which global fractal patterns are formed. This angle depends on the particle size of the suspension. We observed that there are two fractal dimensions for these patterns, depending on the area from which the pattern is extracted. If the pattern is taken from the top which only consists of the beginning steps of the pattern forming, one finds two fractal dimensions, i.e. 1.35-1.45 and 1.6-1.7, in which the first one is dominant. And if the entire pattern is taken, then fractal...
Fractal behaviour of flow of inhomogeneous fluids over smooth inclined surfaces
, Article Journal of Physics Condensed Matter ; Volume 16, Issue 15 , 2004 , Pages 2497-2505 ; 09538984 (ISSN) ; Ghane Motlagh, B ; Baradaran, S ; Shekarian, E ; Rouhani, S ; Sharif University of Technology
2004
Abstract
Patterns formed by the flow of an inhomogeneous fluid (suspension) over a smooth inclined surface were studied. It was observed that fractal patterns form. There exists a threshold angle for the inclination above which global fractal patterns are formed. This angle depends on the particle size of the suspension. We observed that there are two fractal dimensions for these patterns, depending on the area from which the pattern is extracted. If the pattern is taken from the top which only consists of the beginning steps of the pattern forming, one finds two fractal dimensions, i.e. 1.35-1.45 and 1.6-1.7, in which the first one is dominant while, if the entire pattern is taken, then a fractal...
Effects of constrained groove pressing, severe shot peening and ultrasonic nanocrystal surface modification on microstructure and mechanical behavior of S500MC high strength low alloy automotive steel
, Article Applied Surface Science ; Volume 538 , 2021 ; 01694332 (ISSN) ; Celik, M. B ; Husem, F ; Maleki, E ; Amanov, A ; Unal, O ; Sharif University of Technology
Elsevier B.V
2021
Abstract
S500MC high strength low alloy automotive steel is exposed to bulk severe plastic deformation (SPD) via constrained groove pressing (CGP) and surface severe plastic deformation (S2PD) via severe shot peening (SSP) and ultrasonic nanocrystal surface modification (UNSM). SSP and UNSM could create a nanocrystallization layer till 50–100 µm away from outmost surface. EBSD investigations showed average nano-grain size obtained via SSP and UNSM was found to be below 100 nm regime. The strength was improved via 1st to 4th pass of CGP, but elongation percentage decreased abruptly. UNSM achieves both strength-ductility improvement with gradient structure. SSP improves the total elongation however a...
Policy Instruments for the Improvement of Customers’ Willingness to Purchase Electric Vehicles: A Case Study in Iran
, Article Energies ; Volume 15, Issue 12 , 2022 ; 19961073 (ISSN) ; Mirzamohammadi, S ; Naeini, A. B ; Maleki, A ; Mobayen, S ; Skruch, P ; Sharif University of Technology
MDPI
2022
Abstract
Given the various advantages of electric vehicles compared to conventional gasoline vehicles in terms of energy efficiency and environmental pollution (among others), this paper studies the factors affecting customers’ willingness to purchase electric vehicles. An integrated discrete choice and agent-based approach is applied to model the customers’ choice for the valuation of electric vehicles based on the internal reference price. The agent-based model evaluates customers’ preferences for a number of personal and vehicle attributes, according to which vehicle they chose. Data from 376 respondents are collected to estimate a random-parameter logit model where customers are asked to reveal...
Modeling of severe shot peening effects to obtain nanocrystalline surface on cast iron using artificial neural network
, Article Materials Today: Proceedings ; Volume 3, Issue 6 , 2016 , Pages 2197-2206 ; 22147853 (ISSN) ; Sharif University of Technology
Elsevier Ltd
2016
Abstract
Severe plastic deformation methods such as severe shot peening are used in order to improve mechanical properties of the components by surface microstructure nanocrystallization. Severe shot peening is one of the popular mechanical surface treatments generally aimed at generating nanograined layer and compressive residual stress close to the surface. Moreover, artificial neural network has been used as an efficient approach to predict and optimize the engineering problems. In present study effects of conventional and severe shot peening on cast iron were modelled by means of artificial neural networks and they were compared. The obtained results indicate that severe shot peening has superior...
Synthesis and analysis of the properties of ferro-fluids
, Article ICONN 2010 - Proceedings of the 2010 International Conference on Nanoscience and Nanotechnology, 22 February 2010 through 26 February 2010, Sydney, NSW ; 2010 , Pages 91-93 ; 9781424452620 (ISBN) ; Ghane Motlagh, B ; Ghane Golmohamadi, F ; Ghane Motlagh, R ; Rouhani, S ; Sharif University of Technology
2010
Abstract
We report the rheological properties of ferro-fluid (FF) containing iron oxide nano-particles. At first, a FF was synthesized by using chemical co-precipitaton[1]. The microstructure study using SEM revealed that the FF contained nano-particles with the mean particle size of 35nm. The XRD study revealed that we have well crystallized structures of magnetite; they appeared to be approximately single crystalline structures. The rheological results proved that the FF has non Newtonian behavior, it is a shear thinning fluid in all magnetic fields, Moreover, the magnetic field increases the viscosity in a definite shear rate due to the nano-particles agglomerations and formation of chain-like...
Power-aware performance analysis of self-adaptive resource management in IaaS clouds
, Article Future Generation Computer Systems ; Volume 86 , 2018 , Pages 134-144 ; 0167739X (ISSN) ; Entezari Maleki, R ; Etesami, S. E ; Egger, B ; Ardagna, D ; Movaghar, A ; Sharif University of Technology
Elsevier B.V
2018
Abstract
In this paper, Stochastic Activity Networks (SANs) are used to model and evaluate the performance and power consumption of an Infrastructure-as-a-Service (IaaS) cloud. The proposed SAN model is scalable and flexible, yet encompasses some details of an IaaS cloud, such as Virtual Machine (VM) provisioning, VM multiplexing, and failure/repair behavior of VMs. Using the proposed SAN, a power-aware self-adaptive resource management scheme is presented for IaaS clouds that automatically adjusts the number of powered-on Physical Machines (PMs) regarding variable workloads in different time intervals. The proposed scheme respects user-oriented metrics by avoiding Service Level Agreement (SLA)...
Modeling and evaluation of dispatching policies in IaaS cloud data centers using SANs
, Article Sustainable Computing: Informatics and Systems ; Volume 33 , 2022 ; 22105379 (ISSN) ; Entezari Maleki, R ; Etesami, S. E ; Egger, B ; Sousa, L ; Movaghar, A ; Sharif University of Technology
Elsevier Inc
2022
Abstract
Infrastructure-as-a-Service (IaaS) clouds not only have to meet business requirements but also need to consider other important metrics that influence the quality of service, such as performance, availability, and power consumption. In this paper, we present a Stochastic Activity Network (SAN) based analytical approach that simultaneously computes these metrics under a given load for IaaS cloud data centers. The model's high-level abstraction of IaaS clouds allows us to evaluate different resource management strategies and features, including cloud federation and dispatching policies. In a first step, we model a single rack including its autonomous local manager responsible for scheduling...
Cost-Aware resource recommendation for Dag-based big data workflows: an apache spark case study
, Article IEEE Transactions on Services Computing ; Volume 16, Issue 3 , 2023 , Pages 1726-1737 ; 19391374 (ISSN) ; Karimian Aliabadi, S ; Entezari Maleki, R ; Egger, B ; Movaghar, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2023
Abstract
The era of personal resources being sufficient for enterprise big data computations has passed. As computations are executed in the cloud, small policy changes of cloud operators may cause considerable changes in operational costs. Carefully choosing the amount of resources for a given application is thus of great importance. This, however, requires a priori knowledge of the application's performance under different configurations. Creating a performance prediction model needs to account for the heterogeneity of resources and the diversity in application workflows. Previous approaches for heterogeneous environments consider a black-box representation of the application which results in...
Evaluation of Response Modification Factor for Cable Styaed Bridges
, M.Sc. Thesis Sharif University of Technology ; Maleki, Shervin (Supervisor)
Abstract
Bridges are among the crucial elements of transportation networks and play an important role in facilitating emergency relief efforts following earthquakes. For this reasons, they should have an appropriate performance in earthquakes; Thus, presentation of true design of bridges was necessary. Elastic design of bridges due to the earthquake is uneconomic; hence, during an earthquake, the codes permitted to structures go to their inelastic behavior domain but inelastic analysis of structures are noncommercial and the capability of detail modeling of the inelastic behavior of the material is still impossible. Therefore, designers use response modification factor to consider the inelastic...
Fixed-point iteration approach to spark scalable performance modeling and evaluation
, Article IEEE Transactions on Cloud Computing ; 2021 ; 21687161 (ISSN) ; Aseman Manzar, M ; Entezari Maleki, R ; Ardagna, D ; Egger, B ; Movaghar, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2021
Abstract
Companies depend on mining data to grow their business more than ever. To achieve optimal performance of Big Data analytics workloads, a careful configuration of the cluster and the employed software framework is required. The lack of flexible and accurate performance models, however, render this a challenging task. This paper fills this gap by presenting accurate performance prediction models based on Stochastic Activity Networks (SANs). In contrast to existing work, the presented models consider multiple work queues, a critical feature to achieve high accuracy in realistic usage scenarios. We first introduce a monolithic analytical model for a multi-queue YARN cluster running DAG-based Big...
Fixed-Point Iteration Approach to Spark Scalable Performance Modeling and Evaluation
, Article IEEE Transactions on Cloud Computing ; Volume 11, Issue 1 , 2023 , Pages 897-910 ; 21687161 (ISSN) ; Aseman Manzar, M. M ; Entezari Maleki, R ; Ardagna, D ; Egger, B ; Movaghar, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2023
Abstract
Companies depend on mining data to grow their business more than ever. To achieve optimal performance of Big Data analytics workloads, a careful configuration of the cluster and the employed software framework is required. The lack of flexible and accurate performance models, however, render this a challenging task. This article fills this gap by presenting accurate performance prediction models based on Stochastic Activity Networks (SANs). In contrast to existing work, the presented models consider multiple work queues, a critical feature to achieve high accuracy in realistic usage scenarios. We first introduce a monolithic analytical model for a multi-queue YARN cluster running DAG-based...