A Promotion Optimization Model in Retail Markets using Machine Learning Approach

, M.Sc. Thesis Sharif University of Technology Asadi, Ali (Author) ; Sedghi, Nafiseh (Supervisor)

Abstract

Determining a promotion planning is a critical decision for retail managers. This plan should decide on the amount and duration of promotions for each product in a way that maximizes profit compared to a non-promotion scenario. In this study, the promotion optimization problem in a retail environment is formulated as a non-linear integer programming problem. The objective function is to maximize profit from product sales during the sales period. The problem also includes several business-related constraints that limit the number of promotions. In this study, a reinforcement learning approach, specifically Deep Q-Network, has been used to solve the mathematical model. The implementation...

Two-Period Pricing and Sales Channels Selection with Fairness Concern

, M.Sc. Thesis Sharif University of Technology Jaberi, Sara (Author) ; Sedghi, Nafiseh (Supervisor)

Abstract

Pricing and revenue management are among the most important decisions for any economic enterprise. Several factors can influence decisions in this area and change the company’s pricing strategy, including uncertainties in product demand and customer preferences. This factor becomes particularly significant when the product is newly launched. Therefore, over time, customer preferences and willingness to pay may increase through various advertisements such as customer reviews and word-of-mouth. With rising demand, the seller has the opportunity to raise prices in the next periods. However, price increases can lead to unfair pricing perceptions by customers, hence reducing their purchasing...

Multi-tariff Pricing of Internet Plans Considering Customer Choice Models

, M.Sc. Thesis Sharif University of Technology Zeidvand, Nafiseh (Author) ; Sedghi, Nafiseh (Supervisor)

Abstract

One of the important factors that are effective in the continuation of businesses is their profitability. Pricing, as an important component of the business process, greatly impacts profitability. Therefore, by using a suitable pricing method, retailers and service providers can increase their profits and avoid issues such as inventory congestion, imposed discounts, or lost sales opportunities. In this research, the two-tariff pricing system in internet services is investigated and determined by taking into account the randomness of customer consumption. The problem includes a set of Internet sales plans, each plan has a fixed price for a certain amount of data and a variable price for...

Hydrogen desorption properties of MgH 2–TiCr 1.2 Fe 0.6 nanocomposite prepared by high-energy mechanical alloying [electronic resource]

, Article Journal of Power Sources ; 2011, Vol. 196, No.10, P.4604-4608 Mahmoudi, N. (Nafiseh) ; Kaflou, A ; Simchi, A. (Abdolreza) ; Sharif University of Technology

Abstract

In the present work, high-energy mechanical alloying (MA) was employed to synthesize a nanostructured magnesium-based composite for hydrogen storage. The preparation of the composite material with composition of MgH2–5at% (TiCr1.2Fe0.6) was performed by co-milling of commercial available MgH2 powder with the body-centered cubic (bcc) alloy either in the form of Ti–Cr–Fe powder mixture with the proper mass fraction (sample A) or prealloyed TiCr1.2Fe0.6 powder (sample B). The prealloyed powder with an average crystallite size of 14nm and particle size of 384nm was prepared by the mechanical alloying process. It is shown that the addition of the Ti-based bcc alloy to magnesium hydride yields a...

Pricing of Infrastructure as a Service in Cloud Computing

, M.Sc. Thesis Sharif University of Technology Shahmoradi, Mohammad Hossein (Author) ; Sedghi, Nafiseh (Supervisor)

Abstract

The growing demand for scalable and cost-effective computing resources has led to the widespread adoption of the Infrastructure as a Service (IaaS) model in cloud computing. One of the pricing models for resources, or virtual machines, in this service is the Spot model, which allows customers to access unused cloud server capacity at significantly lower costs compared to other models. However, despite their affordability, these virtual machines do not come with a Service Level Agreement (SLA) and may experience interruptions during use. Such interruptions increase the time required for customers to complete their tasks. In this study, we utilize discrete-event system simulations to examine...

Data-Driven Pricing Based on Demand Prediction Using Machine Learning Methods

, M.Sc. Thesis Sharif University of Technology Khosroshahi, Fatemeh Zahra (Author) ; Sedghi, Nafiseh (Supervisor)

Abstract

Pricing plays an important and essential role in the profit and income of companies. The importance of pricing is not only related to its role in the company's profitability, but it also changes the customer's understanding and loyalty towards the company and can create the company's reputation or destroy it. Determining the right price will increase product sales and increase customer loyalty and create a competitive advantage for the company. One of the most important and influential variables in product pricing is the amount of demand. The main challenge of companies for product pricing is the uncertainty in their demand. In order to deal with this problem, data-driven pricing is used....

Using Machine Learning Approaches for Persian Pronoun Resolution

, M.Sc. Thesis Sharif University of Technology Moosavi, Nafiseh Sadat (Author) ; Ghasem Sani, Gholamreza (Supervisor)

Abstract

Coreference resolution is an essential step toward understanding discourses, and it is needed by many NLP tasks such as summarization, machine translation, question answering, etc. Pronoun resolution is a major and challenging subpart of coreference resolution, in which only the resolution of pronouns is considered. The existing coreference resolution approaches can be classified into two broad categories: linguistic and machine learning approaches. Linguistic approaches need a lot of linguistic information for the resolution process. Acquisition of such information is an error- prone and time-consuming process. In contrast, learning approaches need less linguistic information and provide...

Link Prediction using Dynamic Graph Neural Network with Application to Call Data

, M.Sc. Thesis Sharif University of Technology Sajadi, Nafiseh Sadat (Author) ; Jafari Siavoshani, Mahdi (Supervisor)

Abstract

In network science, link prediction is one of the essential tasks that has been neglected. One important application of link prediction in telecommunication networks is analyzing the user's consumption pattern to provide better service. This project aims to predict future links with applications to call data using the users' call history. In previous research, there are two main approaches: 1) heuristic-based approach, and 2) deep-learning-based approach, such as graph neural networks. These methods are mainly used for processing static graphs, and therefore, we cannot generalize them to dynamic graphs. But there are many graphs which are dynamic in nature. For instance, call data records...

Synthesis, Characterization and Application of Porous Bioactive Glasses-Based Nanostructures in Bone Tissue Engineering

, Ph.D. Dissertation Sharif University of Technology Aldhaher, Abdullah (Author) ; Bagherzadeh, Mojtaba (Supervisor) ; Baheiraei, Nafiseh (Co-Supervisor)

Abstract

In the upcoming research, with the aim of bone tissue engineering and achieving a new structure, a scaffold based on polyhema (PHEMA) and gelatin (Gel), which are biocompatible polymers for bone tissue, was made and evaluated. Also, in order to improve the bioactivity and mechanical properties, bioactive glass alone (BG45S5) or together with strontium (BG-Sr) was used in the scaffold structure. and chemical by conducting FTIR, XRD, SEM, mechanical strength, bioactivity measurement, contact angle, water absorption and degradation tests. Biological investigations were done using mesenchymal stem cells derived from human bone marrow and with the help of MTT evaluations and SEM photography. The...

Simulation of wetting tendency of fluids with high density ratios using RK Lattice Boltzmann method

, Article 16th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering, ARC 2019, 14 October 2019 through 18 October 2019 ; 2020 Sadeghi, M ; Pak, A ; Sadeghi, H ; Sharif University of Technology

Asian Regional Conference on Soil Mechanics and Geotechnical Engineering 2020

Abstract

Several lattice Boltzmann models for multi-phase flow have been developed, but few of them are capable of modeling fluid flows with high density ratio in the order of 1000. Therefore, an advanced chromodynamics, Rothmann-Keller (RK) type model is employed in current study, which can handle liquid-gas density ratio in the order of 1000 and viscosity ratio in the order of 100. Other distinctive characteristics of the proposed model are high stability, and capability of setting parameters such as surface tension independently. In spite of these benefits, the original RK model fails to model wetting tendency of the fluids. As a result, it is impossible to correctly simulate two-fluid phase flow...

A Thesis Submitted in Partial Fulfilment of the Requirements for the Degree of Master of Arts in Teaching English as a Foreign Language

, M.Sc. Thesis Sharif University of Technology Haeri, Nafiseh Sadat (Author) ; Alemi, Minoo (Supervisor) ; Meghdari, Ali (Co-Advisor)

Abstract

Although Robot Assisted Language Learning (RALL) has recently received attention as a tool for language learning, its role in pragmatic development has gone unnoticed. Hence, this study sought to explore the effect of RALL on pragmatic learning of greeting, thanking, and request speech acts by young Persian-speaking EFL learners. To this end, 38 preschool female and male kids (3-6 years old) were assigned to the RALL (19 students) and game-based (19 students) groups. The humanoid robot for the RALL group was used as an assistant to the teacher while for the game-based group the instruction was based on gaming methods such as command, mystery bag and pass the ball games. The instructional...

Analytical Nonlinear Solution of a Structurally Integrated Piezoelectric Trapizoidal Tapered Beam for Energy Harvesting

, M.Sc. Thesis Sharif University of Technology Ahsan Esfahani, Nafiseh Sadat (Author) ; Hosseini Kordkheili, Ali (Supervisor)

Abstract

Tapering the beam along its length may lead to an increase in the voltage density of piezoelectric energy harvester. In this study, the energy harvester voltage with linear variable cross section is studied by developing an analytical method in both linear and nonlinear states. In linear mode, the results are compared with the experimental results. For the development of linear and nonlinear analytic relations, the Euler–Bernoulli beam and linear voltage variations in the thickness direction are used, and for the separation of variables, the mass normalized mode shapes has been used. The results of the linear analytical method are compared with the results of past research and experimental...

Mechanical behavior during aging of plastically deformed AA6061-SiCp composite in different temperatures

, Article Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications ; Volume 226, Issue 4 , 2012 , Pages 322-329 ; 14644207 (ISSN) Sadeghi, I ; Serajzadeh, S

SAGE 2012

Abstract

In this study, the kinetics of aging in AA6061 and AA6061 with 5% volume fraction SiCp were studied and compared. The composite was first produced and homogenized using stir casting technique followed by hot extrusion with the ratio of 18:1. Then, both AA6061 and the composite were aged at three different temperatures including room temperature, 170 °C and 240 °C, while mechanical properties during aging were evaluated employing hardness measurements and tensile testing. Moreover, in order to assess the effect of plastic deformation on the kinetics of aging, a series of samples were first deformed by equal-channel angular pressing immediately after solution treatment and then aged in the...

Electroosmotic flow and ionic conductance in a pH-regulated rectangular nanochannel

, Article Physics of Fluids ; Volume 29, Issue 6 , 2017 ; 10706631 (ISSN) Sadeghi, M ; Saidi, M. H ; Sadeghi, A ; Sharif University of Technology

2017

Abstract

Infinite series solutions are obtained for electrical potential, electroosmotic velocity, ionic conductance, and surface physicochemical properties of long pH-regulated rectangular nanochannels of low surface potential utilizing the double finite Fourier transform method. Closed form expressions are also obtained for channels of large height to width ratio for which the depthwise variations vanish. Neglecting the Stern layer impact, the effects of EDL (Electric Double Layer) overlap, multiple ionic species, and association/dissociation reactions on the surface are all taken into account. Moreover, finite-element-based numerical simulations are conducted to account for the end effects as well...

Geotechnical characterization and collapsibility of a natural dispersive loess

, Article Engineering Geology ; Volume 250 , 2019 , Pages 89-100 ; 00137952 (ISSN) Sadeghi, H ; Kiani, M ; Sadeghi, M ; Jafarzadeh, F ; Sharif University of Technology

Elsevier B.V 2019

Abstract

During preliminary investigation phase of the national Chabahar-Zahedan railway line, serious geotechnical problems including non-uniform settlements, tensile cracks, and local collapse were reported in parts of the path near the coastline. A follow-up field investigation revealed that the in-situ soil at construction site has a metastable structure being sensitive to saturation and loading. Therefore, a comprehensive series of physical, chemical, electro-chemical, and geotechnical tests were conducted to classify and characterize the soil properties and behavior in its natural state. The natural soil was classified as a clayey loess with moderately dispersive to dispersive characteristics....

Synthesis, Characterization and Optimization of an In situ Forming Hydrogel Derived from Extracellular Matrix for Cardiac Tissue Engineering Applications

, M.Sc. Thesis Sharif University of Technology Mousavi, Ali (Author) ; Mashayekhan, Shohreh (Supervisor) ; Baheiraei, Nafiseh (Supervisor) ; Pourjavadi, Ali (Co-Supervisor)

Abstract

Myocardial Infarction occurs due to sudden blockage in a coronary artery and causes necrosis of myocardial tissue. Since myocardium is unable to self-regenerate, cardiac tissue engineering has become a promising therapeutic approach for MI treatment by restoring heart function via combination of cells, biomaterials and signaling factors. For this purpose, myocardial extracellular matrix (ECM) is an attractive biomaterial providing better biomimetic for cultured cells. In this project, we synthesized an in situ forming hydrogel derived from myocardial ECM and for improving mechanical and electrical properties of ECM hydrogel we added oxidized alginate (OA) with 5% oxidation degree and APTMS...

Geometry effect on electrokinetic flow and ionic conductance in pH-regulated nanochannels

, Article Physics of Fluids ; Volume 29, Issue 12 , 2017 ; 10706631 (ISSN) Sadeghi, M ; Saidi, M. H ; Moosavi, A ; Sadeghi, A ; Sharif University of Technology

2017

Abstract

Semi-analytical solutions are obtained for the electrical potential, electroosmotic velocity, ionic conductance, and surface physicochemical properties associated with long pH-regulated nanochannels of arbitrary but constant cross-sectional area. The effects of electric double layer overlap, multiple ionic species, and surface association/dissociation reactions are all taken into account, assuming low surface potentials. The method of analysis includes series solutions which the pertinent coefficients are obtained by applying the wall boundary conditions using either of the least-squares or point matching techniques. Although the procedure is general enough to be applied to almost any...

Unsteady solute dispersion by electrokinetic flow in a polyelectrolyte layer-grafted rectangular microchannel with wall absorption

, Article Journal of Fluid Mechanics ; Volume 887 , 2020 Sadeghi, M ; Saidi, M. H ; Moosavi, A ; Sadeghi, A ; Sharif University of Technology

Cambridge University Press 2020

Abstract

The dispersion of a neutral solute band by electrokinetic flow in polyelectrolyte layer (PEL)-grafted rectangular/slit microchannels is theoretically studied. The flow is assumed to be both steady and fully developed and a first-order irreversible reaction is considered at the wall to account for probable surface adsorption of solutes. Considering low electric potentials, analytical solutions are obtained for electric potential, fluid velocity and solute concentration. Special solutions are also obtained for the case without wall adsorption. To track the dispersion properties of the solute band, the generalized dispersion model is adopted by considering the exchange, the convection and the...

Dispersivity, collapsibility and microstructure of a natural dispersive loess from Iran

, Article 16th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering, ARC 2019, 14 October 2019 through 18 October 2019 ; 2020 Sadeghi, H ; Nasiri, H ; Panahi, P. A ; Sadeghi, M ; Sharif University of Technology

Asian Regional Conference on Soil Mechanics and Geotechnical Engineering 2020

Abstract

A new type of collapsible soil was encountered in Southern Iran and caused some serious technical problems including subsidence, collapse and sinkholes during the construction of Zahedan-Chabahar railway. Field observations indicated that in-situ soil contains excessive amount of salts resulting in dispersive features in response to seepage forces in addition to its collapsibility. Therefore, a systematic research plan including field sampling and laboratory testing was carried out to investigate the observed geotechnical features. Results of physio-chemical tests revealed the dominance of Sodium in excess of 70% relative to total dissolved salts, which results in high dispersive potential....

Modified carrageenan. 5. Preparation, swelling behavior, salt- and pH-sensitivity of partially hydrolyzed crosslinked carrageenan-graft-polymethacrylamide superabsorbent hydrogel [electronic resource]

, Article Polymers for Advanced Technologies ; Volume 15, Issue 11, pages 645–653, November 2004 Pourjavadi, A. (Ali) ; Sadeghi, M ; Hosseinzadeh, H

Abstract

The polysaccharide, kappa-carrageenan (κC) was chemically modified to achieve a novel superabsorbent hydrogel via graft copolymerization of methacrylamide (MAM) onto the substrate followed by alkaline hydrolysis. Ammonium persulfate (APS) and N,N′-methylene bisacrylamide (MBA) were used as a free-radical initiator and a crosslinker, respectively. The saponification reaction was carried out using sodium hydroxide aqueous solution. Either κC-g-PMAM or hydrolyzed κC-g-PMAM (PMAM: polymethacrylamide) was characterized by FT-IR spectroscopy. The effect of grafting variables (i.e. concentration of MBA, MAM, and APS) and alkaline hydrolysis conditions (i.e. NaOH concentration, hydrolysis time and...