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shoushtari--shirin
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Investigation of segregation of large particles in a pressurized fluidized bed with a high velocity gas: A discrete particle simulation
, Article Powder Technology ; Volume 246 , September , 2013 , Pages 398-412 ; 00325910 (ISSN) ; Hosseini, S. A ; Soleimani, R ; Sharif University of Technology
2013
Abstract
A numerical study on mixing/segregation phenomena in a pressurized fluidized bed with large particles of Geldart D type of binary density but same diameter with high velocity gas was performed by the use of discrete particle simulation. Particle mixtures are composed of spherical particles with 2mm diameter and 1g/cm3 flotsam density and different jetsam densities of 1.25, 2 and 2.5g/cm3 with jetsam volume fraction of 0.5. The particles are initially packed approaching perfect mixing state in a rectangular bed and then fluidized by gas uniformly injected at the bottom of the bed. Effect of increase of pressure and density ratio was investigated and mixing/segregation behavior is discussed in...
Designing EEG-based Deep Neural Network for Analysis of Functional and Effective Brain Connectivity
, M.Sc. Thesis Sharif University of Technology ; Mohammadzadeh, Hoda (Supervisor) ; Amini, Arash (Supervisor)
Abstract
Brain states analysis during consciousness is emerging research in brain-computer interface(BCI). Emotion recognition can be applied to learn brain states and stages of neural activities. Therefore, emotion recognition is crucial to the analysis of brain functioning. Electrical signals such as electroencephalogram (EEG), electrocardiogram (ECG) and functional magnetic resonance imaging(fMRI) are frequently used in emotion recognition researches. Convenience in recording, non-invasive nature and high temporal resolution are the factors that have made EEG popular in brain researches. EEG can be used to identify brain region activity solely or the connectivity of various regions in time in the...
Supply Chain Risk Study for Downstream Projects of Oil and Gas Industry in Iran
, M.Sc. Thesis Sharif University of Technology ; Aslani, Shirin (Supervisor)
Abstract
There are always some unpredictable phenomena happen in the process of constructing of a downstream petrochemichal plant resulting to delays that increase the cost compared with the benefits or sometimes cancelation of the projects that abodones the investors from the returns at all. On of the reasons that these issues can dwibdles the benefits is that most of Iranian’s downstream companies do not prepare suitable and sufficient capabilitities to cope with such a risks. In this thesis, at first, influensive risks on the downstream oil and gas projects in Iran have been studied based on a comprehensive litreture review, secondly using a questionnaire, these extracted risks have been assessed...
A Study on Strategic Behavior of Drivers on Ride-hailing Platforms
, M.Sc. Thesis Sharif University of Technology ; Aslani, Shirin (Supervisor)
Abstract
Recently, the advent of online platforms as an intermediary tool has provided an opportunity for service providers and manufacturers to offer their services/products to consumers. Ride-hailing platforms are an example of these businesses where independent drivers and passengers are matched via an online platform. One of the most significant challenges faced by these companies is the emergence of strategic behaviors on both the demand and the supply side, which might affect the performance and profitability of the platform.In this thesis, we study the strategic behavior of drivers and its impact on their performance, using the data of one of the largest ride-hailing companies in Iran. We use...
Tracking Consumers Throughout Their Purchase Journey: Using Deep Learning Methods
, M.Sc. Thesis Sharif University of Technology ; Aslani, Shirin (Supervisor)
Abstract
Over the past two decades, the interest in exploring consumers' behavior has risen to popularity. Nowadays, it is necessary for marketers to reach out to the right consumers at the right time and with the right message. Even though the positive impact of tracking consumers throughout their purchase journey and its managerial implications have been emphasized several times by academics, There is still a lack of practical research on how to discern the consumers' stage in the purchase journey from a holistic point of view. In this study, we develop several machine learning models, including RNNs (GRU and LSTM), Transformers, and XGBoost, by utilizing historical data of Yektanet (the leading...
Mining the Tenant Experience: Uncovering the Determinants of Residential Satisfaction through Topic Modelling of Online Rental Apartment Reviews
, M.Sc. Thesis Sharif University of Technology ; Aslani, Shirin (Supervisor)
Abstract
Residential satisfaction plays a pivotal role in shaping liveable cities, profoundly influencing individuals' health and well-being. In contrast, dissatisfaction in living environments often triggers relocation intentions, leading to significant vacancy costs for landlords and property managers. While previous studies predominantly relied on traditional methods like surveys and interviews, our research adopts a novel, bottom-up approach, analysing this phenomenon through the lens of residents themselves. Leveraging a custom-developed Python-based web scraper, we meticulously gathered 195,000 online reviews from apartments.com. This comprehensive dataset spans the most populous cities and...
Characterization of liquid bridge formed during gas-oil gravity drainage in fractured porous media
, Article 16th European Conference on the Mathematics of Oil Recovery, ECMOR 2018, 3 September 2018 through 6 September 2018 ; 2018 ; 9789462822603 (ISBN) ; Masihi, M ; Ghazanfari, M. H ; Shoushtari, A ; Sharif University of Technology
European Association of Geoscientists and Engineers, EAGE
2018
Abstract
Gas-oil gravity drainage that takes place in the gas-invaded zone of fractured reservoirs is the main production mechanism of gas-cap drive fractured reservoirs as well as fractured reservoirs subjected to gas injection. Interaction of neighboring matrix blocks through reinfiltration and capillary continuity effects controls the efficiency of gravity drainage. Existence of capillary continuity between adjacent matrix block is likely to increase the ultimate recovery significantly. Liquid bridge formed in fractures has a significant role in maintaining the capillary continuity between two neighboring matrix blocks. The degree of capillary continuity is proportional to capillary pressure in...
Some improvements on the unfolding inverse finite element method for simulation of deep drawing process
, Article International Journal of Advanced Manufacturing Technology ; Vol. 72, issue. 1-4 , 2014 , pp. 447-456 ; ISSN: 02683768 ; Assempour, A ; Sharif University of Technology
2014
Abstract
The linear unfolding inverse finite element method (IFEM) has been modified and enhanced by implementing large deformation relations. The method is helpful to predict forming severity of the part that should be deep drawn as well as its blank shape and strain distribution in preliminary design stage. The approach deals with minimization of potential energy and large deformation relations with membrane elements. To reduce the computation time, the part is unfolded properly on the flat sheet and treated as 2D problem. Moreover, the nonlinear stress-strain relationship of plastic material properties has been considered to increase the accuracy of the results. An experiment set up has been...
A new mapping technique to consider intermediate stages in multistep deep drawing
, Article Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science ; Volume 228, Issue 9 , June , 2014 , Pages 1557-1569 ; ISSN: 09544062 ; Assempour, A ; Sharif University of Technology
2014
Abstract
The inverse solution is helpful to determine the drawability of a part and drawing parameters at the initial design stage. The usual inverse algorithms consider the drawing process that occurs in one step and therefore they are not able to analyze the processes which need more than one drawing step. Therefore, multistep inverse solution has been used for such problems. The multistep inverse solution deals with finding the initial guesses of nodal positions on intermediate stages and solving inverse equations between two consecutive steps. In this paper, a new mapping method has been developed to find the initial nodal positions on intermediate stages and the unfolding technique has been...
Examining Customer Behavior In Regarding OBA
, M.Sc. Thesis Sharif University of Technology ; Aslani, Shirin (Supervisor)
Abstract
In recent years, Internet advertising has become increasingly customized to individual users. As advertising carry on refining its capacities, it is more likely to be seen as insightful and useful by everyone. Consumers, particularly Gen Y and older members of Gen Z, are becoming more accepting of relevant advertising as digital acquaintance. Consumers now welcome active advertising that responds and reflects social activity, location, and brand and product preferences in real-time. This ability to be agile within the consumer’s connected experience is an emerging revenue driver and will continue to grow as ad platforms and ad presentations become smarter. But more personalization results in...
Investigation on the Effect of Product Involvement in Online Targeted Advertising
, M.Sc. Thesis Sharif University of Technology ; Aslani, Shirin (Supervisor)
Abstract
Nowadays, one of the most popular methods of advertising is online advertising, which is commonly used by many businesses. In the meantime, targeting the right person at the right moment to show an advertisement is always a major concern of advertisers and other players in this field. One of the areas of study in the literature in this field is the investigation of factors affecting the effectiveness of targeted advertising. The purpose of the upcoming research is to investigate the impact of the advertised product involvement in targeted online advertising. This level of effectiveness is measured by considering click intention as a measure of effectiveness and examining the impact of...
Studies on Modeling of Bioreactors for Removal of Pollutants in Flue Gas
, M.Sc. Thesis Sharif University of Technology ; Vosoughi, Manoochehr (Supervisor) ; Yaghmaei, Soheila (Supervisor)
Abstract
In present study, two bioreactors for biological and chemical removal of nitrogen oxides are modeled. Nitrogen oxides are of the most important pollutants in flue gas stream. These components are hazardous materials and could lead to acid rain, ground-level ozone, smog and the depletion of ozone layer. There are several methods for removing these pollutants which are categorized to two main groups: non-biological and biological methods. Biological removal has the advantage of removing the pollutants by an acceptable efficiency. In present study, two packed-bed bioreactors are modeled by the means of considering two kinds of biological removal mechanism in defined operating conditions. The...
Fundamental Factors Influencing Selection and Continuous use of Online Learning Solutions and Identifiying their Values by Conjoint Analysis Method
, M.Sc. Thesis Sharif University of Technology ; Aslani, Shirin (Supervisor)
Abstract
With the easy access to internet and connected devices ubiquities, Today more than 50 million people use online education platforms to improve their skills and broaden their knowledge. In this research we tend to answer two questions based on data from Iranian students from top domestic universities.First question is which factors would these users consider in choosing their online education platform. This would be especially interesting to know in context of Iran’s cultural and job market situations.Second question we are interested in the same context is what are the factors that make users of these platforms to stop using them. This is very important since stoppage rate of online...
Study Ride Sourcing Driver’s Behavior in Rejecting or Accepting Ride Requests
, M.Sc. Thesis Sharif University of Technology ; Aslani, Shirin (Supervisor)
Abstract
From the beginning of current decade, ride souring in two sided platforms started its activities in Iran and after few years could reach to 10 billion Tomans turnover per year. Now a day Ride sourcing has more than 30 million users in Iran. These days there are more than 5 million price checks in ride sourcing mobile applications from passenger side but, only in half of them passengers and drivers get match. In this situation, one of the biggest challenges of ride sourcing companies is driver’s acceptance rate. Improving acceptance rate could make market bigger, increase utilization and driver satisfaction rate. According to explained need, this study with cooperating of the ride sourcing...
Investigating the Factors Affecting the Migration of Iranian University Students Using the Clustering Method
, M.Sc. Thesis Sharif University of Technology ; Aslani, Shirin (Supervisor)
Abstract
Nowadays, the brain drain problem has become a challenge for countries of origin (COO) and a blessing for countries hosting student migrants. This issue has been studied in many domestic and international types of research. These studies' results can lead to the ability to identify the causes and discover methods to solve this problem. For several decades, the human capital flight has been one of the most challenging educational-economic-social problems in Iran and has grown significantly in recent years. The waste of the country's resources, the ineffectiveness of the education provided to students to improve the country's condition and its construction, the social and psychological...
Examining the Emotions in Twitter Social Media Users' Comments Regarding the Viral Tweets of Luxury Brands Compared to Non-Luxury Brands
, M.Sc. Thesis Sharif University of Technology ; Aslani, Shirin (Supervisor)
Abstract
In this research, we will examine the emotions in the comments recorded about the tweets that have gone viral on the Twitter social media. We use Ekman's emotion classification model to classify emotions. Also, we choose the desired brands from the international brands of the fashion and clothing industry. These brands are divided into 2 luxury and non-luxury categories. Finally, we select 10 luxury brands and 9 non-luxury brands and extract all their tweets in a period of 6 months. Tweets that have been published more than a certain amount are considered as viral tweets, and using a machine learning model designed for this purpose, the emotions in the comments of users are analyzed and...
Predicting the Polarity of Electronic Word-of-Mouth Communication Created on Tweets Messages Posted by Health Policy Makers Related to Covid-19
, M.Sc. Thesis Sharif University of Technology ; Aslani, Shirin (Supervisor)
Abstract
Health influencers leveraged social networks to connect with people and society during the Covid-19 crisis. Platforms like Twitter served as suitable channels for disseminating published messages through word-of-mouth communication. In times of crises like Covid-19, individuals and organizations involved in managing the situation harnessed this capability, contingent upon the quantity and quality of word-of-mouth exchanges. During public crises, public polarity and sentiment toward the issue and the maintenance of public morale hold paramount significance. Consequently, crafting messages that garner positive word-of-mouth communication became a focal point for health influencers. In this...
Analysis of accumulators configuration in LB-LOCA for Bushehr NPP
, Article Annals of Nuclear Energy ; Volume 92 , 2016 , Pages 96-106 ; 03064549 (ISSN) ; Jafari, J ; Aghaie, M ; Vosoughi, N ; Nemati, M ; Sharif University of Technology
Elsevier Ltd
2016
Abstract
This research focuses on a sensitivity analysis of accumulators configuration in a Large Break Loss of Coolant Accident (LB-LOCA) in Bushehr Nuclear Power Plant (BNPP). In this way, primary and secondary side components are modeled using RELAP5/MOD3.3 code. Having modeled the BNPP in a steady state hot full power operation, the thermal hydraulic consequences of a LB-LOCA in the reactor inlet is considered and sensitivity analysis for four major different configurations of accumulators are studied in detail. It is shown that any arrangement of accumulators in the Reactor Pressure Chamber (RPC) or Reactor Collection Chambers (RCC) leads to variation of fuel and clad temperatures during the...
Analysis of deep drawing process to predict the forming severity considering inverse finite element and extended strain-based forming limit diagram
, Article Journal of Computational and Applied Research in Mechanical Engineering ; Volume 8, Issue 1 , 2018 , Pages 39-48 ; 22287922 (ISSN) ; Hashemi, R ; Assempour, A ; Sharif University of Technology
Shahid Rajaee Teacher Tarining University (SRTTU)
2018
Abstract
An enhanced unfolding inverse finite element method (IFEM) is used together with an extended strain-based forming limit diagram (EFLD) to develop a fast and reliable approach to predict the feasibility of the deep drawing process of a part and determining where the failure or defects can occur. In the developed unfolding IFEM, the meshed part is properly fold out on the flat sheet and treated as a 2D problem to reduce the computation time. The large deformation relations, nonlinear material behavior and friction conditions in the blank holder zone are also considered to improve the accuracy and capability of the proposed IFEM. The extended strain-based forming limit diagram based on the...
Characteristics of Different Clusters of Studends who Migrated in 1370s
, M.Sc. Thesis Sharif University of Technology ; Aslani, Shirin (Supervisor)
Abstract
Every year, a high percentage of university graduates go abroad to continue their studies. Large amount of them, especially those who graduated from better universities, do not return to Iran. the emigration of these people, who are considered to be of the best graduates in the country, and their non-return to the country leads to Decrease in the average capability of the country's human resources, waste of resources spent on them from a national perspective, Decrease in the productivity at the internal universities, industries and services and increase in the country's scientific distance from the other countries. the 1370s are an important section in the country's history due to post-war...