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    A Process Mining Approach to Analyze Customer Journeys to Improve Customer Experience

    , M.Sc. Thesis Sharif University of Technology Akhavan, Fatemeh (Author) ; Hassannayebi, Erfan (Supervisor)
    Abstract
    With the growth of the number of online service providers and the need to innovate in these services, in this study, the processes and the journeys taken by visitors of a website that provides employment services and employment insurance has been analyzed. In this research, process mining techniques and predictive process monitoring were implemented. With the use of a supervised and unsupervised learning algorithm, it attempted to identify the customer journeys' output and the existing patterns that lead to the complaint. In the first step, the website event log is extracted. Afterward, by using frequency-based encoding methods, the journeys traveled by users were clustered based on the... 

    Predictive Business Process Monitoring Using Machine Learning Algorithms

    , M.Sc. Thesis Sharif University of Technology Feiz, Roya (Author) ; Hassannayebi, Erfan (Supervisor)
    Abstract
    In order to survive in today's business world, which is changing at a very fast pace, organizations can detect deviations even before they occur, quickly and with a high percentage of confidence, by analyzing their processes, in order to prevent disruptions in the processes. by monitoring the information systems that automatically execute business processes, it is possible to ensure the correct implementation of the existing processes. For this purpose, various techniques for monitoring business processes have been presented so that managers have a comprehensive and real view of how implement processes and be able to identify possible deviations in the future and try to fix them because the... 

    Data-Driven Prediction for Monitoring Business Process Pperformances Based on Classification Algorithms

    , M.Sc. Thesis Sharif University of Technology Taheriyan, Zahra (Author) ; Hassannayebi, Erfan (Supervisor)
    Abstract
    In recent years, several studies have been conducted in the field of data mining techniques in the field of process mining with the aim of improving the performance of organizations. Predictive process monitoring is a data-driven approach that helps business managers to improve the status and conditions of their organization. In this approach, the event log, which includes a set of completed examples of a process, is received as input, and machine learning methods are used to predict the outcome and results of the organization's processes before the process is completed. This prediction can include the prediction of the final result, the next event, the time remaining until the completion of... 

    Operations Optimization in Supply Chain Systems using Simulation and Reinforcement Learning

    , M.Sc. Thesis Sharif University of Technology Mahmoudi, Farzaneh (Author) ; Hassan Nayebi, Erfan (Supervisor)
    Abstract
    The inventory costs constitute a significant portion of the supply chain costs. Therefore, choosing an optimal inventory policy for orders is of great importance. The aim of this research is to find the optimal inventory policy for a distribution center in a three-tier supply chain consisting of a manufacturer, a distribution center, and a retailer. This research simulates a supply chain in agent-based framework and optimizes it using reinforcement learning. The optimization KPI in this research is the mean daily cost of the supply chain. Finally, the result obtained from reinforcement learning is compared with the optimized result of AnyLogic and the mean daily cost in the model optimized... 

    Predictive Process Monitoring Based on Optimized Deep Learning Methods

    , M.Sc. Thesis Sharif University of Technology Alibakhshi, Alireza (Author) ; Hassannayebi, Erfan (Supervisor)
    Abstract
    Business processes are an essential part of every business as they provide insights on how to optimize and make them more efficient. Predictive Business Process Monitoring has garnered significant attention in recent years due to its capability to forecast process outcomes and predict the next activity within an ongoing process. In the last few years, there have been works that focused on deep learning and its applications in predicting the next activity. Some research used Long Term Short Memory, while others used Convolutional Neural Networks. However, long term short term memory models have the constraint of relatively slow training, while Convolutional Neural Networks are fast but may... 

    Customer Journey Analytics using Process Mining Based on the Markov Model

    , M.Sc. Thesis Sharif University of Technology Torabi Ardekani, Saba (Author) ; Hassan Nayebi, Erfan (Supervisor)
    Abstract
    The analysis of customer journeys has gained significant attention due to the critical role of customer behavior data in enhancing business decision-making and formulating strategies for customer acquisition and retention. By segmenting customers based on their journey patterns, businesses can offer personalized recommendations, thereby improving customer engagement and loyalty. Additionally, predicting the next steps in a customer’s journey based on historical data allows for timely and appropriate interventions at various touchpoints. By understanding where customers are in their journey, businesses can provide targeted recommendations that increase the likelihood of converting potential... 

    A System Dynamic Simulation Approach to Investigate Economic And Environment Factors Based on VUCA framework: A Case Study in Petrochemical Industry

    , M.Sc. Thesis Sharif University of Technology Monfaredi Jafarbagi, Aoun (Author) ; Hassannayebi, Erfan (Supervisor)
    Abstract
    To maintain adaptability, businesses should anticipate changes in their environment. The commonly employed forecasting method within corporate circles is the bottom-up approach, which relies on historical data for projecting future trends. However, research suggests that this approach often falls short of accurately reflecting real-world events. This has led to the adoption of dynamic systems modeling, a technique grounded in the assumption of stable conditions. This method effectively replicates the system's current state, thereby assisting in predicting future behaviors over a longer timeframe. The dynamic systems modeling approach was employed in this study, underscoring the imperative... 

    Discovering and Improving the Processes of an Iranian Psychiatric Hospital Using Process Mining

    , M.Sc. Thesis Sharif University of Technology Roshan, Mohammad Amin (Author) ; Hassan Nayebi, Erfan (Supervisor)
    Abstract
    Providing quality hospital services depends on the efficient and correct implementation of processes. Therapeutic care processes are a set of activities that are carried out with the aim of diagnosing, treating and preventing any disease in order to improve and promote the patient's health. The purpose of this study is to use process mining techniques to discover and improve healthcare processes. The case study of this research is a psychiatric hospital in Shiraz. The approach implemented in this research consists of three main stages including data pre-processing, model discovery phase, and analysis phase. Three algorithms including Heuristic Miner, Inductive Miner, and ILP Miner were used... 

    The investigation of natural super-cavitation flow behind three-dimensional cavitators: Full cavitation model

    , Article Applied Mathematical Modelling ; Volume 45 , 2016 , Pages 165-178 ; 0307904X (ISSN) Kadivar, E ; Kadivar, Erfan ; Javadi, K ; Javadpour, S. M ; Sharif University of Technology
    Elsevier Inc  2016
    Abstract
    In this study, natural super-cavitating flow around three different conical cavitators with wedge angles of 30°, 45° and 60° is investigated. We apply the k−ϵ turbulence model and the volume of fluid (VOF) technique to numerically study the three-dimensional cavitating flow around the cavitators. The turbulence approach is coupled with a mass transfer model which is implemented into the finite-volume package. Simulations are performed for different cavitation numbers. Finally, the effects of some important parameters such as the cavitation index, inlet velocity, Froude number and wedge angle of cavitators on the geometrical characteristics of the super-cavities are discussed. Our numerical... 

    Analysis and Improvement of Agile Software Development Process Using Process Mining and Machine Learning Algorithms

    , M.Sc. Thesis Sharif University of Technology Fardipour Asl, Mohsen (Author) ; Hassan Nayebi, Erfan (Supervisor)
    Abstract
    In the competitive world of software development, IT product development teams face numerous challenges and issues within business processes. In recent years, the combination of process mining and machine learning algorithms to optimize software development processes has gained attention. However, there is still a lack of a comprehensive model for identifying and conducting root-cause analysis of problems and providing solutions based on them in agile software development systems. The aim of this research is to find a solution for identifying and addressing issues in the software development process by modifying the change request workflow and examining various aspects of incidents. To... 

    Improve Performance of Process Mining Algorithms in Low-Level Event Log with Machine Learning Methods

    , M.Sc. Thesis Sharif University of Technology Choopannezhad, Mahsa (Author) ; Hassan Nayebi, Erfan (Supervisor)
    Abstract
    This thesis abstract addresses the use of process mining techniques when event data is stored at varying levels of granularity. While most techniques assume that events have the same level of granularity, real data is often stored differently. Pre-processing techniques allow for appropriate summarization of the data, which simplifies the output while retaining important process details. The goal is to ensure an interpretable output for stakeholders and different business teams without losing critical process points. However, adding new data as a feature to the dataset can be expensive, and at times, infeasible. Therefore, existing data is the only solution. To overcome this challenge, this... 

    Simulation of SO2 absorption in a venturi scrubber

    , Article Chemical Engineering Communications ; Volume 197, Issue 7 , Feb , 2010 , Pages 934-952 ; 00986445 (ISSN) Taheri, M ; Mohebbi, A ; Taheri, A ; Sharif University of Technology
    2010
    Abstract
    In this study, a three-dimensional mathematical model, based on a nonuniform droplet concentration distribution, has been developed to simulate gas absorption in a venturi scrubber. The mass transfer process was illustrated by assuming the liquid phase as a combination of droplets and film. The flow, just as the annular two-phase flow, includes a flow of liquid film layer on the walls and a flow of gas and liquid drops in the core. Peclet number was determined using experimental data reported by Viswanathan et al. (1984) for distribution of droplets across the cross section of the scrubber. The mathematical model for gas absorption was justified by comparing the theoretical predictions with... 

    Robust Markov Decision Processes and Applications in Mathematical Finance

    , M.Sc. Thesis Sharif University of Technology Soori, Mohammad (Author) ; Fotouhi Firouzabadi, Morteza (Supervisor) ; Salavati, Erfan (Supervisor)
    Abstract
    Dynamic portfolio optimization is one of the prominent problems in financial mathematics, for which numerous theories have been proposed to solve it. One of the solutions to this problem is the use of reinforcement learning. The main challenge with this method is that most reinforcement learning algorithms require a large amount of data, and therefore, the necessary data is often obtained not from the real world, but through simulations by estimating the parameters of a model. However, the approximation error of the parameters can propagate through the final solution, leading to inaccurate results. One approach to addressing this issue is the use of robust Markov processes and robust... 

    Simulation-Based Optimization for IoT-Enabled Epidemic Patients Care Systems

    , M.Sc. Thesis Sharif University of Technology Bisheh Niasar, Mohammad Amir (Author) ; Hassan Nayebi, Erfan (Supervisor)
    Abstract
    This research focuses on examining and improving healthcare systems, particularly during crises and pandemics. Following disasters such as natural calamities and pandemics like COVID-19, healthcare systems face significant challenges due to the increased demand for medical services, creating a substantial threat to the population in the affected regions. This study emphasizes the importance of utilizing modern technologies such as the Internet of Things (IoT) and telemedicine systems in alleviating the pressure on healthcare systems. A combined approach of prediction and multi-objective optimization based on simulation is proposed in this study to improve resource allocation and demand... 

    The effect of prestrain temperature on kinetics of static recrystallization, microstructure evolution, and mechanical properties of low carbon steel

    , Article Journal of Materials Engineering and Performance ; Volume 27, Issue 5 , 2018 , Pages 2049-2059 ; 10599495 (ISSN) Akbari, E ; Karimi Taheri, K ; Karimi Taheri, A ; Sharif University of Technology
    Springer New York LLC  2018
    Abstract
    In this research, the samples of a low carbon steel sheet were rolled up to a thickness prestrain of 67% at three different temperatures consisted of room, blue brittleness, and subzero temperature. Microhardness, SEM, and tensile tests were carried out to evaluate the static recrystallization kinetics defined by the Avrami equation, microstructural evolution, and mechanical properties. It was found that the Avrami exponent is altered with change in prestrain temperature and it achieves the value of 1 to 1. 5. Moreover, it was indicated that prestraining at subzero temperature followed by annealing at 600 °C leads to considerable enhancement in tensile properties and kinetics of static... 

    An investigation on tensile properties of coiled carbon nanotubes using molecular dynamics simulation

    , Article Diamond and Related Materials ; Volume 74 , 2017 , Pages 154-163 ; 09259635 (ISSN) Shahini, E ; Karimi Taheri, K ; Karimi Taheri, A ; Sharif University of Technology
    Elsevier Ltd  2017
    Abstract
    A coiled carbon nanotube (CCNT) can be formed from the distortion of parent toroidal carbon nanotube with a uniform pitch length and a uniform spring rise angle. In this research molecular dynamics simulation was carried out to assess the tensile properties of three CCNT having indexes of (3,3), (4,4), and (5,5). The results indicated that Stone-Wales defects are necessary for thermodynamic stability of the CCNTs. The stress-strain curves showed that the yield stress, yield strain, and failure strain are decreased with increase in temperature. The force-displacement curves revealed that the spring constant of these materials is highly depended on the tube diameter and rising angle, while it... 

    Microstructural evolution, mechanical properties, and corrosion resistance of a heat-treated Mg alloy for the bio-medical application

    , Article Journal of Magnesium and Alloys ; Volume 7, Issue 1 , 2019 , Pages 80-89 ; 22139567 (ISSN) Janbozorgi, M ; Karimi Taheri, K ; Karimi Taheri, A ; Sharif University of Technology
    National Engg. Reaserch Center for Magnesium Alloys  2019
    Abstract
    During the recent years, some Mg based alloys have extensively been considered as a new generation of degradable and absorbable bio-medical materials. In this work, the Mg–2Zn–1Gd–1Ca (wt%) alloy as a new metallic bio-material was produced by the casting process followed by the heat treatment. The samples of the alloy were solution treated at temperatures of 500, 550, and 600 °C and then quench aged at temperatures of 125, 150, and 175 °C. The results of SEM-EDS examinations indicated that the alloy microstructure consists of α-Mg matrix and the Ca2Mg6Zn3 and Mg3Gd2Zn3 secondary phases. With regard to the results of Vickers hardness test, the temperatures of 500 °C and 150 °C were selected... 

    Business Processes Deviation Analysis Using Process Mining Algorithms

    , M.Sc. Thesis Sharif University of Technology Attarzadeh, Milad (Author) ; Akbari Jokar, Mohammad Reza (Supervisor) ; Hassannayebi, Erfan (Co-Supervisor)
    Abstract
    Deviations in business processes consistently impose significant financial and temporal costs on business owners and can lead to decreased customer satisfaction with organizations. Therefore, timely identification of deviations is a crucial and significant issue for business process managers. While extensive research has been conducted on the detection of antecedent deviations, predicting deviations before they occur—which could facilitate preemptive actions to prevent these deviations—has received less attention. In this context, the aim of this study is to predict two types of process deviations—temporal deviations and Rework deviations—using machine learning and deep learning algorithms,... 

    A study of hyperelastic models for predicting the mechanical behavior of extensor apparatus

    , Article Biomechanics and Modeling in Mechanobiology ; Volume 16, Issue 3 , 2017 , Pages 1077-1093 ; 16177959 (ISSN) Elyasi, N ; Karimi Taheri, K ; Narooei, K ; Karimi Taheri, A ; Sharif University of Technology
    Springer Verlag  2017
    Abstract
    In this research, the nonlinear elastic behavior of human extensor apparatus was investigated. To this goal, firstly the best material parameters of hyperelastic strain energy density functions consisting of the Mooney–Rivlin, Ogden, invariants, and general exponential models were derived for the simple tension experimental data. Due to the significance of stress response in other deformation modes of nonlinear models, the calculated parameters were used to study the pure shear and balance biaxial tension behavior of the extensor apparatus. The results indicated that the Mooney–Rivlin model predicts an unstable behavior in the balance biaxial deformation of the extensor apparatus, while the... 

    Estimating Evaporation from Non-Agricultural Areas (Bare Soil and Range Land) in the Lake Urmia Basin

    , M.Sc. Thesis Sharif University of Technology Abdoli, Mohammad (Author) ; Tajrishi, Masood (Supervisor) ; Jalilvand, Ehsan (Co-Supervisor) ; Haghighi, Erfan (Co-Supervisor)
    Abstract
    Evaporation is one of the main parameters of the mass transfer from earth to the atmosphere, which annually transfers more than 65 billion cubic meters of water. Worldwide, evaporation consumes 25% of the energy input and plays a key role in restoring 60% of the precipitation to the atmosphere. Small changes in the water budget and evapotranspiration (ET) in arid and semi-arid areas can cause a large change in ecosystem health. Lake Urmia Basin has been taken into huge consideration due to steepest decline in lake level in the last three decades. Estimating evapotranspiration of this basin is important for the study of agricultural water consumption, hydrological modeling, water resources...