Sharif Digital Repository

Proton therapy is an advanced method of cancer treatment that has the ability to provide better protons than other radiation therapy methods. Even though the charged particles have superior characteristics and their biological properties are more than the deviations in treatment design. In order to check the uncertainties in hadron therapy and reduce the side risks, there is a need for methods to monitor the range during radiation therapy. Considering that the charged particles are in the tissue, the monitoring method should be able to collect the secondary particles produced during the interaction of the primary beam with the tissue. Currently, positron emission tomography (PET) is the only... 

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... 

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... 

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... 

This research examines the attributes, themes, and topics discussed in electronic word-of-mouth (e-WOM) generated in TripAdvisor for robotic hotels in comparison to traditional ones. The first objective is to explore the themes and topics within TripAdvisor negative e-WOMs for both types of hotels and analyze how these topics differ between the two types of hotels, using the Latent Dirichlet Allocation (LDA) method. The research shows that which topics are mostly discussed in TripAdvisor negative e-WOMs for both types of hotels. Additionally, the research explores whether different themes, topics, and attributes have varying effects on user ratings in traditional hotels versus robotic ones,... 

This study explores topics discussed in positive eWOM of robotic and conventional hotels through a comprehensive analysis of online reviews using Latent Dirichlet Allocation (LDA). LDA is an advanced topic modeling technique. To uncover topics discussed in eWOM of robotic hotels and conventional hotels, and then compare them to see if there are any meaningful statistical differences between them, three separate LDA models were implemented on reviews of robotic hotels, conventional hotels, and the overall rereviews of all hotels, respectively. The results reveal that “service quality and overall atmosphere” is the most common topic discussed considering both hotel types, with key themes... 

This thesis examines the impact of electronic word-of-mouth (e-WOM) on product demand forecasting, specifically in the context of video game consoles. This study examines the importance of emotion-based topics and their impact on demand forecasting at two stages of the product life cycle: pre-launch and post-launch. Using sentiment analysis and topic modeling, this study uncovers product sales drivers and captures evolving consumer sentiment throughout the product lifecycle. By integrating insights from diffusion theory and consumer information search theory, this research contributes to the field of demand forecasting using social media data. This research shows that by using the topics... 

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... 

A novel internetworking paradigm, software-defined exchange (SDX), allows multiple independent administrative domains to share computing, storage, and networking resources. Although the term SDX is very recent, the concept has already been used by many distinct disciplines.We argue that the advent of Software Defined Networking (SDN) provides a unique opportunity to effectively detect and contain network security problems such as DDoS attacks. DDoS attacks can easily exhaust the controller's or the switches' computing and communication resources and hence, breakdown the network within a short time. In this thesis we extend these functionalities with an efficient, scalable and light weight... 

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... 

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... 

Reservoir simulation is a useful tool for efficient reservoir management and protective exploitation of non-renewable hydrocarbon resources as the main supplier of development programs in the country. Due to the nature of underground hydrocarbon reservoirs, the simulation faces several challenges, both in rock and fluid parts. These challenges should be overcome in order to provide reliable results from simulations. One of the major challenges pertaining to rock, is large discontinuous variations accompanied by anisotropy of rock permeability fields which causes numerous problems when governing equations are solved numerically. A viable numerical procedure shall account for complex reservoir... 

Focusing on developing the EEPS (Energy Electric and Power System) based on the SG (Smart Grid) infrastructure to achieve implementation of EI (Energy Internet) ultimately, in order to analyze and manage the energy/power consumption, requires a robust embedded EMS (Energy Management System) to implement real-time LF (Load Forecasting), prevent the power waste and realize consumption management which eventually leads toward the smart industries/buildings. STLF (Short Term Load Forecasting) is an essential component that an industrial plant requires to manage the power, regarding the load fluctuations during production, and compulsory requirement of cost mitigation. This thesis, in order to... 

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... 

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...