Sharif Digital Repository

In this thesis, we study proof complexity conjectures and also introduce their mathematical logic equivalents in terms of provability and unprovability in strong enough first-order arithmetical theories. One of the most important conjectures in this theory is the following conjecture. The non-existence of an optimal proof system for propositional tautologies: In general, a proof system is a computable function in polynomial time such that its range is exactly the set of tautologies. We say proof system P, polynomially simulates proof system Q if and only if there exists a polynomial h such that for all tautologies such as A and for all proofs like a, if Qpaq A, then there exists a proof... 

In October 2022, the Ministry of Industry, Mine, and Trade announced the auctioning of 5,000 mines within a three-month period, an announcement that triggered significant reactions among environmental activists. Opponents argued that such an intense industrial expansion exceeds the ecological capacity of Iran’s environment. This study aims to demonstrate the impact of establishing active metal mines on wheat production efficiency as an ecosystem-dependent economic activity. To this end, mining-related data were obtained from issued exploitation permits, and agricultural expenditure and wheat production data were sourced from the “Survey of Production Costs of Major Crops.” The causal... 

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... 

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... 

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... 

The supplier selection problem is considered as one of the most strategic and critical issues for any organization. This issue is mainly relevant to traditional and manufacturing businesses. However, if we examine its relationship with the emerging concept of Vendor Acquisition, which has become increasingly significant in modern businesses and startups, the importance of supplier selection becomes even greater. Today, choosing the right supplier or vendor determines the level of success organizations achieve in any new project, and the performance of vendors plays a crucial role in shaping and directing these projects. This study aims to present a comprehensive framework for supplier... 

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... 

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... 

The increasing demand for urban logistics services and the growing customer expectations regarding delivery speed and quality have made the vehicle routing problem a critical operational challenge for logistics companies. In this study, the same-day pickup and delivery vehicle routing problem was investigated using real-world data from a logistics company in Tehran. For this purpose, a mixed integer linear programming model was presented with the aim of minimizing the total travel cost, fixed vehicle operating cost, and delay costs. The problem formulation considered open vehicle routing, pickup and delivery, same-day delivery, stochastic and time-dependent travel times, and heterogeneous... 

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... 

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... 

One of the main concerns of automakers over last few decades was reducing fuel consumption while increasing the efficiency of vehicle. Using Continously variable transmission in vehicles could lead to reaching better performance, improving fuel consumption, reducing emissions and increasing vehicle acceleration. In this thesis types of Continously variable transmissions are introduced with focusing on steel V-belt CVT by analyzing its performance in steady and transient conditions. Unlike flat belts, V-belts moves both radial and tangential over the driver and driven pulleys resulting more complex dynamic.The dynamics of these systems in transient conditions are analyzed in two different... 

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 foreign exchange market, commonly known as Forex, is one of the largest and most significant financial markets in the world, attracting the attention of numerous investors on a daily basis. One of the main challenges faced by traders in this market is the accurate prediction of currency prices. Although Forex market forecasting is highly popular, the inherent complexity of this market continues to make accurate prediction a persistent concern. In recent decades, remarkable advancements have occurred in the field of machine learning, particularly in deep learning. These developments have also influenced the Forex market, resulting in the publication of numerous research articles aimed at... 

Forecasting demand for fast-moving consumer goods (FMCG) is a fundamental yet challenging issue in retail management due to highly volatile demand, short product life cycles, low profit margins, and limited customer loyalty. Customer purchase behavior reflects their response to a set of concurrent product attributes in the retail environment; price, discounts, product placement, and other stimuli influence the final purchase decision not independently, but in combination and in interaction with related products. Therefore, modeling this behavior realistically requires considering the dynamic interactions among products, and relying solely on univariate time series analysis is insufficient.... 

In the age of information and technology, online stores have significantly expanded as one of the most prominent manifestations of e-commerce. With increasing competition among businesses, leveraging modern data mining techniques to identify potential customers, predict customer churn, and enable more precise targeting in direct marketing has become a necessity. This study integrates data mining methods with marketing concepts to analyze the behavior of online store customers using the RFM model (Recency, Frequency, and Monetary value of purchases) and employs the K-Means clustering algorithm to segment customers. Furthermore, to more accurately predict customer behavior, two modeling...