Sharif Digital Repository

The Revenue management concept has been studied and noticed by researchers for more than forty years. Although the applications of revenue management grow in different industries continuously, airline industry which is the origin of this research area is the pioneer of developing and representing new models. In the last few years, there has been a trend to enrich traditional revenue management models. In this thesis we first, reviewed most aspects of revenue management studies especially in airline industry, then choice-based customer behavior concept is introduced. Also a case sample study in customer choice behavior has been developed with time scale considering and remodeled. According to... 

Examples from recent years, such as Covid-19 disease and earthquakes, show that disasters can have devastating effects on a community.These disasters are divided into two categories: expected and unexpected. decision makers cannot easily determine the time, severity and effects of them. Therefore, they must coordinate their decisions in the pre-disaster and post-disaster stages according to the incomplete information available, and according to the dynamics of the situation, quickly understand and interpret the connections between different decisions. Among the various approaches, the decision support system can explore the variable and unpredictable nature of such issues and enable decision... 

One of the primary concerns on many traditional capacitated facility location-network design problems is to consider costs of transportation and establishing of facilities in one single objective function. Considering a single objective in these problems may lead to misleading solutions due to the fact that the transportation costs should be considered in a short-term period of time, and therefore, the higher cost of establishing the facilities may unfairly dilute the role of the transportation cost. In this thesis, we introduce the capacitated facility location-network design problem with two separate objective functions. Moreover, in this problem, it is assumed that for connecting two... 

In this study, providing home care services by hospitals in the epidemic situations such as COVID-19 is proposed for the first time. Moreover, a mathematical formulation is developed to provide simultaneous decision-making about serving patients without COVID-19, scheduling nurses in the non-COVID-19 wards of hospitals, and scheduling and routing for nurses to serve patients at home. This problem aims to develop essential compatibilities to keep people safe and help continue vital healthcare services during the COVID-19 and similar pandemics. Accordingly, nurses' preferences, the number of available hospital beds, the patient-to-nurse ratio, the Unavailability of some nurses due to COVID-19,... 

reparedness and emergency procedure be devised in the event of,and prior to,a disaster. One of these disastersoften accompanying byhuge damages, losses and casualtiesisanearthquake. After such a disaster, several governmental and non-governmental organizations usually start relief operations. They commonly pursue their own agendas and use their own facilities and capabilities to help the people affected without pursuing a central plan. These disintegrated behaviors of involved organizations generate contradictory responses and result in either wasted resources or preventing equitable service for all affected people. Due tothe abovefact, this dissertation proposes amodel for improving... 

The human need for reliable and accessible energy sources for household, industrial, transportation, etc. caused the discovery of the first oil well to move towards exploitation and use of this large, cheap and available energy source, accelerated. With the start of this movement, oil and its products in the last two centuries have quickly established themselves as a major part of the energy basket of most countries in the world. The entry of crude oil and its products into the energy industry has faced new issues and challenges for decision makers in this field. One of the most important challenges has been the planning and management of the process of distribution and transfer of petroleum... 

In complex human social activities, practical problems involve more prominent uncertainty, and deterministic approaches of classical methods become powerless. In this research, a new method for human group decision making is presented by using heterogeneous incomplete uncertain preference relations. The uncertain multiplicative preference relations, uncertain fuzzy preference relations, uncertain linguistic preference relations, intuitionistic fuzzy preference relations and Interval
preference sequence can be included in this method.Our new method consists of nine steps. In the first step, decision-makers preferences in the form of heterogeneous comparison matrixes are driven.In the... 

In this thesis the capacity and flow assignment problems in worldwide webs is considered in order to minimize the total cost of networks and delays in network links. The main result of this problem is increasing the speed of message transmission and providing better quality of service delivery for network users. For pursuing these goals, Recursive Artificial Neural Networks is proposed for solving the problem and because of their high power and accuracy in reaching optimal solutions, they are convergent to optimal solutions very well. The method is tested on four different topologies and the results show that Recursive Artificial Neural Networks have high efficiency to reach optimal... 

Transportation Network Companies (TNC) like Snap and Tap30 are ride sharing platforms that connect drivers and passengers in real time using simple mobile phone applications. The most interesting feature of these platforms is that they do not hire drivers and allow them to choose when and where to offer a ride. Dynamic and fluctuating supply and demand, the necessity to forecast the changes, implementing them in ride pricing and driver-passenger assessment are considered as important challenges for such systems. In this research, first, we want to analyze the spatial structure of TNCs and then forecast network changes more precisely. The method used for forecasting is LASSO which is a... 

In recent years, simulation optimization methods have been developed to solve complicated problems that cannot be solved by mathematical programming methods. In simulation optimization methods, first the problem is modeled by simulation tools and then by applying optimization tools the optimal combination of input variables that optimizes the simulation output is determined. Although simulation optimization has attracted researchers’ attention in recent years, most of the works presented do not consider uncertainty in simulation models. This becomes our motivation in this study to develop uncertain methods in metamodel-based simulation optimization based on minimax methods that are... 

In this research, we try to coordinate a seller-buyer supply chain by using general side-payment contracts in order to gain the maximum possible chain profit. In this model, we take logistics costs into consideration for both buyer and seller and regard the final demand as a decreasing function of retail price which is determined by the buyer. Both parties aim to maximize their individual profits, so we must set contractual parameters in a way that these decisions become aligned with system optimal decisions and the chain surplus profit be assigned to chain members such that they have no intention to leave the coalition. To this aim, we suggest a side- payment contract which consists of... 

Patient scheduling is one of the most important problems in healthcare optimization which has been in center of attention in various environments including outpatient clinics and operating rooms. Effective scheduling systems have the goal of matching the demand with capacity so that resources are better utilized and patient waiting times are minimized. Furthermore, patient scheduling can be merged with another problem in which the main goal is to find the optimal sequence of a given list of patients. Moreover, there are several sources of uncertainty such as patients’ unpunctuality, absence, and service time in this problem resulting in having a very complex problem. In this research,... 

Layout design problem is to determine a suitable arrangement for the departments, so that the total costs associated with the flow among departments become least. Single Row Facility Layout Problem which is called SRFLP, is one of layout problems that has many practical applications. This problem and its specific scenarios is often used to model many of the raised issues. This is arrangements of n departments with a specified length in a straight line, so that the sum of the weighted distances between pairs of departments is minimized. We can say that SRFLP is one-dimensional version of the layout design problem and it tries to minimize the cost of communication between rectangular... 

Outpatient clinics always encounter a huge deal of demand and due to the variety of the services they provide and the existence of uncertainties, operation management is such a difficult task. This issue has made problems related to this issue popular among scientists and researchers. In this research, we are going to address several popular problems related to outpatient appointment scheduling. Initially, an M/M/c/K queuing system is developed in order to obtain the optimum scheduling window for different sub clinics. Secondly, the real demand for each sub clinics will be estimated using data analysis techniques for each 24-hour period. Having the results of the previous section, we build a... 

Transportation services enable economic growth of countries and account as a major part of Gross National Product (GNP) but on the other hand have negative environmental impacts including Greenhouse Gas (GHG) emissions, noise pollution and toxic effects on the ecosystem such as acid rain. The traditional objective of distribution management is usually minimizing economic costs. Given the existing environmental problems, ecological and social effects of transportation should be considered in addition to the conventional economic costs. In this study, a special type of Vehicle Routing Problem (VRP) with a heterogeneous vehicle fleet that in which environmental and traffic considerations taken... 

In literature, substantial works have been done on supply chain coordination. The majority of these works looking for a mechanism that enforces the supply chain members to follow strategies that produce the equilibria of an integrated supply chain, and most of this literature ignores competition between supply chains. In this thesis, we consider two distinct supply chains which compete to each other on the price. We present a method to calculate the equilibria for three structural forms. In the first form, two supply chains are integrated and in the second form, one of the supply chains is integrated and the other one is decentralized. Finally in the third form, both supply chains are... 

As time has passed, the cost of maintaining expert human resources has been increasing worldwide; as a result, factories and stakeholder has sought ways to exploit the expertise of their human resources as much as possible so they can reduce their costs and, of course, raise their profits. To achieve this, managers decided to assign their human resources to tasks that demands their expertise and knowledge and therefore provides added value for their companies; nevertheless, this decision needs proper alternatives to do routine and predetermined jobs as substitutions for expert human resources.As the technology and the science has been growing day by day, the use of robots has been extremely... 

Real-world decision-making problems usually have several criteria for evaluating the performance of alternatives. On the other hand, mathematical programming is a very practical tool for modeling and solving decision-making problems and multi-objective mathematical programming has high importance among researchers and managers in this field of study. However, the field of multi-objective integer programming is considered a rigorous category. Methods for solving these types of problems can be divided into three different approaches. There are few approaches and methods for solving multi-objective mixed-integer optimization problems in litreture.In this research, an extension of benders... 

Graph sum coloring problem is a special case of graph vertex coloring. Because of its applications in practical areas, especially in scheduling, many researchers have been attracted to it. In recent years, several heuristic and metaheuristic algorithms were applied to sum coloring problem. In this research a heuristic algorithm based on mini-max ant system and simulated annealing metaheuristics is used for graph sum coloring problem. This algorithm is tested on random graphs used in the literature and compared with prior algorithms. Results show that in many cases our proposed algorithm reaches the best known results or improves them  

In this study the predictive power of “Simple Moving Average” simulation for three month horizon is investigated. The purpose of the study is expressed in two hypotheses. The first hypothesis is that there is a significant difference in the prediction of stock price volatility by “Simple Moving Average” simulation with the “Weighted Moving Average” model prediction and the second hypothesis states that using “Weighted Moving Average” model we can forecast volatility stock price for the out-of-sample period. The research data includes a series of total stock price indices from 2013 to 2018 extracted from Tehran Stock Exchange (TSE). For “Weighted Moving Average” model, three normal...