Sharif Digital Repository

With the explosion of mobile smart devices, many computation intensive applications have emerged, such as interactive gaming and augmented reality. Mobile edge computing (EC) is put forward, as an extension of cloud computing, to meet the low-latency require- ments of the applications. In mobile edge computing systems, an edge node may have a high load when a large number of mobile devices offload their tasks to it. those offloaded tasks may experience large processing delay or even be dropped when their deadlines expire. Due to the uncertain load dynamics at the edge nodes, it is challenging for each device to determine its offloading decision (i.e., whether to offload or not, and which... 

Expansions of large urban areas, as well as increase in the rate of car ownership, has given rise to the urban traffic congestion. One of the major approach to cope with the congestion issue is named Transit Oriented Development (TOD), which will cause changes in trip departure times, route choice, mode choice, and trip destinations. TOD also affects the land use in long-run periods. The goal of this study is to clarify the long-term impacts of TOD on land use and find the appropriate transit projects in order to abate the drawbacks of changes in land us. Land use/ transportation has been the subject of many recent studies. One of the previous studies investigates land use and transportation... 

In recent years, environmental issues has been gaining a great deal of attention in the field of Supply Chain and Supplier Selection. In this research, we first review the current literature and then we try to find the research gap in this area. According to the studies done in this area, no research on supplier selection and optimal order allocation to the suppliers have simultaneously investigated environmental issues, the possibility of storage, green routing of vehicles, purchasing discount, multi-product, and multi-period state in a green supply chain. Therefore, in this study, a multi-objective mathematical model is proposed for supplier selection and optimal order allocation in a... 

In this study, given the increasing challenges urban and intercity transportation face in the modern world, including population growth, urban development, and environmental concerns, an innovative approach to optimize the use of car-sharing vehicles is presented. The research aims to develop a multi-objective mathematical programming model for the optimal allocation of car-sharing vehicles, considering key factors such as transportation costs, travel time, and environmental pollution. This seeks to reduce costs, increase efficiency, shorten travel times, and contribute to environmental sustainability. Initially, a thorough literature review was conducted to provide a comprehensive... 

The process of portfolio construction and optimization can be broken down into three main steps: selecting appropriate assets, allocating capital, and monitoring and adjusting the portfolio. This study focuses on evaluating the performance of the Hierarchical Risk Parity (HRP) method for capital allocation in investment portfolios, specifically in Iran’s capital market. The aim is to enhance the method's effectiveness by implementing alternative correlation calculation approaches, such as Wavelet and Chatterjee correlations. The study utilizes three different portfolios containing assets from the Tehran Stock Exchange, the US stock market, and the cryptocurrency market. The primary objective... 

One of the most important issues that an organization faced with is resource management. The proper resource management has the great rule in organization cost reduction. One of the most efficient processes in resource allocation is auction and there is different auction with different mechanism and goals. In an auction there is a set of items and a set of bids, and the task of auctioneer is matching items with suitable bids. Each bid consist of desirable items and the bidder value of that items. In an auction process, after mechanism design of auction and auction implementation we must identify the winners of auction and this is a hard problem even in simple auction.
In this study we... 

This study proposes a deep reinforcement learning approach to solve a perishable inventory allocation problem in a two-echelon supply chain. The inventory allocation problem is studied considering the stochastic nature of demand and supply. The examined supply chain includes two retailers and one distribution center (DC) under a vendor-managed inventory (VMI) system. This research aims to minimize the wastages and shortages occurring at the retailer's sites in the examined supply chain. With regard to continuous action space in the considered inventory allocation problem, the Advantage Actor-Critic algorithm is implemented to solve the problem. Numerical experiments are implemented on... 

In the last decade, emergency department (ED) overcrowding has become a national crisis for the US healthcare system. Increasing mortality rates, decreasing quality of care, financial losses due to walkouts, and ambulance diversion are some of the consequences of ED overcrowding. Given the increasing demand in terms of ambulance utilization which we can see an instance of it in the COVID-19 pandemic, being able to allocate service requests to EDs efficiently, becomes a key function of emergency medical services. in this investigation, an algorithm of deep reinforcement learning called deep Q-learning is used to address this problem and to assign ambulances to ED's appropriately. under... 

Due to multiple transmit-receive channels, the signal model in a MIMO radar system is usually described by high dimensional data structures. However, the desired target space (e.g. range-azimuth domain) which shall be estimated, is mainly sparse (the number of existing targets is usually small). This observation has promoted the use of sparse recovery methods in multi-target detection and estimation in such radar systems which led to introducing the concept of compressive sensing (CS) based MIMO radars. Successful implementation of CS techniques for recovery of radar scenes (for target detection/estimation) from the received noisy measurements strongly entails that the associated sensing... 

Simulation optimization has been one of the most important topics in recent years. It is especially useful when the objective function cannot be computed directly or some of the parameters are stochastic. Buffer allocation problem is one of the important problems related to production lines. In this problem the objective is to determine the buffers between workstations so that the throughput is maximized. Non-linear and combinatorial nature of the problem, stochastic factors like machine breakdown or processing times and most importantly lack of a distinct relation for the objective function are the reasons of using simulation ... 

One of the most efficient techniques deployed for end-stage renal disease remedy is kidney transplantation, but in this case, we commonly encounter with the problem of gap between the demand of patients and supply of donors. In the majority of models has been proposed until now, either kidney exchange technique in a pool of incompatible pairs or kidney allocation system from deceased donors to waiting list is recommended. In this research, in order to enhance kidney transplantation plans, first, a hybrid conceptual model is proposed. Then, its mathematical model is discussed, in which some of the transplantations are selected from kidney allocation system before injecting to the pool of... 

In this thesis, we propose a processor allocation mechanism for run-time assignment of a set of communicating tasks of input applications onto the processing nodes of a Chip Multiprocessor (CMP), when the arrival order and execution life-time of the input applications are not known a priori. This mechanism targets the on-chip communication and aims to reduce the power and latency of the Network-on-Chip (NoC). In this work, we benefit from the advantages of non-contiguous processor allocation mechanisms, by allowing the tasks of the input application to be mapped onto disjoint regions (sub-meshes) and then virtually connecting them by bypassing the router pipeline stages of inter-region... 

This research aims to explore the effectiveness of past tariff evolutions in shaping firms' response to current input prices. Additionally, it investigates how asymmetric fuel pricing across different industries influences overall industry efficiency and prosperity. Furthermore, the study examines the impact of fuel subsidies on the equilibrium distribution of companies independent of welfare decline. In Chapter 1, utilizing microdata from Iranian industrial workshops between 1386-1396 (2007-2017) A key finding is that new firms exhibit a significant and stronger reaction to energy price variations compared to other firms when it comes to technology choices.Chapter 2 presents a structural... 

Undoubtedly, energy is one of the most important components of progress in any country. Despite some existing imagery about the future of human access to new and non-renewable energy sources, it is now safe to say that energy is a limited resource that is becoming increasingly difficult to access over time. Utilizing the experiences of developed countries in the field of optimal management and advancing strategic goals in the field of energy is one of the necessities of the country today. In this dissertation, using the meta-combined method, the experiences of the United States of America, China, Saudi Arabia, Norway, Singapore and India as countries that each have one of the advantages in... 

The Emergency Medical Services (EMS) have a major role in decreasing the mortality rate and reducing the non-reversible effects of injuries by on time care to patients and transporting them to hospitals if it is needed. Since there is an important goal directly related to the human life, any research or study to improve the performance of EMS is highly recommended. One of the most important parameters in evaluation of EMS is to measure the coverage time of a demand. The locations of EMS play substantial role to decrease the response time. So the locations of EMS stations are very important especially in large and populated cities. Mainly, there are three problems that EMS managers should... 

Hub and Spoke networks come into play when considering direct link between all origins and destinations is either impossible or expensive in a transportation system. In this kind of problems, some nodes are chosen as hub from all origin and destination nodes to collect flows and then distribute them. Implementing hub network leads to minimizing transportation cost, sorting flows and conveying them in economies of scale. Otherwise, shipping flows directly may cause decreasing the travelling distance and the delivery time consequently. In this dissertation, combination of hub network and direct shipment is investigated. To obtain the optimal hub locations and direct links between non-hub nodes... 

One of the main applications of revenue management is in healthcare industry. By combining these two concepts, subjects such as patient allocation and scheduling and no-show rates were developed in the literature. Up until now, allocation and scheduling were considered separately in the literature. Also, no-show rates were predicted using regression models and data mining tools and these predictions were rarely used in scheduling systems. In this thesis, we combined allocation based on patients’ insurance type with scheduling based on patients’ no-show rates. Also, patients’ no-show rates were predicted and these rates were used in the proposed scheduling model. Firstly, the integrated... 

Pricing and Revenue Management in systems that offer services in subscription as well as pay-per-use format simultaneously is one of the most significant challenges in service companies. One of the main criteria in these systems is keeping the loyal customers and attracting more subscribers. Pricing and capacity allocation are decisions to be made in such systems considering customer’s behavior. In this research, we consider a service system with subscription and pay per use options to analyze the price and capacity allocation based on customer’s bahvior. The Loss Aversion theory is assumed for customer’s behavior and its effect on decisions is analyzed. A greedy algorithm as well as a smart... 

It has been for several years that researchers and pioneers in wealth management have suggested a variety of solutions to investors, in order to allocate their assets. One level of such suggestions is to form a portfolio of stocks. But when it is decided to choose between different asset classes, the solution is more complex. Such questions must be answered: •Is it the best pair to have a portfolio of 70% stock- 30% real estate, or vice versa? •How would it change by possibility of investing in gold market? It is obvious that exact knowledge about investor’s goals, restrictions, and preferences (which are called Investment Policy Statement or IPS) is prerequisite of answering to these... 

One of the topics that has been given great consideration after restructuring and smart grid emergence, is loss management. This subject is specifically important in distribution systems, which have been reported to have 70% of the total loss in power systems. In this thesis, distribution loss is studied and its affecting factors are analyzed. Then loss optimization and loss cost allocation to distribution consumers are studeid. In order to acheive these two goals, it is neccessary for the distribution system to have the capabilities of a smart grid. The subjectof distribution reconfiguration is duiscussed as one of the loss reduction methods. Traditional reconfiguration problem trend...