Sharif Digital Repository

Matching theory plays an important role in analyzing economic behavior in social networks. The matching theory has application in marriage problems, kidney exchange, allocating workers to firms and etc. The main problem in matching theory is to design a mechanism such that it results in maximizing the welfare and it is incentive compatible, to tell the truth for each individual. In this thesis, we introduce a measure for comparing any two matchings and we investigate two matchings mechanisms under certain domains  

With ever-increasing usage of cloud pattern, resources allocation in cloud environments is drawing an emerging importance. Due to nature of cloud environment, and in particular the presence of independent selfish agents, game theory is used as a modeling and problem solving tool in this field. Most of current cloud providers, use static pricing and rather long contracts in their provisioning and allocation process, which is in contrast with cloud’s elasticity principles. Various studies in this area, use game theory, and provide dynamic allocation and pricing mechanisms in form of auctions. An important shortcoming of these studies is oversight of distribution in cloud environment. This... 

In this thesis, we study a queuing system with one server in which customers differ in both sensitivity to delay and willingness to pay. In this system, the server’s goal is to design a mechanism in order to maximize her revenue. It is worth to mention that nonlinear delay cost is implemented.Making use of the achievable region approach, we show that a well-designed menu of probabilistic admission control along with priority pricing contracts, may force customers to reveal their true valuations and at the same time induce customers that are more sensitive to delay to opt for higher priorities. Thus, the probabilistic admission control allows the server to identify the customers that are... 

Recently, computer scientists and economists have defined many joint problems and cooperate widely in various areas. Importance of this interconnection is clear for everybody, now. New works have been conducted, nowadays, to use the daily - increasing web-based social networks in viral marketing for improving companies profits. The main problem which is proved to be NP-Complete in this context is about discovering k most influential nodes in a network. In this dissertation, we generalize the problem to a group-based version and we we use group-based advertising to achieve our main goal. A new algorithm called Group-Based Diffusion technique is proposed in this thesis for solving this problem... 

In this project a knee prostheses wear testing simulator based on a parallel mechanism for applying forces and torques, is designed. First according to ISO 14243 standard required degrees of freedom and design constraints are determined and also regarding simulator requirements some considerations in design are outlined. Considering all of these parameters, literature has been searched for proper parallel mechanism and because no suitable parallel mechanism, which is a 3 DoF 2T1R paralle mechanism with rotational degree about z axis, has been found; several new designs of proper mechanism have been presented. Scoring different mechanisms according to outcomed parameters from standard and... 

The concept of Online-Distributed Mechanism Design, is taken from the two concepts of Online Mechanism and Distributed Mechanism and speaks of an environment which is dynamic when there is no trusted center to do the computation. This problem is stated in this thesis for the first time and by the thesis we gave the first results in some of the up coming fields of Online-Distributed Mechanism. These feilds would be defined by different assupmtions about dynamic environments and the way of distributing of computation among agents. We consider single valued preference domains in the absence of any trusted center and in the presence of an enforcer. Then we try to design truthful auctions for... 

In contrast to traditional Networks where a designer can specify an action plan for each agent, in a network with strategic agents, every agent acts selfishly and chooses his strategy privately so as to maximize his own objective. In this dissertation, we study problems arising in the design of static and dynamic networks with strategic agents. We consider two classes of design problems. In the first class, the designer utilizes her control over decisions and resources in the system to incentivize the agents via monetary incentive mechanisms to reveal their private information that is crucial for the efficient operation of the system. In this class of problems, we address two main challenges... 

Nowadays, the capacity of renewable energy sources in electrical grids and electricity markets has been grown. Due to the fluctuation of renewable energy sources, one of the main challenges of system operators is the managment of renewable energy uncertaintites impacts on the performance of frequency control systems. A method for solving this challenge is to develop the ancillary service markets, e.g., frequency reserve and frequency regulation markets. In this thesis, an optimal equilibrium of different forms of ancillary service markets are analyzed. In addition, a dynamic real-time and resilient market mechanism is developed to capture the strategic behaviors of players while the optimal... 

Nowadays, we observe the growth in the number of mobile smart phones. These smart phones have had an impressive progress in software and hardware. Many studies have focused on utilizing this new platform. One of these areas of research is collecting information from environment.Two major challenges for a successful crowdsourcing system are engaging a sufficient number of workers and validating of their registered data, which make the system more reliable. Collecting data from different points of a territory can be defined as some tasks and should be assigned to users near those tasks properly. Some users want a monetary reward for the cost they incur. On the other hand, information... 

In this study, we consider the fair division problem. In this problem, a heterogeneous resource must be fairly divided among a set of agents with different preferences.The resource can be either a divisible good (i.e., time, land), or a set of indivisible goods. When the resource is a single divisible good, the problem is commonly known as cake cutting. To measure fairness, several notions are defined, i.e., envy-freeness, proportionality, equability, maximin-share. In this thesis, we first give a formal definition of these notions. Next, we present our results for envy-freeness and maximin-share.First, we prove the existence of an allocation that guarantees each agent a factor 3/4 of his... 

In Spatial Voting Theory, distortion is a measure of how good the winner is. It is proved that no deterministic voting mechanism can guarantee a distortion better than 3, even for simple metrics such as a line. In this study, we wish to answer the following question: how does the distortion value change if we allow less motivated agents to abstain from the election? We consider an election with two candidates and suggest an abstention model, which is a more general form of the abstention model proposed by Kirchgassner. We define the concepts of the expected winner and the expected distortion to evaluate the distortion of an election in our model. Our results fully characterize the distortion... 

Business incubators admit young startups and help them grow by providing them with a number of services. The startups are put through an admission process, and the incubator is not fully aware of the quality of the startups she is admitting. On the other hand, once inside the incubator, a startup may choose not to exert a high level of effort, as the incubator cannot fully monitor its behaviour. In other words the incubator faces a problem of adverse selection plus moral hazard.Adverse selection and moral hazard between investor and investee (which is not dissimilar to the relationship between incubator and startup) has a vast literature. However, one important difference is that in the... 

Mobile Ad hoc networks or MANETs consist of autonomous selfish nodes, which usually have a limited source of energy and choose their own transmission power independently. Nodes are mobile; hence the network topology changes continuously in time, therefore a topology control protocol is required to preserve the network connectivity and to adjust the transmission range of the nodes. Also in the absence of any infrastructure in the network, since the energy source of each node is limited and nodes are not eager to consume it for others, in order to stimulate the selfish nodes to cooperate to provide network services (such as relaying data packets) , we need to exert an incentive mechanism in...