Sharif Digital Repository

In today‘s world, the need for travel to different places for various reasons like politics, business and entertainment is unavoidable. This demonstrates the importance of the airline industry and the attention is achieved from the society. Different airlines try various strategies to satisfy more customers of this industry and of course more benefit would arise. These strategies would work more efficiently based on the outcome of a sound research on the exact needs of the customers, their perceived quality and expectations, and the gaps between the two and how they can be filled. This research follows the aim of understanding customer satisfaction for airline industry in Kish Island .In... 

By an increase in demands for multimedia services of mobile, wireless networks shall provide Quality of Service (QoS) requirements for users moving in cells. Multimedia services such as voice, data and image own different features and every QoS are different from the other due to delay and demand for bandwidth.
This thesis presents a new model of call admission control which consists of a few key elements for protecting the network in different conditions of workload in a manner that calls blocking /dropping are kept under desired level. This model consists of two traffic classes of voice and data in order to give apriority to handoff call over new call, the parameters in this model are... 

Nowadays, in communication industry, specially data network, in which service quality is a serious parameter, request for making connection with appropriate quality (Proportionate to demands) and necessity of clarification of obligations of service providers and customers, as well as customer awareness of submitted materials and offering various services with different qualities & costs, led service providers, specially IP based networks, to make agreements with their customers, entitled service Level Agreement (SLA). The SLA specifies the service type, mutual obligations, related parameters, measuring methods, violation threshold, penalties and loss compensation. Whereas, applying... 

Today service sector is an important part of economy in many countries and it accounts for a great portion of GDP in developed countries. The importance of the service sector has led to an expansion in research worldwide on services. Service has some unique specifications that make it different from product and research in this field is more challenging than production field. Pricing is one of the great challenges in service sector. Due to its intangibility and perishability, managing and pricing of service is complicated and ervice firms consistently seek for method and approaches to better manage their demand, capacity and prices. Advance sale is an effective approach which is commonly... 

Multicasting has gained a lot of research attentions in facilitating group communications in wireless networks. Applying multicast mechanisms in Wireless Mesh Networks, brings a lot of benefits to these networks. In our research, we have introduced Cost-aware On-Demand Multicast Routing Protocol (C-ODMRP) as an extension of ODMRP that supports QoS provisioning for high quality applications in WMNs. In C-ODMRP, the nodes are prevented from applying the links that do not meet the QoS requirements. The multicast receivers are provided with resource-aware information to efficiently compute the cost of the routes when multiple routes from source to destination nodes are established. C-ODMRP takes... 

Next generation wireless networks support high data rates and QoS parameters of various users. OFMDA is a popular transmission technique to support high rate transmission, however in multi-access environments, it relies on careful resource allocation to guarantee the desired QoS parameters. While resource allocation in centralized scenarios such as cellular networks is relatively straightforward, the problem becomes quite complex in distributed scheduling of multiple access environments. One key resource is power assigned to each sub-channel which determines the overall transmission capacity.In this dissertation, firstly we introduce some cross layer QoS provisioning or power efficient QoS... 

Recently studies have shown that about 50% to 70% of voice calls and other traffics are used in indoors by users. Due to the growing need to increase the rate of communication networks and macrocells resource constraints in providing this need, the idea of using femtocells was proposed. These cells transmite traffics via IP network to the operator. This would reduce the load of macrocells and thereby increase the rate of network users. So the idea of using femtocells inside macrocells was introduced. In addition to increasing the rate of network, the other advantages of using femtocells are lower cost, lower power consumption and better user channel condition. The important challenge of... 

In this work we have investigated the methods of providing quality of service in cognitive radio networks. At first, we have explained the various algorithms of providing BER quality of service in wireless networks. Especially we have explained those algorithms which are known as the distributed power control algorithms. Then we have introduced methods of using adaptive modulation and we have used this kind of modulation to provide delay quality of service in cognitive radio networks. We have done this by maximizing the sum of effective capacities of secondary links under the power constraints and also the interference constraints set by the primary receivers. Finally, we have introduced... 

Analysis of traditional spectrum allocation schemes shows underutilization of radio spectrum. This is main motivation behind deployment of cognitive radios and improving spectrum efficiency. One of the most important issues in cognitive radio networks is to guarantee quality of service (QoS) constraints for the primary users. Another problem which must be considered during network design is to design distributed algorithm with few amount of control messages. However, there is a tradeoff between to be distributed of algorithm and to be efficient. We have used game theory to analyze convergence, effectiveness and uniqueness of stable point of network.
This thesis is organized in two parts.... 

In auction-based cloud investment environments, consumers desire the least possible cost and high satisfaction, while providers seek strategies to maximize profit and return on investment. In these environments designing an adequate resource allocation that can satisfy both consumers and providers is of utmost importance. Yet, most available models in resource allocation focus on providers’ needs and do not concern themselves with the consumers. Therefore the present study aims to present an efficient and optimum model for resource allocation problem that takes into account various factors, e.g. resource price, service quality, reputation and fairness, and is capable of satisfying all honest... 

With significant advances in software development technologies in recent years, it is possible to have complex software applications, wich include large number of heterogeneous software components distributed over a large network of computers with different computational capabilities. To run such applications, their components must be instantiated on proper hardware resources in their target environments so that all requirements and constraints are met and some quality of service parametesrs (e.g.,reliability, load balancing, etc) are also optimized. This process is called software deployment. For large, distributed ,component-based applications¬ with many constraints and requirements, it ... 

Mobile Worldwide Interoperability for Microwave Access (Mobile WiMAX) is a wireless access technology based on IEEE 802.16e. Mobile WiMAX supports mobility and a wide range of Quality of Service (QoS) requirements for several applications. This wireless technology introduces handover mechanisms to avoid disruption of services running on Mobile Stations (MS) through moving. In this thesis, we have focused on balancing the load of the system, using handover mechanisms suggested by mobile WiMAX. The proposed algorithm, WQLB, concentrates on controlling the system load and keeping it in a balanced state by using a handover process. Also, the algorithm is designed to utilize resources... 

Recently there is a huge growth in industrial automation. Industrial automation is defined as trying to do some tasks automatically and without direct human intervention. Using industrial automation may help increasing efficiency, quality and safety. Industrial automation also could increase Competitiveness and flexibility of industries. In human life there is a large area of activities that automation could be used and different industries like oil and gas companies, electrical generation and distribution industries, medical companies, textile and other industries could use automation to increase their efficiency. But recently there is a growing demand for building automation and home... 

Achieving the required Quality of service (QoS) is a challenging task in the emerging next generation networked multimedia applications. Providing QoS guarantees becomes even more challenging when you add the complexities of wireless and mobile networks. An important aspect of wireless networks is their dynamic behavior. Especially when we need to transmit multimedia data over wireless networks, this problem becomes more significant. Live video with large end to end delay is meaningless and very low quality video is not satisfying. In recent years, a number of Protocols for providing guarantee of service are presented in the literature. These techniques include data link layer QoS schemes,... 

Communications in organizations have been one of the most important issues. To run the business processes, the company needs communication between units and customers. We provide a tool which can be used as an aid for network designers by guiding them with a framework. The resulting QoS parameters help to provide more alignment between the network and business requirements. The framework contains values for delay, loss and availability as three QoS parameters of the network used in the business process. The organizations business processes are used as a basis for the method which used in the tool. We use UML as the tool to model the business processes in the organization and the process is... 

The efficient scheduling of independent and sequential tasks on distributed and heterogeneous computing resources within grid computing environments is an NP-complete problem. Therefore, using heuristic approaches to solve the scheduling problem is a very common and also acceptable method in these environments. In this thesis, a new task scheduling algorithm based on bee colony optimization approach is proposed. The algorithm uses artificial bees to appropriately schedule the submitted tasks to the grid resources. Applying the proposed algorithm to the grid computing environments, the maximum delay and finish times of the tasks are reduced.Furthermore, the total makespan of the environment... 

The rapid growth of broadband wireless access (BWA) has increased the demand of new  application  such  as  VoIP,  video  conferencing,  online  gaming  each  of  which  has  different requirement for quality of service. Due to limited bandwidth provided for these networks,  one  of  the  most  important  issues  is  how  effective  we  manage  bandwidth  in  order to support requests. The quality of service is an important indicator of the effective management  of  bandwidth.  Using  mechanisms  of  call  admission  control is  a  commonly  accepted method for balance between quality of service and increase of utilization resource  in  cellular  mobile  networks.  In  fact, ...