With the increasing demand on multimedia applications over the Internet, and the growing number of mobile smart devices people are using, it is helpful to develop a mobile network architecture that can support multimedia transmission without using infrastructures. We propose that service overlay networks over MANETs can serve as a supplement to the existing 3G/4G networks and Wi-Fi access point networks. In this thesis we present experiment results that show the feasibility of mobile service overlay networks to meet the requirements of multimedia streaming. And also, we improved one of the existing overlay protocols. The improved protocol takes physical location into consideration when establishing connections in the overlay network. It also limits the number of neighbors each node can have, which prevents a particular node from becoming the bottleneck of the network, when connected to too many neighbors. Evaluation results show the new protocol reduces network packet loss rate.

The Internet has scaled massively over the past 15 years to extend to billions of users. These users increasingly require extensive applications and capabilities from the Internet, such as Quality of Service (QoS) optimized paths between end hosts. When default Internet paths may not meet their requirements adequately, there is a need to facilitate the discovery of such QoS optimized paths. Fortunately, even though the route offered by the Internet may not work (to the required level of performance), often there exist alternate routes that do work. When the direct Internet path between two Internet hosts for instance is sub-optimal (according to specific user defined criterion), there is a possibility that the direct paths of both to a third host may not be suffering from the same problem owing to path disjointness. Overlay Networks facilitate the discovery of such composite alternate paths through third party hosts. To discover such alternate paths, overlay hosts regularly monitor both Internet path quality and choose better alternate paths via other hosts. Such measurements are costly and pose scalability problems for large overlay networks. This thesis asserts and shows that these overheads could be lowered substantially if the network layer path information between overlay hosts could be obtained, which facilitates selection of disjoint paths. This thesis further demonstrates that obtaining such network layer path information is very challenging. As opposed to the path monitoring which only requires cooperation of overlay hosts, disjoint path selection depends on the accuracy of information about the underlay, which is out of the domain of control of the overlay and so may contain inaccuracies. This thesis investigates how such information could be gleaned at different granularities for optimal tradeoffs between spatial and/or temporal methods for selection of alternate paths. The main contributions of this thesis are: (i) investigation of scalable techniques to facilitate alternate path computation using network layer path information; (ii) a review of the realistic performance gains achievable using such alternate paths; and (iii) investigation of techniques for revealing the presence of incorrect network layer path information, proposal of new techniques for its removal.

The Internet has scaled massively over the past 15 years to extend to billions of users. These users increasingly require extensive applications and capabilities from the Internet, such as Quality of Service (QoS) optimized paths between end hosts. When default Internet paths may not meet their requirements adequately, there is a need to facilitate the discovery of such QoS optimized paths. Fortunately, even though the route offered by the Internet may not work (to the required level of performance), often there exist alternate routes that do work. When the direct Internet path between two Internet hosts for instance is sub-optimal (according to specific user defined criterion), there is a possibility that the direct paths of both to a third host may not be suffering from the same problem owing to path disjointness. Overlay Networks facilitate the discovery of such composite alternate paths through third party hosts. To discover such alternate paths, overlay hosts regularly monitor both Internet path quality and choose better alternate paths via other hosts. Such measurements are costly and pose scalability problems for large overlay networks. This thesis asserts and shows that these overheads could be lowered substantially if the network layer path information between overlay hosts could be obtained, which facilitates selection of disjoint paths. This thesis further demonstrates that obtaining such network layer path information is very challenging. As opposed to the path monitoring which only requires cooperation of overlay hosts, disjoint path selection depends on the accuracy of information about the underlay, which is out of the domain of control of the overlay and so may contain inaccuracies. This thesis investigates how such information could be gleaned at different granularities for optimal tradeoffs between spatial and/or temporal methods for selection of alternate paths. The main contributions of this thesis are: (i) investigation of scalable techniques to facilitate alternate path computation using network layer path information; (ii) a review of the realistic performance gains achievable using such alternate paths; and (iii) investigation of techniques for revealing the presence of incorrect network layer path information, proposal of new techniques for its removal.

Zugl.: Ilmenau, Techn. University, Diss., 2007.

Zugl.: München, Techn. Univ., Diss., 2009

Zugl.: Darmstadt, Techn. Universiẗat, Diss., 2009.

Zugl.: Clausthal, Techn. Univ., Diss., 2009

Zugl.: Karlsruhe, Univ., Diss., 2008 / Hergestellt on demand

The aim of my thesis was to compare selectid allotment, Botanical composition of allotmnet and prortion were monitored. Assessment of medium water content in soil. For parametrs of burning was to find number of fertile and sterile culm. In literal research are summarized common data about biomass and particular grass used for energetic purposes. Detailed description of reed canary grass and its description, agrotechnology and harvest. It is also important to mention processing of biomass in to the shape briquet and pelets. In the last part of research is description of burning device for used biomass. The practice part description to optain sample particular lokalities and these results and compares them.

This report concerns the implementation of a simulation framework to evaluate an emerging peer-to-peer network topology scheme using 8-point hypercircles, entitled HyperCircle. This topology was proposed in order to alleviate some of the drawbacks of current P2P systems evolving in an uncontrolled manner, such as scalability issues, network overload and long search times. The framework is supposed to be used to evaluate the advantages of this new topology. The framework has been built on top of an existing simulator software solution, the selection of which was an important part of the development. Weighing different variables such as scalability and API usability, the selection fell on OverSim, an open-source discreet-event simulator based on OMNET++. After formalizing the protocol for easier implementation, as well as extending it for better performance, implementation followed using C++ with OverSim’s API and simulation library. Implemented as a module (alongside other stock modules providing their own protocols such as Chord and Kademlia), it can be used in OverSim to simulate a user-defined network using one of the simulation routine applications provided (or using a custom application written by the user). For the purposes of this thesis, the standard application KBRTestApp was used; an application sending test messages between randomly selected nodes, while adding and removing nodes at specific time intervals. The adding and removing of nodes can be configured with probability parameters. Tentative testing shows that this implementation of the HyperCircle protocol has a certain performance gain over the OverSim implementations of the Chord and Kademlia protocols, measurable in the time it takes a message to get from sender to recipient. Further testing is outside the scope of this thesis.