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Evolutionary Design of Hash Functions
Kidoň, Marek ; Bidlo, Michal (referee) ; Dobai, Roland (advisor)
Hash tables are fast associative array implementations which became part of modern world of information technology and thanks to its simplicity became very popular among computer programmers. The choice of proper hash function is very important. Improperly selected hash function can result in poor hash table performance and its application. Currently there are many exceptional implementations of general hash functions. Such functions are not constrained to a concrete set of inputs, they perform on any input. On the other hand if we know the input domain we can design a specific hash function for desired application thus reaching better levels of performance compare to a general hash function. However hash function design is not trivial. There are no rules, standards, guides nor automated tools that would help us with such a task. In case of manual design the hash function author has to rely on his/her knowledge, experience, inventiveness and intuition. In case of such complicated tasks there is sometimes advantageous to choose a different path and use techniques such as evolution algorithms. Natural computing is an approach of certain problem solutions that are inspired by the process of species reproduction as defined by Charles Darwin. In this thesis we will design hash functions for the domain of IP addresses, that serve as an unique network device interface identifier in internet protocol networks. The chosen subset of natural computing is the genetic programming, a very specific technique that is an adequate approach to our problem thanks to its properties. Evolutionary designed hash functions offer good properties. They outperform state-of-the-art generic, human-created hash functions in terms of speed and collision resistance.
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IP Multimedia Subsystem
Bendíček, Martin ; Novotný, Vít (referee) ; Kovář, Petr (advisor)
This Master’s thesis deals with IMS architecture problems. This thesis describes its creation and progress, also structure of this architecture is mentioned. Text of this thesis describes function of the most important parts of the architecture, such as Proxy-CSCF, Interrogating-CSCF, Serving-CSCF and HSS. IMS architecture uses SIP protocol for establishment, maintenance and closing session and Diameter protocol for network management functions. That is why this thesis also describes characteristics of these two protocols. Next part of the thesis is focused on Open-source platform Open IMS Core and its installation. Open IMS Core platform was developed for testing IMS technologies within an internal project at the Fraunhofer Institute FOKUS in Berlin. Nowadays it is used by major part of vendors and providers for testing their products and services. As a main theme of this thesis, there was made a simple network, which consists of three users. This network is established on fundamentals of IMS and it was made in Open IMS Core. So in one chapter is outlined a process of its creation. There is described a process of adding a user list to database server HSS. In the next part there are mentioned some information about setup of virtual IMS terminal. Eventually there are shown some possibilities of how to catch traffic in the network. In this chapter there are also state diagrams, which describe a process of registration of IMS terminal and also a process of establishment, maintenance and closing session.
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Protocol IPv6 and its implementation scenarios
Rýzner, Zdeněk ; Krajsa, Ondřej (referee) ; Lambertová, Petra (advisor)
This thesis deals with IPv6 – the Internet layer protocol and its situation in today’s Internet. In theoretical part are described major changes, which the new protocol brings to networking area – especially addressing, headers format and autoconfiguration. Comparison of IPv6 and IPv4 is also included. Practical part covers connecting to IPv6-Internet with selected transition methods, analyses these methods and features its implementation in dependence on network environment.
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Optimisation of a Voice Transmission in Communication Networks
Novák, David ; Polívka, Michal (referee) ; Škorpil, Vladislav (advisor)
This master’s thesis deals abou the transmission of voice in communications networks. The theoretical part describes criteria for optimizing voice, such as quality of service, type of service, level of service, service type, and mean opinion score. Next I describe the Internet Protocol, comparing IPv4 and IPv6, VoIP, including security, protocols and parameters necessary for transmission. Other part is about neural networks. There are basically described the neural network, Hopfield neural network and Kohenen neural network. The research is based on a comparison of the network without ensuring the quality of service and with ensuring quality of service. Then, there are compared two types of switches. Classical switch-controlled sequentially, and switch controlled by neural networks. The overall simulation program is implemented in Opnet Modeler. The conclusion deals with the creation of laboratory tasks in this program to compare the different systems of ensuring quality of service.
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Router principles illustrating software for teaching support
Sobek, Jiří ; Vymazal, Michal (referee) ; Vychodil, Petr (advisor)
This bachelor thesis is mainly focused on the network functionality and its key component, the router. The main points of this work are an explanation of the network principles and router functions which are extended with information about routing protocols and its mutual separation. The practical part considers a realization of applets which should serve as a school software. In detail they explain the way of routing protocols work and its inner structure. Simultaneously consider the principles of two significant routing protocols such as Open Shortest Path First (OSPF) and Routing Information Protocol (RIP). All of the applets are finally loaded on the web page which helps to their visitors understand the complexity of routing and other infomation.
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Application explaining the principles of IP addressing
Bukovinský, Denis ; Jeřábek, Jan (referee) ; Langhammer, Lukáš (advisor)
This master's thesis presents the design and development of an application for teaching IP addressing in computer networks. The application includes a network simulator and an editor, allowing students to work with a predefined network topology, assign addresses to subnets, and customize the network as needed. It verifies the correctness of address assignments and detects address conflicts. The thesis covers theoretical background, implementation details, and testing of the application. The developed tool provides a valuable resource for students, facilitating their understanding and practice of IP addressing concepts in network education.
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Evolutionary Design of Hash Functions
Kidoň, Marek ; Bidlo, Michal (referee) ; Dobai, Roland (advisor)
Hash tables are fast associative array implementations which became part of modern world of information technology and thanks to its simplicity became very popular among computer programmers. The choice of proper hash function is very important. Improperly selected hash function can result in poor hash table performance and its application. Currently there are many exceptional implementations of general hash functions. Such functions are not constrained to a concrete set of inputs, they perform on any input. On the other hand if we know the input domain we can design a specific hash function for desired application thus reaching better levels of performance compare to a general hash function. However hash function design is not trivial. There are no rules, standards, guides nor automated tools that would help us with such a task. In case of manual design the hash function author has to rely on his/her knowledge, experience, inventiveness and intuition. In case of such complicated tasks there is sometimes advantageous to choose a different path and use techniques such as evolution algorithms. Natural computing is an approach of certain problem solutions that are inspired by the process of species reproduction as defined by Charles Darwin. In this thesis we will design hash functions for the domain of IP addresses, that serve as an unique network device interface identifier in internet protocol networks. The chosen subset of natural computing is the genetic programming, a very specific technique that is an adequate approach to our problem thanks to its properties. Evolutionary designed hash functions offer good properties. They outperform state-of-the-art generic, human-created hash functions in terms of speed and collision resistance.
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|
|
Router principles illustrating software for teaching support
Sobek, Jiří ; Vymazal, Michal (referee) ; Vychodil, Petr (advisor)
This bachelor thesis is mainly focused on the network functionality and its key component, the router. The main points of this work are an explanation of the network principles and router functions which are extended with information about routing protocols and its mutual separation. The practical part considers a realization of applets which should serve as a school software. In detail they explain the way of routing protocols work and its inner structure. Simultaneously consider the principles of two significant routing protocols such as Open Shortest Path First (OSPF) and Routing Information Protocol (RIP). All of the applets are finally loaded on the web page which helps to their visitors understand the complexity of routing and other infomation.
|
|
|
Protocol IPv6 and its implementation scenarios
Rýzner, Zdeněk ; Krajsa, Ondřej (referee) ; Lambertová, Petra (advisor)
This thesis deals with IPv6 – the Internet layer protocol and its situation in today’s Internet. In theoretical part are described major changes, which the new protocol brings to networking area – especially addressing, headers format and autoconfiguration. Comparison of IPv6 and IPv4 is also included. Practical part covers connecting to IPv6-Internet with selected transition methods, analyses these methods and features its implementation in dependence on network environment.
|
|
|
Optimisation of a Voice Transmission in Communication Networks
Novák, David ; Polívka, Michal (referee) ; Škorpil, Vladislav (advisor)
This master’s thesis deals abou the transmission of voice in communications networks. The theoretical part describes criteria for optimizing voice, such as quality of service, type of service, level of service, service type, and mean opinion score. Next I describe the Internet Protocol, comparing IPv4 and IPv6, VoIP, including security, protocols and parameters necessary for transmission. Other part is about neural networks. There are basically described the neural network, Hopfield neural network and Kohenen neural network. The research is based on a comparison of the network without ensuring the quality of service and with ensuring quality of service. Then, there are compared two types of switches. Classical switch-controlled sequentially, and switch controlled by neural networks. The overall simulation program is implemented in Opnet Modeler. The conclusion deals with the creation of laboratory tasks in this program to compare the different systems of ensuring quality of service.
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