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The Design of Minimal Bluetooth Stack
Gazda, Martin ; Zbořil, František (referee) ; Hanáček, Petr (advisor)
This master's thesis main aim is to design minimal Bluetooth stack for embedded applications running on an education platform FITkit. This paper contains a theoretical foundation for that work and implementation description. The main section includes Bluetooth protocol stack design and main opportunities which such a design raises.
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Rendering "Small" Plants in 3D Space
Řehánek, Jiří ; Přibyl, Jaroslav (referee) ; Herout, Adam (advisor)
This masters thesis deals with a real-time low vegetation rendering in 3D space. The low vegetation means grass and shrub. At first it looks on a implementation of vegetation in a 3D games that already exist and there investigate characteristics notable while playing and after that it comes to a evaluation of visual qualities. As next will follow design of solution of this problems and description of implementation. In final part will be summary of achieved product.
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Optimization of network flow monitoring
Žádník, Martin ; Lhotka,, Ladislav (referee) ; Matoušek, Radomil (referee) ; Sekanina, Lukáš (advisor)
The thesis deals with optimization of network flow monitoring. Flow-based network traffic processing, that is, processing packets based on some state information associated to the flows which the packets belong to, is a key enabler for a variety of network services and applications. The number of simultaneous flows increases with the growing number of new services and applications. It has become a challenge to keep a state per each flow in a network device processing high speed traffic. A flow table, a structure with flow states, must be stored in a memory hierarchy. The memory closest to the processing is known as a flow cache. Flow cache management plays an important role in terms of its effective utilization, which affects the performance of the whole system. This thesis focuses on an automated design of cache replacement policy optimized to a deployment on particular networks. A genetic algorithm is proposed to automate this process. The genetic algorithm generates and evaluates evolved replacement policies by a simulation on obtained traffic traces. The proposed algorithm is evaluated by designing replacement policies for two variations of the cache management problem. The first variation is an evolution of the replacement policy with an overall low number of state evictions from the flow cache. The second variation represents an evolution of the replacement policy with a low number of evictions belonging to large flows only. Optimized replacement policies for both variations are found while experimenting with various encoding of the replacement policy and genetic operators. The newly evolved replacement policies achieve better results than other tested policies. The evolved replacement policy lowers the overall amount of evictions by ten percent in comparison with the best compared policy. The evolved replacement policy focusing on large flows lowers the amount of their evictions two times. Moreover, no eviction occurs for most of the large flows (over 90%). The evolved replacement policy offers better resilience against flooding the flow cache with large amount of short flows which are typical side effects of scanning or distributed denial of service activities. An extension of the replacement policy is also proposed. The extension complements the replacement policy with an additional information extracted from packet headers. The results show further decrease in the number of evictions when the extension is used.
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Garbage Collector for PNtalk Objects
Mišák, Ján ; Janoušek, Vladimír (referee) ; Kočí, Radek (advisor)
This thesis deals with the designing of a garbage collector for the PNtalk virtual machine. It describes and rates the approaches and algorithms for an automatic memory management. Four algorithm families ale presented: mark-sweep, mark-compact, copying algorithms and reference counting. At first it describes sequential forms, that pauses running of the main program (mutator), then it describes parallel and concurent forms, that do not pauses the mutator. The thesis also presents generational model of garbage collecting. The following sections briefly introduces object orientated Petri nets. The result of this thesis is the design of the generational garbage collector for the PNtalk virtual machine.
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Advanced speech coding methods using digital signal processor
Zajíček, Marek ; Sysel, Petr (referee) ; Smékal, Zdeněk (advisor)
This master thesis describes the practical usage of AMR-WB (Adaptive Multi Rate - Wide Band) codec and its implementation on a digital signal processor which is integrated in functional voice communication system Siemens HiPath 4000. The first part is focused on the complete codec description, especially on an encoder and decoder. The second part partly describes signal processors and then is followed by the practical part of the implementation which is solved from the preliminary activities up to the optimalization of the final functional solution.
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Memory Management in Linux
Tuček, Jaroslav ; Kočí, Radek (referee) ; Vojnar, Tomáš (advisor)
This work describes the memory manager subsystem of the linux kernel. The first part gives a brief account of operating systems architecture and memory management theory - of virtual memory management, page tables, page replacement algorithms and kernel allocators in particular. The second part discusses the actual implementation of these principles in a modern kernel - in linux. Finally, a series of tests stressing the memory subsystem is conducted to determine the memory manager's real behaviour. Limitations of the current linux kernel memory management and some of their proposed solutions are also discussed.
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Optimization of network flow monitoring
Žádník, Martin ; Lhotka,, Ladislav (referee) ; Matoušek, Radomil (referee) ; Sekanina, Lukáš (advisor)
The thesis deals with optimization of network flow monitoring. Flow-based network traffic processing, that is, processing packets based on some state information associated to the flows which the packets belong to, is a key enabler for a variety of network services and applications. The number of simultaneous flows increases with the growing number of new services and applications. It has become a challenge to keep a state per each flow in a network device processing high speed traffic. A flow table, a structure with flow states, must be stored in a memory hierarchy. The memory closest to the processing is known as a flow cache. Flow cache management plays an important role in terms of its effective utilization, which affects the performance of the whole system. This thesis focuses on an automated design of cache replacement policy optimized to a deployment on particular networks. A genetic algorithm is proposed to automate this process. The genetic algorithm generates and evaluates evolved replacement policies by a simulation on obtained traffic traces. The proposed algorithm is evaluated by designing replacement policies for two variations of the cache management problem. The first variation is an evolution of the replacement policy with an overall low number of state evictions from the flow cache. The second variation represents an evolution of the replacement policy with a low number of evictions belonging to large flows only. Optimized replacement policies for both variations are found while experimenting with various encoding of the replacement policy and genetic operators. The newly evolved replacement policies achieve better results than other tested policies. The evolved replacement policy lowers the overall amount of evictions by ten percent in comparison with the best compared policy. The evolved replacement policy focusing on large flows lowers the amount of their evictions two times. Moreover, no eviction occurs for most of the large flows (over 90%). The evolved replacement policy offers better resilience against flooding the flow cache with large amount of short flows which are typical side effects of scanning or distributed denial of service activities. An extension of the replacement policy is also proposed. The extension complements the replacement policy with an additional information extracted from packet headers. The results show further decrease in the number of evictions when the extension is used.
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Garbage Collector for PNtalk Objects
Mišák, Ján ; Janoušek, Vladimír (referee) ; Kočí, Radek (advisor)
This thesis deals with the designing of a garbage collector for the PNtalk virtual machine. It describes and rates the approaches and algorithms for an automatic memory management. Four algorithm families ale presented: mark-sweep, mark-compact, copying algorithms and reference counting. At first it describes sequential forms, that pauses running of the main program (mutator), then it describes parallel and concurent forms, that do not pauses the mutator. The thesis also presents generational model of garbage collecting. The following sections briefly introduces object orientated Petri nets. The result of this thesis is the design of the generational garbage collector for the PNtalk virtual machine.
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Memory Management in Linux
Tuček, Jaroslav ; Kočí, Radek (referee) ; Vojnar, Tomáš (advisor)
This work describes the memory manager subsystem of the linux kernel. The first part gives a brief account of operating systems architecture and memory management theory - of virtual memory management, page tables, page replacement algorithms and kernel allocators in particular. The second part discusses the actual implementation of these principles in a modern kernel - in linux. Finally, a series of tests stressing the memory subsystem is conducted to determine the memory manager's real behaviour. Limitations of the current linux kernel memory management and some of their proposed solutions are also discussed.
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The Design of Minimal Bluetooth Stack
Gazda, Martin ; Zbořil, František (referee) ; Hanáček, Petr (advisor)
This master's thesis main aim is to design minimal Bluetooth stack for embedded applications running on an education platform FITkit. This paper contains a theoretical foundation for that work and implementation description. The main section includes Bluetooth protocol stack design and main opportunities which such a design raises.
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