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Aktivní XML
Ignáth, Štefan ; Janeček, Jan (advisor) ; Nečaský, Martin (referee)
This work is concerned about the usage of so called active XML for the implementation of distributed algorithms. The active XML is introduced in the form of Web Services and the XML-RPC protocol. Both of these technologies are based on the exchange of XML-based messages. While the XML-RPC protocol is nowadays an unused and almost forgotten technology, the Web Services are getting more and more attention over the last few years. The communication of Web Services is based on the exchange of SOAP messages. The interface of these services is described by WSDL files. Besides the description of these already mentioned technologies, this thesis is concerned with possible modifications of these technologies in order to implement distributed algorithms. Since the requirements of distributed algorithms, as they are conceived by the academics, are diametrically different from the requirements of business applications, for which were the Web Services developed, great compromises are necessary. The practical part of this work points at possible solutions for the usage of Web Services in the distributed algorithm computing on an exemplary implementation. Another distributed algorithm is implemented with the usage of the XMLRPC protocol and the comparison of these implementations is done.
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Connector-based Performance Data Collection for Component Applications
Bulej, Lubomír ; Tůma, Petr (advisor) ; Janeček, Jan (referee) ; Murphy, John (referee)
In this work, we propose a generic approach to collection of performance data for hetero-geneous component-based applications with the aim to provide easier and less costly access to performance data needed for measurement and model-based performance analysis of component applications. The technical foundation for the approach is built on generic solutions to various aspects of performance data collection and is made of three parts. The first part provides a design of a generic measurement infrastructure which handles common performance measurement tasks and allows collecting arbitrary performance data in response to performance events. The second part proposes using architecture-based connectors for instrumentation of component applications and provides a design of a performance instrumentation connector element for use with the measurement infrastructure. The third part proposes integration of connectors into deployment process of component applications which enables deployment and transparent instrumentation of heterogeneous component-based applications.
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Flow control for the IEEE 802.11 access points
Turek, Lukáš ; Janeček, Jan (advisor) ; Peterka, Jiří (referee)
Wireless networks based on IEEE 802.11 standard (Wi-Fi) are nowadays often used as a last mile of Internet connection. However the standard was not designed with this use in mind, so this kind of deployment is rife with problems. One of these problems is high latency of network under high load caused by the absence of flow control. The present work explains why flow control algorithms implemented in operating systems cannot work in Wi-Fi networks e ectively and why even the 802.11e amendment yields no solution. Subsequently an algorithm designed specially for Wi-Fi networks, which divides bandwidth equally among clients and minimizes latency while not reducing network throughput, is proposed. The function of the algorithm is con firmed by simulation in OMNeT++ environment and the algorithm is then implemented in Linux and FreeBSD operating systems.
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Efektivní mechanismy XML komunikace
Rusnák, Pavol ; Janeček, Jan (advisor) ; Toman, Kamil (referee)
XML-based communication is e ective, because it is programmer-friendly and has great exibility. It is widely spread on variety of platforms. However, penetration of this technology has not yet reached embedded devices, because parsing of textual messages has usually large overhead and is demanding on resources. The goal of this work is to devise, implement and test a new method of parsing SOAP messages involving formal grammars and automata, thus allowing the use of web services to expand also to small devices, even on the ones without OS support. Our solution is called EXCUSA - acronym for "E ective XML Communication Using SOAP and Automata".
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Trust Management Systems in P2P Networks
Novotný, Miroslav ; Zavoral, Filip (advisor) ; Janeček, Jan (referee) ; Fujita, Satoshi (referee)
The architecture of certain class of services, such as distributed computing, distributed storages or content delivering networks shifts from the traditional client-server model to more scalable and robust peer to peer networks. Providing proper protection to such complex, open and anonymous systems is very complicated. Malicious peers can cooperate and develop sophisticated strategies to bypass existing security mechanisms. Recently, many trust management systems for P2P networks have been proposed. However, their effectiveness is usually tested only against simple malicious strategies. Moreover, a complex comparison of resistance of a particular method is missing. In this thesis, we (1) propose a new trust management system called BubbleTrust and (2) develop a simulation framework for testing trust management systems against various malicious strategies. Our simulation framework defines several criteria which determine the success of each malicious strategy in the network with a given system. We present results of four trust management systems that represent main contemporary approaches and BubbleTrust.
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Automated verification of software
Šerý, Ondřej ; Plášil, František (advisor) ; Janeček, Jan (referee) ; Ghezzi, Carlo (referee)
Despite the research e ort being invested into the eld of automated veri cation of software, its adoption in industry is still rather slow. Several reasons for this hesitation may be identi ed. The thesis focuses on the following two (i) dificulty of assessment of di erent tools, and (ii) difficulty of tools usage and integration in the development process. To facilitate tool assessment, we provide a comprehensive overview of code model checking techniques with evaluation based on a common set of criteria. In addition, we contribute by an industrial case study on applicability of the BLAST model checker. Since also proper education is necessary for the ability of tool assessment, we include our experience report on preparation of two master-level formal method courses. By incorporating an easy to use speci cation language into the BLAST model checker, the thesis contributes to facilitating tools usage. In addition, we introduce the concept of unit checking, a combination of unit testing and code model checking, which helps integration of code model checking in the software development process.
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Rozvrhování v distribuovaných systémech
Vyšohlíd, Jan ; Janeček, Jan (advisor) ; Yaghob, Jakub (referee)
The present work studies methods of scheduling in heterogeneous distributed systems. First there are introduced some theoretical basics which contain not only the scheduling theory itself but also the graph theory and the computational complexity theory. After that, compile-time scheduling methods and some well-known algorithms solving the problem are presented, followed by real-time scheduling basics and by classification of used methods. In the main part of the work there are proposed algorithms which respect additional restrictions. These algorithms are tested via the enclosed application and compared either to each other or to another algorithms which mostly don't respect additional restrictions. The mentioned application and the documentation for this application are a part of this work as well.
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Efektivní mechanismy XML komunikace
Rusnák, Pavol ; Toman, Kamil (referee) ; Janeček, Jan (advisor)
XML-based communication is e ective, because it is programmer-friendly and has great exibility. It is widely spread on variety of platforms. However, penetration of this technology has not yet reached embedded devices, because parsing of textual messages has usually large overhead and is demanding on resources. The goal of this work is to devise, implement and test a new method of parsing SOAP messages involving formal grammars and automata, thus allowing the use of web services to expand also to small devices, even on the ones without OS support. Our solution is called EXCUSA - acronym for "E ective XML Communication Using SOAP and Automata".
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Connector-based Performance Data Collection for Component Applications
Bulej, Lubomír ; Tůma, Petr (advisor) ; Janeček, Jan (referee) ; Murphy, John (referee)
In this work, we propose a generic approach to collection of performance data for hetero-geneous component-based applications with the aim to provide easier and less costly access to performance data needed for measurement and model-based performance analysis of component applications. The technical foundation for the approach is built on generic solutions to various aspects of performance data collection and is made of three parts. The first part provides a design of a generic measurement infrastructure which handles common performance measurement tasks and allows collecting arbitrary performance data in response to performance events. The second part proposes using architecture-based connectors for instrumentation of component applications and provides a design of a performance instrumentation connector element for use with the measurement infrastructure. The third part proposes integration of connectors into deployment process of component applications which enables deployment and transparent instrumentation of heterogeneous component-based applications.
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