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Reflectively extensible programming languages are programming languages, whose syntax (and/or semantics) can be extended without any direct compiler modifications. Specialized syntax analysis methods are needed to parse such languages. In this dissertation a new parsing method for parsing such languages is presented: Scannerless Earley virtual machine (SEVM). This method supports dynamically changing grammars with local (temporary) extensions, is scannerless, recognises all context-free grammars and allows language definition via grammar composition. SEVM is a virtual-machine based parser: it uses instruction sequences to represent grammars internally. These instructions are then interpreted (or executed using a just-in-time compiler) to drive overall parsing process. Much attention is given to SEVM optimisations to ensure acceptable parsing performance. In the final part of this thesis, the parsing performance of SEVM implementation is compared to other parser implementations that are used in practise. We found that SEVM offers acceptable parsing performance for practical application.

Reflectively extensible programming languages are programming languages, whose syntax (and/or semantics) can be extended without any direct compiler modifications. Specialized syntax analysis methods are needed to parse such languages. In this dissertation a new parsing method for parsing such languages is presented: Scannerless Earley virtual machine (SEVM). This method supports dynamically changing grammars with local (temporary) extensions, is scannerless, recognises all context-free grammars and allows language definition via grammar composition. SEVM is a virtual-machine based parser: it uses instruction sequences to represent grammars internally. These instructions are then interpreted (or executed using a just-in-time compiler) to drive overall parsing process. Much attention is given to SEVM optimisations to ensure acceptable parsing performance. In the final part of this thesis, the parsing performance of SEVM implementation is compared to other parser implementations that are used in practise. We found that SEVM offers acceptable parsing performance for practical application.

Saugos problemos virtualizuotose aplinkose tampa vis aktualesnės, todėl darbe nagrinėjama piktavališkos programinės įrangos virtualių mašinų aplinkoje aptikimo problematika. Darbe pateikiama: 1)piktavališkos programinės įrangos veikiančios virtualizuotose aplinkose analizė 2)metodikos, piktavališkos programinės įrangos virtualių mašinų aplinkoje aptikimui, sudarymas 3)piktavališkos programinės įrangos virtualioje mašinoje aptikimo, panaudojant sudaryta metodiką, eksperimento rezultatai ir jų priklausomybė nuo virtualios mašinos darbinės atminties dydžio. In the context of virtual environment, The Security problems are highly important. The work presents analysis of malware types and it‘s presence in virtualized environments. Work also presents some results of experiments that have been carried out within the real virtual machine environment through modeling aiming to identify dependencies between the malware type, called Rootkits, detection time and the virtual machine memory size. Rootkits exploit kernel vulnerabilities and gain privileges (popularity) within any system, virtual or not. The basic result of the work is as follows: 1) the malware detection methodology for the virtual environment when the memory size of a virtual machine is changing; 2) dependences between the virtual machine memory size and Rootkit detection time.

Saugos problemos virtualizuotose aplinkose tampa vis aktualesnės, todėl darbe nagrinėjama piktavališkos programinės įrangos virtualių mašinų aplinkoje aptikimo problematika. Darbe pateikiama: 1)piktavališkos programinės įrangos veikiančios virtualizuotose aplinkose analizė 2)metodikos, piktavališkos programinės įrangos virtualių mašinų aplinkoje aptikimui, sudarymas 3)piktavališkos programinės įrangos virtualioje mašinoje aptikimo, panaudojant sudaryta metodiką, eksperimento rezultatai ir jų priklausomybė nuo virtualios mašinos darbinės atminties dydžio., In the context of virtual environment, The Security problems are highly important. The work presents analysis of malware types and it‘s presence in virtualized environments. Work also presents some results of experiments that have been carried out within the real virtual machine environment through modeling aiming to identify dependencies between the malware type, called Rootkits, detection time and the virtual machine memory size. Rootkits exploit kernel vulnerabilities and gain privileges (popularity) within any system, virtual or not. The basic result of the work is as follows: 1) the malware detection methodology for the virtual environment when the memory size of a virtual machine is changing; 2) dependences between the virtual machine memory size and Rootkit detection time.