Software bugs are expensive. Recent estimates by the US National Institute of Standards and Technology claim that the cost of software bugs to the US economy alone is approximately 60 billion USD annually. As society becomes increasingly software-dependent, bugs also reduce our productivity and threaten our safety and security. Decreasing these direct and indirect costs represents a significant research challenge as well as an opportunity for businesses. Automatic software bug-finding and verification tools have a potential to completely revolutionize the software engineering industry by improving reliability and decreasing development costs. Since software analysis is in general undecidable, automatic tools have to use various abstractions to make the analysis computationally tractable. Abstraction is a double-edged sword: coarse abstractions, in general, yield easier verification, but also less precise results. This thesis focuses on exploiting the structure of software for abstracting away irrelevant behavior. Programmers tend to organize code into objects and functions, which effectively represent natural abstraction boundaries. Humans use such structural abstractions to simplify their mental models of software and for constructing informal explanations of why a piece of code should work. A natural question to ask is: How can automatic bug-finding tools exploit the same natural abstractions? This thesis offers possible answers. More specifically, I present three novel ways to exploit structure at three different steps of the software analysis process. First, I show how symbolic execution can preserve the data-flow dependencies of the original code while constructing compact symbolic representations of programs. Second, I propose structural abstraction, which exploits the structure preserved by the symbolic execution. Structural abstraction solves a long-standing open problem --- scalable interprocedural path- and context-sensitive program analysis. Finally, I present an automatic tuning approach that exploits the fine-grained structural properties of software (namely, data- and control-dependency) for faster property checking. This novel approach resulted in a 500-fold speedup over the best previous techniques. Automatic tuning not only redefined the limits of automatic software analysis tools, but also has already found its way into other domains (like model checking), demonstrating the generality and applicability of this idea.

This paper is intended to serve as a supporting document for the exhibition This Site Is Under Construction that was held at the University of Waterloo Art Gallery, University of Waterloo, April 17th – May 14th, 2010. The work explores the ways in which we constitute and mediate our specific place in a space that is constantly changing. It is concerned with notions surrounding how we make and perceive images now in our computerized visual culture and the ways in which we can mark a subjective painting aesthetic and visual vocabulary. The painting installation, “This Site Is Under Construction”, investigates the effects of new media and digitization on experiential perception, and the nature of making and re-configuring images. The title alludes not only to the on-line, virtual space of the computer, but also to the physical spaces of building and urban development sites. The subjects for the paintings are spaces in flux – specific locales of construction and building sites that are in-between states of development – placing emphasis on the mechanized devices that fabricate the new structures. The paintings themselves reveal seemingly spontaneous and optically warped immersive spaces; alternative architectural environments which subvert interpretations of two-dimensional and three-dimensional forms of visual presentation and recognition. The work aims to contrast outward appearance and illusionistic staging as it relates to both the picture and its support.

Nikolaïs a prolongé la pensée de Laban et l'a enrichie en l'expérimentant sur les corps-mêmes des danseurs de sa compagnie. son approche s'est développée dans un va-et-vient constant entre les 'principles' et l'expérience sensible du corps dansant. les éléments de langage chorégraphique (qualités de 'motion', 'shape'...) et les outils pédagogiques de nikolaïs (décentrement, 'gestalt' ou totalité reconnaissable, triade technique-improvisation-composition...) se sont élaborés sans être soumis à un savoir théorique extérieur. Cet enseignement consiste à munir le corps et l'esprit d'un savoir et d'une conscience immédiate des facteurs entrant en jeu dans le mouvement dansé. L'étude tendra à affirmer que là où il y a pédagogie, il y a théorie. la 'theory' est chez Nikolaïs un moment d'investigation à travers l'improvisation où concept, chorégraphie et performances sont instantanés. l'improvisation, un des éléments-clés de la modernité en danse, semble donc représenter le processus privilégié où pratique et théorie se confondent ou se vérifient l'une l'autre. Par ailleurs, sera aussi questionnée la prétendue "universalité" des outils et éléments de syntaxe de Nikolaïs, par l'analyse du contexte particulier des années 1950 (historique, socio-politique, artistique et technologique) et l'idéologie très liée à la personnalité de son créateur et à l'engouement qu'il a suscité. On se propose donc de déconstruire le modèle en empruntant une troisième voie au-delà de l'héritage fidèlement entretenu ou rejeté pour tenter, en contrant la présence diffuse de cet enseignement en France, une réhabilitation et une analyse qui questionneront la pertinence et les enjeux de cette pensée aujourd'hui.

Ekspresija -raiškumas , išraiškingumas tai atspindi diplominio darbo pavadinimą. Kiekvieno teptuko potėpis įšaukia ekspromtu išsiliejančius jausmus. Darbas susideda iš dviejų dalių: teorinio aprašo ir praktinio kūrybinio darbo. Teorinėje dalyje apžvelgiama darbo eigą, kūrybinio darbo idėjos paieška , priemonės ir atlikimo techniką, dailės terminai, abstrakcionizmas, abstrakcijos. Įsigilinama į tapybos esme. Tapomos abstrakcijos lyginamos su pirmojo abstrakcionizmo pradininko Vasilijaus Kandinskio darbais. Praktinį kūrybinis darbas sudaromas trijų darbų ciklai (95 cm x 120 cm), atliekama ant kartono aliejiniais ir emaliniais purškiamais dažais. Perteikiamas jausmingumas , tryškintis energija atskleidžiamos emocijas spalvų ritme, judesio aktyvume. / Expression, distinctiveness and expressiveness reflect in the title of the diploma work. Every single touch of a brush calls out senses which overflow off-hand. The paper consists of two parts: theoretical description and practical creative work.In the theoretical part are given the description of the work itself, the search of the idea of the creative work, means and implementation of the work, scientific art terms, abstractions. The theoretical part also inquires into the heart of the matter.The painted abstarctions are compared with the works of Vasilij Kandinskij, the initiator of abstractionizm. Practical work consists of three works (95 120cm) which are performed on pasteboard with oil-paint and enamel. Expression, sensitiveness, energy are expressed through colours and motions.

Darbais kuriame savo istoriją, tarsi stebuklinį mitą, kuris tampa savotišku veidrodžiu, rodančiu regimus ir neregimus mūsų sielos pavidalus. Gintauto Nauronio tapyba taip pat jo gyvenimo metraštis, abstraktūs vaizdai, žmogaus pažvelgimas į save, į savo vidinį pasaulį, charakterio, temperamento savybes, egzistenciją. Aliejinės tapybos darbų kolekcija "Abstrakti vizija"- tai sielos harmonija, kurios nereikia filosofiškai paaiškinti – užtenka išgyventi, pajusti, nuspėti. Dailininko prigimtis, įvaldyta tapybinė technika, sugebanti įkvėpti gyvybę drobei. Įvairiausių spalvų ir atspalvių deriniai, kompozicijose panaudota linija, tapybos ciklui suteikia ypatingo skambesio. Darbuose dvelkianti ramybė, nuoširdumas, tyrumas, fantazija, jautrumas, optimizmas, ryžtas, geros, šviesios mintys užpildo naujais pojūčiais kiekvieno žiūrovo sielą ir gerą nuotaiką… Dinamiškas modernistinis tapymo būdas, kurio pagrindas - tikėjimas, esą vidines pajautas, intuicijas, jausmus, potyrius bei būsenas betarpiškai perteikia spontaniška estetinio impulso raiška, suardanti nusistovėjusį pasaulį, jo vaizdą ir deformuojanti jo pavidalus. Magistro darbas susideda iš dviejų dalių: teorinio aprašo ir praktinio kūrybinio darbo. Teorinėje dalyje apžvelgiama kolekcijos koncepcija, idėjos ir temos paieška, darbe nagrinėjama problema, darbo tikslo bei uždavinių konkretizavimas, apžvelgiamos abstrakcionizmo, ekspresionizmo, fovizmo temos, spalvos reikšmė mene, kompozicijos... [toliau žr. visą tekstą] / By works we create own history, sort of magic myth, which becomes a peculiar mirror showing visible and invisible our shapes of soul. The painting of Gintautas Nauronis and also his chronicle of life, abstract images, and human’s look into himself, his inner world, character, temperament’s features, existence. The creative collection of oily paintings Abstract Vision – it is soul‘s harmony, which is needn‘t to explain philosofically – it is enough to outlive, feel, foresee. The nature of painter, acquired pictorial technique, which is able to animate for a linen. The combinations of various colours and tones, a line used in the composition give a special sound for cycle of painting. The calm, warm, energy, breath, optimism, strength, sensibility and even love whiffling in the paintings, fill every spectator‘s soul and moode by new feelings... Dynamic modernistic method of painting, whose principle - belief that sensations, intuitions, feelings, experiences and states are proximately conveyd by spontaneous aesthetical expression of impulse, which destroys a well-established view of life and deforms its shapes. Dissertation consists of to parts: theoretical schedule and practical creative work. In the theoretical part it is overlook ideas and search of theme, the significance of abstractionism, expressionism, fovism and colour in the art, conception of composition, it is also provided theoretical material of Dr. Robert Belton What is Art?, What is... [to full text]

Miestas naktį“ tai trijų darbų kolekcija. Kolekcijoje dominuoja bordo (ochros) spalvų koloritas, vertikalių ir horizontalių ritmas. Atlikimo technika - pastozinė tapyba. Diplominis darbas susideda iš dviejų dalių: teorinio aprašo ir praktinio kūrybinio darbo. Teorinėje dalyje apžvelgiama idėjos formavimasis, temos nagrinėjimas istoriniame kontekste, abstraktusis menas, veiksmo tapyba, analogų paieška ir darbų analizė, pedagoginis pritaikomumas. Taip pat pateikiama kūrybinio darbo eiga, technika, priemonės. Praktinį darbą sudaro trijų darbų kolekcija, pavadinimu ,,Miestas naktį.“ ( akrilas, drobė 110 x 85). Darbai yra abstraktūs, būdingas ekspresyvumas, emocinė įtampa, kontrastingos spalvos, konstruktyvumas. / “The City at Night” is a collection of three paintings. The burgundy (ochre) colors and the rhythm of vertical and horizontal lines prevail in the collection. The technique applied is impasto. The final paper is comprised of the following two parts: a theoretical analysis and a creative practical part. The theoretical part is focused on the formation of an idea and an analysis of the topic in the historical context, abstract art, action painting, analogue search, analysis of works and possibilities of educational application. Also, the procedure of the creative task as well as the applied technique and tools are presented. The practical part of the paper consists of a collection of three paintings called “The City at Night” (acrylic paint, canvas size 110 x 85). The paintings are abstract with inherent expressiveness, emotional tension, contrasting colors and constructivism.

The state-based approach plays an important role in modeling and control of Discrete-Event Systems (DES). Based on previous work, state feedback control of DES with nonblocking is thoroughly investigated; a general construction method for memory and the corresponding predicate is also specified. Two examples are provided in illustration. Also presented is state-based control of DES with observational abstraction. Based on the existing idea of quasi-congruence, quasi-observer, as a kind of observational abstraction, is developed; its advantages and limitations are discussed by means of simple examples. Imposing an observational partition on the state set also leads to observational abstraction. On this basis, the state-feedback controller design is introduced; in particular, the notion of high and low modeling levels for DES is proposed, based on which reachability and controllability are further discussed and compared. Finally, two simple applications are provided to show the advantage of observational partition in DES analysis and control.

The state-based approach plays an important role in modeling and control of Discrete-Event Systems (DES). Based on previous work, state feedback control of DES with nonblocking is thoroughly investigated; a general construction method for memory and the corresponding predicate is also specified. Two examples are provided in illustration. Also presented is state-based control of DES with observational abstraction. Based on the existing idea of quasi-congruence, quasi-observer, as a kind of observational abstraction, is developed; its advantages and limitations are discussed by means of simple examples. Imposing an observational partition on the state set also leads to observational abstraction. On this basis, the state-feedback controller design is introduced; in particular, the notion of high and low modeling levels for DES is proposed, based on which reachability and controllability are further discussed and compared. Finally, two simple applications are provided to show the advantage of observational partition in DES analysis and control.

Baigiamajame darbe suteikti įspūdį, kuris išreiškiamas per spalvas, dėmes, šešėlius ir judesį. Baigiamojo darbo atlikimo technika yra gana nauja, nes tokio tipo darbų nėra. Ieškant pavyzdžių, jų nebuvo rasta. Technika buvo atrasta remiantis bandomųjų darbų eskizais. Pasirinkus pastozinę tapybą, galima nutapyti įvairias temas išreiškiant jas abstrakcijomis, judesiu, spalvomis. Abstrakcija prasideda nuo tikrovės, kuri apkarpoma atsikratant pertekliaus, ir galiausiai atsiskleidžia vertinga, dažnai netikėta esmė, sukuriamas minimalus žodynas, perteikiantis kuo daugiau pojūčių ir jausmų. / To create an impression witch is expressed by colors, splashes, shadows and movements. The technique of my bachelor is quite new, because there aren’t such types of works. In searching such works it was not found. This technique was found with reference to experimental sketch of work. In selecting the postoso action painting is possible to paint various themes expressing it with abstractions, movements, colors. The abstraction starts from reality which get a rid of abundance and ultimately dehisce valuable, frequently unexpected essentiality. Is creating a minimal vocabulary witch convey more sensations and sensibilities.

Mathematics is defined as an abstract way of thinking. Abstraction ranks among the least accessible mental activities. In an educational context the encounter with mathematical abstraction is the crucial step of the transition from informal school mathematics to the formalism of university mathematics. This transition is characterised by cognitive tensions. This study aimed at the identification and exploration of the tensions in the novice mathematician's encounter with mathematical abstraction. For this purpose twenty first-year mathematics undergraduates were observed in their weekly tutorials in four Oxford Colleges during Michaelmas and Hilary Term of Year 1. Tutorials were tape-recorded and fieldnotes kept during observation. The students were also interviewed at the end of each term of observation. The recordings of the observed tutorials and the interviews were transcribed and submitted to an analytical process of filtering out episodes that illuminate the novices' cognition. An analytical framework consisting of cognitive and sociocultural theories on learning was applied on sets of episodes within the mathematical areas of Foundational Analysis, Calculus, Linear Algebra and Group Theory. This topical analysis was followed by a cross-topical synthesis of themes that were found to characterise the novices' cognition. The novices' encounter with mathematical abstraction was described as a personal meaning-construction process and as an enculturation process: the new culture is Advanced Mathematics introduced by an expert, the tutor. The novices' interaction with the new concept definitions was obstructed by their unstable previous knowledge. Concept image construction was described as a construction of meaningful metaphors and an exploration of the 'raison-d'-être' of the new concepts and the new reasoning and was characterised by the tension between the Informal/Intuitive/Verbal and the Formal/Abstract/Symbolic — which was discussed in terms of semantics and reasoning. The novices were in difficulty with the mechanics of formal mathematical reasoning as well as with applying these mechanics in a contextualised manner. This decontextualised behaviour was linked to the fragility of their knowledge with regard to the nature of rigour in formal mathematics.