Stream Processing using Grammars and Regular Expressions

In this dissertation we study regular expression based parsing and the use of grammatical specifications for the synthesis of fast, streaming string-processing programs. In the first part we develop two linear-time algorithms for regular expression based parsing with Perl-style greedy disambiguation. The first algorithm operates in two passes in a semi-streaming fashion, using a constant amount of working memory and an auxiliary tape storage which is written in the first pass and consumed by the second. The second algorithm is a single-pass and optimally streaming algorithm which outputs as much of the parse tree as is semantically possible based on the input prefix read so far, and resorts to buffering as many symbols as is required to resolve the next choice. Optimality is obtained by performing a PSPACE-complete pre-analysis on the regular expression. In the second part we present Kleenex, a language for expressing high-performance streaming string processing programs as regular grammars with embedded semantic actions, and its compilation to streaming string transducers with worst-case linear-time performance. Its underlying theory is based on transducer decomposition into oracle and action machines, and a finite-state specialization of the streaming parsing algorithm presented in the first part. In the second part we also develop a new linear-time streaming parsing algorithm for parsing expression grammars (PEG) which generalizes the regular grammars of Kleenex. The algorithm is based on a bottom-up tabulation algorithm reformulated using least fixed points and evaluated using an instance of the chaotic iteration scheme by Cousot and Cousot

Protecting Systems From Exploits Using Language-Theoretic Security

Any computer program processing input from the user or network must validate the input. Input-handling vulnerabilities occur in programs when the software component responsible for filtering malicious input---the parser---does not perform validation adequately. Consequently, parsers are among the most targeted components since they defend the rest of the program from malicious input. This thesis adopts the Language-Theoretic Security (LangSec) principle to understand what tools and research are needed to prevent exploits that target parsers. LangSec proposes specifying the syntactic structure of the input format as a formal grammar. We then build a recognizer for this formal grammar to validate any input before the rest of the program acts on it. To ensure that these recognizers represent the data format, programmers often rely on parser generators or parser combinators tools to build the parsers. This thesis propels several sub-fields in LangSec by proposing new techniques to find bugs in implementations, novel categorizations of vulnerabilities, and new parsing algorithms and tools to handle practical data formats. To this end, this thesis comprises five parts that tackle various tenets of LangSec. First, I categorize various input-handling vulnerabilities and exploits using two frameworks. First, I use the mismorphisms framework to reason about vulnerabilities. This framework helps us reason about the root causes leading to various vulnerabilities. Next, we built a categorization framework using various LangSec anti-patterns, such as parser differentials and insufficient input validation. Finally, we built a catalog of more than 30 popular vulnerabilities to demonstrate the categorization frameworks. Second, I built parsers for various Internet of Things and power grid network protocols and the iccMAX file format using parser combinator libraries. The parsers I built for power grid protocols were deployed and tested on power grid substation networks as an intrusion detection tool. The parser I built for the iccMAX file format led to several corrections and modifications to the iccMAX specifications and reference implementations. Third, I present SPARTA, a novel tool I built that generates Rust code that type checks Portable Data Format (PDF) files. The type checker I helped build strictly enforces the constraints in the PDF specification to find deviations. Our checker has contributed to at least four significant clarifications and corrections to the PDF 2.0 specification and various open-source PDF tools. In addition to our checker, we also built a practical tool, PDFFixer, to dynamically patch type errors in PDF files. Fourth, I present ParseSmith, a tool to build verified parsers for real-world data formats. Most parsing tools available for data formats are insufficient to handle practical formats or have not been verified for their correctness. I built a verified parsing tool in Dafny that builds on ideas from attribute grammars, data-dependent grammars, and parsing expression grammars to tackle various constructs commonly seen in network formats. I prove that our parsers run in linear time and always terminate for well-formed grammars. Finally, I provide the earliest systematic comparison of various data description languages (DDLs) and their parser generation tools. DDLs are used to describe and parse commonly used data formats, such as image formats. Next, I conducted an expert elicitation qualitative study to derive various metrics that I use to compare the DDLs. I also systematically compare these DDLs based on sample data descriptions available with the DDLs---checking for correctness and resilience

A World for All and None: De Stijl, Modernism, and the Decorative Arts

In October 1917, the first issue of the journal De Stijl was printed in the Netherlands under the editorial leadership of Theo van Doesburg. The publication became a nexus around which a core group of progressive artists, architects, and designers were brought together. They all shared a similar goal: to be a platform through which a new aesthetic would be declared, one that would diagnose and resolve the social, cultural, and metaphysical conditions that had led to the First World War. The group’s vision was totalizing, meant to encompass all forms of art, from armchairs to architecture. This dissertation explores the position of the decorative arts within De Stijl’s utopian project. The decorative arts were the bellwether of many of the principal social, cultural, and political problems that modernity brought to the fore. As a result, the polemics that emerged from the decorative arts profoundly informed the development of De Stijl’s artistic praxis and theoretical framework during the formative years of the group. By acknowledging the origins of many of De Stijl’s intellectual and aesthetic positions within the decorative arts, this dissertation aims to present a renewed perspective on the group’s formal projects in interior design, stained glass, and furniture. By rooting the work of these artists within the instrumental role of the decorative arts, this dissertation gives needed attention to these essential, yet undertheorized aspects of De Stijl’s utopian project to provide new insights into one of the most prominent artistic movements of the interwar period. In doing so, it endeavors to call for a broader reassessment of the intrinsic role the decorative arts played in the emergence of modernism broadly, and the practice of the European avant-garde specifically, in the years following World War I

Feminist Futures of Spatial Practice: Materialisms, activisms, dialogues, pedagogies, projections

Architecture and the arts have long been on the forefront of socio-spatial struggles, in which equality, access, representation and expression are at stake in our cities, communities and everyday lives. Feminist spatial practices contribute substantially to new forms of activism, expanding dialogues, engaging materialisms, transforming pedagogies, and projecting alternatives. Feminist Futures of Spatial Practice traces practical tools and theoretical dimensions, as well as temporalities, emergence, histories, events, durations – and futures – of feminist practices. Authors include international practitioners, researchers, and educators, from architecture, the arts, art history, curating, cultural heritage studies, environmental sciences, futures studies, film, visual communication, design and design theory, queer, intersectional and gender studies, political sciences, sociology, and urban planning. Established as well as emerging voices write critically from within their institutions, professions, and their activist, political and personal practices. Feminist Futures of Spatial Practice deepens and broadens how we can understand and engage with different genders, bodies and peoples, diverse voices and forms of expression, alternative norms and ways of living together

Non-monogamies and the space of discourse theorizing the intersections of non/monogamy and intimate privilege in the public sphere

This dissertation uses genealogical discourse analysis to unpack recent Western conceptions of monogamy and non-monogamy in the public sphere. Beginning from the premise that discourses surrounding monogamy and non-monogamy (taken together as a system of non/monogamy) have come into particular prominence in recent years, this dissertation deploys a thread of queer theory focused on the study of broader conceptions of "intimacy" to explore the ramifications of such a prominence in the public sphere. More specifically, drawing on theorizations of spatiality (Temporary Autonomous Zones, Mapping/Reterritorialization, Heterotopia) and the concept of "privilege", I formulate the theoretical lens of "intimate privilege" to explore how non/monogamy is distributed throughout, takes up, and creates forms of intimate space. In exploding the overly-simple notion that monogamous sexuality is societally privileged, while non-monogamies are marginalized, I show how while there is a societal meta-narrative that centres monogamy, it is really the intersectionality of non/monogamy with other forms of privilege/oppression that truly locates a subject practicing (or connected to) non-monogamous intimacy as having intimate privilege, defined as the emergent state in which one's intimacies hold societal privilege. Engaging in theoretical and discursive analyses of the contemporary public sphere presences of three major forms of non-monogamy (adultery, polygamy and polyamory) through texts such as journalistic articles, policy documents, self-help literature, television programs and Internet sites, I continue the academic discussion surrounding non-monogamies that is just beginning to come into its own in the fields of social science and humanities, as well as to complicate less-nuanced discourses on non/monogamy that are circulating more broadly in the public sphere

The Big Five:Addressing Recurrent Multimodal Learning Data Challenges

The analysis of multimodal data in learning is a growing field of research, which has led to the development of different analytics solutions. However, there is no standardised approach to handle multimodal data. In this paper, we describe and outline a solution for five recurrent challenges in the analysis of multimodal data: the data collection, storing, annotation, processing and exploitation. For each of these challenges, we envision possible solutions. The prototypes for some of the proposed solutions will be discussed during the Multimodal Challenge of the fourth Learning Analytics & Knowledge Hackathon, a two-day hands-on workshop in which the authors will open up the prototypes for trials, validation and feedback

Multimodal Challenge: Analytics Beyond User-computer Interaction Data

This contribution describes one the challenges explored in the Fourth LAK Hackathon. This challenge aims at shifting the focus from learning situations which can be easily traced through user-computer interactions data and concentrate more on user-world interactions events, typical of co-located and practice-based learning experiences. This mission, pursued by the multimodal learning analytics (MMLA) community, seeks to bridge the gap between digital and physical learning spaces. The “multimodal” approach consists in combining learners’ motoric actions with physiological responses and data about the learning contexts. These data can be collected through multiple wearable sensors and Internet of Things (IoT) devices. This Hackathon table will confront with three main challenges arising from the analysis and valorisation of multimodal datasets: 1) the data collection and storing, 2) the data annotation, 3) the data processing and exploitation. Some research questions which will be considered in this Hackathon challenge are the following: how to process the raw sensor data streams and extract relevant features? which data mining and machine learning techniques can be applied? how can we compare two action recordings? How to combine sensor data with Experience API (xAPI)? what are meaningful visualisations for these data