Content-aware compression for big textual data analysis

A substantial amount of information on the Internet is present in the form of text. The value of this semi-structured and unstructured data has been widely acknowledged, with consequent scientific and commercial exploitation. The ever-increasing data production, however, pushes data analytic platforms to their limit. This thesis proposes techniques for more efficient textual big data analysis suitable for the Hadoop analytic platform. This research explores the direct processing of compressed textual data. The focus is on developing novel compression methods with a number of desirable properties to support text-based big data analysis in distributed environments. The novel contributions of this work include the following. Firstly, a Content-aware Partial Compression (CaPC) scheme is developed. CaPC makes a distinction between informational and functional content in which only the informational content is compressed. Thus, the compressed data is made transparent to existing software libraries which often rely on functional content to work. Secondly, a context-free bit-oriented compression scheme (Approximated Huffman Compression) based on the Huffman algorithm is developed. This uses a hybrid data structure that allows pattern searching in compressed data in linear time. Thirdly, several modern compression schemes have been extended so that the compressed data can be safely split with respect to logical data records in distributed file systems. Furthermore, an innovative two layer compression architecture is used, in which each compression layer is appropriate for the corresponding stage of data processing. Peripheral libraries are developed that seamlessly link the proposed compression schemes to existing analytic platforms and computational frameworks, and also make the use of the compressed data transparent to developers. The compression schemes have been evaluated for a number of standard MapReduce analysis tasks using a collection of real-world datasets. In comparison with existing solutions, they have shown substantial improvement in performance and significant reduction in system resource requirements.

Options to advance co-ordination and analysis of climate data in Europe

Systematic, high-quality observations of the atmosphere, oceans and terrestrial environments are required to improve understanding of climate characteristics and the consequences of climate change. The overall aim of this report is to carry out a comparative assessment of approaches taken to addressing the state of European observations systems and related data analysis by some leading actors in the field. This research reports on approaches to climate observations and analyses in Ireland, Switzerland, Germany, The Netherlands and Austria and explores options for a more coordinated approach to national responses to climate observations in Europe. The key aspects addressed are: an assessment of approaches to develop GCOS and provision of analysis of GCOS data; an evaluation of how these countries are reporting development of GCOS; highlighting best practice in advancing GCOS implementation including analysis of Essential Climate Variables (ECVs); a comparative summary of the differences and synergies in terms of the reporting of climate observations; an overview of relevant European initiatives and recommendations on how identified gaps might be addressed in the short to medium term.

"On our way": identities and representations of African women seeking asylum in Ireland

This thesis provides the first explicit Postcolonial study of asylum in the Irish context that integrates Black Feminist analyses of intersectional identity with Postcolonial Feminist theories of representation. African women seeking asylum in the Republic of Ireland were key political instruments used by the state to re-draw racial lines. The study examines how, for a group of African women “On their Way” through asylum, identity and representation work hand in hand to force identities, subaltern spaces and bodies to occupy them. Rich biographical data is gathered through mixed art and drama methods over two intensive participatory research projects conducted in a small Irish city. Data analysis critically examines the poetics (practices that signify) and politics (the powers that govern these practices) and affective economies of global and local NGO visual representations, exposing how they consume, fragment, and appropriate African women’s identities and bodies. Though hypervisible, the women themselves “cannot speak”. The women in the study reported feeling “tired” and “used”. Asking “What work are they doing as they do asylum?” the study finds that black female identities and bodies are forced to perform political, cultural, emotional and material labour on their way through this context of Irish asylum. The author argues that Postcolonial Asylum is a performative encounter that re-scripts colonial race/class/gender discourse through a humanitarian alibi to naturalize European/white supremacy, reinscribe patriarchal power and justify racialised incarceration of bodies seeking asylum in the North. This study takes an interdisciplinary approach that centralizes Black and Postcolonial Feminist theory and innovates Participatory Art-Based Action methodology. Black and Postcolonial feminisms can recognize, theorize and replenish black female political and intellectual agency. Participatory Action research, if grounded in Black feminist epistemology and ethics, can allow participants to “speak back” to what is already said about them in spaces of convivial self-representation.