Compiling Irregular Software to Specialized Hardware

High-level synthesis (HLS) has simplified the design process for energy-efficient hardware accelerators: a designer specifies an accelerator’s behavior in a “high-level” language, and a toolchain synthesizes register-transfer level (RTL) code from this specification. Many HLS systems produce efficient hardware designs for regular algorithms (i.e., those with limited conditionals or regular memory access patterns), but most struggle with irregular algorithms that rely on dynamic, data-dependent memory access patterns (e.g., traversing pointer-based structures like lists, trees, or graphs). HLS tools typically provide imperative, side-effectful languages to the designer, which makes it difficult to correctly specify and optimize complex, memory-bound applications. In this dissertation, I present an alternative HLS methodology that leverages properties of functional languages to synthesize hardware for irregular algorithms. The main contribution is an optimizing compiler that translates pure functional programs into modular, parallel dataflow networks in hardware. I give an overview of this compiler, explain how its source and target together enable parallelism in the face of irregularity, and present two specific optimizations that further exploit this parallelism. Taken together, this dissertation verifies my thesis that pure functional programs exhibiting irregular memory access patterns can be compiled into specialized hardware and optimized for parallelism. This work extends the scope of modern HLS toolchains. By relying on properties of pure functional languages, our compiler can synthesize hardware from programs containing constructs that commercial HLS tools prohibit, e.g., recursive functions and dynamic memory allocation. Hardware designers may thus use our compiler in conjunction with existing HLS systems to accelerate a wider class of algorithms than before

Air quality implications of developing the United Kingdom’s unconventional petroleum resources, with a focus on geological drilling and other analogous environments

Background & Aims: There are grave concerns that Unconventional Natural Gas (UNG) developments may severely impact air quality in the UK. To address these concerns, the thesis researches the two most significant risk-assessed hazards (i.e. drilling mud and combustion-related activities) by developing methods to identify physical phenomenon and source characteristics of key air pollutants - Particulate Matter (PM), Black Carbon (BC) and Nitrogen Oxides (NOX). Methods: The methods include personal air quality monitoring and statistical computing, including two pilot methods tested in Glasgow, before statistical computing is tested on data from the Preston New Road UNG site. Results: Statistical computing allows for long-term averaging and spatial temporal evaluation of industrial sites such as the Preston New Road drilling site, and when ratios (e.g. BC: NOX) are used, can detect discrete industrial and vehicular sources. Lastly, a review of PM on drilling rigs indicated high occupational exposures, which could cause respiratory disease, the chemicals within oil-based mad formulations were also found to pose a significant respiratory hazard. Conclusions: Air pollution from UNG at the Preston New Road site was less significant than conjecture and was less impactful than a nearby dairy farm. However, drilling mud exposures may present a high-risk occupational respiratory hazard to workers on modern onshore drilling rigs both from the quantity of airborne PM and from hazardous chemical dust. The developed methods also offer improved and cost-effective methods for source evaluation studies which could be implemented within most air pollution microenvironments.Background & Aims: There are grave concerns that Unconventional Natural Gas (UNG) developments may severely impact air quality in the UK. To address these concerns, the thesis researches the two most significant risk-assessed hazards (i.e. drilling mud and combustion-related activities) by developing methods to identify physical phenomenon and source characteristics of key air pollutants - Particulate Matter (PM), Black Carbon (BC) and Nitrogen Oxides (NOX). Methods: The methods include personal air quality monitoring and statistical computing, including two pilot methods tested in Glasgow, before statistical computing is tested on data from the Preston New Road UNG site. Results: Statistical computing allows for long-term averaging and spatial temporal evaluation of industrial sites such as the Preston New Road drilling site, and when ratios (e.g. BC: NOX) are used, can detect discrete industrial and vehicular sources. Lastly, a review of PM on drilling rigs indicated high occupational exposures, which could cause respiratory disease, the chemicals within oil-based mad formulations were also found to pose a significant respiratory hazard. Conclusions: Air pollution from UNG at the Preston New Road site was less significant than conjecture and was less impactful than a nearby dairy farm. However, drilling mud exposures may present a high-risk occupational respiratory hazard to workers on modern onshore drilling rigs both from the quantity of airborne PM and from hazardous chemical dust. The developed methods also offer improved and cost-effective methods for source evaluation studies which could be implemented within most air pollution microenvironments

Negotiating Climate Change in Crisis

"Climate change negotiations have failed the world. Despite more than thirty years of high-level, global talks on climate change, we are still seeing carbon emissions rise dramatically. This edited volume, comprising leading and emerging scholars and climate activists from around the world, takes a critical look at what has gone wrong and what is to be done to create more decisive action. Composed of twenty-eight essays—a combination of new and republished texts—the anthology is organised around seven main themes: paradigms; what counts?; extraction; dispatches from a climate change frontline country; governance; finance; and action(s). Through this multifaceted approach, the contributors ask pressing questions about how we conceptualise and respond to the climate crisis, providing both ‘big picture’ perspectives and more focussed case studies. This unique and extensive collection will be of great value to environmental and social scientists alike, as well as to the general reader interested in understanding current views on the climate crisis.

Britain’s Other D-Day: The Politics of Decimalisation

Some commentators have seen the introduction of decimal currency in the UK as part of a broader process of Europeanisation, driven by a zeal for modernisation, and leading to an abandonment of a traditional British exceptionalism. This thesis will argue that this view is false, and that the modernisation of the currency was an essentially conservative reform. In preserving the existing pound sterling, the Government was keen to maintain the supposed prestige of the currency, and the retention of the name ‘penny’ for the minor unit was based on an appeal to the public’s perceived adherence to tradition. There is little evidence that either the fact of decimalisation per se, or the choice of a system based on the existing pound, was influenced by Britain's attempts to gain entry to the European Economic Community, or indeed any desire to emulate wider European practice. In fact, by far the more important external stimulus to action by the British authorities was the decimalisation of the currencies in the 1960s by successive Commonwealth countries, South Africa, Australia and New Zealand, which left the UK, in the mid-1960s with the prospect of being virtually the only country in the world operating a non-decimal currency. However, I will argue that, although the influence of the decisions made in Australia and New Zealand was important, it was limited in scope. Whilst the UK was content to follow the lead of its Commonwealth partners in decimalising its currency, it did so on the basis of the existing £ unit, rather than the 10-shilling basis favoured in South Africa, Australia and New Zealand. It did so, despite significant internal opposition from retail and other interests, largely as a result of an unlikely alliance between the City of London, anxious to preserve the international status of the pound as a reserve currency, and a Labour government with decidedly conservative views on the traditional image of the pound