Projection-free methods for solving smooth convex bilevel optimisation problems

When faced with multiple minima of an "inner-level" convex optimisation problem, the convex bilevel optimisation problem selects an optimal solution which also minimises an auxiliary "outer-level" convex objective of interest. Bilevel optimisation requires a different approach compared to single-level optimisation problems since the set of minimisers for the inner-level objective is not given explicitly. In this thesis, we propose new projection-free methods for convex bilevel optimisation which require only a linear optimisation oracle over the base domain. We provide convergence guarantees for both inner- and outer-level objectives that hold under our proposed projection-free methods. In particular, we highlight how our guarantees are affected by the presence or absence of an optimal dual solution. Lastly, we conduct numerical experiments that demonstrate the performance of the proposed methods

The Return of the Regulatory State: Nation-States as Policy Actors in Digital Platform Governance

This chapter explores the rise of digital platform regulation by nation-states as a manifestation of the rise of "big state" nationalism and the decline of the open Internet

Seeing and Nothingness: Aposiopetic Cinema and Sartrean Spectatorship

Film scholarship has considered the affective qualities of cinema’s patterns of closure, but has neglected the methods and implications of narrative openness. Generally, entirely open-ended films are considered on a case-by-case basis and are not situated in dialogue with one another. In such cases, these films’ deviations have 1) been considered through a lens of narrative theory, and 2) been likened to “ellipses.” Considering open-ended films as provocative only by virtue of their narrative deviation, or as carrying the affective weight of an ellipsis, does not account for the often shocking, unsettling, or profoundly moving experiences these films generate. In this thesis, I bring together a selection of open-ended, unresolved narrative films and read them as “aposiopetic,” a label borrowed from rhetoric and literature that more accurately accounts for the abruptness of their irresolution than existing structural and affective descriptions. In exploring the affect generated by this structural deviation, I undertake a phenomenological analysis, explicitly taking up the view of nothingness argued by Jean-Paul Sartre in Being and Nothingness (1943). Across five chapters, this thesis specifically considers films about missing, disappeared, and ontologically dubious characters, and suggests that the affect engendered by these films’ regimes of ambiguity, silence, absence and negation echoes Sartre’s contention that “nothingness is right inside being, in its heart, like a worm.” I find that in the aposiopetic film’s lack of closure, there arises a provocation of imagination, anxiety, freedom, and nothingness that generates a rich spectatorial experience. This thesis highlights how a film might reify abstract philosophical ideas not just within its narrative content and through its form, but also in its extra-textual afterlife—an afterlife that is uniquely encouraged and facilitated in the aposiopetic mode

Australia's National Electricity Market: Bidding rules, market power and wholesale electricity prices

Wholesale prices for the generation of electricity markedly increased in 2022 and 2023. These costs, the most significant component of the final electricity price paid by consumers, were estimated, by the Australian Energy Regulator, to be 30-40% of a typical residential bill in 2022-2023 and 50-60% in 2023-2024. This substantive rise has been driven by increases in wholesale charges of up to 68% in 2023-2024 and follow increases of up to nearly 50% the previous financial year. These wholesale price increases have been driven by: • Generation companies exercising market power through the supply bidding and rebidding rules governing Australia’s National Electricity Market, and • Generation companies negotiating contracts in the parallel markets for financial contracts which inform the prices these companies bid to supply generation capacity. The Australian Energy Market Commission, and affirmed by the Australian Energy Regulator, interprets the National Electricity Law—that underpins the market’s bidding and rebidding rules—as permitting the transient (temporary) exercise of market power not sustained market power over a period of time. These two regulators, which administer the National Electricity Rules (NER) and review the performance of the National Electricity Market (NEM) respectively, are not transparent about their definitions of ‘transient’, ‘sustained’, or ‘period of time’. Market power is market power, transient or sustained. The exercise of market power, over any period, produces outcomes contrary to a competitive market which is supposed to yield the lowest possible prices for consumers. The NEM was purportedly designed to be a competitive market. It is a market, however, with high concentrations of generation capacity across all its regions which make it fertile ground for uncompetitive behaviour. The vulnerability of the NEM to market power, and its persistence since the NEM commenced in December 1998, has been recognised by regulators, market participants and all Australian governments. Changes have been made to the NEM’s supply bidding and rebidding rules and new forms of market performance monitoring have been implemented. Yet these have not prevented the record increases in wholesale electricity prices during recent years. Bidding behaviour to supply generation capacity, in conjunction with the speculative behaviour of generation companies in the financial contract markets about future electricity prices in the NEM, present exemplary evidence of ongoing price gouging and unfair pricing practices

Model Reduction for the Kuramoto-Sakaguchi Model: analyzing the effect of non-entrained rogue oscillators

The Kuramoto-Sakaguchi model is a paradigmatic model of coupled oscillator system which displays collective behaviour. This thesis is concerned with better understanding of the model through construction of lowerdimensional reduced models that are more tractable for analysis. The role of non-entrained rogue oscillators on the synchronized oscillators is highlighted. After reviewing traditional analysis via mean-field theory in the thermodynamic limit of infinitely many oscillators, we proceed to construct reduced models for finite-size systems, where we investigate on how the effects of rogue oscillators should be incorporated. We first describe the rogue oscillators’ effect via averaging, leading to a closed deterministic system that involves the synchronized oscillators only. We perform model reduction analysis on the system via the collective coordinate framework. It is demonstrated that inclusion of the effect of rogue oscillators is crucial for obtaining an accurate description of the system. A new non-linear ansatz is introduced which significantly improves the accuracy of the reduced system, both for finite-size systems and in the thermodynamic limit. We then analyze the fluctuation of rogue oscillator’s effect around their mean, by constructing stochastic process approximations. It is demonstrated that utilizing an Ornstein- Uhlenbeck process leads to stochastic reduced model that can capture the fluctuations exhibited in the full model. This thesis also adds to the mean-field theory analysis for Kuramoto-like model by performing meanfield analysis on the Kuramoto-Sakaguchi model with uniform intrinsic frequency distribution, which reviews that for a non-zero phase-offset parameter, the system exhibits an intricate transition to synchronization, with first-order transition to partial synchronization followed by a second-order transition to global synchronization

Locked Up & Locked Out: Incarceration & Children's Interests

In this thesis I question the justifiability of the current practice of juvenile incarceration. I argue that children have rights borne out of both extrinsic and intrinsic interests. I suggest that the detained child's interests in development allow us to justify incarceration as a means of moral education. However, I conclude that the current practice of juvenile incarceration--as evidenced in Queensland--violates the detained child's rights to carefreeness, connection, and future autonomy. In doing so, the justifiability and permissibility of the practice is undermined

Disobedient Discourse: Mill, ContraPoints, and the Limits of Free Speech Norms

In this paper, I explore contemporary disagreement regarding protests against speakers deemed regressive or bigoted by progressive activists. I do so by examining the rationale, scope, and operation of free speech norms (i.e. non-legal standards that require people to respond to speech with tolerance). I specifically focus on the free speech norms defended by John Stuart Mill in his essay ‘On Liberty’. I contend that Mill’s free speech norms are well-justified and extend to protect the speech of regressive bigots in almost all circumstances. However, I also draw upon two arguments from Natalie Wynn’s video essay ‘The Witch Trials of J.K. Rowling’ to contend that Millian free speech norms present serious problems for marginalised people. I attempt to resolve this tension between Mill’s well-justified norms and their problematic implications for marginalised people by developing a concept of ‘disobedient discourse’ that is modelled after John Rawls’ account of civil disobedience and allows for free speech norms to be violated in circumstances of longstanding injustice

Wrestling with Monsters: Critique, Climate Change, and Comets

We live, as the Chinese saying supposedly goes, in interesting times. Žižek (2012) argues that our times constitute a state of permanent crisis. This sense of crisis is felt across material domains through climate change or geopolitics, to policy settings that respond to ‘crises’ in our bureaucracies. How are we to respond to such a state? In this chapter, I discuss Žižek’s call not to act, but to think. Žižek’s project uses psychoanalytic ideology critique to pose questions about the way people understand the ‘problems of society’. He uses the metaphors of masks and fantasy to unpack the way particular ‘truths’ are symbolic representations that act to construct hegemonic ideologies that define the world. The intellectual work of the academy—that which ‘has no practical use’ (Žižek, 2012. Counterpoints, 422, 32–44)—involves the interrogation and critique of these masks: to explore how the ways we perceive a problem can themselves be part of the problem. Faced with these complex, mediated rationalities, Žižek argues that there is often a push to act quickly, often in ways that do not create solutions. The challenge is to find ways to re-articulate the problems of our world in ways that transform our understanding and therefore the terrain of possibility. This chapter engages with this challenge through the lens of climate change and the school strike movement

Transient Chaos in Dissipative Chaotic Scattering

In this thesis we consider the influence of dissipative effects on dynamical systems whose unperturbed dynamics are already transiently chaotic. The class of systems we study have been used to model a wide range of physical processes, from celestial-mechanical motions to hydrodynamic flows, which are susceptible to such perturbations. We use existing theory on transient chaos and powerful numerical methods to gain a comprehensive understanding of the dynamics of these scattering systems in both conservative and dissipative settings, in terms of macroscopic quantities like the survival rate of trajectories in particular phase space regions, or the fractal scaling of basin boundaries between final states. We then propose a general framework, inspired by earlier work on pullback attractors, for understanding the qualitative differences and general phenomenology visible in the numeri cal results for the dissipative system. In particular, we find that features related to conditionally-invariant measures of the unperturbed system can be used to explain the observations of the dissipative system, even when the dynamics of each case are substantially different

An Integrative Investigation of Materialism: Exploring the Influence of Cultural Orientation, Political Orientation, and Status Threat

This thesis presents a series of studies aimed at exploring materialism and status consumption behavior. The first study examines the relationship between cultural orientation, materialism, and status consumption behavior, incorporating horizontal and vertical dimensions of individualism and collectivism (Singelis et al., 1995). Incorporating the horizontal and vertical dimensions of individualism and collectivism, it finds only vertical individualism positively predicts materialism and status consumption behavior while other cultural orientations have negative relations to them. The second study proposes that political orientation could be a potential predictor of materialism since previous research has shown political orientations predict different consumer behavior such as complaining behavior (e.g., Jung et al., 2017). It finds the effects of political orientation on materialism subcomponents, namely, materialism-success, centrality, and happiness. The third study examines the ways consumers engage in status restoration consumption behavior as a means to cope with different status-threatening situations. It finds consumers tend to show more status restoration consumption behavior when their social status is threatened compared to when their professional status is under threat, suggesting that social status threat could be more critical in consumer well-being. Collectively, this research contributes to the materialism and status consumption literature by suggesting a more comprehensive and nuanced relationship between cultural orientation, materialism, and status consumption, examining the personal factors that influence materialism such as cultural and political orientation, and exploring situational factors of status consumption behavior; for example, status-threatening situations. Practical implications are also discussed