Reasoning with sorted-pareto dominance and other qualitative and partially ordered preferences in soft constraints

In decision making problems where we need to choose a particular decision or alternative from a set of possible choices, we often have some preferences which determine if we prefer one decision over another. When these preferences give us an ordering on the decisions that is complete, then it is easy to choose the best or one of the best decisions. However it often occurs that the preferences relation is partially ordered, and we have no best decision. In this thesis, we look at what happens when we have such a partial order over a set of decisions, in particular when we have multiple orderings on a set of decisions, and we present a framework for qualitative decision making. We look at the different natural notions of optimal decision that occur in this framework, which gives us different optimality classes, and we examine the relationships between these classes. We then look in particular at a qualitative preference relation called Sorted-Pareto Dominance, which is an extension of Pareto Dominance, and we give a semantics for this relation as one that is compatible with any order-preserving mapping of an ordinal preference scale to a numerical one. We apply Sorted-Pareto dominance to a Soft Constraints setting, where we solve problems in which the soft constraints associate qualitative preferences to decisions in a decision problem. We also examine the Sorted-Pareto dominance relation in the context of our qualitative decision making framework, looking at the relevant optimality classes for the Sorted-Pareto case, which gives us classes of decisions that are necessarily optimal, and optimal for some choice of mapping of an ordinal scale to a quantitative one. We provide some empirical analysis of Sorted-Pareto constraints problems and examine the optimality classes that result.

Between respectability and disgrace: schismogenesis and the regeneration of inequality, stigma and social exclusion in Limerick

The thesis examines cultural processes underpinning the emergence, institutionalisation and reproduction of class boundaries in Limerick city. The research aims to bring a new understanding to the contemporary context of the city’s urban regeneration programme. Acknowledging and recognising other contemporary studies of division and exclusion, the thesis creates a distinctive approach which focuses on uncovering the cultural roots of inequality, educational disadvantage, stigma and social exclusion and the dynamics of their social reproduction. Using Bateson’s concept of schismogenesis (1953), the thesis looks to the persistent, but fragmented culture of community and develops a heuristic ‘symbolic order of the city’. This is defined as “…a cultural structure, the meaning making aspect of hierarchy, the categorical structures of world understanding, the way Limerick people understand themselves, their local and larger world” (p. 37). This provides a very different departure point for exploring the basis for urban regeneration in Limerick (and everywhere). The central argument is that if we want to understand the present (multiple) crises in Limerick we need to understand the historical, anthropological and recursive processes underpinning ‘generalised patterns of rivalry and conflict’. In addition to exploring the historical roots of status and stigma in Limerick, the thesis explores the mythopoesis of persistent, recurrent narratives and labels that mark the boundaries of the city’s identities. The thesis examines the cultural and social function of ‘slagging’ as a vernacular and highly particularised form of ironic, ritualised and, often, ‘cruel’ medium of communication (often exclusion). This is combined with an etymology of the vocabulary of Limerick slang and its mythological base. By tracing the origins of many normalised patterns of Limerick speech ‘sayings’, which have long since forgotten their roots, the thesis demonstrates how they perform a significant contemporary function in maintaining and reinforcing symbolic mechanisms of inclusion/exclusion. The thesis combines historical and archival data with biographical interviews, ethnographic data married to a deep historical hermeneutic analysis of this political community.

Cost savings from relaxation of operational constraints on a power system with high wind penetration

Wind energy is predominantly a nonsynchronous generation source. Large-scale integration of wind generation with existing electricity systems, therefore, presents challenges in maintaining system frequency stability and local voltage stability. Transmission system operators have implemented system operational constraints (SOCs) in order to maintain stability with high wind generation, but imposition of these constraints results in higher operating costs. A mixed integer programming tool was used to simulate generator dispatch in order to assess the impact of various SOCs on generation costs. Interleaved day-ahead scheduling and real-time dispatch models were developed to allow accurate representation of forced outages and wind forecast errors, and were applied to the proposed Irish power system of 2020 with a wind penetration of 32%. Savings of at least 7.8% in generation costs and reductions in wind curtailment of 50% were identified when the most influential SOCs were relaxed. The results also illustrate the need to relax local SOCs together with the system-wide nonsynchronous penetration limit SOC, as savings from increasing the nonsynchronous limit beyond 70% were restricted without relaxation of local SOCs. The methodology and results allow for quantification of the costs of SOCs, allowing the optimal upgrade path for generation and transmission infrastructure to be determined.