Combining and choosing case base maintenance algorithms

Case-Based Reasoning (CBR) uses past experiences to solve new problems. The quality of the past experiences, which are stored as cases in a case base, is a big factor in the performance of a CBR system. The system's competence may be improved by adding problems to the case base after they have been solved and their solutions verified to be correct. However, from time to time, the case base may have to be refined to reduce redundancy and to get rid of any noisy cases that may have been introduced. Many case base maintenance algorithms have been developed to delete noisy and redundant cases. However, different algorithms work well in different situations and it may be difficult for a knowledge engineer to know which one is the best to use for a particular case base. In this thesis, we investigate ways to combine algorithms to produce better deletion decisions than the decisions made by individual algorithms, and ways to choose which algorithm is best for a given case base at a given time. We analyse five of the most commonly-used maintenance algorithms in detail and show how the different algorithms perform better on different datasets. This motivates us to develop a new approach: maintenance by a committee of experts (MACE). MACE allows us to combine maintenance algorithms to produce a composite algorithm which exploits the merits of each of the algorithms that it contains. By combining different algorithms in different ways we can also define algorithms that have different trade-offs between accuracy and deletion. While MACE allows us to define an infinite number of new composite algorithms, we still face the problem of choosing which algorithm to use. To make this choice, we need to be able to identify properties of a case base that are predictive of which maintenance algorithm is best. We examine a number of measures of dataset complexity for this purpose. These provide a numerical way to describe a case base at a given time. We use the numerical description to develop a meta-case-based classification system. This system uses previous experience about which maintenance algorithm was best to use for other case bases to predict which algorithm to use for a new case base. Finally, we give the knowledge engineer more control over the deletion process by creating incremental versions of the maintenance algorithms. These incremental algorithms suggest one case at a time for deletion rather than a group of cases, which allows the knowledge engineer to decide whether or not each case in turn should be deleted or kept. We also develop incremental versions of the complexity measures, allowing us to create an incremental version of our meta-case-based classification system. Since the case base changes after each deletion, the best algorithm to use may also change. The incremental system allows us to choose which algorithm is the best to use at each point in the deletion process.

Diverse heritage: exploring literary identity in the American Southwest

Since the age of colonisation, the territory of New Mexico has been exposed to a diversity of cultural influence. Throughout recorded history various forces have battled for control of this territory, resulting in a continuous redefinition of its political, geographic and economic boundaries. Early representations of the Southwest have been defined as “strategies of negotiation” between Anglo, Hispanic and Native populations, strategies that are particularly evident in the territory of New Mexico. The contemporary identity of regions like northern New Mexico have destabilised the notion of what constitutes racial purity in regions which are defined by diversity. This thesis aims to evaluate the literary history of northern New Mexico in order to determine how exposure to a diversity of cultural influence has affected the region’s identity. An analysis of Anglo and Native writers from northern New Mexico will illustrate that these racial groups were influenced by the same geographic landscape. As such, their writing displays many characteristics unique to the region. In providing a comparative analysis of Native and Anglo authors from northern New Mexico, this thesis seeks to demonstrate commonalities of theme, structure and content. In doing so this research encourages a new perspective on New Mexico writing one which effectively de-centres contemporary notions of what the American canon should be.

Dairy-Met: compositional metagenomic analysis of milk and cheeses

Unpasteurised milk and many cheeses contain a diverse microbiological population. These microorganisms play important roles in dairy foods and can, for example, contribute to the development of flavours and aromas, determine safety, cause spoilage or enhance the health of the consumer. It is thus important to understand thoroughly the microorganisms present in these food types. Traditional culture dependent and culture-independent methods have provided much detail regarding the microbial content of dairy foods. However, the development of next-generation DNA sequencing technologies has revolutionised our knowledge of complex microbial environments. Throughout this thesis we observe the benefits of applying these technologies to provide a detailed understanding of the bacterial content of dairy foods, including those present in milk pre- and post-pasteurisation, Irish farmhouse cheeses and commercially produced cheeses which encounter a discolouration defect, as well as to study genomic changes in microbes associated with dairy foods. Through the application of these state-of-the-art technologies we identified the presence of microorganisms not previously associated with dairy foods.

Developing executive capability — banking and beyond

The transition to becoming a leader is perhaps the least understood and most difficult in business. This Portfolio of Exploration examines the development of conscious awareness and meaning complexity as key transformational requirements to operate competently at leadership level and to succeed in a work environment characterised by change and complexity. It recognises that developing executive leadership capability is not just an issue of personality increasing what we know or expertise. It requires development of complexity in terms of how we know ourselves, relate to others, construe leadership and organisation, problem solve in business and understand the world as a whole. The exploration is grounded in the theory of adult mental development as outlined by Robert Kegan (1982, 1994) and in his collaborations with Lisa Laskow Lahey (2001, 2009). The theory points to levels of consciousness which impact on how we make meaning of and experience the world around us and respond to it. Critically it also points to transformational processes which enable us to evolve how we make meaning of our world as a means to close the mismatch between the demands of this world and our ability to cope. The exploration is laid out in three stages. Using Kegan’s (1982, 1994) theory as a framework it begins with a reflection of my career to surface how I made meaning of banking, management and subsequently leadership. In stage two I engage with a range of source thinkers in the areas of leadership, decision making, business, organisation, growth and complexity in a transformational process of developing greater conscious and complex understanding of organisational leadership (also recognising ever increasing complexity in the world). Finally, in stage three, I explore how qualitative changes as a result of this transformational effort have benefitted my professional, leadership and organisational capabilities.