Impact of non-optimal grounding of the CC2420 RFIC on a 802.15.4 Tyndall sensor wireless mote

The performance of an RF output matching network is dependent on integrity of the ground connection. If this connection is compromised in anyway, additional parasitic elements may occur that can degrade performance and yield unreliable results. Traditionally, designers measure Constant Wave (CW) power to determine that the RF chain is performing optimally, the device is properly matched and by implication grounded. It is shown that there are situations where modulation quality can be compromised due to poor grounding that is not apparent using CW power measurements alone. The consequence of this is reduced throughput, range and reliability. Measurements are presented on a Tyndall Mote using a CC2420 RFIC todemonstrate how poor solder contact between the ground contacts and the ground layer of the PCB can lead tothe degradation of modulated performance. Detailed evaluation that required the development of a new measurement definition for 802.15.4 and analysis is presented to show how waveform quality is affected while the modulated output power remains within acceptable limits.

Finding optimal alternatives based on efficient comparative preference inference

Choosing the right or the best option is often a demanding and challenging task for the user (e.g., a customer in an online retailer) when there are many available alternatives. In fact, the user rarely knows which offering will provide the highest value. To reduce the complexity of the choice process, automated recommender systems generate personalized recommendations. These recommendations take into account the preferences collected from the user in an explicit (e.g., letting users express their opinion about items) or implicit (e.g., studying some behavioral features) way. Such systems are widespread; research indicates that they increase the customers' satisfaction and lead to higher sales. Preference handling is one of the core issues in the design of every recommender system. This kind of system often aims at guiding users in a personalized way to interesting or useful options in a large space of possible options. Therefore, it is important for them to catch and model the user's preferences as accurately as possible. In this thesis, we develop a comparative preference-based user model to represent the user's preferences in conversational recommender systems. This type of user model allows the recommender system to capture several preference nuances from the user's feedback. We show that, when applied to conversational recommender systems, the comparative preference-based model is able to guide the user towards the best option while the system is interacting with her. We empirically test and validate the suitability and the practical computational aspects of the comparative preference-based user model and the related preference relations by comparing them to a sum of weights-based user model and the related preference relations. Product configuration, scheduling a meeting and the construction of autonomous agents are among several artificial intelligence tasks that involve a process of constrained optimization, that is, optimization of behavior or options subject to given constraints with regards to a set of preferences. When solving a constrained optimization problem, pruning techniques, such as the branch and bound technique, point at directing the search towards the best assignments, thus allowing the bounding functions to prune more branches in the search tree. Several constrained optimization problems may exhibit dominance relations. These dominance relations can be particularly useful in constrained optimization problems as they can instigate new ways (rules) of pruning non optimal solutions. Such pruning methods can achieve dramatic reductions in the search space while looking for optimal solutions. A number of constrained optimization problems can model the user's preferences using the comparative preferences. In this thesis, we develop a set of pruning rules used in the branch and bound technique to efficiently solve this kind of optimization problem. More specifically, we show how to generate newly defined pruning rules from a dominance algorithm that refers to a set of comparative preferences. These rules include pruning approaches (and combinations of them) which can drastically prune the search space. They mainly reduce the number of (expensive) pairwise comparisons performed during the search while guiding constrained optimization algorithms to find optimal solutions. Our experimental results show that the pruning rules that we have developed and their different combinations have varying impact on the performance of the branch and bound technique.

Health care and neoliberalism in Ireland: withholding the gift and corrupting the social contract

The health of a nation tells much about the nature of a social contract between citizen and state. The way that health care is organised, and the degree to which it is equitably accessible, constitutes a manifestation of the effects of moments and events in that country's history. Using four case studies, this thesis uses a historical genealogical approach to explain the evolution of Ireland's particular version of health care provision. The total social fact of the gift relationship, central to all human relations, will be used to form a theoretical and conceptual framework on which to build an analysis of Ireland's health and welfare conditions. Additionally, social contract theory will enable an examination of the role of solidarity in relation to social expectations around health care provision. Through the analysis of these cases, the complex matrix of the influential forces that have shaped current conditions are exposed and revealed, enabling a critical understanding of the extent of acquiescence to the inequitable system that arguably exists. The vulnerability of citizens in need of care to the external and global effects of market forces and neoliberalism, therefore, becomes central to any argument for state-provided health and welfare. The hegemony of such forces can be seen to influence the manner in which the idea of individual self-reliance, in place of collective solidarity, is conceptualised and subsequently infiltrated into a range of aspects of the social world. For example, the particular discourse of the market and of economic concerns succeeds in shaping understandings of responsibilities around central areas of health and welfare. Similarly the 'possessor principle' can be seen to be misplaced within the context of health and social care, but yet has become normalised within this discourse. Within this matrix of complex influencing factors, the welfare state struggles to impose a balance between market values and social values. Responsibilities of the state to support and compensate its citizens for the ills of the market have become devalued, as the core values of classical liberalism have become distorted beyond recognition, leaving instead bare neoliberal concerns. This thesis traces the genealogical origins of this transition within the recent history of Irish health care and thereby reveals the embedding of individualism in place of solidarity, the on going reneging of the social contract and the corruption of the gift relationship.