Investigating the Physical Properties of Planetary Surfaces using the Huygens Penetrometer

The Huygens probe landed on the unknown surface of Titan on 14 January 2005. Onboard, a small, protruding hemispherical-tipped penetrometer, ACC-E, part of the Surface Science Packagem impacted the surface returning a short ~20 ms force signature of the mechanical resistance of the ground. The purpose of this thesis is to examine the response of an identical penetrometer to various terrestrial target materials and provide an insight into the penetrometer's performance and assess its capability. Signatures collected at the Huygens impact speed of both natural and artificial material targets in the laboratory are examined using various descriptive statistical measures. Structural and textural properties are identified and the penetrometer's response to granular targets, both wet and dry, is examined. Mitigation of the effects of target boundaries and velocity dependence of the signatures are both considered. Terrestrial fieldwork penetrometry is presented that demonstrates that even for short penetration depths the sensor is capable of distinguishing several types of geological surface features. A physical model extended for layered targets is presented and applied to laboratory data. Using the results from the laboratory and fieldwork, together with more specific experiments, a possible interpretation of the signature returned from Titan is presented and discussed within the context of recent findings from other investigations

A novel thick-film screen printed electrical conductivity sensor for measurement of liquid and soil conductivity

Results are reported from an initial evaluation of a novel conductivity sensor that has been incorporated onto a multi-element thick film sensor array designed for soil and water analysis. The new sensor exhibits a more repeatable cell constant of approximately 0.15 cm-1 over a wider range of conductivities compared with conductivity sensor designs previously employed in the sensor array. The new sensor is currently performing very well in an investigation of soil structural properties where its output is being correlated with soil water content in a study of different soil porosities

Stability of cooperation in societies of emotional and moody agents

It is well documented that cooperation may not be achieved in societies where self-interested agents are engaging in Prisoner’s Dil

Engine oil acidity detection using solid state ion selective electrodes

Initial results from oil acidity measurements using thick film electrodes are presented. The results suggest that as the oil degrades, its pH/acidity follows a specific trend. Furthermore, an investigation into the feasibility of detecting changes in oil acidity (i.e. TAN value) using ion selective electrodes fabricated utilising thick film technology is presented. The thick-film (screen printing) technique is a decent means for the mass production of rugged, compact and disposable sensors as many such devices can be printed at the same time making them very cost effective to manufacture. Thick-Film ion selective and reference electrodes were fabricated, calibrated and tested in different oil samples varying its acidity. Ruthenium oxide (RuO2) pH sensitive electrodes were screen printed and were used against silver/silver chloride (Ag/AgCl) reference electrodes as well as a commercial glass Ag/AgCl reference electrode. The potentiometric sets of electrodes were calibrated in pH 4, 7 and 10 buffers in a cyclic manner and the voltage was recorded using a high input impedance voltmete

On the role of mobility and interaction topologies in social dilemmas

Numerous studies have developed and analysed strategies for maximising utility in social dilemmas from both an individual agent's perspective and more generally from the viewpoint of a society. In this paper we bring this body of work together by investigating the success of a wide range of strategies in environments with varying characteristics, comparing their success. In particular we study within agent-based simulations, different interaction topologies, agents with and without mobility, and strategies with and without adaptation in the form of reinforcement learning, in both competitive and cooperative settings represented by the Prisoner's Dilemma and the Stag Hunt, respectively. The results of our experiments show that allowing agents mobility decreases the level of cooperation in the society of agents, due to singular interactions with individual opponents that limit the possibility for direct reciprocity. Unstructured environments similarly support a greater number of singular interactions and thus higher levels of defection in the Prisoner's Dilemma. In the Stag Hunt, strategies that prioritise risk taking show a greater level of success regardless of environment topology. Our range of experiments yield new insights into the role that mobility and interaction topologies play in the study of cooperation in agent societies

Stability of Human-Inspired Agent Societies

Models of emotion, particularly those based on the Ortony, Clore, and Collins (OCC) account of emotions, have been used as part of agents' decision making processes to explore their effects on cooperation within social dilemmas [7, 19, 22]. We analyse two different interpretations of OCC agents. Firstly, Emotional agents that decide their action using only a model of emotions. To analyse the possibility of evolutionary stability of these agents we use the Prisoner's Dilemma game. We contrast the results with the second interpretation of an OCC agent, the Moody agent [7], which additionally uses a psychology-grounded model of mood. Our analysis highlights the different strategies that are needed to achieve success as a society in terms of both stability and cooperation, in the iterated Prisoner's Dilemma. The Emotional agents are better suited playing against a mixed group of agents with differing strategies than the Moody agents are. The Moody agents are more successful than the Emotional agents when only one strategy exists in the society