Algorithms for the Analysis of Spatio-Temporal Data from Team Sports

Modern object tracking systems are able to simultaneously record trajectories—sequences of time-stamped location points—for large numbers of objects with high frequency and accuracy. The availability of trajectory datasets has resulted in a consequent demand for algorithms and tools to extract information from these data. In this thesis, we present several contributions intended to do this, and in particular, to extract information from trajectories tracking football (soccer) players during matches. Football player trajectories have particular properties that both facilitate and present challenges for the algorithmic approaches to information extraction. The key property that we look to exploit is that the movement of the players reveals information about their objectives through cooperative and adversarial coordinated behaviour, and this, in turn, reveals the tactics and strategies employed to achieve the objectives. While the approaches presented here naturally deal with the application-specific properties of football player trajectories, they also apply to other domains where objects are tracked, for example behavioural ecology, traffic and urban planning

Investigating information processing within the brain using multi-electrode array (MEA) electrophysiology data

How a stimulus, such as an odour, is represented in the brain is one of the main questions in neuroscience. It is becoming clearer that information is encoded by a population of neurons, but, how the spiking activity of a population of neurons conveys this information is unknown. Several population coding hypotheses have formulated over the years, and therefore, to obtain a more definitive answer as to how a population of neurons represents stimulus information we need to test, i.e. support or falsify, each of the hypotheses. One way of addressing these hypotheses is to record and analyse the activity of multiple individual neurons from the brain of a test subject when a stimulus is, and is not, presented. With the advent of multi electrode arrays (MEA) we can now record such activity. However, before we can investigate/test the population coding hypotheses using such recordings, we need to determine the number of neurons recorded by the MEA and their spiking activity, after spike detection, using an automatic spike sorting algorithm (we refer to the spiking activity of the neurons extracted from the MEA recordings as MEA sorted data). While there are many automatic spike sorting methods available, they have limitations. In addition, we are lacking methods to test/investigate the population coding hypotheses in detail using the MEA sorted data. That is, methods that show whether neurons respond in a hypothesised way and, if they do, shows how the stimulus is represented within the recorded area. Thus, in this thesis, we were motivated to, firstly, develop a new automatic spike sorting method, which avoids the limitations of other methods. We validated our method using simulated and biological data. In addition, we found our method can perform better than other standard methods. We next focused on the population rate coding hypothesis (i.e. the hypothesis that information is conveyed in the number of spikes fired by a pop- ulation of neurons within a relevant time period). More specifically, we developed a method for testing/investigating the population rate coding hypothesis using the MEA sorted data. That is, a method that uses the multi variate analysis of variance (MANOVA) test, where we modified its output, to show the most responsive subar- eas within the recorded area. We validated this using simulated and biological data. Finally, we investigated whether noise correlation between neurons (i.e. correlations in the trial to trial variability of the response of neurons to the same stimulus) in a rat's olfactory bulb can affect the amount of information a population rate code conveys about a set of stimuli. We found that noise correlation between neurons was predominately positive, which, ultimately, reduced the amount of information a population containing >45 neurons could convey about the stimuli by ~30%

Neither “Headache” Nor “Illness:” The False Narrative of Syphilis and its Origin in Europe

In this paper I argue that the master narrative of the origin of syphilis in Europe, known as the Columbian Theory does not hold up to historical review since it does not contain enough concrete evidence for we as historians to be comfortable with as the master narrative. To form my argument I use the writings of Girolamo Fracastoro, an Italian physician known for coining the term “syphilis,” as the basis when I review the journal of Christopher Columbus. I review his journal, which chronicles the first voyage to the Americas, to see if there is any connection between the syphilis disease and him or his crew. After reviewing this evidence I turn to the secondary source literature referring to historians who support the Columbian Theory on syphilis and those who criticize it. I use the lack of evidence to connect Columbus to the syphilis disease to counter what supporters of the Columbian Theory argue and explain that the Columbian Theory can’t be used for the master narrative as the origin of syphilis in Europe

INFLATIONARY TRUTH-THEORETIC SEMANTICS

I argue that satisfaction and reference—and therefore, truth—are multiply realizable properties. I advocate a novel approach motivated by a commitment to the robustness and fruitfulness of truth-theoretic approaches to natural language semantics. DEFLATIONISM: Philosophers keen on deflating the metaphysical pretensions of truth theories claim that we need not appeal to a substantive truth-property. Recently, however, some philosophers have sought to combine deflationism about truth with the view that our concept of truth or the truth-predicate can play an important role in natural language semantics. TRUTH-THEORETIC SEMANTICS: The goal of a formal semantic theory of a natural language is to provide both the semantic values of that language’s lexically primitive items as well as the semantically significant modes of combining those basic elements into meaningful and more complex expressions. Most approaches have in common a commitment to finite stateability and compositionality as well as a commitment to something like Davidson’s “Convention T.” PLURALISM: Pluralists about truth argue that different areas of discourse have different truth-properties. Can pluralism successfully be combined with a commitment to truth-theoretic semantics? OPEN SEMANTIC FUNCTIONALISM: The pluralist approaches to truth are unsatisfactory for a variety of reasons. The only option, I argue, is to regard truth as multiply-realizable. Specifically, we should view the set of truth’s realizers as possessing non-actual members—as being “open.” Truth is defined in the usual way in terms of reference and satisfaction, but these latter two relations are to be understood as multiply realizable but open. The property of truth can be specified using the Ramsey/Lewis method. My final view—Open Semantic Functionalism—respects compositionality and finite stateability, avoids triviality, handles plurality, and fits with robust, explanatorily significant natural language semantic theories

Determination of effective porosity of soil materials

The performance of a compacted soil liner is partly a function of the porosity, which is important because the transport of materials through the liner occurs via the pore space. This project studies the pore spaces of compacted soil materials to estimate the effective porosity, which is the portion of the pore space where the most rapid transport of leachate occurs. Pore space of three soil materials, till, loess. and paleosol, was studied by using mercury intrusion porosimetry, water absorption, and image analysis. These analyses provided cumulative porosity curves from which the pore size distribution of soil samples were estimated. Theory was developed to estimate the effective porosity of a compacted soil material based upon a model of its pore size distribution and pore continuity. The effective porosities of compacted till. loess. and paleosol materials are estimated-to be 0.04. 0.08. and 0.09. respectively. These values are 10 to 20% of the total porosities. Comparisons between measured and predicted C1 travel times through compacted soil samples were made in order to verify the estimated effective porosities. The estimated effective porosities are reasonable because predicted C1~ first breakthrough times are similar to the measured first breakthrough times in the,soils studied. For these three soils predicted first breakthrough times are 5 to 10 times earlier when effective porosity is used.in the Darcy-equation based calculations as compared to Darcy-equation-based calculations that utilize total porosity