Isoelastic Agents and Wealth Updates in Machine Learning Markets

Recently, prediction markets have shown considerable promise for developing flexible mechanisms for machine learning. In this paper, agents with isoelastic utilities are considered. It is shown that the costs associated with homogeneous markets of agents with isoelastic utilities produce equilibrium prices corresponding to alpha-mixtures, with a particular form of mixing component relating to each agent's wealth. We also demonstrate that wealth accumulation for logarithmic and other isoelastic agents (through payoffs on prediction of training targets) can implement both Bayesian model updates and mixture weight updates by imposing different market payoff structures. An iterative algorithm is given for market equilibrium computation. We demonstrate that inhomogeneous markets of agents with isoelastic utilities outperform state of the art aggregate classifiers such as random forests, as well as single classifiers (neural networks, decision trees) on a number of machine learning benchmarks, and show that isoelastic combination methods are generally better than their logarithmic counterparts.Comment: Appears in Proceedings of the 29th International Conference on Machine Learning (ICML 2012

This Could Have Been an Email: Adapting English Language Arts Curriculum to Better Suit Modern Communication Needs

As technology and society evolve, so do the modes and practices of communication. The teacher resources and classroom activities presented within this capstone project focus on the combination of Minnesota’s English Language Arts (ELA) and College and Career Readiness (CCR) standards to develop future-ready classroom curricula and activities. Through the creation of an asynchronous professional resource for educators, this project works to highlight key tenets of modern communication, skills students will need in their futures, and showcase how these skills can look in the classroom. With research focusing on academic standards, employability skills, and classroom curriculum and instruction, the goal of this work is to empower educators to review their own classroom practices and how they are serving students, as well as present tangible resources educators can bring to their own practice. While designed specifically for secondary ELA classrooms in Minnesota, the resources and concepts presented could be adapted to many educational settings

Reading to Learn: A literature review within a South African context

Academic literacy development within the secondary schooling system in South Africa has reached crisis proportions, with a large number of students exiting the system unable to function adequately within the tertiary sector or labour market. Attempts to remedy this crisis by introducing curriculum reform over the past few years have yielded little success, with universities having to take on the literacy problem by offering a variety of remedial programmes to ensure that students are equipped to access learning and succeed at their studies. Research shows that most literacy intervention programs at universities appear to favour a more traditional approach to English academic language development by focusing on grammatical rules, sentence structure, spelling and punctuation. This bottom-up approach does not necessarily equip students with the skills needed to write coherent and cohesive extended pieces of writing as required by university assessment processes. For this reason, the Reading to Learn (RtL) methodology was chosen to be implemented within a writing module at the University of KwaZulu-Natal and within selected Grade 11 classes in the Winelands District in an attempt to find an alternative approach to academic literacy development. The purpose of this article is to offer a comprehensive synthesis of some of the theoretical assumptions of RtL as well as its practical implementation before embarking on an evaluative study of this methodology in future papers. In doing so, this article offers a brief discussion on academic literacy pedagogies and situates RtL within these frameworks. This is followed by a synthesis of the practical implementation of RtL and a discussion of the works of Halliday (1989, 1996), Vygotsky (1978) and Bernstein (1990, 1996) which have had an influence on the development of RtL.Keywords: academic literacy, Reading to Learn, academic reading and writing pedagogies, genre pedagogy, scaffolded learnin

Education spending, economic development, and the size of government

We examine the association between economic development and two measures of public spending on education: the “national effort” (public spending on education as a proportion of GDP) and “budget share” (public spending on education as a proportion of total government spending). Using panel data for a large sample of countries from 1989 to 2015, we compare mean levels of national effort and budget share measures for economically and politically distinct groups of countries. We find that economically more developed (richer) countries are characterised by a higher national effort and a lower budget share than less economically developed countries. This implies that richer countries, on average, have larger public sectors than poorer countries, consistent with Wagner’s law and Baumol’s “cost disease” hypothesis

Verification of stereotactic radiotherapy

Investigations have been made into the use of a computer based simulation technique (Monte Carlo (MC)) to ionising radiation transport in order to verify the doses delivered during linear accelerator based stereotactic radiotherapy and radiosurgery. Due to the complex nature of the micro multi-leaf collimators (μMLC) used in this these treatments, a bespoke model of the μMLC was developed and combined with standard component modules to represent the remainder of the linear accelerator. Following validation of the above models, investigations were made into the dosimetry of small fields, defined by the μMLC and measured with a variety of detectors. Comparisons of relative output, profiles and depth doses were made against MC simulations, and a series of correction factors determined, to account for detector geometry and the non water equivalence of materials used in semiconductor detectors. An assessment was then made to determine the smallest fields that can be measured with each detector with confidence. Systems were then developed to independently simulate stereotactic treatments and compare doses simulated with those calculated by the treatment planning system (TPS); excellent agreement between TPS calculations and MC simulations was observed. The application of MC methods to determine the most appropriate treatment tactics and calculation algorithms for stereotactic body radiotherapy in the lung was then investigated with recommendations made on the most appropriate calculation algorithms and beam arrangements for the technique. The doses calculated using the type-b or collapsed cone algorithm agreed most closely with the MC simulation. There was little difference observed between plans using more than four beams in the treatment delivery. Treatment techniques using only three beams or less achieved poorer coverage of the tumour with dose, producing lower doses at the periphery of the tumour near the interface with the surrounding lung tissue, compared to using a greater number of beams. Finally, methods of transit dosimetry using Electronic Portal Imaging Devices were investigated for use in cranial stereotactic radiotherapy. Three methods were investigated based on a full MC simulation of the radiation transport through the patient and on to the imager, prediction of the dose based on a TPS calculation and an approximation of the radiological path length of the central axis of the beams to derive an expected dose at the imager plane. The MC method produced the best agreement at the expense of a longer time to acquire the comparison doses compared to the TPS calculation method. The equivalent path length method showed good agreement (within 3.5%) between delivered and predicted doses but at a single point.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

DNA looping by two-site restriction endonucleases: heterogeneous probability distributions for loop size and unbinding force

Proteins interacting at multiple sites on DNA via looping play an important role in many fundamental biochemical processes. Restriction endonucleases that must bind at two recognition sites for efficient activity are a useful model system for studying such interactions. Here we used single DNA manipulation to study sixteen known or suspected two-site endonucleases. In eleven cases (BpmI, BsgI, BspMI, Cfr10I, Eco57I, EcoRII, FokI, HpaII, NarI, Sau3AI and SgrAI) we found that substitution of Ca(2+) for Mg(2+) blocked cleavage and enabled us to observe stable DNA looping. Forced disruption of these loops allowed us to measure the frequency of looping and probability distributions for loop size and unbinding force for each enzyme. In four cases we observed bimodal unbinding force distributions, indicating conformational heterogeneity and/or complex binding energy landscapes. Measured unlooping events ranged in size from 7 to 7500 bp and the most probable size ranged from less than 75 bp to nearly 500 bp, depending on the enzyme. In most cases the size distributions were in much closer agreement with theoretical models that postulate sharp DNA kinking than with classical models of DNA elasticity. Our findings indicate that DNA looping is highly variable depending on the specific protein and does not depend solely on the mechanical properties of DNA