Fidelity and complexity : aspects of reality in interactive learning environments for physics learners

Computer-based interactive learning environments in physics can help students to differentiate between their intuitive views on natural phenomena and the formalisms of Newtonian physics. This thesis describes empirical investigations of a specific type of interactive learning environments, computer-based simulations. In many cases computer simulations deal with a simplified and idealised version of the natural phenomenon. Presenting the user with a simplification of reality is seen as one of the advantages of simulations, since too complex and too realistic simulations may sometimes be overwhelming for learners and may not permit the identification of the underlying model. Yet implications arise about the degree to which students either expect or perceive simulations to be real and how these expectations and perceptions affect their interaction with the simulation.Reality for the purposes of this research is considered to be a construct comprising the visual fidelity (fidelity) and the complexity of the underlying physical model (complexity) of the simulation. Evaluation of a number of simulations, two case studies and interviews with simulation designers and educators suggested these components. Altering the relation between fidelity and complexity levels affects students' learning and contributes to the students' perception of reality. This is demonstrated in a study of a number of simulations of the same physical phenomenon (Newtonian collisions) with degrees of fidelity and complexity which have been examined to test this hypothesis. Two empirical studies were then conducted to investigate the use of simulations which represented different fidelity and complexity levels.Analyses were carried out on videotapes and questionnaires of students interacting collaboratively with the simulations (40 hours of computer based activity). The empirical approaches to these studies, reports on work done, including the emerging data in multiple forms (questionnaires, video and audio tapes of the students interaction) and its analysis are presented in this thesis. The work reported looks at students' interaction with the simulations (pre to post test learning gain and issues concerning pre and post testing), their comments on the interface and the model underlying the simulation.The thesis supports the view that well designed computer-based simulations can promote learning and that design issues are essential to the creation of successful simulations. The findings claim that: a) enhanced fidelity of an instructional simulation has positive effects on the learner outcome,b) interfaces which use multiple representations offer valuable information which facilitates problem solving strategies andc) low complexity simulations are better suited to novice learners.These outcomes are presented as implications for simulation design and the use and development of a syntax in simulation design is also discussed (design criteria for how systems might be built). Finally the outcomes' applicability, the limitations of the studies, as well as the scope for further research that should lead to an understanding of the factors which promote successful use of simulations in the teaching of physics are presented

Expected performance of the ATLAS experiment - detector, trigger and physics

A detailed study is presented of the expected performance of the ATLAS detector. The reconstruction of tracks, leptons, photons, missing energy and jets is investigated, together with the performance of b-tagging and the trigger. The physics potential for a variety of interesting physics processes, within the Standard Model and beyond, is examined. The study comprises a series of notes based on simulations of the detector and physics processes, with particular emphasis given to the data expected from the first years of operation of the LHC at CERN

Partial-wave analysis of the radiative decay of J/psi into p pbar

The Standard Model describes the smallest building blocks of our universe, so-called quarks and leptons, and the forces that act on them. The building blocks can bundle into larger and heavier particles. These composite particles are called hadrons. One of the best-known hadrons is the proton. The Higgs boson, which was first detected in 2012, explains how the smallest building blocks get their mass. However, the Higgs mechanism only explains 1% of the mass of the proton. The other 99% arises from internal strong forces that are not yet well-understood. To better understand the 99%, it is important to study the production of hadrons in different processes, and to obtain information from as many different decay reactions as possible. Hadrons of the charmonia group, such as J/psi and the ground state eta_c, are highly suitable particles for this, and result in a relatively easy-to-interpret spectrum of narrow peaks that do not overlap. In this thesis the radiative decay of J/psi into a proton (p) and antiproton (pbar) is studied. The aim of this study was to gain a better understanding of the full spectrum of the proton-antiproton invariant mass, and especially to gain more insight into the poorly-understood properties of the intermediate resonance eta_c. In this study, a special multidimensional analysis, a so-called partial-wave analysis, was applied for the first time to the radiative decay from J/psi to eta_c. This study is based on data taken by the Beijing Spectrometer (BES) III, which has collected world's largest dataset of J/psi reactions

Opinions and Preferences as Socially Distributed Attitudes

The dissertation focuses on how to best represent the consensus and attitude dynamic of a group given the attitudes of its individuals. This is done in the Bayesian epistemology framework using pooling with imprecise probabilities, and in utility theory extending Harsanyi's aggregation theorem to characterize other directed attitudes like spite and altruism. The final part of the dissertation considers attitudes within social networks and provides explanations and simulation models for online segregation and tribalism as well as the spread of rumors through contagion. The dissertation hopes to contribute to foundational issues like that of epistemic consensus, but also to new emerging phenomena in social epistemology

Measuring R(D(*)) for B → ‾D(*)τν_τ using Semileptonic Tags and Tau Decays to Hadrons

We perform a measurement of R(D(*)) for B → D(*)τντ using semileptonic tagging and τ decays to hadrons on the 429 fb-1 of data that BABAR collected at the Υ(4S) resonance. This is the first measurement of R(D(*)) using the specied reconstruction channels. Candidate selection was performed with supervised learning, where the training labels were obtained by solving an instance of subgraph isomorphism. The signal extraction was performed by solving an optimization problem whose objective function required the evaluation of kernel density estimates that were accelerated by a branch-and-bound algorithm as well as with a GPU. The training data for the density estimates were themselves the output of two classier scores. We present a 68% and 95% confidence regions of R(D(*)), which do not show enough evidence to reject the standard model prediction.</p

WHEN BATTERED PERSONS KILL: THE IMPACT OF GENDER STEREOTYPES ON MOCK JUROR PERCEPTIONS

The present experiment investigated the role of gender stereotypes in cases in which a battered person kills his or her abuser. Regression analysis revealed an overall gender bias such that mock jurors were more likely to convict a man defendant who had killed his abusive wife than they were when a woman defendant who had killed her husband. Mediational analyses indicated that the relationship between abuser gender and verdict was partially mediated by sympathy toward the victim, and fully mediated by sympathy toward the defendant. Regression analysis also revealed an effect of abuser height, such that conviction rates were higher when an abuser was taller than his or her partner, regardless of abuser gender. Though not significant, trends suggested the act of killing an abusive partner was perceived as a protective act toward the child. Overall, the present study provides evidence that gender biases exist in cases in which a battered person kills his or her abuser