On A. D. Smith's constancy based defence of direct realism

This paper presents an argument against A D Smith's Direct Realist theory of perception, which attempts to defend Direct Realism against the argument from illusion by appealing to conscious perceptual states that are structured by the perceptual constancies. Smith's contention is that the immediate objects of perceptual awareness are characterised by these constancies, which removes any difficulty there may be in identifying them with the external, or normal, objects of awareness. It is here argued that Smith's theory does not provide an adequate defence of Direct Realism because it does not adequately deal with the difficulties posed by the possibility of perceptual illusion. It is argued that there remain possible illusory experiences where the immediate objects of awareness, which in Smith's account are those characterised by perceptual constancies, cannot be identified with the external objects of awareness, contrary to Direct Realism. A further argument is offered to extend this conclusion to all non-illusory cases, by adapting an argument of Smith's own for the generalising step of the Argument from Illusion. The result is that Smith's theory does not provide an adequate Direct Realist account of the possibility of perceptual illusion. © 2011 Springer Science+Business Media B.V

Formalising extended finite state machine transition merging

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this recordModel inference from system traces, e.g. for analysing legacy components or generating security tests for distributed components, is a common problem. Extended Finite State Machine (EFSM) models, managing an internal data state as a set of registers, are particularly well suited for capturing the behaviour of stateful components however existing inference techniques for (E)FSMs lack the ability to infer the internal state and its update functions. In this paper, we present the underpinning formalism for an EFSM inference technique that involves the merging of transitions with updates to the internal data state. Our model is formalised in Isabelle/HOL, allowing for the machine-checked validation of transition merges and system properties

A model of emulation funds

© 2014 AFAANZ. Emulation funds are a potentially cost-effective way for multimanager funds to improve their investment performance by delaying and netting trade signals from underlying managers. We develop a model to represent the expected sources of differential performance in an emulation fund relative to its underlying multimanager portfolio. The model formalises the expected interaction between potential savings and opportunity costs and allows us to observe complexities in the emulation process that are hidden without a benchmark. Finally, the functional representation of the model allows sensitivity analysis of the emulation fund to key parameters and enables us to determine theoretically optimal lag periods

A Formal Model of Extended Finite State Machines

This is the final version. Available from AFP via the link in this recordIn this AFP entry, we provide a formalisation of extended finite state machines (EFSMs) where models are represented as finite sets of transitions between states. EFSMs execute traces to produce observable outputs. We also define various simulation and equality metrics for EFSMs in terms of traces and prove their strengths in relation to each other. Another key contribution is a framework of function definitions such that LTL properties can be phrased over EFSMs. Finally, we provide a simple example case study in the form of a drinks machine

Inference of Extended Finite State Machines

This is the final version. Available from AFP via the link in this recordIn this AFP entry, we provide a formal implementation of a state-merging technique to infer extended finite state machines (EFSMs), complete with output and update functions, from black-box traces. In particular, we define the subsumption in context relation as a means of determining whether one transition is able to account for the behaviour of another. Building on this, we define the direct subsumption relation, which lifts the subsumption in context relation to EFSM level such that we can use it to determine whether it is safe to merge a given pair of transitions. Key proofs include the conditions necessary for subsumption to occur and that subsumption and direct subsumption are preorder relations. We also provide a number of different heuristics which can be used to abstract away concrete values into registers so that more states and transitions can be merged and provide proofs of the various conditions which must hold for these abstractions to subsume their ungeneralised counterparts. A Code Generator setup to create executable Scala code is also defined

Incorporating Data into EFSM Inference

This is the author accepted manuscript. The final version is available from Springer Verlag via the DOI in this record17th International Conference, SEFM 2019 Oslo, Norway, September 18–20, 2019Models are an important way of understanding software systems. If they do not already exist, then we need to infer them from system behaviour. Most current approaches infer classical FSM models that do not consider data, thus limiting applicability. EFSMs provide a way to concisely model systems with an internal state but existing inference techniques either do not infer models which allow outputs to be computed from inputs, or rely heavily on comprehensive white-box traces that reveal the internal program state, which are often unavailable. In this paper, we present an approach for inferring EFSM models, including functions that modify the internal state. Our technique uses black-box traces which only contain information visible to an external observer of the system. We implemented our approach as a prototype

Curriculum Infusion Through Case Studies: Engaging Undergraduate Students In Course Subject Material and Influencing Behavior Change

This study investigated infusing health promotion topics into an engineering course via problem-based case studies and lecture to assess student learning and self-reported behavior. Junior-level systems engineering students in two sections participated: one section with 52 students and one with 36. One section received a celebratory drinking case; one received distracted driving case and a lecture about hazardous drinking. Student ability ratings related to the course subject matter generally improved with both cases. The lecture appeared to enhance health promotion knowledge. Students self-reported behavior change with both cases. Case studies as a form of curriculum infusion for health promotion topics show promise. The use of case studies overall was well-received by students and coupled with lecture material can increase student health promotion knowledge and behavior change

How has the Relevance of Institutional Brokerage Changed?

© 2016 International Review of Finance Ltd. 2016 Institutional brokerage rates have been in decline. We investigate whether this reduction has coincided with a fall in benefits provided by brokers to institutional asset managers. We use trade packages from both active and passive equity funds from 1995 to 2001 and active equity funds from 2002 to 2010. We find that later period active funds recoup a combined 1.75 basis point benefit (from price impact cost recovery and short-term alpha) per basis point of brokerage cost. Later period active investors saw improved trade price impact and shorter-term alpha net benefits, relative to earlier period active investors. These results are robust after controlling for trade characteristics and cross-sectional variation over time. Our findings suggest that brokers innovate to provide valuable services in the subsequent, lower brokerage environment

Photometric Properties of Void Galaxies in the Sloan Digital Sky Survey DR7 Data Release

Using the sample presented in Pan:2011, we analyse the photometric properties of 88,794 void galaxies and compare them to galaxies in higher density environments with the same absolute magnitude distribution. In Pan et al. (2011), we found a total of 1054 dynamically distinct voids in the SDSS with radius larger than 10h^-1 Mpc. The voids are underdense, with delta rho/rho < -0.9 in their centers. Here we study the photometric properties of these void galaxies. We look at the u - r colours as an indication of star formation activity and the inverse concentration index as an indication of galaxy type. We find that void galaxies are statistically bluer than galaxies found in higher density environments with the same magnitude distribution. We examine the colours of the galaxies as a function of magnitude, and we fit each colour distribution with a double-Gaussian model for the red and blue subpopulations. As we move from bright to dwarf galaxies, the population of red galaxies steadily decreases and the fraction of blue galaxies increases in both voids and walls, however the fraction of blue galaxies in the voids is always higher and bluer than in the walls. We also split the void and wall galaxies into samples depending on galaxy type. We find that late type void galaxies are bluer than late type wall galaxies and the same holds for early galaxies. We also find that early type, dwarf void galaxies are blue in colour. We also study the properties of void galaxies as a function of their distance from the center of the void. We find very little variation in the properties, such as magnitude, colour and type, of void galaxies as a function of their location in the void. The only exception is that the dwarf void galaxies may live closer to the center. The centers of voids have very similar density contrast and hence all void galaxies live in very similar density environments (ABRIDGED)Comment: 10 pages, 25 figure