Verifying anonymity in voting systems using CSP

We present formal definitions of anonymity properties for voting protocols using the process algebra CSP. We analyse a number of anonymity definitions, and give formal definitions for strong and weak anonymity, highlighting the difference between these definitions. We show that the strong anonymity definition is too strong for practical purposes; the weak anonymity definition, however, turns out to be ideal for analysing voting systems. Two case studies are presented to demonstrate the usefulness of the formal definitions: a conventional voting system, and Prêt à Voter, a paper-based, voter-verifiable scheme. In each case, we give a CSP model of the system, and analyse it against our anonymity definitions by specification checks using the Failures-Divergences Refinement (FDR2) model checker. We give a detailed discussion on the results from the analysis, emphasizing the assumptions that we made in our model as well as the challenges in modelling electronic voting systems using CSP.     

Cyclic voltammetry of monel 400 in lithium hydroxide solution at elevated temperatures

The electrochemistry of Monel 400 in 1 mole/kg^?1 LiOH solution at 25, 125 and 250°C has been investigated using the technique of cyclic voltammetry. The general electrochemical behaviour is found to most closely approximate to that of the major component, nickel, although expansion of the current scale reveals anodic and cathodic peaks which probably arise from redox processes involving copper. The general similarity to nickel can be rationalized in terms of either the d electron theory for cupronickel alloys or phase separation, the latter being favoured in the present study. At 25°C the majority of charge consumed on sweeping the potential in the positive direction is involved in the formation of an oxide film at potentials close to oxygen evolution. This process is no longer observed at 250°C, due to a sharp reduction in the oxygen evolution overpotential with temperature. The majority of charge consumed on cyclic sweeping at this temperature is attributed to active dissolution of the nickel component of the alloy to form HNiO^?₂ (or Ni(OH)^?₂ (or Ni(OH)^?₃) at potentials slightly positive to the hydrogen evolution region.     

Systemic Induction of Allelochemicals in Glanded and Glandless Isogenic Cotton by Spodoptera exigua Feeding

Induction of systemic resistance to feeding of beet armyworm, Spodoptera exigua, was investigated in two isogenic lines of Stoneville 213 cotton, Gossypium hirsutum, that differed in the presence of pigment glands. In laboratory bioassays, larvae strongly preferred to feed on glandless cotton plants when presented a choice between undamaged terminal leaves of undamaged glanded and glandless plants. Feeding damage inflicted by S. exigua larvae on the two oldest leaves of glanded plants seven days prior to feeding bioassays caused larvae to prefer by 33-fold the undamaged terminal foliage from undamaged plants compared to that from damaged plants. Feeding damage on glandless plants caused only a 2.6-fold greater preference for terminal foliage from undamaged plants over foliage from previously damaged plants. Extracts of terminal foliage from glanded cotton damaged seven days earlier had significantly greater quantities of terpenoid aldehydes (hemigossypolone, gossypol, and heliocides) than did foliage from undamaged glanded plants. Terpenoid aldehydes were undetectable in extracts of both undamaged and previously damaged glandless plants. The profile of volatile compounds collected from the headspace of mechanically damaged terminal leaves of undamaged glanded and glandless plants differed. Both cotton isolines released large quantities of lipoxygenase products (hexenyl alcohols, acetates, and butyrates), but glandless plants released only small amounts of mono- and sesquiterpenes compared to glanded plants. Glandless plants damaged seven days prior to volatile collection released significantly greater quantities of lipoxygenase products, -ocimene, and - and -farnesene than did undamaged glandless plants. Previously damaged glanded plants released significantly greater quantities of all mono- and sesquiterpenes and hexenyl acetates and butyrates, but not alcohols. The relative importance of volatile compounds versus terpenoid aldehydes in induced feeding deterrence in cotton to S. exigua larvae is still unclear.     

A versatile facility for laboratory studies of viscoelastic and poroelastic behaviour of rocks

Novel laboratory equipment has been modified to allow both torsional and flexural oscillation measurements at sub-microstrain amplitudes, thereby providing seismic-frequency constraints on both the shear and compressional wave properties of cylindrical rock specimens within the linear regime. The new flexural mode capability has been tested on experimental assemblies containing fused silica control specimens. Close consistency between the experimental data and the results of numerical modelling with both finite-difference and finite-element methods demonstrates the viability of the new technique. The capability to perform such measurements under conditions of independently controlled confining and pore-fluid pressure, with emerging strategies for distinguishing between local (squirt) and global (specimen-wide) fluid flow, will have particular application to the study of frequency-dependent seismic properties expected of cracked and fluid-saturated rocks of the Earth's upper crust.     

Autobiographical Accounts of Students' Experiences Learning Mathematics: A Review

ABSTRACT

In this article, we review published literature that draws on autobiographical accounts of students' experiences learning mathematics. We summarize the main findings of the target literature and present recommendations for further research that will extend this field. Our review indicates that autobiographical and narrative methodological approaches have the potential to occasion important advances in our knowledge of students' experiences learning mathematics. However, relative to accounts of preservice teacher learning, there is a paucity of published research that documents the mathematics learning experiences of kindergarten to Grade 12 students.     

Mediating Power: Distance Learning Interfaces, Classroom Epistemology, and the Gaze

Distance learning's interfaces—from corresponding through the postal service to the televised talking head—have traditionally been designed from the top down, supporting banking models of learning or, in writing instruction, current-traditional rhetoric pedagogies. Due to temporal and spatial constraints, these interface designs often support (or encourage) one-way communication from the instructor to the student. Students mostly interact with the instructor by asking questions or submitting work, and they tend to have little correspondence with other peers. These methods clearly privilege the instructor's knowledge and evaluation. Furthermore, these interface designs empower the instructor to gaze upon the students and assess them—often not as a corporeal body but as a corpus of texts. Thus, each interface adopted for distance learning sets up a power dynamic in which the capability to share the roles of creating knowledge is juxtaposed with the instructor's capability to normalize the students and reify their own authority through their gaze. In this article we examine the traditional classroom interface through the correspondence course interface, the simulated classroom interface, and the synchronous video interface to raise questions about the infrastructures of distance learning and their implications for student learning.