Conical refraction healing after partially blocking the input beam

In conical refraction, when a focused Gaussian beam passes along one of the optic axes of a biaxial crystal, it is transformed into a pair of concentric bright rings at the focal plane. We demonstrate both theoretically and experimentally that this transformation is hardly affected by partially blocking the Gaussian input beam with an obstacle. We analyze the influence of the size of the obstruction both on the transverse intensity pattern of the beam and on its state of polarization, which is shown to be very robust.

Optimization of adaptive traffic signal control with transit signal priority at isolated intersections using parallel genetic algorithms

Optimization of adaptive traffic signal timing is one of the most complex problems in traffic control systems. This dissertation presents a new method that applies the parallel genetic algorithm (PGA) to optimize adaptive traffic signal control in the presence of transit signal priority (TSP). The method can optimize the phase plan, cycle length, and green splits at isolated intersections with consideration for the performance of both the transit and the general vehicles. Unlike the simple genetic algorithm (GA), PGA can provide better and faster solutions needed for real-time optimization of adaptive traffic signal control. ^ An important component in the proposed method involves the development of a microscopic delay estimation model that was designed specifically to optimize adaptive traffic signal with TSP. Macroscopic delay models such as the Highway Capacity Manual (HCM) delay model are unable to accurately consider the effect of phase combination and phase sequence in delay calculations. In addition, because the number of phases and the phase sequence of adaptive traffic signal may vary from cycle to cycle, the phase splits cannot be optimized when the phase sequence is also a decision variable. A "flex-phase" concept was introduced in the proposed microscopic delay estimation model to overcome these limitations. ^ The performance of PGA was first evaluated against the simple GA. The results show that PGA achieved both faster convergence and lower delay for both under- or over-saturated traffic conditions. A VISSIM simulation testbed was then developed to evaluate the performance of the proposed PGA-based adaptive traffic signal control with TSP. The simulation results show that the PGA-based optimizer for adaptive TSP outperformed the fully actuated NEMA control in all test cases. The results also show that the PGA-based optimizer was able to produce TSP timing plans that benefit the transit vehicles while minimizing the impact of TSP on the general vehicles. The VISSIM testbed developed in this research provides a powerful tool to design and evaluate different TSP strategies under both actuated and adaptive signal control. ^

Florencio Gelabert Intersections

Published on the occasion of an exhibition held at Frost Art Museum. Essay by Francine Birbragher.

On the dual-cone nature of the conical refraction phenomenon

In conical refraction (CR), a focused Gaussian input beam passing through a biaxial crystal and parallel to one of the optic axes is transformed into a pair of concentric bright rings split by a dark (Poggendorff) ring at the focal plane. Here, we show the generation of a CR transverse pattern that does not present the Poggendorff fine splitting at the focal plane, i.e., it forms a single light ring. This light ring is generated from a nonhomogeneously polarized input light beam obtained by using a spatially inhomogeneous polarizer that mimics the characteristic CR polarization distribution. This polarizer allows modulating the relative intensity between the two CR light cones in accordance with the recently proposed dual-cone model of the CR phenomenon. We show that the absence of interfering rings at the focal plane is caused by the selection of one of the two CR cones. (C) 2015 Optical Society of America

Polarization tailored novel vector beams based on conical refraction

Coherent vector beams with involved states of polarization (SOP) are widespread in the literature, having applications in laser processing, super-resolution imaging and particle trapping. We report novel vector beams obtained by transforming a Gaussian beam passing through a biaxial crystal, by means of the conical refraction phenomenon. We analyze both experimentally and theoretically the SOP of the different vector beams generated and demonstrate that the SOP of the input beam can be used to control both the shape and the SOP of the transformed beam. We also identify polarization singularities of such beams for the first time and demonstrate their control by the SOP of the input beam.

Conical refraction with low-coherent light sources

We report on conical refraction (CR) experiments with low-coherent light sources such as light-emitting diodes (LEDs) that demonstrated different CR patterns. The change of a pinhole size from 25 to 100 μm reduced the spatial coherence of the LED radiation and resulted in the disappearance of the dark Poggendorf ring in the Lloyd's plane. This is attributed to the interference nature of the Lloyd's distribution and is found to be in excellent agreement with the paraxial dual-cone model of CR.

Aspects of Motives: Finite-dimensionality, Chow-Kunneth Decompositions and Intersections of Cycles

This thesis analyzes the Chow motives of 3 types of smooth projective varieties: the desingularized elliptic self fiber product, the Fano surface of lines on a cubic threefold and an ample hypersurface of an Abelian variety. For the desingularized elliptic self fiber product, we use an isotypic decomposition of the motive to deduce the Murre conjectures. We also prove a result about the intersection product. For the Fano surface of lines, we prove the finite-dimensionality of the Chow motive. Finally, we prove that an ample hypersurface on an Abelian variety possesses a Chow-Kunneth decomposition for which a motivic version of the Lefschetz hyperplane theorem holds.

Intersections: proceedings of the youth work and music education symposium

The ‘Intersections: Youth Work and Music Education’ Symposium took place on Friday, 27th June 2014 in University College Cork. This event, held in association with the Institute of Social Sciences in the 21st Century (ISS21), was made possible thanks to funding from UCC’s Strategic Research Fund. The principle aim of this seed funding is to generate new research interests and this presented the ideal opportunity for developing collaborative relationships between youth work and music education lecturers, researchers and practitioners across the island of Ireland. This led to the formation of a new ‘Intersections’ research cluster, comprising representatives from four third-level institutions, each of which offers both youth work and music education undergraduate and/or postgraduate programmes, namely: University College Cork; National University of Ireland, Maynooth; Dundalk Institute of Technology; and, University of Ulster. This document presents some preliminary findings from primary research conducted through each of the participating institutions in their local areas. Data was also collected during the symposium, through engaging in small group discussions populated by the event’s participants. The publication and dissemination of this document was included in the original Strategic Research Fund proposal. Its intended audience includes youth workers, music educators, community-based practitioners, policy-makers and academics who are motivated and enthused by the possibilities of music-oriented youth work in Ireland and beyond.

Drawing in Duos: The Journeys and Intersections Collaboration Project Between Istanbul and Worcester

This paper focuses on a collaborative drawing project carried out between two undergraduate drawing courses, one in İstanbul and the other in Worcester, during the Fall 2015 semester. Duos -teams of two working remotely- took turns to work on the same drawing in correspondence for three months by means of communication and sharing the changing images on-line with one another. The project introduced a collaborative method of learning based on drawing, initiated cultural exchange and cooperation. The role of drawing in the project was critical due to the direct but gradual nature of transmitting meaning onto paper. Outcomes of this project consisted of a flexible and playful creation process for students making use of the element of chance. They sought alternate ways to finalize a drawing and experienced the benefits of artistic co-production. The project has the capacity to inspire artists, instructors and others interested in creative partnership in different disciplines and can be of value as an educational model.

Exploring the intersections of creative and academic life among Australian academic creative writing practitioners

Intersections of Gay and Bisexual Identity with Fatness

This thesis examines the intersections of gay and bisexual identity with body size, or fatness. Gay and bisexual identity and fatness are marginalized social identities that seem to be incompatible (Bond, 2013). While a sense of collective identity with the gay and bisexual community has been shown to be a protective factor against internalized homonegativity in gay and bisexual men (Halpin & Allen, 2004), the degree to which this protective factor persists for fat people in an anti-fat environment like the gay and bisexual community (Wrench & Knapp, 2008) has not been explored. This intersection of identities and anti-fat culture seemed to suggest there might be a relationship between fatness and internalized homophobia. Fatness did not moderate the relationship between sense of belonging to the gay and bisexual community and internalized homonegativity, but a significant positive relationship was found between belongingness to the gay and bisexual community and body shame.

Intersections: Music, Words, and Pictures Robin McCabe, host December 4, 2016

Concert Program

Gender and the Australian parliament

This dissertation by publication which focuses on gender and the Australian federal parliament has resulted in the submission of three refereed journal articles. Data for the study were obtained from 30 semi-structured interviews undertaken in 2006 with fifteen (15) male and fifteen (15) female members of the Australian parliament. The first of the articles is methodological and has been accepted for publication in the Australian Journal of Political Science. The paper argues that feminist political science is guided by five important principles. These are placing gender at the centre of the research, giving emphasis to women’s voice, challenging the public/private divide, using research to transform society and taking a reflexive approach to positionality. It is the latter principle, that of the importance of taking a reflexive approach to research which I explore in the paper. Through drawing on my own experiences as a member of the House of Representatives (Forde 1987-1996) I reflexively investigate the intersections between my background and my identity as a researcher. The second of the articles views the data through the lens of Acker’s (1990) notion of the ‘gendered organization’ which posits that there are four dimensions by which organizations are gendered. These are via the division of labour, through symbols, images and ideologies, by workplace interactions and through the gendered components of individual identity. In this paper which has been submitted to the British Journal of Political Science, each of Acker’s (1990) dimensions is examined in terms of the data from interviews with male and female politicians. The central question investigated is thus to what extent does the Australian parliament conform to Acker’s (1990) concept of the ‘gendered organization’? The third of the papers focuses specifically on data from interviews with the 15 male politicians and investigates how they view gender equality and the Australian parliament. The article, which has been submitted to the European Journal of Political Science asks to what extent contemporary male politicians view the Australian parliament as gendered? Discourse analysis that is ‘ways of viewing’ (Bacchi, 1999, p. 40) is used as an approach to analyse the data. Three discursive frameworks by which male politicians view gender in the Australian parliament are identified. These are: that the parliament is gendered as masculine but this is unavoidable; that the parliament is gendered as feminine and women are actually advantaged; and that the parliament is gender neutral and gender is irrelevant. It is argued that collectively these framing devices operate to mask the many constraints which exist to marginalise women from political participation and undermine attempts to address women’s political disadvantage as political participants. The article concludes by highlighting the significance of the paper beyond the Australian context and calling for further research which names and critiques political men and their discourses on gender and parliamentary practices and processes.

AITPM Email Newsletter Volume 0905, May 2009: Presidents Message

President’s Message Hello fellow AITPM members, We’ve been offered a lot of press lately about the Federal Government’s plan for the multibillion dollar rollout of its high speed broadband network, which at the moment is being rated to a speed of 100Mb/s. This seems fantastic in comparison to the not atypical 250 to 500kb/s that I receive on my metropolitan cable broadband, which incidentally my service provider rates at theoretical speeds of up to 8 Mb/s. I have no doubt that such a scheme will generate significant advantages to business and consumers. However, I also have some reservations. Only a few of years ago I marvelled at my first 256Mb USB stick, which cost my employer about $90. Last month I purchased a 16Gb stick with a free computer carry bag for $80, which on the back of my envelope has given me about 72 times the value of my first USB stick not including the carry bag! I am pretty sure the technology industry will find a way to eventually push a lot more than 100Mb/s down the optic fibre network just as they have done with pushing several Mb/s ADSL2 down antique copper wire. This makes me wonder about the general problem of inbuilt obsolescence of all things high-tech due to rapid advances in the tech industry. As a transport professional I then think to myself that our industry has been moving forward at somewhat of a slower pace. We certainly have had major milestones having significant impacts, such as the move from horse and cart to the self propelled motor vehicle, sealing and formal geometric design of roads, development of motorways, signalisation of intersections, coordination of networks, to simulation modelling for real time adaptive control (perhaps major change has been at a frequency of 30 years or so?). But now with ITS truly penetrating the transport market, largely thanks to the in-car GPS navigator, smart phone, e-toll and e-ticket, I believe that to avoid our own obsolescence we’re going to need to “plan for ITS” rather than just what we seem to have been doing up until now, that is, to get it out there. And we’ll likely need to do it at a faster pace. It will involve understanding how to data mine enormous data sets, better understanding the human/machine interface, keeping pace with automotive technology more closely, resolving the ethical and privacy chestnuts, and in the main actually planning for ITS to make peoples’ lives easier rather than harder. And in amongst this we’ll need to keep pace with the types of technology advances similar to my USB stick example above. All the while we’ll be making a brand new set of friends in the disciplines that will morph into ITS along with us. Hopefully these will all be “good” problems for our profession to have. I should close in reminding everyone again that AITPM’s flagship event, the 2009 AITPM National Conference, Traffic Beyond Tomorrow, is being held in Adelaide from 5 to 7 August. www.aitpm.com has all of the details about how to register, sponsor a booth, session, etc. Best regards all, Jon Bunker