aa-cell in practice : an approach to musical live coding

Live coding performances provide a context with particular demands and limitations for music making. In this paper we discuss how as the live coding duo aa-cell we have responded to these challenges, and what this experience has revealed about the computational representation of music and approaches to interactive computer music performance. In particular we have identified several effective and efficient processes that underpin our practice including probability, linearity, periodicity, set theory, and recursion and describe how these are applied and combined to build sophisticated musical structures. In addition, we outline aspects of our performance practice that respond to the improvisational, collaborative and communicative requirements of musical live coding.

Uncertainties that matter : risk, response-ability, ethics and the moment of exchange in Live Art

This article examines the moment of exchange between artist, audience and culture in Live Art. Drawing on historical and contemporary examples, including examples from the Exist in 08 Live Art Event in Brisbane, Australia, in October 2008, it argues that Live Art - be it body art, activist art, site-specific performance, or other sorts of performative intervention in the public sphere - is characterised by a common set of claims about activating audiences, asking them to reflect on cultural norms challenged in the work. Live Art presents risky actions, in a context that blurs the boundaries between art and reality, to position audients as ‘witnesses’ who are personally implicated in, and responsible for, the actions unfolding before them. This article problematises assumptions about the way the uncertainties embedded in the Live Art encounter contribute to its deconstructive agenda. It uses the ethical theory of Emmanuel Levinas, Hans-Thies Lehmann and Dwight Conquergood to examine the mechanics of reductive, culturally-recuperative readings that can limit the efficacy of the Live Art encounter. It argues that, though ‘witnessing’ in Live Art depends on a relation to the real - real people, taking real risks, in real places - if it fails to foreground theatrical frame it is difficult for audients to develop the dual consciousness of the content, and their complicity in that content, that is the starting point for reflexivity, and response-ability, in the ethical encounter.

Preparing the actor for performance capture

Notions of capture and manipulation infer the existence of an interface that combines performer with system, an interface that separates (or intervenes in) the space between performance, intention and history. It is precisely the effect and provided opportunity of the intermediary device on the practice and craft of the actor, that is particularly examined in this work. Defining the scope of current practice for the contemporary actor is a key construct of this challenge with the most appropriate definition revolving around the pursuit of providing a required mixture of performance and content for live, mediated, framed and variously captured formats that exist in the present day. One of these particular formats is Performance Capture which this paper interrogate in more detail.

The HarmonyGrid : music, space and performance in grid music systems

This research explores music in space, as experienced through performing and music-making with interactive systems. It explores how musical parameters may be presented spatially and displayed visually with a view to their exploration by a musician during performance. Spatial arrangements of musical components, especially pitches and harmonies, have been widely studied in the literature, but the current capabilities of interactive systems allow the improvisational exploration of these musical spaces as part of a performance practice. This research focuses on quantised spatial organisation of musical parameters that can be categorised as grid music systems (GMSs), and interactive music systems based on them. The research explores and surveys existing and historical uses of GMSs, and develops and demonstrates the use of a novel grid music system designed for whole body interaction. Grid music systems provide plotting of spatialised input to construct patterned music on a two-dimensional grid layout. GMSs are navigated to construct a sequence of parametric steps, for example a series of pitches, rhythmic values, a chord sequence, or terraced dynamic steps. While they are conceptually simple when only controlling one musical dimension, grid systems may be layered to enable complex and satisfying musical results. These systems have proved a viable, effective, accessible and engaging means of music-making for the general user as well as the musician. GMSs have been widely used in electronic and digital music technologies, where they have generally been applied to small portable devices and software systems such as step sequencers and drum machines. This research shows that by scaling up a grid music system, music-making and musical improvisation are enhanced, gaining several advantages: (1) Full body location becomes the spatial input to the grid. The system becomes a partially immersive one in four related ways: spatially, graphically, sonically and musically. (2) Detection of body location by tracking enables hands-free operation, thereby allowing the playing of a musical instrument in addition to “playing” the grid system. (3) Visual information regarding musical parameters may be enhanced so that the performer may fully engage with existing spatial knowledge of musical materials. The result is that existing spatial knowledge is overlaid on, and combined with, music-space. Music-space is a new concept produced by the research, and is similar to notions of other musical spaces including soundscape, acoustic space, Smalley's “circumspace” and “immersive space” (2007, 48-52), and Lotis's “ambiophony” (2003), but is rather more textural and “alive”—and therefore very conducive to interaction. Music-space is that space occupied by music, set within normal space, which may be perceived by a person located within, or moving around in that space. Music-space has a perceivable “texture” made of tensions and relaxations, and contains spatial patterns of these formed by musical elements such as notes, harmonies, and sounds, changing over time. The music may be performed by live musicians, created electronically, or be prerecorded. Large-scale GMSs have the capability not only to interactively display musical information as music representative space, but to allow music-space to co-exist with it. Moving around the grid, the performer may interact in real time with musical materials in music-space, as they form over squares or move in paths. Additionally he/she may sense the textural matrix of the music-space while being immersed in surround sound covering the grid. The HarmonyGrid is a new computer-based interactive performance system developed during this research that provides a generative music-making system intended to accompany, or play along with, an improvising musician. This large-scale GMS employs full-body motion tracking over a projected grid. Playing with the system creates an enhanced performance employing live interactive music, along with graphical and spatial activity. Although one other experimental system provides certain aspects of immersive music-making, currently only the HarmonyGrid provides an environment to explore and experience music-space in a GMS.

Performance load testing and structural adequacy evaluation of road bridge decks

Many ageing road bridges, particularly timber bridges, require urgent improvement due to the demand imposed by the recent version of the Australian bridge loading code, AS 5100. As traffic volume plays a key role in the decision of budget allocations for bridge refurbishment/ replacement, many bridges in low volume traffic network remain in poor condition with axle load and/ or speed restrictions, thus disadvantaging many rural communities. This thesis examines an economical and environmentally sensible option of incorporating disused flat rail wagons (FRW) in the construction of bridges in low volume, high axle load road network. The constructability, economy and structural adequacy of the FRW road bridge is reported in the thesis with particular focus of a demonstration bridge commissioned in regional Queensland. The demonstration bridge comprises of a reinforced concrete slab (RCS) pavement resting on two FRWs with custom designed connection brackets at regular intervals along the span of the bridge. The FRW-RC bridge deck assembly is supported on elastomeric rubber pads resting on the abutment. As this type of bridge replacement technology is new and its structural design is not covered in the design standards, the in-service structural performance of the FRW bridge subjected to the high axle loadings prescribed in AS 5100 is examined through performance load testing. Both the static and the moving load tests are carried out using a fully laden commonly available three-axle tandem truck. The bridge deck is extensively strain gauged and displacement at several key locations is measured using linear variable displacement transducers (LVDTs). A high speed camera is used in the performance test and the digital image data are analysed using proprietary software to capture the locations of the wheel positions on the bridge span accurately. The wheel location is thus synchronised with the displacement and strain time series to infer the structural response of the FRW bridge. Field test data are used to calibrate a grillage model, developed for further analysis of the FRW bridge to various sets of high axle loads stipulated in the bridge design standard. Bridge behaviour predicted by the grillage model has exemplified that the live load stresses of the FRW bridge is significantly lower than the yield strength of steel and the deflections are well below the serviceability limit state set out in AS 5100. Based on the results reported in this thesis, it is concluded that the disused FRWs are competent to resist high axle loading prescribed in AS 5100 and are a viable alternative structural solution of bridge deck in the context of the low volume road networks.

“That you would post such a thing implies that you are a despicable human being”: spectatorship, social media, & the struggle for meaning in disability performance

Artists with disabilities working in Live Art paradigms often present performances which replay the social attitudes they are subject to in daily life as guerilla theatre in public spaces – including online spaces. In doing so, these artists draw spectators’ attention to the way their responses to disabled people contribute to the social construction of disability. They provide different theatrical, architectural or technological devices to encourage spectators to articulate their response to themselves and others. But – the use of exaggeration, comedy and confrontation in these practices notwithstanding – their blurry boundaries mean some spectators experience confusion as to whether they are responding to real life or a representation of it. This results in conflicted responses which reveal as much about the politics of disability as the performances themselves. In this paper, I examine how these conflicted responses play out in online forums. I discuss diverse examples, from blog comments on Liz Crow’s Resistance on the Plinth on YouTube, to Aaron Williamson and Katherine Araneillo’s Disabled Avant-Garde clips on YouTube, to Ju Gosling’s Letter Writing Project on her website, to segments of UK Channel 4’s mock reality show Cast Offs on YouTube. I demonstrate how online forums become a place not just for recording memories of an original performance (which posters may not have seen), but for a new performance, which goes well beyond re-membering/remediating the original. I identify trends in the way experience, memory and meaningmaking play out in these performative forums – moving from clarification of the original act’s parameters, to claims of disgust, insult or offense, to counter-claims confirming the comic or political efficacy of the act, often linked disclosure of personal memory or experience of disability. I examine the way these encounters at the interstices of live and/or online performance, memory, technology and public/private history negotiate ideas about disability, and what they tell us about the ethics and efficacy of the specific modes of performance and spectatorship these artists with disabilities are invoking.

Preparing for performance capture #1

This video article articulates two exercises that have been developed to respond to the need for preparedness in the growing field of Performance Capture. The first is called Walking Through (Delbridge 2013), where the actor navigates a series of objects that exist in screen space through a developed sense of the existing physical particularities of the studio and an interaction with a screen (or feedback loop). The second exercise is called The Donut (Delbridge 2013), where the performer continues to navigate screen space but this time does so through the literal stepping through of a Torus in the virtual – again with nothing but the studio infrastructure and the screen as a guide. Notions of Motion Captured performance infer the existence of an interface that combines performer with system, separating (or intervening in) the space between performance and the screen. It is precisely the effect and provided opportunity of the intermediary device on the practice, craft and preparedness of the actor as they navigate the connection between 3D screen space and the physical properties of the studio that is examined here. Defining the scope of current practice for the contemporary actor is a key construct of this challenge, with the most appropriate definition revolving around the provision of a required mixture of performance and content for live, mediated, framed and variously captured formats. One of these particular formats is Performance Capture. The exercises presented here are two from a series, developed over a three year study that contribute to our understanding of the potential for a training regimen to be developed for the rigors of Performance Capture.

Australia’s rural youth, online storytelling and identity performance

Online storytelling spaces provide young people who live in rural and remote parts of Australia with an opportunity to develop their personal identities and connect and communicate with other young people. The Australian Broadcasting Corporation’s (ABC’s) rural and regional youth network, Heywire, is such a space (http://www.abc.net.au/heywire/). Heywire invites 16-22 year old Australians who identify as ‘rural’ or ‘regional’ to create an online profile and upload stories about their lives in the form of text, audio, video or photographs. Emerging from my PhD project, this paper describes how rural and regional youth perform their identities through creating stories for the Heywire website, addressing notions of individual and social identities as a sub-theme. Compared with their city counterparts, the youth who live in regional towns or isolated properties have fewer opportunities to socialise with other people their own age. Subsequently computer mediated technologies, particularly the internet, can enable this group of people to connect with each other and develop a sense of community. In this paper I outline how these possibilities exist within an online storytelling space. I describe a number of reasons for young people’s story-sharing on the Heywire website in order to demonstrate the potential for spaces such as this to enable isolated youth to experience a sense of connection and belonging, despite geographical dispersion and physical isolation.

Disability, public space performance & spectatorship : Unconscious performers

Why would disabled people want to re-engage, re-enact and re-envisage the everyday encounters in public spaces and places that cast them as ugly, strange, stare-worthy? In Disability, Public Space Performance and Spectatorship: Unconscious Performers, Bree Hadley examines the performance practices of disabled artists in the US, UK, Europe and Australasia who do exactly this. Operating in a live or performance art paradigm, artists like James Cunningham (Australia), Noemi Lakmaier (UK/Austria), Alison Jones (UK), Aaron Williamson (UK), Katherine Araniello (UK), Bill Shannon (US), Back to Back Theatre (Australia), Rita Marcalo (UK), Liz Crow (UK) and Mat Fraser (UK) all use installation and public space performance practices to re-stage their disabled identities in risky, guerilla-style works that remind passersby of their own complicity in the daily social drama of disability. In doing so, they draw spectators' attention to their own role in constructing Western concepts of disability. This book investigates the way each of us can become unconscious performers in a daily social drama that positions disability people as figures of tragedy, stigma or pity, and the aesthetics, politics and ethics of performance practices that intervene very directly in this drama. It constructs a framework for understanding the way spectators are positioned in these practices, and how they contribute to public sphere debates about disability today.

A random key genetic algorithm for live migration of multiple virtual machines in data centers

Live migration of multiple Virtual Machines (VMs) has become an integral management activity in data centers for power saving, load balancing and system maintenance. While state-of-the-art live migration techniques focus on the improvement of migration performance of an independent single VM, only a little has been investigated to the case of live migration of multiple interacting VMs. Live migration is mostly influenced by the network bandwidth and arbitrarily migrating a VM which has data inter-dependencies with other VMs may increase the bandwidth consumption and adversely affect the performances of subsequent migrations. In this paper, we propose a Random Key Genetic Algorithm (RKGA) that efficiently schedules the migration of a given set of VMs accounting both inter-VM dependency and data center communication network. The experimental results show that the RKGA can schedule the migration of multiple VMs with significantly shorter total migration time and total downtime compared to a heuristic algorithm.

Live and analogue : Theatre as a practice of social inclusion

This monograph argues for a repositioning of theatre as an antidote to the negative effects of the reduction of live social interaction among the current generation of young people. It argues for a repositioned valuing of the role that live performing arts can play in the development of social cohesion and well-being with young people. Highlighted therefore is an emphasis on developing ‘communitas’ or ‘collective joy’ (Turner, 2012) for young audiences. Using the lens of social acupuncture (O’Donnell, 2006) the monograph explores how two Australian live theatre or performance events – The Walking Neighbourhood and 지하 Underground – foreground inclusionary audience experiences. It concludes with a challenge to drama teachers, theatre makers, arts researchers, arts programmers and performance venue managers regarding how they might view their young audiences as more than just a marketing demographic and income stream, by providing new platforms for young people’s social cohesion and well-being.

Evaluation of partial replacement of live and fresh feeds with a formulated diet and the influence of weaning Panulirus ornatus phyllosomata onto a formulated diet during early ontogeny

We have evaluated the potential of a formulated diet as a replacement for live and fresh feeds for 7-day post-hatch Panulirus ornatus phyllosomata and also investigated the effect of conditioning phyllosomata for 14-21 days on live feeds prior to weaning onto a 100% formulated diet. In the first trial, the highest survival (>55%) was consistently shown by phyllosomata fed a diet consisting of a 50% combination of Artemia nauplii and 50% Greenshell mussel, followed by phyllosomata fed 50% Artemia nauplii and 50% formulated diet and, thirdly, by those receiving 100% Artemia nauplii. The second trial assessed the replacement of on-grown Artemia with proportions of formulated diet and Greenshell mussel that differed from those used in trial 1. Phyllosomata fed a 75% combination of formulated diet and 25% on-grown Artemia and 50% on-grown Artemia and 50% Greenshell mussel consistently showed the highest survival (>75%). Combinations of Greenshell mussel and formulated diet resulted in significantly (P < 0.05) reduced survival. In trial 3, phyllosomata were conditioned for 14, 18 or 21 days on Artemia nauplii prior to weaning onto a 100% formulated diet, which resulted in survival rates that were negatively related to the duration of feeding Artemia nauplii. In the final trial, phyllosomata were conditioned for 14 days on live on-grown Artemia prior to weaning onto one of three formulated diets (one diet with 44% CP and two diets with 50%). Phyllosomata fed a 44% CP diet consistently showed the highest survival (>35%) among all treatments, while those fed a 50%-squid CP diet showed a significant (P < 0.05) increase in mortality at day 24. The results of these trials demonstrate that hatcheries can potentially replace 75% of live on-grown Artemia with a formulated diet 7 days after hatch. The poor performance associated with feeding combinations of Greenshell mussel and formulated diet, and 100% formulated diet as well as conditioning phyllosomata for 14-21 days on live feeds prior to weaning onto a formulated diet highlights the importance of providing Artemia to stimulate feeding.

Probiotic Bacillus amyloliquefaciens Strain H57 Improves the Performance of Pregnant and Lactating Ewes Fed a Diet Based on Palm Kernel Meal

Probiotic supplements are single or mixed strain cultures of live microorganisms that benefit the host by improving the properties of the indigenous microflora (Seo et al 2010). In a pilot study at the University of Queensland, Norton et al (2008) found that Bacillus amyloliquefaciens Strain H57 (H57), primarily investigated as an inoculum to make high-quality hay, improved feed intake and nitrogen utilisation over several weeks in pregnant ewes. The purpose of the following study was to further challenge the potential of H57 -to show it survives the steam-pelleting process, and that it improves the performance of ewes fed pellets based on an agro-industrial by-product with a reputation for poor palatability, palm kernel meal (PKM), (McNeill 2013). Thirty-two first-parity White Dorper ewes (day 37 of pregnancy, mean liveweight = 47.3 kg, mean age = 15 months) were inducted into individual pens in the animal house at the University of Queensland, Gatton. They were adjusted onto PKM-based pellets (g/kg drymatter (DM): PKM, 408; sorghum, 430; chick pea hulls, 103; minerals and vitamins; Crude protein, 128; ME: 11.1MJ/kg DM) until day 89 of pregnancy and thereafter fed a predominately pelleted diet incorporating with or without H57 spores (10 9 colony forming units (cfu)/kg pellet, as fed), plus 100g/ewe/day oaten chaff, until day 7 of lactation. From day 7 to 20 of lactation the pelleted component of the diet was steadily reduced to be replaced by a 50:50 mix of lucerne: oaten chaff, fed ad libitum, plus 100g/ewe/day of ground sorghum grain with or without H57 (10 9 cfu/ewe/day). The period of adjustment in pregnancy (day 37-89) extended beyond expectations due to some evidence of mild ruminal acidosis after some initially high intakes that were followed by low intakes. During that time the diet was modified, in an attempt to improve palatability, by the addition of oaten chaff and the removal of an acidifying agent (NH4Cl) that was added initially to reduce the risk of urinary calculi. Eight ewes were removed due to inappetence, leaving 24 ewes to start the trial at day 90 of pregnancy. From day 90 of pregnancy until day 63 of lactation, liveweights of the ewes and their lambs were determined weekly and at parturition. Feed intakes of the ewes were determined weekly. Once lambing began, 1 ewe was removed as it gave birth to twin lambs (whereas the rest gave birth to a single lamb), 4 due to the loss of their lambs (2 to dystocia), and 1 due to copper toxicity. The PKM pellets were suspected to be the cause of the copper toxicity and so were removed in early lactation. Hence, the final statistical analysis using STATISTICA 8 (Repeated measures ANOVA for feed intake, One-way ANOVA for liveweight change and birth weight) was completed on 23 ewes for the pregnancy period (n = 11 fed H57; n = 12 control), and 18 ewes or lambs for the lactation period (n = 8 fed H57; n = 10 control). From day 90 of pregnancy until parturition the H57 supplemented ewes ate 17 more DM (g/day: 1041 vs 889, sed = 42.4, P = 0.04) and gained more liveweight (g/day: 193 vs 24.0, sed = 25.4, P = 0.0002), but produced lambs with a similar birthweight (kg: 4.18 vs 3.99, sed = 0.19, P = 0.54). Over the 63 days of lactation the H57 ewes ate similar amounts of DM but grew slower than the control ewes (g/day: 1.5 vs 97.0, sed = 21.7, P = 0.012). The lambs of the H57 ewes grew faster than those of the control ewes for the first 21 days of lactation (g/day: 356 vs 265, sed = 16.5, P = 0.006). These data support the findings of Norton et al (2008) and Kritas et al (2006) that certain Bacillus spp. supplements can improve the performance of pregnant and lactating ewes. In the current study we particularly highlighted the capacity of H57 to stimulate immature ewes to continue to grow maternal tissue through pregnancy, possibly through an enhanced appetite, which appeared then to stimulate a greater capacity to partition nutrients to their lambs through milk, at least for the first few weeks of lactation, a critical time for optimising lamb survival. To conclude, H57 can survive the steam pelleting process to improve feed intake and maternal liveweight gain in late pregnancy, and performance in early lactation, of first-parity ewes fed a diet based on PKM.