Least-squares congealing for large numbers of images

In this paper we pursue the task of aligning an ensemble of images in an unsupervised manner. This task has been commonly referred to as “congealing” in literature. A form of congealing, using a least-squares criteria, has been recently demonstrated to have desirable properties over conventional congealing. Least-squares congealing can be viewed as an extension of the Lucas & Kanade (LK)image alignment algorithm. It is well understood that the alignment performance for the LK algorithm, when aligning a single image with another, is theoretically and empirically equivalent for additive and compositional warps. In this paper we: (i) demonstrate that this equivalence does not hold for the extended case of congealing, (ii) characterize the inherent drawbacks associated with least-squares congealing when dealing with large numbers of images, and (iii) propose a novel method for circumventing these limitations through the application of an inverse-compositional strategy that maintains the attractive properties of the original method while being able to handle very large numbers of images.

New methodologies for researching news discussion on Twitter

Twitter has become a major instrument for the rapid dissemination and subsequent debate of news stories. It has been instrumental both in drawing attention to events as they unfolded (such as the emergency landing of a plane in New York’s Hudson River in 2009) and in facilitating a sustained discussion of major stories over timeframes measured in weeks and months (including the continuing saga around Wikileaks and Julian Assange), sometimes still keeping stories alive even if mainstream media attention has moved on elsewhere. More comprehensive methodologies for research into news discussion on Twitter – beyond anecdotal or case study approaches – are only now beginning to emerge. This paper presents a large-scale quantitative approach to studying public communication in the Australian Twittersphere, developed as part of a three-year ARC Discovery project that also examines blogs and other social media spaces. The paper will both outline the innovative research tools developed for this work, and present outcomes from an application of these methodologies to recent and present news themes. Our methodology enables us to identify major themes in Twitter’s discussion of these events, trace their development and decline over time, and map the dynamics of the discussion networks formed ad hoc around specific themes (in part with the help of Twitter #hashtags: brief identifiers which mark a tweet as taking part in an established discussion). It is also able to identify links to major news stories and other online resources, and to track their dissemination across the wider Twittersphere.

Towards distributed citizen participation : lessons from WikiLeaks and the Queensland Floods

This paper examines the rapid and ad hoc development and interactions of participative citizen communities during acute events, using the examples of the 2011 floods in Queensland, Australia, and the global controversy surrounding Wikileaks and its spokesman, Julian Assange. The self-organising community responses to such events which can be observed in these cases bypass or leapfrog, at least temporarily, most organisational or administrative hurdles which may otherwise frustrate the establishment of online communities; they fast-track the processes of community development and structuration. By understanding them as a form of rapid prototyping, e-democracy initiatives can draw important lessons from observing the community activities around such acute events.

The use of Twitter hashtags in the formation of ad hoc publics

As the use of Twitter has become more commonplace throughout many nations, its role in political discussion has also increased. This has been evident in contexts ranging from general political discussion through local, state, and national elections (such as in the 2010 Australian elections) to protests and other activist mobilisation (for example in the current uprisings in Tunisia, Egypt, and Yemen, as well as in the controversy around Wikileaks). Research into the use of Twitter in such political contexts has also developed rapidly, aided by substantial advancements in quantitative and qualitative methodologies for capturing, processing, analysing, and visualising Twitter updates by large groups of users. Recent work has especially highlighted the role of the Twitter hashtag – a short keyword, prefixed with the hash symbol ‘#’ – as a means of coordinating a distributed discussion between more or less large groups of users, who do not need to be connected through existing ‘follower’ networks. Twitter hashtags – such as ‘#ausvotes’ for the 2010 Australian elections, ‘#londonriots’ for the coordination of information and political debates around the recent unrest in London, or ‘#wikileaks’ for the controversy around Wikileaks thus aid the formation of ad hoc publics around specific themes and topics. They emerge from within the Twitter community – sometimes as a result of pre-planning or quickly reached consensus, sometimes through protracted debate about what the appropriate hashtag for an event or topic should be (which may also lead to the formation of competing publics using different hashtags). Drawing on innovative methodologies for the study of Twitter content, this paper examines the use of hashtags in political debate in the context of a number of major case studies.

Interactive processes link the multiple symptoms of fatigue in sport competition

Muscle physiologists often describe fatigue simply as a decline of muscle force and infer this causes an athlete to slow down. In contrast, exercise scientists describe fatigue during sport competition more holistically as an exercise-induced impairment of performance. The aim of this review is to reconcile the different views by evaluating the many performance symptoms/measures and mechanisms of fatigue. We describe how fatigue is assessed with muscle, exercise or competition performance measures. Muscle performance (single muscle test measures) declines due to peripheral fatigue (reduced muscle cell force) and/or central fatigue (reduced motor drive from the CNS). Peak muscle force seldom falls by >30% during sport but is often exacerbated during electrical stimulation and laboratory exercise tasks. Exercise performance (whole-body exercise test measures) reveals impaired physical/technical abilities and subjective fatigue sensations. Exercise intensity is initially sustained by recruitment of new motor units and help from synergistic muscles before it declines. Technique/motor skill execution deviates as exercise proceeds to maintain outcomes before they deteriorate, e.g. reduced accuracy or velocity. The sensation of fatigue incorporates an elevated rating of perceived exertion (RPE) during submaximal tasks, due to a combination of peripheral and higher CNS inputs. Competition performance (sport symptoms) is affected more by decision-making and psychological aspects, since there are opponents and a greater importance on the result. Laboratory based decision making is generally faster or unimpaired. Motivation, self-efficacy and anxiety can change during exercise to modify RPE and, hence, alter physical performance. Symptoms of fatigue during racing, team-game or racquet sports are largely anecdotal, but sometimes assessed with time-motion analysis. Fatigue during brief all-out racing is described biomechanically as a decline of peak velocity, along with altered kinematic components. Longer sport events involve pacing strategies, central and peripheral fatigue contributions and elevated RPE. During match play, the work rate can decline late in a match (or tournament) and/or transiently after intense exercise bursts. Repeated sprint ability, agility and leg strength become slightly impaired. Technique outcomes, such as velocity and accuracy for throwing, passing, hitting and kicking, can deteriorate. Physical and subjective changes are both less severe in real rather than simulated sport activities. Little objective evidence exists to support exercise-induced mental lapses during sport. A model depicting mind-body interactions during sport competition shows that the RPE centre-motor cortex-working muscle sequence drives overall performance levels and, hence, fatigue symptoms. The sporting outputs from this sequence can be modulated by interactions with muscle afferent and circulatory feedback, psychological and decision-making inputs. Importantly, compensatory processes exist at many levels to protect against performance decrements. Small changes of putative fatigue factors can also be protective. We show that individual fatigue factors including diminished carbohydrate availability, elevated serotonin, hypoxia, acidosis, hyperkalaemia, hyperthermia, dehydration and reactive oxygen species, each contribute to several fatigue symptoms. Thus, multiple symptoms of fatigue can occur simultaneously and the underlying mechanisms overlap and interact. Based on this understanding, we reinforce the proposal that fatigue is best described globally as an exercise-induced decline of performance as this is inclusive of all viewpoints.

Service delivery in one-stop government portals : observations based on a market research study in Queensland

New government service delivery models based on a “franchise” metaphor are being proposed recently to allow more citizen-centric service delivery by decoupling the government’s internal departmental structure from the way services are presented and delivered to citizens. In order to evaluate the approach from an online channel perspective, the Queensland Government commissioned a market research study to compare their websites with the online presences of the UK Government and the South Australian Government, who both have adopted the “franchise” approach. The study aimed to inform an understanding of citizens’ preferred model for interacting in the online channel and to identify the relative strengths and weaknesses of the existing websites. In this paper, we will a) report on the findings of this third party usability study and b) position the study, in the form of a critical reflection, against the background of a more comprehensive “Transformational Government” approach using a “franchise marketplace”. The critical reflection points towards limitations of the study with regard to this bigger picture and discusses the potential benefits of service bundling that remained unconsidered in the study.

Where do we find services in enterprise architectures? A comparative approach

In recent years, enterprise architecture (EA) has captured growing attention as a means to systematically consolidate and interrelate diverse IT artefacts in order to provide holistic decision support. Since the emergence of Service-Oriented Architecture (SOA), many attempts have been made to incorporate SOA artefacts in existing EA frameworks. Yet the approaches taken to achieve this goal differ substantially for the most commonly used EA frameworks to date. This paper investigates and compares five widely used EA frameworks in the way they embrace the SOA paradigm. It identifies what SOA artefacts are considered to be in the respective EA frameworks and their relative position in the overall structure. The results show that services and related artefacts are far from being well-integrated constructs in current EA frameworks. The comparison presented in this paper will support practitioners in identifying an EA framework that provides SOA support in a way that matches their requirements and will hopefully inspire the academic EA and SOA communities to work on a closer integration of these architectures.

Enterprise architecture and the integration of service-oriented architecture

In recent years, enterprise architecture (EA) has captured a growing attention as a means to systematically consolidate and interrelate diverse business and IT artefacts in order to provide holistic decision support. The recent popularity of a service-orientation has added “service “and related constructs as a new element that requires consideration within an Enterprise Architecture. Since the emergence of the Service-Oriented Architecture (SOA), many attempts have been made to incorporate SOA artefacts in existing EA frameworks. Yet, the approaches taken to achieve this goal differ substantially for the most commonly used EA frameworks to date. SOA in the context of enterprise architecture is one of the future research challenges. Several authors argue that further research is needed in order to understand how SOA impacts prior enterprise architecture frameworks. This study explores SOA integration within EA, identifies SOA integration approaches within EA and identifies factors that impact SOA integration within Enterprise Architecture.

Gatekeeping, gatewatching, real-time feedback : new challenges for Journalism

How bloggers and other independent online commentators criticise, correct, and otherwise challenge conventional journalism has been known for years, but has yet to be fully accepted by journalists; hostilities between the media establishment and the new generation of citizen journalists continue to flare up from time to time. The old gatekeeping monopoly of the mass media has been challenged by the new practice of gatewatching: by individual bloggers and by communities of commentators which may not report the news first-hand, but curate and evaluate the news and other information provided by official sources, and thus provide an important service. And this now takes place ever more rapidly, almost in real time: using the latest social networks, which disseminate, share, comment, question, and debunk news reports within minutes, and using additional platforms that enable fast and effective ad hoc collaboration between users. When hundreds of volunteers can prove within a few days that a German minister has been guilty of serious plagiarism, when the world first learns of earthquakes and tsunamis via Twitter – how does journalism manage to keep up?

#Ausvotes : how Twitter covered the 2010 Australian federal election

While the 2007 Australian federal election was notable for the use of social media by the Australian Labor Party in campaigning, the 2010 election took place in a media landscape in which social media–especially Twitter–had become much more embedded in both political journalism and independent political commentary. This article draws on the computer-aided analysis of election-related Twitter messages, collected under the #ausvotes hashtag, to describe the key patterns of activity and thematic foci of the election’s coverage in this particular social media site. It introduces novel metrics for analysing public communication via Twitter, and describes the related methods. What emerges from this analysis is the role of the #ausvotes hashtag as a means of gathering an ad hoc ‘issue public’– a finding which is likely to be replicated for other hashtag communities.

How long is a tweet? Mapping dynamic conversation networks on Twitter using Gawk and Gephi

Twitter is now well established as the world’s second most important social media platform, after Facebook. Its 140-character updates are designed for brief messaging, and its network structures are kept relatively flat and simple: messages from users are either public and visible to all (even to unregistered visitors using the Twitter website), or private and visible only to approved ‘followers’ of the sender; there are no more complex definitions of degrees of connection (family, friends, friends of friends) as they are available in other social networks. Over time, Twitter users have developed simple, but effective mechanisms for working around these limitations: ‘#hashtags’, which enable the manual or automatic collation of all tweets containing the same #hashtag, as well allowing users to subscribe to content feeds that contain only those tweets which feature specific #hashtags; and ‘@replies’, which allow senders to direct public messages even to users whom they do not already follow. This paper documents a methodology for extracting public Twitter activity data around specific #hashtags, and for processing these data in order to analyse and visualize the @reply networks existing between participating users – both overall, as a static network, and over time, to highlight the dynamic structure of @reply conversations. Such visualizations enable us to highlight the shifting roles played by individual participants, as well as the response of the overall #hashtag community to new stimuli – such as the entry of new participants or the availability of new information. Over longer timeframes, it is also possible to identify different phases in the overall discussion, or the formation of distinct clusters of preferentially interacting participants.

#qldfloods and @QPSMedia: Crisis Communication on Twitter in the 2011 South East Queensland Floods

Social media, including Facebook and Twitter, played an important role in crisis communication at the height of the 2011 South East Queensland floods crisis (10-16 January). This report examines the role of the short-messaging system Twitter in disseminating and sharing crisis information and updates from state and local authorities as well as everyday citizens. We assess the overall use of Twitter, as well as that of the most important emergency service account, the Queensland Police’s @QPSMedia account.

Beyond difference : reconfiguring education for the user-led age

In recent years, various observers have pointed to the shifting paradigms of cultural and societal participation and economic production in developed nations. These changes are facilitated (although, importantly, not solely driven) by the emergence of new, participatory technologies of information access, knowledge exchange, and content production, many of whom are associated with Internet and new media technologies. In an online context, such technologies are now frequently described as social software, social media, or Web2.0, but their impact is no longer confined to cyberspace as an environment that is somehow different and separate from ‘real life’: user-led content and knowledge production is increasingly impacting on media, economy, law, social practices, and democracy itself.

Produsage: a closer look at continuing developments

The concept of produsage developed from the realisation that new language was needed to describe the new phenomena emerging from the intersection of Web 2.0, user-generated content, and social media since the early years of the new millennium. When hundreds, thousands, maybe tens of thousands of participants utilise online platforms to collaborate in the development and continuous improvement of a wide variety of content – from software to informational resources to creative works –, and when this work takes place through a series of more or less unplanned, ad hoc, almost random cooperative encounters, then to describe these processes using terms which were developed during the industrial revolution no longer makes much sense. When – exactly because what takes place here is no longer a form of production in any conventional sense of the word – the outcomes of these massively distributed collaborations appear in the form of constantly changing, permanently mutable bodies of work which are owned at once by everyone and no-one, by the community of contributors as a whole but by none of them as individuals, then to conceptualise them as fixed and complete products in the industrial meaning of the term is missing the point. When what results from these efforts is of a quality (in both depth and breadth) that enables it to substitute for, replace, and even undermine the business model of long-established industrial products, even though precariously it relies on volunteer contributions, and when their volunteering efforts make it possible for some contributors to find semi- or fully professional employment in their field, then conventional industrial logic is put on its head.