1,721,262 research outputs found
Notes and Comments. The density of the maximum likelihood estimator
No full textIn this paper we give a formula for the exact density of the MAXIMUM LIKELIHOOD ESTIMATOR (MLE) under regularity conditions that also has this property, and thus provide a means for obtaining (at least in principle) exact results even in cases where the estimator is only implicitly defined by the usual likelihood equations. Such an analysis has hitherto been inaccessible by standard exact distribution-theoretic methods. The argument is readily extended to estimators other than the MLE method of moments estimators, for example, although we do not pursue that extension here
Journalists and online media: The engagement of journalists in creating new forms of media content, presentation and service to publics; a case study approach and reflection on practice
Full text linkThe paper examines the translation of journalism as it has been known into new media forms, principally its contribution to content-making for online services. It rests on the significance of content: what media are available to carry certain content; what content is being provided by certain media? The paper is in two parts: First, it reviews an explosion of activity in the online journalism field; it notes adaptation and innovation which this has produced, and considers future possibilities. Second, it provides a case study based on an online service launched by the author, in the context of findings made by the above review, illustrating aspects of it. A movement has taken hold among journalists internationally to exploit the possibilities of online publishing. News organisations have come forward to position themselves among leading providers of online services, and apart from that, practising journalists as individuals and in groups have taken up the new medium in novel ways. The article refers to work under way, on craft issues (developments in how to write, illustrate, represent using this medium); on economics and resources of online publishing; adaptation to different types of online media; and reporting practices. Content issues arise: Online media through making new markets generate more specialised and creative journalistic work, both in terms of what information appears and how that information is worked into the fabric of the presentation. In a case study the author recounts setting up an online service that provides specialised international news, as a reflection on practice. The case study traces conceptualisation of the service, funding, and construction of a website using modified "blog" software. It recounts the development of a journalistic modus operandi and style, experience of ten months\u27 operations, and accumulation of an audience. It will describe the project as being in various essentials, an example of independent journalistic exercises around the world. It will especially look at content issues _ surveillance, selection of material, writing, matters of presentation and illustration. Taking a segmented approach to proliferating new media, by looking at the contribution of journalism-in-place, narrows down the field of inquiry and makes it manageable. It may help with an understanding of certain central questions: what is the relationship between media formats and content; what familiar contents material is being accommodated; what new content is being induced by the nature of the media? It should add to understanding of new media in mass communication generally
Mechanical Performance of Layered PLA–TPU Composites Using Multi-Material Additive Manufacturing
Full text linkThis study investigates the behaviour and tensile performance of multi-material additive manufacturing (MMAM) by fused deposition modelled (FDM) laminates composed of polylactic acid (PLA) and thermoplastic polyurethane (TPU). The work aims to establish the relationship between layer configuration, material sequence, and deformation mechanisms in rigid–compliant polymer systems. Single-material PLA and TPU specimens were first characterised to establish baseline mechanical behaviour, followed by six laminate architectures combining PLA and TPU in alternating layers. Tensile testing was conducted with apparent stiffness values derived from crosshead displacement and failure modes documented through post-fracture imaging. Results show that PLA exhibited brittle fracture with minimal necking, while TPU demonstrated extensive elongation and stress whitening prior to rupture. The laminates displayed intermediate mechanical properties, achieving improved ductility compared with pure PLA and higher strength than TPU. The strongest configuration, a PLA/TPU/PLA laminate with thinner layers (0.1 mm), reached an average ultimate tensile strength (UTS) of 33.5 MPa and elongation of 7.7%, reflecting effective stress transfer across the interface. Fracture analysis revealed mixed brittle–ductile morphologies and limited delamination, indicating partial interlayer adhesion despite the intrinsic surface-energy mismatch between PLA and TPU. The findings highlight the feasibility of combining dissimilar thermoplastics within a single FDM build to achieve tuneable mechanical response. However, the results also highlight the need for interfacial improvement through diffusion optimisation or compatibilisation to fully exploit the potential of multi-material polymer additive manufacturing for high-performance structural and flexible systems
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Comparison Analysis of Energy Consumption of Atomic Diffusion Additive Manufacturing with Sand Casting: Towards a more Sustainable Future
Full text linkOver the years, the cumulative environmental impact from human activity has disrupted the stability of the natural world, warming the planet above pre-industrial levels. Whilst unprecedented in many ways, reducing industrial emissions from greenhouse gases could help stabilise rising temperatures. Thus, the exploration for more sustainable manufacturing solutions that reduce carbon emissions is imperative. Some traditional manufacturing (TM) processes, such as sand casting, which, despite its versatility to produce products in many shapes and sizes from almost any metal or alloy, are typically energy-intensive activities. Conversely, metal additive manufacturing (MAM) enables users to manufacture more complex, lighter and near net shapes with the ability to consolidate manufacturing workflows. Consequently, MAM has been reported to be an energy-efficient alternative. Yet, evidence in the literature on the environmental impact of some MAM processes is limited, especially for material extrusion (ME) additive manufacturing (AM) methods such as the atomic diffusion additive manufacturing (ADAM) process. This paper explores the feasibility of performing a life cycle assessment (LCA) for the ADAM process compared to sand casting. Preliminary results indicate that the ADAM process demands 71.04 kWh/kg and 16.57 CO2 equivalent (CO2-eq) more for manufacturing 1kg of 17-4 precipitation hardened stainless steel (17-4 PH SS) compared to sand casting. Therefore, the findings collected from this pilot study justify future research efforts to converge on developing a novel model for performing a comprehensive cradle to grave LCA for ADAM to compare against sand casting and other TM processes such as CNC milling and investment casting
Journalism as social networking: The Australian youdecideproject and the 2007 Federal election
Full text linkThe increasing prevalence of new media technologies and the rise of citizen journalism has coincided with a crisis in industrial journalism, as the figure of the \u27journalist as hero\u27 is fading, new media forms have facilitated the production of news content \u27from below\u27 by citizens and \u27roam\u27 journalists. Participation in an action-research project run during the 2007 Australian Federal Election, you decide 2007, allowed the authors to gain first-hand insights into the progress of citizen-led news media in Australia, but also allowed us to develop an account of what the work of facilitating citizen journalism involves. These insights are important to understanding the future of professional journalism and journalism education, as more mainstream media organizations move to accommodate and harness user-created content. The paper considers the relevance of citizen journalism projects as forms of R&D for understanding news production and distribution in participatory media cultures, and the importance of grounded case studies for moving beyond normative debates about new media and the future of journalism
Bringing the internet down to earth : emerging spaces of locative media
No full textWeb 1.0 referred to the early, read-only internet; Web 2.0 refers to the ‘read-write web’ in which users actively contribute to as well as consume online content; Web 3.0 is now being used to refer to the convergence of mobile and Web 2.0 technologies and applications. One of the most important developments in mobile 3.0 is geography: with many mobile phones now equipped with GPS, mobiles promise to “bring the internet down to earth” through geographically-aware, or locative media. The internet was earlier heralded as “the death of geography” with predictions that with anyone able to access information from anywhere, geography would no longer matter. But mobiles are disproving this. GPS allows the location of the user to be pinpointed, and the mobile internet allows the user to access locally-relevant information, or to upload content which is geotagged to the specific location. It also allows locally-specific content to be sent to the user when the user enters a specific space. Location-based services are one of the fastest-growing segments of the mobile internet market: the 2008 AIMIA report indicates that user access of local maps increased by 347% over the previous 12 months, and restaurant guides/reviews increased by 174%. \ud
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The central tenet of cultural geography is that places are culturally-constructed, comprised of the physical space itself, culturally-inflected perceptions of that space, and people’s experiences of the space (LeFebvre 1991). This paper takes a cultural geographical approach to locative media, anatomising the various spaces which have emerged through locative media, or “the geoweb” (Lake 2004). The geoweb is such a new concept that to date, critical discourse has treated it as a somewhat homogenous spatial formation. In order to counter this, and in order to demonstrate the dynamic complexity of the emerging spaces of the geoweb, the paper provides a topography of different types of locative media space: including the personal/aesthetic in which individual users geotag specific physical sites with their own content and meanings; the commercial, like the billboards which speak to individuals as they pass in Minority Report; and the social, in which one’s location is defined by the proximity of friends rather than by geography. \u
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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