624 resultados para Heterogeneous porous media
Resumo:
In recent years, rapid advances in information technology have led to various data collection systems which are enriching the sources of empirical data for use in transport systems. Currently, traffic data are collected through various sensors including loop detectors, probe vehicles, cell-phones, Bluetooth, video cameras, remote sensing and public transport smart cards. It has been argued that combining the complementary information from multiple sources will generally result in better accuracy, increased robustness and reduced ambiguity. Despite the fact that there have been substantial advances in data assimilation techniques to reconstruct and predict the traffic state from multiple data sources, such methods are generally data-driven and do not fully utilize the power of traffic models. Furthermore, the existing methods are still limited to freeway networks and are not yet applicable in the urban context due to the enhanced complexity of the flow behavior. The main traffic phenomena on urban links are generally caused by the boundary conditions at intersections, un-signalized or signalized, at which the switching of the traffic lights and the turning maneuvers of the road users lead to shock-wave phenomena that propagate upstream of the intersections. This paper develops a new model-based methodology to build up a real-time traffic prediction model for arterial corridors using data from multiple sources, particularly from loop detectors and partial observations from Bluetooth and GPS devices.
Resumo:
As patterns of media use become more integrated with mobile technologies and multiple screens, a new mode of viewer engagement has emerged in the form of connected viewing, which allows for an array of new relationships between audiences and media texts in the digital space. This exciting new collection brings together twelve original essays that critically engage with the socially-networked, multi-platform, and cloud-based world of today, examining the connected viewing phenomenon across television, film, video games, and social media. The result is a wide-ranging analysis of shifting business models, policy matters, technological infrastructure, new forms of user engagement, and other key trends affecting screen media in the digital era. Connected Viewing contextualizes the dramatic transformations taking place across both media industries and national contexts, and offers students and scholars alike a diverse set of methods and perspectives for studying this critical moment in media culture.
Resumo:
All media are social—they are after all media, in between, intermediating between producers and consumers of content, information, conversation, between the actors in the media and the audiences who read, listen, and watch. And the sociality of the media does not stop there: the processes of media production are social processes just as much as the activities of media audiencing. So strictly speaking, all media are social media. But only a particular subset of all media are fundamentally defined by their sociality, and thus distinguished from the mainstream media of print, radio, and television. It is the actual uses which are made of any medium which determine whether it is indeed a social medium—so let us investigate their roles in and interplay with the societies in which they operate.
Resumo:
Invasive non-native plants have negatively impacted on biodiversity and ecosystem functions world-wide. Because of the large number of species, their wide distributions and varying degrees of impact, we need a more effective method for prioritizing control strategies for cost-effective investment across heterogeneous landscapes. Here, we develop a prioritization framework that synthesizes scientific data, elicits knowledge from experts and stakeholders to identify control strategies, and appraises the cost-effectiveness of strategies. Our objective was to identify the most cost-effective strategies for reducing the total area dominated by high-impact non-native plants in the Lake Eyre Basin (LEB). We use a case study of the ˜120 million ha Lake Eyre Basin that comprises some of the most distinctive Australian landscapes, including Uluru-Kata Tjuta National Park. More than 240 non-native plant species are recorded in the Lake Eyre Basin, with many predicted to spread, but there are insufficient resources to control all species. Lake Eyre Basin experts identified 12 strategies to control, contain or eradicate non-native species over the next 50 years. The total cost of the proposed Lake Eyre Basin strategies was estimated at AU$1·7 billion, an average of AU$34 million annually. Implementation of these strategies is estimated to reduce non-native plant dominance by 17 million ha – there would be a 32% reduction in the likely area dominated by non-native plants within 50 years if these strategies were implemented. The three most cost-effective strategies were controlling Parkinsonia aculeata, Ziziphus mauritiana and Prosopis spp. These three strategies combined were estimated to cost only 0·01% of total cost of all the strategies, but would provide 20% of the total benefits. Over 50 years, cost-effective spending of AU$2·3 million could eradicate all non-native plant species from the only threatened ecological community within the Lake Eyre Basin, the Great Artesian Basin discharge springs. Synthesis and applications. Our framework, based on a case study of the ˜120 million ha Lake Eyre Basin in Australia, provides a rationale for financially efficient investment in non-native plant management and reveals combinations of strategies that are optimal for different budgets. It also highlights knowledge gaps and incidental findings that could improve effective management of non-native plants, for example addressing the reliability of species distribution data and prevalence of information sharing across states and regions.
Resumo:
The digital divide is the disparancy in access to information, in the ability to communicate, and in the capacity to make information and communication serve full participation in the information society. Indeed, the conversation about the digital divide has developed over the last decade from a focus on connectivity and access to information and communication technologies, to a conversation that encompasses the ability to use them and to the utility that usage provides (Wei et al., 2011). However, this conversation, while transitioning from technology to the skills of the people that use them and to the fruits of their use is limited in its ability to take into account the social role of information and communication technologies (ICTs). One successful attempt in conceptualizing the social impact of the differences in access to and utilization of digital communication technologies, was developed by van Dijk (2005) whose sequential model for analyzing the divide states that: 1. Categorical inequalities in society produce an unequal distribution of resources; 2. An unequal distribution of resources causes unequal access to digital technologies; 3. Unequal access to digital technologies also depends on the characteristics of these technologies; 4. Unequal access to digital technologies brings about unequal participation in society; 5. Unequal participation in society reinforces categorical inequalities and unequal distributions of resources.” (p. 15) As van Dijk’s model demonstrates, the divide’s impact is the exclusion of individuals from participation. Still left to be defined are the “categorical inequalities,” the “resources,” the “characteristics of digital technologies,” and the different levels of “access” that result in differentiated levels of participation, as these change over time due to the evolving nature of technology and the dynamics of society. And most importantly, the meaning of “participation” in contemporary society needs to be determined as it is differentiated levels of participation that are the result of the divide and the engine of the ever-growing disparities. Our argument is structured in the following manner: We first claim that contemporary digital media differ from the previous generation of ICTs along four dimensions: They offer an abundance of information resources and communication channels when compared to the relative paucity of both in the past; they offer mobility as opposed to the stationary nature of their predecessors; they are interactive in that they provide users with the capability to design their own media environments in contrast to the dictated environs of previous architectures; and, they allow users to communicate utilizing multi forms of mediation, unlike the uniformity of sound or word that limited users in the past. We then submit that involvement in the information society calls for egalitarian access to all four dimensions of the user experience that make contemporary media different from their predecessors and that the ability to experience all four affects the levels in which humans partake in the shaping of society. The model being cyclical, we then discuss how lower levels of participation contribute to the enhancement of social inequalities. Finally, we discuss why participation is needed in order to achieve full membership in the information society and what political philosophy should govern policy solutions targeting the re-inclusion of those digitally excluded.
Resumo:
This constructivist grounded theory study investigated the nature of new mothers' information experience in social media. The findings provide a holistic view of the phenomenon and the resultant substantive grounded theory describes new mothers' information experience in social media as a complex, multi-layered, and highly contextualised phenomenon. It encapsulates multiple individual experiences of information, and is broader and deeper than the individual experiences it is comprised of. The theory incorporates the characteristics, dimensions and categories of experience to provide a holistic view of new mothers' information experience in social media.
Resumo:
In his 1987 book, The Media Lab: Inventing the Future at MIT, Stewart Brand provides an insight into the visions of the future of the media in the 1970s and 1980s. 1 He notes that Nicolas Negroponte made a compelling case for the foundation of a media laboratory at MIT with diagrams detailing the convergence of three sectors of the media—the broadcast and motion picture industry; the print and publishing industry; and the computer industry. Stewart Brand commented: ‘If Negroponte was right and communications technologies really are converging, you would look for signs that technological homogenisation was dissolving old boundaries out of existence, and you would expect an explosion of new media where those boundaries used to be’. Two decades later, technology developers, media analysts and lawyers have become excited about the latest phase of media convergence. In 2006, the faddish Time Magazine heralded the arrival of various Web 2.0 social networking services: You can learn more about how Americans live just by looking at the backgrounds of YouTube videos—those rumpled bedrooms and toy‐strewn basement rec rooms—than you could from 1,000 hours of network television. And we didn’t just watch, we also worked. Like crazy. We made Facebook profiles and Second Life avatars and reviewed books at Amazon and recorded podcasts. We blogged about our candidates losing and wrote songs about getting dumped. We camcordered bombing runs and built open‐source software. America loves its solitary geniuses—its Einsteins, its Edisons, its Jobses—but those lonely dreamers may have to learn to play with others. Car companies are running open design contests. Reuters is carrying blog postings alongside its regular news feed. Microsoft is working overtime to fend off user‐created Linux. We’re looking at an explosion of productivity and innovation, and it’s just getting started, as millions of minds that would otherwise have drowned in obscurity get backhauled into the global intellectual economy. The magazine announced that Time’s Person of the Year was ‘You’, the everyman and everywoman consumer ‘for seizing the reins of the global media, for founding and framing the new digital democracy, for working for nothing and beating the pros at their own game’. This review essay considers three recent books, which have explored the legal dimensions of new media. In contrast to the unbridled exuberance of Time Magazine, this series of legal works displays an anxious trepidation about the legal ramifications associated with the rise of social networking services. In his tour de force, The Future of Reputation: Gossip, Rumor, and Privacy on the Internet, Daniel Solove considers the implications of social networking services, such as Facebook and YouTube, for the legal protection of reputation under privacy law and defamation law. Andrew Kenyon’s edited collection, TV Futures: Digital Television Policy in Australia, explores the intersection between media law and copyright law in the regulation of digital television and Internet videos. In The Future of the Internet and How to Stop It, Jonathan Zittrain explores the impact of ‘generative’ technologies and ‘tethered applications’—considering everything from the Apple Mac and the iPhone to the One Laptop per Child programme.
Resumo:
Driven by a desire to redevelop derelict land, attract inward investments, and better exploit the commercial potential of local talent, public authorities in Glasgow are partnering with private developers to transform an abandoned industrial dockland into a riverside business cluster for the creative industries. It’s a strategy increasingly common in a number of other peripheral regions and it highlights the new role “creativity” plays in urban rejuvenation, social renewal, and economic development. At its core, the strategy also betrays a troubling policy shift away from certain democratic conceptions of culture to ones that are more attuned to economic considerations shaped by global influences.
Resumo:
In November 2010, tension between Internet infrastructure companies boiled over in a dispute between content distribution network (CDN) Level 3 and Internet service provider (ISP) Comcast. Level 3, a distribution partner of Netflix, accused Comcast of violating the principles of net neutrality when the ISP increased distribution fees for carrying high bandwidth services. Comcast justified its actions by stating that the price increase was standard practice and argued Level 3 was trying to avoid paying its fair share. The dispute exemplifies the growing concern over the rising costs of streaming media services. The companies facing these inflated infrastructure costs are CDNs (Level 3, Equinix, Limelight, Akamai, and Voxel), companies that host streaming media content on server farms and distribute the content to a variety of carriers, and ISPs (Comcast, Time Warner, Cox, and AT&T), the cable and phone companies that provide “last mile” service to paying customers. Both CDNs and ISPs are lobbying government regulators to keep their costs at a minimum. The outcome of these disputes will influence the cost, quality, and legal status of streaming media.