983 resultados para 100509 Video Communications


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Efficient and effective feature detection and representation is an important consideration when processing videos, and a large number of applications such as motion analysis, 3D scene understanding, tracking etc. depend on this. Amongst several feature description methods, local features are becoming increasingly popular for representing videos because of their simplicity and efficiency. While they achieve state-of-the-art performance with low computational complexity, their performance is still too limited for real world applications. Furthermore, rapid increases in the uptake of mobile devices has increased the demand for algorithms that can run with reduced memory and computational requirements. In this paper we propose a semi binary based feature detectordescriptor based on the BRISK detector, which can detect and represent videos with significantly reduced computational requirements, while achieving comparable performance to the state of the art spatio-temporal feature descriptors. First, the BRISK feature detector is applied on a frame by frame basis to detect interest points, then the detected key points are compared against consecutive frames for significant motion. Key points with significant motion are encoded with the BRISK descriptor in the spatial domain and Motion Boundary Histogram in the temporal domain. This descriptor is not only lightweight but also has lower memory requirements because of the binary nature of the BRISK descriptor, allowing the possibility of applications using hand held devices.We evaluate the combination of detectordescriptor performance in the context of action classification with a standard, popular bag-of-features with SVM framework. Experiments are carried out on two popular datasets with varying complexity and we demonstrate comparable performance with other descriptors with reduced computational complexity.

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Quality of experience (QoE) measures the overall perceived quality of mobile video delivery from subjective user experience and objective system performance. Current QoE computing models have two main limitations: 1) insufficient consideration of the factors influencing QoE, and; 2) limited studies on QoE models for acceptability prediction. In this paper, a set of novel acceptability-based QoE models, denoted as A-QoE, is proposed based on the results of comprehensive user studies on subjective quality acceptance assessments. The models are able to predict users’ acceptability and pleasantness in various mobile video usage scenarios. Statistical regression analysis has been used to build the models with a group of influencing factors as independent predictors, including encoding parameters and bitrate, video content characteristics, and mobile device display resolution. The performance of the proposed A-QoE models has been compared with three well-known objective Video Quality Assessment metrics: PSNR, SSIM and VQM. The proposed A-QoE models have high prediction accuracy and usage flexibility. Future user-centred mobile video delivery systems can benefit from applying the proposed QoE-based management to optimize video coding and quality delivery decisions.

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Recent modelling of socio-economic costs by the Australian railway industry in 2010 has estimated the cost of level crossing accidents to exceed AU$116 million annually. To better understand causal factors that contribute to these accidents, the Cooperative Research Centre for Rail Innovation is running a project entitled Baseline Level Crossing Video. The project aims to improve the recording of level crossing safety data by developing an intelligent system capable of detecting near-miss incidents and capturing quantitative data around these incidents. To detect near-miss events at railway level crossings a video analytics module is being developed to analyse video footage obtained from forward-facing cameras installed on trains. This paper presents a vision base approach for the detection of these near-miss events. The video analytics module is comprised of object detectors and a rail detection algorithm, allowing the distance between a detected object and the rail to be determined. An existing publicly available Histograms of Oriented Gradients (HOG) based object detector algorithm is used to detect various types of vehicles in each video frame. As vehicles are usually seen from a sideway view from the cabin’s perspective, the results of the vehicle detector are verified using an algorithm that can detect the wheels of each detected vehicle. Rail detection is facilitated using a projective transformation of the video, such that the forward-facing view becomes a bird’s eye view. Line Segment Detector is employed as the feature extractor and a sliding window approach is developed to track a pair of rails. Localisation of the vehicles is done by projecting the results of the vehicle and rail detectors on the ground plane allowing the distance between the vehicle and rail to be calculated. The resultant vehicle positions and distance are logged to a database for further analysis. We present preliminary results regarding the performance of a prototype video analytics module on a data set of videos containing more than 30 different railway level crossings. The video data is captured from a journey of a train that has passed through these level crossings.

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Much of what is written about digital technologies in preschool contexts focuses on young children’s acquisition of skills rather than their meaning-making during use of technologies. In this paper, we consider how the viewing of a YouTube video was used by a teacher and children to produce shared understandings about it. Conversation analysis of talk and interaction during the viewing of the video establishes some of the ways that individual accounts of events were produced for others and then endorsed as shared understandings. The analysis establishes how adults and children made use of verbal and embodied actions during interactions to produce shared understandings of the YouTube video, the events it recorded and written commentary about those events

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This is the first volume in a book series examining how organizations in the creative industries respond to disruptive change and how they themselves generate business innovations. The aspiration of this book series is to understand some of the common forces behind the disruptions occurring in so many creative industries today and identifying the most promising strategies and responses by organizations to create new value propositions, business models and business practices that can enable these industry participants to cope with and eventually thrive as their industries and sectors are transformed. The chapters included in the volume examine the processes of disruption and transformation due to the technology of the Internet, social forces driven by social media, the development of new portable digital devices with greater capabilities and smaller size, the decreasing costs of new information, and the creation of new business models and forms of intellectual property ownership rights for a digitized industry. The context for this volume is the publishing industries, understood as the industries for the publishing of fiction and non-fiction books, academic literature, consumer as well as trade magazines, and daily newspapers. This volume includes chapters by an internationally diverse array of media scholars whose chapters provide insights into these phenomena in Eastern Europe, Finland, France, Germany, Norway, Portugal, Russia, and the United States, using different methodological frameworks including, but not limited to, surveys, in-depth interviews and multiple-case studies. One gap that this book series seeks to fill is that between the study of business innovation and disruption by innovation scholars largely based in business school settings and similar studies by scholarly experts from non-business school disciplines, including the broader social sciences (e.g. sociology, political science, economic geography) and creative industry based professional school disciplines (e.g. architecture, communications, design, film making, journalism, media studies, performing arts, photography and television). Future volumes of this book series will examine disruption and business innovation in the film, video and photography sectors (volume two), the music sector (volume three) and interactive entertainment (volume four), with subsequent volumes focusing on the most relevant developments in creative industry business innovation and disruption that emerge.

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This column features a conversation (via email, image sharing, and Facetime) that took place over several months between two international theorists of digital filmmaking from schools in two countries—Professors Jason Ranker (Portland State University, Oregon, United States) and Kathy Mills (Queensland University of Technology, Australia). The authors discuss emerging ways of thinking about video making, sharing tips and anecdotes from classroom experience to inspire teachers to explore with adolescents the meaning potentials of digital video creation. The authors briefly discuss their previous work in this area, and then move into a discussion of how the material spaces in which students create videos profoundly shape the films' meanings and significance. The article ends with a discussion of how students can take up creative new directions, pushing the boundaries of the potentials of classroom video making and uncovering profound uses of the medium.

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A simple but accurate method for measuring the Earth’s radius using a video camera is described. A video camera was used to capture a shadow rising up the wall of a tall building at sunset. A free program called ImageJ was used to measure the time it took the shadow to rise a known distance up the building. The time, distance and length of the sidereal day were used to calculate the radius of the Earth. The radius was measured as 6394.3 +/- 118 km, which is within 1.8% of the accepted average value of 6371 km and well within the experimental error. The experiment is suitable as a high school or university project and should produce a value for Earth’s radius within a few per cent at latitudes towards the equator, where at some times of the year the ecliptic is approximately normal to the horizon.

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This is the fourth edition of New Media: An Introduction, with the previous editions being published by Oxford University Press in 2002, 2005 and 2008. As the first edition of the book published in the 2010s, every chapter has been comprehensively revised, and there are new chapters on: • Online News and the Future of Journalism (Chapter 7) • New Media and the Transformation of Higher Education (Chapter 10) • Online Activism and Networked Politics (Chapter 12). It has retained popular features of the third edition, including the twenty key concepts in new media (Chapter 2) and illustrative case studies to assist with teaching new media. The case studies in the book cover: the global internet; Wikipedia; transmedia storytelling; Media Studies 2.0; the games industry and exploitation; video games and violence; WikiLeaks; the innovator’s dilemma; massive open online courses (MOOCs); Creative Commons; the Barack Obama Presidential campaigns; and the Arab Spring. Several major changes in the media environment since the publication of the third edition stand out. Of particular importance has been the rise of social media platforms such as Facebook, Twitter and YouTube, which draw out even more strongly the features of the internet as networked and participatory media, with a range of implications across the economy, society and culture. In addition, the political implications of new media have become more apparent with a range of social media-based political campaigns, from Barack Obama’s successful Presidential election campaigns to the Occupy movements and the Arab Spring. At the same time, the subsequent developments of politics in these and other cases has drawn attention to the limitations of thinking about the politics or the public sphere in technologically determinist ways. When the first edition of New Media was published in 2002, the concept of new media was seen as being largely about the internet as it was accessed from personal computers. The subsequent decade has seen a proliferation of platforms and devices: we now access media in all forms from our phones and other mobile platforms, therefore we seen television and the internet increasingly converging, and we see a growing uncoupling of digital media content and delivery platforms. While this has a range of implications for media law and policy, from convergent media policy to copyright reform, governments and policy-makers are struggling to adapt to such seismic shifts from mass communications media to convergent social media. The internet is no longer primarily a Western-based medium. Two-thirds of the world’s internet users are now outside of Europe and North America; three-quarters of internet users use languages other than English; and three-quarters of the world’s mobile cellular phone subscriptions are in developing nations. It is also apparent that conducting discussions about how to develop new media technologies and discussions about their cultural and creative content can no longer be separated. Discussions of broadband strategies and the knowledge economy need to be increasingly joined with those concerning the creative industries and the creative economy.

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Video stimulated recall interviewing is a research technique in which subjects view a video sequence of their behaviour and are then invited to reflect on their decision-making processes during the videoed event. Despite its popularity, this technique raises methodological issues for researchers, particularly novice researchers in education. The paper reports that while stimulated recall is a valuable technique for investigating decision making processes in relation to specific events, it is not a technique that lends itself as a universal technique for research. This paper recounts one study in educational research where stimulated recall interview was used successfully as a useful tool for collecting data with an adapted version of SRI procedure.

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In this paper, the problem of moving object detection in aerial video is addressed. While motion cues have been extensively exploited in the literature, how to use spatial information is still an open problem. To deal with this issue, we propose a novel hierarchical moving target detection method based on spatiotemporal saliency. Temporal saliency is used to get a coarse segmentation, and spatial saliency is extracted to obtain the object’s appearance details in candidate motion regions. Finally, by combining temporal and spatial saliency information, we can get refined detection results. Additionally, in order to give a full description of the object distribution, spatial saliency is detected in both pixel and region levels based on local contrast. Experiments conducted on the VIVID dataset show that the proposed method is efficient and accurate.

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This paper discusses the idea and demonstrates an early prototype of a novel method of interacting with security surveillance footage using natural user interfaces in place of traditional mouse and keyboard interaction. Current surveillance monitoring stations and systems provide the user with a vast array of video feeds from multiple locations on a video wall, relying on the user’s ability to distinguish locations of the live feeds from experience or list based key-value pair of location and camera IDs. During an incident, this current method of interaction may cause the user to spend increased amounts time obtaining situational and location awareness, which is counter-productive. The system proposed in this paper demonstrates how a multi-touch screen and natural interaction can enable the surveillance monitoring station users to quickly identify the location of a security camera and efficiently respond to an incident.

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In this paper, an integrated inter-vehicles wireless communications and positioning system supporting alternate positioning techniques is proposed to meet the requirements of safety applications of Cooperative Intelligent Transportation Systems (C-ITS). Recent advances have repeatedly demonstrated that road safety problems can be to a large extent addressed via a range of technologies including wireless communications and positioning in vehicular environments. The novel communication stack utilizing a dedicated frequency spectrum (e.g. at 5.9 GHz band), known as Dedicated Short-Range Communications (DSRC), has been particularly designed for Wireless Access in Vehicular Environments (WAVE) to support safety applications in highly dynamic environments. Global Navigation Satellite Systems (GNSS) is another essential enabler to support safety on rail and roads. Although current vehicle navigation systems such as single frequency Global Positioning System (GPS) receivers can provide route guidance with 5-10 meters (road-level) position accuracy, positioning systems utilized in C-ITS must provide position solutions with lane-level and even in-lane-level accuracies based on the requirements of safety applications. This article reviews the issues and technical approaches that are involved in designing a vehicular safety communications and positioning architecture; it also provides technological solutions to further improve vehicular safety by integrating the DSRC and GNSS-based positioning technologies.

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The most widely used introduction to the Australian media, fully updated to reflect the increasing prominence of the internet in the communication and entertainment industries. Description Traditional media are being reshaped by digital technologies. The funding model for quality journalism has been undermined by the drift of advertising online, demarcations between different forms of media are rapidly fading, and audiences have fragmented. We can catch up with our favourite TV show on a tablet, social media can be more important than mainstream radio in a crisis, and organisations large and small have become publishers in their own right on apps. Nevertheless mainstream media remain powerful. The Media and Communications in Australia offers a systematic introduction to this dynamic field. Fully updated and revised to take account of recent developments, this fourth edition outlines the key media industries and explains how communications technologies are impacting on them. It provides a thorough overview of the main approaches taken in studying the media, and includes an expanded 'issues' section with new chapters on social media, gaming, apps, the environment, media regulation, ethics and privacy. With contributions from some of Australia's best researchers and teachers in the field, The Media and Communications in Australia remains the most comprehensive and reliable introduction to media and communications available. It is an ideal student text, and a reference for teachers of media and anyone interested in this influential industry.

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This research has analysed both reciprocity and feedback mechanisms in multi-antenna wireless systems. It has presented the basis of an effective CSI feedback mechanism that efficiently provides the transmitter with the minimum information to allow the accurate knowledge of a rapidly changing channel. The simulations have been conducted using MATLAB to measure the improvement when the channel is estimated at the receiver in a 2 X 2 multi-antenna system and compared to the case of perfect channel knowledge at the receiver.

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Importance Active video games may offer an effective strategy to increase physical activity in overweight and obese children. However, the specific effects of active gaming when delivered within the context of a pediatric weight management program are unknown. Objective To evaluate the effects of active video gaming on physical activity and weight loss in children participating in an evidence-based weight management program delivered in the community. Design, Setting, and Participants Group-randomized clinical trial conducted during a 16-week period in YMCAs and schools located in Massachusetts, Rhode Island, and Texas. Seventy-five overweight or obese children (41 girls [55%], 34 whites [45%], 20 Hispanics [27%], and 17 blacks [23%]) enrolled in a community-based pediatric weight management program. Mean (SD) age of the participants was 10.0 (1.7) years; body mass index (BMI) z score, 2.15 (0.40); and percentage overweight from the median BMI for age and sex, 64.3% (19.9%). Interventions All participants received a comprehensive family-based pediatric weight management program (JOIN for ME). Participants in the program and active gaming group received hardware consisting of a game console and motion capture device and 1 active game at their second treatment session and a second game in week 9 of the program. Participants in the program-only group were given the hardware and 2 games at the completion of the 16-week program. Main Outcomes and Measures Objectively measured daily moderate-to-vigorous and vigorous physical activity, percentage overweight, and BMI z score. Results Participants in the program and active gaming group exhibited significant increases in moderate-to-vigorous (mean [SD], 7.4 [2.7] min/d) and vigorous (2.8 [0.9] min/d) physical activity at week 16 (P < .05). In the program-only group, a decline or no change was observed in the moderate-to-vigorous (mean [SD] net difference, 8.0 [3.8] min/d; P = .04) and vigorous (3.1 [1.3] min/d; P = .02) physical activity. Participants in both groups exhibited significant reductions in percentage overweight and BMI z scores at week 16. However, the program and active gaming group exhibited significantly greater reductions in percentage overweight (mean [SD], −10.9% [1.6%] vs −5.5% [1.5%]; P = .02) and BMI z score (−0.25 [0.03] vs −0.11 [0.03]; P < .001). Conclusions and Relevance Incorporating active video gaming into an evidence-based pediatric weight management program has positive effects on physical activity and relative weight.