WorldWideScience

Sample records for video streaming experience

  1. Students' Experiences with Live Video-Streamed Teaching Classes

    DEFF Research Database (Denmark)

    Jelsbak, Vibe Alopaeus; Buus, Lillian; Thorsen, Jonas

    2017-01-01

    Students' Experiences with Live Video-Streamed Classes The bachelor programme in biomedical laboratory technology at VIA Faculty of Health Sciences offers a combination of live video-streamed and traditional teaching. It is the student’s individual choice whether to attend classes on......-site or to attend classes from home via live video-stream. Our previous studies revealed that interaction and dialog between attendants were reduced in the live-streamed sessions compared to on-site teaching, and that the main reasons were technological issues and the teacher’s choice of teaching methods. One......-site and live video-streamed teaching. The results document a continuous progress in technological transparency, as the live video-streamed classes increasingly support the student’s flexibility in ways of attending and interacting in classes. Interaction is facilitated through teacher driven support, resulting...

  2. The Students Experiences With Live Video-Streamed Teaching Classes

    DEFF Research Database (Denmark)

    Jelsbak, Vibe Alopaeus; Ørngreen, Rikke; Buus, Lillian

    2017-01-01

    The Bachelor's Degree Programme of Biomedical Laboratory Science at VIA Faculty of Health Sciences offers a combination of live video-streamed and traditional teaching. It is the student’s individual choice whether to attend classes on-site or to attend classes from home via live video-stream. Our...... method inspired from mobile probes (Ørngreen & Jørgensen, n.d.). The research results document a continuous progress in technological transparency, as the live video-streamed classes increasingly support the student’s flexibility in ways of attending and interacting in classes. The analysis shows...... transparency in the live video-streamed teaching sessions during a 5-year period of continuous development of technological and pedagogical solutions for live-streamed teaching. Data describing student’s experiences were gathered in a longitudinal study of four sessions from 2012 to 2017 using a qualitative...

  3. Students' Experiences with Live Video-Streamed Teaching Classes

    DEFF Research Database (Denmark)

    Jelsbak, Vibe Alopaeus; Buus, Lillian; Thorsen, Jonas

    2017-01-01

    -site and live video-streamed teaching. The results document a continuous progress in technological transparency, as the live video-streamed classes increasingly support the student’s flexibility in ways of attending and interacting in classes. Interaction is facilitated through teacher driven support, resulting...

  4. Video Streaming of Lectures via the Internet: An Experience.

    Science.gov (United States)

    McCrohon, Mark; Lo, Victor; Dang, Jim; Johnston, Carol

    This paper reports on an investigation into methods of efficiently introducing video streaming into subjects in the economics and commerce faculty at the University of Melbourne (Australia). Several software options were investigated before finally settling on RealSystems. The paper provides a brief review of the background of the project followed…

  5. User aware video streaming

    Science.gov (United States)

    Kerofsky, Louis; Jagannath, Abhijith; Reznik, Yuriy

    2015-03-01

    We describe the design of a video streaming system using adaptation to viewing conditions to reduce the bitrate needed for delivery of video content. A visual model is used to determine sufficient resolution needed under various viewing conditions. Sensors on a mobile device estimate properties of the viewing conditions, particularly the distance to the viewer. We leverage the framework of existing adaptive bitrate streaming systems such as HLS, Smooth Streaming or MPEG-DASH. The client rate selection logic is modified to include a sufficient resolution computed using the visual model and the estimated viewing conditions. Our experiments demonstrate significant bitrate savings compare to conventional streaming methods which do not exploit viewing conditions.

  6. On subjective quality assessment of adaptive video streaming via crowdsourcing and laboratory based experiments

    DEFF Research Database (Denmark)

    Søgaard, Jacob; Shahid, Muhammad; Pokhrel, Jeevan

    2017-01-01

    Video streaming services are offered over the Internet and since the service providers do not have full control over the network conditions all the way to the end user, streaming technologies have been developed to maintain the quality of service in these varying network conditions i.e. so called...... adaptive video streaming. In order to cater for users' Quality of Experience (QoE) requirements, HTTP based adaptive streaming solutions of video services have become popular. However, the keys to ensure the users a good QoE with this technology is still not completely understood. User QoE feedback...

  7. Accessing and Engaging with Video Streams for Educational Purposes: Experiences, Issues and Concerns

    Science.gov (United States)

    Bracher, Maggie; Collier, Richard; Ottewill, Roger; Shephard, Kerry

    2005-01-01

    Video streaming has the potential to offer tutors a more flexible and accessible means of incorporating moving images into learning resources for their students than conventional video. Consideration is given to this assertion by drawing upon the experiences of staff and evidence from students at the University of Southampton in the use of a…

  8. High Definition Video Streaming Using H.264 Video Compression

    OpenAIRE

    Bechqito, Yassine

    2009-01-01

    This thesis presents high definition video streaming using H.264 codec implementation. The experiment carried out in this study was done for an offline streaming video but a model for live high definition streaming is introduced, as well. Prior to the actual experiment, this study describes digital media streaming. Also, the different technologies involved in video streaming are covered. These include streaming architecture and a brief overview on H.264 codec as well as high definition t...

  9. Video streaming into the mainstream.

    Science.gov (United States)

    Garrison, W

    2001-12-01

    Changes in Internet technology are making possible the delivery of a richer mixture of media through data streaming. High-quality, dynamic content, such as video and audio, can be incorporated into Websites simply, flexibly and interactively. Technologies such as G3 mobile communication, ADSL, cable and satellites enable new ways of delivering medical services, information and learning. Systems such as Quicktime, Windows Media and Real Video provide reliable data streams as video-on-demand and users can tailor the experience to their own interests. The Learning Development Centre at the University of Portsmouth have used streaming technologies together with e-learning tools such as dynamic HTML, Flash, 3D objects and online assessment successfully to deliver on-line course content in economics and earth science. The Lifesign project--to develop, catalogue and stream health sciences media for teaching--is described and future medical applications are discussed.

  10. Streaming-video produktion

    DEFF Research Database (Denmark)

    Grønkjær, Poul

    2004-01-01

     E-learning Lab på Aalborg Universitet har i forbindelse med forskningsprojektet Virtuelle Læringsformer og Læringsmiljøer foretaget en række praktiske eksperimenter med streaming-video produktioner. Hensigten med denne artikel er at formidle disse erfaringer. Artiklen beskriver hele produktionsf...... E-learning Lab på Aalborg Universitet har i forbindelse med forskningsprojektet Virtuelle Læringsformer og Læringsmiljøer foretaget en række praktiske eksperimenter med streaming-video produktioner. Hensigten med denne artikel er at formidle disse erfaringer. Artiklen beskriver hele...... produktionsforløbet: fra ide til færdigt produkt, forskellige typer af præsentationer, dramaturgiske overvejelser samt en konceptskitse. Streaming-video teknologien er nu så udviklet med et så tilfredsstillende audiovisuelt udtryk at vi kan begynde at fokusere på, hvilket indhold der er velegnet til at blive gjort...... tilgængeligt uafhængigt af tid og sted. Afslutningsvis er der en række kildehenvisninger, blandt andet en oversigt over de streaming-video produktioner, som denne artikel bygger på....

  11. We All Stream for Video

    Science.gov (United States)

    Technology & Learning, 2008

    2008-01-01

    More than ever, teachers are using digital video to enhance their lessons. In fact, the number of schools using video streaming increased from 30 percent to 45 percent between 2004 and 2006, according to Market Data Retrieval. Why the popularity? For starters, video-streaming products are easy to use. They allow teachers to punctuate lessons with…

  12. Video Streaming in Online Learning

    Science.gov (United States)

    Hartsell, Taralynn; Yuen, Steve Chi-Yin

    2006-01-01

    The use of video in teaching and learning is a common practice in education today. As learning online becomes more of a common practice in education, streaming video and audio will play a bigger role in delivering course materials to online learners. This form of technology brings courses alive by allowing online learners to use their visual and…

  13. Quality scalable video data stream

    OpenAIRE

    Wiegand, T.; Kirchhoffer, H.; Schwarz, H

    2008-01-01

    An apparatus for generating a quality-scalable video data stream (36) is described which comprises means (42) for coding a video signal (18) using block-wise transformation to obtain transform blocks (146, 148) of transformation coefficient values for a picture (140) of the video signal, a predetermined scan order (154, 156, 164, 166) with possible scan positions being defined among the transformation coefficient values within the transform blocks so that in each transform block, for each pos...

  14. Electronic Eye: Streaming Video On-Demand.

    Science.gov (United States)

    Meulen, Kathleen

    2002-01-01

    Discusses the use of on-demand streaming video in school libraries. Explains how streaming works, considers advantages and technical issues, and describes products from three companies that are pioneering streaming in the educational video market. (LRW)

  15. Android Video Streaming

    Science.gov (United States)

    2014-05-01

    be processed by a nearby high -performance computing asset and returned to a squad of Soldiers with annotations indicating the location of friendly and...is to change the resolution, bitrate, and/or framerate of the video being transmitted to the client, reducing the bandwidth requirements of the...video. This solution is typically not viable because a progressive download is required to have a constant resolution, bitrate, and framerate because

  16. Robust Watermarking of Video Streams

    Directory of Open Access Journals (Sweden)

    T. Polyák

    2006-01-01

    Full Text Available In the past few years there has been an explosion in the use of digital video data. Many people have personal computers at home, and with the help of the Internet users can easily share video files on their computer. This makes possible the unauthorized use of digital media, and without adequate protection systems the authors and distributors have no means to prevent it.Digital watermarking techniques can help these systems to be more effective by embedding secret data right into the video stream. This makes minor changes in the frames of the video, but these changes are almost imperceptible to the human visual system. The embedded information can involve copyright data, access control etc. A robust watermark is resistant to various distortions of the video, so it cannot be removed without affecting the quality of the host medium. In this paper I propose a video watermarking scheme that fulfills the requirements of a robust watermark. 

  17. Smart Streaming for Online Video Services

    OpenAIRE

    Chen, Liang; Zhou, Yipeng; Chiu, Dah Ming

    2013-01-01

    Bandwidth consumption is a significant concern for online video service providers. Practical video streaming systems usually use some form of HTTP streaming (progressive download) to let users download the video at a faster rate than the video bitrate. Since users may quit before viewing the complete video, however, much of the downloaded video will be "wasted". To the extent that users' departure behavior can be predicted, we develop smart streaming that can be used to improve user QoE with ...

  18. Maximizing Resource Utilization in Video Streaming Systems

    Science.gov (United States)

    Alsmirat, Mohammad Abdullah

    2013-01-01

    Video streaming has recently grown dramatically in popularity over the Internet, Cable TV, and wire-less networks. Because of the resource demanding nature of video streaming applications, maximizing resource utilization in any video streaming system is a key factor to increase the scalability and decrease the cost of the system. Resources to…

  19. ADAPTIVE STREAMING OVER HTTP (DASH UNTUK APLIKASI VIDEO STREAMING

    Directory of Open Access Journals (Sweden)

    I Made Oka Widyantara

    2015-12-01

    Full Text Available This paper aims to analyze Internet-based streaming video service in the communication media with variable bit rates. The proposed scheme on Dynamic Adaptive Streaming over HTTP (DASH using the internet network that adapts to the protocol Hyper Text Transfer Protocol (HTTP. DASH technology allows a video in the video segmentation into several packages that will distreamingkan. DASH initial stage is to compress the video source to lower the bit rate video codec uses H.26. Video compressed further in the segmentation using MP4Box generates streaming packets with the specified duration. These packages are assembled into packets in a streaming media format Presentation Description (MPD or known as MPEG-DASH. Streaming video format MPEG-DASH run on a platform with the player bitdash teritegrasi bitcoin. With this scheme, the video will have several variants of the bit rates that gave rise to the concept of scalability of streaming video services on the client side. The main target of the mechanism is smooth the MPEG-DASH streaming video display on the client. The simulation results show that the scheme based scalable video streaming MPEG-DASH able to improve the quality of image display on the client side, where the procedure bufering videos can be made constant and fine for the duration of video views

  20. Apples to Oranges: Comparing Streaming Video Platforms

    OpenAIRE

    Milewski, Steven; Threatt, Monique

    2017-01-01

    Librarians rely on an ever-increasing variety of platforms to deliver streaming video content to our patrons. These two presentations will examine different aspects of video streaming platforms to gain guidance from the comparison of platforms. The first will examine the accessibility compliance of the various video streaming platforms for users with disabilities by examining accessibility features of the platforms. The second will be a comparison of subject usage of two of the larger video s...

  1. Introducing VAST: a Video-Audio Streaming Tester

    Directory of Open Access Journals (Sweden)

    Adrian Sterca

    2010-09-01

    Full Text Available We present a testing package aimed at video and audio streaming across best-effort networks like the Internet. VAST is intended to be a testing framework for protocols transporting audio-video streams across IP networks. It offers the simplicity and predictability of deterministic simulators like ns-2 combined with the testing power of real-world experiments.

  2. Video streaming: implementation and evaluation in an undergraduate nursing program.

    Science.gov (United States)

    Bennett, Paul N; Glover, Pauline

    2008-02-01

    Video streaming technology enables video content, held on the web sites, to be streamed via the web. We report the implementation and evaluation of video streaming in an undergraduate nursing program in a metropolitan university in Australia. Students (n=703) were emailed a survey with a 15% response rate. We found that 91% (n=74) of respondents stated that video streaming assisted their learning. Forty-six percent(n=50) of students had difficulty accessing video streaming (particularly at the beginning of the study period). Over a 97-day period there were 8440 "hits" to the site from 1039 different internet protocol (IP) addresses. There were 4475 video streaming sessions undertaken by users. Video streaming was used for reviewing previously attended lectures (52%, n=56), examination preparation (34%, n=37), viewing missed lectures (27%, n=29) and class preparation (9%, n=10). Our experience with the introduction of video streaming has met with general enthusiasm from both students and teaching staff. Video streaming has particular relevance for rural students.

  3. Streaming Video--The Wave of the Video Future!

    Science.gov (United States)

    Brown, Laura

    2004-01-01

    Videos and DVDs give the teachers more flexibility than slide projectors, filmstrips, and 16mm films but teachers and students are excited about a new technology called streaming. Streaming allows the educators to view videos on demand via the Internet, which works through the transfer of digital media like video, and voice data that is received…

  4. Video Streaming in the Wild West

    OpenAIRE

    Helen Gail Prosser

    2006-01-01

    Northern Lakes College in north-central Alberta is the first post-secondary institution in Canada to use the Media on Demand digital video system to stream large video files between dispersed locations (Karlsen). Staff and students at distant locations of Northern Lakes College are now viewing more than 350 videos using video streaming technology. This has been made possible by SuperNet, a high capacity broadband network that connects schools, hospitals, libraries and government offices thr...

  5. Video streaming in the Wild West

    Directory of Open Access Journals (Sweden)

    Helen Gail Prosser

    2006-11-01

    Full Text Available Northern Lakes College in north-central Alberta is the first post-secondary institution in Canada to use the Media on Demand digital video system to stream large video files between dispersed locations (Karlsen. Staff and students at distant locations of Northern Lakes College are now viewing more than 350 videos using video streaming technology. This has been made possible by SuperNet, a high capacity broadband network that connects schools, hospitals, libraries and government offices throughout the province of Alberta (Alberta SuperNet. This article describes the technical process of implementing video streaming at Northern Lakes College from March 2005 until March 2006.

  6. Research on key technologies in multiview video and interactive multiview video streaming

    OpenAIRE

    Xiu, Xiaoyu

    2011-01-01

    Emerging video applications are being developed where multiple views of a scene are captured. Two central issues in the deployment of future multiview video (MVV) systems are compression efficiency and interactive video experience, which makes it necessary to develop advanced technologies on multiview video coding (MVC) and interactive multiview video streaming (IMVS). The former aims at efficient compression of all MVV data in a ratedistortion (RD) optimal manner by exploiting both temporal ...

  7. Web Audio/Video Streaming Tool

    Science.gov (United States)

    Guruvadoo, Eranna K.

    2003-01-01

    In order to promote NASA-wide educational outreach program to educate and inform the public of space exploration, NASA, at Kennedy Space Center, is seeking efficient ways to add more contents to the web by streaming audio/video files. This project proposes a high level overview of a framework for the creation, management, and scheduling of audio/video assets over the web. To support short-term goals, the prototype of a web-based tool is designed and demonstrated to automate the process of streaming audio/video files. The tool provides web-enabled users interfaces to manage video assets, create publishable schedules of video assets for streaming, and schedule the streaming events. These operations are performed on user-defined and system-derived metadata of audio/video assets stored in a relational database while the assets reside on separate repository. The prototype tool is designed using ColdFusion 5.0.

  8. Comparing Streaming Video and Videotapes: Can Streaming Video Convey Affective Meaning as Well as Videotape?

    Science.gov (United States)

    Cofield, Jay L.

    This study investigated whether or not low-bandwidth streaming video could be useful for affective purposes. A group of 30 students in a cinema course at a public, liberal arts university viewed a 10-minute dramatic video scene by either videotape or low-bandwidth streaming video. They also took a survey to determine their affective responses and…

  9. Streaming Video to Enhance Students' Reflection in Dance Education

    Science.gov (United States)

    Leijen, Ali; Lam, Ineke; Wildschut, Liesbeth; Simons, P. Robert-Jan; Admiraal, Wilfried

    2009-01-01

    This paper presents an evaluation case study that describes the experiences of 15 students and 2 teachers using a video-based learning environment, DiViDU, to facilitate students' daily reflection activities in a composition course and a ballet course. To support dance students' reflection processes streaming video was applied as follows: video…

  10. Crowdsourcing based subjective quality assessment of adaptive video streaming

    DEFF Research Database (Denmark)

    Shahid, M.; Søgaard, Jacob; Pokhrel, J.

    2014-01-01

    humans are considered to be the most valid method of the as- sessment of QoE. Besides lab-based subjective experiments, crowdsourcing based subjective assessment of video quality is gaining popularity as an alternative method. This paper presents insights into a study that investigates perceptual pref......- erences of various adaptive video streaming scenarios through crowdsourcing based subjective quality assessment....

  11. Authentication for Propulsion Test Streaming Video Project

    Data.gov (United States)

    National Aeronautics and Space Administration — An application was developed that could enforce two-factor authentication for NASA access to the Propulsion Test Streaming Video System.  To gain access to the...

  12. Temporal Segmentation of MPEG Video Streams

    Directory of Open Access Journals (Sweden)

    Janko Calic

    2002-06-01

    Full Text Available Many algorithms for temporal video partitioning rely on the analysis of uncompressed video features. Since the information relevant to the partitioning process can be extracted directly from the MPEG compressed stream, higher efficiency can be achieved utilizing information from the MPEG compressed domain. This paper introduces a real-time algorithm for scene change detection that analyses the statistics of the macroblock features extracted directly from the MPEG stream. A method for extraction of the continuous frame difference that transforms the 3D video stream into a 1D curve is presented. This transform is then further employed to extract temporal units within the analysed video sequence. Results of computer simulations are reported.

  13. A Video Streaming Application Using Mobile Media Application Programming Interface

    Directory of Open Access Journals (Sweden)

    Henning Titi Ciptaningtyas

    2010-12-01

    Full Text Available Recently, the development of mobile phone technology is growing rapidly. These developments led to the emerging of a multimedia mobile phone that supports Wireless Local Area Network (WLAN. However, the use of WLAN technology on mobile phones to access the streaming video is very rarely encountered. While the current S60 Symbian operating system as a multimedia mobile phone is very reliable in handling a variety of media such as video.The discussion in this study presents the making of a video streaming application in mobile phone via a WLAN connection using JSR 135 technology or better known as the Mobile Media API (MMAPI. MMAPI is used to control the process of video streaming and its supporting features. The application will use the two protocols namely RTSP and HTTP. Experiment results show that the use of MMAPI on Symbian 60 based mobile phones to do video streaming is feasible and has good reliability. This is indicated by 0% packet loss on a reliable connection. In addition, the times required to play multimedia files are not affected by the size of video streaming files.

  14. Segment scheduling method for reducing 360° video streaming latency

    Science.gov (United States)

    Gudumasu, Srinivas; Asbun, Eduardo; He, Yong; Ye, Yan

    2017-09-01

    360° video is an emerging new format in the media industry enabled by the growing availability of virtual reality devices. It provides the viewer a new sense of presence and immersion. Compared to conventional rectilinear video (2D or 3D), 360° video poses a new and difficult set of engineering challenges on video processing and delivery. Enabling comfortable and immersive user experience requires very high video quality and very low latency, while the large video file size poses a challenge to delivering 360° video in a quality manner at scale. Conventionally, 360° video represented in equirectangular or other projection formats can be encoded as a single standards-compliant bitstream using existing video codecs such as H.264/AVC or H.265/HEVC. Such method usually needs very high bandwidth to provide an immersive user experience. While at the client side, much of such high bandwidth and the computational power used to decode the video are wasted because the user only watches a small portion (i.e., viewport) of the entire picture. Viewport dependent 360°video processing and delivery approaches spend more bandwidth on the viewport than on non-viewports and are therefore able to reduce the overall transmission bandwidth. This paper proposes a dual buffer segment scheduling algorithm for viewport adaptive streaming methods to reduce latency when switching between high quality viewports in 360° video streaming. The approach decouples the scheduling of viewport segments and non-viewport segments to ensure the viewport segment requested matches the latest user head orientation. A base layer buffer stores all lower quality segments, and a viewport buffer stores high quality viewport segments corresponding to the most recent viewer's head orientation. The scheduling scheme determines viewport requesting time based on the buffer status and the head orientation. This paper also discusses how to deploy the proposed scheduling design for various viewport adaptive video

  15. Studi Kualitas Video Streaming Dengan Menggunakan Flexipacket Radio

    OpenAIRE

    Fadly, Auliya

    2014-01-01

    Saat ini sistem komunikasi dengan mengunakan Video Streaming seringkali menjadi alternatif dalam berkomunikasi. Salah satu software pilihan untuk layananan Video Streaming adalah Windows Media Encoder yang dapat dimanfaatkan sebagai software server dan software VLC (VIdeoLAN Client) yang dapat dimanfaatkan sebagai software Client Video Streaming. Terdapat beberapa format Video Streaming yang tersedia di layanan internet seperti FLV, Mp4, AVI dan lain-lain. Pada Tugas Akhir ini dilakukan an...

  16. Enhanced video display and navigation for networked streaming video and networked video playlists

    Science.gov (United States)

    Deshpande, Sachin

    2006-01-01

    In this paper we present an automatic enhanced video display and navigation capability for networked streaming video and networked video playlists. Our proposed method uses Synchronized Multimedia Integration Language (SMIL) as presentation language and Real Time Streaming Protocol (RTSP) as network remote control protocol to automatically generate a "enhanced video strip" display for easy navigation. We propose and describe two approaches - a smart client approach and a smart server approach. We also describe a prototype system implementation of our proposed approach.

  17. Continuity-Aware Scheduling Algorithm for Scalable Video Streaming

    Directory of Open Access Journals (Sweden)

    Atinat Palawan

    2016-05-01

    Full Text Available The consumer demand for retrieving and delivering visual content through consumer electronic devices has increased rapidly in recent years. The quality of video in packet networks is susceptible to certain traffic characteristics: average bandwidth availability, loss, delay and delay variation (jitter. This paper presents a scheduling algorithm that modifies the stream of scalable video to combat jitter. The algorithm provides unequal look-ahead by safeguarding the base layer (without the need for overhead of the scalable video. The results of the experiments show that our scheduling algorithm reduces the number of frames with a violated deadline and significantly improves the continuity of the video stream without compromising the average Y Peek Signal-to-Noise Ratio (PSNR.

  18. Some Effects of Video Streaming on Educational Achievement

    Science.gov (United States)

    Boster, Franklin J.; Meyer, Gary S.; Roberto, Anthony J.; Inge, Carol; Strom, Renee

    2006-01-01

    Although much contemporary thinking leads to the expectation that communication technology, such as video streaming, enhances educational performance on the average, a dearth of strong evidence consistent or inconsistent with this claim precludes a thoughtful evaluation of it. A series of experiments designed to examine this proposition…

  19. Objective video presentation QoE predictor for smart adaptive video streaming

    Science.gov (United States)

    Wang, Zhou; Zeng, Kai; Rehman, Abdul; Yeganeh, Hojatollah; Wang, Shiqi

    2015-09-01

    How to deliver videos to consumers over the network for optimal quality-of-experience (QoE) has been the central goal of modern video delivery services. Surprisingly, regardless of the large volume of videos being delivered everyday through various systems attempting to improve visual QoE, the actual QoE of end consumers is not properly assessed, not to say using QoE as the key factor in making critical decisions at the video hosting, network and receiving sites. Real-world video streaming systems typically use bitrate as the main video presentation quality indicator, but using the same bitrate to encode different video content could result in drastically different visual QoE, which is further affected by the display device and viewing condition of each individual consumer who receives the video. To correct this, we have to put QoE back to the driver's seat and redesign the video delivery systems. To achieve this goal, a major challenge is to find an objective video presentation QoE predictor that is accurate, fast, easy-to-use, display device adaptive, and provides meaningful QoE predictions across resolution and content. We propose to use the newly developed SSIMplus index (https://ece.uwaterloo.ca/~z70wang/research/ssimplus/) for this role. We demonstrate that based on SSIMplus, one can develop a smart adaptive video streaming strategy that leads to much smoother visual QoE impossible to achieve using existing adaptive bitrate video streaming approaches. Furthermore, SSIMplus finds many more applications, in live and file-based quality monitoring, in benchmarking video encoders and transcoders, and in guiding network resource allocations.

  20. An Assessment of Streaming Video In Web-based Instruction.

    Science.gov (United States)

    Cofield, Jay L.

    Streaming video used as an augmentation in Web-based instruction was investigated to: (1) determine if demographic characteristics would lead to significantly different beliefs about the use and perceived effectiveness of streaming video, and (2) whether or not there are characteristics of streaming video that would lead to beliefs about the…

  1. Creating a streaming video collection for your library

    CERN Document Server

    Duncan, Cheryl J

    2014-01-01

    Creating a Streaming Video Collection for Your Library covers the main processes associated with streaming video, from licensing to access and evaluation, and will serve as a key reference and source of best practices for libraries adding streaming video titles to their collections.

  2. Networked telepresence system using web browsers and omni-directional video streams

    Science.gov (United States)

    Ishikawa, Tomoya; Yamazawa, Kazumasa; Sato, Tomokazu; Ikeda, Sei; Nakamura, Yutaka; Fujikawa, Kazutoshi; Sunahara, Hideki; Yokoya, Naokazu

    2005-03-01

    In this paper, we describe a new telepresence system which enables a user to look around a virtualized real world easily in network environments. The proposed system includes omni-directional video viewers on web browsers and allows the user to look around the omni-directional video contents on the web browsers. The omni-directional video viewer is implemented as an Active-X program so that the user can install the viewer automatically only by opening the web site which contains the omni-directional video contents. The system allows many users at different sites to look around the scene just like an interactive TV using a multi-cast protocol without increasing the network traffic. This paper describes the implemented system and the experiments using live and stored video streams. In the experiment with stored video streams, the system uses an omni-directional multi-camera system for video capturing. We can look around high resolution and high quality video contents. In the experiment with live video streams, a car-mounted omni-directional camera acquires omni-directional video streams surrounding the car, running in an outdoor environment. The acquired video streams are transferred to the remote site through the wireless and wired network using multi-cast protocol. We can see the live video contents freely in arbitrary direction. In the both experiments, we have implemented a view-dependent presentation with a head-mounted display (HMD) and a gyro sensor for realizing more rich presence.

  3. Fingerprint multicast in secure video streaming.

    Science.gov (United States)

    Zhao, H Vicky; Liu, K J Ray

    2006-01-01

    Digital fingerprinting is an emerging technology to protect multimedia content from illegal redistribution, where each distributed copy is labeled with unique identification information. In video streaming, huge amount of data have to be transmitted to a large number of users under stringent latency constraints, so the bandwidth-efficient distribution of uniquely fingerprinted copies is crucial. This paper investigates the secure multicast of anticollusion fingerprinted video in streaming applications and analyzes their performance. We first propose a general fingerprint multicast scheme that can be used with most spread spectrum embedding-based multimedia fingerprinting systems. To further improve the bandwidth efficiency, we explore the special structure of the fingerprint design and propose a joint fingerprint design and distribution scheme. From our simulations, the two proposed schemes can reduce the bandwidth requirement by 48% to 87%, depending on the number of users, the characteristics of video sequences, and the network and computation constraints. We also show that under the constraint that all colluders have the same probability of detection, the embedded fingerprints in the two schemes have approximately the same collusion resistance. Finally, we propose a fingerprint drift compensation scheme to improve the quality of the reconstructed sequences at the decoder's side without introducing extra communication overhead.

  4. Quality Adaptive Video Streaming Mechanism Using the Temporal Scalability

    Science.gov (United States)

    Lee, Sunhun; Chung, Kwangsue

    In video streaming applications over the Internet, TCP-friendly rate control schemes are useful for improving network stability and inter-protocol fairness. However, they do not always guarantee a smooth video streaming. To simultaneously satisfy both the network and user requirements, video streaming applications should be quality-adaptive. In this paper, we propose a new quality adaptation mechanism to adjust the quality of congestion-controlled video stream by controlling the frame rate. Based on the current network condition, it controls the frame rate of video stream and the sending rate in a TCP-friendly manner. Through a simulation, we prove that our adaptation mechanism appropriately adjusts the quality of video stream while improving network stability.

  5. Applicability of Existing Objective Metrics of Perceptual Quality for Adaptive Video Streaming

    DEFF Research Database (Denmark)

    Søgaard, Jacob; Krasula, Lukás; Shahid, Muhammad

    2016-01-01

    Objective video quality metrics are designed to estimate the quality of experience of the end user. However, these objective metrics are usually validated with video streams degraded under common distortion types. In the presented work, we analyze the performance of published and known full......-reference and noreference quality metrics in estimating the perceived quality of adaptive bit-rate video streams knowingly out of scope. Experimental results indicate not surprisingly that state of the art objective quality metrics overlook the perceived degradations in the adaptive video streams and perform poorly...... in estimating the subjective quality results....

  6. Layer-based buffer aware rate adaptation design for SHVC video streaming

    Science.gov (United States)

    Gudumasu, Srinivas; Hamza, Ahmed; Asbun, Eduardo; He, Yong; Ye, Yan

    2016-09-01

    This paper proposes a layer based buffer aware rate adaptation design which is able to avoid abrupt video quality fluctuation, reduce re-buffering latency and improve bandwidth utilization when compared to a conventional simulcast based adaptive streaming system. The proposed adaptation design schedules DASH segment requests based on the estimated bandwidth, dependencies among video layers and layer buffer fullness. Scalable HEVC video coding is the latest state-of-art video coding technique that can alleviate various issues caused by simulcast based adaptive video streaming. With scalable coded video streams, the video is encoded once into a number of layers representing different qualities and/or resolutions: a base layer (BL) and one or more enhancement layers (EL), each incrementally enhancing the quality of the lower layers. Such layer based coding structure allows fine granularity rate adaptation for the video streaming applications. Two video streaming use cases are presented in this paper. The first use case is to stream HD SHVC video over a wireless network where available bandwidth varies, and the performance comparison between proposed layer-based streaming approach and conventional simulcast streaming approach is provided. The second use case is to stream 4K/UHD SHVC video over a hybrid access network that consists of a 5G millimeter wave high-speed wireless link and a conventional wired or WiFi network. The simulation results verify that the proposed layer based rate adaptation approach is able to utilize the bandwidth more efficiently. As a result, a more consistent viewing experience with higher quality video content and minimal video quality fluctuations can be presented to the user.

  7. Advanced real-time manipulation of video streams

    CERN Document Server

    Herling, Jan

    2014-01-01

    Diminished Reality is a new fascinating technology that removes real-world content from live video streams. This sensational live video manipulation actually removes real objects and generates a coherent video stream in real-time. Viewers cannot detect modified content. Existing approaches are restricted to moving objects and static or almost static cameras and do not allow real-time manipulation of video content. Jan Herling presents a new and innovative approach for real-time object removal with arbitrary camera movements.

  8. MEKANISME SEGMENTASI LAJU BIT PADA DYNAMIC ADAPTIVE STREAMING OVER HTTP (DASH UNTUK APLIKASI VIDEO STREAMING

    Directory of Open Access Journals (Sweden)

    Muhammad Audy Bazly

    2015-12-01

    Full Text Available This paper aims to analyze Internet-based streaming video service in the communication media with variable bit rates. The proposed scheme on Dynamic Adaptive Streaming over HTTP (DASH using the internet network that adapts to the protocol Hyper Text Transfer Protocol (HTTP. DASH technology allows a video in the video segmentation into several packages that will distreamingkan. DASH initial stage is to compress the video source to lower the bit rate video codec uses H.26. Video compressed further in the segmentation using MP4Box generates streaming packets with the specified duration. These packages are assembled into packets in a streaming media format Presentation Description (MPD or known as MPEG-DASH. Streaming video format MPEG-DASH run on a platform with the player bitdash teritegrasi bitcoin. With this scheme, the video will have several variants of the bit rates that gave rise to the concept of scalability of streaming video services on the client side. The main target of the mechanism is smooth the MPEG-DASH streaming video display on the client. The simulation results show that the scheme based scalable video streaming MPEG- DASH able to improve the quality of image display on the client side, where the procedure bufering videos can be made constant and fine for the duration of video views

  9. Scalable Video Streaming in Wireless Mesh Networks for Education

    Science.gov (United States)

    Liu, Yan; Wang, Xinheng; Zhao, Liqiang

    2011-01-01

    In this paper, a video streaming system for education based on a wireless mesh network is proposed. A wireless mesh network is a self-organizing, self-managing and reliable intelligent network, which allows educators to deploy a network quickly. Video streaming plays an important role in this system for multimedia data transmission. This new…

  10. Sub-Frame Crossing for Streaming Video over Wireless Networks

    OpenAIRE

    Aziz, Hussein Muzahim; Grahn, Håkan; Lundberg, Lars

    2010-01-01

    Transmitting a real time video streaming over a wireless network cannot guarantee that all the frames could be received by the mobile devices. The characteristics of a wireless network in terms of the available bandwidth, frame delay, and frame losses cannot be known in advanced. In this work, we propose a new mechanism for streaming video over a wireless channel. The proposed mechanism prevents freezing frames in the mobile devices. This is done by splitting the video frame in two sub-frames...

  11. Adaptive and ubiquitous video streaming over Wireless Mesh Networks

    Directory of Open Access Journals (Sweden)

    Malik Mubashir Hassan

    2016-10-01

    Full Text Available In recent years, with the dramatic improvement on scalability of H.264/MPEG-4 standard and growing demand for new multimedia services have spurred the research on scalable video streaming over wireless networks in both industry and academia. Video streaming applications are increasingly being deployed in Wireless Mesh Networks (WMNs. However, robust streaming of video over WMNs poses many challenges due to varying nature of wireless networks. Bit-errors, packet-losses and burst-packet-losses are very common in such type of networks, which severely influence the perceived video quality at receiving end. Therefore, a carefully-designed error recovery scheme must be employed. In this paper, we propose an interactive and ubiquitous video streaming scheme for Scalable Video Coding (SVC based video streaming over WMNs towards heterogeneous receivers. Intelligently taking the benefit of path diversity, the proposed scheme initially calculates the quality of all candidate paths and then based on quality of path it decides adaptively the size and level of error protection for all packets in order to combat the effect of losses on perceived quality of reconstructed video at receiving end. Our experimental results show that the proposed streaming approach can react to varying channel conditions with less degradation in video quality.

  12. Using DASH assisting network elements for optimizing video streaming quality

    NARCIS (Netherlands)

    J.W.M. Kleinrouweler (Jan Willem)

    2017-01-01

    textabstractOn-demand video streaming is a popular application which accounts for a large share of today's Internet traffic. Dynamic Adaptive Streaming over HTTP (DASH) is the major streaming technology used by large content providers. However, this technology suffers from performance problems when

  13. Quality of Experience Assessment of Video Quality in Social Clouds

    Directory of Open Access Journals (Sweden)

    Asif Ali Laghari

    2017-01-01

    Full Text Available Video sharing on social clouds is popular among the users around the world. High-Definition (HD videos have big file size so the storing in cloud storage and streaming of videos with high quality from cloud to the client are a big problem for service providers. Social clouds compress the videos to save storage and stream over slow networks to provide quality of service (QoS. Compression of video decreases the quality compared to original video and parameters are changed during the online play as well as after download. Degradation of video quality due to compression decreases the quality of experience (QoE level of end users. To assess the QoE of video compression, we conducted subjective (QoE experiments by uploading, sharing, and playing videos from social clouds. Three popular social clouds, Facebook, Tumblr, and Twitter, were selected to upload and play videos online for users. The QoE was recorded by using questionnaire given to users to provide their experience about the video quality they perceive. Results show that Facebook and Twitter compressed HD videos more as compared to other clouds. However, Facebook gives a better quality of compressed videos compared to Twitter. Therefore, users assigned low ratings for Twitter for online video quality compared to Tumblr that provided high-quality online play of videos with less compression.

  14. P2P Video Streaming Strategies based on Scalable Video Coding

    Directory of Open Access Journals (Sweden)

    F.A. López-Fuentes

    2015-02-01

    Full Text Available Video streaming over the Internet has gained significant popularity during the last years, and the academy and industry have realized a great research effort in this direction. In this scenario, scalable video coding (SVC has emerged as an important video standard to provide more functionality to video transmission and storage applications. This paper proposes and evaluates two strategies based on scalable video coding for P2P video streaming services. In the first strategy, SVC is used to offer differentiated quality video to peers with heterogeneous capacities. The second strategy uses SVC to reach a homogeneous video quality between different videos from different sources. The obtained results show that our proposed strategies enable a system to improve its performance and introduce benefits such as differentiated quality of video for clients with heterogeneous capacities and variable network conditions.

  15. Subjective quality assessment of an adaptive video streaming model

    Science.gov (United States)

    Tavakoli, Samira; Brunnström, Kjell; Wang, Kun; Andrén, Börje; Shahid, Muhammad; Garcia, Narciso

    2014-01-01

    With the recent increased popularity and high usage of HTTP Adaptive Streaming (HAS) techniques, various studies have been carried out in this area which generally focused on the technical enhancement of HAS technology and applications. However, a lack of common HAS standard led to multiple proprietary approaches which have been developed by major Internet companies. In the emerging MPEG-DASH standard the packagings of the video content and HTTP syntax have been standardized; but all the details of the adaptation behavior are left to the client implementation. Nevertheless, to design an adaptation algorithm which optimizes the viewing experience of the enduser, the multimedia service providers need to know about the Quality of Experience (QoE) of different adaptation schemes. Taking this into account, the objective of this experiment was to study the QoE of a HAS-based video broadcast model. The experiment has been carried out through a subjective study of the end user response to various possible clients' behavior for changing the video quality taking different QoE-influence factors into account. The experimental conclusions have made a good insight into the QoE of different adaptation schemes which can be exploited by HAS clients for designing the adaptation algorithms.

  16. Fast compressed domain motion detection in H.264 video streams for video surveillance applications

    DEFF Research Database (Denmark)

    Szczerba, Krzysztof; Forchhammer, Søren; Støttrup-Andersen, Jesper

    2009-01-01

    numbers of video streams on a single server. The focus of the work is on using the information in coded video streams to reduce the computational complexity and memory requirements, which translates into reduced hardware requirements and costs. The devised algorithm detects and segments activity based...

  17. The Use of Smart Glasses for Surgical Video Streaming.

    Science.gov (United States)

    Hiranaka, Takafumi; Nakanishi, Yuta; Fujishiro, Takaaki; Hida, Yuichi; Tsubosaka, Masanori; Shibata, Yosaku; Okimura, Kenjiro; Uemoto, Harunobu

    2017-04-01

    Observation of surgical procedures performed by experts is extremely important for acquisition and improvement of surgical skills. Smart glasses are small computers, which comprise a head-mounted monitor and video camera, and can be connected to the internet. They can be used for remote observation of surgeries by video streaming. Although Google Glass is the most commonly used smart glasses for medical purposes, it is still unavailable commercially and has some limitations. This article reports the use of a different type of smart glasses, InfoLinker, for surgical video streaming. InfoLinker has been commercially available in Japan for industrial purposes for more than 2 years. It is connected to a video server via wireless internet directly, and streaming video can be seen anywhere an internet connection is available. We have attempted live video streaming of knee arthroplasty operations that were viewed at several different locations, including foreign countries, on a common web browser. Although the quality of video images depended on the resolution and dynamic range of the video camera, speed of internet connection, and the wearer's attention to minimize image shaking, video streaming could be easily performed throughout the procedure. The wearer could confirm the quality of the video as the video was being shot by the head-mounted display. The time and cost for observation of surgical procedures can be reduced by InfoLinker, and further improvement of hardware as well as the wearer's video shooting technique is expected. We believe that this can be used in other medical settings.

  18. Can Viral Videos Help Beaver Restore Streams?

    Science.gov (United States)

    Castro, J. M.; Pollock, M. M.; Lewallen, G.; Jordan, C.; Woodruff, K.

    2015-12-01

    Have you watched YouTube lately? Did you notice the plethora of cute animal videos? Researchers, including members of our Beaver Restoration Research team, have been studying the restoration potential of beaver for decades, yet in the past few years, beaver have gained broad acclaim and some much deserved credit for restoration of aquatic systems in North America. Is it because people can now see these charismatic critters in action from the comfort of their laptops? While the newly released Beaver Restoration Guidebook attempts to answer many questions, sadly, this is not one of them. We do, however, address the use of beaver (Castor canadensis) in stream, wetland, and floodplain restoration and discuss the many positive effects of beaver on fluvial ecosystems. Our team, composed of researchers from NOAA National Marine Fisheries Service, US Fish and Wildlife Service, US Forest Service, and Portland State University, has developed a scientifically rigorous, yet accessible, practitioner's guide that provides a synthesis of the best available science for using beaver to improve ecosystem functions. Divided into two broad sections -- Beaver Ecology and Beaver Restoration and Management -- the guidebook focuses on the many ways in which beaver improve habitat, primarily through the construction of dams that impound water and retain sediment. In Beaver Ecology, we open with a discussion of the general effects that beaver dams have on physical and biological processes, and we close with "Frequently Asked Questions" and "Myth Busters". In Restoration and Management, we discuss common emerging restoration techniques and methods for mitigating unwanted beaver effects, followed by case studies from pioneering practitioners who have used many of these beaver restoration techniques in the field. The lessons they have learned will help guide future restoration efforts. We have also included a comprehensive beaver ecology library of over 1400 references from scientific journals

  19. Effective Quality-of-Service Renegotiating Schemes for Streaming Video

    Directory of Open Access Journals (Sweden)

    Song Hwangjun

    2004-01-01

    Full Text Available This paper presents effective quality-of-service renegotiating schemes for streaming video. The conventional network supporting quality of service generally allows a negotiation at a call setup. However, it is not efficient for the video application since the compressed video traffic is statistically nonstationary. Thus, we consider the network supporting quality-of-service renegotiations during the data transmission and study effective quality-of-service renegotiating schemes for streaming video. The token bucket model, whose parameters are token filling rate and token bucket size, is adopted for the video traffic model. The renegotiating time instants and the parameters are determined by analyzing the statistical information of compressed video traffic. In this paper, two renegotiating approaches, that is, fixed renegotiating interval case and variable renegotiating interval case, are examined. Finally, the experimental results are provided to show the performance of the proposed schemes.

  20. Receiver buffer requirement for video streaming over TCP

    Science.gov (United States)

    Kim, Taehyun; Ammar, Mostafa H.

    2006-01-01

    TCP is one of the most widely used transport protocols for video streaming. However, the rate variability of TCP makes it difficult to provide good video quality. To accommodate the variability, video streaming applications require receiver-side buffering. In current practice, however, there are no systematic guidelines for the provisioning of the receiver buffer, and smooth playout is insured through over-provisioning. In this work, we are interested in memory-constrained applications where it is important to determine the right size of receiver buffer in order to insure a prescribed video quality. To that end, we characterize video streaming over TCP in a systematic and quantitative manner. We first model a video streaming system analytically and derive an expression of receiver buffer requirement based on the model. Our analysis shows that the receiver buffer requirement is determined by the network characteristics and desired video quality. Experimental results validate our model and demonstrate that the receiver buffer requirement achieves desired video quality.

  1. Factors that Influence Learning Satisfaction Delivered by Video Streaming Technology

    Science.gov (United States)

    Keenan, Daniel Stephen

    2010-01-01

    In 2005, over 100,000 e-Learning courses were offered in over half of all U.S. postsecondary education institutions with nearly 90% of all community colleges and four year institutions offering online education. Streaming video is commonplace across the internet offering seamless video and sound anywhere connectivity is available effectively…

  2. Layer-Optimized Streaming of Motion-Compensated Orthogonal Video

    OpenAIRE

    SHEN, Wenjie

    2013-01-01

    This report presents a layer-optimized streaming technique for delivering video content over the Internet using quality-scalable motion-compensated orthogonal video. We use Motion-Compensated Orthogonal Transforms (MCOT) to remove temporal and spatial redundancy. The resulting subbands are quantized and entropy coded by Embedded Block Coding with Optimized Truncations (EBCOT). Therefore, we are able to encode the input video into multiple quality layers with sequential decoding dependency. A ...

  3. Sink or Swim: Taking Advantage of Developments in Video Streaming

    Science.gov (United States)

    Fill, Karen; Ottewill, Roger

    2006-01-01

    Amongst the many recent developments in learning technology, video streaming appears to offer a considerable range of benefits for tutors and learners alike. For these to be fully realised, however, various conditions have to be met. Merely making streams available and directing students to them, does not necessarily result in quality, or indeed…

  4. A Pre-Scheduling Mechanism in LTE Handover for Streaming Video

    Directory of Open Access Journals (Sweden)

    Wei-Kuang Lai

    2016-03-01

    Full Text Available This paper focuses on downlink packet scheduling for streaming video in Long Term Evolution (LTE. As a hard handover is adopted in LTE and has the period of breaking connection, it may cause a low user-perceived video quality. Therefore, we propose a handover prediction mechanism and a pre-scheduling mechanism to dynamically adjust the data rates of transmissions for providing a high quality of service (QoS for streaming video before new connection establishment. Advantages of our method in comparison to the exponential/proportional fair (EXP/PF scheme are shown through simulation experiments.

  5. A BitTorrent-Based Dynamic Bandwidth Adaptation Algorithm for Video Streaming

    Science.gov (United States)

    Hsu, Tz-Heng; Liang, You-Sheng; Chiang, Meng-Shu

    In this paper, we propose a BitTorrent-based dynamic bandwidth adaptation algorithm for video streaming. Two mechanisms to improve the original BitTorrent protocol are proposed: (1) the decoding order frame first (DOFF) frame selection algorithm and (2) the rarest I frame first (RIFF) frame selection algorithm. With the proposed algorithms, a peer can periodically check the number of downloaded frames in the buffer and then allocate the available bandwidth adaptively for video streaming. As a result, users can have smooth video playout experience with the proposed algorithms.

  6. Real-time video streaming in mobile cloud over heterogeneous wireless networks

    Science.gov (United States)

    Abdallah-Saleh, Saleh; Wang, Qi; Grecos, Christos

    2012-06-01

    Recently, the concept of Mobile Cloud Computing (MCC) has been proposed to offload the resource requirements in computational capabilities, storage and security from mobile devices into the cloud. Internet video applications such as real-time streaming are expected to be ubiquitously deployed and supported over the cloud for mobile users, who typically encounter a range of wireless networks of diverse radio access technologies during their roaming. However, real-time video streaming for mobile cloud users across heterogeneous wireless networks presents multiple challenges. The network-layer quality of service (QoS) provision to support high-quality mobile video delivery in this demanding scenario remains an open research question, and this in turn affects the application-level visual quality and impedes mobile users' perceived quality of experience (QoE). In this paper, we devise a framework to support real-time video streaming in this new mobile video networking paradigm and evaluate the performance of the proposed framework empirically through a lab-based yet realistic testing platform. One particular issue we focus on is the effect of users' mobility on the QoS of video streaming over the cloud. We design and implement a hybrid platform comprising of a test-bed and an emulator, on which our concept of mobile cloud computing, video streaming and heterogeneous wireless networks are implemented and integrated to allow the testing of our framework. As representative heterogeneous wireless networks, the popular WLAN (Wi-Fi) and MAN (WiMAX) networks are incorporated in order to evaluate effects of handovers between these different radio access technologies. The H.264/AVC (Advanced Video Coding) standard is employed for real-time video streaming from a server to mobile users (client nodes) in the networks. Mobility support is introduced to enable continuous streaming experience for a mobile user across the heterogeneous wireless network. Real-time video stream packets

  7. Video streaming in nursing education: bringing life to online education.

    Science.gov (United States)

    Smith-Stoner, Marilyn; Willer, Ann

    2003-01-01

    Distance education is a standard form of instruction for many colleges of nursing. Web-based course and program content has been delivered primarily through text-based presentations such as PowerPoint slides and Web search activities. However, the rapid pace of technological innovation is making available more sophisticated forms of delivery such as video streaming. High-quality video streams, created at the instructor's desktop or in basic recording studios, can be produced that build on PowerPoint or create new media for use on the Web. The technology required to design, produce, and upload short video-streamed course content objects to the Internet is described. The preparation of materials, suggested production guidelines, and examples of information presented via desktop video methods are presented.

  8. Interactive streaming of stored multiview video using redundant frame structures.

    Science.gov (United States)

    Cheung, Gene; Ortega, Antonio; Cheung, Ngai-Man

    2011-03-01

    While much of multiview video coding focuses on the rate-distortion performance of compressing all frames of all views for storage or non-interactive video delivery over networks, we address the problem of designing a frame structure to enable interactive multiview streaming, where clients can interactively switch views during video playback. Thus, as a client is playing back successive frames (in time) for a given view, it can send a request to the server to switch to a different view while continuing uninterrupted temporal playback. Noting that standard tools for random access (i.e., I-frame insertion) can be bandwidth-inefficient for this application, we propose a redundant representation of I-, P-, and "merge" frames, where each original picture can be encoded into multiple versions, appropriately trading off expected transmission rate with storage, to facilitate view switching. We first present ad hoc frame structures with good performance when the view-switching probabilities are either very large or very small. We then present optimization algorithms that generate more general frame structures with better overall performance for the general case. We show in our experiments that we can generate redundant frame structures offering a range of tradeoff points between transmission and storage, e.g., outperforming simple I-frame insertion structures by up to 45% in terms of bandwidth efficiency at twice the storage cost.

  9. Subjective evaluation of H.265/HEVC based dynamic adaptive video streaming over HTTP (HEVC-DASH)

    Science.gov (United States)

    Irondi, Iheanyi; Wang, Qi; Grecos, Christos

    2015-02-01

    The Dynamic Adaptive Streaming over HTTP (DASH) standard is becoming increasingly popular for real-time adaptive HTTP streaming of internet video in response to unstable network conditions. Integration of DASH streaming techniques with the new H.265/HEVC video coding standard is a promising area of research. The performance of HEVC-DASH systems has been previously evaluated by a few researchers using objective metrics, however subjective evaluation would provide a better measure of the user's Quality of Experience (QoE) and overall performance of the system. This paper presents a subjective evaluation of an HEVC-DASH system implemented in a hardware testbed. Previous studies in this area have focused on using the current H.264/AVC (Advanced Video Coding) or H.264/SVC (Scalable Video Coding) codecs and moreover, there has been no established standard test procedure for the subjective evaluation of DASH adaptive streaming. In this paper, we define a test plan for HEVC-DASH with a carefully justified data set employing longer video sequences that would be sufficient to demonstrate the bitrate switching operations in response to various network condition patterns. We evaluate the end user's real-time QoE online by investigating the perceived impact of delay, different packet loss rates, fluctuating bandwidth, and the perceived quality of using different DASH video stream segment sizes on a video streaming session using different video sequences. The Mean Opinion Score (MOS) results give an insight into the performance of the system and expectation of the users. The results from this study show the impact of different network impairments and different video segments on users' QoE and further analysis and study may help in optimizing system performance.

  10. Distortion Optimized Packet Scheduling and Prioritization of Multiple Video Streams over 802.11e Networks

    Directory of Open Access Journals (Sweden)

    Ilias Politis

    2007-01-01

    Full Text Available This paper presents a generic framework solution for minimizing video distortion of all multiple video streams transmitted over 802.11e wireless networks, including intelligent packet scheduling and channel access differentiation mechanisms. A distortion prediction model designed to capture the multireferenced frame coding characteristic of H.264/AVC encoded videos is used to predetermine the distortion importance of each video packet in all streams. Two intelligent scheduling algorithms are proposed: the “even-loss distribution,” where each video sender is experiencing the same loss and the “greedy-loss distribution” packet scheduling, where selected packets are dropped over all streams, ensuring that the most significant video stream in terms of picture context and quality characteristics will experience minimum losses. The proposed model has been verified with actual distortion measurements and has been found more accurate than the “additive distortion” model that omits the correlation among lost frames. The paper includes analytical and simulation results from the comparison of both schemes and from their comparison to the simplified additive model, for different video sequences and channel conditions.

  11. Scalable Video Streaming Relay for Smart Mobile Devices in Wireless Networks.

    Science.gov (United States)

    Kwon, Dongwoo; Je, Huigwang; Kim, Hyeonwoo; Ju, Hongtaek; An, Donghyeok

    2016-01-01

    Recently, smart mobile devices and wireless communication technologies such as WiFi, third generation (3G), and long-term evolution (LTE) have been rapidly deployed. Many smart mobile device users can access the Internet wirelessly, which has increased mobile traffic. In 2014, more than half of the mobile traffic around the world was devoted to satisfying the increased demand for the video streaming. In this paper, we propose a scalable video streaming relay scheme. Because many collisions degrade the scalability of video streaming, we first separate networks to prevent excessive contention between devices. In addition, the member device controls the video download rate in order to adapt to video playback. If the data are sufficiently buffered, the member device stops the download. If not, it requests additional video data. We implemented apps to evaluate the proposed scheme and conducted experiments with smart mobile devices. The results showed that our scheme improves the scalability of video streaming in a wireless local area network (WLAN).

  12. Medical Students' Perceptions of Video-Linked Lectures and Video-Streaming

    Science.gov (United States)

    Wang, RuoLan; Mattick, Karen; Dunne, Elisabeth

    2010-01-01

    Video-linked lectures allow healthcare students across multiple sites, and between university and hospital bases, to come together for the purposes of shared teaching. Recording and streaming video-linked lectures allows students to view them at a later date and provides an additional resource to support student learning. As part of a UK Higher…

  13. For Video Streaming/Delivery: Is HTML5 the Real Fix?

    Directory of Open Access Journals (Sweden)

    John Millard

    2013-10-01

    Full Text Available The general movement towards streaming or playing videos on the web has grown exponentially in the last decade. The combination of new streaming technologies and faster Internet connections continue to provide enhanced and robust user experience for video content. For many organizations, adding videos on their websites has transitioned from a “cool” feature to a mission critical service. Some of the benefits in putting videos online include: to engage and convert visitors, to raise awareness or drive interest, to share inspirational stories or recent unique events, etc. Along with the growth in the use and need for video content on the web; delivering videos online also remains a messy activity for developers and web teams. Examples of existing challenges include creating more accessible videos with captions and delivering content (using adaptive streaming for the diverse range of mobile and tablet devices. In this article, we report on the decision-making and early results in using the Kaltura video platform in two popular library platforms: CONTENTdm and DSpace.

  14. Using Learning Styles and Viewing Styles in Streaming Video

    Science.gov (United States)

    de Boer, Jelle; Kommers, Piet A. M.; de Brock, Bert

    2011-01-01

    Improving the effectiveness of learning when students observe video lectures becomes urgent with the rising advent of (web-based) video materials. Vital questions are how students differ in their learning preferences and what patterns in viewing video can be detected in log files. Our experiments inventory students' viewing patterns while watching…

  15. Using learning styles and viewing styles in streaming video

    NARCIS (Netherlands)

    de Boer, Jelle; Kommers, Petrus A.M.; de Brock, Bert

    2011-01-01

    Improving the effectiveness of learning when students observe video lectures becomes urgent with the rising advent of (web-based) video materials. Vital questions are how students differ in their learning preferences and what patterns in viewing video can be detected in log files. Our experiments

  16. Using learning styles and viewing styles in streaming video

    NARCIS (Netherlands)

    de Boer, Jelle; Kommers, Piet A. M.; de Brock, Bert

    Improving the effectiveness of learning when students observe video lectures becomes urgent with the rising advent of (web-based) video materials. Vital questions are how students differ in their learning preferences and what patterns in viewing video can be detected in log files. Our experiments

  17. Case study: student perceptions of video streaming nursing class sessions.

    Science.gov (United States)

    Wall Parilo, Denise M; Parsh, Bridget

    2014-03-01

    Due to space constraints, students in their pediatric and obstetrical nursing courses received lecture in two formats: live lecture and video-streamed lecture. Live lecture is the traditional classroom format of live, in-person lecture without recording archives, whereas video streaming is live (synchronous) online lecture, also recorded for digital archive (asynchronous viewing). At the end of the semester, students (N = 53) responded to a survey about what they liked about both methods of instruction. Results reveal strengths of both methods and suggest ways to make both methods more effective. Copyright 2014, SLACK Incorporated.

  18. Study of Repair Protocols for Live Video Streaming Distributed Systems

    OpenAIRE

    Giroire, Frédéric; Huin, Nicolas

    2015-01-01

    International audience; —We study distributed systems for live video streaming. These systems can be of two types: structured and un-structured. In an unstructured system, the diffusion is done opportunistically. The advantage is that it handles churn, that is the arrival and departure of users, which is very high in live streaming systems, in a smooth way. On the opposite, in a structured system, the diffusion of the video is done using explicit diffusion trees. The advantage is that the dif...

  19. Online and unsupervised face recognition for continuous video stream

    Science.gov (United States)

    Huo, Hongwen; Feng, Jufu

    2009-10-01

    We present a novel online face recognition approach for video stream in this paper. Our method includes two stages: pre-training and online training. In the pre-training phase, our method observes interactions, collects batches of input data, and attempts to estimate their distributions (Box-Cox transformation is adopted here to normalize rough estimates). In the online training phase, our method incrementally improves classifiers' knowledge of the face space and updates it continuously with incremental eigenspace analysis. The performance achieved by our method shows its great potential in video stream processing.

  20. A Video Streaming Application Using Mobile Media Application Programming Interface

    OpenAIRE

    Henning Titi Ciptaningtyas; Henry Pratama,; Ary Mazharuddin Shiddiqi

    2010-01-01

    Recently, the development of mobile phone technology is growing rapidly. These developments led to the emerging of a multimedia mobile phone that supports Wireless Local Area Network (WLAN). However, the use of WLAN technology on mobile phones to access the streaming video is very rarely encountered. While the current S60 Symbian operating system as a multimedia mobile phone is very reliable in handling a variety of media such as video.The discussion in this study presents the making of a vid...

  1. EZBC video streaming with channel coding and error concealment

    Science.gov (United States)

    Bajic, Ivan V.; Woods, John W.

    2003-06-01

    In this text we present a system for streaming video content encoded using the motion-compensated Embedded Zero Block Coder (EZBC). The system incorporates unequal loss protection in the form of multiple description FEC (MD-FEC) coding, which provides adequate protection for the embedded video bitstream when the loss process is not very bursty. The adverse effects of burst losses are reduced using a novel motion-compensated error concealmet method.

  2. Video Streaming for Creative Writing at International Elementary School

    Directory of Open Access Journals (Sweden)

    Deni Darmawan

    2013-02-01

    Full Text Available This study aims at overcoming difficulty in learning language, both in Indonesian Language and English at international elementary school, especially in creative writing. Creative writing as part of human activity is creativity with language medium as prose (narrative, description, poem (old, new and modern, as well as drama (dialogue, role play, and sosio drama. Specific target to be achieved is the design of Video Streaming for all kinds of creative writing in the language of Indonesian and English. This investigation is a continuation of the previos investigation that has managed to make a video leaning in English for Math and Science as integrated learning to early class at international elementary school. The method used follow the principles of developmental reasearch. The firts stage is script writing video streaming through brainstorming with teachers, lecturers, teams of investigators Indonesia (UPI and Malaysia (USM. The second stage manuscript, making finalization Video Streaming, make the Web, media experts and creative writing material team investigators. The third stage, testing the Video Streaming, Web and dissemination of results into all the international elementary school in Indonesia and Malaysia.

  3. Error and Congestion Resilient Video Streaming over Broadband Wireless

    Directory of Open Access Journals (Sweden)

    Laith Al-Jobouri

    2015-04-01

    Full Text Available In this paper, error resilience is achieved by adaptive, application-layer rateless channel coding, which is used to protect H.264/Advanced Video Coding (AVC codec data-partitioned videos. A packetization strategy is an effective tool to control error rates and, in the paper, source-coded data partitioning serves to allocate smaller packets to more important compressed video data. The scheme for doing this is applied to real-time streaming across a broadband wireless link. The advantages of rateless code rate adaptivity are then demonstrated in the paper. Because the data partitions of a video slice are each assigned to different network packets, in congestion-prone wireless networks the increased number of packets per slice and their size disparity may increase the packet loss rate from buffer overflows. As a form of congestion resilience, this paper recommends packet-size dependent scheduling as a relatively simple way of alleviating the buffer-overflow problem arising from data-partitioned packets. The paper also contributes an analysis of data partitioning and packet sizes as a prelude to considering scheduling regimes. The combination of adaptive channel coding and prioritized packetization for error resilience with packet-size dependent packet scheduling results in a robust streaming scheme specialized for broadband wireless and real-time streaming applications such as video conferencing, video telephony, and telemedicine.

  4. Optimized H.264/AVC-Based Bit Stream Switching for Mobile Video Streaming

    Directory of Open Access Journals (Sweden)

    Liebl Günther

    2006-01-01

    Full Text Available We show the suitability of H.264/MPEG-4 AVC extended profile for wireless video streaming applications. In particular, we exploit the advanced bit stream switching capabilities using SP/SI pictures defined in the H.264/MPEG-4 AVC standard. For both types of switching pictures, optimized encoders are developed. We introduce a framework for dynamic switching and frame scheduling. For this purpose we define an appropriate abstract representation for media encoded for video streaming, as well as for the characteristics of wireless variable bit rate channels. The achievable performance gains over H.264/MPEG-4 AVC with constant bit rate (CBR encoding are shown for wireless video streaming over enhanced GPRS (EGPRS.

  5. Adaptive Error Resilience for Video Streaming

    Directory of Open Access Journals (Sweden)

    Lakshmi R. Siruvuri

    2009-01-01

    Full Text Available Compressed video sequences are vulnerable to channel errors, to the extent that minor errors and/or small losses can result in substantial degradation. Thus, protecting compressed data against channel errors is imperative. The use of channel coding schemes can be effective in reducing the impact of channel errors, although this requires that extra parity bits to be transmitted, thus utilizing more bandwidth. However, this can be ameliorated if the transmitter can tailor the parity data rate based on its knowledge regarding current channel conditions. This can be achieved via feedback from the receiver to the transmitter. This paper describes a channel emulation system comprised of a server/proxy/client combination that utilizes feedback from the client to adapt the number of Reed-Solomon parity symbols used to protect compressed video sequences against channel errors.

  6. Social Backup and Sharing of Video using HTTP Adaptive Streaming

    NARCIS (Netherlands)

    Stokking, H.M.; Klos, V.B.; Jiang, J.; Casetti, C.

    2013-01-01

    This paper is on social backup, sharing and remote access of video using HTTP Adaptive Streaming. A social backup is a backup at the location, and thus on the equipment, of (close) friends and family. Backups are created at friends’ locations, matching the hosting user’s interest with the content

  7. Struggles and Solutions for Streaming Video in the Online Classroom

    Science.gov (United States)

    Fruin, Christine

    2012-01-01

    The upcoming round of exemptions to the Digital Millennium Copyright Act of 1998 anticircumvention provision and the questions raised by the copyright infringement lawsuit filed against the against University of California, Los Angeles (UCLA) for its streaming video practices illustrate the problematic state of the law concerning the digitization…

  8. Modeling the time--varying subjective quality of HTTP video streams with rate adaptations.

    Science.gov (United States)

    Chen, Chao; Choi, Lark Kwon; de Veciana, Gustavo; Caramanis, Constantine; Heath, Robert W; Bovik, Alan C

    2014-05-01

    Newly developed hypertext transfer protocol (HTTP)-based video streaming technologies enable flexible rate-adaptation under varying channel conditions. Accurately predicting the users' quality of experience (QoE) for rate-adaptive HTTP video streams is thus critical to achieve efficiency. An important aspect of understanding and modeling QoE is predicting the up-to-the-moment subjective quality of a video as it is played, which is difficult due to hysteresis effects and nonlinearities in human behavioral responses. This paper presents a Hammerstein-Wiener model for predicting the time-varying subjective quality (TVSQ) of rate-adaptive videos. To collect data for model parameterization and validation, a database of longer duration videos with time-varying distortions was built and the TVSQs of the videos were measured in a large-scale subjective study. The proposed method is able to reliably predict the TVSQ of rate adaptive videos. Since the Hammerstein-Wiener model has a very simple structure, the proposed method is suitable for online TVSQ prediction in HTTP-based streaming.

  9. Scalable and Media Aware Adaptive Video Streaming over Wireless Networks

    Science.gov (United States)

    Tizon, Nicolas; Pesquet-Popescu, Béatrice

    2008-12-01

    This paper proposes an advanced video streaming system based on scalable video coding in order to optimize resource utilization in wireless networks with retransmission mechanisms at radio protocol level. The key component of this system is a packet scheduling algorithm which operates on the different substreams of a main scalable video stream and which is implemented in a so-called media aware network element. The concerned type of transport channel is a dedicated channel subject to parameters (bitrate, loss rate) variations on the long run. Moreover, we propose a combined scalability approach in which common temporal and SNR scalability features can be used jointly with a partitioning of the image into regions of interest. Simulation results show that our approach provides substantial quality gain compared to classical packet transmission methods and they demonstrate how ROI coding combined with SNR scalability allows to improve again the visual quality.

  10. Constructing a Streaming Video-Based Learning Forum for Collaborative Learning

    Science.gov (United States)

    Chang, Chih-Kai

    2004-01-01

    As web-based courses using videos have become popular in recent years, the issue of managing audio-visual aids has become pertinent. Generally, the contents of audio-visual aids may include a lecture, an interview, a report, or an experiment, which may be transformed into a streaming format capable of making the quality of Internet-based videos…

  11. A Modified Multiview Video Streaming System Using 3-Tier Architecture

    Directory of Open Access Journals (Sweden)

    Mohamed M. Fouad

    2016-01-01

    Full Text Available In this paper, we present a modified inter-view prediction Multiview Video Coding (MVC scheme from the perspective of viewer's interactivity. When a viewer requests some view(s, our scheme leads to lower transmission bit-rate. We develop an interactive multiview video streaming system exploiting that modified MVC scheme. Conventional interactive multiview video systems require high bandwidth due to redundant data being transferred. With real data test sequences, clear improvements are shown using the proposed interactive multiview video system compared to competing ones in terms of the average transmission bit-rate and storage size of the decoded (i.e., transferred data with comparable rate-distortion.

  12. A time-varying subjective quality model for mobile streaming videos with stalling events

    Science.gov (United States)

    Ghadiyaram, Deepti; Pan, Janice; Bovik, Alan C.

    2015-09-01

    Over-the-top mobile video streaming is invariably influenced by volatile network conditions which cause playback interruptions (stalling events), thereby impairing users' quality of experience (QoE). Developing models that can accurately predict users' QoE could enable the more efficient design of quality-control protocols for video streaming networks that reduce network operational costs while still delivering high-quality video content to the customers. Existing objective models that predict QoE are based on global video features, such as the number of stall events and their lengths, and are trained and validated on a small pool of ad hoc video datasets, most of which are not publicly available. The model we propose in this work goes beyond previous models as it also accounts for the fundamental effect that a viewer's recent level of satisfaction or dissatisfaction has on their overall viewing experience. In other words, the proposed model accounts for and adapts to the recency, or hysteresis effect caused by a stall event in addition to accounting for the lengths, frequency of occurrence, and the positions of stall events - factors that interact in a complex way to affect a user's QoE. On the recently introduced LIVE-Avvasi Mobile Video Database, which consists of 180 distorted videos of varied content that are afflicted solely with over 25 unique realistic stalling events, we trained and validated our model to accurately predict the QoE, attaining standout QoE prediction performance.

  13. Streaming Video Games: Copyright Infringement or Protected Speech?

    Directory of Open Access Journals (Sweden)

    Eirik Evert Elias Jungar

    2016-12-01

    Full Text Available Streaming video games, that is, live broadcasting playing video games on the internet, is incredibly popular. Millions tune into twitch.tv daily to watch eSport tournaments, their favourite streamer, and chat with other viewers. But all is not rosy in the world of streaming games. Recently, some game developers have aggressively exercised their copyright to, firstly, claim part of the streamers’ revenue, and secondly, control the context in which their game is shown. The article analyzes whether game developers have, and should have, such rights under EU copyright law. Reaching the conclusion that video game streams infringe the game developer’s right to communicate their works to the public, I argue that freedom of expression can and should be used to rein in their rights in certain cases. Subjecting the lawfulness of streams to game developers’ good will risks stifling the expressions of streamers. The streamers, their audience, and even the copyright holders, would be worse off for it.

  14. Optimal Multi-Interface Selection for Mobile Video Streaming in Efficient Battery Consumption and Data Usage

    Directory of Open Access Journals (Sweden)

    Seonghoon Moon

    2016-01-01

    Full Text Available With the proliferation of high-performance, large-screen mobile devices, users’ expectations of having access to high-resolution video content in smooth network environments are steadily growing. To guarantee such stable streaming, a high cellular network bandwidth is required; yet network providers often charge high prices for even limited data plans. Moreover, the costs of smoothly streaming high-resolution videos are not merely monetary; the device’s battery life must also be accounted for. To resolve these problems, we design an optimal multi-interface selection system for streaming video over HTTP/TCP. An optimization problem including battery life and LTE data constraints is derived and then solved using binary integer programming. Additionally, the system is designed with an adoption of split-layer scalable video coding, which provides direct adaptations of video quality and prevents out-of-order packet delivery problems. The proposed system is evaluated using a prototype application in a real, iOS-based device as well as through experiments conducted in heterogeneous mobile scenarios. Results show that the system not only guarantees the highest-possible video quality, but also prevents reckless consumption of LTE data and battery life.

  15. Uncoordinated Multi-user Video Streaming in VANETs using Skype

    DEFF Research Database (Denmark)

    Belyaev, Evgeny; Moreschini, Sergio; Vinel, Alexey

    2017-01-01

    Real-time video delivery in Vehicle-to-Infrastructure (V2I) scenario enables a variety of multimedia vehicular services. We conduct experiments with Dedicated Short Range Communications (DSRC) transceivers located in the mutual proximity and exchanging Skype video calls traffic. We demonstrate...

  16. A Stream Runs through IT: Using Streaming Video to Teach Information Technology

    Science.gov (United States)

    Nicholson, Jennifer; Nicholson, Darren B.

    2010-01-01

    Purpose: The purpose of this paper is to report student and faculty perceptions from an introductory management information systems course that uses multimedia, specifically streaming video, as a vehicle for teaching students skills in Microsoft Excel and Access. Design/methodology/approach: Student perceptions are captured via a qualitative…

  17. SVC VIDEO STREAM ALLOCATION AND ADAPTATION IN HETEROGENEOUS NETWORK

    Directory of Open Access Journals (Sweden)

    E. A. Pakulova

    2016-07-01

    Full Text Available The paper deals with video data transmission in format H.264/SVC standard with QoS requirements satisfaction. The Sender-Side Path Scheduling (SSPS algorithm and Sender-Side Video Adaptation (SSVA algorithm were developed. SSPS algorithm gives the possibility to allocate video traffic among several interfaces while SSVA algorithm dynamically changes the quality of video sequence in relation to QoS requirements. It was shown that common usage of two developed algorithms enables to aggregate throughput of access networks, increase parameters of Quality of Experience and decrease losses in comparison with Round Robin algorithm. For evaluation of proposed solution, the set-up was made. The trace files with throughput of existing public networks were used in experiments. Based on this information the throughputs of networks were limited and losses for paths were set. The results of research may be used for study and transmission of video data in heterogeneous wireless networks.

  18. Simultaneous Class-based and Live Video Streamed Teaching

    DEFF Research Database (Denmark)

    Ørngreen, Rikke; Levinsen, Karin Ellen Tweddell; Jelsbak, Vibe Alopaeus

    2015-01-01

    The Bachelor Programme in Biomedical Laboratory Analysis at VIA's healthcare university college in Aarhus has established a blended class which combines traditional and live broadcast teaching (via an innovative choice of video conferencing system). On the so-called net-days, students have....... From here a number of general principles and perspective were derived for the specific program which can be useful to contemplate in general for similar educations. It is concluded that the blended class model using live video stream represents a viable pedagogical solution for the Bachelor Programme...... sheds light on the pedagogical challenges, the educational designs possible, the opportunities and constrains associated with video conferencing as a pedagogical practice, as well as the technological, structural and organisational conditions involved. In this paper a participatory action research...

  19. Emergency department orientation utilizing web-based streaming video.

    Science.gov (United States)

    Mahadevan, Swaminatha V; Gisondi, Michael A; Sovndal, Shannon S; Gilbert, Gregory H

    2004-08-01

    To assure a smooth transition to their new work environment, rotating students and housestaff require detailed orientations to the physical layout and operations of the emergency department. Although such orientations are useful for new staff members, they represent a significant time commitment for the faculty members charged with this task. To address this issue, the authors developed a series of short instructional videos that provide a comprehensive and consistent method of emergency department orientation. The videos are viewed through Web-based streaming technology that allows learners to complete the orientation process from any computer with Internet access before their first shift. This report describes the stepwise process used to produce these videos and discusses the potential benefits of converting to an Internet-based orientation system.

  20. In-Network Adaptation of Video Streams Using Network Processors

    Directory of Open Access Journals (Sweden)

    Mohammad Shorfuzzaman

    2009-01-01

    problem can be addressed, near the network edge, by applying dynamic, in-network adaptation (e.g., transcoding of video streams to meet available connection bandwidth, machine characteristics, and client preferences. In this paper, we extrapolate from earlier work of Shorfuzzaman et al. 2006 in which we implemented and assessed an MPEG-1 transcoding system on the Intel IXP1200 network processor to consider the feasibility of in-network transcoding for other video formats and network processor architectures. The use of “on-the-fly” video adaptation near the edge of the network offers the promise of simpler support for a wide range of end devices with different display, and so forth, characteristics that can be used in different types of environments.

  1. Video Streaming Transfer in a Smart Satellite Mobile Environment

    Directory of Open Access Journals (Sweden)

    Nedo Celandroni

    2009-01-01

    satellite link for transmitting video streams to a bus, where they are relayed to passengers' devices. We say that a bus works in smart mode if it takes advantage of the knowledge of the exact points where fixed obstacles will prevent receiving the satellite signal for a certain time period. This information is sent to the hub via a return channel. The hub, in its turn, suspends the transmissions to that specific bus for the given time interval, thus avoiding information losses and unnecessary bandwidth occupation. Buffering video packets, without any quality of service (QoS degradation, seamlessly compensates channel blockages up to a given duration. We determine the most appropriate transmission parameters for video streaming with good video QoS in a mobile satellite environment; moreover, we evaluate how “smart” the system can be in terms of bandwidth saving, by comparing it with the situation where the bus does not exploit the description of its route, still maintaining the same QoS requirements.

  2. Application-adapted mobile 3D video coding and streaming — A survey

    Science.gov (United States)

    Liu, Yanwei; Ci, Song; Tang, Hui; Ye, Yun

    2012-03-01

    3D video technologies have been gradually matured to be moved into mobile platforms. In the mobile environments, the specific characteristics of wireless network and mobile device present great challenges for 3D video coding and streaming. The application-adapted mobile 3D video coding and streaming technologies are urgently needed. Based on the mobile 3D video application framework, this paper reviews the state-of-the-art technologies of mobile 3D video coding and streaming. Specifically, the mobile 3D video formats and the corresponding coding methods are firstly reviewed and then the streaming adaptation technologies including 3D video transcoding, 3D video rate control and cross-layer optimized 3D video streaming are surveyed. [Figure not available: see fulltext.

  3. Towards User Experience-Driven Adaptive Uplink Video Transmission for Automotive Applications

    OpenAIRE

    Lottermann, Christian

    2016-01-01

    The focus of this thesis is to enable user experience-driven uplink video streaming from mobile video sources with limited computational capacity and to apply these to resource-constraint automotive environments. The first part investigates perceptual quality-aware encoding of videos, the second part proposes camera context-based estimators of temporal and spatial activities for videos captured by a front-facing camera of a vehicle, and the last part studies the upstreaming of videos from a m...

  4. A real-time remote video streaming platform for ultrasound imaging.

    Science.gov (United States)

    Ahmadi, Mehdi; Gross, Warren J; Kadoury, Samuel

    2016-08-01

    Ultrasound is a viable imaging technology in remote and resources-limited areas. Ultrasonography is a user-dependent skill which depends on a high degree of training and hands-on experience. However, there is a limited number of skillful sonographers located in remote areas. In this work, we aim to develop a real-time video streaming platform which allows specialist physicians to remotely monitor ultrasound exams. To this end, an ultrasound stream is captured and transmitted through a wireless network into remote computers, smart-phones and tablets. In addition, the system is equipped with a camera to track the position of the ultrasound probe. The main advantage of our work is using an open source platform for video streaming which gives us more control over streaming parameters than the available commercial products. The transmission delays of the system are evaluated for several ultrasound video resolutions and the results show that ultrasound videos close to the high-definition (HD) resolution can be received and displayed on an Android tablet with the delay of 0.5 seconds which is acceptable for accurate real-time diagnosis.

  5. Learning a Continuous-Time Streaming Video QoE Model.

    Science.gov (United States)

    Ghadiyaram, Deepti; Pan, Janice; Bovik, Alan C

    2018-05-01

    Over-the-top adaptive video streaming services are frequently impacted by fluctuating network conditions that can lead to rebuffering events (stalling events) and sudden bitrate changes. These events visually impact video consumers' quality of experience (QoE) and can lead to consumer churn. The development of models that can accurately predict viewers' instantaneous subjective QoE under such volatile network conditions could potentially enable the more efficient design of quality-control protocols for media-driven services, such as YouTube, Amazon, Netflix, and so on. However, most existing models only predict a single overall QoE score on a given video and are based on simple global video features, without accounting for relevant aspects of human perception and behavior. We have created a QoE evaluator, called the time-varying QoE Indexer, that accounts for interactions between stalling events, analyzes the spatial and temporal content of a video, predicts the perceptual video quality, models the state of the client-side data buffer, and consequently predicts continuous-time quality scores that agree quite well with human opinion scores. The new QoE predictor also embeds the impact of relevant human cognitive factors, such as memory and recency, and their complex interactions with the video content being viewed. We evaluated the proposed model on three different video databases and attained standout QoE prediction performance.

  6. STREAM2016: Streaming Requirements, Experience, Applications and Middleware Workshop

    Energy Technology Data Exchange (ETDEWEB)

    Fox, Geoffrey [Indiana Univ., Bloomington, IN (United States); Jha, Shantenu [Rutgers Univ., New Brunswick, NJ (United States); Ramakrishnan, Lavanya [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2016-10-01

    The Department of Energy (DOE) Office of Science (SC) facilities including accelerators, light sources and neutron sources and sensors that study, the environment, and the atmosphere, are producing streaming data that needs to be analyzed for next-generation scientific discoveries. There has been an explosion of new research and technologies for stream analytics arising from the academic and private sectors. However, there has been no corresponding effort in either documenting the critical research opportunities or building a community that can create and foster productive collaborations. The two-part workshop series, STREAM: Streaming Requirements, Experience, Applications and Middleware Workshop (STREAM2015 and STREAM2016), were conducted to bring the community together and identify gaps and future efforts needed by both NSF and DOE. This report describes the discussions, outcomes and conclusions from STREAM2016: Streaming Requirements, Experience, Applications and Middleware Workshop, the second of these workshops held on March 22-23, 2016 in Tysons, VA. STREAM2016 focused on the Department of Energy (DOE) applications, computational and experimental facilities, as well software systems. Thus, the role of “streaming and steering” as a critical mode of connecting the experimental and computing facilities was pervasive through the workshop. Given the overlap in interests and challenges with industry, the workshop had significant presence from several innovative companies and major contributors. The requirements that drive the proposed research directions, identified in this report, show an important opportunity for building competitive research and development program around streaming data. These findings and recommendations are consistent with vision outlined in NRC Frontiers of Data and National Strategic Computing Initiative (NCSI) [1, 2]. The discussions from the workshop are captured as topic areas covered in this report's sections. The report

  7. Effects of Video Streaming Technology on Public Speaking Students' Communication Apprehension and Competence

    Science.gov (United States)

    Dupagne, Michel; Stacks, Don W.; Giroux, Valerie Manno

    2007-01-01

    This study examines whether video streaming can reduce trait and state communication apprehension, as well as improve communication competence, in public speaking classes. Video streaming technology has been touted as the next generation of video feedback for public speaking students because it is not limited by time or space and allows Internet…

  8. Questioning, Promoting and Evaluating the Use of Streaming Video To Support Student Learning.

    Science.gov (United States)

    Shephard, Kerry

    2003-01-01

    Uses case studies to describe how streaming video is currently used to support student learning in post-compulsory education in the United Kingdom. Describes the current role of streaming video and identifies processes that could extend the application of streaming in education. Identifies elements of a research agenda that could further develop…

  9. Efficient Video Streaming Scheme for Next Generations of Mobile Networks

    Directory of Open Access Journals (Sweden)

    Majdi Ashibani

    2005-04-01

    Full Text Available Video streaming over next generations of mobile networks has undergone enormous development recently due to the continuing growth in wireless communication, especially since the emergence of 3G wireless networks. The new generations of wireless networks pose many challenges, including supporting quality of service over wireless communication links. This is due to the time-varying characteristics of wireless channel. Therefore, a more flexible and efficient bandwidth allocation scheme is needed. This paper is a part of ongoing work to come up with a more robust scheme that is capable of rapidly adapting to changes in network conditions. The proposed scheme focuses on the wireless part of the network, providing high quality video service and better utilization of network resources.

  10. Software support for video streaming from smartphone on small airship

    OpenAIRE

    Carretero Rodríguez, Miguel

    2009-01-01

    This project has been created to study and to solve two goals. The main goal has been streaming real video from a smartphone to a laptop and the second goal has been to control the airship electronics from the smartphone. To achieve the main goal of the project, firstly has been necessary realize a technologies study to select the better choice. The chosen technology has been to use of wi-fi, mainly due to the high transmission speed. Once the technology has been chosen, an ad-hoc wi-fi netwo...

  11. Priority-based methods for reducing the impact of packet loss on HEVC encoded video streams

    Science.gov (United States)

    Nightingale, James; Wang, Qi; Grecos, Christos

    2013-02-01

    The rapid growth in the use of video streaming over IP networks has outstripped the rate at which new network infrastructure has been deployed. These bandwidth-hungry applications now comprise a significant part of all Internet traffic and present major challenges for network service providers. The situation is more acute in mobile networks where the available bandwidth is often limited. Work towards the standardisation of High Efficiency Video Coding (HEVC), the next generation video coding scheme, is currently on track for completion in 2013. HEVC offers the prospect of a 50% improvement in compression over the current H.264 Advanced Video Coding standard (H.264/AVC) for the same quality. However, there has been very little published research on HEVC streaming or the challenges of delivering HEVC streams in resource-constrained network environments. In this paper we consider the problem of adapting an HEVC encoded video stream to meet the bandwidth limitation in a mobile networks environment. Video sequences were encoded using the Test Model under Consideration (TMuC HM6) for HEVC. Network abstraction layers (NAL) units were packetized, on a one NAL unit per RTP packet basis, and transmitted over a realistic hybrid wired/wireless testbed configured with dynamically changing network path conditions and multiple independent network paths from the streamer to the client. Two different schemes for the prioritisation of RTP packets, based on the NAL units they contain, have been implemented and empirically compared using a range of video sequences, encoder configurations, bandwidths and network topologies. In the first prioritisation method the importance of an RTP packet was determined by the type of picture and the temporal switching point information carried in the NAL unit header. Packets containing parameter set NAL units and video coding layer (VCL) NAL units of the instantaneous decoder refresh (IDR) and the clean random access (CRA) pictures were given the

  12. Thermal imagers: from ancient analog video output to state-of-the-art video streaming

    Science.gov (United States)

    Haan, Hubertus; Feuchter, Timo; Münzberg, Mario; Fritze, Jörg; Schlemmer, Harry

    2013-06-01

    The video output of thermal imagers stayed constant over almost two decades. When the famous Common Modules were employed a thermal image at first was presented to the observer in the eye piece only. In the early 1990s TV cameras were attached and the standard output was CCIR. In the civil camera market output standards changed to digital formats a decade ago with digital video streaming being nowadays state-of-the-art. The reasons why the output technique in the thermal world stayed unchanged over such a long time are: the very conservative view of the military community, long planning and turn-around times of programs and a slower growth of pixel number of TIs in comparison to consumer cameras. With megapixel detectors the CCIR output format is not sufficient any longer. The paper discusses the state-of-the-art compression and streaming solutions for TIs.

  13. Streaming Videos in Peer Assessment to Support Training Pre-Service Teachers

    Science.gov (United States)

    Wu, Cheng-Chih; Kao, Hue-Ching

    2008-01-01

    A web-based peer assessment system using video streaming technology was implemented to support the training of pre-service teachers. The peer assessment process was synchronized with viewing of peer teaching videos so that comments could be linked to the relevant position on the video. When one viewed a comment, the associated video segment could…

  14. Videos of Basal Ice in Boreholes on the Kamb Ice Stream in West Antarctica, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set is a collection of video data of basal ice taken in a borehole on the Kamb Ice Stream in West Antarctica. Ice streams are an expression of the inherent...

  15. A modular video streaming method for surgical assistance in operating room networks.

    Science.gov (United States)

    Voruganti, Arun Kumar Raj; Mayoral, Rafael; Vazquez, Adrian; Burgert, Oliver

    2010-09-01

    Continuous video is used with increasing frequency in the operating room for minimally invasive laparoscopic and endoscopic procedures. Video data communication in the OR requires device interoperability, efficient data transfer methods, and specialized IT infrastructure. A framework for digital video communication based on a two channel client-server architecture was developed and tested. One channel is used for stream handling and the second channel is used for data streaming. A video stream description (VSD) specification is defined to negotiate video stream characteristics and ensure semantic interoperability. Quality assessment of the streamed data employs an image-based structural quality measure called the Structural Similarity (SSIM) Index. By introducing the stream description and a quality metric, the stream parameters can be modified as needed. The video communication framework ensures interoperability by defining interfaces for each of the streaming architecture modules. To prove the framework's feasibility, two prototype applications were developed and performance tests were performed on a dedicated OR network. The results showed acceptable network performance for streaming video in the OR network under clinically realistic conditions. An OR video communications framework was developed that uses existing OR network infrastructure as an economical alternative to dedicated integrated OR solutions. This framework provides functional and semantic interoperability among imaging modalities for continuous video data communication.

  16. Simulation and experimental testbed for adaptive video streaming in ad hoc networks

    OpenAIRE

    Gonzalez-Martinez, Santiago Renan; Castellanos Hernández, Wilder Eduardo; Guzman Castillo, Paola Fernanda; Arce Vila, Pau; Guerri Cebollada, Juan Carlos

    2016-01-01

    This paper presents a performance evaluation of the scalable video streaming over mobile ad hoc networks. In particular, we focus on the rate-adaptive method for streaming scalable video (H.264/SVC). For effective adaptation a new cross-layer routing protocol is introduced. This protocol provides an efficient algorithm for available bandwidth estimation. With this information, the video source adjusts its bit rate during the video transmission according to the network state. We also propose a...

  17. Study of Temporal Effects on Subjective Video Quality of Experience.

    Science.gov (United States)

    Bampis, Christos George; Zhi Li; Moorthy, Anush Krishna; Katsavounidis, Ioannis; Aaron, Anne; Bovik, Alan Conrad

    2017-11-01

    HTTP adaptive streaming is being increasingly deployed by network content providers, such as Netflix and YouTube. By dividing video content into data chunks encoded at different bitrates, a client is able to request the appropriate bitrate for the segment to be played next based on the estimated network conditions. However, this can introduce a number of impairments, including compression artifacts and rebuffering events, which can severely impact an end-user's quality of experience (QoE). We have recently created a new video quality database, which simulates a typical video streaming application, using long video sequences and interesting Netflix content. Going beyond previous efforts, the new database contains highly diverse and contemporary content, and it includes the subjective opinions of a sizable number of human subjects regarding the effects on QoE of both rebuffering and compression distortions. We observed that rebuffering is always obvious and unpleasant to subjects, while bitrate changes may be less obvious due to content-related dependencies. Transient bitrate drops were preferable over rebuffering only on low complexity video content, while consistently low bitrates were poorly tolerated. We evaluated different objective video quality assessment algorithms on our database and found that objective video quality models are unreliable for QoE prediction on videos suffering from both rebuffering events and bitrate changes. This implies the need for more general QoE models that take into account objective quality models, rebuffering-aware information, and memory. The publicly available video content as well as metadata for all of the videos in the new database can be found at http://live.ece.utexas.edu/research/LIVE_NFLXStudy/nflx_index.html.

  18. Streaming video to enhance students’ reflection in dance education

    NARCIS (Netherlands)

    Leijen, A.; Lam, I.; Wildschut, L.; Simons, P.R.J.; Admiraal, W.

    2009-01-01

    This paper presents an evaluation case study that describes the experiences of 15 students and 2 teachers using a video-based learning environment, DiViDU, to facilitate students’ daily reflection activities in a composition course and a ballet course. To support dance students’ reflection processes

  19. PET protection optimization for streaming scalable videos with multiple transmissions.

    Science.gov (United States)

    Xiong, Ruiqin; Taubman, David S; Sivaraman, Vijay

    2013-11-01

    This paper investigates priority encoding transmission (PET) protection for streaming scalably compressed video streams over erasure channels, for the scenarios where a small number of retransmissions are allowed. In principle, the optimal protection depends not only on the importance of each stream element, but also on the expected channel behavior. By formulating a collection of hypotheses concerning its own behavior in future transmissions, limited-retransmission PET (LR-PET) effectively constructs channel codes spanning multiple transmission slots and thus offers better protection efficiency than the original PET. As the number of transmission opportunities increases, the optimization for LR-PET becomes very challenging because the number of hypothetical retransmission paths increases exponentially. As a key contribution, this paper develops a method to derive the effective recovery-probability versus redundancy-rate characteristic for the LR-PET procedure with any number of transmission opportunities. This significantly accelerates the protection assignment procedure in the original LR-PET with only two transmissions, and also makes a quick and optimal protection assignment feasible for scenarios where more transmissions are possible. This paper also gives a concrete proof to the redundancy embedding property of the channel codes formed by LR-PET, which allows for a decoupled optimization for sequentially dependent source elements with convex utility-length characteristic. This essentially justifies the source-independent construction of the protection convex hull for LR-PET.

  20. Adaptive Bit Rate Video Streaming Through an RF/Free Space Optical Laser Link

    Directory of Open Access Journals (Sweden)

    A. Akbulut

    2010-06-01

    Full Text Available This paper presents a channel-adaptive video streaming scheme which adjusts video bit rate according to channel conditions and transmits video through a hybrid RF/free space optical (FSO laser communication system. The design criteria of the FSO link for video transmission to 2.9 km distance have been given and adaptive bit rate video streaming according to the varying channel state over this link has been studied. It has been shown that the proposed structure is suitable for uninterrupted transmission of videos over the hybrid wireless network with reduced packet delays and losses even when the received power is decreased due to weather conditions.

  1. Reliable Adaptive Video Streaming Driven by Perceptual Semantics for Situational Awareness.

    Science.gov (United States)

    Pimentel-Niño, M A; Saxena, Paresh; Vazquez-Castro, M A

    2015-01-01

    A novel cross-layer optimized video adaptation driven by perceptual semantics is presented. The design target is streamed live video to enhance situational awareness in challenging communications conditions. Conventional solutions for recreational applications are inadequate and novel quality of experience (QoE) framework is proposed which allows fully controlled adaptation and enables perceptual semantic feedback. The framework relies on temporal/spatial abstraction for video applications serving beyond recreational purposes. An underlying cross-layer optimization technique takes into account feedback on network congestion (time) and erasures (space) to best distribute available (scarce) bandwidth. Systematic random linear network coding (SRNC) adds reliability while preserving perceptual semantics. Objective metrics of the perceptual features in QoE show homogeneous high performance when using the proposed scheme. Finally, the proposed scheme is in line with content-aware trends, by complying with information-centric-networking philosophy and architecture.

  2. Reliable Adaptive Video Streaming Driven by Perceptual Semantics for Situational Awareness

    Science.gov (United States)

    Pimentel-Niño, M. A.; Saxena, Paresh; Vazquez-Castro, M. A.

    2015-01-01

    A novel cross-layer optimized video adaptation driven by perceptual semantics is presented. The design target is streamed live video to enhance situational awareness in challenging communications conditions. Conventional solutions for recreational applications are inadequate and novel quality of experience (QoE) framework is proposed which allows fully controlled adaptation and enables perceptual semantic feedback. The framework relies on temporal/spatial abstraction for video applications serving beyond recreational purposes. An underlying cross-layer optimization technique takes into account feedback on network congestion (time) and erasures (space) to best distribute available (scarce) bandwidth. Systematic random linear network coding (SRNC) adds reliability while preserving perceptual semantics. Objective metrics of the perceptual features in QoE show homogeneous high performance when using the proposed scheme. Finally, the proposed scheme is in line with content-aware trends, by complying with information-centric-networking philosophy and architecture. PMID:26247057

  3. Adaptive Streaming of Scalable Videos over P2PTV

    Directory of Open Access Journals (Sweden)

    Youssef Lahbabi

    2015-01-01

    Full Text Available In this paper, we propose a new Scalable Video Coding (SVC quality-adaptive peer-to-peer television (P2PTV system executed at the peers and at the network. The quality adaptation mechanisms are developed as follows: on one hand, the Layer Level Initialization (LLI is used for adapting the video quality with the static resources at the peers in order to avoid long startup times. On the other hand, the Layer Level Adjustment (LLA is invoked periodically to adjust the SVC layer to the fluctuation of the network conditions with the aim of predicting the possible stalls before their occurrence. Our results demonstrate that our mechanisms allow quickly adapting the video quality to various system changes while providing best Quality of Experience (QoE that matches current resources of the peer devices and instantaneous throughput available at the network state.

  4. An Approach to Streaming Video Segmentation With Sub-Optimal Low-Rank Decomposition.

    Science.gov (United States)

    Li, Chenglong; Lin, Liang; Zuo, Wangmeng; Wang, Wenzhong; Tang, Jin

    2016-05-01

    This paper investigates how to perform robust and efficient video segmentation while suppressing the effects of data noises and/or corruptions, and an effective approach is introduced to this end. First, a general algorithm, called sub-optimal low-rank decomposition (SOLD), is proposed to pursue the low-rank representation for video segmentation. Given the data matrix formed by supervoxel features of an observed video sequence, SOLD seeks a sub-optimal solution by making the matrix rank explicitly determined. In particular, the representation coefficient matrix with the fixed rank can be decomposed into two sub-matrices of low rank, and then we iteratively optimize them with closed-form solutions. Moreover, we incorporate a discriminative replication prior into SOLD based on the observation that small-size video patterns tend to recur frequently within the same object. Second, based on SOLD, we present an efficient inference algorithm to perform streaming video segmentation in both unsupervised and interactive scenarios. More specifically, the constrained normalized-cut algorithm is adopted by incorporating the low-rank representation with other low level cues and temporal consistent constraints for spatio-temporal segmentation. Extensive experiments on two public challenging data sets VSB100 and SegTrack suggest that our approach outperforms other video segmentation approaches in both accuracy and efficiency.

  5. Live streaming video for medical education: a laboratory model.

    Science.gov (United States)

    Gandsas, Alejandro; McIntire, Katherine; Palli, Guillermo; Park, Adrian

    2002-10-01

    At the University of Kentucky (UK), we applied streaming video technology to develop a webcast model that will allow institutions to broadcast live and prerecorded surgeries, conferences, and courses in real time over networks (the Internet or an intranet). We successfully broadcast a prerecorded laparoscopic paraesophageal hernia repair to domestic and international clients by using desktop computers equipped with off-the-shelf, streaming-enabled software and standard hardware and operating systems. A web-based user interface made accessing the educational material as simple as a mouse click and allowed clients to participate in the broadcast event via an embedded e-mail/chat module. Three client computers (two connected to the Internet and a third connected to the UK intranet) requested and displayed the surgical film by means of seven common network connection configurations. Significantly, no difference in image resolution was detected with the use of a connection speed faster than 128 kilobytes per second (kbps). At this connection speed, an average bandwidth of 32.7 kbps was used, and although a 15-second delay was experienced from the time of data request to data display, the surgical film streamed continuously from beginning to end at a mean rate of 14.4 frames per second (fps). The clients easily identified all anatomic structures in full color motion, clearly followed all steps of the surgical procedure, and successfully asked questions and made comments by using the e-mail/chat module while viewing the surgery. With minimal financial investment, we have created an interactive virtual classroom with the potential to attract a global audience. Our webcast model represents a simple and practical method for institutions to supplement undergraduate and graduate surgical education and offer continuing medical education credits in a way that is convenient for clients (surgeons, students, residents, others). In the future, physicians may access streaming webcast

  6. Using Video Streaming: Setting Up a Cheap System for Distributing Information to Teachers and Students

    Science.gov (United States)

    McNeal, Thomas, Jr.; Kearns, Landon

    2005-01-01

    Video streaming can be a very useful tool for educators. It is now possible for a school?s technical specialist or classroom teacher to create a streaming server with tools that are available in many classrooms. In this article we describe how we created our video streamer using free software, older computers, and borrowed hardware. The system…

  7. Streaming video - præsentation af trailere over internettet

    DEFF Research Database (Denmark)

    Jensen, Ole Riis; Forchhammer, Søren

    1998-01-01

    Som et led i Tele Danmark Kabel TV's markedsføring ønsker man at kunne præsentere filmtrailere og andet materiale i form af levende billeder til kunderne via Wold Wide Web (WWW). Dette projekts hovedformål er at undersøge eksisterende metoder og udvikle redskaber til at præsentere en tilsvarende ...... interaktiv tjeneste baseret på realtidsfremvisning af videotrailere, såkaldt streaming video og audio, og hvor brugeren kan få information om en film der tænkes udbudt på en pay-per-view kanal. Der i arbejdets forløb blevet opbygget en demo, der implementerer en sådan tjeneste....

  8. Joint Optimized CPU and Networking Control Scheme for Improved Energy Efficiency in Video Streaming on Mobile Devices

    Directory of Open Access Journals (Sweden)

    Sung-Woong Jo

    2017-01-01

    Full Text Available Video streaming service is one of the most popular applications for mobile users. However, mobile video streaming services consume a lot of energy, resulting in a reduced battery life. This is a critical problem that results in a degraded user’s quality of experience (QoE. Therefore, in this paper, a joint optimization scheme that controls both the central processing unit (CPU and wireless networking of the video streaming process for improved energy efficiency on mobile devices is proposed. For this purpose, the energy consumption of the network interface and CPU is analyzed, and based on the energy consumption profile a joint optimization problem is formulated to maximize the energy efficiency of the mobile device. The proposed algorithm adaptively adjusts the number of chunks to be downloaded and decoded in each packet. Simulation results show that the proposed algorithm can effectively improve the energy efficiency when compared with the existing algorithms.

  9. Evaluation of an interactive web-based nursing course with streaming videos for medication administration skills.

    Science.gov (United States)

    Sowan, Azizeh K; Idhail, Jamila Abu

    2014-08-01

    Nursing students should exhibit competence in nursing skills in order to provide safe and quality patient care. This study describes the design and students' response to an interactive web-based course using streaming video technology tailored to students' needs and the course objectives of the fundamentals of nursing skills clinical course. A mixed-methodology design was used to describe the experience of 102 first-year undergraduate nursing students at a school of nursing in Jordan who were enrolled in the course. A virtual course with streaming videos was designed to demonstrate medication administration fundamental skills. The videos recorded the ideal lab demonstration of the skills, and real-world practice performed by registered nurses for patients in a hospital setting. After course completion, students completed a 30-item satisfaction questionnaire, 8 self-efficacy scales, and a 4-item scale solicited their preferences of using the virtual course as a substitute or a replacement of the lab demonstration. Students' grades in the skill examination of the procedures were measured. Relationships between the main variables and predictors of satisfaction and self-efficacy were examined. Students were satisfied with the virtual course (3.9 ± 0.56, out of a 5-point scale) with a high-perceived overall self-efficacy (4.38 ± 0.42, out of a 5-point scale). Data showed a significant correlation between student satisfaction, self-efficacy and achievement in the virtual course (r = 0.45-0.49, p streaming videos for clinical courses is a complex process that should be carefully designed to positively influence the learning experience. However, the learning benefits gained from such pedagogical approach are worth faculty, institution and students' efforts. Published by Elsevier Ireland Ltd.

  10. A Stream Tapping Protocol Involving Clients in the Distribution of Videos on Demand

    Directory of Open Access Journals (Sweden)

    Santosh Kulkarni

    2008-01-01

    Full Text Available We present a stream tapping protocol that involves clients in the video distribution process. As in conventional stream tapping, our protocol allows new clients to tap the most recent broadcast of the video they are watching. While conventional stream tapping required the server to send to these clients the part of the video they missed, our protocol delegates this task to the clients that are already watching the video, thus greatly reducing the workload of the server. Unlike previous solutions involving clients in the video distribution process, our protocol works with clients that can only upload video data at a fraction of the video consumption rate and includes a mechanism to control its network bandwidth consumption.

  11. The Use of Streamed Lecture Recordings: Patterns of Use, Student Experience and Effects on Learning Outcomes

    Science.gov (United States)

    Engstrand, Susan M.; Hall, Susanne

    2011-01-01

    We describe a study conducted during 2008-2009 that investigated three issues relating to the use of streamed video recordings of classes by students at the University of the Highlands and Islands. We investigated (i) the pattern of use of the resource, (ii) the student experience and (iii) the impact of watching the streamed classes on learning…

  12. Analisis Kualitas Layanan Video Live Streaming pada Jaringan Lokal Universitas Telkom

    Directory of Open Access Journals (Sweden)

    Anggelina I Diwi

    2014-09-01

    Full Text Available Streaming adalah salah satu bentuk teknologi yang memperkenankan file digunakan secara langsung tanpa menunggu selesainya unggahan (download dan berlangsung secara kontinyu tanpa interupsi. Untuk mengaplikasikan video streaming kedalam jaringan, diperlukan pertama-tama untuk mengkalkulasi bandwidth yang tersedia, untuk mendukung transmisi data. Bandwidth merupakan parameter penting untuk streaming di dalam jaringan. Makin besar bandwidth yang tersedia, makin baik kualitas video yang ditampilkan. Penelitian ini bertujuan untuk mengetahui kebutuhan bandwidth untuk layanan video live streaming; metode yang digunakan di dalam penelitian ini adalah dengan mengadakan pengukuran unjuk kerja jaringan secara langsung di lapangan, yaitu LAN di lingkungan Universitas Telkom. Implementasi media streaming server-client di dalam penelitian ini menggunakan file video yang berbeda, berdasarkan jumlah frame yang dikirim (fps. Skenario video streaming ini dilakukan dengan menggunakan latar belakang  trafik  yang  bervariasi,  untuk  melihat  pengaruhnya terhadap parameter QoS jaringan. Pengujian performansi Quality of Service (QoS dalam implementasi video live streaming ini menggunakan software network analyzer Wireshark. Hasil penilitian menunjukkan, bahwa video dengan laju frame lebih besar dari 15 fps, memberikan jitter dan throughput yang besar pula.

  13. 4kUHD H264 Wireless Live Video Streaming Using CUDA

    Directory of Open Access Journals (Sweden)

    A. O. Adeyemi-Ejeye

    2014-01-01

    Full Text Available Ultrahigh definition video streaming has been explored in recent years. Most recently the possibility of 4kUHD video streaming over wireless 802.11n was presented, using preencoded video. Live encoding for streaming using x264 has proven to be very slow. The use of parallel encoding has been explored to speed up the process using CUDA. However there hasnot been a parallel implementation for video streaming. We therefore present for the first time a novel implementation of 4kUHD live encoding for streaming over a wireless network at low bitrate indoors, using CUDA for parallel H264 encoding. Our experimental results are used to verify our claim.

  14. Visual saliency in MPEG-4 AVC video stream

    Science.gov (United States)

    Ammar, M.; Mitrea, M.; Hasnaoui, M.; Le Callet, P.

    2015-03-01

    Visual saliency maps already proved their efficiency in a large variety of image/video communication application fields, covering from selective compression and channel coding to watermarking. Such saliency maps are generally based on different visual characteristics (like color, intensity, orientation, motion,…) computed from the pixel representation of the visual content. This paper resumes and extends our previous work devoted to the definition of a saliency map solely extracted from the MPEG-4 AVC stream syntax elements. The MPEG-4 AVC saliency map thus defined is a fusion of static and dynamic map. The static saliency map is in its turn a combination of intensity, color and orientation features maps. Despite the particular way in which all these elementary maps are computed, the fusion techniques allowing their combination plays a critical role in the final result and makes the object of the proposed study. A total of 48 fusion formulas (6 for combining static features and, for each of them, 8 to combine static to dynamic features) are investigated. The performances of the obtained maps are evaluated on a public database organized at IRCCyN, by computing two objective metrics: the Kullback-Leibler divergence and the area under curve.

  15. Action video game experience affects oculomotor performance.

    Science.gov (United States)

    West, Greg L; Al-Aidroos, Naseem; Pratt, Jay

    2013-01-01

    Action video games have been show to affect a variety of visual and cognitive processes. There is, however, little evidence of whether playing video games can also affect motor action. To investigate the potential link between experience playing action video games and changes in oculomotor action, we tested habitual action video game players (VGPs) and non-video game players (NVGPs) in a saccadic trajectory deviation task. We demonstrate that spatial curvature of a saccadic trajectory towards or away from distractor is profoundly different between VGPs and NVGPs. In addition, task performance accuracy improved over time only in VGPs. Results are discussed in the context of the competing interplay between stimulus-driven motor programming and top-down inhibition during oculomotor execution. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. Optimal PET protection for streaming scalably compressed video streams with limited retransmission based on incomplete feedback.

    Science.gov (United States)

    Xiong, Ruiqin; Taubman, David; Sivaraman, Vijay

    2010-09-01

    For streaming scalably compressed video streams over unreliable networks, Limited-Retransmission Priority Encoding Transmission (LR-PET) outperforms PET remarkably since the opportunity to retransmit is fully exploited by hypothesizing the possible future retransmission behavior before the retransmission really occurs. For the retransmission to be efficient in such a scheme, it is critical to get adequate acknowledgment from a previous transmission before deciding what data to retransmit. However, in many scenarios, the presence of a stochastic packet delay process results in frequent late acknowledgements, while imperfect feedback channels can impair the server's knowledge of what the client has received. This paper proposes an extended LR-PET scheme, which optimizes PET-protection of transmitted bitstreams, recognizing that the received feedback information is likely to be incomplete. Similar to the original LR-PET, the behavior of future retransmissions is hypothesized in the optimization objective of each transmission opportunity. As the key contribution, we develop a method to efficiently derive the effective recovery probability versus redundancy rate characteristic for the extended LR-PET communication process. This significantly simplifies the ultimate protection assignment procedure. This paper also demonstrates the advantage of the proposed strategy over several alternative strategies.

  17. Evaluation of MPEG-4 video streaming over UMTS/WCDMA dedicated channels

    NARCIS (Netherlands)

    Lo, Anthony; Heijenk, Geert; Niemegeers, I.G.M.M.

    2005-01-01

    Universal Mobile Telecommunications System (UMTS) is a third-generation mobile communication system that supports wireless wideband multimedia communications. This paper investigates the performance of streaming MPEG-4 video over UMTS dedicated channels with varying channel conditions. In order to

  18. Enhancing the quality of service of video streaming over MANETs using MDC and FEC

    Science.gov (United States)

    Zang, Weihua; Guo, Rui

    2012-04-01

    Path and server diversities have been used to guarantee reliable video streaming communication over wireless networks. In this paper, server diversity over mobile wireless ad hoc networks (MANETs) is implemented. Particularly, multipoint-to-point transmission together with multiple description coding (MDC) and forward error correction (FEC) technique is used to enhance the quality of service of video streaming over the wireless lossy networks. Additionally, the dynamic source routing (DSR) protocol is used to discover maximally disjoint routes for each sender and to distribute the workload evenly within the MANETs for video streaming applications. NS-2 Simulation study demonstrates the feasibility of the proposed mechanism and it shows that the approach achieves better quality of video streaming, in terms of the playable frame rate, reliability and real-time performance on the receiving side.

  19. Stream On: Video Servers in the Real World.

    Science.gov (United States)

    Tristram, Claire

    1995-01-01

    Despite plans for corporate training networks, digital ad-insertion systems, hotel video-on-demand, and interactive television, only small scale video networks presently work. Four case studies examine the design and implementation decisions for different markets: corporate; advertising; hotel; and commercial video via cable, satellite or…

  20. Effect of embedded streaming video strategy in an online learning environment on the learning of neuroscience

    Science.gov (United States)

    Tantrarungroj, Pornsook

    The purpose of this study was to investigate the effectiveness of the embedded streaming video strategy in an online learning environment on declarative knowledge learning of neuroscience. The design used in this study was the posttest-only control-group design. A sample of 92 undergraduate students from a Midwestern university was recruited for the study. The students in the experimental group received online text-based instruction with static graphics and embedded streaming video, while the control group received the online text-based instruction with static graphics. No significant difference in students' immediate learning performance was found as measured by the content-related immediate posttest; however, a significant difference was found in students' knowledge retention as measured by the content-related retention posttest. The student' perception of the effectiveness of streaming video according to gender was also administered by the web-form survey. No significant gender difference was found to exist in students' perceptions toward the effectiveness of embedded streaming video. Results of the web-form survey of respondents' attitude regarding the effectiveness of streaming video are also presented. Adding streaming video to the online learning environment is recommended as one way to increase student learning performance.

  1. The effectiveness of streaming video on medical student learning: a case study.

    Science.gov (United States)

    Bridge, Patrick D; Jackson, Matt; Robinson, Leah

    2009-08-19

    Information technology helps meet today's medical students' needs by providing multiple curriculum delivery methods. Video streaming is an e-learning technology that uses the Internet to deliver curriculum while giving the student control of the content's delivery. There have been few studies conducted on the effectiveness of streaming video in medical schools. A 5-year retrospective study was conducted using three groups of students (n = 1736) to determine if the availability of streaming video in Years 1-2 of the basic science curriculum affected overall Step 1 scores for first-time test-takers. The results demonstrated a positive effect on program outcomes as streaming video became more readily available to students. Based on these findings, streaming video technology seems to be a viable tool to complement in-class delivery methods, to accommodate the needs of medical students, and to provide options for meeting the challenges of delivering the undergraduate medical curriculum. Further studies need to be conducted to continue validating the effectiveness of streaming video technology.

  2. Energy saving approaches for video streaming on smartphone based on QoE modeling

    DEFF Research Database (Denmark)

    Ballesteros, Luis Guillermo Martinez; Ickin, Selim; Fiedler, Markus

    2016-01-01

    In this paper, we study the influence of video stalling on QoE. We provide QoE models that are obtained in realistic scenarios on the smartphone, and provide energy-saving approaches for smartphone by leveraging the proposed QoE models in relation to energy. Results show that approximately 5J...... is saved in a 3 minutes video clip with an acceptable Mean Opinion Score (MOS) level when the video frames are skipped. If the video frames are not skipped, then it is suggested to avoid freezes during a video stream as the freezes highly increase the energy waste on the smartphones....

  3. Performance Evaluation of Concurrent Multipath Video Streaming in Multihomed Mobile Networks

    Directory of Open Access Journals (Sweden)

    James Nightingale

    2013-01-01

    Full Text Available High-quality real-time video streaming to users in mobile networks is challenging due to the dynamically changing nature of the network paths, particularly the limited bandwidth and varying end-to-end delay. In this paper, we empirically investigate the performance of multipath streaming in the context of multihomed mobile networks. Existing schemes that make use of the aggregated bandwidth of multiple paths can overcome bandwidth limitations on a single path but suffer an efficiency penalty caused by retransmission of lost packets in reliable transport schemes or path switching overheads in unreliable transport schemes. This work focuses on the evaluation of schemes to permit concurrent use of multiple paths to deliver video streams. A comprehensive streaming framework for concurrent multipath video streaming is proposed and experimentally evaluated, using current state-of-the-art H.264 Scalable Video Coding (H.264/SVC and the next generation High Efficiency Video Coding (HEVC standards. It provides a valuable insight into the benefit of using such schemes in conjunction with encoder specific packet prioritisation mechanisms for quality-aware packet scheduling and scalable streaming. The remaining obstacles to deployment of concurrent multipath schemes are identified, and the challenges in realising HEVC based concurrent multipath streaming are highlighted.

  4. A Scalable Multimedia Streaming Scheme with CBR-Transmission of VBR-Encoded Videos over the Internet

    Science.gov (United States)

    Kabir, Md. H.; Shoja, Gholamali C.; Manning, Eric G.

    2006-01-01

    Streaming audio/video contents over the Internet requires large network bandwidth and timely delivery of media data. A streaming session is generally long and also needs a large I/O bandwidth at the streaming server. A streaming server, however, has limited network and I/O bandwidth. For this reason, a streaming server alone cannot scale a…

  5. An analysis of technology usage for streaming digital video in support of a preclinical curriculum.

    Science.gov (United States)

    Dev, P; Rindfleisch, T C; Kush, S J; Stringer, J R

    2000-01-01

    Usage of streaming digital video of lectures in preclinical courses was measured by analysis of the data in the log file maintained on the web server. We observed that students use the video when it is available. They do not use it to replace classroom attendance but rather for review before examinations or when a class has been missed. Usage of video has not increased significantly for any course within the 18 month duration of this project.

  6. Impact of the LTE scheduler on achieving good QoE for DASH video streaming

    OpenAIRE

    Zahran, Ahmed H.; Quinlan, Jason J.; Ramakrishnan, K. K.; Sreenan, Cormac J.

    2016-01-01

    Dynamic adaptive video over HTTP (DASH) is fast becoming the protocol of choice for content providers for their online video streaming delivery. Concurrently, dependence on cellular Long Term Evolution (LTE) networks is growing to serve user demands for bandwidth-hungry applications, especially video. Each LTE base station's (eNodeB) scheduler assigns wireless resources to individual clients. Several alternative schedulers have been proposed, especially to meet the user's desired quality of e...

  7. A QoE Aware Fairness Bi-level Resource Allocation Algorithm for Multiple Video Streaming in WLAN

    Directory of Open Access Journals (Sweden)

    Hu Zhou

    2015-11-01

    Full Text Available With the increasing of smart devices such as mobile phones and tablets, the scenario of multiple video users watching video streaming simultaneously in one wireless local area network (WLAN becomes more and more popular. However, the quality of experience (QoE and the fairness among multiple users are seriously impacted by the limited bandwidth and shared resources of WLAN. In this paper, we propose a novel bi-level resource allocation algorithm. To maximize the total throughput of the network, the WLAN is firstly tuned to the optimal operation point. Then the wireless resource is carefully allocated at the first level, i.e., between AP and uplink background traffic users, and the second level, i.e., among downlink video users. The simulation results show that the proposed algorithm can guarantee the QoE and the fairness for all the video users, and there is little impact on the average throughput of the background traffic users.

  8. Fine-Grained Rate Shaping for Video Streaming over Wireless Networks

    Directory of Open Access Journals (Sweden)

    Chen Tsuhan

    2004-01-01

    Full Text Available Video streaming over wireless networks faces challenges of time-varying packet loss rate and fluctuating bandwidth. In this paper, we focus on streaming precoded video that is both source and channel coded. Dynamic rate shaping has been proposed to “shape” the precompressed video to adapt to the fluctuating bandwidth. In our earlier work, rate shaping was extended to shape the channel coded precompressed video, and to take into account the time-varying packet loss rate as well as the fluctuating bandwidth of the wireless networks. However, prior work on rate shaping can only adjust the rate oarsely. In this paper, we propose “fine-grained rate shaping (FGRS” to allow for bandwidth adaptation over a wide range of bandwidth and packet loss rate in fine granularities. The video is precoded with fine granularity scalability (FGS followed by channel coding. Utilizing the fine granularity property of FGS and channel coding, FGRS selectively drops part of the precoded video and still yields decodable bit-stream at the decoder. Moreover, FGRS optimizes video streaming rather than achieves heuristic objectives as conventional methods. A two-stage rate-distortion (RD optimization algorithm is proposed for FGRS. Promising results of FGRS are shown.

  9. User-adaptive mobile video streaming using MPEG-DASH

    Science.gov (United States)

    Reznik, Yuriy A.

    2013-09-01

    We describe an implementation of DASH streaming client for mobile devices which uses adaptation to user behavior and viewing conditions as means for improving efficiency of streaming delivery. Proposed design relies on sensors in a mobile device to detect presence of the user, his proximity to the screen, and other factors such as motion, brightness of the screen and ambient lighting conditions. This information is subsequently used to select stream that delivers adequate resolution implied by viewing conditions and natural limits of human vision. We show that in a mobile environment such adaptation can result in significant reduction of bandwidth usage compared to traditional streaming systems.

  10. A multichannel multi-encoding transmission scheme for wireless video streaming

    Science.gov (United States)

    Kolekar, Abhijeet; Feng, Wuchi; Venkatachalam, Muthaiah

    2007-01-01

    The wireless industry has seen a surge of interest in upcoming broadband wireless access (BWA) networks like WiMAX that are based on orthogonal frequency division multiplexing (OFDM). These wireless access technologies have several key features such as centralized scheduling, fine-grained allocation of transmission slots, adaptation of the modulation and coding schemes (MCS) to the SNR variations of the wireless channel, flexible and connection oriented MAC layer as well as QoS awareness and differentiation for applications. As a result, such architectures provide new opportunities for cross-layer optimization, particularly for applications that can tolerate some bit errors. In this paper, we describe a multi-channel video streaming protocol for video streaming over such networks. In addition, we propose a new combined channel coding and proportional share allocation scheme for multicast video distribution based upon a video's popularity. Our results show that we can more efficiently allocate network bandwidth while providing high quality video to the application.

  11. A novel ingress node design for video streaming over optical burst switching networks.

    Science.gov (United States)

    Askar, S; Zervas, G; Hunter, D K; Simeonidou, D

    2011-12-12

    This paper introduces a novel ingress node design which takes advantage of video data partitioning in order to deliver enhanced video streaming quality when using H.264/AVC codec over optical burst switching networks. Ns2 simulations show that the proposed scheme delivers improved video traffic quality without affecting other traffic, such as best effort traffic. Although the extra network load is comparatively small, the average gain in video PSNR was 5 dB over existing burst cloning schemes, with a maximum end-to-end delay of 17 ms, and jitter of less than 0.35 ms. © 2011 Optical Society of America

  12. An Introduction to Recording, Editing, and Streaming Picture-in-Picture Ultrasound Videos.

    Science.gov (United States)

    Rajasekaran, Sathish; Hall, Mederic M; Finnoff, Jonathan T

    2016-08-01

    This paper describes the process by which high-definition resolution (up to 1920 × 1080 pixels) ultrasound video can be captured in conjunction with high-definition video of the transducer position (picture-in-picture). In addition, we describe how to edit the recorded video feeds to combine both feeds, and to crop, resize, split, stitch, cut, annotate videos, and also change the frame rate, insert pictures, edit the audio feed, and use chroma keying. We also describe how to stream a picture-in-picture ultrasound feed during a videoconference. Copyright © 2016 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

  13. 360° video cloud streaming & HTMLVideoElement extensions: Presentation held at W3C Workshop on Web & Virtual Reality, October 19-20, 2016, San Jose, Calif., USA

    OpenAIRE

    Bassbouss, Louay

    2016-01-01

    Presented in the "360° video on the Web" Session: 360° video on the Web session identified needs for evolutions in streaming infrastructure (both on server and client side) to adapt to the heavy needs of 360° content streaming, and build understanding on what changes are needed to HTML media interfaces to make them suitable for 360° media content. In this presentation, a proof-of-concept 360° video cloud streaming solution that enables high quality 360° video experience on low capability devi...

  14. Proxy-assisted multicasting of video streams over mobile wireless networks

    Science.gov (United States)

    Nguyen, Maggie; Pezeshkmehr, Layla; Moh, Melody

    2005-03-01

    This work addresses the challenge of providing seamless multimedia services to mobile users by proposing a proxy-assisted multicast architecture for delivery of video streams. We propose a hybrid system of streaming proxies, interconnected by an application-layer multicast tree, where each proxy acts as a cluster head to stream out content to its stationary and mobile users. The architecture is based on our previously proposed Enhanced-NICE protocol, which uses an application-layer multicast tree to deliver layered video streams to multiple heterogeneous receivers. We targeted the study on placements of streaming proxies to enable efficient delivery of live and on-demand video, supporting both stationary and mobile users. The simulation results are evaluated and compared with two other baseline scenarios: one with a centralized proxy system serving the entire population and one with mini-proxies each to serve its local users. The simulations are implemented using the J-SIM simulator. The results show that even though proxies in the hybrid scenario experienced a slightly longer delay, they had the lowest drop rate of video content. This finding illustrates the significance of task sharing in multiple proxies. The resulted load balancing among proxies has provided a better video quality delivered to a larger audience.

  15. Two-Stream Transformer Networks for Video-based Face Alignment.

    Science.gov (United States)

    Liu, Hao; Lu, Jiwen; Feng, Jianjiang; Zhou, Jie

    2017-08-01

    In this paper, we propose a two-stream transformer networks (TSTN) approach for video-based face alignment. Unlike conventional image-based face alignment approaches which cannot explicitly model the temporal dependency in videos and motivated by the fact that consistent movements of facial landmarks usually occur across consecutive frames, our TSTN aims to capture the complementary information of both the spatial appearance on still frames and the temporal consistency information across frames. To achieve this, we develop a two-stream architecture, which decomposes the video-based face alignment into spatial and temporal streams accordingly. Specifically, the spatial stream aims to transform the facial image to the landmark positions by preserving the holistic facial shape structure. Accordingly, the temporal stream encodes the video input as active appearance codes, where the temporal consistency information across frames is captured to help shape refinements. Experimental results on the benchmarking video-based face alignment datasets show very competitive performance of our method in comparisons to the state-of-the-arts.

  16. Quality-aware Content Adaptation in Digital Video Streaming

    OpenAIRE

    Wilk, Stefan

    2016-01-01

    User-generated video has attracted a lot of attention due to the success of Video Sharing Sites such as YouTube and Online Social Networks. Recently, a shift towards live consumption of these videos is observable. The content is captured and instantly shared over the Internet using smart mobile devices such as smartphones. Large-scale platforms arise such as YouTube.Live, YouNow or Facebook.Live which enable the smartphones of users to livestream to the public. These platforms achieve the dis...

  17. Dynamic Programming Optimization of Multi-rate Multicast Video-Streaming Services

    Directory of Open Access Journals (Sweden)

    Nestor Michael Caños Tiglao

    2010-06-01

    Full Text Available In large scale IP Television (IPTV and Mobile TV distributions, the video signal is typically encoded and transmitted using several quality streams, over IP Multicast channels, to several groups of receivers, which are classified in terms of their reception rate. As the number of video streams is usually constrained by both the number of TV channels and the maximum capacity of the content distribution network, it is necessary to find the selection of video stream transmission rates that maximizes the overall user satisfaction. In order to efficiently solve this problem, this paper proposes the Dynamic Programming Multi-rate Optimization (DPMO algorithm. The latter was comparatively evaluated considering several user distributions, featuring different access rate patterns. The experimental results reveal that DPMO is significantly more efficient than exhaustive search, while presenting slightly higher execution times than the non-optimal Multi-rate Step Search (MSS algorithm.

  18. A Complexity-Aware Video Adaptation Mechanism for Live Streaming Systems

    Directory of Open Access Journals (Sweden)

    Chen Homer H

    2007-01-01

    Full Text Available The paradigm shift of network design from performance-centric to constraint-centric has called for new signal processing techniques to deal with various aspects of resource-constrained communication and networking. In this paper, we consider the computational constraints of a multimedia communication system and propose a video adaptation mechanism for live video streaming of multiple channels. The video adaptation mechanism includes three salient features. First, it adjusts the computational resource of the streaming server block by block to provide a fine control of the encoding complexity. Second, as far as we know, it is the first mechanism to allocate the computational resource to multiple channels. Third, it utilizes a complexity-distortion model to determine the optimal coding parameter values to achieve global optimization. These techniques constitute the basic building blocks for a successful application of wireless and Internet video to digital home, surveillance, IPTV, and online games.

  19. Using the Periscope Live Video-Streaming Application for Global Pathology Education: A Brief Introduction.

    Science.gov (United States)

    Fuller, Maren Y; Mukhopadhyay, Sanjay; Gardner, Jerad M

    2016-07-21

    Periscope is a live video-streaming smartphone application (app) that allows any individual with a smartphone to broadcast live video simultaneously to multiple smartphone users around the world. The aim of this review is to describe the potential of this emerging technology for global pathology education. To our knowledge, since the launch of the Periscope app (2015), only a handful of educational presentations by pathologists have been streamed as live video via Periscope. This review includes links to these initial attempts, a step-by-step guide for those interested in using the app for pathology education, and a summary of the pros and cons, including ethical/legal issues. We hope that pathologists will appreciate the potential of Periscope for sharing their knowledge, expertise, and research with a live (and potentially large) audience without the barriers associated with traditional video equipment and standard classroom/conference settings.

  20. Content-Adaptive Packetization and Streaming of Wavelet Video over IP Networks

    Directory of Open Access Journals (Sweden)

    Chien-Peng Ho

    2007-03-01

    Full Text Available This paper presents a framework of content-adaptive packetization scheme for streaming of 3D wavelet-based video content over lossy IP networks. The tradeoff between rate and distortion is controlled by jointly adapting scalable source coding rate and level of forward error correction (FEC protection. A content dependent packetization mechanism with data-interleaving and Reed-Solomon protection for wavelet-based video codecs is proposed to provide unequal error protection. This paper also tries to answer an important question for scalable video streaming systems: given extra bandwidth, should one increase the level of channel protection for the most important packets, or transmit more scalable source data? Experimental results show that the proposed framework achieves good balance between quality of the received video and level of error protection under bandwidth-varying lossy IP networks.

  1. Content-Adaptive Packetization and Streaming of Wavelet Video over IP Networks

    Directory of Open Access Journals (Sweden)

    Ho Chien-Peng

    2007-01-01

    Full Text Available This paper presents a framework of content-adaptive packetization scheme for streaming of 3D wavelet-based video content over lossy IP networks. The tradeoff between rate and distortion is controlled by jointly adapting scalable source coding rate and level of forward error correction (FEC protection. A content dependent packetization mechanism with data-interleaving and Reed-Solomon protection for wavelet-based video codecs is proposed to provide unequal error protection. This paper also tries to answer an important question for scalable video streaming systems: given extra bandwidth, should one increase the level of channel protection for the most important packets, or transmit more scalable source data? Experimental results show that the proposed framework achieves good balance between quality of the received video and level of error protection under bandwidth-varying lossy IP networks.

  2. Error Protection of Wavelet Scalable Video Streaming Using Wyner-Ziv Technique over a Lossy Network

    Science.gov (United States)

    Liu, Benjian; Xu, Ke

    This paper presents a novel error resilience scheme for wavelet scalable video coding. We use Wyner-Ziv codec to produce extra bits protecting the important parts of the embedded video streaming. At the same time these bits also as the second description of important parts are transmitted over auxiliary channel to the receiver for error resilience. The errors in the embedded video streaming can be corrected by Wyner-Ziv description which regards the decoded frame as side information. Moreover, Wyner-Ziv decoder utilizes a coarse estimated version of the corrupted parts exploiting frame correlation in wavelet video decoder to generate a refine version. Simulation results show that our proposed method can achieve much better performance compared with Forward Error Correction code. Meanwhile, this error resilient algorithm can achieve 2-3 dB PSNR gains over the motion compensation error concealment.

  3. A cross-layer approach for wireless medical video streaming in robotic teleultrasonography.

    Science.gov (United States)

    Martini, Maria G; Istepanian, Robert S H; Mazzotti, Matteo; Philip, Nada

    2007-01-01

    M-health is an emerging area of research integrating emerging wireless technologies with healthcare systems. One of the key challenges in future research in this area, especially from the communications perspective, is medical video streaming over 3G and 4G systems. In this paper, video streaming in a robotic teleultrasonography system through a cross-layer approach based on tailor made controller structures is presented. Simulation results of the proposed system demonstrate the successful performance of the proposed controller structures in this advanced mobile telemedical environment.

  4. Reboot-based Recovery of Performance Anomalies in Adaptive Bitrate Video-Streaming Services

    OpenAIRE

    Cunha, Carlos Augusto da Silva; Silva, Luis M. e

    2015-01-01

    Performance anomalies represent one common type of failures in Internet servers. Overcoming these failures without introducing server downtimes is of the utmost importance in video-streaming services. These services have large user abandon- ment costs when failures occur after users watch a significant part of a video. Reboot is the most popular and effective technique for overcoming performance anomalies but it takes several minutes from start until the...

  5. Frame Rate Exclusive Sync Management of Live Video Streams in Collaborative Mobile Production Environment

    OpenAIRE

    Mughal, Mudassar Ahmad; Zoric, Goranka; Juhlin, Oskar

    2014-01-01

    We discuss synchronization problem in an emerging type of multimedia applications, called live mobile collaborative video production systems. The mobile character of the production system allows a director to be present at the site where he/she can see the event directly as well as through the mixer display. In such a situation production of a consistent broadcast is sensitive to delay and asynchrony of video streams in the mixer console. In this paper, we propose an algorithm for this situat...

  6. TAG: A tree-assisted gossip protocol for on-demand video streaming

    OpenAIRE

    Zhou, Ming

    2005-01-01

    While a tree topology is often advocated for overlay video streaming due to its scalability, it suffers from discontinuous playback under highly dynamic network environments. On the other hand, gossip protocols using random message dissemination, though robust, fail to meet the real-time constraints for streaming applications. In this master thesis, I proposed TAG, a Tree-Assisted Gossip protocol, which adopts a tree structure with time indexing to accommodate asynchronous requests, and an ef...

  7. Low Delay Video Streaming on the Internet of Things Using Raspberry Pi

    Directory of Open Access Journals (Sweden)

    Ulf Jennehag

    2016-09-01

    Full Text Available The Internet of Things is predicted to consist of over 50 billion devices aiming to solve problems in most areas of our digital society. A large part of the data communicated is expected to consist of various multimedia contents, such as live audio and video. This article presents a solution for the communication of high definition video in low-delay scenarios (<200 ms under the constraints of devices with limited hardware resources, such as the Raspberry Pi. We verify that it is possible to enable low delay video streaming between Raspberry Pi devices using a distributed Internet of Things system called the SensibleThings platform. Specifically, our implementation transfers a 6 Mbps H.264 video stream of 1280 × 720 pixels at 25 frames per second between devices with a total delay of 181 ms on the public Internet, of which the overhead of the distributed Internet of Things communication platform only accounts for 18 ms of this delay. We have found that the most significant bottleneck of video transfer on limited Internet of Things devices is the video coding and not the distributed communication platform, since the video coding accounts for 90% of the total delay.

  8. Understanding the Perceptions of Network Gatekeepers on Bandwidth and Online Video Streams in Ahmadu Bello University, Nigeria

    Science.gov (United States)

    Odigie, Imoisili Ojeime; Gbaje, Ezra Shiloba

    2017-01-01

    Online video streaming is a learning technology used in today's world and reliant on the availability of bandwidth. This research study sought to understand the perceptions of network gatekeepers about bandwidth and online video streams in Ahmadu Bello University, Nigeria. To achieve this, the interpretive paradigm and the Network Gatekeeping…

  9. Guest Editorial: Analysis and Retrieval of Events/Actions and Workflows in Video Streams

    DEFF Research Database (Denmark)

    Doulamis, Anastasios; Doulamis, Nikolaos; Bertini, Marco

    2016-01-01

    Cognitive video supervision and event analysis in video sequences is a critical task in many multimedia applications. Methods, tools, and algorithms that aim to detect and recognize high-level concepts and their respective spatiotemporal and causal relations in order to identify semantic video...... activities, actions, and procedures have been in the focus of the research community over the last years. This research area has strong impact on many real-life applications such as service quality assurance, compliance to the designed procedures in industrial plants, surveillance of people-dense areas (e.......g., thematic parks, critical public infrastructures), crisis management in public service areas (e.g., train stations, airports), security (detection of abnormal behaviors in surveillance videos), semantic characterization, and annotation of video streams in various domains (e.g., broadcast or user...

  10. Parity Bit Replenishment for JPEG 2000-Based Video Streaming

    Directory of Open Access Journals (Sweden)

    François-Olivier Devaux

    2009-01-01

    Full Text Available This paper envisions coding with side information to design a highly scalable video codec. To achieve fine-grained scalability in terms of resolution, quality, and spatial access as well as temporal access to individual frames, the JPEG 2000 coding algorithm has been considered as the reference algorithm to encode INTRA information, and coding with side information has been envisioned to refresh the blocks that change between two consecutive images of a video sequence. One advantage of coding with side information compared to conventional closed-loop hybrid video coding schemes lies in the fact that parity bits are designed to correct stochastic errors and not to encode deterministic prediction errors. This enables the codec to support some desynchronization between the encoder and the decoder, which is particularly helpful to adapt on the fly pre-encoded content to fluctuating network resources and/or user preferences in terms of regions of interest. Regarding the coding scheme itself, to preserve both quality scalability and compliance to the JPEG 2000 wavelet representation, a particular attention has been devoted to the definition of a practical coding framework able to exploit not only the temporal but also spatial correlation among wavelet subbands coefficients, while computing the parity bits on subsets of wavelet bit-planes. Simulations have shown that compared to pure INTRA-based conditional replenishment solutions, the addition of the parity bits option decreases the transmission cost in terms of bandwidth, while preserving access flexibility.

  11. An Evaluation of Streaming Digital Video Resources in On- and Off-Campus Engineering Management Education

    Science.gov (United States)

    Palmer, Stuart

    2007-01-01

    A recent television documentary on the Columbia space shuttle disaster was converted to streaming digital video format for educational use by on- and off-campus students in an engineering management study unit examining issues in professional engineering ethics. An evaluation was conducted to assess the effectiveness of this new resource. Use of…

  12. Wireless live streaming video of laparoscopic surgery: a bandwidth analysis for handheld computers.

    Science.gov (United States)

    Gandsas, Alex; McIntire, Katherine; George, Ivan M; Witzke, Wayne; Hoskins, James D; Park, Adrian

    2002-01-01

    Over the last six years, streaming media has emerged as a powerful tool for delivering multimedia content over networks. Concurrently, wireless technology has evolved, freeing users from desktop boundaries and wired infrastructures. At the University of Kentucky Medical Center, we have integrated these technologies to develop a system that can wirelessly transmit live surgery from the operating room to a handheld computer. This study establishes the feasibility of using our system to view surgeries and describes the effect of bandwidth on image quality. A live laparoscopic ventral hernia repair was transmitted to a single handheld computer using five encoding speeds at a constant frame rate, and the quality of the resulting streaming images was evaluated. No video images were rendered when video data were encoded at 28.8 kilobytes per second (Kbps), the slowest encoding bitrate studied. The highest quality images were rendered at encoding speeds greater than or equal to 150 Kbps. Of note, a 15 second transmission delay was experienced using all four encoding schemes that rendered video images. We believe that the wireless transmission of streaming video to handheld computers has tremendous potential to enhance surgical education. For medical students and residents, the ability to view live surgeries, lectures, courses and seminars on handheld computers means a larger number of learning opportunities. In addition, we envision that wireless enabled devices may be used to telemonitor surgical procedures. However, bandwidth availability and streaming delay are major issues that must be addressed before wireless telementoring becomes a reality.

  13. The Davideon Project: Capitalizing the Possibilities of Streaming Video as Flexible Learning Objects for the Humanities

    Science.gov (United States)

    Rosendaal, Andre; Oomen, Johan

    2005-01-01

    Streaming video is a potentially revolutionary tool in humanities courses. The Davideon project, a large-scale effort conducted by the University of Groningen in conjunction with the University of Amsterdam, Windesheim University, and the Netherlands Institute for Sound and Vision, focused on integrating audiovisual materials into pedagogically…

  14. The EduPop: Improving Streaming Video for an Electronic Community.

    Science.gov (United States)

    Daugherty, Hubert; Cohn, Julie; Gorry, G. Anthony

    2003-01-01

    Provides examples of the need for enhanced streaming video in the greater Houston area, discussing how the EduPop router architecture meets this need by acting as a bridge for academic and commercial entities in the area. Catalogues the technological, organizational, and political challenges faced in implementing this architecture, offering a…

  15. Adaptive end-to-end optimization of mobile video streaming using QoS negotiation

    NARCIS (Netherlands)

    Taal, Jacco R.; Langendoen, Koen; van der Schaaf, Arjen; van Dijk, H.W.; Lagendijk, R. (Inald) L.

    Video streaming over wireless links is a non-trivial problem due to the large and frequent changes in the quality of the underlying radio channel combined with latency constraints. We believe that every layer in a mobile system must be prepared to adapt its behavior to its environment. Thus layers

  16. Capabilities of Raspberry Pi 2 for Big Data and Video Streaming Applications in Data Centres

    NARCIS (Netherlands)

    Schot, Nick J.; Velthuis, Paul J.E.; Postema, Björn Frits; Remke, Anne Katharina Ingrid; Remke, A.K.I.; Haverkort, Boudewijn R.H.M.; Haverkort, B.R.H.M.

    Many new data centres have been built in recent years in order to keep up with the rising demand for server capacity. These data centres require a lot of electrical energy and cooling. Big data and video streaming are two heavily used applications in data centres. This paper experimentally

  17. Using Text Mining to Uncover Students' Technology-Related Problems in Live Video Streaming

    Science.gov (United States)

    Abdous, M'hammed; He, Wu

    2011-01-01

    Because of their capacity to sift through large amounts of data, text mining and data mining are enabling higher education institutions to reveal valuable patterns in students' learning behaviours without having to resort to traditional survey methods. In an effort to uncover live video streaming (LVS) students' technology related-problems and to…

  18. Intelligent Packet Shaper to Avoid Network Congestion for Improved Streaming Video Quality at Clients

    DEFF Research Database (Denmark)

    Kaul, Manohar; Khosla, Rajiv; Mitsukura, Y

    2003-01-01

    of this intelligent traffic-shaping algorithm on the underlying network real time packet traffic and the eradication of unwanted abruption in the streaming video qualiy. This paper concluded from the end results of the simulation that neural networks are a very superior means of modeling real-time traffic......This paper proposes a traffic shaping algorithm based on neural networks, which adapts to a network over which streaming video is being transmitted. The purpose of this intelligent shaper is to eradicate all traffic congestion and improve the end-user's video quality. It possesses the capability...... to predict, to a very high level of accuracy, a state of congestion based upon the training data collected about the network behaviour. Initially, the current traffic shaping technologies are discussed and later a simulation in a controlled environment is illustrated to exhibit the effects...

  19. Distributed video streaming using multiple description coding and unequal error protection.

    Science.gov (United States)

    Kim, Joohee; Mersereau, Russell M; Altunbasak, Yucel

    2005-07-01

    This paper presents a distributed video streaming framework using unbalanced multiple description coding (MDC) and unequal error protection. In the proposed video streaming framework, two senders simultaneously stream complementary descriptions to a single receiver over different paths. To minimize the overall distortion and exploit the benefits of multipath transport when the characteristics of each path are different, an unbalanced MDC method for wavelet-based coders combined with a TCP-friendly rate allocation algorithm is proposed. The proposed rate allocation algorithm adjusts the transmission rates and the channel coding rates for all senders in a coordinated fashion to minimize the overall distortion. Simulation results show that the proposed unbalanced MDC combined with our rate allocation algorithm achieves about 1-6 dB higher peal signal-to-noise ratio compared to conventional balanced MDC when the available bandwidths along the two paths are different under time-varying network conditions.

  20. Experiments and video analysis in classical mechanics

    CERN Document Server

    de Jesus, Vitor L B

    2017-01-01

    This book is an experimental physics textbook on classical mechanics focusing on the development of experimental skills by means of discussion of different aspects of the experimental setup and the assessment of common issues such as accuracy and graphical representation. The most important topics of an experimental physics course on mechanics are covered and the main concepts are explored in detail. Each chapter didactically connects the experiment and the theoretical models available to explain it. Real data from the proposed experiments are presented and a clear discussion over the theoretical models is given. Special attention is also dedicated to the experimental uncertainty of measurements and graphical representation of the results. In many of the experiments, the application of video analysis is proposed and compared with traditional methods.

  1. Use of streamed internet video for cytology training and education: www.PathLab.org.

    Science.gov (United States)

    Poller, David; Ljung, Britt-Marie; Gonda, Peter

    2009-05-01

    An Internet-based method is described for submission of video clips to a website editor to be reviewed, edited, and then uploaded onto a video server, with a hypertext link to a website. The information on the webpages is searchable via the website sitemap on Internet search engines. A survey of video users who accessed a single 59-minute FNA cytology training cytology video via the website showed a mean score for usefulness for specialists/consultants of 3.75, range 1-5, n = 16, usefulness for trainees mean score was 4.4, range 3-5, n = 12, with a mean score for visual and sound quality of 3.9, range 2-5, n = 16. Fifteen out of 17 respondents thought that posting video training material on the Internet was a good idea, and 9 of 17 respondents would also consider submitting training videos to a similar website. This brief exercise has shown that there is value in posting educational or training video content on the Internet and that the use of streamed video accessed via the Internet will be of increasing importance. (c) 2009 Wiley-Liss, Inc.

  2. Game-theoretic pricing for video streaming in mobile networks.

    Science.gov (United States)

    Lin, W Sabrina; Liu, K J Ray

    2012-05-01

    Mobile phones are among the most popular consumer devices, and the recent developments of 3G networks and smart phones enable users to watch video programs by subscribing data plans from service providers. Due to the ubiquity of mobile phones and phone-to-phone communication technologies, data-plan subscribers can redistribute the video content to nonsubscribers. Such a redistribution mechanism is a potential competitor for the mobile service provider and is very difficult to trace given users' high mobility. The service provider has to set a reasonable price for the data plan to prevent such unauthorized redistribution behavior to protect or maximize his/her own profit. In this paper, we analyze the optimal price setting for the service provider by investigating the equilibrium between the subscribers and the secondary buyers in the content-redistribution network. We model the behavior between the subscribers and the secondary buyers as a noncooperative game and find the optimal price and quantity for both groups of users. Based on the behavior of users in the redistribution network, we investigate the evolutionarily stable ratio of mobile users who decide to subscribe to the data plan. Such an analysis can help the service provider preserve his/her profit under the threat of the redistribution networks and can improve the quality of service for end users.

  3. Downlink Video Streaming for Users Non-Equidistant from Base Station

    Directory of Open Access Journals (Sweden)

    S. Pejoski

    2012-06-01

    Full Text Available We consider multiuser video transmission for users that are non-equidistantly positioned from base station. We propose a greedy algorithm for video streaming in a wireless system with capacity achieving channel coding, that implements the cross-layer principle by partially separating the physical and the application layer. In such a system the parameters at the physical layer are dependent on the packet length and the conditions in the wireless channel and the parameters at the application layer are dependent on the reduction of the expected distortion assuming no packet errors in the system. We also address the fairness in the multiuser video system with non-equidistantly positioned users. Our fairness algorithm is based on modified opportunistic round robin scheduling. We evaluate the performance of the proposed algorithms by simulating the transmission of H.264/AVC video signals in a TDMA wireless system.

  4. Adaptive Video Streaming Using Bandwidth Estimation for 3.5G Mobile Network

    Science.gov (United States)

    Nam, Hyeong-Min; Park, Chun-Su; Jung, Seung-Won; Ko, Sung-Jea

    Currently deployed mobile networks including High Speed Downlink Packet Access (HSDPA) offer only best-effort Quality of Service (QoS). In wireless best effort networks, the bandwidth variation is a critical problem, especially, for mobile devices with small buffers. This is because the bandwidth variation leads to packet losses caused by buffer overflow as well as picture freezing due to high transmission delay or buffer underflow. In this paper, in order to provide seamless video streaming over HSDPA, we propose an efficient real-time video streaming method that consists of the available bandwidth (AB) estimation for the HSDPA network and the transmission rate control to prevent buffer overflows/underflows. In the proposed method, the client estimates the AB and the estimated AB is fed back to the server through real-time transport control protocol (RTCP) packets. Then, the server adaptively adjusts the transmission rate according to the estimated AB and the buffer state obtained from the RTCP feedback information. Experimental results show that the proposed method achieves seamless video streaming over the HSDPA network providing higher video quality and lower transmission delay.

  5. Reducing video-quality fluctuations for streaming scalable video using unequal error protection, retransmission, and interleaving.

    Science.gov (United States)

    Gan, Tong; Gan, Lu; Ma, Kai-Kuang

    2006-04-01

    Forward error correction based multiple description (MD-FEC) transcoding for transmitting embedded bitstream over the packet erasure networks has been extensively studied in the past. In the existing work, a single embedded source bitstream, e.g., the bitstream of a group of pictures (GOP) encoded using three-dimensional set partitioning in hierarchical trees is optimally protected unequal error protection (UEP) in the rate-distortion sense. However, most of the previous work on transmitting embedded video using MD-FEC assumed that one GOP is transmitted only once, and did not consider the chance of retransmission. This may lead to noticeable video quality variations due to varying channel conditions. In this paper, a novel window-based packetization scheme is proposed, which combats bursty packet loss by combining the following three techniques: UEP, retransmission, and GOP-level interleaving. In particular, two retransmission mechanisms, namely segment-wise retransmission and byte-wise retransmission, are proposed based on different types of receiver feedback. Moreover, two levels of rate allocations are introduced: intra-GOP rate allocation minimizes the distortion of individual GOP; while inter-GOP rate allocation intends to reduce video quality fluctuations by adaptively allocating bandwidth according to video signal characteristics and client buffer status. In this way, more consistent video quality can be achieved under various packet loss probabilities, as demonstrated by our experimental results.

  6. MAC-Layer Active Dropping for Real-Time Video Streaming in 4G Access Networks

    KAUST Repository

    She, James

    2010-12-01

    This paper introduces a MAC-layer active dropping scheme to achieve effective resource utilization, which can satisfy the application-layer delay for real-time video streaming in time division multiple access based 4G broadband wireless access networks. When a video frame is not likely to be reconstructed within the application-layer delay bound at a receiver for the minimum decoding requirement, the MAC-layer protocol data units of such video frame will be proactively dropped before the transmission. An analytical model is developed to evaluate how confident a video frame can be delivered within its application-layer delay bound by jointly considering the effects of time-varying wireless channel, minimum decoding requirement of each video frame, data retransmission, and playback buffer. Extensive simulations with video traces are conducted to prove the effectiveness of the proposed scheme. When compared to conventional cross-layer schemes using prioritized-transmission/retransmission, the proposed scheme is practically implementable for more effective resource utilization, avoiding delay propagation, and achieving better video qualities under certain conditions.

  7. Intelligent Stale-Frame Discards for Real-Time Video Streaming over Wireless Ad Hoc Networks

    Directory of Open Access Journals (Sweden)

    Sheu Tsang-Ling

    2009-01-01

    Full Text Available Abstract This paper presents intelligent early packet discards (I-EPD for real-time video streaming over a multihop wireless ad hoc network. In a multihop wireless ad hoc network, the quality of transferring real-time video streams could be seriously degraded, since every intermediate node (IN functionally like relay device does not possess large buffer and sufficient bandwidth. Even worse, a selected relay node could leave or power off unexpectedly, which breaks the route to destination. Thus, a stale video frame is useless even if it can reach destination after network traffic becomes smooth or failed route is reconfigured. In the proposed I-EPD, an IN can intelligently determine whether a buffered video packet should be early discarded. For the purpose of validation, we implement the I-EPD on Linux-based embedded systems. Via the comparisons of performance metrics (packet/frame discards ratios, PSNR, etc., we demonstrate that video quality over a wireless ad hoc network can be substantially improved and unnecessary bandwidth wastage is greatly reduced.

  8. Intelligent Stale-Frame Discards for Real-Time Video Streaming over Wireless Ad Hoc Networks

    Directory of Open Access Journals (Sweden)

    Yung-Shih Chi

    2009-01-01

    Full Text Available This paper presents intelligent early packet discards (I-EPD for real-time video streaming over a multihop wireless ad hoc network. In a multihop wireless ad hoc network, the quality of transferring real-time video streams could be seriously degraded, since every intermediate node (IN functionally like relay device does not possess large buffer and sufficient bandwidth. Even worse, a selected relay node could leave or power off unexpectedly, which breaks the route to destination. Thus, a stale video frame is useless even if it can reach destination after network traffic becomes smooth or failed route is reconfigured. In the proposed I-EPD, an IN can intelligently determine whether a buffered video packet should be early discarded. For the purpose of validation, we implement the I-EPD on Linux-based embedded systems. Via the comparisons of performance metrics (packet/frame discards ratios, PSNR, etc., we demonstrate that video quality over a wireless ad hoc network can be substantially improved and unnecessary bandwidth wastage is greatly reduced.

  9. Performance analysis of medical video streaming over mobile WiMAX.

    Science.gov (United States)

    Alinejad, Ali; Philip, N; Istepanian, R H

    2010-01-01

    Wireless medical ultrasound streaming is considered one of the emerging application within the broadband mobile healthcare domain. These applications are considered as bandwidth demanding services that required high data rates with acceptable diagnostic quality of the transmitted medical images. In this paper, we present the performance analysis of a medical ultrasound video streaming acquired via special robotic ultrasonography system over emulated WiMAX wireless network. The experimental set-up of this application is described together with the performance of the relevant medical quality of service (m-QoS) metrics.

  10. Meteoroid orbits from video meteors. The case of the Geminid stream

    Science.gov (United States)

    Hajduková, Mária, Jr.; Koten, Pavel; Kornoš, Leonard; Tóth, Juraj

    2017-09-01

    We use the Slovak and Czech video meteor observations, as well as video meteoroid orbits collected in the CAMS, SonotaCo, EDMOND and DMS catalogues, for an analysis of the distribution of meteoroid orbits within the stream of the Geminids and of the dispersion of their radiants. We concentrate on the influence of the measurement errors on the precision of the orbits obtained from the video networks that are based on various meteor-detection software packages and various meteor orbital element softwares. The Geminids radiant dispersion obtained from the large video catalogues reaches the dispersion of the radio observed Geminids, whereby the diffused marginal regions are affected mostly by meteoroids with extreme values (small or large) of the semi-major axes. Meteoroids of shorter semi-major axes concentrate at the eastern side of the radiant area and those of longer semi-major axes at the western part. The observed orbital dispersions in the Geminid stream described by the median absolute deviation range from 0.029 to 0.042 AU-1 for the video catalogues. The distribution of the semi-major axes of video meteors in all the databases, except for the Ondřejov (Czech) data, seem to be systematically biased in comparison with the photographic and radio meteors. The determined velocities of the video data are underestimated, probably as a consequence of the methods used for the positional and velocity measurements. The largest shift is observed in the EDMOND and SonotaCo catalogues. Except for the measurement errors which influence the analyses and their interpretations, we also point out the problem of the uncertainties of the numerical integration procedures that influence the simulations' results. Several experimental integrations of the Geminids parent asteroid, which we performed from the present to the past and then back to the year 2015, showed that a complete reproduction, including also the mean anomaly, is only possible for a time span of about 2700 years.

  11. Task-oriented quality assessment and adaptation in real-time mission critical video streaming applications

    Science.gov (United States)

    Nightingale, James; Wang, Qi; Grecos, Christos

    2015-02-01

    In recent years video traffic has become the dominant application on the Internet with global year-on-year increases in video-oriented consumer services. Driven by improved bandwidth in both mobile and fixed networks, steadily reducing hardware costs and the development of new technologies, many existing and new classes of commercial and industrial video applications are now being upgraded or emerging. Some of the use cases for these applications include areas such as public and private security monitoring for loss prevention or intruder detection, industrial process monitoring and critical infrastructure monitoring. The use of video is becoming commonplace in defence, security, commercial, industrial, educational and health contexts. Towards optimal performances, the design or optimisation in each of these applications should be context aware and task oriented with the characteristics of the video stream (frame rate, spatial resolution, bandwidth etc.) chosen to match the use case requirements. For example, in the security domain, a task-oriented consideration may be that higher resolution video would be required to identify an intruder than to simply detect his presence. Whilst in the same case, contextual factors such as the requirement to transmit over a resource-limited wireless link, may impose constraints on the selection of optimum task-oriented parameters. This paper presents a novel, conceptually simple and easily implemented method of assessing video quality relative to its suitability for a particular task and dynamically adapting videos streams during transmission to ensure that the task can be successfully completed. Firstly we defined two principle classes of tasks: recognition tasks and event detection tasks. These task classes are further subdivided into a set of task-related profiles, each of which is associated with a set of taskoriented attributes (minimum spatial resolution, minimum frame rate etc.). For example, in the detection class

  12. Video to Go: the effects of mobility on streaming media in a CDMA2000 1xEV-DO network

    Science.gov (United States)

    Sessini, Phillipa; Leventer, Matei; Mahanti, Anirban

    2007-01-01

    This paper experimentally examines the performance of streaming media applications over a CDMA2000 1xEV-DO network. The performance of streaming in a cellular network is tested across three different levels of mobility, two applications, and the two transport layer protocols, TCP and UDP. Findings of this study are that streaming applications are impacted more by sources of interference such as high-rise buildings than by increased velocity. Also, when the mobile client is stationary, high data rates and high video quality are consistently achieved. We also find that for the streaming applications considered, UDP streams outperform TCP streams, consistently achieving higher bandwidth.

  13. Enhancing the Dialogue in Simultaneous Class-Based and Live Video-Streamed Teaching

    DEFF Research Database (Denmark)

    Jelsbak, Vibe Alopaeus; Ørngreen, Rikke; Thorsen, Jonas

    2015-01-01

    from home via the Internet. In live video-streamed teaching classes teachers tend to choose one-way communication instead of dialogue. We know from our early findings that technology issues are one of the main reasons for this, since the same teachers use dialogue and discussions in traditional......The bachelor programme in biomedical laboratory analysis at VIA University College in Aarhus has established a blended class concept which combines traditional and live broadcast teaching. 1-2 days a week students have the choice either to attend teaching sessions in the traditional way or to work...... teaching. This paper describes a work-in-progress project focused on developing possibilities for a more dialogue-based approach to live video-streamed teaching. We present our new setup and argue for educational designs which this is believed to support, and we outline the research design for collecting...

  14. Enhancing the Dialogue in Simultaneous Class-Based and Live Video-Streamed Teaching

    DEFF Research Database (Denmark)

    Jelsbak, Vibe Alopaeus; Bendsen, Thomas; Thorsen, Jonas

    2015-01-01

    or to work from home via the Internet. In live video-streamed teaching classes teachers tend to choose one-way communication instead of dialogue. We know from our early findings that technology issues are one of the main reasons for this, since the same teachers use dialogue and discussions in traditional......Abstract: The bachelor programme in biomedical laboratory analysis at VIA University College in Aarhus has established a blended class concept which combines traditional and live broadcast teaching. 1-2 days a week students have the choice either to attend teaching sessions in the traditional way...... teaching. This paper describes a work-in-progress project focused on developing possibilities for a more dialogue-based approach to live video-streamed teaching. We present our new setup and argue for educational de- signs which this is believed to support, and we outline the research design for collecting...

  15. Optimisation Issues of High Throughput Medical Data and Video Streaming Traffic in 3G Wireless Environments.

    Science.gov (United States)

    Istepanian, R S H; Philip, N

    2005-01-01

    In this paper we describe some of the optimisation issues relevant to the requirements of high throughput of medical data and video streaming traffic in 3G wireless environments. In particular we present a challenging 3G mobile health care application that requires a demanding 3G medical data throughput. We also describe the 3G QoS requirement of mObile Tele-Echography ultra-Light rObot system (OTELO that is designed to provide seamless 3G connectivity for real-time ultrasound medical video streams and diagnosis from a remote site (robotic and patient station) manipulated by an expert side (specialists) that is controlling the robotic scanning operation and presenting a real-time feedback diagnosis using 3G wireless communication links.

  16. The effects of camera jitter for background subtraction algorithms on fused infrared-visible video streams

    Science.gov (United States)

    Becker, Stefan; Scherer-Negenborn, Norbert; Thakkar, Pooja; Hübner, Wolfgang; Arens, Michael

    2016-10-01

    This paper is a continuation of the work of Becker et al.1 In their work, they analyzed the robustness of various background subtraction algorithms on fused video streams originating from visible and infrared cameras. In order to cover a broader range of background subtraction applications, we show the effects of fusing infrared-visible video streams from vibrating cameras on a large set of background subtraction algorithms. The effectiveness is quantitatively analyzed on recorded data of a typical outdoor sequence with a fine-grained and accurate annotation of the images. Thereby, we identify approaches which can benefit from fused sensor signals with camera jitter. Finally conclusions on what fusion strategies should be preferred under such conditions are given.

  17. On Cross-Layer Design for Streaming Video Delivery in Multiuser Wireless Environments

    Directory of Open Access Journals (Sweden)

    Kellerer Wolfgang

    2006-01-01

    Full Text Available We exploit the interlayer coupling of a cross-layer design concept for streaming video delivery in a multiuser wireless environment. We propose a cross-layer optimization between application layer, data link layer, and physical layer. Our aim is to optimize the end-to-end quality of the wireless streaming video application as well as efficiently utilizing the wireless resources. A possible architecture for achieving this goal is proposed and formulated. This architecture consists of the process of parameter abstraction, a cross-layer optimizer, and the process of decision distribution. In addition, numerical results obtained with different operating modes are provided. The results demonstrate the potential of this proposed joint optimization.

  18. A high performance FDDI NIU for streaming voice, video, and data

    Science.gov (United States)

    Bergman, L. A.; Hartmayer, R.; Wu, W.; Cassell, P.; Edgar, G.; Lambert, J.; Mancini, R.; Jeng, J.; Pardo, C.; Halloran, F.

    1991-01-01

    A 100-Mbit/s FDDI network interface unit (NIU) is described that supports real-time data, voice and video. Its high-speed interrupt-driven hardware architecture efficiently manages stream and packet data transfers to the FDDI network. Other enhancements include modular single-mode laser-dioce fiber optic links to maximize node spacing, optic bypass switches for increased fault tolerance, and a hardware performance monitor to gather real-time network diagnostics.

  19. Rate-Distortion Optimized Frame Dropping for Multiuser Streaming and Conversational Videos

    OpenAIRE

    Eckehard Steinbach; Jacob Chakareski; Wei Tu

    2008-01-01

    We consider rate-distortion optimized strategies for dropping frames from multiple conversational and streaming videos sharing limited network node resources. The dropping strategies are based on side information that is extracted during encoding and is sent along the regular bitstream. The additional transmission overhead and the computational complexity of the proposed frame dropping schemes are analyzed. Our experimental results show that a significant improvement in end-to-end performance...

  20. Control and Innovation on Digital Platforms : the case of Netflix and streaming of video content

    OpenAIRE

    Vigeland, Eirik

    2012-01-01

    In this thesis I investigate innovation processes on innovation platforms, and look at the role played by content release for innovation in digital distribution of home entertainment. I argue that innovation platforms rely on several aspects of innovation in order to succeed, and this thesis is concerned with one of these, namely release of digital entertainment content. I use the American video streaming service Netflix as a case and example of such an innovation platform. By using techno...

  1. Cross-layer Control for Adaptive Video Streaming over Wireless Access Networks

    OpenAIRE

    Abdallah AbouSheaisha, Abdallah Sabry

    2016-01-01

    Over the last decade, the wide deployment of wireless access technologies (e.g. WiFi, 3G, and LTE) and the remarkable growth in the volume of streaming video content have significantly altered the telecommunications field. These developments introduce new challenges to the research community including the need to develop new solutions (e.g. traffic models and transport protocols) to address changing traffic patterns and the characteristics of wireless links and the need for new evaluation me...

  2. The Impact of Video Streaming on Mathematics Performance

    Science.gov (United States)

    Boster, Franklin J.; Meyer, Gary S.; Roberto, Anthony J.; Lindsey, Lisa; Smith, Rachel; Inge, Carol; Strom, Renee E.

    2007-01-01

    Relying on a series of four experiments, F. J. Boster, G. S. Meyer, A. J. Roberto, C. Inge, and R. E. Strom (2006) demonstrated that students exposed to videostreaming exhibited more improvement in examination performance than control students. In extension, this study tests the effect of using videostreaming with a very different topic…

  3. Cross-Layer Design of Source Rate Control and Congestion Control for Wireless Video Streaming

    Directory of Open Access Journals (Sweden)

    Peng Zhu

    2007-01-01

    Full Text Available Cross-layer design has been used in streaming video over the wireless channels to optimize the overall system performance. In this paper, we extend our previous work on joint design of source rate control and congestion control for video streaming over the wired channel, and propose a cross-layer design approach for wireless video streaming. First, we extend the QoS-aware congestion control mechanism (TFRCC proposed in our previous work to the wireless scenario, and provide a detailed discussion about how to enhance the overall performance in terms of rate smoothness and responsiveness of the transport protocol. Then, we extend our previous joint design work to the wireless scenario, and a thorough performance evaluation is conducted to investigate its performance. Simulation results show that by cross-layer design of source rate control at application layer and congestion control at transport layer, and by taking advantage of the MAC layer information, our approach can avoid the throughput degradation caused by wireless link error, and better support the QoS requirements of the application. Thus, the playback quality is significantly improved, while good performance of the transport protocol is still preserved.

  4. A new error resilience method for FGS video enhancement bit-stream

    Science.gov (United States)

    Ma, Ran; Zhang, Zhao-yang; An, Ping

    2006-05-01

    Video streaming over the Internet usually encounters with bandwidth variations and packet losses, which impacted badly on the reconstructed video quality. Fine Granularity Scalability (FGS) can well provide bit-rate adaptability to different bandwidth conditions over the Internet, due to its fine granular and error resilience. However, the effective solution of packet losses is Multiple Description Coding (MDC), but a great deal of redundancy information is brought up. For an FGS video bit-stream, the base layer is usually very small and of high importance, error-free transmission could be achieved through classical error resilience technique. As a result, the overall streaming quality is mostly dependent on the enhancement layer. Moreover, it is worthy of note that the different bit-planes are of different importance, which are suitable to unequal protection (UEP) strategy. So, a new joint MDC and UEP method is proposed to protect the enhancement layer in this paper. In the proposed method, the MDC encoder/decoder is embedded into the normal enhancement layer encoder/decoder. By considering of the unequal protection of bit-plane and the redundancy of MDC, the two most significant bit-planes adopt the MDC-based strategy. While, the remaining bit-planes only encoded by normal enhancement layer coding system. Experimental results are demonstrated to testify the efficiency of our proposed method.

  5. Comprehensive Protection of Data-Partitioned Video for Broadband Wireless IPTV Streaming

    Directory of Open Access Journals (Sweden)

    Laith Al-Jobouri

    2012-01-01

    Full Text Available This paper examines the threat to video streaming from slow and fast fading, traffic congestion, and channel packet drops. The proposed response is a combination of: rateless channel coding, which is adaptively applied; data-partitioned source coding to exploit prioritized packetization; and duplicate slice provision, which is the focus of the evaluation in this paper. The paper also considers the distribution of intra-refresh macroblocks as a means of avoiding sudden data rate increases. When error bursts occur, this paper shows that duplicate slices are certainly necessary but this provision is more effective for medium quality video than it is for high quality video. The percentage of intra-refresh macroblocks can be low and still reduce the impact of temporal error propagation.

  6. Energy-Efficient Bandwidth Allocation for Multiuser Scalable Video Streaming over WLAN

    Directory of Open Access Journals (Sweden)

    Lafruit Gauthier

    2008-01-01

    Full Text Available Abstract We consider the problem of packet scheduling for the transmission of multiple video streams over a wireless local area network (WLAN. A cross-layer optimization framework is proposed to minimize the wireless transceiver energy consumption while meeting the user required visual quality constraints. The framework relies on the IEEE 802.11 standard and on the embedded bitstream structure of the scalable video coding scheme. It integrates an application-level video quality metric as QoS constraint (instead of a communication layer quality metric with energy consumption optimization through link layer scaling and sleeping. Both energy minimization and min-max energy optimization strategies are discussed. Simulation results demonstrate significant energy gains compared to the state-of-the-art approaches.

  7. Energy-Efficient Bandwidth Allocation for Multiuser Scalable Video Streaming over WLAN

    Directory of Open Access Journals (Sweden)

    Xin Ji

    2008-01-01

    Full Text Available We consider the problem of packet scheduling for the transmission of multiple video streams over a wireless local area network (WLAN. A cross-layer optimization framework is proposed to minimize the wireless transceiver energy consumption while meeting the user required visual quality constraints. The framework relies on the IEEE 802.11 standard and on the embedded bitstream structure of the scalable video coding scheme. It integrates an application-level video quality metric as QoS constraint (instead of a communication layer quality metric with energy consumption optimization through link layer scaling and sleeping. Both energy minimization and min-max energy optimization strategies are discussed. Simulation results demonstrate significant energy gains compared to the state-of-the-art approaches.

  8. Mediating Tourist Experiences. Access to Places via Shared Videos

    DEFF Research Database (Denmark)

    Tussyadiah, Iis; Fesenmaier, D.R.

    2009-01-01

    The emergence of new media using multimedia features has generated a new set of mediators for tourists' experiences. This study examines two hypotheses regarding the roles that online travel videos play as mediators of tourist experiences. The results confirm that online shared videos can provide...... mental pleasure to viewers by stimulating fantasies and daydreams, as well as bringing back past travel memories. In addition, the videos act as a narrative transportation, providing access to foreign landscapes and socioscapes....

  9. Lightweight Object Tracking in Compressed Video Streams Demonstrated in Region-of-Interest Coding

    Directory of Open Access Journals (Sweden)

    Rik Van de Walle

    2007-01-01

    Full Text Available Video scalability is a recent video coding technology that allows content providers to offer multiple quality versions from a single encoded video file in order to target different kinds of end-user devices and networks. One form of scalability utilizes the region-of-interest concept, that is, the possibility to mark objects or zones within the video as more important than the surrounding area. The scalable video coder ensures that these regions-of-interest are received by an end-user device before the surrounding area and preferably in higher quality. In this paper, novel algorithms are presented making it possible to automatically track the marked objects in the regions of interest. Our methods detect the overall motion of a designated object by retrieving the motion vectors calculated during the motion estimation step of the video encoder. Using this knowledge, the region-of-interest is translated, thus following the objects within. Furthermore, the proposed algorithms allow adequate resizing of the region-of-interest. By using the available information from the video encoder, object tracking can be done in the compressed domain and is suitable for real-time and streaming applications. A time-complexity analysis is given for the algorithms proving the low complexity thereof and the usability for real-time applications. The proposed object tracking methods are generic and can be applied to any codec that calculates the motion vector field. In this paper, the algorithms are implemented within MPEG-4 fine-granularity scalability codec. Different tests on different video sequences are performed to evaluate the accuracy of the methods. Our novel algorithms achieve a precision up to 96.4%.

  10. Lightweight Object Tracking in Compressed Video Streams Demonstrated in Region-of-Interest Coding

    Directory of Open Access Journals (Sweden)

    Lerouge Sam

    2007-01-01

    Full Text Available Video scalability is a recent video coding technology that allows content providers to offer multiple quality versions from a single encoded video file in order to target different kinds of end-user devices and networks. One form of scalability utilizes the region-of-interest concept, that is, the possibility to mark objects or zones within the video as more important than the surrounding area. The scalable video coder ensures that these regions-of-interest are received by an end-user device before the surrounding area and preferably in higher quality. In this paper, novel algorithms are presented making it possible to automatically track the marked objects in the regions of interest. Our methods detect the overall motion of a designated object by retrieving the motion vectors calculated during the motion estimation step of the video encoder. Using this knowledge, the region-of-interest is translated, thus following the objects within. Furthermore, the proposed algorithms allow adequate resizing of the region-of-interest. By using the available information from the video encoder, object tracking can be done in the compressed domain and is suitable for real-time and streaming applications. A time-complexity analysis is given for the algorithms proving the low complexity thereof and the usability for real-time applications. The proposed object tracking methods are generic and can be applied to any codec that calculates the motion vector field. In this paper, the algorithms are implemented within MPEG-4 fine-granularity scalability codec. Different tests on different video sequences are performed to evaluate the accuracy of the methods. Our novel algorithms achieve a precision up to 96.4 .

  11. Multimedia applications in nursing curriculum: the process of producing streaming videos for medication administration skills.

    Science.gov (United States)

    Sowan, Azizeh K

    2014-07-01

    Streaming videos (SVs) are commonly used multimedia applications in clinical health education. However, there are several negative aspects related to the production and delivery of SVs. Only a few published studies have included sufficient descriptions of the videos and the production process and design innovations. This paper describes the production of innovative SVs for medication administration skills for undergraduate nursing students at a public university in Jordan and focuses on the ethical and cultural issues in producing this type of learning resource. The curriculum development committee approved the modification of educational techniques for medication administration procedures to include SVs within an interactive web-based learning environment. The production process of the videos adhered to established principles for "protecting patients' rights when filming and recording" and included: preproduction, production and postproduction phases. Medication administration skills were videotaped in a skills laboratory where they are usually taught to students and also in a hospital setting with real patients. The lab videos included critical points and Do's and Don'ts and the hospital videos fostered real-world practices. The range of time of the videos was reasonable to eliminate technical difficulty in access. Eight SVs were produced that covered different types of the medication administration skills. The production of SVs required the collaborative efforts of experts in IT, multimedia, nursing and informatics educators, and nursing care providers. Results showed that the videos were well-perceived by students, and the instructors who taught the course. The process of producing the videos in this project can be used as a valuable framework for schools considering utilizing multimedia applications in teaching. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  12. Quality Analysis of Massive High-Definition Video Streaming in Two-Tiered Embedded Camera-Sensing Systems

    OpenAIRE

    Joongheon Kim; Eun-Seok Ryu

    2014-01-01

    This paper presents the quality analysis results of high-definition video streaming in two-tiered camera sensor network applications. In the camera-sensing system, multiple cameras sense visual scenes in their target fields and transmit the video streams via IEEE 802.15.3c multigigabit wireless links. However, the wireless transmission introduces interferences to the other links. This paper analyzes the capacity degradation due to the interference impacts from the camera-sensing nodes to the ...

  13. A First Look at Quality of Mobile Live Streaming Experience: the Case of Periscope

    OpenAIRE

    Siekkinen, Matti; Masala, Enrico; Kämäräinen, Teemu

    2016-01-01

    Live multimedia streaming from mobile devices is rapidly gaining popularity but little is known about the QoE they provide. In this paper, we examine the Periscope service. We first crawl the service in order to understand its usage patterns. Then, we study the protocols used, the typical quality of experience indicators, such as playback smoothness and latency, video quality, and the energy consumption of the Android application.

  14. Display device-adapted video quality-of-experience assessment

    Science.gov (United States)

    Rehman, Abdul; Zeng, Kai; Wang, Zhou

    2015-03-01

    Today's viewers consume video content from a variety of connected devices, including smart phones, tablets, notebooks, TVs, and PCs. This imposes significant challenges for managing video traffic efficiently to ensure an acceptable quality-of-experience (QoE) for the end users as the perceptual quality of video content strongly depends on the properties of the display device and the viewing conditions. State-of-the-art full-reference objective video quality assessment algorithms do not take into account the combined impact of display device properties, viewing conditions, and video resolution while performing video quality assessment. We performed a subjective study in order to understand the impact of aforementioned factors on perceptual video QoE. We also propose a full reference video QoE measure, named SSIMplus, that provides real-time prediction of the perceptual quality of a video based on human visual system behaviors, video content characteristics (such as spatial and temporal complexity, and video resolution), display device properties (such as screen size, resolution, and brightness), and viewing conditions (such as viewing distance and angle). Experimental results have shown that the proposed algorithm outperforms state-of-the-art video quality measures in terms of accuracy and speed.

  15. VIDEO '78: International Experience and Models.

    Science.gov (United States)

    Prix Jeunesse Foundation, Munich (Germany).

    The use of video technology as an alternative form of communications media for artists, teachers, students, and community groups in the United States, Europe, and Third World nations is described. Specific examples of video use in the various countries are outlined and individual characteristics of program organization, production, and…

  16. The Aesthetics of the Ambient Video Experience

    Directory of Open Access Journals (Sweden)

    Jim Bizzocchi

    2008-01-01

    Full Text Available Ambient Video is an emergent cultural phenomenon, with roots that go deeply into the history of experimental film and video art. Ambient Video, like Brian Eno's ambient music, is video that "must be as easy to ignore as notice" [9]. This minimalist description conceals the formidable aesthetic challenge that faces this new form. Ambient video art works will hang on the walls of our living rooms, corporate offices, and public spaces. They will play in the background of our lives, living video paintings framed by the new generation of elegant, high-resolution flat-panel display units. However, they cannot command attention like a film or television show. They will patiently play in the background of our lives, yet they must always be ready to justify our attention in any given moment. In this capacity, ambient video works need to be equally proficient at rewarding a fleeting glance, a more direct look, or a longer contemplative gaze. This paper connects a series of threads that collectively illuminate the aesthetics of this emergent form: its history as a popular culture phenomenon, its more substantive artistic roots in avant-garde cinema and video art, its relationship to new technologies, the analysis of the viewer's conditions of reception, and the work of current artists who practice within this form.

  17. Wireless live streaming video of surgical operations: an evaluation of communication quality.

    Science.gov (United States)

    Schneider, Armin; Wilhelm, Dirk; Doll, Dietrich; Rauschenbach, Uwe; Finkenzeller, Michael; Wirnhier, Helga; Illgner, Klaus; Feussner, Hubertus

    2007-01-01

    We evaluated a mobile video system for surgical teleconsultation. A video streaming server in the operating room transmitted video and audio to a hand-held computer (personal digital assistant [PDA]) over a wireless local area network. Two groups of 20 surgeons (each with 12 qualified surgeons and eight surgeons between the 2nd and the 4th year of training) participated in the tests. For voice transmission, correct understanding of numbers was achieved in 100% of the cases (n = 1000) and 98% of medical terms (n = 400). The quality of the video displayed on the PDA was assessed by the recognition of different operating room scenarios. Only 62% (SD 17) of the structures were identified clearly on the hand-held device (n = 400). The accuracy improved to 78% (SD 15) (n = 400) if the same scenario was observed on a larger (50 cm) video screen (p < 0.001). Accuracy was significantly better if audio conversation was possible. The quality evaluation by the consultants showed that the PDA display size and quality were sufficient for clinical use.

  18. QoE-Driven In-Network Optimization for Adaptive Video Streaming Based on Packet Sampling Measurements

    NARCIS (Netherlands)

    Bouten, Niels; de Oliveira Schmidt, R.; Famaey, Jeroen; Latré, Steven; Pras, Aiko; De Turck, Filip

    2015-01-01

    HTTP Adaptive Streaming (HAS) is becoming the de-facto standard for adaptive streaming solutions. In HAS, a video is temporally split into segments which are encoded at different quality rates. The client can then autonomously decide, based on the current buffer filling and network conditions, which

  19. Predictors of valid engagement with a video streaming web study among asian american and non-Hispanic white college students.

    Science.gov (United States)

    Park, Hanjong; Choi, Heeseung; Suarez, Marie L; Zhao, Zhongsheng; Park, Chang; Wilkie, Diana J

    2014-04-01

    The study purpose was to determine the predictors of watching most of a Web-based streaming video and whether data characteristics differed for those watching most or only part of the video. A convenience sample of 650 students (349 Asian Americans and 301 non-Hispanic whites) was recruited from a public university in the United States. Study participants were asked to view a 27-minute suicide awareness streaming video and to complete online questionnaires. Early data monitoring showed many, but not all, watched most of the video. We added software controls to facilitate video completion and defined times for a video completion group (≥26 minutes) and video noncompletion (video noncompletion group, the video completion group included more females, undergraduates, and Asian Americans, and had higher individualistic orientation and more correct manipulation check answers. The video noncompletion group skipped items in a purposeful manner, showed less interest in the video, and spent less time completing questionnaires. The findings suggest that implementing software controls, evaluating missing data patterns, documenting the amount of time spent completing questionnaires, and effective manipulation check questions are essential to control potential bias in Web-based research involving college students.

  20. Asynchronous video streaming vs. synchronous videoconferencing for teaching a pharmacogenetic pharmacotherapy course.

    Science.gov (United States)

    Moridani, Majid

    2007-02-15

    To compare students' performance and course evaluations for a pharmacogenetic pharmacotherapy course taught by synchronous videoconferencing method via the Internet and for the same course taught via asynchronous video streaming via the Internet. In spring 2005, a pharmacogenetic therapy course was taught to 73 students located on Amarillo, Lubbock, and Dallas campuses using synchronous videoconferencing, and in spring 2006, to 78 students located on the same 3 campuses using asynchronous video streaming. A course evaluation was administered to each group at the end of the courses. Students in the asynchronous setting had final course grades of 89% +/- 7% compared to the mean final course grade of 87% +/- 7% in the synchronous group (p = 0.05). Regardless of which technology was used, average course grades did not differ significantly among the 3 campus sites. Significantly more of the students in the asynchronous setting agreed (57%) with the statement that they could read the lecture notes and absorb the content on their own without attending the class than students in the synchronous class (23%; chi-square test; p videos over delivery of content using the synchronous or asynchronous method alone.

  1. Global Interoperability of High Definition Video Streams Via ACTS and Intelsat

    Science.gov (United States)

    Hsu, Eddie; Wang, Charles; Bergman, Larry; Pearman, James; Bhasin, Kul; Clark, Gilbert; Shopbell, Patrick; Gill, Mike; Tatsumi, Haruyuki; Kadowaki, Naoto

    2000-01-01

    In 1993, a proposal at the Japan.-U.S. Cooperation in Space Program Workshop lead to a subsequent series of satellite communications experiments and demonstrations, under the title of Trans-Pacific High Data Rate Satellite Communications Experiments. The first of which is a joint collaboration between government and industry teams in the United States and Japan that successfully demonstrated distributed high definition video (HDV) post-production on a global scale using a combination of high data rate satellites and terrestrial fiber optic asynchronous transfer mode (ATM) networks. The HDV experiment is the first GIBN experiment to establish a dual-hop broadband satellite link for the transmission of digital HDV over ATM. This paper describes the team's effort in using the NASA Advanced Communications Technology Satellite (ACTS) at rates up to OC-3 (155 Mbps) between Los Angeles and Honolulu, and using Intelsat at rates up to DS-3 (45 Mbps) between Kapolei and Tokyo, with which HDV source material was transmitted between Sony Pictures High Definition Center (SPHDC) in Los Angeles and Sony Visual Communication Center (VCC) in Shinagawa, Tokyo. The global-scale connection also used terrestrial networks in Japan, the States of Hawaii and California. The 1.2 Gbps digital HDV stream was compressed down to 22.5 Mbps using a proprietary Mitsubishi MPEG-2 codec that was ATM AAL-5 compatible. The codec: employed four-way parallel processing. Improved versions of the codec are now commercially available. The successful post-production activity performed in Tokyo with a HDV clip transmitted from Los Angeles was predicated on the seamless interoperation of all the equipment between the sites, and was an exciting example in deploying a global-scale information infrastructure involving a combination of broadband satellites and terrestrial fiber optic networks. Correlation of atmospheric effects with cell loss, codec drop-out, and picture quality were made. Current efforts in the

  2. Debunking a Video on Youtube as an Authentic Research Experience

    Science.gov (United States)

    Davidowsky, Philip; Rogers, Michael

    2015-01-01

    Students are exposed to a variety of unrealistic physical experiences seen in movies, video games, and short online videos. A popular classroom activity has students examine footage to identify what aspects of physics are correctly and incorrectly represented. Some of the physical phenomena pictured might be tricks or illusions made easier to…

  3. A Novel Rate Control Scheme for Constant Bit Rate Video Streaming

    Directory of Open Access Journals (Sweden)

    Venkata Phani Kumar M

    2015-08-01

    Full Text Available In this paper, a novel rate control mechanism is proposed for constant bit rate video streaming. The initial quantization parameter used for encoding a video sequence is determined using the average spatio-temporal complexity of the sequence, its resolution and the target bit rate. Simple linear estimation models are then used to predict the number of bits that would be necessary to encode a frame for a given complexity and quantization parameter. The experimental results demonstrate that our proposed rate control mechanism significantly outperforms the existing rate control scheme in the Joint Model (JM reference software in terms of Peak Signal to Noise Ratio (PSNR and consistent perceptual visual quality while achieving the target bit rate. Furthermore, the proposed scheme is validated through implementation on a miniature test-bed.

  4. Network Degradation Effects on Different Codec Types and Characteristics of Video Streaming

    Directory of Open Access Journals (Sweden)

    Jaroslav Frnda

    2014-01-01

    Full Text Available Nowadays, there is a quickly growing demand for the transmission of voice, video and data over an IP based network. Multimedia, whether we are talking about broadcast, audio and video transmission and others, from a global perspective is growing exponentially with time. With incoming requests from users, new technologies for data transfer are continually developing. Data must be delivered reliably and with the fewest losses at such high speed. Video quality as part of multimedia technology has a very important role nowadays. It is influenced by several factors, where each of them can have many forms and processing. Network performance is the major degradation effect that influences the quality of resulting image. Poor network performance (lack of link capacity, high network load… causes data packet losses or different delivery time for each packet. This work focuses exactly on these network phenomena. It examines the impact of different delays and packet losses on the quality parameters of triple play services, to evaluate the results using objective methods. The aim of this work is to bring a detailed view on the performance of video streaming over IP-based networks.

  5. Combined Wavelet Video Coding and Error Control for Internet Streaming and Multicast

    Science.gov (United States)

    Chu, Tianli; Xiong, Zixiang

    2003-12-01

    This paper proposes an integrated approach to Internet video streaming and multicast (e.g., receiver-driven layered multicast (RLM) by McCanne) based on combined wavelet video coding and error control. We design a packetized wavelet video (PWV) coder to facilitate its integration with error control. The PWV coder produces packetized layered bitstreams that are independent among layers while being embedded within each layer. Thus, a lost packet only renders the following packets in the same layer useless. Based on the PWV coder, we search for a multilayered error-control strategy that optimally trades off source and channel coding for each layer under a given transmission rate to mitigate the effects of packet loss. While both the PWV coder and the error-control strategy are new—the former incorporates embedded wavelet video coding and packetization and the latter extends the single-layered approach for RLM by Chou et al.—the main distinction of this paper lies in the seamless integration of the two parts. Theoretical analysis shows a gain of up to 1 dB on a channel with 20% packet loss using our combined approach over separate designs of the source coder and the error-control mechanism. This is also substantiated by our simulations with a gain of up to 0.6 dB. In addition, our simulations show a gain of up to 2.2 dB over previous results reported by Chou et al.

  6. Rate-Distortion Optimized Frame Dropping for Multiuser Streaming and Conversational Videos

    Directory of Open Access Journals (Sweden)

    Wei Tu

    2008-01-01

    Full Text Available We consider rate-distortion optimized strategies for dropping frames from multiple conversational and streaming videos sharing limited network node resources. The dropping strategies are based on side information that is extracted during encoding and is sent along the regular bitstream. The additional transmission overhead and the computational complexity of the proposed frame dropping schemes are analyzed. Our experimental results show that a significant improvement in end-to-end performance is achieved compared to priority-based random early dropping.

  7. DEFINITION AND ANALYSIS OF MOTION ACTIVITY AFTER-STROKE PATIENT FROM THE VIDEO STREAM

    Directory of Open Access Journals (Sweden)

    M. Yu. Katayev

    2014-01-01

    Full Text Available This article describes an approach to the assessment of motion activity of man in after-stroke period, allowing the doctor to get new information to give a more informed recommendations on rehabilitation treatment than in traditional approaches. Consider description of the hardware-software complex for determination and analysis of motion activity after-stroke patient for the video stream. The article provides a description of the complex, its algorithmic filling and the results of the work on the example of processing of the actual data. The algorithms and technology to significantly accelerate the gait analysis and improve the quality of diagnostics post-stroke patients.

  8. Videostreaming - populární fenomén. Online video není pouze streaming

    OpenAIRE

    Burachovičová, Eva

    2009-01-01

    This diploma thesis aims to provide a general overview of the issue of IP video transmission. First chapter gives in-dept introduction of the technical side of video streaming and online video generally and its functions. The second part presents the main roles of theusers and genres in this field and it also show the main social aspects of the online video technologies. The aim of the third chapter is to refer to the current use of technology and to its possible further usage. In the fourth ...

  9. Encryption for confidentiality of the network and influence of this to the quality of streaming video through network

    Science.gov (United States)

    Sevcik, L.; Uhrin, D.; Frnda, J.; Voznak, M.; Toral-Cruz, Homer; Mikulec, M.; Jakovlev, Sergej

    2015-05-01

    Nowadays, the interest in real-time services, like audio and video, is growing. These services are mostly transmitted over packet networks, which are based on IP protocol. It leads to analyses of these services and their behavior in such networks which are becoming more frequent. Video has become the significant part of all data traffic sent via IP networks. In general, a video service is one-way service (except e.g. video calls) and network delay is not such an important factor as in a voice service. Dominant network factors that influence the final video quality are especially packet loss, delay variation and the capacity of the transmission links. Analysis of video quality concentrates on the resistance of video codecs to packet loss in the network, which causes artefacts in the video. IPsec provides confidentiality in terms of safety, integrity and non-repudiation (using HMAC-SHA1 and 3DES encryption for confidentiality and AES in CBC mode) with an authentication header and ESP (Encapsulating Security Payload). The paper brings a detailed view of the performance of video streaming over an IP-based network. We compared quality of video with packet loss and encryption as well. The measured results demonstrated the relation between the video codec type and bitrate to the final video quality.

  10. Virtually numbed: Immersive video gaming alters real-life experience

    National Research Council Canada - National Science Library

    Weger, Ulrich W; Loughnan, Stephen

    2014-01-01

    ...). Does immersive video gaming, during which the player takes on the mantle of an avatar, prompt people to adopt the coldness and rigidity associated with robotic behavior and desensitize them to real-life experience...

  11. Subjective Quality Assessment of H.264/AVC Video Streaming with Packet Losses

    Directory of Open Access Journals (Sweden)

    Naccari Matteo

    2011-01-01

    Full Text Available Research in the field of video quality assessment relies on the availability of subjective scores, collected by means of experiments in which groups of people are asked to rate the quality of video sequences. The availability of subjective scores is fundamental to enable validation and comparative benchmarking of the objective algorithms that try to predict human perception of video quality by automatically analyzing the video sequences, in a way to support reproducible and reliable research results. In this paper, a publicly available database of subjective quality scores and corrupted video sequences is described. The scores refer to 156 sequences at CIF and 4CIF spatial resolutions, encoded with H.264/AVC and corrupted by simulating the transmission over an error-prone network. The subjective evaluation has been performed by 40 subjects at the premises of two academic institutions, in standard-compliant controlled environments. In order to support reproducible research in the field of full-reference, reduced-reference, and no-reference video quality assessment algorithms, both the uncompressed files and the H.264/AVC bitstreams, as well as the packet loss patterns, have been made available to the research community.

  12. Cross-Layer Techniques for Adaptive Video Streaming over Wireless Networks

    Directory of Open Access Journals (Sweden)

    Yufeng Shan

    2005-02-01

    Full Text Available Real-time streaming media over wireless networks is a challenging proposition due to the characteristics of video data and wireless channels. In this paper, we propose a set of cross-layer techniques for adaptive real-time video streaming over wireless networks. The adaptation is done with respect to both channel and data. The proposed novel packetization scheme constructs the application layer packet in such a way that it is decomposed exactly into an integer number of equal-sized radio link protocol (RLP packets. FEC codes are applied within an application packet at the RLP packet level rather than across different application packets and thus reduce delay at the receiver. A priority-based ARQ, together with a scheduling algorithm, is applied at the application layer to retransmit only the corrupted RLP packets within an application layer packet. Our approach combines the flexibility and programmability of application layer adaptations, with low delay and bandwidth efficiency of link layer techniques. Socket-level simulations are presented to verify the effectiveness of our approach.

  13. Cross-Layer Techniques for Adaptive Video Streaming over Wireless Networks

    Science.gov (United States)

    Shan, Yufeng

    2005-12-01

    Real-time streaming media over wireless networks is a challenging proposition due to the characteristics of video data and wireless channels. In this paper, we propose a set of cross-layer techniques for adaptive real-time video streaming over wireless networks. The adaptation is done with respect to both channel and data. The proposed novel packetization scheme constructs the application layer packet in such a way that it is decomposed exactly into an integer number of equal-sized radio link protocol (RLP) packets. FEC codes are applied within an application packet at the RLP packet level rather than across different application packets and thus reduce delay at the receiver. A priority-based ARQ, together with a scheduling algorithm, is applied at the application layer to retransmit only the corrupted RLP packets within an application layer packet. Our approach combines the flexibility and programmability of application layer adaptations, with low delay and bandwidth efficiency of link layer techniques. Socket-level simulations are presented to verify the effectiveness of our approach.

  14. New architecture for MPEG video streaming system with backward playback support.

    Science.gov (United States)

    Fu, Chang-Hong; Chan, Yui-Lam; Ip, Tak-Piu; Siu, Wan-Chi

    2007-09-01

    MPEG digital video is becoming ubiquitous for video storage and communications. It is often desirable to perform various video cassette recording (VCR) functions such as backward playback in MPEG videos. However, the predictive processing techniques employed in MPEG severely complicate the backward-play operation. A straightforward implementation of backward playback is to transmit and decode the whole group-of-picture (GOP), store all the decoded frames in the decoder buffer, and play the decoded frames in reverse order. This approach requires a significant buffer in the decoder, which depends on the GOP size, to store the decoded frames. This approach could not be possible in a severely constrained memory requirement. Another alternative is to decode the GOP up to the current frame to be displayed, and then go back to decode the GOP again up to the next frame to be displayed. This approach does not need the huge buffer, but requires much higher bandwidth of the network and complexity of the decoder. In this paper, we propose a macroblock-based algorithm for an efficient implementation of the MPEG video streaming system to provide backward playback over a network with the minimal requirements on the network bandwidth and the decoder complexity. The proposed algorithm classifies macroblocks in the requested frame into backward macroblocks (BMBs) and forward/backward macroblocks (FBMBs). Two macroblock-based techniques are used to manipulate different types of macroblocks in the compressed domain and the server then sends the processed macroblocks to the client machine. For BMBs, a VLC-domain technique is adopted to reduce the number of macroblocks that need to be decoded by the decoder and the number of bits that need to be sent over the network in the backward-play operation. We then propose a newly mixed VLC/DCT-domain technique to handle FBMBs in order to further reduce the computational complexity of the decoder. With these compressed-domain techniques, the

  15. A Video Game Platform for Exploring Satellite and In-Situ Data Streams

    Science.gov (United States)

    Cai, Y.

    2014-12-01

    Exploring spatiotemporal patterns of moving objects are essential to Earth Observation missions, such as tracking, modeling and predicting movement of clouds, dust, plumes and harmful algal blooms. Those missions involve high-volume, multi-source, and multi-modal imagery data analysis. Analytical models intend to reveal inner structure, dynamics, and relationship of things. However, they are not necessarily intuitive to humans. Conventional scientific visualization methods are intuitive but limited by manual operations, such as area marking, measurement and alignment of multi-source data, which are expensive and time-consuming. A new development of video analytics platform has been in progress, which integrates the video game engine with satellite and in-situ data streams. The system converts Earth Observation data into articulated objects that are mapped from a high-dimensional space to a 3D space. The object tracking and augmented reality algorithms highlight the objects' features in colors, shapes and trajectories, creating visual cues for observing dynamic patterns. The head and gesture tracker enable users to navigate the data space interactively. To validate our design, we have used NASA SeaWiFS satellite images of oceanographic remote sensing data and NOAA's in-situ cell count data. Our study demonstrates that the video game system can reduce the size and cost of traditional CAVE systems in two to three orders of magnitude. This system can also be used for satellite mission planning and public outreaching.

  16. Empirical evaluation of H.265/HEVC-based dynamic adaptive video streaming over HTTP (HEVC-DASH)

    Science.gov (United States)

    Irondi, Iheanyi; Wang, Qi; Grecos, Christos

    2014-05-01

    Real-time HTTP streaming has gained global popularity for delivering video content over Internet. In particular, the recent MPEG-DASH (Dynamic Adaptive Streaming over HTTP) standard enables on-demand, live, and adaptive Internet streaming in response to network bandwidth fluctuations. Meanwhile, emerging is the new-generation video coding standard, H.265/HEVC (High Efficiency Video Coding) promises to reduce the bandwidth requirement by 50% at the same video quality when compared with the current H.264/AVC standard. However, little existing work has addressed the integration of the DASH and HEVC standards, let alone empirical performance evaluation of such systems. This paper presents an experimental HEVC-DASH system, which is a pull-based adaptive streaming solution that delivers HEVC-coded video content through conventional HTTP servers where the client switches to its desired quality, resolution or bitrate based on the available network bandwidth. Previous studies in DASH have focused on H.264/AVC, whereas we present an empirical evaluation of the HEVC-DASH system by implementing a real-world test bed, which consists of an Apache HTTP Server with GPAC, an MP4Client (GPAC) with open HEVC-based DASH client and a NETEM box in the middle emulating different network conditions. We investigate and analyze the performance of HEVC-DASH by exploring the impact of various network conditions such as packet loss, bandwidth and delay on video quality. Furthermore, we compare the Intra and Random Access profiles of HEVC coding with the Intra profile of H.264/AVC when the correspondingly encoded video is streamed with DASH. Finally, we explore the correlation among the quality metrics and network conditions, and empirically establish under which conditions the different codecs can provide satisfactory performance.

  17. [Assessment of learning activities using streaming video for laboratory practice education: aiming for development of E-learning system that promotes self-learning].

    Science.gov (United States)

    Takeda, Naohito; Takeuchi, Isao; Haruna, Mitsumasa

    2007-12-01

    In order to develop an e-learning system that promotes self-learning, lectures and basic operations in laboratory practice of chemistry were recorded and edited on DVD media, consisting of 8 streaming videos as learning materials. Twenty-six students wanted to watch the DVD, and answered the following questions after they had watched it: "Do you think the video would serve to encourage you to study independently in the laboratory practice?" Almost all students (95%) approved of its usefulness, and more than 60% of them watched the videos repeatedly in order to acquire deeper knowledge and skill of the experimental operations. More than 60% answered that the demonstration-experiment should be continued in the laboratory practice, in spite of distribution of the DVD media.

  18. Combined Wavelet Video Coding and Error Control for Internet Streaming and Multicast

    Directory of Open Access Journals (Sweden)

    Tianli Chu

    2003-01-01

    Full Text Available This paper proposes an integrated approach to Internet video streaming and multicast (e.g., receiver-driven layered multicast (RLM by McCanne based on combined wavelet video coding and error control. We design a packetized wavelet video (PWV coder to facilitate its integration with error control. The PWV coder produces packetized layered bitstreams that are independent among layers while being embedded within each layer. Thus, a lost packet only renders the following packets in the same layer useless. Based on the PWV coder, we search for a multilayered error-control strategy that optimally trades off source and channel coding for each layer under a given transmission rate to mitigate the effects of packet loss. While both the PWV coder and the error-control strategy are new—the former incorporates embedded wavelet video coding and packetization and the latter extends the single-layered approach for RLM by Chou et al.—the main distinction of this paper lies in the seamless integration of the two parts. Theoretical analysis shows a gain of up to 1 dB on a channel with 20% packet loss using our combined approach over separate designs of the source coder and the error-control mechanism. This is also substantiated by our simulations with a gain of up to 0.6 dB. In addition, our simulations show a gain of up to 2.2 dB over previous results reported by Chou et al.

  19. Clients experience of video recordings of their psychotherapy

    DEFF Research Database (Denmark)

    Jacobsen, Claus Haugaard; Jensen, Karen Boelt; Madsen, Ninna Skov

    the current relatively widespread use video one finds only a very limited numbers empirical study of how these recordings is experienced by the clients. Aim: After a brief discussion of the pro and cons of the use of video recordings this paper presents a qualitative, explorative study of clients’ experiences......Background: Due to the development of technologies and the low costs video recording of psychotherapy sessions have gained ground in training and supervision. While some praise the advantages others decline to use this technological aid for ethical, theoretical or clinical reasons. Despite...

  20. Student-Centred Experiments with Stream Invertebrates

    Science.gov (United States)

    Vaughan, Ian; Larsen, Stefano; Durance, Isabelle; Ormerod, Steve

    2011-01-01

    Field experiments are at the core of ecology, yet rarely find their way into education, probably due to a combination of technical challenges and risks associated with fieldwork. This may compromise student education and perception of the subject, making interesting, readily manageable experiments extremely important. We describe how the daily…

  1. Scalable Video Streaming for Single-Hop Wireless Networks Using a Contention-Based Access MAC Protocol

    Directory of Open Access Journals (Sweden)

    Monchai Lertsutthiwong

    2008-07-01

    Full Text Available Limited bandwidth and high packet loss rate pose a serious challenge for video streaming applications over wireless networks. Even when packet loss is not present, the bandwidth fluctuation, as a result of an arbitrary number of active flows in an IEEE 802.11 network, can significantly degrade the video quality. This paper aims to enhance the quality of video streaming applications in wireless home networks via a joint optimization of video layer-allocation technique, admission control algorithm, and medium access control (MAC protocol. Using an Aloha-like MAC protocol, we propose a novel admission control framework, which can be viewed as an optimization problem that maximizes the average quality of admitted videos, given a specified minimum video quality for each flow. We present some hardness results for the optimization problem under various conditions and propose some heuristic algorithms for finding a good solution. In particular, we show that a simple greedy layer-allocation algorithm can perform reasonably well, although it is typically not optimal. Consequently, we present a more expensive heuristic algorithm that guarantees to approximate the optimal solution within a constant factor. Simulation results demonstrate that our proposed framework can improve the video quality up to 26% as compared to those of the existing approaches.

  2. Streaming video-based 3D reconstruction method compatible with existing monoscopic and stereoscopic endoscopy systems

    Science.gov (United States)

    Bouma, Henri; van der Mark, Wannes; Eendebak, Pieter T.; Landsmeer, Sander H.; van Eekeren, Adam W. M.; ter Haar, Frank B.; Wieringa, F. Pieter; van Basten, Jean-Paul

    2012-06-01

    Compared to open surgery, minimal invasive surgery offers reduced trauma and faster recovery. However, lack of direct view limits space perception. Stereo-endoscopy improves depth perception, but is still restricted to the direct endoscopic field-of-view. We describe a novel technology that reconstructs 3D-panoramas from endoscopic video streams providing a much wider cumulative overview. The method is compatible with any endoscope. We demonstrate that it is possible to generate photorealistic 3D-environments from mono- and stereoscopic endoscopy. The resulting 3D-reconstructions can be directly applied in simulators and e-learning. Extended to real-time processing, the method looks promising for telesurgery or other remote vision-guided tasks.

  3. Inexpensive, realtime tele-ultrasound using a commercial, web-based video streaming device.

    Science.gov (United States)

    Paulus, Yannis M; Thompson, Noel P

    2012-06-01

    We have devised an inexpensive, web-based tele-ultrasound system using commercially-available video streaming equipment. We examined the spatial and grey scale resolution, and the delay time of the system. The receiving PC was tested at various distances from the transmitting site, from 3.2 km to 4828 km. Standard resolution targets and echocardiography movie strips recorded on DVDs were used to assess the image quality. A qualitative assessment was made by an expert sonographer. As the distance between the transmitter and the receiver increased, the scan smoothness decreased and the delay increased. At a distance of 3.2 km the delay was 2-3 s, and at 4828 km it was 10-15 s. The delay was short enough to allow realtime guidance of the scanning technician by telephone. The system allows inexpensive, readily available, realtime tele-ultrasonography.

  4. Performance Analysis of Multicast Video Streaming in IEEE 802.11 b/g/n Testbed Environment

    Science.gov (United States)

    Kostuch, Aleksander; Gierłowski, Krzysztof; Wozniak, Jozef

    The aim of the work is to analyse capabilities and limitations of different IEEE 802.11 technologies (IEEE 802.11 b/g/n), utilized for both multicast and unicast video streaming transmissions directed to mobile devices. Our preliminary research showed that results obtained with currently popular simulation tools can be drastically different than these possible in real-world environment, so, in order to correctly evaluate performance of video streaming, a simple wireless test-bed infrastructure has been created. The results show a strong dependence of the quality of video streaming on the chosen transmission technology. At the same time there are significant differences in perception quality between multicast (1:n) and unicast (1:1) streams, and also between devices offered by different manufacturers. The overall results seem to demonstrate, that, while multicast support quality in different products is still varied and often requires additional configuration, it is possible to select a WiFi access point model and determine the best system parameters to ensure a good video transfer conditions in terms of acceptable QoP/E (Quality of Perception/Exellence).

  5. The Real Time Remote Motion Control of Two Wheeled Mobile Balance Robot by Using Video Streaming

    Directory of Open Access Journals (Sweden)

    Ali Unluturk

    2016-01-01

    Full Text Available This study presents the motion control of a real time two wheeled balance robot capable of moving back and forward, turning right and left and video streaming via IP (Internet Protocol camera on it. A C++ based visual user interface is created on PC (Personal Computer in order to control of the designed Two Wheeled Mobile Balance Robot (TWMBR. By means of the interface, all controller parameters of the robot can be changed via wireless communication module on it. Moreover, the robot’s tilt angle with respect to time, linear displacement and controller output can be observed simultaneously. Within the robot control interface, the videos from IP camera is transferred into the operator screen via TCP/IP (Transmission Control Protocol/Internet Protocol communication protocol. So, the robot can be controlled via arrow keys and visual interface on PC remotely by an operator. Acceleration and gyro sensors are fused by means of a real-time Kalman Filter so that robot can keep its balance in both moving and stable state in the designed system. Thus, an accurate tilt angle control is realized. Classic PID (Proportional-Integral-Derivative algorithm is used as robot controller. In conclusion, via IP camera on the robot, the real-time motion control is performed and data diagrams about motion control are obtained.

  6. FaceTime validation study: Low-cost streaming video for cytology adequacy assessment.

    Science.gov (United States)

    Agarwal, Shweta; Zhao, Lichao; Zhang, Roy; Hassell, Lewis

    2016-03-01

    Adequacy assessment for fine-needle aspiration procedures is a standard of care in large medical centers. Although the benefits of this approach include higher adequacy rates with fewer passes, it costs cytopathologist time and affects other clinical responsibilities. The objective of the current study was to evaluate the use of mobile video streaming (FaceTime) technology with the help of smartphone adapters attached to microscopes for remote adequacy assessment of cytologic samples. The study consisted of 2 phases: Phase 1 was a retrospective assessment of 25 samples by a primary pathologist with simultaneous streaming to a second pathologist using a smartphone (iPhone/iPad) FaceTime connection. Data on the adequacy of each sample and preliminary diagnoses were recorded. In phase 2, live cases were assessed prospectively by an onsite primary pathologist and by a remote pathologist using an iPhone/iPad-FaceTime connection. The testing phase involved prospective assessment of additional samples with a resident or cytotechnologist as the slide driver. In phase 1, retrospective evaluation of 25 samples yielded considerable agreement (22 of 25 samples; 88%) between onsite and remote adequacy assessments. Three samples (12%) yielded results that did not agree, including 2 samples that were read as adequate in the onsite evaluation that were assessed as indeterminate using FaceTime. In phase 2 and in the testing phase, 14 samples exhibited considerable agreement on both adequacy and preliminary diagnosis (6 samples in phase 2 and 8 samples in the testing phase) and are currently available for reporting. Problems encountered include software version standardization, camera alignment, and (rarely) comprehension of the audio stream. The current data indicate that iPhone/iPad FaceTime technology can be used to perform remote adequacy assessments of fine-needle aspirations and can help save valuable time for pathologists. © 2015 American Cancer Society.

  7. The Use and Experience of the New Video Media among Children and Young Adolescents.

    Science.gov (United States)

    Kubey, Robert; Larson, Reed

    1990-01-01

    Examines the use and experience of music videos, video games, and videocassettes among children and young adolescents. Finds that boys reacted with greater arousal and more positive affective states to new video media as compared to traditional media, while girls reported lower affect and arousal, expecially during video games and music videos.…

  8. Experiments in MPEG-4 content authoring, browsing, and streaming

    Science.gov (United States)

    Puri, Atul; Schmidt, Robert L.; Basso, Andrea; Civanlar, Mehmet R.

    2000-12-01

    In this paper, within the context of the MPEG-4 standard we report on preliminary experiments in three areas -- authoring of MPEG-4 content, a player/browser for MPEG-4 content, and streaming of MPEG-4 content. MPEG-4 is a new standard for coding of audiovisual objects; the core of MPEG-4 standard is complete while amendments are in various stages of completion. MPEG-4 addresses compression of audio and visual objects, their integration by scene description, and interactivity of users with such objects. MPEG-4 scene description is based on VRML like language for 3D scenes, extended to 2D scenes, and supports integration of 2D and 3D scenes. This scene description language is called BIFS. First, we introduce the basic concepts behind BIFS and then show with an example, textual authoring of different components needed to describe an audiovisual scene in BIFS; the textual BIFS is then saved as compressed binary file/s for storage or transmission. Then, we discuss a high level design of an MPEG-4 player/browser that uses the main components from authoring such as encoded BIFS stream, media files it refers to, and multiplexed object descriptor stream to play an MPEG-4 scene. We also discuss our extensions to such a player/browser. Finally, we present our work in streaming of MPEG-4 -- the payload format, modification to client MPEG-4 player/browser, server-side infrastructure and example content used in our MPEG-4 streaming experiments.

  9. Students’ experiences of ability-based streaming in vocational education

    DEFF Research Database (Denmark)

    Tanggaard, Lene; Nielsen, Klaus; Jørgensen, Christian Helms

    2015-01-01

    Since 2007, it has been mandatory for all vocational schools in Denmark to assess the prior qualifications of all students when they begin at the school and to use this assessment to divide students into different ability-based courses (streaming) with the aim of increasing the retention of stude......Since 2007, it has been mandatory for all vocational schools in Denmark to assess the prior qualifications of all students when they begin at the school and to use this assessment to divide students into different ability-based courses (streaming) with the aim of increasing the retention...... of students. The purpose of this paper is to explore students’ experiences of being placed on a low-ability course by using case studies of two classes from separate vocational schools in Denmark with different practices regarding the streaming of students....

  10. An Analysis of Quality of Service (QoS In Live Video Streaming Using Evolved HSPA Network Media

    Directory of Open Access Journals (Sweden)

    Achmad Zakaria Azhar

    2016-10-01

    Full Text Available Evolved High Speed Packet Access (HSPA+ is a mobile telecommunication system technology and the evolution of HSPA technology. This technology has a packet data based service with downlink speeds up to 21.1 Mbps and uplink speed up to 11.5 Mbps on the bandwidth 5MHz. This technology is expected to fulfill and support the needs for information that involves all aspects of multimedia such as video and audio, especially live video streaming. By utilizing this technology it will facilitate communicating the information, for example to monitoring the situation of the house, the news coverage at some certain area, and other events in real time. This thesis aims to identify and test the Quality of Service (QoS performance on the network that is used for live video streaming with the parameters of throughput, delay, jitter and packet loss. The software used for monitoring the data traffic of the live video streaming network is wireshark network analyzer. From the test results it is obtained that the average throughput of provider B is 5,295 Kbps bigger than the provider A, the average delay of provider B is 0.618 ms smaller than the provider A, the average jitter of provider B is 0.420 ms smaller than the provider A and the average packet loss of provider B is 0.451% smaller than the provider A.

  11. Real-time Video-Streaming to Surgical Loupe Mounted Head-Up Display for Navigated Meningioma Resection.

    Science.gov (United States)

    Diaz, Roberto; Yoon, Jang; Chen, Robert; Quinones-Hinojosa, Alfredo; Wharen, Robert; Komotar, Ricardo

    2017-04-30

    Wearable technology interfaces with normal human movement and function, thereby enabling more efficient and adaptable use.We developed a wearable display system for use with intra-operative neuronavigation for brain tumor surgery. The Google glass head-up display system was adapted to surgical loupes with a video-streaming integrated hardware and software device for display of the Stealth S7 navigation screen. Phantom trials of surface ventriculostomy were performed. The device was utilized as an alternative display screen during cranial surgery. Image-guided brain tumor resection was accomplished using Google Glass head-up display of Stealth S7 navigation images. Visual display consists of navigation video-streaming over a wireless network. The integrated system developed for video-streaming permits video data display to the operating surgeon without requiring movement of the head away from the operative field. Google Glass head-up display can be used for intra-operative neuronavigation in the setting of intracranial tumor resection.

  12. Technology consumption and cognitive control: Contrasting action video game experience with media multitasking

    Science.gov (United States)

    Cardoso-Leite, Pedro; Kludt, Rachel; Vignola, Gianluca; Ma, Wei Ji; Green, C. Shawn; Bavelier, Daphne

    2015-01-01

    Technology has the potential to impact cognition in many ways. Here we contrast two forms of technology usage: 1) media multitasking (i.e., the simultaneous consumption of multiple streams of media, such a texting while watching TV) and 2) playing action video games (a particular sub-type of video game). Previous work has outlined an association between high levels of media multitasking and specific deficits in handling distracting information, while playing action video games has been associated with enhanced attentional control. As these two factors are linked with reasonably opposing effects, failing to take them jointly into account may result in inappropriate conclusions as to the impact of technology use on attention. Across four experiments (AX-CPT, N-back, Task-switching and Filter task), testing different aspects of attention and cognition, we show that heavy media multitaskers perform worse than light media multitaskers. Contrary to previous reports though, the performance deficit was not specifically tied to distractors, but was instead more global in nature. Interestingly, participants with intermediate levels of media multitasking occasionally performed better than both light and heavy media multitaskers suggesting that the effects of increasing media multitasking are not monotonic. Action video game players, as expected, outperformed non-video game players on all tasks. However, surprisingly this was true only for participants with intermediate levels of media multitasking, suggesting that playing action video games does not protect against the deleterious effect of heavy media multitasking. Taken together this study shows that media consumption can have complex and counter-intuitive effects on attentional control. PMID:26474982

  13. Detailed Performance and Waiting-Time Predictability Analysis of Scheduling Options in On-Demand Video Streaming

    Directory of Open Access Journals (Sweden)

    Alsmirat MohammadA

    2010-01-01

    Full Text Available The number of on-demand video streams that can be supported concurrently is highly constrained by the stringent requirements of real-time playback and high transfer rates. To address this problem, stream merging techniques utilize the multicast facility to increase resource sharing. The achieved resource sharing depends greatly on how the waiting requests are scheduled for service. We investigate the effectiveness of the recently proposed cost-based scheduling in detail and analyze opportunities for further tunings and enhancements. In particular, we analyze alternative ways to compute the delivery cost. In addition, we propose a new scheduling policy, called Predictive Cost-Based Scheduling (PCS, which applies a prediction algorithm to predict future scheduling decisions and then uses the prediction results to potentially alter its current scheduling decisions. Moreover, we propose an enhancement technique, called Adaptive Regular Stream Triggering (ART, which significantly enhances stream merging behavior by selectively delaying the initiation of full-length video streams. We analyze the effectiveness of the proposed strategies in terms of their performance effectiveness and impacts on waiting-time predictability through extensive simulation. The results show that significant performance benefits as well as better waiting-time predictability can be attained.

  14. Cross-layer ultrasound video streaming over mobile WiMAX and HSUPA networks.

    Science.gov (United States)

    Alinejad, Ali; Philip, Nada Y; Istepanian, Robert S H

    2012-01-01

    It is well known that the evolution of 4G-based mobile multimedia network systems will contribute significantly to future mobile healthcare (m-health) applications that require high bandwidth and fast data rates. Central to the success of such emerging applications is the compatibility of broadband networks, such as mobile Worldwide Interoperability For Microwave Access (WiMAX) and High-Speed Uplink Packet Access (HSUPA), and especially their rate adaption issues combined with the acceptable real-time medical quality of service requirements. In this paper, we address the relevant challenges of cross-layer design requirements for real-time rate adaptation of ultrasound video streaming in mobile WiMAX and HSUPA networks. A comparative performance analysis of such approach is validated in two experimental m-health test bed systems for both mobile WiMAX and HSUPA networks. The experimental results have shown an improved performance of mobile WiMAX compared to the HSUPA using the same cross-layer optimization approach.

  15. Tunneling Horizontal IEC 61850 Traffic through Audio Video Bridging Streams for Flexible Microgrid Control and Protection

    Directory of Open Access Journals (Sweden)

    Michael Short

    2016-03-01

    Full Text Available In this paper, it is argued that some low-level aspects of the usual IEC 61850 mapping to Ethernet are not well suited to microgrids due to their dynamic nature and geographical distribution as compared to substations. It is proposed that the integration of IEEE time-sensitive networking (TSN concepts (which are currently implemented as audio video bridging (AVB technologies within an IEC 61850 / Manufacturing Message Specification framework provides a flexible and reconfigurable platform capable of overcoming such issues. A prototype test platform and bump-in-the-wire device for tunneling horizontal traffic through AVB are described. Experimental results are presented for sending IEC 61850 GOOSE (generic object oriented substation events and SV (sampled values messages through AVB tunnels. The obtained results verify that IEC 61850 event and sampled data may be reliably transported within the proposed framework with very low latency, even over a congested network. It is argued that since AVB streams can be flexibly configured from one or more central locations, and bandwidth reserved for their data ensuring predictability of delivery, this gives a solution which seems significantly more reliable than a pure MMS-based solution.

  16. Fragility issues of medical video streaming over 802.11e-WLAN m-health environments.

    Science.gov (United States)

    Tan, Yow-Yiong Edwin; Philip, Nada; Istepanian, Robert H

    2006-01-01

    This paper presents some of the fragility issues of a medical video streaming over 802.11e-WLAN in m-health applications. In particular, we present a medical channel-adaptive fair allocation (MCAFA) scheme for enhanced QoS support for IEEE 802.11 (WLAN), as a modification for the standard 802.11e enhanced distributed coordination function (EDCF) is proposed for enhanced medical data performance. The medical channel-adaptive fair allocation (MCAFA) proposed extends the EDCF, by halving the contention window (CW) after zeta consecutive successful transmissions to reduce the collision probability when channel is busy. Simulation results show that MCAFA outperforms EDCF in-terms of overall performance relevant to the requirements of high throughput of medical data and video streaming traffic in 3G/WLAN wireless environments.

  17. Unequal Protection of Video Streaming through Adaptive Modulation with a Trizone Buffer over Bluetooth Enhanced Data Rate

    Directory of Open Access Journals (Sweden)

    Rouzbeh Razavi

    2007-12-01

    Full Text Available Bluetooth enhanced data rate wireless channel can support higher-quality video streams compared to previous versions of Bluetooth. Packet loss when transmitting compressed data has an effect on the delivered video quality that endures over multiple frames. To reduce the impact of radio frequency noise and interference, this paper proposes adaptive modulation based on content type at the video frame level and content importance at the macroblock level. Because the bit rate of protected data is reduced, the paper proposes buffer management to reduce the risk of buffer overflow. A trizone buffer is introduced, with a varying unequal protection policy in each zone. Application of this policy together with adaptive modulation results in up to 4 dB improvement in objective video quality compared to fixed rate scheme for an additive white Gaussian noise channel and around 10 dB for a Gilbert-Elliott channel. The paper also reports a consistent improvement in video quality over a scheme that adapts to channel conditions by varying the data rate without accounting for the video frame packet type or buffer congestion.

  18. Unequal Protection of Video Streaming through Adaptive Modulation with a Trizone Buffer over Bluetooth Enhanced Data Rate

    Directory of Open Access Journals (Sweden)

    Razavi Rouzbeh

    2008-01-01

    Full Text Available Abstract Bluetooth enhanced data rate wireless channel can support higher-quality video streams compared to previous versions of Bluetooth. Packet loss when transmitting compressed data has an effect on the delivered video quality that endures over multiple frames. To reduce the impact of radio frequency noise and interference, this paper proposes adaptive modulation based on content type at the video frame level and content importance at the macroblock level. Because the bit rate of protected data is reduced, the paper proposes buffer management to reduce the risk of buffer overflow. A trizone buffer is introduced, with a varying unequal protection policy in each zone. Application of this policy together with adaptive modulation results in up to 4 dB improvement in objective video quality compared to fixed rate scheme for an additive white Gaussian noise channel and around 10 dB for a Gilbert-Elliott channel. The paper also reports a consistent improvement in video quality over a scheme that adapts to channel conditions by varying the data rate without accounting for the video frame packet type or buffer congestion.

  19. Researching Human Experience: video intervention/prevention assessment (VIA

    Directory of Open Access Journals (Sweden)

    Jennifer Patashnick

    2005-05-01

    Full Text Available Human experience is a critical subject for research. By discussing Video Intervention/Prevention Assessment (VIA, a patient-centered health research method where patients teach their clinicians about living with a chronic condition through the creation of visual illness narratives, this paper examines the value of qualitative inquiry and why human experience rarely is investigated directly. An analysis of a sample VIA data is presented to demonstrate how, by utilizing grounded theory and qualitative analysis, one can derive rich and unique information from human experience.

  20. GOP-based channel rate allocation using genetic algorithm for scalable video streaming over error-prone networks.

    Science.gov (United States)

    Fang, Tao; Chau, Lap-Pui

    2006-06-01

    In this paper, we address the problem of unequal error protection (UEP) for scalable video transmission over wireless packet-erasure channel. Unequal amounts of protection are allocated to the different frames (I- or P-frame) of a group-of-pictures (GOP), and in each frame, unequal amounts of protection are allocated to the progressive bit-stream of scalable video to provide a graceful degradation of video quality as packet loss rate varies. We use a genetic algorithm (GA) to quickly get the allocation pattern, which is hard to get with other conventional methods, like hill-climbing method. Theoretical analysis and experimental results both demonstrate the advantage of the proposed algorithm.

  1. Real-time skin feature identification in a time-sequential video stream

    Science.gov (United States)

    Kramberger, Iztok

    2005-04-01

    Skin color can be an important feature when tracking skin-colored objects. Particularly this is the case for computer-vision-based human-computer interfaces (HCI). Humans have a highly developed feeling of space and, therefore, it is reasonable to support this within intelligent HCI, where the importance of augmented reality can be foreseen. Joining human-like interaction techniques within multimodal HCI could, or will, gain a feature for modern mobile telecommunication devices. On the other hand, real-time processing plays an important role in achieving more natural and physically intuitive ways of human-machine interaction. The main scope of this work is the development of a stereoscopic computer-vision hardware-accelerated framework for real-time skin feature identification in the sense of a single-pass image segmentation process. The hardware-accelerated preprocessing stage is presented with the purpose of color and spatial filtering, where the skin color model within the hue-saturation-value (HSV) color space is given with a polyhedron of threshold values representing the basis of the filter model. An adaptive filter management unit is suggested to achieve better segmentation results. This enables the adoption of filter parameters to the current scene conditions in an adaptive way. Implementation of the suggested hardware structure is given at the level of filed programmable system level integrated circuit (FPSLIC) devices using an embedded microcontroller as their main feature. A stereoscopic clue is achieved using a time-sequential video stream, but this shows no difference for real-time processing requirements in terms of hardware complexity. The experimental results for the hardware-accelerated preprocessing stage are given by efficiency estimation of the presented hardware structure using a simple motion-detection algorithm based on a binary function.

  2. Analyzing Motives, Preferences, and Experiences in Video Game Play

    Directory of Open Access Journals (Sweden)

    Donald Loffredo

    2017-04-01

    Full Text Available This paper presents the results of analyzing motives, preferences, and experiences in video game play. A sample of 112 (64 male and 48 female students completed online the Gaming Attitudes, Motives, and Experiences Scales (GAMES. Separate one-way independent-measures multivariate analyses of variance (MANOVAs were used to determine if there were statistically significant differences by gender, age category, hours of videogame play, and ethnicity on the nine Factor Subscales of the GAMES. The results supported two of the proposed hypotheses. There were statistically differences by gender and hours of videogame play on some of the Factor Subscales of the GAMES.

  3. Flume experiments on scour downstream of wood stream restoration structures

    Science.gov (United States)

    Pagliara, Stefano; Kurdistani, Sahameddin Mahmoudi

    2017-02-01

    River restoration aims to improve physical natural form and processes of a river. Techniques to control the riverbed, stabilize channel alignment, protect stream banks, and rebuild the natural habitat are an important part of river restoration projects. Rivers can be stabilized and habitat restored through techniques such as rebuilding meanders and pool-riffle sequences and managing large wood. Structures that limit channel width to accelerate the normal flows through the constricted section are referred to as stream deflectors. Single-wing, double-wing and triangular deflectors are the most commonly used types of this measure. Log-frame deflectors consist of a triangular log frame filled with rock. Deflector constructions singly or in series in low gradient meandering streams, divert base flows toward the center of the channel and, under certain conditions, increase the depth and velocity of flow thereby creating scour pools and enhancing fish habitat. Scour characteristics and morphologies downstream of log-frame deflectors have been analyzed at the hydraulic laboratory of the University of Pisa. All experiments have been carried out in clear water conditions. The results showed that the tailwater depth plays an important role on scour characteristics. In addition, it was experimentally proven that using log-frame deflectors instead of log-deflectors result in a better river bank protection. In this case, for all the tested hydraulic conditions, the scour hole never occurred close to the channel bank. Useful empirical relationships have been proposed in order to evaluate the main features of the scour geometry.

  4. MATIN: a random network coding based framework for high quality peer-to-peer live video streaming.

    Science.gov (United States)

    Barekatain, Behrang; Khezrimotlagh, Dariush; Aizaini Maarof, Mohd; Ghaeini, Hamid Reza; Salleh, Shaharuddin; Quintana, Alfonso Ariza; Akbari, Behzad; Cabrera, Alicia Triviño

    2013-01-01

    In recent years, Random Network Coding (RNC) has emerged as a promising solution for efficient Peer-to-Peer (P2P) video multicasting over the Internet. This probably refers to this fact that RNC noticeably increases the error resiliency and throughput of the network. However, high transmission overhead arising from sending large coefficients vector as header has been the most important challenge of the RNC. Moreover, due to employing the Gauss-Jordan elimination method, considerable computational complexity can be imposed on peers in decoding the encoded blocks and checking linear dependency among the coefficients vectors. In order to address these challenges, this study introduces MATIN which is a random network coding based framework for efficient P2P video streaming. The MATIN includes a novel coefficients matrix generation method so that there is no linear dependency in the generated coefficients matrix. Using the proposed framework, each peer encapsulates one instead of n coefficients entries into the generated encoded packet which results in very low transmission overhead. It is also possible to obtain the inverted coefficients matrix using a bit number of simple arithmetic operations. In this regard, peers sustain very low computational complexities. As a result, the MATIN permits random network coding to be more efficient in P2P video streaming systems. The results obtained from simulation using OMNET++ show that it substantially outperforms the RNC which uses the Gauss-Jordan elimination method by providing better video quality on peers in terms of the four important performance metrics including video distortion, dependency distortion, End-to-End delay and Initial Startup delay.

  5. MATIN: a random network coding based framework for high quality peer-to-peer live video streaming.

    Directory of Open Access Journals (Sweden)

    Behrang Barekatain

    Full Text Available In recent years, Random Network Coding (RNC has emerged as a promising solution for efficient Peer-to-Peer (P2P video multicasting over the Internet. This probably refers to this fact that RNC noticeably increases the error resiliency and throughput of the network. However, high transmission overhead arising from sending large coefficients vector as header has been the most important challenge of the RNC. Moreover, due to employing the Gauss-Jordan elimination method, considerable computational complexity can be imposed on peers in decoding the encoded blocks and checking linear dependency among the coefficients vectors. In order to address these challenges, this study introduces MATIN which is a random network coding based framework for efficient P2P video streaming. The MATIN includes a novel coefficients matrix generation method so that there is no linear dependency in the generated coefficients matrix. Using the proposed framework, each peer encapsulates one instead of n coefficients entries into the generated encoded packet which results in very low transmission overhead. It is also possible to obtain the inverted coefficients matrix using a bit number of simple arithmetic operations. In this regard, peers sustain very low computational complexities. As a result, the MATIN permits random network coding to be more efficient in P2P video streaming systems. The results obtained from simulation using OMNET++ show that it substantially outperforms the RNC which uses the Gauss-Jordan elimination method by providing better video quality on peers in terms of the four important performance metrics including video distortion, dependency distortion, End-to-End delay and Initial Startup delay.

  6. Enhancing the Therapy Experience Using Principles of Video Game Design.

    Science.gov (United States)

    Folkins, John Wm; Brackenbury, Tim; Krause, Miriam; Haviland, Allison

    2016-02-01

    This article considers the potential benefits that applying design principles from contemporary video games may have on enhancing therapy experiences. Six principles of video game design are presented, and their relevance for enriching clinical experiences is discussed. The motivational and learning benefits of each design principle have been discussed in the education literature as having positive impacts on student motivation and learning and are related here to aspects of clinical practice. The essential experience principle suggests connecting all aspects of the experience around a central emotion or cognitive connection. The discovery principle promotes indirect learning in focused environments. The risk-taking principle addresses the uncertainties clients face when attempting newly learned skills in novel situations. The generalization principle encourages multiple opportunities for skill transfer. The reward system principle directly relates to the scaffolding of frequent and varied feedback in treatment. Last, the identity principle can assist clients in using their newly learned communication skills to redefine self-perceptions. These principles highlight areas for research and interventions that may be used to reinforce or advance current practice.

  7. Evaluating the use of streaming video to support student learning in a first-year life sciences course for student nurses.

    Science.gov (United States)

    Green, Sue M; Voegeli, David; Harrison, Maureen; Phillips, Jackie; Knowles, Jess; Weaver, Mike; Shephard, Kerry

    2003-05-01

    Streaming video was used to support the learning of first year student nurses on a Life Sciences module, as one of many innovations designed to increase the range of resources and support available to students. This paper describes the background to this innovation, the procedures adopted and the results of extensive evaluation. The use of streaming video was evaluated in three applications in the module. A total of 656 students used online directed-learning sessions that incorporated streamed video. Just over half of these students actually viewed the video streams. Their feedback showed that 32% found access easy, 59% enjoyed using the resources, and 25% were very confident that they learned from them. Different types of video were used, and embedded in diverse ways, but the results were consistent across the three applications. They suggest that streamed video can contribute to useful resources to support learning by student nurses but, for a variety of reasons, it may not appeal or be adequately accessible to all students at present.

  8. Low-cost synchronization of high-speed audio and video recordings in bio-acoustic experiments.

    Science.gov (United States)

    Laurijssen, Dennis; Verreycken, Erik; Geipel, Inga; Daems, Walter; Peremans, Herbert; Steckel, Jan

    2017-12-19

    In this paper, we present a method for synchronizing high-speed audio and video recordings of bio-acoustic experiments. By embedding a random signal into the recorded video and audio data, robust synchronization of a diverse set of sensor streams can be performed without the need to keep detailed records. The synchronization can be performed using recording devices without dedicated synchronization inputs. We demonstrate the efficacy of the approach in two sets of experiments: behavioral experiments on different species of echolocating bats and the recordings of field crickets. We present the general operating principle of the synchronization method, discuss its synchronization strength and provide insights in how to construct such a device using off-the-shelf components. © 2017. Published by The Company of Biologists Ltd.

  9. A Video Quality Assessment Method for VoIP Applications Based on User Experience

    Science.gov (United States)

    Wang, Zedong; Wang, Jing; Wang, Fei; Li, Chengcai; Fei, Zesong; Rahim, Tariq

    2017-12-01

    An objective video quality assessment method is proposed to evaluate the video quality in voice over internet protocol (VoIP) applications under network distortion. The fluency and the clarity of videos are two main parts of the factors that affect user experience, thus the method evaluates these two parts to assess the distortions of videos in VoIP applications caused by codec and packet loss. The clarity of the video is measured by calculating block artifacts and frame blurring. Video blocking artifacts are measured by splitting the picture into small blocks and calculating the difference of the pixels around each border while video blurring is measured by getting edge information through Sobel operator, and counting the gradient histogram. Then the video clarity can be measured by a weighted sum of block artifacts score and blurring score using linear regression. The scores are also normalized in order to eliminate the impact of different video contents. The video fluency is calculated by counting the wrong frame in the video. Finally, a weighted sum of video clarity score and video fluency score can represent the quality of the video. The experimental results show that the objective quality scores have a strong correlation with the subjective quality scores, and the algorithm concludes two parts of user experience other than just image quality, which is more comprehensive and it can be used in video quality assessment in VoIP applications.

  10. Video in Distance Education: ITFS vs. Web-Streaming--Evaluation of Student Attitudes

    Science.gov (United States)

    Reisslein, Jana; Seeling, Patrick; Reisslein, Martin

    2005-01-01

    The use of video in distance education courses has a long tradition, with many colleges and universities having been delivering distance education courses with video since the 80's using the Instructional Television Fixed Service (ITFS) and cable television. With the emergence of the Internet and the increased access bandwidths from private homes…

  11. Optimal JPWL Forward Error Correction Rate Allocation for Robust JPEG 2000 Images and Video Streaming over Mobile Ad Hoc Networks

    Directory of Open Access Journals (Sweden)

    Benoit Macq

    2008-07-01

    Full Text Available Based on the analysis of real mobile ad hoc network (MANET traces, we derive in this paper an optimal wireless JPEG 2000 compliant forward error correction (FEC rate allocation scheme for a robust streaming of images and videos over MANET. The packet-based proposed scheme has a low complexity and is compliant to JPWL, the 11th part of the JPEG 2000 standard. The effectiveness of the proposed method is evaluated using a wireless Motion JPEG 2000 client/server application; and the ability of the optimal scheme to guarantee quality of service (QoS to wireless clients is demonstrated.

  12. Neural contributions to flow experience during video game playing.

    Science.gov (United States)

    Klasen, Martin; Weber, René; Kircher, Tilo T J; Mathiak, Krystyna A; Mathiak, Klaus

    2012-04-01

    Video games are an exciting part of new media. Although game play has been intensively studied, the underlying neurobiology is still poorly understood. Flow theory is a well-established model developed to describe subjective game experience. In 13 healthy male subjects, we acquired fMRI data during free play of a video game and analyzed brain activity based on the game content. In accordance with flow theory, we extracted the following factors from the game content: (i) balance between ability and challenge; (ii) concentration and focus; (iii) direct feedback of action results; (iv) clear goals; and (v) control over the situation/activity. We suggest that flow is characterized by specific neural activation patterns and that the latter can be assessed-at least partially-by content factors contributing to the emergence of flow. Each of the content factors was characterized by specific and distinguishable brain activation patterns, encompassing reward-related midbrain structures, as well as cognitive and sensorimotor networks. The activation of sensory and motor networks in the conjunction analyses underpinned the central role of simulation for flow experience. Flow factors can be validated with functional brain imaging which can improve the understanding of human emotions and motivational processes during media entertainment.

  13. Publicación de materiales audiovisuales a través de un servidor de video-streaming Publication of audio-visual materials through a streaming video server

    Directory of Open Access Journals (Sweden)

    Acevedo Clavijo Edwin Jovanny

    2010-07-01

    Full Text Available Esta propuesta tiene como objetivo estudiar varias alternativas de servidores Streaming para determinar la mejor herramienta para el desarrollo de la publicación de material audiovisual educativo. Se evaluaron las plataformas más utilizadas teniendo en cuenta sus características y beneficios que tiene cada servidor entre las los cuales están: Hélix Universal Server, Windows Media Server de Microsoft, Peer Cast y Darwin Server. implementando un servidor con mayores capacidades y beneficios para la publicación de videos con fines académicos a través de la intranet de la Universidad Cooperativa de Colombia seccional Barrancabermeja This proposal has as an principal objective to study different alternatives for streaming servers to determine the best tool in the project’s development. Platforms most used were evaluated features and benefits in each served such as: Helix Universal Server, Microsoft Windows Media Server, Peer Cast and Darwin Server. Implementing a server with more capabilities and benefits for the publication of videos for academic purposes through the intranet of the Cooperative University of Colombia Barrancabermeja’s sectional

  14. Digital Video taken during the 3-person submersible Clelia dive 613 of the NOAA Office of Ocean Exploration's Islands in the Stream 2001 cruise, September 01, 2001 (NCEI Accession 0037126)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The video data in this accession was captured during the Islands in the Stream mission of 2001. Islands in the Stream was a three-month scientific expedition to...

  15. Digital video taken during the 3-person submersible Clelia dive 606 of the NOAA Office of Ocean Exploration's Islands in the Stream 2001 cruise, August 29, 2001 (NCEI Accession 0039739)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The video data in this accession was captured during the Islands in the Stream mission of 2001. Islands in the Stream was a three-month scientific expedition to...

  16. Digital Video taken during the 3-person submersible Clelia dive 609 of the NOAA Office of Ocean Exploration's Islands in the Stream 2001 cruise, August 30, 2001 (NCEI Accession 0037122)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The video data in this accession was captured during the Islands in the Stream mission of 2001. Islands in the Stream was a three-month scientific expedition to...

  17. Streaming currents in turbulent flows and metal capillaries. IV. Experiment (2). Results and conclusions

    NARCIS (Netherlands)

    Boumans, A.A.

    1957-01-01

    Some charactistic results of the experiments on the streaming current are described with the help of graphs. It is shown that in our case the streaming current in metal tubes is supplied by the wall of the tube; glass tubes give comparatively less streaming current. The mean charge density in

  18. The effects of video game experience and active stereoscopy on performance in combat identification tasks.

    Science.gov (United States)

    Keebler, Joseph R; Jentsch, Florian; Schuster, David

    2014-12-01

    We investigated the effects of active stereoscopic simulation-based training and individual differences in video game experience on multiple indices of combat identification (CID) performance. Fratricide is a major problem in combat operations involving military vehicles. In this research, we aimed to evaluate the effects of training on CID performance in order to reduce fratricide errors. Individuals were trained on 12 combat vehicles in a simulation, which were presented via either a non-stereoscopic or active stereoscopic display using NVIDIA's GeForce shutter glass technology. Self-report was used to assess video game experience, leading to four between-subjects groups: high video game experience with stereoscopy, low video game experience with stereoscopy, high video game experience without stereoscopy, and low video game experience without stereoscopy. We then tested participants on their memory of each vehicle's alliance and name across multiple measures, including photographs and videos. There was a main effect for both video game experience and stereoscopy across many of the dependent measures. Further, we found interactions between video game experience and stereoscopic training, such that those individuals with high video game experience in the non-stereoscopic group had the highest performance outcomes in the sample on multiple dependent measures. This study suggests that individual differences in video game experience may be predictive of enhanced performance in CID tasks. Selection based on video game experience in CID tasks may be a useful strategy for future military training. Future research should investigate the generalizability of these effects, such as identification through unmanned vehicle sensors.

  19. Streaming weekly soap opera video episodes to smartphones in a randomized controlled trial to reduce HIV risk in young urban African American/black women.

    Science.gov (United States)

    Jones, Rachel; Lacroix, Lorraine J

    2012-07-01

    Love, Sex, and Choices is a 12-episode soap opera video series created as an intervention to reduce HIV sex risk. The effect on women's HIV risk behavior was evaluated in a randomized controlled trial in 238 high risk, predominately African American young adult women in the urban Northeast. To facilitate on-demand access and privacy, the episodes were streamed to study-provided smartphones. Here, we discuss the development of a mobile platform to deliver the 12-weekly video episodes or weekly HIV risk reduction written messages to smartphones, including; the technical requirements, development, and evaluation. Popularity of the smartphone and use of the Internet for multimedia offer a new channel to address health disparities in traditionally underserved populations. This is the first study to report on streaming a serialized video-based intervention to a smartphone. The approach described here may provide useful insights in assessing advantages and disadvantages of smartphones to implement a video-based intervention.

  20. Benchmark experiments on neutron streaming through JET Torus Hall penetrations

    Science.gov (United States)

    Batistoni, P.; Conroy, S.; Lilley, S.; Naish, J.; Obryk, B.; Popovichev, S.; Stamatelatos, I.; Syme, B.; Vasilopoulou, T.; contributors, JET

    2015-05-01

    Neutronics experiments are performed at JET for validating in a real fusion environment the neutronics codes and nuclear data applied in ITER nuclear analyses. In particular, the neutron fluence through the penetrations of the JET torus hall is measured and compared with calculations to assess the capability of state-of-art numerical tools to correctly predict the radiation streaming in the ITER biological shield penetrations up to large distances from the neutron source, in large and complex geometries. Neutron streaming experiments started in 2012 when several hundreds of very sensitive thermo-luminescence detectors (TLDs), enriched to different levels in 6LiF/7LiF, were used to measure the neutron and gamma dose separately. Lessons learnt from this first experiment led to significant improvements in the experimental arrangements to reduce the effects due to directional neutron source and self-shielding of TLDs. Here we report the results of measurements performed during the 2013-2014 JET campaign. Data from new positions, at further locations in the South West labyrinth and down to the Torus Hall basement through the air duct chimney, were obtained up to about a 40 m distance from the plasma neutron source. In order to avoid interference between TLDs due to self-shielding effects, only TLDs containing natural Lithium and 99.97% 7Li were used. All TLDs were located in the centre of large polyethylene (PE) moderators, with natLi and 7Li crystals evenly arranged within two PE containers, one in horizontal and the other in vertical orientation, to investigate the shadowing effect in the directional neutron field. All TLDs were calibrated in the quantities of air kerma and neutron fluence. This improved experimental arrangement led to reduced statistical spread in the experimental data. The Monte Carlo N-Particle (MCNP) code was used to calculate the air kerma due to neutrons and the neutron fluence at detector positions, using a JET model validated up to the

  1. Power-Constrained Fuzzy Logic Control of Video Streaming over a Wireless Interconnect

    Directory of Open Access Journals (Sweden)

    Mohammed Ghanbari

    2008-06-01

    Full Text Available Wireless communication of video, with Bluetooth as an example, represents a compromise between channel conditions, display and decode deadlines, and energy constraints. This paper proposes fuzzy logic control (FLC of automatic repeat request (ARQ as a way of reconciling these factors, with a 40% saving in power in the worst channel conditions from economizing on transmissions when channel errors occur. Whatever the channel conditions are, FLC is shown to outperform the default Bluetooth scheme and an alternative Bluetooth-adaptive ARQ scheme in terms of reduced packet loss and delay, as well as improved video quality.

  2. Stellar streams as gravitational experiments. II. Asymmetric tails of globular cluster streams

    Science.gov (United States)

    Thomas, G. F.; Famaey, B.; Ibata, R.; Renaud, F.; Martin, N. F.; Kroupa, P.

    2018-01-01

    Kinematically cold tidal streams of globular clusters (GC) are excellent tracers of the Galactic gravitational potential at moderate Galactocentric distances, and can also be used as probes of the law of gravity on Galactic scales. Here, we compare for the first time the generation of such streams in Newtonian and Milgromian gravity (MOND). We first computed analytical results to investigate the expected shape of the GC gravitational potential in both frameworks, and we then ran N-body simulations with the Phantom of Ramses code. We find that the GCs tend to become lopsided in MOND. This is a consequence of the external field effect which breaks the strong equivalence principle. When the GC is filling its tidal radius the lopsidedness generates a strongly asymmetric tidal stream. In Newtonian dynamics, such markedly asymmetric streams can in general only be the consequence of interactions with dark matter subhalos, giant molecular clouds, or interaction with the Galactic bar. In these Newtonian cases, the asymmetry is the consequence of a very large gap in the stream, whilst in MOND it is a true asymmetry. This should thus allow us in the future to distinguish these different scenarios by making deep observations of the environment of the asymmetric stellar stream of Palomar 5. Moreover, our simulations indicate that the high internal velocity dispersion of Palomar 5 for its small stellar mass would be natural in MOND. The movie is available in electronic form at http://www.aanda.org

  3. Experience with Video Head Impulse Testing (vHIT

    Directory of Open Access Journals (Sweden)

    Carmen ÁLVAREZ-SANTACRUZ

    2017-03-01

    Full Text Available Introduction and objective: The diagnosis and study of vestibular pathology has been always guided by the medical history, exploration and caloric test. The caloric test has some limitations because it only allows the study of horizontal semicircular canal and it is also poorly tolerated by patients. Alternatively, the vHIT (Video Head Impulse Test, allows the analysis of all semicircular channels being quicker to perform and less obtrusive. The objective of the following study is to reflect our initial experience with the vHIT and compare it with another diagnosis tests. Method: This is a observational, prospective and descriptive study, of one year of observation in our Healthcare center for all patients who described symptoms of dizziness, unsteadiness or vertigo. Results: A total of 155 patients were included. There was a clear predominance of females, being Meniere's disease the most frequently diagnosed entity. The diagnosis was reached by vHIT. Caloric test was also performed in patients without definite or doubt in the diagnosis. With the data, the statistical relationships were established, being significant between sex with vestibular neuritis and vestibular migraine. There was a statistically significant relationship between vestibule-ocular reflex and caloric test associated with the previous pathologies. Discussion: The head impulse assisted video is a quick, simple and well tolerated technique without adverse symptoms like the caloric test. The disparities of results are due to differences in the stimulated frequencies, being the vHIT more physiological. Conclusions: vHIT facilitates the complementary diagnosis of acute pathology, being a well-tolerated technique. However, in pathologies with central compensation the results by vHIT may be normal, requiring the caloric test for better diagnostic approach.

  4. Meteoroid orbits from video meteors. The case of the Geminid stream

    Czech Academy of Sciences Publication Activity Database

    Hajduková jr., M.; Koten, Pavel; Kornoš, L.; Toth, J.

    2017-01-01

    Roč. 143, SI (2017), s. 89-98 ISSN 0032-0633. [Meteoroids 2016. Nordwijk, 06.06.2016-10.06.2016] R&D Projects: GA ČR GA14-25251S Institutional support: RVO:67985815 Keywords : meteors * meteoroid orbits * meteoroid streams Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 1.892, year: 2016

  5. Embracing Videos in Scholarly Publishing: The IOP Publishing Experience

    OpenAIRE

    Belsole, Elena; Dacey, James P; Navas, John

    2016-01-01

    In scholarly publishing video content has emerged in recent years as a way of conveying results beyond the written article. In 2010 New Journal of Physics started a pilot project on “video abstracts” as a means to innovate and offer authors opportunities to showcase their work. Today other IOP Publishing journals also offer this option to authors. IOP Publishing’s e-book programme also has adopted video abstracts and includes embedded video and multimedia in the e-books them...

  6. Counter-streaming radiative shock experiments on the Orion laser

    Science.gov (United States)

    Suzuki-Vidal, F.; Clayson, T.; Swadling, G. F.; Patankar, S.; Burdiak, G. C.; Lebedev, S. V.; Smith, R. A.; Stehle, C.; Chaulagain, U.; Singh, R. L.; Larour, J.; Kozlova, M.; Spindloe, C.; Foster, J.; Skidmore, J.; Gumbrell, E.; Graham, P.; Danson, C.

    2016-10-01

    The formation of radiative shocks, shocks in which the structure of density and temperature is affected by radiation from the shock-heated matter, is ubiquitous in many astrophysical scenarios. Experiments were performed at the Orion laser using a new target configuration that allows studying the formation of single and counter-streaming radiative shocks in gas-filled targets (Ne, Ar, Kr, Xe), with initial pressures 0.1-1 bar and a driver intensity of 6x1014 W/cm2 . The shocks propagate at velocities >60 km/s and were diagnosed with optical interferometry (streaked and time-resolved) and point-projection X-ray backlighting allowing to probe simultaneously the pre-shock radiative precursor and the shock front itself. Besides varying the extent of the radiative precursor the results show that different gases seem to have an effect on the shock front as evidenced by a number of spatial features. The results are compared with radiative hydrodynamics simulations in 1-D (HELIOS) and 2-D (NYM/PETRA). Supported by Orion Academic Access, the Royal Society, EPSRC, Labex PLAS@PAR. Currently at (2) LLNL, USA, (3) ELI, CZ, (4) First Light Fusion, UK.

  7. Multiple Intelligences, Motivations and Learning Experience Regarding Video-Assisted Subjects in a Rural University

    Science.gov (United States)

    Hajhashemi, Karim; Caltabiano, Nerina; Anderson, Neil; Tabibzadeh, Seyed Asadollah

    2018-01-01

    This study investigates multiple intelligences in relation to online video experiences, age, gender, and mode of learning from a rural Australian university. The inter-relationships between learners' different intelligences and their motivations and learning experience with the supplementary online videos utilised in their subjects are…

  8. Video quality assessment for web content mirroring

    Science.gov (United States)

    He, Ye; Fei, Kevin; Fernandez, Gustavo A.; Delp, Edward J.

    2014-03-01

    Due to the increasing user expectation on watching experience, moving web high quality video streaming content from the small screen in mobile devices to the larger TV screen has become popular. It is crucial to develop video quality metrics to measure the quality change for various devices or network conditions. In this paper, we propose an automated scoring system to quantify user satisfaction. We compare the quality of local videos with the videos transmitted to a TV. Four video quality metrics, namely Image Quality, Rendering Quality, Freeze Time Ratio and Rate of Freeze Events are used to measure video quality change during web content mirroring. To measure image quality and rendering quality, we compare the matched frames between the source video and the destination video using barcode tools. Freeze time ratio and rate of freeze events are measured after extracting video timestamps. Several user studies are conducted to evaluate the impact of each objective video quality metric on the subjective user watching experience.

  9. Demystifying porn 2.0:a look into a major adult video streaming website

    OpenAIRE

    Tyson, Gareth; Elkhatib, Yehia; Sastry, Nishanth; Uhlig, Steve

    2013-01-01

    The Internet has recently evolved into a huge video delivery infrastructure, with websites such as YouTube and Netflix appearing at the top of most traffic measurement studies. However, most traffic studies have largely kept silent about an area of the Internet that (even today) is poorly understood: adult media distribution. Whereas ten years ago, such services were provided primarily via peer-to-peer file sharing and bespoke websites, recently these have converged towards what is known as "...

  10. Synchronised Encoding of GPS NMEA Messages onto Hig h Definition Video Streams

    OpenAIRE

    Lewis, Paul; Winstanley, Adam C.; McCarthy, Tim

    2007-01-01

    Consumer awareness and retail penetration of high definition (HD) technologies has increased dramatically over the last few years. This has led not only to increased interest and expectation of these technologies but also affordability of equipment. Global Positioning Systems (GPS) have also seen a very dramatic increase in consumer exposure and affordability with in car navigation systems, as an example, becoming more common place. The integration of HD Video (HDV) and GPS offers new researc...

  11. Using participatory video to explore teachers' lived experiences ...

    African Journals Online (AJOL)

    A two-day participatory research-as-intervention workshop enabled twelve teachers from economically and socially disadvantaged township schools to produce videos that examined some challenges applicable to their praxis. The process of producing the participatory video offered the teachers the opportunity to learn ...

  12. Learner Outcomes and Satisfaction: A Comparison of Live Video-Streamed Instruction, Satellite Broadcast Instruction, and Face-to-Face Instruction

    Science.gov (United States)

    Abdous, M'hammed; Yoshimura, Miki

    2010-01-01

    This study examined the final grade and satisfaction level differences among students taking specific courses using three different methods: face-to-face in class, via satellite broadcasting at remote sites, and via live video-streaming at home or at work. In each case, the same course was taught by the same instructor in all three delivery…

  13. Evaluating the Use of Streaming Video To Support Student Learning in a First-Year Life Sciences Course for Student Nurses.

    Science.gov (United States)

    Green, Sue M.; Voegeli, David; Harrison, Maureen; Phillips, Jackie; Knowles, Jess; Weaver, Mike; Shepard, Kerry

    2003-01-01

    Nursing students (n=656) used streaming videos on immune, endocrine, and neurological systems using Blackboard software. Of students who viewed all three, 32% found access easy, 59% enjoyed them, and 25% felt very confident in their learning. Results were consistent across three different types and embedding methods. Technical and access problems…

  14. Cross-Layer Measurement on an IEEE 802.11g Wireless Network Supporting MPEG-2 Video Streaming Applications in the Presence of Interference

    Directory of Open Access Journals (Sweden)

    Alessandro Sona

    2010-01-01

    Full Text Available The performance of wireless local area networks supporting video streaming applications, based on MPEG-2 video codec, in the presence of interference is here dealt with. IEEE 802.11g standard wireless networks, that do not support QoS in according with IEEE 802.11e standard, are, in particular, accounted for and Bluetooth signals, additive white Gaussian noise, and competitive data traffic are considered as sources of interference. The goal is twofold: from one side, experimentally assessing and correlating the values that some performance metrics assume at the same time at different layers of an IEEE 802.11g WLAN delivering video streaming in the presence of in-channel interference; from the other side, deducing helpful and practical hints for designers and technicians, in order to efficiently assess and enhance the performance of an IEEE 802.11g WLAN supporting video streaming in some suitable setup conditions and in the presence of interference. To this purpose, an experimental analysis is planned following a cross-layer measurement approach, and a proper testbed within a semianechoic chamber is used. Valuable results are obtained in terms of signal-to-interference ratio, packet loss ratio, jitter, video quality, and interference data rate; helpful hints for designers and technicians are finally gained.

  15. Video-assisted thoracoscopic surgery lobectomy – early experience

    Directory of Open Access Journals (Sweden)

    Robert Šimon

    2010-09-01

    Full Text Available Introduction: Video-assisted thoracoscopic surgery (VATS lobectomy is the anatomical resection of a whole lobe ofthe lung followed by removal of the lymph nodes from the mediastinum using a thoracoscope and an access incision(small thoracotomy ≤ 5 cm without using the rib spreader. Aim: To present the early experience with VATS lobectomy. Material and methods: Five patients were treated surgically using the VATS technique of anatomical lung resection atthe 2nd Department of Surgery, Pavol Jozef Šafárik University, University Hospital of L. Pasteur, Košice, (Slovak Republicwithin 12 months from 10.2008 to 10.2009. Lobectomy was performed in 4 patients and pneumonectomy in 1 patient. Results: The mean operating time was 120 min (range 80-170 min. Following lobectomy a drain was inserted into thepleural cavity in 4 cases, whereas there was no drainage after 1 pneumonectomy. Drains were removed 2-5 days afterthe surgery. Four patients suffered from lung carcinoma (1 squamous cell carcinoma, 3 adenocarcinomas; 1 patienthad chondroid hamartoma. Postoperative condition was good in all patients. There were no early complications andpatients were released home on the 6th postoperative day on average. Conclusions: The advantages of VATS lobectomy have been widely discussed. There is a consensus that in elderlypatients with non-small cell lung cancer VATS lobectomy accompanied by mediastinal lymphadenectomy reduces theincidence of complications after the surgery and patients recover faster.

  16. Debunking a Video on YouTube as an Authentic Research Experience

    Science.gov (United States)

    Davidowsky, Philip; Rogers, Michael

    2015-05-01

    Students are exposed to a variety of unrealistic physical experiences seen in movies, video games, and short online videos. A popular classroom activity has students examine footage to identify what aspects of physics are correctly and incorrectly represented.1-7 Some of the physical phenomena pictured might be tricks or illusions made easier to perform with the use of video, while others are removed from their historical context, leaving the audience to form misguided conclusions about what they saw with only the information in the video. One such video in which the late Eric Laithwaite, a successful British engineer and inventor, claims that a spinning wheel "becomes light as a feather" provides an opportunity for students to investigate Laithwaite's claim.8 The use of video footage can engage students in learning physics9 but also provide an opportunity for authentic research experiences.

  17. Live-streaming: Time-lapse video evidence of novel streamer formation mechanism and varying viscosity.

    Science.gov (United States)

    Parvinzadeh Gashti, Mazeyar; Bellavance, Julien; Kroukamp, Otini; Wolfaardt, Gideon; Taghavi, Seyed Mohammad; Greener, Jesse

    2015-07-01

    Time-lapse videos of growing biofilms were analyzed using a background subtraction method, which removed camouflaging effects from the heterogeneous field of view to reveal evidence of streamer formation from optically dense biofilm segments. In addition, quantitative measurements of biofilm velocity and optical density, combined with mathematical modeling, demonstrated that streamer formation occurred from mature, high-viscosity biofilms. We propose a streamer formation mechanism by sudden partial detachment, as opposed to continuous elongation as observed in other microfluidic studies. Additionally, streamer formation occurred in straight microchannels, as opposed to serpentine or pseudo-porous channels, as previously reported.

  18. Video demystified

    CERN Document Server

    Jack, Keith

    2004-01-01

    This international bestseller and essential reference is the "bible" for digital video engineers and programmers worldwide. This is by far the most informative analog and digital video reference available, includes the hottest new trends and cutting-edge developments in the field. Video Demystified, Fourth Edition is a "one stop" reference guide for the various digital video technologies. The fourth edition is completely updated with all new chapters on MPEG-4, H.264, SDTV/HDTV, ATSC/DVB, and Streaming Video (Video over DSL, Ethernet, etc.), as well as discussions of the latest standards throughout. The accompanying CD-ROM is updated to include a unique set of video test files in the newest formats. *This essential reference is the "bible" for digital video engineers and programmers worldwide *Contains all new chapters on MPEG-4, H.264, SDTV/HDTV, ATSC/DVB, and Streaming Video *Completely revised with all the latest and most up-to-date industry standards.

  19. Real-time video streaming of sonographic clips using domestic internet networks and free videoconferencing software.

    Science.gov (United States)

    Liteplo, Andrew S; Noble, Vicki E; Attwood, Ben H C

    2011-11-01

    As the use of point-of-care sonography spreads, so too does the need for remote expert over-reading via telesonogrpahy. We sought to assess the feasibility of using familiar, widespread, and cost-effective existent technology to allow remote over-reading of sonograms in real time and to compare 4 different methods of transmission and communication for both the feasibility of transmission and image quality. Sonographic video clips were transmitted using 2 different connections (WiFi and 3G) and via 2 different videoconferencing modalities (iChat [Apple Inc, Cupertino, CA] and Skype [Skype Software Sàrl, Luxembourg]), for a total of 4 different permutations. The clips were received at a remote location and recorded and then scored by expert reviewers for image quality, resolution, and detail. Wireless transmission of sonographic clips was feasible in all cases when WiFi was used and when Skype was used over a 3G connection. Images transmitted via a WiFi connection were statistically superior to those transmitted via 3G in all parameters of quality (average P = .031), and those sent by iChat were superior to those sent by Skype but not statistically so (average P = .057). Wireless transmission of sonographic video clips using inexpensive hardware, free videoconferencing software, and domestic Internet networks is feasible with retention of image quality sufficient for interpretation. WiFi transmission results in greater image quality than transmission by a 3G network.

  20. Risk-aware scheduling for multi-user video streaming over wireless multi-hop networks

    Science.gov (United States)

    Shiang, Hsien-Po; van der Schaar, Mihaela

    2008-01-01

    To cope with the time-varying network conditions, various error-protection and channel adaptation strategies have been proposed at different layers of the protocol stack. However, these cross-layer strategies can be efficiently optimized only if they act on accurate information about the network conditions and hence, are able to timely adapt to network changes. We analyze the impact of such information feedback on the video quality performances of the collaborative multimedia users sharing the same multi-hop wireless infrastructure. Based on the information feedback, we can estimate the risk that packets from different priority and deadline classes will not arrive at their destination before their decoding deadline. Subsequently, cross-layer optimization strategies such as packet scheduling, retransmission (due to transmission error) limit are adapted to jointly consider the estimated risk as well as the impact in terms of distortion of not receiving different priority packets. Our results quantify the risk estimation and its benefit in different network conditions and for various video applications with different delay constraints.

  1. The roles of vocal and visual interactions in social learning zebra finches: A video playback experiment.

    Science.gov (United States)

    Guillette, Lauren M; Healy, Susan D

    2017-06-01

    The transmission of information from an experienced demonstrator to a naïve observer often depends on characteristics of the demonstrator, such as familiarity, success or dominance status. Whether or not the demonstrator pays attention to and/or interacts with the observer may also affect social information acquisition or use by the observer. Here we used a video-demonstrator paradigm first to test whether video demonstrators have the same effect as using live demonstrators in zebra finches, and second, to test the importance of visual and vocal interactions between the demonstrator and observer on social information use by the observer. We found that female zebra finches copied novel food choices of male demonstrators they saw via live-streaming video while they did not consistently copy from the demonstrators when they were seen in playbacks of the same videos. Although naive observers copied in the absence of vocalizations by the demonstrator, as they copied from playback of videos with the sound off, females did not copy where there was a mis-match between the visual information provided by the video and vocal information from a live male that was out of sight. Taken together these results suggest that video demonstration is a useful methodology for testing social information transfer, at least in a foraging context, but more importantly, that social information use varies according to the vocal interactions, or lack thereof, between the observer and the demonstrator. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  2. An Innovative Streaming Video System With a Point-of-View Head Camera Transmission of Surgeries to Smartphones and Tablets: An Educational Utility.

    Science.gov (United States)

    Chaves, Rafael Oliveira; de Oliveira, Pedro Armando Valente; Rocha, Luciano Chaves; David, Joacy Pedro Franco; Ferreira, Sanmari Costa; Santos, Alex de Assis Santos Dos; Melo, Rômulo Müller Dos Santos; Yasojima, Edson Yuzur; Brito, Marcus Vinicius Henriques

    2017-10-01

    In order to engage medical students and residents from public health centers to utilize the telemedicine features of surgery on their own smartphones and tablets as an educational tool, an innovative streaming system was developed with the purpose of streaming live footage from open surgeries to smartphones and tablets, allowing the visualization of the surgical field from the surgeon's perspective. The current study aims to describe the results of an evaluation on level 1 of Kirkpatrick's Model for Evaluation of the streaming system usage during gynecological surgeries, based on the perception of medical students and gynecology residents. Consisted of a live video streaming (from the surgeon's point of view) of gynecological surgeries for smartphones and tablets, one for each volunteer. The volunteers were able to connect to the local wireless network, created by the streaming system, through an access password and watch the video transmission on a web browser on their smartphones. Then, they answered a Likert-type questionnaire containing 14 items about the educational applicability of the streaming system, as well as comparing it to watching an in loco procedure. This study is formally approved by the local ethics commission (Certificate No. 53175915.7.0000.5171/2016). Twenty-one volunteers participated, totalizing 294 items answered, in which 94.2% were in agreement with the items affirmative, 4.1% were neutral, and only 1.7% answers corresponded to negative impressions. Cronbach's α was .82, which represents a good reliability level. Spearman's coefficients were highly significant in 4 comparisons and moderately significant in the other 20 comparisons. This study presents a local streaming video system of live surgeries to smartphones and tablets and shows its educational utility, low cost, and simple usage, which offers convenience and satisfactory image resolution, thus being potentially applicable in surgical teaching.

  3. Video as Text of Teaching: Toward More Deliberate Literacy Field Experience Supervision

    Science.gov (United States)

    Gelfuso, Andrea; Dennis, Danielle V.

    2017-01-01

    In this article, we theoretically explore how the deliberate use of video during literacy field experiences creates a text that can be read by triad members and can ameliorate the problem of relying on memory to engage in reflective conversations about literacy teaching and learning. The use of video, tools, and interactions with knowledgeable…

  4. ARBITER: Adaptive rate-based intelligent HTTP streaming algorithm

    OpenAIRE

    Zahran, Ahmed H.; Sreenan, Cormac J.

    2016-01-01

    Dynamic Adaptive streaming over HTTP (DASH) is widely used by content providers for video delivery and dominates traffic on cellular networks. The inherent variability in both video bitrate and network bandwidth negatively impacts the user Quality of Experience (QoE), motivating the design of better DASH-compliant adaptation algorithms. In this paper we present ARBITER, a novel streaming adaptation algorithm that explicitly integrates the variations in both video and network dynamics in its a...

  5. Students' Experiences of Ability-Based Streaming in Vocational Education

    Science.gov (United States)

    Tanggaard, Lene; Nielsen, Klaus; Jørgensen, Christian Helms

    2015-01-01

    Purpose: Since 2007, it has been mandatory for all vocational schools in Denmark to assess the prior qualifications of all students when they begin at the school and to use this assessment to divide students into different ability-based courses (streaming) with the aim of increasing the retention of students. The purpose of this paper is to…

  6. 4K Video Traffic Prediction using Seasonal Autoregressive Modeling

    Directory of Open Access Journals (Sweden)

    D. R. Marković

    2017-06-01

    Full Text Available From the perspective of average viewer, high definition video streams such as HD (High Definition and UHD (Ultra HD are increasing their internet presence year over year. This is not surprising, having in mind expansion of HD streaming services, such as YouTube, Netflix etc. Therefore, high definition video streams are starting to challenge network resource allocation with their bandwidth requirements and statistical characteristics. Need for analysis and modeling of this demanding video traffic has essential importance for better quality of service and experience support. In this paper we use an easy-to-apply statistical model for prediction of 4K video traffic. Namely, seasonal autoregressive modeling is applied in prediction of 4K video traffic, encoded with HEVC (High Efficiency Video Coding. Analysis and modeling were performed within R programming environment using over 17.000 high definition video frames. It is shown that the proposed methodology provides good accuracy in high definition video traffic modeling.

  7. Quality of pharmaceutical care at the pharmacy counter: patients’ experiences versus video observation.

    NARCIS (Netherlands)

    Koster, E.S.; Blom, L.; Overbeeke, M.R.; Philbert, D.; Vervloet, M.; Koopman, L.; Dijk, L. van

    2016-01-01

    Introduction: Consumer Quality Index questionnaires are used to assess quality of care from patients’ experiences. Objective: To provide insight into the agreement about quality of pharmaceutical care, measured both by a patient questionnaire and video observations. Methods: Pharmaceutical

  8. Study of the effects of video content on quality of experience

    Science.gov (United States)

    Paudyal, Pradip; Battisti, Federica; Carli, Marco

    2015-01-01

    In this article the effects of video content on Quality of Experience (QoE) have been presented. Delivery of the video content with high level of QoE from bandwidth-limited and error-prone network is of crucial importance for the service providers. Therefore, it is of fundamental importance to analyse the impact of the network impairments and video content on perceived quality during the QoE metric design. The major contributions of the article are in the study of i)the impact of network impairments together with video content, ii) impact of the video content and ii) the impact of video content related parameters: spatial-temporal perceptual information, video content, and frame size on QoE has been presented. The results show that when the impact of impairments on perceived quality is low, the quality is significantly influenced by video content, and video content itself also has a significant impact on QoE. Finally, the results strengthen the need for new parameter characterization, for better QoE metric design.

  9. Video and literacy: the Nigerian experience | Adeyemi | Lwati: A ...

    African Journals Online (AJOL)

    Since the emergence of the video technology in the eighties as a popular art form in Nigeria its artistic and technical potentials as a means of radically transforming the literacy and language development of the society have not been fully explored. One major reason for this shortcoming is the myopic and pedestrian ...

  10. Conference Video for Booth at SAE World Congress Experience Conference

    Science.gov (United States)

    Harkey, Ann Marie

    2017-01-01

    Contents: Publicly released videos on technology transfer items available for licensing from NASA. Includes; Powder Handling Device for Analytical Instruments (Ames); 2. Fiber Optic Shape Sensing (FOSS) (Armstrong); 3. Robo-Glove (Johnson); 4. Modular Robotic Vehicle (Johnson); 5. Battery Management System (Johnson); 6. Active Response Gravity Offload System (ARGOS) (Johnson); 7. Contaminant Resistant Coatings for Extreme Environments (Langley); 8. Molecular Adsorber Coating (MAC) (Goddard); 9. Ultrasonic Stir Welding (Marshall). Also includes scenes from the International Space Station.

  11. The impact of video technology on learning: A cooking skills experiment.

    Science.gov (United States)

    Surgenor, Dawn; Hollywood, Lynsey; Furey, Sinéad; Lavelle, Fiona; McGowan, Laura; Spence, Michelle; Raats, Monique; McCloat, Amanda; Mooney, Elaine; Caraher, Martin; Dean, Moira

    2017-07-01

    This study examines the role of video technology in the development of cooking skills. The study explored the views of 141 female participants on whether video technology can promote confidence in learning new cooking skills to assist in meal preparation. Prior to each focus group participants took part in a cooking experiment to assess the most effective method of learning for low-skilled cooks across four experimental conditions (recipe card only; recipe card plus video demonstration; recipe card plus video demonstration conducted in segmented stages; and recipe card plus video demonstration whereby participants freely accessed video demonstrations as and when needed). Focus group findings revealed that video technology was perceived to assist learning in the cooking process in the following ways: (1) improved comprehension of the cooking process; (2) real-time reassurance in the cooking process; (3) assisting the acquisition of new cooking skills; and (4) enhancing the enjoyment of the cooking process. These findings display the potential for video technology to promote motivation and confidence as well as enhancing cooking skills among low-skilled individuals wishing to cook from scratch using fresh ingredients. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Attention and Distraction: On the Aesthetic Experience of Video Installation Art

    Directory of Open Access Journals (Sweden)

    Petersen, Anne Ring

    2010-10-01

    Full Text Available This article aims to examine the interrelationship between attention and distraction in the reception of video installation art, a genre which is commonly associated with "immersion" and an intensified feeling of presence in the discourses on new media art and installation art. This tends to veil the fact that the behaviour of many visitors is characterised by a certain restlessness and distraction. The article suggests that, in contradistinction to traditional disciplines of art like painting and sculpture, video installations seem to stimulate a "reception in distraction" (Walter Benjamin that is at odds with the ideal of a reception in concentration that governs the institutions of fine art as well as aesthetic theory. It intends to demonstrate how the experience of video installation art can only be understood by recognising that the close connections between, on the one hand, video art and, on the other hand, the cultural formations of television, film and computers have fundamentally re-configured "aesthetic experience."

  13. Psychogenic non-epileptic seizures: our video-EEG experience.

    Science.gov (United States)

    Nežádal, Tomáš; Hovorka, Jiří; Herman, Erik; Němcová, Iveta; Bajaček, Michal; Stichová, Eva

    2011-09-01

    The aim of our study was to assess the number of psychogenic non-epileptic seizures (PNES) in our patients with a refractory seizure disorder, to determine the 'typical' PNES semiology using video-EEG monitoring and describe other PNES parameters. We evaluated prospectively 596 patients with pharmacoresistant seizures. All these patients underwent continuous video-EEG monitoring. In consenting patients, we used suggestive seizure provocation. We assessed seizure semiology, interictal EEG, brain MRI, psychiatric co-morbidities, personality profiles, and seizure outcome. In the sample of 596 monitored patients, we detected 111 (19.3%) patients with PNES. Of the 111 patients with PNES, 86.5% had spontaneous and 76.5% had provoked seizures. The five most typical symptoms were: initially closed eyelids (67.6%), rapid tremor (47.7%), asynchronous limb movement (37.8%), preictal pseudosleep (33.3%), and side-to-side head movement (32.4%). Interictal EEG was rated as abnormal in 46.2% and with epileptiform abnormality in 9%. Brain MRI was abnormal in 32 (28.8%) patients. Personality disorders (46.8%), anxiety (39.6%), and depression (12.6%) were the most frequent additional psychiatric co-morbidities. PNES outcome after at least 2 years is reported; 22.5% patients was seizure-free; one-third had markedly reduced seizure frequency. We have not seen any negative impact of the provocative testing on the seizure outcome. Video-EEG monitoring with suggestive seizure provocation supported by clinical psychiatric and psychological evaluation significantly contributes to the correct PNES diagnosis, while interictal EEG and brain MRI are frequently abnormal. Symptoms typical for PNES, as opposed to epileptic seizures, could be distinguished.

  14. Video games, cinema, Bazin, and the myth of simulated lived experience

    Directory of Open Access Journals (Sweden)

    Mark J.P. Wolf

    2015-09-01

    Full Text Available Video games theory has advanced far enough that we can use it to reevaluate film theory as a  result, en route to broader, transmedial theorizing. This essay looks particularly at how video  games can be seen as participating in and advancing Andre Bazin’s “Myth of Total Cinema”, and  perhaps recontextualzing it as the Myth of Simulated Lived Experience.

  15. A Framework of Reference for Evaluating User Experience When Using High Definition Video to Video to Facilitate Public Services

    OpenAIRE

    Molnar, Andreea; Weerakkody, Vishanth; El-Haddadeh, Ramzi; Lee, Habin; Irani, Zahir

    2013-01-01

    Part 5: IT in the Public Sector; International audience; This paper proposes the use of high definition video to video as a means to facilitate the adoption of public services. High definition video can be delivered over the public Internet infrastructure by using a Right of Way platform that guarantees no interference from unwanted traffic. In this paper, we discuss the benefits of using high definition video to video communication in the public sector to facilitate services such as health, ...

  16. Technology consumption and cognitive control: Contrasting action video game experience with media multitasking.

    Science.gov (United States)

    Cardoso-Leite, Pedro; Kludt, Rachel; Vignola, Gianluca; Ma, Wei Ji; Green, C Shawn; Bavelier, Daphne

    2016-01-01

    Technology has the potential to impact cognition in many ways. Here we contrast two forms of technology usage: (1) media multitasking (i.e., the simultaneous consumption of multiple streams of media, such a texting while watching TV) and (2) playing action video games (a particular subtype of video games). Previous work has outlined an association between high levels of media multitasking and specific deficits in handling distracting information, whereas playing action video games has been associated with enhanced attentional control. Because these two factors are linked with reasonably opposing effects, failing to take them jointly into account may result in inappropriate conclusions as to the impacts of technology use on attention. Across four tasks (AX-continuous performance, N-back, task-switching, and filter tasks), testing different aspects of attention and cognition, we showed that heavy media multitaskers perform worse than light media multitaskers. Contrary to previous reports, though, the performance deficit was not specifically tied to distractors, but was instead more global in nature. Interestingly, participants with intermediate levels of media multitasking sometimes performed better than both light and heavy media multitaskers, suggesting that the effects of increasing media multitasking are not monotonic. Action video game players, as expected, outperformed non-video-game players on all tasks. However, surprisingly, this was true only for participants with intermediate levels of media multitasking, suggesting that playing action video games does not protect against the deleterious effect of heavy media multitasking. Taken together, these findings show that media consumption can have complex and counterintuitive effects on attentional control.

  17. XbD Video 2, Taxonomy of Experience (ToE) [Online

    DEFF Research Database (Denmark)

    2013-01-01

    This is the second video in the Experience-based Designing series: It describes the Taxonomy of Experience, a structural way of looking at human experiences of almost any kind.This hierarchical model is useful to researchers and decision makers as a general method or tool for guiding the collection......, processing and categorisation of field data about an everyday experience. Researchers using this model often referred to the process as 'doing a ToE'...

  18. VQone MATLAB toolbox: A graphical experiment builder for image and video quality evaluations: VQone MATLAB toolbox.

    Science.gov (United States)

    Nuutinen, Mikko; Virtanen, Toni; Rummukainen, Olli; Häkkinen, Jukka

    2016-03-01

    This article presents VQone, a graphical experiment builder, written as a MATLAB toolbox, developed for image and video quality ratings. VQone contains the main elements needed for the subjective image and video quality rating process. This includes building and conducting experiments and data analysis. All functions can be controlled through graphical user interfaces. The experiment builder includes many standardized image and video quality rating methods. Moreover, it enables the creation of new methods or modified versions from standard methods. VQone is distributed free of charge under the terms of the GNU general public license and allows code modifications to be made so that the program's functions can be adjusted according to a user's requirements. VQone is available for download from the project page (http://www.helsinki.fi/psychology/groups/visualcognition/).

  19. [The Questionnaire of Experiences Associated with Video games (CERV): an instrument to detect the problematic use of video games in Spanish adolescents].

    Science.gov (United States)

    Chamarro, Andres; Carbonell, Xavier; Manresa, Josep Maria; Munoz-Miralles, Raquel; Ortega-Gonzalez, Raquel; Lopez-Morron, M Rosa; Batalla-Martinez, Carme; Toran-Monserrat, Pere

    2014-01-01

    The aim of this study is to validate the Video Game-Related Experiences Questionnaire (CERV in Spanish). The questionnaire consists of 17 items, developed from the CERI (Internet-Related Experiences Questionnaire - Beranuy and cols.), and assesses the problematic use of non-massive video games. It was validated for adolescents in Compulsory Secondary Education. To validate the questionnaire, a confirmatory factor analysis (CFA) and an internal consistency analysis were carried out. The factor structure shows two factors: (a) Psychological dependence and use for evasion; and (b) Negative consequences of using video games. Two cut-off points were established for people with no problems in their use of video games (NP), with potential problems in their use of video games (PP), and with serious problems in their use of video games (SP). Results show that there is higher prevalence among males and that problematic use decreases with age. The CERV seems to be a good instrument for the screening of adolescents with difficulties deriving from video game use. Further research should relate problematic video game use with difficulties in other life domains, such as the academic field.

  20. Integrating virtual reality video games into practice: clinicians' experiences.

    Science.gov (United States)

    Levac, Danielle E; Miller, Patricia A

    2013-10-01

    The Nintendo Wii is a popular virtual reality (VR) video gaming system in rehabilitation practice and research. As evidence emerges related to its effectiveness as a physical therapy training method, clinicians require information about the pragmatics of its use in practice. The purpose of this descriptive qualitative study is to explore observations and insights from a sample of physical therapists (PTs) working with children with acquired brain injury regarding practical implications of using the Wii as a physical therapy intervention. Six PTs employed at a children's rehabilitation center participated in semi-structured interviews, which were transcribed and analyzed using content analysis. Two themes summarize the practical implications of Wii use: 1) technology meets clinical practice; and 2) onus is on the therapist. Therapists described both beneficial and challenging implications arising from the intersection of technology and practice, and reported the personal commitment required to orient oneself to the gaming system and capably implement this intervention. Findings include issues that may be relevant to professional development in a broader rehabilitation context, including suggestions for the content of educational initiatives and the need for institutional support from managers in the form of physical resources for VR implementation.

  1. Geoblocking and global video culture.

    NARCIS (Netherlands)

    Lobato, Ramon; Meese, James; Rasch, Mirjam

    How do global audiences use streaming platforms like YouTube, Netflix and iPlayer? How does the experience of digital video change according to location? What strategies do people use to access out-of-region content? What are the commercial and governmental motivations behind geoblocking?

  2. Real-Time Strategy Video Game Experience and Visual Perceptual Learning.

    Science.gov (United States)

    Kim, Yong-Hwan; Kang, Dong-Wha; Kim, Dongho; Kim, Hye-Jin; Sasaki, Yuka; Watanabe, Takeo

    2015-07-22

    Visual perceptual learning (VPL) is defined as long-term improvement in performance on a visual-perception task after visual experiences or training. Early studies have found that VPL is highly specific for the trained feature and location, suggesting that VPL is associated with changes in the early visual cortex. However, the generality of visual skills enhancement attributable to action video-game experience suggests that VPL can result from improvement in higher cognitive skills. If so, experience in real-time strategy (RTS) video-game play, which may heavily involve cognitive skills, may also facilitate VPL. To test this hypothesis, we compared VPL between RTS video-game players (VGPs) and non-VGPs (NVGPs) and elucidated underlying structural and functional neural mechanisms. Healthy young human subjects underwent six training sessions on a texture discrimination task. Diffusion-tensor and functional magnetic resonance imaging were performed before and after training. VGPs performed better than NVGPs in the early phase of training. White-matter connectivity between the right external capsule and visual cortex and neuronal activity in the right inferior frontal gyrus (IFG) and anterior cingulate cortex (ACC) were greater in VGPs than NVGPs and were significantly correlated with RTS video-game experience. In both VGPs and NVGPs, there was task-related neuronal activity in the right IFG, ACC, and striatum, which was strengthened after training. These results indicate that RTS video-game experience, associated with changes in higher-order cognitive functions and connectivity between visual and cognitive areas, facilitates VPL in early phases of training. The results support the hypothesis that VPL can occur without involvement of only visual areas. Significance statement: Although early studies found that visual perceptual learning (VPL) is associated with involvement of the visual cortex, generality of visual skills enhancement by action video-game experience

  3. Student Activity and Profile Datasets from an Online Video-Based Collaborative Learning Experience

    Science.gov (United States)

    Martín, Estefanía; Gértrudix, Manuel; Urquiza-Fuentes, Jaime; Haya, Pablo A.

    2015-01-01

    This paper describes two datasets extracted from a video-based educational experience using a social and collaborative platform. The length of the trial was 3 months. It involved 111 students from two different courses. Twenty-nine came from Computer Engineering (CE) course and 82 from Media and Communication (M&C) course. They were organised…

  4. Movement-based Sports Video Games: Investigating Motivation and Gaming Experience

    NARCIS (Netherlands)

    Reidsma, Dennis; Reidsma, D.; Pasch, Marco; Bianchi-Berthouze, Nadia; Nijholt, A.; Nijholt, Antinus; van Dijk, Elisabeth M.A.G.

    2009-01-01

    Video game consoles that enable gamers to use active body movements are becoming increasingly popular. Yet, little is known about the influence of movement on how gamers experience such games. This study takes an exploratory approach, using different data collection methods. A theory about the

  5. ACM International Conference on Interactive Experiences for Television and Online Video (ACM TVX 2014)

    NARCIS (Netherlands)

    P.S. Cesar Garcia (Pablo Santiago); M. Obrist (Marianna); E.M. Churchill; T. Bartindale

    2014-01-01

    htmlabstractThis article describes the new ACM International Conference on Interactive Experiences for Television and Online Video (ACM TVX) and provides a recap of the 1st ACM TVX, which took place in Newcastle Upon Tyne, UK, from 25-27 June 2014.

  6. Implementation and Analysis of Real-Time Streaming Protocols.

    Science.gov (United States)

    Santos-González, Iván; Rivero-García, Alexandra; Molina-Gil, Jezabel; Caballero-Gil, Pino

    2017-04-12

    Communication media have become the primary way of interaction thanks to the discovery and innovation of many new technologies. One of the most widely used communication systems today is video streaming, which is constantly evolving. Such communications are a good alternative to face-to-face meetings, and are therefore very useful for coping with many problems caused by distance. However, they suffer from different issues such as bandwidth limitation, network congestion, energy efficiency, cost, reliability and connectivity. Hence, the quality of service and the quality of experience are considered the two most important issues for this type of communication. This work presents a complete comparative study of two of the most used protocols of video streaming, Real Time Streaming Protocol (RTSP) and the Web Real-Time Communication (WebRTC). In addition, this paper proposes two new mobile applications that implement those protocols in Android whose objective is to know how they are influenced by the aspects that most affect the streaming quality of service, which are the connection establishment time and the stream reception time. The new video streaming applications are also compared with the most popular video streaming applications for Android, and the experimental results of the analysis show that the developed WebRTC implementation improves the performance of the most popular video streaming applications with respect to the stream packet delay.

  7. Cognitive Modeling of Video Game Player User Experience

    Science.gov (United States)

    Bohil, Corey J.; Biocca, Frank A.

    2010-01-01

    This paper argues for the use of cognitive modeling to gain a detailed and dynamic look into user experience during game play. Applying cognitive models to game play data can help researchers understand a player's attentional focus, memory status, learning state, and decision strategies (among other things) as these cognitive processes occurred throughout game play. This is a stark contrast to the common approach of trying to assess the long-term impact of games on cognitive functioning after game play has ended. We describe what cognitive models are, what they can be used for and how game researchers could benefit by adopting these methods. We also provide details of a single model - based on decision field theory - that has been successfUlly applied to data sets from memory, perception, and decision making experiments, and has recently found application in real world scenarios. We examine possibilities for applying this model to game-play data.

  8. Students' Learning Experiences from Didactic Teaching Sessions Including Patient Case Examples as Either Text or Video

    DEFF Research Database (Denmark)

    Pedersen, Kamilla; Moeller, Martin Holdgaard; Paltved, Charlotte

    2017-01-01

    OBJECTIVES: The aim of this study was to explore medical students' learning experiences from the didactic teaching formats using either text-based patient cases or video-based patient cases with similar content. The authors explored how the two different patient case formats influenced students....... Students taught with video-based patient cases, in contrast, often referred to the patient cases when highlighting new insights, including the importance of patient perspectives when communicating with patients. CONCLUSION: The format of patient cases included in teaching may have a substantial impact...

  9. Estimating Economic Value of Stream Restoration for Urban Watershed Using Choice Experiments

    Science.gov (United States)

    Oh, J.; Lee, K. S.; Yoo, J.; Kong, K.; Seoul National University; Chungbuk National University

    2010-12-01

    Since the Yangjaecheon and the Cheonggyecheon project by Seoul city is recognized as starting point of stream restoration project in Korea, many streams having a straight corridor and covered by concrete in an urban watershed have been projected to restore its natural appearance. In some of local autonomous entities the objective of the stream restoration project only deals with improvements in a function of environment which is recreation and amenity for a citizen. Therefore, this study uses the choice experiments based on a citizen’s preference to estimate economic benefits from stream restoration in an urban watershed. The study area is the downstream section (4.5 km from outlet) of the Mokgamcheon, which had been implementing the restoration project. To apply the choice experiments, 5 attributes are chosen as status-quo of the study area. In an attribute of flood control, Potential Flood Damage (PFD) is estimated. A result of comparison between a maintenance flow and a flow duration curve using PCSWMM model is used to achieve an attribute of water utilization. In an attribute of environment, Assessment of Stream Naturalness considering Physical, Biological, Chemical factors (ASNPBC) is applied to get physical stream appearance, and biological, chemical water quality and Use Index of Stream space for Citizen (UISC) is used to survey how facilities for rest, exercise, amenity and view are distributed in the stream space. The results of an assessment for all attributes are estimated to be the 3rd grade. All the attributes introduced above have 4 level grading systems. The attribute described willingness to pay has 3 levels estimated through a survey from a specialist group. An orthogonal plan is used to avoid collinearity between levels of attributes, and a preliminary survey, which is questioned to students and citizens living in the study area is built to modify survey errors and obtain reasonable results. The population of the main survey is citizens living

  10. Watermarking textures in video games

    Science.gov (United States)

    Liu, Huajian; Berchtold, Waldemar; Schäfer, Marcel; Lieb, Patrick; Steinebach, Martin

    2014-02-01

    Digital watermarking is a promising solution to video game piracy. In this paper, based on the analysis of special challenges and requirements in terms of watermarking textures in video games, a novel watermarking scheme for DDS textures in video games is proposed. To meet the performance requirements in video game applications, the proposed algorithm embeds the watermark message directly in the compressed stream in DDS files and can be straightforwardly applied in watermark container technique for real-time embedding. Furthermore, the embedding approach achieves high watermark payload to handle collusion secure fingerprinting codes with extreme length. Hence, the scheme is resistant to collusion attacks, which is indispensable in video game applications. The proposed scheme is evaluated in aspects of transparency, robustness, security and performance. Especially, in addition to classical objective evaluation, the visual quality and playing experience of watermarked games is assessed subjectively in game playing.

  11. Newton’s Cradle Experiment Using Video Tracking Analysis with Multiple Representation Approach

    Science.gov (United States)

    Anissofira, A.; Latief, F. D. E.; Kholida, L.; Sinaga, P.

    2017-09-01

    This paper reports a Physics lesson using video tracking analysis applied in Newton’s Cradle experiment to train student’s multiple representation skill. This study involved 30 science high school students from class XI. In this case, Tracker software was used to verify energy conservation law, with help from data result such as graphs and tables. Newton’s Cradle is commonly used to demonstrate the law of energy and momentum conservation. It consists of swinging spherical bobs which transfers energy from one to another by means of elastic collisions. From the video analysis, it is found that there is a difference in the velocity of the two bobs of opposite ends. Furthermore, investigation of what might cause it to happen can be done by observing and analysing the recorded video. This paper discusses students’ response and teacher’s reflection after using Tracker video analysis software in the Physics lesson. Since Tracker has the ability to provide us with multiple means of data representation way, we conclude that this method could be a good alternative solution and might also be considered better than performing a hands-on experiment activity in which not every school have suitable laboratory equipment.

  12. Development of a cell phone-based video streaming system for persons with early stage Alzheimer's disease.

    Science.gov (United States)

    Donnelly, Mark P; Nugent, Chris D; Craig, David; Passmore, Peter; Mulvenna, Maurice

    2008-01-01

    The current paper presents details regarding the early developments of a memory prompt solution for persons with early dementia. Using everyday technology, in the form of a cell-phone, video reminders are delivered to assist with daily activities. The proposed CPVS system will permit carers to record and schedule video reminders remotely using a standard personal computer and web cam. It is the aim of the three year project that through the frequent delivery of helpful video reminders that a 'virtual carer' will be present with the person with dementia at all times. The first prototype of the system has been fully implemented with the first field trial scheduled to take place in May 2008. Initially, only three patient carer dyads will be involved, however, the second field trial aims to involve 30 dyads in the study. Details of the first prototype and the methods of evaluation are presented herein.

  13. Brugeroplevelse af streaming-tjenesten Netflix

    OpenAIRE

    Leifer, Anders; Frydendahl, Erik Pouret; Nedergaard, Mads Kresten

    2014-01-01

    This paper aims to describe and understand the use of the video streaming service Netflix among younger single females, with the further aim to understand the success of streaming in general and Netflix’s offer as an experience economy based offering in particular. After introducing Netflix through a review of its history and its competitive environment, and establishing the epistemological and methodological framework, the paper presents its empiric part, a qualitative semi-structured int...

  14. Quality of pharmaceutical care at the pharmacy counter: patients’ experiences versus video observation

    Directory of Open Access Journals (Sweden)

    Koster ES

    2016-03-01

    Full Text Available Ellen S Koster,1 Lyda Blom,1 Marloes R Overbeeke,1 Daphne Philbert,1 Marcia Vervloet,2 Laura Koopman,2,3 Liset van Dijk2 1Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht University, the Netherlands; 2Netherlands Institute of Health Services Research (NIVEL, Utrecht, the Netherlands; 3National Health Care Institute, Diemen, the Netherlands Introduction: Consumer Quality Index questionnaires are used to assess quality of care from patients’ experiences.Objective: To provide insight into the agreement about quality of pharmaceutical care, measured both by a patient questionnaire and video observations.Methods: Pharmaceutical encounters in four pharmacies were video-recorded. Patients completed a questionnaire based upon the Consumer Quality Index Pharmaceutical Care after the encounter containing questions about patients’ experiences regarding information provision, medication counseling, and pharmacy staff’s communication style. An observation protocol was used to code the recorded encounters. Agreement between video observation and patients’ experiences was calculated.Results: In total, 109 encounters were included for analysis. For the domains “medication counseling” and “communication style”, agreement between patients’ experiences and observations was very high (>90%. Less agreement (45% was found for “information provision”, which was rated more positive by patients compared to the observations, especially for the topic, encouragement of patients’ questioning behavior.Conclusion: A questionnaire is useful to assess the quality of medication counseling and pharmacy staff’s communication style, but might be less suitable to evaluate information provision and pharmacy staff’s encouragement of patients’ questioning behavior. Although patients may believe that they have received all necessary information to use their new medicine, some information on specific instructions was not addressed during

  15. Teens, Video Games, and Civics: Teens' Gaming Experiences Are Diverse and Include Significant Social Interaction and Civic Engagement

    Science.gov (United States)

    Lenhart, Amanda; Kahne, Joseph; Middaugh, Ellen; Macgill, Alexandra Rankin; Evans, Chris; Vitak, Jessica

    2008-01-01

    Video games provide a diverse set of experiences and related activities and are part of the lives of almost all teens in America. To date, most video game research has focused on how games impact academic and social outcomes (particularly aggression). There has also been some exploration of the relationship between games and civic outcomes, but as…

  16. The role of background music in the experience of watching YouTube videos about death and dying.

    OpenAIRE

    Pentaris, Panagiotis; Yerosimou, Maria

    2015-01-01

    YouTube is the largest video-sharing site live at the moment. It has been used to communicate a vast array of information, while it allows for user-generated content. This paper will focus on YouTube videos that communicate death, and, in particular, will present findings from a preliminary study undertaken by the authors considering the role that background music plays in these videos. Specifically, this study explores the experiences of the viewers of death-related YouTube videos with and w...

  17. Immersive video

    Science.gov (United States)

    Moezzi, Saied; Katkere, Arun L.; Jain, Ramesh C.

    1996-03-01

    Interactive video and television viewers should have the power to control their viewing position. To make this a reality, we introduce the concept of Immersive Video, which employs computer vision and computer graphics technologies to provide remote users a sense of complete immersion when viewing an event. Immersive Video uses multiple videos of an event, captured from different perspectives, to generate a full 3D digital video of that event. That is accomplished by assimilating important information from each video stream into a comprehensive, dynamic, 3D model of the environment. Using this 3D digital video, interactive viewers can then move around the remote environment and observe the events taking place from any desired perspective. Our Immersive Video System currently provides interactive viewing and `walkthrus' of staged karate demonstrations, basketball games, dance performances, and typical campus scenes. In its full realization, Immersive Video will be a paradigm shift in visual communication which will revolutionize television and video media, and become an integral part of future telepresence and virtual reality systems.

  18. Video of Miscible Fluid Experiment Conducted on NASA Low Gravity Airplane

    Science.gov (United States)

    2003-01-01

    This is a video of dyed water being injected into glycerin in a 2.2 centimeter (cm) diameter test tube. The experiment was conducted on the KC-135 aircraft, a NASA plane that creates microgravity and 2g conditions as it maneuvers through multiple parabolas. The water is less dense and so it rises to the top of the glycerin. The goal of the experiment was to determine if a blob of a miscible fluid would spontaneously become spherical in a microgravity environment.

  19. The role of background music in the experience of watching YouTube videos about death and dying

    Directory of Open Access Journals (Sweden)

    Panagiotis Pentaris

    2015-12-01

    Full Text Available YouTube is the largest video sharing site live at the moment. It has been used to communicate a vast array of information, while it allows for user-generated content. This paper will focus on YouTube videos that communicate death, and in particular will present findings from a preliminary study undertaken by the authors considering the role that background music plays in these videos. Specifically, this study explores the experiences of the viewers of death-related YouTube videos with and without background music while it makes comparisons in relation to the impact that music has on the viewers’ emotional experiences. We conclude that background music elicits emotions and enhances feelings of sadness and sympathy in relation to the visual content of videos while recommendations for future research are made.

  20. An Algorithm of Extracting I-Frame in Compressed Video

    Directory of Open Access Journals (Sweden)

    Zhu Yaling

    2015-01-01

    Full Text Available The MPEG video data includes three types of frames, that is: I-frame, P-frame and B-frame. However, the I-frame records the main information of video data, the P-frame and the B-frame are just regarded as motion compensations of the I-frame. This paper presents the approach which analyzes the MPEG video stream in the compressed domain, and find out the key frame of MPEG video stream by extracting the I-frame. Experiments indicated that this method can be automatically realized in the compressed MPEG video and it will lay the foundation for the video processing in the future.

  1. Simulation and Preliminary Design of a Cold Stream Experiment on Omega EP

    Science.gov (United States)

    Coffing, Shane; Angulo, Adrianna; Trantham, Matt; Malamud, Guy; Kuranz, Carolyn; Drake, R. P.

    2017-10-01

    Galaxies form within dark matter halos, accreting gas that may clump and eventually form stars. Infalling matter gradually increases the density of the halo, and, if cooling is insufficient, rising pressure forms a shock that slows the infalling gas, reducing star formation. However, galaxies with sufficient cooling become prolific star formers. A recent theory suggests that so called ``stream fed galaxies'' are able to acquire steady streams of cold gas via galactic ``filaments'' that penetrate the halo. The cold, dense filament flowing into a hot, less dense environment is potentially Kelvin-Helmholtz unstable. This instability may hinder the ability of the stream to deliver gas deeply enough into the halo. To study this process, we have begun preliminary design of a well-scaled laser experiment on Omega EP. We present here early simulation results and the physics involved. This work is funded by the U.S. Department of Energy, through the NNSA-DS and SC-OFES Joint Program in High-Energy-Density Laboratory Plasmas, Grant Number DE-NA0002956, and the National Laser User Facility Program, Grant Number DE-NA0002719, and through the Laboratory for Laser Energetics, University of Rochester by the NNSA/OICF under Cooperative Agreement No. DE-NA0001944.

  2. Hybrid Peer-to-peer Streaming System for Mobile Peers with Transcoding

    Directory of Open Access Journals (Sweden)

    Shuai Zeng

    2015-08-01

    Full Text Available In this paper, we study in hybrid peer-to-peer (P2P streaming system, which includes fixed peers and mobile peers in the same network, and propose a flow rate allocation algorithm to optimize the streaming system. In the proposed algorithm, based on transcoding technique, we describe how to exchange original and transcoded data among video source server, fixed and mobile peers. The purpose of our algorithm is to reduce the bandwidth demand of video source server, while ensuring the flow rate of video data sending to any peer no less than its video coding rate. We compare the performance of P2P streaming system using our algorithm with traditional design in various situations in the simulation experiment, and test how much benefit the system can get from the new algorithm. The results show that, if the flow rate of video data is allocated appropriately, better performance of streaming system can be achieved.

  3. Nitrate removal in stream ecosystems measured by 15N addition experiments: Total uptake

    Science.gov (United States)

    Hall, R.O.; Tank, J.L.; Sobota, D.J.; Mulholland, P.J.; O'Brien, J. M.; Dodds, W.K.; Webster, J.R.; Valett, H.M.; Poole, G.C.; Peterson, B.J.; Meyer, J.L.; McDowell, W.H.; Johnson, S.L.; Hamilton, S.K.; Grimm, N. B.; Gregory, S.V.; Dahm, Clifford N.; Cooper, L.W.; Ashkenas, L.R.; Thomas, S.M.; Sheibley, R.W.; Potter, J.D.; Niederlehner, B.R.; Johnson, L.T.; Helton, A.M.; Crenshaw, C.M.; Burgin, A.J.; Bernot, M.J.; Beaulieu, J.J.; Arangob, C.P.

    2009-01-01

    We measured uptake length of 15NO-3 in 72 streams in eight regions across the United States and Puerto Rico to develop quantitative predictive models on controls of NO-3 uptake length. As part of the Lotic Intersite Nitrogen eXperiment II project, we chose nine streams in each region corresponding to natural (reference), suburban-urban, and agricultural land uses. Study streams spanned a range of human land use to maximize variation in NO-3 concentration, geomorphology, and metabolism. We tested a causal model predicting controls on NO-3 uptake length using structural equation modeling. The model included concomitant measurements of ecosystem metabolism, hydraulic parameters, and nitrogen concentration. We compared this structural equation model to multiple regression models which included additional biotic, catchment, and riparian variables. The structural equation model explained 79% of the variation in log uptake length (S Wtot). Uptake length increased with specific discharge (Q/w) and increasing NO-3 concentrations, showing a loss in removal efficiency in streams with high NO-3 concentration. Uptake lengths shortened with increasing gross primary production, suggesting autotrophic assimilation dominated NO-3 removal. The fraction of catchment area as agriculture and suburban-urban land use weakly predicted NO-3 uptake in bivariate regression, and did improve prediction in a set of multiple regression models. Adding land use to the structural equation model showed that land use indirectly affected NO-3 uptake lengths via directly increasing both gross primary production and NO-3 concentration. Gross primary production shortened SWtot, while increasing NO-3 lengthened SWtot resulting in no net effect of land use on NO- 3 removal. ?? 2009.

  4. The large-scale organization of "visual" streams emerges without visual experience.

    Science.gov (United States)

    Striem-Amit, Ella; Dakwar, Ornella; Reich, Lior; Amedi, Amir

    2012-07-01

    A key question in sensory perception is the role of experience in shaping the functional architecture of the sensory neural systems. Here we studied dependence on visual experience in shaping the most fundamental division of labor in vision, namely between the ventral "what" and the dorsal "where and how" processing streams. We scanned 11 fully congenitally blind (CB) and 9 sighted individuals performing location versus form identification tasks following brief training on a sensory substitution device used for artificial vision. We show that the dorsal/ventral visual pathway division of labor can be revealed in the adult CB when perceiving sounds that convey the relevant visual information. This suggests that the most important large-scale organization of the visual system into the 2 streams can develop even without any visual experience and can be attributed at least partially to innately determined constraints and later to cross-modal plasticity. These results support the view that the brain is organized into task-specific but sensory modality-independent operators.

  5. Video surveillance system based on MPEG-4

    Science.gov (United States)

    Ge, Jing; Zhang, Guoping; Yang, Zongkai

    2008-03-01

    Multimedia technology and networks protocol are the basic technology of the video surveillance system. A network remote video surveillance system based on MPEG-4 video coding standards is designed and implemented in this paper. The advantages of the MPEG-4 are analyzed in detail in the surveillance field, and then the real-time protocol and real-time control protocol (RTP/RTCP) are chosen as the networks transmission protocol. The whole system includes video coding control module, playing back module, network transmission module and network receiver module The scheme of management, control and storage about video data are discussed. The DirectShow technology is used to playback video data. The transmission scheme of digital video processing in networks, RTP packaging of MPEG-4 video stream is discussed. The receiver scheme of video date and mechanism of buffer are discussed. The most of the functions are archived by software, except that the video coding control module is achieved by hardware. The experiment results show that it provides good video quality and has the real-time performance. This system can be applied into wide fields.

  6. Kaiser Permanente Northern California: current experiences with internet, mobile, and video technologies.

    Science.gov (United States)

    Pearl, Robert

    2014-02-01

    The US health care system has been slow to adopt Internet, mobile, and video technologies, which have the capability to engage patients in their own care, increase patients' access to providers, and possibly improve the quality of care while reducing costs. Nevertheless, there are some pockets of progress, including Kaiser Permanente Northern California (KPNC). In 2008 KPNC implemented an inpatient and ambulatory care electronic health record system for its 3.4 million members and developed a suite of patient-friendly Internet, mobile, and video tools. KPNC has achieved many successes. For example, the number of virtual "visits" grew from 4.1 million in 2008 to an estimated 10.5 million in 2013. This article describes KPNC's experience with Internet, mobile, and video technologies and the obstacles faced by other health care providers interested in embracing them. The obstacles include the predominant fee-for-service payment model, which does not reimburse for virtual visits; the considerable investment needed to deploy these technologies; and physician buy-in.

  7. The effects of video compression on acceptability of images for monitoring life sciences experiments

    Science.gov (United States)

    Haines, Richard F.; Chuang, Sherry L.

    1992-01-01

    Future manned space operations for Space Station Freedom will call for a variety of carefully planned multimedia digital communications, including full-frame-rate color video, to support remote operations of scientific experiments. This paper presents the results of an investigation to determine if video compression is a viable solution to transmission bandwidth constraints. It reports on the impact of different levels of compression and associated calculational parameters on image acceptability to investigators in life-sciences research at ARC. Three nonhuman life-sciences disciplines (plant, rodent, and primate biology) were selected for this study. A total of 33 subjects viewed experimental scenes in their own scientific disciplines. Ten plant scientists viewed still images of wheat stalks at various stages of growth. Each image was compressed to four different compression levels using the Joint Photographic Expert Group (JPEG) standard algorithm, and the images were presented in random order. Twelve and eleven staffmembers viewed 30-sec videotaped segments showing small rodents and a small primate, respectively. Each segment was repeated at four different compression levels in random order using an inverse cosine transform (ICT) algorithm. Each viewer made a series of subjective image-quality ratings. There was a significant difference in image ratings according to the type of scene viewed within disciplines; thus, ratings were scene dependent. Image (still and motion) acceptability does, in fact, vary according to compression level. The JPEG still-image-compression levels, even with the large range of 5:1 to 120:1 in this study, yielded equally high levels of acceptability. In contrast, the ICT algorithm for motion compression yielded a sharp decline in acceptability below 768 kb/sec. Therefore, if video compression is to be used as a solution for overcoming transmission bandwidth constraints, the effective management of the ratio and compression parameters

  8. Las posibilidades didácticas y manejo de Video Streaming en las clases de lengua y literatura.

    Directory of Open Access Journals (Sweden)

    José Soto Vázquez

    2009-01-01

    Full Text Available Resumen: La incorporación de las nuevas tecnologías en las aulas ha supuesto una nueva concepción del modelo educativo en el que el docente juega un papel determinante. No obstante, la diversidad de herramientas didácticas es tan amplia que necesita de trabajos parciales que enfoquen la utilidad de cada una de ellas. En este sentido, la enseñanza de las lenguas tiene en V Streaming una pieza fundamental que permite estudiar la lengua oral actual, a la vez que alienta el uso de las nuevas tecnologías.Summary: The incorporation of new technologies into the classroom has meant a new conception of the educational model where the teacher plays an important role. Nevertheless, the diversity of didactic tools is so wide that partial works are required to focus the utility of each of them. In this respect, the teaching of languages have in V Streaming a fundamental piece that allows studying current oral language, as well as encouraging the use of new technologies.

  9. CTS digital video college curriculum-sharing experiment. [Communications Technology Satellite

    Science.gov (United States)

    Lumb, D. R.; Sites, M. J.

    1974-01-01

    NASA-Ames Research Center, Stanford University, and Carleton University, Ottawa, Canada, are participating in a joint experiment to evaluate the feasibility and effectiveness of college curriculum sharing using compressed digital television and the Communications Technology Satellite (CTS). Each university will offer televised courses to the other during the 1976-1977 academic year via CTS, a joint program by NASA and the Canadian Department of Communications. The video compression techniques to be demonstrated will enable economical interconnection of educational institutions using existing and planned domestic satellites.

  10. Functional Integration between Salience and Central Executive Networks: A Role for Action Video Game Experience.

    Science.gov (United States)

    Gong, Diankun; He, Hui; Ma, Weiyi; Liu, Dongbo; Huang, Mengting; Dong, Li; Gong, Jinnan; Li, Jianfu; Luo, Cheng; Yao, Dezhong

    2016-01-01

    Action video games (AVGs) have attracted increasing research attention as they offer a unique perspective into the relation between active learning and neural plasticity. However, little research has examined the relation between AVG experience and the plasticity of neural network mechanisms. It has been proposed that AVG experience is related to the integration between Salience Network (SN) and Central Executive Network (CEN), which are responsible for attention and working memory, respectively, two cognitive functions essential for AVG playing. This study initiated a systematic investigation of this proposition by analyzing AVG experts' and amateurs' resting-state brain functions through graph theoretical analyses and functional connectivity. Results reveal enhanced intra- and internetwork functional integrations in AVG experts compared to amateurs. The findings support the possible relation between AVG experience and the neural network plasticity.

  11. Functional Integration between Salience and Central Executive Networks: A Role for Action Video Game Experience

    Directory of Open Access Journals (Sweden)

    Diankun Gong

    2016-01-01

    Full Text Available Action video games (AVGs have attracted increasing research attention as they offer a unique perspective into the relation between active learning and neural plasticity. However, little research has examined the relation between AVG experience and the plasticity of neural network mechanisms. It has been proposed that AVG experience is related to the integration between Salience Network (SN and Central Executive Network (CEN, which are responsible for attention and working memory, respectively, two cognitive functions essential for AVG playing. This study initiated a systematic investigation of this proposition by analyzing AVG experts’ and amateurs’ resting-state brain functions through graph theoretical analyses and functional connectivity. Results reveal enhanced intra- and internetwork functional integrations in AVG experts compared to amateurs. The findings support the possible relation between AVG experience and the neural network plasticity.

  12. An improved mixture-of-Gaussians background model with frame difference and blob tracking in video stream.

    Science.gov (United States)

    Yao, Li; Ling, Miaogen

    2014-01-01

    Modeling background and segmenting moving objects are significant techniques for computer vision applications. Mixture-of-Gaussians (MoG) background model is commonly used in foreground extraction in video steam. However considering the case that the objects enter the scenery and stay for a while, the foreground extraction would fail as the objects stay still and gradually merge into the background. In this paper, we adopt a blob tracking method to cope with this situation. To construct the MoG model more quickly, we add frame difference method to the foreground extracted from MoG for very crowded situations. What is more, a new shadow removal method based on RGB color space is proposed.

  13. An Improved Mixture-of-Gaussians Background Model with Frame Difference and Blob Tracking in Video Stream

    Directory of Open Access Journals (Sweden)

    Li Yao

    2014-01-01

    Full Text Available Modeling background and segmenting moving objects are significant techniques for computer vision applications. Mixture-of-Gaussians (MoG background model is commonly used in foreground extraction in video steam. However considering the case that the objects enter the scenery and stay for a while, the foreground extraction would fail as the objects stay still and gradually merge into the background. In this paper, we adopt a blob tracking method to cope with this situation. To construct the MoG model more quickly, we add frame difference method to the foreground extracted from MoG for very crowded situations. What is more, a new shadow removal method based on RGB color space is proposed.

  14. Action Video Game Experience Related to Altered Large-Scale White Matter Networks

    Directory of Open Access Journals (Sweden)

    Diankun Gong

    2017-01-01

    Full Text Available With action video games (AVGs becoming increasingly popular worldwide, the cognitive benefits of AVG experience have attracted continuous research attention over the past two decades. Research has repeatedly shown that AVG experience can causally enhance cognitive ability and is related to neural plasticity in gray matter and functional networks in the brain. However, the relation between AVG experience and the plasticity of white matter (WM network still remains unclear. WM network modulates the distribution of action potentials, coordinating the communication between brain regions and acting as the framework of neural networks. And various types of cognitive deficits are usually accompanied by impairments of WM networks. Thus, understanding this relation is essential in assessing the influence of AVG experience on neural plasticity and using AVG experience as an interventional tool for impairments of WM networks. Using graph theory, this study analyzed WM networks in AVG experts and amateurs. Results showed that AVG experience is related to altered WM networks in prefrontal networks, limbic system, and sensorimotor networks, which are related to cognitive control and sensorimotor functions. These results shed new light on the influence of AVG experience on the plasticity of WM networks and suggested the clinical applicability of AVG experience.

  15. Action Video Game Experience Related to Altered Large-Scale White Matter Networks.

    Science.gov (United States)

    Gong, Diankun; Ma, Weiyi; Gong, Jinnan; He, Hui; Dong, Li; Zhang, Dan; Li, Jianfu; Luo, Cheng; Yao, Dezhong

    2017-01-01

    With action video games (AVGs) becoming increasingly popular worldwide, the cognitive benefits of AVG experience have attracted continuous research attention over the past two decades. Research has repeatedly shown that AVG experience can causally enhance cognitive ability and is related to neural plasticity in gray matter and functional networks in the brain. However, the relation between AVG experience and the plasticity of white matter (WM) network still remains unclear. WM network modulates the distribution of action potentials, coordinating the communication between brain regions and acting as the framework of neural networks. And various types of cognitive deficits are usually accompanied by impairments of WM networks. Thus, understanding this relation is essential in assessing the influence of AVG experience on neural plasticity and using AVG experience as an interventional tool for impairments of WM networks. Using graph theory, this study analyzed WM networks in AVG experts and amateurs. Results showed that AVG experience is related to altered WM networks in prefrontal networks, limbic system, and sensorimotor networks, which are related to cognitive control and sensorimotor functions. These results shed new light on the influence of AVG experience on the plasticity of WM networks and suggested the clinical applicability of AVG experience.

  16. A radio frequency tracing experiment of bedload transport in a small braided mountain stream

    Science.gov (United States)

    Liebault, F.; Chapuis, M.; Bellot, H.; Deschatres, M.

    2009-04-01

    Radio frequency identification technology is used for monitoring the displacement of coarse particles in streams since the beginning of the 2000s. Passive integrated transponders (PIT tags) are small, cheap and long-lasting electronic tags that can be programmed with their own identification code. Initially used in environmental research for animal tracking, they have been deployed successfully in a variety of fluvial environments for coarse sediment tracing. Pioneering studies conducted in both semiarid and humid small upland streams with low intensity bedload transport gave recovery rates above 85% (Nichols 2004; Lamarre et al. 2005). Here we present an experiment of radio frequency sediment tracing implemented on a small braided mountain stream with a high intensity bedload transport and a wide active channel (mean active channel width: about 20 m). The study site is the Bouinenc Torrent, a tributary to the Bléone River in SE France that drains a 39 km² mountainous drainage basin of the Southern Prealps. In spring 2008, we deployed 451 tracers with b-axis ranging from 23 to 520 mm. Tracers were deployed along 8 cross sections located in the upstream part of the lowest 2.3 km of the stream. We developed a RFID detection system composed of an antenna and a reader unit; this system is characterized by a range of detection of 80 cm in optimal configuration. Two small intensity flow events occurred in June 2008 and entrained the tracers deployed in the most active part of the active channel. We mapped the position of the displaced tracers with a dGPS in July 2008. We obtained an overall recovery rate of 88%. The recovery rate calculated for the active tracers (those that were displaced after the flow events) was 76%. The projection of the tracer dispersion cloud on high resolution aerial photographs obtained with a drone allows us to calculate the distance of transport for each tracer. Mean and maximal distances of transport were respectively 796 m (+/- 53 m) and 2

  17. The effect of action video game experience on task-switching.

    Science.gov (United States)

    Green, C Shawn; Sugarman, Michael A; Medford, Katherine; Klobusicky, Elizabeth; Daphne Bavelier

    2012-05-01

    There is now a substantial body of work demonstrating that action video game experience results in enhancements in a wide variety of perceptual skills. More recently, several groups have also demonstrated improvements in abilities that are more cognitive in nature, in particular, the ability to efficiently switch between tasks. In a series of four experiments, we add to this body of work, demonstrating that the action video game player advantage is not exclusively due to an ability to map manual responses onto arbitrary buttons, but rather generalizes to vocal responses, is not restricted to tasks that are perceptual in nature (e.g. respond to a physical dimension of the stimulus such as its color), but generalizes to more cognitive tasks (e.g. is a number odd or even), and is present whether the switch requires a goal-switch or only a motor switch. Finally, a training study establishes that the relationship between the reduction in switch cost and action game playing is causal.

  18. Immersion in the virtual environment: the effect of a musical score on the video gaming experience.

    Science.gov (United States)

    Lipscomb, Scott D; Zehnder, Sean M

    2004-11-01

    This study provides one of very few experimental investigations into the impact of a musical soundtrack on the video gaming experience. Participants were randomly assigned to one of three experimental conditions: game-with-music, game-without-music, or music-only. After playing each of three segments of The Lord of the Rings: The Two Towers (Electronic Arts, 2002)--or, in the music-only condition, listening to the musical score that accompanies the scene--subjects responded on 21 verbal scales. Results revealed that some, but not all, of the verbal scales exhibited a statistically significant difference due to the presence of a musical score. In addition, both gender and age level were shown to be significant factors for some, but not all, of the verbal scales. Details of the specific ways in which music affects the gaming experience are provided in the body of the paper.

  19. Sending Safety Video over WiMAX in Vehicle Communications

    Directory of Open Access Journals (Sweden)

    Jun Steed Huang

    2013-10-01

    Full Text Available This paper reports on the design of an OPNET simulation platform to test the performance of sending real-time safety video over VANET (Vehicular Adhoc NETwork using the WiMAX technology. To provide a more realistic environment for streaming real-time video, a video model was created based on the study of video traffic traces captured from a realistic vehicular camera, and different design considerations were taken into account. A practical controller over real-time streaming protocol is implemented to control data traffic congestion for future road safety development. Our driving video model was then integrated with the WiMAX OPNET model along with a mobility model based on real road maps. Using this simulation platform, different mobility cases have been studied and the performance evaluated in terms of end-to-end delay, jitter and visual experience.

  20. Error resilience technique for video coding using concealment

    Science.gov (United States)

    Li, Rong; Yu, Sheng-sheng; Zhu, Li

    2009-10-01

    The traditional error resilience technique has been widely used in video coding. Many literatures have shown that with the technique's help, the video coding bit stream can been protected and the reconstructed image will get high improvement. In this paper, we review the error resilience for video coding and give the experiment of this new technology. These techniques are based on coding simultaneously for synchronization and error protection or detection. We apply the techniques to improve the performance of the multiplexing protocol and also to improve the robustness of the coded video. The techniques proposed for the video also have the advantage of simple trans-coding with bit streams complying in H.263.

  1. Troubled Waters: where Multiple Streams of Inequality Converge in the Math and Science Experiences of Nonprivileged Girls

    Science.gov (United States)

    Parrott, Laurel; Spatig, Linda; Kusimo, Patricia S.; Carter, Carolyn C.; Keyes, Marian

    Water is often hardest to navigate at the confluence of individual streams. As they experience math and science, nonprivileged girls maneuver through roiling waters where the streams of gender, ethnicity, poverty, place, and teaching practices converge. Just as waters of separate streams blend, these issues - too often considered separate factors - become blended and difficult to isolate, and the resulting turbulence produces a bumpy ride. We draw on 3 years of qualitative data collected as part of an intervention program to explore the math and science experiences and perceptions of a group of ethnically diverse, low socioeconomic status rural and urban adolescent Appalachian girls. After describing program and community contexts, we explore "opportunity to leant" issues - specifically, expectations, access to content, and support networks - and examine their schooling experiences against visions of science and math reform and pressures for accountability. Data are discussed within a framework of critical educational theory.

  2. Experiences of citizen-based reporting of rainfall events using lab-generated videos

    Science.gov (United States)

    Alfonso, Leonardo; Chacon, Juan

    2016-04-01

    Hydrologic studies rely on the availability of good-quality precipitation estimates. However, in remote areas of the world and particularly in developing countries, ground-based measurement networks are either sparse or nonexistent. This creates difficulties in the estimation of precipitation, which limits the development of hydrologic forecasting and early warning systems for these regions. The EC-FP7 WeSenseIt project aims at exploring the involvement of citizens in the observation of the water cycle with innovative sensor technologies, including mobile telephony. In particular, the project explores the use of a smartphone applications to facilitate the reporting water-related situations. Apart from the challenge of using such information for scientific purposes, the citizen engagement is one of the most important issues to address. To this end effortless methods for reporting need to be developed in order to involve as many people as possible in these experiments. A potential solution to overcome these drawbacks, consisting on lab-controlled rainfall videos have been produced to help mapping the extent and distribution of rainfall fields with minimum effort [1]. In addition, the quality of the collected rainfall information has also been studied [2] by means of different experiments with students. The present research shows the latest results of the application of this method and evaluates the experiences in some cases. [1] Alfonso, L., J. Chacón, and G. Peña-Castellanos (2015), Allowing Citizens to Effortlessly Become Rainfall Sensors, in 36th IAHR World Congress edited, The Hague, the Netherlands [2] Cortes-Arevalo, J., J. Chacón, L. Alfonso, and T. Bogaard (2015), Evaluating data quality collected by using a video rating scale to estimate and report rainfall intensity, in 36th IAHR World Congress edited, The Hague, the Netherlands

  3. The effects of gender, flow and video game experience on combat identification training.

    Science.gov (United States)

    Plummer, John Paul; Schuster, David; Keebler, Joseph R

    2017-08-01

    The present study examined the effects of gender, video game experience (VGE), and flow state on multiple indices of combat identification (CID) performance. Individuals were trained on six combat vehicles in a simulation, presented through either a stereoscopic or non-stereoscopic display. Participants then reported flow state, VGE and were tested on their ability to discriminate friend vs. foe and identify both pictures and videos of the trained vehicles. The effect of stereoscopy was not significant. There was an effect of gender across three dependent measures. For the two picture-based measures, the effect of gender was mediated by VGE. Additionally, the effect of gender was moderated by flow state on the identification measures. Overall, the study suggests that gender differences may be overcome by VGE and by achieving flow state. Selection based on these individual differences may be useful for future military simulation. Practitioner Summary: This work investigates the effect of gender, VGE and flow state on CID performance. For three measures of performance, there was a main effect of gender. Gender was mediated by previous VGE on two measures, and gender was moderated by flow state on two measures.

  4. Developing Communication Competence Using an Online Video Reflection System: Pre-Service Teachers' Experiences

    Science.gov (United States)

    Bower, Matt; Cavanagh, Michael; Moloney, Robyn; Dao, MingMing

    2011-01-01

    This paper reports on how the cognitive, behavioural and affective communication competencies of undergraduate students were developed using an online Video Reflection system. Pre-service teachers were provided with communication scenarios and asked to record short videos of one another making presentations. Students then uploaded their videos to…

  5. Using Transmission Control Protocol in the Trans-Pacific High Definition Video Satellite Communication Experiment - the Next Test

    Science.gov (United States)

    Hsu, E.

    1998-01-01

    Ths paper describes a future Transmission Control Protocol (TCP) test which was planned as a part of the Trans-Pacific High Definition Video Satellite Communications Experiment. The TCP test portion of the Trans-Pacific High Definition Video Satellite Communications Experiment intends to examine the correlation between the underlying assumptions of come TCP algorithms and the performance shortfalls observed when the algorithms are used in a stellite-based environment, and to make experimental changes to existing TCP variants to study the effects of the modifications.

  6. User Experience Evaluations in Rehabilitation Video Games for Children: A Systematic Mapping of the Literature.

    Science.gov (United States)

    Rico-Olarte, Carolina; López, Diego M; Blobel, Bernd; Kepplinger, Sara

    2017-01-01

    In recent years, the interest in user experience (UX) evaluation methods for assessing technology solutions, especially in health systems for children with special needs like cognitive disabilities, has increased. Conduct a systematic mapping study to provide an overview in the field of UX evaluations in rehabilitation video games for children. The definition of research questions, the search for primary studies and the extraction of those studies by inclusion and exclusion criteria lead to the mapping of primary papers according to a classification scheme. Main findings from this study include the detection of the target population of the selected studies, the recognition of two different ways of evaluating UX: (i) user evaluation and (ii) system evaluation, and UX measurements and devices used. This systematic mapping specifies the research gaps identified for future research works in the area.

  7. Perspective and agency during video gaming influences spatial presence experience and brain activation patterns

    Directory of Open Access Journals (Sweden)

    Havranek Michael

    2012-07-01

    Full Text Available Abstract Background The experience of spatial presence (SP, i.e., the sense of being present in a virtual environment, emerges if an individual perceives himself as 1 if he were actually located (self-location and 2 able to act in the virtual environment (possible actions. In this study, two main media factors (perspective and agency were investigated while participants played a commercially available video game. Methods The differences in SP experience and associated brain activation were compared between the conditions of game play in first person perspective (1PP and third person perspective (3PP as well as between agency, i.e., active navigation of the video game character (active, and non-agency, i.e., mere passive observation (passive. SP was assessed using standard questionnaires, and brain activation was measured using electroencephalography (EEG and sLORETA source localisation (standard low-resolution brain electromagnetic tomography. Results Higher SP ratings were obtained in the 1PP compared with the 3PP condition and in the active compared with the passive condition. On a neural level, we observed in the 1PP compared with the 3PP condition significantly less alpha band power in the parietal, the occipital and the limbic cortex. In the active compared with the passive condition, we uncovered significantly more theta band power in frontal brain regions. Conclusion We propose that manipulating the factors perspective and agency influences SP formation by either directly or indirectly modulating the ego-centric visual processing in a fronto-parietal network. The neuroscientific results are discussed in terms of the theoretical concepts of SP.

  8. Influence of Experience Level on Physical Activity During Interactive Video Gaming.

    Science.gov (United States)

    Kraft, Justin A; Russell, William D; Clark, Nathan; Helm, Jessica; Jackson, Amanda

    2015-06-01

    The ability of interactive video games (IVGs) to individualize physical demands influences their viability as a physical activity option. This study examined the influence of experience level on activity levels and affect resulting from playing a martial arts IVG. Twenty participants completed 3 15-minute trials: (1) walking, (2) IVG with no previous experience (INEXP), and (3) IVG activity after 2 hours of practice (EXP) during which heart rate (HR), step counts, metabolic equivalents of task (METs), ratings of perceived exertion (RPE), session RPE, and affect (positive/negative affect, enjoyment) were measured. Mean HR was lower during walking (107 ± 18 bpm) than during INEXP (131 ± 25 bpm) and EXP (120 ± 20 bpm). Peak HR and session RPE were lower for walking than for INEXP and EXP. No difference in mean HR was observed between IVG conditions, but peak HR and session RPE were lower for EXP than for INEXP. Walking resulted in greater postactivity reduction of negative affect; however, the IVG conditions were perceived as more enjoyable. Although the current IVG provided a greater exercise stimulus than walking, results suggest that user movements become more efficient with greater IVG experience and that exercise outcomes may decrease as a result.

  9. Evaluation of a virtual pet visit system with live video streaming of patient images over the Internet in a companion animal intensive care unit in the Netherlands.

    Science.gov (United States)

    Robben, Joris H; Melsen, Diede N; Almalik, Osama; Roomer, Wendy; Endenburg, Nienke

    2016-05-01

    To evaluate the impact of a virtual pet visit system ("TelePet" System, TPS) on owners and staff of a companion animal ICU. Longitudinal interventional study (2010-2013). Companion animal ICU at a university veterinary medical teaching hospital. Pet owners, ICU technicians. The introduction of the TPS, with live video streaming of patient images over the Internet, in a companion animal ICU. Pet owners experienced TPS as a valuable extra service. Most TPS users (72.4%) experienced less anxiety and felt less need (40.4% of TPS users) to visit their hospitalized pet in person. Most users (83.5%) shared TPS access with their family. The introduction of the TPS did not improve overall owner satisfaction, except for the score on "quality of medical treatment." Seven of 26 indicators of owner satisfaction were awarded higher scores by TPS users than by TPS nonusers in the survey after the introduction of the system. However, the lack of randomization of owners might have influenced findings. The enthusiasm of the ICU technicians for the system was tempered by the negative feedback from a small number of owners. Nevertheless they recognized the value of the system for owners. The system was user friendly and ICU staff and TPS users experienced few technical problems. As veterinary healthcare is moving toward a more client-centered approach, a virtual pet visit system, such as TPS, is a relatively simple application that may improve the well-being of most owners during the hospitalization of their pet. © Veterinary Emergency and Critical Care Society 2016.

  10. Video Observations of Children's Perspectives on Their Lived Experiences: Challenges in the Relations between the Researcher and Children

    Science.gov (United States)

    Pálmadóttir, Hrönn; Einarsdóttir, Jóhanna

    2016-01-01

    The article seeks to explore the relationship between the researcher and children aged from one to three years old. The findings are drawn from a research project in an Icelandic preschool where video recordings were used as the main method. The aim of the research project was to understand children's lived experiences when creating their…

  11. "Sure, I Would Like to Continue": A Method for Mapping the Experience of Engagement in Video Games

    Science.gov (United States)

    Schonau-Fog, Henrik; Bjorner, Thomas

    2012-01-01

    In order to explore one aspect of the engaging nature of computer games, this study will propose a method that aims at classifying the experience of engagement in video games. Inspired by a literature review, we will focus on the fundamental causes of engagement that motivate a player so much that he or she wants to continue playing. By organizing…

  12. Reactive solute transport in streams. 2. Simulation of a pH modification experiment

    Science.gov (United States)

    Runkel, R.L.; McKnight, Diane M.; Bencala, K.E.; Chapra, S.C.

    1996-01-01

    We present an application of an equilibrium-based solute transport model to a pH-modification experiment conducted on the Snake River, an acidic, metal-rich stream located in the Rocky Mountains of Colorado. During the experiment, instream pH decreased from 4.2 to 3.2, causing a marked increase in dissolved iron concentrations. Model application requires specification of several parameters that are estimated using tracer techniques, mass balance calculations, and geochemical data. Two basic questions are addressed through model application: (1) What are the processes responsible for the observed increase in dissolved iron concentrations? (2) Can the identified processes be represented within the equilibrium-based transport model? Simulation results indicate that the increase in iron was due to the dissolution of hydrous iron oxides and the photoreduction of ferric iron. Dissolution from the streambed is represented by considering a trace compartment consisting of freshly precipitated hydrous iron oxide and an abundant compartment consisting of aged precipitates that are less soluble. Spatial variability in the solubility of hydrous iron oxide is attributed to heterogeneity in the streambed sediments, temperature effects, and/or variability in the effects of photoreduction. Solubility products estimated via simulation fall within a narrow range (pK(sp) from 40.2 to 40.8) relative to the 6 order of magnitude variation reported for laboratory experiments (pK(sp) from 37.3 to 43.3). Results also support the use of an equilibrium-based transport model as the predominate features of the iron and p H profiles are reproduced. The model provides a valuable tool for quantifying the nature and extent of pH- dependent processes within the context of hydrologic transport.

  13. "Minimally invasive video-assisted thyroidectomy. Initial experience in a general surgery department".

    Science.gov (United States)

    Dobrinja, Chiara; Trevisan, Giuliano; Liguori, Gennaro

    2009-03-01

    The aim of this study is to analyze our preliminary results from minimally invasive video-assisted thyroidectomy (MIVAT) and demonstrate the feasibility of MIVAT also in non-referral centers. We report our initial experience based on a series of 47 patients selected for MIVAT at General Surgery Department of University of Trieste during a period from May 2005 to February 2007. The eligibility criteria were rigorously observed. Age, goiter volume, major diameter of the dominant nodule, operative times, pathologic findings, postoperative pain, length of hospital stay, cosmetic results, and complications were retrospectively analyzed. Thyroid lobectomy was successfully accomplished in 33 cases, total thyroidectomy in 14. Conversion to standard cervicotomy was required in three patients (6%). Mean operative time of lobectomy was 82.6 min and 118.7 for total thyroidectomy. Postoperative complications included 11 (23.4%) transient hypocalcemias, 2 (4.2%) hematomas, and 2 (4.2%) temporary laryngeal nerve palsies. None-recurrent nerve palsies was observed. The cosmetic result was excellent in most cases. Our experience demonstrates that MIVAT, after adequate training, is feasible and safe, with results comparable to conventional thyroidectomy, also in a General Surgery Department, from a dedicated team, with a sufficient and specific activity volume.

  14. A Hyporheic Mesocosm Experiment: Influence of Quantity and Quality of stream-source DOC on Rates of Hyporheic Metabolism

    Science.gov (United States)

    Serchan, S. P.; Wondzell, S. M.; Haggerty, R.; Pennington, R.; Feris, K. P.; Sanfilippo, A. R.; Reeder, W. J.; Tonina, D.

    2016-12-01

    Hyporheic zone biogeochemical processes can influence stream water chemistry. Some estimates show that 50-90% stream water CO2 is produced in the hyporheic zone through heterotrophic metabolism of organic matter, usually supplied from the stream as dissolved organic carbon (DOC). Preliminary results from our well network at the HJ Andrews WS1, indicate that dissolved inorganic carbon (DIC) is 1.5-2 times higher in the hyporheic zone than in stream water. Conversely, DOC (mg/L) is 1.5 times higher in stream water than in the hyporheic zone throughout the year. Overall, the hyporheic zone appears to be a net source of DIC. However, the increase in DIC along hyporheic flow paths is approximately 10-times greater than the loss of DOC, suggesting that metabolism of buried particulate organic carbon (POC) is a major source of organic carbon for microbial metabolism. However, we cannot completely rule out alternative sources of DIC, especially those originating in the overlying riparian soil, because hyporheic processes are difficult to isolate in well networks. To study hyporheic zone biogeochemical processes, particularly the transformation of organic carbon to inorganic carbon species, we designed and built six replicate 2-m long hyporheic mesocosms in which we are conducting DOC amendment experiments. We examine the role of DOC quality and quantity on hyporheic respiration by injecting labile (acetate) and refractory (fulvic acid) organic carbon and comparing rates of O2 consumption, DOC loss, and DIC gains against a control. We expect that stream source DOC is limiting in this small headwater stream, forcing hyporheic metabolism to rely on buried POC. However, the long burial time of POC suggests it is likely of low quality so that supplying labile DOC in stream water should shift hyporheic metabolism away from POC rather than increase the overall rate of metabolism. Future experiments will examine natural sources of DOC (stream periphyton, leaf, and soil humic

  15. Intelligent video surveillance systems

    CERN Document Server

    Dufour, Jean-Yves

    2012-01-01

    Belonging to the wider academic field of computer vision, video analytics has aroused a phenomenal surge of interest since the current millennium. Video analytics is intended to solve the problem of the incapability of exploiting video streams in real time for the purpose of detection or anticipation. It involves analyzing the videos using algorithms that detect and track objects of interest over time and that indicate the presence of events or suspect behavior involving these objects.The aims of this book are to highlight the operational attempts of video analytics, to identify possi

  16. Quantifying Reaeration Rates in Alpine Streams Using Deliberate Gas Tracer Experiments

    Directory of Open Access Journals (Sweden)

    Andrew Benson

    2014-04-01

    Full Text Available Gas exchange across the air-water interface is a critical process that maintains adequate dissolved oxygen (DO in the water column to support life. Oxygen reaeration rates can be accurately measured using deliberate gas tracers, like sulfur hexafluoride (SF6 or xenon (Xe. Two continuous release experiments were conducted in different creeks in the Sierra Nevada of California: Sagehen Creek in September, 2009, using SF6 and Martis Creek in August, 2012, using both SF6 and Xe. Measuring gas loss along the creek, which was approximated with the one-dimensional advection-dispersion equation, allows for the estimation of the SF6 or Xe reaeration coefficient (KSF6, KXe, which is converted to DO reaeration (KDO or K2 using Schmidt numbers. Mean KSF6 for upper and lower Sagehen and Martis Creeks were, respectively, 34 day−1, 37 day−1 and 33 day−1, with corresponding KDOs of 61 day−1, 66 day−1 and 47 day−1. In Martis Creek, KXe was slightly higher (21% than KSF6, but the calculated KDO from SF6 agreed with the calculated KDO from Xe within about 15%; this difference may be due to bubble-enhanced gas transfer. Established empirical equations of KDO using stream characteristics did a poor job predicting KDO for both creeks.

  17. Enhancing the Assessment Experience: Improving Student Perceptions, Engagement and Understanding Using Online Video Feedback

    Science.gov (United States)

    West, John; Turner, Will

    2016-01-01

    Individualised video screencasts with accompanying narration were used to provide assessment feedback to a large number (n = 299) of first-year Bachelor of Education students at Edith Cowan University in Western Australia. An anonymous online survey revealed that nearly three times as many respondents (61%) preferred video feedback to written…

  18. Positive effect on patient experience of video information given prior to cardiovascular magnetic resonance imaging: A clinical trial.

    Science.gov (United States)

    Ahlander, Britt-Marie; Engvall, Jan; Maret, Eva; Ericsson, Elisabeth

    2017-11-17

    To evaluate the effect of video information given before cardiovascular magnetic resonance imaging on patient anxiety and to compare patient experiences of cardiovascular magnetic resonance imaging versus myocardial perfusion scintigraphy. To evaluate whether additional information has an impact on motion artefacts. Cardiovascular magnetic resonance imaging and myocardial perfusion scintigraphy are technically advanced methods for the evaluation of heart diseases. Although cardiovascular magnetic resonance imaging is considered to be painless, patients may experience anxiety due to the closed environment. A prospective randomised intervention study, not registered. The sample (n = 148) consisted of 97 patients referred for cardiovascular magnetic resonance imaging, randomised to receive either video information in addition to standard text-information (CMR-video/n = 49) or standard text-information alone (CMR-standard/n = 48). A third group undergoing myocardial perfusion scintigraphy (n = 51) was compared with the cardiovascular magnetic resonance imaging-standard group. Anxiety was evaluated before, immediately after the procedure and 1 week later. Five questionnaires were used: Cardiac Anxiety Questionnaire, State-Trait Anxiety Inventory, Hospital Anxiety and Depression scale, MRI Fear Survey Schedule and the MRI-Anxiety Questionnaire. Motion artefacts were evaluated by three observers, blinded to the information given. Data were collected between April 2015-April 2016. The study followed the CONSORT guidelines. The CMR-video group scored lower (better) than the cardiovascular magnetic resonance imaging-standard group in the factor Relaxation (p = .039) but not in the factor Anxiety. Anxiety levels were lower during scintigraphic examinations compared to the CMR-standard group (p magnetic resonance imaging increased by adding video information prior the exam, which is important in relation to perceived quality in nursing. No effect was seen on motion

  19. Patients’ Experiences with Specialist Care via Video Consultation in Primary Healthcare in Rural Areas

    Directory of Open Access Journals (Sweden)

    Annette M. Johansson

    2014-01-01

    Full Text Available Introduction. Video consultation (VC can improve access to specialist care, especially for individuals who live in rural areas that are long distances from specialist clinics. Aim. The aim of this study was to describe patients’ experiences with specialist care via VC encounters. Method. Interviews were conducted with 26 patients who had participated in a VC encounter. The data were analysed using thematic content analysis. Result. The analysis resulted in two themes. The theme “confident with the technology” was constructed from the categories “possibilities and obstacles in using VC encounters” and “advantages and disadvantages of the technology.” The theme “personal satisfaction with the VC encounters” was constructed from the categories “support from the healthcare personnel,” “perceived security,” and “satisfaction with the specialist consultation.” Conclusion. The patients who did not think that the VC was the best care still considered that the visit was adequate because they did not have to travel. An important finding was that the patients’ perceived even short distances to specialty care as expensive journeys because many patients had low incomes. Among the patients who had more than one VC, the second encounter was perceived as safer. Additionally, good communication was essential for the patient’s perception of security during the VC encounter.

  20. Patients' Experiences with Specialist Care via Video Consultation in Primary Healthcare in Rural Areas

    Science.gov (United States)

    Johansson, Annette M.; Lindberg, Inger; Söderberg, Siv

    2014-01-01

    Introduction. Video consultation (VC) can improve access to specialist care, especially for individuals who live in rural areas that are long distances from specialist clinics. Aim. The aim of this study was to describe patients' experiences with specialist care via VC encounters. Method. Interviews were conducted with 26 patients who had participated in a VC encounter. The data were analysed using thematic content analysis. Result. The analysis resulted in two themes. The theme “confident with the technology” was constructed from the categories “possibilities and obstacles in using VC encounters” and “advantages and disadvantages of the technology.” The theme “personal satisfaction with the VC encounters” was constructed from the categories “support from the healthcare personnel,” “perceived security,” and “satisfaction with the specialist consultation.” Conclusion. The patients who did not think that the VC was the best care still considered that the visit was adequate because they did not have to travel. An important finding was that the patients' perceived even short distances to specialty care as expensive journeys because many patients had low incomes. Among the patients who had more than one VC, the second encounter was perceived as safer. Additionally, good communication was essential for the patient's perception of security during the VC encounter. PMID:25243009

  1. MR360: Mixed Reality Rendering for 360° Panoramic Videos.

    Science.gov (United States)

    Rhee, Taehyun; Petikam, Lohit; Allen, Benjamin; Chalmers, Andrew

    2017-04-01

    This paper presents a novel immersive system called MR360 that provides interactive mixed reality (MR) experiences using a conventional low dynamic range (LDR) 360° panoramic video (360-video) shown in head mounted displays (HMDs). MR360 seamlessly composites 3D virtual objects into a live 360-video using the input panoramic video as the lighting source to illuminate the virtual objects. Image based lighting (IBL) is perceptually optimized to provide fast and believable results using the LDR 360-video as the lighting source. Regions of most salient lights in the input panoramic video are detected to optimize the number of lights used to cast perceptible shadows. Then, the areas of the detected lights adjust the penumbra of the shadow to provide realistic soft shadows. Finally, our real-time differential rendering synthesizes illumination of the virtual 3D objects into the 360-video. MR360 provides the illusion of interacting with objects in a video, which are actually 3D virtual objects seamlessly composited into the background of the 360-video. MR360 was implemented in a commercial game engine and tested using various 360-videos. Since our MR360 pipeline does not require any pre-computation, it can synthesize an interactive MR scene using a live 360-video stream while providing realistic high performance rendering suitable for HMDs.

  2. Video Rating in Neurodegenerative Disease Clinical Trials: The Experience of PRION-1

    Directory of Open Access Journals (Sweden)

    Christopher Carswell

    2012-08-01

    Full Text Available Background/Aims: Large clinical trials including patients with uncommon diseases involve assessors in different geographical locations, resulting in considerable inter-rater variability in assessment scores. As video recordings of examinations, which can be individually rated, may eliminate such variability, we measured the agreement between a single video rater and multiple examining physicians in the context of PRION-1, a clinical trial of the antimalarial drug quinacrine in human prion diseases. Methods: We analysed a 43-component neurocognitive assessment battery, on 101 patients with Creutzfeldt-Jakob disease, focusing on the correlation and agreement between examining physicians and a single video rater. Results: In total, 335 videos of examinations of 101 patients who were video-recorded over the 4-year trial period were assessed. For neurocognitive examination, inter-observer concordance was generally excellent. Highly visual neurological examination domains (e.g. finger-nose-finger assessment of ataxia had good inter-rater correlation, whereas those dependent on non-visual clues (e.g. power or reflexes correlated poorly. Some non-visual neurological domains were surprisingly concordant, such as limb muscle tone. Conclusion: Cognitive assessments and selected neurological domains can be practically and accurately recorded in a clinical trial using video rating. Video recording of examinations is a valuable addition to any trial provided appropriate selection of assessment instruments is used and rigorous training of assessors is undertaken.

  3. MPEG-4 video compression optimization research

    Science.gov (United States)

    Wei, Xianmin

    2011-10-01

    In order to make a large amount of video data compression and effectively with limited network bandwidth to transfer smoothly, this article using the MPEG-4 compression technology to compress video stream. In the network transmission, according to the characteristics of video stream, for transmission technology to carry out full analysis and optimization, and combining current network bandwidth status and protocol, to establish one network model with transferring and playback video streaming effectively. Through a combination of these two areas, significantly improved compression and storage of video files and network transmission efficiency, increased video processing power.

  4. Automatic tracking of cells for video microscopy in patch clamp experiments.

    Science.gov (United States)

    Peixoto, Helton M; Munguba, Hermany; Cruz, Rossana M S; Guerreiro, Ana M G; Leao, Richardson N

    2014-06-20

    Visualisation of neurons labeled with fluorescent proteins or compounds generally require exposure to intense light for a relatively long period of time, often leading to bleaching of the fluorescent probe and photodamage of the tissue. Here we created a technique to drastically shorten light exposure and improve the targeting of fluorescent labeled cells that is specially useful for patch-clamp recordings. We applied image tracking and mask overlay to reduce the time of fluorescence exposure and minimise mistakes when identifying neurons. Neurons are first identified according to visual criteria (e.g. fluorescence protein expression, shape, viability etc.) and a transmission microscopy image Differential Interference Contrast (DIC) or Dodt contrast containing the cell used as a reference for the tracking algorithm. A fluorescence image can also be acquired later to be used as a mask (that can be overlaid on the target during live transmission video). As patch-clamp experiments require translating the microscope stage, we used pattern matching to track reference neurons in order to move the fluorescence mask to match the new position of the objective in relation to the sample. For the image processing we used the Open Source Computer Vision (OpenCV) library, including the Speeded-Up Robust Features (SURF) for tracking cells. The dataset of images (n = 720) was analyzed under normal conditions of acquisition and with influence of noise (defocusing and brightness). We validated the method in dissociated neuronal cultures and fresh brain slices expressing Enhanced Yellow Fluorescent Protein (eYFP) or Tandem Dimer Tomato (tdTomato) proteins, which considerably decreased the exposure to fluorescence excitation, thereby minimising photodamage. We also show that the neuron tracking can be used in differential interference contrast or Dodt contrast microscopy. The techniques of digital image processing used in this work are an important addition to the set of microscopy

  5. Exploring Collaboration in Video Games for Children - Game Prototype and Experiment

    OpenAIRE

    Hovind, David Johän

    2016-01-01

    Children today, are exposed to video games from an early age in the form of tablets, smart phones and computers. Social interaction is a big part of why we play video games and is a way for us to socialize with friends and strangers. This thesis seeks to explore these areas by creating a video game, focusing on social interaction to stimulate collaboration children. The main research goals of this thesis was to create a game prototype that focuses on social interaction and collaboration,...

  6. Interactive video algorithms and technologies

    CERN Document Server

    Hammoud, Riad

    2006-01-01

    This book covers both algorithms and technologies of interactive videos, so that businesses in IT and data managements, scientists and software engineers in video processing and computer vision, coaches and instructors that use video technology in teaching, and finally end-users will greatly benefit from it. This book contains excellent scientific contributions made by a number of pioneering scientists and experts from around the globe. It consists of five parts. The first part introduces the reader to interactive video and video summarization and presents effective methodologies for automatic abstraction of a single video sequence, a set of video sequences, and a combined audio-video sequence. In the second part, a list of advanced algorithms and methodologies for automatic and semi-automatic analysis and editing of audio-video documents are presented. The third part tackles a more challenging level of automatic video re-structuring, filtering of video stream by extracting of highlights, events, and meaningf...

  7. Estimating groundwater-ephemeral stream exchange in hyper-arid environments: Field experiments and numerical simulations

    Science.gov (United States)

    Wang, Ping; Pozdniakov, Sergey P.; Vasilevskiy, Peter Yu.

    2017-12-01

    Surface water infiltration from ephemeral dryland streams is particularly important in hyporheic exchange and biogeochemical processes in arid and semi-arid regions. However, streamflow transmission losses can vary significantly, partly due to spatiotemporal variations in streambed permeability. To extend our understanding of changes in streambed hydraulic properties, field investigations of streambed hydraulic conductivity were conducted in an ephemeral dryland stream in north-western China during high and low streamflow periods. Additionally, streamflow transmission losses were numerically estimated using combined stream and groundwater hydraulic head data and stream and streambed temperature data. An analysis of slug test data at two different river flow stages (one test was performed at a low river stage with clean water and the other at a high river stage with muddy water) suggested that sedimentation from fine-grained particles, i.e., physical clogging processes, likely led to a reduction in streambed hydraulic properties. To account for the effects of streambed clogging on changes in hydraulic properties, an iteratively increasing total hydraulic resistance during the slug test was considered to correct the estimation of streambed hydraulic conductivity. The stream and streambed temperature can also greatly influence the hydraulic properties of the streambed. One-dimensional coupled water and heat flux modelling with HYDRUS-1D was used to quantify the effects of seasonal changes in stream and streambed temperature on streamflow losses. During the period from 6 August 2014 to 4 June 2015, the total infiltration estimated using temperature-dependent hydraulic conductivity accounted for approximately 88% of that using temperature-independent hydraulic conductivity. Streambed clogging processes associated with fine particle settling/wash up cycles during flow events, and seasonal changes in streamflow temperature are two considerable factors that affect water

  8. Gasless video-assisted bilateral thyroidectomy by the anterior chest wall approach: 4 years of experience.

    Science.gov (United States)

    Cai, Qian; Huang, Xiao-ming; Sun, Wei; Zheng, Yi-qing; Liang, Fa-ya; Han, Ping; Jiang, Xiao-yu

    2012-06-01

    Thyroidectomy can be performed in a variety of ways, and gasless video-assisted approaches have recently become more popular. We performed a study of thyroidectomy on 77 patients with bilateral thyroid lesions carried out using a gasless video-assisted unilateral anterior chest wall approach. Seventy-seven patients underwent bilateral thyroidectomy by the gasless video-assisted unilateral anterior chest wall approach, whereas 64 patients underwent conventional surgery during the same time frame and were considered to be the control group. The eligibility criteria for thyroid surgery by gasless video-assisted unilateral anterior chest wall approach were: no previous neck surgical history, no radiotherapy history, a diagnosis of benign thyroid tumor according to preoperative computed tomographic scan, no inflammation-related diseases or thyroid hyperfunction, no lymphadenectasis, and bilateral tumors ≤ 4 cm in diameter (1 side ≤ 2 cm, located in the lower part of the thyroid and near the surface of the thyroid). The 2 groups were compared by surgical style, complications, operative time, cosmetic result, and postoperative pain. The 2 groups were matched in terms of age and sex; the scoring for operative procedure (P=0.443), postoperative drainage (P=0.686), and postoperative pain (P=0.294) were not significantly different. The gasless video-assisted group had less bleeding during surgery than the conventional group and had better cosmetic results (Pvideo-assisted group had 1 case of ecchymoma and 1 case of temporary recurrent laryngeal nerve paralysis, but both recovered within a month. The complication rates in the 2 groups were not significantly different (χ=1.423, P=0.292). The gasless video-assisted thyroidectomy by the unilateral anterior chest wall approach is a safe and feasible way to treat patients with benign bilateral thyroid lesion with good cosmetic results. The gasless video-assisted thyroidectomy is a valid surgical option for selected patients

  9. Using MPEG DASH SRD for zoomable and navigable video

    NARCIS (Netherlands)

    D'Acunto, L.; Berg, J. van den; Thomas, E.; Niamut, O.A.

    2016-01-01

    This paper presents a video streaming client implementation that makes use of the Spatial Relationship Description (SRD) feature of the MPEG-DASH standard, to provide a zoomable and navigable video to an end user. SRD allows a video streaming client to request spatial subparts of a particular video

  10. A Case Study of an Experiment Using Streaming of Lectures in Teaching Engineering Mathematics

    Science.gov (United States)

    Fredriksen, Helge

    2015-01-01

    To support the possibility of taking an online engineering degree programme, Narvik University College has chosen to facilitate a streaming service of all lectures conducted by the college. At the Bodø college campus, in the academic year of 2012/2013, these online lectures were used as a central component in a didactic innovation project. The aim…

  11. Modélisation et optimisation de la qualité d'expérience client des services data sur le réseau mobile. Application au vidéo streaming

    OpenAIRE

    Bouzian, Mohamed

    2017-01-01

    In recent years, mobile devices have become more powerful in terms of computing power, memory, size and screen quality. These improvements have greatly stimulated demand for multimedia services including video streaming. Moreover, customers are increasingly demanding in terms of the quality rendered on this type of service. In addition, a bad experience of video streaming has a great impact on the perception that customers have of the operator. Optimizing the quality of experience (QoE) of cu...

  12. Developing a Video Steganography Toolkit

    OpenAIRE

    Ridgway, James; Stannett, Mike

    2014-01-01

    Although techniques for separate image and audio steganography are widely known, relatively little has been described concerning the hiding of information within video streams ("video steganography"). In this paper we review the current state of the art in this field, and describe the key issues we have encountered in developing a practical video steganography system. A supporting video is also available online at http://www.youtube.com/watch?v=YhnlHmZolRM

  13. What knowledge counts? Insights from an action research project using participatory video with grassroots innovation experiences

    Energy Technology Data Exchange (ETDEWEB)

    Boni, A.; Leivas, M.; Talon, A.; De La Fuente, T.; Pellicer-Sifres, V.; Belda-Miquel, S.; Lopez-Fogues, A.; Arias, B

    2016-07-01

    This paper presents a contribution on a participatory action-research process using Participatory Video (PV) methodology. Duringsix months, a group of 6 facilitators and 9 members of two grassroots innovation initiatives (Solar Dómada and Fuel Poverty Group) took part of the process and produced two videos during a five-st age PV process, from initial definition and planning to public screening and debate of the videos. We present some insightrs from that research using an original framework developed to analyze PV process: the eParc Cube. This framework examines the interaction between knowledge production, participation and communicative spaces that happen during PV. We conclude reflecting on the social relevance of that kind of research considering the impact among of the coresearchers of both process and products. (Author)

  14. Students’ Learning Experiences from Didactic Teaching Sessions Including Patient Case Examples as Either Text or Video: A Qualitative Study

    DEFF Research Database (Denmark)

    Pedersen, Kamilla; Holdgaard, Martin Møller; Paltved, Charlotte

    2017-01-01

    on students' patient-centeredness. Video-based patient cases are probably more effective than text-based patient cases in fostering patient-centered perspectives in medical students. Teachers sharing stories from their own clinical experiences stimulates both engagement and excitement, but may also provoke......' perceptions of psychiatric patients and students' reflections on meeting and communicating with psychiatric patients. METHODS: The authors conducted group interviews with 30 medical students who volunteered to participate in interviews and applied inductive thematic content analysis to the transcribed....... Students taught with video-based patient cases, in contrast, often referred to the patient cases when highlighting new insights, including the importance of patient perspectives when communicating with patients. CONCLUSION: The format of patient cases included in teaching may have a substantial impact...

  15. Energy Expenditure during Physically Interactive Video Game Playing in Male College Students with Different Playing Experience

    Science.gov (United States)

    Sell, Katie; Lillie, Tia; Taylor, Julie

    2008-01-01

    Objective: Researchers have yet to explore the effect of physically interactive video game playing on energy expenditure, despite its potential for meeting current minimal daily activity and energy expenditure recommendations. Participants and Methods: Nineteen male college students-12 experienced "Dance Dance Revolution" (DDR) players and 7…

  16. Forecasting the Market for New Communication Technology: The Home Video Player Experience.

    Science.gov (United States)

    Klopfenstein, Bruce C.

    This paper describes a critical study of the available forecasts and forecasting studies for the home video player market over a 15-year period which was undertaken to discover why so many forecasts were wrong about consumer adoption of home videocassette players and videodisk players, the reasons for these errors, and ways in which this knowledge…

  17. Experiences, Appearances, and Interprofessional Training: The Instructional Use of Video in Post-Simulation Debriefings

    Science.gov (United States)

    Johansson, Elin; Lindwall, Oskar; Rystedt, Hans

    2017-01-01

    Through close analyses of the interaction that takes place between students and facilitators, this study investigates the instructional use of video in post-simulation debriefings. The empirical material consists of recordings of 40 debriefings that took place after simulation-based training scenarios in health care education. During the…

  18. Leveling Up: Video Games, Development and the Narrated Everyday Experiences of Male College Students

    Science.gov (United States)

    Haddad, Vanessa L.

    2016-01-01

    Video games have become an integral part of the day to day lives of many people across gender, race, and age in the United States. They have become particularly important in the college student population, with nearly two thirds of all college students playing on a regular basis (Lee, 2003). While much of the scholarly research in this area…

  19. Psychophysiological Assessment Of Fear Experience In Response To Sound During Computer Video Gameplay

    DEFF Research Database (Denmark)

    Garner, Tom Alexander; Grimshaw, Mark

    2013-01-01

    The potential value of a looping biometric feedback system as a key component of adaptive computer video games is significant. Psychophysiological measures are essential to the development of an automated emotion recognition program, capable of interpreting physiological data into models of affect...... is the primary affective stimuli....

  20. MoViE: Experiences and attitudes—Learning with a mobile social video application

    Directory of Open Access Journals (Sweden)

    Pauliina Tuomi

    2010-10-01

    Full Text Available Digital media is increasingly finding its way into the discussions of the classroom. Particularly interest is placed on mobile learning—the learning and teaching practices done with or via different mobile devices. Learning with the help of mobile devices is increasingly common and it is considered to be one of the 21st century skills children should adapt already in early stages in schools. The article presents both qualitative and quantitative study on mobile social video application, MoViE, as a part of teaching in biology and geography in 8th and 9th grades. The multidisciplinary data was processed to answer the following question: How did the use of mobile videos promote learning? The actual research question is however twofold: On one hand, it studies the use of mobile videos in mobile learning. On the other hand, it sets out to investigate the implementation of mobile video sharing as a part of the teaching and learning activities.

  1. Elders' Usability, Dependability, and Flow Experiences on Embodied Interactive Video Games

    Science.gov (United States)

    Hwang, Ming-Yueh; Hong, Jon-Chao; Hao, Yung-wei; Jong, Jyh-Tsorng

    2011-01-01

    Daily physical activities may slow down the deterioration of cognitive aging. This study intended to develop embodiment interactive video games with friendly human-machine interface to break through the elder's literacy, cognitive aging, and psychomotor hindrances toward technology. Another objective was to understand, through field experiments…

  2. Large-scale laboratory testing of bedload-monitoring technologies: overview of the StreamLab06 Experiments

    Science.gov (United States)

    Marr, Jeffrey D.G.; Gray, John R.; Davis, Broderick E.; Ellis, Chris; Johnson, Sara; Gray, John R.; Laronne, Jonathan B.; Marr, Jeffrey D.G.

    2010-01-01

    A 3-month-long, large-scale flume experiment involving research and testing of selected conventional and surrogate bedload-monitoring technologies was conducted in the Main Channel at the St. Anthony Falls Laboratory under the auspices of the National Center for Earth-surface Dynamics. These experiments, dubbed StreamLab06, involved 25 researchers and volunteers from academia, government, and the private sector. The research channel was equipped with a sediment-recirculation system and a sediment-flux monitoring system that allowed continuous measurement of sediment flux in the flume and provided a data set by which samplers were evaluated. Selected bedload-measurement technologies were tested under a range of flow and sediment-transport conditions. The experiment was conducted in two phases. The bed material in phase I was well-sorted siliceous sand (0.6-1.8 mm median diameter). A gravel mixture (1-32 mm median diameter) composed the bed material in phase II. Four conventional bedload samplers – a standard Helley-Smith, Elwha, BLH-84, and Toutle River II (TR-2) sampler – were manually deployed as part of both experiment phases. Bedload traps were deployed in study Phase II. Two surrogate bedload samplers – stationarymounted down-looking 600 kHz and 1200 kHz acoustic Doppler current profilers – were deployed in experiment phase II. This paper presents an overview of the experiment including the specific data-collection technologies used and the ambient hydraulic, sediment-transport and environmental conditions measured as part of the experiment. All data collected as part of the StreamLab06 experiments are, or will be available to the research community.

  3. ATLAS Live: Collaborative Information Streams

    Science.gov (United States)

    Goldfarb, Steven; ATLAS Collaboration

    2011-12-01

    I report on a pilot project launched in 2010 focusing on facilitating communication and information exchange within the ATLAS Collaboration, through the combination of digital signage software and webcasting. The project, called ATLAS Live, implements video streams of information, ranging from detailed detector and data status to educational and outreach material. The content, including text, images, video and audio, is collected, visualised and scheduled using digital signage software. The system is robust and flexible, utilizing scripts to input data from remote sources, such as the CERN Document Server, Indico, or any available URL, and to integrate these sources into professional-quality streams, including text scrolling, transition effects, inter and intra-screen divisibility. Information is published via the encoding and webcasting of standard video streams, viewable on all common platforms, using a web browser or other common video tool. Authorisation is enforced at the level of the streaming and at the web portals, using the CERN SSO system.

  4. ATLAS Live: Collaborative Information Streams

    CERN Document Server

    Goldfarb, S; The ATLAS collaboration

    2011-01-01

    I report on a pilot project launched in 2010 focusing on facilitating communication and information exchange within the ATLAS Collaboration, through the combination of digital signage software and webcasting. The project, called ATLAS Live, implements video streams of information, ranging from detailed detector and data status to educational and outreach material. The content, including text, images, video and audio, is collected, visualised and scheduled using digital signage software. The system is robust and flexible, utilizing scripts to input data from remote sources, such as the CERN Document Server, Indico, or any available URL, and to integrate these sources into professional-quality streams, including text scrolling, transition effects, inter and intra-screen divisibility. Information is published via the encoding and webcasting of standard video streams, viewable on all common platforms, using a web browser or other common video tool. Authorisation is enforced at the level of the streaming and at th...

  5. ATLAS Live: Collaborative Information Streams

    CERN Document Server

    Goldfarb, S; The ATLAS collaboration

    2010-01-01

    I report on a pilot project launched in 2010 focusing on facilitating communication and information exchange within the ATLAS Collaboration, through the combination of digital signage software and webcasting. The project, called ATLAS Live, implements video streams of information, ranging from detailed detector and data status to educational and outreach material. The content, including text, images, video and audio, is collected, visualised and scheduled using the SCALA digital signage software system. The system is robust and flexible, allowing for the usage of scripts to input data from remote sources, such as the CERN Document Server, Indico, or any available URL, and to integrate these sources into professional-quality streams, including text scrolling, transition effects, inter and intrascreen divisibility. The video is made available to the collaboration or public through the encoding and webcasting of standard video streams, viewable on all common platforms, using a web browser or other common video t...

  6. THE FREEDOM IN VIDEO GAME LOCALIZATION (How Indonesian Game Translator applied Carte Blanche of Translation to Preserve Game Experience

    Directory of Open Access Journals (Sweden)

    Agung Prasetyo Wibowo

    2017-12-01

    Full Text Available This paper addresses the issue of video game localisation in MMORPG video game that focusing on the freedom of the translator in transferring meaning in the in-game text assets of video games. Games, regardless of their forms, are the media of entertainments. Foreign audiences may have different expectations on how they wish to be entertained. They most certainly have their own canon of cultural references that they will put into relation to any content of the game. Localization has to take all these things into account, and subsequently the localization process can involve the addition, removal or replacement of elements of the product. Game localisation allows translators to transcreate the things that are necessary to preserve the game experience and to produce a fresh and engaging translation. In this paper, the writers cast a spotlight on translators, progressing from our analysis focused on games as translation texts and as products. The result of this paper shows about how the translator used the freedom of the translator or the degree of creativity that they may have when adapting the game. Concisely, the more complex and creative a storyline, the more useful transcreation may turn in the translation process.

  7. Patients' statements and experiences concerning receiving mechanical ventilation: a prospective video-recorded study.

    Science.gov (United States)

    Karlsson, Veronika; Lindahl, Berit; Bergbom, Ingegerd

    2012-09-01

    Prospective studies using video-recordings of patients during mechanical ventilator treatment (MVT) while conscious have not previously been published. The aim was to describe patients' statements, communication and facial expressions during a video-recorded interview while undergoing MVT. Content analysis and hermeneutics inspired by the philosophy of Gadamer were used. The patients experienced almost constant difficulties in breathing and lost their voice. The most common types of communication techniques patients used were nodding or shaking the head. Their expressions were interpreted as stiffened facial expression, tense body position and feelings of sadness and sorrow. Nursing care for patients' conscious during MVT is challenging as it creates new demands regarding the content of the care provided. In caring for patients undergoing MVT while conscious, establishing a caring relationship, making patients feel safe and helping them to communicate seem to be most important for alleviating discomfort and instilling hope. © 2011 Blackwell Publishing Ltd.

  8. Community health workers' experiences of using video teaching tools during home visits-A pilot study.

    Science.gov (United States)

    Coetzee, Bronwyné; Kohrman, Hannah; Tomlinson, Mark; Mbewu, Nokwanele; Le Roux, Ingrid; Adam, Maya

    2017-09-05

    Innovations in health, such as the use of tablet computers, show promise in broadening the scope of work of community health workers (CHWs), and play an important role in keeping CHWs and their clients up to date with advancements in health. While the use of mobile phones and tablets is innovative, the applicability of these technologies in different contexts remains poorly understood. Furthermore, little is known about the acceptability and feasibility of the use of video teaching tools on such devices across diverse contexts. In this study, we aimed to explore the acceptability and feasibility of using tablets with teaching videos (about HIV, alcohol, nutrition and breastfeeding) to support the health promotion efforts of 24 CHWs who work with pregnant mothers and mothers of young children in an urban township in South Africa. Between November 2015 and May 2016, we conducted focus groups and identified four key themes (with several sub-themes) that demonstrated factors related to the acceptability and feasibility of these devices and their content. Focus group transcripts were analysed thematically using qualitative data analysis software. The findings indicated that while the devices contained several supportive features (such as lightening the workload, and stimulating interest in their work), they also contained several restrictive features (safety and confidentiality). CHWs considered the video content an important tool to engage not only their clients but also family members and the community at large. Issues surrounding safety, privacy and confidentiality of using these devices require careful consideration prior to implementation in large-scale studies. Furthermore, stigma associated with household visits by CHWs and the nature of their work also need to be addressed by researchers and programme implementers. Overall, CHWs deemed the devices and the video content an acceptable and feasible means with which to provide health promotion and education among

  9. Guest blog: Jacob Davidsen and Paul McIlvenny on Experiments with Big Video

    DEFF Research Database (Denmark)

    Davidsen, Jacob; Mcilvenny, Paul Bruce

    2016-01-01

    How good are your video records? One angle? Two? Wide-angle? Was the camera static or did you move to catch things – and miss other things? How good was the sound? All of us have occasionally been frustrated with what we find on the screen when we come to analyse it, but Jacob Davidsen and Paul M......Ilvenny have some more fundamental concerns. Just how “big” should data be?...

  10. User Throughput-Based Quality of Experience

    DEFF Research Database (Denmark)

    Hiranandani, Bhavesh; Sarkar, Mahasweta; Mihovska, Albena

    Satisfaction of end users is one of the most important factors for every service provider. Given that a lot of factors along with the network conditions affect the user’s experience, the network quality given by the Quality of Service (QoS) parameters alone cannot provide an accurate measure...... of the users Quality of Experience (QoE). Today, most of the airlines have started providing in-flight wi-fi services, which allow their passengers to use Internet services to send and receive e-mails, and stream video from various online service providers while on board the flight. Statistics show that more...... than 50% of the passengers use the provided wi-fi service to stream video, therefore, their perception of the video service will be determining for the service provider’s performance. One easy way to evaluate the perceived video streaming (i.e. QoE) is by estimating the frequency of stalls. In our...

  11. Fibromyalgia patients' own experiences of video self-interpretation: a phenomenological-hermeneutic study.

    Science.gov (United States)

    Horwitz, Eva Bojner; Theorell, Töres; Anderberg, Ulla Maria

    2003-09-01

    Fibromyalgia syndrome (FMS) is a disorder with musculoskeletal pain as well as many other psychological and physical symptoms. Up-to-date treatment strategies for this disorder often have only limited effects. In order to develop more effective and adequate treatment tools, a phenomenological-hermeneutic study inspired by Paul Ricoeur was used. FMS patients viewed themselves on videotapes. After the video sessions the FMS patients were interviewed about thoughts that were triggered when they saw themselves on videotape. Video interpretation in combination with interviews facilitated a communication and understanding between the patient and therapist about the patients' body and self-image. The results showed that with the help of video interpretation, the patients' body and self-awareness could be improved, which in turn may help therapists to find better treatment tools for a more directed and individually adapted treatment. This is of importance as this method can be useful to FMS patients for early identification of maladaptive movement patterns and for a better integration their body and self-image. By allowing the FMS patients to interpret themselves from videotape, the FMS patients become more aware of both body and self-signals, which make it easier for the clinician/therapist to know where to start to work with each patients' specific rehabilitation programme.

  12. Postnatal counseling on exclusive breastfeeding using video - experience from a tertiary care teaching hospital, south India.

    Science.gov (United States)

    Adhisivam, B; Vishnu Bhat, B; Poorna, Rachel; Thulasingam, Mahalakshmy; Pournami, Femitha; Joy, Rojo

    2017-04-01

    Adequate antenatal counseling combined with postnatal lactation support is likely to improve exclusive breastfeeding rates. To assess the impact of a postnatal video based health education program in promoting exclusive breastfeeding among primiparous mothers. This interventional study was done in a tertiary care teaching hospital, south India. Primiparous mothers in one postnatal ward (group A) received routine lactation counseling. A similar group of primiparous mothers in another postnatal ward (group B) were administered a video based health education program on exclusive breastfeeding in the local language Tamil in addition to the routine lactation counseling. The exclusive breastfeeding rates of these two groups of mothers were compared. Their knowledge and perceptions after intervention were also compared using a pretested questionnaire. Among 878 primiparous mothers, 94% fed colostrum and 43% initiated breastfeeding within one hour of delivery. Correct attachment was noted with 96% and 13% had lactation issues. Group B had marginally better exclusive breastfeeding rate at six months but not statistically significant. Mothers in group B had a statistically significant better knowledge score post-intervention compared to those in Group A. Use of gripe water was more in group A compared to group B. The video based health education program when combined with routine lactation counseling improved the knowledge regarding exclusive breastfeeding among postnatal primiparous mothers better than with routine lactation counseling alone. However, both interventions had similar effect on exclusive breastfeeding rate at six months.

  13. Telemetry and Communication IP Video Player

    Science.gov (United States)

    OFarrell, Zachary L.

    2011-01-01

    Aegis Video Player is the name of the video over IP system for the Telemetry and Communications group of the Launch Services Program. Aegis' purpose is to display video streamed over a network connection to be viewed during launches. To accomplish this task, a VLC ActiveX plug-in was used in C# to provide the basic capabilities of video streaming. The program was then customized to be used during launches. The VLC plug-in can be configured programmatically to display a single stream, but for this project multiple streams needed to be accessed. To accomplish this, an easy to use, informative menu system was added to the program to enable users to quickly switch between videos. Other features were added to make the player more useful, such as watching multiple videos and watching a video in full screen.

  14. Automatic Story Segmentation for TV News Video Using Multiple Modalities

    Directory of Open Access Journals (Sweden)

    Émilie Dumont

    2012-01-01

    Full Text Available While video content is often stored in rather large files or broadcasted in continuous streams, users are often interested in retrieving only a particular passage on a topic of interest to them. It is, therefore, necessary to split video documents or streams into shorter segments corresponding to appropriate retrieval units. We propose here a method for the automatic segmentation of TV news videos into stories. A-multiple-descriptor based segmentation approach is proposed. The selected multimodal features are complementary and give good insights about story boundaries. Once extracted, these features are expanded with a local temporal context and combined by an early fusion process. The story boundaries are then predicted using machine learning techniques. We investigate the system by experiments conducted using TRECVID 2003 data and protocol of the story boundary detection task, and we show that the proposed approach outperforms the state-of-the-art methods while requiring a very small amount of manual annotation.

  15. Fair Play: A Study of Scientific Workforce Trainers' Experience Playing an Educational Video Game about Racial Bias.

    Science.gov (United States)

    Kaatz, Anna; Carnes, Molly; Gutierrez, Belinda; Savoy, Julia; Samuel, Clem; Filut, Amarette; Pribbenow, Christine Maidl

    2017-01-01

    Explicit racial bias has decreased in the United States, but racial stereotypes still exist and conspire in multiple ways to perpetuate the underparticipation of Blacks in science careers. Capitalizing on the potential effectiveness of role-playing video games to promote the type of active learning required to increase awareness of and reduce subtle racial bias, we developed the video game Fair Play, in which players take on the role of Jamal, a Black male graduate student in science, who experiences discrimination in his PhD program. We describe a mixed-methods evaluation of the experience of scientific workforce trainers who played Fair Play at the National Institutes of Health Division of Training Workforce Development and Diversity program directors' meeting in 2013 (n = 47; 76% female, n = 34; 53% nonwhite, n = 26). The evaluation findings suggest that Fair Play can promote perspective taking and increase bias literacy, which are steps toward reducing racial bias and affording Blacks equal opportunities to excel in science. © 2017 A. Kaatz et al. CBE—Life Sciences Education © 2017 The American Society for Cell Biology. This article is distributed by The American Society for Cell Biology under license from the author(s). It is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

  16. Fair Play: A Study of Scientific Workforce Trainers’ Experience Playing an Educational Video Game about Racial Bias

    Science.gov (United States)

    Kaatz, Anna; Carnes, Molly; Gutierrez, Belinda; Savoy, Julia; Samuel, Clem; Filut, Amarette; Pribbenow, Christine Maidl

    2017-01-01

    Explicit racial bias has decreased in the United States, but racial stereotypes still exist and conspire in multiple ways to perpetuate the underparticipation of Blacks in science careers. Capitalizing on the potential effectiveness of role-playing video games to promote the type of active learning required to increase awareness of and reduce subtle racial bias, we developed the video game Fair Play, in which players take on the role of Jamal, a Black male graduate student in science, who experiences discrimination in his PhD program. We describe a mixed-methods evaluation of the experience of scientific workforce trainers who played Fair Play at the National Institutes of Health Division of Training Workforce Development and Diversity program directors’ meeting in 2013 (n = 47; 76% female, n = 34; 53% nonwhite, n = 26). The evaluation findings suggest that Fair Play can promote perspective taking and increase bias literacy, which are steps toward reducing racial bias and affording Blacks equal opportunities to excel in science. PMID:28450447

  17. Improving Peer-to-Peer Video Systems

    NARCIS (Netherlands)

    Petrocco, R.P.

    2016-01-01

    Video Streaming is nowadays the Internet’s biggest source of consumer traffic. Traditional content providers rely on centralised client-server model for distributing their video streaming content. The current generation is moving from being passive viewers, or content consumers, to active content

  18. Are gamers better crossers? An examination of action video game experience and dual task effects in a simulated street crossing task.

    Science.gov (United States)

    Gaspar, John G; Neider, Mark B; Crowell, James A; Lutz, Aubrey; Kaczmarski, Henry; Kramer, Arthur F

    2014-05-01

    A high-fidelity street crossing simulator was used to test the hypothesis that experienced action video game players are less vulnerable than non-gamers to dual task costs in complex tasks. Previous research has shown that action video game players outperform nonplayers on many single task measures of perception and attention. It is unclear, however, whether action video game players outperform nonplayers in complex, divided attention tasks. Experienced action video game players and nongamers completed a street crossing task in a high-fidelity simulator. Participants walked on a manual treadmill to cross the street. During some crossings, a cognitively demanding working memory task was added. Dividing attention resulted in more collisions and increased decision making time. Of importance, these dual task costs were equivalent for the action video game players and the nongamers. These results suggest that action video game players are equally susceptible to the costs of dividing attention in a complex task. Perceptual and attentional benefits associated with action video game experience may not translate to performance benefits in complex, real-world tasks.

  19. A Robust Streaming Media System

    Science.gov (United States)

    Youwei, Zhang

    Presently, application layer multicast protocols (ALM) are proposed as substitute for IP multicast and have made extraordinary achievements. Integrated with Multi-data-stream mode such as Multiple Description Coding (MDC), ALM becomes more scalable and robust in high-dynamic Internet environment compared with single data stream. Although MDC can provide a flexible data transmission style, the synchronization of different descriptions encoded from one video source is proved to be difficult due to different delay on diverse transmission paths. In this paper, an ALM system called HMDC is proposed to improve accepted video quality of streaming media, hosts can join the separate overlay trees in different layers simultaneously, then the maximum synchronized descriptions of the same layer are worked out to acquire the best video quality. Simulations implemented on Internet-like topology indicate that HMDC achieves better video quality, lower link stress, higher robustness and comparable latency compared with traditional ALM protocols.

  20. Design of video interface conversion system based on FPGA

    Science.gov (United States)

    Zhao, Heng; Wang, Xiang-jun

    2014-11-01

    This paper presents a FPGA based video interface conversion system that enables the inter-conversion between digital and analog video. Cyclone IV series EP4CE22F17C chip from Altera Corporation is used as the main video processing chip, and single-chip is used as the information interaction control unit between FPGA and PC. The system is able to encode/decode messages from the PC. Technologies including video decoding/encoding circuits, bus communication protocol, data stream de-interleaving and de-interlacing, color space conversion and the Camera Link timing generator module of FPGA are introduced. The system converts Composite Video Broadcast Signal (CVBS) from the CCD camera into Low Voltage Differential Signaling (LVDS), which will be collected by the video processing unit with Camera Link interface. The processed video signals will then be inputted to system output board and displayed on the monitor.The current experiment shows that it can achieve high-quality video conversion with minimum board size.

  1. Healthcare Managers' Experiences of Leading the Implementation of Video Conferencing in Discharge Planning Sessions: An Interview Study.

    Science.gov (United States)

    Hofflander, Malin; Nilsson, Lina; Eriksén, Sara; Borg, Christel

    2016-03-01

    This article describes healthcare managers' experiences of leading the implementation of video conferencing in discharge planning sessions as a new tool in everyday practice. Data collection took place through individual interviews and the interviews were analyzed using qualitative content analysis with an inductive approach. The results indicate that managers identified two distinct leadership perspectives when they reflected on the implementation process. They described a desired way of leading the implementation and communicating about the upcoming change, understanding and securing support for decisions, as well as ensuring that sufficient time is available throughout the change process. They also, however, described how they perceived that the implementation process was actually taking place, highlighting the lack of planning and preparation as well as the need for support and to be supportive, and having the courage to adopt and lead the implementation. It is suggested that managers at all levels require more information and training in how to encourage staff to become involved in designing their everyday work and in the implementation process. Managers, too, need ongoing organizational support for good leadership throughout the implementation of video conferencing in discharge planning sessions, including planning, start-up, implementation, and evaluation.

  2. A global experiment suggests climate warming will not accelerate litter decomposition in streams but might reduce carbon sequestration.

    Science.gov (United States)

    Boyero, Luz; Pearson, Richard G; Gessner, Mark O; Barmuta, Leon A; Ferreira, Verónica; Graça, Manuel A S; Dudgeon, David; Boulton, Andrew J; Callisto, Marcos; Chauvet, Eric; Helson, Julie E; Bruder, Andreas; Albariño, Ricardo J; Yule, Catherine M; Arunachalam, Muthukumarasamy; Davies, Judy N; Figueroa, Ricardo; Flecker, Alexander S; Ramírez, Alonso; Death, Russell G; Iwata, Tomoya; Mathooko, Jude M; Mathuriau, Catherine; Gonçalves, José F; Moretti, Marcelo S; Jinggut, Tajang; Lamothe, Sylvain; M'Erimba, Charles; Ratnarajah, Lavenia; Schindler, Markus H; Castela, José; Buria, Leonardo M; Cornejo, Aydeé; Villanueva, Verónica D; West, Derek C

    2011-03-01

    The decomposition of plant litter is one of the most important ecosystem processes in the biosphere and is particularly sensitive to climate warming. Aquatic ecosystems are well suited to studying warming effects on decomposition because the otherwise confounding influence of moisture is constant. By using a latitudinal temperature gradient in an unprecedented global experiment in streams, we found that climate warming will likely hasten microbial litter decomposition and produce an equivalent decline in detritivore-mediated decomposition rates. As a result, overall decomposition rates should remain unchanged. Nevertheless, the process would be profoundly altered, because the shift in importance from detritivores to microbes in warm climates would likely increase CO(2) production and decrease the generation and sequestration of recalcitrant organic particles. In view of recent estimates showing that inland waters are a significant component of the global carbon cycle, this implies consequences for global biogeochemistry and a possible positive climate feedback. © 2011 Blackwell Publishing Ltd/CNRS.

  3. Morphodynamics of semi-alluvial streams in northern Fennoscandia: a flume experiment to determine bedform self-organization

    Science.gov (United States)

    Polvi, Lina

    2017-04-01

    Streams in northern Fennoscandia have two characteristics that complicate a process-based understanding of sediment transport affecting channel form: (1) they are typically semi-alluvial, in that they contain coarse glacial legacy sediment, and (2) numerous mainstem lakes buffer sediment and water fluxes. Systematic studies of these streams are complicated because natural reference sites are lacking due to over a century of widespread channel simplification to aid timber-floating. This research is part of a larger project to determine controls on channel geometry and sediment transport at: (1) the catchment scale, examining downstream hydraulic geometry, (2) the reach scale, examining sediment transport, and (3) the bedform scale, examining the potential for predictable bedform formation. The objective of the current study, targeting the bedform scale, was to use a flume experiment to determine whether sediment self-organizes and creates bedforms in semi-alluvial channels. The prototype channels, tributaries to the unregulated Vindel River in northern Sweden that are being restored after timber-floating, contain coarse sediment (D16: 55 mm, D50:250 mm, D84:620 mm) with moderately steep slopes (2-5%) and typically experience snowmelt-flooding and flooding due to ice jams. Using a scaling factor of 8 for Froude number similitude, an 8-m long, 1.1 m wide fixed-bed flume was set up at the Colorado State University Engineering Research Center with a scaled-down sediment distribution analogous to the prototype channels. For two flume setups, with bed slopes of 2% and 5%, four runs were conducted with flows analogous to QBF, Q2, Q10 and Q50 flows in the prototype channels until equilibrium conditions were reached. Digital elevation models (DEMs) of bed topography were constructed before and after each run using structure-from-motion photogrammetry. To examine self-organization of sediment, DEMs of difference between pre-flow conditions and after each flow were created

  4. Deriving video content type from HEVC bitstream semantics

    Science.gov (United States)

    Nightingale, James; Wang, Qi; Grecos, Christos; Goma, Sergio R.

    2014-05-01

    As network service providers seek to improve customer satisfaction and retention levels, they are increasingly moving from traditional quality of service (QoS) driven delivery models to customer-centred quality of experience (QoE) delivery models. QoS models only consider metrics derived from the network however, QoE models also consider metrics derived from within the video sequence itself. Various spatial and temporal characteristics of a video sequence have been proposed, both individually and in combination, to derive methods of classifying video content either on a continuous scale or as a set of discrete classes. QoE models can be divided into three broad categories, full reference, reduced reference and no-reference models. Due to the need to have the original video available at the client for comparison, full reference metrics are of limited practical value in adaptive real-time video applications. Reduced reference metrics often require metadata to be transmitted with the bitstream, while no-reference metrics typically operate in the decompressed domain at the client side and require significant processing to extract spatial and temporal features. This paper proposes a heuristic, no-reference approach to video content classification which is specific to HEVC encoded bitstreams. The HEVC encoder already makes use of spatial characteristics to determine partitioning of coding units and temporal characteristics to determine the splitting of prediction units. We derive a function which approximates the spatio-temporal characteristics of the video sequence by using the weighted averages of the depth at which the coding unit quadtree is split and the prediction mode decision made by the encoder to estimate spatial and temporal characteristics respectively. Since the video content type of a sequence is determined by using high level information parsed from the video stream, spatio-temporal characteristics are identified without the need for full decoding and can

  5. Evaluation of Distance Education System for Adult Education Using 4 Video Transmissions

    OpenAIRE

    渡部, 和雄; 湯瀬, 裕昭; 渡邉, 貴之; 井口, 真彦; 藤田, 広一

    2004-01-01

    The authors have developed a distance education system for interactive education which can transmit 4 video streams between distant lecture rooms. In this paper, we describe the results of our experiments using the system for adult education. We propose some efficient ways to use the system for adult education.

  6. Anatomic pulmonary resection by video-assisted thoracoscopy: the Brazilian experience (VATS Brazil study).

    Science.gov (United States)

    Terra, Ricardo Mingarini; Kazantzis, Thamara; Pinto-Filho, Darcy Ribeiro; Camargo, Spencer Marcantonio; Martins-Neto, Francisco; Guimarães, Anderson Nassar; Araújo, Carlos Alberto; Losso, Luis Carlos; Ghefter, Mario Claudio; Lima, Nuno Ferreira de; Gomes-Neto, Antero; Brito-Filho, Flávio; Haddad, Rui; Saueressig, Maurício Guidi; Lima, Alexandre Marcelo Rodrigues; Siqueira, Rafael Pontes de; Pinho, Astunaldo Júnior de Macedo E; Vannucci, Fernando

    2016-01-01

    The objective of this study was to describe the results of anatomic pulmonary resections performed by video-assisted thoracoscopy in Brazil. Thoracic surgeons (members of the Brazilian Society of Thoracic Surgery) were invited, via e-mail, to participate in the study. Eighteen surgeons participated in the project by providing us with retrospective databases containing information related to anatomic pulmonary resections performed by video-assisted thoracoscopy. Demographic, surgical, and postoperative data were collected with a standardized instrument, after which they were compiled and analyzed. The surgeons provided data related to a collective total of 786 patients (mean number of resections per surgeon, 43.6). However, 137 patients were excluded because some data were missing. Therefore, the study sample comprised 649 patients. The mean age of the patients was 61.7 years. Of the 649 patients, 295 (45.5%) were male. The majority-521 (89.8%)-had undergone surgery for neoplasia, which was most often classified as stage IA. The median duration of pleural drainage was 3 days, and the median hospital stay was 4 days. Of the 649 procedures evaluated, 598 (91.2%) were lobectomies. Conversion to thoracotomy was necessary in 30 cases (4.6%). Postoperative complications occurred in 124 patients (19.1%), the most common complications being pneumonia, prolonged air leaks, and atelectasis. The 30-day mortality rate was 2.0%, advanced age and diabetes being found to be predictors of mortality. Our analysis of this representative sample of patients undergoing pulmonary resection by video-assisted thoracoscopy in Brazil showed that the procedure is practicable and safe, as well as being comparable to those performed in other countries. O objetivo deste estudo foi descrever os resultados de ressecções pulmonares anatômicas por videotoracoscopia no Brasil. Cirurgiões torácicos (membros da Sociedade Brasileira de Cirurgia Torácica) foram convidados, por correio eletr

  7. Clinical Experience with the PillCam Patency Capsule prior to Video Capsule Endoscopy: A Real-World Experience

    Directory of Open Access Journals (Sweden)

    C. Römmele

    2016-01-01

    Full Text Available Background. In patients with known or suspected risk factors for gastrointestinal stenosis, the PillCam patency capsule (PC is given before a video capsule endoscopy (VCE in order to minimize the risk of capsule retention (CR. CR is considered unlikely upon excretion of the PC within 30 hours, excretion in an undamaged state after 30 hours, or radiological projection to the colon. Methods. We performed a retrospective analysis of 38 patients with risk factors for CR, who received a PC from 02/2013 to 04/2015 at Klinikum Augsburg. Results. Sixteen of our 38 patients observed a natural excretion after a mean time of 34 hours past ingestion. However, only 8 patients observed excretion within 30 hours, as recommended by the company. In 20 patients passage of the PC into the colon was shown via RFID-scan or radiological imaging (after 33 and 45 hours, resp.. Only 2 patients showed a pathologic PC result. In consequence, 32 patients received the VCE; no CR was observed. Conclusion. Our data indicates that a VCE could safely be performed even if the PC excretion time is longer than 30 hours and the excreted PC was not screened for damage.

  8. Efficient Power Allocation for Video over Superposition Coding

    KAUST Repository

    Lau, Chun Pong

    2013-03-01

    In this paper we consider a wireless multimedia system by mapping scalable video coded (SVC) bit stream upon superposition coded (SPC) signals, referred to as (SVC-SPC) architecture. Empirical experiments using a software-defined radio(SDR) emulator are conducted to gain a better understanding of its efficiency, specifically, the impact of the received signal due to different power allocation ratios. Our experimental results show that to maintain high video quality, the power allocated to the base layer should be approximately four times higher than the power allocated to the enhancement layer.

  9. Do Motion Controllers Make Action Video Games Less Sedentary? A Randomized Experiment

    Science.gov (United States)

    Lyons, Elizabeth J.; Tate, Deborah F.; Ward, Dianne S.; Ribisl, Kurt M.; Bowling, J. Michael; Kalyanaraman, Sriram

    2012-01-01

    Sports- and fitness-themed video games using motion controllers have been found to produce physical activity. It is possible that motion controllers may also enhance energy expenditure when applied to more sedentary games such as action games. Young adults (N = 100) were randomized to play three games using either motion-based or traditional controllers. No main effect was found for controller or game pair (P > .12). An interaction was found such that in one pair, motion control (mean [SD] 0.96 [0.20] kcal · kg−1 · hr−1) produced 0.10 kcal · kg−1 · hr−1 (95% confidence interval 0.03 to 0.17) greater energy expenditure than traditional control (0.86 [0.17] kcal · kg−1 · hr−1, P = .048). All games were sedentary. As currently implemented, motion control is unlikely to produce moderate intensity physical activity in action games. However, some games produce small but significant increases in energy expenditure, which may benefit health by decreasing sedentary behavior. PMID:22028959

  10. Video-assisted thoracoscopic surgical decortication in the elderly with thoracic empyema: Five years' experience.

    Science.gov (United States)

    Tsai, Chien-Ho; Lai, Yi-Chun; Chang, Shih-Chieh; Chang, Cheng-Yu; Wang, Wei-Shu; Yuan, Mei-Kang

    2016-01-01

    Video-assisted thoracoscopic surgery (VATS) with decortication is a major treatment for thoracic empyema in the fibropurulent stage. Compared to open thoracotomy, VATS decortication has similar efficacy but fewer postoperative complications in the treatment of thoracic empyema. The role of VATS decortication in the elderly had rarely been investigated. From January 2006 to August 2011, we retrospectively enrolled 33 patients older than 65 years diagnosed as thoracic empyema and treated with VATS decortication. We analyzed the outcomes of this geriatric population, including surgical effectiveness, postoperative morbidity, and mortality. A total of 33 patients with mean age of 73.6 ± 7.1 years received VATS decortication for their empyema. Twenty-one (63.6%) patients were male. Only one patient died of progressive sepsis, due to pulmonary infection 9 days after VATS decortication. The 30-day mortality was 3% after the surgery. The major etiology (87.9%) of thoracic empyema was pneumonia. The main causes of postoperation morbidity included respiratory failure requiring mechanical ventilation for >7 days (15.2%) and septic shock (15.2%), followed by persistent air leakage for >7 days (9.1%). Twenty-four (75%) of 32 patients had good re-expansion of the affected lung 3 months after VATS decortication. We concluded that VATS decortication in the treatment of thoracic empyema is effective in elderly patients. The major concerns of postoperative complications are respiratory failure and sepsis. Copyright © 2015. Published by Elsevier Taiwan LLC.

  11. Do Motion Controllers Make Action Video Games Less Sedentary? A Randomized Experiment

    Directory of Open Access Journals (Sweden)

    Elizabeth J. Lyons

    2012-01-01

    Full Text Available Sports- and fitness-themed video games using motion controllers have been found to produce physical activity. It is possible that motion controllers may also enhance energy expenditure when applied to more sedentary games such as action games. Young adults (N = 100 were randomized to play three games using either motion-based or traditional controllers. No main effect was found for controller or game pair (P > .12. An interaction was found such that in one pair, motion control (mean [SD] 0.96 [0.20] kcal ⋅ kg-1 ⋅ hr-1 produced 0.10 kcal ⋅ kg-1 ⋅ hr-1 (95% confidence interval 0.03 to 0.17 greater energy expenditure than traditional control (0.86 [0.17] kcal ⋅ kg-1 ⋅ hr-1, P = .048. All games were sedentary. As currently implemented, motion control is unlikely to produce moderate intensity physical activity in action games. However, some games produce small but significant increases in energy expenditure, which may benefit health by decreasing sedentary behavior.

  12. Do motion controllers make action video games less sedentary? A randomized experiment.

    Science.gov (United States)

    Lyons, Elizabeth J; Tate, Deborah F; Ward, Dianne S; Ribisl, Kurt M; Bowling, J Michael; Kalyanaraman, Sriram

    2012-01-01

    Sports- and fitness-themed video games using motion controllers have been found to produce physical activity. It is possible that motion controllers may also enhance energy expenditure when applied to more sedentary games such as action games. Young adults (N = 100) were randomized to play three games using either motion-based or traditional controllers. No main effect was found for controller or game pair (P > .12). An interaction was found such that in one pair, motion control (mean [SD] 0.96 [0.20] kcal · kg(-1) · hr(-1)) produced 0.10 kcal · kg(-1) · hr(-1) (95% confidence interval 0.03 to 0.17) greater energy expenditure than traditional control (0.86 [0.17] kcal · kg(-1) · hr(-1), P = .048). All games were sedentary. As currently implemented, motion control is unlikely to produce moderate intensity physical activity in action games. However, some games produce small but significant increases in energy expenditure, which may benefit health by decreasing sedentary behavior.

  13. AudioMove Video

    DEFF Research Database (Denmark)

    2012-01-01

    Live drawing video experimenting with low tech techniques in the field of sketching and visual sense making. In collaboration with Rune Wehner and Teater Katapult.......Live drawing video experimenting with low tech techniques in the field of sketching and visual sense making. In collaboration with Rune Wehner and Teater Katapult....

  14. Video as a Medium for Sharing Experience. Opportunities to Learn No. 1.

    Science.gov (United States)

    Association for Educational Communications and Technology, Washington, DC.

    Satellite telecasts and videotape are discussed in this two-part paper, which is based on the preliminary experiences of Project BEST (Basic Education Skills through Technology), a dissemination project for communicating about the use of technology in teaching basic skills, and providing functional experience with new information communication…

  15. Video game experience and its influence on visual attention parameters: an investigation using the framework of the Theory of Visual Attention (TVA).

    Science.gov (United States)

    Schubert, Torsten; Finke, Kathrin; Redel, Petra; Kluckow, Steffen; Müller, Hermann; Strobach, Tilo

    2015-05-01

    Experts with video game experience, in contrast to non-experienced persons, are superior in multiple domains of visual attention. However, it is an open question which basic aspects of attention underlie this superiority. We approached this question using the framework of Theory of Visual Attention (TVA) with tools that allowed us to assess various parameters that are related to different visual attention aspects (e.g., perception threshold, processing speed, visual short-term memory storage capacity, top-down control, spatial distribution of attention) and that are measurable on the same experimental basis. In Experiment 1, we found advantages of video game experts in perception threshold and visual processing speed; the latter being restricted to the lower positions of the used computer display. The observed advantages were not significantly moderated by general person-related characteristics such as personality traits, sensation seeking, intelligence, social anxiety, or health status. Experiment 2 tested a potential causal link between the expert advantages and video game practice with an intervention protocol. It found no effects of action video gaming on perception threshold, visual short-term memory storage capacity, iconic memory storage, top-down control, and spatial distribution of attention after 15 days of training. However, observations of a selected improvement of processing speed at the lower positions of the computer screen after video game training and of retest effects are suggestive for limited possibilities to improve basic aspects of visual attention (TVA) with practice. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Layered Wyner-Ziv video coding.

    Science.gov (United States)

    Xu, Qian; Xiong, Zixiang

    2006-12-01

    Following recent theoretical works on successive Wyner-Ziv coding (WZC), we propose a practical layered Wyner-Ziv video coder using the DCT, nested scalar quantization, and irregular LDPC code based Slepian-Wolf coding (or lossless source coding with side information at the decoder). Our main novelty is to use the base layer of a standard scalable video coder (e.g., MPEG-4/H.26L FGS or H.263+) as the decoder side information and perform layered WZC for quality enhancement. Similar to FGS coding, there is no performance difference between layered and monolithic WZC when the enhancement bitstream is generated in our proposed coder. Using an H.26L coded version as the base layer, experiments indicate that WZC gives slightly worse performance than FGS coding when the channel (for both the base and enhancement layers) is noiseless. However, when the channel is noisy, extensive simulations of video transmission over wireless networks conforming to the CDMA2000 1X standard show that H.26L base layer coding plus Wyner-Ziv enhancement layer coding are more robust against channel errors than H.26L FGS coding. These results demonstrate that layered Wyner-Ziv video coding is a promising new technique for video streaming over wireless networks.

  17. Optimized adaptive HTTP streaming for mobile devices

    Science.gov (United States)

    Adzic, Velibor; Kalva, Hari; Furht, Borko

    2011-09-01

    In this paper we present a solution to improve the performance of adaptive HTTP streaming services. The proposed approach uses a content aware method to determine whether switching to a higher bitrate can improve video quality. The proposed solution can be implemented as a new parameter in segment description to enable content switching only in cases with meaningful increase in quality. Results of our experiments show clear advantages of using additional parameter in DASH implementation. The proposed approach enables significant bandwidth savings with minimal decrease in quality. It guarantees optimal path of adaptation in various scenarios that can be beneficial both for network providers and end users.

  18. Collaborative e-learning using streaming video and asynchronous discussion boards to teach the cognitive foundation of medical interviewing: a case study.

    Science.gov (United States)

    Wiecha, John M; Gramling, Robert; Joachim, Phyllis; Vanderschmidt, Hannelore

    2003-01-01

    Advances in electronic technology have created opportunities for new instructional designs of medical curricula. We created and evaluated a 4-week online elective course for medical students to teach the cognitive basis for interviewing skills. Ten students, from 2 medical schools, studied online modules on interviewing concepts and viewed videos illustrating the concepts. They then participated in asynchronous discussion groups designed to reinforce course concepts, stimulate reflective learning, and promote peer learning. In qualitative evaluations, learners reported improvements in self-awareness; increased understanding of interviewing concepts; and benefits of online learning vs face to face learning. Participants reported high levels of satisfaction with online learning and with achievement of course objectives. Self-reported knowledge scores increased significantly from pre-course completion to post-course completion. Online education has significant potential to augment curriculum on the medical interview, particularly among students trained in community settings geographically distant from their academic medical center.

  19. Optimisation du protocole TCP pour le streaming adaptatif sur HTTP

    OpenAIRE

    Ben Ameur, Chiheb

    2015-01-01

    HTTP adaptive streaming (HAS) is a streaming video technique widely used over the Internetfor Video on Demand (VoD) and Live streaming services. It employs Transmission Control Protocol(TCP) as transport protocol and it splits the original video inside the server into segments ofsame duration, called "chunks", that are transcoded into multiple quality levels. The HAS player,on the client side, requests for one chunk each chunk duration and it commonly selects the qualitylevel based on the est...

  20. Representing videos in tangible products

    Science.gov (United States)

    Fageth, Reiner; Weiting, Ralf

    2014-03-01

    Videos can be taken with nearly every camera, digital point and shoot cameras, DSLRs as well as smartphones and more and more with so-called action cameras mounted on sports devices. The implementation of videos while generating QR codes and relevant pictures out of the video stream via a software implementation was contents in last years' paper. This year we present first data about what contents is displayed and how the users represent their videos in printed products, e.g. CEWE PHOTOBOOKS and greeting cards. We report the share of the different video formats used, the number of images extracted out of the video in order to represent the video, the positions in the book and different design strategies compared to regular books.

  1. A Ventral Visual Stream Reading Center Independent of Sensory Modality and Visual Experience

    Directory of Open Access Journals (Sweden)

    Lior Reich

    2011-10-01

    Full Text Available The Visual Word Form Area (VWFA is a ventral-temporal-visual area that develops expertise for visual reading. It encodes letter-strings irrespective of case, font, or location in the visual-field, with striking anatomical reproducibility across individuals. In the blind, reading can be achieved using Braille, with a comparable level-of-expertise to that of sighted readers. We investigated which area plays the role of the VWFA in the blind. One would expect it to be at either parietal or bilateral occipital cortex, reflecting the tactile nature of the task and crossmodal plasticity, respectively. However, according to the notion that brain areas are task specific rather than sensory-modality specific, we predicted recruitment of the left-hemispheric VWFA, identically to the sighted and independent of visual experience. Using fMRI we showed that activation during Braille reading in congenitally blind individuals peaked in the VWFA, with striking anatomical consistency within and between blind and sighted. The VWFA was reading-selective when contrasted to high-level language and low-level sensory controls. Further preliminary results show that the VWFA is selectively activated also when people learn to read in a new language or using a different modality. Thus, the VWFA is a mutlisensory area specialized for reading regardless of visual experience.

  2. Streams with Strahler Stream Order

    Data.gov (United States)

    Minnesota Department of Natural Resources — Stream segments with Strahler stream order values assigned. As of 01/08/08 the linework is from the DNR24K stream coverages and will not match the updated...

  3. CovertCast: Using Live Streaming to Evade Internet Censorship

    National Research Council Canada - National Science Library

    Richard McPherson; Amir Houmansadr; Vitaly Shmatikov

    2016-01-01

    We design, implement, and evaluate CovertCast, a censorship circumvention system that broadcasts the content of popular websites in real-time, encrypted video streams on common live-streaming services such as YouTube...

  4. Streaming potential monitoring and modeling of drainage and imbibition: column and lysimeter experiments

    Science.gov (United States)

    Jougnot, D.; Linde, N.; Ciocca, F.; Lunati, I.

    2010-12-01

    The self-potential (SP) method attracts increasing interest in vadose zone hydrology and soil sciences because of its non-invasive nature and its sensitivity to flow and transport. Electrokinetic behaviour of porous media in two phase flow conditions has been the subject of numerous publications that display diverging views on the origin and on how to best model SP signals. This is partly due to a lack of well-controlled experimental data in partially saturated conditions, but also to the different origins and locations of current sources and that signals measured at a given point results from a superposion of effects in the full system. Furthermore, electrode responses can lead to non-linear SP drift signals that are commonly neglected. Many of the published studies have been interpreted based on very strong assumptions that are unlikely to be satisfied in practice; in particular, effects unrelated to flow processes have generally been ignored. We have conducted well-controlled drainage and imbibition experiments at two different scales: (1) at the laboratory scale we used a 1.5 m sand-filled column (4.2 x 10-3 m3) to monitor SP, pressure, and mass together with the temperature and the relative humidity of the lab; (2) at an intermediate scale we used a 2.5 m high lysimeter (3 m3) filled with a loamy soil. The lysimeter was equipped to monitor SP, electrical resistivity, capillary pressure, water content, and temperature at different depths. The total mass of the lysimeter was monitored with three high precision balances to accurately measure fluxes at lysimeter boundaries. At each experimental scale, we have conducted a series of drainage and imbibition experiments that resulted in high-quality and repetitive SP signals (up to 10 mV) in response to inflow/outflow and to the temporally varying water content distribution (from full saturation to 50 % saturation). We have modeled our experiments with a finite element code based on our current understanding of

  5. Winter Precipitation Classification from Two Dimensional Video Disdrometer Data: Observations from Gcpex and Lpvex Experiments

    Science.gov (United States)

    Huang, G. J.; Chandra, C. V.; Moisseev, D.

    2014-12-01

    The liquid-equivalent snow rate (SR) quantitative precipitation estimation (QPE) using radar (both ground-base and satellite) is very important component of GPM research. Winter storms can have with different type of precipitations such as, pristine ice crystal, sleet, graupel-like snow, rimed and aggregated snow, and each type of precipitations have very different micro-physical properties (e.g. size, density, fall speed, dielectric constant), to estimate SR accurately using radar becomes a challenge. The first step to get a proper estimator from radar observations is the precipitation classification. The form of different winter precipitation relates to the environment especially the temperature and humidity. In addition, the different precipitation type also correspond to different shape and density resulting in different fall speeds. Recent research shows that 2DVD is able to observe winter precipitation successfully. The 2DVD can measure the fall speed of each particle falling into its observing area, and provide the contours from two orthogonal views. It is straight forward to estimate the diameter of snowflake from two views of 2DVD and compute the particle size distribution (PSD). In order to classify the different type of precipitation, we must not only estimate the diameter but also define several geometric features. In this paper we explore a technique to estimate features from the contours of 2D-Video images. In this paper, we analyze observations from two GPM winter campaigns namely, GCPEX and LPVEX. From these data sets , we derive the to get the statistics of fall speed and geometric features developed in this paper. Subsequently these are used to classify winter precipitation into four catalogs, namely rain, sleet, graupel-like snow and fluffy snow (may form by aggregation or aggregation with riming). We apply this procedure to two GCPEx cases which mixed with different type of precipitation in different time interval. Since we are using the

  6. Teaching microsurgery to undergraduate medical students by means of high-definition stereo video microscopy: the Aachen skills lab experience

    Science.gov (United States)

    Ilgner, Justus; Park, Jonas Jae-Hyun; Westhofen, Martin

    2008-02-01

    Introduction: The master plan for innovative medical education established at RWTH Aachen Medical Faculty helped to set up an inter-disciplinary, interactive teaching environment for undergraduate medical students during their clinical course. This study presents our first experience with teaching microsurgery to medical students by means of highdefinition stereo video monitoring. Material and methods: A plastic model created for ear inspection with a handheld otoscope was modified with an exchangeable membrane resembling an eardrum plus a model of the human cochlea. We attached a 1280×1024 HD stereo camera to an operating microscope, whose images were processed online by a PC workstation. The live image was displayed by two LCD projectors @ 1280×720 pixels on a 1,25m rear-projection screen by polarized filters. Each medical student was asked to perform standard otosurgical procedures (paracentesis and insertion of grommets; insertion of a cochlear implant electrode) being guided by the HD stereoscopic video image. Results: Students quickly adopted this method of training, as all attendants shared the same high-definition stereoscopic image. The learning process of coordinating hand movement with visual feedback was regarded being challenging as well as instructive by all students. Watching the same image facilitated valuable feedback from the audience for each student performing his tasks. All students noted that this course made them feel more confident in their manual skills and that they would consider a career in a microsurgical specialty. Conclusion: High definition stereoscopy provides an easy access to microsurgical techniques for undergraduate medical students. This access not only bears the potential to compress the learning curve for junior doctors during their clinical training but also helps to attract medical students to a career in a microsurgical specialty.

  7. Subjective Analysis and Objective Characterization of Adaptive Bitrate Videos

    DEFF Research Database (Denmark)

    Søgaard, Jacob; Tavakoli, Samira; Brunnström, Kjell

    2016-01-01

    The HTTP Adaptive Streaming (HAS) technology allows video service providers to improve the network utilization and thereby increasing the end-users’ Quality of Experience (QoE).This has made HAS a widely used approach for audiovisual delivery. There are several previous studies aiming to identify...... the factors influencing on subjective QoE of adaptation events.However, adapting the video quality typically lasts in a time scale much longer than what current standardized subjective testing methods are designed for, thus making the full matrix design of the experiment on an event level hard to achieve....... In this study, we investigated the overall subjective QoE of 6 minutes long video sequences containing different sequential adaptation events. This was compared to a data set from our previous work performed to evaluate the individual adaptation events. We could then derive a relationship between the overall...

  8. A Fuzzy-Based Adaptive Streaming Algorithm for Reducing Entropy Rate of DASH Bitrate Fluctuation to Improve Mobile Quality of Service

    Directory of Open Access Journals (Sweden)

    Linh Van Ma

    2017-09-01

    Full Text Available Dynamic adaptive streaming over Hypertext Transfer Protocol (HTTP is an advanced technology in video streaming to deal with the uncertainty of network states. However, this technology has one drawback as the network states frequently and continuously change. The quality of a video streaming fluctuates along with the network changes, and it might reduce the quality of service. In recent years, many researchers have proposed several adaptive streaming algorithms to reduce such changes. However, these algorithms only consider the current state of a network. Thus, these algorithms might result in inaccurate estimates of a video quality in the near term. Therefore, in this paper, we propose a method using fuzzy logic and a mathematics moving average technique, in order to reduce mobile video quality fluctuation in Dynamic Adaptive Streaming over HTTP (DASH. First, we calculate the moving average of the bandwidth and buffer values for a given period. On the basis of differences between real and average values, we propose a fuzzy logic system to deduce the value of the video quality representation for the next request. In addition, we use the entropy rate of a bandwidth measurement sequence to measure the predictable/stabilization of our method. The experiment results show that our proposed method reduces video quality fluctuation as well as improves 40% of bandwidth utilization compared to existing methods.

  9. Real behavior in virtual environments: psychology experiments in a simple virtual-reality paradigm using video games.

    Science.gov (United States)

    Kozlov, Michail D; Johansen, Mark K

    2010-12-01

    The purpose of this research was to illustrate the broad usefulness of simple video-game-based virtual environments (VEs) for psychological research on real-world behavior. To this end, this research explored several high-level social phenomena in a simple, inexpensive computer-game environment: the reduced likelihood of helping under time pressure and the bystander effect, which is reduced helping in the presence of bystanders. In the first experiment, participants had to find the exit in a virtual labyrinth under either high or low time pressure. They encountered rooms with and without virtual bystanders, and in each room, a virtual person requested assistance. Participants helped significantly less frequently under time pressure but the presence/absence of a small number of bystanders did not significantly moderate helping. The second experiment increased the number of virtual bystanders, and participants were instructed to imagine that these were real people. Participants helped significantly less in rooms with large numbers of bystanders compared to rooms with no bystanders, thus demonstrating a bystander effect. These results indicate that even sophisticated high-level social behaviors can be observed and experimentally manipulated in simple VEs, thus implying the broad usefulness of this paradigm in psychological research as a good compromise between experimental control and ecological validity.

  10. IMPLEMENTATION OF HTTP LIVE STREAMING PROTOCOL IN JAVA

    OpenAIRE

    Rehar, Anže

    2012-01-01

    In this thesis we discuss protocols for streaming to mobile devices. Tremendous growth of smartphone and tablet sales numbers over the past few years push content providers to seek new ways to offer video content. However, these devices have some limitations that make the implementation of video streaming a complex project. Most depends on the streaming protocol selection. There is a set of HTTP based technologies but there are no standards for adaptive streaming to mobile devices. In thesis ...

  11. Scalable TCP-friendly Video Distribution for Heterogeneous Clients

    Science.gov (United States)

    Zink, Michael; Griwodz, Carsten; Schmitt, Jens; Steinmetz, Ralf

    2003-01-01

    This paper investigates an architecture and implementation for the use of a TCP-friendly protocol in a scalable video distribution system for hierarchically encoded layered video. The design supports a variety of heterogeneous clients, because recent developments have shown that access network and client capabilities differ widely in today's Internet. The distribution system presented here consists of videos servers, proxy caches and clients that make use of a TCP-friendly rate control (TFRC) to perform congestion controlled streaming of layer encoded video. The data transfer protocol of the system is RTP compliant, yet it integrates protocol elements for congestion control with protocols elements for retransmission that is necessary for lossless transfer of contents into proxy caches. The control protocol RTSP is used to negotiate capabilities, such as support for congestion control or retransmission. By tests performed with our experimental platform in a lab test and over the Internet, we show that congestion controlled streaming of layer encoded video through proxy caches is a valid means of supporting heterogeneous clients. We show that filtering of layers depending on a TFRC-controlled permissible bandwidth allows the preferred delivery of the most relevant layers to end-systems while additional layers can be delivered to the cache server. We experiment with uncontrolled delivery from the proxy cache to the client as well, which may result in random loss and bandwidth waste but also a higher goodput, and compare these two approaches.

  12. Unilateral face-to-face communication in ultimatum bargaining : A video experiment

    OpenAIRE

    Schmidt, Carsten; Zultan, Ro?i

    2004-01-01

    It is commonly accepted that face-to-face communication induces cooperation. The experiment disentangles communication and social effect (replication of Roth, 1995) and examines the components of the social effect with the help of unilateral communication. Results suggest that separate processes, both of a strategic and of an affective-social nature may induce cooperative outcomes in ultimatum bargaining with pre-play communication, depending on the communication protocol. Unilateral communic...

  13. Multiple Feature Fusion Based on Co-Training Approach and Time Regularization for Place Classification in Wearable Video

    Directory of Open Access Journals (Sweden)

    Vladislavs Dovgalecs

    2013-01-01

    Full Text Available The analysis of video acquired with a wearable camera is a challenge that multimedia community is facing with the proliferation of such sensors in various applications. In this paper, we focus on the problem of automatic visual place recognition in a weakly constrained environment, targeting the indexing of video streams by topological place recognition. We propose to combine several machine learning approaches in a time regularized framework for image-based place recognition indoors. The framework combines the power of multiple visual cues and integrates the temporal continuity information of video. We extend it with computationally efficient semisupervised method leveraging unlabeled video sequences for an improved indexing performance. The proposed approach was applied on challenging video corpora. Experiments on a public and a real-world video sequence databases show the gain brought by the different stages of the method.

  14. The effects of action video game experience on the time course of inhibition of return and the efficiency of visual search.

    Science.gov (United States)

    Castel, Alan D; Pratt, Jay; Drummond, Emily

    2005-06-01

    The ability to efficiently search the visual environment is a critical function of the visual system, and recent research has shown that experience playing action video games can influence visual selective attention. The present research examined the similarities and differences between video game players (VGPs) and non-video game players (NVGPs) in terms of the ability to inhibit attention from returning to previously attended locations, and the efficiency of visual search in easy and more demanding search environments. Both groups were equally good at inhibiting the return of attention to previously cued locations, although VGPs displayed overall faster reaction times to detect targets. VGPs also showed overall faster response time for easy and difficult visual search tasks compared to NVGPs, largely attributed to faster stimulus-response mapping. The findings suggest that relative to NVGPs, VGPs rely on similar types of visual processing strategies but possess faster stimulus-response mappings in visual attention tasks.

  15. Students' Perceptions of the Value of Using Videos as a Pre-Class Learning Experience in the Flipped Classroom

    Science.gov (United States)

    Long, Taotao; Logan, Joanne; Waugh, Michael

    2016-01-01

    The flipped classroom is an instructional model in which students viewed the learning content before class through instructor-provided video lectures or other pre-class learning materials, and in-class time is used for student-centered active learning. Video is widely utilized as a typical pre-class learning material in the flipped classroom. This…

  16. Is that really my movement?—Students' experiences of a video-supported interactive learning model for movement awareness

    Science.gov (United States)

    Backåberg, Sofia; Gummesson, Christina; Brunt, David; Rask, Mikael

    2015-01-01

    Healthcare staff and students have a great risk of developing musculoskeletal symptoms. One cause of this is heavy load related work activities such as manual handling, in which the quality of individual work technique may play a major role. Preventive interventions and well-defined educational strategies to support movement awareness and long-lasting movement changes need to be developed. The aim of the present study was to explore nursing students’ experiences of a newly developed interactive learning model for movement awareness. The learning model, which is based on a life-world perspective with focus on interpersonal interaction, has been used with 11 undergraduate students from the second and final year. Each student participated in three individual video sessions with a facilitator. Two individual interviews were carried out with each student during the learning process and one interview 12–18 months after the last session. The interviews were audio-recorded and transcribed verbatim, and a phenomenological hermeneutic method inspired by Paul Ricoeur and described by Lindseth and Norberg was used to interpret the interviews and diary notes. The interpretation resulted in three key themes and nine subthemes. The key themes were; “Obtaining better preconditions for bodily awareness,” “Experiencing changes in one's own movement,” and “Experiencing challenges in the learning process.” The interactive learning model entails a powerful and challenging experience that develops movement awareness. The experience of meaningfulness and usefulness emerges increasingly and alternates with a feeling of discomfort. The learning model may contribute to the body of knowledge of well-defined educational strategies in movement awareness and learning in, for example, preventive interventions and ergonomic education. It may also be valuable in other practical learning situations where movement awareness is required. PMID:26274385

  17. Is that really my movement? - Students' experiences of a video-supported interactive learning model for movement awareness.

    Science.gov (United States)

    Backåberg, Sofia; Gummesson, Christina; Brunt, David; Rask, Mikael

    2015-01-01

    Healthcare staff and students have a great risk of developing musculoskeletal symptoms. One cause of this is heavy load related work activities such as manual handling, in which the quality of individual work technique may play a major role. Preventive interventions and well-defined educational strategies to support movement awareness and long-lasting movement changes need to be developed. The aim of the present study was to explore nursing students' experiences of a newly developed interactive learning model for movement awareness. The learning model, which is based on a life-world perspective with focus on interpersonal interaction, has been used with 11 undergraduate students from the second and final year. Each student participated in three individual video sessions with a facilitator. Two individual interviews were carried out with each student during the learning process and one interview 12-18 months after the last session. The interviews were audio-recorded and transcribed verbatim, and a phenomenological hermeneutic method inspired by Paul Ricoeur and described by Lindseth and Norberg was used to interpret the interviews and diary notes. The interpretation resulted in three key themes and nine subthemes. The key themes were; "Obtaining better preconditions for bodily awareness," "Experiencing changes in one's own movement," and "Experiencing challenges in the learning process." The interactive learning model entails a powerful and challenging experience that develops movement awareness. The experience of meaningfulness and usefulness emerges increasingly and alternates with a feeling of discomfort. The learning model may contribute to the body of knowledge of well-defined educational strategies in movement awareness and learning in, for example, preventive interventions and ergonomic education. It may also be valuable in other practical learning situations where movement awareness is required.

  18. Content-based TV sports video retrieval using multimodal analysis

    Science.gov (United States)

    Yu, Yiqing; Liu, Huayong; Wang, Hongbin; Zhou, Dongru

    2003-09-01

    In this paper, we propose content-based video retrieval, which is a kind of retrieval by its semantical contents. Because video data is composed of multimodal information streams such as video, auditory and textual streams, we describe a strategy of using multimodal analysis for automatic parsing sports video. The paper first defines the basic structure of sports video database system, and then introduces a new approach that integrates visual stream analysis, speech recognition, speech signal processing and text extraction to realize video retrieval. The experimental results for TV sports video of football games indicate that the multimodal analysis is effective for video retrieval by quickly browsing tree-like video clips or inputting keywords within predefined domain.

  19. Initial experience at a university teaching hospital from using telemedicine to promote education through video conferencing

    Directory of Open Access Journals (Sweden)

    Bruno Monteiro Tavares Pereira

    Full Text Available CONTEXT AND OBJECTIVE: Telehealth and telemedicine services are advancing rapidly, with an increasing spectrum of information and communication technologies that can be applied broadly to the population's health, and to medical education. The aim here was to report our institution's experience from 100 videoconferencing meetings between five different countries in the Americas over a one-year period. DESIGN AND SETTING: Retrospective study at Universidade Estadual de Campinas. METHODS: Through a Microsoft Excel database, all conferences in all specialties held at our institution from September 2009 to August 2010 were analyzed retrospectively. RESULTS: A total of 647 students, physicians and professors participated in telemedicine meetings. A monthly mean of 8.3 (± 4.3 teleconferences were held over the analysis period. Excluding holidays and the month of inaugurating the telemedicine theatre, our teleconference rate reached a mean of 10.3 (± 2.7, or two teleconferences a week, on average. Trauma surgery and meetings on patient safety were by far the most common subjects discussed in our teleconference meetings, accounting for 22% and 21% of the total calls. CONCLUSION: Our experience with telemedicine meetings has increased students' interest; helped our institution to follow and discuss protocols that are already accepted worldwide; and stimulated professors to promote telemedicine-related research in their own specialties and keep up-to-date. These high-technology meetings have shortened distances in our vast country, and to other reference centers abroad. This virtual proximity has enabled discussion of international training with students and residents, to increase their overall knowledge and improve their education within this institution.

  20. A Predictive Study of Learner Satisfaction and Outcomes in Face-to-Face, Satellite Broadcast, and Live Video-Streaming Learning Environments

    Science.gov (United States)

    Abdous, M'hammed; Yen, Cherng-Jyh

    2010-01-01

    This study was conducted to assess the predictive relationships among delivery mode (DM), self-perceived learner-to-teacher interaction, self-rated computer skill, prior distance learning experience, and learners' satisfaction and outcomes. Participants were enrolled in courses which used three different DMs: face-to-face, satellite broadcasting,…

  1. Traffic Management of Video on Demand: An Analysis of Investments for Improving the End User’s Quality of Experience

    Directory of Open Access Journals (Sweden)

    Francesca Di Pillo

    2016-05-01

    Full Text Available The current escalation in user demand for web contents, particularly Video on Demand (VoD, is causing a continu‐ ing increase in both the types of web traffic and the volumes of data transmitted. The greater demand arises from the new means of communication employed by individuals and companies, as well as the development of readily usable applications distributed by ‘app stores’. In this paper, we suggest that the stakeholders of a VoD frame‐ work, the Content Providers (CPs and the Internet Service Providers (telcos/ISPs, should guarantee a solid Quality of Experience (QoE to the end user through two potential investments: either in ultra-broadband (UBB or in the technologies for the acceleration of web content, known as the Content Delivery Network (CDN and Transparent Internet Caching (TIC. The aim of the paper is to analyse these investments in terms of providers' profits. The base hypothesis is that the investments are subsidized by the CPs, which, in recent years, have indeed been directing a large part of their revenues towards investments in network infrastructure.

  2. Video microblogging

    DEFF Research Database (Denmark)

    Bornoe, Nis; Barkhuus, Louise

    2010-01-01

    Microblogging is a recently popular phenomenon and with the increasing trend for video cameras to be built into mobile phones, a new type of microblogging has entered the arena of electronic communication: video microblogging. In this study we examine video microblogging, which is the broadcasting...... of short videos. A series of semi-structured interviews offers an understanding of why and how video microblogging is used and what the users post and broadcast....

  3. Push-Pull Two-Layer Super-Peer based P2P Live Media Streaming

    Science.gov (United States)

    Hoong, Poo Kuan; Matsuo, Hiroshi

    Peer-to-peer (P2P) file sharing has become increasingly popular, accounting for as much as 70% of Internet traffic by some estimates. Recently, we have been witnessing the emergence of a new class of popular P2P applications, namely, P2P audio and video streaming. In this study, we propose and investigate a full distributed, scalable and cooperative protocol for live video streaming in an overlay peer-to-peer network. Our protocol, termed P2P Super-Peer based Unstructured Live Media Streaming (PALMS-SP), makes use of combination of push-pull scheduling methods to achieve high performance (in term of delay, stream continuity, cooperation, etc.). The main contribution of PALMS-SP is that it reduces the end-to-end streaming delay and in turn results better delivered quality. We have extensively evaluated the performance of PALMS-SP. Our experiments demonstrate that PALMS-SP with the existence of super-peers achieves better streaming quality in comparison with other existing streaming applications.

  4. A video event trigger for high frame rate, high resolution video technology

    Science.gov (United States)

    Williams, Glenn L.

    1991-01-01

    When video replaces film the digitized video data accumulates very rapidly, leading to a difficult and costly data storage problem. One solution exists for cases when the video images represent continuously repetitive 'static scenes' containing negligible activity, occasionally interrupted by short events of interest. Minutes or hours of redundant video frames can be ignored, and not stored, until activity begins. A new, highly parallel digital state machine generates a digital trigger signal at the onset of a video event. High capacity random access memory storage coupled with newly available fuzzy logic devices permits the monitoring of a video image stream for long term or short term changes caused by spatial translation, dilation, appearance, disappearance, or color change in a video object. Pretrigger and post-trigger storage techniques are then adaptable for archiving the digital stream from only the significant video images.

  5. Supporting Seamless Mobility for P2P Live Streaming

    Directory of Open Access Journals (Sweden)

    Eunsam Kim

    2014-01-01

    Full Text Available With advent of various mobile devices with powerful networking and computing capabilities, the users' demand to enjoy live video streaming services such as IPTV with mobile devices has been increasing rapidly. However, it is challenging to get over the degradation of service quality due to data loss caused by the handover. Although many handover schemes were proposed at protocol layers below the application layer, they inherently suffer from data loss while the network is being disconnected during the handover. We therefore propose an efficient application-layer handover scheme to support seamless mobility for P2P live streaming. By simulation experiments, we show that the P2P live streaming system with our proposed handover scheme can improve the playback continuity significantly compared to that without our scheme.

  6. Supporting Seamless Mobility for P2P Live Streaming

    Science.gov (United States)

    Kim, Eunsam; Kim, Sangjin; Lee, Choonhwa

    2014-01-01

    With advent of various mobile devices with powerful networking and computing capabilities, the users' demand to enjoy live video streaming services such as IPTV with mobile devices has been increasing rapidly. However, it is challenging to get over the degradation of service quality due to data loss caused by the handover. Although many handover schemes were proposed at protocol layers below the application layer, they inherently suffer from data loss while the network is being disconnected during the handover. We therefore propose an efficient application-layer handover scheme to support seamless mobility for P2P live streaming. By simulation experiments, we show that the P2P live streaming system with our proposed handover scheme can improve the playback continuity significantly compared to that without our scheme. PMID:24977171

  7. [A new laser scan system for video ophthalmoscopy. Initial clinical experiences also in relation to digital image processing].

    Science.gov (United States)

    Fabian, E; Mertz, M; Hofmann, H; Wertheimer, R; Foos, C

    1990-06-01

    The clinical advantages of a scanning laser ophthalmoscope (SLO) and video imaging of fundus pictures are described. Image quality (contrast, depth of field) and imaging possibilities (confocal stop) are assessed. Imaging with different lasers (argon, He-Ne) and changes in imaging rendered possible by confocal alignment of the imaging optics are discussed. Hard copies from video images are still of inferior quality compared to fundus photographs. Methods of direct processing and retrieval of digitally stored SLO video fundus images are illustrated by examples. Modifications for a definitive laser scanning system - in regard to the field of view and the quality of hard copies - are proposed.

  8. Multi-modal highlight generation for sports videos using an information-theoretic excitability measure

    Science.gov (United States)

    Hasan, Taufiq; Bořil, Hynek; Sangwan, Abhijeet; L Hansen, John H.

    2013-12-01

    The ability to detect and organize `hot spots' representing areas of excitement within video streams is a challenging research problem when techniques rely exclusively on video content. A generic method for sports video highlight selection is presented in this study which leverages both video/image structure as well as audio/speech properties. Processing begins where the video is partitioned into small segments and several multi-modal features are extracted from each segment. Excitability is computed based on the likelihood of the segmental features residing in certain regions of their joint probability density function space which are considered both exciting and rare. The proposed measure is used to rank order the partitioned segments to compress the overall video sequence and produce a contiguous set of highlights. Experiments are performed on baseball videos based on signal processing advancements for excitement assessment in the commentators' speech, audio energy, slow motion replay, scene cut density, and motion activity as features. Detailed analysis on correlation between user excitability and various speech production parameters is conducted and an effective scheme is designed to estimate the excitement level of commentator's speech from the sports videos. Subjective evaluation of excitability and ranking of video segments demonstrate a higher correlation with the proposed measure compared to well-established techniques indicating the effectiveness of the overall approach.

  9. Stream Crossings

    Data.gov (United States)

    Vermont Center for Geographic Information — Physical measurements and attributes of stream crossing structures and adjacent stream reaches which are used to provide a relative rating of aquatic organism...

  10. A blinded assessment of video quality in wearable technology for telementoring in open surgery: the Google Glass experience.

    Science.gov (United States)

    Hashimoto, Daniel A; Phitayakorn, Roy; Fernandez-del Castillo, Carlos; Meireles, Ozanan

    2016-01-01

    The goal of telementoring is to recreate face-to-face encounters with a digital presence. Open-surgery telementoring is limited by lack of surgeon's point-of-view cameras. Google Glass is a wearable computer that looks like a pair of glasses but is equipped with wireless connectivity, a camera, and viewing screen for video conferencing. This study aimed to assess the safety of using Google Glass by assessing the video quality of a telementoring session. Thirty-four (n = 34) surgeons at a single institution were surveyed and blindly compared via video captured with Google Glass versus an Apple iPhone 5 during the open cholecystectomy portion of a Whipple. Surgeons were asked to evaluate the quality of the video and its adequacy for safe use in telementoring. Thirty-four of 107 invited surgical attendings (32%) responded to the anonymous survey. A total of 50% rated the Google Glass video as fair with the other 50% rating it as bad to poor. A total of 52.9% of respondents rated the Apple iPhone video as good. A significantly greater proportion of respondents felt Google Glass video quality was inadequate for telementoring versus the Apple iPhone's (82.4 vs 26.5%, p Google Glass provides a great breadth of functionality as a wearable device with two-way communication capabilities, current hardware limitations prevent its use as a telementoring device in surgery as the video quality is inadequate for safe telementoring. As the device is still in initial phases of development, future iterations or competitor devices may provide a better telementoring application for wearable devices.

  11. Illustrating Geology With Customized Video in Introductory Geoscience Courses

    Science.gov (United States)

    Magloughlin, J. F.

    2008-12-01

    For the past several years, I have been creating short videos for use in large-enrollment introductory physical geology classes. The motivation for this project included 1) lack of appropriate depth in existing videos, 2) engagement of non-science students, 3) student indifference to traditional textbooks, 4) a desire to share the visual splendor of geology through virtual field trips, and 5) a desire to meld photography, animation, narration, and videography in self-contained experiences. These (HD) videos are information-intensive but short, allowing a focus on relatively narrow topics from numerous subdisciplines, incorporation into lectures to help create variety while minimally interrupting flow and holding students' attention, and manageable file sizes. Nearly all involve one or more field locations, including sites throughout the western and central continental U.S., as well as Hawaii, Italy, New Zealand, and Scotland. The limited scope of the project and motivations mentioned preclude a comprehensive treatment of geology. Instead, videos address geologic processes, locations, features, and interactions with humans. The videos have been made available via DVD and on-line streaming. Such a project requires an array of video and audio equipment and software, a broad knowledge of geology, very good computing power, adequate time, creativity, a substantial travel budget, liability insurance, elucidation of the separation (or non-separation) between such a project and other responsibilities, and, preferably but not essentially, the support of one's supervisor or academic unit. Involving students in such projects entails risks, but involving necessary technical expertise is virtually unavoidable. In my own courses, some videos are used in class and/or made available on-line as simply another aspect of the educational experience. Student response has been overwhelmingly positive, particularly when expectations of students regarding the content of the videos is made

  12. Online video examination

    DEFF Research Database (Denmark)

    Qvist, Palle

    courses are accredited to the master programme. The programme is online, worldwide and on demand. It recruits students from all over the world. The programme is organized exemplary in accordance the principles in the problem-based and project-based learning method used at Aalborg University where students......The Master programme in Problem-Based Learning in Engineering and Science, MPBL (www.mpbl.aau.dk), at Aalborg University, is an international programme offering formalized staff development. The programme is also offered in smaller parts as single subject courses (SSC). Passed single subject...... have large influence on their own teaching, learning and curriculum. The programme offers streamed videos in combination with other learning resources. It is a concept which offers video as pure presentation - video lectures - but also as an instructional tool which gives the students the possibility...

  13. MovieRemix: Having Fun Playing with Videos

    Directory of Open Access Journals (Sweden)

    Nicola Dusi

    2011-01-01

    scenario. Known as remix or video remix, the produced video may have new and different meanings with respect to the source material. Unfortunately, when managing audiovisual objects, the technological aspect can be a burden for many creative users. Motivated by the large success of the gaming market, we propose a novel game and an architecture to make the remix process a pleasant and stimulating gaming experience. MovieRemix allows people to act like a movie director, but instead of dealing with cast and cameras, the player has to create a remixed video starting from a given screenplay and from video shots retrieved from the provided catalog. MovieRemix is not a simple video editing tool nor is a simple game: it is a challenging environment that stimulates creativity. To temp to play the game, players can access different levels of screenplay (original, outline, derived and can also challenge other players. Computational and storage issues are kept at the server side, whereas the client device just needs to have the capability of playing streaming videos.

  14. Video as a Means for the Academic Improvement of a Profession

    DEFF Research Database (Denmark)

    Buhl, Mie

    2013-01-01

    Video as a means for learning is a growing field in Danish university education. Different settings that include videos, such as video conferences or video streaming, have been tried out in order to overcome distances between teachers and learners. But video is also used as a means for facilitating...

  15. Interactive media technologies challenges and risks among youth in Sweden. : 11 children’s and 11 parents’ thoughts and experiences about Internet and video games

    OpenAIRE

    Ortiz de Gortari, Angelica; Eltayeb, Rawia

    2009-01-01

    Interactive media technologies like the Internet and video games have opened new avenues of opportunity for many, yet at the same time they represent new challenges and risks, especially for young people. In our study, eleven families were interviewed. Their perceptions, experiences and risk management are described in this paper. The children we interviewed were not high media consumers. The vast majority appeared to have a positive attitude towards the Internet, and had learned to handle co...

  16. Automated analysis and annotation of basketball video

    Science.gov (United States)

    Saur, Drew D.; Tan, Yap-Peng; Kulkarni, Sanjeev R.; Ramadge, Peter J.

    1997-01-01

    Automated analysis and annotation of video sequences are important for digital video libraries, content-based video browsing and data mining projects. A successful video annotation system should provide users with useful video content summary in a reasonable processing time. Given the wide variety of video genres available today, automatically extracting meaningful video content for annotation still remains hard by using current available techniques. However, a wide range video has inherent structure such that some prior knowledge about the video content can be exploited to improve our understanding of the high-level video semantic content. In this paper, we develop tools and techniques for analyzing structured video by using the low-level information available directly from MPEG compressed video. Being able to work directly in the video compressed domain can greatly reduce the processing time and enhance storage efficiency. As a testbed, we have developed a basketball annotation system which combines the low-level information extracted from MPEG stream with the prior knowledge of basketball video structure to provide high level content analysis, annotation and browsing for events such as wide- angle and close-up views, fast breaks, steals, potential shots, number of possessions and possession times. We expect our approach can also be extended to structured video in other domains.

  17. Classification-based Multi-client Video Transmission over Heterogeneous Networks

    OpenAIRE

    Bo Li; Peng Wang; Yongfei Zhang

    2013-01-01

    These Real-time video streaming over networks operates under stringent network resource constraints, with multiple video clients competing for limited network resources. In this paper, we study the problem of bandwidth allocation for video transmission over heterogeneous networks, with multiple video clients connecting to the video server simultaneously and demanding for the video services, and aim to provide the best possible Quality of Service (QoS) under limited bandwidth of both the video...

  18. LHCb trigger streams optimization

    Science.gov (United States)

    Derkach, D.; Kazeev, N.; Neychev, R.; Panin, A.; Trofimov, I.; Ustyuzhanin, A.; Vesterinen, M.

    2017-10-01

    The LHCb experiment stores around 1011 collision events per year. A typical physics analysis deals with a final sample of up to 107 events. Event preselection algorithms (lines) are used for data reduction. Since the data are stored in a format that requires sequential access, the lines are grouped into several output file streams, in order to increase the efficiency of user analysis jobs that read these data. The scheme efficiency heavily depends on the stream composition. By putting similar lines together and balancing the stream sizes it is possible to reduce the overhead. We present a method for finding an optimal stream composition. The method is applied to a part of the LHCb data (Turbo stream) on the stage where it is prepared for user physics analysis. This results in an expected improvement of 15% in the speed of user analysis jobs, and will be applied on data to be recorded in 2017.

  19. Screens of intensification: on DIY concert videos of Lady Gaga and the use of media interfaces as tools of experience intensification

    Directory of Open Access Journals (Sweden)

    Carsten Stage

    2012-06-01

    Full Text Available The article is based on the analysis of user-generated videos from a particular event: the Lady Gaga concert in Denmark on October 20, 2010. Within the theoretical framework of a media practice perspective, theories of a media cultural movement from sign to signal, and an affective understanding of the experience of liveness, I argue that the DIY videos do not only attest to the documentation or representation of the concert event, but rather show an urge to feel it, connect to it, and relate to others by sharing it. In that way media and screens can be understood as technologies that under certain circumstances enable intensified relations between bodies, spaces, and significant others. The experiential intensification of the event is established by using media to (1 visually enrich the real-time experience, (2 turn the collective receiver into an individualized and creative real-time auteur, and (3 deterritorialize the real-time experience by sharing it on social media platforms. Furthermore, I discuss two ways of analyzing “the signal” in my material: one focusing on the relation between body, event, and mobile media technology and the other on the formal features of the videos themselves. This distinction is nevertheless purely analytical given that the formal traces of the signal (the sensory turbulence of the videos are so closely related to the spatially affected camera-body. The body in the space, the camera, and the audiovisual surface is in other words affecting each other, as the signaletic force of the concert-event affects all the three.

  20. Video Synchronization With Bit-Rate Signals and Correntropy Function.

    Science.gov (United States)

    Pereira, Igor; Silveira, Luiz F; Gonçalves, Luiz

    2017-09-04

    We propose an approach for the synchronization of video streams using correntropy. Essentially, the time offset is calculated on the basis of the instantaneous transfer rates of the video streams that are extracted in the form of a univariate signal known as variable bit-rate (VBR). The state-of-the-art approach uses a window segmentation strategy that is based on consensual zero-mean normalized cross-correlation (ZNCC). This strategy has an elevated computational complexity, making its application to synchronizing online data streaming difficult. Hence, our proposal uses a different window strategy that, together with the correntropy function, allows the synchronization to be performed for online applications. This provides equivalent synchronization scores with a rapid offset determination as the streams come into the system. The efficiency of our approach has been verified through experiments that demonstrate its viability with values that are as precise as those obtained by ZNCC. The proposed approach scored 81 % in time reference classification against the equivalent 81 % of the state-of-the-art approach, requiring much less computational power.

  1. Video Synchronization With Bit-Rate Signals and Correntropy Function

    Directory of Open Access Journals (Sweden)

    Igor Pereira

    2017-09-01

    Full Text Available We propose an approach for the synchronization of video streams using correntropy. Essentially, the time offset is calculated on the basis of the instantaneous transfer rates of the video streams that are extracted in the form of a univariate signal known as variable bit-rate (VBR. The state-of-the-art approach uses a window segmentation strategy that is based on consensual zero-mean normalized cross-correlation (ZNCC. This strategy has an elevated computational complexity, making its application to synchronizing online data streaming difficult. Hence, our proposal uses a different window strategy that, together with the correntropy function, allows the synchronization to be performed for online applications. This provides equivalent synchronization scores with a rapid offset determination as the streams come into the system. The efficiency of our approach has been verified through experiments that demonstrate its viability with values that are as precise as those obtained by ZNCC. The proposed approach scored 81 % in time reference classification against the equivalent 81 % of the state-of-the-art approach, requiring much less computational power.

  2. Social video content delivery

    CERN Document Server

    Wang, Zhi; Zhu, Wenwu

    2016-01-01

    This brief presents new architecture and strategies for distribution of social video content. A primary framework for socially-aware video delivery and a thorough overview of the possible approaches is provided. The book identifies the unique characteristics of socially-aware video access and social content propagation, revealing the design and integration of individual modules that are aimed at enhancing user experience in the social network context. The change in video content generation, propagation, and consumption for online social networks, has significantly challenged the traditional video delivery paradigm. Given the massive amount of user-generated content shared in online social networks, users are now engaged as active participants in the social ecosystem rather than as passive receivers of media content. This revolution is being driven further by the deep penetration of 3G/4G wireless networks and smart mobile devices that are seamlessly integrated with online social networking and media-sharing s...

  3. The QoE implications of ultra-high definition video adaptation strategies

    Science.gov (United States)

    Nightingale, James; Awobuluyi, Olatunde; Wang, Qi; Alcaraz-Calero, Jose M.; Grecos, Christos

    2016-04-01

    As the capabilities of high-end consumer devices increase, streaming and playback of Ultra-High Definition (UHD) is set to become commonplace. The move to these new, higher resolution, video services is one of the main factors contributing to the predicted continuation of growth in video related traffic in the Internet. This massive increases in bandwidth requirement, even when mitigated by the use of new video compression standards such as H.265, will place an ever-increasing burden on network service providers. This will be especially true in mobile environments where users have come to expect ubiquitous access to content. Consequently, delivering UHD and Full UHD (FUHD) video content is one of the key drivers for future Fifth Generation (5G) mobile networks. One often voiced, but as yet unanswered question, is whether users of mobile devices with modest screen sizes (e.g. smartphones or smaller tablet) will actually benefit from consuming the much higher bandwidth required to watch online UHD video, in terms of an improved user experience. In this paper, we use scalable H.265 encoded video streams to conduct a subjective evaluation of the impact on a user's perception of video quality across a comprehensive range of adaptation strategies, covering each of the three adaptation domains, for UHD and FUHD video. The results of our subjective study provide insightful and useful indications of which methods of adapting UHD and FUHD streams have the least impact on user's perceived QoE. In particular, it was observed that, in over 70% of cases, users were unable to distinguish between full HD (1080p) and UHD (4K) videos when they were unaware of which version was being shown to them. Our results from this evaluation can be used to provide adaptation rule sets that will facilitate fast, QoE aware in-network adaptation of video streams in support of realtime adaptation objectives. Undoubtedly they will also promote discussion around how network service providers manage

  4. Video indexing using a high-performance and low-computation color-based opportunistic technique

    Science.gov (United States)

    Ahmed, Mohamed; Karmouch, Ahmed

    2002-02-01

    Video information, image processing, and computer vision techniques are developing rapidly because of the availability of acquisition, processing, and editing tools that use current hardware and software systems. However, problems still remain in conveying this video data to the end users. Limiting factors are the resource capabilities in distributed architectures and the features of the users' terminals. The efficient use of image processing, video indexing, and analysis techniques can provide users with solutions or alternatives. We see the video stream as a sequence of correlated images containing in its structure temporal events such as camera editing effects and presents a new algorithm for achieving video segmentation, indexing, and key framing tasks. The algorithm is based on color histograms and uses a binary penetration technique. Although much has been done in this area, most work does not adequately consider the optimization of timing performance and processing storage. This is especially the case if the techniques are designed for use in run-time distributed environments. Our main contribution is to blend high performance and storage criteria with the need to achieve effective results. The algorithm exploits the temporal heuristic characteristic of the visual information within a video stream. It takes into consideration the issues of detecting false cuts and missing true cuts due to the movement of the camera, the optical flow of large objects, or both. We provide a discussion, together with results from experiments and from the implementation of our application, to show the merits of the new algorithm as compared to the existing one.

  5. Digital video.

    Science.gov (United States)

    Johnson, Don; Johnson, Mike

    2004-04-01

    The process of digital capture, editing, and archiving video has become an important aspect of documenting arthroscopic surgery. Recording the arthroscopic findings before and after surgery is an essential part of the patient's medical record. The hardware and software has become more reasonable to purchase, but the learning curve to master the software is steep. Digital video is captured at the time of arthroscopy to a hard disk, and written to a CD at the end of the operative procedure. The process of obtaining video of open procedures is more complex. Outside video of the procedure is recorded on digital tape with a digital video camera. The camera must be plugged into a computer to capture the video on the hard disk. Adobe Premiere software is used to edit the video and render the finished video to the hard drive. This finished video is burned onto a CD. We outline the choice of computer hardware and software for the manipulation of digital video. The techniques of backup and archiving the completed projects and files also are outlined. The uses of digital video for education and the formats that can be used in PowerPoint presentations are discussed.

  6. Holistic quaternion vector convolution filter for RGB-depth video contour detection

    Science.gov (United States)

    Ti, Chunli; Xu, Guodong; Guan, Yudong; Teng, Yidan; Zhang, Ye

    2017-05-01

    A quaternion vector gradient filter is proposed for RGB-depth (RGB-D) video contour detection. First, a holistic quaternion vector system is introduced to synthetically express the color and depth information, by adding the depth to its scalar part. Then, a convolution differential operator for quaternion vector is proposed to highlight edges with both depth and chromatic variations but restrain the gradient of intensity term. In addition, the quaternion vector gradients are adaptively weighted utilizing depth confidence measure and the quadtree decomposition of the coding tree units in the video streaming. Results on the 3-D high-efficiency video coding test sequences and quantitative simulated experiments on Berkeley segmentation datasets both indicate the availability of the proposed gradient-based method on detecting the semantic contour of the RGB-D videos.

  7. DV or Not DV: That is the Question When Producing Video for the Internet

    Directory of Open Access Journals (Sweden)

    Gregory Gutenko

    2002-06-01

    Full Text Available Pervasive advertising and marketing efforts promote consumer market digital video (DV format camcorders as the ideal acquisition technology for Internet video production. A shared digital nature and simple interconnections between cameras and computers using IEEE1394/FireWire/i.Link® format digital cabling do suggest a natural affinity between DV and Internet production. However, experience with Web delivery reveals numerous obstacles associated with consumer-friendly camcorder design and feature sets that can severely compromise Internet streaming video quality. This paper describes the various features in consumer and industrial grade DV camcorder designs that lead to unnecessary image quality loss, and what must be done to avoid such loss. Conventional video production techniques that can lead to quality loss regardless of the camera technology used are also identified. A number of recommendations are offered that will help the videographer in an educational or production environment adapt to Internet limitations.

  8. A wireless video monitoring system based on 3G communication technology

    Science.gov (United States)

    Xia, Zhen-Hua; Wang, Xiao-Shuang

    2011-11-01

    With the rapid development of the electronic technology, multimedia technology and mobile communication technology, video monitoring system is going to the embedded, digital and wireless direction. In this paper, a solution of wireless video monitoring system based on WCDMA is proposed. This solution makes full use of the advantages of 3G, which have Extensive coverage network and wide bandwidth. It can capture the video streaming from the chip's video port, real-time encode the image data by the high speed DSP, and have enough bandwidth to transmit the monitoring image through WCDMA wireless network. The experiments demonstrate that the system has the advantages of high stability, good image quality, good transmission performance, and in addition, the system has been widely used, not be restricted by geographical position since it adopts wireless transmission. So, it is suitable used in sparsely populated, harsh environment scenario.

  9. Digital Video: Get with It!

    Science.gov (United States)

    Van Horn, Royal

    2001-01-01

    Several years after the first audiovisual Macintosh computer appeared, most educators are still oblivious of this technology. Almost every other economic sector (including the porn industry) makes abundant use of digital and streaming video. Desktop movie production is so easy that primary grade students can do it. Tips are provided. (MLH)

  10. Fair Play: A Study of Scientific Workforce Trainers' Experience Playing an Educational Video Game about Racial Bias

    Science.gov (United States)

    Katz, Anna; Carnes, Molly; Gutierrez, Belinda; Savoy, Julia; Samuel, Clem; Filut, Amarette; Pribbenow, Christine Maidl

    2017-01-01

    Explicit racial bias has decreased in the United States, but racial stereotypes still exist and conspire in multiple ways to perpetuate the underparticipation of Blacks in science careers. Capitalizing on the potential effectiveness of role-playing video games to promote the type of active learning required to increase awareness of and reduce…

  11. The video game experience as 'true' identification: A theory of enjoyable alterations of players' self-perception

    NARCIS (Netherlands)

    Klimmt, C.; Hefner, D.; Vorderer, P.A.

    2009-01-01

    This article introduces an explication of video game players' identification with a game character or role that is based on social-psychological models of self-perception. Contrasting with conventional ("dyadic" ) notions of media user-character relationships (e.g., parasocial interaction or

  12. Mobile video with mobile IPv6

    CERN Document Server

    Minoli, Daniel

    2012-01-01

    Increased reliance on mobile devices and streaming of video content are two of the most recent changes that have led those in the video distribution industry to be concerned about the shifting or erosion of traditional advertising revenues. Infrastructure providers also need to position themselves to take advantage of these trends. Mobile Video with Mobile IPv6provides an overview of the current mobile landscape, then delves specifically into the capabilities and operational details of IPv6. The book also addresses 3G and 4G services, the application of Mobile IPv6 to streaming and other mobil

  13. Modelling high Reynolds number wall-turbulence interactions in laboratory experiments using large-scale free-stream turbulence.

    Science.gov (United States)

    Dogan, Eda; Hearst, R Jason; Ganapathisubramani, Bharathram

    2017-03-13

    A turbulent boundary layer subjected to free-stream turbulence is investigated in order to ascertain the scale interactions that dominate the near-wall region. The results are discussed in relation to a canonical high Reynolds number turbulent boundary layer because previous studies have reported considerable similarities between these two flows. Measurements were acquired simultaneously from four hot wires mounted to a rake which was traversed through the boundary layer. Particular focus is given to two main features of both canonical high Reynolds number boundary layers and boundary layers subjected to free-stream turbulence: (i) the footprint of the large scales in the logarithmic region on the near-wall small scales, specifically the modulating interaction between these scales, and (ii) the phase difference in amplitude modulation. The potential for a turbulent boundary layer subjected to free-stream turbulence to 'simulate' high Reynolds number wall-turbulence interactions is discussed. The results of this study have encouraging implications for future investigations of the fundamental scale interactions that take place in high Reynolds number flows as it demonstrates that these can be achieved at typical laboratory scales.This article is part of the themed issue 'Toward the development of high-fidelity models of wall turbulence at large Reynolds number'. © 2017 The Author(s).

  14. Analysis of sound data streamed over the network

    Directory of Open Access Journals (Sweden)

    Jiří Fejfar

    2013-01-01

    Full Text Available In this paper we inspect a difference between original sound recording and signal captured after streaming this original recording over a network loaded with a heavy traffic. There are several kinds of failures occurring in the captured recording caused by network congestion. We try to find a method how to evaluate correctness of streamed audio. Usually there are metrics based on a human perception of a signal such as “signal is clear, without audible failures”, “signal is having some failures but it is understandable”, or “signal is inarticulate”. These approaches need to be statistically evaluated on a broad set of respondents, which is time and resource consuming. We try to propose some metrics based on signal properties allowing us to compare the original and captured recording. We use algorithm called Dynamic Time Warping (Müller, 2007 commonly used for time series comparison in this paper. Some other time series exploration approaches can be found in (Fejfar, 2011 and (Fejfar, 2012. The data was acquired in our network laboratory simulating network traffic by downloading files, streaming audio and video simultaneously. Our former experiment inspected Quality of Service (QoS and its impact on failures of received audio data stream. This experiment is focused on the comparison of sound recordings rather than network mechanism.We focus, in this paper, on a real time audio stream such as a telephone call, where it is not possible to stream audio in advance to a “pool”. Instead it is necessary to achieve as small delay as possible (between speaker voice recording and listener voice replay. We are using RTP protocol for streaming audio.

  15. Effects of Trait Hostility, Mapping Interface, and Character Identification on Aggressive Thoughts and Overall Game Experience After Playing a Violent Video Game.

    Science.gov (United States)

    Jung, Younbo; Park, Namkee; Lee, Kwan Min

    2015-12-01

    This study investigated the effects of trait-level hostility, interface types, and character identification on aggressive thoughts and overall game experience after playing a violent video game. Results showed that the mapping interface made participants with high trait-level hostility more readily accessible to aggressive contracts, yet it did not have any significant impact for participants with low trait-level hostility. Participants with low trait-level hostility reported more positive game experience in the mapping interface condition, while participants with high trait-level hostility in the same condition reported more negative game experience. Results also indicated that character identification has moderating effects on activating aggressive thoughts and mediating effects on overall game experience. Implications regarding possible ways of reducing potentially negative outcomes from violent games are discussed.

  16. Video time encoding machines.

    Science.gov (United States)

    Lazar, Aurel A; Pnevmatikakis, Eftychios A

    2011-03-01

    We investigate architectures for time encoding and time decoding of visual stimuli such as natural and synthetic video streams (movies, animation). The architecture for time encoding is akin to models of the early visual system. It consists of a bank of filters in cascade with single-input multi-output neural circuits. Neuron firing is based on either a threshold-and-fire or an integrate-and-fire spiking mechanism with feedback. We show that analog information is represented by the neural circuits as projections on a set of band-limited functions determined by the spike sequence. Under Nyquist-type and frame conditions, the encoded signal can be recovered from these projections with arbitrary precision. For the video time encoding machine architecture, we demonstrate that band-limited video streams of finite energy can be faithfully recovered from the spike trains and provide a stable algorithm for perfect recovery. The key condition for recovery calls for the number of neurons in the population to be above a threshold value.

  17. Applications of Scalable Multipoint Video and Audio Using the Public Internet

    Directory of Open Access Journals (Sweden)

    Robert D. Gaglianello

    2000-01-01

    Full Text Available This paper describes a scalable multipoint video system, designed for efficient generation and display of high quality, multiple resolution, multiple compressed video streams over IP-based networks. We present our experiences using the system over the public Internet for several “real-world” applications, including distance learning, virtual theater, and virtual collaboration. The trials were a combined effort of Bell Laboratories and the Gertrude Stein Repertory Theatre (TGSRT. We also present current advances in the conferencing system since the trials, new areas for application and future applications.

  18. Stream systems.

    Science.gov (United States)

    Jack E. Williams; Gordon H. Reeves

    2006-01-01

    Restored, high-quality streams provide innumerable benefits to society. In the Pacific Northwest, high-quality stream habitat often is associated with an abundance of salmonid fishes such as chinook salmon (Oncorhynchus tshawytscha), coho salmon (O. kisutch), and steelhead (O. mykiss). Many other native...

  19. Social Properties of Mobile Video

    Science.gov (United States)

    Mitchell, April Slayden; O'Hara, Kenton; Vorbau, Alex

    Mobile video is now an everyday possibility with a wide array of commercially available devices, services, and content. These new technologies have created dramatic shifts in the way video-based media can be produced, consumed, and delivered by people beyond the familiar behaviors associated with fixed TV and video technologies. Such technology revolutions change the way users behave and change their expectations in regards to their mobile video experiences. Building upon earlier studies of mobile video, this paper reports on a study using diary techniques and ethnographic interviews to better understand how people are using commercially available mobile video technologies in their everyday lives. Drawing on reported episodes of mobile video behavior, the study identifies the social motivations and values underpinning these behaviors that help characterize mobile video consumption beyond the simplistic notion of viewing video only to kill time. This paper also discusses the significance of user-generated content and the usage of video in social communities through the description of two mobile video technology services that allow users to create and share content. Implications for adoption and design of mobile video technologies and services are discussed as well.

  20. Performance Analysis of Video Transmission Using Sequential Distortion Minimization Method for Digital Video Broadcasting Terrestrial

    Directory of Open Access Journals (Sweden)

    Novita Astin

    2016-12-01

    Full Text Available This paper presents about the transmission of Digital Video Broadcasting system with streaming video resolution 640x480 on different IQ rate and modulation. In the video transmission, distortion often occurs, so the received video has bad quality. Key frames selection algorithm is flexibel on a change of video, but on these methods, the temporal information of a video sequence is omitted. To minimize distortion between the original video and received video, we aimed at adding methodology using sequential distortion minimization algorithm. Its aim was to create a new video, better than original video without significant loss of content between the original video and received video, fixed sequentially. The reliability of video transmission was observed based on a constellation diagram, with the best result on IQ rate 2 Mhz and modulation 8 QAM. The best video transmission was also investigated using SEDIM (Sequential Distortion Minimization Method and without SEDIM. The experimental result showed that the PSNR (Peak Signal to Noise Ratio average of video transmission using SEDIM was an increase from 19,855 dB to 48,386 dB and SSIM (Structural Similarity average increase 10,49%. The experimental results and comparison of proposed method obtained a good performance. USRP board was used as RF front-end on 2,2 GHz.