100,810 research outputs found

    Structuring lecture videos for distance learning applications. ISMSE

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    This paper presents an automatic and novel approach in structuring and indexing lecture videos for distance learning applications. By structuring video content, we can support both topic indexing and semantic querying of multimedia documents. In this paper, our aim is to link the discussion topics extracted from the electronic slides with their associated video and audio segments. Two major techniques in our proposed approach include video text analysis and speech recognition. Initially, a video is partitioned into shots based on slide transitions. For each shot, the embedded video texts are detected, reconstructed and segmented as high-resolution foreground texts for commercial OCR recognition. The recognized texts can then be matched with their associated slides for video indexing. Meanwhile, both phrases (title) and keywords (content) are also extracted from the electronic slides to spot the speech signals. The spotted phrases and keywords are further utilized as queries to retrieve the most similar slide for speech indexing. 1

    Interactive searching and browsing of video archives: using text and using image matching

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    Over the last number of decades much research work has been done in the general area of video and audio analysis. Initially the applications driving this included capturing video in digital form and then being able to store, transmit and render it, which involved a large effort to develop compression and encoding standards. The technology needed to do all this is now easily available and cheap, with applications of digital video processing now commonplace, ranging from CCTV (Closed Circuit TV) for security, to home capture of broadcast TV on home DVRs for personal viewing. One consequence of the development in technology for creating, storing and distributing digital video is that there has been a huge increase in the volume of digital video, and this in turn has created a need for techniques to allow effective management of this video, and by that we mean content management. In the BBC, for example, the archives department receives approximately 500,000 queries per year and has over 350,000 hours of content in its library. Having huge archives of video information is hardly any benefit if we have no effective means of being able to locate video clips which are of relevance to whatever our information needs may be. In this chapter we report our work on developing two specific retrieval and browsing tools for digital video information. Both of these are based on an analysis of the captured video for the purpose of automatically structuring into shots or higher level semantic units like TV news stories. Some also include analysis of the video for the automatic detection of features such as the presence or absence of faces. Both include some elements of searching, where a user specifies a query or information need, and browsing, where a user is allowed to browse through sets of retrieved video shots. We support the presentation of these tools with illustrations of actual video retrieval systems developed and working on hundreds of hours of video content

    Modal density in structuring segments containing organizational metadiscourse versus content sequences

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    Organizational metadiscourse in lectures helps to facilitate comprehension and is frequently found in structuring segments placed in between content sequences. In contrast, content sequences are those parts of the discourse which carry the main ideas to be developed in the lecture. Although there is ample literature that explores the use of metadiscourse in lectures, to the best of our knowledge, no previous research has compared both parts of the monological classroom discourse with regard to the semiotic resources used by lecturers. Thus, this paper aims to compare and contrast structuring segments and content sequences with a focus on the use of multimodal resources. In order to do so, six structuring segments with a high number of organizational metadiscourse instances and six content sequences from six different lectures have been selected. These lectures are face-to-face recorded sessions that belong to Humanities courses at Yale University OpenCourseWare. Through the observation of short clips and multimodal transcriptions using the software Multimodal Analysis Video, I present quantitative and qualitative data that provides evidence that organizational metadiscourse is most often co-expressed with non-verbal resources in structuring segments, which contributes to emphasizing the connections across the contents, and to engaging the audience. In other words, structuring segments appear to be more modally dense than content sequences

    1D-mosaics grouping using lattice vector quantization for a video browsing application

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    International audience1D-mosaics have been introduced as a tool for structuring and navigation in video content. These objects can be con- sidered as the spatio-temporal signatures of the video shots. Our work aims at grouping automatically the video shots into scenes using these signatures. The original method is based on the tree-structured lattice vector quantization of the 1D-mosaics. Because of the hierarchical structure of the code-books, they can be compared progressively, and lattice use is time efïŹcient. Indexing retrieval results are given for two video sequences, and different mosaics are successively compared to each other in order to assess the presented scheme's effectiveness

    Facilitating collaborative knowledge construction in computer-mediated learning with structuring tools

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    Collaborative knowledge construction in computer-mediated learning environments puts forward difficulties regarding what tasks learners work on and how learners interact with each other. For instance, learners who collaboratively construct knowledge in computer-mediated learning environments sometimes do not participate actively or engage in off-task talk. Computer-mediated learning environments can be endorsed with socio-cognitive structuring tools that structure the contents to be learned and suggest specific interactions for collaborative learners. In this article, two studies will be reported that applied content- and interaction-oriented structuring tools in computer-mediated learning environments based on electronic bulletin boards and videoconferencing technologies. In each study the factors "content-oriented structuring tool" and "interaction-oriented structuring tool" have been independently varied in a 2X2-factorial design. Results show that interaction-oriented structuring tools substantially foster the processes of collaborative knowledge construction as well as learning outcomes. The content-oriented structuring tools facilitate the processes of collaborative knowledge construction, but have no or negative effects on learning outcome. The findings will be discussed against the background of recent literatGemeinsame Wissenskonstruktion in computervermittelten Lernumgebungen birgt Schwierigkeiten in Bezug darauf, welche Aufgaben Lernende bearbeiten und wie sie dabei miteinander interagieren. Lernende, die gemeinsam Wissen in computervermittelten Lernumgebungen konstruieren, nehmen z. B. manchmal nicht aktiv an der Bearbeitung von Lernaufgaben teil oder beschĂ€ftigen sich mit inhaltsfremden Themen. Computervermittelte Lernumgebungen können mit Hilfe sozio-kognitiver Strukturierungswerkzeuge unterstĂŒtzt werden, die die Lerninhalte vorstrukturieren und den Lernenden spezifische Interaktionen nahe legen. In diesem Beitrag werden zwei Studien berichtet, die inhalts- und interaktionsbezogene Strukturierungswerkzeuge in computervermittelten Lernumgebungen, die auf web-basierten Diskussionsforen und Videokonferenz-Technologien beruhen, zum Einsatz gebracht und analysiert haben. In jeder der Studien wurden die Faktoren "inhaltsbezogenes Strukturierungswerkzeug" und "interaktionsbezogenes Strukturierungswerkzeug" unabhĂ€ngig voneinander in einem 2X2-Design variiert. Die Ergebnisse zeigen, dass interaktionsbezogene Strukturierungswerkzeuge die Prozesse sowie die Ergebnisse gemeinsamer Wissenskonstruktion substanziell fördern können. Die inhaltsbezogenen Strukturierungswerkzeuge unterstĂŒtzen die Prozesse gemeinsamer Wissenskonstruktion, zeitigen aber keine oder negative Effekte auf die Lernergebnisse. Die Befunde werden vor dem Hintergrund aktueller theoretischer AnsĂ€tze diskut

    SMIL State: an architecture and implementation for adaptive time-based web applications

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    In this paper we examine adaptive time-based web applications (or presentations). These are interactive presentations where time dictates which parts of the application are presented (providing the major structuring paradigm), and that require interactivity and other dynamic adaptation. We investigate the current technologies available to create such presentations and their shortcomings, and suggest a mechanism for addressing these shortcomings. This mechanism, SMIL State, can be used to add user-defined state to declarative time-based languages such as SMIL or SVG animation, thereby enabling the author to create control flows that are difficult to realize within the temporal containment model of the host languages. In addition, SMIL State can be used as a bridging mechanism between languages, enabling easy integration of external components into the web application. Finally, SMIL State enables richer expressions for content control. This paper defines SMIL State in terms of an introductory example, followed by a detailed specification of the State model. Next, the implementation of this model is discussed. We conclude with a set of potential use cases, including dynamic content adaptation and delayed insertion of custom content such as advertisements. © 2009 Springer Science+Business Media, LLC

    Fostering collaborative knowledge construction in desktop videoconferencing. Effects of content schemes and cooperation scripts in peer teaching settings

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    Video-conferencing is expected to become increasingly important for tele-learning environments. In contrast to asynchronous, text-based computer-mediated communication, video-conferencing facilitates cooperation tasks that require highly frequent and continuous coordination. Typical kinds of such cooperation tasks are found in peer teaching settings. Despite the growing application of video-conferencing, only little is known about possibilities of enhancing collaboration in video-conferencing settings. This study investigates the effects of different types of support for cooperation on the learning outcomes of peer dyads in a video-conferencing scenario. The main research question is how cooperation scripts and content schemes enhance the students' cognitive activities and foster the outcomes of cooperative learning. Two factors were varied experimentally: The content scheme (with/without) and the cooperation script (with/without). 86 university students of educational psychology participated in the study. Each student of a dyad received a text dealing with a psychological theory in the field of the nature-nurture-debate. The students' tasks were (1) to teach their partners the relevant contents of their text and (2) to reflect ideas that went beyond the scope of the text. Results indicate that in particular the cooperation script en-hances learning outcomes of collaborative knowledge constructionVideokonferenzen werden fĂŒr die Gestaltung netzbasierter Lernumgebungen zunehmend interessant. Im Gegensatz zu asynchroner, textbasierter computervermittelter Kommunikation, ermöglichen Videokonferenzen Kooperationsaufgaben, die einen ho-hen Grad an Koordination erfordern. Typische Beispiele hierfĂŒr sind Peer-Tutoring- bzw. Peer-Teaching Arrangements. Trotz der zunehmenden Bedeutung von Videokonferenztechnologien ist bisher nur relativ wenig hinsichtlich der Förderung kooperativen Lernens mit diesem Medium bekannt. Diese Studie untersucht die Effekte verschiedener Fördermaßnahmen auf Ergebnisse der gemeinsamen Wissenskonstruktion beim dyadischen Lernen in einer Videokonferenz. Untersucht wird hierbei der Einfluss eines Kooperationsskripts und eines inhaltlichen Strukturschemas. In einem zweifaktoriellen Design wurden die beiden Einflussfaktoren Kooperationsskript (mit/ohne) und inhaltliches Strukturschema (mit/ohne) experimentell variiert. 86 Studierende der PĂ€dagogik nahmen an der Studie teil. Jeder Teilnehmer erhielt einen Text ĂŒber eine psychologische Theorie zum Thema der Anlage-Umwelt Debatte. Die Aufgabe der Studierenden bestand darin, (1) dem Lernpartner die relevanten Inhalte des eigenen Theorietextes zu vermitteln und (2) Ideen, die ĂŒber die Inhalte des Textes hinausgingen zu elaborieren. Die hier vorgestellten Ergebnisse zeigen, dass insbesondere das Kooperationsskript den Lernerfolg steigert. Weitere Prozessanalysen sind notwendi

    A reconfigurable real-time morphological system for augmented vision

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    There is a significant number of visually impaired individuals who suffer sensitivity loss to high spatial frequencies, for whom current optical devices are limited in degree of visual aid and practical application. Digital image and video processing offers a variety of effective visual enhancement methods that can be utilised to obtain a practical augmented vision head-mounted display device. The high spatial frequencies of an image can be extracted by edge detection techniques and overlaid on top of the original image to improve visual perception among the visually impaired. Augmented visual aid devices require highly user-customisable algorithm designs for subjective configuration per task, where current digital image processing visual aids offer very little user-configurable options. This paper presents a highly user-reconfigurable morphological edge enhancement system on field-programmable gate array, where the morphological, internal and external edge gradients can be selected from the presented architecture with specified edge thickness and magnitude. In addition, the morphology architecture supports reconfigurable shape structuring elements and configurable morphological operations. The proposed morphology-based visual enhancement system introduces a high degree of user flexibility in addition to meeting real-time constraints capable of obtaining 93 fps for high-definition image resolution
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