多媒体直播课堂软件系统的设计

针对目前多媒体教室的资源不能被远程教育的学生有效利用的现象,结合音频、视频和屏幕图像压缩算法的压缩比率不断提高的特点,提出了一种多媒体直播课堂软件系统,给出了其系统框架,并详细介绍了该系统的Web服务器、编码服务器、直播服务器、流媒体代理服务器和客户端的设计.该系统与类似系统相比,不受电子讲稿种类多样性的限制,可适应更多的多媒体压缩算法,在传输效率上也有一定的优势.     

Telelearning in the virtual lecture theatre

The concept of a virtual lecture theatre has been realised at the Faculty of Economics, Business Administration and Social Sciences in Nuremberg since 1995. Interdisciplinary courses are being held for local students at one faculty and are interactively broadcast for students joining in from remote locations. Various demands concerning the teleteaching environment have to be met in order to enable remote students to attend lectures virtually and interact synchronously by sending contributions via conferencing tools to the central lecture theatre. In addition, recorded lectures are digitised and stored on a multimedia server to provide asynchronous access for all students, constituting a “lecture on demand” system. Furthermore, remote students are able to co-operate virtually with other students, i.e. join exercise groups by means of video and audio communication, share screens and applications, exchange documents and software, etc. To fulfil the corresponding multimedia communication needs, a broadband ATM (asynchronous transfer mode) network connects the lecture theatre in Nuremberg with remote lecture theatres, remote conferencing rooms and separate workplaces at the university or at home.     

Rapid prototyping for a virtual medical campus interface

The Virtual Medical Campus Graz uses e-learning to make the human medicine curriculum digitally accessible to a target population of 4500 students and teachers. This project occurred parallel to the development of a new curriculum and thus involved all medical teachers and students. The VMC system architecture includes a multimedia repository for reusable learning objects; middleware containing the VMC logic that arranges learning objects into lectures, themes, and modules; and user interface. To ensure the interface suited the target population, we used the user-centered design method.     

基于SMIL的多媒体网络教学系统的设计与实现

简述了同步多媒体集成语言SMIL，介绍了基于SMIL设计的一个多媒体网络教学系统的体系结构、功能和实现技术。使用所开发的系统，教师能轻松地制作出多媒体课件，实现课程的网上直播；学生能实时同步地收看教师授课的音频、视频和教师机屏幕图像信息，并可通过文字交流窗口进行实时文字交流；此外，学生在课后能随时自主点播课件。所开发的系统经在授课中试用，取得了良好效果。     

Live interdisciplinary teaching via the internet

The independence of teachers and students is one of the main advantages of teleteaching. Specialties considered unsuitable for combined lessons are manageable using the internet. This study outlines simultaneous communication with students and lecturers over long distances between the anatomical dissection laboratory, the operating theatre, and the lecture hall. In several three-directional on-line lectures, different equipment was used. Students could also participate using personal computers from other locations. During the presentations, the participants have the opportunity to discuss problems with any lecturer. It was possible to demonstrate sufficient transmission capability for real-time application with the use of the new internet technology. No important qualitative differences can be reported between: hardware and software based solutions; or commercial and free offers. Although it is often difficult to reconcile the timetable of surgeries and lectures, multimedia on-line teaching via the internet provides new potential for interdisciplinary medical education.     

基于JMF的音视频实时交互及存储的具体实现

针对目前多媒体远程教学及实时监控系统大部分是信息单向传输，缺乏用户间的多媒体信息实时交互功能及多媒体数据存储海量的弊端，文章提供了一种用JMF的数据克隆、数据轨道控制、流媒体的存储及传输等技术来实现网络音、视频数据双向传输及由用户选择和控制将音视频数据以MOV文件格式存储到本地硬盘的方案，并介绍了实现方法。系统软、硬件成本低，且数据量小，易于网络传输和存储。     

Using learning styles and viewing styles in streaming video

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.     

Cross-Campus Collaboration to Produce Camtasia-Enhanced Lessons to Improve Distance Learning

This pilot study examines the use of Camtasia-enhanced lessons to supplement distance education provided to medical laboratory science students. More programs of study are available as distance learning opportunities, creating challenges to find better ways to present material. Librarians provided technical expertise necessary to produce a Camtasia video. This helped instructors prepare engaging lectures for phlebotomy to supplement the PowerPoint presentations and self-directed lessons provided in previous courses. Medical laboratory science faculty collaborated with library staff to produce videos that demonstrate proper phlebotomy technique using training personnel and faculty, whom the students eventually interact with in the clinical environment.     

Content-based management of video in a multimedia authoring environment

This paper describes architecture and implementation of a multimedia authoring environment which features content-based management of video.The goal of our work is to provide multimedia application developers with a useful video database, where they gather video materials from various sources, store them in a organized format, and use them in multimedia applications. The principal design concepts are that (1) it should have a flexible means to store video materials in a organized format so that video clips can be retrieved easily, and that (2) it should have a view to each application so that various applications can share the video materials.To meet these requirements we designed a multimedia authoring system based on a video object model. The video object model features (1) a method to attach annotations not only to scenes but also to things shot in the video, and (2) a method to define video clips independently from physical video data.Our experiences in using the system to develop a multimedia CAI application are also described to show the advantages of our system.     

Real-time imaging-based assessment model for improving teaching performance and student experience in e-learning

Multimedia is an essential and integral part of electronic learning (e-learning). In this study, teaching performance and student learning experience are measured using real-time multimedia processing tools and techniques for the e-learning paradigm. Visual attention and visual engagement analysis are performed using two developed algorithms. Video lectures are recorded and delivered to students in e-learning pedagogical setup, which are examined for the visual attention and visual engagement of the student and teacher, respectively. Proposed methodology integrates the assessment on both student and teacher ends. Multimedia processing of video lectures for teaching performance produces scoring dataset. The same methodology on student end for visual attention is used to investigate student experience. These types of datasets then reduced to time-based datasets from the image-based dataset. Correlation and association of both datasets provide the opportunity to relate both student experience and teaching performance as well as to move forward to create content that is more useful. Computational performance of the developed algorithms is compared using different video lectures with their processed frames per second, which is analyzed as per their corresponding bins. Mean, max, and median of the processed frames of all the processed videos are also compared.     

Live Screen Capture软件在医学视频课件制作中的应用综述

Pinnacle studio 17下附带子程序Live Screen Capture的屏幕捕捉功能即可完成多媒体视频课件的制作,快速完成多媒体视频课件的制作方法以便教学应用,此软件操作方法简单易上手,能够快速完成多媒体视频课件的制作,是比较实用的医学多媒体视频课件制作方法.     

Effects of different video lecture types on sustained attention,emotion, cognitive load,and learning performance

Although online courseware often includes multimedia materials, exactly how different video lecture types impact student performance has seldom been studied. Therefore, this study explores how three commonly used video lectures styles affect the sustained attention, emotion, cognitive load, and learning performance of verbalizers and visualizers in an autonomous online learning scenario by using a two-factor experimental design, brainwave detection, emotion-sensing equipment, cognitive load scale, and learning performance test sheet. Analysis results indicate that, while the three video lecture types enhance learning performance, learning performance with lecture capture and picture-in-picture types is superior to that associated with the voice-over type. Verbalizers and visualizers achieve the same learning performance with the three video types. Additionally, sustained attention induced by the voice-over type is markedly higher than that with the picture-in-picture type. Sustained attention of verbalizers is also significantly higher than that of visualizers when learning with the three video lectures. Moreover, the positive and negative emotions induced by the three video lectures do not appear to significantly differ from each other. Also, cognitive load related to the voice-over type is significantly higher than that with by the lecture capture and picture-in-picture types. Furthermore, the cognitive load for visualizers markedly exceeds that of verbalizers who are presented with the voice-over type. Results of this study significantly contribute to efforts to design of video lectures and also provide a valuable reference when selecting video lecture types for online learning.     

Migrating legacy video lectures to multimedia learning objects

Video lectures are an old distance learning approach that offers only basic interaction and retrieval features to the user. Thus, to follow the new learning paradigms, we need to re‐engineer the e‐learning processes while preserving the investments made in the past. In this paper we present an approach for migrating video lectures to multimedia learning objects. Two essential problems are tackled: the detection of slide transitions and the generation of the learning objects. To this aim, the video of the lecture is scanned to detect the slide changes, while the learning object metadata and the slide pictures are extracted from the presentation document. A tool named VLMigrator (video lecture migrator) has been developed to support the migration of video lectures and the restructuring of their contents in terms of learning objects. Both the migration strategy and the tool have been experimented in a case study. Copyright © 2008 John Wiley & Sons, Ltd.     

一种基于WWW的在线答疑系统

基于WWW的在线课程答疑系统,采用B/S模式,是目前最为流行的一种方式,具有高效、快捷、安全等特性。师生可以通过基于H.323的视频答疑系统进行多种方式的互动和交流。阐述了H.323多媒体通信标准的优越性,介绍了H.323的标准体系结构,对H.323终端结构进行了分析研究,分析了H.323视频会议的逻辑系统结构。     

Modeling, design, development and evaluation of a hypervideo presentation for digital systems teaching and learning

Hypervideos are multimedia files, which differ from traditional video files in that they can be navigated by using links that are embedded in them. Students can therefore easily access content that explains and clarifies certain points of the lectures that are difficult to understand, while at the same time not interrupting the flow of the original video presentation. In this paper we report on the design, development and evaluation of a hypermedia e-Learning tool for university students. First, the structure of the hypervideo model is presented; once the structure is known, the process of creating hypervideo content is described in detail, as are the various ways in which content can be linked together. Finally, an evaluation is presented, which has been carried out in the context of an engineering class by use of an interactive experiment, involving N = 88 students from a digital systems course. In this study the students were randomly assigned to two groups; one group participated in the course as usual, whilst the second group participated in the same course while also combining the conventional learning with the hypervideo content developed for the course. The students’ learning results showed that the students who had access to the hypervideo content performed significantly better than the comparison group.     

Multi-media instructional approach to teaching linear programming

This paper describes different strategies employed in converting a lecture-oriented mathematical programming course to a Personalized Self-Paced Instructional (PSI) format. This is an elective course for students in science, engineering and management. A multi media instructional approach is used in the PSI system which combines traditional lectures, self-paced and individualized learning assisted by interactive computer programs and video taped instructional materials. This unique PSI system for mathematical programming provides maximum learning opportunity and flexibility to students. The author's experiences with the PSI system and the students' evaluation of the self-paced system are also discussed.     

基于网络的微视频教学系统的研究

目前,我国的多媒体网络视频教学平台的应用和开发还处于探索中,特别是微视频教学平台刚处于起步阶段,研究和开发一套各所大学可以晋及的多媒体微视频教学系统具有很大的实用价值,通过这一微视频教学系统,可以实时录制和发布任何一门课、任何老师的任何一个时间段的讲课微视频,通过资源整合,建立一个大型的开放的众多学科、专业齐全的课程分章分节的教学微视频资源库,并通过网络平台进行微视频上传和发布,让学生可以随时浏览观看教学微视频,供所有网络学习者在随时随地进行学习,建立一个真正意义上的包括海量微视频的在线学习的网络视频学习平台。     

Structuring low-quality videotaped lectures for cross-reference browsing by video text analysis

This paper presents an unified approach in analyzing and structuring the content of videotaped lectures for distance learning applications. By structuring lecture videos, we can support topic indexing and semantic querying of multimedia documents captured in the traditional classrooms. Our goal in this paper is to automatically construct the cross references of lecture videos and textual documents so as to facilitate the synchronized browsing and presentation of multimedia information. The major issues involved in our approach are topical event detection, video text analysis and the matching of slide shots and external documents. In topical event detection, a novel transition detector is proposed to rapidly locate the slide shot boundaries by computing the changes of text and background regions in videos. For each detected topical event, multiple keyframes are extracted for video text detection, super-resolution reconstruction, binarization and recognition. A new approach for the reconstruction of high-resolution textboxes based on linear interpolation and multi-frame integration is also proposed for the effective binarization and recognition. The recognized characters are utilized to match the video slide shots and external documents based on our proposed title and content similarity measures.     

Extracting semantics from audio-visual content: the final frontier in multimedia retrieval

Multimedia understanding is a fast emerging interdisciplinary research area. There is tremendous potential for effective use of multimedia content through intelligent analysis. Diverse application areas are increasingly relying on multimedia understanding systems. Advances in multimedia understanding are related directly to advances in signal processing, computer vision, pattern recognition, multimedia databases, and smart sensors. We review the state-of-the-art techniques in multimedia retrieval. In particular, we discuss how multimedia retrieval can be viewed as a pattern recognition problem. We discuss how reliance on powerful pattern recognition and machine learning techniques is increasing in the field of multimedia retrieval. We review the state-of-the-art multimedia understanding systems with particular emphasis on a system for semantic video indexing centered around multijects and multinets. We discuss how semantic retrieval is centered around concepts and context and the various mechanisms for modeling concepts and context.     

Video transcoding: an overview of various techniques and research issues

One of the fundamental challenges in deploying multimedia systems, such as telemedicine, education, space endeavors, marketing, crisis management, transportation, and military, is to deliver smooth and uninterruptible flow of audio-visual information, anytime and anywhere. A multimedia system may consist of various devices (PCs, laptops, PDAs, smart phones, etc.) interconnected via heterogeneous wireline and wireless networks. In such systems, multimedia content originally authored and compressed with a certain format may need bit rate adjustment and format conversion in order to allow access by receiving devices with diverse capabilities (display, memory, processing, decoder). Thus, a transcoding mechanism is required to make the content adaptive to the capabilities of diverse networks and client devices. A video transcoder can perform several additional functions. For example, if the bandwidth required for a particular video is fluctuating due to congestion or other causes, a transcoder can provide fine and dynamic adjustments in the bit rate of the video bitstream in the compressed domain without imposing additional functional requirements in the decoder. In addition, a video transcoder can change the coding parameters of the compressed video, adjust spatial and temporal resolution, and modify the video content and/or the coding standard used. This paper provides an overview of several video transcoding techniques and some of the related research issues. We introduce some of the basic concepts of video transcoding, and then review and contrast various approaches while highlighting critical research issues. We propose solutions to some of these research issues, and identify possible research directions.