Disk placement for arbitrary-rate playback in an interactive video server

Multimedia data, especially continuous media including video and audio objects, represent a rich and natural stimulus for humans, but require large amount of storage capacity and real-time processing. In this paper, we describe how to organize video data efficiently on multiple disks in order to support arbitrary-rate playback requested by different users independently. Our approach is to segment and decluster video objects and to place the segments in multiple disks using a restricted round-robin scheme, called prime round-robin (PRR). Its placement scheme provides uniform load balance of disks for arbitrary retrieval rate as well as normal playback, since it eliminates hot spots. Moreover, it does not require any additional disk bandwidth to support VCR-like operations such as fast-forward and rewind. We have studied the various effects of placement and retrieval schemes in a storage server by simulation. The results show that PRR offers even disk accesses, and the failure in reading segment by deadline occurs only at the beginning of new operations. In addition, the number of users admitted is not decreased, regardless of arbitrary-rate playback requests.     

Towards an easy to use authoring tool for interactive non-linear video

With growing bandwidths in the Internet and seemingly unlimited storage capacities on web servers, media became more and more important in the daily use of the World Wide Web. While about ten years ago only text and images with small file sizes (and as a result small resolutions) could be used, it is possible to watch high quality multimedia presentations nowadays. But those rarely exist because of tedious to learn authoring tools. A specialization to one main medium, in our case video, allows creating efficient authoring tools using well known paradigms. This work introduces an authoring tool called SIVA Producer. An iterative process for improving the usability of the authoring tool is described. Furthermore, a distinction of the terms “interactive video”, “annotated video”, “non-linear video” and “hypervideo” is given.     

Personal orchestra: a real-time audio/video system for interactive conducting

We present the first multimedia system to conduct a realistic electronic orchestra. Users can control tempo, dynamics, and instrument emphasis of the orchestra through natural conducting gestures with an infrared baton. Using gesture recognition and tempo adjustment algorithms, the system plays back an audio and video recording of an actual orchestra that follows the users conducting in real time. A major achievement of this system is its ability to vary playback speed in real time while avoiding audio artifacts such as pitch changes. The system has been deployed as an exhibit and has become a major attraction of a large Vienna-based music exhibition center.An erratum to this article can be found at     

Efficient support for interactive operations in multi-resolution video servers

In this paper, we present a placement algorithm that interleaves multi-resolution video streams on a disk array and enables a video server to efficiently support playback of these streams at different resolution levels. We then combine this placement algorithm with a scalable compression technique to efficiently support interactive scan operations (i.e., fast-forward and rewind). We present an analytical model for evaluating the impact of the scan operations on the performance of disk-arr ay-based servers. Our experiments demonstrate that: (1) employing our placement algorithm substantially reduces seek and rotational latency overhead during playback, and (2) exploiting the characteristics of video streams and human perceptual tolerances enables a server to support interactive scan operations without any additional overhead.     

VideoMap: An interactive and scalable visualization for exploring video content

Computational Visual Media - Large-scale dynamic relational data visualization has attracted considerable research attention recently. We introduce dynamic data visualization into the multimedia...     

Instructional video in e-learning: Assessing the impact of interactive video on learning effectiveness

Interactive video in an e-learning system allows proactive and random access to video content. Our empirical study examined the influence of interactive video on learning outcome and learner satisfaction in e-learning environments. Four different settings were studied: three were e-learning environments—with interactive video, with non-interactive video, and without video. The fourth was the traditional classroom environment. Results of the experiment showed that the value of video for learning effectiveness was contingent upon the provision of interactivity. Students in the e-learning environment that provided interactive video achieved significantly better learning performance and a higher level of learner satisfaction than those in other settings. However, students who used the e-learning environment that provided non-interactive video did not improve either. The findings suggest that it may be important to integrate interactive instructional video into e-learning systems.     

Search for a moving object in a problem with many searchers

Translated from Kibernetika i Sistemnyi Analiz, No. 5, pp. 109–114, September–October, 1995.     

Efficient support for interactive browsing operations in clusteredCBR video servers

Providing efficient support for interactive browsing operations such as fast-forward (ff) and fast-backward (fb) is essential in video-on-demand and other multimedia server systems. In this paper, we propose two basic approaches to scheduling interactive browsing operations: 1) the prefetching approach and 2) the grouping approach. Block-skipping and frame-skipping algorithms are presented for constant bit rate (CBR) data blocks. These algorithms can precisely schedule video streams for both normal play and interactive browsing operations     

An analytical model for interval caching in interactive video servers

Design of servers to meet the quality of service (QoS) requirements of interactive video-on-demand (VOD) systems is challenging. Recognizing the increasing use of these systems in a wide range of applications, as well as the stringent service demands expected from them, several design alternatives have been proposed to improve server throughput. A buffer management technique, called interval caching, is one such solution which exploits the temporal locality of requests to the same movie and tries to serve requests from the cache, thereby enhancing system throughput.In this paper, we present a comprehensive mathematical model for analyzing the performance of interactive video servers that use interval caching. The model takes into account the representative workload parameters of interactive servers employing interval caching and calculates the expected number of cached streams as an indication of the improvement in server capacity due to interval caching. Especially, user interactions, which sensitively affect the performance of interval caching, are realistically reflected in our model for an accurate analysis. A statistical admission control technique has also been developed based on this model. Using this model as a design tool, we apply the model to measure the impact of different VCR operations on client requests and rejection probability, as well as the effect of cache size.     

Towards hierarchical context: unfolding visual community potential for interactive video retrieval

Community structure as an interesting property of network has attracted wide attention from many research fields. In this paper, we exploit the visual community structure in visual-temporal correlation network and utilize it to improve interactive video retrieval. Firstly, we propose a hierarchical community-based feedback algorithm. By re-ranking the video shots through diffusion processes respectively on the inter-community and intra-community level, the feedback algorithm can make full use of the limited user feedback. Furthermore, since it avoids entire graph computation, the feedback algorithm can make quick responses to user feedback, which is particularly important for the large video collections. Secondly, we propose a community-based visualization interface called VideoMap. By organizing the video shots following the community structure, the VideoMap presents a comprehensive and informative view of the whole dataset to facilitate users’ access. Moreover, the VideoMap can help users to quickly locate the potential relevant regions and make active annotation according to the distribution of labeled samples on the VideoMap. Experiments on TRECVID 2009 search dataset demonstrate the efficiency of the feedback algorithm and the effectiveness of the visualization interface.     

Design considerations for the development of interactive video in nurse education

Nurse education is one area which combines both a high level of technical skill and knowledge within a working environment in which inter-personal skills are vital. Thus it was considered appropriate to carry out a feasibility study on the use of interactive video in nurse education. The subject chosen was that of intravenous care because of the increasing evidence demonstrating both the hazards to the patient of poor practice and the poor knowledge base of practitioners, medical and nursing, in a climate of increasing technology and pharmacology associated with the intravenous route. The complexity of such a subject required a richness in the educational strategies employed in interacting with the video and the knowledge base within the computer. Furthermore, the need for independant validation of the content was essential in a development area that aimed to provide a high, if not national standard of care for a nursing procedure. Developments in this area highlighted the need for a team approach to the design and development process involving subject experts and designers led by an educational systems analyst. This paper will outline the design methodology employed in a feasibility study for an interactive video program for the training and assessment of nurses in the care required by a patient receiving intravenous therapy and medication.     

基于协同关联粒子滤波算法的交互多视频目标跟踪

首先介绍了带马尔科夫跳变非线性系统(JMNSs)的状态估计问题,然后总结了JMNSs最优状态估计的难点和具有交互作用的多目标跟踪问题.在总结分析各类不同算法的基础上,提出了一种协同关联粒子滤波算法来解决目标数目在变化的交互多目标跟踪问题,改进后的算法不需要观测与目标状态关联和目标数量已知的假设.最后,通过仿真实验验证了改进后的算法在跟踪效果上优于现有算法,并能成功估计目标的数量.     

The system design for GALATEA,an interactive real-time computer graphics system for movie and video analysis

The extraction of information from movie film and videotape has always been a very tedious process. Yet the usefulness of these media in biomedical research, behavioral science, industrial testing, etc., is apparent. We are developing a system, GALATEA, for the rapid extraction of data from film or video using interactive graphics. The key aspects of GALATEA are: the user indicates what features are of interest using an x, y digitizing pen. These pen positions are the only data the system sees, so that full digital image encoding is avoided. The user can trace the features while the film runs (frame-by-frame analysis is not necessary). The user has constant feedback in the form of an animated, computer-generated movie (Kinegram), overlaid on the original film image and running synchronously with it. It is this kinetic feedback of the data entered that makes the system efficient. Structured programming, real-time programming techniques, data structures for time-dependent pictures and dynamical graphics ‘tools’ are covered. A detailed discussion is given of Slippage or soft degradation in real-time systems under fluctuating load conditions.     

The interactive use of a video database in teacher education: Creating a knowledge base for teaching through a learning community

This study explores how pre-service student teachers acquired knowledge of good teaching practices through the interactive use of a video database and an online discussion forum, where the student teachers shared their teaching videos and received comments or suggestions from members of a learning community. A small group of student teachers was involved in this collaborative learning community during their teaching practicum in their third and fourth years of study. Content analysis of the sharing in the discussion forum and individual student teacher reflections provides insight into the use of a collaborative learning community to create a knowledge base for teaching. Suggestions regarding how this new technology can support teacher education are discussed.     

Optimal strategies for maintaining a chain of relays between an explorer and a base camp

We envision a scenario with robots moving on a terrain represented by a plane. A mobile robot, called explorer is connected by a communication chain to a stationary base camp. The chain is expected to pass communication messages between the explorer and the base camp. It is composed of simple, mobile robots, called relays.     

A vEB-tree-based architecture for interactive video on demand services in peer-to-peer networks

To provide interactive operations such as random seeking for peer-to-peer on demand video streaming is a challenge. In this paper, a vEB-tree (van Emde Boas tree)-based architecture is proposed for interactive VoD services in peer-to-peer networks. The proposed architecture divides a video into many segments that are distributed among participating peers. In this architecture, it includes a vEB-tree-based topology, searching procedures for demand segments, and a segment distribution scheme. It not only efficiently provides interactive operations but also reduces control messages. Additionally, each peer stores segments based on the proposed segment distribution scheme to reduce server stress. Experimental results demonstrate that the proposed architecture outperforms other competing architectures in terms of jump latency, server stress, and cost of maintaining searching topology.     

MANIP: an interactive tool for modelling RNA

Large RNA structures can be viewed as assemblies of smaller units or modules that are usually clearly identified (helices, hairpin loops, other recurrent motifs, etc.). We have developed a program, MANIP, which allows the rapid assembly of separate motifs (each with a specified sequence) into a complex three-dimensional architecture. The already determined modules are present in a database from which they can be extracted with the appropriate sequence. Their assembly is performed in real time on the computer screen with buttons and dials that command rotation and translation of any chosen fragment with respect to the chosen pivot, or that generate all possible variations of any torsion angle within a specified segment either in the 5′ or in the 3′ direction. The possible in-built manipulations follow the general stereochemical rules of RNA structure. MANIP automatically recognizes and displays the allowed and nonallowed hydrogen bonds between the residues. The program is interfaced with a rapid and automatic online refinement tool of partial or full assemblies, NUCLIN-NUCLSQ. The refinement protocol incorporates canonical as well as noncanonical base pairing constraints together with restraints imposed by covalent geometry, stereochemistry, and van der Waals contacts. The computer package runs on UNIX Silicon Graphics workstations and is written in C with OpenGL and X11/Motif libraries.     

V-HairStudio: an interactive tool for hair design

Graphical models of natural objects have become increasingly complex and sophisticated. Although researchers have made significant progress in modeling complex objects in the last decade, representing human hair realistically continues to challenge us. It presents problems in all aspects of computer graphics technologies, such as shape modeling, manipulation, rendering, and dynamic simulation. The article introduces a hair-designing system. Based on the cluster hair model, this designing tool provides a rich set of functionality for interactive hairstyle design in two levels of abstraction. The system is more powerful, and at the same time, more convenient and efficient for hair styling and manipulation than previous modeling systems. We can divide existing hair models into two categories: explicit geometric models and volume-density models     

Interactive video technology: Enhancing professional learning in initial teacher education

The University of Sussex In-School Teacher Education Project (InSTEP) uses interactive video technologies to enhance initial teacher education programmes for science trainee teachers. With four Internet Protocol cameras and mounted microphones in both school laboratories and the university teaching room, trainees and their tutors have access to live interaction with schools. This paper presents some of the findings of a 2 year evaluation of InSTEP aimed at identifying the benefits for trainee teachers. There has been an increase in the use of video material for teacher training purposes, however, trainee teachers are often intimidated by carefully selected extracts featuring experienced teachers. InSTEP activities are live and capitalise on all the opportunities associated with normal classroom practice. Literature points to InSTEP-type activities having the potential to enhance the development of trainees’ observation skills, develop reflective thinking, to provide authentic illustrations of classroom practice, enable remote observation and facilitate the coaching of trainees by mentors. A fourth generation model of evaluation was undertaken with data generated by semi-structured interviews with university tutors and mentors supported by a questionnaire and group interviews with the trainees. Our main findings point to InSTEP enhancing and accelerating the growth of trainee teachers’ professional knowledge through enabling reflective practice, facilitating collaborative learning and supporting the development of the language of pedagogy.