John F. Koegel Buford (ed.), "MULTIMEDIA systems", p. 450, ACM Press, New York, Addison-Wesley, Reading, 1994  Home/Search   Document Not in Database   Summary   Related Articles   Check

....will be invoked when the QoS of the video display is too worse that it must switch to another video server. Keywords: distributed video player, network jitter, realtime scheduling 1 Introduction In recent years, a lot of work has been done in the study of distributed video player systems [1, 2, 3, 6]. One of the main issues is how to ensure that the video frames, which are sent from the video server, can arrive and then be displayed on time at the requesting clients so that the display of the video can be maintained at a good quality, e.g. a good quality of services (QoS) Distributed video ....

.... these mechanisms have been shown to be effective in improving the system performance, e.g. to provide a better QoS, they may not be suitable to a replicated distributed video player system which consists of several video servers and the same video may be replicated at different video servers [2]. Replicating the same video at different video servers has several important advantages. Firstly, it is obvious that the system will be more fault tolerant. Secondly, different clients may connect to different video servers even they are requesting the same video. The result is that the ....

J. F. Koegel Buford, Multimedia Systems, ACM Press, New York, 1994.

....a higher tolerance for some un smooth movement in Cartoon since the movements are often artificial. 2.2 Overview of MPEG MPEG was originally designed for storing video and audio on digital media. However, MPEG compression is also suitable for transmitting video frames over computer networks. [4, 5, 10] The basic idea of this compression scheme is to predict motion from frame to frame in the temporal direction, and then to use discrete cosine transforms (DCT) to organize the redundancy in the spatial directions. The MPEG coding scheme is a kind of group frame scheme. In MPEG standard, there are ....

....frame is a B frame, the decoder can simply skip it. However, if the lost or delayed frame is a P frame, the decoder will not be able to reconstruct up to four B frames that are dependent on it. If the lost or delayed frame is an I frame, the entire group of pictures (GAP) cannot be reconstructed. [4, 5, 10, 13] In view of this, the skipping of frames should be taken seriously. 2.3 QoS Frame QoS Frame measures the number of frames displayed on time. Counting the number of frames received and being displayed on time by the client is the only attribute for this measurement of video quality. It assumes ....

J.F. Koegel Buford, Multimedia Systems, Addison Wesley, 1994.

....the iTV from C85W HKTelcom) nevertheless, the demand on transmitting MPEG videos over an uncontrolled network like the Internet is still growing. Because of this demand, a large amount of work has been devoted to the design of distributed video systems for streaming videos over an open network [1 5, 7 8, 19 22, 26, 28, 30]. With an uncontrollable network between the video clients and the server, three most important factors that can improve the video service are: 1. a good transmission scheme on the server side, 2. an efficient and effective buffer management on the client side, and 3. a control mechanism ....

....and the uncontrollable and highly dynamic nature of the Internet traffic. To resolve these problems, a lot of work has been devoted to the design of the transmission schemes and the design of distributed video systems that consider the network congestion when streaming videos over the open network [1 5]. For the VBR transmission schemes, most studies adopted and enhanced the traditional scheduling algorithms and use them for the real time transmission of multimedia data [7 10] Ott et al. 18] and Lain et al. 13] proposed smoothing schemes for the VBR video transmission. Pancha and E1 [19] ....

J. F. Koegel Buford, Multimedia Systems, Addison Wesley, 1994.

....colors is approximated to be the Euclidean distance in a uniform color space [6] RGB is the most commonly used color space model, and is composed of three primary colors Red, Green, and Blue. The primary colors are additive; that is by varying their combinations, other colors can be obtained [7, 13, 23]. The model is visualized as a unit cube (Figure 2) with corners of black, white, the three primary colors (red, green, blue) and the three secondary colors (cyan, magenta, yellow) The color model however bears the limitation that it is not perceptually uniform, meaning that the calculated ....

.... meaning that the calculated distance in the RGB space does not truly correspond to the perceptual color difference [32, 50] The CMY color model is based on the secondary colors of the RGB color space model, that is cyan (green plus blue) magenta (red plus blue) and yellow (red plus green) [7, 13]. The subset of the cartesian coordinate system for the CMY color model is similar to that of the RGB color space, except that the white color occupies the origin (Figure 3) Other colors are obtained by performing either an addition or a subtraction on the white component [23] The color model ....

John F. Koegel Buford. Multimedia Systems. Addison-Wesley Publishing Co. - New York:ACM Press; Reading, Mass., 1994.

.... package may have many different facets through which to interact with users, and software designers typically will select ways of displaying the features of a particular software package in a manner appropriate to its theme and purpose in order to ensure the best possible educational results [1]. Computer aided education has become a popular tool due to its unique characteristics 1) users can determine the pace of the learning progress in accordance with their individual situations and needs; 2) users respond to on screen images or sounds and receive feedback based upon such; 3) a ....

....and reduces the average study time required to master a subject. Per definition, multimedia is the combined use of written words, images, sound, 3 video, animation, and interactive conversation to transmit information. Multimedia helps to ensure that many categories of information are included [1]. Knowledge obtained through multimedia software packages is retained longer than knowledge obtained through traditional means. The effectiveness of multimedia educational tools has already been confirmed by academic professionals and students. The potential fields of application for multimedia ....

Koegel Buford, John F. (1994), Multimedia Systems, Addison-Wesley Publishing Company, New York.

....existing resourcemanagement mechanisms focus on the fairness of the resource assignment, and provide insufficient support for the resource guarantee, enforcement, and observation. Therefore, a new resource management mechanism should be considered as a means of providing appropriate QOS control [5]. In accordance with these requirements, this paper proposes a new QOS control model based on QOS Ticket, and describes the resource management needed to implement the model. A prototype of the QOS Ticket model has been implemented on RTMach, using the system s processor capacity reservation ....

J. F. Koegel Buford et al.: Multimedia systems, Chapter 8, ACM Press SIGGRAPH Series, Addison-Wesley (1994).

....the iTV from C W HKTelcom) nevertheless, the demand on transmitting MPEG videos over an uncontrolled network like the Internet is still growing. Because of this demand, a large amount of work has been devoted to the design of distributed video systems for streaming videos over an open network [1 5, 7 8, 19 22, 26, 28, 30]. With an uncontrollable network between the video clients and the server, three most important factors that can improve the video service are: 1. a good transmission scheme on the server side, 2. an ecient and e ective bu er management on the client side, and 3. a control mechanism between the ....

....and the uncontrollable and highly dynamic nature of the Internet trac. To resolve these problems, a lot of work has been devoted to the design of the transmission schemes and the design of distributed video systems that consider the network congestion when streaming videos over the open network [1 5]. For the VBR transmission schemes, most studies adopted and enhanced the traditional scheduling algorithms and use them for the real time transmission of multimedia data [7 10] Ott et al. 18] and Lam et al. 13] proposed smoothing schemes for the VBR video transmission. Pancha and El [19] ....

J. F. Koegel Buford, Multimedia Systems, Addison Wesley, 1994.

....restricted to specialist applications (bird sounds, whale whistles, etc. and to sound effects (games, movies) so we are left with speech and with music. There are several good textbooks which address issues such as psychoacoustics, the human hearing range, loudness, and the perception of sound [2,3]. For our purposes here all we need to know is that sound is a continuous vibration which is sampled at a given rate which leads to a quantization of the analog waveform into digital format. A higher sampling rate means less quantization noise which means better quality. Audio CD recordings are ....

....typically encountered in speech. Examples of systems which take this approach can be found in [12] 3. Information Retrieval from Digital Video Video is basically a sequence of images relayed at a constant speed, normally 25 to 30 frames per second, with a synchronised audio track. Chapter 5 of [3], has details of analog video fundamentals such as aspect ratio, sync, horizontal and vertical resolutions, frame rates for motion (25 to 30) colour fundamentals (RGB) colour video and TV, video formats and worldwide TV standards such as NTSC in the US, PAL in most of Europe, and SECAM in ....

Koegel Buford, J.F.: Multimedia Systems. ACM Press, Addison-Wesley Publishers, New York (1994).

....have a higher tolerance for some un smooth movement in Cartoon since the movements are often arti cial. 2.2 Overview of MPEG MPEG was originally designed for storing video and audio on digital media. However, MPEG compression is also suitable for transmitting video frames over computer networks. [4, 5, 10] The basic idea of this compression scheme is to predict motion from frame to frame in the temporal direction, and then to use discrete cosine transforms (DCT) to organize the redundancy in the spatial directions. The MPEG coding scheme is a kind of group frame scheme. In MPEG standard, there are ....

....frame is a B frame, the decoder can simply skip it. However, if the lost or delayed frame is a P frame, the decoder will not be able to reconstruct up to four B frames that are dependent on it. If the lost or delayed frame is an I frame, the entire group of pictures (GOP) cannot be reconstructed. [4, 5, 10, 13] In view of this, the skipping of frames should be taken seriously. 2.3 QoS Frame QoS Frame measures the number of frames displayed on time. Counting the number of frames received and being displayed on time by the client is the only attribute for this measurement of video quality. It assumes ....

J.F. Koegel Buford, Multimedia Systems, Addison Wesley, 1994.

....Our terminology is somewhat unusual in that normally the term multimedia object refers to a structured composite of several single media. In fact, HOME uses a black box approach and doesn t address issues such as e.g. synchronisation between different media components of a multimedia object [Buford 94] Biomedical images constitute a subset of the images on our image store (see section 5.2) Currently, this set includes ca. 5900 images, whose specific characteristics (species, sex, stain, etc. are modelled by this subclass. Another subclass of multimedia objects is the class of ....

John F. Koegel Buford. Multimedia Systems. SIGGRAPH Series. ACM Press, 1994.

....offer any session abstractions, but note that such abstractions can be easily layered on top of it. The platform and platform abstractions will support multicast only in a future version. 3.5. IMA The multimedia systems services architecture defined by the Interactive Multimedia Association [12][13] is a layer of abstraction constructed above the multimedia relevant hardware and software resources of a distributed system. As such it constitutes a framework of middleware rather than a platform. It is thought to be used as the media control part of platforms that include in addition ....

J. F. Koegel Buford,"Multimedia Systems", pp221-244, Addison-Wesley Publishing Company, New York, 1994.

....of the presentation of the streams. o11 o12 o13 Time slides audio o21 o22 o23 o24 Figure 1: A presentation of streams. 1. 1 Related Work Several books with respect to multimedia have addressed the issue of synchronization as one of the most important research issues in multimedia research [Buf94, Fur96b, Fur96a, SN95] Studies have investigated the modeling of the synchronization aspects of multimedia data from a conceptual perspective, including graphical models, Petri Net based models, object oriented models, and temporal abstraction models [Tom89, DC91, LG90b, SF89, Mas91, GBT94] ....

John F. Koegel Buford. Multimedia Systems. Addison-Wesley Publishing Company, 1994.

....context are time dependency of data, interactivity of multimedia applications, high data volume, data modelling primitives, and device management. For a general introduction to the basics of multimedia systems and their technical demands in general the reader is referred to e.g. Fur94, Gro94, Buf94, oF94] 3.1 Types of Multimedia Data In the following we briefly characterize the different types of data that are characteristic for multimedia systems. Text: The representation type Text quite often is reduced to represent strings of characters. But a useful representation of textual ....

J. F. Koegel Buford. Multimedia Systems. Addison-Wesley, 1994.

....of composite objects. Other studies [45, 28, 37] concentrate on the networking aspects of a geographically distributed system and propose techniques to support the temporal relationships of a composite object when displayed at a remote client. A survey of these studies is presented in [7, 37]. The relation between our previous works ( 41, 8] on composite objects and this study is discussed in Sec. 1. ARS might appear to be similar to the problem of real time scheduling of tasks on multiprocessors (from [31, 30] to [26] One might conceptualize a cluster as a processor to reduce ARS ....

John F. Koegel Buford, editor. Multimedia Systems, chapter 7. ACM Press, and Addison-Wesley, 1994.

....as we now know it. For further reading on hypermedia and hypermedia systems we refer the reader to the surveys by Conklin [Conklin 1987]and Tomek et al. Tomek, Khan, Muldner, Nassar, Novak and Proszynski 1991] as well as the texts Hypertext and Hypermedia [Nielsen 1990] and Multimedia Systems [Koegel Buford 1994]. We use the term multimedia system in its widest sense to mean a computer system linking text, graphics (two, three or more dimensional) CAD drawings, animations, video clips and sound, as well as interactive and annotated movies [Jayasinha, Lennon and Maurer 1994] A hypermedia system ....

Koegel-Buford J.: "Multimedia Systems": KoegelBuford Ed., ACM Press, SIGGRAPH Series, New York (1994).

....that take place. The icons are assembled in a structure which is visualised and manipulable by the author. Systems using this paradigm tend to provide more powerful facilities for expressing user interaction than solely structure or time based systems. 3.3.1. Authorware Authorware (chapter 12 of [4], 18] 21] 4 , 34] 36] is a powerful and flexible commercial system for creating interactive multimedia presentations for computer based training and kiosk applications. To create a presentation, icons are selected from a palette and incorporated into a flowchart defining the sequence of ....

....remain procedural however, and there is no way of getting an overview (via a timeline) of which media objects will be played on the screen when. Interactions, on the other hand, can be fairly complex, and go far beyond jump to here commands. 3.3.2. IconAuthor IconAuthor (chapter 12 of [4], 18] 21] 4 , 34] is a sophisticated commercial package providing a suite of editors for different data types. Objects created by these, and other external editors, can be included in the end presentation, built in the central application builder. This is icon based with flowcharts ....

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J.F. Koegel Buford (ed.) (1994). Multimedia Systems. Addison-Wesley, New York, New York. ISBN 0201 -53258-1.

....of composite objects. Other studies [Ste90, LG90, RR93] concentrate on the networking aspects of a geographically distributed system and propose techniques to support the temporal relationships of a composite object when displayed at a remote client. A survey of these studies is presented in [Buf94, RR93]. In [CGS95] we proposed a technique (buffered sliding) to avoid retrieval contention when scheduling the retrieval of a single binary composite object (i.e. consisting of two atomic objects) belonging to a single media type. This study is a generalization of [CGS95] to support: 1) a mix of ....

John F. Koegel Buford, editor. Multimedia Systems, chapter 7. ACM Press, and Addison-Wesley, 1994.

....conflict with one another (making significant demands on buffering) as will be indicated later. It is this unique aspect of retrieval contention that distinguishes this study from the previous work in both real time scheduling and synchronization in distributed multimedia information systems (See [Buf94] for a survey) However, our results need to be used in conjunction with the past techniques for a complete solution to the problem of displaying composite objects. The general problem of displaying composite objects is a complex one. In this paper, we focus on an important special case of this ....

John F. Koegel Buford, editor. Multimedia Systems. ACM Press, and Addison-Wesley, 1994.

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John F. Koegel Buford (ed.), "MULTIMEDIA systems", p. 450, ACM Press, New York, Addison-Wesley, Reading, 1994

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John Koegel Bufford. Multimedia Systems. Addison-Wesley, 1994.

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J. F. Koegel Buford, editor. Multimedia Systems. Addison--Wesley, 1994.

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Koegel Buford, J.F. ed. Multimedia Systems, Addison-Wesley, New York, NY, 1994.

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KOEGEL BUFORD J. F. , Multimedia Systems, vol. ACM Press, Addison Wesley, , 1994.

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KOEGEL BUFORD J. F. , Multimedia Systems, vol. ACM Press, Addison Wesley, , 1994.

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John F. Koegel Buford. Multimedia Systems. SIGGRAPH Books. ACM Press, New York, 1994.

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