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IEEE Symposium on Computers and Communications (ISCC)

作者： B. Ozden R. Rastogi A. Silberschatz Bell Laboratories Lucent Technologies Inc. Murray Hill NJ USA

The following are two possible approaches to providing database functionality for multimedia data: a) the multimedia data as well as the metadata for it is stored together in a single database system, and b) the multimedia data is stored in a separate file system while the corresponding metadata for it is stored in a database system. Both approaches have their advantages and disadvantages. The first approach implies that databases need to be redesigned to support multimedia data along with conventional data. Since this requires modifications to existing databases, businesses may not be convinced to replace their databases with a new one to accommodate multimedia. Furthermore, this integrated approach might be a burden for users who do not need full-fledged multimedia support. The second approach allows businesses to capitalize on their existing base and purchase a multimedia storage system and the necessary glue to integrate their databases with the multimedia storage system. This approach, however, may complicate the implementation of some of the database functionality such as data consistency. The authors provide an overview of a) the issues for supporting content-based queries and a brief survey of research done in this arena, and b) the issues related to the storage and retrieval of continuous media data.

关键词： Multimedia databases Multimedia systems File systems Image databases Video compression Transform coding compression algorithms Timing Image storage Resource management

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A comparative study of lossless coding techniques for screened continuous-tone images

A comparative study of lossless coding techniques for screen...

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International Conference on Acoustics, Speech, and Signal Processing (ICASSP)

作者： K. Denecker P. de Neve ELIS University of Gent IMEC Gent Belgium

The huge sizes of screened colour-separated photographic images makes lossless compression very beneficial for both storage and transmission. Because of the special structure induced by the half-tone dots, the compression results obtained on the CCITT test images might not apply to high-resolution screened images and the default parameters of existing compression algorithms may not be optimal. In this paper we compare the performance of different classes of lossless coders: general-purpose one-dimensional coders, non-adaptive two-dimensional black-and-white coders and adaptive two-dimensional coders. Firstly, experiments on a set of test images screened under different conditions showed that MGBILEVEL and JBIG perform best with respect to compression efficiency; the difference with the other coders is significant. Secondly, we investigated the influence of the screening method (stochastic or classical screening) and screening resolution on the compression ratio for these techniques.

关键词： Image coding Testing Image storage Printing Image resolution Stochastic processes Propagation losses compression algorithms Performance loss Performance evaluation

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An optical flow based motion compensation algorithm for very low bit-rate video coding

An optical flow based motion compensation algorithm for very...

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International Conference on Acoustics, Speech, and Signal Processing (ICASSP)

作者： Shu Lin Y.Q. Shi Ya-Qin Zhang Electrical and Computer Engineering Department New Jersey Institute of Technology Newark NJ USA David Samoff Research Center Inc. Princeton NJ USA

We propose an efficient compression algorithm for very low bit-rate video applications. The algorithm is based on (1) optical-flow motion estimation to achieve more accurate motion prediction fields; (2) DCT-coding of the motion vectors from the optical-flow estimation to further reduce the motion overheads; and (3) a region adaptive threshold technique to match optical flow motion prediction and minimize the residual errors. Unlike the classic block-matching based discrete cosine transformation (DCT) video coding schemes in MPEG 1/2 and H.261/3, the proposed algorithm uses optical flow for motion compensation and the DCT is applied to the optical flow field instead of predictive errors. Thresholding techniques are used to treat different regions to complement the optical flow technique and to efficiently code residual data. While maintaining comparable peak signal to noise ratio (PSNR) and computational complexity with that of ITU-T H.263/TMN5, the reconstructed video frames of the proposed coder are free of annoying blocking artifacts, and hence visually much more pleasant.

关键词： Image motion analysis Motion compensation Adaptive optics Optical noise Motion estimation Discrete cosine transforms PSNR compression algorithms Video compression Video coding

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Error concealment improvements for MPEG-2 using enhanced error detection and early re-synchronization

Error concealment improvements for MPEG-2 using enhanced err...

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International Conference on Acoustics, Speech, and Signal Processing (ICASSP)

作者： S. Aign German Aerospace Research Establishment (DLR) Institute for Communications Technology Oberpfaffenhofen Germany

For digital TV-transmission the video signal has to be highly protected by channel coding, since it is very sensitive to channel disturbances. However, in the case of bad reception conditions, remaining errors in the video signal may still occur. Hence, error concealment techniques might be required at the receiver. The aim of this article is to study different error concealment techniques for MPEG-2 video sequences by exploiting the remaining error-free part of the bitstream as much as possible. This is done by combining an enhanced error detection of the channel decoder with early re-synchronization. In I-pictures, where no motion vectors exist, the gain for early re-synchronization with enhanced error detection compared to other techniques is up to 2.3 dB.

关键词： Decoding Channel coding Error correction Communications technology Protection Video sequences Motion detection Cable TV Satellite broadcasting compression algorithms

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Motion detection on video compressed sequences as a tool to correlate objective measure and subjective score

Motion detection on video compressed sequences as a tool to ...

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International Conference on Digital Signal Processing (DSP)

作者： L. Boch S. Fragola R. Lancini P. Sunna M. Visca RAI Centro Ricerche Torino Italy CEFRIEL Milan Italy Politecnico di Torino Torino Italy

Preliminary results of an attempt at correlation between objective parameters computed on video compressed sequences and subjective scores are reported. The measurement of the objective parameters is performed on sub-areas of the frame singled out taking into account spatial information and motion detection. The results show that the division of the frame into sub-areas can improve correlation performances provided by objective measurements; future planned studies are also reported.

关键词： Performance evaluation Testing Image coding Digital TV Video compression Laboratories Motion measurement Motion detection compression algorithms Production

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Quality of service in heterogeneous distributed systems

Quality of service in heterogeneous distributed systems

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Annual Hawaii International Conference on System Sciences (HICSS)

作者： C. Diot A. Seneviratne I.N.R.I.A. Sophia Antipolis France University of Technology Sydney Australia

The future distributed systems will be very heterogeneous. They will consist of end computing systems with widely varying capabilities, interconnected by networks which offer very different services. Delivering data with a guaranteed level of service is a real problem that requires both support at the network level (integrated services networks) and a QoS (Quality of Service) management environment. This paper describes a simple and flexible approach to QoS management. This approach is based on resource reservation (by the way of traffic control) and application dynamic adaptation. It aims to provide a simple and efficient solution to the best possible quality of transmission considering the level of resource reserved and the current network load. The approach is compared to other classic QoS architectures. It is analysed and evaluated with an experimental implementation in the Internet environment.

关键词： Quality of service Resource management Australia Computer networks Computer architecture Internet Contracts Information management Lead compression algorithms

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Distortion/decoding time tradeoffs in software DCT-based image coding

Distortion/decoding time tradeoffs in software DCT-based ima...

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International Conference on Acoustics, Speech, and Signal Processing (ICASSP)

作者： K. Lengwehasatit A. Ortega Integrated Media Systems Center Department of Electrical Engineering-Systems University of Southern California Los Angeles CA USA

We present a general framework for variable complexity algorithms (VCA) and study the related issue of defining a minimum average complexity implementation. As an example we consider implementations of the inverse DCT (IDCT) which minimize the average computation time by taking advantage of the sparseness of the quantized input data. Since the decoding speed depends on the number of zeros in the input we then present a formulation that enables the encoder to optimize its quantizer selection so as to meet a prescribed "decoding time budget". This leads to a complexity-distortion optimization technique which is analogous to well known techniques for rate-distortion optimization. In our experiments we demonstrate significant reductions in decoding time.

关键词： Decoding Image coding Discrete cosine transforms Application software Rate-distortion Discrete transforms Compaction Availability Hardware compression algorithms

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compression and genetic sequence analysis

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BIOCHIMIE 1996年第5期78卷 315-322页

作者： Rivals, E Dauchet, M Delehaye, JP Delgrange, O UNIV MONS SERV INFORMATB-7000 MONSBELGIUM

A novel approach to genetic sequence analysis is presented. This approach, based on compression of algorithms, has been launched simultaneously by Grumbach and Tahi, Milosavljevic and Rivals. To reduce the description of an object, a compression algorithm replaces some regularities in the description by special codes. Thus a compression algorithm can be applied to a sequence in order to study the presence of those regularities all over the sequence. This paper explains this ability, gives examples of compression algorithms already developed and mentions their applications. Finally, the theoretical foundations of the approach are presented in an overview of the algorithmic theory of information.

关键词： sequence classification regularity detection compression algorithms Kolmogorov complexity

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Constrained ECG compression using best adapted wavelet packet bases

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IEEE SIGNAL PROCESSING LETTERS 1996年第10期3卷 273-275页

作者： Nagarajan, K Kresch, E Rao, SS Kresh, Y MED COLL PENN & HAHNEMANN UNIV PHILADELPHIAPA 19102

The main goal of any electrocardiogram (EGG) compression algorithm is to reduce the bit rate while keeping the signal distortion at a clinically acceptable level, Percentage root mean square difference (PRD), the commonly used figure of merit, does not directly reveal whether the clinically significant ECG waveform information is preserved or not, We present the results of a study of ECG compression using an upper bound on the PRD, This bound is based on the initial performance of the algorithm and could be specified by the clinician after correlating the quality of the compressed versions of the ECG and the resulting PRD.

关键词： Electrocardiography Wavelet packets Root mean square Upper bound Wavelet domain Rate-distortion Lagrangian functions compression algorithms Bit rate Distortion

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Interactive media: An Internet reality

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IEEE SPECTRUM 1996年第4期33卷 29-32页

作者： Comerford, R

While broadcasters test interactive television on small groups of people, millions are working with interactive media each day, using PCs linked to the Internet by phone lines. The activities of this on-line population of today are truly the blueprint for how interactive media will work commercially tomorrow. The author discusses the development of this technology and how it is likely to be used in the future.

关键词： Software algorithms Cable TV Web and internet services Teleconferencing Modems Internet telephony Costs Software maintenance compression algorithms Signal processing

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