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Pitch-shifting audio signals using sparse atomic approximations

Pitch-shifting audio signals using sparse atomic approximati...

1st ACM Workshop on Audio and Music Computing for Multimedia, AMCMM'06, co-located with the 2006 ACM International Multimedia Conference

作者： Sturm, Bob L. Daudet, Laurent Roads, Curtis Electrical and Computer Engineering University of California Santa Barbara CA United States Laboratoire d'Acoustique Musicale Paris France Media Arts and Technology University of California Santa Barbara CA United States

ISBN: (纸本)1595935010

As a combination of time and frequency modeling,sparse atomic representation provides a means for effective and interesting time-frequency modifications of signals. A drawback is the intensive computation required to find the representation. New tools however greatly speed the process and facilitate experimentation with real signals. We have experimented with the modification of audio signals, specifically pitch-shifting, using sparse atomic approximations found by the matching pursuit algorithm. A na ve approach,where phase is not taken into account, produces surprisingly good results for signals having soft or no *** artifact sounding like amplitude modulation appears however, which we show can be reduced by a phase optimization algorithm. Finally we discuss a more sophisticated approach to time-frequency modifications in general using atomic representations. © 2006 ACM.

关键词： Signal analysis

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A compressor for effective archiving, retrieval, and updating of XML documents

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ACM Transactions on Internet technology 2006年第3期6卷 223-258页

作者： Min, Jun-Ki. Park, Myung-Jae Chung, Chin-Wan Korea University of Technology and Education Korea Advanced Institute of Science and Technology School of Internet-Media Engineering Korea University of Technology and Education Cheonan Chungnam 330-708 Korea Republic of Division of Computer Science Department of Electrical Engineering and Computer Science Korea Advanced Institute of Science and Technology 373-1 Guseong-dong Yuseong-gu Daejeon 305-701 Korea Republic of

Like HTML, many XML documents are resident on native file systems. Since XML data is irregular and verbose, the disk space and the network bandwidth are wasted. To overcome the verbosity problem, research on compressors for XML data has been conducted. Some XML compressors do not support querying compressed data, while other XML compressors which support querying compressed data blindly encode tags and data values using predefined encoding methods. Existing XML compressors do not provide the facility for updates on compressed XML data. In this article, we propose XPRESS, an XML compressor which supports direct updates and efficient evaluations of queries on compressed XML data. XPRESS adopts a novel encoding method called reverse arithmetic encoding, which encodes label paths of XML data and applies diverse encoding methods depending on the types of data values. Experimental results with real-life data sets show that XPRESS achieves significant improvements on query performance for compressed XML data and reasonable compression ratios. On average, the query performance of XPRESS is 2.13 times better than that of an existing XML compressor, and the compression ratio of XPRESS is about 71%. Additionally, we demonstrate the efficiency of the updates performed directly on compressed XML data. © 2006 ACM.

关键词： XML

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Low-power group key agreement for heterogeneous wireless networks

Low-power group key agreement for heterogeneous wireless net...

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2006 International Wireless Communications and Mobile Computing Conference, IWCMC 2006

作者： Teo, Joseph Chee Ming Tan, Chik How Ng, Jim Mee Information Communication Institute of Singapore School of Electrical and Electronic Engineering Nanyang Technological University Singapore NISlab Department of Computer Science and Media Technology Gjøvik University College Norway

ISBN: (纸本)1595933069

Heterogeneous wireless networks are gaining popularity as users can be connected to these networks without any cables and even when they are mobile. The high power nodes in heterogeneous wireless networks do not have energy constraints but the user nodes, which can be large in numbers, are usually low power energy constrained devices. Therefore, the GKA protocol used to secure group communications in these networks has to take into consideration both the low power nature of the user nodes and the network size. In this paper, we present an energy efficient and scalable GKA protocol, which uses our proposed Contributory Ring-Centralized (ContRi-Central) group model. Besides providing complexity analysis, we also show the computational and communication energy consumption costs analysis of all nodes running our proposed scheme and four other efficient GKA protocols. Both the complexity analysis and energy consumption costs analysis indicate that our proposed scheme is more efficient and suitable for heterogeneous wireless networks. Copyright 2006 ACM.

关键词： Energy efficiency

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Energy-efficient ID-based group key agreement protocols for wireless networks 20

Energy-efficient ID-based group key agreement protocols for ...

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20th IEEE International Parallel and Distributed Processing Symposium, IPDPS 2006

作者： Tan, Chik How Teo, Joseph Chee Ming NISlab Department of Computer Science and Media Technology Gjøvik University College Norway Information Communication Institute of Singapore School of Electrical and Electronic Engineering Nanyang Technological University Singapore 639798 Singapore

ISBN: (纸本)1424400546

One useful application of wireless networks is for secure group communication, which can be achieved by running a Group Key Agreement (GKA) protocol. One well-known method of providing authentication in GKA protocols is through the use of digital signatures. Traditional certificate-based signature schemes require users to receive and verify digital certificates before verifying the signatures but this process is not required in ID-based signature schemes. In this paper, we present an energy-efficient ID-based authenticated GKA protocol and four energy-efficient ID-based authenticated dynamic protocols, namely Join, Leave, Merge and Partition protocol, to handle dynamic group membership events, which are frequent in wireless networks. We provide complexity and energy cost analysis of our protocols and show that our protocols are more energy-efficient and suitable for wireless networks. © 2006 IEEE.

关键词： Wireless telecommunication systems

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Design of limited buffer size for storing multiple reference frames in a video codec

Design of limited buffer size for storing multiple reference...

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IEEE Region 10 Conference (TENCON 2005)

作者： Chen, Chih-Chang Chen, Sheng-Shiung Chen, Oscal T. -C. Chen, Chien-Fa Chen, Fang-Chu Signal and Media Laboratories Dept. of Electrical Engineering National Chung Cheng Univ. Taiwan Digital Signal Processing Tech. Dept. Computer and Communications Research Lab. Industrial Technology Research Institute Taiwan

ISBN: (纸本)9780780393110

Multiple reference frames are recommended for motion estimation and compensation to provide coding efficiency and error concealment in video codecs. However, multiple reference frames take more hardware cost than one reference frame used in the conventional video codecs. Hence, there is a need to reduce the memory size for storing multi-frames. In this work, we look closely at a MacroBlock (MB) of the currently decoded frame to determine the data type, compressed or reconstructed one, for storing itself, according to the coding parameters of blocks in this MB. In addition, the computational Complexity and Memory-required Distribution (CMD) of currently decoded frame is explored in a Group Of Picture (GOP). According to CMD, the computational complexity is minimized by means of making a full use of the given memory size. Furthermore, when the given memory size is insufficient, the signal concealment scheme is utilized to enables MEBs being stored as near-end motion vectors without residuals. Experimental results reveal that the proposed scheme can effectively constrain the memory usage under a given memory size for storing five reference frames as full as possible. In addition, because adequately allocating the buffer size to store the currently decoded frame, a fairly good video quality can be achieved as compared to the conventional work using re-compression schemes for storing reference frames.

关键词： Image coding

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Service restoration considering load balancing in distribution

Service restoration considering load balancing in distributi...

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作者： Choi, Sang-Yule Cha, Jae-Sang Yoon, Chang-Dea Shin, Myong-Chul Dept.of Electronic Engineering Induk Institute of Technology San 76 Wolgye-dong Nowon-gu Seoul Korea Republic of Dept. of Media Technology Seoul National Univ of Technology 172 gongreung 2-dong Nowon-gu Seoul Korea Republic of School of Electrical and Computer Engineering Sungkyunkwan University Suwon 440-746 Korea Republic of

ISBN: (纸本)9783902661081

Service restoration is an emergency control in distribution control centers to restore out-of-service area as soon as possible when a fault occurs in distribution networks. therefore, it requires fast computation time and high quality solutions for load balancing. In this paper. a load balance index and heuristic guided best-first search are proposed for these problem. The proposed algorithm consists of two parts. One is to set up a decision tree to represent the various switching operations available. Another is to identify the most effective the set of switches using proposed search technique and a feeder load balance index. Test results on the KEPCO's 108 bus distribution system show that the performance is efficient and robust. Copyright © 2006 IFAC.

关键词： Decision trees

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SimPort: A multiplayer management game framework 9

SimPort: A multiplayer management game framework

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9th International Conference on computer Games: AI, Animation, Mobile, Educational and Serious Games, CGAMES 2006

作者： Warmerdam, Jeroen Knepflé, Maxim Bidarra, Rafael Bekebrede, Geertje Mayer, Igor Faculty of Electrical Engineering Mathematics and Computer Science Delft University of Technology P.O.Box 5031 Delft2600 GA Netherlands Tygron - Serious Gaming and Media Brasserskade 50 Delft2612 CE Netherlands Faculty of Technology Policy and Management Delft University of Technology P.O. Box 5015 Delft2600 GA Netherlands

ISBN: (纸本)0954901622

The serious games industry needs game engines, or frameworks, that have been developed specifically with this sector in mind. This paper discusses the criteria that such engines need to adhere to in order to support viable solutions. These criteria are illustrated on the basis of SimPort, a novel multiplayer management game framework. SimPort has shown to be very powerful, functional and easy to use in the development of MV2, a game module simulating a major expansion project, the Maasvlakte 2 area, of the Port of Rotterdam in the Netherlands [8]. In addition, from MV2 real-life usage so far, players and tutors have concluded that this game is not only rather educational, but also a lot of fun to play.

关键词： Serious games

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Making Packet Erasures to Improve Quality of FEC-Protected Video

Making Packet Erasures to Improve Quality of FEC-Protected V...

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IEEE International Conference on Image Processing

作者： Ying-zong Huang John G. Apostolopoulos Electrical Engineering & Computer Science Department Massachusetts Institute of Technology USA Streaming Media Systems Group Hewlett Packard Laboratories Palo Alto CA USA

media delivery over lossy packet networks is a challenging problem, and forward error correction (FEC) based techniques are an important technique for overcoming packet loss. Conventional FEC-based media delivery techniques protect all packets equally, or protect a subset of the packets, or protect different subsets of packets with different levels of protection, e.g., scalable coding with unequal error protection (UEP). This paper proposes an FEC-based technique to maximize the expected received media quality by explicitly discarding packets, when beneficial, in order to provide additional room for FEC. Given knowledge of the importance of each packet, we show that there is a simple and intuitive criterion for the optimal selection of which packets to discard and which to protect, as well as the level of protection, to minimize the expected distortion experienced at the receiver. The proposed approach provides significant gains over the conventional approaches, and these gains are illustrated for the case of sending H.264 coded video data over a packet erasure channel with known packet loss rate.

关键词： Protection Forward error correction Decoding Error correction codes Streaming media computer science Application software Image coding Throughput Propagation losses

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Energy-efficient ID-based group key agreement protocols for wireless networks 06

Energy-efficient ID-based group key agreement protocols for ...

引用

International Symposium on Parallel and Distributed Processing (IPDPS)

作者： Chik How Tan J.C.M. Teo NISlab Department of Computer Science and Media Technology Gjovik University College Norway Information Communication Institute of Singapore School of Electrical and Electronic Engineering Nanyang Technological University Singapore

ISBN: (纸本)9781424400546

One useful application of wireless networks is for secure group communication, which can be achieved by running a group key agreement (GKA) protocol. One well-known method of providing authentication in GKA protocols is through the use of digital signatures. Traditional certificate-based signature schemes require users to receive and verify digital certificates before verifying the signatures but this process is not required in ID-based signature schemes. In this paper, we present an energy-efficient ID-based authenticated GKA protocol and four energy-efficient ID-based authenticated dynamic protocols, namely join, leave, merge and partition protocol, to handle dynamic group membership events, which are frequent in wireless networks. We provide complexity and energy cost analysis of our protocols and show that our protocols are more energy-efficient and suitable for wireless networks.

关键词： Energy efficiency Wireless application protocol Wireless networks Costs Authentication Digital signatures Public key Computational efficiency computer science Power engineering and energy

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SERVICE RESTORATION CONSIDERING LOAD BALANCING IN DISTRIBUTION

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IFAC Proceedings Volumes 2006年第7期39卷 219-224页

作者： Sang-Yule Choi Jae-Sang Cha Chang-Dea Yoon Myong-Chul Shin Dept.of Electronic Engineering Induk Institute of Technology San 76 Wolgye-dong Nowon-gu Seoul Korea Dept. of Media Technology Seoul National Univ of Technology 172 gongreung 2-dong Nowon-gu Seoul Korea School of Electrical and Computer Engineering Sungkyunkwan University Suwon 440-746 Korea

关键词： Service Restoration Load Balancing A Load Balance Index Heuristic Guided Search

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