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IEEE International Conference on Image Processing

作者： Z. Wang S. Simon M. Klaiber S. Ahmed Th. Richter Department of Parallel Systems University of Stuttgart Stuttgart Germany RUS Computing Center University of Stuttgart Stuttgart Germany

A spatial domain perceptual image codec based on sub-sampling and perceptual quantization (SSPQ) guided by the just-noticeable distortion (JND) profile is proposed. SSPQ integrates perceptual image coding and progressive transmission in one framework. The input image is first subsampled by a factor of two in both dimensions and the subsampled image is compressed without loss. The subsampled image provides a basis for both predicting the input pixels by interpolation and estimating the JND values for each pixel. Residual quantization thresholds are set to the estimated JND values for a perceptually tuned compression. Quantized residuals are progressively encoded by a context-based Golomb coder with run-length coding capacity. Experimental results show over 50% improvement in compression performance on average for the proposed SSPQ codec compared to the lossless JPEG-LS.

关键词： Image coding Quantization Codecs Estimation Encoding Decoding compression algorithms

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Simulation study on code attestation with compressed instruction code

Simulation study on code attestation with compressed instruc...

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IEEE Annual Conference on Pervasive Computing and Communications Workshops (PerCom)

作者： Benjamin Vetter Dirk Westhoff Department of Computer Science Hamburg University of Applied Sciences Hamburg Germany

Available purely software based code attestation protocols for wireless sensor nodes have recently been shown to be cheatable. For instance, an attacker can gain free space within a node's program memory through a so called compression attack to subsequently inject a bogus code image, compromising the node. In this work we propose and implement a code attestation protocol that uploads yet compressed instruction code to a node during deployment. The code image is loaded compressed to raise and subsequently detect the overhead of attacks aiming to inject bogus code into a node's program memory. The described secure code attestation protocol makes use of proposed micro-controller architectures for reading out compressed instruction code.

关键词： Image coding Protocols compression algorithms Memory management Software Wireless sensor networks Security

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Polylog Space compression, Pushdown compression, and Lempel-Ziv Are Incomparable

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THEORY OF COMPUTING SYSTEMS 2011年第4期48卷 731-766页

作者： Mayordomo, Elvira Moser, Philippe Perifel, Sylvain Univ Zaragoza Dept Inform & Ingn Sistemas Inst Invest Ingn Aragon I3A Zaragoza 50018 Spain Natl Univ Ireland Maynooth Dept Comp Sci Maynooth Co Kildare Ireland Univ Paris 07 CNRS LIAFA Paris France

The pressing need for efficient compression schemes for XML documents has recently been focused on stack computation (Hariharan, S., & Shankar, P. in: Proceedings of the 2006 IEEE data compression conference, p. 453, 2006;League, C., & Eng, K. in: Proceedings of the 2007 IEEE data compression conference, pp. 272-282, 2007), and in particular calls for a formulation of information-lossless stack or pushdown compressors that allows a formal analysis of their performance and a more ambitious use of the stack in XML compression, where so far it is mainly connected to parsing mechanisms. In this paper we introduce the model of pushdown compressor, based on pushdown transducers that compute a single injective function while keeping the widest generality regarding stack computation. We also consider online compression algorithms that use at most polylogarithmic space (plogon). These algorithms correspond to compressors in the data stream model. We compare the performance of these two families of compressors with each other and with the general purpose Lempel-Ziv algorithm. This comparison is made without any a priori assumption on the data's source and considering the asymptotic compression ratio for infinite sequences. We prove that in all cases they are incomparable.

关键词： compression algorithms Plogon Computational complexity Data stream algorithms Lempel-Ziv algorithm Pushdown compression

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Key Technologies and Optimization for Dynamic Migration of Virtual Machines in Cloud Computing

Key Technologies and Optimization for Dynamic Migration of V...

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International Conference on Intelligent System Design and Engineering Application (ISDEA)

作者： Jing Yang

Clouds computing, as the latest IT operating model in the Internet Age, is an innovative information system (IS) architecture. Virtualization technology, being the most effective solution to the resource management of cloud computing, excels in its virtual machine real-time migration technology. In order to reduce the migration downtime, Magician optimization migration framework is proposed, based on the analysis of the memory transfer in the real-time migration of current Xen virtual machine. Layered copy module and memory compression module are added to the operation migration module of the typical Xen virtual machine, while layered copy algorithm and memory compression algorithm are also proposed respectively. The test analysis shows that Magician optimizes the time and space complexity of realizing real-time transfer, thus to improve migration performance of the virtual machine.

关键词： Virtual machining Cloud computing Optimization Real time systems Monitoring Algorithm design and analysis compression algorithms

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The embedding of Arabic characters in QR code

The embedding of Arabic characters in QR code

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IEEE Conference on Open Systems (ICOS)

作者： Mohammad Farizshah Ismail Kamil Kamarularifin Abd Jalil Faculty of Computer and Mathematical Sciences Universiti Teknologi MARA Shah Alam Selangor Darul Ehsan Malaysia

Since the introduction of QR Codes in the 90's, many companies have developed QR Code generators and mobile applications to read QR Codes. Despite the obvious benefits of next-generation data transfers, they have yet to be widely accepted and practiced. One of the main reasons is the use of unique language characters such as Arabic characters, Japanese Kanji, Thai Abugida and so forth. An attempt at embedding Arabic characters into QR Code for example, will result in the character's Unicode representation to be automatically encoded and/or decoded by default, instead of the original alphabet as a result of a method called Romanization. Thus, the intended use of the generated code has been useless. It is also noted that Romanization causes each character to be encoded in its own unique codeword which devours more space than encoding it with codeword for character combinations. In order to help solve this problem, this paper proposes the use of an algorithm that compares each word from an Arabic input with an internal codeword library that will then select the shortest codeword possible for single character and two-character combinations to replace the default Unicode representation, which also serves as a space saving method that allows longer messages to be encoded in a single QR Code. In return, the same method is also used to properly decode the message.

关键词： Encoding Standards Reed-Solomon codes Libraries compression algorithms Computers

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A New Hearing Aid Fitting Strategy for Severe to Profound Hearing Loss

A New Hearing Aid Fitting Strategy for Severe to Profound He...

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ITG-Fachtagung Sprachkommunikation

作者： Tobias Herzke Sabine Haumann Volker Hohmann HorTech gGmbH Medizinische Hochschule Hannover Universitat Oldenburg

ISBN: (纸本)9783800734559

A new fitting strategy for severe to profound hearing loss is proposed. This fitting strategy is based on the Cambridge Formula for multichannel compression [2]. The formula has been modified so that it takes into account that amplification may not support or even hamper hearing at certain frequencies. The new fitting strategy was evaluated by aided speech intelligibility tests. For 35 subjects, the new fitting strategy was compared with the subjects' own hearing aids through speech intelligibility tests. The same tests were performed with 20 ears of severe hearing-impaired test subjects outside of a clinical setting. For these ears, the new fitting strategy was compared with NAL-NL1 implemented on the same dynamic compression algorithm and with own hearing aids. The new fitting strategy performs well for the profound hearing impaired. For the severe hearing impaired, however, no improvement could be found. Some shortcomings of the new fitting strategy have been identified and improvements are suggested.

关键词： Hearing Disorders Speech Intelligibility MACHINE SHOP PRACTICE Grade 3 Severe Adverse Event Hearing Aids compression algorithms

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A new techniques for optimizing the web search engines

A new techniques for optimizing the web search engines

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International Conference on Fuzzy Systems and Knowledge Discovery (FSKD)

作者： Shu Zhang Hui Li Cun-hua Li Yun Hu Xia Wang School of Business Huaihai Institute of Technology Lianyungang China Department of Computer Sciences Huaihai Institute of Technology Lianyungang China

A Web search engine must update its index periodically to incorporate changes to the Web. Query processing is a major cost factor in operating large web search engines. To solve this problem, we propose a framework for optimizing the search result by combing inverted index compression and feature-based caching. We perform a comparison and evaluation of several inverted compression algorithms. We then set a new feature-based eviction policies that achieve significant improvements over previous methods. Experimental results shows that this approach can achieve hit rate improvements.

关键词： Indexes Search engines Engines Web search Query processing compression algorithms Encoding

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On the maximum redundancy of CSE for I.I.D. sources

On the maximum redundancy of CSE for I.I.D. sources

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International Symposium on Information Theory and Its Applications, ISITA

作者： Ken-ichi Iwata Mitsuharu Arimura Yuki Shima Graduate School of Engineering University of Fukui Fukui-shi Fukui Japan Department of Applied Compute Sciences Shonan Institute of Technology Fujisawa-shi Kanagawa Japan

Dubé and Beaudoin proposed a new technique of lossless data compression called compression via substring enumeration (CSE) in 2010. We present an upper bound of the amount of bits used by lossless compression via the CSE technique to encode any given binary string from the class of independent and identically distributed (i.i.d.) sources. We compare the worst case maximum redundancy obtained by the CSE technique with the least possible value of the worst case maximum redundancy obtained by the best fixed-to-variable length code satisfying the Kraft inequality. We also consider the optimality of the CSE code from the view point of overflow and underflow probabilities.

关键词： Redundancy Encoding Data compression Educational institutions compression algorithms Upper bound

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Adaptive segmentation of DNA sequences using SBC Technique: A novel Algorithm

Adaptive segmentation of DNA sequences using SBC Technique: ...

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International Conference on Computing and Networking Technology (ICCNT)

作者： V. Hari prasad P.V. Kumar D. Vasumathi Jawaharlal Nehru Technological Jawaharlal Nehru Technological University Andhra Pradesh India Osmania University Hyderabad Andhra Pradesh India Department of CSE JNTU CEH Hyderabad Andhra Pradesh India

ISBN: (纸本)9781467356930

Availability of more and more DNA sequences in the biological databases their size is exponentially growing and it is very hard to maintain and process such data in intra and internetworking systems. Hence need of compression is playing a predominant role in the real vogue. In this connection many algorithms are arrived but some of them achieved bountiful and others are not due to specificity of text encoded in a DNA. Performance analysis is developed based on repetitive and non repetitive sequences of bases in DNA. Existing algorithms may run in Best case if the sequence may contains tandem repeats and compression ratios are computed in terms of bits per bases. Our proposed SBC (splinter Binary compression) technique is developed based on the comparative study of existing techniques and it achieves one of best compression ratios in an average of 1.142 bits/bases which is on par existing techniques. In addition to if we can apply of our technique on both repetitive and non repetitive sequences of genomes also it may give same compression rate in an average in all the cases Definitely our one will become one of the lossless in valuable technique in bio informatics era.

关键词： DNA Genomics Bioinformatics Image coding Educational institutions Biological information theory compression algorithms

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Large Scale Field Trial Results on Frequency Domain compression for Uplink Joint Detection

Large Scale Field Trial Results on Frequency Domain Compress...

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Institute of Electrical and Electronics Engineers Globecom Workshops

作者： Michael Grieger Stefan Boob Gerhard Fettweis Technische Universitat Dresden Vodafone Chair Mobile Communications Systems

ISBN: (纸本)9781467349420

The spectral efficiency of cellular communication systems is limited by inter-cell interference. Especially cell edge users will experience bad performance. A potential remedy to inter-cell interference is joint signal processing on the base station (BS) side. In the cellular uplink the received signals of multiple BSs can be processed at a central node, referred to as joint detection (JD). Field trials of this technique verify large improvements in spectral efficiency and fairness which were initially proven in theoretical and simulation studies. Recent studies encourage that JD is even beneficial under stringent backhaul constraints which are likely to occur in real deployments. The general solution in case of limited backhaul capacity is based on the compression of exchanged signals. This paper presents the most significant design criteria of such compression algorithms for an LTE-Advanced system. We focus on the exchange of frequency domain IQ-symbols. The limits and potentials of a comprehensive system solution are evaluated using data from large scale field trials.

关键词： spectral efficiency compression algorithms inter-cell interference DESIGN CRITERIA JULIAN DATE cellular mobile system up link Set of central axillary lymph nodes field experimentation Frequency-domain analysis received signal return stroke Joints Joints signal processing

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