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Unique decodability is the essential feature of any coding scheme, which is naturally provided by prefix-free codes satisfying the Kraft-McMillan inequality. Non-prefix-free codes have received much less attention due to the lack of an efficient method to support this property. In this study we introduce a novel technique that uses wavelet trees to bring unique decodability to non-prefix-free codes...
A new computational technique is presented for determining rate regions for coded networks. The technique directly manipulates the extreme ray representation of inner and outer bounds for the region of entropic vectors. We use new inner bounds on region of entropic vectors based on conic hull of ranks of representable matroids. In particular, the extreme-ray representations of these inner bounds are...
In this paper, the implementation of a Multi-DSP based video decoder compliant with the H.264/SVC standard (14496-10 Annex G) is presented. An optimized single DSP-based decoder implementation has been splitted in two processes: the frame decoding (entropy decoding and motion compensation) and the deblocking filter. A multi-DSP device has been used to parallelize the execution of the processes. The...
We analyze the asymptotic performance of non-binary spatially-coupled low-density parity-check (SC-LDPC) codes built on the general linear group, when the transmission takes place over the binary erasure channel. We propose an efficient method to derive an upper bound to the maximum a posteriori probability (MAP) threshold for nonbinary LDPC codes, and observe that the MAP performance of regular LDPC...
In the research of time varying communication channels, signal amplitude attenuation is considered to be the main cause of channel varying memories. The Gilbert-Elliot channel has been used to model this kind of memories for a long time with a decision-feedback decoder or an equivalent genie-aided decoder being its optimal decoders.
In this paper we propose a general biometric cryptosystem framework inspired by the code-offset sketch. Specifically, the properties of digital modulation and turbo codes with soft-decoding are exploited to design a template protection system able to guarantee high performance in terms of both verification rates and security, also when dealing with biometrics characterized by a high intra-class variability...
This paper proposes an information hiding scheme based on the Context-based Adaptive Variable Length Coding (CAVLC) mode of entropy encoding in H.264/AVC video encoding standard. The scheme hides information in the process of encoding the trailing coefficient in CAVLC, just in luminance (luma) components of 4x4 DCT data blocks. By modifying the check sum of codeword encoded for the trailing coefficient...
We consider the problem of efficient and lossless representation of a multiset of m words drawn with repetition from a set of size 2n. One expects that encoding the (unordered) multiset should lead to significant savings in rate as compared to encoding an (ordered) sequence with the same words, since information about the order of words in the sequence corresponds to a permutation. We propose and...
The adaptation of intensive calculation algorithms made the new emerging H.264 an efficient video codec. On the other hand, embedded processors are equipped with multicore processors, thus offering additional processing power. The H.264 codec cannot benefit from this processing power in its current state. One solution is to execute the codec on different cores concurrently. H.264 codec is a complex...
We suggest an approach to constructing low-redundant RLL (d; k)-codes whose complexity does not depend on the code length and is determined solely by the achievable redundancy r, the time and space complexity being O(log2(1/r)) and O(log(1/r)), respectively, as r → 0. First we select code-words whose combinations may constitute all (d; k)-constrained sequences of any length. Then we use arithmetic...
The application of polar coding to rate-adaptive asymmetric Slepian-Wolf coding is considered. The encoder transmits the syndrome set which includes high entropy bits to the decoder to achieve the optimal compression. It means that the encoder must know the correlation between two sources and the syndrome set varies according to this correlation. In this paper, we propose polar source coding scheme...
Our paper studies customer value of e-commerce from two different points of view based on grounded theory and tries to conduct large amount of data in e-commerce with our model. The customer value model of e-commerce is built up through analyzing the relationship of categorizations and conceptions selected by grounded theory. After that, the evaluation value model is built up by proposing three measurements:...
In the past years, research and industry have introduced several parallel programming models to simplify the development of parallel applications. A popular class among these models are task-based programming models which proclaim ease-of-use, portability, and high performance. A novel model in this class, OpenMP Superscalar, combines advanced features such as automated runtime dependency resolution,...
This paper investigates a new method in proving converses in secure communication problems. The method gives a converse result in terms of the logarithm of support size instead of entropy. The results are connected to constrained information inequalities involving three random variables. A new constrained non-Shannon type inequality is shown.
Functional dependence graphs (FDG) are an important class of directed graph that capture the functional dependence relationship among a set of random variables. FDGs are frequently used in characterizing and calculating network coding capacity bounds. However, the order of an FDG is usually much larger than the original network and the complexity of computing bounds grows exponentially with the order...
We present a novel lossy compression approach for point cloud streams which exploits spatial and temporal redundancy within the point data. Our proposed compression framework can handle general point cloud streams of arbitrary and varying size, point order and point density. Furthermore, it allows for controlling coding complexity and coding precision. To compress the point clouds, we perform a spatial...
Randomized (dithered) quantization is a method capable of achieving white reconstruction error independent of the source. Dithered quantizers have traditionally been considered within their natural setting of uniform quantization. In this paper we extend conventional dithered quantization to nonuniform quantization, via a subterfage: dithering is performed in the companded domain. Closed form necessary...
In this paper we propose and evaluate a parallelization strategy for the emerging HEVC video coding standard. The proposed strategy is based on entropy slices which allows exploiting parallelism in the entropy decoding stage while maintaining high coding efficiency. Our approach requires to encode videos with one entropy slice per LCU row in order to decode multiple LCU rows in a wavefront parallel...
We consider the problem of code design for compression of correlated sources under adversarial attacks. A scenario with three correlated sources is considered in which at most one source is compromised by an adversary. The theoretical minimum achievable sum-rate for this scenario was derived by Kosut and Tong. We design layered LDPC convolutional codes for this problem, assuming that one of the sources...
The orthodoxy in the time-varying channel is that, the mutual information (MI) rate of the Uniform Symmetric Variable Noise Finite State Markov Channel (USVN-FSMC) is maximized by the channel input of maximum entropy, i.e., independent and identically distributed (i.i.d.) and uniform. The optimal signal detection is performed by a decision-feedback decoder (DFD). However this decoder is not reliable;...
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