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Privacy protection is the primary concern when RFID applications are deployed in our daily lives. Due to the computational power constraints of passive tags, non-encryption-based singulation protocols have been recently developed, in which wireless jamming is used. However, the existing private tag access protocols without shared secrets rely on impractical physical layer assumptions, and thus they are difficult to deploy. To tackle this issue, we first redesign the architecture of RFID system by dividing an RF reader into two different devices, an RF activator and a trusted shield device (TSD). Then, we propose a novel coding scheme, namely Random Flipping Random Jamming (RFRJ), to protect tags’ content. Unlike the past work, the proposed singulation protocol utilizes only the physical layer techniques that are already implemented. Analyses and simulation results validate our distributed architecture with the RFRJ coding scheme, which defends tags’ privacy against various adversaries including the random guessing attack, correlation attack, ghost-and-leech attack, and eavesdropping. [ABSTRACT FROM AUTHOR]

Although parallelization of computationally intensive algorithms has become a standard with the scientific community, the possibility of in-core vectorization is often overlooked. With the development of modern HPC architectures, however, neglecting such programming techniques may lead to inefficient code hardly utilizing the theoretical performance of nowadays CPUs. The presented paper reports on explicit vectorization for quadratures stemming from the Galerkin formulation of boundary integral equations in 3D. To deal with the singular integral kernels, two common approaches including the semi-analytic and fully numerical schemes are used. We exploit modern SIMD (Single Instruction Multiple Data) instruction sets to speed up the assembly of system matrices based on both of these regularization techniques. The efficiency of the code is further increased by standard shared-memory parallelization techniques and is demonstrated on a set of numerical experiments. [ABSTRACT FROM AUTHOR]

For multi-field simulations involving a larger number of different physical fields and in cases where the involved fields or simulation codes change due to new modelling insights, e.g., flexible and robust partitioned coupling schemes are an important prerequisite to keep time-to-solution within reasonable limits. They allow for a fast, almost plug-and-play combination of existing established codes to the respective multi-field simulation environment. In this paper, we study a class of coupling approaches that we originally introduced in order to improve the parallel scalability of partitioned simulations. Due to the symmetric structure of these coupling methods and the use of 'long' vectors of coupling data comprising the input and output of all involved codes at a time, they turn out to be particularly suited also for simulations involving more than two coupled fields. As standard two-field coupling schemes are not suited for such cases as shown in our numerical results, this allows the simulation of a new range of applications in a partitioned way. [ABSTRACT FROM AUTHOR]

Obtaining a high embedding rate measured in bit per index (bpi) and a low bit rate measured in bit per pixel (bpp) is the main goal of a reversible data hiding scheme in the vector quantization (VQ) compressed domain. This paper proposes a reversible steganographic scheme for VQ indexes based on the joint neighboring coding technique. The proposed method uses the difference values between the current VQ index and the left, upper, top-left neighboring VQ indices, and their combinations to embed n secret bits into one VQ index. The experimental results show that the proposed scheme achieves the different embedding rates of 0.984, 1.969, 2.953, and 3.938 bpi and average bit rates of 0.426, 0.503, 0.571, and 0.634 bpp for n = 1, 2, 3, and 4, respectively. These results confirm that the proposed scheme surpasses other selected reversible data hiding schemes. [ABSTRACT FROM AUTHOR]

Written-in errors (WIEs), which include written-in substitutions, insertions, and deletions, as well as 2-D inter-symbol interference (2-D-ISI), form one of the major challenges for the new emerging bit-patterned media recording technology. Coding and detection scheme with performance/complexity tradeoffs is expected to address such a challenge. In this paper, a new channel model with WIEs and ISI (WIE-ISI) is presented, and the embedded marker code scheme (EMCS) with Bahl-Cocke-Jelinek-Raviv (BCJR) detector is employed to perform channel detection. By investigating the effect of ISI on the WIE-ISI channel considering BCJR detector, a virtual written-in substitution probability is introduced and a new synchronization algorithm with written-in substitution detection (SA-WSD) is developed. The EMCS employing the proposed SA-WSD demonstrates better error correction performance than that of the original SA. Furthermore, the SA-WSD is found to be robust to small estimation errors in the written-in substitution probability. [ABSTRACT FROM PUBLISHER]

In this paper, a new phonetic alphabet called PUNJARPAbet for speech processing in the Punjabi language has been designed. The new phonetic coding scheme PUNJARPAbet developed in this paper has been primarily designed to encode the text and speech corpora recently developed by the authors in the Punjabi language. This recently developed corpus has at least 20 special features. PUNJARPAbet is capable of coding examples related to all special features of the new corpus. PUNJARPAbet is an all upper-case coding scheme and is consistent with the all upper-case version of the famous coding scheme ARPAbet developed by the Advanced Research Projects Agency (ARPA). The new scheme is very easy to follow, and is the most suitable scheme for typing on an ordinary computer keyboard as well as an ordinary typewriter. Unlike many other schemes such as the famous International Phonetic Alphabet ( IPA), the PUNJARAbet is free from the laborious, irritating, and time-consuming necessities for dealing with the special symbols. It has been clearly demonstrated in this paper that PUNJARPAbet is a versatile, efficient and convenient coding scheme for not only the Punjabi language, but also any language which has sounds similar to the ones found in the Punjabi speech. [ABSTRACT FROM AUTHOR]

A coding scheme is proposed for the memoryless Gaussian broadcast channel with correlated noises and feedback. For all noise correlations other than \pm1, the gap between the sum-rate that the scheme achieves and the full-cooperation bound vanishes as the signal-to-noise ratio tends to infinity. When the correlation coefficient is -1, the gains afforded by feedback are unbounded and the prelog is doubled. When the correlation coefficient is +1, we demonstrate a dichotomy that if the noise variances are equal, then feedback is useless, and otherwise, feedback affords unbounded rate gains and doubles the prelog. The unbounded feedback gains, however, require perfect (noiseless) feedback. When the feedback links are noisy, the feedback gains are bounded, unless the feedback noise decays to zero sufficiently fast with the signal-to-noise ratio. Extensions to more receivers are also discussed as is the memoryless Gaussian interference channel with feedback. [ABSTRACT FROM PUBLISHER]

We provide inner and outer bounds on the capacity region for the Gaussian bi-directional relaying over inter-symbol interference channels. The outer bound is obtained by the conventional cut-set argument. For the inner bound, we propose a compute-and-forward coding scheme based on lattice partition chains and study its achievable rate. The coding scheme is a time-domain coding scheme which uses a novel precoding scheme at the transmitter in combination with lattice precoding and a minimum mean squared error receiver to recover linear combinations of lattice codewords. The proposed compute-and-forward coding scheme substantially outperforms decode-and-forward schemes. While it is well known that for the point-to-point communication case, both independent coding along sub-channels and time-domain coding can approach the capacity limit, as a byproduct of the proposed scheme, we show that for the bi-directional relay case, independent coding along sub-channels is not optimal in general and joint coding across sub-channels can improve the capacity for some channel realizations. [ABSTRACT FROM AUTHOR]

We investigate efficient communication over multiple-input multiple-output (MIMO) two-way relay channels (TWRCs), where two multi-antenna users exchange information via a multi-antenna relay. We propose a new MIMO physical-layer network coding (PNC) scheme that includes novel eigen-direction alignment (EDA) precoding. The proposed EDA precoding efficiently aligns the two-user's eigen-modes into the same set of orthogonal directions, and multiple independent PNC streams are implemented over the aligned eigen-modes. We derive an achievable rate-pair of the proposed scheme, for given EDA precoding parameters, over a MIMO TWRC. To maximize the achievable rate-region, we formulate a design criterion for the EDA precoding parameters, and present solutions to the formulation. Closed-form bounds on the sum-rates of the designed EDA-PNC schemes are derived. Numerical results show that there is only a small gap between the achievable rate of the proposed scheme and the capacity upper bound of the MIMO TWRC. It is shown that the proposed scheme can significantly outperforms existing schemes in the literature. [ABSTRACT FROM PUBLISHER]

We develop an information theoretic characterization and a practical coding approach for segmented deletion channels. Compared to channels with independent and identically distributed (i.i.d.) deletions, where each bit is independently deleted with an equal probability, the segmentation assumption imposes certain constraints, i.e., in a block of bits of a certain length, only a limited number of deletions are allowed to occur. This channel model has recently been proposed and motivated by the fact that for practical systems, when a deletion error occurs, it is more likely that the next one will not appear very soon. We first argue that such channels are information stable, hence their channel capacity exists. Then, we introduce several upper and lower bounds with two different methods in an attempt to understand the channel capacity behavior. The first scheme utilizes certain information provided to the transmitter and/or receiver while the second one explores the asymptotic behavior of the bounds when the average bit deletion rate is small. In the second part of the paper, we consider a practical channel coding approach over a segmented deletion channel. Specifically, we utilize outer LDPC codes concatenated with inner marker codes, and develop suitable channel detection algorithms for this scenario. Different maximum-a-posteriori (MAP) based channel synchronization algorithms operating at the bit and symbol levels are introduced, and specific LDPC code designs are explored. Simulation results clearly indicate the advantages of the proposed approach. In particular, for the entire range of deletion probabilities less than unity, our scheme offers a significantly larger transmission rate compared to the other existing solutions in the literature. [ABSTRACT FROM AUTHOR]

\boldmath In this paper, computationally efficient schemes for enumerating the so-called inliers of a wide range of permutations employed in pruned variable-size (turbo) interleavers are proposed. The objective is to accelerate pruned interleaving time in turbo codes by computing a statistic known as the pruning gap that enables determining a permuted address under pruning without serially permuting all its predecessors. It is shown that for any linear or quadratic permutation, including variations such as dithered relative prime or almost regular, the pruning gap can be computed in logarithmic time. Moreover, it is shown that Dedekind sums form efficient building blocks for enumerating inliers of the widely adopted polynomial-based permutations. An efficient algorithm for computing such sums in vector form using integer operations is presented. The results are extended to 2D and higher dimensional interleavers that combine multiple permutations along all dimensions, and closed-form expressions for inliers are derived. It is shown that the inliers statistic is a linear combination of the constituent permutation inliers. A lower bound on the minimum spread of serially pruned interleavers using the inliers statistic is also derived. Moreover, it is shown that serially pruned interleavers inherit the content-free property of the mother interleaver, and hence they are parallelizable. Simulation results of practical pruned turbo interleavers demonstrate a speedup improvement of several orders of magnitude compared to serial interleaving. [ABSTRACT FROM AUTHOR]

Inner and outer bounds are derived on the optimal performance of fixed-length block codes on discrete memoryless channels with feedback and errors-and-erasures decoding. First, an inner bound is derived using a two-phase encoding scheme with communication and control phases together with the optimal decoding rule for the given encoding scheme, among decoding rules that can be represented in terms of pairwise comparisons between the messages. Then, an outer bound is derived using a generalization of the straight-line bound to errors-and-erasures decoders and the optimal error-exponent tradeoff of a feedback encoder with two messages. In addition, upper and lower bounds are derived, for the optimal erasure exponent of error-free block codes in terms of the rate. Finally, a proof is provided for the fact that the optimal tradeoff between error exponents of a two-message code does not improve with feedback on discrete memoryless channels (DMCs). [ABSTRACT FROM PUBLISHER]

An ever more significant fraction of the overall power dissipation of a network-on-chip (NoC) based system-on-chip (SoC) is due to the interconnection system. In fact, as technology shrinks, the power contribute of NoC links starts to compete with that of NoC routers. In this paper, we propose the use of data encoding techniques as a viable way to reduce both power dissipation and energy consumption of NoC links. The proposed encoding scheme exploits the wormhole switching techniques and works on an end-to-end basis. That is, flits are encoded by the network interface (NI) before they are injected in the network and are decoded by the destination NI. This makes the scheme transparent to the underlying network since the encoder and decoder logic is integrated in the NI and no modification of the routers architecture is required. We assess the proposed encoding scheme on a set of representative data streams (both synthetic and extracted from real applications) showing that it is possible to reduce the power contribution of both the self-switching activity and the coupling switching activity in inter-routers links. As results, we obtain a reduction in total power dissipation and energy consumption up to 37% and 18%, respectively, without any significant degradation in terms of both performance and silicon area. [ABSTRACT FROM PUBLISHER]

Abstract: A new scheme of test data compression/decompression, namely coding of even bits marking and selective output inversion, is presented. It first uses a special kind of codewords, odd bits of which are used to represent the length of runs and even bits of which are used to represent whether the codewords finish. The characteristic of the codewords make the structure of decompressor simple. It then introduces a structure of selective output inversion to increase the probability of 0s. This scheme can obtain a better compression ratio than some already known schemes, but it only needs a very low hardware overhead. The performance of the scheme is experimentally confirmed on the larger examples of the ISCAS89 benchmark circuits. [ABSTRACT FROM AUTHOR]

In this work we investigate the problem of simultaneous privacy and integrity protection in cryptographic circuits. We consider a white-box scenario with a powerful, yet limited attacker. A concise metric for the level of probing and fault security is introduced, which is directly related to the capabilities of a realistic attacker. In order to investigate the interrelation of probing and fault security we introduce a common mathematical framework based on the formalism of information and coding theory. The framework unifies the known linear masking schemes. We proof a central theorem about the properties of linear codes which leads to optimal secret sharing schemes. These schemes provide the lower bound for the number of masks needed to counteract an attacker with a given strength. The new formalism reveals an intriguing duality principle between the problems of probing and fault security, and provides a unified view on privacy and integrity protection using error detecting codes. Finally, we introduce a new class of linear tamper-resistant codes. These are eligible to preserve security against an attacker mounting simultaneous probing and fault attacks. [ABSTRACT FROM AUTHOR]

Compression of executable code in embedded microprocessor systems, used in the past mainly to reduce the memory footprint of embedded software, is gaining interest for the potential reduction in memory bus traffic and power consumption. We propose three new schemes for code compression, based on the concepts of static (using the static representation of the executable) and dynamic (using program execution traces) entropy and compare them with a state-of-the-art compression scheme, IBM's CodePack. The proposed schemes are competitive with CodePack for static footprint compression and achieve superior results for bus traffic and energy reduction. Another interesting outcome of our work is that static compression is not directly related to bus traffic reduction, yet there is a trade off between static compression and dynamic compression, i.e., traffic reduction. [ABSTRACT FROM AUTHOR]

Multilevel coding (MLC) provides a low-complexity encoding scheme for lattices obtained via construction D. On the other hand, multistage decoding is also a practical decoding scheme for MLC provided that the underlying error correcting codes are capacity achieving, which requires using a powerful soft decoder for each code. Proposed is an approximation of the log-likelihood ratio (LLR) which used for the soft decoding of the different error correcting codes employed in the lattice construction. This approximation is based on the von Mises distribution and achieves, with lower complexity, the same error rate performance obtained with the exact LLR calculation. [ABSTRACT FROM AUTHOR]

Although random access operations are desirable for on-demand video streaming in peer-to-peer systems, they are difficult to efficiently achieve due to the asynchronous interactive behaviors of users and the dynamic nature of peers. In this paper, we propose a network coding equivalent content distribution (NCECD) scheme to efficiently handle interactive video-on-demand (VoD) operations in peer-to-peer systems. In NCECD, videos are divided into segments that are then further divided into blocks. These blocks are encoded into independent blocks that are distributed to different peers for local storage. With NCECD, a new client only needs to connect to a sufficient number of parent peers to be able to view the whole video and rarely needs to find new parents when performing random access operations. In most existing methods, a new client must search for parent peers containing specific segments; however, NCECD uses the properties of network coding to cache equivalent content in peers, so that one can pick any parent without additional searches. Experimental results show that the proposed scheme achieves low startup and jump searching delays and requires fewer server resources. In addition, we present the analysis of system parameters to achieve reasonable block loss rates for the proposed scheme. [ABSTRACT FROM PUBLISHER]

RFID has been gaining popularity due to its variety of applications, such as inventory control and localization. One important issue in RFID system is tag identification. In RFID systems, the tag randomly selects a slot to send a Random Number (RN) packet to contend for identification. Collision happens when multiple tags select the same slot, which makes the RN packet undecodable and thus reduces the channel utilization. In this paper, we redesign the RN pattern to make the collided RNs decodable. By leveraging the collision slots, the system performance can be dramatically enhanced. This novel scheme is called DDC, which is able to directly decode the collisions without exact knowledge of collided RNs. In the DDC scheme, we modify the RN generator in RFID tag and add a collision decoding scheme for RFID reader. We implement DDC in GNU Radio and USRP2 based testbed to verify its feasibility. Both theoretical analysis and testbed experiment show that DDC achieves 40 percent tag read rate gain compared with traditional RFID protocol. [ABSTRACT FROM PUBLISHER]

In this paper, we study the performance of non-cooperative multiple access systems with noisy separated channels, where correlated sources communicate to an access point (AP) through block-faded links. In the considered scenario, perfect channel state information (CSI) is assumed at the receiver while no CSI is available at the transmitters. We first consider uncoded transmissions from the sources to the AP, which exploits the source correlation to carry out joint channel detection (JCD). In this scenario, we propose an analytical approach to evaluate the achievable performance in terms of average bit error rate (BER). We then investigate the impact of coding, considering the same fixed coding scheme at each source. Then, we consider an extrinsic information transfer (EXIT) chart-based framework to optimize the design of concatenated and low-density parity-check (LDPC) codes for JCD schemes. [ABSTRACT FROM PUBLISHER]