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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]

This paper proposes a cooperative diversity transmission scheme by superposition coding relaying (SC-relaying) for a wireless system with multiple relays. In this scheme, two layer signals, i.e., signal $${x_1}$$ and $${x_2}$$ , are transmitted from a base station (BS) in the first and the second time slot, while signal $${x_1}$$ is also forwarded from multiple relays to a user in the second time slot. The two layer signals ( $${x_1}$$ and $${x_2}$$ ) meet and superimpose with each other in the air in the second time slot. Then successive interference cancellation (SIC) is used for decoding at the user. In this paper, the optimal power allocation that maximizes the sum throughput of $${x_1}$$ and $${x_2}$$ is first studied. Then the optimal number of selected relays and optimal transmission rate at the BS is derived. Finally the outage probability and diversity gain of the transmission of $${x_1}$$ and $${x_2}$$ is evaluated for system robustness. Simulation results show that the proposed scheme realizes the goal of increasing spectral efficiency and enhancing system robustness. [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]

This paper proposes an ideal rateless codes model to comprehensively describe rateless codes and extends the definition of systematic linear block code to generalized systematic code. Under the proposed model, average delay, maximum disorder, and uniformity recovery entropy are introduced as performance indices to design efficient rateless codes. A novel coding scheme based on two-stage encoding and forward equal probability is proposed to optimize the proposed indices. In the first stage, the first k symbols are encoded, aiming to improve the performance of order recovery, uniformity recovery, and transmission efficiency as much as possible. In the second stage, the remaining infinite symbols are encoded, where the symbols with high degree are used to compensate the symbols loss in the first stage. Simulation results show that the proposed scheme can achieve generalized systematic rateless codes with high probability and also has less average delay and maximum disorder, better capacity achievability, and uniformity recovery performance than Luby trasform (LT) codes and rateless coded symbol sorting algorithm. Besides, the proposed scheme has the aforementioned advantages compared with expending window fountain codes except for uniformity recovery and maximum disorder performance when the erasure rate is higher than about 0.25. Copyright © 2013 John Wiley & Sons, Ltd. [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]

P4 polyphase code is well known in pulse compression technique. For P4 code with length 1000, peak sidelobe level (PSL) and integrated sidelobe level (ISL) are −36dB and −16dB, respectively. In order to increase the performance, there are different reduction techniques to reduce the sidelobes of P4 code. This paper presents a novel sidelobe reduction technique that reduces the PSL and ISL to −127dB and −104dB, respectively. Also, other sidelobe reduction techniques such as Woo filter are investigated and compared with the novel proposed technique. Simulations and results show that the proposed technique produces a better peak side lobe ratio (PSL) and integrated side lobe ratio (ISL) than other techniques. [ABSTRACT FROM AUTHOR]

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]

We propose to use a simple and effective way to achieve secure quantum direct secret sharing. The proposed scheme uses the properties of fountain codes to allow a realization of the physical conditions necessary for the implementation of no-cloning principle for eavesdropping-check and authentication. In our scheme, to achieve a variety of security purposes, nonorthogonal state particles are inserted in the transmitted sequence carrying the secret shares to disorder it. However, the positions of the inserted nonorthogonal state particles are not announced directly, but are obtained by sending degrees and positions of a sequence that are pre-shared between Alice and each Bob. Moreover, they can confirm that whether there exists an eavesdropper without exchanging classical messages. Most importantly, without knowing the positions of the inserted nonorthogonal state particles and the sequence constituted by the first particles from every EPR pair, the proposed scheme is shown to be secure. [ABSTRACT FROM AUTHOR]

Abstract: Reversible data hiding is a method that not only embeds secret data but also reconstructs the original cover image without distortion after the confidential data are extracted. In this paper, we propose novel reversible data hiding scheme that can embed high capacity of secret bits and recover image after data extraction. Our proposed scheme depends on the locally adaptive coding scheme (LAC) as Chang&Nguyen’s scheme and SMVQ scheme. Experimental results show that the compression rate of our proposed scheme is 0.33bpp on average. To embed secret bits we propose the normal-hiding scheme and the over-hiding scheme which have an average embedding rate of 2.01bpi and 3.01bpi, more than that of Chang&Nguyen’s scheme (1.36bpi). The normal-hiding scheme and the over-hiding scheme also has high embedding efficiency of 0.28 and 0.36 on average, which are better than that of Chang&Kieu’s scheme (0.12), Chang&Nguyen’s scheme (0.18) and Chang&Nguyen’s scheme (0.16). [Copyright &y& Elsevier]

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]

This paper proposed a parallel video coding scheme based on MapReduce. It divided the input video sequence into segments and mapped to multiple computers in the form of tasks. After that, it encoded all these tasks in parallel at different computer nodes to achieve better encoding speed. In order to minimize the makespan of a given tasks set and balance the system load, this paper proposed a LBMM algorithm according to the computing capacity and the coding charactertics. The simulated results show the proposed parallel video coding system greatly improves the big volumn video sequence coding efficiency, reduces the average job response time. The LBMM algorithm outperforms Min-Min (minimal-minimal complete time) algorithm and RR (round robin) algorithm using in CloudSim. [ABSTRACT FROM AUTHOR]

Abstract: We propose a novel simultaneous multi-user en/decoder using super-structure fiber Bragg gratings (SFBGs) for multi-channel optical code-division multiple-access (OCDMA) applications. Each channel can generate and recognize codes for users individually. Therefore, the SFBG can make full use of the wavelength resource to enlarge the system capacity. In this paper, a 2-channel, 4-channel and 8-channel en/decoders are designed in a single SFBG with optimized performance for their auto-correlation peak over the maximum wing level ratios and peak over the maximum cross-correlation level ratios being larger than 17 and 10.2dB, respectively. [Copyright &y& Elsevier]

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]

SUMMARY Long term evolution constitutes the next generation cellular network beyond 3G that is designed to support the explosion in demand for bandwidth-hungry multimedia services in wireless networks by providing an extremely high performance radio access technology. To support multimedia broadcast/multicast services (MBMS), long term evolution offers the functionality to transmit MBMS over a single frequency network, where a time-synchronized common waveform is transmitted from multiple cells for a given duration. This enables over-the-air combining, thus significantly improving the spectral efficiency (SE) compared with conventional MBMS operations. In MBMS over a single frequency network transmissions, the achieved SE is mainly determined by the modulation and coding scheme selected. This study proposes and evaluates four approaches for the selection of the modulation and coding scheme. Each approach corresponds to different users' distribution and multimedia traffic conditions. On the basis of SE measurements, we determine the approach that either maximizes or achieves a target SE for the corresponding users' distribution and traffic conditions. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: In a peer-to-peer (P2P) video streaming system, peers not only consume video, but also route it to other peers in the system, where ordinary peers are assumed to have sufficient downlink speed and media capability. This assumption often fails when the P2P system consists of peers that are heterogeneous in their computing power, hardware, and media capability. In this paper, we address a problem of streaming video to mobile devices, which are less capable than ordinary peers. In order to stream video to mobile devices, transcoding is often required to render video suitable for their small display, limited downlink speed, and limited video decoding capability. However, performing transcoding at a single peer is vulnerable to peer churn, which leads to video disruption. We propose interleaved distributed transcoding (IDT), a robust video encoding scheme that allows peers more capable than mobile devices to perform transcoding in a collaborative fashion. IDT is designed in such a way that transcoded substreams are assembled into a single video stream, which can be decoded by any H.264/AVC baseline profile compliant decoder. Extensive simulations and its implementation in a real P2P system demonstrate that the proposed scheme not only reduces computational load at a peer, but also achieves robust streaming in the case of peer failure or packet loss due to adverse wireless channel conditions. We confirm this finding by analyzing the effect of distributed transcoding under peer failure. [Copyright &y& Elsevier]

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]

Abstract: This paper proposes a novel robust video watermarking scheme based on local affine invariant features in the compressed domain. This scheme is resilient to geometric distortions and quite suitable for DCT-encoded compressed video data because it performs directly in the block DCTs domain. In order to synchronize the watermark, we use local invariant feature points obtained through the Harris-Affine detector which is invariant to affine distortions. To decode the frames from DCT domain to the spatial domain as fast as possible, a fast inter-transformation between block DCTs and sub-block DCTs is employed and down-sampling frames in the spatial domain are obtained by replacing each sub-blocks DCT of 2×2 pixels with half of the corresponding DC coefficient. The above-mentioned strategy can significantly save computational cost in comparison with the conventional method which accomplishes the same task via inverse DCT (IDCT). The watermark detection is performed in spatial domain along with the decoded video playing. So it is not sensitive to the video format conversion. Experimental results demonstrate that the proposed scheme is transparent and robust to signal-processing attacks, geometric distortions including rotation, scaling, aspect ratio changes, linear geometric transforms, cropping and combinations of several attacks, frame dropping, and frame rate conversion. [Copyright &y& Elsevier]

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: This paper introduces the establishment of PolyU near-infrared face database (PolyU-NIRFD) and presents a new coding scheme for face recognition. The PolyU-NIRFD contains images from 350 subjects, each contributing about 100 samples with variations of pose, expression, focus, scale, time, etc. In total, 35,000 samples were collected in the database. The PolyU-NIRFD provides a platform for researchers to develop and evaluate various near-infrared face recognition techniques under large scale, controlled and uncontrolled conditions. A new coding scheme, namely directional binary code (DBC), is then proposed for near-infrared face recognition. Finally, we provide three protocols to evaluate and compare the proposed DBC method with baseline face recognition methods, including Gabor based Eigenface, Fisherface and LBP (local binary pattern) on the PolyU-NIRFD database. In addition, we also conduct experiments on the visible light band FERET database to further validate the proposed DBC scheme. [Copyright &y& Elsevier]

Abstract: In this paper, time-spreading wavelength-hopping optical CDMA system using 2-D run-length limited code is investigated. The run-length limited code we use here is predicated upon spatial coding scheme, which can improve system performance significantly. In our proposed system, we employ carrier-hopping prime code and its shifted version as signature sequences. Based on the zero auto-correlation sidelobes property of signature sequence, we propose a two-state trellis coding architecture, which utilizes 2-D parallel detection scheme. The proposed scheme is compact and simple that can be applied to more complicated trellis to further enhance system performance. Multiple access interference is the main deterioration factor in optical CDMA system that affects system performance adversely. Aside from the multiple access interference, some of the adverse impacts of system performance are also taken into consideration, which include thermal noise, shot noise, relative intensity noise, and beat noise. [ABSTRACT FROM AUTHOR]

Abstract: The paper considers a sensor network whose sensors observe a common quantity and are affected by arbitrary additive bounded noises with a known upper bound. During the experiment, any sensor can communicate only a finite and given number of bits of information to the decision center. The contributions of the particular sensors, the rules of data encoding, decoding, and fusion, as well as the estimation scheme should be designed to achieve the best overall performance in estimation of the observed quantity by the decision center. An optimal algorithm is obtained that minimizes the maximal feasible error. It is shown that it considerably outperforms the algorithm proposed in recent papers in the area and examined only in the idealized case of noiseless sensors. [ABSTRACT FROM AUTHOR]

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]