Binary Block Research Articles

Recognition of Facial Expression via Kernel PCA Network

In this work, a kernel principle component analysis network (KPCANet) is proposed for classification of the facial expression in unconstrained images, which comprises only the very basic data processing components: cascaded kernel principal component analysis (KPCA), binary hashing, and block-wise histograms. In the proposed model, KPCA is employed to learn multistage filter banks. It is followed by simple binary hashing and block histograms for indexing and pooling. For comparison and better understanding, We have tested these basic networks extensively on many benchmark visual datasets ( such as the JAFFE [13] database, the CMU AMP face expression database, a part of the Extended Cohn-Kanade (CK+) database), The results demonstrate the potential of the KPCANet serving as a simple but highly competitive baseline for facial expression recognition.

Upper Bounds on the Size of Grain-Correcting Codes

In this paper, we re-visit the combinatorial error model of Mazumdar et al. that models errors in high-density magnetic recording caused by lack of knowledge of grain boundaries in the recording medium. We present new upper bounds on the cardinality/rate of binary block codes that correct errors within this model.

On Optimum Decoding of Certain Product Codes

Optimum decoding of a class of product codes is investigated. The class is the one given by the serial concatenation of a binary single-parity-check code with a low-dimension binary linear block code. It was proved by Wolf that maximum likelihood decoding for this class of product codes can be efficiently performed through the Viterbi algorithm over a compact trellis representation of the code. In this letter, it is showed that the decoding complexity can be further reduced by formulating the decoding problem as a symbol-wise maximum-a-posteriori decision problem. Results illustrated for suitably designed codes show that the proposed algorithm significantly outperforms conventional iterative decoders. Finally, a generalization of the code construction, enjoying the same low-complexity decoding principle is presented and analyzed, achieving tangible coding gains at moderate error rates.

Efficient Incomplete Block Designs Through Linear Integer Programming

SYNOPTIC ABSTRACTThe purpose of this paper is to present a linear integer programming approach to construct efficient binary incomplete block designs for any given number of treatments v, number of blocks b, with common block-size k, and with a nearly balanced concurrence matrix. The proposed approach is illustrated by constructing an efficient incomplete block design. A-efficient and D-efficient incomplete block designs have been constructed and catalogued using the proposed algorithm for a restricted range of parameters 3 ⩽ v ⩽ 20, b ⩾ v, and 2 ⩽ k ⩽ min(10, v − 1), with vb⩽1, 000. An R package is developed to implement the proposed approach.

A novel secure block data-hiding algorithm using cellular automata to enhance the performance of JPEG steganography

The computational complexity of matrix embedding (ME)-based steganography is high due to the use of the Hamming parity check matrix and matrix multiplication. Furthermore, with only one embedding change solution, ME cannot minimize embedding distortions when applied to joint photographic experts group (JPEG) steganography. In this paper, we propose a novel block data-hiding (BDH) algorithm to improve the performance of JPEG steganography. BDH allows a byte of data to be hidden in a binary block by modifying a maximum of two bits of the binary block must be changed. Moreover, BDH can be applied to the new channel selection rule for JPEG steganography with more available embedding solutions and less computational complexity than modified matrix embedding (MME). In addition, to increase the security of hidden data against extraction attacks, the secret message is encrypted by a cipher based on cellular automata (CA). The bitwise XOR operator is employed in the encryption process to maintain speed and security when a non-repeating key stream is used. The experimental results indicate that the proposed approach has a high anti-detection property against ensemble classifiers (universal steganalyzers), high security against recovery attacks, and good perceptual quality.

Optimal cross-over designs for total effects under a model with self and mixed carryover effects

We consider cross-over designs for a model that includes specific carryover effects when a treatment is preceded by itself. When the parameters of interest are total effects, i.e. the sum of direct effects of treatment and self-carryover effects, we show that optimal designs are a compromise between designs balanced on subjects such as balanced binary block designs and designs with subjects having a single treatment. We also propose universally optimal designs with a reduced number of subjects.

Decoding Binary Linear Block Codes Using Local Search

This paper presents a novel iterative hard decision decoding algorithm for binary linear block codes over a binary symmetric channel (BSC). The problem is formulated as a 0-1 integer programming problem which is known to be NP-hard. When the crossover probability c of the channel is known, the solution space of the decoding problem can be decreased to a sphere whose radius is related to c. Using the penalty function method, the problem is reformulated on this reduced solution space. Then an iterative multi-flip local search algorithm is designed to find the global solution of this decoding problem. For a code with minimum distance d, when the radius of the sphere is not greater than d-1/2, this algorithm has the maximum likelihood (ML) certificate property, i.e., if the decoder outputs a codeword, it is guaranteed to be the ML codeword. Compared to the probabilistic suboptimal iterative belief propagation (BP) decoder, this approach has lower complexity and better performance. Numerical results show that in terms of speed and performance the proposed decoding method outperforms BP decoding in the error floor region.

Various Phase Behaviors of Weakly Interacting Binary Block Copolymer Blends

We investigated the phase behaviors of block copolymer (BCP) blends composed of the weakly interacting (with no specific interaction) polystyrene-b-poly(n-butyl methacrylate) (PS-b-PnBMA) and polystyrene-b-poly(n-hexyl methacrylate) (PS-b-PnHMA), using small-angle neutron scattering (SANS), small-angle X-ray scattering (SAXS), and depolarized light scattering (DPLS). A miscible phase between the PnBMA and PnHMA blocks in the BCP blends allows the various composition-dependent phase behaviors, which display a lower disorder-to-order transition (LDOT) to an order-to-disorder transition (ODT) on heating as the blend composition varies from PS-b-PnBMA to PS-b-PnHMA. In between these two extremes, intriguingly, the miscible PS-b-PnBMA/PS-b-PnHMA blends display a closed-loop phase transition consisting of a LDOT and an upper order-to-disorder transition (UODT).

Linear binary block code with prescribed minimum and maximum weight

A strategy is described which allowed new optimal binary linear codes to be constructed. Using the method, among other codes a new [48, 16, 16] optimal linear binary block code was constructed. The construction of this new code settles a conjecture mentioned in the paper by Janosov and colleagues (see appropriate Reference in Letter) where the authors found a new optimal [47, 15, 16]-code, whose parameters are also relevant to the present author's new method.

Spectral Distribution of Product of Pseudorandom Matrices Formed From Binary Block Codes

Let A ∈ {-1,1}Na ×n and B ∈ {-1,1}Nb ×n be two matrices whose rows are drawn i.i.d. from the codewords of the binary codes Ca and Cb of length n and dual distances d'a and d'b, respectively, under the mapping 0 → 1 and 1 → -1. It is proven that as n → ∞ with ya:=n/Na ∈ (0,∞) and yb:=n/Nb ∈ (0, ∞) fixed, the empirical spectral distribution of the matrix A B*/√{Na Nb} resembles a universal distribution (closely related to the distribution function of the free multiplicative convolution of two members of the Marchenko-Pastur family of densities) in the sense of the Levy distance, if the asymptotic dual distances of the underlying binary codes are large enough. Moreover, an explicit upper bound on the Levy distance of the two distributions in terms of ya, yb, d'a, and d'b is given. Under mild conditions, the upper bound is strengthened to the Kolmogorov distance of the underlying distributions. Numerical studies on the empirical spectral distribution of the product of random matrices from BCH and Gold codes are provided, which verify the validity of this result.

Reaction-Induced Microphase Separation in Epoxy Thermosets Containing Block Copolymers Composed of Polystyrene and Poly(ε-caprolactone): Influence of Copolymer Architectures on Formation of Nanophases

We report an investigation of the influence of block copolymer architectures on formation of nanophases in epoxy thermosets via reaction-induced microphase separation approach. Toward this end, three binary block copolymers composed of polystyrene (PS) and poly(ε-caprolactone) (PCL) were synthesized via the combination of ring-opening polymerization (ROP) and atomic transfer radical polymerization (ATRP). These block copolymers possess PS-b-PCL diblock, PS-b-PCL-b-PS triblock, and PCL-b-PS-b-PCL triblock architectures; they were carefully controlled to have the identical composition and overall molecular weights. It was found that the block copolymers with different architectures in epoxy thermosets displayed quite different reaction-induced microphase separation behavior as evidenced with the results of atomic force microscopy (AFM), small-angle X-ray scattering (SAXS), and dynamic mechanical thermal analysis (DMTA). The morphological transition from spherical to cylindrical to lamellar nanophases occurred with increasing the content of the block copolymer in the thermosets containing PS-b-PCL diblock copolymer. In the thermosets containing PS-b-PCL-b-PS triblock copolymer, unilamellar and multilamellar nanophases were formed depending on the content of the triblock copolymer. In contrast, the macroscopic phase separation occurred in the thermosets containing PCL-b-PS-b-PCL triblock copolymer. The behavior of nanophases in these thermosetting blends have been accounted for the demixing behavior of the miscible blocks (viz. PCL) during the reaction-induced microphase separation and the influence of copolymer architectures on the morphologies of PS microdomains.

Ordered statistics-based list decoding techniques for linear binary block codes

The ordered statistics-based list decoding techniques for linear binary block codes of small to medium block length are investigated. The construction of a list of the test error patterns is considered. The original ordered-statistics decoding (OSD) is generalized by assuming segmentation of the most reliable independent positions (MRIPs) of the received bits. The segmentation is shown to overcome several drawbacks of the original OSD. The complexity of the ordered statistics-based decoding is further reduced by assuming a partial ordering of the received bits in order to avoid the complex Gauss elimination. The probability of the test error patterns in the decoding list is derived. The bit error rate performance and the decoding complexity trade-off of the proposed decoding algorithms is studied by computer simulations. Numerical examples show that, in some cases, the proposed decoding schemes are superior to the original OSD in terms of both the bit error rate performance as well as the decoding complexity.

Design of an Efficient Maximum Likelihood Soft Decoder for Systematic Short Block Codes

Maximum likelihood soft-decision decoding of linear block codes is addressed in this correspondence. A novel algorithm based on Chase-2 algorithm for the decoding of systematic binary block codes is detailed. A double re-encoding technique in place of the classical algebraic decoding for the computation of the candidate codeword list is the major innovation of the proposed algorithm. This approach has been successfully applied to systematic block codes that have a code rate equal to 1/2 and a parity check matrix composed of an invertible submatrix for the redundancy part. Simulation results show performance close to the optimum maximum likelihood decoding for an excellent tradeoff between BER performance and computational complexity. Then, the challenging issue of designing a decoder for a specific family of short binary block codes, called Cortex codes is also described. Three soft decoders for Cortex codes with lengths equal to 32, 64, and 128 and a code rate equal to 1/2 have been designed. Then, all the decoders were successively implemented onto an field-programmable gate array (FPGA) device. To our knowledge, they are the first efficient digital implementations of Cortex codes.

An Efficient Encoding Algorithm for (n, k) Binary Cyclic Codes

In forward error correction (FEC) systems, basically two mechanisms namely block coding and convolutional coding are used for error-control coding. The error-control coding processes involve encoding and decoding information symbols to get rid of errors produced by noise in communication channels. In a binary block encoding technique, message words are arranged in blocks of k bits which are converted into code words of n bits, n> k , by adding redundancy bits. Encoding is a compulsory part of error correcting codes and without knowledge of encoding structure the decoding of code words is impossible. In this paper a very simple and most effective technique for systematic encoding of linear binary cyclic codes is used which improves the encoding speed by reducing the computational complexity. In addition to encoding speed, the encoding can be done by hand using XOR (modulo-2) operations without involving computers after generating an encoding table for the code.

Complexity Reduction of Ordered Statistics Decoding Using Side Information

In this letter, the complexity of the ordered statistics decoding of linear binary block codes is reduced assuming that partial knowledge about the transmitted codeword is available at the decoder. Such side information is provided to the decoder at the receiver from the encoder at the transmitter over a highly reliable low-rate channel. Side information is exploited at the decoder to significantly reduce the number of test codewords that have to be examined during the decoding without sacrificing the error rate performance of the decoder. Side information is represented either by the single parity checks of non-overlapping codeword segments, or by the Hamming weight of the codeword or its part. The proposed method can be readily integrated with other list decoding techniques. Finally, implementation of the proposed complexity reducing scheme in practical systems is also discussed.

Reconstruction of a Non-binary Block Code from an Intercepted Sequence with Application to Reed-Solomon Codes

In this paper, a method is proposed for reconstruction of the parameters of a non-binary block encoder using an intercepted sequence of noisy coded data. The proposed method is a generalization of the Barbier's method for the reconstruction of binary block codes to the more problematic case of non-binary codes. It has been shown mathematically that considering some revisions in definitions, such a generalization is possible. The proposed method is able to estimate the code parameters such as the code length, the code dimension, number of bits per symbol, and the dual-code subspace, and also to synchronize the sequence. Since the Reed-Solomon code is the most important type of non-binary block codes, an additional method is proposed to reconstruct the generator polynomial in the case of Reed-Solomon codes. The proposed method is evaluated via computer simulations which verify its strength and effectiveness.

Efficient circular neighbour designs for spatial interference model

We consider circular block designs for field-trials when there are two-sided spatial interference between neighbouring plots of the same blocks. The parameter of interest is total effects that is the sum of direct effect of treatment and neighbour effects, which correspond to the use of a single treatment in the whole field. We determine universally optimal approximate designs. When the number of blocks may be large, we propose efficient exact designs generated by a single sequence of treatment. We also give efficiency factors of the usual binary block neighbour balanced designs which can be used when the number of blocks is small.

Optimal and suboptimal structured algorithms of binary linear block codes

Optimal and suboptimal structured algorithms of binary linear block codes

Supramolecular Assembly of Binary Block Copolymers of PEO-b-PMAA and PEO-b-PMAZO

Amphiphilic block copolymers have attracted increasing attention due to their potential applications in controlled release and biotechnology. The self-assembled aggregates consisit of a hydrophobic core and hydrophilic shell to produce a vehicle suitable for delivering hydrophobic drugs. In addition, stimuli-responsive polymers can be triggered by external factors and give rise to the corresponding physical and/or chemical changes. So far reports concerning the supramolecular assembly between two or more kinds of block copolymers are limited. In this work, supramolecular assembly of binary block copolymers of PEO-b-PMAA and PEO-b-PMAZO in the selective solvent was investigated.

High-Speed Reconfigurable Parallel System to Design Good Error Correcting Codes in Communications

This paper presents a circuit that aids to accelerate the design of good error correcting codes in communications, where this design is a large optimization problem. The binary linear block codes detects and/or corrects the errors occurred during the data transmission. The problem to find a code that corrects a maximum number of errors is an optimization problem usually tackled by means of evolutionary algorithms and massive parallel computations. The circuit has been implemented on FPGA devices due to the easiness of the reconfigurable hardware to support real parallelism. The obtained results show that parallelizing the arithmetic operations involved in the fitness function improves the performance of a custom hardware solution in contrast to a software solution running on CPUs.