Block Partitioning Research Articles

Efficient haplotype block partitioning and tag SNP selection algorithms under various constraints.

Patterns of linkage disequilibrium plays a central role in genome-wide association studies aimed at identifying genetic variation responsible for common human diseases. These patterns in human chromosomes show a block-like structure, and regions of high linkage disequilibrium are called haplotype blocks. A small subset of SNPs, called tag SNPs, is sufficient to capture the haplotype patterns in each haplotype block. Previously developed algorithms completely partition a haplotype sample into blocks while attempting to minimize the number of tag SNPs. However, when resource limitations prevent genotyping all the tag SNPs, it is desirable to restrict their number. We propose two dynamic programming algorithms, incorporating many diversity evaluation functions, for haplotype block partitioning using a limited number of tag SNPs. We use the proposed algorithms to partition the chromosome 21 haplotype data. When the sample is fully partitioned into blocks by our algorithms, the 2,266 blocks and 3,260 tag SNPs are fewer than those identified by previous studies. We also demonstrate that our algorithms find the optimal solution by exploiting the nonmonotonic property of a common haplotype-evaluation function.

1-2 HEVCのブロック分割構造および変換•量子化

1-2 HEVCのブロック分割構造および変換•量子化

Block Partitioning Structure in the HEVC Standard

High Efficiency Video Coding (HEVC) is the latest joint standardization effort of ITU-T WP 3/16 and ISO/IEC JTC 1/SC 29/WG 11. The resultant standard will be published as twin text by ITU-T and ISO/IEC; in the latter case, it will also be known as MPEG-H Part 2. This paper describes the block partitioning structure of the draft HEVC standard and presents the results of an analysis of coding efficiency and complexity. Of the many new technical aspects of HEVC, the block partitioning structure has been identified as representing one of the most significant changes relative to previous video coding standards. In contrast to the fixed size 16 × 16 macroblock structure of H.264/AVC, HEVC defines three different units according to their functionalities. The coding unit defines a region sharing the same prediction mode, e.g., intra and inter, and it is represented by the leaf node of a quadtree structure. The prediction unit defines a region sharing the same prediction information. The transform unit, specified by another quadtree, defines a region sharing the same transformation. This paper introduces technical details of the block partitioning structure of HEVC with an emphasis on the method of designing a consistent framework by combining the three different units together. Experimental results are provided to justify the role of each component of the block partitioning structure and a comparison with the H.264/AVC design is performed.

Block Merging for Quadtree-Based Partitioning in HEVC

The joint development of the upcoming High Efficiency Video Coding (HEVC) standard by ITU-T Video Coding Experts Group and ISO/IEC Moving Picture Experts Group marks a new step in video compression capability. In technical terms, HEVC is a hybrid video-coding approach using quadtree-based block partitioning together with motion-compensated prediction. Even though a high degree of adaptability is achieved by quadtree-based block partitioning, this approach has certain intrinsic drawbacks, which may result in redundant sets of motion parameters being transmitted. Previous work has shown that those redundancies can effectively be removed by merging the leafs of a particular quadtree structure. Following this concept, a block merging algorithm for HEVC is now proposed. This algorithm generates a single motion parameter set for a whole region of contiguous motion-compensated blocks. In this paper, we describe the various components of the proposed block merging algorithm and, using experimental evidence, demonstrate their benefits in terms of coding efficiency.

Local design of the hot-zone in an industrial seeded directional solidification furnace for quasi-single crystalline silicon ingots

To preserve the seed crystal in the melting process and improve the thermal field in the hot-zone during the solidification process aiding the formation of a quasi-single crystalline silicon ingot, an insulation partition block was designed for use in the hot-zone of an industrial seeded directional solidification furnace. A global model taking into account thermal conduction, thermal radiation, melt convection and argon flow was established to investigate the effects of the insulation configuration design on the thermal field, solidification interface shape, melt convection, argon recirculation and power consumption. In addition to comparing insulation configuration designs with and without the partition block, we carried out a comprehensive parameter study of the local design of the hot-zone, including the position, the width and the thickness of the insulation partition block. The results show that a suitable temperature gradient and a flat or slightly convex interface during seed preservation and bulk crystal growth can be achieved to maintain the quasi-single crystal structure all the way to the top of the silicon ingot. Furthermore, the argon recirculation and energy consumption can be reduced and the melt flow motion can be controlled by good insulation partition block design.

Properties of partition wall blocks prepared with fresh concrete wastes

The research was conducted to explore the feasible use of fresh concrete waste (FCW) for the manufacturing of partition wall blocks. The FCW sourced from a ready mix concrete plant was crushed into the size of fine aggregate (<5mm), and used to replace natural sand at the proportions of 0%, 25%, 50%, 75% and 100% by weight with an aggregate/cement ratio of 12, for producing partition blocks. The properties of the blocks, such as density, water absorption, compressive and transverse strengths, and drying shrinkage as well as the loss of strength, mass and ultrasonic pulse velocity after exposure to elevated temperatures (300°C, 500°C and 800°C) were determined. The results indicate that as FCW content increased in the blocks, the water absorption increased and density decreased due to the high porosity of FCW. But the incorporation of FCW aggregates improved the mechanical properties (compressive strength and transverse strength) of the partition blocks. However it weakened the fire endurance of the blocks. The results of the study have demonstrated that it is feasible to utilize the FCW in the production of non load-bearing concrete products, such as partition blocks.

A double mapping framework for extraction of shape-invariant features based on multi-scale partitions with AdaBoost for video smoke detection

Traditional methods for video smoke detection can easily achieve very low training errors but their generalization performances are not good due to arbitrary shapes of smoke, intra-class variations, occlusions and clutters. To overcome these problems, a double mapping framework is proposed to extract partition based features with AdaBoost. The first mapping is from an original image to block features. A feature vector is presented by concatenating histograms of edge orientation, edge magnitude and Local Binary Pattern (LBP) bit, and densities of edge magnitude, LBP bit, color intensity and saturation. Each component of the feature vector produces a feature image. To obtain shape-invariant features, a detection window is partitioned into a set of small blocks called a partition, and many multi-scale partitions are generated by changing block sizes and partition schemes. The sum of each feature image within each block of each partition is computed to generate block features. The second mapping is from the block features to statistical features. The statistical features of the block features, such as, mean, variance, skewness, kurtosis and Hu moments, are computed on all partitions to form a feature pool. AdaBoost is used to select discriminative shape-invariant features from the feature pool. Experiments show that the proposed method has better generalization performance and less insensitivity to geometry transform than traditional methods.

Influence of an insulation partition on a seeded directional solidification process for quasi-single crystalline silicon ingot for high-efficiency solar cells

An insulation partition was designed in a seeded directional solidification (DS) furnace of industrial-size to produce quasi-single crystalline silicon ingot for solar cells of high efficiency. We used a transient global model to study the effects of the insulation partition block on the temperature and thermal stress fields in the solidified silicon ingot during the solidification process. We validated the transient global model by comparing the calculations with the experimental measurements. Simulation results show that an insulation partition block can significantly reduce the total heating power consumption and influence the temperature and velocity fields in the silicon melt. We also found that the melt-crystal interface (m–c interface) shape changes from concave to convex to the melt with a larger crystal growth rate with an insulation partition, while it always remains flat with a smaller crystal growth rate without a partition block. The axial temperature gradient and thermal stress in the grown silicon crystal increased with a partition block. The solar cells from the grown quasi-single crystalline silicon ingot exhibited higher short-circuit current (Isc) and open-circuit voltage (Voc). The average conversion efficiency of solar cells is increased to 17.8% and about 1.2% more than that based on mc-Si ingot from the conventional furnace.

Framework of a representation model for modular product development

Partitioning, development, fabrication, and management of construction blocks of modular products still heavily rely on manual labor of sophisticated designers because existing representation models seldom have automatic capability of product data processing for modular product development. To cope with this challenge, a framework for building an efficient representation model for modular product development has been developed. First, the framework redefines some very important concepts in order to make them clear and accurate. Second, the framework proposes a generic structure for modular products, which comes from the analysis and synthesis of real cases of modular product development in industry. Third, concept formalization is brought forward to facilitate manufacturers to establish responding ontology while the development process for modular product development ontology is provided as a simple reference for manufacturers to build their own modular product development ontology. Last, the analysis shows that the proposed approach is feasible, and may assist manufacturers to establish modular product development ontology for automation in modular product development.

Compositions of n as alternating sequences of weakly increasing and strictly decreasing partitions

Abstract Compositions and partitions of positive integers are often studied in separate frameworks where partitions are given by q-series generating functions and compositions exhibiting specific patterns are designated by generating functions for these patterns. Here, we view compositions as alternating sequences of weakly increasing and strictly decreasing partitions (i.e. alternating blocks). We obtain generating functions for the number of such partitions in terms of the size of the composition, the number of parts and the total number of “valleys” and “peaks”. From this, we find the total number of “peaks” and “valleys” in the composition of n which have the mentioned pattern. We also obtain the generating function for compositions which split into just two partition blocks. Finally, we obtain the two generating functions for compositions of n that start either with a weakly increasing partition or a strictly decreasing partition.

Video coding using geometry based block partitioning and reordering discrete cosine transform

Geometry based block partitioning (GBP) has been shown to achieve better performance than the tree structure based block partitioning (TSBP) of H.264. However, the residual blocks of GBP mode after motion compensation still present some non-vertical/non-horizontal orientations, and the conventional discrete cosine transform (DCT) may generate many high-frequency coefficients. To solve this problem, in this paper we propose a video coding approach by using GBP and reordering DCT (RDCT) techniques. In the proposed approach, GBP is first applied to partition the macroblocks. Then, before performing DCT, a reordering operation is used to adjust the pixel positions of the residual macroblocks based on the partition information. In this way, the partition information of GBP can be used to represent the reordering information of RDCT, and the bitrate can be reduced. Experimental results show that, compared to H.264/AVC, the proposed method achieves on average 6.38% and 5.69% bitrate reductions at low and high bitrates, respectively.

Low Power H.264 Video Compression Achitecture for Mobile Communication

This paper presents a method to reduce the computation and memory access for variable block size motion estimation (ME) using pixel truncation. Previous work has focused on implementing pixel truncation using a fixed-block size(16×16 pixels) ME. However, pixel truncation fails to give satisfactory results for smaller block partitions. In this paper, we analyze the effect of truncating pixels for smaller block partitions and propose a method to improve the frame prediction. Our method is able to reduce the total computation and memory access compared to conventional full-search method without significantly degrading picture quality. With unique data arrangement, the proposed architectures are able to saveup to 53% energy compared to the conventional full-search architecture. This makes such architectures attractive for H.264application in future mobile devices. Keywords- Low-power design, motion estimation (ME), video coding, VLSI architecture.

A High-Capacity Lossless Data Hiding Scheme for Binary Images

Many previous binary image lossless data hiding schemes often cause serious perceptible distortion and have poor visual quality of stego-images. To obtain better invisibility and higher hiding capacity, a novel reversible data hiding scheme for binary images is proposed by combining pattern substitution and human visual perception. Firstly, an improved binary image boundary detection method is presented by avoiding successive boundary pixel flipping. Secondly, secret messages are embedded into binary image boundaries by employing interlaced block partition. Finally, to achieve lossless recovery of original binary image, the side-information is lossless compressed by using the Golomb Code and the occurrence frequency of each pattern. Extensive experiments show that the proposed scheme is effective, and obtain at least 3.6 dB higher PSNR values of stego-image and 92.5% higher embedding capacity compared with Ho et al’s method.

Block-based Bayesian epistasis association mapping with application to WTCCC type 1 diabetes data

Interactions among multiple genes across the genome may contribute to the risks of many complex human diseases. Whole-genome single nucleotide polymorphisms (SNPs) data collected for many thousands of SNP markers from thousands of individuals under the case-control design promise to shed light on our understanding of such interactions. However, nearby SNPs are highly correlated due to linkage disequilibrium (LD) and the number of possible interactions is too large for exhaustive evaluation. We propose a novel Bayesian method for simultaneously partitioning SNPs into LD-blocks and selecting SNPs within blocks that are associated with the disease, either individually or interactively with other SNPs. When applied to homogeneous population data, the method gives posterior probabilities for LD-block boundaries, which not only result in accurate block partitions of SNPs, but also provide measures of partition uncertainty. When applied to case-control data for association mapping, the method implicitly filters out SNP associations created merely by LD with disease loci within the same blocks. Simulation study showed that this approach is more powerful in detecting multi-locus associations than other methods we tested, including one of ours. When applied to the WTCCC type 1 diabetes data, the method identified many previously known T1D associated genes, including PTPN22, CTLA4, MHC, and IL2RA. The method also revealed some interesting two-way associations that are undetected by single SNP methods. Most of the significant associations are located within the MHC region. Our analysis showed that the MHC SNPs form long-distance joint associations over several known recombination hotspots. By controlling the haplotypes of the MHC class II region, we identified additional associations in both MHC class I (HLA-A, HLA-B) and class III regions (BAT1). We also observed significant interactions between genes PRSS16, ZNF184 in the extended MHC region and the MHC class II genes. The proposed method can be broadly applied to the classification problem with correlated discrete covariates.

Reversible Image Data Hiding Using Quad-tree Segmentation and Histogram Shifting

This paper is working towards a high capacity histogram-based reversible data hiding algorithm with a relatively lower distortion introduced after embedding the secret message. The proposed algorithm can be thought of as an improved version of the traditional histogram shifting method. To take advantage of simple local distribution of pixel intensities, the idea behind the proposed algorithm is to consider the multiple local histograms, each of which is derived from pixels in a locally contiguous sub-image area, instead of the single histogram for the whole image area. We develop a hierarchical segmentation scheme that is able to hierarchically partition the input host image into several variable-sized blocks of pixels under a maximal capacity criterion for each block partition. These partitioned blocks are organized as a tree structure for the ease of representation. The secret message and the partition tree information are then embedded in these image blocks. With the proposed segmentation scheme, the algorithm can easily find a suitable non-overlapped partition of the image to significantly increase embedding capacity. Experimental results reveal that the proposed method can indeed provide higher embedding capacity than the traditional histogram shifting method while maintaining a high visual quality that is comparable to the traditional one without spatial segmentation scheme.

Video coding using fast geometry-adaptive partitioning and an elastic motion model

Effective motion-compensated prediction is the key to high-performance video coding. To ensure continuous improvement of video coders, emerging motion-compensation technologies will need to be successfully integrated into future standards. Higher order elastic motion models and geometry-adaptive block partitioning are such advanced techniques that are good candidates for integration into future generations of video coders. However, it is vital that these techniques are additive in performance, non-interfering and maintain justifiable complexity. In this paper, we propose an efficient block-partitioning scheme that incorporates both geometry-adaptive partitioning and an elastic motion model as extensions to the standard motion estimation procedure. Our experiments suggest that geometric partitioning in combination with the use of an elastic motion model can provide enhanced performance, although the increased complexity is of some concern for real-time applications.

Video coding using arbitrarily shaped block partitions in globally optimal perspective

Algorithms using content-based patterns to segment moving regions at the macroblock (MB) level have exhibited good potential for improved coding efficiency when embedded into the H.264 standard as an extra mode. The content-based pattern generation (CPG) algorithm provides local optimal result as only one pattern can be optimally generated from a given set of moving regions. But, it failed to provide optimal results for multiple patterns from entire sets. Obviously, a global optimal solution for clustering the set and then generation of multiple patterns enhances the performance farther. But a global optimal solution is not achievable due to the non-polynomial nature of the clustering problem. In this paper, we propose a near-optimal content-based pattern generation (OCPG) algorithm which outperforms the existing approach. Coupling OCPG, generating a set of patterns after clustering the MBs into several disjoint sets, with a direct pattern selection algorithm by allowing all the MBs in multiple pattern modes outperforms the existing pattern-based coding when embedded into the H.264.

Adaptive search range adjustment scheme for fast motion estimation in AVC/H.264

AVC/H.264 supports the use of multiple reference frames (e.g., 5 frames in AVC/H.264) for motion estimation (ME), which demands a huge computational complexity in ME. We propose an adaptive search range adjustment scheme to reduce the computational complexity of ME by reducing the search range of each reference frame-from the (t-1)'th frame to the (t-5)'th frame-for each macroblock. Based on the statistical analysis that the 16×16 mode type is dominantly selected rather than the other block partition mode types, the proposed method reduces the search range of the remaining ME process in the given reference frame according to the motion vector (MV) position of the 16×16 block ME. In the case of the (t-1)'th frame, the MV position of the 8×8 block ME-in addition to that of 16×16 block ME-is also used for the search range reduction to sub-block partition mode types of the 8×8 block. The experimental results show that the proposed method reduces about 50% and 65% of the total encoding time over CIF/SIF and full HD test sequences, respectively, without any noticeable visual degradation, compared to the full search method of the AVC/H.264 encoder.

Fast Bi-Directional Prediction Selection in H.264/MPEG-4 AVC Temporal Scalable Video Coding

In this paper, we propose a fast algorithm that efficiently selects the temporal prediction type for the dyadic hierarchical-B prediction structure in the H.264/MPEG-4 temporal scalable video coding (SVC). We make use of the strong correlations in prediction type inheritance to eliminate the superfluous computations for the bi-directional (BI) prediction in the finer partitions, 16×8/8×16/8×8 , by referring to the best temporal prediction type of 16 × 16. In addition, we carefully examine the relationship in motion bit-rate costs and distortions between the BI and the uni-directional temporal prediction types. As a result, we construct a set of adaptive thresholds to remove the unnecessary BI calculations. Moreover, for the block partitions smaller than 8 × 8, either the forward prediction (FW) or the backward prediction (BW) is skipped based upon the information of their 8 × 8 partitions. Hence, the proposed schemes can efficiently reduce the extensive computational burden in calculating the BI prediction. As compared to the JSVM 9.11 software, our method saves the encoding time from 48% to 67% for a large variety of test videos over a wide range of coding bit-rates and has only a minor coding performance loss.

Spectrally Precoded OFDM and OFDMA with Cyclic Prefix and Unconstrained Guard Ratios

Spectrally precoded orthogonal frequency-division multiplexing with cyclic prefix (SP-CP-OFDM) and SP-CP-OFDM multiple access (SP-CP-OFDMA) are investigated in this paper. A general constraint on spectral precoding is developed for both SP-CP-OFDM and SP-CP-OFDMA signal formats with unconstrained guard ratios and arbitrary input data statistics to ensure very small power spectral sidelobes decaying asymptotically as f-2J-2, with J a predesigned integer-valued parameter. In the SP-CP-OFDM signaling format, new spectral precoders are devised to meet the constraint. It is shown that the proposed SP-CP-OFDM signals can provide much smaller spectral sidelobes than the previously designed SP-CP-OFDM signals with block partitioning and constrained guard ratios. In the SP-CP-OFDMA signaling format, a general procedure is proposed to facilitate the precoder design for SP-CP-OFDMA signals with arbitrary subcarrier allocation for each user and some spectral precoders are accordingly devised. It is shown that the proposed SP-CP-OFDMA signals can suppress sidelobe powers effectively and thus achieve higher spectral compactness than nonprecoded rectangularly-pulsed CP-OFDMA.