1,188 research outputs found
Computational Complexity Optimization on H.264 Scalable/Multiview Video Coding
The H.264/MPEG-4 Advanced Video Coding (AVC) standard is a high efficiency and flexible video coding standard compared to previous standards. The high efficiency is achieved by utilizing a comprehensive full search motion estimation method. Although the H.264 standard improves the visual quality at low bitrates, it enormously increases the computational complexity. The research described in this thesis focuses on optimization of the computational complexity on H.264 scalable and multiview video coding.
Nowadays, video application areas range from multimedia messaging and mobile to high definition television, and they use different type of transmission systems. The Scalable Video Coding (SVC) extension of the H.264/AVC standard is able to scale the video stream in order to adapt to a variety of devices with different capabilities. Furthermore, a rate control scheme is utilized to improve the visual quality under the constraints of capability and channel bandwidth. However, the computational complexity is increased. A simplified rate control scheme is proposed to reduce the computational complexity. In the proposed scheme, the quantisation parameter can be computed directly instead of using the exhaustive Rate-Quantization model. The linear Mean Absolute Distortion (MAD) prediction model is used to predict the scene change, and the quantisation parameter will be increased directly by a threshold when the scene changes abruptly; otherwise, the comprehensive Rate-Quantisation model will be used. Results show that the optimized rate control scheme is efficient on time saving.
Multiview Video Coding (MVC) is efficient on reducing the huge amount of data in multiple-view video coding. The inter-view reference frames from the adjacent views are exploited for prediction in addition to the temporal prediction. However, due to the increase in the number of reference frames, the computational complexity is also increased. In order to manage the reference frame efficiently, a phase correlation algorithm is utilized to remove the inefficient inter-view reference frame from the reference list. The dependency between the inter-view reference frame and current frame is decided based on the phase correlation coefficients. If the inter-view reference frame is highly related to the current frame, it is still enabled in the reference list; otherwise, it will be disabled. The experimental results show that the proposed scheme is efficient on time saving and without loss in visual quality and increase in bitrate.
The proposed optimization algorithms are efficient in reducing the computational complexity on H.264/AVC extension. The low computational complexity algorithm is useful in the design of future video coding standards, especially on low power handheld devices
Motion Analysis of Live Objects by Super-Resolution Fluorescence Microscopy
Motion analysis plays an important role in studing activities or behaviors of live objects in medicine, biotechnology, chemistry, physics, spectroscopy, nanotechnology, enzymology, and biological engineering. This paper briefly reviews the developments in this area mostly in the recent three years, especially for cellular analysis in fluorescence microscopy. The topic has received much attention with the increasing demands in biomedical applications. The tasks of motion analysis include detection and tracking of objects, as well as analysis of motion behavior, living activity, events, motion statistics, and so forth. In the last decades, hundreds of papers have been published in this research topic. They cover a wide area, such as investigation of cell, cancer, virus, sperm, microbe, karyogram, and so forth. These contributions are summarized in this review. Developed methods and practical examples are also introduced. The review is useful to people in the related field for easy referral of the state of the art
Spatial clustering and common regulatory elements correlate with coordinated gene expression
Many cellular responses to surrounding cues require temporally concerted
transcriptional regulation of multiple genes. In prokaryotic cells, a
single-input-module motif with one transcription factor regulating multiple
target genes can generate coordinated gene expression. In eukaryotic cells,
transcriptional activity of a gene is affected by not only transcription
factors but also the epigenetic modifications and three-dimensional chromosome
structure of the gene. To examine how local gene environment and transcription
factor regulation are coupled, we performed a combined analysis of time-course
RNA-seq data of TGF-\b{eta} treated MCF10A cells and related epigenomic and
Hi-C data. Using Dynamic Regulatory Events Miner (DREM), we clustered
differentially expressed genes based on gene expression profiles and associated
transcription factors. Genes in each class have similar temporal gene
expression patterns and share common transcription factors. Next, we defined a
set of linear and radial distribution functions, as used in statistical
physics, to measure the distributions of genes within a class both spatially
and linearly along the genomic sequence. Remarkably, genes within the same
class despite sometimes being separated by tens of million bases (Mb) along
genomic sequence show a significantly higher tendency to be spatially close
despite sometimes being separated by tens of Mb along the genomic sequence than
those belonging to different classes do. Analyses extended to the process of
mouse nervous system development arrived at similar conclusions. Future studies
will be able to test whether this spatial organization of chromosomes
contributes to concerted gene expression.Comment: 30 pages, 9 figures, accepted in PLoS Computational Biolog
Charge transport and electron-hole asymmetry in low-mobility graphene/hexagonal boron nitride heterostructures
Graphene/hexagonal boron nitride (G/-BN) heterostructures offer an
excellent platform for developing nanoelectronic devices and for exploring
correlated states in graphene under modulation by a periodic superlattice
potential. Here, we report on transport measurements of nearly
-twisted G/-BN heterostructures. The heterostructures
investigated are prepared by dry transfer and thermally annealing processes and
are in the low mobility regime (approximately
at 1.9 K). The replica
Dirac spectra and Hofstadter butterfly spectra are observed on the hole
transport side, but not on the electron transport side, of the
heterostructures. We associate the observed electron-hole asymmetry to the
presences of a large difference between the opened gaps in the conduction and
valence bands and a strong enhancement in the interband contribution to the
conductivity on the electron transport side in the low-mobility G/-BN
heterostructures. We also show that the gaps opened at the central Dirac point
and the hole-branch secondary Dirac point are large, suggesting the presence of
strong graphene-substrate interaction and electron-electron interaction in our
G/-BN heterostructures. Our results provide additional helpful insight into
the transport mechanism in G/-BN heterostructures.Comment: 7 pages, 4 figure
Recent Advances in Morphological Cell Image Analysis
This paper summarizes the recent advances in image processing methods for morphological cell analysis. The topic of morphological analysis has received much attention with the increasing demands in both bioinformatics and biomedical applications. Among many factors that affect the diagnosis of a disease, morphological cell analysis and statistics have made great contributions to results and effects for a doctor. Morphological cell analysis finds the cellar shape, cellar regularity, classification, statistics, diagnosis, and so forth. In the last 20 years, about 1000 publications have reported the use of morphological cell analysis in biomedical research. Relevant solutions encompass a rather wide application area, such as cell clumps segmentation, morphological characteristics extraction, 3D reconstruction, abnormal cells identification, and statistical analysis. These reports are summarized in this paper to enable easy referral to suitable methods for practical solutions. Representative contributions and future research trends are also addressed
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