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With a similar capability of processing spikes as biological neural systems, networks of spiking neurons are expected to achieve a performance similar to that of living brains. In recent days, many great achievements have been made in spiking neuron models and its learning algorithm. We build an integrated model using spiking neural networks (SNNs), which performs phase encoding method and delay learning-based...
High Efficiency Video Coding (HEVC) is the latest video coding standard. It aims to provide significant improvement of compression performance with considerable increment of computational complexity, compared with all exiting video coding standards. In this paper, we propose an adaptive CU depth selection mechanism (ACDSM) for inter mode decision. To avoid unnecessary CU partition by rate distortion...
HEVC is the current joint video coding standardization project of ITU-T Video Coding Experts Group and Moving Picture Experts Group. It includes deblocking filter (DF) and adaptive loop filter (ALF) after the deblocking filter. To improve the accuracy, the deblocking filter is modified with the parameter information of intra coded blocks in this paper. Considering that the masking effect of human...
Due to the strong ability in combating multipath fading, OFDM has been adopted in IEEE802.11a standard and has received considerable attention. The fundamental physical layer parts of OFDM-based IEEE802.11a are modeled and simulated in this paper. Second, we discussed the bit error rate performance of BCH, cyclic and convolutional coding in AWGN channel. Moreover, the system performance of four working...
We built a Simulink PHY Layer platform of OFDM-based IEEE802.11a standard. An improved puncturing method was proposed according to the principle of Viterbi decoding, and we did some simulations and analysis of the link layer properties under different Eb/N0 based on the same parameters of the PHY Layer in IEEE802.11a. We could reach the conclusion of the improved puncturing method increases about...
Distributed video coding (DVC) is considered as one promising video coding scheme for Wireless Video Sensor Network (WVSN) due to its high compression efficiency and error resilience functionalities, as well as the low encoding complexity. This paper presents an improved DVC scheme based on the source classification in wavelet domain. In this scheme, the new side information (SI) refinement method...
Distributed video coding (DVC) is considered as one promising video coding scheme for Wireless Video Sensor Network (WVSN) due to its high compression efficiency and error resilience functionalities, as well as the low encoding complexity. In this paper, an improved DVC scheme based on checkerboard pattern splitting for Wyner-Ziv (WZ) frame is presented. In specific, the modified three-dimensional...
This paper presents an improved feedback-assisted low complexity WZVC scheme. The performance of this scheme is improved by two enhancements: an improved mode-based key frame encoding and a 3DRS-assisted (three-dimensional recursive search assisted) motion estimation algorithm for WZ encoding. Experimental results show that our coding scheme can achieve significant gain compared to state-of-the-art...
The side information (SI) generation is a key function in the Wyner-Ziv (WZ) video coding, which plays an important role in determining the performance of the codec. This paper proposes an improved SI generation scheme for wavelet transform based WZ video codec. In specific, we adopt the motion estimation with Kalman filter, by which an optimal estimation of motion vector can be achieved. Simulation...
It is well known that opportunistic relaying combats wireless fading and network coding in multicast reduces retransmission times. In this article, a network coded multicast retransmission scheme based on opportunistic relaying (NCMR-OR) is proposed, which combines the two above techniques to further improve the efficiency of wireless multi-hop multicast. The outage probability and transmission bandwidth...
Lossless coding is commonly found in binary image encoding with lower compression ratio. In this paper, image segmentation is used to classify the document image into line image regions, text image regions and halftone image regions. According to different features of each region, different encoding methods are applied to improve the image compression ratio. Adaptive arithmetic coding is used for...
Alamouti scheme provides a diversity gain no more than 2 over time-selective fading channels under the circumstances of 2??1 MIMO. A full-rate space-time code, space-time codes for time-selective fading (STC-TS), is proposed to provide more diversity gain when the channels fade fast. While the transmission lasts 2N (N>1) symbol periods, the diversity gain is almost 2N. What's more, the optimization...
Classification of network traffic is basic and essential for many network researches and managements. However, classification of network traffic using port-based and simple payload-based methods is diminished with the rapid development of peer-to-peer (P2P) application using dynamic port, disguising techniques and encryption to avoid detection. An alternative method based on statistics and machine...
H.264/AVC encoder complexity is remarkable mainly due to variable block size motion estimation (ME) and exhaustive rate distortion optimization (RDO). This makes real-time video coding very difficult. In this paper, a novel fast mode decision algorithm for P-slices is presented to reduce the computational load. Based on the temporal and spatial correlation between macroblocks, a four paths prediction...
Through experiments on combinations of coding tools included in H.264/AVC, we obtain an optimal combination of coding tools for the mobile multimedia broadcasting application. Although H.264/AVC has defined several profiles and levels for different applications, the partitions are still imprecise. The mobile communication network is usually with limited bandwidth and different kinds of fading and...
In the scalable video coding extension of H.264 standard, the concept of inter-layer prediction is adopted to reduce the redundancy between the base layers and the enhancement layers. Thus, additional coding modes should be calculated during the macroblock mode decision procedure at the enhancement layers. It increases the computational complexity and may obstruct its practical applications. A fast...
Scene changes and rapid motion may occur anywhere in a sequence. Commonly, the bit rate of these coded sequences fluctuates and the image quality suffers from severe degradation. If the scene changes and the rapid motion are taken into consideration in bit allocation scheme, the fluctuation of both bit rate and image quality will be reduced. In this work, an intra-frame rate-quantization (R-Q) model...
In this paper, we introduce a new implementation of motion-compensated temporal filter (MCTF) based video coder which utilizes rate-distortion optimal wavelet packet transform (RDWP) for some low bit rate video coding application scenarios. Although enhanced MC-EZBC video coder provides good scalability and high coding efficiency at high bit rates, reconstructed video quality will drop rapidly with...
In order to avoid the loss of spectral efficiency (throughput) caused by half-duplex mode and further improve achievable throughput performance of wireless multi-hop network, a relaying technique that utilizes two sets of relays and physical network coding over bi-directional traffic flows is introduced. We term such technique as Bi-directional Successive Relaying based on Physical Network Coding...
In this paper, a novel compression method on text image, called a gray-level reducing-based text image coding method (GRTIC), is proposed. The characteristic of text image is analyzed, and not the traditional binary mode but gray-level mode is needed in text image coder at low-resolution to recognize the characters. Furthermore, in gray-level text image coder, just a few gray levels are needed to...
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