Research has shown that information processing differences associated with autism could impact on language and literacy development. This study tested an approach to autistic cognition that suggests learning occurs vi...
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Research has shown that information processing differences associated with autism could impact on language and literacy development. This study tested an approach to autistic cognition that suggests learning occurs via prediction errors, and autistic people have very precise and inflexible predictions that result in more sensitivity to meaningless signal errors than non-autistic readers. We used this theoretical background to investigate whether differences in prediction coding influence how orthographic (Experiment 1) and semantic information (Experiment 2) is processed by autistic readers. Experiment 1 used a lexical decision task to test whether letter position information was processed less flexibly by autistic than non-autistic readers. Three types of letter strings: words, transposed letter and substituted letters nonwords were presented. Experiment 2 used a semantic relatedness task to test whether autistic readers processed words with high and low semantic diversity differently to non-autistic readers. Results showed similar transposed letter and semantic diversity effects for all readers;indicating that orthographic and semantic information are processed similarly by autistic and non-autistic readers;and therefore, differences in prediction coding were not evident for these lexical processing tasks.
Screen contents have become a popular image type driven by the growing market for transferring display screen between devices, especially mobile devices. Due to the ultra-high quality display featured in most of nowad...
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Screen contents have become a popular image type driven by the growing market for transferring display screen between devices, especially mobile devices. Due to the ultra-high quality display featured in most of nowadays mobile devices, lossless screen content coding (SCC) is usually required or preferred. Mobile devices also require ultra-low power consumption in all tasks including SCC. To address these issues, this paper proposes an ultra-low coding complexity technique based on string matching for high efficiency lossless SCC. The technique covers three major coding phases of fast searching, prediction, and entropy coding. Condensed hash table (CHT) based fast searching is proposed to speed-up reference string searching process. Coplanar prediction (CP) and predictor-dependent residual (PDR) are presented to first efficiently predict an unmatchable pixel using multiple neighboring pixels and then further reduce the entropy of prediction residuals. To achieve a good trade-off between coding complexity and efficiency, 4-bit-aligned variable length code (4bVLC) and byte-aligned multi-variable-length-code (BMVLC) are proposed to code the prediction residuals and three string matching parameters, respectively. For 184 screen content images commonly used, compared with X265 and PNG in the default configuration and lossless mode, the proposed technique achieves 35.67% less total compressed bytes with only 0.96% encoding and 1.54% decoding runtime, and 10.04% less total compressed bytes with only 6.83% encoding and 24.32% decoding runtime, respectively. The proposed technique also outperforms X265 and PNG in all other configurations. For twelve HEVC-SCC CTC images, compared with PNG in fast, default and slow configurations and X265 in ultrafast and default configurations, the proposed technique shows significant advantage with both high coding efficiency and ultra-low coding complexity.
Alpha channel is being applied in an increasing number of mobile web applications on mobile devices that require ultra-low power consumption in all cases including compute-intensive video encoding and decoding. Thus, ...
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Alpha channel is being applied in an increasing number of mobile web applications on mobile devices that require ultra-low power consumption in all cases including compute-intensive video encoding and decoding. Thus, we propose an ultra-low coding complexity and high efficiency alpha channel lossless coding approach. A novel coding framework and four new coding schemes are proposed for alpha channel coding. The framework fuses a string matching technique and a proposed prediction coding scheme named bit-depth preserving prediction (BDPP) together to reduce the correlations within and between repeated identical patterns and neighboring pixels. To achieve a good tradeoff between complexity and efficiency, either the unmatchable bytes are coded directly or the BDPP residuals of unmatchable bytes are coded by a proposed bytewise entropy coding scheme named 0.5-1-2byte-size-code. The other string matching parameters are coded by another proposed bytewise entropy coding scheme named byte-size multi-variable-length-code. To speed up the string-matching search, we apply a fast string search scheme that combines special position search and hash-based search. For the selected typical 236 alpha test images, compared with x265 in the fastest configuration and lossless mode, the proposed lossless approach achieves 14.33% less total compressed bytes with only 2.75% encoding and 1.83% decoding runtime. The proposed approach also outperforms the conventional lossless coding techniques such as LZ4HC, ZLIB, and PNG.
Due to the emergence of visual privacy issues, encrypted image processing has attracted a lot of attention. Data hiding in encrypted images (DHEI) is an effective method to embed secret data in the encrypted domain an...
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Due to the emergence of visual privacy issues, encrypted image processing has attracted a lot of attention. Data hiding in encrypted images (DHEI) is an effective method to embed secret data in the encrypted domain and protect the image privacy. However, existing methods do not allow a large amount of embedding capacity. In this letter, we propose a novel DHEI scheme utilizing prediction coding based on compressive sensing (CS) progressive recovery. The original image is pre-processed using CS prediction technique to create spare room, and then the image is encrypted and sent to the data hider. Furthermore, the data hider could embed secret data into Most Significant Bits (MSBs) of the corresponding locations. In the decoding phase, the embedded data can be extracted without any distortion and the original image could be reconstructed. Experimental results demonstrate that our scheme can achieve a higher embedding capacity than other state-of-the-art schemes while keeping a considerable recovered image quality.
The next generations of cellular wireless systems promise an improved user experience with respect to the throughput, reliability, latency, and connectivity. To this end, multiple-input multiple-output (MIMO) and mass...
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ISBN:
(数字)9781728138930
ISBN:
(纸本)9781728138930
The next generations of cellular wireless systems promise an improved user experience with respect to the throughput, reliability, latency, and connectivity. To this end, multiple-input multiple-output (MIMO) and massive MIMO systems hold enormous potential. Moreover, due to heterogeneity and densification, user and base station locations are increasingly random. Thus, in this paper, we characterize the performance of a typical downlink user within a massive MIMO Voronoi cell when the base stations employ matched filter based precoding in the downlink We consider a typical Voronoi cell where the base stations follow a Poisson point process (PPP), and also consider the users to be randomly distributed according to a PPP independent from the base stations. Furthermore, a wireless channel with log-distance path loss and Rayleigh fading is assumed. Using a novel framework to model the signal to noise ratio, the outage probability of a user is derived in closed-form while taking into account full and partial loading for the cell's base station due to the randomness of user numbers. Numerical results show that the outage probability is heavily dependent on the base station density, and that the performance decreases when the maximum number of users served by a base station increases.
An uplink hybrid nonorthogonal multiple access (h-NOMA) scheme utilizing power domain multiplexing is adopted in this paper for orthogonal frequency-division multiplexing (OFDM)-based systems. The OFDM-based NOMA syst...
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An uplink hybrid nonorthogonal multiple access (h-NOMA) scheme utilizing power domain multiplexing is adopted in this paper for orthogonal frequency-division multiplexing (OFDM)-based systems. The OFDM-based NOMA systems can achieve high spectral efficiency with resilience to wireless multipath fading. The h-NOMA maintains a low interference level per resource block or low complexity of multiuser detection (MUD) implementation at the receiver and also achieves consistent fairness performance by restricting the maximum number of users per resource block. An improved user clustering algorithm for OFDM-based h-NOMA system under the assumption of user's distinct data rate requirement is presented here. The proposed algorithm takes into consideration both the channel gain of all activated users and the different data rate requirements of weak channel gain users. High peak-to-average power ratio (PAPR) and performance degradation due to strict frequency synchronization requirements are the main drawbacks of such an OFDM-based uplink h-NOMA system. High PAPR of multicarrier NOMA is addressed here with precoding techniques. An enhanced minimum mean square error (MMSE) receiver performing joint equalization and carrier frequency offset (CFO) compensation using low-complexity banded-matrix implementation is proposed to cancel interference in the frequency domain. The MUD is implemented with low-complexity successive interference cancellation (SIC) using bandedmatrix approximation of the interference matrix in the presence of CFO. Moreover, the possibility of utilizing efficient trigonometric transforms to implement OFDM-based NOMA is studied with CFO and estimation errors. For OFDM-based h-NOMA system, an efficient combination of different trigonometric transform configurations to constitute the multicarrier basis for OFDM with a suitable precoding strategy for PAPR reduction is studied.
Human brain has been used as an inspiration for building autonomous agents, but it is not obvious what level of computational description of the brain one should use. This has led to overly opinionated symbolic approa...
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ISBN:
(纸本)9781713832621
Human brain has been used as an inspiration for building autonomous agents, but it is not obvious what level of computational description of the brain one should use. This has led to overly opinionated symbolic approaches and overly unstructured connectionist approaches. We propose that using homeostasis as the computational description provides a good compromise. Similar to how physiological homeostasis is the regulation of certain homeostatic variables, cognition can be interpreted as the regulation of certain 'cognitive homeostatic variables'. We present an outline of a Cognitive Homeostatic Agent, built as a hierarchy of physiological and cognitive homeostatic subsystems and describe structures and processes to guide future exploration. We expect this to be a fruitful line of investigation towards building sophisticated artificial agents that can act flexibly in complex environments, and produce behaviors indicating planning, thinking and feelings.
We suggest that music perception is an active act of listening, providing an irresistible epistemic offering. When listening to music we constantly generate plausible hypotheses about what could happen next, while act...
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We suggest that music perception is an active act of listening, providing an irresistible epistemic offering. When listening to music we constantly generate plausible hypotheses about what could happen next, while actively attending to music resolves the ensuing uncertainty. Within the predictive coding framework, we present a novel formulation of precision filtering and attentional selection, which explains why some lower-level auditory, and even higher-level music-syntactic processes elicited by irregular events are relatively exempt from top-down predictive processes. We review findings providing unique evidence for the attentional selection of salient auditory features. This formulation suggests that 'listening' is a more active process than traditionally conceived in models of perception.
HEVC is the latest block-based video compression standard, outperforming H.264/AVC by 50% bitrate savings for the same perceptual quality. An HEVC encoder provides Rate-Distortion optimization coding tools for block-w...
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ISBN:
(纸本)9781538646595
HEVC is the latest block-based video compression standard, outperforming H.264/AVC by 50% bitrate savings for the same perceptual quality. An HEVC encoder provides Rate-Distortion optimization coding tools for block-wise compression. Because of complexity limitations, Rate-Distortion Optimization (RDO) is usually performed independently for each block, assuming coding efficiency losses to be negligible. In this paper, we propose an acceleration solution for the Intra coding scheme named Dual-JRDO, which takes advantage of Inter-Block dependencies related to both predictive coding and CABAC. The Dual-JRDO improves Intra coding efficiency at the expense of higher computational complexity. The acceleration of the Dual-JRDO scheme includes adaptive use of the Dual-JRDO model based on source analysis, short-listing and early decisions strategies. The proposed Fast Dual-JRDO reduces the original model complexity by 89.54%, while providing tractable computation for average R-D gains of -0.45% (up to -0.82%) in the HM16.12 reference software model.
Millimeter wave (mmWave) communication is a promising solution for coping with the ever-increasing mobile data traffic because of its large bandwidth. To enable a sufficient link margin, a large antenna array employin...
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ISBN:
(纸本)9781538681107
Millimeter wave (mmWave) communication is a promising solution for coping with the ever-increasing mobile data traffic because of its large bandwidth. To enable a sufficient link margin, a large antenna array employing directional beamforming, which is enabled by the availability of channel state information at the transmitter (CSIT), is required. However, CSIT acquisition for mmWave channels introduces a huge feedback overhead due to the typically large number of transmit and receive antennas. Leveraging properties of mmWave channels, this paper proposes a precoding strategy which enables a flexible adjustment of the feedback overhead. In particular, the optimal unconstrained precoder is approximated by selecting a variable number of elements from a basis that is constructed as a function of the transmitter array response, where the number of selected basis elements can be chosen according to the feedback constraint. Simulation results show that the proposed precoding scheme can provide a near-optimal solution if a higher feedback overhead can be afforded. For a low overhead, it can still provide a good approximation of the optimal precoder.
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