Bit-rate Coding Research Articles

Optimal inter-view rate allocation for multi-view video plus depth over MPEG-DASH using QoE measures and paired comparison

Rapid advances in compression and transmission technologies enabled multi-view video streaming over the Internet through state-of-the-art MPEG standards such as dynamic adaptive streaming over HTTP (DASH) and high-efficiency video coding. Yet, standards for subjective and objective measurement of quality of experience (QoE) are lagging in the area. The MPEG-DASH system requires constant bitrate (CBR) coding and an efficient rate control strategy in order to increase QoE. Multi-view video plus depth format is preferable due to high compression gain but quality of intermediate view is crucial, strictly depending on performance of inter/intra-view rate allocation as well as rendering algorithms. We propose to find optimal ratio for inter-view rate allocation in CBR using our previously developed objective QoE measures using depth maps and structural similarities. To assess small differences and discriminate similar quality levels, a new subjective assessment methodology is also proposed as a multiple stimuli plus simultaneous presentation for paired comparison. The results show that the unequal rate allocation is superior to the equal rate allocation in terms of objective QoE as 0.012–0.04 (which translates into a bit rate saving of 15–24%) and subjective QoE as 0.3–0.5. Furthermore, a very high correlation is achieved between the new QoE measures and paired comparison results.

Stochastic Bit-Wise Iterative Decoding of Polar Codes

Polar codes have received recent attention due to their potential to be applied in advanced wireless communication protocols such as the fifth generation mobile communication system (5G). Among the existing decoding algorithms, Belief Propagation (BP) exhibits high-throughput, low-latency, and soft output with a high hardware cost. Stochastic computing, as a form of approximate computing, provides a potential low-cost implementation solution for the BP algorithm. However, existing stochastic BP decoders suffer from a relatively long decoding latency resulting in low hardware efficiency. In this paper, a novel bit-wise iterative stochastic decoding architecture for the BP algorithm is proposed to improve the throughput and hardware efficiency. By utilizing the frozen bits of polar codes and stochastic computing, multiple novel optimization methods are presented to further speed up convergence and increase the hardware efficiency.

A High Throughput Implementation of QC-LDPC Codes for 5G NR

Quasi-cyclic low-density parity-check (QC-LDPC) codes are the choice for data channels in the fifth generation (5G) new radio (NR). At the transmitter side, code bits from the QC-LDPC encoder are delivered to the rate matcher. The task of the rate matcher is to select an appropriate number of code bits via puncturing and/or repetition. Code bits that are not selected do not need to be encoded. At the receiver side, the de-rate matcher combines code bits of different transmission attempts and sends them to the QC-LDPC decoder. The output of the QC-LDPC decoder only needs to include necessary systematic bits. Unnecessary systematic bits and parity bits can be completely removed from the decoding process. Taking these considerations into account, a smaller sub-base matrix instead of a full-base matrix can be used in the encoding and decoding process. In this paper, we propose an efficient implementation of QC-LDPC codes for 5G NR. The full-base matrix is pruned before being used. Compared to the traditional schemes, the proposed scheme improves the throughput of QC-LDPC codes in 5G NR.

Improving the Signal-to-Noise Ratio of Time Domain Fiber Bragg Grating Sensor Based on Hybrid Simplex and Golay Coding Technique

We report on the experimental results of the combination of unique auto-correlation properties of Golay complementary code and Hadamard matrix properties of standard simplex code. The combination of the two coding techniques results in improvement of the signal-to-noise ratio (SNR) of time domain multiplexed fiber Bragg grating (TDM-FBG) sensor for temperature measurement. Previously, we have analyzed the properties of both coding techniques when deployed separately in the TDM-FBG sensor. In this case, both coding techniques result in the same amount of SNR improvement for code length longer than 31 bits. In this paper, we demonstrate the combination and simultaneous deployment of the two techniques to measure multiple FBGs under room condition (25 °C) and 50 °C temperature. The two schemes combination results in remarkable improvement of SNR and still retains the original spatial property of the decoded FBG signals, confirming the successful deployment of the hybrid codes. From the measurement of two FBG sensors located after 16 km of fiber, the combination of 31 bits of simplex- and 64 bits of Golay codes has resulted in a total of 10.5 dB improvement of SNR.

Using Codes with Summation of Weighted Bits to Organize Checking of Combinational Logical Devices

This article analyzes the peculiarities of applying weighted sum codes in tasks of building logical device check circuits for weighing of bits via random weighting coefficients, with check bits limited in number by the number of check bits of classical Berger codes. Important regularities typical of weighted sum codes are discovered. Weighted codes belong to codes that detect unidirectional errors (UED codes). The presented technique of synthesizing weighted sum codes allows creating the simplest structures of these devices based on the standard circuits of full adders and half adders of units. The main properties of weighted sum codes via error detection in information vectors and in outputs of combinational check circuits are confirmed via experiment.

A Joint Physical Layer Encryption and PAPR Reduction Scheme Based on Polar Codes and Chaotic Sequences in OFDM System

Channel coding and security are important in a communication system. The 5th generation (5G) mobile communication networks call for higher requirements of new coding technologies and encryption technologies. As an efficient coding method, polar codes have attracted more attention in recent years. Besides, the peak-to-average-power ratio (PAPR) is a major problem of the orthogonal frequency-division multiplexing (OFDM) system, which will significantly affect the performance of the OFDM system. In this paper, joint physical-layer encryption and PAPR reduction scheme is proposed, aiming to solve the PAPR problem and achieve high security of the transmission system. In this scheme, we utilize the key generation technology of wireless channels to get the initial value of chaotic sequences. Then, the chaotic sequences can be used to encrypt the information and reduce PAPR simultaneously. Moreover, we use the best information bits of polar codes to store the serial number index of chaotic sequences. The theoretic analysis and simulation results show that the proposed scheme can not only achieve high security in the physical layer but also reduce PAPR in the OFDM system without increasing system complexity and latency.

Physical Layer Encryption Algorithm Based on Polar Codes and Chaotic Sequences

Researches on 5th generation mobile communication networks (5G) are emerging to meet the demands of rapidly developing communications applications. The reliability and security of data have become key factors of its development, and thus 5G has put forward higher requirements for new coding and encryption technologies. In this paper, a physical layer encryption algorithm based on polarization codes and chaotic sequences is proposed to improve the reliability and confidentiality of transmission. In our scheme, chaotic sequences are allocated in the frozen bits of polar codes. Therefore, error correction and encryption can be performed simultaneously. Since the frozen bits are unknown to the eavesdroppers, it is difficult for them to decode the transmitted bits without the knowledge of the chaotic sequences. To further improve the security, we propose to generate the chaotic sequences by using the channel state information. Besides, the chain effects of delayed feedback are applied to increase the decrypted complexity of the eavesdroppers in this paper. Theoretic analysis and simulation results both show that the proposed algorithms can achieve high security without any error rate performance loss.

Multi-orientation and multi-scale features discriminant learning for palmprint recognition

Palmprint contains stable and effective features, especially the orientation and scale features of palm lines, and has now become an important identity recognition technique for surveillance and safety applications. Existing palmprint recognition methods using texture features can be roughly divided into two categories: coding-based and local descriptor based methods. As compared with the latter category, the former one can make full use of the palmprint specific features and acquire fast matching speed. However, most existing coding-based methods are based on the competitive coding scheme, in which the scale features of palmprint cannot be well exploited. In this work, we propose a discriminant orientation and scale features learning (DOSFL) for palmprint recognition. By introducing the idea of discriminant analysis into palmprint coding, DOSFL can extract the orientation and scale features with more favorable discriminability. Then, DOSFL utilizes four code bits to represent both the orientation and scale features of palmprint, and employs the Hamming distance for code matching. To make better use of the orientation and scale information contained in palmprint samples, we further propose a multi-orientation and multi-scale features discriminant learning (MOSDL) approach for palmprint recognition, which can fuse different orientation and scale feature information effectively in the discriminant learning process. Experimental results on two publicly available palmprint databases, including the HK PolyU database and UST palmprint image database, demonstrate that our proposed approach can achieve better recognition results than the compared methods.

A Method for Blind Identification of a Scrambler Based on Matrix Analysis

Existing methods for identifying a scrambler placed after a convolutional encoder require prior knowledge about the encoding type and a dual word of the convolutional code. To overcome these limitations, we propose here a method for blind identification of a scrambler based on matrix analysis. The rank behaviors of self-synchronously and synchronously scrambled convolutional code bit matrices are first analyzed theoretically. Based on their rank deficient characteristics, preliminary identification of the encoding type of a received sequence can then take place. After this, by using the bases in the null space of the received bit matrix, the feedback polynomial of the scrambler can be reconstructed. Furthermore, according to the rank behavior of the descrambled sequence, the type of the scrambler can be determined. This method can thus arrive at the blind identification of a scrambler without any prior knowledge.

Replicability or reproducibility? On the replication crisis in computational neuroscience and sharing only relevant detail

Replicability and reproducibility of computational models has been somewhat understudied by “the replication movement.” In this paper, we draw on methodological studies into the replicability of psychological experiments and on the mechanistic account of explanation to analyze the functions of model replications and model reproductions in computational neuroscience. We contend that model replicability, or independent researchers' ability to obtain the same output using original code and data, and model reproducibility, or independent researchers' ability to recreate a model without original code, serve different functions and fail for different reasons. This means that measures designed to improve model replicability may not enhance (and, in some cases, may actually damage) model reproducibility. We claim that although both are undesirable, low model reproducibility poses more of a threat to long-term scientific progress than low model replicability. In our opinion, low model reproducibility stems mostly from authors' omitting to provide crucial information in scientific papers and we stress that sharing all computer code and data is not a solution. Reports of computational studies should remain selective and include all and only relevant bits of code.

Adaptive Puncturing Method for Dimming in Visible Light Communication With Polar Codes

In this letter, an adaptive puncturing method on run-length limited (RLL) codes to achieve dimming control is proposed for visible light communication (VLC) with polar codes. Polar codes can be concatenated with RLL codes to provide 50% dimming in the VLC system, and the dimming value not equal to 50% can be achieved by puncturing and compensation symbols. Conventional puncturing should puncture all bits of RLL symbol, but the proposed method can adaptively puncture almost half bits of the RLL symbol, which corresponds to predetermined frozen bits of polar codes. Therefore, the proposed method can puncture fewer bits of RLL symbol and require fewer CSs in comparison to the conventional method. Simulation results show that the proposed method gives a better performance than the referenced methods.

Seu and Sefi error detection and correction on a ddr3 memory system

This paper presents an embedded design that performs a novel Single Event Upset (SEU) and Single Event Functional Interrupt (SEFI) detection and recovery technique for DDR3 Synchronous Dynamic Random-Memories (SDRAM) memories in space applications. Using a memory system composed of four devices, this SEFI recovery method allows to restore the content of one entire device using the data and the Error Correction Code (ECC) bits stored in the other three devices. This design is implemented on a Xilinx Zynq-7000 System on Chip (SoC). The SEU detection and the recovery functionality is implemented on a Xilinx Zynq as an AXI bus peripheral. This peripheral is connected with the Processing System (PS) of the device via AXI bus, where a SEFI detection algorithm is implemented in a software application that runs in the ARM Cortex-A9. The developed technique also allows to inject errors to test the whole functionality.

An Extensible Code for Correcting Multiple Cell Upset in Memory Arrays

As the microelectronics technology continuously advances to deep submicron scales, the occurrence of Multiple Cell Upset (MCU) induced by radiation in memory devices becomes more likely to happen. The implementation of a robust Error Correction Code (ECC) is a suitable solution. However, the more complex an ECC, the more delay, area usage and energy consumption. An ECC with an appropriate balance between error coverage and computational cost is essential for applications where fault tolerance is heavily needed, and the energy resources are scarce. This paper describes the conception, implementation, and evaluation of Column-Line-Code (CLC), a novel algorithm for the detection and correction of MCU in memory devices, which combines extended Hamming code and parity bits. Besides, this paper evaluates the variation of the 2D CLC schemes and proposes an additional operation to correct more MCU patterns called extended mode. We compared the implementation cost, reliability level, detection/correction rate and the mean time to failure among the CLC versions and other correction codes, proving the CLCs have high MCU correction efficacy with reduced area, power and delay costs.

On Tanner Graph Error-Detection of Some Codes due to (123)/ (132)-Avoiding Patterns of AUNU Numbers

We consider some of the codes generated due to the AUNU patterns as studied earlier by the authors (the [5 3 2] linear code, [7 4 2]-linear code and the [14 8 3] codes) . The Parity check matrices of these codes are obtained and used in constructing their Tanner graphs. A Tanner graph has n variable nodes, corresponding to the code bits of the codeword, and m check nodes that represents the parity check equations. An assignment of the code bits of a received vector is now known to be a valid code word if all the parity check equations from the Tanner graph are satisfied otherwise, an error is detected. Moreover, other code properties such as the regularity or otherwise of these codes are also determined from such Tanner graphs.

False history filtering for reducing hardware overhead of FPGA-based LZ77 compressor

Abstract Compression reduces the size of data by replacing original data with shorter bits of code or eliminating unnecessary data, thereby reducing the cost of storing and transmitting data. To reduce CPU load caused by compression, there are many cases where compression is accelerated through parallelization on additional hardware. The higher degree of parallelism leads to a higher processing bandwidth of hardware. However, it also causes a significant increase in hardware resource cost. In this paper, we propose a false history filtering technique that is used by a parallel hardware accelerator to avoid excessive hardware resource cost. This technique detects unnecessary string comparison operations that generate meaningless or unused results. The parallel hardware accelerator with false history filtering has no performance degradation even if the hardware uses less parallelized modules. Experimental results showed that the hardware LZ77 compressor with false history filtering reduces hardware usage by 5.18-18.35% without performance degradation.

Design of an Absolute Shaft Encoder Using Optically Modulated Binary Code

In order to avoid the fabrication of coding pattern over a shaft coupled disk of the binary coded absolute encoder, a new design concept has been presented in this paper. The proposed prototype can encode the binary information by optical modulation principle. Instead of lithographic fabrication, here the pattern code bits are implemented optically through a plurality of infra-red (IR) light emitting diodes (LED). Each LED transmits a bit of information as modulated optical signal and modulation is served by the principle of serial infra red control protocol. During the rotation of an object, a window position of the shaft coupled disk determines which bits’ information will be transmitted. Now, an IR detector of the receiver unit decodes this code by demodulating the transmitted signal. Finally, the absolute position of the object is evaluated from this code by searching a look-up table data. Thus, the receiver unit of the proposed encoder can sense the position of an object remotely without using any additional wireless device. Also, the sensing heads may not be damaged by the rotating disk vibration. The prototype has been tested by using De-Bruijn coding pattern and obtained promising results. Also, the proposed method is equally valid for any binary or gray pattern code.

Implementasi Pengacakan Bit Nilai Warna Spasi Pada Steganografi Di Dokumen Teks OOXML

Steganografi ada dikarenakan oleh adanya keperluan untuk menyembunyikan sebuah data di dalam data lain. Tujuan dari penelitian ini adalah untuk menemukan alternatif lain dalam melakukan steganografi melalui media berkas dokumen teks Office Open XML. Penelitian dilakukan dengan tinjauan pustaka, dan membuat komponen aplikasi. Perancangan dilakukan menggunakan flowchart. Pengujian dilakukan dengan cara membandingkan hasil, dan uji ketahanan melalui perubahan jenis berkas, dan perubahan konten, dan nama berkas. Berdasarkan hasil penelitian yang didapat, steganografi yang dilakukan dengan cara menambah pengacakan posisi bit kode warna spasi tidak memengaruhi dokumen secara signifikan secara visual. Pesan dapat tahan konversi ke jenis berkas DOC, ODT, dan PDF, 93% tahan konversi ke jenis berkas RTF, dan tidak tahan konversi ke jenis berkas TXT, dan dapat tahan perubahan konten, asalkan urutan berkas tetap ada, dan spasi tidak diganggu

Efficient Multiview Video Coding Using 3-D Coding and Saliency-Based Bit Allocation

Capturing a scene using multiple cameras from different angles is expected to provide the necessary interactivity in the 3-D space to satisfy end-users’ demands for observing objects and actions from different angles and depths. Existing multiview video coding (MVC) technologies face tradeoff among rate-distortion performance, random access frame delay, i.e., interactivity, and computational time. To address above mentioned tradeoffs, a novel cuboid MVC strategy is proposed with 3-D frame referencing structure to improve interactivity and computational time, an additional reference frame to improve rate-distortion performance for occluded areas, and visual attention-based bit allocation to provide better perceptual video quality. The experimental results reveal that the proposed scheme provides better interactivity, reduced computational time, and better perceptual quality compared to the 3D-HEVC implementation, HTM 15.0.

Code shift keying based joint radar and communications for EMCON applications

Due to the explosion in the demand for broadband wireless services by consumers, wireless network service providers require increased frequency allocations from an already crowded frequency spectrum. In an effort to satisfy the increased frequency spectrum requirements of wireless communications networks, several methods have been proposed to allow communication systems and radars to co-exist within the same bandwidth or adjacent frequency bands while minimizing or preventing mutual interference. Most methods explored in the literature focus on the use of cognitive sensing and dynamic spectrum allocation. Other proposed methods to prevent mutual interference between radar and communications systems focus on waveform design. In this manuscript, a dual function communication and radar system with EMCON applications is investigated that uses Gold or Kasami codes in a code shift keying digital modulation scheme. The use of both binary phase shift keying (BPSK) and quaternary phase shift keying (QPSK) to modulate the code bits is investigated. The communications signal is used as the radar signal to implement a pseudo-random BPSK or QPSK coded radar. The symbol error rate (SER) of the communication system is determined through Monte Carlo simulations and compared to an SER upper bound for M-ary frequency shift keying. The radar signal's periodic autocorrelation function (PACF) and periodic ambiguity function are also examined demonstrating the schemes potential for use in a low probability of intercept radar application. The radar signal's characteristics are compared when using pseudo-random BPSK and QPSK modulations.

Supervised Deep Hashing for Hierarchical Labeled Data

Recently, hashing methods have been widely used in large-scale image retrieval. However, most existing supervised hashing methods do not consider the hierarchical relation of labels,which means that they ignored the rich semantic information stored in the hierarchy. Moreover, most of previous works treat each bit in a hash code equally, which does not meet the scenario of hierarchical labeled data. To tackle the aforementioned problems, in this paper, we propose a novel deep hashing method, called supervised hierarchical deep hashing (SHDH), to perform hash code learning for hierarchical labeled data. Specifically, we define a novel similarity formula for hierarchical labeled data by weighting each level, and design a deep neural network to obtain a hash code for each data point. Extensive experiments on two real-world public datasets show that the proposed method outperforms the state-of-the-art baselines in the image retrieval task.