Line Code Research Articles

CCSDS 131.2-B-1 telemetry transmitter: A VHDL IP core and a validation architecture on board RTG4 FPGA

During the last years, improvement in the resolution of Earth observation satellite instruments has been leading to the necessity of high throughput transmitters, featuring efficient encoding and modulation schemes. For that reason, the Consultative Committee for Space Data Systems (CCSDS) issued the CCSDS 131.2-B-1 standard describing the architecture of a flexible telemetry transmitter featuring Serially Concatenated Convolutional Codes (SCCCs). Such flexibility allows CCSDS 131.1-B-1 implementations to take full advantage of the channel by dynamically changing the coding-rate and type of modulation (Adaptive Code and Modulation, ACM).This work presents a VHDL Telemetry Transmitter IP Core fully compliant to the CCSDS 131.2-B-1 standard. The IP Core is technology independent and as such can be fitted on different Field Programmable Gate Arrays (FPGAs), including space grade devices, realizing a broad spectrum of solutions that differ in terms of transmission throughput, radiation hardness and cost figures. In particular, this work shows that the IP Core is able to reach 259.3 Mbaud and 1355 Mbit/s data transfer on the Microsemi RTG4 FPGA. To verify the IP Core functionalities on board the different FPGAs, register-transfer level (RTL) and post-layout simulations were performed through a custom verification environment. The latter allowed 100% functional and code coverage according to a dedicated test plan. Finally, the IP was validated through an appropriate validation system on board the Microsemi RTG4 FPGA exploiting a hardware/software co-design approach.

A Block-Based Arithmetic Entropy Encoding Scheme for Medical Images

The digitization of human body, especially for treatment of diseases can generate a large volume of data. This generated medical data has a large resolution and bit depth. In the field of medical diagnosis, lossless compression techniques are widely adopted for the efficient archiving and transmission of medical images. This article presents an efficient coding solution based on a predictive coding technique. The proposed technique consists of Resolution Independent Gradient Edge Predictor16 (RIGED16) and Block Based Arithmetic Encoding (BAAE). The objective of this technique is to find universal threshold values for prediction and provide an optimum block size for encoding. The validity of the proposed technique is tested on some real images as well as standard images. The simulation results of the proposed technique are compared with some well-known and existing compression techniques. It is revealed that proposed technique gives a higher coding efficiency rate compared to other techniques.

A Novel Bit plane Compression based Reversible Data Hiding Scheme with Arnold Transform

Reversible data hiding (RDH) is an active research area in the field of information security. The RDH scheme allows the transmission of a secret message by embedding it into a cover image, and the receiver can recover the original cover image along with the extraction of the secret message. In this paper, we propose a bit plane compression based RDH scheme to hide a sequence of secret message bits into a grayscale image. In the proposed method, a selected bit plane of the cover image will be compressed using run-length encoding (RLE) scheme. Further, the RLE sequence has been efficiently encoded as a binary sequence using Elias gamma encoding method. The Elias gamma encoded bit sequence concatenated with the secret message bits are used to replace the selected bit plane after performing a sequence of Arnold transform. The Arnold transform helps to find a new scrambled version of the bit plane which is very close to the original bit plane to ensure the visual quality of the stego image. The RLE is a lossless compression technique, therefore recovery of the original image is possible by the receiver. The experimental study of the proposed scheme on the images from standard image dataset (USC-SIPI image dataset) shows that the proposed scheme outperforms the existing scheme in terms of the visual quality of the stego image without compromising the data embedding rate.

Space–Time Line Code for Enhancing Physical Layer Security of Multiuser MIMO Uplink Transmission

In this article, we investigate a secure uplink multiple-input multiple-output communication system, in which the multiple users transmit information to a legitimate access point (AP) when a passive eavesdropper exists. A secure multiple access method is proposed for single-antenna users by employing space-time line codes (STLCs), which enables noncoherent detection at the legitimate AP without channel state information (CSI) and achieves full spatial diversity. While extending the secure STLC scheme from the single-antenna to two-antenna users by combining the STLC with artificial noise (AN) injection, we design a low-complexity AN signals with the optimal power control scheme. The proposed AN is ensured to be eliminated after STLC decoding at the legitimate AP, while sustained in eavesdropper's received signals as interference. Theoretical sum secrecy rates are derived by considering time-varying fading channels with the uncertainty of CSI at the users, and the numerical results verify that the proposed STLC schemes outperform the existing secure transmission schemes in terms of the sum secrecy rate.

A generic encoding and operation scheme for mixed aperture three and four hexagonal discrete global grid systems

ABSTRACT Discrete Global Grid Systems (DGGSs) are an emerging data model for integration and analysis of big Earth data. Current research on hexagonal DGGSs focuses mainly on the pure aperture, which limits application of resolution and may cause data redundancy. The mixed aperture hexagonal DGGS provides a new and flexible scheme that can optimize data precision by designing the most suitable grid resolution. This paper proposes a generic encoding and operation scheme for the mixed aperture 3 and 4 hexagonal DGGSs. A planar mathematical model with unique location representation was constructed. Based on this model, this paper designed an encoding scheme and gave relevant operational properties and rules. A generic method of extending the planar scheme to the surface of an icosahedron was then designed and spherical grids were obtained by projection. The conversion between geographical coordinates and codes was also provided. The proposed scheme has a more complete theoretical basis than existing schemes and can be applicable to different aperture sequences. Experiments show that the code addition efficiency of the proposed algorithm is superior to existing hexagonal grid systems. A case study with ocean salinity hexagonal data demonstrated the flexibility of the proposed scheme.

RZ Line Coding Scheme With Direct Laser Modulation for Upgrading Optical Transmission Systems

Abstract This study reports the efficient use of a direct laser modulated response measured with the return-to-zero coding scheme in optical transmission systems. The measured direct laser modulated response has a bit rate of 1.2 Gbps for an optical fiber cable of a transmission length of 10 km. The eye diagram analyzer is used to calculate the maximum quality factor and minimum bit error rate of the proposed model. The maximum quality factor is 531.2, and the minimum bit error rate tends to zero for the same optical fiber channel length compared with that of the previous model. The proposed model provides better results than the previous model. The figures of the proposed model are more stable than those of its previous counterpart. Bit error rate approximately tends to zero in the proposed model.

Line Codes for Communication Systems

The coder is a generic device where exist a big types diversity. In base digital systems, the coder is a device that codifies the active input position in a number, normally, binary natural. If we have N inputs they are codified with n bits, N=2

INAPPROPRIATE ENDOTRACHEAL TUBE (ETT) CUFF PRESSURE AND ITS RELATION TO VENTILATOR-ASSOCIATED PNEUMONIA (VAP) IN INTENSIVE CARE UNIT (ICU)

TYPE: Abstract Publication TOPIC: Respiratory Care PURPOSE: The respiratory therapist has a major role in preventing nosocomial infection in ICU. One of the most common infections with mechanically ventilated patients is VAP. Inappropriate ETT Cuff measure is one of the main risk factors for microaspiration and VAP. To help reduce this issue, we aimed to observe and investigate medical errors during respiratory therapy in ICU. METHODS: An observational study conducted done by three trained researchers over a period of 65 days, in two ICUs with a total of 56 ICU Beds capacity. The observational study was followed by 20 semi-structured interviews with the staff of respiratory therapy department in each ICU to explore their understanding of the observed incidents and the contributing factors. All discussions and detailed notes taken were transcribed, qualitatively analyzed using line by line coding and then synthesized into narrative themes. We used NVivo-11 to organize and manage the data. RESULTS: During the observational periods, a total of twenty-four patients developed VAP. Among these patients eight patients (33%) were exposed to inappropriate ETT cuff pressure. No fatality was reported as a result of VAP until the study was concluded. CONCLUSIONS: Patients with ETT cuff pressures which are outside the recommended range may be at increased risk of developing VAP and further complications. Poor cuff pressure management could increase ICU days and prolong the use of mechanical ventilation. CLINICAL IMPLICATIONS: We recommended that the staff be educated about the consequences of poor cuff pressure management and the complications which may arise as a result. DISCLOSURE: No significant relationships. KEYWORDS: VAP, patient safety, mechanical ventilation

Efficient human-machine control with asymmetric marginal reliability input devices.

Input devices such as motor-imagery brain-computer interfaces (BCIs) are often unreliable. In theory, channel coding can be used in the human-machine loop to robustly encapsulate intention through noisy input devices but standard feedforward error correction codes cannot be practically applied. We present a practical and general probabilistic user interface for binary input devices with very high noise levels. Our approach allows any level of robustness to be achieved, regardless of noise level, where reliable feedback such as a visual display is available. In particular, we show efficient zooming interfaces based on feedback channel codes for two-class binary problems with noise levels characteristic of modalities such as motor-imagery based BCI, with accuracy <75%. We outline general principles based on separating channel, line and source coding in human-machine loop design. We develop a novel selection mechanism which can achieve arbitrarily reliable selection with a noisy two-state button. We show automatic online adaptation to changing channel statistics, and operation without precise calibration of error rates. A range of visualisations are used to construct user interfaces which implicitly code for these channels in a way that it is transparent to users. We validate our approach with a set of Monte Carlo simulations, and empirical results from a human-in-the-loop experiment showing the approach operates effectively at 50-70% of the theoretical optimum across a range of channel conditions.

Expedited Stroke Imaging With Electromagnetic Polar Sensitivity Encoding

There is a significant demand for fast and accurate electromagnetic (EM) imaging of stroke in emergency situations. This article presents a method for encoding the raw S-parameters from the Cartesian matrix to polar grid coordinates with weighting coefficients based on the receiver antenna spatial sensitivity. The polar sensitivity encoding (PSE) scheme is based on the fact that the receiver sensitivity generally has an encoding effect and, in this case, it is applied during the transformation of S-matrices to polar grid, which is geometrically congruent with the shape of the head. The PSE scheme alleviates the need for highly accurate and intricate forward and inverse EM field solvers and mitigates the introduction of numerical errors in addition to the unavoidable experimental uncertainties. The simulation and experimental results demonstrate that the PSE method is robust to head shifts up to about 5 mm and accurate in localizing strokes in less than a second.

Moving towards IoT Based Digital Communication: An Efficient Utilization of Power Spectrum Density for Smart Cities

The future of the Internet of Things (IoT) is interlinked with digital communication in smart cities. The digital signal power spectrum of smart IoT devices is greatly needed to provide communication support. The line codes play a significant role in data bit transmission in digital communication. The existing line-coding techniques are designed for traditional computing network technology and power spectrum density to translate data bits into a signal using various line code waveforms. The existing line-code techniques have multiple kinds of issues, such as the utilization of bandwidth, connection synchronization (CS), the direct current (DC) component, and power spectrum density (PSD). These highlighted issues are not adequate in IoT devices in smart cities due to their small size. However, there is a need to design an effective line-code method to deal with these issues in digital IoT-based communication for smart technologies, which enables smart services for smart cities. In this paper, the Shadow Encoding Scheme (SES) is proposed to transmit data bits efficiently by using a physical waveform in the smart cities’ ecosystem. SES provides a reliable transmission over the physical medium without using extra bandwidth and with ideal PSD. In it, the shadow copy of the repeating bitstream is forwarded, rather than repeating the actual stream again and again. The PSD is calculated with the help of mathematical equations to validate SES. MATLAB simulator is used to simulate SES and compared with other well-known digital line-code techniques. The bit error rate is also compared between SES and the chirp spread spectrum (CSS) for the specific data frames. The coordinates of the PSD graph are also shown in tabular form, which shows a vivid picture of the working conditions of various line codes.

PPTPP: a novel therapeutic peptide prediction method using physicochemical property encoding and adaptive feature representation learning.

Peptide is a promising candidate for therapeutic and diagnostic development due to its great physiological versatility and structural simplicity. Thus, identifying therapeutic peptides and investigating their properties are fundamentally important. As an inexpensive and fast approach, machine learning-based predictors have shown their strength in therapeutic peptide identification due to excellences in massive data processing. To date, no reported therapeutic peptide predictor can perform high-quality generic prediction and informative physicochemical properties (IPPs) identification simultaneously. In this work, Physicochemical Property-based Therapeutic Peptide Predictor (PPTPP), a Random Forest-based prediction method was presented to address this issue. A novel feature encoding and learning scheme were initiated to produce and rank physicochemical property-related features. Besides being capable of predicting multiple therapeutics peptides with high comparability to established predictors, the presented method is also able to identify peptides' informative IPP. Results presented in this work not only illustrated the soundness of its working capacity but also demonstrated its potential for investigating other therapeutic peptides. https://github.com/YPZ858/PPTPP. Supplementary data are available at Bioinformatics online.

Interference‐resilient spectrum sharing with collision detection and data recovery for cognitive radio networks

SummaryData recovery under collision of primary/secondary users in cognitive radio networks is largely an unaddressed problem. Existing approaches require either (a) retransmissions, (b) interference‐free alignment of transmission parameters, or (c) prior knowledge for data recovery. In contrast to the existing approaches, the paper proposes estimation of channel state information based on received collided frames and recommends techniques for spectrum sharing, collision detection, and data recovery. Specifically, based on estimated channel vector, interference‐resilient spectrum‐sharing protocol and techniques are proposed for (a) identification of primary user (PU) activity before (or during) secondary user's (SU's) transmission, (b) MIMO channel estimation under collision, (c) optimal pilot permutation, and (d) interference cancellation (with/without receiver diversity). Results are reported for different baseband modulation techniques under frequency selective/flat fading channel scenarios that demonstrate the efficacy of a proposed work.

Metacommunication process during a 3-day digital storytelling workshop for patients recovering from hematopoietic cell transplantation

Abstract Purpose: The purpose of this study was to qualitatively analyze metacommunication during the digital storytelling (DST) workshop process for patients undergoing hematopoietic cell transplantation (HCT). Methods: HCT survivors who had undergone transplant within the past 2 years were recruited at a cancer center in the Phoenix Metropolitan area. Participants (M age = 51.5 years) attended a 3-day DST workshop telling and creating digital stories around their HCT experiences. Using a constructivist grounded theory approach, line by line coding and content analysis were conducted with four research team members. Results: Four themes emerged from the data: (1) communal connection; (2) expressing and processing emotions; (3) self-empowerment; and (4) multi-dimensional coping. Participants described telling and sharing their story with other HCT patients as therapeutic. Conclusion: DST shows promise as a potential coping tool and offers multiple dimensions of the role of narrative as a coping technique, in community building, and in patient-centered contexts within HCT.

A New Lossless DNA Compression Algorithm Based on A Single-Block Encoding Scheme

With the emergent evolution in DNA sequencing technology, a massive amount of genomic data is produced every day, mainly DNA sequences, craving for more storage and bandwidth. Unfortunately, managing, analyzing and specifically storing these large amounts of data become a major scientific challenge for bioinformatics. Therefore, to overcome these challenges, compression has become necessary. In this paper, we describe a new reference-free DNA compressor abbreviated as DNAC-SBE. DNAC-SBE is a lossless hybrid compressor that consists of three phases. First, starting from the largest base (Bi), the positions of each Bi are replaced with ones and the positions of other bases that have smaller frequencies than Bi are replaced with zeros. Second, to encode the generated streams, we propose a new single-block encoding scheme (SEB) based on the exploitation of the position of neighboring bits within the block using two different techniques. Finally, the proposed algorithm dynamically assigns the shorter length code to each block. Results show that DNAC-SBE outperforms state-of-the-art compressors and proves its efficiency in terms of special conditions imposed on compressed data, storage space and data transfer rate regardless of the file format or the size of the data.

A simple encoder scheme for distributed residual video coding

Rate-Distortion (RD) performance of Distributed Video Coding (DVC) is considerably less than that of conventional predictive video coding. In order to reduce the performance gap, many methods and techniques have been proposed to improve the coding efficiency of DVC with increased system complexity, especially techniques employed at the encoder such as encoder mode decisions, optimal quantization, hash methods etc., no doubt increase the complexity of the encoder. However, low complexity encoder is a widely desired feature of DVC. In order to improve the coding efficiency while maintaining low complexity encoder, this paper focuses on Distributed Residual Video Coding (DRVC) architecture and proposes a simple encoder scheme. The main contributions of this paper are as follows: 1) propose a bit plane block based method combined with bit plane re-arrangement to improve the dependency between source and Side Information (SI), and meanwhile, to reduce the amount of data to be channel encoded 2) present a simple iterative dead-zone quantizer with 3 levels in order to adjust quantization from coarse to fine. The simulation results show that the proposed scheme outperforms DISCOVER scheme for low to medium motion video sequences in terms of RD performance, and maintains a low complexity encoder at the same time.

Uplink NOMA Random Access Systems With Space–Time Line Code

This work proposes a random access system with uplink non-orthogonal multiple access (NOMA), where users transmit their packets by using the space-time line code (STLC) to fully exploit the spatial diversity without channel state information at the receiver. More specifically, users with a single antenna estimate channel gain from the base station (BS) with two antennas, encode the information using the STLC, and then transmit it using transmit power control so that the received power of their packets at the BS can be one of the predetermined values. The BS decodes the received packets via STLC decoding and the successive interference cancellation technique. Owing to spatial diversity, we show that the proposed scheme improves energy efficiency in comparison to the conventional system with a single antenna BS.

Optimal Non-Coherent Detector for Ambient Backscatter Communication System

The joint probability density function (pdf) of the received signal of an ambient backscatter communication system is derived, assuming that on-off keying (OOK) is performed at the tag to form non-return to zero (NRZ) line codes, and that the ambient radio frequency (RF) signal is white Gaussian. The pdf of the received signal is then utilized to design two different types of non-coherent detectors. The first detector directly uses the received signal to perform a hypothesis test. The second detector first estimates the channel based on the observed signal and then performs the hypothesis test. Test statistics and the optimal decision threshold of the detectors are derived. The energy detector is shown to be an approximation of the second detector. For cases where the reader is able to avoid or cancel the direct interference from the RF source (e.g., through successive interference cancellation), a third detector is given as a special case of the first detector. Numerical results show that the first detector outperforms the second detector, although the second detector is computationally simpler.

A miniaturization of the UWB monopole antenna for wireless baseband transmission

In this paper, a novel Monopole patch antenna with dimension 22*20*1.6 mm3 is presented to enhance the bandwidth and minimize the size of the antenna. The power divider and etched a slot on the ground plane are significant improvements in the proposed antenna. Based on this approach, the ultra-wideband antenna for 2.4 GHz to 9.6 GHz frequency band is a significant improvement. The flat gain from -5dB to 2.3dB over the frequency band of operation, which is provided to transmit and receive the output line code from Rapid Signal Flux Quantum (RSFQ) chip directly without modulation techniques (WBT) by these antennas between two different environments (4K-300k). The nearly radiation patterns of the presented antenna are bidirectional at E-plane and omnidirectional at H-plane.

An iPWM Line-Coding-Based Wireline Transceiver With Clock -Domain Encoding for Compensating Up To 27-dB Loss While Operating at 0.5-to-0.9 V and 3-to-16 Gb/s in 65-nm CMOS

This article presents a clock-domain-based integrated pulsewidth modulation (PWM) (iPWM) line-coding scheme to enable equalization while operating at low supply voltages. While conventional equalizers such as feedforward equalizer (FFE), decision feedback equalizer (DFE), and continuous-time linear equalizer (CTLE) are present on the high-bandwidth data path, the proposed iPWM-based line-coding-based approach moved the equalization logic away from the data path and into the subrate clock path. As a result, the proposed clock-domain iPWM line coding can operate at low supply voltages. An energy-efficient implementation of the proposed scheme was demonstrated. Fabricated in a 65-nm CMOS process, the proposed transceiver operates over a data-rate range of 3-16 Gb/s from 0.5 to 0.9 V. Equalization in this transceiver was done using iPWM and a passive CTLE. Operating at 10 Gb/s at 0.65 V, the proposed transceiver is capable of equalizing up to 27 dB of channel loss at energy efficiency of 1.8 pJ/bit.