Line Code Research Articles

Longitudinal Qualitative Analysis of the Role and Perspective of the Care Partner During and Four Weeks Following Disclosure of Amyloid PET Scan Results

AbstractBackgroundAmyloid PET scans allow for the visualization of amyloid plaque in the brain, which, in the context of mild cognitive impairment (MCI), signal heightened risk for progression to Alzheimer’s dementia (AD). Disclosure of such results can profoundly impact patients as well as their family care partners. The purpose of this study was to examine the role and perspectives of family care partners during and after the return of amyloid PET results.MethodWe used qualitative description to analyze transcripts of audio‐recorded results disclosure sessions and 4‐week follow‐up interviews of participants with MCI and their care partners who were randomized to the disclosure arm of the Return of Amyloid Imaging Scan Results (RAISR) trial. Focusing on care partners (n = 36), we conducted line by line coding and thematic analysis with the goals of 1) categorizing the frequency and nature of the questions raised by care partners during the open‐ended segment of the disclosure sessions, and 2) describing care partners’ perceptions of their loved one’s results in the month following disclosure.ResultAt disclosure, 13 families received positive for amyloid, and 21 received negative scan results. Care partners of those learning of amyloid positivity asked approximately twice as many questions as those receiving negative results (averaging 5.6 vs. 2.8 questions per session). Seven themes were identified in the questions: study logistics, AD/AD care, result clarification, next steps given result, outside resources, requests for scan images, and “other.” The vast majority of questions fell under AD/AD care (n = 47), followed by questions about study logistics (n = 24). The overarching theme of the week 4 interviews was a general sense of acceptance of the scan results. However, instances of inadequate comprehension of the scans’ implications were noted, particularly among partners of amyloid negative patients, some of whom interpreted the result to mean that their loved one’s MCI was nonprogressive.ConclusionFamily care partners play active roles in eliciting information and clarification during amyloid PET results disclosure. However, our findings regarding care partners of amyloid negative patients affirm that disclosing clinicians should not assume that those who ask fewer questions have an adequate understanding of the information presented.

Reconfigurable Intelligent Surface Assisted Space-Time Line Code for SIMO Transmission

In this contribution, we investigate reconfigurable intelligent surface assisted space-time line code (RIS-STLC) transmission for enhancing the signal quality when the direct link between the transmitter and receiver is blocked. In the context of intelligent transmission by RIS, the concept of index modulation (IM) is integrated into the pursuit of higher spectral efficiency, while a two-step detection is developed to improve the performance. Correspondingly, for blind transmission where the channel information at RIS is not available, the phase at RIS not associated with the channel is considered. Subsequently, the bit-error-rate (BER) performances of the proposed RIS-STLC system conditioned on both the intelligent and blind transmission are quantified. Theoretical analysis and simulation results demonstrate the effectiveness of the development of RIS-STLC.

Model of a 5-MA Linear-Transformer-Driver Accelerator: Transmission-Line-Circuit Method and Three-Dimensional Field-Circuit Coupling Method

A 5-MA-LTD-based, high current accelerator is modeled using transmission line code. And the machine performances are presented for driving short-circuit loads, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Z$ </tex-math></inline-formula> -pinch loads, and bremsstrahlung electron beam diodes. With simulation analysis, it is expected that the short-circuit load current can reach 4.7 MA in 100 ns with ±80 kV LTD charge voltage, and the peak of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Z$ </tex-math></inline-formula> -pinch load current when the machine is conducted with a 0.45 mg wire-array can be high as 4.2 MA, the peak kinetic energy is 49 kJ, and the energy coupling efficiency is estimated as 38%. The physical model of the reflex triode load which is typical electron beam diode is presented in detail. By incorporating the physics-based reflex triode model into a 3-D transient electromagnetic model, the field-circuit coupling simulation can be performed and the results are compared with the circuit model. The results from these two methods are in good agreement. The peak load current when the machine is configured with a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim 0.15~\Omega $ </tex-math></inline-formula> reflex triode load is ~2.8 MA. The energy coupling efficiency to the reflex triode load is 35.8%.

Pilot‐aided 1 × 2 and 2 × 2 space‐time line code systems with transmit antenna selection

SummaryThe space‐time line code (STLC), which has been recently proposed in the literature, assumes fully known channel state information at the transmitter and not the receiver. However, the effective channel gain is still required at the receiver to coherently detect ‐ary quadrature amplitude modulation ( QAM) symbols. In this paper, we propose pilot‐aided STLC systems, which do not require the effective channel gain at the receiver to detect the QAM symbols. In order to further improve the error performance of the proposed schemes, we present the pilot‐aided STLC systems with transmit antenna selection (TAS). Using a more direct and simpler approach, we derive the average symbol error probability (ASEP) of the coherent STLC systems with TAS, which represents the lower bound of the pilot‐aided STLC systems with TAS. For comparison, in a similar manner, we also derive the ASEP of the coherent STLC systems without TAS, which represents the lower bound of the pilot‐aided STLC systems. For pilot‐aided STLC systems with TAS, the gap between the simulated symbol error rate (SER) and the derived theoretical ASEP lower bound is very small. For a given number of transmit antennas, the simulated SER and theoretical ASEP also show that the error performance of the pilot‐aided STLC systems with or without TAS is superior to the pilot‐aided STLC systems with TAS by at least 1.8 dB.

Modulation instability—rogue wave correspondence hidden in integrable systems

The bulk-boundary correspondence is a key feature of topological physics and is universally applicable to Hermitian and non-Hermitian systems. Here, we report a similar universal correspondence intended for the rogue waves in integrable systems, by establishing the relationship between the fundamental rogue wave solutions of integrable models and the baseband modulation instability of continuous-wave backgrounds. We employ an N-component generalized nonlinear Schrödinger equation framework to exemplify this modulation instability-rogue wave correspondence, where we numerically confirm the excitation of three coexisting Peregrine solitons from a turbulent wave field, as predicted by the modulation instability analysis. The universality of such modulation instability-rogue wave correspondence has been corroborated using various integrable models, thereby offering an alternative way of obtaining exact rogue wave solutions from the modulation instability analysis.

Modulation leakage-free continuous-variable quantum key distribution

Distributing cryptographic keys over public channels in a way that can provide information-theoretic security is the holy grail for secure communication. This can be achieved by exploiting quantum mechanical principles in so-called quantum key distribution (QKD). Continuous-variable (CV) QKD based on coherent states, in particular, is an attractive scheme for secure communication since it requires only standard telecommunication technology that can operate at room temperature. However, a recently discovered side-channel created in the process of state preparation leads to a leakage of information about the transmitted quantum state, opening a security loophole for eavesdroppers to compromise the security of the CVQKD system. Here, we present a CVQKD system without this modulation leakage vulnerability. Our implementation is based on a baseband modulation approach and uses an in-phase and quadrature (IQ) modulator for state preparation and radio frequency heterodyne detection together with carefully designed digital signal processing for state measurement. We consider practical aspects in the implementation and demonstrate the generation of a composable secret key secure against collective attacks. This work is a step towards protecting CVQKD systems against practical imperfections of physical devices and operational limitations without performance degradation.

Concept and Implementation of Embedded Magnetic Encoder in Flux-Switching Permanent-Magnet Machines

Rotor angle is essential in permanent-magnet (PM) brushless machines. Recently, an embedded magnetic encoder (EME) scheme, consisted of linear Hall sensors installing inside of the PM machines, has been proposed to sense the flux density and consequently provides rotor position. Compared with traditional optical encoder and resolver, the linear Hall sensor prevails over in both space and cost. The aforementioned scheme is employed successfully in rotor-PM machines, where a PM-excited field rotates at the synchronous speed. In this article, the feasibility of EME in stator-PM flux-switching machine is validated, where PMs are located in stator, resulting in a stationary PM field. The stator slots are selected as installation position of linear Hall sensors to avoid changing the existing structure of machines. The variation of linear Hall signal is due to the changing reluctance of rotor rather than rotating PMs. Then, a decoding algorithm is designed based on an add-up operation, a complex coefficient filter, and a synchronous reference frame phase-locked loop. Finally, experiments on a prototype machine are conducted to validate the effectiveness of EME scheme under both speed-varying and load-varying conditions.

Chaotic-Enabled Phase Modulation in Time-Modulated Arrays for Secure Transmission

The “time” factor in time-modulated arrays (TMAs) offers a new degree of freedom for securing wireless communication. However, the widely used periodic time modulation introduces limited randomness for eavesdropping receivers, and thus gives weak security. To meet this challenge, this work proposes a TMA with chaotic-enabled phase modulation (CPM) for secure transmission. The proposed CPM technique offers the chaos features of high randomness, unpredictability, and initial condition sensitive characteristic, to increase the information uncertainty for eavesdropping receivers. An optimization-based time sequence design approach is introduced to design optimal CPM time sequences for secure transmission in a given direction. Thus, a variety of security strategies including beam scanning, directional modulation (DM), and chaotic encryption are simultaneously enabled by the optimized CPM time sequence. Moreover, the CPM is a radio frequency (RF)-domain security technique without requiring any baseband modulation modules, which exhibits a simplified hardware architecture. Numerical analysis and experimental results are presented to illustrate the effectiveness of the proposed CPM technique. The results indicate that the security is improved by lowering the bit error rate (BER) between the legitimate receiver and the transmitter, and reducing the mutual information between eavesdropping receivers and the transmitter.

Sensor Fault Estimation for Nonlinear Complex Networks With Time Delays Under Saturated Innovations: A Binary Encoding Scheme

In this paper, the fault estimation problem is dealt with for a class of nonlinear time-delayed complex networks with bounded stochastic noises and sensor faults under the binary encoding scheme (BES). A first-order differential model with a random bias is utilized to describe the sensor fault to cater for real practice. By using the BES, the measurement signal is first encoded to a bit string and then transmitted to the estimator where the bit string is decoded. During the transmission, random bit errors may occur in the bit string due to the channel noises. A set of Bernoulli distributed random variables is employed to characterize the occurrence of the bit errors. To enhance the robustness of the estimation performance to the random bit errors, the saturation function is introduced in the estimator to constrain the innovations. The target of this paper is to design a fault estimator such that the estimation error dynamics is exponentially ultimately bounded in mean square with a minimized ultimate bound. Sufficient conditions are first developed for the existence of the desired fault estimator via stochastic analysis and inequality manipulations. Then, the estimator gain matrices are obtained by solving a set of matrix inequalities. Finally, a simulation example is presented to illustrate the effectiveness of the proposed fault estimation method.

Linear Precoding for Space-Time Line Code-Based Multicast Systems

In this article, a linear precoding weight vector is designed to enhance the minimum signal-to-interference plus noise ratio (SINR) of a space-time line code (STLC)-based multicast users. To solve the intractable minimum SINR maximization problem, the optimal weight vector for each STLC user is derived, and then, the individual optimal weight vectors are linearly combined. The designed linear precoding vector improves the minimum and average SINR of the multicast users as verified by numerical results. Numerical results also verify that the STLC-based multicast is a promising scheme, especially, if a transmitter has a large number of transmit antennas and the additive noises are severe at the users.

An Implantable Neuromorphic Sensing System Featuring Near-sensor Computation and Send-on-Delta Transmission for Wireless Neural Sensing of Peripheral Nerves.

This paper presents a bio-inspired event-driven neuromorphic sensing system (NSS) capable of performing on-chip feature extraction and "send-on-delta" pulse-based transmission, targeting peripheral-nerve neural recording applications. The proposed NSS employs event-based sampling which, by leveraging the sparse nature of electroneurogram (ENG) signals, achieves a data compression ratio of >125×, while maintaining a low normalized RMS error of 4% after reconstruction. The proposed NSS consists of three sub-circuits. A clockless level-crossing (LC) ADC with background offset calibration has been employed to reduce the data rate, while maintaining a high signal to quantization noise ratio. A fully synthesized spiking neural network (SNN) extracts temporal features of compound action potential signals consumes only 13 μW. An event-driven pulse-based body channel communication (Pulse-BCC) with serialized address-event representation encoding (AER) schemes minimizes transmission energy and form factor. The prototype is fabricated in 40-nm CMOS occupying a 0.32-mm2 active area and consumes in total 28.2 μW and 50 μW power in feature extraction and full diagnosis mode, respectively. The presented NSS also extracts temporal features of compound action potential signals with 10-μs precision.

Practical Schemes on Lightning Energy Suppression in Arresters for Transformers on 10 kV Overhead Distribution Lines

This paper presented an assessment of lightning energy absorption by dedicated surge arresters (SA <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DT</sub> ), which are provided to protect the distribution transformers on 10kV overhead distribution lines (OHLs). A hybrid Partial Element Equivalent Circuit-Multi-conductor Transmission Line (PEEC-MTL) code was applied to evaluate lightning surges on SA <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DT</sub> . This method has the capability of modeling both short and long wires in OHL systems and is verified numerically and experimentally. A Monte Carlo procedure was adopted to assess the fault rate (FR) of SA <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DT</sub> . It is found that the direct lightning strokes to the phase wire are the primary threat to the SA <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DT</sub> , compared with the strokes to the poles as well as indirect strokes to the ground or structure nearby. Several protection schemes are identified, and their performance is evaluated from the aspects of lightning protection and economic cost. The full shielding wire (SW) scheme performs the best, but with the most expensive protection cost. The lightning energy absorption by SA <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DT</sub> can be suppressed significantly by installing extra SAs on the adjacent poles. The scheme of two or four extra SAs together with a partial SW can achieve a balanced performance of protection effect and economic cost for the OHL. The SW for a section of the OHL alone is not enough to the lightning protection for SA <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DT</sub> .

On the Construction of Self-Complementary Codes and their Application in the Problem of Information Hiding

Line codes are widely used to protect against errors in data transmission and storage systems, to ensure the stability of various cryptographic algorithms and protocols, to protect hidden information from errors in a stegocontainer. One of the classes of codes that find application in a number of the listed areas is the class of linear self-complementary codes over a binary field. Such codes contain a vector of all ones, and their weight enumerator is a symmetric polynomial. In applied problems, self-complementary [n, k]-codes are often required for a given length n and dimension k to have the maximum possible code distance d(k, n). For n < 13, the values of d(k, n) are already known. In this paper, for self-complementary codes of length n=13, 14, 15, the problem is to find lower bounds on d(k, n), as well as to find the values of d(k, n) themselves. The development of an efficient method for obtaining a lower estimate close to d(k, n) is an urgent task, since finding the values of d(k, n) in the general case is a difficult task. The paper proposes four methods for finding lower bounds: based on cyclic codes, based on residual codes, based on the (u-u+v)-construction, and based on the tensor product of codes. On the joint use of these methods for the considered lengths, it was possible to efficiently obtain lower bounds, either coinciding with the found values of d(k, n) or differing by one. The paper proposes a sequence of checks, which in some cases helps to prove the absence of a self-complementary [n, k]-code with code distance d. In the final part of the work, on the basis of self-complementary codes, a design for hiding information is proposed that is resistant to interference in the stegocontainer. The above calculations show the greater efficiency of the new design compared to the known designs.

Perturbed Fokas–Lenells equation: Lie symmetry analysis, complexitons and baseband modulation instability

In this work, Lie symmetry analysis method is utilized to find the complex soliton solutions of the perturbed Fokas–Lenells equation. In this direction, first of all, we obtained the infinitesimals of the Fokas–Lenells equation with the help of the Lie symmetry method. After that, we reduced the Fokas–Lenells equation into the highly nonlinear system of an ordinary differential equation. Consequently, with the application of suitable back transformation, complex solitons are formulated for the Fokas–Lenells equation in trigonometric, hyperbolic and exponential functions. Finally, in this work, conditions of stability and instability are discussed with the aid of baseband modulation instability.

Telling a story or reporting the facts? Interpretation and description in the qualitative analysis of applied health research data: A documentary analysis of peer review reports

Interpretative analysis of qualitative data has been likened to a form of creative storytelling. However, analysis of qualitative health research data is often subject to concerns derived from quantitative empiricism such as replicability, bias and impartiality. In applied health research, it seems that qualitative portrayals have become dominated by descriptive reporting at the expense of interpretative accounts.I conducted a documentary analysis based on 32 peer reviewer reports (received 2014–2019) in connection with four interpretative qualitative health research manuscripts.Peer reviewers were mostly positive towards the manuscripts and the findings of the studies seemed to resonate with them. Yet, interpretive analysis was viewed negatively leading to a lack of trust in the findings. Three broad issues seemed to trouble reviewers. First, line by line coding of all data was thought to be paramount in order to assure replicability. Second, it was asserted that verbatim quotations from participants must be included in the findings section otherwise the findings could be considered erroneous. Third, data should be subjected to a comparative analysis based on similarities and differences, rather than an interpretive approach, as this was thought to be more systematic. I offer a reflexive account of my positionality and understandings of interpretative creativity.The art of storytelling through qualitative data seems to have been derided within applied health research, with a push towards reportage of basic facts. Peer reviewers are evaluating creative analyses against a quantitative paradigm. This methodological conservatism is encouraging an oversimplification of the complexity resident in many qualitative datasets.

Multipurpose Cloud-Based Compiler Based on Microservice Architecture and Container Orchestration

Compilation often takes a long time, especially for large projects or when identifying better optimization options. Currently, compilers are mainly installed on local machines and used as standalone software. Despite the availability of several online compilers, they do not offer an efficient all-in-one package for private account management, command line interface (CLI), code advisors, and optimization techniques. Today, the widespread usage of Software as a Service (SaaS) is ever-growing, and compilers are not an exception. In this paper, we describe a symmetric approach to compilation and how to compile code on distributed systems. Although some improvements in cloud compilers have been made, it is possible to harness the potential of the most-modern technologies and architecture patterns toward designing efficient, in-cloud compilers. In this paper, we propose an architecture design of a cloud-based compiler that is fully compatible with orchestration technologies, such as Kubernetes, providing a higher level of scalability, reliability, security, and maintainability. Microservice architecture alongside containerization and orchestration technologies assist us in making a scalable system that provides a high level of availability. We propose this architecture so that the system can handle a higher workload as it receives a large number of compilation requests per second. Distributed compilation is a prominent benefit of this approach, as each phase of the compilation can be executed in a separate server, which supplies a kind of workload mitigation to the whole system. In other words, we propose a new perspective for an intelligent way of advisor, error detection, and optimization of compilers. We also propose an implementation example of the developed architecture. Finally, we analyze the results from an experimental implementation, proving that we can compile code from more than 100k requests concurrently on a cloud cluster with one master node and three worker nodes.

Modified Block Coordinate Descent Method for Intelligent Reflecting Surface-Aided Space-Time Line Coded Systems

The intelligent reflecting surface (IRS) technology can be combined with the space-time line code (STLC) to reduce the channel estimation overhead for adjusting the IRS phase shifts. However, the computational complexity to design the phase shift values of IRS elements can increase prohibitively with the increment of IRS elements. To reduce the design complexity for the IRS-aided STLC system, we propose a modified block coordinate descent (MBCD) algorithm that can simply design the phase shift values of the IRS. The proposed MBCD algorithm can dramatically reduce the computational complexity with no compromise of performance compared to the various existing methods, such as a semidefinite relaxation method, an alternating direction method of multipliers, an analytic constant modulus algorithm, and a complex unit-modulus constraint relaxation method.

Discrete Artificial Algae Algorithm for solving Job-Shop Scheduling Problems

The Job-Shop Scheduling Problem (JSSP) is an NP-hard problem and can be solved with both exact methods and heuristic algorithms. When the dimensionality is increased, exact methods cannot produce proper solutions, but heuristic algorithms can produce optimal or near-optimal results for high-dimensional JSSPs in a reasonable time. In this work, novel versions of the Artificial Algae Algorithm (AAA) have been proposed to solve discrete optimization problems. Three encoding schemes (Random-Key (RK), Smallest Position Value (SPV), and Ranked-Over Value (ROV) Encoding Schemes) were integrated with AAA to solve JSSPs. In addition, the comparison of these three encoding schemes was carried out for the first time in this study. In the experiments, 48 JSSP problems that have 36 to 300 dimensions were solved with 24 different approaches obtained by integrating 3 different coding schemes into 8 state-of-the-art algorithms. As a result of the comparative and detailed analysis, the best results in terms of makespan value were obtained by integrating the SPV coding scheme into the AAA method.

AMCC nonlinear baseband superimposition and extraction aided by proposed interference cancellation for WDM-PON used in 5G mobile fronthaul.

As the demand for mobile Internet capacity explodes, the research on fifth-generation (5G) mobile communication systems has gradually deepened, which has stringent requirements for latency and transmission capacity, especially in the section called mobile fronthaul (MFH). Wavelength division multiplexing passive optical network (WDM-PON) is an attractive technology for 5G MFH which requires an auxiliary management and control channel (AMCC) to achieve efficient network deployment. In previous studies, more research has been done on AMCC superimposition methods and transmission performance on 10 Gbps WDN-PON systems, and the role of AMCC in wavelength management has been studied at the system level. In this paper, we realize non-linear baseband modulation of AMCC signals up to 20 Mbps in a single wavelength 25-Gbps PON system through the distributed feed-back laser and Mach-Zehnder modulator. At the receiving end, we propose a low-complexity interference cancellation method to suppress the interference caused by WDM-PON signals and significantly reduce the bit error rate of AMCC signals. The method realizes a simplified scheme to reconstruct the PON signals by analyzing the characteristics of nonlinear modulation and the reconstructed signals can be applied to the original AMCC signals through filtering and subtraction to eliminate interference. These operations have low complexity and can be easily implemented by analog circuits, thus making it an effective way to improve the quality of AMCC signals. With the help of the proposed method, AMCC transmission at 20 Mbps can be achieved with different modulation depths, which is very promising for 5G MFH.

Ergodic Capacity of Space–Time Line Code Systems With Transmit Antenna Selection

Since a novel diversity technique called a space–time line code (STLC) was invented, previous studies have focused on the analysis of a <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rate-1</i> STLC assuming <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">two</i> receive antennas. For the state-of-the-art STLCs with transmit antenna selection (TAS), in this study, the ergodic capacities of TAS-STLC systems with <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">various code rates</i> are mathematically derived, not only for a TAS-STLC system with two receive antennas but also for those with <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">three</i> or <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">four</i> . To this end, the probability density function of the instantaneous signal-to-noise ratio was characterized. The accuracy of the mathematical analysis was validated by a numerical simulation. This study is significant for investigating the fundamental performance of TAS-STLC systems.