Multilevel Coding Research Articles

The Population-Centered Medical Model: a method of practice for public health physicians

Abstract Background Public Health Physicians (PHPs) in Canada occupy a liminal space between medicine and public health. Current practice frameworks for the care of individual patients by physicians do not account for the complexity of working with communities and populations for health. Similarly, frameworks for public health practice do not account for the roles and responsibilities of physicians in public health. A method of practice that outlines how public health physicians care for populations is vital for training and development of practice for this specialty group within medicine and public health. Methods Constructivist Grounded Theory methods were used in this study. Ethics approval was obtained through The Western University Health Sciences Research Ethics Board. Semi-structured interviews were conducted with eighteen (18) currently practicing PHPs across Canada. Data was analysed iteratively using constant comparison, multi-level coding, and memo writing. Thick description and reflexivity were employed to enhance rigour. Results The key finding is the elucidation of the Population-Centered Medical Model. In this empirically grounded model, PHPs bring values, knowledge and stances to their practice of Public Health Medicine. PHPs consider the population as patient, along with ethical obligations that flow from the physician to the population as a consequence. The process of caring for populations involves both diagnosis and intervention, with a focus on systems and prevention. It relies on knowledge sharing and relationship building between the physician and the population. Conclusions This is the first empirical model to describe the practice of PHPs. The model firmly grounds PHP practice in both medicine (diagnosis and intervention, the construction of a patient) and public health (focus on populations, systems and prevention). It also presents an opportunity to develop a general model of medical practice for n patients, where n can range between 1 and N. Key messages • The Population-Centered Medical Model is an empirically grounded model that describes the work of Public Health Physicians in Canada and grounds practice firmly in medicine and in public health. • Public Health Physicians consider populations as patients. They diagnose and intervene for health, with a focus on systems and prevention, by building relationships and sharing knowledge.

Excitation and manipulation of super cavity solitons in multi-stable passive Kerr resonators

We report on the theoretical analysis as well as the numerical simulations about the nonlinear dynamics of cavity solitons in a passive Kerr resonator operating in the multistable regime under the condition of a sufficiently strong pump. In this regime, the adjacent tilted cavity resonances might overlap, thus leading to the co-existence of combinatory states of temporal cavity solitons and the extended modulation instability patterns. The cavity in the regime of multistablity may sustain distinct families of cavity solitons, vividly termed as super cavity solitons with much higher intensity and broader spectra if compared with those in the conventional bi-stable regime. The description of such complex cavity dynamics in the multstable regime requires either the infinite-dimensional Ikeda map, or the derived mean-field coupled Lugiato-Lefever equations by involving multiple contributing cavity resonances. With the latter model, we revealed the existence of different orders of super cavity solitons, whose stationary solutions were obtained by using the Newton-Raphson algorithm. Along this line, with the continuation calculation, we have plotted the Hopf / saddle-node bifurcation curves, thus identifying the existing map of the stable and breathing (super) cavity solitons. With this defined parameter space, we have proposed an efficient method to excite and switch the super cavity solitons by adding an appropriate intensity (or phase) perturbation on the pump. Such deterministic cavity soliton manipulation technique is demonstrated to underpin the multi-level coding, which may enable the large capacity all-optical buffering based on the passive fiber ring cavities.

External Factors and Endogenous Elements Fostering Critical Thinking of Tertiary EFL Learners in China: A Grounded Theory Study

The cultivation of critical thinking (CT) skills is a fundamental aim within the realm of higher education. It assumes particular significance within the domain of Teaching English as a Foreign Language (TEFL). This study directs its focus on the Chinese tertiary TEFL context and endeavours to explicate what the external factors are, as well as endogenous elements and ways to foster students’ critical thinking. Methodologically, the study adopted grounded theory (GT) and drew upon qualitative data gathered through interviews with 36 participants, including both students and instructors recruited from prestigious universities, mid-tier colleges, and less developed college across China. The data analysis, utilizing NVivo12 software, encompasses a multilevel coding process, including open, axial, and selective coding, in accordance with the principles of GT. The outcome of this meticulous analysis results in the formulation of a comprehensive model revealing the interplay among external influences, endogenous elements, and ways to foster the development of CT skills among tertiary English as a Foreign Language (EFL) students. The implications of these findings extend pedagogically to multiple stakeholders within the tertiary TEFL context.

Extending the reach of multi-core fiber via Voronoi constellations with concatenated multilevel coding.

This Letter proposes a novel, to the best of our knowledge, coded modulation scheme for randomly coupled multi-core fiber (RC-MCF) via multidimensional (MD) constellation with concatenated two-level multilevel coding (MLC). In the proposed system, the 16-dimensional (16D) Voronoi constellation (VC), naturally fitting with the 16 degrees of freedom of a four-core fiber (two quadratures, two polarizations, and four cores), is generated by a latticed-based shaping method to provide higher shaping gains. Moreover, combining it with the concatenated two-level MLC can further achieve better performance-complexity trade-off. It is demonstrated by simulation results of long-haul multi-channel RC-MCF transmission that the proposed coded modulation scheme for four-core fiber transmission offers 77% reduction in the number of decoding operations and up to 21% (585 km) reach increase over the conventional bit-interleaved coded modulation scheme for quadrature amplitude modulation.

Poor Medication Access as a Driver of Excess Heart-Failure Readmissions Among Patients Living in Economically Deprived Neighborhoods

BackgroundPatients residing in socioeconomically deprived neighborhoods experience higher hospital readmission rates after hospitalization for heart failure (HF). The role of medication access in the excessive readmissions in this group is poorly understood. This study explored patients’ perspectives on medication access by individuals living in socioeconomically deprived neighborhoods who had experienced HF readmission. MethodsWe conducted semistructured in-depth interviews with 25 patients (mean age 61 ± 9 years, 96% Black, 40% women) who were readmitted with acute HF at Emory Healthcare hospitals and were living in highly deprived neighborhoods (top decile of the Social Deprivation Index). Qualitative descriptive analyses of the interviews were performed by using a multilevel coding strategy. ResultsMost patients (84%) highlighted medications as a driver of HF readmission. Patients’ reported reasons for lack of medication access included medication costs (60%), having access to refills only through an emergency department or hospitalization (36%), limited access to transportation (12%), and limited understanding of medications’ role in disease management (12%). ConclusionLack of access to medications for patients with HF who live in socioeconomically distressed neighborhoods exacerbate excess hospitalizations in this vulnerable population. This study focuses on patients’ perspectives and experiences and identifies some potentially high-value areas to focus on in trying to enhance access and adherence to evidence-based therapies.

Pyrolysis of Al-Based Metal-Organic Frameworks to Carbon Dot-Porous Al2 O3 Composites With Time-Dependent Phosphorescence Colors for Advanced Information Encryption.

Phosphorescent materials with time-dependent phosphorescence colors (TDPCs) have great potential in advanced optical applications. Synthesis of such materials is attractive but challenging. Here, a series of carbon dot-porous Al2 O3 composites exhibiting distinctive TDPC characteristics is prepared by high-temperature pyrolysis of Al-based metal-organic frameworks NH2 -MIL-101(Al). The composite synthesized at 700 °C (CDs@Al2 O3 -700) shows an obvious change in phosphorescence color from blue to green after removing the excitation light of 280nm. Photophysical analysis reveals that two emission centers in CDs, namely carbon core and surface states, are responsible for the short-lived blue phosphorescence (96ms) and long-lived green phosphorescence (911ms), respectively. The combination of blue and green phosphorescence with different decay rates triggering the interesting TDPC phenomenon. CDs@Al2 O3 -700 has a significantly high phosphorescence quantum yield of up to 41.7% and possesses an excellent optical stability against water, organic solvents, and strong oxidants, which benefits from the multi-confinement of CDs by the porous Al2 O3 matrix through rigid network, strong space constraint, and stable covalent bonding. Based on the TDPC property, multilevel coding patterns composed of CDs@Al2 O3 are successfully fabricated for advanced dynamic information encryption.

Virus for Women Employees: Exploring the Stereotypical Beliefs of the Leaders about their Female Followers

The never-ending gender discrimination in societies needs multidimensional exploration to understand its causes. Gender stereotyping has remained one of the foremost causes of gender discrimination in the workplace. This study strived to explore the stereotypical thinking and beliefs about women employees in the minds of their office leaders and discusses how these stereotypes play role in management of talent and performance of female employees. With the qualitative approach, this study has used hermeneutic phenomenology as the method of exploration. The data was collected with purposive sampling from managerial leaders, working in private companies whose followers include women employees. Nineteen in-depth interviews were conducted with a question designed from theory, expert and construct validity. The data were analyzed with multi-level coding and thematic analysis. The results revealed that managerial leaders have work-related, family-related and personal stereotypes about their female followers. They generalize that women employees are less ambitious, less professional, over occupied an emotional. They believe that they feel need to micromanage the females as they require more guidance. Those organizations that believe to maintain the diversity in employees should regularly organize training sessions to neutralize the stereotypes in the minds of their managers so that they could not hamper the progression of their female followers.
 
 Keywords: Stereotypical Beliefs; Female Followers; Leadership; Organizational Behavior

Real-Time FPGA Investigation of Potential FEC Schemes for 800G-ZR/ZR+ Forward Error Correction

Forward error correction (FEC) performance down to 1e-15 bit error rate (BER) of a open FEC code (OFEC), which was recently proposed for the 800G inter-data center interconnect (DCI) standard, is verified with a 100-piece-FPGA implementation at a record 400-Gbps throughput. Besides the OFEC, we also investigate the cons and pros of the concatenated staircase and Hamming code (CFEC) and multilevel codes (MLC) of a concatenated Low-Density Parity-Check (LDPC) and Turbo Product Code (TPC), which are the candidate schemes for the 800G-ZR FEC. The OFEC performance as a function of decoding iterations of Soft-in Soft-out (SISO) and Hard-in Hard-out (HIHO) is investigated, and FPGA emulations reveal the existence of an error flare of the OFEC with two SISO iterations and an severe error floor with one HIHO iteration even with four SISO iterations. Further investigations on different combinations of SISO and HIHO iterations, revealed that three SISO and two HIHO iterations are the optimal choice. Based on this iteration configuration, we studied the methods that decreasing the test patterns (TP) of SISO decoder and the soft bits to reduce the implementation complexity. Then we proposed the simplified OFEC scheme for 800G-ZR application, providing 1.81e-2 pre-FEC BER threshold with half power dissipation of standard OFEC, achieving a trade-off between the error correction performance and power dissipation. Finally, we investigated the performance of performance enhanced OFEC with 24.3% overhead and 2.5e-2 pre-FEC threshold, and finally, FEC candidates for the 800G-ZR+ applications are studied, indicating that the OFEC and channel polarized multilevel coding (CP MLC) are the most promising schemes.

Интертекстуальность и трансформация архетипа как основа полисемии современной сказки-модификации

In the modern English-language literary space the genre of short prose, based on the plots of classical fairy tales and addressed primarily to an adult audience, is extremely popular. Over half a century already, this genre has emerged as a separate discourse (in this article, the authors call it a “Reimagined Fairy Tale,” considering the memory of the genre). Such modificated fairy tale is simultaniously the result of the postmodern world perception (intertextuality, playfulness, gamification, multilevel text, irony, etc.) and a critical thought (deconstruction, denial of logocentrism), and represents an extensive material for research both from the point of view of literary criticism and from interdisciplinary positions. Using the example of the modern literary tale by R. Shirman “Hunger,” which is based on the folk story about Hansel and Gretel, the authors attempt to trace how the multilevel coding of the text takes place using the transformation of Jungian archetypes and deconstruction of binary oppositions that underlie them on the one hand, and literary and religious reminiscences, and allusions on the other. The authors trace how the text passes into the category of open ones and allows the reader to choose himself which of the meanings of the tale is closer to him. According to the authors, this methodology is applicable to all texts of a given genre and can be productive as a way of reading, and also useful for clarifying the genre features of a modern fairy tale-modification.

Performance Analysis of Multiple Input Multiple Output (MIMO) Multi-Carrier Code-Division Multiple Access (MC-CDMA) Combined with Quasi-Orthogonal Space Time Block Coding (QO-STBC) in Rayleigh Fading Channel

The need for a communication system with a higher data rate and mobility grows along with information and communication technology development. Combining MC-CDMA with the MIMO system and supporting the system with a good transmit diversity technique is a promising idea to provide the needed communication system, especially in high mobility conditions. MC-CDMA can support ubiquitous communications without affecting the achievable BER and is more capable of high-speed mobility. It integrates the benefit of both OFDM and CDMA. On the other hand, QO-STBC increases the bit rate without using additional bandwidth to transmit diversity in the MIMO system. So, this study proposed a system combining the MIMO MC-CDMA system with QO-STBC. The proposed system is investigated under high mobility conditions to see the system's performance. The simulation results show that our system performs better than the MC-CDMA STBC system and the QOSTBC system but not better than the MC-CDMA multilevel coding scheme. To reach the value of BER 10−3, MC-CDMA multilevel Coding requires less power, around 5 dB, than the proposed system.

Abstract 14706: Poor Medication Access as a Driver of Excess Heart Failure Readmissions in Deprived Neighborhoods

Background: Disparities in heart failure (HF) outcomes exist in the United States, in part, due to social determinants of health. Individuals from racial and ethnic minority groups report the highest rates of cost-related delays in care and worse access to high-quality medical therapy. We have previously demonstrated that individuals residing in more deprived neighborhoods experience higher readmissions, and Black patients are more likely to reside in deprived neighborhoods than White patients. Here, we engaged patients from the most deprived neighborhoods to understand drivers of excess readmission from the patient perspective. Methods: We conducted semi-structured in-depth interviews with 25 patients (mean age 61 ± 9 years, 96% Black, 40% female) readmitted with HF at Emory Healthcare hospitals, and living in a neighborhood in the top 10% of the Social Deprivation Index. Qualitative descriptive analysis of the interviews was performed using a multilevel coding strategy. Results: Patients in this cohort had a mean EF 39 ± 19%, and experienced 3.2 ± 2.5 readmissions in the preceding 12 months. Most patients (84%) highlighted lack of access to medications as a driver of hospital readmission. Representative quotes from individual patients are highlighted in the Table. Patients reported the etiology of their lack of medication access included medication costs (64%), only having access to re-fills through the emergency room or hospitalization (36%), low health literacy (12%), and limited access to transportation (8%). Conclusion: Lack of access to medications for patients with HF who live in socioeconomically deprived neighborhoods poses a challenge to reducing the burden of HF. Providing cost-effective and sustainable access to medications for patients with HF from low resource settings is a potential solution to decrease the number of HF hospitalization and readmissions in this vulnerable patient population.

Geometric Constellation Shaping for Concatenated Two-Level Multi-Level Codes

This paper studies a learning approach to geometric shaping (GS) for concatenated two-level multi-level codes (MLC). Unlike standard bit-interleaved coded modulation (BICM), the proposed MLC protects only the least reliable bits (LRBs) by an inner code, and thereby efficiently reduces complexity associated with inner soft-decision (SD) decoding compared to the BICM without performance degradation. We propose a new loss function for training a geometric constellation shape in the proposed MLC, leading to maximization of the achievable rate. More specifically, considering the different coding structures for the most reliable bits (MRBs) and the LRBs, the proposed loss function combines two different functions: the union bound on a bit error rate (BER) for the MRBs and the generalized mutual information (GMI) for the LRBs. We demonstrate by simulations of wavelength division multiplexing (WDM) optical fiber systems that the proposed loss function offers a performance gain over the conventional cross entropy-based loss function. Furthermore, it is demonstrated that the proposed MLC with GS outperforms the conventional BICM with GS in terms of a transmission distance, even with significantly lower SD decoding complexity.

Continuous-variable quantum key distribution with low-complexity information reconciliation.

Information reconciliation is an essential step of continuous-variable quantum key distribution (CV-QKD) because its efficiency affects both the maximum transmission distance and the final secret key rate of the whole system. Slice reconciliation can achieve high secret key rates for the CV-QKD systems under high signal-to-noise ratios (SNRs). However, it suffers from the high designing cost of the error-correcting codes in the multi-level coding and multi-stage decoding step. To reconcile one set of data with fixed SNR, multiple error-correcting codes with different code rates need to be designed. If the channel environment changed, the code rates need to change along to maintain high reconciliation efficiency, making it complicated and costly. In this paper, we introduce polar codes into slice reconciliation and proposed a scheme that is simply constructed, effectively performed, and well adapted to the systems with wide-range and variational SNRs. Simulation results show that the proposed scheme offers reconciliation efficiency over 95% for the systems with SNRs range from 1 to 10, which can support the systems with high secret key rates. The decrease of complexity and the increase of secret key rate have great significance for a practical CV-QKD system.

Dimming Control Scheme of Visible Light Communication Based on Joint Multilevel Time-Shifted Coding

Dimming control is an essential objection in the signal designing of visible light communication (VLC), which requires improving the communication performance of the system as much as possible while considering the illumination quality. Here, we studied the problem of high-efficiency transmission in an indoor VLC multi-core light-emitting diode (LED) communication model while considering dimming constraints, and propose a dimming method based on joint multilevel multi-LED time-shifted coding (ML-MTSC). The scheme utilizes the code structure of time-shifted space–time codes to encode and uses pulse amplitude modulation (PAM) to expand it to achieve the dimming control function in the proposed scenario. Simulation results show that the ML-MTSC dimming control scheme proposed in this paper has improved spectral efficiency and error performance compared with the traditional scheme.

Digging Deeper: Understanding Trajectories and Experiences of Shared Decision-Making for Primary Prevention ICD Implantation

BackgroundShared decision-making using a decision aid is required for patients undergoing implantation of primary prevention implantable cardioverter-defibrillators (ICD). It is unknown how much this process has impacted patients’ experiences or choices. Effective shared decision-making requires an understanding of how patients make ICD decisions. A qualitative key informant study was chosen to capture the breadth of patients’ experiences making ICD decisions in the context of required shared decision-making. Methods and ResultsWe conducted in-depth interviews with 20 patients referred to electrophysiology clinics for the consideration of primary prevention ICD implantation. Purposeful sampling from a prior survey study evaluating mandated shared decision-making was based on patient characteristics and responses to the initial survey questions. Qualitative descriptive analysis of the interviews was performed using a multilevel coding strategy. Patients’ paths to an ICD decision often involved multiple visits with multiple clinicians. However, the decision aid was almost exclusively provided to the patient during electrophysiology clinic visits. Some patients used the numeric data in the decision aid to make an ICD decision based on the risk–benefit profile; others made decisions based on other data or based on trust in clinicians’ recommendations. Patients highlighted information related to living with the device as particularly important in helping them to make their ICD decisions. Some patients struggled with the emotional aspects of making an ICD decision. ConclusionsPatients’ ICD decision-making paths poses a challenge to episodic shared decision-making and may make tools such as decision aids perfunctory if used solely during the electrophysiology visit. Understanding patients’ ICD decision-making paths, especially in the context of encounters with primary cardiologists, can inform the implementation strategies of shared decision-making help to enhance its impact. Components of decision aids focusing on the experience of living with an ICD rather than probabilistic data may also be more impactful, although the nature of their impact will differ.

Rate-Adaptive Concatenated Multi-Level Coding With Novel Probabilistic Amplitude Shaping

This paper proposes a new probabilistic amplitude shaping (PAS) approach for concatenated two-level multi-level coding (MLC). The proposed system is based on a concatenated forward error correction (FEC) scheme where outer codes are serially concatenated with inner two-level MLC. This concatenated two-level MLC scheme has recently been shown to have a potential for achieving better performance-complexity trade-offs than the conventional bit-interleaved coded modulation (BICM). Meanwhile, PAS has recently been demonstrated to offer remarkable performance gains as well as rate adaptivity. However, the majority of existing works on PAS assume the use of the binary reflected Gray code as a bit-labeling, and its application to coded modulation schemes with other bit-labelings, such as two-level MLC, may not be straightforward. In this paper, we devise a bit-labeling scheme and propose a new PAS structure for an efficient integration of PAS with two-level MLC systems. More specifically, we propose to generate <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">signed</i> amplitude symbols with the distribution matcher (DM) for maximizing both coding and shaping gains achieved by two-level MLC and PAS, respectively, while the conventional PAS generates <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">unsigned</i> amplitude symbols. It is demonstrated by simulation results that, with 256QAM and inner polar codes, the proposed two-level MLC with PAS simultaneously offers 75% reduction in the number of required inner encoding and soft-decision (SD) decoding operations for given outer and inner FEC code lengths, and up to 0.3 dB performance gain over the conventional PAS scheme.

Inter-Multilevel Super-Orthogonal Space-Time Coding Scheme for Reliable ZigBee-Based IoMT Communications.

The Internet of Things (IoT) technology has revolutionized the healthcare industry by enabling a new paradigm for healthcare delivery. This paradigm is known as the Internet of Medical Things (IoMT). IoMT devices are typically connected via a wide range of wireless communication technologies, such as Bluetooth, radio-frequency identification (RFID), ZigBee, Wi-Fi, and cellular networks. The ZigBee protocol is considered to be an ideal protocol for IoMT communication due to its low cost, low power usage, easy implementation, and appropriate level of security. However, maintaining ZigBee’s high reliability is a major challenge due to multi-path fading and interference from coexisting wireless networks. This has increased the demand for more efficient channel coding schemes that can achieve a more reliable transmission of vital patient data for ZigBee-based IoMT communications. To meet this demand, a novel coding scheme called inter-multilevel super-orthogonal space–time coding (IM-SOSTC) can be implemented by combining the multilevel coding and set partitioning of super-orthogonal space–time block codes based on the coding gain distance (CGD) criterion. The proposed IM-SOSTC utilizes a technique that provides inter-level dependency between adjacent multilevel coded blocks to facilitate high spectral efficiency, which has been compromised previously by the high coding gain due to the multilevel outer code. In this paper, the performance of IM-SOSTC is compared to other related schemes via a computer simulation that utilizes the quasi-static Rayleigh fading channel. The simulation results show that IM-SOSTC outperforms other related coding schemes and is capable of providing the optimal trade-off between coding gain and spectral efficiency whilst guaranteeing full diversity and low complexity.

Multilevel Coding for Physical-Layer Security

In any transmission scheme, security against eavesdroppers is of importance. Contrary to classical encryption, security directly at the physical layer can be achieved by applying suited coding and modulation schemes. In this paper, coded modulation schemes, i.e., the use of higher-order constellations, is studied for generating both security against a wiretapper and reliability for the legitimate user. Specifically, a multilevel coding (MLC) scheme is considered. The influence of the constellation, in particular its cardinality and its dimensionality, on the gained security is assessed. As LSB component code, a practical secure coding scheme based on punctured LDPC codes is used. The security level for the employed LDPC code ensembles within MLC constructions is examined with an adapted density evolution technique. Results from numerical simulations cover the theoretical considerations and match with the derived asymptotic behavior. The results are compared to the situation when straightforwardly applying a binary code according to the BICM approach.

Mutual Information Analysis for Generalized Spatial Modulation Systems With Multilevel Coding

Mutual Information Analysis for Generalized Spatial Modulation Systems With Multilevel Coding

Multiedge-type low-density parity-check codes for continuous-variable quantum key distribution

Continuous-variable quantum key distribution utilizes an ensemble of coherent states of light to distribute secret encryption keys between two parties. One of the challenges is thereby the requirement of capacity approaching error correcting codes in the low signal-to-noise (SNR) regime (SNR < 0 dB). Multilevel coding (MLC) combined with multistage decoding (MSD) can solve this challenge in combination with multi-edge-type low-density parity-check (MET-LDPC) codes which are ideal for low code rates in the low SNR regime due to degree-one variable nodes. However, the complexity of designing such highly efficient codes remains an open issue. Here, we introduce the concept of generalized extrinsic information transfer (G-EXIT) charts for MET-LDPC codes and demonstrate how this tool can be used to analyze their convergence behavior. We calculate the capacity for each level in the MLC-MSD scheme and use G-EXIT charts to exemplary find codes for some given rates which provide a better decoding threshold compared to previously reported codes. In comparison to the traditional density evolution method, G-EXIT charts offer a simple and fast asymptotic analysis tool for MET-LDPC codes.