Adaptive Fuzzy Logic Deep-Learning Equalizer for Mitigating Linear and Nonlinear Distortions in Underwater Visible Light Communication Systems

Underwater visible light communication (UVLC) has recently come to light as a viable wireless carrier for signal transmission in risky, uncharted, and delicate aquatic environments like seas. Despite the potential of UVLC as a green, clean, and safe alternative to conventional communication methods, it is challenged by significant signal attenuation and turbulent channel conditions compared to long-distance terrestrial communication. To address linear and nonlinear impairments in UVLC systems, this paper presents an adaptive fuzzy logic deep-learning equalizer (AFL-DLE) for 64 Quadrature Amplitude Modulation-Component minimal Amplitude Phase shift (QAM-CAP)-modulated UVLC systems. The proposed AFL-DLE is dependent on complex-valued neural networks and constellation partitioning schemes and utilizes the Enhanced Chaotic Sparrow Search Optimization Algorithm (ECSSOA) to improve overall system performance. Experimental outcomes demonstrate that the suggested equalizer achieves significant reductions in bit error rate (55%), distortion rate (45%), computational complexity (48%), and computation cost (75%) while maintaining a high transmission rate (99%). This approach enables the development of high-speed UVLC systems capable of processing data online, thereby advancing state-of-the-art underwater communication.

Investigation of FBMC-OQAM Equalization with Real Interference Prediction Algorithm Properties for MIMO Transmission Scheme

Increasing the data transfer rate is an urgent task in cellular, high-frequency (HF) and special communication systems. The most common way to increase the data rate is to expand the bandwidth of the transmitted signal, which is often achieved through the use of multitone systems. One such system is the filter bank multicarrier (FBMC). In addition, speed improvements are achieved using multi-input-multi-output (MIMO) systems. In this study, we developed an algorithm for equalizing FBMC signals with offset-QAM modulation (OQAM) with self-interference compensation due to its correlation properties in a MIMO channel with memory. An analytical derivation of the proposed algorithm and an analysis of the computational complexity are given. According to the results of simulation modeling and a comparative analysis of performance in terms of the bit error rate and error vector magnitude with solutions with similar computational complexity, a similar level of performance was shown compared to a more complex parallel multistage algorithm, and a better performance was demonstrated compared to a one-tap algorithm.

Performance Analysis of Turbo Codes, LDPC Codes, and Polar Codes over an AWGN Channel in the Presence of Inter Symbol Interference

This paper discusses the results of simulations relating to the performances of turbo codes, low density parity check (LDPC) codes, and polar codes over an additive white Gaussian noise (AWGN) channel in the presence of inter symbol interference, denoting the disturbances that altered the original signal. To eliminate the negative effects of inter symbol interference (ISI), an equalizer was used at the level of the receiver. Practically, two types of equalizers were used: zero forcing (ZF) and minimum mean square error (MMSE), considering the case of perfect channel estimation and the case of estimation using the least square algorithm. The performance measure used was the modification of the bit error rate compared to a given signal to noise ratio; in this sense, the MMSE equalizer offered a higher performance than the ZF equalizer. The aspect of channel equalization considered here is not novel, but there have been very few works that dealt with equalization in the context of the use of turbo codes, especially LDPC codes and polar codes for channel coding. In this respect, this research can be considered a contribution to the field of digital communications.

Do men and women have different musculoskeletal symptoms at the same musculoskeletal discomfort level?

Owing to biological and social factors, illness-related musculoskeletal symptoms tend to vary between men and women. However, in the past, conceptualised discomfort metrics were applied uniformly to both genders. This study aimed to develop a scale to measure musculoskeletal discomfort that compares the symptoms between men and women. The scale aimed to determine the gender-based response patterns related to symptoms. A total of 707 men and 1302 women reported their symptoms on a body map. Factor analysis and item response theory were used to differentiate the identified symptoms in the construction of a musculoskeletal discomfort scale. Differences in work exposure appeared to explain the symptom patterns between men and women. The scale had eight levels, and it was found that at the same level of discomfort, men and women reported symptoms in different body regions.Practitioner summary: On this discomfort scale, the response patterns of men and women were categorised into eight levels. Symptoms differed by gender at the same musculoskeletal discomfort level. This is in contrast to previous studies in which scales were devised without considering differences between the genders.Abbreviations: WMSDs: work-related musculoskeletal disorders; BMI: body mass index; FA: factor analysis; IRT: item response theory; KMO: Kaiser-Meyer-Olkin; BST: Bartlett's test of sphericity; F: factor loading; h2: communality; α: Cronbach's alpha; ωt: McDonald's omega; ai: parameters of discrimination of the items; bik: parameters of difficulty of response categories; θj: latent trait; RMSEA: root mean square error of approximation; CFI: comparative fit index; TLI: Tucker-Lewis index; odu: musculoskeletal discomfort units; RA: rarely; OF: often; AL: always.

Comparison of the Nonlinear Dynamic Pre- and Post-LED Equalization

Visible Light Communications (VLC) have gained much popularity lately. In such a system, a white LED (Light-Emitting Diode) plays a double role as a light source and a transmitter. The main problem here is that the LED exhibits a low bandwidth and high nonlinearity, so the equalization of the LED nonlinear dynamic response is necessary. For this, various equalizers are used. This paper compares the pre- and post-equalizer performance in terms of the received signal quality for a channel that includes a nonlinear element of limited bandwidth, such as an LED. Multilevel Pulse Amplitude Modulation (PAM) was selected as the signal format, as well as a variant of the Volterra series equalizer as the compensating element. The results obtained may be used for the correction of the dynamic characteristics of LEDs applied in VLC systems. For the sake of comparison, we used Modulation Error Ratio (MER) values at the receiver output. The dynamic nonlinear behavior was modeled by a Wiener-Hammerstein device, whereas the post/pre-equalizer was based on the dynamic deviation reduction-based Volterra series. The obtained results indicate that the post- and pre-equalizer performed comparably for the linear/moderately nonlinear channels and for a high noise level. In the case of high nonlinearity and a large SNR (Signal-to-Noise Ratio) values, the post-equalizer performed somewhat better in terms of MER by a few dB at maximum.

Non-Linear Hopped Chaos Parameters-Based Image Encryption Algorithm Using Histogram Equalization

Multimedia wireless communications have rapidly developed over the years. Accordingly, an increasing demand for more secured media transmission is required to protect multimedia contents. Image encryption schemes have been proposed over the years, but the most secure and reliable schemes are those based on chaotic maps, due to the intrinsic features in such kinds of multimedia contents regarding the pixels’ high correlation and data handling capabilities. The novel proposed encryption algorithm introduced in this article is based on a 3D hopping chaotic map instead of fixed chaotic logistic maps. The non-linearity behavior of the proposed algorithm, in terms of both position permutation and value transformation, results in a more secured encryption algorithm due to its non-convergence, non-periodicity, and sensitivity to the applied initial conditions. Several statistical and analytical tests such as entropy, correlation, key sensitivity, key space, peak signal-to-noise ratio, noise attacks, number of pixels changing rate (NPCR), unified average change intensity randomness (UACI), and others tests were applied to measure the strength of the proposed encryption scheme. The obtained results prove that the proposed scheme is very robust against different cryptography attacks compared to similar encryption schemes.

Passive Equalization Networks-Efficient Synthesis Approach for High-Speed Signal Integrity Characterization

High data rates challenges and long traces from current state-of-the-art systems imply high attenuation. In the present article, we will present a detailed process of synthesis of equalizers, for choosing the correct one for a given application. The methods are based on scattering parameters applied on interconnections modeled as microstrip or stripline. Firstly, one may have an overview of types of equalizers, passive, active, and adaptive ones, and a detailed filter synthesis is applied in microwave systems having as start point the insertion loss of a given trace on a given substrate. Next, time domain analyses offer a better understanding of the performance of the interconnect, based on eye diagram inspection and the variation of waveforms with time. Finally, we will present results based on simulation of the equalizers network in a microstrip technology followed by discussions and conclusions. The study proposes to use equalizers in either the transmitter or receiver point, proposes a bridge equalizer with the cost of additional elements but improved constant input, output impedance, and also a new variant for single ended trace based on microwave resonator is proposed. Performance is demonstrated by results from simulations.

Socioeconomic Inequalities in Health among Armenian Adolescents

We aimed to study the hypothesis of socioeconomic equalization in health among Armenian adolescents participating in the Health Behavior in School-Aged Children 2013/14 survey. Classes corresponding to the ages 11, 13, and 15 were selected using a clustered sampling design. Multiple logistic regression analyses were used. In a nationally representative sample of 3679 students, adolescents with a low family socioeconomic position (SEP) had greater odds of reporting less than good health (odds ratio (OR) = 2.81, 95% CI = 2.25-3.51), low psychosocial well-being (OR = 1.94, 95% CI = 1.44-2.61), or psychosomatic symptoms (OR = 1.29, 95% CI = 1.07-1.56). Low levels of material well-being were associated with a higher likelihood of reporting less than good health (OR = 1.32, 95% CI = 1.06-1.65) or low psychosocial well-being (OR = 1.27, 95% CI = 1.04-1.54). The presence of both risk factors had a synergistic effect on having low psychosocial well-being (P-interaction = 0.031). Refuting the equalization hypothesis, our results indicate that low SEP might be strongly related to adolescent health in middle-income countries such as Armenia. Low material well-being also proved important, and, for further research, we hypothesized an association via decreased peer social status and compromised popularity.

A deeper mining on the protein composition of VA-MENGOC-BC®: An OMV-based vaccine against N. meningitidis serogroup B and C

The protein composition of an Outer Membrane Vesicle (OMV) preparation that constitutes the active pharmaceutical ingredient of VA-MENGOC-BC®, an effective vaccine against Neisseria meningitidis serogroups B, and C is presented. This preparation has a high lipid content and five abundant membrane proteins (FetA, PorA, PorB, RmpM, and Opc), constituting approximately 70% of the total protein mass. The protein composition was determined by combining the use of the Hexapeptide Ligand Library and an orthogonal tandem fractionation of tryptic peptides by reverse-phase chromatography at alkaline and acid pH. This approach equalizes the concentration of tryptic peptides derived from low- and high-abundance proteins as well as considerably simplifying the number of peptides analyzed by LC-MS/MS, enhancing the possibility of identifying low-abundance species. Fifty-one percent of the proteins originally annotated as membrane proteins in the genome of the MC58 strain were identified. One hundred and sixty-eight low-abundance cytosolic proteins presumably occluded within OMV were also identified. Four (NadA, NUbp, GNA2091, and fHbp), out of the five antigens constituting the Bexsero® vaccine, were detected in this OMV preparation. In particular, fHbp is also the active principle of the Trumenba® vaccine developed by Pfizer. The HpuA and HpuB gene products (not annotated in the MC58 genome) were identified in the CU385 strain, a clinical isolate that is used to produce this OMV. Considering the proteins identified here and previous work done by our group, the protein catalogue of this OMV preparation was extended to 266 different protein species.

Beyond health aid: would an international equalization scheme for universal health coverage serve the international collective interest?

It has been argued that the international community is moving 'beyond aid'. International co-financing in the international collective interest is expected to replace altruistically motivated foreign aid. The World Health Organization promotes 'universal health coverage' as the overarching health goal for the next phase of the Millennium Development Goals. In order to provide a basic level of health care coverage, at least some countries will need foreign aid for decades to come. If international co-financing of global public goods is replacing foreign aid, is universal health coverage a hopeless endeavor? Or would universal health coverage somehow serve the international collective interest?Using the Sustainable Development Solutions Network proposal to finance universal health coverage as a test case, we examined the hypothesis that national social policies face the threat of a 'race to the bottom' due to global economic integration and that this threat could be mitigated through international social protection policies that include international cross-subsidies - a kind of 'equalization' at the international level.The evidence for the race to the bottom theory is inconclusive. We seem to be witnessing a 'convergence to the middle'. However, the 'middle' where 'convergence' of national social policies is likely to occur may not be high enough to keep income inequality in check.The implementation of the international equalization scheme proposed by the Sustainable Development Solutions Network would allow to ensure universal health coverage at a cost of US$55 in low income countries-the minimum cost estimated by the World Health Organization. The domestic efforts expected from low and middle countries are far more substantial than the international co-financing efforts expected from high income countries. This would contribute to 'convergence' of national social policies at a higher level. We therefore submit that the proposed international equalization scheme should not be considered as foreign aid, but rather as an international collective effort to protect and promote national social policy in times of global economic integration: thus serving the international collective interest.