Non-Orthogonal Multiple Access for Hybrid VLC-RF Networks with Imperfect Channel State Information

The present contribution proposes a general framework for the energy efficiency analysis of a hybrid visible light communication (VLC) and Radio Frequency (RF) wireless system, in which both VLC and RF subsystems utilize nonorthogonal multiple access (NOMA) technology. The proposed framework is based on realistic communication scenarios as it takes into account the mobility of users, and assumes imperfect channel-state information (CSI). In this context, tractable closed-form expressions are derived for the corresponding average sum rate of NOMA-VLC and its orthogonal frequency division multiple access (OFDMA)-VLC counterparts. It is shown extensively that incurred CSI errors have a considerable impact on the average energy efficiency of both NOMA-VLC and OFDMAVLC systems and hence, they should not be neglected in practical designs and deployments. Interestingly, we further demonstrate that the average energy efficiency of the hybrid NOMA-VLCRF system outperforms NOMA-VLC system under imperfect CSI. Respective computer simulations corroborate the derived analytic results and interesting theoretical and practical insights are provided, which will be useful in the effective design and deployment of conventional VLC and hybrid VLC-RF systems

La prevalencia del desgaste dental entre un grupo de adultos Yemeníes.

This study aimed at investigating tooth wear prevalence and determining the associated factors among a group of Yemeni adults. It is a preliminary cross-sectional and analytical investigation conducted on 600 participants aged 20–50 years. The participants were purposively selected from two main cities (Sana’a and Aden) with an equal sample size and divided equally by gender. For administering a questionnaire, interviews were conducted with all participants before clinically examining them. Using the Tooth Wear Index (TWI), tooth wear was assessed. Data were analyzed using the chi-square test to identify the relationship between tooth wear and associated factors., Tooth wear was prevalent among 78.67% of the participants; of which 64.83% were in anterior teeth, 63.83% in posterior teeth, 74% in maxillary teeth, and approximately 74.5% in mandibular teeth. It also was 100% prevalent in the 31-40 and 41-50 age groups, while it was 67.2% in the 20-30 age group. This showed that tooth wear prevalence was significantly higher in the two oldest groups than in the youngest group (p<0.001). Moreover, khat chewing, location, highly frequent consumption of foods and high frequency of acidic drinks consumption were critical indicators of tooth wear. Besides, a low education level, smoking and a low socio-economic status were associated with tooth wear. Finally, the study revealed that tooth wear is highly prevalent among adults in two Yemeni cities, and socio-behavioral risk indicators such as khat chewing and cigarette smoking have a significantly association with tooth wear.Este estudio tuvo como objetivo investigar la prevalencia del desgaste dental y determinar los factores asociados en un grupo de adultos yemeníes. Es una investigación preliminar analítica y transversal que se lleva a cabo en 600 participantes de entre 20 y 50 años. Los participantes fueron seleccionados a propósito de dos ciudades principales (Sana’a y Aden) con un tamaño de muestra igual y divididos por igual por género. Para administrar un cuestionario, se realizaron entrevistas con todos los participantes antes de examinarlos clínicamente. Usando el Índice de Desgaste Dental, se evaluó el desgaste dental. Los datos se analizaron utilizando la prueba de chi-cuadrado para identificar la relación entre el desgaste dental y los factores asociados. El degaste dental tuvo una prevalencia del 78,67% de los participantes; de los cuales 64.83% en dientes anteriores, 63.83% en dientes posteriores, 74% en dientes maxilares y aproximadamente 74.5% en dientes mandibulares. Fue 100% prevalente en los grupos de edad 31-40 y 41-50, mientras que la prevalencia fue 67.2% en el grupo de edad 20-30. Esto demostró que la prevalencia del desgaste dental fue significativamente mayor en los dos grupos de personas mayores que en el grupo más joven (p<0.001). Además, mascar khat, la ubicación, el consumo muy frecuente de alimentos y la alta frecuencia de bebidas ácidas fueron indicadores críticos del desgaste dental. Además, el bajo nivel educativo, el tabaquismo y el bajo nivel socioeconómico se asociaron con el degaste dental. Finalmente, el estudio reveló que el desgaste dental es altamente prevalente entre los adultos en dos ciudades yemeníes, y los indicadores de riesgo socioconductual como la masticación de khat y el tabaquismo tienen una asociación significativa con el desgaste dental

IML-ViT: Benchmarking Image Manipulation Localization by Vision Transformer

Advanced image tampering techniques are increasingly challenging the trustworthiness of multimedia, leading to the development of Image Manipulation Localization (IML). But what makes a good IML model? The answer lies in the way to capture artifacts. Exploiting artifacts requires the model to extract non-semantic discrepancies between manipulated and authentic regions, necessitating explicit comparisons between the two areas. With the self-attention mechanism, naturally, the Transformer should be a better candidate to capture artifacts. However, due to limited datasets, there is currently no pure ViT-based approach for IML to serve as a benchmark, and CNNs dominate the entire task. Nevertheless, CNNs suffer from weak long-range and non-semantic modeling. To bridge this gap, based on the fact that artifacts are sensitive to image resolution, amplified under multi-scale features, and massive at the manipulation border, we formulate the answer to the former question as building a ViT with high-resolution capacity, multi-scale feature extraction capability, and manipulation edge supervision that could converge with a small amount of data. We term this simple but effective ViT paradigm IML-ViT, which has significant potential to become a new benchmark for IML. Extensive experiments on five benchmark datasets verified our model outperforms the state-of-the-art manipulation localization methods.Code and models are available at \url{https://github.com/SunnyHaze/IML-ViT}

On the Sum Secrecy Rate of Multi-User Holographic MIMO Networks

The emerging concept of extremely-large holographic multiple-input multiple-output (HMIMO), beneficial from compactly and densely packed cost-efficient radiating meta-atoms, has been demonstrated for enhanced degrees of freedom even in pure line-of-sight conditions, enabling tremendous multiplexing gain for the next-generation communication systems. Most of the reported works focus on energy and spectrum efficiency, path loss analyses, and channel modeling. The extension to secure communications remains unexplored. In this paper, we theoretically characterize the secrecy capacity of the HMIMO network with multiple legitimate users and one eavesdropper while taking into consideration artificial noise and max-min fairness. We formulate the power allocation (PA) problem and address it by following successive convex approximation and Taylor expansion. We further study the effect of fixed PA coefficients, imperfect channel state information, inter-element spacing, and the number of Eve's antennas on the sum secrecy rate. Simulation results show that significant performance gain with more than 100\% increment in the high signal-to-noise ratio (SNR) regime for the two-user case is obtained by exploiting adaptive/flexible PA compared to the case with fixed PA coefficients.Comment: 7 pages, 7 figures, submitted to IEEE ICC 202

Deep Q-Learning-based Resource Allocation in NOMA Visible Light Communications

Visible light communication (VLC) has been introduced as a key enabler for high-data rate wireless services in future wireless communication networks. In addition to this, it was also demonstrated recently that non-orthogonal multiple access (NOMA) can further improve the spectral efficiency of multi-user VLC systems. In this context and owing to the significantly promising potential of artificial intelligence in wireless communications, the present contribution proposes a deep Q-learning (DQL) framework that aims to optimize the performance of an indoor NOMA-VLC downlink network. In particular, we formulate a joint power allocation and LED transmission angle tuning optimization problem, in order to maximize the average sum rate and the average energy efficiency. The obtained results demonstrate that our algorithm offers a noticeable performance enhancement into the NOMA-VLC systems in terms of average sum rate and average energy efficiency, while maintaining the minimum convergence time, particularly for higher number of users. Furthermore, considering a realistic downlink VLC network setup, the simulation results have shown that our algorithm outperforms the genetic algorithm (GA) and the differential evolution (DE) algorithm in terms of average sum rate, and offers considerably less run-time complexity.publishedVersionPeer reviewe

S100A8/A9 regulates CD11b expression and neutrophil recruitment during chronic tuberculosis

Neutrophil accumulation is associated with lung pathology during active tuberculosis (ATB). However, the molecular mechanism or mechanisms by which neutrophils accumulate in the lung and contribute to TB immunopathology are not fully delineated. Using the well-established mouse model of TB, our new data provide evidence that the alarmin S100A8/A9 mediates neutrophil accumulation during progression to chronic TB. Depletion of neutrophils or S100A8/A9 deficiency resulted in improved Mycobacterium tuberculosis (Mtb) control during chronic but not acute TB. Mechanistically, we demonstrate that, following Mtb infection, S100A8/A9 expression is required for upregulation of the integrin molecule CD11b specifically on neutrophils, mediating their accumulation during chronic TB disease. These findings are further substantiated by increased expression of S100A8 and S100A9 mRNA in whole blood in human TB progressors when compared with nonprogressors and rapidly decreased S100A8/A9 protein levels in the serum upon TB treatment. Furthermore, we demonstrate that S100A8/A9 serum levels along with chemokines are useful in distinguishing between ATB and asymptomatic Mtb-infected latent individuals. Thus, our results support targeting S100A8/A9 pathways as host-directed therapy for TB