First-Passage Time and Large-Deviation Analysis for Erasure Channels with Memory

This article considers the performance of digital communication systems transmitting messages over finite-state erasure channels with memory. Information bits are protected from channel erasures using error-correcting codes; successful receptions of codewords are acknowledged at the source through instantaneous feedback. The primary focus of this research is on delay-sensitive applications, codes with finite block lengths and, necessarily, non-vanishing probabilities of decoding failure. The contribution of this article is twofold. A methodology to compute the distribution of the time required to empty a buffer is introduced. Based on this distribution, the mean hitting time to an empty queue and delay-violation probabilities for specific thresholds can be computed explicitly. The proposed techniques apply to situations where the transmit buffer contains a predetermined number of information bits at the onset of the data transfer. Furthermore, as additional performance criteria, large deviation principles are obtained for the empirical mean service time and the average packet-transmission time associated with the communication process. This rigorous framework yields a pragmatic methodology to select code rate and block length for the communication unit as functions of the service requirements. Examples motivated by practical systems are provided to further illustrate the applicability of these techniques.Comment: To appear in IEEE Transactions on Information Theor

Wire tomography in the H-1NF heliac for investigation of fine structure of magnetic islands

Electron beam wire tomography in the H-1NF heliac enables high resolution mapping of vacuum flux surfaces with minimal disruption of the plasma operations schedule. Recent experimental results have proven this technique to be a highly accurate and high resolution method for mapping vacuum magnetic islands. Islands of width as small as delta approximately 8 mm have been measured, providing estimates of the internal rotational transform of the island. Point-to-point comparison of the mapping results with computer tracing, in conjunction with an image warping technique, enables systematic exploration of magnetic islands and surfaces of interest. Recent development of a fast mapping technique significantly reduced the mapping time and made this technique suitable for mapping at higher magnetic fields. This article presents recent experimental results and associated techniques.with support from the Australian Research Council Grant No. DP0344361

Three view electronically scanned interferometer for plasma electron density measurements on the H-1 heliac

We report the development of a three view electronically scanned millimeter-wave interferometer for plasma electron density profile measurement on the H-1 heliac. The system utilizes an electronically tunable backward-wave oscillator whose output is incident on a fixed blazed diffraction grating such that sweeping the source frequency effects a spatial scan of the plasma cross section. Two diagonal views essentially span most of the plasma cross section, while the horizontal arm views the lower half of the plasma. The diffracted beams traverse the plasma in <1ms with a spatial resolution ∼20mm. A study of the density projection dependence on magnetic configuration shows that the presence of low-order rational surfaces in the plasma gives rise to sharp density gradients in the vicinity of the surface

Optimized Machine Learning Models For Early Detection Of Alcohol Use Disorder: A Hybrid Approach

Alcohol Use Disorder (AUD) remains a critical global health issue, necessitating the development of advanced diagnostic systems for early and accurate detection. Conventional diagnostic methods often exhibit subjectivity and limited predictive capability, emphasizing the need for intelligent computational techniques. This research introduces a hybrid optimization framework that integrates machine learning models with metaheuristic optimization strategies to enhance AUD detection. By incorporating evolutionary algorithms, such as Genetic Algorithms (GA) and Particle Swarm Optimization (PSO), alongside deep learning techniques, the proposed approach optimally selects features, fine-tunes hyperparameters, and reduces overfitting. A diverse dataset combining clinical, behavioral, and neuroimaging data is used to train and validate the model, ensuring broad applicability across different populations. Comparative evaluations with traditional machine learning models indicate that the hybrid-optimized method substantially improves classification accuracy, sensitivity, and specificity in differentiating AUD from non-AUD cases. Additionally, explainable AI techniques are utilized to improve model interpretability, aiding healthcare professionals in understanding key predictive factors. The results highlight the potential of hybrid optimization in machine learning for AUD diagnosis, contributing to more reliable, data-driven clinical decision-making and early intervention strategies

Tobacco as risk factor for periodontal disease in green marble mine laborers of Rajasthan, India

Aim: To determine the effect of tobacco usage on the severity of periodontal disease in green marble mine laborers. Methods: Marble mine laborers (n=585) aged 15–54 years were selected from four geographic zones in green marble mines area using a stratified random sampling procedure. A total of 517 (88%) laborers participated in the study. The sample were classified as tobacco users, non users, occasional users, ex users and the data regarding form, duration and frequency of tobacco consumption was also collected by personal interviews. Periodontal status was assessed by community periodontal index. Results: Nearly three fourth (71.9%) of the population was tobacco users. Among the smokers, bleeding and calculus accounted to 33% each whereas the prevalence of these periodontal indicators was 38% and 44% respectively among smokeless tobacco users. Logistic regression analyses revealed that smokeless tobacco users were more liable for presence of periodontal pockets than smokers. Duration had a significant influence with users since more than 20 years being liable for presence of pockets at least twice (OR = 2.625, 95% CI 1.529 – 4.507) than the &lt;5 years group. The odds ratio for presence of periodontal pockets increased by 2.143 (95 % CI 1.060 – 4.333) and 5.596 (95 % CI 2.901 – 10.639) for users of 6 – 10 units/ day and more than 10 units/day than the 1-2 times/day category. Conclusions: Tobacco usage had a significant impact on the severity of periodontal disease with users being more likely to present periodontal pockets than non users. Moreover, the risk of periodontal pockets increased as the duration and frequency of tobacco consumption increased

Role of isoflavones and its derivatives on the growth of Pseudomonas putida and Escherichia coli

Two naturally occurring isoflavones genistine and biochanin - A, and their dihydro derivatives (isoflavones) as well as nine perhydroginated isoflavones (isoflavanes) were tested for their effects on mycelial growth of two soil bacteria viz., Pseudomonas putida and Escherichia coli. All the isoflavonenoids of the biochanin - A series showed the genistine isoflavane and the other isoflavanes with two hydroxyl groups and one methoxy groups are toxic, while isoflavones with two and one methoxy group were almost inactive. Genistein, a radio protective soy isoflavone and protein kinase inhibitor, blocks the invasion of pathogenic bacteria in mammalian epithelial cells. The purpose of this study was to evaluate the direct effect of genistein on the survival and growth of the probiotic Lactobacillus reuteri and selected opportunistic bacteria in vitro as a prelude to in vivo use for managing post irradiation sepsis. The opportunistic bacterial enteropathogens viz., Escherichia coli, Shigella sonnei, and Staphylococcus aureus as well as Klebsiella pneumoniae and the non-pathogenic organism, Bacillus anthracis (Sterne) were evaluated. The latter two bacteria are found in the environment and may be of concern in irradiated individuals. A standard in vitro test was employed to evaluate the direct effect of genistein on the bacteria