ABSTRACT
Corrections are given for errors in the presentation of equations in J. Opt. Soc. Am. A34, 1187 (2017)JOAOD60740-323210.1364/JOSAA.34.001187.
ABSTRACT
Underwater optical wireless communications (UOWC) performance is affected by turbulence. However, not much research has been carried out to estimate the probability density function (PDF) of the received optical power. In this paper, we investigate the effect of turbulence on the UOWC system using a new experimental setup with a variable link span in a water pool. Different turbulence levels are created by changing the temperature and the rate of an injected water flow in the pool water to obtain the PDF. Results show that lognormal distribution closely matches the measured PDF for a range of link spans. In UOWC systems, the link span is one of the main factors influencing fluctuations of the received optical power, and it has not been thoroughly investigated. In this work, the scintillation index and turbulence-induced power loss are obtained for a range of turbulence strengths and transmission link spans. Finally, we show that there is a good agreement between the experimental and simulated results.
ABSTRACT
Turbulence affects the performance of underwater wireless optical communications (UWOC). Although multiple scattering and absorption have been previously investigated by means of physical simulation models, still a physical simulation model is needed for UWOC with turbulence. In this paper, we propose a Monte Carlo simulation model for UWOC in turbulent oceanic clear water, which is far less computationally intensive than approaches based on computational fluid dynamics. The model is based on the variation of refractive index in a horizontal link. Results show that the proposed simulation model correctly reproduces lognormal probability density function of the received intensity for weak and moderate turbulence regimes. Results presented match well with experimental data reported for weak turbulence. Furthermore, scintillation index and turbulence-induced power loss versus link span are exhibited for different refractive index variations.
ABSTRACT
BACKGROUND: Asthma is caused by the combination of different factors. Current concepts of asthma pathogenesis emphasize on gene-environment interactions. Mega-genome scanning projects revealed that different Single Nucleotide Polymorphisms (SNPs) are related to asthma susceptibility. rs7216389-T is one of them that is related to childhood asthma and its effect on childhood asthma severity has been proved in different nations, however no study has been performed in Eastern Mediterranean and Middle East countries yet. METHODS: To perform population genetic studies, a rapid and high-throughput screening method is necessary. High-resolution melting analysis is a rapid, powerful and accurate method, which is suitable for this type of studies. Therefore, it has been decided to develop a high-resolution melting method for rs7216389 locus genotyping in Iranian asthmatic children. In the current study, a high-resolution melting analysis method based on SYBR Green-I was developed to check the frequency of rs7216389-T mutation in Iranian asthmatic children for the first time. RESULTS: Second and third classes of intercalating dyes are commonly used for high-resolution melting method. However, in this study, SYBR Green-I was used for rs7216389 locus genotyping for the first time. Our results for 60 samples showed that SYBR Green-I has good efficacy for rs7216389 locus genotyping through high-resolution melting method in comparison with PCR-RFLP and sequencing. CONCLUSION: Comparison of our results based on HRM analysis with PCR-RFLP showed that our developed method is rapid, accurate, high-throughput and economic to study the rs7216389 locus in asthmatic children and it is applicable for other similar population genetic studies.
