Underwater Optical Wireless Communications Link for Short-Range Data Transmission: A Proof of Concept Study

Gemstone Team OPTICThe purpose of this thesis is to lay the groundwork for the development of a cost-effective Underwater Optical Wireless Communications system. Currently, one of the largest barriers to the expansion of underwater enterprise and research is a lack of high-speed wireless communication systems. Wireless communication underwater is essential for safety, improving aquatic technology, and many other marine ventures, yet it is still technologically limited. Current methods, such as acoustic communication, are often power inefficient, cumbersome, and expensive. The proposed system would enable scuba divers and researchers to bridge the technological gaps in available underwater data transmission systems. This paper proposes using visible light to wirelessly transmit data underwater. Visible light is an effective carrier wave underwater due to its large bandwidth and low absorption coefficient. Using light emitting diodes, silicon PIN photodetectors, waterproof enclosures, and consumer-grade microcontrollers, a model for the development of a wireless optical communications system is proposed. The system also adopts a modular design which allows each component to evolve as needed. The proposed system can transmit and receive audio and vitals signals underwater, illustrating the potential of a technology that could make diving and other underwater endeavors safer and more efficient. Furthermore, the proposed data link shows the potential for this technology to be used in other underwater applications that were previously limited by data speeds or mobility. Above all, this technology seeks to build upon existing knowledge of optical wireless communication and advance the field of underwater science and technology

Guidelines; from foe to friend? Comparative interviews with GPs in Norway and Denmark

<p>Abstract</p> <p>Background</p> <p>GPs follow clinical guidelines to varying degrees across practices, regions and countries, but a review study of GPs' attitudes to guidelines found no systematic variation in attitudes between studies from different countries. However, earlier qualitative studies on this topic are not necessarily comparable. Hence, there is a lack of empirical comparative studies of GP's attitudes to following clinical guidelines. In this study we reproduce a Norwegian focus group study of GPs' general attitudes to national clinical guidelines in Denmark and conduct a comparative analysis of the findings.</p> <p>Methods</p> <p>A strategic sample of GP's in Norway (27 GPs) and Denmark (18 GPs) was interviewed about their attitudes to guidelines, and the interviews coded and compared for common themes and differences.</p> <p>Results</p> <p>Similarities dominated the comparative material, but the analysis also revealed notable differences in attitudes between Norwegian and the Danish GPs. The most important difference was related to GP's attitudes to clinical guidelines that incorporated economic evaluations. While the Norwegian GPs were sceptical to guidelines that incorporated economic evaluation, the Danish GPs regarded these guidelines as important and legitimate. We suggest that the differences could be explained by the history of guideline development in Norway and Denmark respectively. Whereas government guidelines for rationing services were only newly introduced in Norway, they have been used in Denmark for many years.</p> <p>Conclusion</p> <p>Comparative qualitative studies of GPs attitudes to clinical guidelines may reveal cross-national differences relating to the varying histories of guideline development. Further studies are needed to explore this hypothesis.</p

Correction to: Cluster identification, selection, and description in Cluster randomized crossover trials: the PREP-IT trials

An amendment to this paper has been published and can be accessed via the original article