Underwater Optical Wireless Communication (UOWC) is not a new idea, but it has recently attracted renewed interest since seawater presents a reduced absorption window for blue-green light. Due to its higher bandwidth, underwater optical wireless communications can support higher data rates at low latency levels compared to acoustic and RF counterparts. The paper is aimed at those who want to undertake studies on UOWC. It offers an overview on the current technologies and those potentially available soon. Particular attention has been given to offering a recent bibliography, especially on the use of single-photon receivers.
A new acquisition system for remote control of wall paintings has been realized and tested in the field. The system measures temperature and atmospheric pressure in an archeological site where a fresco has been put under control. The measuring chain has been designed to be used in unfavorable environments where neither electric power nor telecommunication infrastructures are available. The environmental parameters obtained from the local monitoring are then transferred remotely allowing an easier management by experts in the field of conservation of cultural heritage. The local acquisition system uses an electronic card based on microcontrollers and sends the data to a central unit realized with a Raspberry-Pi. The latter manages a high quality camera to pick up pictures of the fresco. Finally, to realize the remote control at a site not reached by internet signals, a WiMAX connection based on different communication technologies such as WiMAX, Ethernet, GPRS and Satellite, has been set up.
Banknote security is an issue that has led in the last decades to insert, inside the banknote itself, a very high number of controlling methods with the aim of verifying possible tampering attempts. In order to distinguish the false banknotes, sophisticated means (i.e. watermark, feel of the paper, raised print, metallic threads, quality of the printing, holograms, ultraviolet features, micro-lettering, etc) are often used. The purpose of this paper is to show a new approach and related method to protect banknotes and to verify their originality, based on the idea of hylemetry (methodology conceptually similar to biometry) applied to banknotes. Specifically, the hylemetric feature used in this paper is the random distribution pattern of the metallic security fibers set into the paper pulp. The outcome of the proposed solution is to identify an original banknote using a binary sequence derived from the banknote itself.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.