For photonic crystals (PhCs) and related devices, it is useful to calculate the Dirichlet-to-Neumann (DtN) map of a unit cell, which maps the wave field to its normal derivative on the boundary. The DtN map can be used to avoid further calculations in the interiors of the unit cells and formulate mathematical problems on the cell boundaries. We develop a method to approximate the DtN map for two-dimensional PhCs involving anisotropic media, and we calculate band structures for PhCs involving liquid crystals. For band structures of triangular lattice PhCs, we also develop new eigenvalue problem formulations involving smaller matrices.
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http://dx.doi.org/10.1364/josaa.26.001606 | DOI Listing |
Sensors (Basel)
August 2021
Department of Mathematics and Computer Science, Transilvania University of Brasov, 29 Eroilor Boulevard, 500036 Brasov, Romania.
Drones are frequently used for the delivery of materials or other goods, and to facilitate the capture and transmission of data. Moreover, drone networks have gained significant interest in a number of scenarios, such as in quarantined or isolated areas, following technical damage due to a disaster, or in non-urbanized areas without communication infrastructure. In this context, we propose a network of drones that are able to fly on a map covered by regular polygons, with a well-established mobility schedule, to carry and transfer data.
View Article and Find Full Text PDFSensors (Basel)
May 2021
Department of Mathematics and Computer Science, Transilvania University of Brasov, 29 Eroilor Boulevard, 500036 Brasov, Romania.
The communication in quarantined areas, e.g., due to the new COVID-19 pandemic, between isolated areas and in areas with technical damage has resulted in a great deal of interest concerning the safety of the population.
View Article and Find Full Text PDFFront Neurol
March 2021
Department of Industrial Engineering, Faculty of Engineering, Dalhousie University, Halifax, NS, Canada.
Stroke is a devastating disease, but it is treatable with alteplase or tissue plasminogen activator (tPA). The effectiveness of tPA is highly time-dependent, meaning rapid treatment is critical. Fast treatment with tPA has been reported in many urban hospitals, but hospitals in rural locations struggle to reduce treatment times.
View Article and Find Full Text PDFSensors (Basel)
January 2021
LASIGE, Departamento de Informática, Faculdade de Ciências da Universidade de Lisboa, 1749-016 Lisboa, Portugal.
Delay-tolerant networking (DTN) enables communication in disruptive scenarios where issues such as sparse and intermittent connectivity, long and variable delays, high latency, high error rates, or no end-to-end connectivity exist. Internet of Vehicles (IoV) is a network of the future in which integration between devices, vehicles, and users will be unlimited and universal, overcoming the heterogeneity of systems, services, applications, and devices. Delay-tolerant internet of vehicles (DT-IoV) is emerging and becoming a popular research topic due to the critical applications that can be realized, such as software or map update dissemination.
View Article and Find Full Text PDFBMJ Open Qual
July 2018
Department of Geriatric Medicine, University Hospital Limerick, Limerick, Ireland.
Background: In a busy stroke centre in Ireland, care for acute stroke was provided by a mixture of general physicians. In acute ischaemic stroke, speed is essential for good outcomes.
Aim: To improve acute stroke services and decrease door-to-needle (DTN) time to less than 60 min by December 2016 in patients with acute ischaemic stroke who are eligible for intravenous thrombolysis.
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