Submillimetric GPS distance measurement over short baselines: noise mitigation by global robust estimation

The potential use of GPS technology for precise length determination is currently a topic of extensive research. A prior work was dedicated to submillimetric length determination over short baselines and under ideal conditions of data availability and a clear environment. This paper presents a new computation method suited to the less favourable working conditions that are usually encountered in practice. It is based on both robust estimation theory and the use of an ambiguity-free estimation method. As the experimental comparisons with the standard procedure based on least-squares ambiguity determination show, it provides more stable values and permits results to be obtained significant to the submillimetre level with time spans of a few hours.This research is funded by the Spanish Ministry of Science and Innovation (AYA2011-23232).Baselga Moreno, S.; García-Asenjo Villamayor, L.; Garrigues Talens, P. (2014). Submillimetric GPS distance measurement over short baselines: noise mitigation by global robust estimation. Measurement Science and Technology. 25(10):1-6. https://doi.org/10.1088/0957-0233/25/10/105004S162510Altamimi, Z., Collilieux, X., & Métivier, L. (2011). ITRF2008: an improved solution of the international terrestrial reference frame. Journal of Geodesy, 85(8), 457-473. doi:10.1007/s00190-011-0444-4Amiri-Simkooei, A. R., & Tiberius, C. C. J. M. (2006). Assessing receiver noise using GPS short baseline time series. GPS Solutions, 11(1), 21-35. doi:10.1007/s10291-006-0026-8Baire, Q., Bruyninx, C., Legrand, J., Pottiaux, E., Aerts, W., Defraigne, P., … Chevalier, J. M. (2013). Influence of different GPS receiver antenna calibration models on geodetic positioning. GPS Solutions, 18(4), 529-539. doi:10.1007/s10291-013-0349-1Baselga, S. (2007). Global Optimization Solution of Robust Estimation. Journal of Surveying Engineering, 133(3), 123-128. doi:10.1061/(asce)0733-9453(2007)133:3(123)Baselga, S. (2010). Global optimization applied to GPS positioning by ambiguity functions. Measurement Science and Technology, 21(12), 125102. doi:10.1088/0957-0233/21/12/125102Baselga, S. (2014). Ambiguity-Free Method for Fast and Precise GNSS Differential Positioning. Journal of Surveying Engineering, 140(1), 22-27. doi:10.1061/(asce)su.1943-5428.0000111Baselga, S., & García-Asenjo, L. (2008). GNSS Differential Positioning by Robust Estimation. Journal of Surveying Engineering, 134(1), 21-25. doi:10.1061/(asce)0733-9453(2008)134:1(21)Baselga, S., & García-Asenjo, L. (2008). Multipath Mitigation by Global Robust Estimation. Journal of Navigation, 61(3), 385-392. doi:10.1017/s0373463308004803Baselga, S., García-Asenjo, L., & Garrigues, P. (2013). Submillimetric GPS distance measurement over short baselines: case study in inner consistency. Measurement Science and Technology, 24(7), 075001. doi:10.1088/0957-0233/24/7/075001Dow, J. M., Neilan, R. E., & Rizos, C. (2009). The International GNSS Service in a changing landscape of Global Navigation Satellite Systems. Journal of Geodesy, 83(3-4), 191-198. doi:10.1007/s00190-008-0300-3Griffiths, J., & Ray, J. R. (2012). Sub-daily alias and draconitic errors in the IGS orbits. GPS Solutions, 17(3), 413-422. doi:10.1007/s10291-012-0289-1Huber, P. J. (1981). Robust Statistics. Wiley Series in Probability and Statistics. doi:10.1002/0471725250Koivula, H., Häkli, P., Jokela, J., Buga, A., & Putrimas, R. (2011). GPS Metrology: Bringing Traceable Scale to a Local Crustal Deformation GPS Network. International Association of Geodesy Symposia, 105-112. doi:10.1007/978-3-642-20338-1_13Niu, X., Chen, Q., Zhang, Q., Zhang, H., Niu, J., Chen, K., … Liu, J. (2013). Using Allan variance to analyze the error characteristics of GNSS positioning. GPS Solutions, 18(2), 231-242. doi:10.1007/s10291-013-0324-xRay, J., Altamimi, Z., Collilieux, X., & van Dam, T. (2007). Anomalous harmonics in the spectra of GPS position estimates. GPS Solutions, 12(1), 55-64. doi:10.1007/s10291-007-0067-7Snay, R. A., & Soler, T. (2008). Continuously Operating Reference Station (CORS): History, Applications, and Future Enhancements. Journal of Surveying Engineering, 134(4), 95-104. doi:10.1061/(asce)0733-9453(2008)134:4(95)Wieser, A., & Brunner, F. K. (2002). Short Static GPS Sessions: Robust Estimation Results. GPS Solutions, 5(3), 70-79. doi:10.1007/pl00012901Yang, Y. (1999). Robust estimation of geodetic datum transformation. Journal of Geodesy, 73(5), 268-274. doi:10.1007/s001900050243Yang, Y., Song, L., & Xu, T. (2002). Robust estimator for correlated observations based on bifactor equivalent weights. Journal of Geodesy, 76(6-7), 353-358. doi:10.1007/s00190-002-0256-

Fluorescence probe-label methodology for in situ monitoring network forming reactions

The curing of the stoichiometric reaction mixture diglycidyl ether bisphenol A (DGEBA) with N-methylethylenediamine (MEDA) and BEPOX 1268 formulation was monitored by FTIR (in the near IR region) and by fluorescence spectroscopy. 5-Dimethylamino-1-naphthalenesulfonamide derivatives and 4-dialkylamino-4′-nitrostilbene structural units were used as labels and/or probes. It has been proved that hardener in BEPOX 1268 formulation consists of amine containing the primary and secondary amino group. The rate constant for the addition reaction of the secondary amino hydrogen to epoxide is approximately two times larger than that of the primary amino group hydrogen in MEDA and several times (∼seven times) lower in the amine component of BEPOX 1268 formulation. The changes in the integrated fluorescence intensity of the label during the epoxy groups conversion indicate the most important changes in chemical transformations of the reaction mixture, i.e. primary reaction of the secondary amino groups, the gel point (DGEBA–MEDA) and entry of the system to the glassy state (for DGEBA–MEDA and BEPOX 1268). The change in slope of the fluorescence half bandwidth dependence on the epoxy groups conversion indicates the maximum concentration of the secondary amino groups in the reaction mixture (BEPOX 1268). It has been shown that the dependence of the first moment of the emission band vs. epoxy groups conversion can be used to determine the epoxy groups conversion in situ and in real time.The authors would like to thank for funding to the European Commission through the BRITE-EuRam project (no. BE97-4472) and to CAM (projects 07N/0002/98 and 3rd Regional Research Programme)

Submicronic Filtering Media Based on Electrospun Recycled PET Nanofibers: Development, Characterization, and Method to Manufacture Surgical Masks

The disposal of single-use personal protective equipment has brought a notable environmental impact in the context of the COVID-19 pandemic. During these last two years, part of the global research efforts has been focused on preventing contagion using nanotechnology. This work explores the production of filter materials with electrohydrodynamic techniques using recycled polyethylene terephthalate (PET). PET was chosen because it is one of the materials most commonly present in everyday waste (such as in food packaging, bags, or bottles), being the most frequently used thermoplastic polymer in the world. The influence of the electrospinning parameters on the filtering capacity of the resulting fabric was analyzed against both aerosolized submicron particles and microparticulated matter. Finally, we present a new scalable and straightforward method for manufacturing surgical masks by electrospinning and we validate their performance by simulating the standard conditions to which they are subjected to during use. The masks were successfully reprocessed to ensure that the proposed method is able to reduce the environmental impact of disposable face masks. © 2022 by the authors. Licensee MDPI, Basel, Switzerland

Application of median-equation approach for outlier detection in geodetic networks

In geodetic measurements some outliers may occur sometimes in data sets, depending on different reasons. There are two main approaches to detect outliers as Tests for outliers (Baarda's and Pope's Tests) and robust methods (Danish method, Huber method etc.). These methods use the Least Squares Estimation (LSE). The outliers affect the LSE results, especially it smears the effects of the outliers on the good observations and sometimes wrong results may be obtained. To avoid these effects, a method that does not use LSE should be preferred. The median is a high breakdown point estimator and if it is applied for the outlier detection, reliable results can be obtained. In this study, a robust method which uses median with or as a treshould value on median residuals that are obtained from median equations is proposed. If the a priori variance of the observations is known, the reliability of the new approch is greater than the one in the case where the a priori variance is unknown

Recent Technological Developments on LGAD and iLGAD Detectors for Tracking and Timing Applications

This paper reports the last technological development on the Low Gain Avalanche Detector (LGAD) and introduces a new architecture of these detectors called inverse-LGAD (iLGAD). Both approaches are based on the standard Avalanche Photo Diodes (APD) concept, commonly used in optical and X-ray detection applications, including an internal multiplication of the charge generated by radiation. The multiplication is inherent to the basic n++-p+-p structure, where the doping profile of the p+ layer is optimized to achieve high field and high impact ionization at the junction. The LGAD structures are optimized for applications such as tracking or timing detectors for high energy physics experiments or medical applications where time resolution lower than 30 ps is required. Detailed TCAD device simulations together with the electrical and charge collection measurements are presented through this work.Comment: Keywords: silicon detectors, avalanche multiplication, timing detectors, tracking detectors. 8 pages. 8 Figure

Incidence and time course of everolimus-related adverse events in postmenopausal women with hormone receptor-positive advanced breast cancer: insights from BOLERO-2.

BackgroundIn the BOLERO-2 trial, everolimus (EVE), an inhibitor of mammalian target of rapamycin, demonstrated significant clinical benefit with an acceptable safety profile when administered with exemestane (EXE) in postmenopausal women with hormone receptor-positive (HR(+)) advanced breast cancer. We report on the incidence, time course, severity, and resolution of treatment-emergent adverse events (AEs) as well as incidence of dose modifications during the extended follow-up of this study.Patients and methodsPatients were randomized (2:1) to receive EVE 10 mg/day or placebo (PBO), with open-label EXE 25 mg/day (n = 724). The primary end point was progression-free survival. Secondary end points included overall survival, objective response rate, and safety. Safety evaluations included recording of AEs, laboratory values, dose interruptions/adjustments, and study drug discontinuations.ResultsThe safety population comprised 720 patients (EVE + EXE, 482; PBO + EXE, 238). The median follow-up was 18 months. Class-effect toxicities, including stomatitis, pneumonitis, and hyperglycemia, were generally of mild or moderate severity and occurred relatively early after treatment initiation (except pneumonitis); incidence tapered off thereafter. EVE dose reduction and interruption (360 and 705 events, respectively) required for AE management were independent of patient age. The median duration of dose interruption was 7 days. Discontinuation of both study drugs because of AEs was higher with EVE + EXE (9%) versus PBO + EXE (3%).ConclusionsMost EVE-associated AEs occur soon after initiation of therapy, are typically of mild or moderate severity, and are generally manageable with dose reduction and interruption. Discontinuation due to toxicity was uncommon. Understanding the time course of class-effect AEs will help inform preventive and monitoring strategies as well as patient education.Trial registration numberNCT00863655