The scholar seismic network of Tenerife: technical and scientific issues

2020 ◽  
Author(s):  
Vidal Domínguez ◽  
José Barrancos ◽  
Luca D'Auria ◽  
Nemesio M. Peréz
Keyword(s):  
Canary Islands ◽  
Seismic Station ◽  
Low Cost ◽  
Seismic Network ◽  
Lower Sensitivity ◽  
Mems Sensors ◽  
Fully Integrated ◽  
Reduced Dimensions ◽  
Technological Advances ◽  
Didactic Material

<p>Currently thousands of seismic sensors, managed by different national and international institutions, are deployed throughout the planet. In the last decades, thanks to scientific and technological advances, broadband sensors are being produced at costs affordable for most institutions that operate a seismic network. At the same time, advances in nanotechnology led to the development of MEMS sensors which allowed the development of accelerometers of very reduced dimensions and low costs. The seismic data obtained by the commercial MEMS sensors, can be sampled, synchronized, stored and transmitted through low cost microcontrollers such as RaspberryPi or Arduino. This allows the development of a complete seismic station of very small size and cost with respect to the traditional ones, although of lower sensitivity and quality.</p><p>Since 2019, Instituto Volcanológico de Canaria (INVOLCAN) is developing a low cost seismic network: the <strong>Red Sísmica Escolar Canaria</strong> (<strong>RESECAN</strong>, <em>Scholar Canarian Seismic Network</em>) with multiple purposes. The main aims of RESECAN are:</p><ul><li>supporting the teaching of geosciences</li> <li>promoting the scientific vocation</li> <li>strengthening the resilience of the Canarian communities by improving awareness of the Canary volcanism and the associated hazards.</li> </ul><p>The project aims at realizing and distributing low-cost stations in various educational institutions of the Canary Islands, complementing them with didactic material on the topics of seismology and volcanology. Each school will be able to access the data of its own station, as well as other centers, being able to locate some of the recorded earthquakes. The data recorded by RESECAN will be fully integrated with the data of the Red Sísmica Canaria (C7), a permanent broadband seismic network operated by INVOLCAN. This will make RESECAN also an instrument of scientific interest able to contribute effectively to the volcanic monitoring of the Canary Islands, strengthening its resilience in facing future volcanic emergencies.</p>

scholarly journals Barriers to training in laparoscopic surgery in low- and middle-income countries: A systematic review

2021 ◽  
pp. 004947552199818
Author(s):  
Ellen Wilkinson ◽  
Noel Aruparayil ◽  
J Gnanaraj ◽  
Julia Brown ◽  
David Jayne
Keyword(s):  
Laparoscopic Surgery ◽  
Low Cost ◽  
Surgical Care ◽  
Successful Implementation ◽  
Middle Income ◽  
Middle Income Countries ◽  
Technological Advances ◽  
Local Access ◽  
And Training ◽  
Low And Middle Income

Laparoscopic surgery has the potential to improve care in resource-deprived low- and-middle-income countries (LMICs). This study aims to analyse the barriers to training in laparoscopic surgery in LMICs. Medline, Embase, Global Health and Web of Science were searched using ‘LMIC’, ‘Laparoscopy’ and ‘Training’. Two researchers screened results with mutual agreement. Included papers were in English, focused on abdominal laparoscopy and training in LMICs. PRISMA guidelines were followed; 2992 records were screened, and 86 full-text articles reviewed to give 26 key papers. Thematic grouping identified seven key barriers: funding; availability and maintenance of equipment; local access to experienced laparoscopic trainers; stakeholder dynamics; lack of knowledge on effective training curricula; surgical departmental structure and practical opportunities for trainees. In low-resource settings, technological advances may offer low-cost solutions in the successful implementation of laparoscopic training and improve access to surgical care.

scholarly journals In-Plane Monolithic Integration of Scaled III-V Photonic Devices

2021 ◽  
Vol 11 (4) ◽  
pp. 1887
Author(s):  
Markus Scherrer ◽  
Noelia Vico Triviño ◽  
Svenja Mauthe ◽  
Preksha Tiwari ◽  
Heinz Schmid ◽  
...  
Keyword(s):  
Integrated Circuits ◽  
High Speed ◽  
Low Cost ◽  
Photonic Devices ◽  
Monolithic Integration ◽  
Light Emitters ◽  
Fully Integrated ◽  
Large Lattice ◽  
Hybrid Iii ◽  
Gain Material

It is a long-standing goal to leverage silicon photonics through the combination of a low-cost advanced silicon platform with III-V-based active gain material. The monolithic integration of the III-V material is ultimately desirable for scalable integrated circuits but inherently challenging due to the large lattice and thermal mismatch with Si. Here, we briefly review different approaches to monolithic III-V integration while focusing on discussing the results achieved using an integration technique called template-assisted selective epitaxy (TASE), which provides some unique opportunities compared to existing state-of-the-art approaches. This method relies on the selective replacement of a prepatterned silicon structure with III-V material and thereby achieves the self-aligned in-plane monolithic integration of III-Vs on silicon. In our group, we have realized several embodiments of TASE for different applications; here, we will focus specifically on in-plane integrated photonic structures due to the ease with which these can be coupled to SOI waveguides and the inherent in-plane doping orientation, which is beneficial to waveguide-coupled architectures. In particular, we will discuss light emitters based on hybrid III-V/Si photonic crystal structures and high-speed InGaAs detectors, both covering the entire telecom wavelength spectral range. This opens a new path towards the realization of fully integrated, densely packed, and scalable photonic integrated circuits.

scholarly journals 60–700 K CTAT and PTAT Temperature Sensors with 4H-SiC Schottky Diodes

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 942
Author(s):  
Razvan Pascu ◽  
Gheorghe Pristavu ◽  
Gheorghe Brezeanu ◽  
Florin Draghici ◽  
Philippe Godignon ◽  
...  
Keyword(s):  
Low Cost ◽  
Schottky Diodes ◽  
Schottky Contact ◽  
High Sensitivity ◽  
Xrd Analysis ◽  
Absolute Temperature ◽  
Lower Sensitivity ◽  
Readout Circuit ◽  
Sensing Element ◽  
High Performing

A SiC Schottky dual-diode temperature-sensing element, suitable for both complementary variation of VF with absolute temperature (CTAT) and differential proportional to absolute temperature (PTAT) sensors, is demonstrated over 60–700 K, currently the widest range reported. The structure’s layout places the two identical diodes in close, symmetrical proximity. A stable and high-barrier Schottky contact based on Ni, annealed at 750 °C, is used. XRD analysis evinced the even distribution of Ni2Si over the entire Schottky contact area. Forward measurements in the 60–700 K range indicate nearly identical characteristics for the dual-diodes, with only minor inhomogeneity. Our parallel diode (p-diode) model is used to parameterize experimental curves and evaluate sensing performances over this far-reaching domain. High sensitivity, upwards of 2.32 mV/K, is obtained, with satisfactory linearity (R2 reaching 99.80%) for the CTAT sensor, even down to 60 K. The PTAT differential version boasts increased linearity, up to 99.95%. The lower sensitivity is, in this case, compensated by using a high-performing, low-cost readout circuit, leading to a peak 14.91 mV/K, without influencing linearity.

scholarly journals A DCM Based Attitude Estimation Algorithm for Low-Cost MEMS IMUs

2015 ◽  
Vol 2015 ◽  
pp. 1-18 ◽  
Author(s):  
Heikki Hyyti ◽  
Arto Visala
Keyword(s):  
Kalman Filter ◽  
Extended Kalman Filter ◽  
Low Cost ◽  
Direction Cosine ◽  
Estimation Algorithm ◽  
Calibration Method ◽  
Attitude Estimation ◽  
Mems Sensors ◽  
Acceleration Sensors ◽  
Adaptive Extended Kalman Filter

An attitude estimation algorithm is developed using an adaptive extended Kalman filter for low-cost microelectromechanical-system (MEMS) triaxial accelerometers and gyroscopes, that is, inertial measurement units (IMUs). Although these MEMS sensors are relatively cheap, they give more inaccurate measurements than conventional high-quality gyroscopes and accelerometers. To be able to use these low-cost MEMS sensors with precision in all situations, a novel attitude estimation algorithm is proposed for fusing triaxial gyroscope and accelerometer measurements. An extended Kalman filter is implemented to estimate attitude in direction cosine matrix (DCM) formation and to calibrate gyroscope biases online. We use a variable measurement covariance for acceleration measurements to ensure robustness against temporary nongravitational accelerations, which usually induce errors when estimating attitude with ordinary algorithms. The proposed algorithm enables accurate gyroscope online calibration by using only a triaxial gyroscope and accelerometer. It outperforms comparable state-of-the-art algorithms in those cases when there are either biases in the gyroscope measurements or large temporary nongravitational accelerations present. A low-cost, temperature-based calibration method is also discussed for initially calibrating gyroscope and acceleration sensors. An open source implementation of the algorithm is also available.

A self-developed indoor three-dimensional pedestrian localization platform based on MEMS sensors

Sensor Review ◽  
2015 ◽  
Vol 35 (2) ◽  
pp. 157-167 ◽  
Author(s):  
Shengbo Sang ◽  
Ruiyong Zhai ◽  
Wendong Zhang ◽  
Qirui Sun ◽  
Zhaoying Zhou
Keyword(s):  
Low Cost ◽  
Angular Rate ◽  
Three Dimensional ◽  
Dead Reckoning ◽  
Rate Data ◽  
Mems Sensors ◽  
Micro Electro Mechanical Systems ◽  
Content Type ◽  
Position Errors ◽  
Low Performance

Purpose – This study aims to design a new low-cost localization platform for estimating the location and orientation of a pedestrian in a building. The micro-electro-mechanical systems (MEMS) sensor error compensation and the algorithm were improved to realize the localization and altitude accuracy. Design/methodology/approach – The platform hardware was designed with common low-performance and inexpensive MEMS sensors, and with a barometric altimeter employed to augment altitude measurement. The inertial navigation system (INS) – extended Kalman filter (EKF) – zero-velocity updating (ZUPT) (INS-EKF-ZUPT [IEZ])-extended methods and pedestrian dead reckoning (PDR) (IEZ + PDR) algorithm were modified and improved with altitude determined by acceleration integration height and pressure altitude. The “AND” logic with acceleration and angular rate data were presented to update the stance phases. Findings – The new platform was tested in real three-dimensional (3D) in-building scenarios, achieved with position errors below 0.5 m for 50-m-long route in corridor and below 0.1 m on stairs. The algorithm is robust enough for both the walking motion and the fast dynamic motion. Originality/value – The paper presents a new self-developed, integrated platform. The IEZ-extended methods, the modified PDR (IEZ + PDR) algorithm and “AND” logic with acceleration and angular rate data can improve the high localization and altitude accuracy. It is a great support for the increasing 3D location demand in indoor cases for universal application with ordinary sensors.

scholarly journals Global positioning system resurvey of Southern California Seismic Network stations

1995 ◽  
Vol 85 (1) ◽  
pp. 361-374
Author(s):  
Jennifer S. Haase ◽  
Egill Hauksson ◽  
Hiroo Kanamori ◽  
Jim Mori
Keyword(s):  
Global Positioning System ◽  
Southern California ◽  
Seismic Station ◽  
Seismic Network ◽  
Positioning System ◽  
Dual Frequency ◽  
Time Data ◽  
Phase Measurements ◽  
Station Coordinates ◽  
Global Positioning

Abstract Systematic errors in travel-time data from local earthquakes can sometimes be traced to inaccuracies in the published seismic station coordinates. This prompted a resurvey of the stations of the Caltech/USGS Southern California Seismic Network (SCSN) using the Global Positioning System (GPS). We surveyed 241 stations of the SCSN using Trimble and Ashtech dual-frequency GPS receivers and calculated positions accurate to 3 m using differential positioning from carrier phase measurements. Twelve percent of the stations that were surveyed were found to be mislocated by more than 500 m. Stations of the TERRAscope and USC networks were also surveyed, as well as a network of portable seismic stations deployed shortly after the 1992 Joshua Tree and Landers earthquakes. The new coordinates and the offsets from the old coordinates are given below. The new coordinates are being used in SCSN locations as of 1 January 1994.

scholarly journals Cone-Beam Three-Dimensional Dental Volumetric Tomography in Dental Practice

2017 ◽  
Vol 7 (3) ◽  
pp. 62 ◽  
Author(s):  
Suzan Cangul ◽  
Ozkan Adiguzel
Keyword(s):  
Soft Tissues ◽  
Low Cost ◽  
Three Dimensional ◽  
Cone Beam ◽  
Imaging Method ◽  
Dental Practice ◽  
3 Dimensional ◽  
Scanning Time ◽  
Technological Advances ◽  
Native Speakers Of English

Imaging methods are of great importance for diagnosis and treatment in dentistry. With technological advances, great progress has been made in these methods. Over time, 3-dimensional (3-D) imaging has replaced 2-dimensional, thereby providing examination of objects in all directions. Of these methods, which play an important role in the clinical evaluation of patients, cone-beam computed tomography (CBCT) is the newest and most advanced imaging method. This method will revolutionize dental in comparison with conventional CT, it has several advantages, including a shorter scanning time, low radiation dose, low cost and the acquisition of high-resolution images. With 3-D imaging technology, this method has introduced the possibility of applying several procedures from diagnosis in the maxillofacial region to operative and surgical procedures. Although very clear results are not obtained from the imaging of soft tissues, the most important advantage of this technology is the capability of imaging hard and soft tissues together.   How to cite this article: Cangul S, Adiguzel O. Cone-Beam Three-Dimensional Dental Volumetric Tomography in Dental Practice. Int Dent Res 2017;7:62-70.  Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

scholarly journals Ethical Issues in Global Supply Chains

2007 ◽  
Author(s):  
Bodo B. Schlegelmilch ◽  
Magdalena Öberseder
Keyword(s):  
Supply Chain ◽  
Supply Chains ◽  
Working Conditions ◽  
Ethical Issues ◽  
Low Cost ◽  
Global Supply Chains ◽  
Unethical Conduct ◽  
Production Methods ◽  
Technological Advances ◽  
Consumer Demands

Despite all technological advances, global supply chains are always based on the interaction of people. And wherever people interact, a kaleidoscope of ethical issues emerges. While consumer demands and concerns have undoubtedly led to an increased awareness of unethical conduct in the supply chain, contravening forces, such as the relentless pressures for low cost products and the ease by which consumers are purchasing non-deceptive counterfeits, should also not be ignored. Many retailers are now embracing ethical issues by emphasising, for example, that they take care of the production methods and working conditions pertaining to the goods they offer.

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