On Estimation of Maximum Errors for Inclinometric Systems with Fluxgate and Accelerometric Sensors

В статье рассматриваются вопросы построения инклинометрических систем с феррозондовыми и акселерометрическими датчиками, приводится структура инклинометрической системы и фотографии блоков двухосевых акселерометрических датчиков и трехкомпонентного феррозондового магнитометра. Рассматривается методика математического моделирования инклинометрических систем, основанная на формировании векторно-матричных уравнений и получении систем скалярных уравнений связи измеряемых проекций векторов ускорения свободного падения и индукции геомагнитного поля на оси чувствительности феррозондов и акселерометров. Приводятся базовые математические модели инклинометрических систем, позволяющие однозначное определение искомых угловых параметров пространственной ориентации по измеряемым сигналам с феррозондов и акселерометров. Получены общие аналитические выражения погрешностей измерений и выполнена оценка их предельных значений, позволяющая сформулировать требования к точности измеряемых сигналов в зависимости от предъявляемых требований в целом к метрологическим характеристикам инклинометрических систем. На основе анализа предельных значений погрешностей определения зенитного и визирного углов показана их зависимость от параметра наклона корпуса инклинометрической системы и от конкретных значений погрешностей измерений информационных сигналов с акселерометров. На основе анализа предельных значений погрешностей определения азимута показана их зависимость от угла магнитного наклонения и от конкретных значений погрешностей измерений информационных сигналов с феррозондов. Приведены графики зависимостей предельных значений погрешностей определения искомых углов.

METEOR: Online Seismic Metadata Builder

METEOR is an online tool dedicated to the generation of instrumental responses for seismological stations. This tool builds the complete response of the acquisition chain, while keeping the number of fields to be filled in very reduced. METEOR queries a very rich response databank, designed for the management of the French broadband seismological network (RESIF) and for many research projects involving velocimetric and accelerometric sensors over the last 20 yr. This tool is not intended to allow the management of metadata of an entire network, but to quickly build the instrumental responses of temporary stations. Information about the measuring instruments and their settings can be entered directly in the field, or later, back in the office. Instrument responses can be produced in the International Federation of Digital Seismograph Networks Station Extended Markup Language format (FDSN StationXML) and the metadata-only form of the Standard for Exchange of Earthquake Data (dataless SEED). METEOR is publicly available (see Data and Resources).

Accelerometric Trunk Sensors to Detect Changes of Body Positions in Immobile Patients

Mobilization, verticalization and position change are mandatory for severely affected neurological patients in early neurorehabilitation in order to improve neurological status and prevent complications. However, with the exception of hospitals and rehabilitation facilities, this activity is not usually monitored and so far the automated monitoring of position changes in immobile patients has not been investigated. Therefore, we investigated whether accelerometers on the upper trunk could reliably detect body position changes in immobile patients. Thirty immobile patients in early neurorehabilitation (Barthel Index ≤ 30) were enrolled. Two tri-axial accelerometers were placed on the upper trunk and on the thigh. Information on the position and position changes of the subject were derived from accelerometer data and compared to standard written documentation in the hospital over 24 h. Frequency and duration of different body positions (supine, sidelying, sitting) were measured. Data are presented as mean ± SEM. Groups were compared using one-way ANOVA or Kruskal-Wallis-test. Differences were considered significant if p < 0.05. Trunk sensors detected 100% and thigh sensors 66% of position changes (p = 0.0004) compared to standard care documentation. Furthermore, trunk recording also detected additional spontaneous body position changes that were not documented in standard care (81.8 ± 4.4% of all position changes were documented in standard care documentation) (p < 0.0001). We found that accelerometric trunk sensors are suitable for recording position changes and mobilization of severely affected patients. Our findings suggest that using accelerometers for care documentation is useful for monitoring position changes and mobilization frequencies in and outside of hospital for severely affected neurological patients. Accelerometric sensors may be valuable in monitoring continuation of care plans after intensive neurorehabilitation.

Site effect studies following the 2016 Mw 6.0 Amatrice Earthquake (Italy): the Emersito Task Force activities

<em>On August 24, 2016, at 01:36 UTC a M_W6.0 earthquake struck an extensive area of the Central Apennines (Italy). It was followed by a large aftershock (M_W5.3, August 24, 02:33 UTC) and about 20 earthquakes with magnitude greater than 4.0, located between the towns of Norcia and Amatrice. Due to the mainshock magnitude and the widespread damaging level of buildings in the epicentral area, the Emersito task force has been mobilized by the Istituto Nazionale di Geofisica e Vulcanologia (INGV). The aim of Emersito is to carry out and coordinate the monitoring of local site effects, caused by geological and geomorphological settings. During the first days of the seismic emergency, Emersito installed a temporary seismic network for site effect studies at 4 municipalities close to the epicentral area (Amandola, Civitella del Tronto, Montereale and Capitignano), using 22 stations equipped with both velocimetric and accelerometric sensors. The selection of the sites where stations have been installed was mainly driven by the proximity to the epicentral area (without interfere with the rescue operation) and by peculiar geologic and geomorphologic settings (topographic irregularities, fault zones, alluvial plains).</em>