In-field Validation Research Articles

In-Field Validation of an Inertial Sensor-Based System for Movement Analysis and Classification in Ski Mountaineering.

Ski Mountaineering (SkiMo) is a fast growing sport requiring both endurance and technical skills. It involves different types of locomotion with and without the skis. The aim of this study is to develop and validate in the snowfield a novel inertial-based system for analysing cycle parameters and classifying movement in SkiMo in real-time. The study was divided into two parts, one focused on real-time parameters estimation (cadence, distance from strides, stride duration, stride length, number of strides, slope gradient, and power) and, second, on transition detection (kickturns, skin on, skin off, ski on and off backpack) in order to classify between the different types of locomotion. Experimental protocol involved 16 experienced subjects who performed different SkiMo trials with their own equipment instrumented with a ski-mounted inertial sensor. The results obtained by the algorithm showed precise results with a relative error near 5% on all parameters. The developed system can, therefore, be used by skiers to obtain quantitative training data analysis and real-time feedback in the field. Nevertheless, a deeper validation of this algorithm might be necessary in order to confirm the accuracy on a wider population of subjects with various skill levels.

Dragonfly: A multi-platform parallel toolbox for MATLAB/Octave

In this paper, we present Dragonfly, a free open-source software toolkit that allows creating a parallel collaboration environment between MATLAB and/or Octave instances, allowing us to have a robust system, which is flexible, transparent and interoperable. Dragonfly can be used under multi-platform (Linux, Windows, Mac) and multi-environment configurations (e.g., MATLAB and/or Octave instances). To distribute the workload, it has a flexible system, where programmers can select the computational resources, create clusters and assign weights to balance properly tasks across the distributed environment (MATLAB and Octave instances machines) with different computational power. These functionalities allow obtaining good performance metrics such as: execution time, scalability and efficiency. Finally, this tool has been tested on different computer systems from standard commodity environments to medium size clusters using a set of applications from different scientific fields. This widespread in-field validation allowed showing good performances not only in speedup but also in efficiency using Dragonfly.

Development and implementation of a pass/fail field-friendly method for detecting sildenafil in suspect pharmaceutical tablets using a handheld Raman spectrometer and silver colloids

A simple, fast, sensitive and effective pass/fail field-friendly method has been developed for detecting sildenafil in suspect Viagra and unapproved tablets using handheld Raman spectrometers and silver colloids. The method involves dissolving a portion of a tablet in water followed by filtration and addition of silver colloids, resulting in a solution that can be measured directly through a glass vial. Over one hundred counterfeit Viagra and unapproved tablets were examined on three different devices during the method development phase of the study. While the pass/fail approach was found to be 92.6% effective on average, the efficacy increased to 97.4% on average when coupled with the software’s “Discover Mode” feature that allows the user to compare a suspect spectrum to that of a stored sildenafil spectrum. The lowest concentration of sildenafil in a water/colloid solution that yielded a “Pass” was found to be 7.6μg/mL or 7.6 parts per million (ppm). For the analysis of suspect tablets, this value was found to be as low as 10μg/mL and as high as 625μg/mL. This variability was likely related to the tablet formulation, e.g., concentration of sildenafil, presence and concentration of water-soluble and/or water-insoluble ingredients. However, since most counterfeit Viagra and unapproved tablets contain >50mg sildenafil per tablet, such low concentrations will not be encountered often. Limited in-lab and in-field validation studies were conducted in which analysts/field agents followed the procedure outlined in this study for small sample sets. These individuals were provided with written instructions, a ∼20min demonstration regarding how to perform the procedure and use the instrument, and a kit with field-friendly supplies (purified bottled water from a local grocery store, disposable plastic pipettes, eye-dropper with a silver colloid solution, etc.). The method proved to be 98.3% and 91.7% effective for the in-lab and in-field validation studies, respectively, which demonstrated the ruggedness, simplicity and practicality of the method.

Development of a 4 MW Full-Size Wind-Turbine Test Bench

The in-field validation of wind turbines (WTs) behavior is very time consuming and cost intensive, especially when fault ride-through tests are conducted. Full-size wind-turbine test benches allow a realistic operation of WTs in an artificial environment. Due to the independency of wind and grid conditions, the cost and duration of the test program and certification can be reduced. This paper presents the development of 4 MW full-size wind-turbine test bench following a multiphysics power hardware-in-the-loop concept. Different from other test facilities, the presented test bench utilizes a direct-drive prime-mover concept combined with a nontorque-load (NTL) unit to enable the application of highly dynamic stresses at the rotor hub and additionally a power-electronics-based grid emulator. Through the measurement results of the test programs conducted on the test bench, the capability of the test bench in replicating the field conditions including voltage dips is demonstrated. In addition, a time consuming efficiency measurement can be performed with the reduced duration on the test bench. This shows another main benefit of the test bench compared to the conventional test method for WTs.

Determining fPAR and leaf area index of several land cover classes in the Pot River and Tsitsa River catchments of the Eastern Cape, South Africa

Determining the quantum (both annual maxima and minima) and the temporal variation in the leaf area index (LAI), and the fraction of photosynthetically active radiation (fPAR), are three fundamental biophysical characteristics of the plant canopy that should parameterise ecophysiological models of water use (evapotranspiration) and carbon sequestration. Although Earth observation provides values and time series for both these parameters, in-field validation of these values is necessary. Following a very wet summer season, we conducted field surveys of several land cover classes within two quaternary catchments in the Eastern Cape province, South Africa, to determine maximum values of LAI and fPAR that occur within each of these land cover classes. To assist in up-scaling these point measures to the landscape, we present a regression relationship between Landsat 8 NDVI and LAI measured using an Accupar Ceptometer (r2 = 0.92). Peak wet season LAI varied from extremely high (>7.0) under the canopy of invasive black wattle (Acacia mearnsii) trees to ∼2.0 under the canopy of a Eucalyptus plantation. Ungrazed native grassland displayed an intermediate LAI value of 3.84. The black wattle stand absorbed 97% of the available PAR, whereas the mature Eucalyptus plantation only absorbed 66% of PAR.

The Influence of Head Impact Threshold for Reporting Data in Contact and Collision Sports: Systematic Review and Original Data Analysis.

Head impacts and resulting head accelerations cause concussive injuries. There is no standard for reporting head impact data in sports to enable comparison between studies. The aim was to outline methods for reporting head impact acceleration data in sport and the effect of the acceleration thresholds on the number of impacts reported. A systematic review of accelerometer systems utilised to report head impact data in sport was conducted. The effect of using different thresholds on a set of impact data from 38 amateur senior rugby players in New Zealand over a competition season was calculated. Of the 52 studies identified, 42% reported impacts using a >10-g threshold, where g is the acceleration of gravity. Studies reported descriptive statistics as mean ± standard deviation, median, 25th to 75th interquartile range, and 95th percentile. Application of the varied impact thresholds to the New Zealand data set resulted in 20,687 impacts of >10 g, 11,459 (45% less) impacts of >15 g, and 4024 (81% less) impacts of >30 g. Linear and angular raw data were most frequently reported. Metrics combining raw data may be more useful; however, validity of the metrics has not been adequately addressed for sport. Differing data collection methods and descriptive statistics for reporting head impacts in sports limit inter-study comparisons. Consensus on data analysis methods for sports impact assessment is needed, including thresholds. Based on the available data, the 10-g threshold is the most commonly reported impact threshold and should be reported as the median with 25th and 75th interquartile ranges as the data are non-normally distributed. Validation studies are required to determine the best threshold and metrics for impact acceleration data collection in sport. Until in-field validation studies are completed, it is recommended that head impact data should be reported as median and interquartile ranges using the 10-g impact threshold.

The assessment of dust drift from pneumatic drills using static tests and in-field validation

The utilization of dressed seed for sowing is a widespread practice to control certain pests with reduced doses of chemical products. The pneumatic drills used in maize (Zea mays L.) sowing have been shown to contribute to the dispersion of the abrasion dust produced by dressed seeds, causing environmental contamination. In recent years, several insecticides (neonicotinoids and fipronil) employed for maize dressing have been claimed to cause mortality and sub-lethal effects to honey bees (Apis mellifera L.). This paper reports a two-stage research study aimed at evaluating the amounts of dust emitted by a precision pneumatic drill during the sowing of maize dressed with clothianidin, fipronil, imidacloprid and thiamethoxam. In the first step, we assessed the dust drift in static tests performed in a simulated wind tunnel. Next, we compared the results with real sowing trials carried out in the field. The data were subjected to appropriate processing that provided a theoretical assessment of the spatial distribution of the pesticide concentration. The results demonstrated a good correspondence between the amounts of predicted drift at ground level during the static tests and the measured residues during the field trials. At the same time, no prediction was possible in terms of air concentrations of the active ingredient, suggesting that the dust drift in the air behaves differently from its deposition on the ground.

Design and implementation of a new autonomous sensor fish to support advanced hydropower development.

Acceleration in development of additional conventional hydropower requires tools and methods to perform laboratory and in-field validation of turbine performance and fish passage claims. The new-generation Sensor Fish has been developed with more capabilities to accommodate a wider range of users over a broader range of turbine designs and operating environments. It provides in situ measurements of three-dimensional (3D) linear accelerations, 3D rotational velocities, 3D orientation, pressure, and temperature at a sampling frequency of 2048 Hz. It also has an automatic floatation system and built-in radio-frequency transmitter for recovery. The relative errors of the pressure, acceleration, and rotational velocity were within ±2%, ±5%, and ±5%, respectively. The accuracy of orientation was within ±4° and accuracy of temperature was ±2 °C. The new-generation Sensor Fish is becoming a major technology and being deployed for evaluating the conditions for fish passage of turbines or other hydraulic structures in both the United States and several other countries.

Cooperative Autonomous Robotic Towing system: definition of requirements and operating scenarios

The project CART (Cooperative Autonomous Robotic Towing system) proposes a new concept for salvage operations of distressed ships at sea based on the development of robotised unmanned marine platforms able to (semi-)automatically execute the high risk operation of linking the emergency towing system of distressed ships to towing vessels. The CART device will be able to optimize the operations for safeguarding the environment, helping to prevent oil pollution at sea, and minimizing the risk for human lives. This paper presents user requirements and operating scenarios for the development of a prototype system able to support the in-field validation of the proposed concept.

Paramedic Identification of Stroke: Community Validation of the Melbourne Ambulance Stroke Screen

Background: Paramedics require an effective prehospital tool to eliminate stroke mimics and to assist in the identification of suitable candidates for thrombolytic therapy. The Faster Access to Stroke Therapies study combined two validated stroke assessment tools (the Los Angeles Prehospital Stroke Screen, LAPSS, and the Cincinnati Prehospital Stroke Scale, CPSS) to form the Melbourne Ambulance Stroke Screen (MASS), and performed an in-field validation by Australian paramedics. Methods: Over a 12-month period, 18 paramedics participated in the Faster Access to Stroke Therapies study and prospectively collected data contained in the MASS on all stroke dispatches, and for other patients with a focal neurological deficit. Sensitivity and specificity analysis of the LAPSS, CPSS and MASS was calculated and equivalence analysis performed. Results: Paramedics completed 100 MASS assessments for 73 (73%) stroke/transient ischemic attack patients and 27 (27%) stroke mimics. The sensitivity of the MASS (90%, 95% CI: 81–96%) showed statistical equivalence to the sensitivity of the CPSS (95%, p = 0.45) and superiority to the LAPSS (78%, p = 0.008). The specificity of the MASS (74%, 95% CI: 53–88%) was equivalent to that of the LAPSS (85%, p = 0.25) and superior to the CPSS (54%, p = 0.007). All patients misidentified by the MASS (7 strokes, 7 mimics) were ineligible for thrombolytic therapy. Conclusion: The MASS is simple to use, with accurate prehospital identification of stroke. It distinguishes stroke mimics, with good recognition of suitable patients for thrombolytic therapy.

Laboratory Calibration, In-Field Validation and Use of a Soil Penetrometer Measuring Cone Resistance and Water Content

Concurrent and coincident measure of penetrometer cone resistance (PR) and water content (WC) were optimized by hourly in-field validation of data from time domain transmissiometry (TDT) for WC and piezoelectric force sensor for PR. A piezoelectric force sensor coupled to a cone is followed by a helical wrapped TDT sensor on a single penetrometer shaft. Detailed laboratory calibrations, coupled with in-field validations, were important to assure the quality of data, which facilitated detailed analyses of PR and WC patterns. The piezoelectric sensor relied on a calibrated spring for the in-field validation. The calibration of the TDT sensor had three stages: a series of fluids of known dielectric constant; soil columns at known, variable water contents; and field soils at a range of ambient conditions. The penetrometer was used to study soil strength and WC behavior in time and space along 300-m plots. The treatments were conventional and no-till, each at two levels of traffic. The crop was corn (Zea mays L.), continuous and in rotation with soybean [Glycine max (L.) Merr.] and wheat (Triticum aestivum L.). The PR vs. WC relationships for two depths (0.21 and 0.27 m), below the level of cultivation, were similar to those at the 0.10-m depth for the nontrafficked no-till plots. These relationships for the 0.21- and 0.27-m depths were not influenced by tillage, traffic, and corn cropping system treatments. The variable depth of plowing in tilled plots was found to influence the data consistency for the 0.21-m depth, indicating the penetrometer's high sensitivity to the soil conditions.

Laboratory Calibration, In-Field Validation and Use of a Soil Penetrometer Measuring Cone Resistance and Water Content

Concurrent and coincident measure of penetrometer cone resistance (PR) and water content (WC) were optimized by hourly in-field validation of data from time domain transmissiometry (TDT) for WC and piezoelectric force sensor for PR. A piezoelectric force sensor coupled to a cone is followed by a helical wrapped TDT sensor on a single penetrometer shaft. Detailed laboratory calibrations, coupled with in-field validations, were important to assure the quality of data, which facilitated detailed analyses of PR and WC patterns. The piezoelectric sensor relied on a calibrated spring for the in-field validation. The calibration of the TDT sensor had three stages: a series of fluids of known dielectric constant; soil columns at known, variable water contents; and field soils at a range of ambient conditions. The penetrometer was used to study soil strength and WC behavior in time and space along 300-m plots. The treatments were conventional and no-till, each at two levels of traffic. The crop was corn (Zea mays L.), continuous and in rotation with soybean [Glycine max (L.) Merr.] and wheat (Triticum aestivum L.). The PR vs. WC relationships for two depths (0.21 and 0.27 m), below the level of cultivation, were similar to those at the 0.10-m depth for the nontrafficked no-till plots. These relationships for the 0.21- and 0.27-m depths were not influenced by tillage, traffic, and corn cropping system treatments. The variable depth of plowing in tilled plots was found to influence the data consistency for the 0.21-m depth, indicating the penetrometer's high sensitivity to the soil conditions.

Embedded temperature strain fibre Bragg grating sensor system validation for concrete structures

The transducer manufacture and calibration, the in-laboratory sensor system characterization and their in-field validation are described and discussed in this paper. This sensor system was installed in key zones of a bridge and was used to determine the characteristics of the structure during the load test. The results were successfully checked with those obtained by traditional means.