Analyzing plane-angle measurement errors by means of a dynamoelectric angle-to-time interval converter

1974 ◽  
Vol 17 (1) ◽  
pp. 15-19
Author(s):  
S. A. Kialdunozyants ◽  
V. L. Inosov ◽  
V. I. Pronenko
Keyword(s):  
Measurement Errors ◽  
Angle Measurement ◽  
Time Interval ◽  
Plane Angle

scholarly journals Gravity-Based Characterization of Three-Axis Accelerometers in Terms of Intrinsic Accelerometer Parameters

2017 ◽  
Vol 122 ◽  
Author(s):  
Jon Geist ◽  
Muhammad Yaqub Afridi ◽  
Craig D. McGray ◽  
Michael Gaitan
Keyword(s):  
Gravitational Field ◽  
Coordinate System ◽  
Measurement Errors ◽  
Angle Measurement ◽  
Sensitivity Matrix ◽  
Cross Sensitivity ◽  
Measurement Capability ◽  
Intrinsic Parameters ◽  
The Cross ◽  
Alignment Errors

Cross-sensitivity matrices are used to translate the response of three-axis accelerometers into components of acceleration along the axes of a specified coordinate system. For inertial three-axis accelerometers, this coordinate system is often defined by the axes of a gimbal-based instrument that exposes the device to different acceleration inputs as the gimbal is rotated in the local gravitational field. Therefore, the cross-sensitivity matrix for a given three-axis accelerometer is not unique. Instead, it depends upon the orientation of the device when mounted on the gimbal. We define nine intrinsic parameters of three-axis accelerometers and describe how to measure them directly and how to calculate them from independently determined cross-sensitivity matrices. We propose that comparisons of the intrinsic parameters of three axis accelerometers that were calculated from independently determined cross-sensitivity matrices can be useful for comparisons of the cross-sensitivity-matrix measurement capability of different institutions because the intrinsic parameters will separate the accelerator-gimbal alignment differences among the participating institutions from the purely gimbal-related differences, such as gimbal-axis orthogonality errors, z-axis gravitational-field alignment errors, and angle-setting or angle-measurement errors.

An Application of Relay Feedback to Mass Measurement Under Weightless Conditions

2007 ◽  
Author(s):  
Takeshi Mizuno ◽  
Minoru Takeuchi ◽  
Yuji Ishino ◽  
Masaya Takasaki
Keyword(s):  
Measurement Errors ◽  
Mass Measurement ◽  
Dead Zone ◽  
Voice Coil Motor ◽  
Feedback System ◽  
Time Interval ◽  
Force Output ◽  
Relay Feedback ◽  
Relay Element ◽  
Measurement Object

Relay feedback was applied to measuring mass even under weightless conditions. A measurement object is driven by a force-output actuator. The motion of the object is controlled by a relay feedback system. The used relay element has dead zone and switches force acting on the object in relation to the position of the measurement object. The mass of the object is determined from the time interval measurement of the on-state and off-state periods. An apparatus was developed for experimental study. It uses a voice coil motor as an actuator, and a pair of photo interrupters for detecting the switching positions. The effects of system parameters on measurement accuracy were studied experimentally. Under the tuned conditions, the measurement errors were within 0.2[%]. Measurement on a base moving freely was also carried out.

Assessment of the measuring errors in tipping rain gauge located on a small mountain basin

2020 ◽  
Author(s):  
Leonor Rodriguez-Sinobas ◽  
Daniel Alberto Segovia-Cardozo ◽  
Sergio Zubelzu ◽  
Enrique Estefania ◽  
Andrés Díez-Herrero
Keyword(s):  
Measurement Errors ◽  
Rain Gauge ◽  
Sampling Procedure ◽  
Irrigation Scheduling ◽  
Time Interval ◽  
Manufacturing Cost ◽  
Calibration Data ◽  
Rain Gauges ◽  
Precipitation Measurement ◽  
High Precipitation

<p>Precipitation measurement has always been of human interest. Its estimation can guide the decisions concerning flooding prevention and irrigation scheduling in semi-arid regions.</p><p>Nowadays, manufactures offer several types of rain gauges. Among them, the tipping-bucket rain gauges (TBRs) is the most frequently used worldwide to collect rainfall data. It structure is simple and the manufacturing cost is reasonable. Also, the operating mechanical mechanism saves energy and can be easily automated. Its manufacture began in the seventeenth century although the recent models have improved their original characteristics.</p><p>Likewise, these gauges have some disadvantages such us: measurement errors, that can be significant during heavy rainfall or light drizzle; losses from evaporation and wind effects; time of onset; sampling procedure and rain residue in the bucket. Therefore, calibration is often needed.</p><p>This study assesses the data from a set of 12 TBRs spread in the small mountain basin “Venero Claro”, Avila (Spain). This is highly monitored due to its capacity to generate torrential flows and flash floods.  The data comprised a time interval of 14 years; the oldest TBRs were installed in 2006. The objective was quantified the errors, especially those caused by high precipitation intensities, which are common in the area. Thus, calibration curves for data analysis were estimated by a dynamic laboratory calibration for two different TBRs’ models.</p><p>The results from the calibration data have been statistically analysed in order to determine the errors and their significance along time and topography. A significant underestimation was observed in TBRs, especially in those located at higher areas.</p>

scholarly journals Extreme Flood Response: The June 2008 Flooding in Iowa

2013 ◽  
Vol 14 (6) ◽  
pp. 1810-1825 ◽  
Author(s):  
James A. Smith ◽  
Mary Lynn Baeck ◽  
Gabriele Villarini ◽  
Daniel B. Wright ◽  
Witold Krajewski
Keyword(s):  
Measurement Errors ◽  
Weather Research And Forecasting ◽  
Time Interval ◽  
Antecedent Soil Moisture ◽  
Study Region ◽  
Flood Peak ◽  
Extreme Flood ◽  
Flood Response ◽  
Extreme Flooding ◽  
Cedar Rapids

Abstract The authors examine the hydroclimatology, hydrometeorology, and hydrology of extreme floods through analyses that center on the June 2008 flooding in Iowa. The most striking feature of the June 2008 flooding was the flood peak of the Cedar River at Cedar Rapids (3964 m3 s−1), which was almost twice the previous maximum from a record of 110 years. The spatial extent of extreme flooding was exceptional, with more U.S. Geological Survey stream gauging stations reporting record flood peaks than in any other year. The 2008 flooding was produced by a sequence of organized thunderstorm systems over a period of two weeks. The authors examine clustering and seasonality of flooding in the Iowa study region and link these properties to features of the June 2008 flood event. They examine the environment of heavy rainfall in Iowa during June 2008 through analyses of composite rainfall fields (15-min time interval and 1-km spatial resolution) developed with the Hydro-NEXRAD system and simulations using the Weather Research and Forecasting Model (WRF). Water balance analyses of extreme flood response, based on rainfall and discharge observations from basins with extreme flooding, suggest that antecedent soil moisture plays a diminishing role in flood response as the return interval increases. Rainfall structure and evolution play a critical and poorly understood role in determining the scaling of flood response. As in other extreme flood studies, analyses of the Iowa flood data suggest that measurement errors can be significant for record discharge estimates.

scholarly journals AUTOMATED TWO-CHANNEL PIEZOELECTRIC GRAVIMETER AGS

2021 ◽  
Vol 295 (2) ◽  
pp. 147-150
Author(s):  
OLENA BEZVESILNA ◽  
◽  
YURIY KYRYCHUK ◽  
NATALIA NAZARENKO ◽  
ANDREW TKACHUK ◽  
...  
Keyword(s):  
Output Signal ◽  
Measurement Errors ◽  
Physical Phenomenon ◽  
Ultrasonic Waves ◽  
Piezoelectric Transducers ◽  
Time Interval ◽  
Vertical Acceleration ◽  
Sensing Element ◽  
Dual Channel ◽  
Useful Signal

The purpose of the article is to obtain the basic working equation of motion of a dual-channel piezoelectric gravimeter of the aviation gravimetric system; to prove that a new dual-channel piezoelectric gravimeter has greater accuracy than the known ones. Today, piezoelectric transducers are used to determine the internal defects of solids with the help of ultrasonic waves, to measure the speed of ultrasound, as well as in medicine, mechanical engineering, geophysics, etc. Intensive development of new types of piezoelectric transducers is also carried out in Ukraine. The scientific works of Ukrainian scientists consider the use of piezoelectric transducers only as accelerometers but do not indicate the possibility of their use as dual-channel aviation gravimeters for measuring the acceleration of gravity. From the above review of prominent scientific works, it is clear that there is no information as to the use of the physical phenomenon of the direct piezoelectric effect to create a dual-channel gravity AGS more accurate than a known one. Improving the measurement accuracy in the automated dual-channel piezogravimeter is provided by the fact that the second measurement channel is created. To do this, the sensing element is made with two channels. The output electrical signals of the piezoelectric plates of both channels are summed in the adder. The output signal from the adder is fed to the device for calculating the output signal of the gravimeter (on-board computer), where it is calculated for a certain time interval. As a result, we get the output that contains a double signal of gravity acceleration. It is completely free of such measurement errors, which are caused by the influence of vertical acceleration, instrumental errors and errors from the non-identity of the two channels. The principle of operation of the new dual-channel piezogravimeter is described, its structural scheme is shown. It is shown that it is realistic to achieve greater accuracy of the piezogravimeter AGS (0.5 mGal) by compensating for errors from the influence of vertical acceleration (103 times the useful signal) and instrumental errors and errors from the residual non-identity of the two channels.

scholarly journals Tibial plateau angle: methods of measurement, value, applicability

2017 ◽  
Vol 73 (9) ◽  
pp. 532-537
Author(s):  
Adam Przeworski ◽  
Joanna Głodek ◽  
Zbigniew Adamiak
Keyword(s):  
Measurement Errors ◽  
Tibial Plateau ◽  
Cruciate Ligament ◽  
Clinical Importance ◽  
Angle Measurement ◽  
Radiographic Examination ◽  
Cranial Cruciate Ligament ◽  
Stifle Joint ◽  
Maximum Tolerance ◽  
Cranial Cruciate Ligament Disease

The tibial plateau angle measurement and its applicability have been reviewed based on the literature. The measurement was made on radiographs of the stifle joint with superimposition of the femoral condyles (with maximum tolerance of 2.0-4.0mm). Due to great variation among dog populations (size, breed), mean tibial plateau angles were found to be between 16.9° and 34°, but an excessive angle was described as >35°. An appropriate measurement of the tibial plateau angle can be made at about 108 days of age. The influence on the magnitude of the measured tibial plateau angle were the limb position during radiographic examination, the measurement technique (with modifications) and the experience level of the observer. Differences in magnitudes of the tibial plateau angles in dogs with and without cranial cruciate ligament rupture were not observed. The tibial plateau angle is commonly used in osteotomy of the tibia and its magnitude in order to select the proper surgical technique. The significance of the tibial plateau angle on the aetiopathogenesis of cranial cruciate ligament disease is questionable. Other measurements of the proximal tibia were attained to determine the risk factor of cranial cruciate ligament insufficiency. Knowledge of the tibial plateau angle and factors influencing measurement errors have great clinical importance.

scholarly journals Biological control of caterpillar sugarcane (Diatraea saccharalis) considering interval mathematical models

BIOMATH ◽  
2016 ◽  
Vol 5 (1) ◽  
pp. 1604232
Author(s):  
José Renato Campos ◽  
Edvaldo Assuncao ◽  
Geraldo Nunes Silva ◽  
Weldon Lodwick
Keyword(s):  
Biological Control ◽  
Mathematical Models ◽  
Control Problem ◽  
Measurement Errors ◽  
Crop Yields ◽  
Time Interval ◽  
Agricultural Practice ◽  
Programming Technique ◽  
Control Techniques ◽  
Lack Of Information

Biological control is a sustainable agricultural practice that was introduced to improve crop yields and has been highlighted among the various pest control techniques. However, real mathematical models that describe biological control models can have errors measurements or even are built with lack of information. In these cases, intervals may be feasible to show the lack of information or even measurement errors. So we consider interval mathematical models to represent the biological control problem. Specifically, in the present paper we illustrated the solution of discrete time interval optimal control problem for a practical application of biological control. To solve the problem, we used the single level constrained interval arithmetic [8] and the dynamic programming technique [2], along with the idea proposed in [22] for the solution of interval problem.

Direct Determination rather than Oscillometric Estimation of Systolic Blood Pressure in Patients with Severe Chronic Kidney Disease

2022 ◽  
pp. 1-9
Author(s):  
Amir M. Benmira ◽  
Olivier Moranne ◽  
Camelia Prelipcean ◽  
Emilie Pambrun ◽  
Michel Dauzat ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Chronic Kidney Disease ◽  
Kidney Disease ◽  
Systolic Blood Pressure ◽  
Pulse Pressure ◽  
Measurement Errors ◽  
Blood Pressure Measurement ◽  
Time Interval ◽  
Ckd Stage ◽  
Korotkoff Sounds

<b><i>Introduction:</i></b> Although arterial hypertension is a major concern in patients with chronic kidney disease (CKD), obtaining accurate systolic blood pressure (SBP) measurement is challenging in this population for whom automatic oscillometric devices may yield erroneous results. <b><i>Methods:</i></b> This cross-sectional study was conducted in 89 patients with stages 4, 5, and 5D CKD, for whom we compared SBP values obtained by the recently described systolic foot-to-apex time interval (SFATI) technique which provides direct SBP determination, the standard technique (Korotkoff sounds), and oscillometry. We investigated the effects of age, sex, diabetes, CKD stage, and pulse pressure to explain measurement errors defined as biases or misclassification relative to the SBP thresholds of 110–130-mm Hg. <b><i>Results:</i></b> All 3 techniques showed satisfactory reproducibility for SBP measurement (CCC &#x3e; 0.84 and &#x3e;0.91, respectively, in dialyzed and nondialyzed patients). The mean ± SD from SBP as determined via Korotkoff sounds was 1.7 ± 4.6 mm Hg for SFATI (CCC = 0.98) and 5.9 ± 9.3 mm Hg for oscillometry (CCC = 0.88). Referring to the 110–130-mm Hg SBP range outside which treatment prescription or adaptation is recommended for CKD patients, SFATI underestimated SBP in 3 patients and overestimated it in 1, whereas oscillometry underestimated SBP in 12 patients and overestimated it in 3. Higher pulse pressure was the main explanatory factor for measurement and classification errors. <b><i>Discussion/Conclusion:</i></b> SFATI provides accurate SBP measurements in patients with severe CKD and paves the way for the standardization of automated noninvasive blood pressure measurement devices. Before prescribing or adjusting antihypertensive therapy, physicians should be aware of the risk of misclassification when using oscillometry.

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