scholarly journals Type B Uncertainty Analysis of Gravity-Based Determinations of Triaxial-Accelerometer Properties by Simulation of Measurement Errors

2022 ◽  
Vol 126 ◽  
Author(s):  
Jon Geist ◽  
Michael Gaitan
Keyword(s):  
Measurement Errors ◽  
Type B ◽  
Triaxial Accelerometer ◽  
Calibration System ◽  
Intrinsic Properties ◽  
Step Size ◽  
Sensitivity Matrix ◽  
The Individual ◽  
Rotation Stage ◽  
Alignment Errors

We simulated the effects of gimbal-alignment errors and rotational step-size errors on measurements of the sensitivity matrix and intrinsic properties of a triaxial accelerometer. We restricted the study to measurements carried out on a two-axis calibration system using a previously described measurement and analysis protocol. As well as imperfections in the calibration system, we simulated imperfect orthogonality of the accelerometer axes and non-identical sensitivity of the individual accelerometers in an otherwise perfect triaxial accelerometer, but we left characterization of other accelerometer imperfections such as non-linearity for future study. Within this framework, sensitivity-matrix errors are caused by imperfections in the construction and installation of the accelerometer calibration system, but not by the accelerometer imperfections included in the simulations. We use the results of this study to assign type B uncertainties to the components of the sensitivity matrix and related intrinsic properties due to imperfections in the measurement system. For calibrations using a reasonably well manufactured and installed multi-axis rotation stage such as that studied in this paper, we estimated upper bounds to the standard uncertainties of the order of 1 ×10−5 , 2 ×10−5 , 2 ×10−4 , and 5 ×10−5 for the intrinsic sensitivities, diagonal elements of the sensitivity matrix, off-diagonal elements of the sensitivity matrix, and zero-acceleration offsets, relative to a sensitivity-matrix element of 1, respectively, and 5 ×10−3 degrees for the intrinsic angles

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.

scholarly journals Orientation-Dependent Reflection of Structurally Coloured Butterflies

Biomimetics ◽  
2020 ◽  
Vol 5 (1) ◽  
pp. 5
Author(s):  
Sigrid Zobl ◽  
Bodo D. Wilts ◽  
Willi Salvenmoser ◽  
Peter Pölt ◽  
Ille C. Gebeshuber ◽  
...  
Keyword(s):  
Orientation Dependence ◽  
Butterfly Species ◽  
Butterfly Wing ◽  
Step Size ◽  
Photonic Structures ◽  
Light Interference ◽  
Important Input ◽  
Individual Scale ◽  
The Individual ◽  
Wing Scales

The photonic structures of butterfly wing scales are widely known to cause angle-dependent colours by light interference with nanostructures present in the wing scales. Here, we quantify the relevance of the horizontal alignment of the butterfly wing scales on the wing. The orientation-dependent reflection was measured at four different azimuth angles, with a step size of 90°, for ten samples—two of different areas of the same species—of eight butterfly species of three subfamilies at constant angles of illumination and observation. For the observed species with varying optical structures, the wing typically exhibits higher orientation-dependent reflections than the individual scale. We find that the measured anisotropy is caused by the commonly observed grating structures that can be found on all butterfly wing scales, rather than the local photonic structures. Our results show that the technique employed here can be used to quickly evaluate the orientation-dependence of the reflection and hence provide important input for bio-inspired applications, e.g., to identify whether the respective structure is suitable as a template for nano-imprinting techniques.

The Calibration of Thermocouples by Freezing-Point Baths and Empirical Equations

1959 ◽  
Vol 81 (2) ◽  
pp. 177-188 ◽  
Author(s):  
R. P. Benedict
Keyword(s):  
Digital Computer ◽  
High Speed ◽  
Freezing Point ◽  
Individual Characteristics ◽  
Empirical Equations ◽  
Test Results ◽  
Calibration System ◽  
Temperature Range ◽  
Experimental Values ◽  
The Individual

A calibration system is described which is based on the use of a few precisely determined experimental values obtained from freezing-point baths. Characteristics of the individual thermocouples at intermediate points are obtained by passing empirical equations of prescribed form through the test values. A program is reviewed, by which a high-speed digital computer accomplishes the necessary conversions, curve fittings, comparisons of individual characteristics with arbitrary reference tables, and the printing out of a table of differences. Test results for a series of iron-constantan thermocouples, over the temperature range 32–1225 F, are presented to illustrate the use of the system and the uncertainties involved. Comparisons are drawn between these results and those obtained by other methods.

Multi-Swarm Cuckoo Search Algorithm with Q-Learning Model

2020 ◽  
Author(s):  
Juan Li ◽  
Dan-dan Xiao ◽  
Ting Zhang ◽  
Chun Liu ◽  
Yuan-xiang Li ◽  
...  
Keyword(s):  
Search Algorithm ◽  
Size Control ◽  
Cuckoo Search ◽  
Cuckoo Search Algorithm ◽  
Local Optimum ◽  
Step Size ◽  
Q Learning ◽  
Fitness Value ◽  
The Individual ◽  
Evolution Effect

Abstract As a novel swarm intelligence optimization algorithm, cuckoo search (CS) has been successfully applied to solve diverse problems in the real world. Despite its efficiency and wide use, CS has some disadvantages, such as premature convergence, easy to fall into local optimum and poor balance between exploitation and exploration. In order to improve the optimization performance of the CS algorithm, a new CS extension with multi-swarms and Q-Learning namely MP-QL-CS is proposed. The step size strategy of the CS algorithm is that an individual fitness value is examined based on a one-step evolution effect of an individual instead of evaluating the step size from the multi-step evolution effect. In the MP-QL-CS algorithm, a step size control strategy is considered as action, which is used to examine the individual multi-stepping evolution effect and learn the individual optimal step size by calculating the Q function value. In this way, the MP-QL-CS algorithm can increase the adaptability of individual evolution, and a good balance between diversity and intensification can be achieved. Comparing the MP-QL-CS algorithm with various CS algorithms, variants of differential evolution (DE) and improved particle swarm optimization (PSO) algorithms, the results demonstrate that the MP-QL-CS algorithm is a competitive swarm algorithm.

scholarly journals Eccentricity Parameters Identification for a Motorized Spindle System Based on Improved Maximum Likelihood Method

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Wengui Mao ◽  
Chaoliang Hu ◽  
Jianhua Li ◽  
Zhonghua Huang ◽  
Guiping Liu
Keyword(s):  
Maximum Likelihood ◽  
Measurement Errors ◽  
Maximum Likelihood Method ◽  
Search Algorithm ◽  
A Priori ◽  
Likelihood Method ◽  
Step Size ◽  
Spindle System ◽  
Grinding Machine ◽  
Search Interval

As a kind of rotor system, the electric spindle system is the core component of the precision grinding machine. The vibration caused by the mass imbalance is the main factor that causes the vibration of the grinding machine. Identifying the eccentricity parameters in an electric spindle system is a key issue in eliminating mass imbalances. It is difficult for engineers to understand the approximate range of eccentricity by experience; that is, it is difficult to obtain a priori information about eccentricity. At the same time, due to the geometric characteristics of the electrospindle system, the material factors and the randomness of the measurement response, these uncertain factors, even in a small case, are likely to cause large deviations in the eccentricity recognition results. The search algorithm used in the maximum likelihood method to identify the eccentricity parameters of the electrospindle system is computationally intensive, and the sensitivity in the iterative process brings some numerical problems. This paper introduces an Advance-Retreat Method (ARM) of the search interval to the maximum likelihood method, the unknown parameter increment obtained by the maximum likelihood method is used as the step size in the iteration, and the Advance-Retreat Method of the search interval is used to adjust the next design point so that the objective function value is gradually decreasing. The recognition results under the three kinds of measurement errors show that the improved maximum likelihood method improves the recognition effect of the maximum likelihood method and can reduce the influence of uncertainty factors on the recognition results, and the robustness is satisfactory.

Effect of Urate on Calcium Oxalate Crystallization in Human Urine: Evidence for a Promotory Role of Hyperuricosuria in Urolithiasis

1990 ◽  
Vol 79 (1) ◽  
pp. 9-15 ◽  
Author(s):  
Phulwinder K. Grover ◽  
Rosemary L. Ryall ◽  
Villis R. Marshall
Keyword(s):  
Calcium Oxalate ◽  
Human Urine ◽  
Stone Formation ◽  
Calcium Oxalate Monohydrate ◽  
Convincing Evidence ◽  
Urine Samples ◽  
Type B ◽  
Calcium Oxalate Dihydrate ◽  
Median Volume ◽  
The Individual

1. The effect of hyperuricosuria, simulated by increasing the concentration of dissolved urate, on the crystallization of calcium oxalate in human urine was examined. 2. Twenty urine samples were studied. Ten of these, designated type A, spontaneously precipitated calcium oxalate dihydrate crystals upon the addition of a solution of sodium urate solution which raised the median urate concentration from 3.1 to 7.0 mmol/l. 3. Adding dissolved urate to the remaining type B samples raised the median urate concentration from 2.2 to 6.2 mmol/l, but did not cause the precipitation of calcium oxalate. This was induced in these samples by the addition of a standard load of oxalate above an empirically determined metastable limit. 4. In the type B urine samples, the addition of urate decreased the median metastable limit from 125 to 66 μmol of oxalate, trebled the median volume of crystalline calcium oxalate deposited from 35 000 to 105 000 μm3/μl and significantly increased the overall size of the particles precipitated. Calcium oxalate monohydrate was exclusively precipitated, and the individual crystals deposited in the presence of urate were markedly smaller, more numerous, and more highly aggregated than those produced in its absence. 5. These results constitute the most convincing evidence yet obtained that hyperuricosuria may be a powerful promoter of calcium oxalate stone formation.

scholarly journals Strategies to enhance radiosensitivity in breast cancer

2008 ◽  
Vol 11 (8) ◽  
Author(s):  
S. C. Formenti
Keyword(s):  
Breast Cancer ◽  
Signal Transduction ◽  
Normal Tissue ◽  
Tumor Response ◽  
Signal Transduction Pathways ◽  
Intrinsic Properties ◽  
Host Interactions ◽  
Radiation Treatments ◽  
The Individual ◽  
Effective Radiation

AbstractRadiotherapy is an important component in the treatment of breast cancer. However, the individual tumor response to radiation is variable, reflecting both the intrinsic properties of the tumor and its microenvironment as well as the different, inherited sensitivity of the patient's normal tissue when exposed to the effect of ionizing radiation. These differences have inspired research to discover the underlying signal transduction pathways and to understand when they pertain to the tumor, the host or both. In fact, understanding the mechanisms underlying radiosensitivity of breast cancer not only does it permit to design more effective radiation treatments, but it sheds light on the complexities of tumor-host interactions in this disease.

scholarly journals Regulatory Issues Associated With Shipment of Small Quantities of Radioactive Material

2010 ◽  
Author(s):  
Allen C. Smith ◽  
Glenn A. Abramczyk ◽  
Stephen J. Nathan
Keyword(s):  
General Purpose ◽  
Academic Programs ◽  
Department Of Energy ◽  
National Standards ◽  
Radioactive Material ◽  
Type B ◽  
Radioactive Materials ◽  
Individual Activity ◽  
High Integrity ◽  
The Individual

Following decertification of the ubiquitous and simple Department of Transpsortaion (DOT) 6M specification package, radioactive materials package Shippers have been faced with the need to use Certified Type B packagings. Many Department of Energy (DOE), commercial and academic programs have a need to ship small masses of radioactive material, where the identity of the material or radionuclides is know but the individual activity of some may not be known. For quantities which are small enough to be fissile exempt and have adequate shielding to ensure low radiation levels, these materials could be transported in a package which provides the required containment level. Because their Chalfant type containment vessels meet the American National Standards Institute (ANSI) N14.5 definition for leak-tight (≤ 1×10−7 ref cm3 air/sec), the 9975, 9977, and 9978 are capable of transporting contents requiring the highest standard of containment. The issues associated with certification of a high-integrity, general purpose package for shipping small quantities of such radioactive material are discussed and the logical basis for certification for such contents is described.

scholarly journals freqpcr: estimation of population allele frequency using qPCR ΔΔCq measures from bulk samples

2021 ◽  
Author(s):  
Masaaki Sudo ◽  
Masahiro Osakabe
Keyword(s):  
Allele Frequency ◽  
Measurement Errors ◽  
Interval Estimation ◽  
R Package ◽  
Bulk Sample ◽  
Dna Yield ◽  
Rare Mutations ◽  
Population Allele Frequency ◽  
The Individual ◽  
Pcr Techniques

AbstractPCR techniques, both quantitative (qPCR) and non-quantitative, have been used to estimate allele frequency in a population. However, the labor required to sample numerous individuals, and subsequently handle each sample, makes quantification of rare mutations, including pesticide resistance genes at the early stages of resistance development, challenging. Meanwhile, pooling DNA from multiple individuals as a “bulk sample” may reduce handling costs. The qPCR output for a bulk sample, however, contains uncertainty owing to variations in DNA yields from each individual, in addition to measurement errors. In this study, we developed a statistical model for the interval estimation of allele frequency using ΔΔCq-based qPCR analyses of multiple bulk samples collected from a population. We assumed a gamma distribution as the individual DNA yield and developed an R package for parameter estimation, which was verified with real DNA samples from acaricide-resistant spider mites, as well as a numerical simulation. Our model resulted in unbiased point estimates of the allele frequency compared with simple averaging of the ΔΔCq values, while their confidence intervals suggest that collecting and pooling additional samples from individuals may produce higher precision than individual PCR tests with moderate sample sizes.

An Algorithm for the Rational Choice of Sodium Profile during Hemodialysis

1997 ◽  
Vol 20 (12) ◽  
pp. 659-672 ◽  
Author(s):  
M. Ursino ◽  
L. Colì ◽  
V. Dalmastri ◽  
F. Volpe ◽  
G. La Manna ◽  
...  
Keyword(s):  
Measurement Errors ◽  
A Priori ◽  
Sodium Concentration ◽  
Individual Characteristics ◽  
Dialysis Session ◽  
A New Technique ◽  
The Individual ◽  
Dialysate Sodium

The incidence of intradialytic disequilibrium syndrome and symptomatic hypotension has increased significantly among dialysis patients over the last ten years. Profiled hemodialysis (PHD) is a new technique, based on the intradialytic modulation of dialysate sodium concentration, which aspires to reduce to previous imbalances. This paper presents a new algorithm for the determination of a rational dialysate sodium profile during PHD. A mathematical model of solute kinetics, monocompartmental for sodium and bicompartmental for urea is used. The algorithm allows the sodium profile to be elaborated a priori before each dialysis session, respecting the individual sodium mass removal and weight gain. A procedure allowing the adjustment of the method to the individual characteristics, on the basis of routine measurements performed before each session is also presented. The method was validated during seven dialysis sessions. Comparison between data measured in vivo and those predicted by the model showed standard deviations corresponding to the range of laboratory measurement errors: 1.50 mEq/L for sodium and 0.87 mmol/L for urea. In vivo implementation of PHD by our algorithm allows one to remove an amount of sodium close to that established a priori on the basis of patient's need.

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