Uncertainty Of Measurement System Research Articles

Characterization of JWST NIRCam PSFs and Implications for AGN+host Image Decomposition

We present a detailed analysis of the point-spread function (PSF) of JWST NIRCam imaging in eight filters: F070W, F115W, F150W, F200W, F277W, F356W, F444W, and F480M, using publicly available data. Spatial variations in the PSF FWHM generally decrease with wavelength: the maximum and rms fractional variations are ∼20% and 5% in F070W, reduced to ∼3% and 0.6% in F444W. We compare three commonly used methods (SWarp, photutils, and PSFEx) to construct model PSFs and conclude that PSFEx delivers the best performance. Using simulated images of broad-line active galactic nuclei (AGNs), we evaluate the impact of PSF mismatches on the recoverability of host galaxy properties. Host fluxes are generally overestimated when adopting mismatched PSF models, with larger overestimation for more AGN-dominated systems. Broader PSFs tend to produce less concentrated hosts, while narrower PSFs tend to produce more concentrated and compact hosts. Systematic uncertainties in host measurements from PSF and model mismatches are generally larger than the formal fitting uncertainties for high signal-to-noise ratio data. Image decomposition can also lead to an artificial offset between the AGN and host centroids, which is common (e.g., >1σ [3σ] detection in ∼80% [∼20%–30%] of systems), and scales with the mean host surface brightness (SB). Near the SB limit, this artificial offset can reach as large as ∼80%, 26%, and 7% of R e in systems with R e = 0.″12, 0.″48, and 1.″92, respectively. We demonstrate our PSF construction and image decomposition methods with an example broad-line quasar at z = 1.646 in the CEERS field.

Statistical Analysis of Regenerative Air Preheater of Pulverized Coal Fired Boilers

Abstract: The data gathered from the field study and different parameter recorders connected to the data acquisition system of the distributed control system panel for measuring flow, pressure, and temperature are subject to typical systematic instrumentation measurement uncertainties with regard to the primary measuring elements, sensors, transducers, amplifiers, digital converters, and recorders, as well as the effects of the environment. The acceptability of data is statistically confirmed by taking into account the unpredictability of the inaccuracy in recorded parameters for temperature, pressure, and flow measurement. The statistical output on the measured and expected air flow through the APH (ma) in relation to different AAT (Tae) is summarized

Residual error correction for reducing the uncertainty of a sample-tracking robotic 3D measurement system

This paper presents a method for post-correction of disturbing relative motion between a robotic 3D measurement system and a sample under test. The active sample-tracking measurement platform carries a high-precision scanning confocal chromatic sensor acts as an end-effector of a robot, targeted for operation in a vibration-prone environment. The proposed method does not require any additional hardware and enables a point-by-point correction of the sequentially acquired 3D point cloud by the measured residual sample-tracking error. For experimental measurements at the maximum frame rate of 1fps in a workshop-like environment, which induces a resonant 47 Hz relative motion, the axial measurement error and uncertainty is reduced by 20% to 0.19µm and 0.25 µm, respectively.

Measuring cavity powers of active galactic nuclei in clusters using a hybrid X-ray–radio method

Measurements of the quantity of radio-mode feedback injected by an active galactic nucleus into the cluster environment have mostly relied on X-ray observations, which reveal cavities in the intracluster medium excavated by the radio lobes. However, the sensitivity required to accurately constrain the dimensions of these cavities has proven to be a major limiting factor and it is the main bottleneck of high-redshift measurements. We describe a hybrid method based on a combination of X-ray and radio observations, which aims to enhance our ability to study radio-mode feedback. In this paper, we present one of the first samples of galaxy clusters observed with the International LOFAR Telescope (ILT) at 144 MHz and use this sample to test the hybrid method at lower frequencies than before. By comparing our measurements with results found in literature based on the traditional method using only X-ray observations, we find that the hybrid method provides consistent results to the traditional method. In addition, we find that the correlation between the traditional method and the hybrid method improves as the X-ray cavities are more clearly defined. This suggests that using radio lobes as proxies for cavities may help to circumvent systematic uncertainties in the cavity volume measurements. Encouraged by the high volume of unique ILT observations which have been successfully processed, this hybrid method enables radio-mode feedback to be studied at high redshifts for the first time even for large samples of clusters.

Measurement and correlation of isobaric molar heat capacities of deep eutectic solvents consisting of choline chloride and triethylene glycol

Deep eutectic solvents are environmentally friendly substitutes to room temperature ionic liquids in broad engineering applications like biofuel purification, polymer synthesis, gas capture, and organic extraction. In this work, the isobaric molar heat capacities of deep eutectic solvents consisting of choline chloride and triethylene glycol (in molar ratio of 1: 3, 1: 4, and 1: 5) are investigated by flow method in the temperature from 334.91 K to 364.98 K and pressure from 0.19 MPa to 25.21 MPa. The relative expended uncertainty of measurement system is calculated to be 1.4 % within 95 % degree of confidence. Experimental results show that the isobaric molar heat capacity increases linearly with higher temperature and lower pressure. With choline chloride added in triethylene glycol, the heat capacity decreases linearly with the decreasing of triethylene glycol molar fraction. Finally, the correlation of these binary mixtures is established based on the experimental data with the maximum absolute relative deviation and average absolute relative deviation of 1.01 % and 0.31 %, respectively.

The Longest Delay: A 14.5 yr Campaign to Determine the Third Time Delay in the Lensing Cluster SDSS J1004+4112

We present new light curves for the four bright images of the five image cluster-lensed quasar gravitational lens system SDSS J1004+4112. The light curves span 14.5 yr and allow the measurement of the time delay between the trailing bright quasar image D and the leading image C. When we fit all four light curves simultaneously and combine the models using the Bayesian information criterion, we find a time delay of Δt DC = 2458.47 ± 1.02 days (6.73 yr), the longest ever measured for a gravitational lens. For the other two independent time delays we obtain Δt BC = 782.20 ± 0.43 days (2.14 yr) and Δt AC = 825.23 ± 0.46 days (2.26 yr), in agreement with previous results. The information criterion is needed to weight the results for light curve models with different polynomial orders for the intrinsic variability and the effects of differential microlensing. The results using the Akaike information criterion are slightly different, but, in practice, the absolute delay errors are all dominated by the ∼4% cosmic variance in the delays rather than the statistical or systematic measurement uncertainties. Despite the lens being a cluster, the quasar images show slow differential variability due to microlensing at the level of a few tenths of a magnitude.

Investigation of multiple-ion-source neutral beam operation conditions compatible with motional Stark effect diagnostics.

The motional Stark effect (MSE) diagnostic system at KSTAR (Korea Superconducting Tokamak Advanced Research) often suffers from the drawback of possible systematic uncertainties in measurements due to overlap of the MSE spectra generated from three different ion sources that constitute a single neutral beam injection system. In particular, one ion source injected in the most tangential direction always causes strong spectral overlaps which, therefore, imposes regulations and constraints on the energy combination among the ion sources. A Stokes-vector analysis has been performed to produce operation windows for the energy combination between the ion source used in the MSE measurement and the ion source with the largest tangential injection angle. The analysis includes various practical factors, such as the distortion of the transmission function of bandpass filters and pitch angle profiles collected from a vast amount of KSTAR discharges. The two-dimensional parameter space, or the contour plot, on the expected systematic offsets in the measured pitch angle has been generated from this analysis, which can serve as a quantitative guideline for operating the multiple-ion-source neutral beam heating system.

A Uniform Type Ia Supernova Distance Ladder with the Zwicky Transient Facility: Absolute Calibration Based on the Tip of the Red Giant Branch Method

The current Cepheid-calibrated distance ladder measurement of H 0 is reported to be in tension with the values inferred from the cosmic microwave background (CMB), assuming standard cosmology. However, some tip of the red giant branch (TRGB) estimates report H 0 in better agreement with the CMB. Hence, it is critical to reduce systematic uncertainties in local measurements to understand the Hubble tension. In this paper, we propose a uniform distance ladder between the second and third rungs, combining Type Ia supernovae (SNe Ia) observed by the Zwicky Transient Facility (ZTF) with a TRGB calibration of their absolute luminosity. A large, volume-limited sample of both calibrator and Hubble flow SNe Ia from the same survey minimizes two of the largest sources of systematics: host-galaxy bias and nonuniform photometric calibration. We present results from a pilot study using the existing TRGB distance to the host galaxy of ZTF SN Ia SN 2021rhu (aka ZTF21abiuvdk) in NGC7814. Combining the ZTF calibrator with a volume-limited sample from the first data release of ZTF Hubble flow SNe Ia, we infer H 0 = 76.94 ± 6.4 km s−1 Mpc−1, an 8.3% measurement. The error budget is dominated by the single object calibrating the SN Ia luminosity in this pilot study. However, the ZTF sample includes already five other SNe Ia within ∼20 Mpc for which TRGB distances can be obtained with the Hubble Space Telescope. Finally, we present the prospects of building this distance ladder out to 80 Mpc with James Webb Space Telescope observations of more than 100 ZTF SNe Ia.

Massive star-forming galaxies have converted most of their halo gas into stars

In the local Universe, the efficiency for converting baryonic gas into stars is very low. In dark matter halos where galaxies form and evolve, the average efficiency varies with galaxy stellar mass and has a maximum of about 20% for Milky-Way-like galaxies. The low efficiency at higher mass is believed to be the result of some quenching processes, such as the feedback from active galactic nuclei. We perform an analysis of weak lensing and satellite kinematics for SDSS central galaxies. Our results reveal that the efficiency is much higher, more than 60%, for a large population of massive star-forming galaxies around 1011 M⊙. This suggests that these galaxies acquired most of the gas in their halos and converted it into stars without being significantly affected by quenching processes. This population of galaxies is not reproduced in current galaxy formation models, indicating that our understanding of galaxy formation is incomplete. The implications of our results on circumgalactic media, star-formation quenching, and disk galaxy rotation curves are discussed. We also examine systematic uncertainties in halo-mass and stellar-mass measurements that might influence our results.

An Entropy Framework for Evaluating Reflectance Observations for Climate Studies

AbstractThis study evaluated the comparative entropy represented in shortwave (300–1,750 nm) passive remote sensing measurements from conceptual instruments with varying systematic measurement uncertainties and spectral resolutions. The focus was on spectral and broadband reflectance averaged over large spatial scales typically relevant for climate change studies. Information theory was applied to quantify how the normalized Shannon entropy changed for different conceptual instruments and over different spatial scales. Reflectance measurements from the Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY) were used to represent the observed reflectance, and simulated reflectance from climate Observing System Simulations Experiments (OSSEs) were used to represent decadal‐ and centennial‐length data sets free from instrument artifacts. Similar to previous studies, the simulated OSSE spectra were shown to be a sufficient proxy for the observed reflectance. As hypothesized, the normalized entropy decreased with increasing measurement uncertainty and increasing spectral bandwidth. Additionally, the entropy decreased for increasingly large spatial scales, particularly for measurement uncertainties larger than 2%. When applied to OSSE reflectance simulated from a forced CMIP3 climate model simulation, the change in entropy with measurement uncertainty and spectral resolution provided insight into measurement attributes needed to monitor a changing climate system and highlighted the importance of sufficiently high accuracy and spectral resolution for detecting and attributing climate trends. These preliminary studies illustrate the value of this information theory‐based framework in instrument design by calculating the entropy, used to represent information in measurements from different conceptual instruments.

E/B mode decomposition of HSC-Y1 cosmic shear using COSEBIs: Cosmological constraints and comparison with other two-point statistics

Abstract We perform a cosmic shear analysis of Hyper Suprime-Cam Subaru Strategic Program first-year data (HSC-Y1) using complete orthogonal sets of E/B-integrals (COSEBIs) to derive cosmological constraints. We compute E/B-mode COSEBIs from cosmic shear two-point correlation functions measured on an angular range of 4′ < θ < 180′. We perform a standard Bayesian likelihood analysis for cosmological inference from the measured E-mode COSEBIs, including contributions from intrinsic alignments of galaxies as well as systematic effects from point spread function model errors, shear calibration uncertainties, and source redshift distribution errors. We adopt a covariance matrix derived from realistic mock catalogs constructed from full-sky gravitational lensing simulations that fully take account of the survey geometry and measurement noise. For a flat Λ cold dark matter model, we find $S\,_8 \equiv \sigma _8\sqrt{\Omega _{\rm m}/0.3}=0.809_{-0.026}^{+0.036}$. We carefully check the robustness of the cosmological results against astrophysical modeling uncertainties and systematic uncertainties in measurements, and find that none of them has a significant impact on the cosmological constraints. We also find that the measured B-mode COSEBIs are consistent with zero. We examine, using mock HSC-Y1 data, the consistency of our S8 constraints with those derived from the other cosmic shear two-point statistics, the power spectrum analysis by Hikage et al. (2019, PASJ, 71, 43) and the two-point correlation function analysis by Hamana et al. (2020, PASJ, 72, 16), which adopt the same HSC-Y1 shape catalog, and find that all the S8 constraints are consistent with each other, although the expected correlations between derived S8 constraints are weak.

Energy levels of singly ionized and neutral zirconium

Improved energy levels for singly ionized and neutral zirconium of both even and odd parity are determined from Fourier Transform Spectrometer data using a least-squares optimization procedure. Data from interferometric spectrometers provides much tighter control of systematic uncertainties in line position measurements than was achieved using older (e.g. Rowland Circle) dispersive spectrometers.

Parallelism measurement method for nontransparent flat parts.

Nontransparent flat parts with weak rigidity are widely used in precision physics experiments, aerospace, and other fields in which parallelism is required. However, existing methods cannot meet requirements due to the limitation of measurement size and accuracy. This paper proposes a new method for measuring parallelism of nontransparent flat parts with high accuracy and then builds a submicrometer-level parallelism measuring system. The 3D model of the whole part is reconstructed by thickness and flatness, which are measured respectively. Subsequently, parallelism is evaluated by the principle of minimum directional zone. The method is verified by an experiment with a thin copper substrate sized ⊘200mm×2.48mm on the parallelism measuring system. The experiment result shows that the part's parallelism is 7.41 µm, and the expanded uncertainty of parallelism measurement system is 0.34 µm, k=2.

Synthetic galaxy clusters and observations based on Dark Energy Survey Year 3 Data

ABSTRACT We develop a novel data-driven method for generating synthetic optical observations of galaxy clusters. In cluster weak lensing, the interplay between analysis choices and systematic effects related to source galaxy selection, shape measurement, and photometric redshift estimation can be best characterized in end-to-end tests going from mock observations to recovered cluster masses. To create such test scenarios, we measure and model the photometric properties of galaxy clusters and their sky environments from the Dark Energy Survey Year 3 (DES Y3) data in two bins of cluster richness $\lambda \in [30; 45)$, $\lambda \in [45; 60)$ and three bins in cluster redshift ($z\in [0.3; 0.35)$, $z\in [0.45; 0.5)$ and $z\in [0.6; 0.65)$. Using deep-field imaging data, we extrapolate galaxy populations beyond the limiting magnitude of DES Y3 and calculate the properties of cluster member galaxies via statistical background subtraction. We construct mock galaxy clusters as random draws from a distribution function, and render mock clusters and line-of-sight catalogues into synthetic images in the same format as actual survey observations. Synthetic galaxy clusters are generated from real observational data, and thus are independent from the assumptions inherent to cosmological simulations. The recipe can be straightforwardly modified to incorporate extra information, and correct for survey incompleteness. New realizations of synthetic clusters can be created at minimal cost, which will allow future analyses to generate the large number of images needed to characterize systematic uncertainties in cluster mass measurements.

Enabling quantitative robot-assisted compressional elastography via the extended Kalman filter

Compressional or quasi-static elastography has demonstrated the capability to detect occult cancers in a variety of tissue types, however it has a serious limitation in that the resulting elastograms are generally qualitative whereas other forms of elastography, such as shear-wave, can produce absolute measures of elasticity for histopathological classification. We address this limitation by introducing a stochastic method using an extended Kalman filter and robot-assistance to obtain quantitative elastograms which are resilient to measurement noise and system uncertainty. In this paper, the probabilistic framework is described, which utilizes many ultrasound acquisitions obtained from multiple palpations, to fuse data and uncertainty from a robotic manipulator’s joint encoders and force/torque sensor directly into the inverse reconstruction of the elastogram. Quantitative results are demonstrated over homogeneous and inclusion gelatin phantoms using a seven degree of freedom manipulator for a range of initial elasticity assumptions. Results imply resilience to poorly assumed initial conditions as all trials were within 5 kPa of the elasticity measured by a mechanical testing system. Moreover, the presence or absence of an inclusion is clear in all reconstructed elastograms even when artifacts are present in displacement fields, indicating further robustness to measurement noise. The proposed stochastic method allows fusion of data from a robot’s sensors directly into compressional elastography image reconstruction which may stabilize optimization and improve accuracy. This approach provides a mathematical framework to readily incorporate measurements from additional sensors in future applications which may extend the capabilities of compressional elastography beyond that of producing quantitative elasticity measurements.

Dynamic Distributed Pressure Measurement Using Frequency-Agile Fast BOTDA

A distributed pressure sensor is proposed and designed for dynamic pressure measurement by using frequency-agile fast Brillouin optical time-domain analysis (BOTDA). A double coated single-mode fiber (SMF) is used as the sensing fiber because of its 1500- $\mu \text{m}$ thickness outer coating that can significantly improve the dependence of the Brillouin frequency shift on pressure. Then, the frequency-agile technique is used to generate frequency-agile pump pulse in BOTDA system so that a fast Brillouin gain spectrum distribution measurement can be achieved. An injection locked scheme is used as both optical filter and optical amplifier to improve the measurement accuracy. As a result, the static pressure sensitivity of the double coated fiber is −3.46 MHz/MPa with the pressure ranging from 0 to 30 MPa. Subsequently, a large dynamic range pressure measurement is performed with a sampling rate of 33.3 kHz and maximum sensing distance of 25 m. Furthermore, it is proved that the uncertainty of dynamic pressure measurement system is 0.03 MPa.

A measurement of two-photon exchange in Super-Rosenbluth separations with positron beams

The proton electric and magnetic form factors, $G_E$ and $G_M$, are intrinsically connected to the spatial distribution of charge and magnetization in the proton. For decades, Rosenbluth separation measurements of the angular dependence of elastic e$^-$-p scattering were used to extract $G_E$ and $G_M$. More recently, polarized electron scattering measurements, aiming to improve the precision of $G_E$ extractions, showed significant disagreement with Rosenbluth measurements at large momentum transfers ($Q^2$). This discrepancy is generally attributed to neglected two-photon exchange (TPE) corrections. At larger $Q^2$ values, a new `Super-Rosenbluth' technique was used to improve the precision of the Rosenbluth extraction, allowing for a better quantification of the discrepancy, while comparisons of e$^+$-p and e$^-$-p scattering indicated the presence of TPE corrections, but at $Q^2$ values below where a clear discrepancy is observed. In this work, we demonstrate the significant benefits to combining the Super-Rosenbluth technique with positron beam measurements. This approach provides a greater kinematic reach and is insensitive to some of the key systematic uncertainties in previous positron measurements.

Research and Implementation of the Sports Analysis System Based on 3D Image Technology

On the basis of existing research, this paper analyzes the algorithms and technologies of 3D image-based sports models in depth and proposes a fusion depth map in view of some of the shortcomings of the current hot spot sports model methods based on 3D images. We use the 3D space to collect the depth image, remove the background from the depth map, recover the 3D motion model from it, and then build the 3D model database. In this paper, based on the characteristics of continuity in space and smoothness in time of a rigid body moving target, a reasonable rigid body target motion hypothesis is proposed, and a three-dimensional motion model of a rigid body target based on the center of rotation of the moving target and corresponding motion is designed to solve the equation with parameters. In the case of unknown motion law, shape, structure, and size of the moving target, this algorithm can achieve accurate measurement of the three-dimensional rigid body motion target’s self-rotation center and related motion parameters. In the process of motion parameter calculation, the least square algorithm is used to process the feature point data, thereby reducing the influence of noise interference on the motion detection result and correctly completing the motion detection task. The paper gives the measurement uncertainty of the stereo vision motion measurement system through simulated and real experiments. We extract the human body motion trajectory according to the depth map and establish a motion trajectory database. For using the recognition algorithm of the sports model based on the 3D image, we input a set of depth map action sequences. After the above process, the 3D motion model is obtained and matched with the model in the 3D motion model database, and the sequence with the smallest distance is calculated. The corresponding motion trajectory is taken as the result of motion capture, and the efficiency of this system is verified through experiments.

The challenge of blending in large sky surveys

The increasing sensitivity of modern sky surveys allow ever fainter emissions of light to be detected, but it also increases the chances of noticeable overlap between multiple sources of light, a phenomenon called blending. The consequences of blending are expected to be among the leading systematic measurement uncertainties of future surveys, such as the Legacy Survey of Space and Time. This Perspective discusses two main approaches to addressing blending: attempting to separate individual sources and statistically correcting for the presence of blending at the population level. For both approaches, simultaneous access to data of multiple surveys will be critical to construct a joint data set that combines the strengths of each individual survey.

Traceability of optical 3D scanner measurements on sand mould in the production of quality castings

This paper addresses the establishment of traceability of optical 3D scanner measurements on green sand mould in the production of quality castings. Optical measurements are subject to the influence of the workpiece material optical properties, which can be very different from those of conventional calibration artefacts, e.g. check boards, ball plates, etc. This means that an optical 3D scanner calibrated using a check board or a ball plate may give biased and unreliable results when used for dimensional measurements on a crystalline material such as sand. In order to use a tactile coordinate measuring machine as reference for optical measurements on a green sand mould, which cannot be probed directly, a hard furan sand cone plate was developed and substituted as reference workpiece for tactile as well as optical measurements. Systematic errors and measurement uncertainties were assessed for the optical measurements, and a maximum expanded uncertainty of 26 µm was estimated, which is acceptable for optical measurements on sand surfaces having single grains with an average diameter of 232 µm.