Causes Of Inaccuracy Research Articles

Research on the Detection Principle of Coal Ash by X-Ray Transmission Based on FLUKA

This study addresses the timely and accurate measurement of coal ash content by proposing a detection model based on nuclear science technology, which is validated using FLUKA 4-4.0 simulation software. The background provided highlights the fact that coal ash content is a critical sales indicator, and its precise measurement is essential for adjusting production parameters in coal preparation plants. In terms of methodology, this study employs the widely used FLUKA4-4.0 software in the field of nuclear physics to simulate X-ray transmission through coal, investigating the impact of changes in coal type on the accuracy of ash measurements. The results indicate that, when the proportions of high-atomic-number elements in coal remain constant, the ash measurement results are accurate and reliable. However, significant fluctuations occur when these proportions change. The conclusion emphasizes the fact that variations in coal type are the primary cause of inaccuracies in ash measurement, particularly when the ratios of high-atomic-number elements are altered. This research provides a new perspective on the online measurement of coal ash content and offers theoretical support for improving measurement accuracy.

Effects of adaptive backlash minimization in worm gear for precision positioning

The paper introduces innovative solutions for worm gears, aiming at adaptive reduction of side clearance to improve accuracy. It addresses manufacturing challenges affecting tooth dimensions and deviations in shape, examining the impact of adjustment settings on clearance components. The document outlines patented solutions and identifies the causes of inaccuracies in worm gears, with a specific focus on the efficiency of a compliant worm in reducing side clearance. Comprehensive analyses were conducted using Matlab, CAD, and empirical data to investigate the impact of adjustments on clearance statistics, correlation, and spectral analyses before and after corrections. It establishes correlations between clearance parameters and assesses positioning accuracy using a rolling screw system. By demonstrating significant improvements in accuracy without the need for gear disassembly during operation, the developed gear compensates for manufacturing deviations. The paper also suggests assembly procedures for precision worm gears in small-scale production, taking into account various criteria for accuracy assessment.

Monte Carlo simulation of the effect of melanin concentration on light-tissue interactions for transmittance pulse oximetry measurement.

Questions about the accuracy of pulse oximeters in measuring arterial oxygen saturation ( ) in individuals with darker skin pigmentation have resurfaced since the COVID-19 pandemic. This requires investigation to improve patient safety, clinical decision making, and research. We aim to use computational modeling to identify the potential causes of inaccuracy in measurement in individuals with dark skin and suggest practical solutions to minimize bias. An in silico model of the human finger was developed to explore how changing melanin concentration and arterial oxygen saturation ( ) affect pulse oximeter calibration algorithms using the Monte Carlo (MC) technique. The model generates calibration curves for Fitzpatrick skin types I, IV, and VI and an range between 70% and 100% in transmittance mode. was derived by inputting the computed ratio of ratios for light and dark skin into a widely used calibration algorithm equation to calculate bias ( ). These were validated against an experimental study to suggest the validity of the Monte Carlo model. Further work included applying different multiplication factors to adjust the moderate and dark skin calibration curves relative to light skin. Moderate and dark skin calibration curve equations were different from light skin, suggesting that a single algorithm may not be suitable for all skin types due to the varying behavior of light in different epidermal melanin concentrations, especially at 660nm. The ratio between the mean bias in White and Black subjects in the cohort study was 6.6 and 5.47 for light and dark skin, respectively, from the Monte Carlo model. A linear multiplication factor of 1.23 and exponential factor of 1.8 were applied to moderate and dark skin calibration curves, resulting in similar alignment. This study underpins the careful re-assessment of pulse oximeter designs to minimize bias in measurements across diverse populations.

Intraoperative Frozen Section Analysis and an Audit of its Diagnostic Accuracy: A Cross-sectional Study from Maharashtra, India

Introduction: Frozen Section (FS) is a diagnostic technique performed intraoperatively to obtain relevant information about the primary diagnosis, margin status, or sentinel lymph nodes, which helps guide the course of surgery. With the prevalent use of FS, it is imperative to recognise and scrutinise its diagnostic pitfalls and make efforts for rectification. Aim: To compare diagnostic results obtained on FS with final paraffin-embedded histopathology and calculate the Diagnostic Accuracy (DA) of FS. Materials and Methods: This cross-sectional study was conducted in the Department of Pathology at a tertiary care hospital, DVVPFs Medical College in Ahmednagar district, Maharashtra, India over a period of two years from January 1, 2020, to December 31, 2021. The diagnosis provided on specimens received for intraoperative FS was compared with the final histopathological diagnosis, considered as the gold standard for the same specimen. The results were categorised as concordant, discordant, and deferred cases. The diagnosis on FS and the final histopathological diagnosis, along with relevant clinical data, were entered into an excel sheet. Further, the DA of FS was calculated. All the discordant cases were analysed. Statistical analysis utilised simple percentage calculations from the excel sheet. Results: A total of 130 cases were analysed using FS, with the most common indication being sentinel lymph node analysis to detect metastatic deposits in 72 (55.4%) cases. Out of the total 130 cases, 119 (91.5%) were concordant, 10 (7.7%) were discordant, and 1 (0.8%) was deferred due to an insufficient specimen. Therefore, the overall DA rate was found to be 91.5% with an error rate of 8.5%. Upon analysis of the 10 discordant cases, the cause of inaccuracy was technical error in 7 (70%) cases and interpretation error in 3 (30%) cases. Conclusion: The DA obtained in the present study was somewhat lower than expected due to technical errors during FS sectioning, leading to artifacts, especially during lymph node processing. Analysis of the discordant cases unveiled this deficit. Therefore, such assessment studies should be performed periodically as they assist in highlighting the shortfalls and provide a plan to boost DA.

Industry CPD: Accuracy and precision in finite-element analysis

This CPD module, sponsored by Oasys, explains what we mean by accuracy and precision, looks at possible causes of inaccuracy when conducting a finite-element analysis, and discusses the role of validation and verification in checking the accuracy of modelling output.

Quantifying Coincidence in Non-Uniform Time Series with Mutual Graph Approximation: Speech and ECG Examples

Compressive sensing and arbitrary sampling are techniques of data volume reduction challenging the Shannon sampling theorem and expected to provide efficient storage while preserving original information. Irregularity of sampling is either a result of intentional optimization of a sampling grid or stems from sporadic occurrence or intermittent observability of a phenomenon. Quantitative comparison of irregular patterns similarity is usually preceded by a projection to a regular sampling space. In this paper, we study methods for direct comparison of time series in their original non-uniform grids. We also propose a linear graph to be a representation of the non-uniform signal and apply the Mutual Graph Approximation (MGA) method as a metric to infer the degree of similarity of the considered patterns. The MGA was implemented together with four state-of-the-art methods and tested with example speech signals and electrocardiograms projected to bandwidth-related and random sampling grids. Our results show that the performance of the proposed MGA method is comparable to most accurate (correlation of 0.964 vs. Frechet: 0.962 and Kleinberg: 0.934 for speech signals) and to less computationally expensive state-of-the-art distance metrics (both MGA and Hausdorf: O(L1+L2)). Moreover, direct comparison of non-uniform signals can be equivalent to cross-correlation of resampled signals (correlation of 0.964 vs. resampled: 0.960 for speech signals, and 0.956 vs. 0.966 for electrocardiograms) in applications as signal classification in both accuracy and computational complexity. Finally, the bandwidth-based resampling model plays a substantial role; usage of random grid is the primary cause of inaccuracy (correlation of 0.960 vs. for random sampling grid: 0.900 for speech signals, and 0.966 vs. 0.878, respectively, for electrocardiograms). These figures indicate that the proposed MGA method can be used as a simple yet effective tool for scoring similarity of signals directly in non-uniform sampling grids.

Описание языковых явлений: факты и артефакты (на материале веб-версии базы данных «Языки мира» ИЯз РАН)

The article examines the possibilities of specific language phenomena presentation and the causes of inaccuracies when transferring linguistic data from the encyclopedia edition "Languages of the World" to the web-version of the "Languages of the World" typological da-tabase. The material is intended for those interested in linguistic typology, data formalization and the development of linguotypological databases.

Analysis of the impact of prototyping‐related parasitic effects in a hybridGaNpower amplifier for5G FR1applications

AbstractThis article analyses the impact of parasitic effects encountered in the manufacturing of a Gallium Nitride power amplifier optimized for a specific trade‐off of efficiency and linearity at 5G FR1 frequencies. The analysis focuses on an example based on a packaged transistor and implemented in hybrid technology, adopting a two‐layer printed circuit board for passive distributed elements and surface‐mount lumped components. The design is summarized, and the focus is then posed on the comparison of simulated and measured results, the main causes of inaccuracy in their agreement, and a simple way of reproducing these in simulation. The mechanical stability of the assembly and the sensitivity of the second harmonic control are identified as the main sources of performance degradation. These effects are correctly modeled at the simulation level thanks to the insertion of specific parasitic lumped elements but could not be fully eliminated at the experimental level in this specific prototype. However, post‐tuning performed on the prototype, guided by the proposed analysis, still allows to reach satisfactory performance although somewhat sub‐optimal compared to the one expected from simulations. At 3.5 GHz, the re‐tuned PA demonstrates a measured output power in excess of 37.5 dBm at saturation, with associated gain higher than 14 dB and PAE of 60%. In a 2‐tone test with 20 MHz spacing, the IMD3 remains lower than −30 dBc up to 29 dBm of output power with a corresponding PAE of the order of 32%.

Sources of Inaccuracy in Boron Isotope Measurement Using LA‐MC‐ICP‐MS

Laser ablation multi‐collector‐inductively coupled plasma‐mass spectrometry (LA‐MC‐ICP‐MS) has become a valuable tool for the in situ measurement of the boron isotope composition of geological samples at high (tens to hundreds of μm) spatial resolution. That said, this application suffers from significant analytical challenges. We focus in this study on the underlying processes of two of the main causes for inaccuracies using this technique. We provide empirical evidence that not only Ca ions (Sadekov et al. 2019, Standish et al. 2019, Evans et al. 2021) but also Ar ions, that are reflected within the flight tube of the mass spectrometer, are the source for previously reported issues with spectral baselines. We also address the impact of plasma conditions on the instrumental mass fractionation as a source for matrix‐ and mass‐load‐related analytical biases. Comparing experimental data with the results of a dedicated release and diffusion model (RDM) we estimate that a close to complete (~ 97%) release of boron from the sample aerosol is needed to allow for consistently accurate LA boron isotope measurement results without the need for corrections.

Metrological Aspects of Assessing Surface Topography and Machining Accuracy in Diagnostics of Grinding Processes

The paper presents probabilistic aspects of diagnostics of grinding processes with consideration of metrological aspects of evaluation of topography of machined surfaces and selected problems of assessment of machining accuracy. The processes of creating the geometric structure of the ground surface are described. It was pointed out that the distribution of features important for process diagnostics depends on the mechanism of cumulative effects of random disturbances. Usually, there is a multiplicative mechanism or an additive mechanism of the component vectors of relative displacements of the tool and workpiece. The paper describes a method for determining the classification ability of specific parameters used to evaluate stereometric features of ground surfaces. It is shown that the ability to differentiate the geometric structure of a certain set of surfaces using a selected parameter depends on the geometric mean of the differences in normalized and sorted, consecutive values of this parameter. A methodology is presented for evaluating the ability of various parameters to distinguish different geometric structures of surfaces. Further, on the basis of analyses of a number of grinding processes, a methodology was formulated for proceeding leading to a comprehensive evaluation of machining accuracy and forecasting its results. It was taken into account that in forecasting the accuracy of grinding, it is necessary to determine the deviations, arising under the conditions of multiplicative interaction of the effects of various causes of inaccuracy. Examples are given of processes in which, due to the deformation of the technological system, dependent on the position of the zone and machining force, varying temperature fields and tool wear, the distributions of dimensional deviations are not the realization of stationary processes. It was emphasized that on the basis of the characteristics of the dispersion of the deviation value in the sum set of elements, it is not possible to infer its causes. Only the determination of the "instantaneous" values of the deviation dispersion parameters allows a more complete diagnosis of the process.

Single 24-GHz FMCW Radar-Based Indoor Device-Free Human Localization and Posture Sensing With CNN

The position information and posture information of a device-free human in a confined indoor environment have multiple uses in health monitoring and other areas. In this study, we aim to use a single-input-single-output (SISO) frequency-modulated continuous-wave (FMCW) radar at 24-GHz band for simultaneous localization and posture estimation of one device-free human target. This device is easy to deploy in new setups. We use image formation to convert temporal measurements of the radar signal into image-like data and convert the problem of simultaneous position estimation and posture perception into an image classification problem. Leveraging the use of convolutional neural networks (CNNs) for image classification, we design a variety of tests to explore the most favorable parameters of the CNN model and then use the best practice model to accomplish the classification task involving a fusion of localization and pose recognition. To explain the primary causes of inaccuracies, we examine not only cases based on a fused position and posture dataset but also cases based on position-only and posture-only datasets. On both real-life datasets, our proposed scheme can achieve 98% classification accuracy and less than 1-m localization accuracy within 0.95 cumulative error probability within the area of interest, outperforming traditional classification methods.

Investigation on the Temperature Distribution Uniformity of an Extrusion-Based 3D Print Head and Its Temperature Control Strategy

Extrusion-based 3D printing for thermoplastic polymers manifests potential for the fabrication of biocompatible and biodegradable scaffolds. However, the uncontrollable shape of printed filaments usually negatively impacts on the printing processes. Non-uniform temperature in the print head is a primary cause of inaccuracy in the diameter of filaments formed during the process of extruding thermoplastic polymers. Therefore, the temperature distribution inside the print head must be controlled accurately. This study developed a novel print head configuration with two groups of controllable heat sources for extrusion-based printing of thermoplastic polymers. Subsequently, a numerical thermal analysis based on the finite element method (FEM) was conducted to investigate the temperature field in the print head during the heating process. Moreover, a temperature control strategy is proposed under which the temperature distribution of the print head can be regulated. The temperature uniformity can be improved with the proposed temperature control strategy. Lastly, groups of printing trials were implemented, and the printed filaments showed excellent uniformity of diameter when temperature distribution uniformity was controlled in the print head.

Perceptions and Inaccuracy in New-Venture Investment Decision: An Experimental Evidence

Access to investment has a significant effect on performance of new-venture but investment decisions in such new-ventures are found to be inaccurate. Mainly researchers focused on the factors that are significant in determining investment decisions but no study has explored the cause of inaccuracy in new-venture investment decisions. We have used the theories of decision making and behavioral experiments to explore the cause of such inaccuracy. We have explored the role of information signals in determining perception, then measured the deviation between perceived utility and actual investment, and lastly explored the source of such deviation. In study-1, we asked participants to appraise proposals on prospects of “risk-exposure” and “return-potential”. In study-2, participants invest in the same proposals presented in random order. We found that the role of information in determining perception of “risk-exposure” and “return-potential” is partially mutually exclusive and partially related. Though information signals help in determining the perceptions, the investment decisions do not follow the rational value of the perceived utility. Time-constraints resulted in heuristics as only few information signals were considered in determining the same level of perceptions. Further, quick decisions limit the perspective of considering an information signal. As a result, information type, respective perceptions and time-constraints are found to be significant determinants of accuracy of investment decisions.

A service evaluation of the accuracy of electronic prescriptions used to calculate nebulised medication adherence in adult with cystic fibrosis

Adherence to nebulised medications in people with cystic fibrosis (CF) is known to be suboptimal. CFHealthHub uses an electronic prescription (e-prescription) as a denominator and chipped nebuliser devices which capture the frequency of nebulised medications inhaled by the patient. This enables a calculation of nebulised medication adherence to be made. However, e-prescriptions may contain errors which can affect the adherence calculation. This service evaluation sought to review the accuracy of CFHealthHub e-prescriptions at a single adult CF centre, to understand the nature and causes of any inaccuracies and to evaluate the effect of prescription complexity on prescription accuracy. A total of thirty e-prescriptions from CFHealthHub were compared to ‘gold standard’ prescriptions. Inaccuracies and types of error in the e-prescriptions were recorded and analysis was conducted to understand the effect of prescription complexity on this. The two prescriptions were discussed with participants to determine the causes of inaccuracies. Inaccuracies were found in 43% (13/30) of e-prescriptions and were significantly associated with alternating medication regimens (p = 0.025). There were four error types found within the e-prescriptions: inaccurate medication list, incorrect medication duration, incorrect medication frequency and prescription duplication errors. Medication list errors were significantly associated with alternating medication regimens (p = 0.007). Causes of e-prescription inaccuracy were due to failure to update the prescription following a change, errors in prescription entry and inaccuracies caused by using two different nebuliser devices. CFHealthHub e-prescriptions contain inaccuracies and prescription complexity can increase the risk of prescription inaccuracy, although the small sample size limits the ability of the service evaluation to draw strong conclusions. Causes of e-prescription accuracy should be addressed by the local CF team.

MeerKAT Primary-beam Measurements in the L Band

Abstract Full-polarization primary-beam patterns of MeerKAT antennas have been measured in the L band (856–1711MHz) by means of radio holography using celestial targets. This paper presents the observed frequency-dependent properties of these beams and guides users of this 64 antenna radio telescope that are concerned by its direction-dependent polarization effects. In this work, the effects on the primary beams due to modeling simplifications, bandwidth averaging, gravitational loading, and ambient temperature are quantified within the half-power region of the beam. A perspective is provided on the level of significance of typical use case effects. It is shown that antenna pointing is a leading cause of inaccuracy for telescope users in the presumed beam shape, introducing errors exceeding 1% in power near the half-power point of beams, owing to a telescope pointing accuracy of σ ≈ 0.′6. Disregarding these pointing errors, variability in the Stokes I beam shape relative to the array average is most commonly around 0.3% in power; however, the impact above 1500 MHz is on average triple that of the lower half of the band. This happens because the proportion of higher-order waveguide modes that are activated and propagate is sensitive to small manufacturing differences in the orthomode transducer for each receiver. Primary-beam correction verification test results for an off-axis spectral-index measurement experiment are included.

Modeling the systematic behavior at the micro and nano length scales

The assessment of the systematic behavior based on frequentist statistics was analyzed in the context of micro/nano metrology. The proposed method is in agreement with the well-known GUM recommendations. The investigation assessed three different case studies with definition of model equations and establishment of the traceability. The systematic behavior was modeled in Sq roughness parameters and step height measurements obtained from different types of optical microscopes, and in comparison with a calibrated contact instrument. The sequence of case studies demonstrated the applicability of the method to micrographs when their elements are averaged. Moreover, a number of influence factors, which are typical causes of inaccuracy at the micro and nano length scales, were analyzed in relation to the correction of the systematic behavior, viz. the amount of repeated measurements, the time sequence of the acquired micrographs and the instrument-operator chain. The possibility of applying the method individually to the elements of the micrographs was instead proven not convenient and too onerous for the industry. Eventually, the method was also examined against the framework of the metrological characteristics defined in ISO 25 178-600 with hints on possible future developments.

Spinal alignment shift between supine and prone CT imaging occurs frequently and regardless of the anatomic region, risk factors, or pathology

Computer-assisted spine surgery based on preoperative CT imaging may be hampered by sagittal alignment shifts due to an intraoperative switch from supine to prone. In the present study, we systematically analyzed the occurrence and pattern of sagittal spinal alignment shift between corresponding preoperative (supine) and intraoperative (prone) CT imaging in patients that underwent navigated posterior instrumentation between 2014 and 2017. Sagittal alignment across the levels of instrumentation was determined according to the C2 fracture gap (C2-F) and C2 translation (C2-T) in odontoid type 2 fractures, next to the modified Cobb angle (CA), plumbline (PL), and translation (T) in subaxial pathologies. One-hundred and twenty-one patients (C1/C2: n = 17; C3-S1: n = 104) with degenerative (39/121; 32%), oncologic (35/121; 29%), traumatic (34/121; 28%), or infectious (13/121; 11%) pathologies were identified. In the subaxial spine, significant shift occurred in 104/104 (100%) cases (CA: *p = .044; T: *p = .021) compared to only 10/17 (59%) cases that exhibited shift at the C1/C2 level (C2-F: **p = .002; C2-T: *p < .016). The degree of shift was not affected by the anatomic region or pathology but significantly greater in cases with an instrumentation length > 5 segments (“∆PL > 5 segments”: 4.5 ± 1.8 mm; “∆PL ≤ 5 segments”: 2 ± 0.6 mm; *p = .013) or in revision surgery with pre-existing instrumentation (“∆PL presence”: 5 ± 2.6 mm; “∆PL absence”: 2.4 ± 0.7 mm; **p = .007). Interestingly, typical morphological instability risk factors did not influence the degree of shift. In conclusion, intraoperative spinal alignment shift due to a change in patient position should be considered as a cause for inaccuracy during computer-assisted spine surgery and when correcting spinal alignment according to parameters that were planned in other patient positions.

Study on the Causes of Inaccuracy of Qibla Direction of the Great Mosque Baitul Makmur West Aceh

The accuracy of the Qibla direction at the Baitul Makmur Great Mosque in West Aceh cannot tolerate. The reason is that the value of deviation is so high that it does not face ainul ka'bah or even jihatul ka'bah. This Qiblah direction is not by the minimum limit of tolerance for the variation of the Qibla direction and is not by the Islamic legal status. This study examines the causes of the inaccuracy of the Qibla of the Great Mosque of Baitul Makmur Meulaboh West Aceh, namely the lack of role of figures and efforts to maintain the architecture of the mosque building. This research belongs to qualitative field research, by verifying the direction of the Qiblah with the rashdul qibla method and google earth observation to explore causes of inaccuracy. Interview techniques are also used to obtain in-depth field data. The analysis technique used is descriptive analysis. This study indicates that the inaccuracy of the Qibla direction of the Baitul Makmur Great Mosque in West Aceh is inseparable from the minor role of religious figures and leaders at the beginning of the Mosque's construction. Until now, the direction of the Mosque's Qiblah is still parallel to the mihrab. Renovations were also not carried out because of maintaining the architecture of the mosque building. Renovation of the mosque building to calibrate the Qibla direction would reduce the aesthetics of the mosque building.

Evaluating the Performance of sUAS Photogrammetry with PPK Positioning for Infrastructure Mapping

Traditional acquisition methods for generating digital surface models (DSMs) of infrastructure are either low resolution and slow (total station-based methods) or expensive (LiDAR). By contrast, photogrammetric methods have recently received attention due to their ability to generate dense 3D models quickly for low cost. However, existing frameworks often utilize many manually measured control points, require a permanent RTK/PPK reference station, or yield a reconstruction accuracy too poor to be useful in many applications. In addition, the causes of inaccuracy in photogrammetric imagery are complex and sometimes not well understood. In this study, a small unmanned aerial system (sUAS) was used to rapidly image a relatively even, 1 ha ground surface. Model accuracy was investigated to determine the importance of ground control point (GCP) count and differential GNSS base station type. Results generally showed the best performance for tests using five or more GCPs or when a Continuously Operating Reference Station (CORS) was used, with vertical root mean square errors of 0.026 and 0.027 m in these cases. However, accuracy outputs generally met comparable published results in the literature, demonstrating the viability of analyses relying solely on a temporary local base with a one hour dwell time and no GCPs.

Evaluating and improving the reliability of the UV-persulfate method for the determination of TOC/DOC in surface waters

The UV-persulfate oxidation method is widely used for determining the total organic carbon concentration of aqueous samples (denoted for convenience as UVP-TOC). However, for some surface water samples, the measurement of TOC by this method can be unreliable, deviating significantly from the true carbon content. In this study, the performance of the UVP-TOC method has been investigated by comparing the results from the analysis of a variety of aqueous samples that included two kinds of surface water samples and related surface water model substances: bovine serum albumin (BSA), sodium alginate (SA), humic acid (HA), tannic acid (TA), benzoic acid (BA) and citric acid (CA), with those from a high-temperature combustion method (elemental analysis); the latter providing the true carbon content value. By comparing the above data, it was found that the UVP-TOC method significantly underestimated the TOC value of the surface water samples, and it was also found that the model components BSA (protein) and HA (humic substances, HS) had a substantial influence on the TOC underestimation, while the SA (polysaccharide), TA (complex organic molecule) and CA/BA (small molecules) had little effect. The results showed that the agglomeration within and between BSA and HA molecules was an important reason for the inaccurate UVP-TOC values of BSA and HA. A further limitation was that for BSA, surfactants (e.g. sodium dodecylbenzene sulfonate, SDBS) and other surfactant-like substances, foam was formed during the CO2 removal purging process by N2 that seriously interfered with the determination of TOC. The study provides new information and insight into the causes of inaccuracies in the UVP-TOC analysis of surface waters and possible approaches to improve the accuracy.