Sources Of Error Research Articles

Theoretical analysis and simulation verification for measuring the geometric distances between the silicon spheres with the laser interferometer in G measurement

Abstract The Newtonian gravitational constant G is one of the most fundamental constants in nature. In the measurement of G with the angular acceleration feedback (AAF) method, the largest error comes from the distances between the geometric centers (GC) of the source masses. In the on-going experiment, the silicon spheres with a more homogeneous density are used as the source masses. Here a scheme of measuring the GC distances between the silicon spheres with the laser interferometer is proposed. The measurement principle is analyzed in detail, and the error sources, such as the laser, the sphere, the alignment of optical path, and the environment are evaluated in detail. With this method, the horizontal and vertical GC distances can be measured with uncertainties of 11 nm and 9 nm, respectively. The simulation with the ZEMAX software is performed to verify the theoretical model of measuring the GC distance, where the maximum deviation of the distance between the simulation result and the theoretical one is only -2.7 nm. When the sphericities of the four silicon spheres are at the level of 0.1 m, the uncertainty of each GC distance after considering the sphericity is about 0.1 m, corresponds to a combined uncertainty of 0.6 ppm for the G measurement with the AAF method. This provides an effective method to reduce the measurement uncertainty of GC distance, and makes it possible to measure G with a higher precision.

Coverage matters: identifying and mitigating sampling frame issues in recreational fishing surveys

Abstract Surveys play an integral part in monitoring and maintaining sustainable recreational fisheries. For any probabilistic survey, the selection of a sampling frame (e.g., list of individuals or fishers) is an important decision because it influences the ability to provide unbiased estimates of recreational catch and effort. Undercoverage occurs when units of the target population (i.e., the population of interest) are missing from the frame population. This error can undermine the reliability of research advice generated from survey estimates. In this review, we: (i) define six sampling frame configurations that are commonly applied in probabilistic recreational fishing surveys; (ii) synthesise how coverage errors associated with each configuration have been addressed for marine recreational fisheries globally; (iii) outline approaches to identify and correct for coverage errors; and (iv) recommend how to future-proof coverage issues. In our six case studies, multiple types of undercoverage were identified and addressed to varying extents, depending on the characteristics of each fishery and type of sampling frame used. Generalised list frames (particularly phone lists) are arguably the most prone to undercoverage error. To assist in future-proofing surveys, we recommend: (1) considering coverage error during survey planning; (2) designing pilot surveys or scheduling concurrent surveys to evaluate and/or correct for potential bias; (3) recognising that coverage error often changes through time; (4) using technological or multi-frame approaches to mitigate coverage error; (5) considering model-based survey tools to correct for undercoverage; and (6) documenting the sampling frame and potential sources of coverage error in publications. These recommendations extend to inland recreational fisheries, commercial fishing surveys and fisheries-independent surveys. Graphical abstract

Calibration-free feedforward temperature compensation for wireless clock synchronisation

Wireless systems are entering the arena of time-critical applications, including industrial controls. This makes clock synchronisation vital. A relevant source of synchronisation errors, especially in heavy-duty applications and harsh environments, is given by temperature variations that affect the quartz oscillators. This paper takes a control theory-based approach and proposes to augment clock synchronisation schemes – that are typically feedback-based – with a feedforward compensation path using temperature measurements to quickly react to temperature change. Unlike previous approaches relying on per-device data, our solution takes advantage of the combined feedforward-feedback nature of the control scheme to perform compensation using only nominal crystal parameters. When implemented in conjunction with the FLOPSYNC-2 feedback-based clock synchronisation scheme and tested both in simulation and experimentally, the approach resulted in a greatly reduced synchronisation error during temperature transients. In detail, Monte Carlo simulations show that the proposed solution can reduce the peak clock synchronisation error on average by 5.3 \(\times\) and in the worst case by 2.2 \(\times\) , thus proving applicable and effective without the need for a costly per-device calibration. When tested experimentally on a network of sensor nodes, a 3.3 \(\times\) peak clock synchronisation error improvement was observed, confirming the simulation predictions.

Inter-Observer Processing and Measurement Error Are Low for 2D Dental Measurements on Shared microCT Scans.

Sharing micro-computed tomographic (μCT) scans of teeth increases data accessibility and reduces the need for repeated scans of any given specimen. However, the use of the same TIFF stacks or DICOMs by multiple individuals has the potential to introduce new sources of error. Here, we explore whether use of the same μCT scans by different persons produces comparable results. Worn (N = 11) and unworn (N = 4) Cercocebus atys upper molars (UM1 N = 8, UM2 N = 7) were μCT scanned using a Bruker Skyscan 1172 High Resolution ExVivo Scanner at a resolution of 22 μm. Two individuals (K.N.G. and M.C.O.) created a 2D mesial slice for each TIFF stack (tooth). Worn teeth were reconstructed by K.N.G. and M.C.O. Three researchers (M.C.O., K.N.G., and J.R.) measured tooth shape, linear enamel thickness, average enamel thickness, and relative enamel thickness (AET and RET). Inter-observer percent error was calculated for each measurement. Univariate ANOVAs were calculated to evaluate variance due to slice maker, reconstructor, tooth, and measurer when percent error averaged > 5%. For unworn teeth, error was generally low and largely due to the person doing the measurement. For worn teeth, wear reconstructor was a statistically significant source of variation for AET and RET. We found that (1) inter-observer error was generally low, (2) linear measurements are prone to error, (3) worn teeth did not present an additional source of error as compared to unworn teeth, and (4) different people can use the same μCT scans to reliably reconstruct, slice, and measure teeth.

Treatment experiences and decision-making among patients with metastatic colorectal cancer: Results of an online US patient survey.

80 Background: Developing treatment plans for patients (pts) with metastatic colorectal cancer (mCRC) is complex. Using an online survey, we aimed to understand the treatment experience of pts with mCRC, including pt involvement in treatment decision-making. Methods: Adults (≥18 yrs) with mCRC took part in an online survey conducted in the US by The Harris Poll between Jan 17 and Feb 7, 2024. Of 344 respondents, 90 were recruited from patient advocacy groups (PAGs). The 60-question survey explored pts’ experience of mCRC. We report results from questions focused on treatment. Raw data were not weighted and are only representative of the participants. All surveys are subject to sources of error. Results: Of 256/344 pts who received mCRC treatment, chemotherapy and surgery were the most common therapies(Table). Among pts who received therapy, 67% reported their ability to take treatment was impacted by non-medical factors such as finances or mental health. Overall, 58% of pts have had to decide between affording treatment or meeting basic needs, e.g. safe housing, food, transportation, especially Black and Hispanic pts (Table). Of all 344 pts, 87% reported reliance on their healthcare provider (HCP) when making treatment decisions, primarily their oncology surgeon (48%) or oncologist (45%), despite 268 (78%) pts carrying out independent research on new treatments or clinical trials. Although 266 pts (77%) were involved in treatment decision making, 231 pts (67%) wished for more power in the process. Overall, 64 pts (19%) wished for more support from PAGs during treatment, while 59 pts (17%) relied on PAGs to help guide treatment decisions. The most common factors affecting pt treatment decisions related to costs or insurance coverage (52%), impacts on physical health and quality of life (each 39%), fear of being a burden on family (35%), and side effects (32%). Conclusions: Pts with mCRC rely on their HCPs when making treatment decisions and wish for more power in the process. Personal finance and insurance coverage play dominant roles in treatment for mCRC. PAGs are an important resource for treatment information that are underutilized. Treatment experience of pts with mCRC in an online US survey. n (%) All pts N=344 Black pts n=87 c Hispanic pts n=75 c White pts n=158 Received treatment 256 (74) 52 (60) 60 (80) 129 (82) Chemotherapy a 169 (66) 23 (44) 33 (55) 104 (81) Surgery a 147 (57) 23 (44) 32 (53) 86 (67) Radiotherapy a 101 (39) 25 (48) 15 (25) 52 (40) Immunotherapy a 72 (28) 16 (31) 20 (33) 30 (23) Targeted therapy a 61 (24) 12 (23) 14 (23) 30 (23) Other a 13 (5) 0 0 12 (9) Stopped treatment due to overall burden a ,b 92 (36) 28 (54) 33 (55) 27 (21) Had to decide between treatment or basic needs 198 (58) 60 (69) 52 (69) 69 (44) a Among pts who received treatment. b Financial impact, quality of life, etc. c Base size <100 pts; interpret results directionally.

A novel multi-stage precision reliability assessment method for mechanical system by Bayesian fusion

Precision reliability is crucial for evaluating mechanical system performance. However, limited data makes reliability assessment challenging due to difficult data collection and small sample sizes. Currently, little research has focused on using initial theoretical models as prior information for reliability assessment. This paper proposes a multi-stage precision reliability assessment method for a mechanical system by Bayesian fusion, which can effectively integrate design phase models with usage phase data under limited data conditions to carry out reliability assessment. First, the mechanical system is divided into meta-action units for precision modeling during the design phase. Then, an initial theoretical precision model is developed by incorporating operational error sources. Next, initial theoretical precision model is used to fit the Wiener process-driven model as Bayesian prior information, and reliability assessment is evaluated under different distribution assumptions for both the prior information and experimental data. This approach combines the prior advantages of the theoretical model with the data processing ability of the data-driven model under no prior data and small sample sizes, improving assessment precision and interpretability. Finally, a case study on a machine tool rotary table system validates the effectiveness of this method.

Outcomes of Zero Power Intraocular Lenses: Insights into the Keratometric Index and Axial Length.

We analyzed intraocular lens (IOL) power calculation in a series of patients with a zero diopter power implant. The idea was to bypass the Estimated Lens Plane (ELP), an important variable in normal IOL calculation. Large multi-center group practice. Retrospective, observational study. A consecutive series of patients undergoing cataract surgery after optical biometry and implantation of a zero (0.0 D) power IOL were studied. Complete biometry was performed with an optical low coherence optical biometer. The predicted refraction was calculated with and without recalibrating the axial length (AL) using a Sum-Of-Segments (SOS) approach with the Hoffer Q, Holladay 1, SRK/T, Haigis, Barrett Universal II, and Olsen formulas. A ray tracing model to back-calculate the corneal power from the observed postoperative refraction and AL was also included. In 52 eyes of 52 patients, mean prediction errors for the Hoffer Q, Holladay 1, SRK/T, Haigis, Barrett Universal II, and the Olsen formulas were +1.48, +1.15, +0.91, +0.65, +0.15 and +0.11 D respectively using standard AL and after SOS correction of the AL the mean errors changed to +1.08, +0.75, +0.52, +0.26, -0.25, and -0.27 D respectively. The mean back-calculated corneal power was 1.25 D lower than the mean keratometer reading using the standard keratometric index of 1.3375 and corresponded to an effective index of 1.328. The hyperopic error commonly seen in highly myopic eyes with classical thin-lens formulas is only partly corrected by SOS recalibration of the AL. We suggest the source of the residual error is an incorrect keratometric index.

Determination of Diffraction Elastic Constants Using the Maximum Entropy Method

X-ray diffraction methods are an established technique to analyze residual stresses in polycrystalline materials. Using diffraction, lattice plane distances are measured, from which residual stresses can be calculated by using diffraction elastic constants which can be inferred from experimental measurements or calculated based on micromechanical model assumptions. We consider two different generalizations of existing micromechanical models for the case of texture-free, i.e. statistically isotropic, single-phase polycrystals. The first is based on the singular approximation method of classical micromechanics, from which existing Voigt, Reuss, Hashin-Shtrikman and self-consistent methods are recovered. The second approach, which is newly proposed in this work, is based on the micromechanical Maximum Entropy Method. Both approaches are applied to the problem of calculating diffraction elastic constants of texture-free cubic polycrystals and are found to be consistent with each other in that case. Full-field FFT simulations are used to validate the analytical models by simulating X-ray diffraction measurements of copper. In the simulative setting, many sources of experimental measurement error are not present, which results in a particularly accurate validation of theoretical bounds and approximations. The first core result of the paper is a formulation of diffraction elastic constants for texture-free polycrystals in terms of the macroscopically measurable effective shear modulus. These diffraction elastic constants can be adapted to the properties of a given material sample. The second core result is the validation of the Maximum Entropy Method for X-ray diffraction stress analysis of texture-free single-phase materials as a preliminary step before extending the method to textured and multi-phase materials.

The solar system Fe/Mg ratio

AbstractSolar wind Fe and Mg fluences (atoms/cm2) were measured from Genesis collectors. Fe and Mg have similar first ionization potentials and solar wind Fe/Mg should equal the solar ratio. Solar wind Fe/Mg is a more valid measure of solar composition than CI chondrites and can be measured more accurately than spectroscopic photospheric abundances. Mg and Fe fluences analyzed in four laboratories give satisfactory agreement. Si and diamond‐like carbon collector fluences agree for both elements. The Mg and Fe fluences are 1.731 ± 0.073 × 1012 and 1.366 ± 0.058 × 1012 atoms/cm2. All plausible sources of errors down to the 1% level are documented. Our value for the solar system Fe/Mg, 0.789 ± 0.048 agrees within 1 sigma errors with CI chondrites, spectroscopic photospheric abundances, and with the solar wind data from the ACE spacecraft. CI samples from asteroid Ryugu give Fe/Mg in agreement with Genesis and meteoritic CI samples despite very small sample sizes. The higher accuracy of the Genesis solar Fe/Mg permits a comparison with chondritic Fe/Mg at the 10% level. Intermeteorite Fe/Mg averages differ among the main C chondrite groups but are within, or very close to, the ±1 sigma Genesis solar Fe/Mg.

An examination of noun and verb naming differences in aphasia: effects of lesion site, aphasia type and the use of static or dynamic stimuli

ABSTRACT Background Anomia has been extensively researched within the aphasia literature and a dissociation in naming nouns and verbs has been used in diagnostic classifications and related to lesion location. However, there is evidence that action naming is more difficult for many clinical populations as well as for healthy speakers. Confrontation naming tests have often been used to evaluate anomia, but static depiction has been considered a potential source of error in evaluations of verb naming, since actions are dynamic. Aims The first aim of this study was to examine the ability to name objects and actions in a stroke population and non-brain damaged controls and to explore naming ability in relation to lesion location and aphasia type (fluent or non-fluent). A second aim was to determine if action naming is facilitated by using dynamic rather than static stimuli. Methods & Procedures A cross-sectional study was carried out, where 19 participants with aphasia after stroke and 19 matched controls were included. Type of aphasia was based on connected speech samples. Naming performance was compared on two Swedish naming tests consisting of line drawings of high frequency nouns and verbs respectively, and a subset of action pictures was compared to a test using video depictions of actions as verb stimuli. Outcomes & Results There was a significant difference between nouns and verbs in 11 of 19 participants with aphasia. Only one participant, with a temporo-occipital lesion, had a substantial noun-verb difference (≥30%). Individual results showed some agreement with the fluent-nonfluent classification. However, at group level, there was no significant difference between scores on action and object naming for participants with aphasia. While only the control group achieved significantly higher scores on object than action naming, response latencies were longer for action than object naming for both groups. There was no difference in action naming performance that could be related to the use of dynamic or static stimuli. Conclusions The results suggest that a dissociation in naming nouns and verbs is common in aphasia. This finding underscores the importance of testing action as well as object naming. Even though there was some agreement with aphasia type, the relationship between noun-verb dissociation, lesion location and aphasia type is not straight forward. The study adds to previous findings suggesting that action naming is more difficult than object naming. The question whether action naming is facilitated by using dynamic stimuli needs to be further investigated.

Characterization of highly focused vector fields using phase retrieval: a practical guide

Experimentally measuring the longitudinal component of a highly focused electromagnetic field is challenging, especially when using near-field technology methods. We recently demonstrated that this component can be estimated by combining optical and numerical techniques. This method involves determining the complex amplitude of the transverse field in the focal region using phase retrieval techniques. Subsequently, the field is numerically propagated, and the longitudinal component is estimated using Gauss’s theorem. This Application Note discusses the experimental details and potential sources of error that could affect the results. Additionally, we introduce a graphical application that streamlines the process and helps in selecting appropriate parameters to achieve satisfactory outcomes.

Study of the thermolysis process of copper (II) sulfate pentahydrate by thermovolumometric method

When studying mixtures of minerals, composites of complex composition, and selecting powder catalysts, problems often arise for which the small masses of samples used in thermogravimetry do not provide sample representativeness. This requires the use of other methods of analysis that allow the use of samples ten times larger in mass. The paper presents the results of a study of the thermolysis process of copper (II) sulfate pentahydrate using a thermovolumometric method. During the tests, a sealed container with the analyzed substance and a thermoelectric converter was placed in a tubular furnace. The gas released during thermolysis entered the bubbling tank through the capillary. SoundForge13 and TableCurve 2D programs were used to process experimental data. The sources of error in the thermovolumometric analysis technique are analyzed. Dependencies that can be used to improve its accuracy are given. It was revealed that the value of the repeatability index obtained as a result of assessing the repeatability of the method is 3 °C; in the range of densities of the evolved gases 1. 25 – 1. 43 kg/m3, the resolution of the method in terms of the mass of the substance is 12 – 13 μg. The results obtained can be used to determine the temperatures of phase transitions when studying processes occurring during heating of mineral compositions, as well as the temperatures of decomposition reactions of substances. The accuracy of measurements can be increased by careful sample preparation, reducing the heating rate of the sample and introducing corrections to the measurement result based on the obtained dependencies.

Model and mesh selection from a mCRE functional in the context of parameter identification with full-field measurements

Abstract In this paper, we propose a general deterministic framework to question the relevance, assess the quality, and ultimately choose the features (in terms of model class and discretization mesh) of the employed computational mechanics model when performing parameter identification. The goal is to exploit both modeling and data at best, with optimized model accuracy and computational cost governed by the richness of available experimental information. Using the modified Constitutive Relation Error concept based on reliability of information and the construction of optimal admissible fields, we define rigorous quantitative error indicators that point out individual sources of error contained in the identified computational model with regards to (noisy) observations. An associated adaptive strategy is then proposed to automatically select, among a hierarchical list with increasing complexity, some parameterized mathematical model and finite element mesh which are consistent with the content of experimental data. In addition, the approach is computationally enhanced by the complementary use of model reduction techniques and specific nonlinear solvers. We focus here on experimental information given by full-field kinematic measurements, e.g. obtained by means of digital image correlation techniques, even though the proposed strategy would also apply to sparser data. The performance of the approach is analyzed and validated on several numerical experiments dealing with anisotropic linear elasticity or nonlinear elastoplastic models, and using synthetic or real observations.

Incorporating Power-Law Model and ERA-5 Data for InSAR Tropospheric Delay Correction Analysis

InSAR technology effectively monitors urban subsidence and evaluates the stability of infrastructure across extensive regions. Atmospheric tropospheric delay constitutes a significant source of error that adversely impacts the accuracy of InSAR deformation measurements. The meteorological conditions in the highland basin region are complex, and there is a notable deficiency of sufficient sounding balloon observations. This study replaces the sounding balloon data in the power-law model with ERA-5 data (PLE5) to correct the InSAR atmosphere phase delay. This method was tested in Dali utilizing Sentinel-1 data. By comparing its performance against the GACOS model, traditional linear model, and ERA-5 correction, the PLE5 model exhibited the lowest phase standard deviation. This method provides an alternative approach for applying the power-law model in regions with limited sounding balloon data, enhancing the accuracy of InSAR tropospheric delay correction.

Volume and Mass Conservation in Lagrangian Meshfree Methods

ABSTRACTMeshfree Lagrangian frameworks for free surface flow simulations do not conserve fluid volume. Meshfree particle methods like SPH are not mimetic, in the sense that discrete mass conservation does not imply discrete volume conservation. On the other hand, meshfree collocation methods typically do not use any notion of mass. As a result, they are neither mass conservative nor volume conservative at the discrete level. In this paper, we give an overview of various sources of conservation errors across different meshfree methods. The present work focuses on one specific issue: inconsistent volume and mass definitions. We introduce the concept of representative masses and densities, which are essential for accurate post‐processing in meshfree collocation methods. Using these, we introduce an artificial compressibility in the fluid to reduce errors in volume conservation. Numerical experiments show that the introduced frameworks significantly improve volume conservation behaviour in meshfree collocation methods, even for complex industrial test cases such as automotive water crossing.

Improving MRI turbulence quantification by addressing the measurement errors caused by the derivatives of the turbulent velocity field - Sequence development and in-vitro validation.

To improve the current method for MRI turbulence quantification which is the intravoxel phase dispersion (IVPD) method. Turbulence is commonly characterized by the Reynolds stress tensor (RST) which describes the velocity covariance matrix. A major source for systematic errors in MRI is the sequence's sensitivity to the variance of the derivatives of velocity, such as the acceleration variance, which can lead to a substantial measurement bias. We developed a Cartesian phase contrast sequence with fast velocity encoding and two separately measured partial echoes with opposite readout directions. This design aims to reduce the high-order gradient moments that are responsible for the described measurement error. Velocity encoding directions follow the ICOSA6 scheme to capture the full RST. Turbulence data is reconstructed using the intra-voxel phase dispersion (IVPD) technique. We validated this sequence in vitro using a periodic hill flow benchmark with highly anisotropic turbulence. MRI data underwent extensive averaging, with multiple velocity encoding values employed to reduce noise and isolate systematic effects. The RST data obtained from the new sequence agree well with the ground truth. Compared to a state-of-the-art sequence, the maximum errors were reduced by factor five. Simple adjustments to current MRI protocols can greatly enhance turbulence measurement accuracy through the reduction of high-order gradient moments. The proposed measures include applying fast velocity encoding, high readout bandwidth, and a highly asymmetric readout. Ringing artifacts due to the asymmetric readout can be removed via a second, inverted readout.

Software solution for integration of frozen section quality assurance into daily practice.

Diagnoses rendered using the frozen section (FS) technique during surgical procedures are used to guide intraoperative decisions. Therefore, diagnostic FS errors have the potential to affect patient safety and quality of care. Diagnostic FS errors arise due to both technical and interpretative factors and present a challenge to surgical pathology laboratories to recognize, document, and manage in a timely fashion. Thus, there is a need to monitor discrepancies between FS and permanent diagnoses and effectively communicate with the clinical teams when an error is discovered to ensure an opportunity for timely interventions, if clinically indicated. Our FS practice is complex, with many contributing variables, such as a partially generalized FS pathology practice model among pathology faculty and/or surgeons with specific subspecialty expertise and different physical locations of FS facilities. We implemented a comprehensive frozen section quality assurance (FSQA) program using custom software solutions aimed at improving patient safety by monitoring recognition, increasing documentation, and facilitating communication in cases where there is a discordance between intraoperative and permanent diagnoses. Our FSQA program allows for categorizing frozen section discrepancies according to the source of error, such as interpretive vs technical errors, to understand how errors arise and todevelop appropriate mitigation strategies for reducing errors. Overall, our intervention to improve FSQA has engaged pathology faculty in a uniform and systematic manner, and our data show that our new FSQA program led to a markedly shortened time interval of FSQA, allowing for timely management and resolution of errors.

A method for calibrating robotic kinematic parameters based on a multi-error source model and an optimized measurement pose set

Purpose The purpose of this study is to improve the accuracy of industrial robot kinematic parameter identification and position accuracy by solving the problem of insufficient consideration of error sources in the kinematic parameter identification model and optimizing the selection of measurement pose set. Design/methodology/approach In this study, a kinematic calibration method for industrial robots considering multiple error sources is proposed. Based on the Modified Denavit Hartenberg (MD-H) model, a robot kinematics identification model including joint reduction ratio error, target ball installation error and coordinate system transformation error is established. Taking the optimal observability index O1 and the minimum flexible deformation as the optimization objectives, a measurement pose set optimization method based on Non-dominated Sorting Genetic Algorithm II (NSGA-II) is proposed to obtain a measurement pose set with higher identification accuracy. Findings Through experiments conducted with the Nantong Zhenkang ZK1400-6 robot as the test subject, the kinematic parameters identified by the optimized measurement pose set are more accurate than the randomly selected measurement pose set, and the positioning accuracy of the robot is improved from 2.11 to 0.31 mm, an increase of 85.3%. Originality/value This study introduces a position error model that comprehensively accounts for the error sources causing positioning inaccuracies. Building on this foundation, a novel flexible deformation index is proposed to quantify the flexible deformation in the measurement pose set, thereby reducing the impact of such deformation on the position error in the model. To the best of the authors’ knowledge, for the first time, this study presents an optimization method for the measurement pose set based on NSGA-II, using the flexible deformation index and observability index as objectives for multi-objective optimization, simultaneously optimizing the pose error and Jacobian matrix in the error model.

High-Accuracy Bandgap Reference of <20 ppm/∘C: A Review

This review discusses the principle of typical bandgap reference circuits and analyzes their sources of errors. In order to provide readers with a clear perspective, we categorize the error sources into four types: (a) amplifier offset; (b) high-order nonlinearity of VBE; (c) current mirror mismatch; and (d) other error sources. For these error sources, the most commonly used methods to reduce or minimize them to achieve high accuracy are summarized. Furthermore, this review explores sub-1V bandgap reference design techniques, addressing the increasing demand for low-power and low-voltage applications. Finally, we provide some suggestions for a future high-accuracy reference design.

Finding and minimizing systematic errors in dual-comb spectroscopy

Abstract With sufficiently high signal-to-noise, several systematic errors become prominent in dual-comb interferometry measurements. This paper reviews several error sources including electrical, photo-detection, amplification and acquisition chain non-linearity. Sources of optical non-linearity such as self-phase modulation, cross-phase modulation and Raman soliton shifting are also covered, as are spectral fringing due to parasitic reflections and back-scattering. The non- linear response of the target sample itself can also be a source of errors. Methods to identify and minimize errors in experimental data are discussed. Good practices, instrument design strategies and tools, such as the dynamic range diagram, are suggested.