Level Of Inaccuracy Research Articles

Научно-методический подход к разработке проектов опытно-промышленных испытаний открытой разработки месторождений

Methodology of designing pilot tests in open-pit mining is a complex and insufficiently developed issue in the theory and practice of designing mining systems, which, as a rule, fails to take into account the mining and geological features of the deposits. The complex development of mineral deposits requires new methods of open-pit designing. Thus, the theoretical justification and development of the methods to determine the optimal parameters and indicators of open-pits during the design of pilot tests with the establishment of scales, deadlines, tasks and test conditions is an urgent research problem. The authors of the study have systematized the research trends in developing the basis for designing pilot tests in open-pit geotechnology. The level of geological inaccuracies in case of insufficiently reliable prospecting results leads to a decrease in the expected technical and economic indicators of the mining project ranging from 5-20% to several folds. When information on the deposit is insufficient, pilot test projects are prepared. This is done in order to obtain additional input data for preparation of the feasibility study of permanent conditions or at the stage of the field development to verify the created technologies and means of their mechanisation in order to avoid revision of the mining system parameters in the course of the field operations due to discrepancies between the geomechanical and hydrogeological representations given in the detailed exploration materials and the real conditions.

Process development and validation of next generation 3D calibration standards for application in optical microscopy

Abstract A scalable wafer-based fabrication process for a new generation of 3D standards enabling the 3D calibration of optical microscopes is presented and validated. The 3D standards are based on step pyramids with several layers in the µm range and a system of cylindrical knops distributed across the layers as marks for coordinate based calibration. This enables calibration for the three coordinate axes and the orthogonality error between them in a single measurement step. The requirements necessary for such a calibration, as optical non-transparency, reproducible flatness of the pyramid step heights and the lowest possible deviations of the lateral marks coordinates, are met by optimizing the manufacturing process: The deviation of the height steps distributed over the wafer is ±3.6 nm and is primarily caused by the layer deposition processes. The lateral manufacturing accuracy was determined using calibrated scanning electron microscope (SEM) and show a mean deviation of 20 or 60 nm, depending on the lateral size of the structures. The electron beam lithography process and the level of inaccuracy of the SEM standard have an influence on the lateral scaling accuracy. Based on the tactilely generated height values and the coordinates of the mark determined by a calibrated SEM, an example calibration of a confocal laser scanning microscope was successfully performed and showed good conformity to conventional calibration techniques.

Impact of Solar Shading on Façades’ Surface Temperatures under Summer and Winter Conditions by IR Thermography

In warm climates with high levels of solar irradiation, solar shading plays a determinant role on buildings’ envelope performance, both during summer and winter conditions. In this research, an evaluation of the solar shading effect on sunny façades through IR thermography non-destructive testing was performed. Sunny and shaded areas revealed temperature differences of 7.4 °C in summer conditions and up to 1.2 °C in wintertime. Moreover, solar shading was shown to be beneficial not only for decreasing surface temperature in summertime but also for reducing convective air flow in wintertime. In addition, it was found that the prevalence of dense shadows, especially with non-reflective materials in louvres, is favorable. External Thermal Insulation Constructive Systems (ETICS) must be shadowed and the use of clear colors is recommended to reinforce homogeneity in the surface in wintertime and reduce solar absorptance in summertime. Under steady-state calculations, thermal losses can be reduced up to 30% at night in wintertime and up to 50–60% at daytime in summertime because of the shadowing. However, another important finding lied in the confirmation of the performance gap that arises between using air temperature, sol-air temperature and the actual surface temperature data, in such a way that the two former implied high levels of inaccuracy and overestimated the performance of the buildings compared to the actual behavior. Some of the main conclusions can be extrapolated to other circumstances.

Midpalatal miniscrew insertion: The accuracy of digital planning and surgical placement

The objective of this study was to investigate the accuracy of palatal miniscrew insertion, evaluating the effect of guide fabrication and surgical placement. Guided insertion of bilateral paramedian palatal miniscrews was undertaken using Appliance Designer software (3Shape, Copenhagen, Denmark). A resin surgical guide (PPro Surgical Guide; Straumann AG, Basel, Switzerland) was used. Superimposition of the miniscrew position relative to the digital design was undertaken using bespoke software (Inspect 3D module, OnyxCeph; Image Instruments GmbH, Chemnitz, Germany) to assess surgical inaccuracy. Miniscrew position relative to the surgical guide was also assessed to isolate the effect of planning inaccuracies. Both horizontal and vertical discrepancies were evaluated at both implant locations. Twenty-seven patients having bilateral palatal insertions were examined. Mean discrepancies were<0.5 mm, both in the horizontal and vertical planes. The mean overall horizontal and vertical discrepancy between the digital design and final miniscrew position on the left side was 0.32 ± 0.15 mm and 0.34 ± 0.17 mm, respectively. The maximum horizontal discrepancy observed was 0.72 mm. No significant differences were observed in relation to the accuracy of mini-implant positioning on the basis of sidedness, either for horizontal (P= 0.29) or vertical (P= 0.86) discrepancy. High levels of accuracy associated with guided insertion of paramedian palatal implants were recorded with mean discrepancies of less than 0.5 mm both in the horizontal and vertical planes. No difference in accuracy was noted between the left and right sides. Very minor levels of inaccuracy associated both with surgical techniques and surgical guide fabrication were recorded.

Does Schooling Increase Political Belief Accuracy?

Citizens must hold accurate beliefs about politically relevant facts to preserve democratic representation, accountability and legislation. We theorize that, abstracting from one’s background, schooling per se does not trigger the epistemological sophistication that is necessary to get a grasp of the political world. In this article, we study whether schooling improves the accuracy of factual beliefs about the share of foreigners and unemployed, later in life. We derive an appealing metric of belief accuracy, matching survey respondents’ beliefs with the corresponding real-world datum at the time of the interview in their country, retrieving high levels of inaccuracy in both issues. More educated individuals display higher belief accuracy, most likely due to selection, rather than causality: compelling otherwise-dropouts to stay in school by extending compulsory education does not entail a significant effect on belief accuracy, in both issues. Taken together, cross-sectional and causal estimates suggest that education is necessary, but not sufficient, to contrast inaccurate beliefs.

Testing, numerical modeling and design of perforated advanced high-strength steel channel section columns

This paper examines the influence of perforations on the buckling instability and load-bearing capacity of advanced high-strength steel channel section (C-section) columns. Experimental tests were first conducted on 19 column specimens made of complex phrase steel HC700CP980 under axial compression, followed by finite element (FE) analysis. Two section types, the flat web C-section and the web-stiffened C-section, were considered, with perforations categorised as web-only or both web and flanges. Material tests and initial imperfection measurements were conducted and reported. Using test results, finite element models were established and parameter analysis was carried out. Analysis of test results and finite element data revealed that perforations had a noticeable impact on the buckling deformation of flat web C-sections but had a minor effect on load-bearing capacity. In contrast, web-stiffened C-sections exhibited intensified deformation post-perforation, significantly reducing their axial stiffness and load-bearing capacity. The Direct Strength Method (DSM) was assessed based on combined test and FE data. It revealed that the DSM resulted in a high level of inaccuracy and scatter in the load-bearing capacity predictions of high-strength steel C-sections after perforation. To address this, a modified method incorporating a perforation strength reduction factor was proposed, offering straightforward and intuitive calculations with improved design accuracy and consistency.

Precise GNSS Time Synchronization With Experimental Validation in Vehicular Networks

Time synchronization utilizing the Global Navigation Satellite System (GNSS) is being increasingly investigated for vehicular networks. Due to GNSS signal blockages, the availability and accuracy of GNSS timing solutions in various road settings is a recognized challenge. With the recent improvement of Multi-GNSS technology and the increased capacity of consumer-grade receivers, the application of GNSS in vehicular environments has brightened up. This paper systematically analyzes the required time synchronization of vehicular networks and presents a GNSS-based time synchronization solution. It also experimentally demonstrates the availability and capabilities of GNSS time synchronization using commercial-grade GNSS receivers and off-the-shelf communication devices. Our experiments show that the timing accuracy of an individual vehicular node can be as good as ±2 microseconds, resulting in synchronization accuracy of sub-10 microseconds among nodes. A momentary complete outage of the GNSS time solution due to signal blockage on the road adds clock error, leading to synchronization inaccuracy of up to sub-20 microseconds. This level of inaccuracy still meets the desired requirement for most applications in vehicular communication.

Kinetic modelling of biomass fast devolatilization using Py-MS: Model-free and model-based approaches

Feasibility using quantitative data obtained from a micropyrolyzer coupled to an evolved gas analysis technique, mass spectrometry, for kinetics determination has been long demonstrated. This paper describes for the first time how to obtain intrinsic kinetics for fast devolatilization of biomass and its lignocellulosic fractions (e.i., holocellulose and lignins). The main challenge with online detection is assessing the time lag related to transport phenomena between the reactor and the detector. To do this, an experimental method was developed to derive the real-time biomass devolatilization profile; this provided 'corrected' datasets. Preliminary kinetic parameters were obtained from the differential isoconversional Friedman method combined with real-time sample temperature history. Not considering the effect of thermal lag and the delay in detecting pyrolysis products by the MS leads to a certain level of inaccuracies. Isoconversional activation energy (Eα) dependencies obtained in the absence of heat and mass transfer limitations for biomass and its components highly varied with conversion, confirming the multi-step nature of the fast pyrolysis process. After demonstrating the modeling limitations of a constant activation energy model (CAEM), both isoconversional functions were parametrized to propose a variable activation energy model (VAEM) and used as initial inputs for the distributed activation energy model.

Accuracy of Nursing Term Translation from Indonesian to English by Nursing Students

Translating the accuracy of source language into target language in specialized language requires high appropriation that retains of the original meaning. This study aims to discover the accuracy of nursing term translation from Indonesian to English by nursing students. This research is a mixed-method research with content analysis method to analyze the accuracy of translation. The accuracy of the translation results will be analyzed quantitatively and qualitatively. The research subject was the translation of Indonesian – English abstracts of nursing articles by nursing students of STIKES Surya Global Yogyakarta. The object of research was nursing special terms in the form of words and phrases. The data collection technique used was the documentation method used to find related data that has been determined. The results of this study showed that the accurate translation of nursing terms was 65.29% while the inaccurate translation was 34.71%. In addition, there were about 25% of accurate translations was plagiarism. It is considered plagiarism because the student's translation of the abstract was exactly as same as the original writer's English version of the abstract, not only the specific language but also the whole sentence. It can be concluded from this study that overall the translation of nursing students into the special language of nursing is accurate. There are only a few translations is still in low inaccuracy level.&#x0D; Keywords: Accuracy, Nursing term, Translation

Indoor Visible Light Positioning Based on Channel Estimation and Cramér–Rao Low Bound Analysis with Random Receiving Orientation of User Equipment

The accuracy of line-of-sight (LOS)-based indoor visible light positioning (VLP) depends directly on the accuracy of the received LOS power. In an actual indoor visible light communication (VLC) system, the total received power contains the LOS power and diffuse power, and the proportion of diffuse component varies significantly with the receiving orientation of the user equipment (UE). In the trilateration positioning process, this is bound to bring a very high level of inaccuracy for at least one or two of them when determining the distance between the positioned LED and UE. To solve this problem, we employed channel estimation and Parseval’s theorem to remove the diffuse component from the total received power. The simulation results show that the higher the channel estimation accuracy, the smaller the discrepancy between the estimated and actual LOS power, and the greater the localization accuracy. At the same channel estimation accuracy, the comparison results demonstrate that the localization performance of the proposed method is higher than LLS-1, in which the total received power is directly adopted to estimate the distance. The localization performance of LLS-2 deteriorates significantly compared to the proposed method. This result indicates that the receiving orientation cannot be neglected during the distance estimation process even though the estimated accuracy of LOS power is high. Deriving the Cramér–Rao low bound (CRLB) for LOS-based indoor VLP with receiving orientation, we compared the localization performance for the proposed method with LLS-1, LLS-2, and the CRLB at various signal-to-noise ratios (SNRs). The results show that the localization error of all the received positions in the room can reach the CRLB at approximately 25 dB. However, localization errors based on LLS-1 and LLS-2 cannot achieve the theoretical CRLB even at a high SNR.

Assessing the Feasibility of Replacing Subjective Questionnaire-Based Sleep Measurement with an Objective Approach Using a Smartwatch

In order to ensure sufficient recovery of the human body and brain, healthy sleep is indispensable. For this purpose, appropriate therapy should be initiated at an early stage in the case of sleep disorders. For some sleep disorders (e.g., insomnia), a sleep diary is essential for diagnosis and therapy monitoring. However, subjective measurement with a sleep diary has several disadvantages, requiring regular action from the user and leading to decreased comfort and potential data loss. To automate sleep monitoring and increase user comfort, one could consider replacing a sleep diary with an automatic measurement, such as a smartwatch, which would not disturb sleep. To obtain accurate results on the evaluation of the possibility of such a replacement, a field study was conducted with a total of 166 overnight recordings, followed by an analysis of the results. In this evaluation, objective sleep measurement with a Samsung Galaxy Watch 4 was compared to a subjective approach with a sleep diary, which is a standard method in sleep medicine. The focus was on comparing four relevant sleep characteristics: falling asleep time, waking up time, total sleep time (TST), and sleep efficiency (SE). After evaluating the results, it was concluded that a smartwatch could replace subjective measurement to determine falling asleep and waking up time, considering some level of inaccuracy. In the case of SE, substitution was also proved to be possible. However, some individual recordings showed a higher discrepancy in results between the two approaches. For its part, the evaluation of the TST measurement currently does not allow us to recommend substituting the measurement method for this sleep parameter. The appropriateness of replacing sleep diary measurement with a smartwatch depends on the acceptable levels of discrepancy. We propose four levels of similarity of results, defining ranges of absolute differences between objective and subjective measurements. By considering the values in the provided table and knowing the required accuracy, it is possible to determine the suitability of substitution in each individual case. The introduction of a “similarity level” parameter increases the adaptability and reusability of study findings in individual practical cases.

Non-Linear Analytical Model for the Study of Double-Layer Supercapacitors in Different Industrial Uses

It is generally considered that the representation of a double layer supercapacitor (DLSC) cannot be performed with the usual capacitance and resistance series connected, as it induces a relatively high level of inaccuracy in the results. In multiple previous studies, more advanced models have been developed with very different approaches: models with distributed parameter circuits, based on artificial neural networks (ANNs), fractional order, etc. A non-linear model, less complex than the previous ones and whose behavior adequately represents the DLSCs, is the one formed by a variable capacitance, dependent on its internal voltage. This paper presents a mathematical study to obtain analytical expressions of all the electrical variables of DLSCs, voltage, current, dissipated power and so on, by means of a previous model. This study is carried out considering that the DLSC is charged and discharged through a voltage source and also discharged through a resistor. In later sections, the operational conditions of the DLSC in numerous industrial applications are presented. Finally, a comparative analysis is made between the results produced by the conventional model, with constant capacitance, and the developed model. This analysis is finally followed by the conclusions.

Accumulating Errors in Tests of General Relativity with Gravitational Waves: Overlapping Signals and Inaccurate Waveforms

Observations of gravitational waves (GWs) from compact binary coalescences provide powerful tests of general relativity (GR), but systematic errors in data analysis could lead to incorrect scientific conclusions. This issue is especially serious in the third-generation GW detectors in which the signal-to-noise ratio (S/N) is high and the number of detections is large. In this work, we investigate the impacts of overlapping signals and inaccurate waveform models on tests of GR. We simulate mock catalogs for Einstein Telescope and Cosmic Explorer and perform parametric tests of GR using waveform models with different levels of inaccuracy. We find that the systematic error in non-GR parameter estimates could accumulate toward a false deviation from GR when combining results from multiple events, although a Bayesian model selection analysis may not favor a deviation. Waveform inaccuracies contribute most to the systematic errors, but multiple overlapping signals could magnify the effects of systematics owing to the incorrect removal of signals. We also point out that testing GR using selected “golden binaries” with high S/N is even more vulnerable to false deviations from GR. The problem of error accumulation is universal; we emphasize that it must be addressed to fully exploit the data from third-generation GW detectors and that further investigations, particularly in waveform accuracy, will be essential.

Knowledge, Attitude, and Practice Regarding Fibromyalgia Among Primary Care Physicians in Tabuk, Saudi Arabia.

Adequately informed family physicians have the greatest potential to correctly identify the diagnosis of fibromyalgia (FM) and develop an initial treatment plan. Therefore, it is substantial to determine the levels of weakness and inaccuracy among primary care physicians regarding FM diagnostic criteria and management strategies. This study aimed to assess the knowledge, attitude, and practices regarding FM among primary care physicians in Tabuk, Saudi Arabia. This cross-sectional study included family physicians who were board-certified or registered in the family medicine training program and working at the government family healthcare centers in Tabuk. A pre-designed, structured questionnaire was distributed either in written form or as an online survey. This study included 52 primary healthcare physicians. Twenty-two (42.3%) participants incorrectly recorded localized pain as a diagnostic symptom, and 45 (86.5%) incorrectly recorded nonsteroidal anti-inflammatory drugs (NSAIDs), prednisolone, and/or opioids as drugs that are used for treating FM. Only 59.6% were confident in recognizing the symptoms of FM, and 55.8% were confident in differentiating FM from other similar diseases. The primary healthcare physicians working in the government's primary healthcare centers in Tabuk City, Saudi Arabia, have low levels of knowledge about diagnostic criteria and treatment strategies for FM. These findings highlight the need for continuous professional development involving family physicians in the primary healthcare setting with suitable continuous medical education (CME) programs concerning FM.

KNOWLEDGE, ATTITUDE AND PRACTICE REGARDING FIBROMYALGIA AMONG PRIMARY CARE PHYSICIANS IN TABUK, SAUDI ARABIA

Background: Adequately informed family physicians have the greatest potential to correctly identify the diagnosis of fibromyalgia (FM) and develop an initial treatment plan. Therefore, it is substantial to determine the levels of weakness and inaccuracies of primary care physicians regarding FM diagnostic criteria and management strategies. Aim: This study aimed to assess the knowledge, attitude, and practices regarding FM among primary care physicians in Tabuk, Saudi Arabia. Methods:This cross-sectional study included family physicians who were board-certified or registered in the family medicine training program and working at the government family health care centers in Tabuk. A pre-designed, structured questionnaire was distributed either in a written form or as an online survey. Results: This study included 52 primary healthcare physicians. Twenty-two (42.3%) participants incorrectly recorded localized pain as a diagnostic symptom, and 45 (86.5%) incorrectly recorded nonsteroidal anti-inflammatory drugs, prednisolone, and/or opioids as drugs that are used for treating FM. Only 59.6% were confident recognizing symptoms of FM and 55.8% were confident differentiating FM from other similar diseases. Conclusions: The primary healthcare physicians working in the governments primary healthcare centers in Tabuk city, Saudi Arabia have low levels of knowledge about diagnostic criteria and treatment strategies of FM. These findings highlight the need for continuous professional development involving family physicians in the primary health care setting with suitable continuous medical education programs concerning FM.

Distributed fault-passage indicators versus central fault location: Comparison for reliability centred planning of resonant-earthed distribution systems

Fault location methods are crucial for reducing fault restoration time, and thus improving a network’s system average interruption duration index (SAIDI) and customer outage cost. Resonant-earthed systems pose problems for traditional fault location methods, leading to poor accuracy and a need for additional complexity. In this context, methods that detect fault direction (fault-passage indicators, FPI) at multiple points in the network may show advantages over a central distance-estimation method using fault locators (FL) of poor accuracy. This paper includes a comparative study of these two major fault location methods, comparing the reliability benefit from a varied number of FPIs or a central method. The optimal placement of the fault locating devices is found by formulating a mixed-integer linear programming (MILP) optimization approach that minimizes both outage and investment costs and assesses SAIDI. This approach has been tested on an example distribution system. However, to justify the universality of the algorithm, the RBTS reliability test system has also been analysed. The comparison of location methods and placement method of FPIs are useful for reliability centred planning of resonant-earthed distribution systems where fault location is to be used. Results show that a small number of FPIs that give accurate identification of direction may give more cost effective increase in reliability than a distance estimate by FL with typical levels of inaccuracy.

Dynamics of agricultural practices in corn (Zea mays L.) cultivation in the municipality of Jilotepec, Estado de Mexico.

Objective: Determine which agricultural practices are currently used by corn (Zea mays L.) growers in the municipality of Jilotepec, Estado de México.&#x0D; Design/methodology/approach: An individual survey composed of both open and close-ended questions was applied to 93 corn producers from the municipality of Jilotepec, Estado de México, in order to obtain information about the planting practices they carry out. From there, 10 producers were selected for on-site monitoring their plots. &#x0D; Results: Maize growers in Jilotepec, Estado de México, are conscious of the genetic and cultural richness of native maize. However, the agricultural practices they use for their production are centered on the conventional agricultural model using chemical compounds obtained by chemical synthesis and a part is focused on monoculture production.&#x0D; Study limitations/implications: The applied survey consisted of 13 questions, and the main limitation was the fact that it was not an extensive questionnaire because it is hard for people to devote a lot of time to this kind of polls; it is known that few questions generate more accurate information, while detailed polls have high levels of inaccuracy.&#x0D; Findings/Conclusions: The results of this study showed that most of the producers are dedicated to growing native corn with a single crop per year and do not use any agroecological practices for their production or only very limited ones; they are also convinced that it is important to preserve native corn as it is a wealth for the Mexican people.

Automatic Contour Refinement of Inaccurate Auto-Segmentation Using an Active Contour Model for MR-Guided Adaptive Radiotherapy

<h3>Purpose/Objective(s)</h3> One of the bottleneck problems of MR-guided adaptive radiotherapy (MRgART) is the impractically long time required to segment the patient's anatomy of the day. Deep learning auto-segmentation (DLAS) has a limited success for complex structures such as those in abdomen. We have previously proposed an active contour model (ACM) to automatically refine the inaccurate contours from DLAS. This study aims to improve the performance of the ACM method by further optimizing the method and testing it using large and diversified abdominal MRI datasets. <h3>Materials/Methods</h3> An improved ACM method that does not require any manual parameter adjustment was implemented. The ACM utilizes the probability maps generated from DLAS models to establish 2D parameter maps and to initialize contour evolution. The performance of the ACM method was tested on the inaccurate DLAS contours of abdominal organs from 91 MRI sets (76 sets of T2-HASTE sequence from a 3T MR-simulator and 15 sets of BTFE sequence from a 1.5T MR-Linac). Bowels were divided into multiple subregions with each including a bowel loop. Levels of contour inaccuracies were divided into two groups: (1) major error group with Dice similarity coefficient (DSC) <0.5 or mean distance to agreement (MDA) >8 mm, and (2) minor error group with remaining contours of 0.5≤ DSC<0.8 or 3 mm<MDA≤8 mm. The performance of the ACM was evaluated based on various metrics, e.g., DSC, MDA, and the added path length (APL, a metric that is correlated with contour editing time). Manually delineated contours were used as ground truth. <h3>Results</h3> As shown in the table below, the average DSC, MDA and APL values for all the contours were improved after the ACM correction. By applying this ACM, approximately half of the contours in major error group were improved to minor error group, and 12-40% of the contours became practically acceptable per TG-132 recommendation (DSC>0.8 and MDA<3 mm). The largest improvement was seen in the major error group of pancreases, where APL reduced by one third, indicating substantial reductions in the subsequent contour editing effort. The execution time of this method to correct one contour was around 1 second. <h3>Conclusion</h3> The ACM method was successfully implemented to automictically and quickly correct for inaccurate contours from MRI-based DL auto-segmentation for complex anatomy, e.g., bowels and pancreas, in abdomen. The ACM method may be used to reduce the manual contour editing workload and accelerate the segmentation process for MRgART.

Area and borders of Antarctic and permafrost—A review and synthesis

AbstractThe Antarctic continent is a crucial area for ultimate determination of permafrost extent on Earth, and its solution depends on the theoretical assumptions adopted. In fact, it ranges from 0.022 × 106 to 14 × 106 km2. This level of inaccuracy is unprecedented in the Earth sciences. The novelty of the present study consists in determining the extent of Antarctic permafrost not based exclusively on empirical studies but on universal criteria resulting from the definition of permafrost as the thermal state of the lithosphere, which was applied for the first time to this continent. The area covered by permafrost in Antarctica is ca. 13.9 million km2, that is its entire surface. This result was also made possible due to the first clear determination of the boundaries and area of the continent. The Antarctic area includes (a) rocky subsurface with (b) continental ice‐sheets and (c) shelf glaciers, which, due to their terrigenous origin and belonging to the lithosphere, belongs to the continent in the same way. Antarctica is covered by continuous permafrost, either in a frozen or in a cryotic state. This also significantly influences delimitation of the global extent of permafrost, which can therefore be defined much more accurately. The proposed ice reclassification and its transfer from the hydrosphere to the lithosphere will allow the uniform treatment of ice in the Earth sciences, both on Earth and on other celestial bodies.

How accurate are WorldPop-Global-Unconstrained gridded population data at the cell-level?: A simulation analysis in urban Namibia.

Disaggregated population counts are needed to calculate health, economic, and development indicators in Low- and Middle-Income Countries (LMICs), especially in settings of rapid urbanisation. Censuses are often outdated and inaccurate in LMIC settings, and rarely disaggregated at fine geographic scale. Modelled gridded population datasets derived from census data have become widely used by development researchers and practitioners; however, accuracy in these datasets are evaluated at the spatial scale of model input data which is generally courser than the neighbourhood or cell-level scale of many applications. We simulate a realistic synthetic 2016 population in Khomas, Namibia, a majority urban region, and introduce several realistic levels of outdatedness (over 15 years) and inaccuracy in slum, non-slum, and rural areas. We aggregate the synthetic populations by census and administrative boundaries (to mimic census data), resulting in 32 gridded population datasets that are typical of LMIC settings using the WorldPop-Global-Unconstrained gridded population approach. We evaluate the cell-level accuracy of these gridded population datasets using the original synthetic population as a reference. In our simulation, we found large cell-level errors, particularly in slum cells. These were driven by the averaging of population densities in large areal units before model training. Age, accuracy, and aggregation of the input data also played a role in these errors. We suggest incorporating finer-scale training data into gridded population models generally, and WorldPop-Global-Unconstrained in particular (e.g., from routine household surveys or slum community population counts), and use of new building footprint datasets as a covariate to improve cell-level accuracy (as done in some new WorldPop-Global-Constrained datasets). It is important to measure accuracy of gridded population datasets at spatial scales more consistent with how the data are being applied, especially if they are to be used for monitoring key development indicators at neighbourhood scales within cities.