Indirect Estimation Methods Research Articles

Socio-economic differentials of under-five mortality in Botswana: an application of the indirect estimation method

Abstract Background Socio-economic differentials in infant and under-five mortality exist in all countries worldwide, but the extent of differentials varies across countries. This study aimed to examine the socio-economic differentials of under-five mortality in Botswana within the framework of equality and equity. Methods and findings The analysis for this paper was based on the data from 2001 and 2011 Botswana Population and Housing Censuses and the 2017 Botswana Demographic Survey. One census method was used to indirectly estimate under-five mortality for different socio-economic groups using Princeton west model life tables. Results from this study revealed that socio-economic disparities in under-five mortality disfavouring the worse-off exist in all the selected socio-economic variables. The variations of socio-economic groups by mother’s place of residence and employment status have been narrowing over time, whereas the differences of socio-economic groups by mother’s level of education and marital status have been widening over time. Conclusions The findings of this study show that policies and interventions targeted at reducing inequalities should reach all socioeconomic groups across the country. Differences of each society and localities should be considered while designing and implementing policies and interventions.

Impact of experimental setup parameters on the measurement of articular cartilage optical properties in the visible and short near-infrared spectral bands.

There is increasing research on the potential application of diffuse optical spectroscopy and hyperspectral imaging for characterizing the health of the connective tissues, such as articular cartilage, during joint surgery. These optical techniques facilitate the rapid and objective diagnostic assessment of the tissue, thus providing unprecedented information toward optimal treatment strategy. Adaption of optical techniques for diagnostic assessment of musculoskeletal disorders, including osteoarthritis, requires precise determination of the optical properties of connective tissues such as articular cartilage. As every indirect method of tissue optical properties estimation consists of a measurement step followed by a computational analysis step, there are parameters associated with these steps that could influence the estimated values of the optical properties. In this study, we report the absorption and reduced scattering coefficients of articular cartilage in the spectral band of 400-1400 nm. We assess the impact of the experimental setup parameters, including surrounding medium, sample volume, and scattering anisotropy factor on the reported optical properties. Our results suggest that the absorption coefficient of articular cartilage is sensitive to the variation in the surrounding medium, whereas its reduced scattering coefficient is invariant to the experimental setup parameters.

Pattern and trends of the total and age-specific fertility rates during 1990–2018 in Pakistan

BackgroundPakistan has an inadequate vital event registration system, leading to fewer than half of all births being registered, and this issue is further exacerbated by systematic recall errors and omission of births. This study aims to evaluate direct and indirect methods of fertility estimation to analyze the trends and patterns of fertility rates in Pakistan from 1990 to 2018.Design/methodology/approachIndirect methods are utilized in this study to evaluate the direction and extent of changes in total and age-specific fertility rates, and these findings are compared to direct estimates. The study draws data on livebirths from four waves of the Pakistan Demographic and Health Survey that took place between 1990 and 2018. To ensure the quality of data, graphical methods and Whipple and Myers indices are employed. Additionally, the Brass Relational Gompertz model was used to analyze the data.ResultsThe Relational Gompertz model revealed that total fertility rates (TFRs) were higher than direct estimates by 0.4 children and age-specific fertility rates (ASFR) were higher for all age groups except the oldest. The difference was more significant among younger women aged 15–24, and less so for age groups 29 and above. The gap in estimated fertility between direct and indirect methods decreased with age.ConclusionThe indirect method is an invaluable tool in situations where direct measurement of fertility rates is challenging or impossible. By utilizing this method, policymakers can gain important insights into the fertility patterns and trends of a population, which is crucial for making informed decisions on fertility planning.

Indirect force estimation method under spectrally varying and amplitude-sensitive conditions by estimating the effective fluid path parameter

Indirect methods to estimate the force transmitted from the source to the receiver have been investigated using various approaches to increase accuracy and overcome discrepancies, especially when the measurements are conducted in situ. To implement the indirect force estimation techniques in situ, developing an accurate measurement method and establishing reasonable system models always matter when the force estimations involve nonlinear internal forces such as the upper chamber pressures of the hydraulic mount system. Based on prior research conducted on force estimation in a nonlinear hydraulic mount, a simplified reverse-path spectral method is proposed in this study for estimating the force transmitted from the driving point to the ground by focusing on one effective fluid path parameter. To achieve the purpose of this study, two interfacial force datasets from the non-resonant test were first captured along with spectrally varying and amplitude-sensitive conditions. Second, two different path forces were determined from the rubber and hydraulic paths, and the effective fluid path parameter (EFP) was estimated from the hydraulic path force. The employment of the EFP contributes to estimating the effective internal properties, which show better correlations with the measurements than the estimated results from prior studies. Thus, the current work, performed by focusing on the EFP, successfully suggests a simplified yet efficient way to develop an indirect force estimation method in a nonlinear hydraulic mount as a dynamic load sensing system.

Density estimation of an ultrahigh-speed rarefied flow field based on force analysis of a pendulum sphere

The similarity criterion for high speed or high enthalpy rarefied reaction flows is the binary scaling law, one of which is the product of the incoming flow density and the characteristic scale of the test model in a rarefied wind tunnel should be equal to that under the flight condition. This is to ensure that the ratio between the characteristic distance of the relaxation process and the characteristic length of the body is equal. However, in a rarefied wind tunnel, it is difficult to directly measure the flow density below 10−5 kg/m3 using common methods due to the relatively high rarefied degree, an indirect density estimation method based on force analysis of a pendulum sphere was proposed in this study. The oscillation trajectory of the pendulum sphere under ultrahigh-speed rarefied flow conditions was recorded and the corresponding aerodynamic drag force acted on the sphere along the trajectory was analyzed, based on which the density distribution of the flow was then estimated combined with DSMC simulations. The obtained results show that in the present study, the flow is in under-expanded condition and the measured density sharply decreased from 10−6 kg/m3 to 10−7 kg/m3 at 140–170 mm from the nozzle outlet.

A practical and robust method for beam blocker-based cone beam CT scatter correction

Objective. In the traditional beam-blocker based cone beam CT (CBCT) scatter correction, the scatter measured in the region shaded by lead strips was multiplied by a correction factor to directly represent the scatter in the unblocked region. The correction factor optimization is a tedious process and lacks an objective stop criterion. To skip the optimization process, an indirect scatter estimation method was developed and validated in phantom imaging. Approach. A beam-blocker made of lead strips was mounted between the x-ray source and object for scatter estimation. The primary signal between lead strips in the blocked region was first calculated by subtracting the measured scatter, and then used to calculate the scatter signal in the unblocked region corresponding to the same attenuation path. The calculated scatter signal was smoothed via local filtration and used to correct the measured projection in the unblocked region. Finally, the CBCT was reconstructed via Feldkamp–Davis–Kress algorithm. A Catphan and a head phantom were used to verify the performance of the proposed method in both full- and half-blocker scenarios, and with and without a bow-tie filter. Main Results. For scans without the bow-tie filter, the CT number error was reduced to 3.97 2.27 and 5.51 3.90 HU in the full- and half-blocker scenarios, respectively, for the Catphan, and to 4.01 2.18 and 7.97 ± 4.05 HU for the head phantom. When the bow-tie filter was applied, the CT number error was reduced to 2.29 1.42 and 6.72 0.77 HU in the full- and half-blocker scenarios, respectively, for the Catphan, and 2.35 1.25 and 4.96 ± 1.89 HU for the head phantom. Significance. The proposed method effectively avoids the influence of the inserted beam blocker itself on the scatter intensity estimation, and proves a more practical and robust way for the beam-blocker based scatter correction in CBCT scanning.

ASSESSMENT OF THE PARAMETERS OF THE FUTURE DEMOGRAPHIC SITUATION IN KAZAKHSTAN

In the article, forecasts are based on the concept of demographic transition and the theory of a stable population, model mortality tables. Methods of indirect estimation of demographic indicators are used for countries with incomplete information about the population. The forecasts are based on the concept of demographic transition and the theory of a stable population, model mortality tables. Methods of indirect estimation of demographic indicators are used for countries with incomplete information about the population.

REVISIÓN SISTEMATIZADA DEL MÉTODO COSTO DE VIAJE: UNA APROXIMACIÓN A LA VALORACIÓN ECONÓMICA DE ÁREAS NATURALES PROTEGIDAS

<p><strong>Background:</strong> In protected natural areas (PNA), as units for the management and conservation of natural ecosystems, the challenge of economically valuing their environmental services sometimes makes it difficult to improve the design of their conservation plans and prevents a correct estimation of economic and social impacts on the well-being of present and future generations. Therefore, indirect estimation methods of the recreational value are used. <strong>Objective:</strong> Systematically analyze the advances in the estimation of the recreational value of the PNA, through the travel cost method (TCM). <strong>Methodology: </strong>A systematic literature review was carried out, based on SALSA (Search, AppraisaL, Synthesis, Analysis) and the PRISMA protocol (Preferred Reporting Items for Systematic reviews and Meta-Analyses), in the following databases: Scopus, Science Direct, JSTOR, Springer Link, Dialnet, Google Scholar. Inclusion and exclusion criteria were used for studies carried out in PNA at a national and international level, in the period from 2010 to 2020. <strong>Main findings.</strong> Regarding the different approaches of the travel cost method, the individual approach provides more realistic estimates and has greater statistical support than the zonal approach; since it obtains the data directly from tourists through surveys, which allows estimating the real expenses they made during their trip. <strong>Implications:</strong> Derived from the complexity of estimating the value of an intangible, such as these areas of environmental services. The economic valuation exercise results in the estimation of the price of the service from the consumer's demand and not from its offer. In this sense, the TCM seeks to estimate the use value of the PNA, and not their market value as such. Hence, such assessment is a support tool for the managers of these sites, in order to: estimate adequate access fees; evaluate investments in the valued area; as well as expose specific approaches and techniques for data processing. <strong>Conclusions:</strong> The variables that influence the recreational value are: age, income level, distance traveled from the tourist's place of residence to the PNA, transportation costs, lodging, food costs, visits to other sites, perception of environmental quality, and willingness to pay (WTP) for the service. It is recommended to delve into intangible valuation techniques, so that society becomes aware of the benefit that PNA represent for a nation, and in this way public and private investments in this area are promoted; since in addition to improving the protection of biodiversity, it contributes to regional development.</p>

Poisson-Lognormal model with measurement error in covariate for small area estimation of count data

Small Area Estimation (SAE) is a statistical technique to estimate parameters of subpopulation containing small-size of samples. SAE is an indirect estimation method by utilizing the strength of the neighbor area and data sources outside the area so that the sample becomes more effective and reduces the variance of parameter estimators. This paper deals with non-symmetrical count data in SAE which can be modelled based on Poisson-Lognormal distribution using hierarchical Bayesian (HB) approach and information on covariate contains measurement error. We develop the Poisson-Lognormal model for predicting small area counts with structural measurement error in the area-specific covariate. To get the HB Bayes estimator for Poisson-Lognormal model with measurement error in its covariates, the Metropolis-Hastings (MH) algorithm from the Markov Chain Monte Carlo (MCMC) technique is used. The HB estimator performance is studied through simulation and implementation of real data to predict the illiteracy rate at the sub-district level in Kepulauan Riau Province Indonesia based on The National Socio-Economic Survey (Susenas) data in March 2020.

Prevalence of adult smokers in Brazilian capitals according to socioeconomic deprivation.

To estimate the prevalence of adult smokers in the 26 capitals and the Federal District according to the Brazilian Deprivation Index (Índice Brasileiro de Privação - IBP). Dataset on smoking were obtained from the Surveillance of Risk and Protective Factors for Noncommunicable Diseases by Survey (Vigitel) system for the 26 capitals and the Federal District, in the period from 2010 to 2013. The IBP classifies the census sectors according to indicators such as: income less than ½ minimum wage, illiterate population and without sanitary sewage. In the North and Northeast regions, the census sectors were grouped into four categories (low, medium, high and very high deprivation) and in the South, Southeast and Midwest regions into three (low, medium and high deprivation). Prevalence estimates of adult smokers were obtained using the indirect estimation method in small areas. To calculate the prevalence ratios, Poisson models are used. The positive association between prevalence and deprivation of census sector categories was found in 16 (59.3%) of the 27 cities. In nine (33.3%) cities, the sectors with the greatest deprivation had a higher prevalence of smokers when compared to those with the least deprivation, and in two (7.4%) there were no differences. In Aracaju, Belém, Fortaleza, João Pessoa, Macapá and Salvador, the prevalence of adult smokers was three times higher in the group of sectors with greater deprivation compared to those with less deprivation. Sectors with greater social deprivation had a higher prevalence of smoking, compared with less deprivation, pointing to social inequalities.

A Bayesian regression analysis of in situ stress using overcoring data

Characterising the state of in situ stress at a target depth is crucial for all underground engineering projects. Consequently, on critical projects such as nuclear waste repositories extensive campaigns are implemented with the goal of estimating the in situ stress state. These campaigns often comprise both direct measurement and indirect estimation methods, but the data obtained across a project volume may exhibit significant variability. This poses significant challenges in both quantifying the variability and uncertainty of in situ stress, and determining the stress state to be used for design purposes.It is often assumed that the state of in situ stress increases linearly with depth, and thus linear regression of principal stress magnitude against depth are often found in the literature. As such methods not honouring the tensorial nature of stress are, strictly, incorrect. To show how this limitation may be overcome, here we present a Bayesian regression analysis of in situ stress with depth that uses the Cartesian stress tensor. The analysis is performed using over 100 overcoring data obtained at the SKB Forsmark site in Sweden.A comparison between the customary and Bayesian approaches is presented, which shows the superiority of the tensorial technique.

An On-Line Calibration Method for TSEP-Based Junction Temperature Estimation

Temperature sensitive electrical parameters (TSEP) provide an indirect and noninvasive method for on-line junction temperature estimation of power semiconductor devices. It is known that the fundamental of TSEP-based methods is to calibrate the relationship between TSEP and junction temperature in advance. However, the calibration methods in the literature need to open the module, require pretesting, or record the operating data of a converter in the entire power rating range, which are inconvenient in field applications. This article proposes an on-line and noninvasive calibration method by measuring the data at three operating states that are already existed in the regular converter operation. It is achieved by measuring the accessible heatsink/case temperature and TSEP during converter regular operation. The concept, implementation, and error analysis of the proposed method are presented in this article. Experimental verification is given to prove the effectiveness, accuracy, and convenience of the proposed method.

An Indirect State-of-Health Estimation Method Based on Improved Genetic and Back Propagation for Online Lithium-Ion Battery Used in Electric Vehicles

Lithium-ion battery state of health (SOH) estimation technology is an important part of the design of a battery monitoring system (BMS) for electric vehicles. People often use battery capacity and internal resistance as SOH estimation indicators. However, due to actual working conditions, it is difficult for electric vehicles to achieve complete charge and discharge, so the battery capacity and internal resistance cannot be monitored online. In view of the above questions, this article proposes an indirect SOH estimation method for online EV lithium-ion batteries based on arctangent function adaptive genetic algorithm combination with back propagation neural network (ATAGA-BP). Firstly, constant current drop time (CCDT), constant current drop capacity (CCDC) and maximum constant current drop rate (MCCDR) in constant voltage charging stage are used as health indicator (HI) to evaluate battery SOH in order to indirectly quantify the degradation process of lithium-ion batteries. Error point optimization and correlation verification are also carried out. Secondly, an ATAGA-BP algorithm is proposed to establish the relationship between HI and available battery capacity, and SOH estimate is made for lithium-ion batteries according to the proposed algorithm. Finally, simulation results with NASA data show the correlation between the proposed HI and lithium-ion battery capacity is above 85%, the error of SOH estimation method proposed is 3.7%, and the iteration efficiency is increased by 17.8%.

High-accurate cutting forces estimation by machine learning with voice coil motor-driven fast tool servo for micro/nano cutting

In a machining process, cutting force is one of the most important machining parameters which can directly reflect the state of tool and quality of the machined workpiece. The cutting force in micro/nano cutting is required to be measured with a high accuracy of a few millinewtons. However, traditional cutting force indirect estimation methods are difficult to meet the high-accurate measurement requirement. In this paper, a reliable and high-accurate cutting force estimating method based on machine learning for a fast tool servo driven by Lorentz force without using additional sensors is proposed. A concept of virtual forces, which could enable obtaining sufficient type of forces than that by actual cutting, is developed to increase the data training accuracy. In addition, an effective data filtering method combining the fast Fourier transform and the inverse fast Fourier transform is adopted to further improve the estimation accuracy. Cutting force estimated by the proposed method is compared with that estimated by traditional disturbance observer and Kalman filter, which demonstrates a much better estimation accuracy. The experiment results show that the estimated cutting force is in good consistent with the best commercial dynamometer. Even the details of small cutting force fluctuation on the order of 50 mN can be clearly identified. The experimental results demonstrated that the cutting force estimation method for micro/nano machining process could have a high measurement resolution of 10 mN and relatively measurement error as small as 0.4%.

Numerical Investigation of the Impact of Onshore Fish Farming on the Western Coast of Algeria

A methodology for aquaculture site selection is presented using a combined hydrodynamic/nutritional model to predict fish farm wastes and dispersion, using the indirect fish waste estimation method, and the numerical model MIKE 21. This method can be used as a basis for assessment of the environmental impact of fish farms. The models were applied for a virtual inland fish farm to harvest 450 tons of sea bass in the west coast of Algeria. The results show that the fish farm effluents quantities and dispersion depends on the production cycle and size, the hydrodynamic parameters, as well as the food quantity and composition. The suspended waste, nitrogen and phosphorus are respectively the main contributors to the fish farm pollution. The current speed varies from 0.005 to 0.045 m/s, while the nitrogen and phosphorus concentrations reached 2.1 mg/L, and 0.03 mg/L respectively. This study allows the Algerian authorities to decide upon delivering fish farming permissions in the studied area, by identifying the suitability of the area for aquaculture, and predicting potential fish farm pollution. The use of numerical models in aquaculture could help reducing installation, water treatment costs and the environmental impact of fish farms by contributing to the sustainability of the activity.

RF24 | PSUN116 Once-weekly semaglutide delays a late phase gastric emptying of solid meal measured by repeated scintigraphic imaging in obese women with PCOS

Abstract Background GLP-1 agonism have the potential to affect gastric emptying (GE), yet the reports for subcutaneous semaglutide, currently the most effective GLP-1 RA approved for weight management, remain inconclusive. It has been demonstrated that once-weekly semaglutide either had no effect on GE or it delayed GE only within the first hour, without late phase retention. Notably, those conclusions were made by an indirect method of estimation of GE through ingestion, absorption and determination of plasma level of paracetamol. Furthermore, in most previous studies with once weekly semaglutide, GE has been evaluated as a part of the composite outcome. The indirect method with paracetamol was shown to be appropriate for evaluation of kinetics of liquid meals, whereas it might lead to inaccurate estimation of late phase GE. Scintigraphic evaluation is considered as a reference method for the purpose. Aim This is the first study that evaluates the effect of once weekly subcutaneous semaglutide on late phase GE of a solid meal by scintigraphy in obese women with PCOS without other comorbidities as a primary outcome. Materials and Methods A single-blind, placebo-controlled trial was conducted in 20 women with PCOS and obesity, without diabetes and other comorbidities, randomized to once weekly subcutaneous semaglutide 1 .0 mg (S) or placebo (P) for 8 weeks. Gastric emptying was assessed by scintigraphy after ingestion of 99mTC colloid in pancake labelled with radiopharmaceutical that maintained a stable binding within gastric environment by scintigraphy using sequential static imaging and dynamic acquisition. Estimation of GE was obtained by repeated imaging of remaining 99mTC activity (RA) at fixed time intervals over 4 hours and the half time (T1/2) of gastric emptying had been calculated. Additionally, we evaluated anthropometric, metabolic, hormonal and appetite parameters. Results At 30 min after ingestion significant difference in RA was observed between semaglutide group and placebo (92.5% in S vs. 89% in P (p=0,05)) and persisted throughout the observation period up to 4 hour (37% in S vs. 0% in P (p=0,002)). T1/2 was significantly longer in S as compared to P (171 min vs 118 min, respectively (p<0.001)). In addition, semaglutide led to significant decrease in weight, waist and neck circumference, HbA1c and androgen levels. Subjective ratings of appetite suppression correlated with T1/2. Conclusion Once weekly semaglutide 1.0 mg resulted in a significant late-phase retention of solid meal measured by repeated scintigraphic imaging. This effect correlated with appetite suppression and likely contributed to weight loss. Presentation: Sunday, June 12, 2022 12:30 p.m. - 2:30 p.m., Sunday, June 12, 2022 1:18 p.m. - 1:23 p.m.

RIbench: A Proposed Benchmark for the Standardized Evaluation of Indirect Methods for Reference Interval Estimation.

Indirect methods leverage real-world data for the estimation of reference intervals. These constitute an active field of research, and several methods have been developed recently. So far, no standardized tool for evaluation and comparison of indirect methods exists. We provide RIbench, a benchmarking suite for quantitative evaluation of any existing or novel indirect method. The benchmark contains simulated test sets for 10 biomarkers mimicking routine measurements of a mixed distribution of non-pathological (reference) values and pathological values. The non-pathological distributions represent 4 common distribution types: normal, skewed, heavily skewed, and skewed-and-shifted. To identify strengths and weaknesses of indirect methods, test sets have varying sample sizes and pathological distributions differ in location, extent of overlap, and fraction. For performance evaluation, we use an overall benchmark score and sub-scores derived from absolute z-score deviations between estimated and true reference limits. We illustrate the application of RIbench by evaluating and comparing the Hoffmann method and 4 modern indirect methods -TML (Truncated-Maximum-Likelihood), kosmic, TMC (Truncated-Minimum-Chi-Square), and refineR- against one another and against a nonparametric direct method (n = 120). For the modern indirect methods, pathological fraction and sample size had a strong influence on the results: With a pathological fraction up to 20% and a minimum sample size of 5000, most methods achieved results comparable or superior to the direct method. We present RIbench, an open-source R-package, for the systematic evaluation of existing and novel indirect methods. RIbench can serve as a tool for enhancement of indirect methods, improving the estimation of reference intervals.

Research on indirect measurement and estimation method of shearer drum cutting load

For the difficult problem that the shearer drum load is difficult to be detected and perceived directly, a shearer drum load indirect estimation measurement method and technique is proposed and invented. Based on the structural characteristics of the rocker arm, the basic rod system skeleton of the rocker arm is extracted. Based on the transfer route of the drum load on the rocker arm, the feasibility of using the rocker arm pin shaft load for drum load prediction is analyzed, and the correlation mechanics equation of load from the drum to the rocker arm pin shaft is constructed. To address the statically indeterminate problem in the equation, the Lagrange multiplier is introduced to construct the energy function of the rocker rod system skeleton. Based on the principle of minimum complementary energy and solving the extreme value of energy function, the statically indeterminate equation is transformed into the statically determinate equation, and a rough prediction model of drum load based on the force of the rocker arm hinged ear pin shaft is derived, and the maximum relative error of the model is 25.15 %. To address the low prediction accuracy of the model due to the dynamic characteristics of the drum rocker arm, the drum load is derived from the rocker arm hinged ear pin shaft load and the rough prediction model as input, and the experimentally measured drum load as output. The bp neural network error correction model is constructed, and the accurate estimation and perception of the drum load are realized by the prediction model and the bp neural network correction model. Finally, the accuracy of the prediction algorithm is verified by experiments. The results show that after correction by bp neural network, the average error of the drum three directional force is 0.14 × 104N ∼ 0.55 × 104N, the mean square error is 0.18 × 104N ∼ 0.65 × 104N, and the relative error is 3.99 %∼10.12 %. The average error of the drum three directional moment is 0.31 × 104N·m ∼ 0.40 × 104N·m, the mean square error is 0.16 × 104N·m ∼ 0.50 × 104N·m, and the relative error is 2.04 %∼11.44 %. The accuracy of drum load prediction is higher than 11.44 % in all cases. The research results can provide theoretical and technical support for intelligent shearer design, development, and healthy operation and maintenance.

Indirect Spectrophotometric Method for Estimation of Irbesartan in Pure and in Pharmaceutical Dosage Form Using Oxidation and Reduction Reaction

Indirect Spectrophotometric Method for Estimation of Irbesartan in Pure and in Pharmaceutical Dosage Form Using Oxidation and Reduction Reaction

Progress in research of population size estimation by network scale-up method

Network scale-up method is an indirect population size estimation method based on social network theory. It is widely used in estimating the hidden population size because it does not need to contact the target population. In order to provide reference for the further application of this method, this paper summarizes the traditional network scale-up method, the progress of this method and its combination with new survey techniques.