Alternative Test Procedure Research Articles

The HDI + ROPE decision rule is logically incoherent but we can fix it.

The Bayesian highest-density interval plus region of practical equivalence (HDI + ROPE) decision rule is an increasingly common approach to testing null parameter values. The decision procedure involves a comparison between a posterior highest-density interval (HDI) and a prespecified region of practical equivalence. One then accepts or rejects the null parameter value depending on the overlap (or lack thereof) between these intervals. Here, we demonstrate, both theoretically and through examples, that this procedure is logically incoherent. Because the HDI is not transformation invariant, the ultimate inferential decision depends on statistically arbitrary and scientifically irrelevant properties of the statistical model. The incoherence arises from a common confusion between probability density and probability proper. The HDI + ROPE procedure relies on characterizing posterior densities as opposed to being based directly on probability. We conclude with recommendations for alternative Bayesian testing procedures that do not exhibit this pathology and provide a "quick fix" in the form of quantile intervals. This article is the work of the authors and is reformatted from the original, which was published under a CC-BY Attribution 4.0 International license and is available at https://psyarxiv.com/5p2qt/. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Generalized kernel two-sample tests

Summary Kernel two-sample tests have been widely used for multivariate data to test equality of distributions. However, existing tests based on mapping distributions into a reproducing kernel Hilbert space mainly target specific alternatives and do not work well for some scenarios when the dimension of the data is moderate to high due to the curse of dimensionality. We propose a new test statistic that makes use of a common pattern under moderate and high dimensions and achieves substantial power improvements over existing kernel two-sample tests for a wide range of alternatives. We also propose alternative testing procedures that maintain high power with low computational cost, offering easy off-the-shelf tools for large datasets. The new approaches are compared to other state-of-the-art tests under various settings and show good performance. We showcase the new approaches through two applications: the comparison of musks and nonmusks using the shape of molecules, and the comparison of taxi trips starting from John F. Kennedy airport in consecutive months. All proposed methods are implemented in an R package kerTests.

Operating in the “Danger Zone”: Contactor Dropout Versus Fuse Clearing Time

The most common and economical arrangement for medium-voltage motor controllers is to self-supply from the primary motor circuit. In this arrangement, a short circuit collapses the line voltage, causing the contactor to “drop out.” For low-level faults that nevertheless exceed the interrupting rating of the contactor, it is common for the dropout time to be faster than the clearing time for the fuse. Although this fault current is extremely unlikely to occur, no provisions exist in current standards to permit the application of contactors in this manner. To prevent the contactor from attempting to clear a fault current above its rating, less than optimal fuses must be selected, and complex and expensive supplemental power supply circuits are added to ensure that the holding coil remains energized until the fuse clears the fault. The tradeoffs of the short circuit clearing time versus the rated current to achieve a takeover point below the interrupting rating of a contactor are illustrated. In response to a customer request, an alternative test procedure to demonstrate capability where contactor dropout precedes fuse clearing was performed; actual results of such tests are included.

Time-varying Z-score measures for bank insolvency risk: Best practice

We evaluate several alternative approaches to constructing time-varying Z-scores as bank insolvency risk measures. Focusing on US and European banks during the financial crisis of 2007–2008, we compare the different measures considered using a range of alternative testing procedures. For both US and European data, Z-scores computed with the exponentially weighted moments method are shown to be preferable to those computed with the more commonly used moving moments approach. Generally, or if only simple moving moments are used, Z-scores computed with current values of the capital-asset ratio are recommended.

Effect of compression precracking on the near threshold fatigue crack propagation in an AISI 316L stainless steel

This work addresses an alternative test procedure based on fatigue precracking under compression to mitigate the potential effects of crack closure on near-threshold fatigue data and, thus, to obtain more consistent and reliable ΔKth-values. The method relies on performing a compression precracking, in which both maximum and minimum loads are compressive, thereby resulting in a tensile residual stress field at the crack tip. Fatigue crack growth (FCG) tests conducted on an AISI 316L stainless steel provide the experimental data upon which the near-threshold fatigue crack growth rate data for different test techniques can be determined. The experimental program includes FCG tests conducted on conventional C(T) specimens with crack size to specimen width ratio a/W=0.2, single edge notched SE(B) specimens under three-point bending with a/W=0.2 and two different span sizes, S, characterized by S/W=4 and 8. Overall, the present investigation shows that combining the compression precracking technique with the utilization of non-standard bend specimens having increased span improves evaluation of the near-threshold fatigue crack growth rate data for the tested AISI 316L steel, thereby providing more accurate ΔKth-values.

Lung function test in advanced age

Advanced age is not an obstacle to carring out alung function test. In most cases alung function test is necessary due to the fact that about 20% of older persons are affected by an obstructive respiratory disorder. Standard values for the lung function test are available up to advanced ages. The experience of the examiner and a calm environment for the lung function test have an impact on the quality of the measurement results. Severe cognitive impairments and severe immobility make the performance of alung function test impossible. Simple geriatric assessments can help to reliably identify these patients. Alternative lung function test procedures have to be validated in order to adequately diagnose this vulnerable subgroup of patients at risk.

Comparison of wrought and additively manufactured IN718 concerning crack growth threshold and fatigue crack growth behaviour

Rotary components in turbine machinery such as gas turbine blades and discs or turbocharger wheels need to be designed so that high cycle fatigue (HCF) loads are well below the fatigue endurance limit to ensure safe operation. This requires an accurate measurement of the fatigue endurance limit and the related intrinsic fatigue crack growth (FCG) threshold. Furthermore, knowing the FCG threshold is crucial in order to assess the criticality of initial defects (e.g. cavities, carbide nests, etc.). In this study, the influence of the manufacturing route on the FCG threshold and the FCG behaviour at 650 °C in air of the nickel based superalloy IN718 is investigated. For this, a per Laser Powder Bed Fusion (LPBF) process manufactured version is compared to a conventionally wrought IN718 material state, both in the short and long crack regime. To measure crack growth increments of about 1 μm, an alternative pre-cracking and threshold test procedure is proposed for high temperature testing. To assess the behaviour of both material states in the short crack growth regime, cyclic R-curves have been generated taking the influence of two different R ratios into account. A further comparison of the FCG behaviour of the LPBF and the wrought material state is made on the basis of da/dN-ΔKI plots, with a focus on the Paris regime created from both classical FCG tests as well as continued threshold tests. The results observed are discussed in relation to the initial characterization of the two material states, which includes tensile tests at room temperature and at 650 °C as well as microstructural investigations.

Ring Hoop Tension Test for yield strength estimation: Numerical analysis for a novel correlation method and applicability for mechanical testing of tubes and pipes

The tubes and pipes manufacturing industry characterizes the mechanical properties of their products with a wide selection of standards, but most of them are qualitative testing methodologies. To estimate the mechanical properties from a quantitative point of view there are limited options in standards. In that sense, the standard tensile test is the preferred alternative by the manufacturers, but this option limits the mechanical estimation for the longitudinal direction of the tube–pipe product. Particular efforts have been made to design an alternative mechanical testing procedure to characterize the mechanical properties in the hoop direction of pipes and tubes. The Ring Hoop Tension Test (RHTT) was designed to fill this gap, but it shows limitations related to the required tooling and the influence of the frictional contact between the tooling and the ring specimen. In the nuclear industry, the Small Ring Test (SRT), a miniature test derivated from the RHTT, has been investigated in recent years. In this investigation, a novel RHTT was designed to overcome the limitations of SRT and RHTT, and a new procedure was implemented to estimate the yield strength of tubes and pipes. Numerical FEM simulations were performed to reach an optimum estimation method for the yield strength with the specific geometry of the SRT and a wide selection of pipe geometries with the RHTT. A set of hypothetical materials were designed to perform these analyses, taking into account the influence of Young’s modulus, proportional limit, hardening coefficient (based on the Ramberg–Osgood law), and presence of Lüders bands straining. To verify the results obtained from this numerical FEM analysis, experimental tests (standard tensile tests and RHTTs) and metallographic analysis were performed on aluminum Al 6063 T6 and copper C12200 R360 tubes, showing the capability of this optimized RHTT to estimate the yield strength in the hoop direction for anisotropic tubes and pipes.

Estimating the Thermal Conductivity of Asphalt Binders

Abstract Nowadays, there is a common worldwide interest in environmental issues and pavements. How to save energy and mitigate the urban heat island (UHI) effect are topics that are drawing the attention of different researches and industrial organizations. In road infrastructure, one of the important properties addressing environmental and UHI aspects of pavements is the determination of the thermal conductivity. Asphalt concrete represents the third most widely used resource in the world, with asphalt-paved roads being its principal usage. One of the most important components of asphalt concrete is bitumen. Bitumen is a viscoelastic material susceptible to temperature changes. The determination of the bitumen’s thermal conductivity becomes very important in understanding and improving its thermal performance. There are very few test methods and equipment to measure thermal conductivity of bitumen (asphalt binders). Some are expensive and require special equipment and instrumentation. This study developed and validated a simplified testing technique to measure thermal conductivity of asphalt binders. This test is a steady state–based method to estimate the thermal conductivity of asphalt binders using cylindrical samples poured into a silicon mold. The method was validated using material of known thermal conductivity. A total of 18 samples of different binder grades were tested, and the test results were repeatable and within known thermal conductivity values. Sensitivity analysis and accuracy of the proposed method were validated modifying the asphalt binder with a material with a very low thermal conductivity. This method to estimate thermal conductivity of bitumen samples was found to provide an affordable alternative test procedure with good accuracy and precision.

An approximate randomization test for the high-dimensional two-sample Behrens–Fisher problem under arbitrary covariances

Summary This paper is concerned with the problem of comparing the population means of two groups of independent observations. An approximate randomization test procedure based on the test statistic of Chen & Qin (2010) is proposed. The asymptotic behaviour of the test statistic, as well as the randomized statistic, is studied under weak conditions. In our theoretical framework, observations are not assumed to be identically distributed even within groups. No condition on the eigenstructure of the covariance matrices is imposed. Furthermore, the sample sizes of the two groups are allowed to be unbalanced. Under general conditions, all possible asymptotic distributions of the test statistic are obtained. We derive the asymptotic level and local power of the approximate randomization test procedure. Our theoretical results show that the proposed test procedure can adapt to all possible asymptotic distributions of the test statistic, always has the correct test level asymptotically and has good power behaviour. Our numerical experiments show that the proposed test procedure has favourable performance compared with several alternative test procedures.

Epistaxis Requiring Intervention After Swab for SARS-CoV-2

Since May 2020, the first nasopharyngeal POC tests for SARS-CoV-2 diagnostic have been available. Due to the long passage through the nasal cavity, there is a risk of injury with subsequent epistaxis. We describe the course of disease of two female patients who suffered from massive epistaxis requiring intervention after an externally performed nasopharyngeal swab. After nasal tamponade, one patient underwent clipping of the sphenopalatine artery under general anesthesia. The other patient suffered from nasal bleeding with hemorrhagic shock requiring transfusion. She was intubated and admitted to our hospital. The nasopharyngeal swab for diagnosis of SARS-CoV-2 can lead to life-threatening complications in rare cases. Considering that daily more than 5 million corona tests are being carried out worldwide as part of the current pandemic, complications should not be neglected. It is necessary that the person performing the swab has a detailed understanding of the anatomy involved. Alternative test methods were further assessed with regard to their sensitivity. With regard to the future need for SARS-CoV-2 tests, alternative and lower-risk test procedures must be investigated and established.

Round robin test to compare flexural strength test methods for steel fiber‐reinforced sprayed concretes

AbstractAccording to the current European standard EN 14487‐1 (residual) flexural strengths of steel fiber‐reinforced sprayed concrete are determined by performing a four‐point bending test on beams according to EN 14488‐3. Controversial to this test method, a three‐point bending test on notched square panels is recommended by EFNARC. According to EFNARC, one substantial advantage of this test method is the minor scattering of the test results. Against this background, a round robin test was performed at European level. The aim was to investigate the comparability and correlation on the one hand, on the other hand to assess the precision of both test methods. The results shall provide initial pointers for the classification of the residual strengths for steel fiber‐reinforced sprayed concrete with two different test methods. The results showed that the scattering of the residual strengths is marginally smaller with the test method on panels in comparison to the test method on beams. As a result, a slightly higher precision was achieved. Therefore, the EFNARC test shall be included as an alternative test procedure in EN 14487‐1 in future.

Health-system equity, egalitarian democracy and COVID-19 outcomes: An empirical analysis.

Aims:The COVID-19 pandemic has led to a spate of studies showing a close connection between inequitable access to health care, welfare services and adverse outcomes from the pandemic. Others have argued that democratic governments have generally failed relative to more autocratic ones, simply because autocrats can make the hard choices required for stemming the spread of viruses. We address this question by asking whether more ‘egalitarian’ forms of democracy matter, given that they contain more equitable health-care access and societal infrastructure, such as social capital and trust.Methods:We use standard regression techniques, including instrumental variables analysis addressing endogeneity on COVID-19 testing and deaths data as of the end of May and beginning of September. We use novel data from the Varieties of Democracy Project on health-system equity and egalitarian democracy.Results:Our results suggest that more equitable access to health care increases testing rates and lowers the death rate from COVID-19. Broader egalitarian governance, measured as egalitarian democracy, however, shows the opposite effect. Thus, factors associated with health-care capacity to reach and treat matter more than broader societal factors associated with social capital and trust. The results are robust to alternative testing procedures, including instrumental variable technique for addressing potential endogeneity.Conclusions:Despite a great deal of public health focus on how equitable governance helps fight the adverse effects of so-called neoliberal pandemics, we find that broadly egalitarian factors have had the opposite effect on fighting COVID-19, especially when an equitable health system has been taken into account. Fighting disease, thus, might be more about the capacity of health systems rather than societal factors, such as trust in government and social capital.

Improved testing inferences for beta regressions with parametric mean link function

Beta regressions are widely used for modeling random variables that assume values in the standard unit interval, (0, 1), such as rates, proportions, and income concentration indices. Parameter estimation is typically performed via maximum likelihood, and hypothesis testing inferences on the model parameters are commonly performed using the likelihood ratio test. Such a test, however, may deliver inaccurate inferences when the sample size is small. It is thus important to develop alternative testing procedures that are more accurate when the sample contains only few observations. In this paper, we consider the beta regression model with parametric mean link function and derive two modified likelihood ratio test statistics for that class of models. We provide simulation evidence that shows that the new tests usually outperform the standard likelihood ratio test in samples of small to moderate sizes. We also present and discuss two empirical applications.

An alternative test for conditional unconfoundedness using auxiliary variables

This paper proposes an alternative test procedure for testing the conditional unconfoundedness assumption which is an important identification condition commonly imposed in the literature of program analysis and policy evaluation. We transform the conditional unconfoundedness test to a nonparametric conditional moment test using an auxiliary variable which is independent of the treatment assignment variable conditional on potential outcomes and observable covariates. The proposed test statistic is shown to have a limiting normal distribution under the null hypothesis of conditional independence. Monte Carlo simulations are conducted to examine the finite sample performances of the proposed test statistics. Finally, the proposed test method is applied to test the conditional unconfoundedness in the real example of the return to college education.

Analysis of means approach in advanced designs

AbstractAnalysis of means (ANOM), similar to Shewhart control chart that exhibits individual mean effects on a graphical display, is an attractive alternative mean testing procedure for the analysis of variance (ANOVA). The procedure is primarily used to analyze experimental data from designs with only fixed effects. Recently introduced, the ANOM procedure based on the q‐distribution (ANOMQ procedure) generalizes the ANOM approach to random effects models. This article reveals that the application of ANOM and ANOMQ procedures in advanced designs such as hierarchically nested and split‐plot designs with fixed, random, and mixed effects enhances the data visualization aspect in graphical testing. Data from two real‐world experiments are used to illustrate the proposed procedure; furthermore, these experiments exhibit the ANOM procedures' visualization ability compared with ANOVA from the point of view of the practitioner.

Extending the range of constant strain rate nanoindentation testing

Constant strain rate nanoindentation hardness measurements at high sustained strain rates cannot be made in conventional nanoindentation testing systems using the commonly employed continuous stiffness measurement technique (CSM) because of the “plasticity error” recently reported by Merle et al. [Acta Mater.134, 167 (2017)]. To circumvent this problem, here we explore an alternative testing and analysis procedure based on quasi-static loading and an independent knowledge of the Young’s modulus, which is easily obtained by standard nanoindentation testing. In theory, the method applies to any indentation strain rate, but in practice, an upper limit on the rate arises from hardware limitations in the testing system. The new methodology is developed and applied to measurements made with an iMicro nanoindenter (KLA, Inc.), in which strain rates up to 100 s−1 were successfully achieved. The origins of the hardware limitations are documented and discussed.

Statistical Inference for Least Absolute Deviation Regression with Autocorrelated Errors

The method of least absolute deviation provides a robust alternative to least squares, particularly when the data follow distributions that are non-normal and subject to outliers. While inference in least squares estimation is well understood, inferential procedures in the situation of least absolute deviation estimation have not been studied as extensively, particularly in the presence of autocorrelation. In this search, we study two alternative significance test procedures in least absolute deviation regression, along with two approaches used to correct for serial correlation. The study is based on a Monte Carlo simulation, and comparisons are made based on observed significance levels.

Dynamic-mechanical thermoanalysis test: a rapid alternative for accelerated freeze-thaw stability evaluation of W/O emulsions

Objective: The aim of this study was to develop a new dynamic-mechanical thermoanalysis (DMTA) test and evaluate its performance as rapid rheological alternative to routinely used freeze-thaw test for accelerated stability testing of water-in-oil (W/O) emulsions.Significance: Due to inherent emulsion instability and versatilities of storage and use conditions, stability assessment of emulsion products still remains complex and challenging task. Recommended stability evaluation protocols are time-consuming, imposing need for alternate test procedures, especially in the early stage of product development, as well as in the quality assurance setting, including quality control.Methods: Five model W/O emulsions were prepared, comprehensively rheologically characterized (continual and oscillatory tests), and subjected to stability evaluation through freeze-thaw test in stability chamber and DMTA tests using an air-bearing rheometer.Results: Analyzed emulsions displayed desired shear-thinning flow behavior with yield point. The storage modulus dominated over the loss modulus in the linear viscoelastic regions of amplitude sweeps, as was the case in frequency sweeps over entire frequency range. Statistical comparison showed good agreement between freeze-thaw test, as a method available and used in daily routine work for accelerated evaluation of the physical stability, and DMTA test, as a rheological simulation of the said routine method. Duration of DMTA test was significantly shorter compared to routine but lengthy freeze-thaw test (3.5 h versus 12 days).Conclusions: According to our results, DMTA test could be a rapid alternative for accelerated freeze-thaw stability evaluation of W/O emulsions, thus enabling high formulating turnover and decision making in R&D and QC departments.

Consistent production of chlorine-stressed bacteria from non-chlorinated secondary sewage effluents for use in the U.S. Environmental Protection Agency Alternate Test Procedure protocol

The U.S. Environmental Protection Agency Alternative Test Procedure protocol outlines a method to produce chlorine-stressed bacteria for water quality testing. Achieving consistent results is challenging due effluent variability. We describe a starting point for generating chlorine-stressed samples from secondary effluent to evaluate detection technologies to demonstrate comparability to EPA reference methods.