Uniform Test Research Articles

Objective measures for detecting the auditory brainstem response: comparisons of specificity, sensitivity and detection time

Objective: To evaluate and compare the specificity, sensitivity and detection time of various time-domain and multi-band frequency domain methods when detecting the auditory brainstem response (ABR). Design: Simulations and subject recorded data were used to assess and compare the performance of the Hotelling’s T2 test (applied in either time or frequency domain), two versions of the modified q-sample uniform scores test and both the Fsp and Fmp, which were evaluated using both conventional F-distributions with assumed degrees of freedom and a bootstrap approach. Study sample: Data consisted of click-evoked ABRs and recordings of EEG background activity from 12 to 17 normal hearing adults, respectively. Results: An overall advantage in sensitivity and detection time was demonstrated for the Hotelling’s T2 test. The false-positive rates (FPRs) of the Fsp and Fmp were also closer to the nominal alpha-level when evaluating statistical significance using the bootstrap approach, as opposed to using conventional F-distributions. The FPRs of the remaining methods were slightly higher than expected. Conclusions: In this work, Hotelling’s T2 outperformed the alternative methods for automatically detecting ABRs. Its promise as a sensitive and efficient detection method should now be tested in a larger clinical study.

Lateral-distortional buckling of beams with hollow flanges and folded plate webs

This paper is concerned with the effects of distortion on the lateral buckling of steel beams which have rectangular or square hollow flanges and folded plate webs. The hollow flanges potentially make very large contributions to the torsional stiffness, but flange distortion (in a shear mode) causes a significant reduction in the effective torsional stiffness and in the lateral buckling resistance.In this paper, the shear distortion of the hollow flanges is analysed, and the strain energy stored in a distorted flange is compared with the strain energy stored during uniform torsion of the flange. This comparison allows the development of a suitable parameter for use in the evaluation of the effect of flange distortion on the torsional stiffness of a hollow flange beam. Uniform torsion test results are used to confirm the significance of this parameter.Finite strip analyses of simply supported hollow flange beams in uniform bending show that there is a significant interaction between distortion and uniform torsion during lateral buckling, which may be approximated by combining their flexibilities. More accurate finite element analyses show that the finite strip predictions are conservative. An approximate method of predicting the effects of flange distortion on elastic lateral buckling is presented which shows good agreement with the finite element predictions.

Multi-phase arrival tracking using tetrahedral cells within a 3D layered titled transversely isotropic anisotropic model involving undulating topography and irregular interfaces

To overcome a major problem in current ray tracing methods, which are only capable of tracing first arrivals, and occasionally primary reflections (or mode conversions) in regular cell models, we extend in this paper the multistage triangular shortest-path method (SPM) into 3D titled transversely isotropic (TTI) anisotropic media. The proposed method is capable of tracking multi-phase arrivals composed of any kind of combinations of transmissions, mode conversions and reflections. In model parameterization, five elastic parameters, plus two angles defining the titled axis of symmetry of TTI media are sampled at the primary nodes of the tetrahedral cell, and velocity value at secondary node positions are linked by a tri-linear velocity interpolation function to the primary node velocity value of that of a tetrahedral cell, from which the group velocities of the three wave modes (qP, qSV and qSH) are computed. The multistage triangular SPM is used to track multi-phase arrivals. The uniform anisotropic test indicates that the numerical solution agrees well with the analytic solution, thus verifying the accuracy of the methodology. Several simulations and comparison results for heterogeneous models show that the proposed algorithm is able to efficiently and accurately approximate undulating surface topography and irregular subsurface velocity discontinuities. It is suitable for any combination of multi-phase arrival tracking in arbitrary tilt angle TTI media and can accommodate any magnitude of anisotropy.

Investigation on the Sulfuric Acid Corrosion Mechanism for Concrete in Soaking Environment

This paper chooses the apparent diffusion coefficient for OH− (hydroxyl ion) for concrete as an index to evaluate the corrosion degree of concrete subjected to sulfuric acid. Based on the reaction boundary layer theory, a sulfuric acid corrosion model for concrete was established and verified through experiments. The experiment design and data processing of sulfuric acid corrosion tests for concrete were carried out using uniform test design and nonparametric regression. Effects of water‐cement ratio and pH value are presented on the sulfuric acid corrosion mechanism for concrete. Test results show that when the pH value was 2.50, the sulfuric acid corrosion degree of concrete was the most serious. The boundary layer effect always existed in the sulfuric acid corrosion for concrete, and the corrosion process included rapid and stable corrosion stages. The apparent diffusion coefficient for OH− for concrete increased with the decrease of pH value and the increase of water‐cement ratio and cement proportion.

Innovation, cooperation, and the structure of three regional sustainable agriculture networks in California

Regional agroecological systems are examples of complex adaptive systems, where sustainability is promoted by social networks that facilitate information sharing, cooperation, and connectivity among specialized components of the system. Much of the existing literature on social capital fails to recognize how networks support multiple social processes. Our paper overcomes this problem by analyzing how the social networks of wine grape growers exhibit structural features related to multiple social processes: ties to central actors that build bridging social capital and facilitate the diffusion of innovations, ties that close triangles and build bonding social capital to solve cooperation dilemmas, and ties to individuals that span community boundaries to connect specialized components of the system. We use survey data to measure the communication networks of growers in three viticulture regions in California. A combination of descriptive statistics, conditional uniform random graph tests, and exponential random graph models provides empirical support for our hypotheses. The findings reflect regional differences in geography and institutional histories, which may influence the capacity to respond to regional environmental change.

A class of uniform tests for goodness-of-fit of the multivariate $$L_p$$Lp-norm spherical distributions and the $$l_p$$lp-norm symmetric distributions

In this paper we employ the conditional probability integral transformation (CPIT) method to transform a d-dimensional sample from two classes of generalized multivariate distributions into a uniform sample in the unit interval $$(0,\,1)$$ or in the unit hypercube $$[0,\,1]^{d-1}$$ ( $$d\ge 2$$ ). A class of existing uniform statistics are adopted to test the uniformity of the transformed sample. Monte Carlo studies are carried out to demonstrate the performance of the tests in controlling type I error rates and power against a selected group of alternative distributions. It is concluded that the proposed tests have satisfactory empirical performance and the CPIT method in this paper can serve as a general way to construct goodness-of-fit tests for many generalized multivariate distributions.

Uniform Test Method Optimum Design for Drag-Type Modified Savonius VAWTs by CFD Numerical Simulation

This paper reports the results of optimizing design of the drag-type modified Savonius VAWTs with 4, 5 and 6 blades by using uniform test method. The optimal design is performed in the light of wind energy utilization rate as the goal function and conducted by numerical simulation for drag-type modified Savonius VAWTs with 4, 5 and 6 blades; the FLUENT software, sliding grid technology and PISO algorithm are employed in the process. In the optimization, the blade width, the blade installation angle and the rotation rate of windmill are taken as the basic parameters. The results indicated that the optimal wind energy utilization rate is $${C}_{\mathrm{p}} = 27.140\%$$ for the 4-blade turbine at the blade width $$d = 0.882\,\hbox {m}$$ , blade installation angle $$\theta = 24.895^{\circ }$$ and the windmill rotation rate $$\omega =17.206 \,\hbox {r}/\hbox {min}$$ ; the optimal wind energy utilization rate is $${C}_{\mathrm{p}}=28.493\%$$ for the 5-blade turbine at $$d = 0.803\,\hbox {m}$$ , $$\theta =17.425^{\circ }$$ and $$\omega =16.265\, \hbox {r}/\hbox {min}$$ ; the optimal wind energy utilization rate is $${C}_{\mathrm{p}}= 30.564\%$$ for the 6-blade turbine at $$d = 0.681\,\hbox {m}$$ , $$\theta = 21.650^{\circ }$$ , $$\omega = 18.369\, \hbox {r}/\hbox {min}$$ .

A tuned version of genetic algorithm for efficient test suite generation in interactive t-way testing strategy

ContextTo improve the quality and correctness of a software product it is necessary to test different aspects of the software system. Among different approaches for software testing, combinatorial testing along with covering array is a proper testing method. The most challenging problem in combinatorial testing strategies like t-way, is the combinatorial explosion which considers all combinations of input parameters. Many evolutionary and meta-heuristic strategies have been proposed to address and mitigate this problem. ObjectiveGenetic Algorithm (GA) is an evolutionary search-based technique that has been used in t-way interaction testing by different approaches. Although useful, all of these approaches can produce test suite with small interaction strengths (i.e. t ≤ 6). Additionally, most of them suffer from expensive computations. Even though there are other strategies which use different meta-heuristic algorithms to solve these problems, in this paper, we propose an efficient uniform and variable t-way minimal test suite generation approach to address these problems using GA, called Genetic Strategy (GS). MethodBy changing the bit structure and accessing test cases quickly, GS improves performance of the fitness function. These adjustments and reduction of the complexities of GA in the proposed GS decreases the test suite size and increases the speed of test suite generation up tot=20. ResultsTo evaluate the efficiency and performance of the proposed GS, various experiments are performed on different set of benchmarks. Experimental results show that not only GS supports higher interaction strengths in comparison with the existing GA-based strategies, but also its supported interaction strength is higher than most of other AI-based and computational-based strategies. ConclusionFurthermore, experimental results show that GS can compete against the existing (both AI-based and computational-based) strategies in terms of efficiency and performance in most of the case studies.

PENGEMBANGAN TABLET EFERVESEN KOMBINASI BROKOLI DAN PEGAGAN DENGAN KOMBINASI ASAM DAN BASA

Brocoli and pegagan is a plant that is easy to get and efficacious as antidemensia. The objective of this study was to formulate the plant into an effervescent tablet preparation and to determine the best formula with acid concentration variation. Dry extract of brocoli and pegagan is made by the method of escape then dried with vacuum dryer. The preparation is made by wet granulation method of 3 formula with weight of 4 gram per tablet. The granule test includes moisture content. Result of granule water content ˂5%. Granules are printed in special chambers and conditions and tested for quality. The result of uniform weight test of all formula meets the requirements of Pharmacopoeia Indonesia III; Hardness of tablets 12.06-12.52 kP; Friability of tablets 0.083-0.74%; Test of dissolution time of efervesen tablet ˂ 5 minutes. Preferred test results showed formula III with citric acid concentration: 1: 2 tartaric acid most preferred; Test result of asiatikosida content of pegagan extract is 0.08% and efervesen 0.005% tablet; Test results for vitamin C content of broccoli extract 13.859% and efevesen tablet 16.995%. The results of the physical quality test of effervescent tablets showed that the three formulas met the specified requirements. Stability test results for 8 weeks showed that the effervesen tablet of formula 3 met the requirements of physical quality during storage.

A newly developed rapid uniform thermal cycle test system for electronic components

Electronic components are difficult to heat or cool uniformly and rapidly because of the low heat conduction properties of the materials used in these components. The present study reports a new rapid thermal fatigue test system that circulates a temperature-controlled air shower around test samples to realize both uniform and rapid temperature control. Since the proposed test system allows multi-unit integration of multiple test chambers, the simultaneous evaluation of several samples under various test conditions can be performed efficiently. Based on the results of the temperature profile measured for a practical electronic circuit board, the proposed system is confirmed to enable the target temperature to be approached rapidly while maintaining a uniform temperature distribution. The proposed system shortens the thermal cycle period from 60min to 12min while generating the same degree of crack damage and the same fracture mode of solder joints.

On the Possibility of Preferred Performance Styles and Their Link to Learning Styles

The existence of individual learnings styles is a hot topic in contemporary education theory and practice. There is an on-going debate on whether learners benefit from teaching methods that are tailored to their perceived learning styles. The majority of educators believe that such styles do exist and a striving industry benefits from this concept. However, experts conclude that the evidence on this matter provides no support for the utility of learning styles. In this manuscript we briefly review this debatable topic and focus on a key flaw in the analyses of learning styles. We indicate that the current models for the evaluation of such styles call for different instruction methods and a uniform test. However, the possibility that learner styles correlate to different performance in different types of examination has not been experimentally addressed. We discuss this discrepancy and propose methodologies that can identify such preferred performance styles.

Quality Assurance of Solid Oxide Fuel Cell (SOFC) and Electrolyser (SOEC) Stacks

Many research facilities and industrial companies worldwide are engaged in the development and the improvement of solid oxide fuel cells/stacks (SOFC) and also of solid oxide electrolysis cells/stacks (SOEC). However, the different stacks cannot be easily compared due to non-standardized test programs. Therefore the EU-funded project “SOCTESQA” which started in May 2014 has the aim to develop uniform and industry wide test modules and programs for SOC cells/stacks. New application fields which are based on the operation of the SOC cell/stack assembly in the fuel cell (SOFC), in the electrolysis (SOEC) and in the combined SOFC/SOEC mode are addressed. This covers the wide range of power generation systems, e.g. stationary SOFC µ-CHP, mobile SOFC auxiliary power unit (APU) and SOFC/SOEC power-to-gas systems. In order to optimize the test programs, which consist of different test modules, several testing campaigns have been performed. The project partners apply the developed test procedures on identical SOC stacks. In this project 5-cell short-stacks with anode supported cells (ASC) were used, which were provided by an established stack supplier. Altogether 10 pre-normative test modules were developed: Start-up, current-voltage curve, electrochemical impedance spectroscopy, reactant utilization, reactant gas composition, temperature sensitivity, operation at constant current, operation at varying current, thermal cycling and shut-down. The presentation compares the results of the test modules of the different project partners. Important aspects are the evaluation of the results in terms of repeatability of the different testing campaigns and the reproducibility of the results among the partners. Electrochemical properties, e.g. open circuit voltage (OCV), area specific resistance (ASR), power density, fuel utilization (FU) and impedance values of both stack and repeat units (RU) are presented. Moreover, the results are discussed in context to the test input parameters. Another important issue is the reproducibility of the different test methods, e.g. jV-characteristics and EIS-spectra. Finally, important aspects for the determination of reproducible degradation rates of SOC stacks will be presented and discussed.

Layered effects on soil displacement around a penetrometer

The interpretation of cone penetration test (CPT) data is important for the in-situ characterisation of soils. Interpretation of CPT data remains a predominately empirical process due to the lack of a rigorous model that can relate soil properties to penetrometer readings. Interpretation is especially difficult in layered soils, where penetrometer response can be affected by several horizons of soil with different properties. This paper aims to provide some insight into the mechanisms of soil displacement that occur as a penetrometer is pushed into layered soils. Data is presented from centrifuge modelling of probe penetration in layered soils in an axisymmetric container where soil deformation patterns around the probe can be measured. Results obtained from uniform soil tests are also presented to illustrate the effects of soil density and stress level (i.e. centrifuge acceleration). A large influence zone is found to relate to the higher penetration resistance obtained in a denser soil. Differing soil displacement patterns at low and high stresses are related to the tendency of the soil to dilate, with the well-known consequence of a non-linear increase of penetration resistance with stress level. Layered soil tests show a clear difference of soil deformation patterns compared to uniform tests, especially for vertical displacements. The peak value of vertical displacement of the soil occurs at dense-over-loose interfaces, while a local minimum occurs at loose-over-dense interfaces. Parameters are proposed to quantitatively evaluate the layered effects on soil deformations and a deformation mechanism is described for penetration in layered soils based on the transition of displacement profiles.

Direct numerical simulation of particulate flows with an overset grid method

We evaluate an efficient overset grid method for two-dimensional and three-dimensional particulate flows for small numbers of particles at finite Reynolds number. The rigid particles are discretised using moving overset grids overlaid on a Cartesian background grid. This allows for strongly-enforced boundary conditions and local grid refinement at particle surfaces, thereby accurately capturing the viscous boundary layer at modest computational cost. The incompressible Navier–Stokes equations are solved with a fractional-step scheme which is second-order-accurate in space and time, while the fluid–solid coupling is achieved with a partitioned approach including multiple sub-iterations to increase stability for light, rigid bodies. Through a series of benchmark studies we demonstrate the accuracy and efficiency of this approach compared to other boundary conformal and static grid methods in the literature. In particular, we find that fully resolving boundary layers at particle surfaces is crucial to obtain accurate solutions to many common test cases. With our approach we are able to compute accurate solutions using as little as one third the number of grid points as uniform grid computations in the literature. A detailed convergence study shows a 13-fold decrease in CPU time over a uniform grid test case whilst maintaining comparable solution accuracy.

Estimation and Inference of Distributional Partial Effects: Theory and Application

ABSTRACTThis article considers nonparametric and semiparametric estimation and inference of the effects of a covariate, either discrete or continuous, on the conditional distribution of a response outcome. It also proposes various uniform tests following estimation. This type of analysis is useful in situations where the econometrician or policy-maker is interested in knowing the effect of a variable or policy on the whole distribution of the response outcome conditional on covariates and is not willing to make parametric functional form assumptions. Monte Carlo experiments show that the proposed estimators and tests are well-behaved in small samples. The empirical section studies the effect of minimum wage hikes on household labor earnings. It is found that the minimum wage has a heterogenous impact on household earnings in the U.S. and that small hikes in the minimum wage are more effective in improving the household earnings distribution.

Pipeline internal corrosion monitoring based on distributed strain measurement technique

Pipeline corrosion is an important issue that threatens the pipeline safety operation; therefore, the corrosion monitoring is essential. Based on the optical frequency domain reflectometry technology, which features distributed strain measurement with high resolution and high precision, a new method of pipeline internal corrosion monitoring is proposed to simultaneously locate corrosion and to evaluate corrosion severity. To verify the effectiveness and accuracy of this method, a series of tests were conducted including uniform corrosion test and local corrosion tests. These test results demonstrate that the corrosion location and corrosion severity evaluation can be achieved via the proposed distributed strain measurement, providing a valuable approach for pipeline corrosion monitoring.

Undrained behavior of sand under cyclic paths that match storm-wave loading conditions

ABSTRACTIn ocean engineering, storm-wave loading imposes irregular cycles in the magnitudes acting on the coastal or seabed cohesionless soils, giving rise to more complex consequences on the their liquefaction susceptibility, compared with those under uniform cyclic loadings that were considered in most routine engineering designs. This paper presents a systematic experimental investigation into the undrained behavior of saturated loose sand subjected to irregular cyclic triaxial paths that match the storm-wave loading conditions, with the presence of static shear stress that mimics the initial condition of sand deposits in the field, along with the conventional uniform cyclic triaxial tests for comparison. The results indicate that both the initial static stress and the cyclic irregularity influence the pore pressure development and cyclic resistance of sand. When the static shear stress presents, the sand samples under storm-wave loading show a monotonic increase in cyclic resistances to liquefaction. In addition, the concept of strain energy is used to delineate the accumulation of pore pressure during cyclic loading. A unique relationship between the normalized pore pressure and the strain energy is observed, irrespective of the static stress level, cyclic stress amplitude, and applied cyclic loading patterns.

Quantitative Flow Cytometry: Concerns and Recommendations in Clinic and Research.

Quantitative flow cytometry (QFCM) can be an important element within the developing toolbox for clinical diagnostics which relies on precise and rapid tests that provide a conclusive answer for physicians. The FC technology combines all of these features. Until recently, this imperative discipline was based on qualitative assessments of cell populations. However, due to the enormous advancement in FC technology, which allows the quantification of a number of antigens on cell surface and within the cells by units of median fluorescence intensity (MFI), this method becomes meaningful and fits the clinical needs. On the basis of our experience in the field of quantitative FC, we wish to highlight some of the key concerns related to this methodology and suggest possible solutions for achieving uniform and standardized QFCM tests based on MFI. Several parameters are responsible for inter and intra laboratory variations. The standardization of quantitative FC relies on three major components; Samples and reagents handling, FC maintenance and data analysis. The use of specialized beads as a part of the routine calibration process lowers inter-test variability between different operators and different FC instruments. Similarly, the use of agreed biological controls contributes significantly to lowering test variability. The field of QFCM displays a significant part in the diagnostic clinical toolbox. We believe that the recommendations described herein can improve significantly the stability and accuracy of this method, thus assuring a more standardized cell analyses. © 2017 International Clinical Cytometry Society.

Corrosion behaviour of Aluminium Metal Matrix reinforced with Multi-wall Carbon Nanotube

Compared to other alloys of Aluminium, AA5083 alloy is one of the most promising material which is used in corrosive and cryogenic environment. The effect of the purity and weight percentage of Multi-wall Carbon Nanotube (MWCNT) added to the Aluminium alloy is the widely focused research area in the field of Cryogenics in recent years. In this present work, MWCNT having more than 98% purity, 5–20 nm mean diameter (D) and 1–10 μm average length (L) was used with different compositions like 1, 1.25, 1.5 and 1.75 by weight % to improve the corrosion behaviour of the Aluminium Nano Metal Matrix Composite (ANMMC). The results show Aluminium alloy AA5083 reinforced with MWCNT exhibit nominal changes in density than pure AA5083 and the uniform immersion corrosion tests (ASTM-G31) of the same composite in 90 ml of HCl shows increase in corrosion resistance as compared to AA5083 alloy.

Uniform Test Assembly: Concepts, Problems, Solvers, and Applications for Adaptive Testing

Uniform Test Assembly: Concepts, Problems, Solvers, and Applications for Adaptive Testing