Comparative Study Of Tests Research Articles

Cyber Security of Smart Metering Infrastructure Using Median Absolute Deviation Methodology

To combat cyber threats in the smart grid, an intrusion detection system can be integrated into the advanced metering infrastructure. Anomaly-based intrusion detection can detect even the tiniest changes in the parameter under investigation, whereas signature-based intrusion detection only recognises known attacks. The growing usage of smart grids necessitates the classification, identification, and implementation of countermeasures to threats. At the absolute least, smart grids must be protected against cyberattacks; thus, the highest level of information security must be offered. As a result of digitisation and the usage of more smart applications, the research looked at a variety of attack types, smart grid assaults, and major cyber threats on the voltage regulation. Machine learning techniques that analyse data in real time and formulate patterns to recognise an attack and scan through huge data for anomalies can be implemented into the advanced metering infrastructure (AMI) for intrusion detection for anomaly-based intrusion detection. The comparative test study done for the research found that the proposed method, median absolute deviation for anomaly identification in smart metering datasets, produced the most accurate and precise differentiations with the highest accuracy and precision. The median absolute deviation (MAD) algorithm model is trained using test data, and raw predictions are made, before true data are used to derive final test result parameters, precision, recall, and F1 scores. The methodology of the entire study is discussed in this paper, as well as how the MAD algorithm is best suited for anomaly-based intrusion detection, as well as result comparisons of other machine learning algorithms.

Thermal insulation materials in architecture: a comparative test study with aerogel and rock wool.

Thermal insulation has great potential to reduce energy consumption in buildings. This study aims to provide a general perspective by addressing the thermal insulation materials used throughout the history of the construction industry and to understand the current situation with developing technology. The literature review was used as a method in the study. The insulation values of current thermal insulation products were investigated and compared. An energy loss and gain analysis were carried out on the Revit-2019 model to understand the difference between the widely used rock wool and a nanotechnology product, aerogel-added thermal insulation material. In addition, the effect of the use of these products on the building cost is emphasized. The results of the study show that thermal insulation materials produced with nanotechnology examined have lower thermal conductivity coefficients compared to other thermal insulation materials. According to the analysis carried out on the Revit-2019 (Autodesk Revit Architecture/3D) model, the thermal insulation material with aerogel provides 8% savings in cooling loads compared to the use of rock wool. As a result of the analysis made on the Revit-2009 model, it was concluded that 8% savings were achieved in cooling loads in the use of aerogel-added materials compared to the use of rock wool, but the initial investment cost was high. Developing competitive and sustainable materials is of the utmost importance. The literature review suggests that new composite insulators can be produced by combining suitable materials.

A Comparative Study of Test Equating Methods Based on Item Response Theory Using Monitor Examinee Groups For Each Test Administration

A Comparative Study of Test Equating Methods Based on Item Response Theory Using Monitor Examinee Groups For Each Test Administration

Pulmonary Artery Hypertension in Acyanotic Congenital Heart Disease Underwent Transcatheter Closure at Dr. Soetomo Hospital

Background: Pulmonary artery hypertension (PAH) is common complication of congenital heart disease.Echocardiography before and after transcatheter closure procedure is needed for further evaluation.Objective: To evaluate the PAH before and after transcatheter closure procedure by echocardiography atDr. Soetomo Hospital.Methods: Medical record patients with acyanotic congenital heart disease with PAH and already donetranscatheter closure procedure in 2010 – 2014 were reviewed. Data taken were demographic, clinical,and echocardiography. Tricuspid regurgitation pressure gradient (TRPG) was evaluated. Statistical analysisusing t test comparative study; P<0.05 was considered significant.Results: There were 46 patients underwent transcatheter closure, ASD closure 22/46, VSD closure 16/46,PDA closure 8/46 patients. Ten patients with PAH (10/46), 4/10 ASD, 4/10 PDA and 2/10 VSD. Boys were6/10, median age was 60 (range 4-144 months). Median TRPG before procedure was 32.4 (range 25-43mmHg). Median TRPG after procedure was 21.5 (range 15-26.9 mmHg). There was significant decreased inPAH after transcatheter closure procedure (P=0.01).Conclusion: Transcatheter closure procedure in acyanotic congenital heart disease was important fordecreasing the pressure gradient of PAH.

A Comparative Study of Test Takers’ Performance on Computer-Based Test and Paper-Based Test Across Different CEFR Levels

Computer-based test (CBT) and paper-based test (PBT) are two test modes to the test takers that have been widely adopted in the field of language testing or assessment over the last few decades. Due to the rapid development of science and technology, it is a trend for universities and educational institutions striving rather hard to deliver the test on a computer. Therefore, research on the comparison between these two test modes has attracted much attention to investigate whether the PBT could be completely replaced. At the same time, task difficulty is always a key element to reflect test takers’ performances. Numerous studies have laid a solid foundation and guidance about the comparative study of test takers’ performance on CBT and PBT, but there still remains a scarcity from the perspective of task difficulties with different Common European Framework of Reference for Languages (CEFR) task levels in particular.
 This study, therefore, compared the test takers’ performance on both CBT and PBT across tasks with different CEFR levels. A total of 289 principal recommended high school test takers from Macau took the pilot Test of Academic English (TAE) at a local university. The results indicated that there was a difference between test takers’ performance on different test modes across different CEFR levels, but only CEFR A2 level showed a statistically difference between CBT and PBT. And since science and technology are continuously developing, it is essential for the university to consider switching the test mode from PBT to CBT.

A Comparative Test Study of the Impact Performances of Stainless-Steel Rebar Equal-Strength Replacement Piers

It has been found that there are rebar instability and construction complexity phenomena associated with the replacements of ordinary pier rebars with stainless-steel rebars of equal piece numbers and strength. Therefore, this study explored the issues of the equal-strength replacements of stainless-steel pier rebars with different distributions. The study utilized the most advanced domestic multi-function super-high heavy hammer impact test system available, and conducted a comparative test of the horizontal impact results of two groups of pier models with 1/5 contraction scales. The purpose of the testing was to analyze the impact force, impact displacement, strain time history curve, crack propagation and distribution, ultrasonic damages to the concrete, and so on. The test results showed the following: The original specimen displayed a consistent variation trend with the equal replacement specimen of the stainless-steel rebar of different distributions from the aspects of the maximum impact force, strain of the rebar and concrete, displacement peak, and so on, under the conditions of continuous multiple impacts. The relative variation rate was found to be within the scope of ± 10% under equal impact energy. The quantity and distribution of the cracks, as well as the concrete damages, were also found to be approximately consistent under equal impact energy. Therefore, in this study, it was considered to be feasible for the solution of the problems related to rebar corrosion, strength surplus, resource waste, and so on, to replace ordinary pier rebars with stainless-steel rebars with equal-strength and different distributions.

A Comparative Test Study on the Seismic Damage Sustained by Frame‐Core Tube Structures

The overall damage sustained by a structure can be controlled in the current damage‐based seismic design, but the rationality of the relationship among the damage states of the components in the structure and the influences of those states on the overall seismic performance of the structure are currently ignored. In response to this problem, a comparative test was performed in this paper to study the seismic damage performances of two frame‐core tube structure models, namely, an optimization model designed through the optimization of the component damage states to achieve the relationship among those damage states proposed in this paper and a normative model designed through the seismic design method based on Chinese codes. By comparing the experimental data of these two models, the relationship among the component damage states was discussed comprehensively, and the influences of those states on the overall seismic performance of the frame‐core tube structure were analyzed. The proposed relationship among the component damage states in the optimization model can effectively limit the development of overall damage and improve the internal force response of the structure.

An update on ‘a comparative study of tests for homogeneity of variance’

ABSTRACTTests for equality of variances using independent samples are widely used in data analysis. Conover et al. [A comparative study of tests for homogeneity of variance, with applications to the outer continental shelf bidding data. Technometrics. 1981;23:351–361], won the Youden Prize by comparing 56 variations of popular tests for variance on the basis of robustness and power in 60 different scenarios. None of the tests they compared were robust and powerful for the skewed distributions they considered. This study looks at 12 variations they did not consider, and shows that 10 are robust for the skewed distributions they considered plus the lognormal distribution, which they did not study. Three of these 12 have clearly superior power for skewed distributions, and are competitive in terms of robustness and power for all of the distributions considered. They are recommended for general use based on robustness, power, and ease of application.

Performance Comparative Test Study on Disk and Drum Brake Mounted in Semitrailer

The braking performance of large-scale freight vehicle is an important influencing factor to braking safety. Presently, the utility ratio of disk brake in large-scale freight vehicle is low. In this paper, comparative test study on disk and drum brake mounted in semitrailer is conducted, including building and installing methods of the test system, test method and evaluation of test result. The test result shows that the disk brake can provide semitrailer with larger brake torque and better thermal stability. It is of more obvious advantages than drum brake.

Experimental Study on Thermal Decay Performance of Disk and Drum Brake

The braking thermal decay performance of large-scale freight vehicle is an important influencing factor to braking safety. Presently, the utility ratio of disk brake in large-scale freight vehicle is low. In this paper, thermal decay performance comparative test study on disk and drum brake mounted in semitrailer is conducted. The test result shows that During the thermal decay test, the temperature change of disk brake is small in less than 150℃ and big more than 150℃. Temperature change of drum bake is more stable. The disk brake can provide semitrailer with larger brake torque and better thermal stability. It is of more obvious advantages than drum brake.

Computer-based vs. Paper-based Writing Tests: A Comparative Study of Test Taking Strategies

This study was an attempt to compare the use of test taking strategies in computer-based writing test (CBWT) and paper-based writing test (PBWT) in an Iranian context. To that end, the researchers selected 30 test takers from Payam-Nour University of Shabestar and assigned them into two groups i.e. the CBWT group ( n =15) and PBWT group ( n =15). The participants in both groups took a writing test and produced verbal reports. Collecting the data, the researchers coded the verbal reports based on Mu's(2005) taxonomy of ESL writing strategies. The result showed that test takers in both groups were similar in the use of top four sub-strategies (i.e. organization, planning, sense of readers and revising). Also, it was known that both groups did not draw on two types of social/affective strategies (resourcing and summarizing) and on one kind of cognitive strategies (summarizing). This study contributes to the language testing field in several ways: (a) by providing insight into individual differences among test takers, and (b) by revealing the importance of test taker differences in different test administration modes. Overall, the findings may be beneficial not only to test-takers but also to test developers and administrators in particular. The conclusions and recommendations for future studies are discussed accordingly.

Improving dispersion tests by symmetrization

Comparing the variances of several independent samples is a classic problem and many tests have been proposed in the literature. Conover et al. [Conover, W.J., Johnson, M.E. and Johnson, M.M., 1981, A comparative study of tests for homogeneity of variances with applications to the outer continental self bidding data. Technometrics, 23, 351–361.] and Shoemaker [Shoemaker, L.H., 1995, Tests for difference in dispersion based on quantiles. The American Statistician, 49(2), 179–182.] find that the existing tests lack power for skewed sampling distributions. To address this problem, we studied the effect of an a priori symmetrization of the data on the performance of tests for homogeneity of variances. This article also updates the comprehensive comparative study of Conover et al.

A comparative study of tests for paired lifetime data

In this paper, we investigate different procedures for testing the equality of two mean survival times in paired lifetime studies. We consider Owen's M-test and Q-test, a likelihood ratio test, the paired t-test, the Wilcoxon signed rank test and a permutation test based on log-transformed survival times in the comparative study. We also consider the paired t-test, the Wilcoxon signed rank test and a permutation test based on original survival times for the sake of comparison. The size and power characteristics of these tests are studied by means of Monte Carlo simulations under a frailty Weibull model. For less skewed marginal distributions, the Wilcoxon signed rank test based on original survival times is found to be desirable. Otherwise, the M-test and the likelihood ratio test are the best choices in terms of power. In general, one can choose a test procedure based on information about the correlation between the two survival times and the skewness of the marginal survival distributions.

A comparative study of tests for the difference of two Poisson means

We investigate different test procedures for testing the difference of two Poisson means. Asymptotic tests, tests based on an approximate p-value method, and a likelihood ratio test are considered. Size and power performance of these tests are studied by means of Monte Carlo simulation under different settings. If one wants to control the actual significance level at or below the pre-chosen nominal level, tests based on approximate p-value method are the desirable candidates. If one allows tests whose actual significance levels may occasionally exceed the pre-chosen nominal level by an acceptable margin, asymptotic tests based on an unbiased estimate and constrained maximum likelihood estimate are reasonable alternatives. We illustrate these testing procedures with a breast cancer example.

A comparative study of tests of cardiac parasympathetic nervous activity in healthy human subjects

Conventional tests of cardiac parasympathetic nervous system (PNS) activity were compared with the high frequency component of the heart rate power spectrum in a heterogenous group of normal subjects encompassing a wide age range. The data suggest that the linear associations between the various conventional tests of parasympathetic nervous activity even when statistically significant, were relatively modest, with r values ranging from 0.23 to 0.53. Three of the five conventional tests of parasympathetic nervous activity were significantly correlated (r = 0.33 to 0.46) with the absolute high frequency power of RR variability. However, these relationships were poorer and non-significant when the high frequency power spectrum was normalized for total power (r = 0.06 to 0.19, NS). An evaluation of the heart rate responses to cough and a single maximal hand grip indicated that the responses were repeatable but that the extent to which these manoeuvres induced vagally mediated cardioacceleration was significantly lesser than the other conventional tests of PNS activity. Taken together, the data suggest that despite the advent of heart rate variability measures, it is advisable to use multiple tests of parasympathetic nervous activity while evaluating autonomic dysfunction, since, despite the specificity of the tests, there is a variable correlation between them.

Comparative Study of Tests for Flour Quality Evaluation in the Breeding of 1BL/1RS Translocation Wheats

The correct evaluation of the breadmaking quality of 1BL/1RS wheat-rye translocation lines in breeding programs requires the use of tests which are most suitable to the peculiarities of these materials. The SDS-sedimentation test, the Pelshenke index, the 10-gram mixograph and the Chopin microalveograph have been jointly used in four sets of F3–F4 lines, descending from crosses between wheat cultivars with and without the 1BL/1RS translocation. The parameter measured by the mixogram which was most positively related to dough strength was height 3 minutes after reaching the peak (H3). The values of H3 were relatively independent from quality parameters slightly influenced by the presence-absence of the translocation such as optimum mixing time and tolerance range. The predictive value of the flour quality of the Pelshenke index and SDS-sedimentation volume varied according to the genetic background. The use of the Pelshenke test in selection processes results in a lower loss of potentially good-quality genotypes. The relative independence of the values obtained in the two tests regarding protein content, recommends the use of both tests together as selection indices in early generations of 1BL/1RS materials.

A comparative study of tests of independence

This paper deals with six test statistics, of independence of row and column classifications in an(rxc) contingency table. Since their distributions are not easy to obtain, a simulation procedure is used to simulate their percentiles. Four new modified test statistics have been suggested. A power comparison has been conducted and it shows that some of these tests are as good as the usual chi-square, and sometimes they are more powerful than the chi-square test.

Corrigendum: A Comparative Study of Tests for Homogeneity of Variances, with Applications to the Outer Continental Shelf Bidding Data

Corrigendum: A Comparative Study of Tests for Homogeneity of Variances, with Applications to the Outer Continental Shelf Bidding Data

A Comparative Study of Tests for Homogeneity of Variances, with Applications to the Outer Continental Shelf Bidding Data

Many of the existing parametric and nonparametric tests for homogeneity of variances, and some variations of these tests, are examined in this paper. Comparisons are made under the null hypothesis (for robustness) and under the alternative (for power). Monte Carlo simulations of various symmetric and asymmetric distributions, for various sample sizes, reveal a few tests that are robust and have good power. These tests are further compared using data from outer continental shelf bidding on oil and gas leases.

A Comparative Study of Tests for Homogeneity of Variances, with Applications to the Outer Continental Shelf Bidding Data

A Comparative Study of Tests for Homogeneity of Variances, with Applications to the Outer Continental Shelf Bidding Data