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General quality characteristics can reflect the performance and quality of equipment and have great guiding significance for the design, production, trade, and use of equipment. Maintainability, testability, and supportability (MTS) are all related to equipment faults and maintenance support and have strong relevance between them. Solving the problem of the isolation of the three characteristics evaluation requires to reduce the duplication of work and improve the evaluation efficiency, comprehensively assessment methods based on model and test are proposed by analysing the correlation of the MTS parameters. In the case study, parameters of different characteristics are obtained instead of one single characteristic, which shows the effectiveness of the proposed methods compared with the traditional sequential assessment method.

In response to the problems of many influencing factors and different indexes, a radar equipment testability assessment index system is constructed based on the characteristics of equipment and testability connotation requirements. The Criteria Importance Though the Intercrieria Correlation (CRITIC) method is improved by using the variance coefficient to replace standard deviation and conflict coefficient to calculate the absolute value, and the objective weights of evaluation indexes are determined. An improved matter-element extension model is established, and the testability evaluation of different types of radar equipment is obtained by calculating the asymmetric close degree of the extension set. The effectiveness of the model is verified by an example analysis.

The opinions and perspectives of software developers are highly regarded in software engineering research. The experience and knowledge of software practitioners are frequently sought to validate assumptions and evaluate software engineering tools, techniques, and methods. However, experimental evidence may unveil further or different insights, and in some cases even contradict developers’ perspectives. In this work, we investigate the correlation between software developers’ perspectives and experimental evidence about testability smells (i.e., programming practices that may reduce the testability of a software system). Specifically, we first elicit opinions and perspectives of software developers through a questionnaire survey on a catalog of four testability smells, we curated for this work. We also extend our tool DesigniteJava to automatically detect these smells in order to gather empirical evidence on testability smells. To this end we conduct a large-scale empirical study on 1,115 Java repositories containing approximately 46 million lines of code to investigate the relationship of testability smells with test quality, number of tests, and reported bugs. Our results show that testability smells do not correlate with test smells at the class granularity or with test suit size. Furthermore, we do not find a causal relationship between testability smells and bugs. Moreover, our results highlight that the empirical evidence does not match developers’ perspective on testability smells. Thus, suggesting that despite developers’ invaluable experience, their opinions and perspectives might need to be complemented with empirical evidence before bringing it into practice. This further confirms the importance of data-driven software engineering, which advocates the need and value of ensuring that all design and development decisions are supported by data.

It is a common saying that testing for conditional independence, that is, testing whether whether two random vectors X and Y are independent, given Z, is a hard statistical problem if Z is a continuous random variable (or vector). In this paper, we prove that conditional independence is indeed a particularly difficult hypothesis to test for. Valid statistical tests are required to have a size that is smaller than a pre-defined significance level, and different tests usually have power against a different class of alternatives. We prove that a valid test for conditional independence does not have power against any alternative. Given the nonexistence of a uniformly valid conditional independence test, we argue that tests must be designed so their suitability for a particular problem may be judged easily. To address this need, we propose in the case where X and Y are univariate to nonlinearly regress X on Z, and Y on Z and then compute a test statistic based on the sample covariance between the residuals, which we call the generalised covariance measure (GCM). We prove that validity of this form of test relies almost entirely on the weak requirement that the regression procedures are able to estimate the conditional means X given Z, and Y given Z, at a slow rate. We extend the methodology to handle settings where X and Y may be multivariate or even high dimensional. While our general procedure can be tailored to the setting at hand by combining it with any regression technique, we develop the theoretical guarantees for kernel ridge regression. A simulation study shows that the test based on GCM is competitive with state of the art conditional independence tests. Code is available as the R package GeneralisedCovarianceMeasure on CRAN.

Scientific principles can undergo various developments. While philosophers of science have acknowledged that such changes occur, there is no systematic account of the development of scientific principles. Here we propose a template for analyzing the development of scientific principles called the 'life cycle' of principles. It includes a series of processes that principles can go through: prehistory, elevation, formalization, generalization, and challenge. The life cycle, we argue, is a useful heuristic for the analysis of the development of scientific principles. We illustrate this by discussing examples from foundational physics including Lorentz invariance, Mach's principle, the naturalness principle, and the perfect cosmological principle. We also explore two applications of the template. First, we propose that the template can be employed to diagnose the quality of scientific principles. Second, we discuss the ramifications of the life cycle's processes for the empirical testability of principles.

General quality characteristics of equipment system have a guiding role for the design, production and use of equipment and are vital for the evaluation of these characteristics. They are important indicators to measure whether the equipment meets the established standard. Aiming at the problem that the design and evaluation process of equipment general quality characteristics are independent and unrelated, this paper proposes an integrated and continuous maintainability, testability and supportability design and evaluation process based on FMECA and MSFG, and designs corresponding evaluation parameters. An impact-based fault mode rating method is also proposed to better evaluate the general quality characteristics of equipment.

Calculations testing can be effectively used in the construction of discrete self-checking devices. Calculations testing is based on the parity and self-duality of the calculated functions. This can be used for modern blocks and nodes of control systems for responsible technological processes. However, its use has a number of features that must be considered when building concurrent error-detection circuits. The authors used methods of discrete mathematics and Boolean algebra as well as technical diagnostics of discrete systems to investigate the problem of ensuring the testability of the parity encoder. Theorems on the testability of convolution functions modulo 2 are proved. Considering these theorems allowed the authors of the article to propose a method for synthesizing CED circuits. This method increases the testability of the encoder for parity. This method is based on the use of two diagnostic signs at once. The first sign is that the code words belong to the parity code. The second is the self-dual control function in the concurrent error-detection circuit. This method is guaranteed to increase the testability of the parity coder compared to using one of the diagnostic signs for calculations testing. Experiments with testing discrete devices have shown the effectiveness of the organization structure of the concurrent error-detection circuit that we developed. The theorems that we proved form the basis of proof of similar provisions for the use of other linear codes in the synthesis of concurrent error-detection circuits. Our proposed solutions with calculations testing based on two diagnostic signs should be used in the synthesis of discrete systems. Discrete systems should be self-checking and have improved testability indicators.

Insertion of malicious circuits commonly known as Hardware Trojans into an original integrated circuit (IC) design to alter the functionality has been a major concern in recent years. As a result, over the years multiple techniques have been suggested by researchers to combat these malicious threats. Hard to test nets in any logic circuit are the most vulnerable to insertion of Hardware Trojans. Testability analysis is the process of identification of these hard to test nets in a logic circuit. Testability analysis is achieved through the testability metrics namely controllability and observability. Testability metrics can be used as a yardstick in devising efficient Hardware Trojan detection methods. The crux of this study is a novel method for identification of susceptible nets that are prone to Hardware Trojan insertions in a logic circuit. The study also presents a comprehensive analysis of the impact on testability parameters as a result of Hardware Trojans in the identified susceptible nets. The method utilises the testability parameters of nets to define threshold values for isolating susceptible nets in a design. The study details out the impact of the number of trigger inputs as well as the distribution of trigger nets on the testability metrics of digital circuits.

To create unit tests, it may be necessary to refactor the production code, e.g. by widening access to specific methods or by decomposing classes into smaller units that are easier to test independently. We report on an extensive study to understand such composite refactoring procedures for the purpose of improving testability. We collected and studied 346,841 java pull requests from 621 GitHub projects. First, we compared the atomic refactorings in two populations: pull requests with changed test-pairs (i.e. with co-changes in production and test code and thus potentially including testability refactoring) and pull requests without test-pairs. We found significantly more atomic refactorings in test-pairs pull requests, such as Change Variable Type Operation or Change Parameter Type. Second, we manually analyzed the code changes of 200 pull requests, where developers explicitly mention the terms \"testability\" or \"refactor + test\". We identified ten composite refactoring procedures for the purpose of testability, which we call testability refactoring patterns. Third, we manually analyzed additional 524 test-pairs pull requests: both randomly selected and where we assumed to find testability refactorings, e.g. in pull requests about dependency or concurrency issues. About 25% of all analyzed pull requests actually included testability refactoring patterns. The most frequent were extract a method for override or for invocation, widen access to a method for invocation, and extract a class for invocation. We also report on frequent atomic refactorings which co-occur with the patterns and discuss the implications of our findings for research, practice, and education

A bstract A Standard Model extension with two Majorana neutrinos can explain the measured neutrino masses and mixings, and also account for the matter-antimatter asymmetry in a region of parameter space that could be testable in future experiments. The testability of the model relies to some extent on its minimality. In this paper we address the possibility that the model might be extended by extra generic new physics which we parametrize in terms of a low-energy effective theory. We consider the effects of the operators of the lowest dimensionality, d = 5, and evaluate the upper bounds on the coefficients so that the predictions of the minimal model are robust. One of the operators gives a new production mechanism for the heavy neutrinos at LHC via higgs decays. The higgs can decay to a pair of such neutrinos that, being long-lived, leave a powerful signal of two displaced vertices. We estimate the LHC reach to this process.