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Measuring and testing the scalability and performance of cloud-based software services is critical for the delivery of such services, and the development of cloud computing. There are three interconnected Cloud-based software services' performance aspects; both elasticity and efficiency are depending on the delivery of a sufficient level of scalability performance. In this work, we focused on testing and measuring the cloud-based software services scalability from a technical perspective. This paper uses technical scalability metrics that address both volume and quality scaling, inspired by earlier technical metrics of elasticity. We demonstrate the application of the metrics using a practical example and three demand scenarios and discuss the importance of these metrics. We show how our technical scalability metrics integrated into an earlier utility-oriented metric of scalability, in order to enable the scalability analysis from technical and production-driven perspectives. This work is related to the delivery of cloud-based software services from scalability perspective. We demonstrate our metrics by testing a cloud-based software service connecting with both AWS auto-scaling and load-balancing services. Measurements have been collected and analysis, and then been used to calculate the values of our scalability metrics. [ABSTRACT FROM AUTHOR]

This article discusses the use of the Many-Facets Rasch Model, via the FACETS computer program (Linacre, 2006a), to scale job/practice analysis survey data as well as to combine multiple rating scales into single composite weights representing the tasks’ relative importance. Results from the Many-Facets Rasch Model are compared with those calculated from the Rasch Rating Scale Model (RRSM) (Spray & Huang, 2000) using two examples of actual job analysis data from diverse professions. In addition, this article proposes a solution for establishing the origin of the percentage scale when transferring the task importance weights from a logit unit into percentage weights. Although the resulting test specifications from the two compared methods are not radically different, a case is made that the use of the Many-Facets Rasch Model with a zero point based on the frequency rating scale provides a more justifiable basis for combining multiple rating scales and transforming task survey data. In addition, this study found that the Many-Facets Rasch Rating Model can better accommodate missing data than the RRSM method in situations in which respondents only rate subsets of the multiple scales and not all of the scales for the tasks being surveyed. [ABSTRACT FROM PUBLISHER]

In this article we introduce the problem of computer software reliability and discuss a probabilistic model for describing the failure of software. We suggest a procedure for estimating the parameters of the model and propose a stopping rule for debugging the software. We apply our procedures to some published data on software failures. [ABSTRACT FROM AUTHOR]