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Aristotle vs. Ringelmann was a discussion between two distinct research teams from the ETH Z\"urich who argued whether the productivity of Open Source software projects scales sublinear or superlinear with regard to its team size. This discussion evolved around two publications, which apparently used similar techniques by sampling projects on GitHub and running regression analyses to answer the question about superlinearity. Despite the similarity in their research methods, one team around Ingo Scholtes reached the conclusion that projects scale sublinear, while the other team around Didier Sornette ascertained a superlinear relationship between team size and productivity. In subsequent publications, the two authors argue that the opposite conclusions may be attributed to differences in project populations, since 81.7% of Sornette's projects have less than 50 contributors. Scholtes, on the other hand, sampled specifically projects with more than 50 contributors. This publication compares the research from both authors by replicating their findings, thus allowing for an evaluation of how much project sampling actually accounted for the differences between Scholtes' and Sornette's results. Thereby, the discovery was made that sampling bias only partially explains the discrepancies between the two authors. Further analysis led to the detection of instrumentation biases that drove the regression coefficients in opposite directions. These findings were then consolidated into a quantitative analysis, indicating that instrumentation biases contributed more to the differences between Scholtes' and Sornette's work than the selection bias suggested by both authors., Comment: 10 pages, 12 figures, 4 tables, SBES'24, September 30 - October 04, 2024, Curitiba, PR

This work investigates Artificial Intelligence (AI) systems that detect respiratory insufficiency (RI) by analyzing speech audios, thus treating speech as a RI biomarker. Previous works collected RI data (P1) from COVID-19 patients during the first phase of the pandemic and trained modern AI models, such as CNNs and Transformers, which achieved $96.5\%$ accuracy, showing the feasibility of RI detection via AI. Here, we collect RI patient data (P2) with several causes besides COVID-19, aiming at extending AI-based RI detection. We also collected control data from hospital patients without RI. We show that the considered models, when trained on P1, do not generalize to P2, indicating that COVID-19 RI has features that may not be found in all RI types., Comment: 5 pages, 2 figures, 1 table. Published in Artificial Intelligence in Medicine (AIME) 2023

With the agile approach to managing software development projects comes an increased dependability on well functioning teams, since many of the practices are built on teamwork. The objective of this study was to investigate if, and how, team development from a group psychological perspective is related to some work practices of agile teams. Data were collected from 34 agile teams (200 individuals) from six software development organizations and one university in both Brazil and Sweden using the Group Development Questionnaire (Scale IV) and the Perceptive Agile Measurement (PAM). The result indicates a strong correlation between levels of group maturity and the two agile practices \emph{iterative development} and \emph{retrospectives}. We, therefore, conclude that agile teams at different group development stages adopt parts of team agility differently, thus confirming previous studies but with more data and by investigating concrete and applied agile practices. We thereby add evidence to the hypothesis that an agile implementation and management of agile projects need to be adapted to the group maturity levels of the agile teams.

Research has shown that the maturity of small workgroups from a psychological perspective is intimately connected to team agility. We, therefore, tested if agile team members appreciated group development psychology training. Our results show that the participating teams seem to have a very positive view of group development training and state that they now have a new way of thinking about teamwork and new tools to deal with team-related problems. We, therefore, see huge potential in training agile teams in group development psychology since the positive effects might span over the entire software development organization.

There has been some evidence that agility is connected to the group maturity of software development teams. This study aims at conducting group development psychology training with student teams, participating in a project course at university, and compare their group effectiveness score to their agility usage over time in a longitudinal design. Seven XP student teams were measured twice (43+40), which means 83 data points divided into two groups (an experimental group and one control group). The results showed that the agility measurement was not possible to increase by giving a 1.5-hour of group psychology lecture and discussion over a two-month period. The non-significant result was probably due to the fact that 1.5 hours of training were not enough to change the work methods of these student teams, or, a causal relationship does not exist between the two concepts. A third option could be that the experiential setting of real teams, even at a university, has many more variables not taken into account in this experiment that affect the two concepts. We therefore have no conclusions to draw based on the expected effects. However, we believe these concepts have to be connected since agile software development is based on teamwork to a large extent, but there are probably many more confounding or mediating factors.

In this paper we describe the usefulness of statistical validation techniques for human factors survey research. We need to investigate a diversity of validity aspects when creating metrics in human factors research, and we argue that the statistical tests used in other fields to get support for reliability and construct validity in surveys, should also be applied to human factors research in software engineering more often. We also show briefly how such methods can be applied (Test-Retest, Cronbach's {\alpha}, and Exploratory Factor Analysis).

Scheduling is essentially a decision-making process that enables resource sharing among a number of activities by determining their execution order on the set of available resources. The emergence of distributed systems brought new challenges on scheduling in computer systems, including clusters, grids, and more recently clouds. On the other hand, the plethora of research makes it hard for both newcomers researchers to understand the relationship among different scheduling problems and strategies proposed in the literature, which hampers the identification of new and relevant research avenues. In this paper we introduce a classification of the scheduling problem in distributed systems by presenting a taxonomy that incorporates recent developments, especially those in cloud computing. We review the scheduling literature to corroborate the taxonomy and analyze the interest in different branches of the proposed taxonomy. Finally, we identify relevant future directions in scheduling for distributed systems.

In this paper, we explore the automation of services' compositions. We focus on the service selection problem. In the formulation that we consider, the problem's inputs are constituted by a behavioral composition whose abstract services must be bound to concrete ones. The objective is to find the binding that optimizes the {\it utility} of the composition under some services level agreements. We propose a complete solution. Firstly, we show that the service selection problem can be mapped onto a Constraint Satisfaction Problem (CSP). The benefit of this mapping is that the large know-how in the resolution of the CSP can be used for the service selection problem. Among the existing techniques for solving CSP, we consider the backtracking. Our second contribution is to propose various backtracking-based algorithms for the service selection problem. The proposed variants are inspired by existing heuristics for the CSP. We analyze the runtime gain of our framework over an intuitive resolution based on exhaustive search. Our last contribution is an experimental evaluation in which we demonstrate that there is an effective gain in using backtracking instead of some comparable approaches. The experiments also show that our proposal can be used for finding in real time, optimal solutions on small and medium services' compositions., Comment: 31 pages