Norm Convergence Rate for Multivariate Quadratic Polynomials of Wigner Matrices

We study Hermitian non-commutative quadratic polynomials of multiple independent Wigner matrices. We prove that, with the exception of some specific reducible cases, the limiting spectral density of the polynomials always has a square root growth at its edges and prove an optimal local law around these edges. Combining these two results, we establish that, as the dimension $N$ of the matrices grows to infinity, the operator norm of such polynomials $q$ converges to a deterministic limit with a rate of convergence of $N^{-2/3+o(1)}$. Here, the exponent in the rate of convergence is optimal. For the specific reducible cases, we also provide a classification of all possible edge behaviours.Comment: 38 page

Alienation and Digital Labour—A Depth-Hermeneutic Inquiry into Online Commodification and the Unconscious

At the core of this paper is a psychosocial inquiry into the Marxist concept of alienation and its applications to the field of digital labour. Following a brief review of different theoretical works on alienation, it looks into its recent conceptualisations and applications to the study of online social networking sites. Finally, the authors offer suggestions on how to extend and render more complex these recent approaches through in-depth analyses of Facebook posts that exemplify how alienation is experienced, articulated, and expressed online. For this perspective, the article draws on Rahel Jaeggi’s (2005) reassessment of alienation, as well as the depth-hermeneutic method of “scenic understanding” developed by Alfred Lorenzer (e.g. 1970; 1986)

Automated Change Rule Inference for Distance-Based API Misuse Detection

Developers build on Application Programming Interfaces (APIs) to reuse existing functionalities of code libraries. Despite the benefits of reusing established libraries (e.g., time savings, high quality), developers may diverge from the API's intended usage; potentially causing bugs or, more specifically, API misuses. Recent research focuses on developing techniques to automatically detect API misuses, but many suffer from a high false-positive rate. In this article, we improve on this situation by proposing ChaRLI (Change RuLe Inference), a technique for automatically inferring change rules from developers' fixes of API misuses based on API Usage Graphs (AUGs). By subsequently applying graph-distance algorithms, we use change rules to discriminate API misuses from correct usages. This allows developers to reuse others' fixes of an API misuse at other code locations in the same or another project. We evaluated the ability of change rules to detect API misuses based on three datasets and found that the best mean relative precision (i.e., for testable usages) ranges from 77.1 % to 96.1 % while the mean recall ranges from 0.007 % to 17.7 % for individual change rules. These results underpin that ChaRLI and our misuse detection are helpful complements to existing API misuse detectors

How do Microservices Evolve?:An Empirical Analysis of Changes in Open-Source Microservice Repositories

Context.Microservice architectures are an emergent service-oriented paradigm widely used in industry to develop and deploy scalable software systems. The underlying idea is to design highly independent services that implement small units of functionality and can interact with each other through lightweight interfaces.Objective.Even though microservices are often used with success, their design and maintenance pose novel challenges to software engineers. In particular, it is questionable whether the intended independence of microservices can actually be achieved in practice.Method.So, it is important to understand how and why microservices evolve during a system’s life-cycle, for instance, to scope refactorings and improvements of a system’s architecture or to develop supporting tools. To provide insights into how microservices evolve, we report a large-scale empirical study on the (co-)evolution of microservices in 11 open-source systems, involving quantitative and qualitative analyses of 7,319 commits.Findings.Our quantitative results show that there are recurring patterns of (co-)evolution across all systems, for instance, “shotgun surgery” commits and microservices that are largely independent, evolve in tuples, or are evolved in almost all changes. We refine our results by analyzing service-evolving commits qualitatively to explore the (in-)dependence of microservices and the causes for their specific evolution.Conclusion.The contributions in this article provide an understanding for practitioners and researchers on how microservices evolve in what way, and how microservice-based systems may be improved

SmartRain – Aufbau eines Bürgermessnetzes zur Bestimmung und Analyse lokaler Niederschlagsverteilungen

Das Projekt SmartRain (https://smart-rain.de/) widmet sich dem Aufbau eines bürgerschaftlichen Messnetzes zur Bestimmung von Niederschlagsverteilungen in der Landeshauptstadt Dresden. Es wird dargelegt, welchen Wert eine smarte Datenerhebung im Bereich der Umweltsensorik haben kann, aber auch, mit welchen Herausforderungen bei der organisatorischen Umsetzung eines solchen Projektes gerechnet werden muss