TY - CHAP A1 - Schönberger, Manuel A1 - Trummer, Immanuel A1 - Mauerer, Wolfgang T1 - Quantum Optimisation of General Join Trees T2 - Joint Workshops at 49th International Conference on Very Large Data Bases (VLDBW’23) — International Workshop on Quantum Data Science and Management (QDSM’23), August 28 - September 1, 2023, Vancouver, Canada (CEUR Workshop Proceedings) N2 - Recent advances in the manufacture of quantum computers attract much attention over a wide range of fields, as early-stage quantum processing units (QPU) have become accessible. While contemporary quantum machines are very limited in size and capabilities, mature QPUs are speculated to eventually excel at optimisation problems. This makes them an attractive technology for database problems, many of which are based on complex optimisation problems with large solution spaces. Yet, the use of quantum approaches on database problems remains largely unexplored. In this paper, we address the long-standing join ordering problem, one of the most extensively researched database problems. Rather than running arbitrary code, QPUs require specific mathematical problem encodings. An encoding for the join ordering problem was recently proposed, allowing first small-scale queries to be optimised on quantum hardware. However, it is based on a faithful transformation of a mixed integer linear programming (MILP) formulation for JO, and inherits all limitations of the MILP method. Most strikingly, the existing encoding only considers a solution space with left-deep join trees, which tend to yield larger costs than general, bushy join trees. We propose a novel QUBO encoding for the join ordering problem. Rather than transforming existing formulations, we construct a native encoding tailored to quantum systems, which allows us to process general bushy join trees. This makes the full potential of QPUs available for solving join order optimisation problems. Y1 - 2023 UR - https://ceur-ws.org/Vol-3462/QDSM2.pdf SP - 1 EP - 12 PB - RWTH Aachen, Sun SITE Central Europe CY - Aachen ER - TY - CHAP A1 - Uotila, Valter A1 - Groppe, Sven A1 - Gruenwald, Le A1 - Lu, Jiaheng A1 - Mauerer, Wolfgang T1 - Preface QDSM T2 - Joint Workshops at 49th International Conference on Very Large Data Bases (VLDBW’23) — International Workshop on Quantum Data Science and Management (QDSM’23), August 28 - September 1, 2023, Vancouver, Canada (CEUR Workshop Proceedings) N2 - The first international workshop on Quantum Data Science and anagement (QDSM), co-located with VLDB 2023, is centered around addressing the possibilities of quantum computing for data science and data management. Quantum computing is a relatively new and emerging field that is believed to have huge computational potential in the future. In the QDSM workshop, we want to provide a venue for discussing and publishing novel results of applying quantum computing to hard data science and data management problems. These problems include join order optimization, designing efficient quantum feature maps, studying possibilities of solving linear programs with quantum algorithms, and divergent index tuning with quantum machine learning. Besides, we include a short and visionary survey on quantum computing for databases. Theworkshop provides a platform for active discussion on these and related topics. Y1 - 2023 UR - https://ceur-ws.org/Vol-3462/QDSM1.pdf PB - RWTH Aachen, Sun SITE Central Europe CY - Aachen ER - TY - CHAP A1 - Joblin, Mitchell A1 - Apel, Sven A1 - Hunsen, Claus A1 - Mauerer, Wolfgang T1 - Classifying Developers into Core and Peripheral: An Empirical Study on Count and Network Metrics T2 - 2017 IEEE/ACM 39th International Conference on Software Engineering (ICSE), Buenos Aires, Argentina, 20-28 May 2017 N2 - Knowledge about the roles developers play in a software project is crucial to understanding the project's collaborative dynamics. In practice, developers are often classified according to the dichotomy of core and peripheral roles. Typically, count-based operationalizations, which rely on simple counts of individual developer activities (e.g., number of commits), are used for this purpose, but there is concern regarding their validity and ability to elicit meaningful insights. To shed light on this issue, we investigate whether count-based operationalizations of developer roles produce consistent results, and we validate them with respect to developers' perceptions by surveying 166 developers. Improving over the state of the art, we propose a relational perspective on developer roles, using fine-grained developer networks modeling the organizational structure, and by examining developer roles in terms of developers' positions and stability within the developer network. In a study of 10 substantial open-source projects, we found that the primary difference between the count-based and our proposed network-based core-peripheral operationalizations is that the network-based ones agree more with developer perception than count-based ones. Furthermore, we demonstrate that a relational perspective can reveal further meaningful insights, such as that core developers exhibit high positional stability, upper positions in the hierarchy, and high levels of coordination with other core developers, which confirms assumptions of previous work. Y1 - 2017 U6 - https://doi.org/10.1109/icse.2017.23 SP - 164 EP - 174 PB - IEEE ER - TY - CHAP A1 - Joblin, Mitchell A1 - Mauerer, Wolfgang A1 - Apel, Sven A1 - Siegmund, Janet A1 - Riehle, Dirk T1 - From Developer Networks to Verified Communities: A Fine-Grained Approach T2 - 2015 IEEE/ACM 37th IEEE International Conference on Software Engineering, 16-24 May 2015, Florence, Italy N2 - Effective software engineering demands a coordinated effort. Unfortunately, a comprehensive view on developer coordination is rarely available to support software-engineering decisions, despite the significant implications on software quality, software architecture, and developer productivity. We present a fine-grained, verifiable, and fully automated approach to capture a view on developer coordination, based on commit information and source-code structure, mined from version-control systems. We apply methodology from network analysis and machine learning to identify developer communities automatically. Compared to previous work, our approach is fine-grained, and identifies statistically significant communities using order-statistics and a community-verification technique based on graph conductance. To demonstrate the scalability and generality of our approach, we analyze ten open-source projects with complex and active histories, written in various programming languages. By surveying 53 open-source developers from the ten projects, we validate the authenticity of inferred community structure with respect to reality. Our results indicate that developers of open-source projects form statistically significant community structures and this particular view on collaboration largely coincides with developers' perceptions of real-world collaboration. KW - collaboration KW - Computer languages KW - Measurement KW - Open Source Software KW - Software systems KW - Standards Y1 - 2015 SN - 978-1-4799-1934-5 U6 - https://doi.org/10.1109/icse.2015.73 SP - 563 EP - 573 PB - IEEE ER - TY - JOUR A1 - Joblin, Mitchell A1 - Apel, Sven A1 - Mauerer, Wolfgang T1 - Evolutionary trends of developer coordination: a network approach JF - Empirical Software Engineering N2 - Software evolution is a fundamental process that transcends the realm of technical artifacts and permeates the entire organizational structure of a software project. By means of a longitudinal empirical study of 18 large open-source projects, we examine and discuss the evolutionary principles that govern the coordination of developers. By applying a network-analytic approach, we found that the implicit and self-organizing structure of developer coordination is ubiquitously described by non-random organizational principles that defy conventional software-engineering wisdom. In particular, we found that: (a) developers form scale-free networks, in which the majority of coordination requirements arise among an extremely small number of developers, (b) developers tend to accumulate coordination requirements with more and more developers over time, presumably limited by an upper bound, and (c) initially developers are hierarchically arranged, but over time, form a hybrid structure, in which core developers are hierarchically arranged and peripheral developers are not. Our results suggest that the organizational structure of large projects is constrained to evolve towards a state that balances the costs and benefits of developer coordination, and the mechanisms used to achieve this state depend on the project’s scale. KW - Developer coordination KW - Developer networks KW - Software evolution Y1 - 2016 U6 - https://doi.org/10.1007/s10664-016-9478-9 VL - 22 IS - 4 SP - 2050 EP - 2094 PB - Springer ER - TY - JOUR A1 - Joblin, Mitchell A1 - Mauerer, Wolfgang T1 - An Interactive Survey Framework for Validation of Social Network Analysis JF - The R Journal N2 - Abstract Social network analysis is extremely well supported by the R community and is routinely used for studying the relationships between people engaged in collaborative activities. While there has been rapid development of new approaches and metrics in this field, the challenging question of validity (how well insights derived from social networks agree with reality) is often difficult to address. We propose the use of several R packages to generate interactive surveys that are specifically well suited for validating social network analyses. Using our web-based survey application, we were able to validate the results of applying community-detection algorithms to infer the organizational structure of software developers contributing to open-source projects. Y1 - 2016 UR - https://journal.r-project.org/archive/2016/RJ-2016-010/index.html VL - 8 IS - 1 SP - 149 EP - 158 ER - TY - JOUR A1 - Appelhans, Marie-Luise A1 - Kampmann, Matthias A1 - Mottok, Jürgen A1 - Riederer, Michael A1 - Nagl, Klaus A1 - Steffens, Oliver A1 - Dünnweber, Jan A1 - Wildgruber, Markus A1 - Roth, Julius A1 - Stadler, Timo A1 - Palm, Christoph A1 - Weiß, Martin Georg A1 - Rochholz, Sandra A1 - Bierl, Rudolf A1 - Gschossmann, Andreas A1 - Haug, Sonja A1 - Schmidbauer, Simon A1 - Koch, Anna A1 - Westner, Markus A1 - Bary, Benedikt von A1 - Ellermeier, Andreas A1 - Vögele, Daniel A1 - Maiwald, Frederik A1 - Hierl, Stefan A1 - Schlamp, Matthias A1 - Ehrlich, Ingo A1 - Siegl, Marco A1 - Hüntelmann, Sven A1 - Wildfeuer, Matthias A1 - Brückl, Oliver A1 - Sterner, Michael A1 - Hofrichter, Andreas A1 - Eckert, Fabian A1 - Bauer, Franz A1 - Dawoud, Belal A1 - Rabl, Hans-Peter A1 - Gamisch, Bernd A1 - Schmidt, Ottfried A1 - Heberl, Michael A1 - Thema, Martin A1 - Mayer, Ulrike A1 - Eller, Johannes A1 - Sippenauer, Thomas A1 - Adelt, Christian A1 - Haslbeck, Matthias A1 - Vogl, Bettina A1 - Mauerer, Wolfgang A1 - Ramsauer, Ralf A1 - Lohmann, Daniel A1 - Sax, Irmengard A1 - Gabor, Thomas A1 - Feld, Sebastian A1 - Linnhoff-Popien, Claudia A1 - Ławrowski, Robert Damian A1 - Langer, Christoph A1 - Schreiner, Rupert A1 - Sellmair, Josef ED - Baier, Wolfgang T1 - Forschung 2019 BT - Thema: Künstliche Intelligenz N2 - Bericht mit Forschungsprojekten aus verschiedenen Bereichen der OTH Regensburg mit dem Schwerpunktthema "Künstliche Intelligenz" und einem Gespräch zur "Medizin der Zukunft" T3 - Forschungsberichte der OTH Regensburg - 2019 KW - Forschung KW - Forschungsbericht KW - Künstliche Intelligenz Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-7890 SN - 978-3-9818209-7-3 CY - Regensburg ER - TY - CHAP A1 - Franz, Maja A1 - Zurita, Pía A1 - Diefenthaler, Markus A1 - Mauerer, Wolfgang T1 - Co-Design of Quantum Hardware and Algorithms in Nuclear and High Energy Physics T2 - EPJ Web of Conferences N2 - Quantum computing (QC) has emerged as a promising technology, and is believed to have the potential to advance nuclear and high energy physics (NHEP) by harnessing quantum mechanical phenomena to accelerate computations. In this paper, we give a brief overview of the current state of quantum computing by highlighting challenges it poses and opportunities it offers to the NHEP community. Noisy intermediate-scale quantum (NISQ) computers, while limited by imperfections and small scale, may hold promise for near-term quantum advantages when coupled with co-designed quantum algorithms and special-purpose quantum processing units (QPUs). We explore various applications in NHEP, including quantum simulation, event classification, and realtime experiment control, emphasising the potential of variational quantum circuits and related techniques. To identify current interests of the community, we perform an analysis of recent literature in NHEP related to QC. Y1 - 2024 U6 - https://doi.org/10.1051/epjconf/202429512002 VL - 295 PB - EDP Sciences ER - TY - JOUR A1 - Mauerer, Wolfgang A1 - Joblin, Mitchell A1 - Tamburri, Damian A1 - Paradis, Carlos A1 - Kazman, Rick A1 - Apel, Sven T1 - In Search of Socio-Technical Congruence: A Large-Scale Longitudinal Study JF - IEEE Transactions on Software Engineering (TSE) N2 - This paper describes a large-scale empirical study investigating the relevance of socio-technical congruence over key basic software quality metrics, namely, bugs and churn. That is, we explore whether alignment or misalignment of social communication structures and technical dependencies in large software projects influences software quality. To this end, we have defined a quantitative and operational notion of socio-technical congruence, which we call /socio-technical motif congruence/ (STMC). STMC is a measure of the degree to which developers working on the same file or on two related files, need to communicate. As socio-technical congruence is a complex and multi-faceted phenomenon, the interpretability of the results is one of our main concerns, so we have employed a careful mixed-methods statistical analysis. In particular, we provide analyses with similar techniques as employed by seminal work in the field to ensure comparability of our results with the existing body of work. The major result of our study, based on an analysis of 25 large open-source projects, is that STMC is /not/ related to project quality measures---software bugs and churn---in any temporal scenario. That is, we find no statistical relationship between the alignment of developer tasks and developer communications on one hand, and project outcomes on the other hand. We conclude that, wherefore congruence does matter as literature shows, then its measurable effect lies elsewhere. KW - Socio-Technical Congruence KW - Human Factors in Software Engineering; KW - Graph Analysis KW - Empirical Software Engineering KW - Quantitative Software Engineering KW - Mixed-Methods Research KW - Socio-Technical Analysis Y1 - 2022 U6 - https://doi.org/10.1109/TSE.2021.3082074 N1 - Corresponding author: Wolfgang Mauerer VL - 48 IS - 8 SP - 3159 EP - 3184 PB - IEEE ER - TY - CHAP A1 - Gabriel, Christian A1 - Wittmann, Christoffer A1 - Hacker, B. A1 - Mauerer, Wolfgang A1 - Huntington, E. A1 - Sabuncu, M. A1 - Marquardt, Christoph A1 - Leuchs, Gerd T1 - A high-speed secure quantum random number generator based on vacuum states T2 - IEEE/OSA Conference on Lasers and Electro-Optics (CLEO), 06-11 May 2012, San Jose CA USA N2 - A high-speed continuous-variable quantum random bit generator with an expected effective bit generation rate of up to 10 GBit/s is presented. The obtained bit sequences are truly random and unique, i.e. they cannot be known by an adversary. Y1 - 2012 PB - Optical Society of America ER -