@unpublished{RamsauerHuberSchwarzetal., author = {Ramsauer, Ralf and Huber, Stefan and Schwarz, Konrad and Kiszka, Jan and Mauerer, Wolfgang}, title = {Static Hardware Partitioning on RISC-V - Shortcomings, Limitations, and Prospects}, doi = {10.48550/arXiv.2208.02703}, abstract = {On embedded processors that are increasingly equipped with multiple CPU cores, static hardware partitioning is an established means of consolidating and isolating workloads onto single chips. This architectural pattern is suitable for mixed-criticality workloads that need to satisfy both, real-time and safety requirements, given suitable hardware properties. In this work, we focus on exploiting contemporary virtualisation mechanisms to achieve freedom from interference respectively isolation between workloads. Possibilities to achieve temporal and spatial isolation-while maintaining real-time capabilities-include statically partitioning resources, avoiding the sharing of devices, and ascertaining zero interventions of superordinate control structures. This eliminates overhead due to hardware partitioning, but implies certain hardware capabilities that are not yet fully implemented in contemporary standard systems. To address such hardware limitations, the customisable and configurable RISC-V instruction set architecture offers the possibility of swift, unrestricted modifications. We present findings on the current RISC-V specification and its implementations that necessitate interventions of superordinate control structures. We identify numerous issues adverse to implementing our goal of achieving zero interventions respectively zero overhead: On the design level, and especially with regards to handling interrupts. Based on micro-benchmark measurements, we discuss the implications of our findings, and argue how they can provide a basis for future extensions and improvements of the RISC-V architecture.}, language = {en} } @unpublished{OberthuerMauerer, author = {Oberth{\"u}r, S. and Mauerer, Wolfgang}, title = {Sicherheit von Android-Systemen}, language = {de} } @inproceedings{Mauerer, author = {Mauerer, Wolfgang}, title = {Supershrink Linux - and beyond}, series = {Embedded Linux Conference Europe (Dublin), 2015}, booktitle = {Embedded Linux Conference Europe (Dublin), 2015}, language = {en} } @inproceedings{ScherzingerMauererKondylakis, author = {Scherzinger, Stefanie and Mauerer, Wolfgang and Kondylakis, Haridimos}, title = {DeBinelle: Semantic Patches for Coupled Database-Application Evolution}, series = {2021 IEEE 37th International Conference on Data Engineering (ICDE 2021): 19-22 April 2021, Chania, Greece}, booktitle = {2021 IEEE 37th International Conference on Data Engineering (ICDE 2021): 19-22 April 2021, Chania, Greece}, editor = {Ailamaki, Anastasia}, publisher = {IEEE}, address = {Piscataway, NJ}, isbn = {978-1-7281-9184-3}, doi = {10.1109/ICDE51399.2021.00307}, pages = {2697 -- 2700}, abstract = {Databases are at the core of virtually any software product. Changes to database schemas cannot be made in isolation, as they are intricately coupled with application code. Such couplings enforce collateral evolution, which is a recognised, important research problem. In this demonstration, we show a new dimension to this problem, in software that supports alternative database backends: vendor-specific SQL dialects necessitate a simultaneous evolution of both, database schema and program code, for all supported DB variants. These near-same changes impose substantial manual effort for software developers. We introduce DeBinelle, a novel framework and domain-specific language for semantic patches that abstracts DB-variant schema changes and coupled program code into a single, unified representation. DeBinelle further offers a novel alternative to manually evolving coupled schemas and code. DeBinelle considerably extends established, seminal results in software engineering research, supporting several programming languages, and the many dialects of SQL. It effectively eliminates the need to perform vendor-specific changes, replacing them with intuitive semantic patches. Our demo of DeBinelle is based on real-world use cases from reference systems for schema evolution.}, language = {en} } @inproceedings{FruthScherzingerMauereretal., author = {Fruth, Michael and Scherzinger, Stefanie and Mauerer, Wolfgang and Ramsauer, Ralf}, title = {Tell-Tale Tail Latencies: Pitfalls and Perils in Database Benchmarking}, series = {Performance evaluation and benchmarking, 13th TPC Technology Conference (TPCTC 2021): Copenhagen, Denmark, August 20, 2021, Revised Selected Papers}, booktitle = {Performance evaluation and benchmarking, 13th TPC Technology Conference (TPCTC 2021): Copenhagen, Denmark, August 20, 2021, Revised Selected Papers}, editor = {Nambiar, Raghunath and Poess, Meikel}, publisher = {Springer}, address = {Cham, Switzerland}, isbn = {9783030944377}, doi = {10.1007/978-3-030-94437-7_8}, pages = {119 -- 134}, abstract = {The performance of database systems is usually characterised by their average-case (i.e., throughput) behaviour in standardised or de-facto standard benchmarks like TPC-X or YCSB. While tails of the latency (i.e., response time) distribution receive considerably less attention, they have been identified as a threat to the overall system performance: In large-scale systems, even a fraction of requests delayed can build up into delays perceivable by end users. To eradicate large tail latencies from database systems, the ability to faithfully record them, and likewise pinpoint them to the root causes, is imminently required. In this paper, we address the challenge of measuring tail latencies using standard benchmarks, and identify subtle perils and pitfalls. In particular, we demonstrate how Java-based benchmarking approaches can substantially distort tail latency observations, and discuss how the discovery of such problems is inhibited by the common focus on throughput performance. We make a case for purposefully re-designing database benchmarking harnesses based on these observations to arrive at faithful characterisations of database performance from multiple important angles.}, language = {en} } @inproceedings{SaxFeldZielinskietal., author = {Sax, Irmi and Feld, Sebastian and Zielinski, Sebastian and Gabor, Thomas and Linnhoff-Popien, Claudia and Mauerer, Wolfgang}, title = {Approximate approximation on a quantum annealer}, series = {Proceedings of the 17th ACM International Conference on Computing Frontiers (CF '20): Catania Sicily Italy 11.05.2020 -13.05.2020}, booktitle = {Proceedings of the 17th ACM International Conference on Computing Frontiers (CF '20): Catania Sicily Italy 11.05.2020 -13.05.2020}, editor = {Palesi, Maurizio}, publisher = {Association for Computing Machinery}, address = {New York, NY, United States}, isbn = {9781450379564}, doi = {10.1145/3387902.3392635}, pages = {108 -- 117}, abstract = {Many problems of industrial interest are NP-complete, and quickly exhaust resources of computational devices with increasing input sizes. Quantum annealers (QA) are physical devices that aim at this class of problems by exploiting quantum mechanical properties of nature. However, they compete with efficient heuristics and probabilistic or randomised algorithms on classical machines that allow for finding approximate solutions to large NP-complete problems. While first implementations of QA have become commercially available, their practical benefits are far from fully explored. To the best of our knowledge, approximation techniques have not yet received substantial attention. In this paper, we explore how problems' approximate versions of varying degree can be systematically constructed for quantum annealer programs, and how this influences result quality or the handling of larger problem instances on given set of qubits. We illustrate various approximation techniques on both, simulations and real QA hardware, on different seminal problems, and interpret the results to contribute towards a better understanding of the real-world power and limitations of current-state and future quantum computing.}, language = {en} } @inproceedings{MauererScherzinger, author = {Mauerer, Wolfgang and Scherzinger, Stefanie}, title = {1-2-3 Reproducibility for Quantum Software Experiments}, series = {2022 IEEE International Conference on Software Analysis, Evolution and Reengineering (SANER), Honolulu, HI, USA, 15-18 March 2022}, booktitle = {2022 IEEE International Conference on Software Analysis, Evolution and Reengineering (SANER), Honolulu, HI, USA, 15-18 March 2022}, publisher = {IEEE}, doi = {10.1109/SANER53432.2022.00148}, pages = {1247 -- 1248}, abstract = {Various fields of science face a reproducibility crisis. For quantum software engineering as an emerging field, it is therefore imminent to focus on proper reproducibility engineering from the start. Yet the provision of reproduction packages is almost universally lacking. Actionable advice on how to build such packages is rare, particularly unfortunate in a field with many contributions from researchers with backgrounds outside computer science. In this article, we argue how to rectify this deficiency by proposing a 1-2-3~approach to reproducibility engineering for quantum software experiments: Using a meta-generation mechanism, we generate DOI-safe, long-term functioning and dependency-free reproduction packages. They are designed to satisfy the requirements of professional and learned societies solely on the basis of project-specific research artefacts (source code, measurement and configuration data), and require little temporal investment by researchers. Our scheme ascertains long-term traceability even when the quantum processor itself is no longer accessible. By drastically lowering the technical bar, we foster the proliferation of reproduction packages in quantum software experiments and ease the inclusion of non-CS researchers entering the field.}, language = {en} } @inproceedings{BrainingerMauererScherzinger, author = {Braininger, Dimitri and Mauerer, Wolfgang and Scherzinger, Stefanie}, title = {Replicability and Reproducibility of a Schema Evolution Study in Embedded Databases}, series = {Advances in conceptual modeling: ER 2020 Workshops CMAI, CMLS, CMOMM4FAIR, CoMoNoS, EmpER, Vienna, Austria, November 3-6, 2020, Proceedings}, volume = {12584}, booktitle = {Advances in conceptual modeling: ER 2020 Workshops CMAI, CMLS, CMOMM4FAIR, CoMoNoS, EmpER, Vienna, Austria, November 3-6, 2020, Proceedings}, editor = {Grossmann, Georg and Ram, Sudha}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-65846-5}, doi = {10.1007/978-3-030-65847-2_19}, pages = {210 -- 219}, abstract = {Ascertaining the feasibility of independent falsification or repetition of published results is vital to the scientific process, and replication or reproduction experiments are routinely performed in many disciplines. Unfortunately, such studies are only scarcely available in database research, with few papers dedicated to re-evaluating published results. In this paper, we conduct a case study on replicating and reproducing a study on schema evolution in embedded databases. We can exactly repeat the outcome for one out of four database applications studied, and come close in two further cases. By reporting results, efforts, and obstacles encountered, we hope to increase appreciation for the substantial efforts required to ensure reproducibility. By discussing minutiae details required to ascertain reproducible work, we argue that such important, but often ignored aspects of scientific work should receive more credit in the evaluation of future research.}, language = {en} } @inproceedings{KruegerMauerer, author = {Kr{\"u}ger, Tom and Mauerer, Wolfgang}, title = {Quantum Annealing-Based Software Components}, series = {Proceedings of the IEEE/ACM 42nd International Conference on Software Engineering Workshops (ICSE'20): Seoul Republic of Korea 27.06.2020 - 19.07.2020}, booktitle = {Proceedings of the IEEE/ACM 42nd International Conference on Software Engineering Workshops (ICSE'20): Seoul Republic of Korea 27.06.2020 - 19.07.2020}, publisher = {Association for Computing Machinery}, address = {New York, NY}, isbn = {9781450379632}, doi = {10.1145/3387940.3391472}, pages = {445 -- 450}, abstract = {Quantum computers have the potential of solving problems more efficiently than classical computers. While first commercial prototypes have become available, the performance of such machines in practical application is still subject to exploration. Quantum computers will not entirely replace classical machines, but serve as accelerators for specific problems. This necessitates integrating quantum computational primitives into existing applications. In this paper, we perform a case study on how to augment existing software with quantum computational primitives for the Boolean satisfiability problem (SAT) implemented using a quantum annealer (QA). We discuss relevant quality measures for quantum components, and show that mathematically equivalent, but structurally different ways of transforming SAT to a QA can lead to substantial differences regarding these qualities. We argue that engineers need to be aware that (and which) details, although they may be less relevant in traditional software engineering, require considerable attention in quantum computing.}, language = {en} } @inproceedings{GaborZielinskiFeldetal., author = {Gabor, Thomas and Zielinski, Sebastian and Feld, Sebastian and Roch, Christoph and Seidel, Christian and Neukart, Florian and Galter, Isabella and Mauerer, Wolfgang and Linnhoff-Popien, Claudia}, title = {Assessing Solution Quality of 3SAT on a Quantum Annealing Platform}, series = {Quantum Technology and Optimization Problems : First International Workshop, QTOP 2019, Munich, Germany, March 18, 2019, Proceedings}, volume = {11413}, booktitle = {Quantum Technology and Optimization Problems : First International Workshop, QTOP 2019, Munich, Germany, March 18, 2019, Proceedings}, editor = {Feld, Sebastian and Linnhoff-Popien, Claudia}, publisher = {Springer International Publishing}, address = {Cham}, isbn = {978-3-030-14081-6}, doi = {10.1007/978-3-030-14082-3_3}, pages = {23 -- 35}, language = {en} } @article{MauererScherzinger, author = {Mauerer, Wolfgang and Scherzinger, Stefanie}, title = {Digitale Forschungswerkzeuge : Nachhaltigkeit f{\"u}r Software und Daten}, series = {Forschung \& Lehre (Forschung und Lehre)}, volume = {28}, journal = {Forschung \& Lehre (Forschung und Lehre)}, number = {10}, publisher = {Zentrum f{\"u}r Wissenschaftsmanagement e.V. (ZWM)
}, organization = {Deutscher Hochschullehrerverband}, pages = {816 -- 817}, abstract = {Die wissenschaftliche Reproduktionskrise hat den Blick auf digitale Forschungswerkzeuge intensiviert. Auch wenn der Mehraufwand f{\"u}r Reproduzierbarkeit und Zug{\"a}nglichkeit zunehmend anerkannt wird, existieren noch Defizite in der Umsetzung, wenn es darum geht, die Datenbasis und Forschungswerkzeuge verf{\"u}gbar zu machen}, language = {de} } @article{BayerstadlerBecquinBinderetal., author = {Bayerstadler, Andreas and Becquin, Guillaume and Binder, Julia and Botter, Thierry and Ehm, Hans and Ehmer, Thomas and Erdmann, Marvin and Gaus, Norbert and Harbach, Philipp and Hess, Maximilian and Klepsch, Johannes and Leib, Martin and Luber, Sebastian and Luckow, Andre and Mansky, Maximilian and Mauerer, Wolfgang and Neukart, Florian and Niedermeier, Christoph and Palackal, Lilly and Pfeiffer, Ruben and Polenz, Carsten and Sepulveda, Johanna and Sievers, Tammo and Standen, Brian and Streif, Michael and Strohm, Thomas and Utschig-Utschig, Clemens and Volz, Daniel and Weiss, Horst and Winter, Fabian}, title = {Industry quantum computing applications}, series = {EPJ Quantum Technology}, volume = {8}, journal = {EPJ Quantum Technology}, publisher = {Springer}, organization = {Springer}, doi = {10.1140/epjqt/s40507-021-00114-x}, pages = {1 -- 17}, abstract = {Quantum computing promises to overcome computational limitations with better and faster solutions for optimization, simulation, and machine learning problems. Europe and Germany are in the process of successfully establishing research and funding programs with the objective to dvance the technology's ecosystem and industrialization, thereby ensuring digital sovereignty, security, and competitiveness. Such an ecosystem comprises hardware/software solution providers, system integrators, and users from research institutions, start-ups, and industry. The vision of the Quantum Technology and Application Consortium (QUTAC) is to establish and advance the quantum computing ecosystem, supporting the ambitious goals of the German government and various research programs. QUTAC is comprised of ten members representing different industries, in particular automotive manufacturing, chemical and pharmaceutical production, insurance, and technology. In this paper, we survey the current state of quantum computing in these sectors as well as the aerospace industry and identify the contributions of QUTAC to the ecosystem. We propose an application-centric approach for the industrialization of the technology based on proven business impact. This paper identifies 24 different use cases. By formalizing high-value use cases into well-described reference problems and benchmarks, we will guide technological progress and eventually commercialization. Our results will be beneficial to all ecosystem participants, including suppliers, system integrators, software developers, users, policymakers, funding program managers, and investors.}, language = {en} } @article{GabrielWittmannSychetal., author = {Gabriel, Christian and Wittmann, Christoffer and Sych, Denis and Dong, Ruifang and Mauerer, Wolfgang and Andersen, Ulrik L. and Marquardt, Christoph and Leuchs, Gerd}, title = {A generator for unique quantum random numbers based on vacuum states}, series = {Nature Photonics}, volume = {4}, journal = {Nature Photonics}, number = {10}, publisher = {Springer}, organization = {Springer}, doi = {10.1038/nphoton.2010.197}, pages = {711 -- 715}, abstract = {Random numbers are a valuable component in diverse applications that range from simulations over gambling to cryptography. The quest for true randomness in these applications has engendered a large variety of different proposals for producing random numbers based on the foundational unpredictability of quantum mechanics4,5,6,7,8,9,10,11. However, most approaches do not consider that a potential adversary could have knowledge about the generated numbers, so the numbers are not verifiably random and unique12,13,14,15. Here we present a simple experimental setup based on homodyne measurements that uses the purity of a continuous-variable quantum vacuum state to generate unique random numbers. We use the intrinsic randomness in measuring the quadratures of a mode in the lowest energy vacuum state, which cannot be correlated to any other state. The simplicity of our source, combined with its verifiably unique randomness, are important attributes for achieving high-reliability, high-speed and low-cost quantum random number generators.}, language = {en} } @article{ColdenstrodtRongeLundeenPregnelletal., author = {Coldenstrodt-Ronge, Hendrik B. and Lundeen, Jeff S. and Pregnell, Kenny L. and Feito, Alvaro and Smith, Brian J. and Mauerer, Wolfgang and Silberhorn, Christine and Eisert, Jens and Plenio, Martin B. and Walmsley, Ian A.}, title = {A proposed testbed for detector tomography}, series = {Journal of Modern Optics}, volume = {56}, journal = {Journal of Modern Optics}, number = {2-3}, publisher = {Taylor\&Francis}, doi = {10.1080/09500340802304929}, pages = {432 -- 441}, abstract = {Measurement is the only part of a general quantum system that has yet to be characterised experimentally in a complete manner. Detector tomography provides a procedure for doing just this; an arbitrary measurement device can be fully characterised, and thus calibrated, in a systematic way without access to its components or its design. The result is a reconstructed POVM containing the measurement operators associated with each measurement outcome. We consider two detectors, a single-photon detector and a photon-number counter, and propose an easily realised experimental apparatus to perform detector tomography on them. We also present a method of visualising the resulting measurement operators.}, language = {en} } @article{MauererAvenhausHelwigetal., author = {Mauerer, Wolfgang and Avenhaus, Malte and Helwig, Wolfram and Silberhorn, Christine}, title = {How colors influence numbers: Photon statistics of parametric down-conversion}, series = {Physical Review A (Phys. Rev. A)}, volume = {80}, journal = {Physical Review A (Phys. Rev. A)}, number = {5}, publisher = {American Physical Society}, doi = {10.1103/physreva.80.053815}, abstract = {Parametric down-conversion (PDC) is a technique of ubiquitous experimental significance in the production of nonclassical, photon-number-correlated twin beams. Standard theory of PDC as a two-mode squeezing process predicts and homodyne measurements observe a thermal photon number distribution per beam. Recent experiments have obtained conflicting distributions. In this article, we explain the observation by an a priori theoretical model solely based on directly accessible physical quantities. We compare our predictions with experimental data and find excellent agreement.}, language = {en} } @article{MauererSawallischHillieretal., author = {Mauerer, Wolfgang and Sawallisch, J. and Hillier, G. and Oberth{\"u}r, S. and H{\"o}nick, S.}, title = {Real-Time Android: Achieving determinism and ease of use}, series = {Embedded Wold Conference; Nuremberg, Germany, February 25, 2014 - February 27, 2014}, journal = {Embedded Wold Conference; Nuremberg, Germany, February 25, 2014 - February 27, 2014}, pages = {1 -- 7}, language = {en} } @article{RohdeMauererSilberhorn, author = {Rohde, Peter P. and Mauerer, Wolfgang and Silberhorn, Christine}, title = {Spectral structure and decompositions of optical states, and their applications}, series = {New Journal of Physics}, volume = {9}, journal = {New Journal of Physics}, number = {4}, publisher = {IOP Publishing}, doi = {10.1088/1367-2630/9/4/091}, pages = {91}, abstract = {We discuss the spectral structure and decomposition of multi-photon states. Ordinarily 'multi-photon states' and 'Fock states' are regarded as synonymous. However, when the spectral degrees of freedom are included this is not the case, and the class of 'multi-photon' states is much broader than the class of 'Fock' states. We discuss the criteria for a state to be considered a Fock state. We then address the decomposition of general multi-photon states into bases of orthogonal eigenmodes, building on existing multi-mode theory, and introduce an occupation number representation that provides an elegant description of such states. This representation allows us to work in bases imposed by experimental constraints, simplifying calculations in many situations. Finally we apply this technique to several example situations, which are highly relevant for state of the art experiments. These include Hong-Ou-Mandel interference, spectral filtering, finite bandwidth photo-detection, homodyne detection and the conditional preparation of Schr{\"o}dinger kitten and Fock states. Our techniques allow for very simple descriptions of each of these examples.}, language = {en} } @article{HelwigMauererSilberhorn, author = {Helwig, Wolfram and Mauerer, Wolfgang and Silberhorn, Christine}, title = {Multimode states in decoy-based quantum-key-distribution protocols}, series = {Physical Review A}, volume = {80}, journal = {Physical Review A}, number = {5}, publisher = {American Physical Society}, doi = {10.1103/physreva.80.052326}, abstract = {Every security analysis of quantum-key distribution (QKD) relies on a faithful modeling of the employed quantum states. Many photon sources, such as for instance a parametric down-conversion (PDC) source, require a multimode description but are usually only considered in a single-mode representation. In general, the important claim in decoy-based QKD protocols for indistinguishability between signal and decoy states does not hold for all sources. We derive bounds on the single-photon transmission probability and error rate for multimode states and apply these bounds to the output state of a PDC source. We observe two opposing effects on the secure key rate. First, the multimode structure of the state gives rise to a new attack that decreases the key rate. Second, more contributing modes change the photon number distribution from a thermal toward a Poissonian distribution, which increases the key rate.}, language = {en} } @article{MauererHelwigSilberhorn, author = {Mauerer, Wolfgang and Helwig, Wolfram and Silberhorn, Christine}, title = {Recent developments in quantum key distribution: Theory and practice}, series = {Annalen der Physik}, volume = {17}, journal = {Annalen der Physik}, number = {2-3}, publisher = {Wiley}, doi = {10.1002/andp.200710284}, pages = {158 -- 175}, abstract = {Quantum key distribution is among the foremost applications of quantum mechanics, both in terms of fundamental physics and as a technology on the brink of commercial deployment. Starting from principal schemes and initial proofs of unconditional security for perfect systems, much effort has gone into providing secure schemes which can cope with numerous experimental imperfections unavoidable in real world implementations. In this paper, we provide a comparison of various schemes and protocols. We analyse their efficiency and performance when implemented with imperfect physical components. We consider how experimental faults are accounted for using effective parameters. We compare various recent protocols and provide guidelines as to which components propose best advances when being improved.}, language = {en} } @article{AvenhausColdenstrodtRongeLaihoetal., author = {Avenhaus, Malte and Coldenstrodt-Ronge, Hendrik B. and Laiho, K. and Mauerer, Wolfgang and Walmsley, I. A. and Silberhorn, Christine}, title = {Photon Number Statistics of Multimode Parametric Down-Conversion}, series = {Physical Review Letters}, volume = {101}, journal = {Physical Review Letters}, number = {5}, publisher = {American Physical Society}, doi = {10.1103/physrevlett.101.053601}, abstract = {We experimentally analyze the complete photon number statistics of parametric down-conversion and ascertain the influence of multimode effects. Our results clearly reveal a difference between single-mode theoretical description and the measured distributions. Further investigations assure the applicability of loss-tolerant photon number reconstruction and prove strict photon number correlation between signal and idler modes.}, language = {en} } @article{MauererSilberhorn, author = {Mauerer, Wolfgang and Silberhorn, Christine}, title = {Quantum key distribution with passive decoy state selection}, series = {Physical Review A}, volume = {75}, journal = {Physical Review A}, number = {5}, publisher = {American Physical Society}, doi = {10.1103/physreva.75.050305}, abstract = {We propose a quantum key distribution scheme which closely matches the performance of a perfect single photon source. It nearly attains the physical upper bound in terms of key generation rate and maximally achievable distance. Our scheme relies on a practical setup based on a parametric downconversion source and present day, nonideal photon-number detection. Arbitrary experimental imperfections which lead to bit errors are included. We select decoy states by classical postprocessing. This allows one to improve the effective signal statistics and achievable distance.}, language = {en} } @book{Mauerer, author = {Mauerer, Wolfgang}, title = {Professional Linux kernel architecture}, series = {Wrox professional guides}, journal = {Wrox professional guides}, publisher = {Wiley}, address = {Indianapolis}, isbn = {9780470343432}, abstract = {Find an introduction to the architecture, concepts and algorithms of the Linux kernel in Professional Linux Kernel Architecture, a guide to the kernel sources and large number of connections among subsystems. Find an introduction to the relevant structures and functions exported by the kernel to userland, understand the theoretical and conceptual aspects of the Linux kernel and Unix derivatives, and gain a deeper understanding of the kernel. Learn how to reduce the vast amount of information contained in the kernel sources and obtain the skills necessary to understand the kernel sources.}, language = {en} } @article{Mauerer, author = {Mauerer, Wolfgang}, title = {Datenvisualisierung mit Ggplot2}, series = {Linux-Magazin}, journal = {Linux-Magazin}, number = {3}, publisher = {Linux New Media AG}, abstract = {Wer seine Daten mit ansehnlichen und informativen Graphen veranschaulichen m{\"o}chte, braucht meist viel Geduld. Die R-Erweiterung Ggplot2 bringt System in die Grafik, dr{\"u}ckt sich in knappem Quellcode aus und bl{\"a}st frischen Wind in den Alltag der Datenvisualisierung.}, language = {en} }