TY - INPR A1 - Ramsauer, Ralf A1 - Huber, Stefan A1 - Schwarz, Konrad A1 - Kiszka, Jan A1 - Mauerer, Wolfgang T1 - Static Hardware Partitioning on RISC-V - Shortcomings, Limitations, and Prospects N2 - 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. Y1 - 2022 U6 - https://doi.org/10.48550/arXiv.2208.02703 ER - TY - INPR A1 - Oberthür, S. A1 - Mauerer, Wolfgang T1 - Sicherheit von Android-Systemen Y1 - 2012 ER - TY - CHAP A1 - Mauerer, Wolfgang T1 - Supershrink Linux – and beyond T2 - Embedded Linux Conference Europe (Dublin), 2015 Y1 - ER - TY - CHAP A1 - Scherzinger, Stefanie A1 - Mauerer, Wolfgang A1 - Kondylakis, Haridimos ED - Ailamaki, Anastasia T1 - DeBinelle: Semantic Patches for Coupled Database-Application Evolution T2 - 2021 IEEE 37th International Conference on Data Engineering (ICDE 2021): 19-22 April 2021, Chania, Greece N2 - 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. KW - database management systems KW - databases KW - evolution KW - programming language semantics KW - semantic patches KW - software product lines KW - specification languages KW - SQL Y1 - 2021 SN - 978-1-7281-9184-3 U6 - https://doi.org/10.1109/ICDE51399.2021.00307 SP - 2697 EP - 2700 PB - IEEE CY - Piscataway, NJ ER - TY - CHAP A1 - Fruth, Michael A1 - Scherzinger, Stefanie A1 - Mauerer, Wolfgang A1 - Ramsauer, Ralf ED - Nambiar, Raghunath ED - Poess, Meikel T1 - Tell-Tale Tail Latencies: Pitfalls and Perils in Database Benchmarking T2 - Performance evaluation and benchmarking, 13th TPC Technology Conference (TPCTC 2021): Copenhagen, Denmark, August 20, 2021, Revised Selected Papers N2 - 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. KW - Benchmark harness KW - Database benchmarks KW - Tail latencies Y1 - 2022 SN - 9783030944377 U6 - https://doi.org/10.1007/978-3-030-94437-7_8 SP - 119 EP - 134 PB - Springer CY - Cham, Switzerland ER - TY - CHAP A1 - Sax, Irmi A1 - Feld, Sebastian A1 - Zielinski, Sebastian A1 - Gabor, Thomas A1 - Linnhoff-Popien, Claudia A1 - Mauerer, Wolfgang ED - Palesi, Maurizio T1 - Approximate approximation on a quantum annealer T2 - Proceedings of the 17th ACM International Conference on Computing Frontiers (CF '20): Catania Sicily Italy 11.05.2020 -13.05.2020 N2 - 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. KW - approximation algorithms analysis KW - Approximation, NP-complete problems KW - Quantum Annealin KW - quantum computation KW - Simplifying Qubos Y1 - 2020 SN - 9781450379564 U6 - https://doi.org/10.1145/3387902.3392635 SP - 108 EP - 117 PB - Association for Computing Machinery CY - New York, NY, United States ER - TY - CHAP A1 - Mauerer, Wolfgang A1 - Scherzinger, Stefanie T1 - 1-2-3 Reproducibility for Quantum Software Experiments T2 - 2022 IEEE International Conference on Software Analysis, Evolution and Reengineering (SANER), Honolulu, HI, USA, 15-18 March 2022 N2 - 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. KW - Computer Science KW - Quantum Physics KW - Software Engineering Y1 - 2022 U6 - https://doi.org/10.1109/SANER53432.2022.00148 SP - 1247 EP - 1248 PB - IEEE ER - TY - CHAP A1 - Braininger, Dimitri A1 - Mauerer, Wolfgang A1 - Scherzinger, Stefanie ED - Grossmann, Georg ED - Ram, Sudha T1 - Replicability and Reproducibility of a Schema Evolution Study in Embedded Databases T2 - Advances in conceptual modeling: ER 2020 Workshops CMAI, CMLS, CMOMM4FAIR, CoMoNoS, EmpER, Vienna, Austria, November 3-6, 2020, Proceedings N2 - 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. KW - replicability KW - reproducibility KW - schema evolution Y1 - 2020 SN - 978-3-030-65846-5 U6 - https://doi.org/10.1007/978-3-030-65847-2_19 VL - 12584 SP - 210 EP - 219 PB - Springer CY - Cham ER - TY - CHAP A1 - Krüger, Tom A1 - Mauerer, Wolfgang T1 - Quantum Annealing-Based Software Components T2 - Proceedings of the IEEE/ACM 42nd International Conference on Software Engineering Workshops (ICSE'20): Seoul Republic of Korea 27.06.2020 - 19.07.2020 N2 - 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. KW - Boolean Satisfiability KW - Experimental Performance Analysis KW - Quantum Annealin KW - Quantum computing Y1 - 2020 SN - 9781450379632 U6 - https://doi.org/10.1145/3387940.3391472 SP - 445 EP - 450 PB - Association for Computing Machinery CY - New York, NY ER - TY - CHAP A1 - Gabor, Thomas A1 - Zielinski, Sebastian A1 - Feld, Sebastian A1 - Roch, Christoph A1 - Seidel, Christian A1 - Neukart, Florian A1 - Galter, Isabella A1 - Mauerer, Wolfgang A1 - Linnhoff-Popien, Claudia ED - Feld, Sebastian ED - Linnhoff-Popien, Claudia T1 - Assessing Solution Quality of 3SAT on a Quantum Annealing Platform T2 - Quantum Technology and Optimization Problems : First International Workshop, QTOP 2019, Munich, Germany, March 18, 2019, Proceedings Y1 - 2019 SN - 978-3-030-14081-6 U6 - https://doi.org/10.1007/978-3-030-14082-3_3 VL - 11413 SP - 23 EP - 35 PB - Springer International Publishing CY - Cham ER - TY - JOUR A1 - Mauerer, Wolfgang A1 - Scherzinger, Stefanie T1 - Digitale Forschungswerkzeuge : Nachhaltigkeit für Software und Daten JF - Forschung & Lehre (Forschung und Lehre) N2 - Die wissenschaftliche Reproduktionskrise hat den Blick auf digitale Forschungswerkzeuge intensiviert. Auch wenn der Mehraufwand für Reproduzierbarkeit und Zugänglichkeit zunehmend anerkannt wird, existieren noch Defizite in der Umsetzung, wenn es darum geht, die Datenbasis und Forschungswerkzeuge verfügbar zu machen Y1 - 2021 UR - https://www.wissenschaftsmanagement-online.de/system/files/downloads-wimoarticle/2021-10_WIMO_Digitale_Forschungswerkzeuge_Mauerer_Scherzinger.pdf VL - 28 IS - 10 SP - 816 EP - 817 PB - Zentrum für Wissenschaftsmanagement e.V. (ZWM)
 ER - TY - JOUR A1 - Bayerstadler, Andreas A1 - Becquin, Guillaume A1 - Binder, Julia A1 - Botter, Thierry A1 - Ehm, Hans A1 - Ehmer, Thomas A1 - Erdmann, Marvin A1 - Gaus, Norbert A1 - Harbach, Philipp A1 - Hess, Maximilian A1 - Klepsch, Johannes A1 - Leib, Martin A1 - Luber, Sebastian A1 - Luckow, Andre A1 - Mansky, Maximilian A1 - Mauerer, Wolfgang A1 - Neukart, Florian A1 - Niedermeier, Christoph A1 - Palackal, Lilly A1 - Pfeiffer, Ruben A1 - Polenz, Carsten A1 - Sepulveda, Johanna A1 - Sievers, Tammo A1 - Standen, Brian A1 - Streif, Michael A1 - Strohm, Thomas A1 - Utschig-Utschig, Clemens A1 - Volz, Daniel A1 - Weiss, Horst A1 - Winter, Fabian T1 - Industry quantum computing applications JF - EPJ Quantum Technology N2 - 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. KW - Benchmarks KW - Industry application KW - Quantum computing KW - QUTAC KW - Reference problems Y1 - 2021 U6 - https://doi.org/10.1140/epjqt/s40507-021-00114-x VL - 8 SP - 1 EP - 17 PB - Springer ER - TY - JOUR A1 - Gabriel, Christian A1 - Wittmann, Christoffer A1 - Sych, Denis A1 - Dong, Ruifang A1 - Mauerer, Wolfgang A1 - Andersen, Ulrik L. A1 - Marquardt, Christoph A1 - Leuchs, Gerd T1 - A generator for unique quantum random numbers based on vacuum states JF - Nature Photonics N2 - 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. Y1 - 2010 U6 - https://doi.org/10.1038/nphoton.2010.197 VL - 4 IS - 10 SP - 711 EP - 715 PB - Springer ER - TY - JOUR A1 - Coldenstrodt-Ronge, Hendrik B. A1 - Lundeen, Jeff S. A1 - Pregnell, Kenny L. A1 - Feito, Alvaro A1 - Smith, Brian J. A1 - Mauerer, Wolfgang A1 - Silberhorn, Christine A1 - Eisert, Jens A1 - Plenio, Martin B. A1 - Walmsley, Ian A. T1 - A proposed testbed for detector tomography JF - Journal of Modern Optics N2 - 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. Y1 - 2009 U6 - https://doi.org/10.1080/09500340802304929 VL - 56 IS - 2-3 SP - 432 EP - 441 PB - Taylor&Francis ER - TY - JOUR A1 - Mauerer, Wolfgang A1 - Avenhaus, Malte A1 - Helwig, Wolfram A1 - Silberhorn, Christine T1 - How colors influence numbers: Photon statistics of parametric down-conversion JF - Physical Review A (Phys. Rev. A) N2 - 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. Y1 - 2009 U6 - https://doi.org/10.1103/physreva.80.053815 VL - 80 IS - 5 PB - American Physical Society ER - TY - JOUR A1 - Mauerer, Wolfgang A1 - Sawallisch, J. A1 - Hillier, G. A1 - Oberthür, S. A1 - Hönick, S. T1 - Real-Time Android: Achieving determinism and ease of use JF - Embedded Wold Conference; Nuremberg, Germany, February 25, 2014 - February 27, 2014 Y1 - 2014 UR - http://www.linuxtag.org/2012/fileadmin/www.linuxtag.org/slides/Gernot%20Hillier%20+%20Wolfgang%20Mauerer%20+%20Jan%20Sawallisch%20-%20Android_%20real-time%20for%20the%20rest%20of%20us.p416.pdf SP - 1 EP - 7 ER - TY - JOUR A1 - Rohde, Peter P. A1 - Mauerer, Wolfgang A1 - Silberhorn, Christine T1 - Spectral structure and decompositions of optical states, and their applications JF - New Journal of Physics N2 - 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 Schrödinger kitten and Fock states. Our techniques allow for very simple descriptions of each of these examples. Y1 - 2007 U6 - https://doi.org/10.1088/1367-2630/9/4/091 VL - 9 IS - 4 PB - IOP Publishing ER - TY - JOUR A1 - Helwig, Wolfram A1 - Mauerer, Wolfgang A1 - Silberhorn, Christine T1 - Multimode states in decoy-based quantum-key-distribution protocols JF - Physical Review A N2 - 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. Y1 - 2009 U6 - https://doi.org/10.1103/physreva.80.052326 VL - 80 IS - 5 PB - American Physical Society ER - TY - JOUR A1 - Mauerer, Wolfgang A1 - Helwig, Wolfram A1 - Silberhorn, Christine T1 - Recent developments in quantum key distribution: Theory and practice JF - Annalen der Physik N2 - 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. KW - experimental imperfections KW - quantum communication KW - Quantum cryptography Y1 - 2008 U6 - https://doi.org/10.1002/andp.200710284 VL - 17 IS - 2-3 SP - 158 EP - 175 PB - Wiley ER - TY - JOUR A1 - Avenhaus, Malte A1 - Coldenstrodt-Ronge, Hendrik B. A1 - Laiho, K. A1 - Mauerer, Wolfgang A1 - Walmsley, I. A. A1 - Silberhorn, Christine T1 - Photon Number Statistics of Multimode Parametric Down-Conversion JF - Physical Review Letters N2 - 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. Y1 - 2008 U6 - https://doi.org/10.1103/physrevlett.101.053601 VL - 101 IS - 5 PB - American Physical Society ER - TY - JOUR A1 - Mauerer, Wolfgang A1 - Silberhorn, Christine T1 - Quantum key distribution with passive decoy state selection JF - Physical Review A N2 - 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. Y1 - 2007 U6 - https://doi.org/10.1103/physreva.75.050305 VL - 75 IS - 5 PB - American Physical Society ER - TY - BOOK A1 - Mauerer, Wolfgang T1 - Professional Linux kernel architecture T3 - Wrox professional guides N2 - 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. KW - Architektur KW - Kernel KW - Linux Y1 - 2008 SN - 9780470343432 PB - Wiley CY - Indianapolis ER - TY - JOUR A1 - Mauerer, Wolfgang T1 - Datenvisualisierung mit Ggplot2 JF - Linux-Magazin N2 - Wer seine Daten mit ansehnlichen und informativen Graphen veranschaulichen möchte, braucht meist viel Geduld. Die R-Erweiterung Ggplot2 bringt System in die Grafik, drückt sich in knappem Quellcode aus und bläst frischen Wind in den Alltag der Datenvisualisierung. Y1 - 2012 UR - www.linux-magazin.de/Heft-Abo/Ausgaben/2012/03/Ggplot2 IS - 3 PB - Linux New Media AG ER -