Fundamental Approaches to Software Engineering

This open access book constitutes the proceedings of the 24th International Conference on Fundamental Approaches to Software Engineering, FASE 2021, which took place during March 27–April 1, 2021, and was held as part of the Joint Conferences on Theory and Practice of Software, ETAPS 2021. The conference was planned to take place in Luxembourg but changed to an online format due to the COVID-19 pandemic. The 16 full papers presented in this volume were carefully reviewed and selected from 52 submissions. The book also contains 4 Test-Comp contributions

Doctor of Philosophy

dissertationThis dissertation explores three key facets of software algorithms for custom hardware ray tracing: primitive intersection, shading, and acceleration structure construction. For the first, primitive intersection, we show how nearly all of the existing direct three-dimensional (3D) ray-triangle intersection tests are mathematically equivalent. Based on this, a genetic algorithm can automatically tune a ray-triangle intersection test for maximum speed on a particular architecture. We also analyze the components of the intersection test to determine how much floating point precision is required and design a numerically robust intersection algorithm. Next, for shading, we deconstruct Perlin noise into its basic parts and show how these can be modified to produce a gradient noise algorithm that improves the visual appearance. This improved algorithm serves as the basis for a hardware noise unit. Lastly, we show how an existing bounding volume hierarchy can be postprocessed using tree rotations to further reduce the expected cost to traverse a ray through it. This postprocessing also serves as the basis for an efficient update algorithm for animated geometry. Together, these contributions should improve the efficiency of both software- and hardware-based ray tracers

Structural model checking

The introduction of symbolic approaches, based on Binary Decision Diagrams (BDD), to Model Checking has led to significant improvements in Formal Verification, by allowing the analysis of very large systems, such as complex circuit designs. These were previously beyond the reach of traditional, explicit methods, due to the state space explosion phenomenon. However, after the initial success, the BDD technology has peaked, due to a similar problem, the BDD explosion.;We present a new approach to symbolic Model Checking that is based on exploiting the system structure. This technique is characterized by several unique features, including an encoding of states with Multiway Decision Diagrams (MDD) and of transitions with boolean Kronecker matrices. This approach naturally captures the property of event locality, inherently present in the class of globally asynchronous/locally synchronous systems.;The most important contribution of our work is the saturation algorithm for state space construction. Using saturation, the peak size of the MDD (luring the exploration is drastically reduced, often to sizes equal or comparable to the final MDD size, which makes it optimal in these terms. Subsequently, saturation can achieve similar reductions in runtimes. When compared to the leading state-of-the art tools based on traditional symbolic approaches, saturation is up to 100,000 times faster and uses up to 1,000 times less memory. This enables our approach to study much larger systems than ever considered. Following the success in state space exploration, we extend the applicability of the saturation algorithm to CTL Model Checking, and also to efficient generation of shortest length counterexamples for safety properties, with similar results.;This approach to automatic verification is implemented in the tool SMART. We test the new model checker on a real life, industrial size application: the NASA Runway Safety Monitor (RSM). The analysis exposes a number of potential problems with the decision procedure designed to signal all hazardous situations during takeoff and landing procedures on runways. Attempts to verify RSM with other model checkers (NuSMV, SPIN) fail due to excessive memory consumption, showing that our structural method is superior to existing symbolic approaches

Latenzzeitverbergung in datenparallelen Sprachen = [Latency Hiding in Dataparallel Languages]

Das ungünstige Verhältnis von Kommunikations- zu Rechenleistung fast aller Parallelrechner, das sich in Kommunikationslatenzzeiten von mehreren hundert bis tausend Prozessortaktzyklen manifestiert, verhindert in vielen Fällen die effziente Ausführung von kommunikationsintensiven feingranularen datenparallelen Programmen. Zur Lösung dieses Problems untersucht diese Arbeit Techniken zur Latenzzeitverbergung, die durch Vorladeoperationen die Kommunikationszeit des Netzwerkes verdecken. Der vorgeschlagene Ansatz VSCAP (Software Controlled Access Pipelining with Vector commands) erweitert bestehende Techniken um Vektorbefehle und kann die anfallenden Latenzzeiten für eine große Anzahl von Anwendungen fast vollständig verbergen. Meine Beiträge sind: - Modellierung von VSCAP, einer Erweiterung von SCAP mit Vektorbefehlen. - Entwurf von Konzepten, mit denen Kommunikationsaufträge in datenparallelen Programmen in Datenfließbänder des VSCAP-Verfahrens überführt werden können. - Implementierung dieser Konzepte und Integration in den Prototypübersetzer Kar-HPFn. Die Leistungen von VSCAP bei der Latenzzeitverbergung wurden durch Modellierung und Laufzeittests von 25 Programmen, darunter 3 kompletten Anwendungen, untersucht. Die Ergebnisse sind: - Nachweis der praktischen Einsetzbarkeit von VSCAP (und damit als Spezialfall auch SCAP) auf einem realen Rechner. - Berechnung des Grades der Latenzzeitverbergung von VSCAP und Bestätigung der Modellierung durch automatisch generierte Programme. - Bestätigung der Beschleunigung von VSCAP gegenüber SCAP um einen Faktor gleich der Vektorlänge L durch Modellierung und Messungen. - Erster Übersetzer auf Parallelrechnerarchitekturen mit gemeinsamem Adreßraum, der zur Kommunikation nur Vorladeoperationen einsetzt. - Nachweis der automatischen, für den Programmierer transparenten und effizienten Übersetzung von datenparallelen Applikationen in Programme, die zur Kommunikation das VSCAP-Verfahren anwenden, am Beispiel von HPF. - Vergleichbare Leistung von KarHPFn-generiertem VSCAP und der hochoptimierten Kommunikationsbibliothek auf der Cray T3E, bei dynamischen Kommunikationsmustern sogar ein mehr als 6-facher Laufzeitgewinn von VSCAP. - 3- bis mehr als 5-facher Laufzeitgewinn von KarHPFn-generiertem VSCAP gegenüber Portland Group HPF beim Test von drei Applikationen (Veltran, FIRE und PDE1) auf bis zu 128 Prozessoren mit identischen HPF-Quellen, bei Programmen mit großem Kommunikationsaufwand sogar mehr als ein Faktor 15

Programming Languages and Systems

This open access book constitutes the proceedings of the 29th European Symposium on Programming, ESOP 2020, which was planned to take place in Dublin, Ireland, in April 2020, as Part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2020. The actual ETAPS 2020 meeting was postponed due to the Corona pandemic. The papers deal with fundamental issues in the specification, design, analysis, and implementation of programming languages and systems

Space and Earth Sciences, Computer Systems, and Scientific Data Analysis Support, Volume 1

This Final Progress Report covers the specific technical activities of Hughes STX Corporation for the last contract triannual period of 1 June through 30 Sep. 1993, in support of assigned task activities at Goddard Space Flight Center (GSFC). It also provides a brief summary of work throughout the contract period of performance on each active task. Technical activity is presented in Volume 1, while financial and level-of-effort data is presented in Volume 2. Technical support was provided to all Division and Laboratories of Goddard's Space Sciences and Earth Sciences Directorates. Types of support include: scientific programming, systems programming, computer management, mission planning, scientific investigation, data analysis, data processing, data base creation and maintenance, instrumentation development, and management services. Mission and instruments supported include: ROSAT, Astro-D, BBXRT, XTE, AXAF, GRO, COBE, WIND, UIT, SMM, STIS, HEIDI, DE, URAP, CRRES, Voyagers, ISEE, San Marco, LAGEOS, TOPEX/Poseidon, Pioneer-Venus, Galileo, Cassini, Nimbus-7/TOMS, Meteor-3/TOMS, FIFE, BOREAS, TRMM, AVHRR, and Landsat. Accomplishments include: development of computing programs for mission science and data analysis, supercomputer applications support, computer network support, computational upgrades for data archival and analysis centers, end-to-end management for mission data flow, scientific modeling and results in the fields of space and Earth physics, planning and design of GSFC VO DAAC and VO IMS, fabrication, assembly, and testing of mission instrumentation, and design of mission operations center

BIG DATA и анализ высокого уровня : материалы конференции

В сборнике опубликованы результаты научных исследований и разработок в области BIG DATA and Advanced Analytics для оптимизации IT-решений и бизнес-решений, а также тематических исследований в области медицины, образования и экологии

ReSCon '12, Research Student Conference: Book of Abstracts

The fifth SED Research Student Conference (ReSCon2012) was hosted over three days, 18-20 June 2012, in the Hamilton Centre at Brunel University. The conference consisted of 130 oral and 70 poster presentations, based on the high quality and diverse research being conducted within the School of Engineering and Design by postgraduate research students. The conference is held annually, and ReSCon plays a key role in contributing to research and innovations within the School