415 research outputs found
ENHANCING CLOUD SYSTEM RUNTIME TO ADDRESS COMPLEX FAILURES
As the reliance on cloud systems intensifies in our progressively digital world, understanding and reinforcing their reliability becomes more crucial than ever. Despite impressive advancements in augmenting the resilience of cloud systems, the growing incidence of complex failures now poses a substantial challenge to the availability of these systems. With cloud systems continuing to scale and increase in complexity, failures not only become more elusive to detect but can also lead to more catastrophic consequences. Such failures question the foundational premises of conventional fault-tolerance designs, necessitating the creation of novel system designs to counteract them.
This dissertation aims to enhance distributed systemsâ capabilities to detect, localize, and react to complex failures at runtime. To this end, this dissertation makes contributions to address three emerging categories of failures in cloud systems. The first part delves into the investigation of partial failures, introducing OmegaGen, a tool adept at generating tailored checkers for detecting and localizing such failures. The second part grapples with silent semantic failures prevalent in cloud systems, showcasing our study findings, and introducing Oathkeeper, a tool that leverages past failures to infer rules and expose these silent issues. The third part explores solutions to slow failures via RESIN, a framework specifically designed to detect, diagnose, and mitigate memory leaks in cloud-scale infrastructures, developed in collaboration with Microsoft Azure. The dissertation concludes by offering insights into future directions for the construction of reliable cloud systems
LIPIcs, Volume 251, ITCS 2023, Complete Volume
LIPIcs, Volume 251, ITCS 2023, Complete Volum
Space Oddity: Space Cybersecurity Lessons from a Simulated OPS-SAT Attack
The space industry is currently experiencing a rapid transformation, driven by innovations both in space and on the ground. Lower access barriers to orbit and the widespread use of commercial off-the-shelf components have facilitated the rise of CubeSats. These small satellites, with their modular design and cost-effectiveness, enable smaller teams to engage in space operations and larger players to conduct groundbreaking technological demonstrations. Furthermore, decreasing launch costs and on-demand access to ground station services have encouraged more players to join the space industry, fostering an agile and diverse environment for experimentation. However, this growth is accompanied by significant cybersecurity challenges that demand urgent attention. Historically, the space industry has relied on security-through-obscurity, but this approach can no longer be tolerated as the industry opens up to new players and technologies. This work aims to address the often-dismissed matter of securing space vehicles, using OPS-SAT, one of the most advanced CubeSat missions, as a case study. Despite its remarkable capabilities, OPS-SAT is not immune to the general dismissal of cybersecurity that plagues the industry. This work will employ a demonstrative approach, devising and implementing an attack scenario against OPS-SAT. The chosen attacker model for this scenario is that of a malicious user with limited to no cybersecurity knowledge, reflecting the reality that attackers with varying degrees of expertise can pose a threat. While keeping the attack as simple as possible, the goal is to demonstrate the potential damage that could be caused. The findings of this work illustrate that the rapid pace of development in the space industry should be accompanied by an equally enthusiastic and vigilant security force. The importance of addressing cybersecurity concerns becomes evident as the industry evolves and attracts more players, emphasizing the need for a proactive and robust security posture to safeguard space missions and future infrastructures
Anpassen verteilter eingebetteter Anwendungen im laufenden Betrieb
The availability of third-party apps is among the key success factors for software ecosystems: The users benefit from more features and innovation speed, while third-party solution vendors can leverage the platform to create successful offerings.
However, this requires a certain decoupling of engineering activities of the different parties not achieved for distributed control systems, yet.
While late and dynamic integration of third-party components would be required, resulting control systems must provide high reliability regarding real-time requirements, which leads to integration complexity.
Closing this gap would particularly contribute to the vision of software-defined manufacturing, where an ecosystem of modern IT-based control system components could lead to faster innovations due to their higher abstraction and availability of various frameworks.
Therefore, this thesis addresses the research question:
How we can use modern IT technologies and enable independent evolution and easy third-party integration of software components in distributed control systems, where deterministic end-to-end reactivity is required, and especially, how can we apply distributed changes to such systems consistently and reactively during operation?
This thesis describes the challenges and related approaches in detail and points out that existing approaches do not fully address our research question.
To tackle this gap, a formal specification of a runtime platform concept is presented in conjunction with a model-based engineering approach.
The engineering approach decouples the engineering steps of component definition, integration, and deployment.
The runtime platform supports this approach by isolating the components, while still offering predictable end-to-end real-time behavior.
Independent evolution of software components is supported through a concept for synchronous reconfiguration during full operation, i.e., dynamic orchestration of components.
Time-critical state transfer is supported, too, and can lead to bounded quality degradation, at most.
The reconfiguration planning is supported by analysis concepts, including simulation of a formally specified system and reconfiguration, and analyzing potential quality degradation with the evolving dataflow graph (EDFG) method.
A platform-specific realization of the concepts, the real-time container architecture, is described as a reference implementation.
The model and the prototype are evaluated regarding their feasibility and applicability of the concepts by two case studies.
The first case study is a minimalistic distributed control system used in different setups with different component variants and reconfiguration plans to compare the model and the prototype and to gather runtime statistics.
The second case study is a smart factory showcase system with more challenging application components and interface technologies.
The conclusion is that the concepts are feasible and applicable, even though the concepts and the prototype still need to be worked on in future -- for example, to reach shorter cycle times.Eine groĂe Auswahl von Drittanbieter-Lösungen ist einer der SchlĂŒsselfaktoren fĂŒr Software Ecosystems:
Nutzer profitieren vom breiten Angebot und schnellen Innovationen, wĂ€hrend Drittanbieter ĂŒber die Plattform erfolgreiche Lösungen anbieten können.
Das jedoch setzt eine gewisse Entkopplung von Entwicklungsschritten der Beteiligten voraus, welche fĂŒr verteilte Steuerungssysteme noch nicht erreicht wurde.
WĂ€hrend Drittanbieter-Komponenten möglichst spĂ€t -- sogar Laufzeit -- integriert werden mĂŒssten, mĂŒssen Steuerungssysteme jedoch eine hohe ZuverlĂ€ssigkeit gegenĂŒber Echtzeitanforderungen aufweisen, was zu IntegrationskomplexitĂ€t fĂŒhrt.
Dies zu lösen wĂŒrde insbesondere zur Vision von Software-definierter Produktion beitragen, da ein Ecosystem fĂŒr moderne IT-basierte Steuerungskomponenten wegen deren höherem Abstraktionsgrad und der Vielzahl verfĂŒgbarer Frameworks zu schnellerer Innovation fĂŒhren wĂŒrde.
Daher behandelt diese Dissertation folgende Forschungsfrage:
Wie können wir moderne IT-Technologien verwenden und unabhĂ€ngige Entwicklung und einfache Integration von Software-Komponenten in verteilten Steuerungssystemen ermöglichen, wo Ende-zu-Ende-Echtzeitverhalten gefordert ist, und wie können wir insbesondere verteilte Ănderungen an solchen Systemen konsistent und im Vollbetrieb vornehmen?
Diese Dissertation beschreibt Herausforderungen und verwandte AnsÀtze im Detail und zeigt auf, dass existierende AnsÀtze diese Frage nicht vollstÀndig behandeln.
Um diese LĂŒcke zu schlieĂen, beschreiben wir eine formale Spezifikation einer Laufzeit-Plattform und einen zugehörigen Modell-basierten Engineering-Ansatz.
Dieser Ansatz entkoppelt die Design-Schritte der Entwicklung, Integration und des Deployments von Komponenten.
Die Laufzeit-Plattform unterstĂŒtzt den Ansatz durch Isolation von Komponenten und zugleich Zeit-deterministischem Ende-zu-Ende-Verhalten.
UnabhĂ€ngige Entwicklung und Integration werden durch Konzepte fĂŒr synchrone Rekonfiguration im Vollbetrieb unterstĂŒtzt, also durch dynamische Orchestrierung.
Dies beinhaltet auch Zeit-kritische Zustands-Transfers mit höchstens begrenzter QualitĂ€tsminderung, wenn ĂŒberhaupt.
Rekonfigurationsplanung wird durch Analysekonzepte unterstĂŒtzt, einschlieĂlich der Simulation formal spezifizierter Systeme und Rekonfigurationen und der Analyse der etwaigen QualitĂ€tsminderung mit dem Evolving Dataflow Graph (EDFG).
Die Real-Time Container Architecture wird als Referenzimplementierung und Evaluationsplattform beschrieben.
Zwei Fallstudien untersuchen Machbarkeit und NĂŒtzlichkeit der Konzepte.
Die erste verwendet verschiedene Varianten und Rekonfigurationen eines minimalistischen verteilten Steuerungssystems, um Modell und Prototyp zu vergleichen sowie Laufzeitstatistiken zu erheben.
Die zweite Fallstudie ist ein Smart-Factory-Demonstrator, welcher herausforderndere Applikationskomponenten und Schnittstellentechnologien verwendet.
Die Konzepte sind den Studien nach machbar und nĂŒtzlich, auch wenn sowohl die Konzepte als auch der Prototyp noch weitere Arbeit benötigen -- zum Beispiel, um kĂŒrzere Zyklen zu erreichen
A War of Words: The Forms and Functions of Voice-Over in the American World War II Film â An Interdisciplinary Analysis
Aside from being American World War II films, what else do the following films have in common? The Big Red One; Hacksaw Ridge; Harts War; Mister Roberts; Stalag 17; and The Thin Red Line â all have voice-over in them. These, and hundreds of other war films have voice-overs that are sometimes the thoughts of a fearful soldier; the wry observations of a participant-observer; or the declarations of all-knowing authoritative figures. There are voice-overs blasted out through a ships PA system; as the reading of a heart-breaking letter; or as the words of a dead comrade, heard again in the mind of a haunted soldier. This thesis questions why is voice-over such a recurring phenomenon in these films? Why is it conveyed in so many different forms? What are the terms for those different forms? What are their narrative functions?
A core component of this thesis is a new taxonomy of the six distinct forms of voice-over: acousmatic, audioemic, epistolary, objective, omniscient, and subjective. However, the project is more than a structuralist taxonomy that merely serves to identify, and define those forms. It is also a close examination of their narrative functions beyond the unimaginative trope that voice-over in war films is simply a convenient storytelling device. Through interdisciplinarity â combined with a realist framework â I probe the correlations between: the conditions, codification, and suppression of speech within the U.S. military, and the manifestations of that experience through the cinematic device, and genre convention of voice-over.
In addition, I present a radically new interpretation of the voice-overs in The Thin Red Line (Terrence Malick, 1998) as being both a choric meta-memorial to James Jones; and a Greek tragedy â with its replication of the stagecraft of Aeschylus, in its use of the cosmic frame, and the inclusion of a collective character, which I have named âThe Chorus of Unknown Soldiersâ.
The overall result is a more logical, and nuanced explanation of the forms, functions, and prevalent use of voice-over in the American World War II film
Transcriptomics in Neurodegenerative Disease
Alzheimerâs (AD) and Parkinsonâs (PD) are primary neurodegenerative diseases (NDs) worldwide. Their complex mechanisms, illuminated by neuropathological studies and modern biomedical tools, call for non-invasive biomarkers, preferably from blood, for early detection, differentiating from regular aging.
Omics advancements, especially genomics and transcriptomics, have deepened our molecular understanding of NDs, helping segregate patients based on distinct molecular attributes and refining biomarker clarity.
Our research used RNA sequencing (RNA-seq) to analyze transcriptomes from the dorsolateral prefrontal cortex (DLPFC/BA9), whole blood (WB), and peripheral blood mononuclear cells (PBMC) using data from the Sequence Read Archive (SRA), negating in-house sequencing. With single nucleotide polymorphisms (SNPs), we explored shared pathological occurrences between AD and PD, investigating if ND brain molecular routes manifest in blood.
Applying differential gene expression and a random forest machine-learning technique, our data revealed a scarce overlap between AD and PD. Noteworthy AD markers like Mef2C in AD-DLPFC/BA9 and TMED7 were identified. AD blood markers emphasized cilia-driven TLR4/NF-ÎșB activation and Fyn. In PD, SNARE proteins, e.g., VAMP2 and STX1A, suggested connections between α-syn and SNARE protein reshuffling, implicating synaptic malfunction.
Genome-wide association studies (GWAS) affirmed certain discoveries. Both NDs showed overlaps in the brain and blood. Mainly, VEGF-A and inositol polyphosphates (InsPs) were detected. AD blood samples chiefly exhibited elements tied to AÎČ aggregation and tau irregularities.
Further, eQTL and sQTL mapping illuminated the roles of GWAS-associated markers in AD and PD susceptibility, with shifts in gene expression and splicing events affecting both NDs.
The present work emphasizes harnessing GWAS and QTL data to decipher ND complexities, urging continued research for therapeutic ND solutions
Energy-Sustainable IoT Connectivity: Vision, Technological Enablers, Challenges, and Future Directions
Technology solutions must effectively balance economic growth, social equity,
and environmental integrity to achieve a sustainable society. Notably, although
the Internet of Things (IoT) paradigm constitutes a key sustainability enabler,
critical issues such as the increasing maintenance operations, energy
consumption, and manufacturing/disposal of IoT devices have long-term negative
economic, societal, and environmental impacts and must be efficiently
addressed. This calls for self-sustainable IoT ecosystems requiring minimal
external resources and intervention, effectively utilizing renewable energy
sources, and recycling materials whenever possible, thus encompassing energy
sustainability. In this work, we focus on energy-sustainable IoT during the
operation phase, although our discussions sometimes extend to other
sustainability aspects and IoT lifecycle phases. Specifically, we provide a
fresh look at energy-sustainable IoT and identify energy provision, transfer,
and energy efficiency as the three main energy-related processes whose
harmonious coexistence pushes toward realizing self-sustainable IoT systems.
Their main related technologies, recent advances, challenges, and research
directions are also discussed. Moreover, we overview relevant performance
metrics to assess the energy-sustainability potential of a certain technique,
technology, device, or network and list some target values for the next
generation of wireless systems. Overall, this paper offers insights that are
valuable for advancing sustainability goals for present and future generations.Comment: 25 figures, 12 tables, submitted to IEEE Open Journal of the
Communications Societ
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