application cost-aware cloud provisioning

Οι πλατφόρμες νέφους επιτρέπουν στους ιδιοκτήτες εφαρμογών την ενοικίαση πόρων, προκειμένου να επεκτείνουν δυναμικά τη συνολική υπολογιστική ισχύ των υποδομών τους. Τα χαρακτηριστικά και οι τιμές των πόρων αυτών συνήθως ποικίλουν. Οι πάροχοι νέφους διασφαλίζουν την ποιότητα υπηρεσίας μέσω εγγυήσεων (Service Layer Agreements) και πληρώνουν ποινή όταν μια εγγύηση παραβιάζεται. Συνηθως, οι βασισμένες στο νέφος εφαρμογές να προσφέρουν και αυτές τέτοιες εγγυήσεις στους χρήστες. Σε ένα δυναμικό περιβάλλον, όπου ο χρήστης εκτελεί εφαρμογές στο ιδιωτικό νέφος και μπορούν να προσθαφαιρούν κόμβους από πάροχους (δημόσιου) νέφους 2 διαφορετικά είδη SLAs υπάρχουν (i) το SLA που προσφέρεται από την εφαρμογή στους τελικούς χρήστες και (ii) το SLA που προσφέρεται από τους παρόχους νέφους στην εφαρμογή. Έτσι, μια ποινή για παραβίαση SLA από την εφαρμογή στους τελικούς χρήστες μπορεί να είναι χαμηλότερη αν παραβιάζεται και το SLA του παρόχου δημοσίου νέφους. Αυτή η ιδιότητα καθιστά τον υπολογισμό του συνολικού κόστους λειτουργίας περίπλοκο αλλά επεκτείνει το χώρο αναζήτησης των επιλογών με το χαμηλότερο συνολικό κόστος. Σε αυτήν τη διπλωματική εργασία παρουσιάζουμε έναν αλγόριθμο παροχής πόρων NoSQL εφαρμογών, που στοχεύει στην ελαχιστοποίηση του συνολικού κόστους της εφαρμογής λαμβάνοντας υπόψη τις ιδιότητες ελαστικότητας της εφαρμογής αυτής σε ένα ετερογενές περιβάλλον και είναι βασισμένος σε ‘‘look-ahead’’ βελτιστοποίησηCloud computing platforms allow application owners to rent resources in order to expand dynamically the overall computational power of their infrastructure. The resources characteristics and lease prices usually vary. Cloud providers ensure the Quality of Service through Service Layer Agreements (SLAs) and pay a penalty when these agreements are violated. Usually, cloud-based applications also offer SLAs to the users. In a dynamic environment, where a user is running applications on her private cloud and add/remove nodes from (public) cloud providers, 2 types of SLAs exist (i) the SLA offered by the application to the end users and (ii) the SLA offered by the cloud providers to the application. Thus, a penalty for an SLA violation from the application to the end users might be lower if the SLA from the public cloud provider is also violated. This property makes the calculation of the total operational cost complex, but also expands the search space of choices with lower total cost. In this thesis we present an application-cost aware resource provisioning algorithm for NoSQL applications that aims to minimize the application total cost by taking into account the elasticity properties of that application in a heterogeneous environment and is based on look-ahead optimization

Helmholtz Portfolio Theme Large-Scale Data Management and Analysis (LSDMA)

The Helmholtz Association funded the "Large-Scale Data Management and Analysis" portfolio theme from 2012-2016. Four Helmholtz centres, six universities and another research institution in Germany joined to enable data-intensive science by optimising data life cycles in selected scientific communities. In our Data Life cycle Labs, data experts performed joint R&D together with scientific communities. The Data Services Integration Team focused on generic solutions applied by several communities

Approaching algorithmic power

Contemporary power manifests in the algorithmic. Emerging quite recently as an object of study within media and communications, cultural research, gender and race studies, and urban geography, the algorithm often seems ungraspable. Framed as code, it becomes proprietary property, black-boxed and inaccessible. Framed as a totality, its becomes overwhelmingly complex, incomprehensible in its operations. Framed as a procedure, it becomes a technique to be optimised, bracketing out the political. In struggling to adequately grasp the algorithmic as an object of study, to unravel its mechanisms and materialities, these framings offer limited insight into how algorithmic power is initiated and maintained. This thesis instead argues for an alternative approach: firstly, that the algorithmic is coordinated by a coherent internal logic, a knowledge-structure that understands the world in particular ways; second, that the algorithmic is enacted through control, a material and therefore observable performance which purposively influences people and things towards a predetermined outcome; and third, that this complex totality of architectures and operations can be productively analysed as strategic sociotechnical clusters of machines. This method of inquiry is developed with and tested against four contemporary examples: Uber, Airbnb, Amazon Alexa, and Palantir Gotham. Highly profitable, widely adopted and globally operational, they exemplify the algorithmic shift from whiteboard to world. But if the world is productive, it is also precarious, consisting of frictional spaces and antagonistic subjects. Force cannot be assumed as unilinear, but is incessantly negotiated—operations of parsing data and processing tasks forming broader operations that strive to establish subjectivities and shape relations. These negotiations can fail, destabilised by inadequate logics and weak control. A more generic understanding of logic and control enables a historiography of the algorithmic. The ability to index information, to structure the flow of labor, to exert force over subjects and spaces— these did not emerge with the microchip and the mainframe, but are part of a longer lineage of calculation. Two moments from this lineage are examined: house-numbering in the Habsburg Empire and punch-card machines in the Third Reich. Rather than revolutionary, this genealogy suggests an evolutionary process, albeit uneven, linking the computation of past and present. The thesis makes a methodological contribution to the nascent field of algorithmic studies. But more importantly, it renders algorithmic power more intelligible as a material force. Structured and implemented in particular ways, the design of logic and control construct different versions, or modalities, of algorithmic power. This power is political, it calibrates subjectivities towards certain ends, it prioritises space in specific ways, and it privileges particular practices whilst suppressing others. In apprehending operational logics, the practice of method thus foregrounds the sociopolitical dimensions of algorithmic power. As the algorithmic increasingly infiltrates into and governs the everyday, the ability to understand, critique, and intervene in this new field of power becomes more urgent

A conceptual framework for uncertainty in software systems and its application to software architectures

The development and operation of a software system involve many aspects including processes, artefacts, infrastructure and environments. Most of these aspects are vulnerable to uncertainty. Thus, the identification, representation and management of uncertainty in software systems is important and will be of interest to many stakeholders in software systems. The hypothesis of this work is that such consideration would benefit from an underlying conceptual framework that allows stakeholders to characterise, analyse and mitigate uncertainties. This PhD proposes a framework to provide a generic foundation for the systematic and explicit consideration of uncertainty in software systems by consolidating and extending existing approaches to dealing with uncertainty, which are typically tailored to specific domains or artefacts. The thesis applies the framework to software architectures, which are fundamental in determining the structure, behaviour and qualities of software systems and are thus suited to serve as an exemplar artefact. The framework is evaluated using the software architectures of case studies from 3 different domains. The contributions of the research to the study of uncertainty in software systems include a literature review of approaches to managing uncertainty in software architecture, a review of existing work on uncertainty frameworks related to software systems, a conceptual framework for uncertainty in software systems, a conceptualisation of the workbench infrastructure as a basis for building an uncertainty consideration workbench of tools for representing uncertainty as part of software architecture descriptions, and an evaluation of the uncertainty framework using three software architecture case studies

Software Maintenance At Commit-Time

Software maintenance activities such as debugging and feature enhancement are known to be challenging and costly, which explains an ever growing line of research in software maintenance areas including mining software repository, default prevention, clone detection, and bug reproduction. The main goal is to improve the productivity of software developers as they undertake maintenance tasks. Existing tools, however, operate in an offline fashion, i.e., after the changes to the systems have been made. Studies have shown that software developers tend to be reluctant to use these tools as part of a continuous development process. This is because they require installation and training, hindering their integration with developers’ workflow, which in turn limits their adoption. In this thesis, we propose novel approaches to support software developers at commit-time. As part of the developer’s workflow, a commit marks the end of a given task. We show how commits can be used to catch unwanted modifications to the system, and prevent the introduction of clones and bugs, before these modifications reach the central code repository. We also propose a bug reproduction technique that is based on model checking and crash traces. Furthermore, we propose a new way for classifying bugs based on the location of fixes that can serve as the basis for future research in this field of study. The techniques proposed in this thesis have been tested on over 400 open and closed (industrial) systems, resulting in high levels of precision and recall. They are also scalable and non-intrusive

Cyber Law and Espionage Law as Communicating Vessels

Professor Lubin\u27s contribution is Cyber Law and Espionage Law as Communicating Vessels, pp. 203-225. Existing legal literature would have us assume that espionage operations and “below-the-threshold” cyber operations are doctrinally distinct. Whereas one is subject to the scant, amorphous, and under-developed legal framework of espionage law, the other is subject to an emerging, ever-evolving body of legal rules, known cumulatively as cyber law. This dichotomy, however, is erroneous and misleading. In practice, espionage and cyber law function as communicating vessels, and so are better conceived as two elements of a complex system, Information Warfare (IW). This paper therefore first draws attention to the similarities between the practices – the fact that the actors, technologies, and targets are interchangeable, as are the knee-jerk legal reactions of the international community. In light of the convergence between peacetime Low-Intensity Cyber Operations (LICOs) and peacetime Espionage Operations (EOs) the two should be subjected to a single regulatory framework, one which recognizes the role intelligence plays in our public world order and which adopts a contextual and consequential method of inquiry. The paper proceeds in the following order: Part 2 provides a descriptive account of the unique symbiotic relationship between espionage and cyber law, and further explains the reasons for this dynamic. Part 3 places the discussion surrounding this relationship within the broader discourse on IW, making the claim that the convergence between EOs and LICOs, as described in Part 2, could further be explained by an even larger convergence across all the various elements of the informational environment. Parts 2 and 3 then serve as the backdrop for Part 4, which details the attempt of the drafters of the Tallinn Manual 2.0 to compartmentalize espionage law and cyber law, and the deficits of their approach. The paper concludes by proposing an alternative holistic understanding of espionage law, grounded in general principles of law, which is more practically transferable to the cyber realmhttps://www.repository.law.indiana.edu/facbooks/1220/thumbnail.jp