26 research outputs found

    Self-adaptive online virtual network migration in network virtualization environments

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    This is the peer reviewed version of the following article: Zangiabady, M, Garcia‐Robledo, A, Gorricho, J‐L, Serrat‐Fernandez, J, Rubio‐Loyola, J. Self‐adaptive online virtual network migration in network virtualization environments. Trans Emerging Tel Tech. 2019; 30:e3692. https://doi.org/10.1002/ett.3692, which has been published in final form at https://doi.org/10.1002/ett.3692. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.In Network Virtualization Environments, the capability of operators to allocate resources in the Substrate Network (SN) to support Virtual Networks (VNs) in an optimal manner is known as Virtual Network Embedding (VNE). In the same context, online VN migration is the process meant to reallocate components of a VN, or even an entire VN among elements of the SN in real time and seamlessly to end-users. Online VNE without VN migration may lead to either over- or under-utilization of the SN resources. However, VN migration is challenging due to its computational cost and the service disruption inherent to VN components reallocation. Online VN migration can reduce migration costs insofar it is triggered proactively, not reactively, at critical times, avoiding the negative effects of both under- and over-triggering. This paper presents a novel online cost-efficient mechanism that self-adaptively learns the exact moments when triggering VN migration is likely to be profitable in the long term. We propose a novel self-adaptive mechanism based on Reinforcement Learning that determines the right trigger online VN migration times, leading to the minimization of migration costs while simultaneously considering the online VNE acceptance ratio.Peer ReviewedPostprint (author's final draft

    Seeking and Avoiding Choice Closure to Enhance Outcome Satisfaction

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    Consumers gain choice closure when they perceive a sense of finality over a past decision and limit comparisons between the selected and the forgone options. We investigate consumers’ ability to make strategic use of choice closure to enhance outcome satisfaction. Seven studies show that consumers experience greater satisfaction when they achieve choice closure with an inferior outcome and when they do not achieve choice closure with a superior outcome; however, they expect to be more satisfied by avoiding choice closure with an inferior outcome and by seeking it with a superior outcome. We provide a rationale for this experience–expectation contrast based on rule overgeneralization. Consumers form their expectation on an implicit rule learned and internalized in a context in which it is appropriate and advantageous: when they aim to increase satisfaction with a future choice; however, consumers erroneously apply the same implicit rule to a different context, one in which they aim to increase satisfaction with a past choice. We conclude that consumers are unlikely to be able to make strategic use of choice closure to enhance satisfaction with the outcome of a decision they have made

    Kokonaislukuoptimointiin perustuva koodigenerointi nÀkyvÀn datapolun arkkitehtuureille

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    As the use of embedded processors has spread throughout the society pervasively, the requirements for the processors have become much more diverse causing general purpose processors to be inefficient on many occasions. This creates the need for customized processors that are tailored for a particular use case. Transport triggered architecture is a processor architecture template that exploits the instruction level parallelism. The architecture provides the basic building blocks and means to construct custom tailored processors. Transport triggered architecture processors are statically scheduled, thus powerful instruction scheduling algorithms can bring up significant efficiency increases in terms of chip area, clock frequency, and energy consumption. This thesis proposes an integer linear programming model for the instruction scheduling problem of the transport triggered architecture. The model describes the architecture characteristics, the particular processor resource constraints, and the operation dependencies of the scheduled program. It is possible to optimize the model for various criterion, for example to achieve as energy efficient processors as possible. This scheduling algorithm was implemented to the high-level language compiler of the TTA-based Co-design Environment, which is a toolset for designing processors using the transport triggered architecture template. The model was tested and measured with example problems such as complex number arithmetics, and vector dot product. Such example algorithms are typically executed in embedded processors and parallelize reasonably well. The performance results were compared to the existing heuristic graph-based scheduling algorithm of the toolset compiler. The study indicates that the integer linear programming based instruction scheduler produced significantly shorter schedules compared to the heuristic scheduler. In addition, the amount of register access in the compiled programs was generally notably less than those of the heuristic scheduler. On the other hand, the proposed scheduler used distinctly more execution time than the heuristic scheduler

    Specification, Validation and Verification of Social, Legal, Ethical, Empathetic and Cultural Requirements for Autonomous Agents

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    Autonomous agents are increasingly being proposed for use in healthcare, assistive care, education, and other applications governed by complex human-centric norms. To ensure compliance with these norms, the rules they induce need to be unambiguously defined, checked for consistency, and used to verify the agent. In this paper, we introduce a framework for formal specification, validation and verification of social, legal, ethical, empathetic and cultural (SLEEC) rules for autonomous agents. Our framework comprises: (i) a language for specifying SLEEC rules and rule defeaters (that is, circumstances in which a rule does not apply or an alternative form of the rule is required); (ii) a formal semantics (defined in the process algebra tock-CSP) for the language; and (iii) methods for detecting conflicts and redundancy within a set of rules, and for verifying the compliance of an autonomous agent with such rules. We show the applicability of our framework for two autonomous agents from different domains: a firefighter UAV, and an assistive-dressing robot

    Crustal Structure Across the Northern Region of the Islas Marias Archipelago

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    The tectonic interaction between the Rivera and North American plates north of the Bahia de Banderas is poorly understood. The nature of the crust and where the subduction ends in the western part of the Islas Marias Archipelago are still controversial. Based on new geophysical data provided by the TsuJal project, we present the shallow and deep crustal structure of the Rivera North American plate contact zone along two seismic transects, TS09b and RTSIM01b, and the bathymetry obtained across the northern region of Maria Madre Island. Detailed bathymetric analysis allowed mapping of a series of lineaments along the study region, with two main preferred tendencies (020 050 and 290 320) associated with the evolution of the Pacific-Rivera rise and the transform faults of the Gulf of California, respectively. The shallow structure is characterized by five sedimentary basins without deformation, whose horizons are subparallel, suggesting that the sediment deposition occurred after the extension process ended. The deep structure corresponds to a transition between oceanic crust (Rivera Plate), with an average thickness of 10 km to the Islas Marias Escarpment, and a thinned continental crust, whose thickness increases toward the continent until it reaches 28 km, with a dip angle of 7 10. The absence of an accretionary prism suggests that the subduction process of the Rivera Plate beneath the North American Plate to the north of Islas Marias has ceased. In this study, we determined that the morphological expression of the northern limit of the Rivera Plate corresponds to the Islas Marias Escarpment.Comment: Frontiers in Earth Science, 202

    Prototyp-Radiatoren eines Barrel-DIRC fĂŒr das PANDA-Experiment

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    Das Antiprotonen-Experiment PANDA an der zukĂŒnftigen Beschleunigeranlage FAIR wird unter anderem Charmonium-ZustĂ€nde mit einer bis dato unerreichten Genauigkeit messen können. Um dieses Ziel zu erreichen, wird eine sehr gute TeilchenidentifikationsfĂ€higkeit verlangt. Eine gute Trennung zwischen Pionen und Kaonen wird durch den Einsatz eines Cherenkovdetektors erreicht. Die LeistungsfĂ€higkeit eines DIRC hĂ€ngt von dessen RadiatorgĂŒte ab. Um die QualitĂ€t der RadiatorstĂ€be spezifizieren zu können, wurde im Rahmen dieser Doktorarbeit eine optische Messapparatur entwickelt. Dieser Aufbau erlaubt es die Transmission sowie die OberflĂ€chenrauheit der StĂ€be zu messen. Es wurden mehrere RadiatorstĂ€be aus synthetischem Quarzglas und Acrylglas untersucht. Die Messgenauigkeit bei hochqualitativen StĂ€ben liegt fĂŒr die Transmissionsmessung bei etwa 1 Promille und fĂŒr die Rauheit bei 1-2 Angström. Die Messergebnisse bei verschiedenen WellenlĂ€ngen zeigen eine gute Übereinstimmung mit der skalaren Streutheorie, die den Zusammenhang zwischen Reflexionskoeffizienten und Rauheit beschreibt. Bei einer Strahlzeit an der GSI mit einem 2 GeV Protonenstrahl wurde ein erster Prototyp fĂŒr den Barrel-DIRC mit einem Stab aus synthetischem Quarzglas als Radiator getestet. Durch Variation des Einfallswinkels und der Position des Protonenstrahls auf dem Radiator konnten Cherenkovringe eindeutig nachgewiesen werden. Zudem wurde der Cherenkovwinkel und die Einzelphotonauflösung in guter Übereinstimmung mit dem Erwartetem und der Simulation bestimmt

    The 2011 Eruption of the Recurrent Nova T Pyxidis; the Discovery, the Pre-eruption Rise, the Pre-eruption Orbital Period, and the Reason for the Long Delay

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    We report the discovery by M. Linnolt on JD 2455665.7931 (UT 2011 April 14.29) of the sixth eruption of the recurrent nova T Pyxidis. This discovery was made just as the initial fast rise was starting, so with fast notification and response by observers worldwide, the entire initial rise was covered (the first for any nova), and with high time resolution in three filters. The speed of the rise peaked at 9 mag/day, while the light curve is well fit over only the first two days by a model with a uniformly expanding sphere. We also report the discovery by R. Stubbings of a pre-eruption rise starting 18 days before the eruption, peaking 1.1 mag brighter than its long-time average, and then fading back towards quiescence 4 days before the eruption. This unique and mysterious behavior is only the fourth known anticipatory rise closely spaced before a nova eruption. We present 19 timings of photometric minima from 1986 to February 2011, where the orbital period is fast increasing with P/dot{P}=313,000 yrs. From 2008-2011, T Pyx had a small change in this rate of increase, so that the orbital period at the time of eruption was 0.07622950+-0.00000008 days. This strong and steady increase of the orbital period can only come from mass transfer, for which we calculate a rate of 1.7-3.5x10^-7 Mo/yr. We report 6116 magnitudes between 1890 and 2011, for an average B=15.59+-0.01 from 1967-2011, which allows for an eruption in 2011 if the blue flux is nearly proportional to the accretion rate. The ultraviolet-optical-infrared spectral energy distribution is well fit by a power law with flux proportional to nu^1.0, although the narrow ultraviolet region has a tilt with a fit of \nu^{1/3}. We prove that most of the T Pyx light is not coming from a disk, or any superposition of blackbodies, but rather is coming from some nonthermal source.Comment: ApJ submitted, 62 pages, 8 figures; much added data, updated analysi

    Luminosity Measurement in the L3 Detector at LEP

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    One of the limiting factors in the determination of the electroweak parameters from cross section measurements of e+e- annihilation close to the Z pole is the precision of the luminosity measurement. The luminosity monitor of the L3 detector at LEP and the analysis of its data are described. Using a combination of a BGO calorimeter and a 3-layer silicon tracker, the absolute luminosity has been measured with an experimental precision of 0.08% in 1993 and 0.05% in 1994. The measurement relies on a detailed understanding of small-angle elastic e+e-(Bhabha) scattering from the experimental and theoretical point of view, as well as an excellent knowledge of the detector geometry
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