Towards a Model-driven Performance Prediction Approach for Internet of Things Architectures

Indisputable, security and interoperability play major concerns in Internet of Things (IoT) architectures and applications. In this paper, however, we emphasize the role and importance of performance and scalability as additional, crucial aspects in planning and building sustainable IoT solutions. IoT architectures are complicated system-of-systems that include different developer roles, development processes, organizational units, and a multilateral governance. Its performance is often neglected during development but becomes a major concern at the end of development and results in supplemental efforts, costs, and refactoring. It should not be relied on linearly scaling for such systems only by using up-to-date technologies that may promote such behavior. Furthermore, different security or interoperability choices also have a considerable impact on performance and may result in unforeseen trade-offs. Therefore, we propose and pursue the vision of a model-driven approach to predict and evaluate the performance of IoT architectures early in the system lifecylce in order to guarantee efficient and scalable systems reaching from sensors to business applications

A Pattern-based Approach towards Modular Safety Analysis and Argumentation

International audienceSafety standards recommend (if not dictate) performing many analyses during the concept phase of development as well as the early adoption of multiple measures at the architectural design level. In practice, the reuse of architectural measures or safety mechanisms is widely-spread, especially in well-understood domains, as is reusing the corresponding safety-cases aiming to document and prove the fulfillment of the underlying safety goals. Safety-cases in the automotive domain are not well-integrated into architectural models and as such do not provide comprehensible and reproducible argumentation nor any evidence for argument correctness. The reuse is mostly ad-hoc, with loss of knowledge and traceability and lack of consistency or process maturity as well as being the most widely spread and cited drawbacks.Using a simplified description of software functions and their most common error management subtypes (avoidance, detection, handling, ..) we propose to define a pattern library covering known solution algorithms and architectural measures/constraints in a seamless holistic model-based approach with corresponding tool support. The pattern libraries would comprise the requirement the pattern covers and the architecture elements/ measures / constraints required and may include deployment or scheduling strategies as well as the supporting safety case template, which would then be integrated into existing development environments. This paper explores this approach using an illustrative example

Introduction to Intelligent Decision Support and Big Data for Logistics and Supply Chain Management Minitrack

N/

Integrated Task and Message Scheduling in Time-Triggered Aeronautic Systems

This thesis presents generation techniques for task and message configurations in time-triggered IMA architectures. The commonality among the given techniques is the problem of integrated task and message scheduling for time-triggered networks. The proposed approaches allow the automatic generation of task and message schedules, which comprises certain system requirements. Our first approach solves the task and message scheduling problem by regarding it as a graph problem. We present an off-line scheduling algorithm that traverses the precedence graph. The approach integrates task scheduling at system level and message scheduling at communication level by iteratively traversing the given precedence graph. The algorithm incorporates backtracking and path extension functionality, guaranteeing the consistency of the developed schedule. The main advantage of the algorithm is that it scales up well even for large avionics applications. Furthermore, this thesis extends ongoing research into task and message scheduling based on time-triggered networks by first using model checking techniques for solving this kind of problem. We demonstrate that state-of-the-art model checking and bounded model checking techniques can be used to compute a schedule that fulfills certain system requirements. Therefore, we introduce an approach that adopts the principle of symbolic state space exploration to schedule synthesis and provides a symbolic encoding which makes it possible to guarantee an optimal solution with respect to minimizing the system’s end-to-end latency. A developed heuristic approach extends this approach in order to increase scalability by preventing from an exhaustive search through a guided, weight-based state-space exploration. The developed approaches are implemented in a framework for scheduling synthesis. This framework enables the generation and investigate certain system configurations in terms of complexity. This is done by using a complexity evaluation approach, which is developed is this thesis.Diese Arbeit präsentiert Techniken zur Generierung von integrierten Task- und Message Konfigurationen für zeitgesteuerte IMA Architekturen. Den präsentierten Ansätzen liegt das Problem der Erzeugung von integrierten Task und Message Schedules für zeitgesteuerte Netzwerke zugrunde. Die entwickelten Ansätze generieren dabei automatisch integrierte Task und Message Schedules, die speziellen Systemanforderungen genügen. Unser erster Ansatz löst das Task und Message Scheduling Problem mittels Transformierung in ein Graphen - Problem. Ein Algorithmus wird entwickelt, der den Abhängigkeitsgraphen durchläuft und dabei sowohl das Task Scheduling auf Systemebene, als auch das Message Scheduling auf Kommunikationsebene einbezieht. Der präsentierte Ansatz arbeitet iterativ und enthält Überprüfungs- und Pfad-Erweiterungs-Funktionalität, die die zeitliche Konsistenz des entwickelten Schedules garantieren. Einer der Vorteile dieses Ansatzes ist die Skalierbarkeit, die es ermöglicht, auch größere aeronautische Architekturen zu untersuchen und entsprechende Konfigurationen bereitzustellen. Ein zweiter Ansatz beschreibt und löst erstmals das gegebene Problem mit Hilfe von Model - Checking Techniken. Diese Arbeit zeigt, dass aktuelle Model - Checking und Bounded Model - Checking Techniken genutzt werden können, um integrierte Task und Message Schedules zu berechnen, die speziellen Systemeigenschaften genügen. Wir präsentieren einen Ansatz, der das Prinzip der Zustandsraumexploration zur Scheduling Synthese nutzt. Dazu entwickeln wir eine symbolische Kodierung, die es nicht nur ermöglicht gültige Konfigurationen zu finden, sondern auch solche, die optimal sind bezüglich der Minimierung der Ende-zu-Ende Latenz. Zusätzlich präsentieren wir einen heuristischen Ansatz, der es erlaubt, die Skalierbarkeit deutlich zu verbessern, indem er das Problem der erschöpfenden Suche einschränkt. Die entwickelte Heuristik führt dabei eine gesteuerte, gewichtsbasierte Erkundung des Zustandsraumes durch. Die entwickelten Ansätze sind in einem Framework zur Scheduling Synthese implementiert. Dieses Framework erlaubt die Generierung von geeigneten System Konfigurationen als auch Komplexitätsuntersuchung für verschiedene Systemarchitektur - Szenarien. Dazu wird ein Ansatz zur Evaluierung von Komplexitätsuntersuchungen entwickelt

Short Hypoxia Does not Affect Plasma Leptin in Healthy Men under Euglycemic Clamp Conditions

Leptin is involved in the endocrine control of energy expenditure and body weight regulation. Previous studies emphasize a relationship between hypoxic states and leptin concentrations. The aim of this study was to investigate the effects of acute hypoxia on leptin concentrations in healthy subjects. We examined 14 healthy men. Hypoxic conditions were induced by decreasing oxygen saturation to 75% for 30 minutes. Plasma leptin concentrations were determined at baseline, after 3 hours of euglycemic clamping, during hypoxia, and repeatedly the following 2.5 hours thereafter. Our results show an increase of plasma leptin concentrations in the course of 6 hours of hyperinsulinemic-euglycemic clamping which may reflect diurnal rhythmicity. Notwithstanding, there was no difference between levels of leptin in the hypoxic and the normoxic condition (P = .2). Since we did not find any significant changes in leptin responses upon hypoxia, plasma leptin levels do not seem to be affected by short hypoxic episodes of moderate degree

Evaluation of high-sensitivity C-reactive protein and uric acid in vericiguat-treated patients with heart failure with reduced ejection fraction

Aims: The effects of vericiguat vs. placebo on high-sensitivity C-reactive protein (hsCRP) and serum uric acid (SUA) were assessed in patients with heart failure with reduced ejection fraction (HFrEF) in the Phase 2 SOCRATES-REDUCED study (NCT01951625). Methods and results: Changes from baseline hsCRP and SUA values at 12 weeks with placebo and vericiguat (1.25 mg, 2.5 mg, 5.0 mg and 10.0 mg, respectively) were assessed. The probability of achieving an hsCRP value of ≤3.0 mg/L or SUA value of <7.0 mg/dL at week 12 was tested. Median baseline hsCRP and SUA levels were 3.68 mg/L [interquartile range (IQR) 1.41–8.41; n = 335] and 7.80 mg/dL (IQR 6.40–9.33; n = 348), respectively. Baseline-adjusted mean percentage changes in hsCRP were 0.2%, −19.5%, −24.3%, −25.7% and −31.9% in the placebo and vericiguat 1.25 mg, 2.5 mg, 5.0 mg and 10.0 mg groups, respectively; significance vs. placebo was observed in the vericiguat 10.0 mg group (P = 0.035). Baseline-adjusted mean percentage changes in SUA were 5.0%, −1.3%, −1.1%, −3.5% and −5.3% in the placebo, and vericiguat 1.25 mg, 2.5 mg, 5.0 mg and 10.0 mg groups, respectively; significance vs. placebo was observed in the 5.0 mg and 10.0 mg groups (P = 0.0202 and P = 0.004, respectively). Estimated probability for an end-of-treatment hsCRP value of ≤3.0 mg/L and SUA value of <7.0 mg/dL was higher with vericiguat compared with placebo. The effect was dose-dependent, with the greatest effect observed in the 10.0 mg group. Conclusions: Vericiguat treatment for 12 weeks was associated with reductions in hsCRP and SUA, and a higher likelihood of achieving an hsCRP value of ≤3.0 mg/L and SUA value of <7.0 mg/dL

Rabi oscillations in a superconducting nanowire circuit

We investigate the circuit quantum electrodynamics of anharmonic superconducting nanowire oscillators. The sample circuit consists of a capacitively shunted nanowire with a width of about 20 nm and a varying length up to 350 nm, capacitively coupled to an on-chip resonator. By applying microwave pulses we observe Rabi oscillations, measure coherence times and the anharmonicity of the circuit. Despite the very compact design, simple top-down fabrication and high degree of disorder in the oxidized (granular) aluminum material used, we observe lifetimes in the microsecond range