Equatorial waves resolved by balloon-borne Global Navigation Satellite System radio occultation in the Strateole-2 campaign

Current climate models have difficulty representing realistic wave–mean flow interactions, partly because the contribution from waves with fine vertical scales is poorly known. There are few direct observations of these waves, and most models have difficulty resolving them. This observational challenge cannot be addressed by satellite or sparse ground-based methods. The Strateole-2 long-duration stratospheric superpressure balloons that float with the horizontal wind on constant-density surfaces provide a unique platform for wave observations across a broad range of spatial and temporal scales. For the first time, balloon-borne Global Navigation Satellite System (GNSS) radio occultation (RO) is used to provide high-vertical-resolution equatorial wave observations. By tracking navigation signal refractive delays from GPS satellites near the horizon, 40–50 temperature profiles were retrieved daily, from balloon flight altitude (∼20 km) down to 6–8 km altitude, forming an orthogonal pattern of observations over a broad area (±400–500 km) surrounding the flight track. The refractivity profiles show an excellent agreement of better than 0.2 % with co-located radiosonde, spaceborne COSMIC-2 RO, and reanalysis products. The 200–500 m vertical resolution and the spatial and temporal continuity of sampling make it possible to extract properties of Kelvin waves and gravity waves with vertical wavelengths as short as 2–3 km. The results illustrate the difference in the Kelvin wave period (20 vs. 16 d) in the Lagrangian versus ground-fixed reference and as much as a 20 % difference in amplitude compared to COSMIC-2, both of which impact estimates of momentum flux. A small dataset from the extra Galileo, GLONASS, and BeiDou constellations demonstrates the feasibility of nearly doubling the sampling density in planned follow-on campaigns when data with full equatorial coverage will contribute to a better estimate of wave forcing on the quasi-biennial oscillation (QBO) and improved QBO representation in models.</p

Gravity waves excited during a minor sudden stratospheric warming

An exceptionally deep upper-air sounding launched from Kiruna airport (67.82 degrees N, 20.33 degrees E) on 30 January 2016 stimulated the current investigation of internal gravity waves excited during a minor sudden stratospheric warming (SSW) in the Arctic winter 2015/16. The analysis of the radiosonde profile revealed large kinetic and potential energies in the upper stratosphere without any simultaneous enhancement of upper tropospheric and lower stratospheric values. Upward-propagating inertia-gravity waves in the upper stratosphere and downward-propagating modes in the lower stratosphere indicated a region of gravity wave generation in the stratosphere. Two-dimensional wavelet analysis was applied to vertical time series of temperature fluctuations in order to determine the vertical propagation direction of the stratospheric gravity waves in 1-hourly high-resolution meteorological analyses and short-term forecasts. The separation of upward- and downward-propagating waves provided further evidence for a stratospheric source of gravity waves. The scale-dependent decomposition of the flow into a balanced component and inertia-gravity waves showed that coherent wave packets preferentially occurred at the inner edge of the Arctic polar vortex where a sub-vortex formed during the minor SSW

Definition and Verification of Security Configurations of Cyber-Physical Systems

The proliferation of Cyber-Physical Systems (CPSs) is rais ing serious security challenges. These are complex systems, integrating physical elements into automated networked systems, often containing a variety of devices, such as sensors and actuators, and requiring complex management and data storage. This makes the construction of secure CPSs a challenge, requiring not only an adequate specification of secu rity requirements and needs related to the business domain but also an adaptation and concretion of these requirements to define a security configuration of the CPS where all its components are related. Derived from the complexity of the CPS, their configurations can be incorrect according to the requirements, and must be verified. In this paper, we propose a grammar for specifying business domain security requirements based on the CPS components. This will allow the definition of security requirements that, through a defined security feature model, will result in a configuration of services and security properties of the CPS, whose correctness can be verified. For this last stage, we have created a cata logue of feature models supported by a tool that allows the automatic verification of security configurations. To illustrate the results, the pro posal has been applied to automated verification of requirements in a hydroponic system scenario.Ministerio de Ciencia y Tecnología RTI2018-094283-B-C33 (ECLIPSE)Junta de Andalucía METAMORFOSIS (US-1381375)Junta de Castilla.La Mancha SBPLY-17-180501-000202 (GENESIS

The North Atlantic Waveguide and Downstream Impact Experiment

The North Atlantic Waveguide and Downstream Impact Experiment (NAWDEX) explored the impact of diabatic processes on disturbances of the jet stream and their influence on downstream high-impact weather through the deployment of four research aircraft, each with a sophisticated set of remote sensing and in situ instruments, and coordinated with a suite of ground-based measurements. A total of 49 research flights were performed, including, for the first time, coordinated flights of the four aircraft: the German High Altitude and Long Range Research Aircraft (HALO), the Deutsches Zentrum für Luft- und Raumfahrt (DLR) Dassault Falcon 20, the French Service des Avions Français Instrumentés pour la Recherche en Environnement (SAFIRE) Falcon 20, and the British Facility for Airborne Atmospheric Measurements (FAAM) BAe 146. The observation period from 17 September to 22 October 2016 with frequently occurring extratropical and tropical cyclones was ideal for investigating midlatitude weather over the North Atlantic. NAWDEX featured three sequences of upstream triggers of waveguide disturbances, as well as their dynamic interaction with the jet stream, subsequent development, and eventual downstream weather impact on Europe. Examples are presented to highlight the wealth of phenomena that were sampled, the comprehensive coverage, and the multifaceted nature of the measurements. This unique dataset forms the basis for future case studies and detailed evaluations of weather and climate predictions to improve our understanding of diabatic influences on Rossby waves and the downstream impacts of weather systems affecting Europe

Resource-aware dynamic task-allocation in clusters of embedded smart cameras by mobile agents

Abstract – This paper presents a dynamic task allocation method for smart cameras targeting traffic surveillance. Since our target platforms are distributed embedded systems with limited resources, the task allocation has to be light-weight, flexible as well as scalable and has to support real-time requirements. Therefore, surveillance tasks are not allocated to smart cameras directly, but to groups of smart cameras, so called surveillance clusters. We formulate the allocation problem as a distributed constraint satisfaction problem (DCSP) and present a distributed method for finding feasible allocations. Finally, a cost function is used to determine the optimal allocation of tasks. We have realized this dynamic task allocation using heterogeneous, mobile agents which utilize their agencies and our embedded software framework to find the most appropriate mapping of tasks in a distributed manner. The dynamic task allocation has been implemented on our smart cameras (SmartCam) which are comprised of a network processor and several digital signal processors (DSPs) and provide a complex software framework. Kurzfassung – Diese Arbeit präsentiert eine Methodik zur dynamischen Verteilung von Aufgaben in einem Verkehrsüberwachungssystem, welches aus intelligenten Kameras besteht. Da wir uns hier mit verteilten, eingebetteten Systemen mit eingeschränkten Ressourcen beschäftigen, muß diese Aufgabenverteilung schlank, flexibel und skalierbar sein. Das System muß außerdem Echtzeitanforderungen genügen, sowohl die Verteilung der Aufgaben, wie die Aufgaben selbst. Um eine effektive Verteilung von Aufgaben gewährleisten zu können, werden Aufgaben nicht eine

A Method for Dynamic Allocation of Tasks in Clusters of Embedded Smart Cameras

Abstract- This paper presents a dynamic task allocation method for smart cameras targeting traffic surveillance. Since our target platforms are distributed embedded systems with limited resources, the task allocation has to be light-weight, flexible as well as scalable and has to support real-time requirements. Therefore, surveillance tasks are not allocated to smart cameras directly, but to groups of smart cameras, so called surveillance clusters. We formulate the allocation problem as a distributed constraint satisfaction problem (DCSP) and present a distributed method for finding feasible allocations. Finally, a cost function is used to determine the optimal allocation of tasks. We have realized this dynamic task allocation using heterogeneous, mobile agents which utilize their agencies and our embedded software framework to find the most appropriate mapping of tasks in a distributed manner. The dynamic task allocation has been implemented on our smart cameras (SmartCam) which are comprised of a network processor and several digital signal processors (DSPs) and provide a complex software framework. Keywords: Real-time mapping; agent system; embedded system; real-time.

Aspects of the negative mode problem in quantum tunneling with gravity

Some solutions describing vacuum decay exhibit a catastrophic instability. This, so-called negative mode problem in quantum tunneling with gravity, was discovered 34 years ago and in spite of the fact that in these years many different groups worked on this topic, it has still not been resolved. Here, we briefly summarize the current status of the problem and investigate properties of the bounces, numerically and analytically for physically interesting potentials. In the framework of the Hamiltonian approach we show that for generic polynomial potentials the negative mode problem could arise at energies much lower than the Planck mass, indicating that the negative mode problem is not related to physics at the Planck scale. At the same time we find that for a Higgs like potential, as it appears in the standard model, the problem does not appear at realistic values of the potential's parameters but only at the Planck scale

Integrating multi-camera tracking into a dynamic task allocation system for smart cameras

This paper reports on the integration of multi-camera tracking into an agent-based framework, which features autonomous task allocation for smart cameras targeting traffic surveillance. Since our target platforms are distributed embedded systems with limited resources, the trackers may only be active, if the target is in the camera’s field of view. Consequently, the tracking algorithm has to migrate from camera to camera in order to follow the target, whereas the decision when and whereto the migration takes place is reached autonomously by the tracker. Consequently, no central control host is required. We further present different strategies on when to migrate a tracker, and how to determine the camera which will observe the tracked object subsequently. We have realized the tracker’s control by using heterogeneous mobile agents, which employ a state-of-the-art tracking algorithm for tracking. The tracking system has been implemented on our smart cameras (SmartCam) which are comprised of a network processor and several digital signal processors (DSPs) and provide a complex software framework