391 research outputs found
Cosmic-ray confinement in radio bubbles by micromirrors
No full textRadio bubbles, ubiquitous features of the intracluster medium around active
galactic nuclei, are known to rise buoyantly for multiple scale heights through
the intracluster medium (ICM). It is an open question how the bubbles can
retain their high-energy cosmic-ray content over such distances. We propose
that the enhanced scattering of cosmic rays due to micromirrors generated in
the ICM, as proposed recently by Reichherzer et al. (2023), is a viable
mechanism for confining the cosmic rays within bubbles and can qualitatively
reproduce their morphology. We discuss the observational implications of such a
model of cosmic-ray confinement.Comment: 10 pages, 6 figure
Prise en compte des effets temporels pour une meilleure coordination des observations multi-messagers
No full textDie gemeinsame Beobachtung von Gravitationswellen und Photonen bei der Verschmelzung eines binären Neutronensterns sowie der stichhaltige Hinweis auf einen Blazar als Quelle hochenergetischer Neutrinos im Jahr 2017 trugen wesentlich dazu bei, die Ära der Multi-Messenger-Astronomie einzuläuten. Die Auswirkungen von Echtzeiteffekten der Propagation kosmischer Messenger auf beobachtbare Multi-Messenger-Signaturen werden hergeleitet und mit Hilfe der in dieser Arbeit entwickelten und verbesserten numerischen Tools bestätigt. Darüber hinaus wurde die Plattform Astro-COLIBRI zur Koordinierung von Multi-Messenger-Kampagnen entwickelt, die den Nachweis der am weitesten entfernten aktiven Galaxie mit einem sehr energiereichen Signal im Rahmen dieser Arbeit ermöglichte. Die gewonnenen Erkenntnisse und entwickelte Software tragen zu einer verbesserten Koordination von Multi-Messenger-Kampagnen bei.The joint observation of gravitational waves and the electromagnetic counterparts of a binary neutron star merger and the compelling evidence for a blazar being a source of high-energy neutrino in 2017 ushered in the era of multi-messenger astronomy. The real-time effects of cosmic-messenger propagation on observable multi-messenger signatures are investigated, whose implications are derived and confirmed by numerical tools developed and improved in this thesis. In addition, the holistic platform Astro-COLIBRI has been developed for coordinating multi-messenger campaigns, which facilitated the detection of the most distant active galaxy with a very-high-energy signal conducted within the thesis. The acquired insights and developed tools contribute to improved coordination of multi-messenger campaigns.L'observation conjointe des ondes gravitationnelles et des contreparties électromagnétiques de la fusion d'une étoile à neutrons binaire et l'indice qu'un blazar est une source de neutrino de haute énergie en 2017 ont inauguré l'ère de l'astronomie multi-messagers. Les effets en temps réel de la propagation des messagers cosmiques sur les signatures multi-messagers sont étudiés, dont les implications sont dérivées et confirmées par des outils numériques développés et améliorés dans cette thèse. De plus, la plateforme holistique Astro-COLIBRI a été développée pour coordonner les campagnes multi-messagers, ce qui a facilité la détection d'une galaxie active la plus lointaine avec un signal de très haute énergie réalisée dans le cadre de la thèse. Les connaissances acquises et les outils développés contribuent à une meilleure coordination des campagnes multi-messagers
Prise en compte des effets temporels pour une meilleure coordination des observations multi-messagers
No full textDie gemeinsame Beobachtung von Gravitationswellen und Photonen bei der Verschmelzung eines binären Neutronensterns sowie der stichhaltige Hinweis auf einen Blazar als Quelle hochenergetischer Neutrinos im Jahr 2017 trugen wesentlich dazu bei, die Ära der Multi-Messenger-Astronomie einzuläuten. Die Auswirkungen von Echtzeiteffekten der Propagation kosmischer Messenger auf beobachtbare Multi-Messenger-Signaturen werden hergeleitet und mit Hilfe der in dieser Arbeit entwickelten und verbesserten numerischen Tools bestätigt. Darüber hinaus wurde die Plattform Astro-COLIBRI zur Koordinierung von Multi-Messenger-Kampagnen entwickelt, die den Nachweis der am weitesten entfernten aktiven Galaxie mit einem sehr energiereichen Signal im Rahmen dieser Arbeit ermöglichte. Die gewonnenen Erkenntnisse und entwickelte Software tragen zu einer verbesserten Koordination von Multi-Messenger-Kampagnen bei.The joint observation of gravitational waves and the electromagnetic counterparts of a binary neutron star merger and the compelling evidence for a blazar being a source of high-energy neutrino in 2017 ushered in the era of multi-messenger astronomy. The real-time effects of cosmic-messenger propagation on observable multi-messenger signatures are investigated, whose implications are derived and confirmed by numerical tools developed and improved in this thesis. In addition, the holistic platform Astro-COLIBRI has been developed for coordinating multi-messenger campaigns, which facilitated the detection of the most distant active galaxy with a very-high-energy signal conducted within the thesis. The acquired insights and developed tools contribute to improved coordination of multi-messenger campaigns.L'observation conjointe des ondes gravitationnelles et des contreparties électromagnétiques de la fusion d'une étoile à neutrons binaire et l'indice qu'un blazar est une source de neutrino de haute énergie en 2017 ont inauguré l'ère de l'astronomie multi-messagers. Les effets en temps réel de la propagation des messagers cosmiques sur les signatures multi-messagers sont étudiés, dont les implications sont dérivées et confirmées par des outils numériques développés et améliorés dans cette thèse. De plus, la plateforme holistique Astro-COLIBRI a été développée pour coordonner les campagnes multi-messagers, ce qui a facilité la détection d'une galaxie active la plus lointaine avec un signal de très haute énergie réalisée dans le cadre de la thèse. Les connaissances acquises et les outils développés contribuent à une meilleure coordination des campagnes multi-messagers
Berücksichtigung von Echtzeiteffekten zur besseren Koordination von Multi-Messenger-Kampagnen
No full textL'observation conjointe des ondes gravitationnelles et des contreparties électromagnétiques de la fusion d'une étoile à neutrons binaire et l'indice qu'un blazar est une source de neutrino de haute énergie en 2017 ont inauguré l'ère de l'astronomie multi-messagers. Les effets en temps réel de la propagation des messagers cosmiques sur les signatures multi-messagers sont étudiés, dont les implications sont dérivées et confirmées par des outils numériques développés et améliorés dans cette thèse. De plus, la plateforme holistique Astro-COLIBRI a été développée pour coordonner les campagnes multi-messagers, ce qui a facilité la détection d'une galaxie active la plus lointaine avec un signal de très haute énergie réalisée dans le cadre de la thèse. Les connaissances acquises et les outils développés contribuent à une meilleure coordination des campagnes multi-messagers.The joint observation of gravitational waves and the electromagnetic counterparts of a binary neutron star merger and the compelling evidence for a blazar being a source of high-energy neutrino in 2017 ushered in the era of multi-messenger astronomy. The real-time effects of cosmic-messenger propagation on observable multi-messenger signatures are investigated, whose implications are derived and confirmed by numerical tools developed and improved in this thesis. In addition, the holistic platform Astro-COLIBRI has been developed for coordinating multi-messenger campaigns, which facilitated the detection of the most distant active galaxy with a very-high-energy signal conducted within the thesis. The acquired insights and developed tools contribute to improved coordination of multi-messenger campaigns.Die gemeinsame Beobachtung von Gravitationswellen und Photonen bei der Verschmelzung eines binären Neutronensterns sowie der stichhaltige Hinweis auf einen Blazar als Quelle hochenergetischer Neutrinos im Jahr 2017 trugen wesentlich dazu bei, die Ära der Multi-Messenger-Astronomie einzuläuten. Die Auswirkungen von Echtzeiteffekten der Propagation kosmischer Messenger auf beobachtbare Multi-Messenger-Signaturen werden hergeleitet und mit Hilfe der in dieser Arbeit entwickelten und verbesserten numerischen Tools bestätigt. Darüber hinaus wurde die Plattform Astro-COLIBRI zur Koordinierung von Multi-Messenger-Kampagnen entwickelt, die den Nachweis der am weitesten entfernten aktiven Galaxie mit einem sehr energiereichen Signal im Rahmen dieser Arbeit ermöglichte. Die gewonnenen Erkenntnisse und entwickelte Software tragen zu einer verbesserten Koordination von Multi-Messenger-Kampagnen bei
Consideration of real-time effects for improved coordination of multi-messenger campaigns
No full textDie gemeinsame Beobachtung von Gravitationswellen und Photonen bei der Verschmelzung eines binären Neutronensterns sowie der stichhaltige Hinweis auf einen Blazar als Quelle hochenergetischer Neutrinos im Jahr 2017 trugen wesentlich dazu bei, die Ära der Multi-Messenger-Astronomie einzuläuten. Die Auswirkungen von Echtzeiteffekten der Propagation kosmischer Messenger auf beobachtbare Multi-Messenger-Signaturen werden hergeleitet und mit Hilfe der in dieser Arbeit entwickelten und verbesserten numerischen Tools bestätigt. Darüber hinaus wurde die Plattform Astro-COLIBRI zur Koordinierung von Multi-Messenger-Kampagnen entwickelt, die den Nachweis der am weitesten entfernten aktiven Galaxie mit einem sehr energiereichen Signal im Rahmen dieser Arbeit ermöglichte. Die gewonnenen Erkenntnisse und entwickelte Software tragen zu einer verbesserten Koordination von Multi-Messenger-Kampagnen bei.The joint observation of gravitational waves and the electromagnetic counterparts of a binary neutron star merger and the compelling evidence for a blazar being a source of high-energy neutrino in 2017 ushered in the era of multi-messenger astronomy. The real-time effects of cosmic-messenger propagation on observable multi-messenger signatures are investigated, whose implications are derived and confirmed by numerical tools developed and improved in this thesis. In addition, the holistic platform Astro-COLIBRI has been developed for coordinating multi-messenger campaigns, which facilitated the detection of the most distant active galaxy with a very-high-energy signal conducted within the thesis. The acquired insights and developed tools contribute to improved coordination of multi-messenger campaigns.L'observation conjointe des ondes gravitationnelles et des contreparties électromagnétiques de la fusion d'une étoile à neutrons binaire et l'indice qu'un blazar est une source de neutrino de haute énergie en 2017 ont inauguré l'ère de l'astronomie multi-messagers. Les effets en temps réel de la propagation des messagers cosmiques sur les signatures multi-messagers sont étudiés, dont les implications sont dérivées et confirmées par des outils numériques développés et améliorés dans cette thèse. De plus, la plateforme holistique Astro-COLIBRI a été développée pour coordonner les campagnes multi-messagers, ce qui a facilité la détection d'une galaxie active la plus lointaine avec un signal de très haute énergie réalisée dans le cadre de la thèse. Les connaissances acquises et les outils développés contribuent à une meilleure coordination des campagnes multi-messagers
A Case Study on the Trade-Offs between Security, Scalability, and Efficiency in Smart Home Sensor Networks
No full textThis paper presents the design of a case study that examines the trade-offs between security, scalability and efficiency for sensor networks in IoT environments. Among the trade-offs we will investigate throughput and real-time response for sensor data collected by wireless sensors and transmitted into a scalable Cloud environment for storage and processing. The case study will be performed on a Smart Home prototype system developed at the University of West Florida that functions as a testbed system of a comparable IoT environment. The Smart Home prototype system provides sensor network and sensor data collection and processing services designed to infer activities in a home but it lacks security and scalability of its services. We anticipate that results of the case study will provide generalizable insight into the design of secure and scalable IoT applications.Conference PaperPre-printPermission granted to the University of West Florida to digitize and display this item for non-profit research and educational purposes. Any reuse of this item in excess of fair use or other copyright exemptions requires the permission of the copyright holder
Trade-offs involved in the choice of cloud service configurations when building secure, scalable, and efficient Internet-of-Things networks
No full textThis article focuses on results obtained from two cloud-based models that examine trade-offs between security, scalability, and efficiency of data collection for Internet-of-Things sensor networks. This work can provide insight for Internet-of-Things systems designers in choosing security controls and scalability features when working with cloud services. The results were obtained from a smart home Internet-of-Things prototype system in which data records from in-home sensors are transmitted wirelessly to an in-home hub, which forwards them to a cloud web service for storage and analysis. We consider different configurations and security controls on the wireless (in-home) and on the wired (home-to-web) sides. The configuration on the wireless side includes encrypted or plain-text transmission from the wireless sensors to the in-home hub for probing if software encryption of sensor data adds appreciable delay to the transmission time. The configuration on the wired side includes encryption or plain-text transmission, with or without authentication, with or without scalable cloud services. For each configuration, we measure end-to-end latency, transmission latency, and processing latency at the web service. Results of the experiments on the wired side showed much greater latencies and variability of latencies when using scalable cloud services
Detection of data anomalies at the edge of pervasive IoT systems
No full textValidation of input data is essential in any computer system, but perhaps particularly important in pervasive IoT systems such as smart homes, smart cars, wearable health monitors, etc. In such systems, actions taken based on invalid inputs could have severe consequences. In this paper, we present statistical techniques for identifying data anomalies at the gateway that connects an edge network to its associated cloud services. We address two kinds of anomalies in environmental sensor data: data bias anomalies and sensor cut-off anomalies. In simulation experiments, we evaluate the effectiveness of applying control charts, a statistical process monitoring technique, to both kinds of anomalies. Our results show that using control charts as statistical methods for anomaly detection in IoT systems not only provides high performance in terms of accuracy and power (probability of detecting the anomaly), but also offers a graphical tool to monitor the IoT sensor data.Journal ArticleAuthor's accepted manuscrip
Aircraft interior and seat design: priorities based on passengers’ opinions
No full textComfort is an important factor for passengers in the selection of airlines, and electric propeller aircraft will be an important element of future sustainable aviation. In this paper, we studied the order of importance of different (dis)comfort factors regarding traveling with propeller aircraft. Two experiments were conducted, one was a simulation flight on the ground with 33 participants and the other were two real flights with 97 participants. All participants were asked to rank the importance of different (dis)comfort factors in different phases of flights. Results indicated that though there are differences between the simulation and the real flights, noise, vibration and the seat are among the most important factors regarding discomfort, and space, lighting, temperature and seat are the most important factors of comfort. The results are different to those reported from previous studies on travelling by jet, where anthropometry is the most important factor. This finding suggests a difference in passenger perception between travelling by propeller propulsion and jet engines, and casts new requirements on the aircraft interior and service design for future sustainable aviation.Materials and ManufacturingMechatronic Desig
Astro-COLIBRI: a new platform for real-time multi-messenger astrophysics
No full textFlares of known astronomical sources and new transient phenomena occur on
different timescales, from sub-seconds to several days or weeks. The discovery
potential of both serendipitous observations and multi-messenger and
multi-wavelength follow-up observations could be maximized with a tool which
allows for quickly acquiring an overview over both persistent sources as well
as transient events in the relevant phase space. We here present COincidence
LIBrary for Real-time Inquiry (Astro-COLIBRI), a novel and comprehensive tool
for this task.
Astro-COLIBRI's architecture comprises a RESTful API, a real-time database, a
cloud-based alert system and a website (https://astro-colibri.com) as well as
apps for iOS and Android as clients for users. The structure of Astro-COLIBRI
is optimized for performance and reliability and exploits concepts such as
multi-index database queries, a global content delivery network (CDN), and
direct data streams from the database to the clients. Astro-COLIBRI evaluates
incoming VOEvent messages of astronomical observations in real time, filters
them by user-specified criteria and puts them into their MWL and MM context.
The clients provide a graphical representation with an easy to grasp summary of
the relevant data to allow for the fast identification of interesting phenomena
and provides an assessment of observing conditions at a large selection of
observatories around the world.
We here summarize the key features of Astro-COLIBRI, the architecture and
used data resources. We specifically provide examples for applications and use
cases. Focussing on the high-energy domain, we showcase how Astro-COLIBRI
facilitates the search for high-energy gamma-ray counterparts to high-energy
neutrinos and scheduling of follow-up observations of a large variety of
transient phenomena like gamma-ray bursts, gravitational waves, TDEs, FRBs, and
others.Comment: Proceedings of the 37th International Cosmic Ray Conference (ICRC
2021
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