1,721,057 research outputs found
Advanced Constellation Emulation and Synthetic Datasets Generation for Non-Terrestrial Networks
No full textMega satellite constellations, now realized entities, encompass thousands of nodes. However, efficient orchestration of multi-hop paths and distributed processing tasks in Non-Terrestrial Networks (NTN) remains a considerable challenge. The integration of NTN systems into 5G cellular networks necessitates innovative adaptations of Software-Defined Networking (SDN) and Multi-access Edge Computing (MEC) to suit the dynamic environments of NTN. In this context, we present MeteorNet, a state-of-the-art emulation tool conceived for satellite constellations. MeteorNet accurately replicates the behavior of NTNs by implementing space orbits, Earth rotation calculations, and Linux network interfaces across diverse network layers. Coupled with a continuous measurement system founded on sFlow, MeteorNet compiles critical switch variables in a centralized database, thus providing a distinctive methodology for creating realistic synthetic datasets. The pertinence of synthetic datasets is paramount in NTN, given the scarcity of operative systems and the inaccessibility of accurate data from the few existing systems due to proprietary constraints. These datasets are instrumental for formulating and training intelligent control algorithms and Machine Learning (ML) models for SDN and MEC advancements in NTN. To illustrate the efficacy of this approach, we explore a realistic networking case study with a ring topology, demonstrating how data models describe intricate routing and edge computing protocols for NTN
Fuzzy Logic-Based Orchestration of Multi-Access Edge Computing in LEO Satellite Constellations
No full textIn the fast-evolving domain of satellite communications, massive constellations of LEO satellites are increasingly gaining notice in both academic and industrial sectors. Operating these growing constellations has become a complex challenge, and new obstacles have emerged with integrating cellular networks in the space sector. Some techniques like Multi-access Edge Computing (MEC) were initially designed for static terrestrial networks and should be adapted to the dynamic nature of Non-Terrestrial Networks (NTN). This study introduces an innovative Fuzzy Logic-based controller tailored explicitly for determining the operational status of satellite MEC servers based on historical task loads and task processing failures. Our approach is grounded in a distributed control framework, where each satellite node operates autonomously relying on its own data and limited information from neighboring nodes. We evaluated our fuzzy controller against a baseline strategy, demonstrating significant improvements in reducing the overall active time of MEC nodes. The orchestration effectiveness of these strategies was tested by using our custom-built continuous time emulation framework for satellite constellations. This framework integrates 1) the Simplified General Perturbations Model 4 (SGP4) for orbit propagation, 2) Mininet for network virtualization, 3) Docker for operating system virtualization, and 4) MEC task offloading and orchestration
From Emerging LEO Satellite Constellations to the Space Cloud: Emulation Platforms and Orchestration Methods
No full textIn the rapidly advancing field of satellite communications, mega-constellations of Low Earth Orbit (LEO) satellites are gaining significant attention from the academic and industrial sectors. Managing these expanding constellations has become increasingly complex, and integrating them with classical cellular networks presents new automation challenges. We envision a Space Cloud in which Multiaccess Edge Computing (MEC) services are deployed within cross-liked space networks to address emerging Non-Terrestrial Networks (NTNs) latency demands. Integrating computation services in orbit will be instrumental in unlocking a Space Cloud that reduces the need to route computation requests to the Internet backbone. This study’s first contribution is MeteorNet, an open-source constellation and edge computing emulation platform aimed at assessing the expected performance of future Space Clouds. MeteorNet realistically replicates the behavior of edge computing in a synthetic satellite constellation network hosting onboard containerized servers. The second contribution comprises two innovative edge orchestration strategies based on fuzzy logic and reinforcement learning.
These strategies leverage historical data on task loads and processing failures to control the activation of on-orbit edge servers, ensuring efficient resource utilization. A Pareto-efficient analysis of multiple Key Performance Indicators (KPIs) using MeteorNet proves the approach’s feasibility in space missions with energy constraints and limited computation resources
On the Latency Trade-off Between Space and Terrestrial Clouds in Non-Terrestrial Networks
No full textNon-Terrestrial Networks (NTN) are poised to revolutionize 5G and 6G networks by integrating terrestrial and space-based cloud systems, enabling dynamic task allocation for optimal performance. Despite their promise, understanding the trade-offs between terrestrial and non-terrestrial edge computing architectures remains an area for improvement. This paper presents a comprehensive latency-focused trade-off analysis using a novel real-time emulation platform that accurately models terrestrial and space cloud environments. By evaluating network latency across geodesic distances from a fixed ground gateway, we delineate scenarios where terrestrial clouds excel and identify conditions under which Space Cloud architectures surpass their terrestrial counterparts. Additionally, we analyze how server placement strategies in satellite constellations impact performance, revealing the critical interplay between server distribution and latency outcomes. These findings offer actionable insights for designing and operating hybrid cloud systems, emphasizing the need for tailored architectures to maximize the potential of NTN-based edge computing
A segmented architecture approach to provide a continuous, Long-term, adaptive and cost-effective glaciers monitoring system based on DTN communications and cubesat platforms
Full text linkFil: Barrientos, Carlos. Comisión Nacional de Actividades Espaciales; ArgentinaFil: Ferral, Anabella. Comisión Nacional de Actividades Espaciales; ArgentinaFil: Cara, Leandro. Comisión Nacional de Actividades Espaciales; ArgentinaFil: Fraire, Juan A. Université Grenoble-Alpes, INPG, TIMA Laboratoires, Grenoble; Francia.Fil: Fraire, Juan A. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Velazco, Raoul. Université Grenoble-Alpes, INPG, TIMA Laboratoires, Grenoble; Francia.Fil: Madoery, Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Ferreyra, Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Mountain glaciers are important because they work as precipitation buffers andwater sources for downstream populations. In addition, they have been a source of data forclimate dynamics analysis. Measuring glaciers meteorological variables, estimating theamount of black carbon, as well as recording mass slides on a periodic basis becomesmandatory to understand and drive effective environmental policies. While thesemeasurements are traditionally executed via expensive field campaigns, they tend to bescarce and non-periodic. Thus, remote sensing alternatives have been explored by thecommunity, they are based in monolithic satellite architectures which besides the longdevelopment time, are bounded in mission lifetime. In this paper we propose a GlacierSegmented Observation System (SOS), based on a number of interconnected cubesatsunder the segmented architecture paradigm to provide frequent revisit times and extendablelifetime for critical observation missions. We evaluate how SOS can support a world-wideglacier remote sensing mission to then discuss relevant mission requirements, formationflying disposition of satellites and communication architecture challengesFil: Barrientos, Carlos. Comisión Nacional de Actividades Espaciales; ArgentinaFil: Ferral, Anabella. Comisión Nacional de Actividades Espaciales; ArgentinaFil: Cara, Leandro. Comisión Nacional de Actividades Espaciales; ArgentinaFil: Fraire, Juan A. Université Grenoble-Alpes, INPG, TIMA Laboratoires, Grenoble; Francia.Fil: Fraire, Juan A. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Velazco, Raoul. Université Grenoble-Alpes, INPG, TIMA Laboratoires, Grenoble; Francia.Fil: Madoery, Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Ferreyra, Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Ingeniería de Sistemas y Comunicacione
Empowering the Tracking Performance of LEO PNT by Means of Meta-Signals
Full text linkGlobal Navigation Satellite Systems (GNSSs) are by far the most widespread technology for Position Navigation and Timing (PNT). They have been traditionally deployed exploiting Medium Earth Orbit (MEO) or Geostationary Earth Orbit (GEO) satellite constellations. To meet future demands and overcome MEO and GEO limitations, GNSSs based on Low Earth Orbit (LEO) constellations have been investigated as a radical system change. Although characterized by a higher Doppler effect, a PNT service supplied by means of LEO satellites can provide received signals that are about 30 dB stronger. Moreover, existing LEO constellations and the forthcoming mega-constellations, which are designed for broadband internet coverage, can be exploited to provide a piggybacked PNT service. With this cost-effective solution, a secondary PNT service might be subject to an economical use of resources, which may result in substantial bandwidth limitations. At the same time, the introduction of meta-signals in the GNSS literature has brought a new receiver signal processing strategy, particularly effective in terms of available bandwidth exploitation. It allows to increase the positioning accuracy exploiting a wideband processing approach, which might be challenging under severe Doppler conditions. A narrowband implementation of the meta-signal concept, namely Virtual Wideband (VWB) can tolerate harsh Doppler conditions while also reducing the processed bandwidth. It is thus more effective when addressing a secondary PNT service, where a limited frequency occupation might be an essential requirement. The aim of this work is to show the applicability of a VWB receiver architecture on signals provided by a piggybacked PNT service, hosted on a broadband LEO constellation. We demonstrate the capability of this implementation to bear high Doppler conditions while empowering the potential of LEO PNT
COVID‑19 mitigation by digital contact tracing and contact prevention (app‑based social exposure warnings)
Full text linkFil: Soldano, Germán J. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas; Argentina.Fil: Soldano, Germán J. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentina.Fil: Fraire Juan A. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.Fil: Fraire Juan A. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Estudios Avanzados en ingeniería y Tecnología; Argentina.Fil: Fraire Juan A. Saarland University. Saarland Informatics Campus; Saarbrücken, Germany.Fil: Finochietto, Jorge M. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.Fil: Finochietto, Jorge M. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Estudios Avanzados en ingeniería y Tecnología; Argentina.Fil: Quiroga; Rodrigo. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas; Argentina.Fil: Quiroga; Rodrigo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentina.A plethora of measures are being combined in the attempt to reduce SARS-CoV-2 spread. Due to its sustainability, contact tracing is one of the most frequently applied interventions worldwide, albeit with mixed results. We evaluate the performance of digital contact tracing for different infection detection rates and response time delays. We also introduce and analyze a novel strategy we call contact prevention, which emits high exposure warnings to smartphone users according to Bluetooth-based contact counting. We model the effect of both strategies on transmission dynamics in SERIA, an agent-based simulation platform that implements population-dependent statistical distributions. Results show that contact prevention remains effective in scenarios with high diagnostic/response time delays and low infection detection rates, which greatly impair the effect of traditional contact tracing strategies. Contact prevention could play a significant role in pandemic mitigation, especially in developing countries where diagnostic and tracing capabilities are inadequate. Contact prevention could thus sustainably reduce the propagation of respiratory viruses while relying on available technology, respecting data privacy, and most importantly, promoting community-based awareness and social responsibility. Depending on infection detection and app adoption rates, applying a combination of digital contact tracing and contact prevention could reduce pandemic-related mortality by 20–56%.publishedVersionFil: Soldano, Germán J. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas; Argentina.Fil: Soldano, Germán J. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentina.Fil: Fraire Juan A. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.Fil: Fraire Juan A. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Estudios Avanzados en ingeniería y Tecnología; Argentina.Fil: Fraire Juan A. Saarland University. Saarland Informatics Campus; Saarbrücken, Germany.Fil: Finochietto, Jorge M. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.Fil: Finochietto, Jorge M. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Estudios Avanzados en ingeniería y Tecnología; Argentina.Fil: Quiroga; Rodrigo. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas; Argentina.Fil: Quiroga; Rodrigo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentina
Sparse Satellite Constellation Design for LoRa-based Direct-to-Satellite Internet of Things
Full text linkA global Internet of Things is possible by embracing
constellations of satellites acting as orbiting gateways in a Directto-
Satellite IoT (DtS-IoT). By removing the dependency on
ground gateways, DtS-IoT enables a direct service on the regions
illuminated by the passing-by satellite. After an in-depth overview
of relevant experiments and candidate technologies, we discover
that specific configurations of the Long-Range (LoRa) network
protocol specification are particularly appealing to realize the
DtS-IoT vision. Specifically, we profit from the maximum clock
drift permitted on LoRa devices to propose the sparse satellite
constellations concept. This approach significantly reduces the
in-orbit DtS-IoT infrastructure at the expense of latency anyway
present in resource-constrained IoT networks. We then introduce
a novel algorithm comprising specific heuristics to design quasioptimal
topologies for sparse IoT constellations. Obtained results
show that LoRa-compatible DtS-IoT services can already be
provided world-wide with 10% and 4% of the satellites required
for a traditional dense constellation, in different configurations
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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