| 1. |
- AL-Naday, Mays, et al.
(författare)
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Service-based Federated Deep Reinforcement Learning for Anomaly Detection in Fog Ecosystems
- 2023
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Ingår i: 2023 26th Conference on Innovation in Clouds, Internet and Networks and Workshops (ICIN). - : Institute of Electrical and Electronics Engineers (IEEE). - 9798350398045 - 9798350398052 ; , s. 121-128
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Konferensbidrag (refereegranskat)abstract
- With Digital transformation, the diversity of services and infrastructure in backhaul fog network(s) is rising to unprecedented levels. This is causing a rising threat of a wider range of cyber attacks coupled with a growing integration of constrained range of infrastructure, particularly seen at the network edge. Deep reinforcement-based learning is an attractive approach to detecting attacks, as it allows less dependency on labeled data with better ability to classify different attacks. However, current approaches to learning are known to be computationally expensive (cost) and the learning experience can be negatively impacted by the presence of outliers and noise (quality). This work tackles both the cost and quality challenges with a novel service-based federated deep reinforcement learning solution, enabling anomaly detection and attack classification at a reduced data cost and with better quality. The federated settings in the proposed approach enable multiple edge units to create clusters that follow a bottom-up learning approach. The proposed solution adapts deep Q-learning Network (DQN) for service-tunable flow classification, and introduces a novel federated DQN (FDQN) for federated learning. Through such targeted training and validation, variation in data patterns and noise is reduced. This leads to improved performance per service with lower training cost. Performance and cost of the solution, along with sensitivity to exploration parameters are evaluated using an example publicly available dataset (UNSW-NB15). Evaluation results show the proposed solution to maintain detection accuracy with lower data supply, while improving the classification rate by a factor of ≈ 2.
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| 2. |
- Al Naggar, Yahya, et al.
(författare)
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Are Honey Bees at Risk from Microplastics?
- 2021
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Ingår i: Toxics. - : MDPI AG. - 2305-6304. ; 9:5
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Tidskriftsartikel (refereegranskat)abstract
- Microplastics (MPs) are ubiquitous and persistent pollutants, and have been detected in a wide variety of media, from soils to aquatic systems. MPs, consisting primarily of polyethylene, polypropylene, and polyacrylamide polymers, have recently been found in 12% of samples of honey collected in Ecuador. Recently, MPs have also been identified in honey bees collected from apiaries in Copenhagen, Denmark, as well as nearby semiurban and rural areas. Given these documented exposures, assessment of their effects is critical for understanding the risks of MP exposure to honey bees. Exposure to polystyrene (PS)-MPs decreased diversity of the honey bee gut microbiota, followed by changes in gene expression related to oxidative damage, detoxification, and immunity. As a result, the aim of this perspective was to investigate whether wide-spread prevalence of MPs might have unintended negative effects on health and fitness of honey bees, as well as to draw the scientific community's attention to the possible risks of MPs to the fitness of honey bees. Several research questions must be answered before MPs can be considered a potential threat to bees.
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| 3. |
- Al Naggar, Yahya, et al.
(författare)
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Chronic Exposure to Polystyrene Microplastic Fragments Has No Effect on Honey Bee Survival, but Reduces Feeding Rate and Body Weight
- 2023
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Ingår i: Toxics. - : MDPI. - 2305-6304. ; 11:2
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Tidskriftsartikel (refereegranskat)abstract
- Microplastics (MPs), in the form of fragments and fibers, were recently found in honey samples collected in Ecuador as well as in honey bees collected from Denmark and China. However, little is known about how MPs impact bee health. To fill this knowledge gap, we investigated the potential toxicity of irregularly shaped polystyrene (PS)-MP fragments on honey bee health. In the first experiment of its kind with honey bees, we chronically exposed bees with a well-established gut microbiome to small (27 ± 17 µm) or large (93 ± 25 µm) PS-MP fragments at varying concentrations (1, 10, 100 µg mL−1) for 14 days. Bee mortality, food consumption, and body weight were all studied. We found that chronic exposure to PS-MP fragments has no effect on honey bee survival, but reduced the feeding rate and body weight, particularly at 10 µg PS-MP fragments per mL, which may have long-term consequences for honey bee health. The findings of this study could assist in the risk assessment of MPs on pollinator health.
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| 4. |
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| 5. |
- Al Nahas, Beshr, 1985, et al.
(författare)
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Competition: Towards Low-Power Wireless Networking that Survives Interference with Minimal Latency
- 2017
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Ingår i: International Conference on Embedded Wireless Systems and Networks. - 2562-2331. ; 2017, s. 268-269
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Konferensbidrag (refereegranskat)abstract
- Low-power wireless networking needs to survive interference in order to accommodate the requirements of serious applications of Internet of Things. Synchronous transmission techniques like Glossy and Chaos perform well under normal operating conditions. However, their data delivery latency suffers under interference even when extended to use channel hopping. In this paper we discuss our techniques to enhance the robustness of synchronous flooding while keeping the latency and power consumption minimal.
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| 6. |
- Al Nahas, Beshr, 1985, et al.
(författare)
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Concurrent Transmissions for Multi-hop Bluetooth 5
- 2019
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Ingår i: International Conference on Embedded Wireless Systems and Networks. - 2562-2331. ; , s. 130-141
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Konferensbidrag (refereegranskat)abstract
- Bluetooth is an omnipresent communication technology, available on billions of connected devices today. While it has been traditionally limited to peer-to-peer and star network topology, the recent Bluetooth 5 standard introduces new operating modes to allow for increased reliability and Bluetooth Mesh supports multi-hop networking based on message flooding. In this paper, we present BlueFlood. It adapts concurrent transmissions, as introduced by Glossy, to Bluetooth. The result is fast and efficient network-wide data dissemination in multi-hop Bluetooth networks. Moreover, we show that BlueFlood floods can be reliably received by off-the-shelf Bluetooth devices such as smart phones, opening new applications of concurrent transmissions and seamless integration with existing technologies. We present an in-depth experimental feasibility study of concurrent transmissions over Bluetooth PHY in a controlled environment. Further, we build a small-scale testbed where we evaluate BlueFlood in real-world settings of a residential environment. We show that BlueFlood achieves 99% end-to-end delivery ratio in multi-hop networks with a duty cycle of 0.13% for 1-second intervals.
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| 7. |
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| 8. |
- Antonini, G., et al.
(författare)
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PEEC modeling of automotive electromagnetic problems
- 2008
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Ingår i: Applied Computational Electromagnetics Society Newsletter. - 1056-9170. ; 23:1, s. 39-50
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents the combination of the nonorthogonal Partial Element Equivalent Circuit (PEEC) models and interconnect structures through a macromodel approach for the analysis of automotive electromagnetic problems. The applications are within automotive computational electromagnetics due to the typical combination of cable harnesses and chassis structures. It is shown that PEEC-based solvers are capable of handling electrically large problems with high geometrical complexity for detailed analysis in both the time- and frequency- domain with attached multi-conductor transmission lines.
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| 9. |
- Berger, Cyrille, 1982-, et al.
(författare)
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Evaluation of Reactive Obstacle Avoidance Algorithms for a Quadcopter
- 2016
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Ingår i: Proceedings of the 14th International Conference on Control, Automation, Robotics and Vision 2016 (ICARCV). - : IEEE conference proceedings. - 9781509035496 - 9781509047574 - 9781509035502
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Konferensbidrag (refereegranskat)abstract
- In this work we are investigating reactive avoidance techniques which can be used on board of a small quadcopter and which do not require absolute localisation. We propose a local map representation which can be updated with proprioceptive sensors. The local map is centred around the robot and uses spherical coordinates to represent a point cloud. The local map is updated using a depth sensor, the Inertial Measurement Unit and a registration algorithm. We propose an extension of the Dynamic Window Approach to compute a velocity vector based on the current local map. We propose to use an OctoMap structure to compute a 2-pass A* which provide a path which is converted to a velocity vector. Both approaches are reactive as they only make use of local information. The algorithms were evaluated in a simulator which offers a realistic environment, both in terms of control and sensors. The results obtained were also validated by running the algorithms on a real platform.
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| 10. |
- Boalt, Elin, 1976-
(författare)
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Ecology and evolution of tolerance in two cruciferous species
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Tolerance to herbivory is the ability of plants to maintain fitness in spite of damage. The goal of this thesis is to investigate the genetic variation and expression of tolerance within species, determine whether and in what conditions tolerance has negative side-effects, and how tolerance is affected by different ecological factors. Tolerance is investigated with special focus on the effects of different damage types, competitive regimes, history of herbivory, and polyploidization in plants. Studies are conducted as a literature review and three experiments on two cruciferous species Raphanus raphanistrum and Cardamine pratensis.In the tolerance experiments, plants are subjected to artificial damage solely, or in a combination with natural damage. A literature review was conducted in order to investigate the effects of damage method. We found that traits related to tolerance, such as growth and fitness were not as sensitive in regard to damage method as measures of induced chemical traits, or measures of secondary herbivory.Genetic variation of tolerance was demonstrated within populations of R. raphanistrum and between subspecies of C. pratensis. In R. raphanistrum, traits involved in floral display and male fitness were positively associated with plant tolerance to herbivore damage. A potential cost of tolerance was demonstrated as a negative correlation between levels of tolerance in high and low competitive regimes. I found no evidence of other proposed costs of tolerance in terms of highly tolerant plants suffering of reduced fitness in the absence of herbivores or trade-offs in terms of a negative association between tolerance to apical and leaf damage, or between tolerance and competitive ability. In C. pratensis, higher ploidy level in plants involved higher levels of tolerance measured as clonal reproduction. Furthermore, populations exposed to higher levels of herbivory had better tolerance than populations exposed to lower levels of herbivory. In this thesis, I demonstrate evidence of different components for the evolution of tolerance in plants: genotypic variation, selective factors in terms of costs and ploidization, and selective agents in terms of changing environment or herbivore pressure.
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