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- Ahuja, Bhawna, et al.
(författare)
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Novel QoS-Aware Physical Layer Security Analysis Considering Random Inter-node Distances
- 2019
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Ingår i: ICC 2019 - 2019 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS (ICC). - : IEEE. - 9781538680889 - 9781538680896
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Konferensbidrag (refereegranskat)abstract
- Physical layer security (PLS) in wireless communication has gained recent attention due to the emergence of new technological breakthroughs in this space. Since the internode distances have been noted to play a key role in the desired security performance, we propose a novel quality-of-service-aware PLS model that incorporates the random spatial deployment of the legitimate users and a potential attacker. This proposed model considers practical constraints like maximum separation between legitimate users and eavesdropping capability of attacker. In this regard, a novel concept of eavesdropping zone is also introduced. Eventually, closed-form expressions are derived for secrecy outage probability using the probabilistic inter-node distance distributions between the legitimate users and attacker to shed key analytical insights like optimal parameter designing to achieve a desired secrecy performance. Lastly, specific simulation results, presented to validate the analytical claims and provide key secured system designing perspectives, corroborate the potential of the proposed framework for more accurately characterizing the desired PLS performance from both the legitimate users and attackers point-of-view.
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- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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- Callejas, Ileana A., et al.
(författare)
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Effect of COVID-19 Anthropause on Water Clarity in the Belize Coastal Lagoon
- 2021
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Ingår i: Frontiers in Marine Science. - : Frontiers Media SA. - 2296-7745. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- The Coronavirus disease 2019 (COVID-19) pandemic halted human activities globally in multiple sectors including tourism. As a result, nations with heavy tourism, such as Belize, experienced improvements in water quality. Remote sensing technologies can detect impacts of “anthropauses” on coastal water quality. In this study, moderate resolution imaging spectroradiometer (MODIS) satellite data were employed along the Belizean coast to investigate impacts of the COVID-19 shutdown on water quality. The attenuation coefficient at 490 nm, Kd(490), was used as an indicator of water quality, with a lower Kd(490) indicating increased water clarity. Four Coastal Management Zones were characterized by marine traffic as high traffic areas (HTAs) and two as low traffic areas (LTAs). Monthly composites for two periods, 2002–2019 (baseline) and 2020 were examined for Kd(490). For months prior to the COVID-19 shutdown in Belize, there was generally no significant difference in Kd(490) (p > 0.05) between 2020 and baseline period in HTAs and LTAs. Through the shutdown, Kd was lower in 2020 at HTAs, but not for LTAs. At the LTAs, the Kd(490)s observed in 2020 were similar to previous years through October. In November, an unusually active hurricane season in 2020 was associated with decreased water clarity along the entire coast of Belize. This study provides proof of concept that satellite-based monitoring of water quality can complement in situ data and provide evidence of significant water quality improvements due to the COVID-19 shutdown, likely due to reduced marine traffic. However, these improvements were no longer observed following an active hurricane season.
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- De, Swades, et al.
(författare)
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Stochastic Solar Harvesting Characterization for Sustainable Sensor Node Operation
- 2019
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Ingår i: IET Wireless Sensor Systems. - : Institution of Engineering and Technology (IET). - 2043-6386 .- 2043-6394. ; 9:4, s. 208-217
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Tidskriftsartikel (refereegranskat)abstract
- Self-sustainability of low power wireless sensor nodes is the need of the hour to realize ubiquitous wireless networks. To address this requirement we investigate the practical feasibility of sustainable green sensor network with solar-powered nodes. We propose simple yet efficient (i) analytical circuit model for solar panel assisted supercapacitor charging and (ii) statistical model for characterizing the solar intensity distribution. Combining these circuit and statistical models, we derive a novel solar charging rate distribution for the solar-powered supercapacitor. To gain analytical insights, we also propose an ideal diode based tight approximation for the practical supercapacitor charging circuit model. The accuracy of these proposed analytical models have been validated by extensive numerical simulations based on the real-world data, i.e., solar intensity profile and solar panel characteristics. The derived solar charging rate distribution is used to investigate the supported sampling rate of the node with different varying number of on-board sensors for a given energy outage probability. Results suggest that for an energy outage probability of 0.1, at New Delhi, a 40 F supercapacitor and a 3 W solar panel can support the operation of Waspmote with 6 on-board toxic gas sensors with a sampling rate of 65 samples per day. Further, we use the proposed models to estimate the practical supercapacitor and solar panel sizes required to ensure sustainability of sensor node operation at different geographical locations with varying sensing rate.
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- Gupta, Isha, et al.
(författare)
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Triple Bottom Line : Evidence from aviation sector
- 2020
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Ingår i: International Journal of Business Ethics and Governance. - Istanbul, Turkey : EuroMid Academy of Business & Technology (EMABT). - 2717-9923. ; , s. 71-80
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The COVID-19 has spread with alarming speed bringing the global economy to a stand-still. As countries have imposed tight restrictions, the aviation industry is severely hit and its revenues sorely plummeted. The study aims to analyze the impact of Covid-19 on the aviation industry. Its main purpose is to alleviate the pandemic effect by applying the Triple Bottom Line (TBL) approach. TBL mainly addresses sustainability and focuses on three dimensions: people, planet, and performance. The aviation industry can sustain its revenues by adopting disruptive and innovative strategies that can counteract pollution effect (planet scale). Furthermore, it should urgently integrate artificial intelligence and machine learning in its booking system (people scale) to compensate for ongoing travel cancellations, delay, and headcounts reduction. To regain customers’ confidence, and boost its performance, the aviation industry should apply innovative plans such as electronic waivers, free cancellation, no-fee itinerary change.
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- Gupta, Nishant, et al.
(författare)
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Trajectory and Resource Allocation for UAV Replacement to Provide Uninterrupted Service
- 2023
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Ingår i: IEEE Transactions on Communications. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 0090-6778 .- 1558-0857. ; 71:12, s. 7288-7302
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Tidskriftsartikel (refereegranskat)abstract
- Unmanned aerial vehicles (UAVs) have emerged as a specular technology that can assist the terrestrial base stations. However, the battery limitation of UAV inhibits the system performance by decreasing the overall lifespan of coverage provided by the UAV, driving the necessity of replacement and recharging. Thus, the energy-depleted UAV must be returned to a charging station and be replaced by a fully charged UAV to increase the service span. Therefore, this paper presents a novel framework of UAV replacement to maintain coverage continuity in a UAV-assisted wireless communication system when a serving UAV runs out of energy. Our objective during this replacement process is to maximize the minimum achievable throughput to the UAV-served ground users by jointly optimizing the three-dimensional (3D) multi-UAV trajectory and resources allocated to the users from the individual UAVs. The formulated problem is non-convex for which an efficient algorithm based on successive convex approximation and alternating optimization is proposed. Numerical results provide insights into the UAV trajectories and the effectiveness of the proposed scheme compared to the existing benchmark schemes.
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- Kaushik, K., et al.
(författare)
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Experimental demonstration of multi-hop RF energy transfer
- 2013
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Ingår i: 2013 IEEE 24th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781467362351 ; , s. 538-542
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Konferensbidrag (refereegranskat)abstract
- Batteries of field nodes in a wireless sensor network pose an upper limit on the network lifetime. Energy harvesting and harvesting aware medium access control protocols have the potential to provide uninterrupted network operation, as they aim to replenish the lost energy so that energy neutral operation of the energy harvesting nodes can be achieved. To further improve the energy harvesting process, there is a need for novel schemes so that maximum energy is harvested in a minimum possible time. Multi-hop radio frequency (RF) energy transfer is one such solution that addresses these needs. With the optimal placement of energy relay nodes, multi-hop RF energy transfer can save energy of the source as well as time for the harvesting process. In this work we experimentally demonstrate multi-hop RF energy transfer, wherein two-hop energy transfer is shown to achieve significant energy and time savings with respect to the single-hop case. It is also shown that the gain obtained can be translated to energy transfer range extension.
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