125 research outputs found
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Grid flexibility by electrifying energy systems for sustainable aviation
This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University LondonDecarbonisation of aviation goals set by Flightpath 2050 Europe’s Vision for Aviation
requires that the airports become emission-free by 2050. This thesis original contribution to
knowledge is to explore the incorporation of aviation electrification technologies, including
electric aircraft (EA), electrified ground support equipment (GSE), and airport parking electric
vehicles (EVs), into power systems, evaluating their influence on grid infrastructure and
operations, as well as their potential to support the grid operation.
A comprehensive review of aviation electrification technologies revealed a research gap in the
integration of these technologies into the power systems. The thesis contributes to electricity
network infrastructure planning for electrification of aviation and airport-based distributed
energy resources (DER) that provide ancillary services to the power grid.
A multi-objective airport microgrid planning framework is developed, comparing EA charging
strategies and revealing that battery swap performs better. Vehicle-to-grid (V2G) strategy with
parking EVs improves the microgrid's performance. A techno-economic assessment of wireless charging
systems for electric airport shuttle buses shows better economic performance than conventional
buses and other charging options.
A novel Aviation-to-Grid (A2G) flexibility concept provides frequency response services to the GB
power system using EA battery charging systems, with typical A2G service capacity showing
significant variation across eight UK airports. A deep reinforcement learning (DRL)-based A2G
dispatch approach evaluates the impact of EA charger capacity on energy dispatch results, with
higher capacities leading to higher revenue and lower operation costs.
To summarise, this thesis addresses the research gaps in integrating aviation
electrification technologies into power systems, offering valuable insights for airport operators
aiming to decarbonise air transport activities through the adoption of these technologies. The
study also provides an understanding of the impacts on grid operators in terms of infrastructure
planning and operations. This comprehensive approach ensures a cohesive understanding of the
challenges and opportunities presented by aviation
electrification and its integration into power systems
Computing Optimal Mixed Strategies for Terrorist Plot Detection Games with the Consideration of Information Leakage
The terrorist’s coordinated attack is becoming an increasing threat to western countries. By monitoring potential terrorists, security agencies are able to detect and destroy terrorist plots at their planning stage. Therefore, an optimal monitoring strategy for the domestic security agency becomes necessary. However, previous study about monitoring strategy generation fails to consider the information leakage, due to hackers and insider threat. Such leakage events may lead to failure of watching potential terrorists and destroying the plot, and cause a huge risk to public security. This paper makes two major contributions. Firstly, we develop a new Stackelberg game model for the security agency to generate optimal monitoring strategy with the consideration of information leakage. Secondly, we provide a double-oracle framework DO-TPDIL for calculation effectively. The experimental result shows that our approach can obtain robust strategies against information leakage with high feasibility and efficiency
MemDA: Forecasting Urban Time Series with Memory-based Drift Adaptation
Urban time series data forecasting featuring significant contributions to
sustainable development is widely studied as an essential task of the smart
city. However, with the dramatic and rapid changes in the world environment,
the assumption that data obey Independent Identically Distribution is
undermined by the subsequent changes in data distribution, known as concept
drift, leading to weak replicability and transferability of the model over
unseen data. To address the issue, previous approaches typically retrain the
model, forcing it to fit the most recent observed data. However, retraining is
problematic in that it leads to model lag, consumption of resources, and model
re-invalidation, causing the drift problem to be not well solved in realistic
scenarios. In this study, we propose a new urban time series prediction model
for the concept drift problem, which encodes the drift by considering the
periodicity in the data and makes on-the-fly adjustments to the model based on
the drift using a meta-dynamic network. Experiments on real-world datasets show
that our design significantly outperforms state-of-the-art methods and can be
well generalized to existing prediction backbones by reducing their sensitivity
to distribution changes.Comment: Accepted by CIKM 202
Techno-economic assessment of wireless charging systems for airport electric shuttle buses
Flightpath 2050, the European Commission's vision for aviation, requires that the aviation industry achieves a 75 % reduction in CO2 emissions per passenger mile and airports become emission-free by 2050. Airport shuttle buses in the airfields are going to be electrified to reduce ground emissions. Simultaneously, the airfield movement space and time schedules are becoming more limited for adopting stationary charging facilities for electrified ground vehicles. Therefore, the dynamic wireless charging technology becomes a promising technology to help improve the stability of electrification of the airfield transport network. This paper proposes a techno-economic assessment of wireless charging, wired charging, and conventional technologies for electrifying airport shuttle buses. A bi-level planning optimisation approach combines the multi-objective Non-dominated Sorting Genetic Algorithm (NSGA-III) and mixed integer linear programming (MILP) algorithm to handle a large number of decision variables and constraints generated from the investigated problem. The airport shuttle bus transport is simulated through a multi-agent-based model (MABM) approach. Four case studies are analysed for illustrating the techno-economic feasibility of wireless charging technology for airport electric shuttle buses. The results show that the wireless charging technology enables the electric shuttle buses to carry smaller batteries while conducting the same as tasks conventional diesel/petrol vehicles and the bi-directional wireless charging technology could help mitigate the impact of electrification of shuttle buses on the distribution network.Engineering and Physical Sciences Research Council (EPSRC): EP/S032053/
Oocytes Selected Using BCB Staining Enhance Nuclear Reprogramming and the In Vivo Development of SCNT Embryos in Cattle
The selection of good quality oocytes is crucial for in vitro fertilization and somatic cloning. Brilliant cresyl blue (BCB) staining has been used for selection of oocytes from several mammalian species. However, the effects of differential oocyte selection by BCB staining on nuclear reprogramming and in vivo development of SCNT embryos are not well understood. Immature compact cumulus–oocyte complexes (COCs) were divided into control (not exposed to BCB), BCB+ (blue cytoplasm) and BCB− (colorless cytoplasm) groups. We found that BCB+ oocytes yielded a significantly higher somatic cell nuclear transfer (SCNT) blastocyst rate and full term development rate of bovine SCNT embryos than the BCB− and control oocytes. BCB+ embryos (embryos developed from BCB+ oocytes) showed increased acetylation levels of histone H3 at K9 and K18 (AcH3K9, AcH3K18), and methylation levels of histone H3 at K4 (H3K4me2) than BCB− embryos (embryos developed from BCB− oocytes) at the two-cell stage. Furthermore, BCB+ embryos generated more total cells, trophectoderm (TE) cells, and inner cell mass (ICM) cells, and fewer apoptotic cells than BCB− embryos. The expression of SOX2, CDX2, and anti-apoptotic microRNA-21 were up-regulated in the BCB+ blastocysts compared with BCB− blastocysts, whereas the expression of pro-apoptotic gene Bax was down-regulated in BCB+ blastocysts. These results strongly suggest that BCB+ oocytes have a higher nuclear reprogramming capacity, and that BCB staining can be used to select developmentally competent oocytes for nuclear transfer
SC1 Promotes MiR124-3p Expression to Maintain the Self-Renewal of Mouse Embryonic Stem Cells by Inhibiting the MEK/ERK Pathway
First attempt of directionality reconstruction for atmospheric neutrinos in a large homogeneous liquid scintillator detector
The directionality information of incoming neutrinos is essential to
atmospheric neutrino oscillation analysis since it is directly related to the
oscillation baseline length. Large homogeneous liquid scintillator detectors,
while offering excellent energy resolution, are traditionally very limited in
their capabilities of measuring event directionality. In this paper, we present
a novel directionality reconstruction method for atmospheric neutrino events in
large homogeneous liquid scintillator detectors based on waveform analysis and
machine learning techniques. We demonstrate for the first time that such
detectors can achieve good direction resolution and potentially play an
important role in future atmospheric neutrino oscillation measurements.Comment: Prepared for submission to PR
SUMOylation Represses Nanog Expression via Modulating Transcription Factors Oct4 and Sox2
Nanog is a pivotal transcription factor in embryonic stem (ES) cells and is essential for maintaining the pluripotency and self-renewal of ES cells. SUMOylation has been proved to regulate several stem cell markers' function, such as Oct4 and Sox2. Nanog is strictly regulated by Oct4/Sox2 heterodimer. However, the direct effects of SUMOylation on Nanog expression remain unclear. In this study, we reported that SUMOylation repressed Nanog expression. Depletion of Sumo1 or its conjugating enzyme Ubc9 increased the expression of Nanog, while high SUMOylation reduced its expression. Interestingly, we found that SUMOylation of Oct4 and Sox2 regulated Nanog in an opposing manner. SUMOylation of Oct4 enhanced Nanog expression, while SUMOylated Sox2 inhibited its expression. Moreover, SUMOylation of Oct4 by Pias2 or Sox2 by Pias3 impaired the interaction between Oct4 and Sox2. Taken together, these results indicate that SUMOylation has a negative effect on Nanog expression and provides new insights into the mechanism of SUMO modification involved in ES cells regulation
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