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Intelligent 5G-aided UAV positioning in high-density environments using neural networks for NLOS mitigation
Get PDFThe accurate and reliable positioning of unmanned aerial vehicles (UAVs) in urban environments is crucial for urban air mobility (UAM) application, such as logistics, surveillance, and disaster management. However, global navigation satellite systems (GNSSs) often fail in densely populated areas due to signal reflections (multipath propagation) and obstructions non-line-of-sight (NLOS), causing significant positioning errors. To address this, we propose a machine learning (ML) framework that integrates 5G position reference signals (PRSs) to correct UAV position estimates. A dataset was generated using MATLAB’s UAV simulation environment, including estimated coordinates derived from 5G time of arrival (TOA) measurements and corresponding actual positions (ground truth). This dataset was used to train a fully connected feedforward neural network (FNN), which improves the positioning accuracy by learning patterns between predicted and actual coordinates. The model achieved significant accuracy improvements, with a mean absolute error (MAE) of 1.3 m in line-of-sight (LOS) conditions and 1.7 m in NLOS conditions, and a root mean squared error (RMSE) of approximately 2.3 m. The proposed framework enables real-time correction capabilities for dynamic UAV tracking systems, highlighting the potential of combining 5G positioning data with deep learning to enhance UAV navigation in urban settings. This study addresses the limitations of traditional GNSS-based methods in dense urban environments and offers a robust solution for future UAV advancements.The first author acknowledges the Ministry of Higher Education and Scientific Research of Libya for supporting his PhD studies.Aerospac
A behaviourally informed heuristics-framework for net zero transformation in manufacturing
Get PDFTransitioning to net zero emissions in manufacturing is fraught with challenges, from navigating uncertainties and making critical trade-offs, to overcoming biases and information asymmetry. Such behavioural challenges could potentially result in bounded rationality, where decision-makers operate under limited information and cognitive constraints. This paper introduces a framework that employs behaviourally informed heuristics to simplify the complexity of net-zero transformation. By incorporating behavioural model of rational choice and decision-making rules, the framework could help manufacturing decision-makers to manage uncertainties and cognitive limitations, thus broadening the toolkit for navigating the reduction of carbon emissions.20th Global Conference on Sustainable Manufacturing (GCSM 2024).Lecture Notes in Mechanical Engineerin
Enhancing methane production by adding Fe3+ in mesophilic anaerobic digestion of cheese waste
Get PDFThe advancements in cheese production technology have resulted in increased waste generation, especially in the form of liquid byproducts left over after the milk clotting process. This research examines the possibility of using cheese waste to produce methane (CH4) through mesophilic anaerobic digestion and investigates how adding iron (Fe) can improve CH4. Field experiments were conducted to evaluate the effects of varying concentrations of cheese waste (0–33.33 g/L) and FeCl3 (0–3.0 g/L) on CH4 yield. Results revealed that the addition of 2 g/L FeCl3 achieved the highest cumulative CH4 yield and production rate, with increases of 68% and 65% over the control, respectively. The study also monitored pH levels and found that the best treatment maintained a near-neutral pH of 6.79 by day 50, which is important for sustaining effective microbial activity. This study highlights the potential of incorporating Fe supplementation to optimize CH4 yields from cheese waste and other organic substrates, contributing to more sustainable and efficient renewable energy production.Partial financial support for this research was received from the Directorate of Research and Community Services Universitas Brawijaya (DRPM UB) and the Faculty of Agricultural Technology, Universitas Brawijaya.8th International Conference on Green Agro-Industry and Bioeconomy (ICGAB 2024)BIO Web of Conference
Coriolis massflow measurement errors due to inhomogeneous entrained particles: an analytical model
Get PDFThe Coriolis mass flow meter is a critical instrument used in various industries for the precise measurement of mass flow rate and density of a fluid. Despite its widespread use, the impact of entrained particles within the fluid can significantly affect the accuracy of the meter, leading to potential errors and inefficiencies. Previous calculations of the mass flow errors assumed that the entrained particles are uniformly distributed along the axis of the measurement tube. In this paper we extend the analytical investigation of the measurement errors beyond the previous work to the regime of non-uniform density distribution of the entrained particles. We provide a clear analysis of the contributions of various physical effects in this regime to the mass-flow measurement error.The authors would like to express their gratitude to Endress + Hauser Flow for supporting the study.Flow Measurement and Instrumentatio
Variable rate application of plant protection products (fungicides on winter wheat)
Get PDFCorstanje, Ronald - Associate SupervisorVariable rate application (VRA) has the potential to allow farmers to use the most
suitable dose rate of fungicides required for their winter wheat fields. Currently,
the dominant practice is to apply fungicides at a uniform dose rate irrespective of
in field variability. VRA could reduce fungicide costs, prevent chemical resistance,
and reduce environmental damage. Whilst VRA is more commonplace in
Nitrogen applications and more recently plant growth regulator (PGR)
applications, there is still a hesitancy to use VRA for fungicide applications. With
the removal of fungicide active ingredients and resistance to actives, the future
of fungicide application is to determine the most appropriate dose and reducing
over-spraying where possible. The primary aim of this thesis was to understand
how to achieve VRA of fungicides on winter wheat, most effectively and efficiently
in the future. To achieve this, several research gaps were investigated. Research
was conducted into the ‘state of the art’ VRA technology finding that the main
barriers are cost and perceived risk of inconsistency of effect. A laboratory trial
was conducted in 2018 to study the deposition of a dye representative of
fungicide through the winter wheat growing season. Destructive sampling was
conducted to determine the variation in quantity of dose rate per gram of biomass
for each fungicide application timing, finding the later growth stages received the
greatest dose but the dose relative to the biomass was lower than earlier growth
stages. In 2019, March – June, a field study was conducted over two farms to
measure the spatial and temporal variation in volumetric biomass and determine
if NDVI is a suitable basis for application decisions, finding that monitoring at T0
and T1 growth stages was best for reflecting canopy variability. From this, a new
method was piloted to extract NDVI min and max values from 43,000 winter
wheat fields in 2018. This was to understand the range of variation, in NDVI
values at T1, in winter wheat fields is enough to continue investing in VRA.
Finally, a cost benefit analysis was performed comparing a standard uniform dose
and a VRA system, finding a saving of £13.82/ha on one farm from one VRA
spray (T1). If a similar saving was made at T0, T2, and T3 an overall saving would
be made of £55.28/ha. This study provides methodology for conducting VRA and
a foundation for future VRA investigations.PhD in Environment and Agrifoo
Field experiment in Ugandan cassava stores reveals that slow release SO2 sheets suppress aflatoxigenic fungi, resulting in undetectable aflatoxin B1 levels
No full textAflatoxin contamination in stored crops poses a serious threat to public health and food safety, particularly in tropical regions where warm, humid conditions favour fungal growth. Cassava, a staple in many developing countries, is vulnerable to aflatoxin B1 (AFB1) contamination during storage, necessitating effective mitigation strategies. This study evaluated the efficacy of sodium metabisulphite (NaMBS) sheets, which slowly release sulphurdioxide (SO2), in reducing aflatoxigenic fungal load and aflatoxin B1 (AFB1) concentrations in cassava chips (sliced pieces of cassava root used for cassava flour production). Storage trials were conducted in three Ugandan districts with contrasting climates, using two bag types: traditional polypropylene and hermetic Purdue Improved Crop Storage (PICS) bags-with and without NaMBS. The study employed a three-way factorial randomized complete block design (bag type, NaMBS treatment, and district). Fungal load and AFB1 were monitored for 30 days using DG-18 media and LC-MS/MS, respectively. Aspergillus section Flavi showed the highest initial fungal load (3.57 × 106 cfu/g), which significantly (P < 0.01) decreased after NaMBS treatment. A significant bag × NaMBS interaction (P < 0.001) was observed, with PICS bags consistently outperforming traditional bags. District climate did not significantly affect fungal counts (P = 0.06) but strongly influenced AFB1 levels (P < 0.01). Untreated traditional bags showed the highest AFB1 (146.6 μg/kg), while NaMBS-treated PICS bags reduced AFB1 to 0.23 μg/kg, representing up to 99.9% reduction. These findings provide foundational evidence that NaMBS sheets can effectively suppress aflatoxigenic fungi and reduce AFB1 contamination in cassava stores. Further work should assess residual NaMBS safety and consumer acceptability.Commonwealth Scholarship Commission, National Agricultural Research OrganisationThis research was initially supported by the Government of Uganda through the Directorate of Research and Graduate Research Training at Mbarara University of Science and Technology, and was subsequently funded by the Commonwealth Scholarship Commission, United Kingdom.Food Contro
Variable geometry exhaust system for low specific thrust turbofans
No full textThis research was undertaken within the context of the Rolls-Royce University
Technology Centre (UTC) in Aero System Design, Integration & Performance at
Cranfield University, hosted by the Centre for Propulsion Engineering.
Aero-engine designers are moving towards lower specific thrust and higher
bypass ratio engines in an attempt to improve mission fuel burn. When going to
Ultra-High bypass ratio and very low specific thrust engines there may be a
possibility for further mission fuel burn improvement equipping such engines with
a ‘Variable Geometry Exhaust System’ (VGES). This system might also be
required when looking at the possibility of surge of the compressor components
in very low specific thrust engines. The performance improvement of the VGES
could arise from the aspect that this system includes a mini-mixer, where part of
the bypass flow is mixed with the core flow. The idea behind the mini-mixer is the
possibility to gain the benefits of a mixed exhaust turbofan while reducing the
losses these systems introduce. This is because the mini-mixer will not mix the
complete exhaust flows. Therefore, the mixing chamber will not require the same
length as a regular mixed exhaust system. Next to the mini-mixer the VGES
presents the possibility to vary four flow areas within the engine’s exhaust system,
hence potentially increasing the available ‘handles’ for optimum performance and
preventing surge of the compressors. Two of these variable areas are exhaust
nozzles and the other two are the inlets to the mixer. The main focus of this PhD
programme was the representative simulation of the VGES with a mini-mixer,
taking all important pressure losses, as well as mixing efficiency into account.
The work reported herein discusses the engine cycle optimisation, weight and
mission fuel burn studies undertaken.
For this research two different turbofan engine architectures are examined, the
‘direct-drive’ and the ‘geared’ configuration, where the fan is coupled to the Low
Pressure Turbine (LPT) via a reduction gearbox. The mission profile investigated
is for an A330-size aircraft with a range of 3000 nm. Technology limitations are
set for a potential entry into service in 2025-2030. The results of this study
showed that regardless of how many areas were allowed to vary of the four
variable areas, no significant performance benefit was present. In regards to
surge possibility with the current assumption for the very low specific thrust
engine configurations there was no need for the variable areas. The results of the
study also demonstrate that the mini-mixer itself can improve engine performance
and mission fuel burn. With the current assumptions the maximum reduction in
mission fuel burn observed is 0.5% at the lower fan diameter range investigated
for the geared configuration. For the direct drive the maximum reduction found
was 0.1% The reason for the direct-drive configuration having less improvement
is due to the limit the LPT lets the fan FPR be reduced, which influenced the
thrust gain from the mini-mixer, compared to the geared configuration.
Furthermore, for both architectures going to higher fan diameters, there is no
benefit anymore present by using the mini-mixer. The reason for this is that the
thrust gain is numerically associated with the reduction in FPR and LPT pressure
ratios when comparing to an unmixed engine with the same Specific Thrust.
When the FPR of an unmixed is already very small the amount of thrust gain
when using a mixed exhaust system can achieve is very small at this point the
losses start outweighing the benefits.
This research programme has made a useful contribution to knowledge in various
areas of engineering and scientific relevance. First of all the viability of a novel
piece of technology was investigated, with potential benefits as well as practical
limitations identified. The influence of mixing efficiency and pressure loss in a
complex, mini-mixer arrangement were studied and a useful methodology was
established to identify performance trade-offs. Also, the study looked into the
effect on high-bypass ratio turbofan engine performance of using multiple
variable nozzle areas simultaneously. The results are reported herein for the very
first time.PhD in Aerospac
Can large language models mimic airline passenger preferences?
No full textLarge Language Models (LLMs) are being used in the air travel sector to simulate passenger behaviour. While commercial LLMs provide ready-made solutions, concerns over reliability limit widespread use. This paper leverages decades of discrete-choice research to audit 23 LLMs’ responses to a flight-ticket choice experiment with zero-shot prompting. The results of our logit regressions indicate that LLMs can simulate highly rational preferences, correctly sign ticket attributes, differentiate between relevant and irrelevant factors, and deliver plausible willingness-to-pay estimates. However, LLMs might fall short in replicating nuanced demographic segmentation and show sensitivity to cultural bias in their training data. Their outputs are best used to inform early-stage modelling, with traditional market research remaining essential for validation.Artificial Intelligence for Transportatio
Sinking into the unthinkable: using extreme fiction to study future crises
No full textPurpose:
We aim to show how extreme fiction can be used to study possible future extreme events, allowing researchers to get “up close” to potentially dangerous settings.
Design/methodology/approach:
How can research help to understand a world that has become more unpredictable and dangerous? We assess the use of fiction as research material and explore dramatized movie accounts of possible future accidents, crises and disasters through “extreme fiction” – a genre which has been underutilized. We assess the benefits and limitations of using extreme fiction as a research resource. An example of how extreme fiction can challenge assumptions and generate novel theoretical insights is presented.
Findings:
Extreme fiction can help us to anticipate, understand and prepare for possible future crises. This medium can also prompt challenges to taken-for-granted assumptions and trigger fresh theoretical insights.
Research limitations/implications:
The use of extreme fiction as research material is limited by concerns of credibility, evidential boundaries and selectivity. We suggest ways of responding to these challenges.
Practical implications:
This approach gives researchers an additional lens through which to explore future accidents, crises and disasters. Improved understanding improves our ability to anticipate, plan and respond more effectively to such events.
Social implications:
Exposure to fictional crises in movies and other media can increase resilience to actual events. Disaster movies can be seen as educational as well as entertaining.
Originality/value:
Implausible, unrealistic, exaggerated and sensationalized, fictional accounts of extreme events have been overlooked by research. But to develop understanding of future possibilities and prompt fresh thinking, implausibility is a useful property of these accounts.Qualitative Research in Organizations and Management: An International Journa
Comprehensive comparison of correction techniques for low-cost air quality sensors: the impact of device type and deployment environment
No full textLow-cost air quality sensors have shown great promise as a complement to high-cost reference and equivalent methods. Though not currently as accurate, their low barrier of entry and smaller form factor allow them to be deployed in greater numbers, thus enabling air quality measurements to be made at a far higher spatial and temporal resolution than previously possible. However, their measurements require corrections as they suffer from both short-term biases (e.g., changes in environmental conditions such as temperature and humidity), and long-term measurement drift due to degradation. Many studies have focused on calibration and re-calibration of sensors, but fewer focus on correcting pre-calibrated sensor measurements. Correcting measurements is a likely scenario for people buying off-the-shelf devices, as they will not have access to the raw data that underpins the measurements, such as sensor voltages. Previous studies focused on a small range of correction techniques, without accounting for the variances that can occur between devices or locations. This work aimed to perform a comprehensive assessment of different correction techniques applied to air quality sensor systems. More than 470,000 unique measurement corrections were tested across two sites to determine best practices for correction campaigns going forward, resulting in a far more robust study than previous works. It highlights the large variances in results that occurred between sites, particularly for NO2, with results often more impacted by device type and location than the regression technique used. Simpler linear models were also found to perform just as well as, and sometimes better than, more complex non-parametric techniques. This study highlights that, though a strong focus is often put on comparing different regression methods, the choice of technique has less impact than the configuration of the device or the conditions of the co-location site. Therefore, future studies should focus less on small-scale comparisons of regression techniques and more on how to improve the transferability and applicability of results from a co-location campaign to another.The Cranfield University Urban Observatory is funded by the UKCRIC: Urban Observatories (Strand B)—(EPSRC EP/P016782/1) and the UKCRIC—CORONA: City Observatory Research platfOrm for iNnova-tion and Analytics projects (EPSRC EP/R013411/1). These are supported by the UKCRIC Coordination Node (EPSRC EP/R017727/1), which funds UKCRIC’s ongoing coordination. It is also supported by the Cranfield University Net Zero Research Airport project, funded by Research England’s UK Research Partnership Investment Fund (UKRPIF) Net Zero Funding Scheme.npj Climate and Atmospheric Scienc