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Gimbal control of an airborne Pan-Tilt-Zoom camera for visual search
Get PDFThis paper presents the development of an optimized visual search algorithm for unmanned aerial vehicle (UAV) equipped with Pan-Tilt-Zoom cameras, designed to account for platform dynamics and disturbances. The study involves the design and evaluation of various gimbal control strategies to stabilize the camera’s orientation, ensuring effective area coverage despite UAV attitude changes. A comparative analysis of control methods, including Proportional–integral–derivative (PID), Disturbance Observer (DOB), Iterative Learning Control, Internal Model Control, Active Disturbance Rejection Control, and their combinations, highlights the importance of advanced controllers in maintaining camera stability under complex conditions such as coriolis, centripetal, and gyroscopic disturbances. The combination of PID and DOB provided superior disturbance rejection, making it a suitable choice for challenging flight scenarios. Additionally, an optimized coverage path planning algorithm was developed to maximize image coverage while minimizing flight time, turns, and overlap, taking into account field of view, resolution, and terrain constraints. Simulation results demonstrate the effectiveness of this approach, achieving full area coverage with enhanced efficiency. The framework developed in this study provides a solid foundation for reliable and precise UAV-based search operations, particularly in dynamic and complex environments.AIAA SCITECH 2025 Foru
Evaluating mobile-based data collection for crowdsourcing behavioral research
Get PDFOnline crowdsourcing platforms such as MTurk and Prolific have revolutionized how researchers recruit human participants. However, since these platforms primarily recruit computer-based respondents, they risk not reaching respondents who may have exclusive access or spend more time on mobile devices that are more widely available. Additionally, there have been concerns that respondents who heavily utilize such platforms with the incentive to earn an income provide lower-quality responses. Therefore, we conducted two studies by collecting data from the popular MTurk and Prolific platforms, Pollfish, a self-proclaimed mobile-first crowdsourcing platform, and the Qualtrics audience panel. By distributing the same study across these platforms, we examine data quality and factors that may affect it. In contrast to MTurk and Prolific, most Pollfish and Qualtrics respondents were mobile-based. Using an attentiveness composite score we constructed, we find mobile-based responses comparable with computer-based responses, demonstrating that mobile devices are suitable for crowdsourcing behavioral research. However, platforms differ significantly in attentiveness, which is also affected by factors such as the respondents’ incentive for completing the survey, their activity before engaging, environmental distractions, and having recently completed a similar study. Further, we find that a stronger system 1 thinking is associated with lower levels of attentiveness and acts as a mediator between some of the factors explored, including the device used and attentiveness. In addition, we raise a concern that most MTurk users can pass frequently used attention checks but fail less utilized measures, such as the infrequency scale.Behavior Research Method
Current status of forensic anthropology in the Middle East and North Africa (MENA) region
Get PDFBackground
Forensic anthropology has evolved significantly, from its foundations in the nineteenth century to its formal establishment in the twentieth century and in particular with modern advancements from the 1970s onward. Its role in human rights investigations during the 1980s in Latin America and the 1990s in the Balkans, exemplifies its global impact. However, the practice and application of forensic anthropology in the Middle East and North Africa (MENA) region remain underexplored. This study assesses the current status of forensic anthropology in this region through a brief literature review and online interviews with academics and practitioners in forensic anthropology or closely related disciplines. The interviews addressed the medico-legal system structure, forensic science capabilities, training efforts, practitioner availability, case types (medico-legal and humanitarian), and resources like radiological imaging.
Results
The study revealed that forensic anthropology is largely underutilized in the MENA region’s medico-legal death investigation systems. Factors such as limited human capital, lack of discipline awareness, varying legal and procedural systems, and insufficient academic infrastructure hinder its integration. Challenges include political instability, safety concerns for practitioners, and inadequate resources. The study highlights ongoing efforts by practitioners to improve the field through theoretical and practical training, capacity building, and resource development.
Conclusion
The findings underscore the need for strategic investments to strengthen forensic anthropology in the MENA region. Recommendations include enhancing education and training, fostering interdisciplinary collaboration, disseminating scientific knowledge, increasing access to resources, and revising medico-legal frameworks. These measures can bridge existing gaps and advance forensic anthropology’s role in medico-legal and humanitarian contexts.The study presented was supported by the Wenner-Gren Foundation under the Wadsworth International Fellowship, Gr. WIF-286.Egyptian Journal of Forensic Science
A passivity-based method for accelerated convex optimisation
Get PDFThis study presents a constructive methodology for designing accelerated convex optimisation algorithms in continuous-time domain. The two key enablers are the classical concept of passivity in control theory and the time-dependent change of variables that maps the output of the internal dynamic system to the optimisation variables. The Lyapunov function associated with the optimisation dynamics is obtained as a natural consequence of specifying the internal dynamics that drives the state evolution as a passive linear time-invariant system. The passivity-based methodology provides a general framework that has the flexibility to generate convex optimisation algorithms with the guarantee of different convergence rate bounds on the objective function value. The same principle applies to the design of online parameter update algorithms for adaptive control by re-defining the output of internal dynamics to allow for the feedback interconnection with tracking error dynamics.2024 IEEE 63rd Conference on Decision and Control (CDC
Tactical planning interception enhancement using expert learning - twin delayed deep deterministic policy gradient
No full textThe accurate interception of adversarial unmanned aerial vehicles (UAVs) is paramount for the protection of people and national facilities. Urban cities pose several challenges for target interception algorithms due to the presence of buildings and flying constraints that limit the manoeuvrability of UAVs for target interception. Deep Reinforcement Learning (DRL) algorithms have been deployed to solve the task effectively. However, the design of its inner elements such as the reward function and action distribution limits its generalisation to different environments. To solve this issue, this paper proposes a novel twin-delayed deep deterministic policy gradient (TD3) based expert learning algorithm that combines previous expert experiences with on-line learning to regularise and improve the policy learning effectively. This is done by following an action distribution algorithm that allows a learner agent to mix its own actions with expert ones for learning improvement and fast convergence. Extensive simulation studies are carried out under diverse urban cities configurations to show the robustness and high-accuracy of the proposed approach compared with traditional DRL baseline algorithms.IEEE Transactions on Intelligent Vehicle
Methods for separating close natural frequencies
No full textWhen close natural frequencies occur, they may cause complications when performing experiments and require special attention and treatment in modelling. It is shown that close and even identical natural frequencies can occur in linear structures. However, these are unlikely to occur if one parameter in the system is varied in an attempt to tune a system. Adding damping to a system with close natural frequencies may result in an adverse result where one mode has reduced damping and another increased damping. A method based on narrow band filtering is presented which enables close modes to be separated so that the natural frequency and damping of each mode can be identified. This method involves reversing the time history of vibration decay prior to filtering. Finally, the effect of nonlinearities is examined. A new algorithm based on barycentric interpolation is demonstrated. This algorithm can be used for model fitting linear or nonlinear systems and is shown to be near perfect. A case is demonstrated that uses the nonlinear model to separate close modes. However, a counter example shows that this may not be generalised.ASME 2025 Pressure Vessels & Piping Conferenc
Mechatronics numerical modelling for integrated turbo-electric techno-economic environmental risk assessment
No full textPilidis, Pericles - Associate SupervisorLong-term targets from the aerospace administration are to have cleaner, cost-efficient, and more performance-efficient transportation. The National Aeronautics and Space Administration (NASA) has proposed several solutions to hybrid technology, of which the turbo-electric distributed propulsion (TeDP) model is one of the latest promising models. This research project presents numerical modelling of the integrated TeDP model through the method of assisting technical performance, considering the economic and environmental risks. The contribution to numerical modelling is an integrated electrical module on the academic multidisciplinary Cranfield University gas-turbine TurboMatch® simulation tool with the projected method. In piloting this project, the outcome of this work advances the knowledge of TeDP and the future technology of aviation-distributed propulsion.
Moreover, a proper simulation tool to assist TeDP and ‘more electric aviation’ has been upgraded in TurboMatch. In addition, an integrated development environment (IDE) extension for TurboMatch was developed to investigate the electrical grid in TeDP. This work presents a toolkit for assessing the power and efficiency profiles of the electrical network specified for TeDP. From the given level of thrust, the methodology was used to evaluate and optimise the electrical network. A number of integration electric propulsion models were developed to demonstrate the assisting method for redundancy and reliability improvement. The total goal was to initialise the features of the TeDP mechatronics and electrical grid with the best technical, economic, and environmental solutions for the greatest efficiency.
The implication of this research is to understand the concept of TeDP using the use-case study of NASA’s N3-X conceptual proposal for project progress validation. The contribution knowledge lies in the area of the numeric model and the method to assist TeDP using the devised techno-economic environmental risk assessment (TERA) concept. The project inputs focus on future long-term goals for intelligent TeDP.PhD in Aerospac
Techno-economic, environmental and risk analysis of a hydrogen airliner family market entry
Get PDFCivil aviation is in a profound transition motivated by the need to reduce its
environmental impact. Most civil aviation institutions and stakeholders are now
committed to reach net zero by 2050, though there is no feasible path drafted to
achieve this goal. Projected energy efficiency improvements, and the use of
sustainable aviation fuels could provide a significant reduction in CO₂ emissions,
but to reach net zero all emissions should be eliminated or compensated, and
none of these solutions achieve the target.
Hydrogen as fuel has zero emissions of CO₂ and can address aviation non-CO₂
emissions in an effective manner, to become a true zero emission alternative.
Optimising a hydrogen aircraft to match the capabilities and flexibility of the
existing narrowbody or the widebody point to point ultra-long-range capacity will
take decades. An speculative alternative to expedite the introduction of hydrogen
aircraft using existing technology is the focus of this research. A second and third
generation of hydrogen aircraft could bring additional benefits in terms of
capability and fuel consumption. But the first generation is focused on a swift
change. An evaluation of the capabilities achievable with today’s technology and
tube and wing configuration is performed.
A redesigned double deck aircraft using the A380 as a baseline, with modified
wings and engines, and with a variety of tank configurations is investigated as an
initial airliner family. It can provide passenger capacities of 388 to 232 with a
range of 3,300 nm to 5,600 nm, respectively. Such airliner family could start
decarbonising the long-range sector in 15 years. It offers potential to go one-stop
to anywhere in the world. A high-capacity version can travel 1,800 nm with 720
passenger is also studied as a solution for high demand city pair traffic. These
findings were presented in ISABE 2022 and ICAS 2022 and published in the
ISABE special issue of the Aeronautical Journal. The paper ‘Propulsion System
Integration for a First-Generation Hydrogen Airliner’ was awarded a Bronze Prize
by the RAeS in 2022 and was the 5th most downloaded paper in 2022 in the
Aeronautical Journal with 1599 downloads.ii
Cryogenic storage is one of the most critical technologies to be addressed. Lightly
insulated tanks can extend the range of the aircraft for a given tank volume, but
they are unlikely to be used in a first generation due to the need to manage the
vented vapour at the airport. Tank architecture and configurations are explored
to understand the current and future implications, finding that diameter and
dormancy time requirements are the key design parameters that drive the weight
of the tank. This work significantly contributed to win three work packages for ATI
managed FlyZero project – Tank Design, Fuel System and Combustion
consultancy and Advanced Propulsion – where the methods developed in the
thesis were adopted. Particularly relevant was the tank weight finally assumed by
FlyZero due to the outcomes of this work, which was half the value assumed in
most recent studies.
A final exploration looks at the emissions that this swift change route could lead
to. Complete decarbonization is not achieved until 2080, despite the early
introduction in 2035 of the hydrogen airliners. Nevertheless, it provides a
decarbonizing solution superior in the long term to other the solutions being
explored based on biofuels.PhD in Aerospac
A biocubesat compatible payload for future space systems: development of a second generation bammsat payload for stratospheric balloon flight
Get PDFHobbs, Stephen E. - Associate SupervisorNational space agencies have announced planned long-duration crewed
missions beyond Low Earth Orbit. It is critical to understand the impact of long-
duration microgravity and especially deep-space radiation exposure on humans.
There is a knowledge gap concerning the effects of the space environment on
humans, our human microbiome and associated Earth biology needed to support
human activities in space.
There is also a renaissance in the space industry, as seen in increased space
activities and commercialisation. This is driven by the growing international
activities, shifting funding landscape, and change in commercialisation activities.
It is thought that the space industry is at an inflexion point for a full-scale
microgravity research programme (DiFrancesco & Olson, 2015). With a
newfound interest in life science and microgravity, there is a need for validating
data on space-based biological models for terrestrial and space applications.
These biological studies require frequent access and many discrete samples
before they can be understood and accepted by the scientific community.
CubeSats offer opportunities to improve spaceflight access with reduced
development time using standardised components, more frequent flight
opportunities, and reduced mission costs. Over the last decade, a series of seven
bioCubeSats have been launched into orbit by NASA and SpacePharma:
GeneSat, PharmaSat, O/OREOS, SporeSat, Dido-2, EcAMSat and Dido-3. The
term bioCubeSat refers to a CubeSat with a biological payload onboard. These
bioCubeSats proved the feasibility and de-risk the concept of performing a
biological experiment on CubeSat. However, these bioCubeSats have design
limitation that inhibits the types of organisms and experiments that could be
performed onboard. The design limitation affects the number of independent
discrete samples, pre-flight handling capability, and sensor types within its
system.
Cranfield University has been developing an alternative bioCubeSat concept
named BAMMsat, for application in LEO and beyond LEO. BAMMsat stands for
Bioscience, Astrobiology, Medical, and Material science on CubeSats. The
versatile platform builds upon the typical experiment need of these scientific
fields, such as i) the need to house multiple samples, ii) the need to maintain
viable samples in an appropriate space environment, iii) the need to artificially
perturb the samples and (iv) the need to monitor the samples. BAMMsat was
developed to address the knowledge gap to fly a broader range of organisms and
experiments enabled by its Rotary Valve, Multi-Chamber Sample Disc, and richer
sensor offering.
BAMMsat could be an asset to provide autonomous and high-throughput
experiments as an R&D instrument for space bioscience and biotechnology. At a
lower entry cost combined with the capability to perform an autonomous in-situ
data measurement, BAMMsat could increase life science in microgravity either
for using space for a terrestrial application and supporting future human
exploration of the Moon and Mars.
The PhD thesis reports on PhD research performed to advance the BAMMsat
concept developing the 1st gen. laboratory breadboard (TRL 4) into a 2nd gen.
technology demonstration hardware (TRL 5/6) and bridging the gap towards a 3rd
gen. spaceflight mission, currently planned to be on-board the ISS. During the
PhD, five different subsystems were developed: the multi-chamber sample disc,
rotary valve, compact brightfield microscope, fluidic subsystem, Geneva gear
mechanism, and mechanical housing. These subsystems were packaged into a
2U CubeSat payload version of BAMMsat. The 2U CubeSat payload was flown
under the BAMMsat-on-BEXUS (BoB) mission. BoB mission was an experiment
using live C. elegans from Cranfield University and the University of Exeter,
performing a technology and operation demonstration of a 2nd gen. design of
BAMMsat hosted on a stratospheric balloon at an altitude of ~28 km above the
ground under the BEXUS programme.PhD in Aerospac
Revealing prostate calcification heterogeneity through their elemental distribution
Get PDFThe Supporting Information is available free of charge at: https://pubs.acs.org/doi/10.1021/cbmi.5c00050.
Details about elemental fitting, statistical and p values for Kendall’s tau and Kruskal−Wallis, elemental ratios for clusters, and example CT images.Calcifications across the body offer snapshots of the surrounding ionic environment at the time of their formation. Links between prostate calcification chemistry and cancer are becoming of increasing interest, particularly in identifying biomarkers for disease. This study utilizes X-ray fluorescence mapping of 72 human prostate calcifications, measured at the I18 beamline at the Diamond Light Source, to determine the links between calcifications and their environment. This paper offers the first investigation of the elemental heterogeneity of prostate calcifications, demonstrating lower relative levels of minor elements at the calcification center compared to the edge but higher levels of zinc. Importantly, this study uniquely presents links between average Fe, Cr, Mn, Cu, and Ni ratios and grade Group (a classification system for urological tumors, specifically for prostate cancer), highlighting a potential avenue of exploration for biomarkers in prostate calcifications.This work was supported by Cancer Research UK [EDDPMAMay21\100010].Chemical & Biomedical Imagin