Cranfield Defence and Security

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Open Access
2016 British Crystallographic Association (BCA) Spring Meeting, April 4–7, 2016
(Cambridge University Press, 2016-12) Rendle, D
Review of the 2016 British Crystallographic Association (BCA) Spring Meeting, April 4–7, 2016
Open Access
3D automatic target recognition for future LIDAR missiles
(IEEE, 2017-01-10) Kechagias-Stamatis, Odysseas; Aouf, Nabil; Richardson, Mark A.
We present a real-time three-dimensional automatic target recognition approach appropriate for future light detection and ranging-based missiles. Our technique extends the speeded-up robust features method into the third dimension by solving multiple two-dimensional problems and performs template matching based on the extreme case of a single pose per target. Evaluation on military targets shows higher recognition rates under various transformations and perturbations at lower processing time compared to state-of-the-art approaches.
Open Access
3D automatic target recognition for missile platforms
(2017-05) Kechagias Stamatis, Odysseas; Aouf, Nabil
The quest for military Automatic Target Recognition (ATR) procedures arises from the demand to reduce collateral damage and fratricide. Although missiles with two-dimensional ATR capabilities do exist, the potential of future Light Detection and Ranging (LIDAR) missiles with three-dimensional (3D) ATR abilities shall significantly improve the missile’s effectiveness in complex battlefields. This is because 3D ATR can encode the target’s underlying structure and thus reinforce target recognition. However, the current military grade 3D ATR or military applied computer vision algorithms used for object recognition do not pose optimum solutions in the context of an ATR capable LIDAR based missile, primarily due to the computational and memory (in terms of storage) constraints that missiles impose. Therefore, this research initially introduces a 3D descriptor taxonomy for the Local and the Global descriptor domain, capable of realising the processing cost of each potential option. Through these taxonomies, the optimum missile oriented descriptor per domain is identified that will further pinpoint the research route for this thesis. In terms of 3D descriptors that are suitable for missiles, the contribution of this thesis is a 3D Global based descriptor and four 3D Local based descriptors namely the SURF Projection recognition (SPR), the Histogram of Distances (HoD), the processing efficient variant (HoD-S) and the binary variant B-HoD. These are challenged against current state-of-the-art 3D descriptors on standard commercial datasets, as well as on highly credible simulated air-to-ground missile engagement scenarios that consider various platform parameters and nuisances including simulated scale change and atmospheric disturbances. The results obtained over the different datasets showed an outstanding computational improvement, on average x19 times faster than state-of-the-art techniques in the literature, while maintaining or even improving on some occasions the detection rate to a minimum of 90% and over of correct classified targets.
Open Access
3D conformal antennas for radar applications
(2018) Fourtinon, L; Balleri, Alessio
Embedded below the radome of a missile, existing RF-seekers use a mechanical rotating antenna to steer the radiating beam in the direction of a target. Latest research is looking at replacing the mechanical antenna components of the RF seeker with a novel 3D conformal antenna array that can steer the beam electronically. 3D antennas may oer signicant advantages, such as faster beamsteering and better coverage but, at the same time, introduce new challenges resulting from a much more complex radiation pattern than that of 2D antennas. Thanks to the mechanical system removal, the new RF-seeker has a wider available space for the design of a new 3D conformal antenna. To take best benets of this space, dierent array shapes are studied, hence the impact of the position, orientation and conformation of the elements is assessed on the antenna performance in terms of directivity, ellipticity and polarisation. To facilitate this study of 3D conformal arrays, a Matlab program has been developed to compute the polarisation pattern of a given array in all directions. One of the task of the RF-seeker consists in estimating the position of a given target to correct the missile trajectory accordingly. Thus, the impact of the array shape on the error between the measured direction of arrival of the target echo and its true value is addressed. The Cramer-Rao lower bound is used to evaluate the theoretical minimum error. The model assumes that each element receives independently and allows therefore to analyse the potential of active 3D conformal arrays. Finally, the phase monopulse estimator is studied for 3D conformal arrays whose quadrants do not have the same characteristics. A new estimator more adapted to non-identical quadrants is also proposed.
Open Access
3D Lagrangian particle tracking of a subsonic jet using multi-pulse Shake-The-Box
(Elsevier, 2021-01-19) Manovski, Peter; Novara, Matteo; Karthik, Nagendra; Mohan, Depuru; Geisler, Reinhard; Schanz, Daniel; Agocs, Janos; Godbersen, Philipp; Schröder, Andreas
Three-dimensional (3D) Lagrangian Particle Tracking (LPT) was performed on a subsonic jet flow at Mach 0.506 and 0.845 generated by a round nozzle with diameter-based Reynolds numbers of 1.7×105 and 3.1×105, respectively. The Multi-Pulse Shake-The-Box (MP-STB) technique was employed to reconstruct particle tracks along the four-pulse sequences, which were obtained by using orthogonally polarised light to separate the pulses on camera images. The MP-STB method applied here has a number of differences compared to previous publications, in particular, a new adaptive search radii approach and an iterative strategy and particle track validation criteria that have been customised for high subsonic/transonic flows. A description of this methodology is given followed by presentation of the instantaneous 3D flow velocity and material acceleration particle tracks. By ensemble-averaging the scattered instantaneous measurements extracted from individual particle tracks into small volumetric bins, highly resolved statistical quantities were obtained. The performance of MP-STB was assessed by comparing velocity profiles with published particle image velocimetry (PIV) data-sets. MP-STB was better able to resolve the steep velocity gradients, in particular the thin jet shear layer near the nozzle exit. At this location the MP-STB results also yielded higher turbulence intensities compared with the reported studies for similar flow conditions. The MP-STB acceleration flow statistics were compared for the two Mach numbers, and for the Mach 0.506 case, higher levels of normalised acceleration and fluctuations were found. The position accuracy of the 3D imaging system was quantified and it was found that the use of two different states of polarisation had a direct impact on the accuracy and the amount successfully tracked particles. Further assessment of the particle imaging quality of each camera revealed a significant disparity between cameras. This was attributed to the particle light scattering intensity variations, which were highly dependent on the particle size, camera angles and different states of polarised light. Despite these challenges, an average of40,000 individual particle tracks could be reconstructed from a typical particle image density of 0.02 particles per px (and an active sensor area of 1800×2200 px2). Furthermore, the accuracy of the measurement was shown to be relatively high, with respect to PIV.
Open Access
3D Panoptic Segmentation with Unsupervised Clustering for Visual Perception in Autonomous Driving
(2021-09) Grenier, Amelie; Chermak, L
For the past decade, substantial progress has been achieved in the field of visual per ception for autonomous driving application thanks notably to the capabilities of deep learning techniques. This work aims to leverage stereovision and explore different methods, in particular unsupervised clustering approaches, to perform 3D panoptic segmentation for navigation purposes. The main contribution of this work consists in the development, test and validation of a novel framework in which geometric and semantic understanding of the scene are obtained separately at the pixel level. The combination of both for the extracted visual 2D information of the desired class provides a 3D sparse classified point cloud, which is used afterward for instance clustering. Preliminary tests of the baseline version of the framework for Vehicle objects were conducted on urban driving datasets. Results demonstrate for the first time the via bility for processing of this type of point cloud from visual data, and reveal improve ments areas. Specially, the importance of the boundary F-score in semantic seg mentation is highlighted for the first time in this application, with an increase up to 32 percentage point in this study. Additional contribution was made by applying distribution clustering as well as density based clustering for instance segmentation in a visual based 3D space representa tion. Results showed that DBSCAN was well suited for this application. As a result, it was proven that the presented framework can successfully provide genuine 3D profile map representation and localisation of vehicles in a urban environment from 2D visual information only. Furthermore, the mathematical formalisation of the link between DBSCAN’s param eter selection and camera projective geometry was presented as future work and a mean to demystify parameter selection.
Open Access
3D printing, the future of cost effective biomechanical testing
(SAFE, 2017-04-06) Franceskides, C.; Arnold, Emily; Horsfall, Ian; Clasper, J.; Tozzi, G.; Zioupos, Peter
Open Access
A 3D-collaborative wireless network: towards resilient communication for rescuing flood victims
(IEEE, 2018-04-02) Rahman, Md. Arafatur; Hasan, Md. Munirul; Asyhari, A. Taufiq; Alam Bhuiyan, Md. Zakirul
Every year, floods result in huge damage and devastation both to lives and properties all over the world. Much of this devastation and its prolonged effects result from a lack of collaboration among the rescue agents as a consequence of the lack of reliable and resilient communication platform in the disrupted and damaged environments. In order to counteract this issue, this paper aims to propose a three-dimensional (3D)- collaborative wireless network utilizing air, water and ground based communication infrastructures to support rescue missions in flood-affected areas. Through simulated Search and Rescue(SAR) activities, the effectiveness of the proposed network model is validated and its superiority over the traditional SAR is demonstrated, particularly in the harsh flood environments. The model of the 3D-Collaborative wireless network is expected to significantly assist the rescuing teams in accomplishing their task more effectively in the corresponding disaster areas.
Open Access
3D-printed coded apertures for x-ray backscatter radiography
(SPIE, 2017-09-07) Munoz, Andre Arelius Marcus; Vella, Anna; Healy, M. J. F.; Lane, David W.; Jupp, Ian; Lockley, D.
Many different mask patterns can be used for X-ray backscatter imaging using coded apertures, which can find application in the medical, industrial and security sectors. While some of these patterns may be considered to have a self-supporting structure, this is not the case for some of the most frequently used patterns such as uniformly redundant arrays or any pattern with a high open fraction. This makes mask construction difficult and usually requires a compromise in its design by drilling holes or adopting a no two holes touching version of the original pattern. In this study, this compromise was avoided by 3D printing a support structure that was then filled with a radiopaque material to create the completed mask. The coded masks were manufactured using two different methods, hot cast and cold cast. Hot casting involved casting a bismuth alloy at 80°C into the 3D printed acrylonitrile butadiene styrene mould which produced an absorber with density of 8.6 g cm-3. Cold casting was undertaken at room temperature, when a tungsten/epoxy composite was cast into a 3D printed polylactic acid mould. The cold cast procedure offered a greater density of around 9.6 to 10 g cm-3 and consequently greater X-ray attenuation. It was also found to be much easier to manufacture and more cost effective. A critical review of the manufacturing procedure is presented along with some typical images. In both cases the 3D printing process allowed square apertures to be created avoiding their approximation by circular holes when conventional drilling is used.
Open Access
5 year public health impacts of an urban greenway, Belfast, Northern Ireland: Causal Loop Diagram (Abstract no diagram)
(Oxford University Press, 2023-10-24) Hunter, R.; Garcia, L.; Clewley, Natalie; Hafezi, Mehdi; Hilton, Jeremy
Background The development of large scale urban green space infrastructure, such as a new urban greenway, provokes a cascade of changes abating a series of public health impacts, in the realms of: health, society, economy and the environment. The relationships between these factors sustain reciprocal and dynamic influence with potential to generate a virtuous cycle. However, such long-term impacts and their inter-relationships are poorly understood. Methods We aimed to co-develop a shared understanding of the public health impacts of the Connswater Community Greenway with multi-sectoral stakeholders 5 years post-implementation. Objectives were to (a) build shared understanding of the complex system influencing the public health impact of the Connswater Community Greenway, and (b) identify and explore priorities, opportunities, and actions to improve future impacts. We undertook Group Model Building workshops with people representing relevant stakeholders involved in the development and/or maintenance of the Connswater Community Greenway, and local residents living on or along the greenway. Results 23 participants were involved in the workshop included local governmental agencies, local residents, advocacy groups, private sector, and researchers. Stakeholders produced a systems map detailing the public health impacts of the Connswater Community Greenway 5 years post-implementation. Key impacts included increased in mental wellbeing, sense of community pride, increased biodiversity, increased economic investment in the local area. Participants identified a range of priority actions that, in their view, could impact and help reshape the system and influence the future impacts of the greenway. Conclusions The CLD was reflective of the various stakeholders’ experience, knowledge, perceptions, and views about the factors, and the inter-relationships between these factors, of the public health impact of the Connswater Community Greenway at 5 years post-implementation. Key messages • Systems thinking approaches can help identify the public health impacts and plausible causal pathways of green space interventions. • 5 year impacts of an urban greenway included improvements in the realms of health, wellbeing, the environment, the economy and society.
Open Access
6 Shipwreck archaeology in the past 10 years
(Cambridge University Press (CUP), 2023-12-08) Briggs, Lisa; Campbell, Peter B.
This paper reviews the trends, topics, and research directions in shipwreck archaeology over the past decade. As archaeology increasingly embraces advances in technological methods that can aid our research, the so-called ‘digital turn’, it behoves maritime archaeologists, and archaeologists more broadly, to consider how collaborative utilization of specialized fields including biomolecular archaeology, geophysics, and contemporary philosophy have spurred on a rapid modernization of our field in recent times. Archaeological research, both terrestrial and underwater, has long been a collaborative discipline. However, we argue here that difficulties in working underwater have encouraged maritime and underwater archaeologists to embrace technological developments at a rapid pace. An explicit theoretical framework and the incorporation of contemporary philosophy in the field of underwater archaeology was, until recently, largely lacking in the discipline’s discourse. The incorporation and advancement of adjacent disciplines within the field of underwater archaeology mark the most relevant changes within the shifting tides of shipwreck research.
Open Access
A two-stage classification method for improved positioning using low-cost inertial sensors
(IEEE, 2024-08-08) Maton, Dariusz; Economou, John; Galvao Wall, David; Khan, Irfan; Cooper, Robert; Ward, David; Trythall, Simon
The two-stage subtractive clustering Takagi-Sugeno (2SC-TS) method is proposed which completely replaces the established method of inertial navigation with classification models. The classifiers are designed by the subtractive clustering algorithm, an unsupervised learning method. The accuracy of the trajectories is compared against three competitive data-driven methods on three independent experimental datasets. The results show how 2SC-TS generates trajectories with approximately 20% lower positional error compared with the single-stage version (SC-TS), and halves the error produced by competitive deep learning methods. The proposed method may help improve the positioning of people and robots carrying low-cost inertial sensors.
Open Access
Accuracy of computed radiography in osteometry: a comparison of digital imaging techniques and the effect of magnification
(Elsevier, 2019-10-24) Carew, Rachael M.; Viner, Mark D.; Conlogue, Gerald J.; Márquez-Grant, Nicholas; Beckett, Sophie
Introduction Osteometric data may be obtained using digital imaging techniques, such as post-mortem computed tomography (PMCT) and digital radiography, non-invasively and without ethical objection. Osteometric data from PMCT is known to be as accurate as taking direct measurements. Digital radiography is more accessible and affordable than PMCT but is limited due to the magnification of its subjects. Objectives To investigate the viability of implementing digital radiographic techniques for measurement of long bones, and to establish whether magnification can be accurately corrected for. Materials and Methods Twenty hind pig (Sus scrofa) legs were imaged using computed radiography (CR) and PMCT, and osteometric data obtained from the digital images and 3D CT volume reconstructions. Direct measurements were taken following maceration. A calibration object was imaged using CR, to provide magnification correction factors. Results Accuracy was determined by mean absolute error (AE), giving values of 3.3 ± 2.5 mm for PMCT (MPR), 2.4 ± 1.3 mm for PMCT (3D), 11.1 ± 7.4 mm for CR (PA), and 18.3 ± 14.5 mm for CR (LAT). PMCT data was more accurate than CR data. Through applying correction for magnification, CR data became closer to the direct measurement data, and stature estimation was substantially altered. Conclusion Magnification in computed radiography affects osteometric data and resulting stature estimations. Applying correction factors may be a viable option for improving accuracy. For digital radiography to be used reliably in forensic anthropology, further empirical research is needed to validate a magnification correction method.
Open Access
ACD-G: Enhancing autonomous cyber defense agent generalization through graph embedded network representation
(International Conference on Machine Learning, 2022-07-23) Collyer, Josh; Andrew, Alex; Hodges, Duncan
The adoption of autonomous cyber defense agents within real-world contexts requires them to be able to cope with differences between their training and target environments, bridging the simulation to real gap to provide robust, generalized defensive responses. Whilst the simulation to real gap has been studied in-depth across domains such as robotics, to date there has been minimal research considering generalizability in the context of cyber defense agents and how differences in observation space could enhance agent generalizability when placed into environments that differ from the training environment. Within this paper, we propose a method of enhancing agent generalizability and performance within unseen environments by integrating a graph embedded network representation into the agent’s observation space. We then compare agent performance with and without a graph embedded network representation based observation space within a series of randomized cyber defense simulations. We find that there is a trade-off between the effectiveness of the graph embedding representation and the complexity of the graph, in terms of node count and number of edges.
Open Access
Acoustic characteristics of a multi-rotor MAV and its noise reduction technology
(Institute of Noise Control Engineering, 2016-08-21) Lu, Zhenbo; Debiasi, Marco; Khoo, Boo Cheong
The present paper is devoted to identify the acoustic characteristic of a multi-rotor MAV, and then explore effective noise reduction technologies for suppressing its high-level noise. It is found that the noise is mainly generated by the high-speed rotating propellers. Surrounding engine rotors with ducts designed to absorb their acoustic emissions is one of the methods typically used for reducing their noise. Thus two duct configurations, with non-perforated internal wall and with micro-perforated internal wall with back cavity, are designed, fabricated using 3D printing, and tested on a multi-rotor MAV. The acoustic performance of these ducts for achieving a quieter flying multi-rotor MAV are analyzed and discussed.
Open Access
AD tools and prospects for optimal AD in CFD flux Jacobian calculations
(2002-01-01T00:00:00Z) Tadjouddine, M.; Forth, Shaun A.; Pryce, J.
We consider the problem of linearising the short (approximately 100 lines of) code that defines the numerical fluxes of mass, energy and momentum across a-cell face in a finite volume compressible flow calculation. Typical of such formulations is the numerical flux due to Roe, widely used in the numerical approximation of flow fields containing moderate to strong shocks. Roe's flux takes as input 10 variables describing the flow either side of a cell face and returns as output the 5 variables for the numerical flux. We present results concerning the efficiency of derivative calculations for Roe's flux using several currently available AD tools. We also present preliminary work on deriving near optimal differentiated code using the node elimination approach. We show that such techniques, within a source transformation approach, will yield substantial gains for application code such as the Roe flux.
Open Access
AD Tools and Prospects for Optimal AD in CFD Flux Jacobian Calculations.
(2002-01-01T00:00:00Z) Tadjouddine, Mohamed; Forth, Shaun A.; Pryce, John D.
We consider the problem of linearising the short (approximately 100 lines of) code that defines the numerical fluxes of mass, energy and momentum across a cell face in a finite volume compressible flow calculation. Typical of such formulations is the numerical flux due to Roe, widely used in the numerical approximation of flow fields containing moderate to strong shocks. Roe's flux takes as input 10 variables describing the flow either side of a cell face and returns as output the 5 variables for the numerical flux. We present results concerning the efficiency of derivative calculations for Roe's flux using several currently available AD tools. We also present preliminary work on deriving near optimal differentiated code using the node elimination approach. We show that such techniques, within a source transformation approach, will yield substantial gains for application code such as the Roe flux.
Open Access
An AD-enabled optimization toolbox in LabVIEW(TM)
(2012-07-30T00:00:00Z) Gupta, Abhishek Kr.; Forth, Shaun A.
LabVIEW(TM) is a visual programming environment for data acquisition, instrument control and industrial automation. This article presents LVAD, a graphically programmed implementation of forward mode Automatic Differentiation for LabVIEW. Our results show that the overhead of using overloaded AD in LabVIEW is sufficiently low as to warrant further investigation and that, within the graphical programming environment, AD may be made reasonably user friendly. We further introduce a prototype LabVIEW Optimization Toolbox which utilizes LVAD's derivative information. Our toolbox presently contains two main LabVIEW procedures fzero and fmin for calculating roots and minima respectively of an objective function in a single variable. Two algorithms, Newton and Secant, have been implemented in each case. Our optimization package may be applied to graphically coded objective functions, not the simple string definition of functions used by many of the optimizers of LabVIEW's own optimization package.
Open Access
ADAMS model validation for an all terrain vehicle using test track data
(Sage, 2019-07-15) Kanchwala, Husain; Chatterjee, Anindya
MD ADAMS R is widely used for vehicle suspension modeling. In this paper we present modeling, simulation, and test track evaluation of an all terrain recreational vehicle. Our intention is to study the degree to which simplified ADAMS modeling actually matches human-driven vehicle response. For suspension model validation, a vehicle is generally tested on a four-post test rig and base-excitation is applied at four ground-wheel contacts. However, actual driving experience does not match idealized testing conditions. In this work the vehicle is manually driven on a variety of tracks at different speeds, and the vertical accelerations at four axle locations and four body points are measured. The same are then compared in detail against predictions from ADAMS simulation with vertical base excitation. The contribution of this paper is in identifying those aspects of the simulation results that match experiments well, and identifying possible sources for the observed mismatch, especially under more severe test conditions.
Open Access
Adaptive spatio-temporal CFAR and multiple-hypothesis tracking system
(2009-03-12T16:36:30Z) Hughes, Evan J.; Lewis, M.
This paper describes a self organising spatio-temporal radar CFAR system that uses multiple intelligent software agents to detect and adapt the processing to features in the environment. By combining both temporal and spatial data gathering sufficient samples can be collected to allow both the first and second order moments of the clutter distribution to be approximated for each cell. By gathering higher order statistics to a useful accuracy, more stable thresholds may be produced.