Cranfield Defence and Security

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Open Access
3D printing, the future of cost effective biomechanical testing
(SAFE, 2017-04-06) Franceskides, Constantinos ; 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, Matthew 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
A cognitive-based ISAR system for spectral compatibility applications
(IEEE, 2024-11-11) Rosamilia, Massimo; Aubry, Augusto; Balleri, Alessio; De Maio, Antonio; Martorella, Marco
This paper proposes and analyzes the concept of a cognitive inverse synthetic aperture radar (ISAR) ensuring spectral compatibility in crowded electromagnetic environments. In such a context, cognitive radar system alternates between a perception stage, recognizing possible emitters in its frequency range, and an action stage, synthesizing and transmitting a tailored radar waveform to achieve the desired task while guaranteeing the spectral coexistence with overlaid emitters. The perception stage is carried out by an electronic support measurement system (ESM) that senses the environment and extracts relevant spectral parameters. The action stage employs a tailored signal design process, synthesizing a radar waveform with bespoke spectral notches, enabling ISAR imaging over a wide spectral bandwidth without interfering with the other radio frequency (RF) systems. A key enabling technology for the proposed application is the compressed sensing (CS) framework, allowing accurate ISAR imaging even with missing data in the frequency domain (induced by spectral notches) and in the slow-time dimension (enabling the system to perform additional RF activities). The capabilities of the proposed system are assessed exploiting a dataset of drone measurements in the frequency band [13, 15] GHz. The results highlight the effectiveness of the proposed system to enable the spectral compatibility while delivering high-quality ISAR images.
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
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
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.
Open Access
Additively manufactured (3DP) thermite structures vs conventionally manufactured equivalents
(IPSUSA Seminars, 2022-07-14) McGee, Christine; Vrcelj, Ranko
Research into additive manufacturing (AM) has been steadily expanding over the past five decades. Where once only polymeric materials could be reliably printed, AM has been adapted to print with a range of materials such as biological, metallic, ceramic and even foodstuffs. The advantages of manufacturing in an additive manner include; a) a layer-by-layer approach allows the creation of architecturally complex structures, b) a reduction in weight, c) lessening of waste and d) the ability to create parts that that are otherwise difficult or too costly to produce. Pyrotechnic materials, including thermites, are used in a wide range of commercial and defence applications. However, hazards present during manufacturing and storage have resulted in major accidents around the world, with subsequent loss of life and in some cases loss of public infrastructure. AM, using a dry powder printing technique means that parts can be manufactured on demand, reducing the need for storage of large volumes of fully formed products or mixes, thus increasing the safety over lifetime of a product. The performance of pyrotechnics materials is dependent on a number of properties, including chemical composition, thermodynamic properties and physical form. In combination with composition, architecture could be utilised to understand and control these properties. A bespoke printer capable of additively manufacturing pyrotechnic materials has been constructed with the aim to explore this research area. In this presentation, we compare the burn rates of AM thermites and compare them to conventionally fabricated compositions and discuss the effects of the print parameters and confinement. We conclude with the results from the burning of AM thermite structures and compare their performance with conventionally prepared equivalent thermite examples.
Open Access
Advanced cognitive networked radar surveillance
(IEEE, 2021-06-18) Jahangir, Mohammed; Baker, Chris J.; Antoniou, Michail; Griffin, Benjamin; Balleri, Alessio; Money, David; Harman, Stephen
The concept of a traditional monostatic radar with co-located transmit and receive antennas naturally imposes performance limits that can adversely impact applications. Using a multiplicity of transmit and receive antennas and exploiting spatial diversity provides additional degrees of design freedom that can help overcome such limitations. Further, when coupled with cognitive signal processing, such advanced systems offer significant improvement in performance over their monostatic counterparts. This will also likely lead to new applications for radar sensing. In this paper we explore the fundamentals of multistatic network radar highlighting both potential and constraints whilst identifying future research needs and applications. Initial experimental results are presented for a 2-node networked staring radar.
Open Access
Advanced detection and tracking in medium PRF radar
(2009-03-12T15:51:08Z) Hughes, Evan J.; Lewis, M.
This paper describes an improved method of target tracking particularly applicable to littoral environments where a wide range of clutter characteristics are present. A light weight multiple hypothesis tracker based on multiple intelligent software agents is presented.
Open Access
Aero-whisker for the measurement of aircraft flight speed and angle of attack in compressible flow conditions
(AIAA, 2023-06-08) Debiasi, Marco; Atkinson, Kevin; Saddington, Alistair J.; Finnis, Mark
A whisker-like device has been designed and tested that simultaneously measures the speed and the direction of a flow in which it protrudes. The device consists of a thin cylindrical probe longer than the thickness of the local boundary layer whose aerodynamic drag produces a moment at its base which is measured by a solid-state torque transducer. With proper calibration, the orthogonal components of the moment can be used to measure the speed and the direction of the flow. Measurements have been performed in a wind tunnel to validate the design at flow velocities ranging from Mach 0.15 to Mach 0.87 and for flow angles relative to the probe ranging from -88° to +88°. The results obtained indicate that the aero-whisker is capable to accurately measure the Mach number and direction of the flow with potential for further optimization for aircraft applications.
Open Access
Altered andragogy: lessons from lockdown for systems engineering education
(The International Academic Forum (IAFOR), 2021-09-06) Barker, Stephen G.; Smith, Jeremy D.
Systems Engineering (SE) is a largely interactive and applied discipline which has been mainly taught via face-to-face tuition. The move to online-only teaching due to the 2020 coronavirus pandemic thus posed significant challenges for SE education. The andragogical strategy involved had to be rethought and redesigned such that key precepts of student learning could be maintained in a way that preserved the depth, intricacy, and richness of the SE discipline. The interdisciplinary approach adopted involved combining a constructivist viewpoint with integrated collaborative and reflective activities, based around inquiry-based learning to facilitate online learning at distance. This pedagogical construct relied on a multidisciplinary and iterative approach to curriculum and module delivery, employing multiple methods to redesign the teaching approach to ‘chunk’ material into sets that were more readily deliverable in short bursts, and more digestible without face-to-face interaction. This took in revisions to the traditional pedagogical approach to learning, and blended short live online sessions with self-paced tasks, supported by Q&A sessions and ‘thought bursts’ of key information to summarise key learning points. Learning technology and software tools were used to facilitate and promote interactive and group workshops, which was particularly challenging but proved useful in bridging generational gaps and preferences for certain learning styles. This paper details the andragogical approach taken to wholly online distance learning for SE, reflecting on how successful it was both initially and as it evolved. It also considers how future learning can be successfully facilitated, incorporating the pedagogical lessons learned from the last twelve months.
Open Access
An experimental method of determining explosive equivalency when scaled distance approaches zero
(International Society of Explosives Engineers, 2024-01-01) Alford, Roland; Hazael, Rachael; Critchley, Richard
The ability to compare explosives is fundamental. Numerous methods are used and while simple conversion factors are often used, the use of TNT Equivalency (TNTe) is not a simple subject as explosives exhibit very different equivalencies depending on whether the pressure or impulse are being considered as well as other conditions. The scaled distance has been found to have a significant effect on the TNTe but due to the difficulty of taking measurements at very close ranges, no TNTe have been quoted for charges in direct contact (Z=0). This paper describes the use of a ballistic pendulum to measure the impulse from contact charges and presents some surprising results that require a two-stage propulsion, as originally described by Backofen, to be explained.
Open Access
Analysis and exploitation of complex SAR phenomena produced from vibrating targets
(Institute of Acoustics, 2018-12-31) Corbett, Brandon; Andre, Daniel; Muff, D.; Finnis, Mark V.; Blacknell, D.
Open Access
An analysis of Hotmail artefacts in Firefox 9
(2012-09-06T00:00:00Z) David, A.; Hargreaves, C. J.
Webmail is a convenient way of accessing emails via a web browser on any computer connected to the Internet and it has gained popularity amongst Internet users. Many webmail service providers offer a free email service where users can set up an email account online by supplying their personal details and choosing a preferred username. Email artefacts such as usernames, aliases, message subject and body may be useful in a digital investigation and thus require recovery and analysis. Unlike client based email software where a user’s messages are stored locally on the hard disk, webmail messages are stored remotely on the webmail provider’s servers, potentially making it difficult for digital investigators to obtain relevant artefacts. However, since webmail is accessed through a browser and browsers leave their own artefacts, it may be possible to recover artefacts that may be useful in investigations. This paper discusses certain artefacts that can be left on a user’s hard disk as a result of using Hotmail. For instance, artefacts that could be used to infer when an email account was created and the details supplied at set up; details of exchanged emails such as who a user sent an email to, when the email was sent and whether it was replied to; full or partial contents of the email; details of contacts that had been added, edited, deleted or restored by the account user. The experiments are carried out on Hotmail using Firefox 9 and involve the analysis of the various file formats used by Firefox as well as their evidential value. The research also involves a multi-tool analysis technique which is necessary due to the differences in the format of artefacts recovered and to ensure the accurate interpretation of data. A hex editor, SQLite analysis tool, standalone JSON viewer, and a cache analysis tool are some of the tools identified as useful and are discussed in this paper.
Open Access
An analysis of the structure and behaviour of the Windows 7 operating system thumbnail cache
(University of Strathclyde, Glasgow, 2011-06-28) Morris, Sarah; Chivers, Howard
Operating systems such as Windows 7 implement a thumbnail cache structure to store visual thumbnails and associated metadata. There is no standard implementation of a thumbnail cache or its functions, which has led developers to implement their own structures and behaviour. The artefacts present within a thumbnail cache are of interest to a forensic analyst as they can provide information on files within the system which may be of use to the investigation. This research investigates the structure and behaviour of the thumbnail cache implemented in Windows 7 and shows that as well as storing information relating to visual thumbnails the cache also stores the names of networked computers, GUIDs relating to system artefacts and allocated drive letter information. It also shows that due to the behaviour of the cache, information such as records relating to files which are no longer on the system may be available, proving interesting forensic evidence.
Open Access
Application of spectral and spatial indices for specific class identification in Airborne Prism EXperiment (APEX) imaging spectrometer data for improved land cover classification
(SPIE, 2016-09) Kallepalli, Akhil; Kumar, Arvind; Khoshelham, K.; James, David B.
Hyperspectral remote sensing's ability to capture spectral information of targets in very narrow bandwidths gives rise to many intrinsic applications. However, the major limiting disadvantage to its applicability is its dimensionality, known as the Hughes Phenomenon. Traditional classification and image processing approaches fail to process data along many contiguous bands due to inadequate training samples. Another challenge of successful classification is to deal with the real world scenario of mixed pixels i.e. presence of more than one class within a single pixel. An attempt has been made to deal with the problems of dimensionality and mixed pixels, with an objective to improve the accuracy of class identification. In this paper, we discuss the application of indices to cope with the disadvantage of the dimensionality of the Airborne Prism EXperiment (APEX) hyperspectral Open Science Dataset (OSD) and to improve the classification accuracy using the Possibilistic c–Means (PCM) algorithm. This was used for the formulation of spectral and spatial indices to describe the information in the dataset in a lesser dimensionality. This reduced dimensionality is used for classification, attempting to improve the accuracy of determination of specific classes. Spectral indices are compiled from the spectral signatures of the target and spatial indices have been defined using texture analysis over defined neighbourhoods. The classification of 20 classes of varying spatial distributions was considered in order to evaluate the applicability of spectral and spatial indices in the extraction of specific class information. The classification of the dataset was performed in two stages; spectral and a combination of spectral and spatial indices individually as input for the PCM classifier. In addition to the reduction of entropy, while considering a spectral-spatial indices approach, an overall classification accuracy of 80.50% was achieved, against 65% (spectral indices only) and 59.50% (optimally determined principal components
Open Access
Applying Performance Measurement to Safeguard Budgets: Qualitative and Quantitative Measurement of Electronic Journal Packages.
(2014-08-23) Killick, SA; Steve, Hiller; Martha, Kyrillidou; Angela, Pappalardo; Jim, Self; Amy, Yeager
In the current financial climate effective performance measurement has become a vital tool for library managers. This paper presents a case study from Cranfield University in the United Kingdom on qualitative and quantitative techniques employed to measure the performance of electronic resources. Cranfield University Libraries have developed a process for systematic and sustainable assessment of its electronic resources. Initially focused on electronic journal packages, the process enables the library service to demonstrate smart procurement to key stakeholders. Quantitative key performance indicators were developed based on the COUNTER usage statistics, internal financial information and population data. A systematic process for capturing, storing and analyzing usage data was developed. In order to make the process sustainable a template was created to calculate all derived metrics and present the key performance indicators in a format suitable for senior stakeholders. It was soon discovered that quantitative measures alone would not enable the library to fully assess the performance of the collection. Through academic liaison interviews the library staff embarked upon a process to capture the qualitative information pertinent to the resources. A template was used for each package documenting who is using the resource, how they are using it, and what impact any cancellation would have on the strategic goals of the organization. The combined approach of both quantitative metrics and qualitative factors enabled the library to effectively demonstrate the value of the electronic journal packages. The results were successfully used to lobby against a proposed resources cut, safeguarding the electronic journals from budget reductions. Lessons learnt from the development of the process along with next steps are presented. This paper will be of interest to those involved in library collection management and library staff with a remit in performance measurement. In particular it may assist the development of deeper understanding of measuring the value and impact of electronic library collections, and will also therefore be of value to all those concerned with library strategy and development.
Open Access
The Asia Pivot as a Strategy of Foreign Policy: A Source of Peace or a Harbinger of Conflict?
(International Studies Association, 2017-06) Southgate, L.
The Obama Administration’s Asia Pivot strategy has sought to strengthen the United States’ (US) bilateral security alliances in Asia, intensify working relationships with regional states and the US, and boost regional trade and investment. This paper investigates whether the Obama administration’s Asia Pivot has fulfilled its strategy of enhancing peace and cooperation in the Pacific, or whether it has in fact magnified the potential for regional conflict. In doing so, it seeks an answer to the following, interrelated questions: What have been the costs and benefits of the Asia Pivot strategy for the United States and regional actors? Is the Asia Pivot strategy an example of foreign policy success, or failure? For the purpose of this paper, foreign policy is understood as a multidimensional concept that takes into account degree of goal attainment, the costs to the user; the costs to the target; and an identification of who has most at stake in the issue. In doing so it will argue that the costs of the Asia Pivot strategy have largely outweighed the benefits, thus having a negative impact on peace in the Asia Pacific.

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