Helicopter main-rotor noise: Determination of source contributions using scaled model data

Acoustic data from a test of a 40 percent model MBB BO-105 helicopter main rotor are scaled to equivalent full-scale flyover cases. The test was conducted in the anechoic open test section of the German-Dutch Windtunnel (DNW). The measured data are in the form of acoustic pressure time histories and spectra from two out-of-flow microphones underneath and foward of the model. These are scaled to correspond to measurements made at locations 150 m below the flight path of a full-scale rotor. For the scaled data, a detailed analysis is given for the identification in the data of the noise contributions from different rotor noise sources. Key results include a component breakdown of the noise contributions, in terms of noise criteria calculations of a weighted sound pressure level (dBA) and perceived noise level (PNL), as functions of rotor advance ratio and descent angle. It is shown for the scaled rotor that, during descent, impulsive blade-vortex interaction (BVI) noise is the dominant contributor to the noise. In level flight and mild climb, broadband blade-turbulent wake interaction (BWI) noise is dominant due to the absence of BVI activity. At high climb angles, BWI is reduced and self-noise from blade boundary-layer turbulence becomes the most prominent

Divergence of Safety and Security

© 2020, The Author(s). Safety and security have similar goals, to provide social wellness through risk control. Such similarity has led to views of professional convergence; however, the professions of safety and security are distinct. Distinction arises from variances in concept definition, risk drivers, body of knowledge, and professional practice. This chapter explored the professional synergies and tensions between safety and security professionals, using task-related bodies of knowledge. Findings suggest that safety and security only have commonalities at the overarching abstract level. Common knowledge does exist with categories of risk management and control; however, differences are explicit. In safety, risk management focuses on hazards management, whereas security focuses on threat mitigation. Safety theories consider health impacts and accidents, whereas security crime and crime prevention. Therefore, safety and security are diverging as distinct professions

An Intensive Archeological Survey and Testing of the Proposed Lower Dorchester County Wastewater Facilities Project Area Near Summerville, South Carolina

https://scholarcommons.sc.edu/archanth_books/1174/thumbnail.jp

The efficacy of aligning lessons learnt from significant bushfire incidents to the organisational stratum

Australia\u27s bushfire seasons are expected to become longer and more severe due to the effects of climate change and an increasing population living in rural-urban fringes. Social and economic vulnerability to extreme natural hazards means that Australia’s emergency services sector plays a significant role in community safety and wellbeing. Therefore, it is important that the sector continually improves. Australia has a long history of conducting external reviews into significant bushfires. While these reviews receive good support and seek to identify relevant lessons, barriers remain that prevent these lessons from being effectively learnt. It is possible that some of these barriers exist because the stratum of work impedes the capture, codifying and adjustments to systems. This research investigated the premise that lessons learnt in the Australian emergency services sector occurs on a stratum, with different types of lessons learnt at different levels of work. Four significant independent bushfire reviews were analysed to evaluate whether specific lessons could be aligned to the stratum of work. Findings were that not all lessons apply to all levels of organisations. This supports the premise that lessons are learnt on a vertical organisational stratum; for example, some lessons were operational, others were tactical and some were strategic. It was determined that a lack of understanding of the barriers within an organisations stratum could impede the effectiveness of lessons being learnt

Epidemic predictions in an imperfect world : modelling disease spread with partial data

‘Big-data’ epidemic models are being increasingly used to influence government policy to help with control and eradication of infectious diseases. In the case of livestock, detailed movement records have been used to parametrize realistic transmission models. While livestock movement data are readily available in the UK and other countries in the EU, in many countries around the world, such detailed data are not available. By using a comprehensive database of the UK cattle trade network, we implement various sampling strategies to determine the quantity of network data required to give accurate epidemiological predictions. It is found that by targeting nodes with the highest number of movements, accurate predictions on the size and spatial spread of epidemics can be made. This work has implications for countries such as the USA, where access to data is limited, and developing countries that may lack the resources to collect a full dataset on livestock movements

Topographic determinants of foot and mouth disease transmission in the UK 2001 epidemic

Background A key challenge for modelling infectious disease dynamics is to understand the spatial spread of infection in real landscapes. This ideally requires a parallel record of spatial epidemic spread and a detailed map of susceptible host density along with relevant transport links and geographical features. Results Here we analyse the most detailed such data to date arising from the UK 2001 foot and mouth epidemic. We show that Euclidean distance between infectious and susceptible premises is a better predictor of transmission risk than shortest and quickest routes via road, except where major geographical features intervene. Conclusion Thus, a simple spatial transmission kernel based on Euclidean distance suffices in most regions, probably reflecting the multiplicity of transmission routes during the epidemic

Intelligent building systems: Security and facility professionals’ understanding of system threats,vulnerabilities and mitigation practice

Intelligent Buildings or Building Automation and Control Systems (BACS) are becoming common in buildings, driven by the commercial need for functionality, sharing of information, reduced costs and sustainable buildings. The facility manager often has BACS responsibility; however, their focus is generally not on BACS security. Nevertheless, if a BACS-manifested threat is realised, the impact to a building can be significant, through denial, loss or manipulation of the building and its services, resulting in loss of information or occupancy. Therefore, this study garnered a descriptive understanding of security and facility professionals’ knowledge of BACS, including vulnerabilities and mitigation practices. Results indicate that the majority of security and facility professionals hold a general awareness of BACS security issues, although they lacked a robust understanding to meet necessary protection. For instance, understanding of 23 BACS vulnerabilities were found to be equally critical with limited variance. Mitigation strategies were no better, with respondents indicating poor threat diagnosis. In contrast, cybersecurity and technical security professionals such as integrators or security engineering design professionals displayed a robust understanding of BACS vulnerabilities and resulting mitigation strategies. Findings support the need for greater awareness for both security management and facility professionals of BACS vulnerabilities and mitigation strategies

Corporate security career progression: A comparative study of four Australian organisations

© 2019, Springer Nature Limited. The study investigated the Corporate Security stratum of work within large Australian organisations, seeking to extract professional seating, roles, associated task complexity, career opportunity and progression ceilings as articulated through the socio-organisational literature. Two phases were applied: Phase One used online surveys distributed to participants (N = 53) across four Australian organisations, Phase Two employed semi-structured interviews and focus groups (N = 14). Findings reinforced the established literature articulation of corporate security’s roles; however, they contested the current articulation of corporate security’s executive level seating within large organisations. Instead, the study identified a Corporate Security seating with a restricted sphere of risk-based influence, along with a maximum career level at general manager. The study demonstrates an occupational corporate security ceiling, debunking the security executive belief. Corporate security was located within the technostructure group as a specialist, limiting opportunity for executive level roles or strategic influence

CONSTRAINED GENERALISED PRINCIPAL COMPONENT ANALYSIS

Abstract: Generalised Principal Component Analysis (GPCA) is a recently devised technique for fitting a multicomponent, piecewise-linear structure to data that has found strong utility in computer vision. Unlike other methods which intertwine the processes of estimating structure components and segmenting data points into clusters associated with putative components, GPCA estimates a multi-component structure with no recourse to data clustering. The standard GPCA algorithm searches for an estimate by minimising an appropriate misfit function. The underlying constraints on the model parameters are ignored. Here we promote a variant of GPCA that incorporates the parameter constraints and exploits constrained rather than unconstrained minimisation of the error function. The output of any GPCA algorithm hardly ever perfectly satisfies the parameter constraints. Our new version of GPCA greatly facilitates the final correction of the algorithm output to satisfy perfectly the constraints, making this step less prone to error in the presence of noise. The method is applied to the example problem of fitting a pair of lines to noisy image points, but has potential for use in more general multi-component structure fitting in computer vision.