44 resultados para cyber-capability
Resumo:
In recent years, there has been growing emphasis on the need to provide transparency in the costs of engineering programmes, leading to growing emphasis on Whole Life Cost (WLC) modelling techniques. This has arisen largely due to the increased interested in longer timescale projects and programmes, combined with the emergence of system-of-systems and network enabled capability concepts. This change in the implementation and management of large scale projects has necessitated the development of alternative methods of evaluating performance. This work seeks to address the shortfalls in current costing methodologies when applied to these highly flexible environments, and to propose a conceptual model for dealing with the encountered complexities. The approach has a fundamental role and potential significance in the future of whole life costing for Network Enabled Capability (NEC) but can also offer a potential paradigm shift for costing in traditional engineering environments.
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The design is described of a double layer frequency selective surface which can produce a differential phase shift of 180 ° as the wave propagates through it at normal incidence. The hand of an applied circularly polarized signal is reversed due to the 180° phase shift, and it is demonstrated that the exit circularly polarized output signal can be phase advanced or phase retarded by 180 ° upon rotation of the elements comprising the structure. This feature allows the surface to act as a spatial phase shifter. In this paper the beam steering capabilities of a 10 × 10 array of such elements are demonstrated. Here the individual elements comprising the array are rotated relative to each other in order to generate a progressive phase shift. At normal incidence the 3 dB Axial Ratio Bandwidth for LHCP to RHCP conversion is 5.3% and the insertion loss was found to be -2.3 dB, with minimum axial ratio of 0.05 dB. This array is shown to be able to steer a beam from -40 ° to +40 ° while holding axial ratio at the pointing angle to below 4 dB. The measured radiation patterns match the theoretical calculation and full-wave simulation results. © 2010 IEEE.
Resumo:
Reactive power has become a vital resource in modern electricity networks due to increased penetration of distributed generation. This paper examines the extended reactive power capability of DFIGs to improve network stability and capability to manage network voltage profile during transient faults and dynamic operating conditions. A coordinated reactive power controller is designed by considering the reactive power capabilities of the rotor-side converter (RSC) and the grid-side converter (GSC) of the DFIG in order to maximise the reactive power support from DFIGs. The study has illustrated that, a significant reactive power contribution can be obtained from partially loaded DFIG wind farms for stability enhancement by using the proposed capability curve based reactive power controller; hence DFIG wind farms can function as vital dynamic reactive power resources for power utilities without commissioning additional dynamic reactive power devices. Several network adaptive droop control schemes are also proposed for network voltage management and their performance has been investigated during variable wind conditions. Furthermore, the influence of reactive power capability on network adaptive droop control strategies has been investigated and it has also been shown that enhanced reactive power capability of DFIGs can substantially improve the voltage control performance.
Resumo:
The increased complexity and interconnectivity of Supervisory Control and Data Acquisition (SCADA) systems in the Smart Grid has exposed them to a wide range of cyber-security issues, and there are a multitude of potential access points for cyber attackers. This paper presents a SCADA-specific cyber-security test-bed which contains SCADA software and communication infrastructure. This test-bed is used to investigate an Address Resolution Protocol (ARP) spoofing based man-in-the-middle attack. Finally, the paper proposes a future work plan which focuses on applying intrusion detection and prevention technology to address cyber-security issues in SCADA systems.
Resumo:
Greater complexity and interconnectivity across systems embracing Smart Grid technologies has meant that cyber-security issues have attracted significant attention. This paper describes pertinent cyber-security requirements, in particular cyber attacks and countermeasures which are critical for reliable Smart Grid operation. Relevant published literature is presented for critical aspects of Smart Grid cyber-security, such as vulnerability, interdependency, simulation, and standards. Furthermore, a preliminary study case is given which demonstrates the impact of a cyber attack which violates the integrity of data on the load management of real power system. Finally, the paper proposes future work plan which focuses on applying intrusion detection and prevention technology to address cyber-security issues. This paper also provides an overview of Smart Grid cyber-security with reference to related cross-disciplinary research topics.
Resumo:
The safety of our food is an essential requirement of society. One well-recognised threat is that of chemical contamination of our food, where low-molecular-weight compounds such as biotoxins, drug residues and pesticides are present. Low-cost, rapid screening procedures are sought to discriminate the suspect samples from the population, thus selecting only these to be forwarded for confirmatory analysis. Many biosensor assays have been developed as screening tools in food contaminant analysis, but these tend to be electrochemical, fluorescence or surface plasmon resonance based. An alternative approach is the use of biolayer interferometry, which has become established in drug discovery and life science studies but is only now emerging as a potential tool in the analysis of food contaminants. A biolayer interferometry biosensor was assessed using domoic acid as a model compound. Instrument repeatability was tested by simultaneously producing six calibration curves showing replicate repeatability (n = 2) ranging from 0.1 to 6.5 % CV with individual concentration measurements (n = 12) ranging from 4.3 to 9.3 % CV, giving a calibration curve midpoint of 7.5 ng/ml (2.3 % CV (n = 6)). Reproducibility was assessed by producing three calibration curves on different days, giving a midpoint of 7.5 ng/ml (3.4 %CV (n = 3)). It was further shown, using assay development techniques, that the calibration curve midpoint could be adjusted from 10.4 to 1.9 ng/ml by varying assay parameters before the simultaneous construction of three calibration curves in matrix and buffer. Sensitivity of the assay compared favourably with previously published biosensor data for domoic acid. © 2013 Springer-Verlag Berlin Heidelberg.
Resumo:
In today’s world, supply chains are becoming more complex and more vulnerable due to increased interdependency of multiple threats. This paper investigates the vulnerability sources in context of sustainable supply chain in order to minimize the impact of uncertain events. The capability-based perspective is discussed in this paper to understand the strategies to improve the resilience of the supply chain. Paper argues that organisations must think beyond their boundaries to accumulate or integrate network resources and develop critical collaborative capabilities across the supply chain to successfully encounter future disruptions.
Resumo:
In this short paper, we present an integrated approach to detecting and mitigating cyber-attacks to modern interconnected industrial control systems. One of the primary goals of this approach is that it is cost effective, and thus whenever possible it builds on open-source security technologies and open standards, which are complemented with novel security solutions that address the specific challenges of securing critical infrastructures.
Resumo:
Invited talk, representing the Royal Society
Resumo:
As part of any drilling cuttings pile removal process the requirement for monitoring the release of contaminants into the marine environment will be critical. Traditional methods for such monitoring involve taking samples for laboratory analysis. This process is time consuming and only provides data on spot samples taken from a limited number of locations and time frames. Such processes, therefore, offer very restricted information. The need for improved marine sensors for monitoring contaminants is established. We report here the development and application of a multi-capability optical sensor for the real-time in situ monitoring of three key marine environmental and offshore/oil parameters: hydrocarbons, synthetic-based fluids and heavy metal concentrations. The use of these sensors will be a useful tool for real-time in situ environmental monitoring during the process of decommissioning offshore structures. Multi-capability array sensors could also provide information on the dispersion of contamination from drill cuttings piles either while they are in situ or during their removal.