Levels of abstraction in human supervisory control teams

This paper aims to report a study into the levels of abstraction hierarchy (LOAH) in two energy distribution teams. The original proposition for the LOAH was that it depicted five levels of system representation, working from functional purpose through to physical form to determine causes of a malfunction, or from physical form to functional purpose to determine the purpose of system function. The LOAH has been widely used throughout human supervisory control research to explain individual behaviour. The research seeks to focus on the application the LOAH to human supervisory control teams in semi-automated “intelligent” systems

Testing Hollnagel's contextual control mod

Please contact publisher for further reprinting or re-useThis article sets out to test the hypothetical COtext and COntrol Model (COCOM) developed by Hollnagel (1993). Essentially, Hollnagel develops the argument that team behavior should be analyzed at a macro, rather than micro, level. He proposes 4 principal models of team activity: strategic, tactical, opportunistic, and scrambled. These modes of team behavior vary in terms of the degree of forward planning (highest in the strategic mode) and reactivity to the environment (highest in the scrambled mode). He further hypothesizes a linear progression through the modes from strategic to tactical to opportunistic to scrambled, depending on context, and vice versa. To test the COCOM model, we placed teams of people in a simulated energy distribution system. Our results confirm Hollnagel's hypothesized model in 2 main ways. First, we show that the team behavior could be categorized reliably into the 4 control modes and this provided a useful way of distinguishing between experimental conditions. Second, the progression between control modes conformed to the linear progression as predicted. This research provided the first independent test of the COCOM model and lends empirical support to the hypotheses

Flexural fatigue performance of CFRP prestressed concrete poles

Carbon fibre reinforced polymer (CFRP) prestressed concrete poles offer a durable, light-weight alternative to conventional steel-reinforced or prestressed concrete poles. In particular, the corrosion resistance of the CFRP tendons can result in lower maintenance costs and a reduction in the required concrete cover. For lighting poles used in pedestrian or low-trafficked areas, wind loading represents a dominant load case. The wind acts as a transient force and can blow from any direction. It is therefore of interest to investigate how CFRP prestressed lighting poles perform under repeated cyclic loads and/or load reversals. Experiments were carried out on pole sections tested horizontally. These included a static control test and a conventional fatigue test where a cyclic load was applied in a downwards direction for 2 million cycles. Three further fatigue tests where the load direction changed, either after a defined number of cycles or within a load cycle, were also conducted. It was found that all the poles performed adequately for 1–2 million cycles of loading and that the majority of any deflection increases occurred within the first 50,000 cycles. It is believed that repeated cyclic loading may have increased the tendon debonding at the crack locations. Localised debonding potentially relieves the stress in the outermost tendon layer which delays the onset of failure and allows the inner tendon layers to take up further stress thus leading to a higher load carrying capacity. Loading orientation reversal from a downwards to an upwards direction within a loading cycle did not result in a greater stiffness degradation when compared to the other fatigue tests. The initial findings suggest that in-service cyclic loading and load reversals will not be detrimental to the performance of CFRP prestressed concrete poles. This is the accepted version of an original publication available here: http://multi-science.metapress.com/content/w842084116q73104/?genre=article&id=doi%3a10.1260%2f1369-4332.15.4.57

Virtuality in human supervisory control: Assessing the effects of psychological and social remoteness

Virtuality would seem to offer certain advantages for human supervisory control. First, it could provide a physical analogue of the 'real world' environment. Second, it does not require control room engineers to be in the same place as each other. In order to investigate these issues, a low-fidelity simulation of an energy distribution network was developed. The main aims of the research were to assess some of the psychological concerns associated with virtual environments. First, it may result in the social isolation of the people, and it may have dramatic effects upon the nature of the work. Second, a direct physical correspondence with the 'real world' may not best support human supervisory control activities. Experimental teams were asked to control an energy distribution network. Measures of team performance, group identity and core job characteristics were taken. In general terms, the results showed that teams working in the same location performed better than team who were remote from one another

Rossby wave dynamics of the North Pacific extra-tropical response to El Niño: importance of the basic state in coupled GCMs

The extra-tropical response to El Nino in a "low" horizontal resolution coupled climate model, typical of the Intergovernmental Panel on Climate Change fourth assessment report simulations, is shown to have serious systematic errors. A high resolution configuration of the same model has a much improved response that is similar to observations. The errors in the low resolution model are traced to an incorrect representation of the atmospheric teleconnection mechanism that controls the extra-tropical sea surface temperatures (SSTs) during El Nino. This is due to an unrealistic atmospheric mean state, which changes the propagation characteristics of Rossby waves. These erroneous upper tropospheric circulation anomalies then induce erroneous surface circulation features over the North Pacific. The associated surface wind speed and direction errors create erroneous surface flux and upwelling anomalies which finally lead to the incorrect extra-tropical SST response to El Nino in the low resolution model. This highlights the sensitivity of the climate response to a single link in a chain of complex climatic processes. The correct representation of these processes in the high resolution model indicates the importance of horizontal resolution in resolving such processes

Aberrant phenotype in human endothelial cells of diabetic origin: Implications for saphenous vein graft failure?

Type 2 diabetes (T2DM) confers increased risk of endothelial dysfunction, coronary heart disease, and vulnerability to vein graft failure after bypass grafting, despite glycaemic control. This study explored the concept that endothelial cells (EC) cultured from T2DM and nondiabetic (ND) patients are phenotypically and functionally distinct. Cultured human saphenous vein-(SV-) EC were compared between T2DM and ND patients in parallel. Proliferation, migration, and in vitro angiogenesis assays were performed; western blotting was used to quantify phosphorylation of Akt, ERK, and eNOS. The ability of diabetic stimuli (hyperglycaemia, TNF-α, and palmitate) to modulate angiogenic potential of ND-EC was also explored. T2DM-EC displayed reduced migration (30%) and angiogenesis (40%) compared with ND-EC and a modest, nonsignificant trend to reduced proliferation. Significant inhibition of Akt and eNOS, but not ERK phosphorylation, was observed in T2DM cells. Hyperglycaemia did not modify ND-EC function, but TNF-α and palmitate significantly reduced angiogenic capacity (by 27% and 43%, resp.), effects mimicked by Akt inhibition. Aberrancies of EC function may help to explain the increased risk of SV graft failure in T2DM patients. This study highlights the importance of other potentially contributing factors in addition to hyperglycaemia that may inflict injury and long-term dysfunction to the homeostatic capacity of the endothelium

Management of Septated Malignant Pleural Effusions

Purpose of Review: We review recent studies of patients with septated malignant pleural effusions, to understand what the clinical implications for patients are and what evidence-based methods should be used to manage these effusions. Recent Findings: Fibrinolytics improve effusion size assessed radiologically in patients with a chest drain inserted for septated malignant pleural effusions but this does not translate into an improvement in breathlessness relief or pleurodesis success. Fibrinolytics have also been used in patients with septated effusions associated with indwelling pleural catheters, but dyspnoea relief has not been assessed in this population. Patients with septated effusions or extensive adhesions appear to have a worse prognosis. Summary: Patients with septated malignant pleural effusions have a poor prognosis and do not gain clinical benefit from fibrinolytics via chest drain. The role of fibrinolytics for septated effusions associated with indwelling pleural catheters requires further study

Creating Awareness of Sleep-Wake Hours by Gamification

This book constitutes the refereed proceedings of the 11th International Conference on Persuasive Technology, PERSUASIVE 2016, held in Salzburg, Austria, in April 2016

ARIADNE - A novel optical LArTPC: technical design report and initial characterisation using a secondary beam from the CERN PS and cosmic muons

ARIADNE is a 1-ton (330 kg fiducial mass) dual-phase liquid argon (LAr) time projection chamber (TPC) featuring a novel optical readout. Four electron-multiplying charge-coupled device (EMCCD) cameras are mounted externally, and these capture the secondary scintillation light produced in the holes of a thick electron gas multiplier (THGEM). Track reconstruction using this novel readout approach is demonstrated. Optical readout has the potential to be a cost effective alternative to charge readout in future LArTPCs. In this paper, the technical design of the detector is detailed. Results of mixed particle detection using a secondary beam from the CERN PS (representing the first ever optical images of argon interactions in a dual-phase LArTPC at a beamline) and cosmic muon detection at the University of Liverpool are also presented.Comment: 58 pages, 40 figures. Changes from previous version based on pre-publication review: improved quality of various figures, improved clarity of some definitions and reduced longer sentences for better readability, fixed typos and formatting error