Obstacle crossing during locomotion: Visual exproprioceptive information is used in an online mode to update foot placement before the obstacle but not swing trajectory over it

YesAlthough gaze during adaptive gait involving obstacle crossing is typically directed two or more steps ahead, visual information of the swinging lower-limb and its relative position in the environment (termed visual exproprioception) is available in the lower visual field (lvf). This study determined exactly when lvf exproprioceptive information is utilised to control/update lead-limb swing trajectory during obstacle negotiation. 12 young participants negotiated an obstacle wearing smart-glass goggles which unpredictably occluded the lvf for certain periods during obstacle approach and crossing. Trials were also completed with lvf occluded for the entirety of the trial. When lvf was occluded throughout, footplacement distance and toe-clearance became significantly increased; which is consistent with previous work that likewise used continuous lvf occlusion. Both variables were similarly affected by lvf occlusion from instant of penultimate-step contact, but both were unaffected when lvf was occluded from instant of final-step contact. These findings suggest that lvf (exproprioceptive) input is typically used in an online manner to control/update final foot-placement, and that without such control, uncertainty regarding foot placement causes toe-clearance to be increased. Also that lvf input is not normally exploited in an online manner to update toe-clearance during crossing: which is contrary to what previous research has suggested

Run-time detection of faults in autonomous mobile robots based on the comparison of simulated and real robot behaviour

© 2014 IEEE. This paper presents a novel approach to the run-time detection of faults in autonomous mobile robots, based on simulated predictions of real robot behaviour. We show that although simulation can be used to predict real robot behaviour, drift between simulation and reality occurs over time due to the reality gap. This necessitates periodic reinitialisation of the simulation to reduce false positives. Using a simple obstacle avoidance controller afflicted with partial motor failure, we show that selecting the length of this reinitialisation time period is non-trivial, and that there exists a trade-off between minimising drift and the ability to detect the presence of faults

Underuse of coronary revascularization procedures in patients considered appropriate candidates for revascularization.

Background: Ratings by an expert panel of the appropriateness of treatments may offer better guidance for clinical practice than the variable decisions of individual clinicians, yet there have been no prospective studies of clinical outcomes. We compared the clinical outcomes of patients treated medically after angiography with those of patients who underwent revascularization, within groups defined by ratings of the degree of appropriateness of revascularization in varying clinical circumstances.Methods: This was a prospective study of consecutive patients undergoing coronary angiography at three London hospitals. Before patients were recruited, a nine-member expert panel rated the appropriateness of percutaneous transluminal coronary angioplasty (PTCA) and coronary-artery bypass grafting (CABG) on a nine-point scale (with 1 denoting highly inappropriate and 9 denoting highly appropriate) for specific clinical indications. These ratings were then applied to a population of patients with coronary artery disease. However, the patients were treated without regard to the ratings. A total of 2552 patients were followed for a median of 30 months after angiography.Results: Of 908 patients with indications for which PTCA was rated appropriate (score, 7 to 9), 34 percent were treated medically; these patients were more likely to have angina at follow-up than those who underwent PTCA (odds ratio, 1.97; 95 percent confidence interval, 1.29 to 3.00). Of 1353 patients with indications for which CABG was considered appropriate, 26 percent were treated medically; they were more likely than those who underwent CABG to die or have a nonfatal myocardial infarction - the composite primary outcome (hazard ratio, 4.08; 95 percent confidence interval, 2.82 to 5.93) - and to have angina (odds ratio, 3.03; 95 percent confidence interval, 2.08 to 4.42). Furthermore, there was a graded relation between rating and outcome over the entire scale of appropriateness (P for linear trend = 0.002).Conclusions: On the basis of the ratings of the expert panel, we identified substantial underuse of coronary revascularization among patients who were considered appropriate candidates for these procedures. Underuse was associated with adverse clinical outcomes. (N Engl J Med 2001;344:645-54.) Copyright (C) 2001 Massachusetts Medical Society

Perforated Plates as Passive Mitigation Systems

This paper presents the results of tests on fully-clamped circular plates subjected to blastloading directed down a tube. Four series of tests were performed. In one set of experiments,the blast wave was allowed to progress unhindered down the tube to impinge upon the plate,and in the other tests, perforated plates were placed in the path of the blast wave to hinderprogression down the tube, disrupting the blast and absorbing some of the kinetic energy.Results of the tests indicate that the perforated plates can be used as a form of passive mitigation

UK perspective on the changing landscape of non-invasive cardiac testing.

Objective: To document UK rates of exercise treadmill testing, functional stress testing and CT coronary angiography (CTCA). Specific aims were to determine how rates have changed in the context of changing guideline recommendations within the UK and to identify regional inequalities in the utilisation of testing modalities. Secondary objectives were to compare these trends with national data on revascularisation. Methods: 159 acute National Health Service trusts were served Freedom of Information (FOI) requests to provide total numbers of CTCA and functional imaging tests for each financial year from 2011-2012 to 2016-2017. Results: The FOI requests yielded data from 88% of Trusts, increasing from 81.9% in 2011-2012% to 92.1% in 2016-2017. Exercise treadmill tests (ETTs) were performed by over 97% of Trusts. ETT was the most commonly performed diagnostic test in the UK across the study period despite declining by 8.4%. Utilisation of non-invasive stress imaging tests increased by 80.9% during the same period. Myocardial perfusion scintigraphy and stress echocardiography increased by 25.8% and 73.9%, respectively. The 268% increase in CTCA scans was yet greater. Trends in test utilisation during the study period showed important regional differences between devolved nations. Comparably, only small changes in rates of invasive coronary angiography and revascularisation have been reported during the study period. Conclusion: Non-invasive imaging in UK Trusts has increased substantially since 2010 with only a small decline in use of the ETT and minimal changes in rates of invasive coronary angiography and revascularisation in the same time period

The need for combining implicit and explicit communication in cooperative robotic systems

As the number of robots used in warehouses and manufacturing increases, so too does the need for robots to be able to manipulate objects, not only independently, but also in collaboration with humans and other robots. Our ability to effectively coordinate our actions with fellow humans encompasses several behaviours that are collectively referred to as joint action, and has inspired advances in human-robot interaction by leveraging our natural ability to interpret implicit cues. However, our capacity to efficiently coordinate on object manipulation tasks remains an advantageous process that is yet to be fully exploited in robotic applications. Humans achieve this form of coordination by combining implicit communication (where information is inferred) and explicit communication (direct communication through an established channel) in varying degrees according to the task at hand. Although these two forms of communication have previously been implemented in robotic systems, no system exists that integrates the two in a task-dependent adaptive manner. In this paper, we review existing work on joint action in human-robot interaction, and analyse the state-of-the-art in robot-robot interaction that could act as a foundation for future cooperative object manipulation approaches. We identify key mechanisms that must be developed in order for robots to collaborate more effectively, with other robots and humans, on object manipulation tasks in shared autonomy spaces

Towards fault diagnosis in robot swarms : An online behaviour characterisation approach

Although robustness has been cited as an inherent advantage of swarm robotics systems, it has been shown that this is not always the case. Fault diagnosis will be critical for future swarm robotics systems if they are to retain their advantages (robustness, flexibility and scalability). In this paper, existing work on fault detection is used as a foundation to propose a novel approach for fault diagnosis in swarms based on a behavioural feature vector approach. Initial results show that behavioural feature vectors can be used to reliably diagnose common electro-mechanical fault types in most cases tested

A Time-Domain Analysis of Intracardiac Electrograms for Arrhythmia Detection

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73045/1/j.1540-8159.1991.tb05116.x.pd