Ergonomics of the Operative Field in Paediatric Minimal Access Surgery

Imperial Users onl

Toolbox of Countermeasures for Rural Two-Lane Curves, June 2012

The Federal Highway Administration (FHWA) estimates that 58 percent of roadway fatalities are lane departures, while 40 percent of fatalities are single-vehicle run-off-road (SVROR) crashes. Addressing lane-departure crashes is therefore a priority for national, state, and local roadway agencies. Horizontal curves are of particular interest because they have been correlated with increased crash occurrence. This toolbox was developed to assist agencies address crashes at rural curves. The main objective of this toolbox is to summarize the effectiveness of various known curve countermeasures. While education, enforcement, and policy countermeasures should also be considered, they were not included given the toolbox focuses on roadway-based countermeasures. Furthermore, the toolbox is geared toward rural two-lane curves. The research team identified countermeasures based on their own research, through a survey of the literature, and through discussions with other professionals. Coverage of curve countermeasures in this toolbox is not necessarily comprehensive. For each countermeasure covered, this toolbox includes the following information: description, application, effectiveness, advantages, and disadvantages

Perception Threshold for Pressure by a Soft Textile Actuator

Electroactive textile (EAT) has the potential to apply pressure stimuli to the skin, e.g. in the form of a squeeze on the arm. To present a perceivable haptic sensation we need to know the perception threshold for such stimuli. We designed a set-up based on motorized ribbons around the arm with five different widths (range 3 - 49 mm) for psychophysical studies. We investigated the perception threshold of force pressure and ribbon reduction in two studies, using two methods (PSI and 1up/3down staircase), comparing sex, the left and right arm, the lower and upper arm, and stimulated surface area with a total of 57 participants. We found that larger stimulation surfaces require less pressure to reach the perception threshold (0.151 N per cm&lt;inline-formula&gt;&lt;tex-math notation="LaTeX"&gt;$^{2}$&lt;/tex-math&gt;&lt;/inline-formula&gt; for 3 mm width, 0.00972 N per cm&lt;inline-formula&gt;&lt;tex-math notation="LaTeX"&gt;$^{2}$&lt;/tex-math&gt;&lt;/inline-formula&gt; for 49 mm width on the lower arm). This indicates a spatial summation effect for these pressure stimuli. We did not find significant differences in perception threshold for the left and right arm and, the upper and lower arm. Between male and female participants we found significant differences for two conditions (10 mm and 25 mm) in Experiment 1, but we could not reproduce this in Experiment 2.</p

Characteristics of flight simulator visual systems

The physical parameters of the flight simulator visual system that characterize the system and determine its fidelity are identified and defined. The characteristics of visual simulation systems are discussed in terms of the basic categories of spatial, energy, and temporal properties corresponding to the three fundamental quantities of length, mass, and time. Each of these parameters are further addressed in relation to its effect, its appropriate units or descriptors, methods of measurement, and its use or importance to image quality

The scale of sense : spatial extent and multimodal urban design

This paper is derived from the work of the UK AHRC/EPSRC 'Designing for the 21st Century' research project Multimodal Representation of Urban Space. This research group seeks to establish a new form of notation for urban design which pays attention to our entire sensory experience of place. This paper addresses one of the most important aspects of this endeavour: scale. Scale is of course a familiar abstraction to all architects and urban designers, allowing for representations tailored to different levels of detail and allowing drawings to be translated into build structures. Scale is also a factor in human experience: the spatial extent of each of our senses is different. Many forms of architectonic representation are founded upon the extension of the visual modality, and designs are accordingly tuned towards this sense. We can all speak from our own experience, however, that urban environments are a feast for all the senses. The visceral quality of walking down a wide tree-lined boulevard differs greatly from the subterranean crowds of the subway, or the meandering pause invited by the city square. Similarly, our experience of hearing and listening is more than just a passive observation by virtue of our own power of voice and the feedback created by our percussive movements across a surface or through a medium. Taste and smell are also excited by the urban environment, the social importance of food preparation and the associations between smell and public health are issues of sensory experience. The tactile experience of space, felt with the entire body as well as our more sensitive hands, allowing for direct manipulation and interactions as well as sensations of mass, heat, proximity and texture. Our project team shall present a series of tools for designers which explore the variety of sensory modalities and their associated scales. This suite of notations and analytical frameworks turn our attention to the sensory experience of places, and offers a method and pattern book for more holistic multi-sensory and multi-modal urban design

Haptic Edge Detection Through Shear

Most tactile sensors are based on the assumption that touch depends on measuring pressure. However, the pressure distribution at the surface of a tactile sensor cannot be acquired directly and must be inferred from the deformation field induced by the touched object in the sensor medium. Currently, there is no consensus as to which components of strain are most informative for tactile sensing. Here, we propose that shape-related tactile information is more suitably recovered from shear strain than normal strain. Based on a contact mechanics analysis, we demonstrate that the elastic behavior of a haptic probe provides a robust edge detection mechanism when shear strain is sensed. We used a jamming-based robot gripper as a tactile sensor to empirically validate that shear strain processing gives accurate edge information that is invariant to changes in pressure, as predicted by the contact mechanics study. This result has implications for the design of effective tactile sensors as well as for the understanding of the early somatosensory processing in mammals

From pixels to percepts: Highly robust edge perception and contour following using deep learning and an optical biomimetic tactile sensor

Deep learning has the potential to have the impact on robot touch that it has had on robot vision. Optical tactile sensors act as a bridge between the subjects by allowing techniques from vision to be applied to touch. In this paper, we apply deep learning to an optical biomimetic tactile sensor, the TacTip, which images an array of papillae (pins) inside its sensing surface analogous to structures within human skin. Our main result is that the application of a deep CNN can give reliable edge perception and thus a robust policy for planning contact points to move around object contours. Robustness is demonstrated over several irregular and compliant objects with both tapping and continuous sliding, using a model trained only by tapping onto a disk. These results relied on using techniques to encourage generalization to tasks beyond which the model was trained. We expect this is a generic problem in practical applications of tactile sensing that deep learning will solve. A video demonstrating the approach can be found at https://www.youtube.com/watch?v=QHrGsG9AHtsComment: Accepted in RAL and ICRA 2019. N. Lepora and J. Lloyd contributed equally to this wor