Real-time 3D shape sensing and reconstruction scheme based upon fibre optic bragg gratings

An array of FBG curvature sensors are wavelength-interrogated and the recovered data combined with a three-dimensional algorithm to reconstruct in real time the enveloped object with a 1% to 9% volumetric error. © 2012 OSA.

Free secretory component from cystic fibrosis sputa displays the cystic fibrosis glycosylation phenotype

Secretory IgA contributes to humoral defense mechanisms against pathogens targeting mucosal surfaces, and secretory component (SC) fulfills multiple roles in this defense. The aims of this study were to quantify total SC and to analyze the form of free SC in sputa from normal subjects, subjects with asthma, and subjects with cystic fibrosis (CF). Significantly higher levels of SC were detected in CF compared with both other groups. Gel filtration chromatography revealed that SC in CF was relatively degraded. Free SC normally binds interleukin (IL)-8 and inhibits its function. However, in CF sputa, IL-8 binding to intact SC was reduced. Analysis of the total carbohydrate content of free SC signified overglycosylation in CF compared with normal subjects and subjects with asthma. Monosaccharide composition analysis of free SC from CF subjects revealed overfucosylation and undersialylation, in agreement with the reported CF glycosylation phenotype. SC binding to IL-8 did not interfere with the binding of IL-8 to heparin, indicating distinct binding sites on IL-8 for negative regulation of function by SC and heparin. We suggest that defective structure and function of SC contribute to the characteristic sustained inflammatory response in the CF airways.

Effects of crack length and shape on the fracture toughness of a high strength steel 300m

The results of fracture toughness tests on a high strength steel 300m are presented. These results show (i) that in the presence of through-thickness cracks the toughness remains constant down to (a/W)-ratios as low as 0.01 and failure loads up to 0.85σy, and (ii) that the material is more resistant to crack growth when the cracks are semi-elliptical in shape, giving a toughness value which is almost 25 per cent higher than the through-thickness one. Three independent stress analyses are used to obtain stress intensity values for the semi-elliptical cracks and additional confirmation of the increase in toughness comes from stretch zone measurements.

Monitoring static shape memory polymers using a fiber Bragg grating as a vector-bending sensor

We propose and demonstrate a technique for monitoring the recovery deformation of the shape-memory polymers (SMP) using a surface-attached fiber Bragg grating (FBG) as a vector-bending sensor. The proposed sensing scheme could monitor the pure bending deformation for the SMP sample. When the SMP sample undergoes concave or convex bending, the resonance wavelength of the FBG will have red-shift or blue-shift according to the tensile or compressive stress gradient along the FBG. As the results show, the bending sensitivity is around 4.07  nm/cm−1. The experimental results clearly indicate that the deformation of such an SMP sample can be effectively monitored by the attached FBG not just for the bending curvature but also the bending direction.

Monitoring of deployment process of shape memory polymers for morphing structures with embedded fibre Bragg grating sensors

This article demonstrates the use of embedded fibre Bragg gratings as vector bending sensor to monitor two-dimensional shape deformation of a shape memory polymer plate. The shape memory polymer plate was made by using thermal-responsive epoxy-based shape memory polymer materials, and the two fibre Bragg grating sensors were orthogonally embedded, one on the top and the other on the bottom layer of the plate, in order to measure the strain distribution in both longitudinal and transverse directions separately and also with temperature reference. When the shape memory polymer plate was bent at different angles, the Bragg wavelengths of the embedded fibre Bragg gratings showed a red-shift of 50 pm/°caused by the bent-induced tensile strain on the plate surface. The finite element method was used to analyse the stress distribution for the whole shape recovery process. The strain transfer rate between the shape memory polymer and optical fibre was also calculated from the finite element method and determined by experimental results, which was around 0.25. During the experiment, the embedded fibre Bragg gratings showed very high temperature sensitivity due to the high thermal expansion coefficient of the shape memory polymer, which was around 108.24 pm/°C below the glass transition temperature (Tg) and 47.29 pm/°C above Tg. Therefore, the orthogonal arrangement of the two fibre Bragg grating sensors could provide a temperature compensation function, as one of the fibre Bragg gratings only measures the temperature while the other is subjected to the directional deformation. © The Author(s) 2013.

Gratings in novel fibre geometry for applications in shape sensing

A long period grating (LPG) fabricated in progressive three-layered (PTL) fibre is described. The grating with a period of 391µm, had dual attenuation bands associated with a particular cladding mode. The dual attenuation bands have been experimentally characterised for their spectral sensitivity to bending, which resulted in the highest sensitivity to bending seen for this particular fibre and temperature. The spectral characteristics of the fibre have been modelled giving good agreement to the experimental data as well as showing that the attenuation bands are both associated with the second order HE/EH2,n cladding mode.

Optical chemsensors based on etched fibre Bragg gratings in D-shape and multimode fibres

We present an implementation of high-sensitivity optical chemsensors based on FBGs UV-inscribed in D-shape and multimode fibres and sensitized by HF-etching treatment, demonstrating a capability of detecting chemical concentration changes as small as < 0.5%.

Exploring novel auditory displays for supporting accelerated skills acquisition and enhanced performance in motorsport

This paper explores the design, development and evaluation of a novel real-time auditory display system for accelerated racing driver skills acquisition. The auditory feedback provides concurrent sensory augmentation and performance feedback using a novel target matching design. Real-time, dynamic, tonal audio feedback representing lateral G-force (a proxy for tire slip) is delivered to one ear whilst a target lateral G-force value representing the ‘limit’ of the car, to which the driver aims to drive, is panned to the driver’s other ear; tonal match across both ears signifies that the ‘limit’ has been reached. An evaluation approach was established to measure the efficacy of the audio feedback in terms of performance, workload and drivers’ assessment of self-efficacy. A preliminary human subject study was conducted in a driving simulator environment. Initial results are encouraging, indicating that there is potential for performance gain and driver confidence enhancement based on the audio feedback.

Shape from photographs:a multi-view stereo pipeline

Acquiring 3D shape from images is a classic problem in Computer Vision occupying researchers for at least 20 years. Only recently however have these ideas matured enough to provide highly accurate results. We present a complete algorithm to reconstruct 3D objects from images using the stereo correspondence cue. The technique can be described as a pipeline of four basic building blocks: camera calibration, image segmentation, photo-consistency estimation from images, and surface extraction from photo-consistency. In this Chapter we will put more emphasis on the latter two: namely how to extract geometric information from a set of photographs without explicit camera visibility, and how to combine different geometry estimates in an optimal way. © 2010 Springer-Verlag Berlin Heidelberg.

Book review: Laurel Kamada, Hybrid Identities and Adolescent Girls: Being Half in Japan. Bristol: Multilingual Matters, 2010

Arguably, the catalyst for the best research studies using social analysis of discourse is personal ‘lived’ experience. This is certainly the case for Kamada, who, as a white American woman with a Japanese spouse, had to deal first hand with the racialization of her son. Like many other mixed-ethnic parents, she experienced the shock and disap-pointment of finding her child being racialized as ‘Chinese’ in America through peer group taunts, and constituted as gaijin (a foreigner) in his own homeland of Japan. As a member of an e-list of the (Japan) Bilingualism Special Interest Group (BSIG), Kamada learnt that other parents from the English-speaking foreign community in Japan had similar disturbing stories to tell of their mixed-ethnic children who, upon entering the Japanese school system, were mocked, bullied and marginalized by their peers. She men-tions a pervasive Japanese proverb which warns of diversity or difference getting squashed: ‘The nail that sticks up gets hammered down’. This imperative to conform to Japanese behavioural and discursive norms prompted Kamada’s quest to investigate the impact of ‘otherization’ on the identities of children of mixed parentage. In this fascinat-ing book, she shows that this pressure to conform is balanced by a corresponding cele-bration of ‘hybrid’ or mixed identities. The children in her study are also able to negotiate their identities positively as they come to terms with contradictory discursive notions of ‘Japaneseness’, ‘whiteness’ and ‘halfness/doubleness’.The discursive construction of identity has become a central concern amongst researchers across a wide range of academic disciplines within the humanities and the social sciences, and most existing work either concentrates on a specific identity cate-gory, such as gender, sexuality or national identity, or else offers a broader discussion of how identity is theorized. Kamada’s book is refreshing because it crosses the usual boundaries and offers divergent insights on identity in a number of ways. First, using the term ‘ethno-gendering’, she examines the ways in which six mixed-ethnic girls living in Japan accomplish and manage the relationship between their gender and ethnic ‘differ-ences’ from age 12 to 15. She analyses in close detail how their actions or displays within certain situated interactions might come into conflict with how they are seen or constituted by others. Second, Kamada’s study builds on contemporary writing on the benefits of hybridity where identities are fluid, flexible and indeterminate, and which contest the usual monolithic distinctions of gender, ethnicity, class, etc. Here, Kamada carves out an original space for her findings. While scholars have often investigated changing identities and language practices of young people who have been geographi-cally displaced and are newcomers to the local language, Kamada’s participants were all born and brought up in Japan, were fluent in Japanese and were relatively proficient in English. Third, the author refuses to conceptualize or theorize identity from a single given viewpoint in preference to others, but in postmodernist spirit draws upon multiple perspectives and frameworks of discourse analysis in order to create different forms of knowledge and understandings of her subject. Drawing on this ‘multi-perspectival’ approach, Kamada examines grammatical, lexical, rhetorical and interactional features from six extensive conversations, to show how her participants position their diverse identities in relation to their friends, to the researcher and to the outside world. Kamada’s study is driven by three clear aims. The first is to find out ‘whether there are any tensions and dilemmas in the ways adolescent girls of Japanese and “white” mixed parentage in Japan identify themselves in terms of ethnicity’. In Chapter 4, she shows how the girls indeed felt that they stood out as different and consequently experienced isolation, marginalization and bullying at school – although they were able to make better sense of this as they grew older, repositioning the bullies as pitiable. The second aim is to ask how, if at all, her participants celebrate their ethnicity, and furthermore, what kind of symbolic, linguistic and social capital they were able to claim for themselves on the basis of their hybrid identities. In Chapter 5, Kamada shows how the girls over time were able to constitute themselves as insiders while constituting ‘the Japanese’ as outsiders, and their network of mixed-ethnic friends was a key means to achieve this. In Chapter 6, the author develops this potential celebration of the girls’ mixed ethnicity by investigating the privileges they perceived it afforded them – for example, having the advantage of pos-sessing English proficiency and intercultural ‘savvy’ in a globalized world. Kamada’s third aim is to ask how her participants positioned themselves and performed their hybrid identities on the basis of their constituted appearance: that is, how the girls saw them-selves based on how they looked to others. In Chapter 7, the author shows that, while there are competing discourses at work, the girls are able to take up empowering positions within a discourse of ‘foreigner attractiveness’ or ‘a white-Western female beauty’ discourse, which provides them with a certain cachet among their Japanese peers. Throughout the book, Kamada adopts a highly self-reflexive perspective of her own position as author. For example, she interrogates the fact that she may have changed the lived reality of her six participants during the course of her research study. As the six girls, who were ‘best friends’, lived in different parts of the Morita region of Japan, she had to be proactive in organizing six separate ‘get-togethers’ through the course of her three-year study. She acknowledges that she did not collect ‘naturally occurring data’ but rather co-constructed opportunities for the girls to meet and talk on a regular basis. At these meetings, she encouraged the girls to discuss matters of identity, prompted by open-ended interview questions, by stimulus materials such as photos, articles and pic-tures, and by individual tasks such as drawing self-portraits. By giving her participants a platform in this way, Kamada not only elicited some very rich spoken data but also ‘helped in some way to shape the attitudes and self-images of the girls positively, in ways that might not have developed had these get-togethers not occurred’ (p. 221). While the data she gathers are indeed rich, it may well be asked whether there is a mismatch between the girls’ frank and engaging accounts of personal experience, and the social constructionist academic register in which these are later re-articulated. When Kamada writes, ‘Rina related how within the more narrow range of discourses that she had to draw on in her past, she was disempowered and marginalized’ (p. 118), we know that Rina’s actual words were very different. Would she really recognize, understand and agree with the reported speech of the researcher? This small omission of self-reflexivity apart – an omission which is true of most lin-guistic ethnography conducted today – Kamada has written a unique, engaging and thought-provoking book which offers a model to future discourse analysts investigating hybrid identities. The idea that speakers can draw upon competing discourses or reper-toires to constitute their identities in contrasting, creative and positive ways provides linguistic researchers with a clear orientation by which to analyse the contradictions of identity construction as they occur across time in different discursive contexts