294 research outputs found
An investigation of the suitability of Artificial Neural Networks for the prediction of core and local skin temperatures when trained with a large and gender-balanced database
Neural networks have been proven to successfully predict the results of complex non-linear problems in a variety of research fields, including medical research. Yet there is paucity of models utilising intelligent systems in the field of thermoregulation. They are under-utilized for predicting seemingly random physiological responses and in particular never used to predict local skin temperatures; or core temperature with a large dataset. In fact, most predictive models in this field (non-artificial intelligence based) focused on predicting body temperature and average skin temperature using relatively small gender-unbalanced databases or data from thermal dummies due to a lack of larger datasets.
This paper aimed to address these limitations by applying Artificial Intelligence to create predictive models of core body temperature and local skin temperature (specifically at forehead, chest, upper arms, abdomen, knees and calves) while using a large and gender-balanced experimental database collected in office-type situations.
A range of Neural Networks were developed for each local temperature, with topologies of 1â2 hidden layers and up to 20 neurons per layer, using Bayesian and the Levemberg-Marquardt back-propagation algorithms, and using various sets of input parameters (2520 NNs for each of the local skin temperatures and 1760 for the core temperature, i.e. a total of 19400 NNs). All topologies and configurations were assessed and the most suited recommended. The recommended Neural Networks trained well, with no sign of over-fitting, and with good performance when predicting unseen data. The recommended Neural Network for each case was compared with previously reported multi-linear models. Core temperature was avoided as a parameter for local skin temperatures as it is impractical for non-contact monitoring systems and does not significantly improve the precision despite it is the most stable parameter. The recommended NNs substantially improve the predictions in comparison to previous approaches. NN for core temperature has an R-value of 0.87 (81% increase), and a precision of ±0.46 °C for an 80% CI which is acceptable for non-clinical applications. NNs for local skin temperatures had R-values of 0.85-0.93 for forehead, chest, abdomen, calves, knees and hands, last two being the strongest (increase of 72% for abdomen, 63% for chest, and 32% for calves and forehead). The precision was best for forehead, chest and calves, with about ±1.2 °C, which is similar to the precision of existent average skin temperature models even though the average value is more stable
Non-invasive and wearable early fever detection system for young children
Fever in young children is taken seriously by healthcare professionals as it indicates an
underlying infection which can be life-threatening. Core body temperature can be accurately
measured using traditional techniques, but these are not suitable for non-invasive monitoring
during normal life. This study investigates the possibility of fever monitoring in children
under 2 years of age in a non-clinical setting based on various local skin temperatures.
Various system designs are presented, i.e. single vs multi-sensor systems, and a set of sensors
either localized or distributed across the body. The probability of positive fever identification
on feverish children ranges from ~40% to 77% using 1 and 5 sensors respectively, while the
detected false positives are a 10%. We conclude that a continuous and non-invasive fever
monitoring in children under 2 years is possible by the propose method, providing a suitable
solution for early fever detection and alert
360° peer assessment: improving reliability and engagement
A new more rigorous method for peer-assessment was designed and trialled, aiming to improve the studentâs learning experience at UCL and IOE. The â360 degree peer assessmentâ process involves peers firstly marking and giving feedback to pieces of work and secondly being assessed by the recipients of the feedback on the quality of their marking. The peer marking is anonymous. Tutors monitor the process, but only need to intervene and moderate marks if the recipient disputes the mark and feedback, or if there is disparity of marks for one given piece of work. This approach was trialled with two undergraduate Biomedical engineering modules over four assignments and with one postgraduate education module. The benefits we found for this method include formalising the process for dealing with disputes in peer assessment and improving reliability. Undergraduate students also reported dedicating more time to peer assessment, they learnt more about the assessment process and were motivated to read feedback. The postgraduate students were motivated to undertake peer assessment but remained concerned about reliability and they did not appreciate that teacher moderation would occur when needed. The system is still under development. We aim to develop this methodology and use it increasingly in other modules and disciplines, explore for which types of coursework this approach is most suitable, and assess impact on student and staff workload. The authors want to thank to the IOE/UCL Strategic Partnership Teaching and Learning Fund and the Medical Physics and Biomedical Engineering Department UCL who partially funded this project
External-facing assessments: Balancing the needs of students, external partner organisations and the public
Students producing work directed at an external audience - whether a formal assessment, a âshowcase portfolioâ, or a selection of work curated by students outside the curriculum - is emerging as a critical field of enquiry and practice. Drawing on three case studies this roundtable examines the challenges and opportunities as they embed external-facing assessments in programmes of study. After a brief introduction to the institutional context of UCLâs initiatives relating to the Connected Curriculum Collab projects, we will present three different examples: co-produced public facing assessments (Thomas Kador), peer assessments after group work (Pilar Garcia Souto) and the use of portfolios (Nicole Brown). In the subsequent discussion we aim to explore the opportunities for building capacity to establish partnerships between students, external partner organisations and the public. We also discuss the role that educational professionals and colleagues might have in mediating between the institution, its students, staff, and other stakeholders
Moderated peer assessment of individual contribution to group work
UCL Engineering trains students to use engineering knowledge within extended group practical activities to prepare them for their careers after graduation. However, despite the substantial educational benefits of getting students to work in teams, providing individual assessment can be challenging. Students frequently express dissatisfaction if all members of a team are given the same mark regardless of the individual effort. Here, we aim to promote student engagement and improve student experience during group work by giving each student an individual mark. The individual mark results from multiplying the overall âgroup markâ by a personal contribution factor. This personal contribution is assessed directly by peers, who are aware of each team memberâs contribution, encouraging self-reflection, and moderated by tutors when necessary. This practice has been well received by students in other universities. We are working with a student committee to identify and evaluate various methods and e-learning systems that would aid us to run this practice efficiently even for large numbers of students. This includes rules to flag cases requiring moderation. This project, partially funded by ELDG 2015, fits with our aim of increasing studentsâ satisfaction and engagement with assessment. We have combined it with our â360 degrees peer assessment methodâ, which we presented at last yearâs conference, to provide a reliable and individual peer assessment of group work. We provide a novel approach to group assessment which encourages self-reflection and is intended to improve the learning experience and student satisfaction during group work, in line with UCL 2034
Characterization of bespoke force sensors for tailored applications
Bespoke force sensors made with active polymer
composites are inexpensive, thin and flexible, hence popular in
wearable electronics, however their wider application is limited
due to the lack of literature studying their voltage response related
errors. We present the voltage response characterization of
bespoke force sensors made with an active polymer composite,
silver coated fabric, stainless steel thread and silver epoxy.
Characterization of the effects of static and dynamic loading was
completed with a mechanical testing machine. Static tests
consisted of loading and unloading at 0.01, 0.1, 0.5 and 1 N/s, and
drift tests for 120 minutes up to 10 N every 1 N. Dynamic tests
consisted of a sinusoidal load of 5 N ± 1 N applied at 0.05, 0.1 and
0.5 Hz for 60 minutes. The force-voltage relationships were
modelled using an exponential function. Maximum mean drift
error was observed when applying different static loads for 120
minutes each. Drift error is minimal at 5 s (<1%)and at 60 (< 5%)
minutes with loads under 1 N. Maximum hysteresis of 18% was
observed at a 1 N/s loading rate. The maximum drift error after
one hour of dynamic loading was observed at 0.5 Hz and is
minimal (-0.00004%). The cost of fabricating these sensors is very
low compared with commercially available options. These sensors
can be fabricated in any shape and size with the added advantage
of being able to set the location of the electronic connections as
desired
Stress shielding and bone resorption of press-fit polyether-ether-ketone (PEEK) hip prosthesis: a sawbone model study
Stress shielding secondary to bone resorption is one of the main causes of aseptic loosening, which limits the lifespan of the hip prostheses and increases the rates of revision surgery. This study proposes a low stiffness polyether-ether-ketone (PEEK) hip prostheses, produced by fused deposition modelling to minimize the stress difference after the hip replacement. The stress shielding effect and the potential bone resorption of the PEEK implant was investigated through both experimental tests and FE simulation. A generic Ti6Al4V implant was incorporated in this study to allow fair comparison as control group. Attributed to the low stiffness, the proposed PEEK implant showed a more natural stress distribution, less stress shielding (by 104%), and loss in bone mass (by 72%) compared with the Ti6Al4V implant. The stiffness of the Ti6Al4V and the PEEK implant were measured through compression tests to be 2.76 kN/mm and 0.276 kN/mm. The factor of safety for the PEEK implant in both static and dynamic loading scenarios were obtained through simulation. Most of the regions in the PEEK implant were tested to be safe (FoS larger than 1) in terms of representing daily activities (2300 N), while the medial neck and distal restriction point of the implant attracts large von Mises stress 82 MPa and 76 MPa, respectively, and, thus, may possibly fail during intensive activities by yield and fatigue. Overall, considering the reduction in stress shielding and bone resorption in cortical bone, PEEK could be a promising material for the patient-specific femoral implants
Chemical abundance gradients from open clusters in the Milky Way disk: results from the APOGEE survey
Metallicity gradients provide strong constraints for understanding the
chemical evolution of the Galaxy. We report on radial abundance gradients of
Fe, Ni, Ca, Si, and Mg obtained from a sample of 304 red-giant members of 29
disk open clusters, mostly concentrated at galactocentric distances between ~8
- 15 kpc, but including two open clusters in the outer disk. The observations
are from the APOGEE survey. The chemical abundances were derived automatically
by the ASPCAP pipeline and these are part of the SDSS III Data Release 12. The
gradients, obtained from least squares fits to the data, are relatively flat,
with slopes ranging from -0.026 to -0.033 dex/kpc for the alpha-elements [O/H],
[Ca/H], [Si/H] and [Mg/H] and -0.035 dex/kpc and -0.040 dex/kpc for [Fe/H] and
[Ni/H], respectively. Our results are not at odds with the possibility that
metallicity ([Fe/H]) gradients are steeper in the inner disk (R_GC ~7 - 12 kpc)
and flatter towards the outer disk. The open cluster sample studied spans a
significant range in age. When breaking the sample into age bins, there is some
indication that the younger open cluster population in our sample (log age <
8.7) has a flatter metallicity gradient when compared with the gradients
obtained from older open clusters.Comment: 4 pages, 3 figures, To appear in Astronomische Nachrichten, special
issue "Reconstruction the Milky Way's History: Spectroscopic surveys,
Asteroseismology and Chemo-dynamical models", Guest Editors C. Chiappini, J.
Montalb\'an, and M. Steffen, AN 2016 (in press)
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