Towards Stroke Patients' Upper-limb Automatic Motor Assessment Using Smartwatches

Assessing the physical condition in rehabilitation scenarios is a challenging problem, since it involves Human Activity Recognition (HAR) and kinematic analysis methods. In addition, the difficulties increase in unconstrained rehabilitation scenarios, which are much closer to the real use cases. In particular, our aim is to design an upper-limb assessment pipeline for stroke patients using smartwatches. We focus on the HAR task, as it is the first part of the assessing pipeline. Our main target is to automatically detect and recognize four key movements inspired by the Fugl-Meyer assessment scale, which are performed in both constrained and unconstrained scenarios. In addition to the application protocol and dataset, we propose two detection and classification baseline methods. We believe that the proposed framework, dataset and baseline results will serve to foster this research field

Transcription of manuscrits with image processing techniques and gamesourcing

Information inside the historical documents can provide us knowledge about the evolution of the past. In local censuses, there are names that appear the 80% of times. The transcription process could be accelerated doing a massive transcription of frequent names. In this work we propose to use clustering methods and validate them via gamesourcing. The validation is needed because the performance of image processing techniques is still far from satisfactory. Several experiments are performed showing the viability of the massive transcription through clustering methods and the gamesourcing application for validation.La información contenida en los documentos históricos puede ayudarnos a comprender el pasado. En los censos locales, hay nombres que aparecen el 80\% de las veces. El proceso de transcripción puede ser acelerado realizando una transcripción masiva d'estos nombres frecuentes. En este trabajo proponemos utilizar métodos de clustering y validarlos con gamesourcing. La validación es necesaria ya que el rendimiento de estas técnicas aun no llegan a ser satisfactorias. Varias pruebas fueron realizados y todas indican la viabilidad de la transcripción masiva con métodos de clustering y validación mediante gamesourcing.La informació continguda en els documents històrics ens pot ajudar a comprendre el pasat. En censos locals, hi ha noms que apareixen el 80% dels cops. El procés de transcripció es pot accel·lerar fent una transcripció massiva d'aquests noms freqüents. En aquest treball proposem utilitzar mètodes de clustering i validar-los amb gamesourcing. La validació es necessària ja que el rendiment d'aquestes tècniques encara no arriben a ser satisfactories. Varies proves s'han realitzat i totes indiquen la viabilitat de la transcripció massiva amb mètodes de clustering i validació via gamesourcing

Multi-energy source (MES) configuration for bead shape control in wire-based directed energy deposition (w-DED)

A multi-energy source (MES) method featuring a high-power scanning laser (SL) was used to achieve independent control of layer width and height in a wire-based directed energy deposition (w-DED) process. In the MES system, a plasma transferred arc (PTA) was employed to create an initial melt pool and melt the wire, and a SL was used to reshape the melt pool and precisely control the bead width. The distance between the SL and the PTA and different laser scanning strategies were investigated. Images of the melt pool with varying scanning widths were captured. A bead shape control strategy was demonstrated by using the wire feed speed to control layer height and the laser scanning width to control the layer width independent of each other. The advancing speed was adjusted in proportion to the scanning width to keep the same specific process energy of the SL. The experimental results demonstrated that the MES approach provides independent control of layer width and height. Some single-pass walls were built using the MES to show that MES can be used for w-DED additive manufacturing.Engineering and Physical Sciences Research Council (EPSRC): EP/R027218/1

Split anode calorimetry for plasma arc energy density measurement with laser calibration

A split anode calorimeter (SAC) has been developed for the measurement of plasma transferred arc (PTA) energy density. A novel aspect is the use of a laser beam with a well-defined energy profile which was first measured using a commercial laser beam diagnosis system and was used to calibrate the SAC. The SAC temperature data generated profile showed the same profile measured by the laser diagnosis system. This confirmed the accuracy of the SAC method and its suitability for measuring the energy distribution of an electric arc if provided stably. The PTA energy profile was observed to be distorting when crossing over the split anode interface of the SAC. This was corrected by moving the ground wire from the side to the centre of the anode. Detailed analysis of 130A PTA energy density profiles generated from both the current density and the temperature distribution of the arc showed that the current data generated profile is narrower than that of the temperature data generated profile. This indicates that the effective energy distribution is wider than that of the width of the arc column due to other energy transfer processes such as convection and radiation. The energy absorption distribution matched well to a Gaussian distribution model with a radius of 7 mm. The arc energy absorption rate of the copper plate was measured and found to be about 56%.Engineering and Physical Sciences Research Council (EPSRC): EP/R027218/

A three-dimensional wire-feeding model for heat and metal transfer, fluid flow, and bead shape in wire plasma arc additive manufacturing

A three-dimensional wire-feeding model has been developed to study the transient coupling behaviour of heat and metal transfer, fluid flow, and solidified bead shape in wire plasma arc additive manufacturing (WPAAM). A novel surface heat source model considering the arc energy shading effect is proposed and adopted. An improved momentum source of the arc force considering the arc pressure shading effect is also developed and used. This model has been used to study the metal transfer dynamics, flow patterns, and bead shape of the WPAAM process with a wire-feeding speed (WFS) of 1–5 m/min. The simulated results agreed reasonably with the experimental data. As the WFS increased from 1 to 5 m/min, three different metal transfer modes were observed, which changed from globular droplet mode to droplet-liquid bridge mode and solid-liquid bridge mode. Detailed metal transfer information was analysed, including metal transfer position, shape, average temperature, and main driving force. The effects of the arc shading and metal transfer on the melt pool dynamics and bead shape were simulated and discussed. A periodic flow pattern of the melt pool produced by the metal transfer impact causes ripples or even humping defects. As the WFS increased, the melt pool depression gradually disappeared due to the arc pressure shading effect. When the WFS increased to 5 m/min, a temperature drop of about 140 K in the central melt pool, caused by the arc energy shading effect and cold metal transfer, weakened the lateral flow significantly, which explained the decrease of bead width at a large WFS. The results demonstrate that the developed wire-feeding model and findings could be used as a theoretical tool and basis to better understand the underlying physical mechanisms and achieve bead shape control in the WAAM process

Efficient reduced-order thermal modelling of scanning laser melting for additive manufacturing

Additive manufacturing (AM) with a scanning laser (SL) to independently control melt pool shape has the potential to achieve part building with high geometric accuracy and complexity. An innovative dynamic convection boundary (DCB) method is proposed to develop a reduced-order finite element (FE) model to accelerate the thermal analysis of a SL process for AM. The DCB method approximates the thermal conduction of the adjacent material around the bead region by using a convection boundary condition that can be dynamically adjusted during the numerical solution. Thereby, a smaller problem domain and fewer elements are involved in the reduced-order FE modelling. A non-oscillating equivalent bar-shaped heat source was also introduced as a simplified substitution for a high oscillation frequency SL heat source. The DCB-based reduced-order thermal model achieved over 99% accuracy compared to the full-scale model but reduced the element amount by 73% and the computational time by 58%. The use of the bar-shaped equivalent heat source can further enhance computational efficiency without compromising the prediction accuracy of a high oscillation frequency SL process. The DCB-based reduced-order thermal modelling method and equivalent heat source could be adopted to boost extensive parametric analysis and optimisation for novel AM processes. Study on large structures AM could also be facilitated by simplifying the computation at critical regions. This study can also enable efficient thermal analyses of different manufacturing processes, such as welding, cladding, and marking.Engineering and Physical Sciences Research Council (EPSRC): EP/R027218/

The impact of subclinical hypothyroidism on growth and development in infants and young children aged 0 to 5 years

Introduction: The objective was to investigate the growth and development of infants and young children with mild subclinical hypothyroidism aged 0 to 5 years, especially those aged 0 to 2 years. Material and methods: The study was a retrospective analysis of the birth status, physical growth, and neuromotor development of patients aged 0 to 5 years, who were diagnosed with subclinical hypothyroidism during newborn screening (NBS) in Zhongshan between 2016 and 2019. Based on preliminary results, we compared 3 groups: with thyroid-stimulating factor (TSH) value of 5–10 mIU/L (442 cases), TSH value of 10–20 mIU/L (208 cases), and TSH above 20 mIU/L (77 cases). Patients with TSH value above 5 mIU/L were called back for repeat testing and were divided into 4 groups as follows: mild subclinical hypothyroidism group 1 with a TSH value of 5–10 mIU/L in both initial screening and repeat testing; mild subclinical hypothyroidism group 2 with TSH value above 10 mIU/L in initial screening; and TSH value of 5–10 mIU/L in repeat testing; the severe subclinical hypothyroidism group with TSH value of 10–20 mIU/L in both the initial screening and repeat testing and the congenital hypothyroidism group. Results: There were no significant differences in the maternal age, type of delivery, gender, length, and weight at birth between the preliminary groups; however, the gestational age at birth was significantly different (F = 5.268, p = 0.005). The z-score for length at birth was lower in the congenital hypothyroidism group compared to the other 3 groups but showed no difference at 6 months of age. The z-score for length in mild subclinical hypothyroidism group 2 was lower compared to the other 3 groups but showed no difference at 2–5 years of age. At 2 years of age there was no significant difference in the developmental quotient (DQ) of the Gesell Developmental Scale between the groups. Conclusion: The gestational age at birth affected the neonatal TSH level. Intrauterine growth in infants with congenital hypothyroidism was retarded compared to that of infants with subclinical hypothyroidism. Neonates with a TSH value of 10–20 mIU/L in the initial screening and a TSH value of 5–10 mIU/L in the repeat testing showed developmental delay at 18 months but caught up at age 2 years. There was no difference in neuromotor development between the groups. Levothyroxine in patients with mild subclinical hypothyroidism is not required, but we recommend that the growth and development of such infants and young children continues to be monitored

Thermal fluid dynamics of the effect of filler wire on deposition rate and bead formation intending plasma arc-based DED

The influence of filler wire configuration, such as size and geometry, on the deposition rate (DR) and bead formation, has been studied in wire arc-based directed energy deposition (WADED), but the fundamental physics underlying its effect on wire melting and melt pool dynamics remains unclear. In this paper, a series of plasma arc-based DED (plasma-DED) experiments were conducted to investigate the impact of five different filler wire configurations on DR and bead dimensions. The coupling behaviours of wire melting, metal transfer and melt pool dynamics under the five filler wire configurations were also simulated numerically using the authors' recently developed wire-feeding model. The calculated wire melting and bead cross-sections are consistent with the experimental images and measurements. The results demonstrate that the filler wire significantly affects the highest DR by altering wire melting and metal transfer behaviours through changes in arc energy absorption. The filler wire with a rhombus geometry which is closer to a Gaussian-like arc distribution than the flat wire was shown to get higher DR and more stable metal transfer. Furthermore, different filler wire configurations lead to distinct melt pool behaviours, including temperature distribution and flow velocity, due to various metal transfer behaviours and arc shading effects. This study sheds light on the fundamental physics underlying the impact of filler wire on wire melting and bead formation for the first time. The methods and findings can guide improving DR and controlling bead shape in the plasma-DED process