922017 research outputs found
Sort by
Optimised cell growth and poly(3-hydroxybutyrate) synthesis from saponified spent coffee grounds oil
No full textSpent coffee grounds (SCG) oil is an ideal substrate for the biosynthesis of polyhydroxyalkanoates (PHAs) by Cupriavidus necator. The immiscibility of lipids with water limits their bioavailability, but this can be resolved by saponifying the oil with potassium hydroxide to form water-soluble fatty acid potassium salts and glycerol. Total saponification was achieved with 0.5 mol/L of KOH at 50 °C for 90 min. The relationship between the initial carbon substrate concentration (C0) and the specific growth rate (µ) of C. necator DSM 545 was evaluated in shake flask cultivations; crude and saponified SCG oils were supplied at matching initial carbon concentrations (C0 = 2.9-23.0 g/L). The Han-Levenspiel model provided the closest fit to the experimental data and accurately described complete growth inhibition at 32.9 g/L (C0 = 19.1 g/L) saponified SCG oil. Peak µ-values of 0.139 h−1 and 0.145 h−1 were obtained with 11.99 g/L crude and 17.40 g/L saponified SCG oil, respectively. Further improvement to biomass production was achieved by mixing the crude and saponified substrates together in a carbon ratio of 75:25% (w/w), respectively. In bioreactors, C. necator initially grew faster on the mixed substrates (µ = 0.35 h−1) than on the crude SCG oil (µ = 0.23 h−1). After harvesting, cells grown on crude SCG oil obtained a total biomass concentration of 7.8 g/L and contained 77.8 % (w/w) PHA. Whereas cells grown on the mixed substrates produced 8.5 g/L of total biomass and accumulated 84.4 % (w/w) of PHA
A scoping review of the literature on prosodic elements related to emotional speech in human-robot interaction
No full textBackground: Sentiment expression and detection are crucial for effective and empathetic human-robot interaction. Previous work in this field often focuses on non-verbal emotion expression, such as facial expressions and gestures. Less is known about which specific prosodic speech elements are required in human-robot interaction. Our research question was: what prosodic elements are related to emotional speech in human-computer/robot interaction?Methods: The scoping review was conducted in alignment with the Arksey and O’Malley methods. Literature was identified from the SCOPUS, IEEE Xplore, ACM Digital Library and PsycINFO databases in May 2021. After screening and de-duplication, data were extracted into an Excel coding sheet and summarised.Results: Thirteen papers, published from 2012 to 2020 were included in the review. The most commonly used prosodic elements were tone/pitch (n=8), loudness/volume (n=6) speech speed (n=4) and pauses (n=3). Non-linguistic vocalisations (n=1) were less frequently used. The prosodic elements were generally effective in helping to convey or detect emotion, but were less effective for negative sentiment (e.g., anger, fear, frustration, sadness and disgust).Discussion: Future research should explore the effectiveness of commonly used prosodic elements (tone, loudness, speed and pauses) in emotional speech, using larger sample sizes and real-life interaction scenarios. The success of prosody in conveying negative sentiment to humans may be improved with additional non-verbal cues (e.g., coloured light or motion). More research is needed to determine how these may be combined with prosody and which combination is most effective in human-robot affective interaction.Keywords: affective computing; speech; HRI; robotics; social robots; sentiment<br/
Some Effects of Surface Finish and LWR Environment on Environmentally-assisted Crack Initiation in Alloy 182
No full textWithin the European Commission funded project MEACTOS, environmentally-assisted crack (EAC) initiation of Alloy 182 was addressed by performing constant extension rate tensile (CERT) and constant load (CL) testing of flat, tapered tensile specimens in both boiling water reactor (BWR) normal water chemistry (NWC) and pressurized water reactor (PWR) primary water environment. Four surface finishes were investigated, namely: ground which serves as reference (RS), industrial face-milled (STI), advanced-machined (SAM) and two shot peened conditions (SP, initial and later). After testing the critical stress for initiating a crack was derived by locating the critical section (the border between areas showing and not showing surface cracking after testing) and calculating the associated local stress. In a first analysis of the CERT results, the critical stress was plotted against the nominal strain rate (cross-head displacement rate divided by the length of the tapered gauge section) and an exponential curve was fitted to it; yielding a characteristic critical stress (extrapolation to zero nominal strain rate) and a characteristic nominal strain rate (rendering the nominal strain rate dimensionless under the exponent). In a second analysis of the CERT results, an initiation model, which is strain rate and stress level dependent, was fitted to obtain a usage towards EAC initiation of 1 in the experimentally-determined critical cross section. CL testing was performed under the same and accelerated test conditions, achieved by increasing temperature and changing test environment. The overall conclusion is that (1) EAC initiation performance is better in the BWR/NWC than in the PWR environment, (2) effects of surface finish are more clearly visible in the PWR environment, (3) EAC initiation performance is better for SAM than for RS or STI which are similar and in turn better than the original SP. A “higher quality” SP surface showed an improvement in EAC initiation performance and this correlated well with the lower surface hardness measured for the latter meaning that hardness could be used as a measure for the quality of surface treatments in respect of EAC initiation
Establishing the reliability and the validity of the Arabic translated versions of the Effort Assessment Scale and the Fatigue Assessment Scale
No full textObjective: The aim was to establish the reliability and the validity of Arabic translated versions of the Fatigue Assessment Scale (FAS) and the Effort Assessment Scale (EAS). Design: The FAS and the EAS were translated from the original English following a recommended six-step approach for translating hearing-related questionnaires for different languages. The reliability of the scales was investigated using Cronbach’s alpha, item-total correlation, and inter-item correlation. Construct validity was investigated using factor analysis and the hypothesis testing method.Study sample: The translated scales were completed by 146 participants from Jordan and Saudi Arabia (age range 19-86 years old, 39% male). Participants’ hearing level ranged from normal to profound.Results: Item 3 in the translated FAS was removed to improve the scale’s construct validity. The translated version of the EAS was found to be as reliable and valid as the original EAS.Conclusion: The availability of standardized versions of the FAS and the EAS provides a quick and easy method for improving hearing rehabilitation in Arabic-speaking countries where audiology services can often be costly and not necessarily accessible to all individuals
A Proof System for Cyber-physical Systems with Shared-Variable Concurrency
No full textCyber-physical system (CPS) is about the interplay of discrete behaviors and continuous behaviors. The combination of the physical and the cyber may cause hardship for the modeling and verication of CPS. Hence, a language based on shared variables was proposed to realize the interaction in CPS. In this paper, we formulate a proof system for this language. To handle the parallel composition with shared variables, we extend classical Hoare triples and bring the trace model into our proof system. The introduction of the trace may complicate ourspecication slightly, but it can realize a compositional proof when the program is executing. Meanwhile, this introduction can set up a bridge between our proof system and denotational semantics. Throughout this paper, we also present some examples to illustrate the usage of our proof system intuitively.Keywords: Cyber-physical System (CPS) · Shared Variables · Trace Model · Hoare Logic
Pre-sleep alpha brainwave entrainment by audio or visual stimulation for people with chronic pain and sleep disturbance; a feasibility study
No full textVirtual wards: A rapid evidence synthesis and implications for the care of older people
No full textBackgroundVirtual wards are being rapidly developed within the National Health Service in the UK, and frailty is one of the first clinical pathways. Virtual wards for older people and existing hospital at home services are closely related.MethodsIn March 2022 we searched Medline, CINAHL, the Cochrane Database of Systematic Reviews and medRxiv for evidence syntheses which addressed clinical-effectiveness, cost-effectiveness, barriers and facilitators, or staff, patient or carer experience for virtual wards, hospital at home or remote monitoring alternatives to inpatient care.ResultsWe included 28 evidence syntheses mostly relating to hospital at home. There is low to moderate certainty evidence that clinical outcomes including mortality (example pooled RR 0.77, 95% CI 0.60 to 0.99) were probably equivalent or better for hospital at home. Subsequent residential care admissions are probably reduced (example pooled RR 0.35, 95% CI 0.22 to 0.57). Cost-effectiveness evidence demonstrated methodological issues which mean the results are uncertain. Evidence is lacking on cost implications for patients and carers. Barriers and facilitators operate at multiple levels (organisational, clinical and patient). Patient satisfaction may be improved by hospital at home relative to inpatient care. Evidence for carer experience is limited.ConclusionsThere is substantial evidence for the clinical effectiveness of hospital at home but less evidence for virtual wards. Guidance for virtual wards is lacking on key aspects including team characteristics, outcome selection and data protection. We recommend that research and evaluation is integrated into development of virtual ward models. The issue of carer strain is particularly relevant
Combining sparse approximate factorizations with mixed precision iterative refinement
No full textThe standard LU factorization-based solution process for linear systems can be enhanced in speed or accuracy by employing mixed precision iterative refinement. Most recent work has focused on dense systems. We investigate the potential of mixed precision iterative refinement to enhance methods for sparse systems based on approximate sparse factorizations. In doing so we first develop a new error analysis for LU- and GMRES-based iterative refinement under a general model of LU factorization that accounts for the approximation methods typically used by modern sparse solvers, such as low-rank approximations or relaxed pivoting strategies. We then provide a detailed performance analysis of both the execution time and memory consumption of different algorithms, based on a selected set of iterative refinement variants and approximate sparse factorizations. Our performance study uses the multifrontal solver MUMPS, which can exploit block low-rank (BLR) factorization and static pivoting. We evaluate the performance of the algorithms on large, sparse problems coming from a variety of real-life and industrial applications showing that the proposed approach can lead to considerable reductions of both the time and memory consumption
A Benchmark for Multi-Class Object Counting and Size Estimation Using Deep Convolutional Neural Networks
No full textAutomatic object counting and object size estimation in digital images can be very useful in many real-world applications such as surveillance, smart farming, intelligent traffic systems, etc. However, most existing research mainly focus on scenarios where only one type of object is considered due to the lack of proper datasets. Furthermore, they use the traditional detection algorithms for size estimation and can only do segmenting tasks but cannot identify different types of objects and return corresponding individual size information. To fill these gaps, we create a synthetic dataset and propose a benchmark for multi-class object counting and size estimation (MOCSE) within a unified framework. We create the dataset MOCSE13 by using Unity to generate synthetic images for 13 different objects (fruits and vegetables). Besides, we propose a deep architecture approach for multi-class object counting and object size estimation. Our proposed models with different backbones are evaluated on the synthetic dataset. The experimental results provide a benchmark for multi-class object counting and size estimation and the synthetic dataset can be served as a proper testbed for future studies