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Towards a resilience assurance model for robotic autonomous systems
Get PDFYesApplications of autonomous systems are becoming increasingly common across the field of engineered systems from cars, drones, manufacturing systems and medical devices, addressing prevailing societal changes, and, increasingly, consumer demand. Autonomous systems are expected to self-manage and self-certify against risks affecting the mission, safety and asset integrity. While significant progress has been achieved in relation to the modelling of safety and safety assurance of autonomous systems, no similar approach is available for resilience that integrates coherently across the cyber and physical parts. This paper presents a comprehensive discussion of resilience in the context of robotic autonomous systems, covering both resilience by design and resilience by reaction, and proposes a conceptual model of a system of learning for resilience assurance in a continuous product development framework. The resilience assurance model is proposed as a composable digital artefact, underpinned by a rigorous model-based resilience analysis at the system design stage, and dynamically monitored and continuously updated at run time in the system operation stage, with machine learning based knowledge extraction and validation
Ppia and ywhaz constitute a stable pair of reference genes during electrical stimulation in mesenchymal stem cells
Get PDFYesMesenchymal stem cells (MSCs) are multipotent adult stem cells with great potential in regenerative medicine. One method for stimulating proliferation and differentiation of MSCs is via electrical stimulation (ES). A valuable approach for evaluating the response of MSCs to ES is to assess changes in gene expression, relative to one or more reference genes. In a survey of 25 publications that used ES on cells, 70% selected GAPDH as the reference gene. We conducted a study to assess the suitability of six potential reference genes on an immortalized human MSC line following direct current ES at seeding densities of 5000 and 10,000 cells/cm2 . We employed three methods to validate the most stable reference genes from qRT-PCR data. Our findings show that GAPDH and ACTB exhibit reduced stability when seeded at 5000 cell/cm2 . In contrast, we found that the most stable genes across both plating densities and stimulation regimes were PPIA and YWHAZ. Thus, in ES gene expression studies in MSCs, we support the use of PPIA and YWHAZ as an optimal reference gene pair, and discourage the use of ACTB and GAPDH at lower seeding densities. However, it is strongly recommended that similar verification studies are carried out based on cell type and different ES conditions
Study on interfacial bond behavior of recycled aggregate concrete filled stainless steel tubes (RAC-FSST)
Get PDFYesIn this work, the interfacial bond performance of recycled aggregate concrete filled stainless steel tube (RAC-FSST) members was investigated through the repeated push-out tests. Three coarse recycled aggregate (CRA) replacements (0, 50% and 100%) and two cross-sectional dimensions were considered in the experimental program. The failure pattern, bond stress-slip response and strain development of stainless steel tube were obtained, and the bond mechanisms under different loading stages were analyzed. Test results showed that the ultimate bond stress increases with the increasing CRA content and decreasing cross-sectional dimensions. Compared with CFST members having carbon steel, RAC-FSST members present lower bond stress. The macro-interlocking effect is obvious in the later loading stage, resulting in a significant increase in the post-peak bond slip curves. Finally, the ultimate bond strength and idealized bond stress-slip models for the RAC-FSST members were suggested on the basis of the test results
Stability and consolidation of sediment tailings incorporating unsaturated soil mechanics
Get PDFYesTailing dams are commonly used to safely store tailings without damaging the environment. Sand tailings (also called Sediment tailings) usually have a high water content and hence undergo consolidation during their placement. As the sediment tailings are usually placed above the ground water level, the degree of saturation and permeability of the sediment tailing is associated with the unsaturated condition due to the presence of negative pore-water pressure or suction. Current practices normally focus on the analyses saturated conditions. However, this consolidation process requires the flow of water between saturated and unsaturated zones to be considered. The objective of this study is to investigate the stability and consolidation of sediment tailings for the construction of road pillars considering the water flow between saturated and unsaturated zones. The scope of this study includes the unsaturated laboratory testing of sediments and numerical analyses of the road pillar. The results show that the analyses based on saturated conditions overestimate the time required to achieve a 90% degree of consolidation. The incorporation of the unsaturated soil properties is able to optimize the design of slopes for road pillars into steeper slope angles
Self-Preservation of Turbulence Statistics in the Wall-Wake Flow of a Bed-Mounted Horizontal Pipe
Get PDFYesThis research article analyzed the self-preserving behaviour of wall-wake region of a circular pipe mounted horizontally over a flat rigid sand bed in a shallow flow in terms of mean velocity, RSS, and turbulence intensities. The study aims to investigate self-preservation using appropriate length and velocity scales.in addition to that wall-normal distributions of the third-order correlations along the streamwise direction in the wake region are analyzed. An ADV probe was used to record the three-dimensional instantaneous velocities for four different hydraulic and physical conditions corresponding to four cylinder Reynolds numbers. The results revealed that the streamwise velocity deficits, RSS deficits, and turbulence intensities deficits distributions displayed good collapse on a narrow band when they were non-dimensionalized by their respective maximum deficits. The wall-normal distance was non-dimensionalized by the half velocity profile width for velocity distributions, while the half RSS profile width was used in the case of the RSS deficits and turbulence intensities deficits distributions. The results indicate the self-preserving nature of streamwise velocity, RSS, and turbulence intensities in the wall-wake region of the pipe. The third-order correlations distributions indicate that sweep is the dominant bursting event in the near-bed zone. At the same time, ejection is the dominant bursting event in the region above the cylinder height
Infobiotics Workbench: An In Silico Software Suite for Computational Systems Biology
Get PDFYesThis chapter presents the Infobiotics Workbench (IBW), an integrated software suite developed for computational systems biology. The tool is built upon stochastic P systems, a probabilistic extension of P systems, as modelling framework. The platform utilises computer-aided modelling and
analysis of biological systems through simulation, verification and optimisation. IBW allows modelling and analysing not only cell level behaviour, but also multi-compartmental population dynamics. This enables comparing be tween macroscopic and mesoscopic interpretations of molecular interaction
networks and investigating temporo-spatial phenomena in multicellular systems. These capabilities make IBW a useful, coherent and comprehensive in silico tool for systems biology research
Functional and performance analysis of discrete event network simulation tools
Get PDFYesResearchers have used the simulation technique to develop new networks and test, modify, and optimize existing ones. The scientific community has developed a wide range of network simulators to fulfil these objectives and facilitate this creative process. However, selecting a suitable simulator appropriate for a given purpose requires a comprehensive study of network simulators. The current literature on network simulators has limitations. Limited simulators have been included in the studies with functional and performance criteria appropriate for comparison not been considered, and a reasonable selection model for selecting the suitable simulator has not been presented. To overcome these limitations, we studied twenty-three existing network simulators with classifications, additional comparison parameters, system limitations, and comparisons using several criteria.This work was supported by the Petroleum Technology Development Fund (PTDF) Nigeria with grant number PTDF/ED/PHD/MAS/179/17
A single-centre experience of implementing a rapid CXR reporting and CT access pathway for suspected lung cancer: Initial outcomes
Get PDFYesLung cancer remains a major cause of preventable death and early diagnosis is critical to improving survival chances. The chest X-ray (CXR) remains the most common initial investigation, but clinical pathways need to support timely diagnosis through, where necessary, escalation of abnormal findings to ensure priority reporting and early CT scan.
This single-centre study included a retrospective evaluation of a rapid lung cancer CXR pathway in its first year of operation (May 2018-April 2019). The pathway was initially designed for primary care referrals but could also be used for any CXR demonstrating abnormal findings. A parallel cross-sectional survey of radiographers explored their understanding, adherence and concerns regarding their role in the pathway operation.
Primary care referrals on the rapid diagnostic pathway were low (n = 51/21,980; 0.2%), with 11 (21.6%) requiring a CT scan. A further 333 primary care CXR were escalated by the examining radiographer, with 100 (30.0%) undergoing a CT scan. Overall, 64 of the CT scans (57.7%) were abnormal or demonstrated suspicious findings warranting further investigation. There were 39 confirmed primary lung carcinomas, most with advanced disease. Survey responses showed that most radiographers were familiar with the pathway but some expressed concerns regarding their responsibilities and limited knowledge of CXR pathologies.
This baseline evaluation of the rapid lung cancer pathway demonstrated poor referral rates from primary care and identified the need for improved engagement. Radiographer escalation of abnormal findings is an effective adjunct but underlines the need for appropriate awareness, training, and ongoing support.
Engagement of the multiprofessional team is critical in new pathway implementation. Rapid diagnostic pathways can enable early diagnosis and the radiographer has a key role to play in their success
The feasibility of patient reported outcome measures for the care of penile cancer
Get PDFYesWhen used in routine clinical practice, Patient Reported Outcomes Measures (PROMS) can give patients tacit approval to discuss embarrassing topics, which could be particularly useful for urological nursing. The aim of this study was to assess whether it would be feasible to use two such measures for penile cancer; one for body image (the Male Genital Self-Image Scale; MGSIS-5) and another for lymphedema (the Groin and Lower Limb Lymphedema questionnaire; G3L-20). Study packs were posted to penile cancer patients who had received (i) sentinel node biopsy only, (ii) inguinal node dissection only, and (iii) inguinal node dissection with post-operative radiotherapy with or without chemotherapy. The two measures (MGSIS-5 and G3L-20) were complemented with those specific to sexual function (IIEF) and cancer (EORTC-QLQ-C30 version 3) and a modified Lymphoedema Genitourinary Cancer Questionnaire (mLGUCQ). Twenty patients returned questionnaires. Validity and reliability analyses are presented but low participant numbers mean that results need treating with caution. Results show sufficient feasibility for the MGSIS-5 and the G3L-20 to warrant another study to attract larger numbers of participants, either over a longer time frame or at multiple sites. In these further studies, we would recommend adding (1) more Likert responses, (2) the timeframe to the MGIS and (3) exploring either the use of sexual desire psychometric measures or the addition of sexual desire items to the MGSIS for this patient group
Defect prediction on production line
Get PDFYesQuality control has long been one of the most challenging fields of manufacturing. The development of advanced sensors and the easier collection of high amounts of data designate the machine learning techniques as a timely natural step forward to leverage quality decision support and manufacturing challenges. This paper introduces an original dataset provided by the automotive supplier company VALEO, coming from a production line, and hosted by the École Normale Supérieure (ENS) Data Challenge to predict defects using non-anonymised features, without access to final test results, to validate the part status (defective or not). We propose in this paper a complete workflow from data exploration to the modelling phase while addressing at each stage challenges and techniques to solve them, as a benchmark reference. The proposed workflow is validated in series of experiments that demonstrate the benefits, challenges and impact of data science adoption in manufacturing