Physical Behaviours for Trust Assessment in Autonomous Underwater MANETs

This paper proposes a new approach to determine trust in resource-constrained networks of autonomous systems based on their physical behaviour, using the motion of nodes within a team to detect and identify malicious or failing operation within their cohort. This is accomplished by looking at operations in the underwater marine environment. We present a series of composite metrics based on physical movement, and apply these metrics to the detection and discrimination of sample physical misbehaviours. This approach opens the possibility of bringing information about both the physical and communications behaviours of autonomous MANETs together to strengthen and expand the application of future Trust Management Frameworks in sparse and/or resource constrained environment

Elimination of the reaction rate 'scale effect': application of the Lagrangian reactive particle-tracking method to simulate mixing-limited, field-scale biodegradation at the Schoolcraft (MI, USA) site

This is the peer reviewed version of the following article: [Ding, D., Benson, D. A., Fernàndez‐Garcia, D., Henri, C. V., Hyndman, D. W., Phanikumar, M. S., & Bolster, D. (2017). Elimination of the reaction rate “scale effect”: Application of the Lagrangian reactive particle‐tracking method to simulate mixing‐limited, field‐scale biodegradation at the Schoolcraft (MI, USA) site. Water Resources Research, 53, 10,411–10,432. https://doi.org/10.1002/2017WR021103], which has been published in final form at https://doi.org/10.1002/2017WR021103. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.Measured (or empirically fitted) reaction rates at groundwater remediation sites are typically much lower than those found in the same material at the batch or laboratory scale. The reduced rates are commonly attributed to poorer mixing at the larger scales. A variety of methods have been proposed to account for this scaling effect in reactive transport. In this study, we use the Lagrangian particle-tracking and reaction (PTR) method to simulate a field bioremediation experiment at the Schoolcraft, MI site. A denitrifying bacterium, Pseudomonas Stutzeri strain KC (KC), was injected to the aquifer, along with sufficient substrate, to degrade the contaminant, carbon tetrachloride (CT), under anaerobic conditions. The PTR method simulates chemical reactions through probabilistic rules of particle collisions, interactions, and transformations to address the scale effect (lower apparent reaction rates for each level of upscaling, from batch to column to field scale). In contrast to a prior Eulerian reaction model, the PTR method is able to match the field-scale experiment using the rate coefficients obtained from batch experiments.Peer ReviewedPostprint (author's final draft

Use of Annual Phosphorus Loss Estimator (APLE) Model to Evaluate a Phosphorus Index

The Phosphorus (P) Index was developed to provide a relative ranking of agricultural fields according to their potential for P loss to surface water. Recent efforts have focused on updating and evaluating P Indices against measured or modeled P loss data to ensure agreement in magnitude and direction. Following a recently published method, we modified the Maryland P Site Index (MD-PSI) from a multiplicative to a component index structure and evaluated the MD-PSI outputs against P loss data estimated by the Annual P Loss Estimator (APLE) model, a validated, field-scale, annual P loss model. We created a theoretical dataset of fields to represent Maryland conditions and scenarios and created an empirical dataset of soil samples and management characteristics from across the state. Through the evaluation process, we modified a number of variables within the MD-PSI and calculated weighting coefficients for each P loss component. We have demonstrated that our methods can be used to modify a P Index and increase correlation between P Index output and modeled P loss data. The methods presented here can be easily applied in other states where there is motivation to update an existing P Index

Effect of spatial concentration fluctuations on effective kinetics in diffusion-reaction systems

International audienceThe effect of spatial concentration fluctuations on the reaction of two solutes, A þ B* C, is considered. In the absence of fluctuations, the concentration of solutes decays as Adet ¼ Bdet t 1. Contrary to this, experimental and numerical studies suggest that concentrations decay significantly slower. Existing theory suggests a t d/4 scaling in the asymptotic regime (d is the dimensionality of the problem). Here we study the effect of fluctuations using the classical diffusion-reaction equation with random initial conditions. Initial concentrations of the reactants are treated as correlated random fields.We use the method of moment equations to solve the resulting stochastic diffusion-reaction equation and obtain a solution for the average concentrations that deviates from t 1 to t d/4 behavior at characteristic transition time t . We also derive analytical expressions for t as a function of Damköhler number and the coefficient of variation of the initial concentration

Probabilistic analysis of groundwater-related risks at subsurface excavation sites

      Construction of underground structures (e.g., subway lines, railways and highway tunnels) is inherently hazardous, posing risks to both workers and machinery at the site and to surrounding buildings. The presence of groundwater may increase these risks. We develop a general probabilistic risk assessment (PRA) framework to quantify risks driven by groundwater to the safety of underground constructions. The proposed approach is fully compatible with standard PRA practices, employing well-developed risk analysis tools based on the fault tree analysis method. The novelty and computational challenges of the proposed approach stem from the reliance on a combination of approaches including extracting information from databases, solving stochastic differential equations, or relying on expert judgment to compute probabilities of basic events. The general framework is presented in a case study and used to estimate and minimize risks at a construction site of an underground station for a new subway line in the Barcelona metropolitan area. &nbsp

Suicide care from the nursing perspective: a meta‐synthesis of qualitative studies

Aims: to explore nurses' experiences of suicide care and to identify and synthesize the most suitable interventions for the care of people with suicidal behaviour from a nursing perspective. Design: qualitative meta-synthesis. Data sources: comprehensive search of five electronic databases for qualitative studies published between January 2015 and June 2019. Review methods: the PRISMA statement was used for reporting the different phases of the literature search and the Critical Appraisal Skills Programme (CASP) qualitative research checklist was used as an appraisal framework. Data synthesis was conducted using Sandelowski and Barroso's method. Results: seventeen articles met the inclusion criteria. The data analysis revealed 13 subcategories from which four main categories emerged: 'Understanding suicidal behaviour as a consequence of suffering', 'Nurses' personal distress in suicide care', 'The presence of the nurse as the axis of suicide care' and, 'Improving nurses' relational competences for a better therapeutic environment'. Conclusion: further training of nurses on the therapeutic relationship, particularly in non-mental health care work settings, and monitoring of the emotional impact on nurses in relation to suicide is required to promote more effective prevention and care. Impact: this review provides new insights on how suicide is interpreted, the associated emotions, the way suicide is approached and proposals for improving clinical practice from the point of view of nurses. The results demonstrate that the nurse-patient relationship, ongoing assessment, and the promotion of a sense of security and hope are critical in nursing care for patients who exhibit suicidal behaviour. Consequently, to promote an effective nursing care of suicide, nurses should be provided with further training on the therapeutic relationship. Thus, health institutions do not only provide the time and space to conduct an adequate therapeutic relationship, but also, through their managers, they should supervise and address the emotional impact that is generated in nurses caring for patients who exhibit suicidal behaviour

Measuring wearing time of knee-ankle-foot orthoses in children with cerebral palsy: comparison of parent-report and objective measurement

Purpose State Orthotic wearing time may be an important confounder in efficacy studies of treatment in children with spastic cerebral palsy (SCP). Most studies measure parent-reported wearing time with questionnaires, but it is questionable whether this yields valid results. This study aims to compare parent-reported wearing time (WTparent) with objectively measured wearing time (WTobj) in children with SCP receiving orthotic treatment. Method Eight children with SCP participated in this observational study. For one year, they received knee-ankle-foot orthosis (KAFO) treatment. WTparent was measured using questionnaires. WTobj was measured using temperature sensor-data-loggers that were attached to the KAFOs. The 2.5th and 97.5th percentiles and median of differences between methods (per participant) were used to calculate limits of agreement and systematic differences. Results There was no systematic difference between WTparent and WTobj (0.1 hours per week), but high inter-individual variation of the difference was found, as reflected by large limits of agreement (lower limit/2.5th percentile: -1.7. hours/week; upper limit/97.5th percentile: 11.1 hours/week). Conclusions Parent-reported wearing time of a knee-ankle-foot orthosis differs largely from objectively measured wearing time using temperature sensors. Therefore, parent-reported wearing time of KAFOs should be interpreted with utmost care