scholarly journals A Behavioral Probabilistic Risk Assessment Framework for Managing Autonomous Underwater Vehicle Deployments

2012 ◽  
Vol 29 (11) ◽  
pp. 1689-1703 ◽  
Author(s):  
Mario Brito ◽  
Gwyn Griffiths ◽  
James Ferguson ◽  
David Hopkin ◽  
Richard Mills ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Autonomous Underwater Vehicle ◽  
Risk Mitigation ◽  
Operational Risk ◽  
Maximum Error ◽  
Underwater Vehicle ◽  
Behavioral Approach ◽  
Mitigation Measures ◽  
The Arctic ◽  
Deep Diving

Abstract The deployment of a deep-diving long-range autonomous underwater vehicle (AUV) is a complex operation that requires the use of a risk-informed decision-making process. Operational risk assessment is heavily dependent on expert subjective judgment. Expert judgments can be elicited either mathematically or behaviorally. During mathematical elicitation experts are kept separate and provide their assessment individually. These are then mathematically combined to create a judgment that represents the group view. The limitation with this approach is that experts do not have the opportunity to discuss different views and thus remove bias from their assessment. In this paper, a Bayesian behavioral approach to estimate and manage AUV operational risk is proposed. At an initial workshop, behavioral aggregation, that is, reaching agreement on the distributions of risks for faults or incidents, is followed by an agreed upon initial estimate of the likelihood of success of the proposed risk mitigation methods. Postexpedition, a second workshop assesses the new data and compares observed to predicted risk, thus updating the prior estimate using Bayes’ rule. This feedback further educates the experts and assesses the actual effectiveness of the mitigation measures. Applying this approach to an AUV campaign in ice-covered waters in the Arctic showed that the maximum error between the predicted and the actual risk was 9% and that the experts’ assessments of the effectiveness of risk mitigation led to a maximum of 24% in risk reduction.

Adaptive Sampling of Surface Fronts in the Arctic Using an Autonomous Underwater Vehicle

2021 ◽  
pp. 1-10
Author(s):  
Trygve Olav Fossum ◽  
Petter Norgren ◽  
Ilker Fer ◽  
Frank Nilsen ◽  
Zoe Koenig ◽  
...  
Keyword(s):  
Adaptive Sampling ◽  
Autonomous Underwater Vehicle ◽  
Underwater Vehicle ◽  
The Arctic

Development of An Exposure Model for Bridge Structures in Northern Algeria

2018 ◽  
Author(s):  
Andrés Abarca ◽  
Ricardo Monteiro
Keyword(s):  
Risk Assessment ◽  
Large Scale ◽  
Risk Mitigation ◽  
Regional Scale ◽  
Mitigation Measures ◽  
Exposure Model ◽  
Building Stock ◽  
Earthquake Scenarios ◽  
Northern Algeria ◽  
Bridge Structures

In recent years, the use of large scale seismic risk assessment has become increasingly popular to evaluate the fragility of a specific region to an earthquake event, through the convolution of hazard, exposure and vulnerability. These studies tend to focus on the building stock of the region and sometimes neglect the evaluation of the infrastructure, which has great importance when determining the ability of a social group to attend to a disaster and to eventually resume normal activities. This study, developed within the scope of the EU-funded project ITERATE (Improved Tools for Disaster Risk Mitigation in Algeria), focuses on the proposal of an exposure model for bridge structures in Northern Algeria. The proposed model was developed using existing national data surveys, as well as satellite information and field observations. As a result, the location and detailed characterization of a significant share of the Algeria roadway bridge inventory was developed, as well as the definition of a taxonomy that is able to classify the most common structural systems used in Algerian bridge construction. The outcome of this study serves as input to estimate the fragility of the bridge infrastructure inventory and, furthermore, to the overall risk assessment of the Northern Algerian region. Such fragility model will, in turn, enable the evaluation of earthquake scenarios at a regional scale and provide valuable information to decision makers for the implementation of risk mitigation measures.

Credit Risk Management of Commercial Banks in Nepal

2019 ◽  
Vol 4 (1) ◽  
pp. 27-37
Author(s):  
Shreya Pradhan ◽  
Ajay K. Shah
Keyword(s):  
Risk Assessment ◽  
Risk Management ◽  
Credit Risk ◽  
Commercial Banks ◽  
Management Practices ◽  
Risk Mitigation ◽  
Mitigation Measures ◽  
Credit Risk Management ◽  
Loan Repayment ◽  
Credit Risk Assessment

The study is primarily focused on credit risk assessment practices in commercial banks on the basis of their internal efficiency, assessment of assets and borrower. The model of the study is based on the analysis of relationship between credit risk management practices, credit risk mitigation measures and obstacles and loan repayment. Based on a descriptive research approach the study has used survey-based primary data and performed a correlation analysis on them. It discovered that credit risk management practices and credit risk mitigation measures have a positive relationship with loan repayment, while obstacles faced by borrowers have no significant relationship with loan repayment. The study findings can provide good insights to commercial bank managers in analysing their model of credit risk management system, policies and practices, and in establishing a profitable and sustainable model for credit risk assessment, by setting a risk tolerance level and managing credit risks vis-a-vis the prevailing market competition.

Deep diving with Clio

2020 ◽  
Vol 5 (48) ◽  
pp. eabf1499
Author(s):  
Jnaneshwar Das ◽  
Elizabeth Trembath-Reichert
Keyword(s):  
Autonomous Underwater Vehicle ◽  
Underwater Vehicle ◽  
Ocean Basin ◽  
Deep Diving ◽  
Basin Scale

An autonomous underwater vehicle, named Clio, can sample ocean basin–scale biogeochemistry at depths up to 6000 meters.

scholarly journals Updating Autonomous Underwater Vehicle Risk Based on the Effectiveness of Failure Prevention and Correction

2018 ◽  
Vol 35 (4) ◽  
pp. 797-808 ◽  
Author(s):  
Mario P. Brito ◽  
Gwyn Griffiths
Keyword(s):  
Autonomous Underwater Vehicle ◽  
Risk Mitigation ◽  
Autonomous Underwater Vehicles ◽  
Underwater Vehicle ◽  
Underwater Vehicles ◽  
Probability Of Failure ◽  
Risk Profile ◽  
Failure Prevention ◽  
Significant Difference

AbstractAutonomous underwater vehicles (AUVs) have proven to be feasible platforms for marine observations. Risk and reliability studies on the performance of these vehicles by different groups show a significant difference in reliability, with the observation that the outcomes depend on whether the vehicles are operated by developers or nondevelopers. This paper shows that this difference in reliability is due to the failure prevention and correction procedures—risk mitigation—put in place by developers. However, no formalization has been developed for updating the risk profile based on the expected effectiveness of the failure prevention and correction process. A generic Bayesian approach for updating the risk profile is presented, based on the probability of failure prevention and correction and the number of subsequent deployments on which the failure does not occur. The approach, which applies whether the risk profile is captured in a parametric or nonparametric survival model, is applied to a real case study of the International Submarine Engineering Ltd. (ISE) Explorer AUV.

Arc flash: a risk assessment and mitigation strategy

2011 ◽  
Vol 51 (2) ◽  
pp. 737
Author(s):  
Danny Norton ◽  
Dale Wright
Keyword(s):  
Risk Assessment ◽  
Oil And Gas ◽  
Capital Expenditure ◽  
Risk Mitigation ◽  
Cumulative Effect ◽  
Mitigation Strategy ◽  
Assessment Process ◽  
Mitigation Measures ◽  
Safe Work ◽  
Arc Flash

Oil and gas facility managers are well aware that attention to detail saves lives and supports business continuity and reputation. Those tasked with stewardship of electrical assets will be aware of the need to protect their employees from the hazard of electrical arc flash and that it should be at the forefront of safety thinking. Complacency and lack of duty of care with this real and possibly un-quantified hazard can lead to fatalities. The primary solution to arc flash consequences in older installations has been the implementation of safe work procedures and personal protective equipment. While still valid, these solutions are the least effective options in the hierarchy of controls. SKM have developed a practical risk mitigation strategy that considers the hazards of prospective arc flash energy together with the cumulative effect of switchboard age, design, capability and condition. The strategy also considers the range of potential mitigation controls available through the mechanism of substitution and engineering design that focuses on reducing: The likelihood of an arc flash incident occurring; The likelihood of personnel exposure; and, The energy released should an incident occur. A structured arc flash risk assessment process can provide the asset owner the opportunity to rank individual switchboards for likelihood, consequence and risk, and thus provide direction for engineered remediation and capital expenditure. SKM proposes the way in which arc flash risk can be assessed, how appropriate layered mitigation measures might be selected, and how an asset owner may approach the issue of arc flash hazard mitigation to economically and reliably protect its employees.

scholarly journals Lessons learned from China’s mitigation strategies in fighting COVID-19

2021 ◽  
Vol 292 ◽  
pp. 03088
Author(s):  
Sijiang Liu ◽  
Mingyuan Wan
Keyword(s):  
Public Health ◽  
Risk Mitigation ◽  
Arctic Region ◽  
Lessons Learned ◽  
Mitigation Strategies ◽  
World Health ◽  
Mitigation Measures ◽  
The Arctic ◽  
Health Complications ◽  
Health Organization

In late 2019, the first SARS-CoV-2 case was reported in Wuhan, China. It has been known as a deadly virus that could cause many severe health complications, particularly respiratory illnesses. With its extraordinary ability to transmit between humans, the coronavirus disease 2019 (COVID-19) has spread worldwide, including Antarctica and the Arctic region. On 11th March 2020, the World Health Organization (WHO) declared the COVID-19 as a public health emergency worldwide (global pandemic) to raise global awareness of the dangerous virus. With immediate and efficient public health interventions, progress has been seen in many countries such as China and New Zealand. Therefore, in this review, we summarized the important public health risk mitigation measures applied in China.

Path Following of Underactuated Marine Underwater Vehicles in the Presence of Unknown Ocean Currents

2014 ◽  
Author(s):  
Signe Moe ◽  
Walter Caharija ◽  
Kristin Y. Pettersen ◽  
Ingrid Schjølberg
Keyword(s):  
Oil And Gas ◽  
Autonomous Underwater Vehicle ◽  
Autonomous Underwater Vehicles ◽  
Path Following ◽  
Oil And Gas Industry ◽  
Underwater Vehicle ◽  
Underwater Vehicles ◽  
Ocean Currents ◽  
The Arctic ◽  
Ocean Current

The use of autonomous marine vehicles, and especially autonomous underwater vehicles, is rapidly increasing within several fields of study. In particular, such vehicles can be applied for sea floor mapping, oceanography, environmental monitoring, inspection and maintenance of underwater structures (for instance within the oil and gas industry) and military purposes. They are also highly suitable for operations below ice-covered areas in the Arctic. However, there are still many challenges related to making such underwater vehicles autonomous. A fundamental task of an autonomous underwater vehicle vessel is to follow a general path in the presence of unknown ocean currents. There exist several results for underwater vehicles to follow a general path when no ocean currents are present [1] and to follow a geometrically simple path such as a straight line when ocean currents affect the vehicle [2, 3], but the problem of general path following in the presence of unknown ocean currents has not been solved yet. This paper presents a method to achieve this. The results are an extension of the results in [1], and introduce a virtual Serret-Frenet reference frame that is anchored in and propagates along the desired path. The closed-loop system consists of an ocean current observer, a guidance law, a controller and an update law to drive the Serret-Frenet frame along the path, and is shown to be asymptotically stable given that certain assumptions are fulfilled. This guarantees that the autonomous underwater vehicle will converge to the desired path and move along it with the desired velocity. Simulation results are presented to verify and illustrate the theoretical results.

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