scholarly journals Fuzzy System Dynamics Risk Analysis (FuSDRA) of Autonomous Underwater Vehicle Operations in the Antarctic

Risk Analysis ◽  
2019 ◽  
Vol 40 (4) ◽  
pp. 818-841 ◽  
Author(s):  
Tzu Yang Loh ◽  
Mario P. Brito ◽  
Neil Bose ◽  
Jingjing Xu ◽  
Kiril Tenekedjiev
Science ◽  
2020 ◽  
Vol 368 (6494) ◽  
pp. 1020-1024 ◽  
Author(s):  
J. A. Dowdeswell ◽  
C. L. Batchelor ◽  
A. Montelli ◽  
D. Ottesen ◽  
F. D. W. Christie ◽  
...  

A suite of grounding-line landforms on the Antarctic seafloor, imaged at submeter horizontal resolution from an autonomous underwater vehicle, enables calculation of ice sheet retreat rates from a complex of grounding-zone wedges on the Larsen continental shelf, western Weddell Sea. The landforms are delicate sets of up to 90 ridges, <1.5 meters high and spaced 20 to 25 meters apart. We interpret these ridges as the product of squeezing up of soft sediment during the rise and fall of the retreating ice sheet grounding line during successive tidal cycles. Grounding-line retreat rates of 40 to 50 meters per day (>10 kilometers per year) are inferred during regional deglaciation of the Larsen shelf. If repeated today, such rapid mass loss to the ocean would have clear implications for increasing the rate of global sea level rise.


Author(s):  
Tzu Yang Loh ◽  
Mario P. Brito ◽  
Neil Bose ◽  
Jingjing Xu ◽  
Natalia Nikolova ◽  
...  

The maturing of autonomous technology has fostered a rapid expansion in the use of Autonomous Underwater Vehicles (AUVs). To prevent the loss of AUVs during deployments, existing risk analysis approaches tend to focus on technicalities, historical data and experts’ opinion for probability quantification. However, data may not always be available and the complex interrelationships between risk factors are often neglected due to uncertainties. To overcome these shortfalls, a hybrid fuzzy system dynamics risk analysis (FuSDRA) is proposed. The approach utilises the strengths while overcoming limitations of both system dynamics and fuzzy set theory. Presented as a three-step iterative framework, the approach was applied on a case study to examine the impact of crew operating experience on the risk of AUV loss. Results showed not only that initial experience of the team affects the risk of loss, but any loss of experience in earlier stages of the AUV program have a lesser impact as compared to later stages. A series of risk control policies were recommended based on the results. The case study demonstrated how the FuSDRA approach can be applied to inform human resource and risk management strategies, or broader application within the AUV domain and other complex technological systems.


2012 ◽  
Vol 12 (3) ◽  
pp. 17-26 ◽  
Author(s):  
A. Carrera ◽  
S. R. Ahmadzadeh ◽  
A. Ajoudani ◽  
P. Kormushev ◽  
M. Carreras ◽  
...  

Abstract In this paper an autonomous intervention robotic task to learn the skill of grasping and turning a valve is described. To resolve this challenge a set of different techniques are proposed, each one realizing a specific task and sending information to the others in a Hardware-In-Loop (HIL) simulation. To improve the estimation of the valve position, an Extended Kalman Filter is designed. Also to learn the trajectory to follow with the robotic arm, Imitation Learning approach is used. In addition, to perform safely the task a fuzzy system is developed which generates appropriate decisions. Although the achievement of this task will be used in an Autonomous Underwater Vehicle, for the first step this idea has been tested in a laboratory environment with an available robot and a sensor.


Risk Analysis ◽  
2020 ◽  
Vol 40 (6) ◽  
pp. 1258-1278
Author(s):  
Tzu Yang Loh ◽  
Mario P. Brito ◽  
Neil Bose ◽  
Jingjing Xu ◽  
Kiril Tenekedjiev

Risk Analysis ◽  
2010 ◽  
Vol 30 (12) ◽  
pp. 1771-1788 ◽  
Author(s):  
Mario Paulo Brito ◽  
Gwyn Griffiths ◽  
Peter Challenor

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