1,846 research outputs found
P.G. Fookes, E.M. Lee et J.S. Griffiths, Engineering Geomorphology — Theory and practice
No full textAprès la parution en 2005 de l’ouvrage « Geomorphology for Engineers », co-édité par P.G. Fookes, E.M. Lee et G. Milligan (voir Géomorphologie : relief, processus, environnement, 2006, 2, 158-160), on est en droit de s’interroger sur la pertinence de ce nouveau manuel, rédigé par P.G. Fookes, E.M. Lee et J.S. Griffiths. La réponse est donnée dès la première phrase de l’avant-propos de Sir Ron Cooke « Engineers under-rate geomorphology at their peril; geomorphologists ignore their potential va..
P.G. Fookes, E.M. Lee et J.S. Griffiths, Engineering Geomorphology — Theory and practice
No full textAprès la parution en 2005 de l’ouvrage « Geomorphology for Engineers », co-édité par P.G. Fookes, E.M. Lee et G. Milligan (voir Géomorphologie : relief, processus, environnement, 2006, 2, 158-160), on est en droit de s’interroger sur la pertinence de ce nouveau manuel, rédigé par P.G. Fookes, E.M. Lee et J.S. Griffiths. La réponse est donnée dès la première phrase de l’avant-propos de Sir Ron Cooke « Engineers under-rate geomorphology at their peril; geomorphologists ignore their potential va..
Report prepared for the Ministry of Agriculture, Fisheries and Food under a contract to study wave/current interaction
No full textOn the reliability of the Autosub autonomous underwater vehicle
No full textAs autonomous underwater vehicles (AUVs) enter operational service an assessment of their reliability is timely. Using the Autosub AUV as an example, several design issues affecting reliability are discussed, followed by an analysis of recorded faults. Perhaps contrary to expectations, failures rarely involved the autonomous nature of the vehicle. Rather, faults were typical of those that occur with any complex item of marine electromechanical equipment. A statistical analysis showed that the failure rate decreased with distance travelled- an indicator that an AUV underway, submerged, is at less risk of a fault developing than during other phases of a mission. 1
Quantum Griffiths Inequalities
No full textWe present a general framework of Griffiths inequalities for quantum systems. Our approach is based on operator inequalities associated with self-dual cones and provides a consistent viewpoint of the Griffiths inequality. As examples, we discuss the quantum Ising model, quantum rotor model, Bose-Hubbard model, and Hubbard model. We present a model-independent structure that governs the correlation inequalities
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Gaming addiction in adolescence (revisited)
No full textGaming addiction has become a topic of increasing research interest. Over the last 25 years, I have written many articles on adolescent video gaming for Education and Health as it is one of the research fields that is constantly evolving. In fact, over the last decade, there has been a significant increase in the number of scientific studies examining various aspects of online addiction particularly among adolescents and young adults (Kuss & Griffiths, 2012; Kuss, Griffiths, Karila & Billieux, 2014). Although the amount and the quality of research in the field has progressed much over this period, it is still in its infancy compared to other more established behavioural addictions (such as pathological gambling). This article briefly examines (i) how adolescent gaming addiction research has changed over the last three decades, (ii) how online gaming addiction has gained genuine psychiatric status, (iii) excessive gaming as an addiction, and (iv) where the gaming addiction field is going
A Markov Chain state transition approach to establishing critical phases for AUV reliability
No full textThe deployment of complex autonomous underwater platforms for marine science comprises a series of sequential steps. Each step is critical to the success of the mission. In this paper we present a state transition approach, in the form of a Markov chain, which models the sequence of steps from pre-launch to operation to recovery. The aim is to identify the states and state transitions that present higher risk to the vehicle and hence to the mission, based on evidence and judgment. Developing a Markov chain consists of two separate tasks. The first defines the structure that encodes the sequence of events. The second task assigns probabilities to each possible transition. Our model comprises eleven discrete states, and includes distance-dependent underway survival statistics. The integration of the Markov model with underway survival statistics allows us to quantify the likelihood of success during each state and transition and consequently the likelihood of achieving the desired mission goals. To illustrate this generic process, the fault history of the Autosub3 autonomous underwater vehicle provides the information for different phases of operation. The method proposed here adds more detail to previous analyses; faults are discriminated according to the phase of the mission in which they took place
Results of expert judgments on the faults and risks with Autosub3 and an analysis of its campaign to Pine Island Bay, Antarctica, 2009
No full textProbabilistic risk assessment is a methodology that can be systematically applied to estimate the risk associated with the design and operation of complex systems. The National Oceanography Centre, Southampton, UK has developed a risk management process tailored to the operation of autonomous underwater vehicles. Central to the application of the risk management process is a probabilistic risk assessment. The risk management process was applied to estimate the risk associated with an Autosub3 science campaign in the Pine Island Glacier, Antarctica, and to support decision making. The campaign was successful. In this paper we present the Autosub3 risk model and we show how this model was used to assess the campaign risk
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