The Bayes Factor is a Bayesian tool for comparing two hypotheses, which is gaining popularity in psychological research and being suggested to replace classical t-tests. However, the Bayes Factor requires the specification of a prior distribution for the parameter of interest, which cannot be done unambiguously. In many situations, when further research is needed, information is not complete. This problem can be solved in the context of imprecise probabilities by using only the available (incomplete) knowledge. In this approach, a set of prior distributions is used instead of a single prior, yielding a set of Bayes Factor results, which is called the Robust Bayes Factor. In my talk, I will present the result of a project, in which the Bayes Factor was generalized to imprecise probabilities in a two-sample context with normally distributed data. The effect size between the two groups serves as parameter of interest and its prior was modeled as a set of normal distributions.
Imprecise Tuesdays: Robust Bayes Factor.
Imprecise Tuesdays: Minimisation of the effect of aleatory uncertainties on dynamic systems by active control using the method of receptances.
This paper presents a method to reduce the effect of uncertainties on dynamic systems by means of active control. In the proposed approach, pole placement is performed iteratively using an optimisation algorithm with an objective function that includes the variance of the real and imaginary part of each of the system’s pole. The method is advantageous in that control gains are calculated using the method of receptances, which eliminates model form uncertainty since only measured receptance data is used. Moreover, variances are extracted through a polynomial chaos expansion, which requires fewer samples as opposed to other techniques. The method is demonstrated numerically on a simple multi-degree-of-freedom system. It is shown that active control can be used in a way that not only places the poles of the system but also reduces their spread. Furthermore, it is shown that it is possible to directly relate uncertainty in the poles to meaningful physical based uncertainty in the structural parameters.
The Liverpool Institute for Risk and Uncertainty will host on campus the Annual Showcase Conference on Wednesday September 26th. This is supported by EPSRC & ESRC Centre for Doctoral Training (CDT). In this conference our Students will present their research progress to step up onto their PhD status. Further, there will be a poster competition open to all PhD students of the Risk Institute. This is an opportunity to see the current research pursued at the CDT and Institute for Risk and Uncertainty.
To register for this event, please email Andrea Jones (firstname.lastname@example.org) with the following details: Email address, Name, Organisation and Dietary requirements. Students can also provide their tentative poster title and oral presentation.
Risk Tradeoffs: Crying over Raw Milk
Humans depend on a diverse, protective microflora of bacteria. Some argue that pasteurisation of milk robs consumers of essential heath benefits. Others worry that raw milk can carry disease bacteria leading to illness or even death. Scientific evidence documents both benefits and risks associated with drinking raw milk, but public health authorities often emphasise on risks. Is this smart?
The 8th SIPTA Summer School took place in Oviedo (Spain) from 24 to 28 of July, 2018. It introduced both the main theoretical aspects of imprecise probability models and in particular belief functions, as well as their applications on machine learning, decision making and engineering. Leading specialists in these different aspects of imprecise probabilities gave lectures on the main concepts and techniques associated to their area of expertise, in a friendly environment favouring interaction between participants.
REC2018 was the eighth biennial meeting in the Reliable Engineering Computing series. Hosted by the Liverpool Institute for Risk and Uncertainty, the theme was "Computing with Confidence", bringing together engineers and scientists of all kinds from across industrial, academic and governmental institutions.
As part of the Open Lecture Series, Professor Richard Clegg (Foundation Chief Executive, Lloyd's Register) gives a talk which takes a sideways look at risk from the angle of public perceptions versus reality. It looks at the data behind the hazards and dangers we experience in everyday life, and the psychology of why we seem to accept and tolerate some risks but not others. The talk also compares risks by drawing analogies – for example how many bananas do you need to eat to get the same radiation dose from natural potassium-40 as you do from a dental X-ray?
As part of the Open Lecture Series, Alex Brazier (Director, Financial Stability Strategy and Risk (FSSR), Bank of England) gives a talk regarding economic risk.
As part of the Open Lecture Series, Dr Veronica Bowman (Defence Science and Technology Laboratory) gives a talk providing an illustrative scenario examining the theoretical release and spread of a disease within a city, demonstrating both the challenges faced in such a complex scenario and sharing current best practice when communicating with decision makers.
As part of the Open Lecture Series, Professor Roger Street (University of Oxford) gives a talk on 'The value of uncertainty in decision making: challenges and lessons learnt from addressing climate change'.
The Study Group is an opportunity for industry to gain access to UK excellence in the fields of mathematics, statistics, engineering, and computer science. The structure of the Group allows for this to be done in a structured, intense session over three days.