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Talks

Impact of multimorbidity profiles on mortality rates and sepsis: A network approach

    Date: 5th November 2021
    Time: 14:00 - 16:00

    Title: Impact of multimorbidity profiles om mortality rates and sepsis: A network approach
    Speaker: Jorge Gaete Villegas
    Abstract: 

    In this talk I will present the use of the Stochastic Block Model (SBM) as an alternative to clustering techniques to study the impact of multimorbidity on in-hospital sepsis and mortality. The SBM is an approach to community detection that can be used instead of classic clustering techniques such as k-means or Latent Class Analysis (LCA) to identify groups of patients. Since the SBM is a nonparametrical method and makes no assumptions about the features distribution, its application overcomes some of the known limitations of other clustering algorithms. As an added benefit, the SBM provides clusters at different resolutions in a hierarchical structure with potential uses to increase explainability of the results.

    Adverse Drug Reaction Prediction via Network Representation Learning and Multimodal Embedding

      Date: 22nd October 2021
      Time: 14:00 - 16:00

      Title: Adverse Drug Reaction Prediction via Network Representation Learning and Multimodal Embedding
      Speaker: Lauren DeLong
      Abstract: 

      Novel drugs often fail in late-stage clinical trials due to unforeseen adverse side effects which deem them unsafe for distribution. Many computational approaches have aimed to address this issue, but few have attempted to use Network Representation Learning (NRL) algorithms. Some previous approaches take advantage of the concept that similar chemical composition between drugs, should, in turn, indicate similar biochemical function and therefore similar side effects. However, this principle is shown to be violated frequently in clinical practice, such as in the case of Procaine and Procainamide, a local anesthetic and an antiarrhythmic, respectively. In contrast, newer approaches show improved performance with an increased variety of biomedical information. The complex landscape of interactions between drugs, targets, protein-protein interactions and adverse drug reactions (ADRs) can be modeled as a large heterogeneous graph in which nodes represent proteins, drugs, or ADRs, and edges which exist between these varieties of nodes indicate some sort of interaction, such as that a certain drug is associated with a side effect. Network topological measures can provide insight into which drugs are more likely to result in adverse events than others. However, in the context of drug development it is essential to de-risk targets and compounds as early as possible. Hence, it is important to predict adverse events for compounds and unwanted phenotypes for targets. These two problems can be formulated as link prediction tasks in the heterogeneous graph. Technically, this can be addressed via NRL, where an encoder is used to find low dimensional node embeddings and a corresponding decoder is used to assign likelihoods to each of the possible edges in the network. In this work, the Relational Graph Attention Network is extended to operate on multimodal biological input and compared alongside previously established side effect prediction methods to evaluate the efficacy of deep NRL for side effect prediction.

      Verified Optimisation in Lean

        Date: 22nd October 2021
        Time: 14:00 - 16:00

        Title: Verified Optimisation in Lean
        Speaker: Ramon Mir Fernandez
        Abstract: 
        Convex optimisation is a subfield of mathematics that studies convex functions and their maxima/minima over a given domain. It has applications in control synthesis, signal processing and operations research to mention a few. One issue is that reducing these problems to convex optimisation problems is not straightforward and error-prone. Moreover, the approximate nature of the algorithms used by the solvers can make the result unreliable. For these reasons, it would be highly desirable to use a formal tool alongside these solvers to rigorously check every step and certify the final result. We will delve into how the tools can be linked and discuss some work in progress. The formal tool chosen for this project is Lean, a theorem prover and programming language developed at Microsoft Research. We will explain some of its main features and talk about how it differs from other systems such as Coq or Isabelle. Finally, we will explore neural network verification as a potential case study.

        Mechanising Process Composition

          Date: 10th September 2021
          Time: 14:00 - 16:00

          Title: Mechanising Process Composition
          Speaker: Filip Smola
          Abstract: 
          In this talk I will give an overview of progress made on my PhD project and the future plans. The project is centred on processes specified by input and output resource, and their composition. I will give a brief overview of processes and resources, as well as their mechanisation. I will then present four process models we have built that demonstrate some of the features our mechanisation can already express, such as located resources and sensing actions. Then I will go over how we relate the process compositions to proofs in linear logic, giving them a notion of correctness. Finally I will sum up the plans for the future of this project.

          A Formalisation of Markov Decision Processes

            Date: 27th August 2021
            Time: 14:00 - 16:00

            Title: A Formalisation of Markov Decision Processes
            Speaker: Mark Chevallier
            Abstract: 

            In this talk I will discuss my formalisation of Markov Decision Processes. I will talk about the formalised model, formal proofs of value convergence and of the existence of an optimal policy by vector representation of functions on the states. My approach was based on Martin Puterman's proof, and in the process of formalisation I found a small flaw in it, which was addressed and fixed.

            Mapping and Reapplying Mathematical Knowledge

              Date: 16th August 2021
              Time: 14:00 - 16:00

              Title: Mapping and Reapplying Mathematical Knowledge
              Speaker: James Vaughan
              Abstract: 

              There has been little research into the structure present in the litany of formal mathematics generated with interactive theorem provers. Network theory gives us tools to model the dynamics of complex systems, of which formal mathematics undoubtedly qualifies as an instance. I will discuss what we have done in the past year to apply these tools to improve the capabilities of interactive theorem provers. I will also present the plans for the remainder of my PhD.

              Tree Search using Human Expert’s Knowledge

                Date: 16th July 2021
                Time: 14:00 - 16:00

                Title: Tree Search using Human Expert’s Knowledge
                Speaker: Mustafa Faisal Abdelwahed
                Abstract: 

                For a while, tree search algorithms have been used in solving challenging problems like planning problems and combinatorial optimization search. Researchers tend to encode their search parameters or knowledge into objective functions, which receives a state then generates a number to represent how satisfying this state is concerning built-in constraints or a targeted solution configuration while pruning branches with no possible potential. However, they ignored a vital point: transformation/encoding causes information loss, leading to degrading the solution quality and may result in more computational costs. Hence, in the upcoming presentation, we shall explore how we can augment the human experience directly with tree search without encoding them into objective functions.

                Using causal inference to evaluate the efficacy of medicinal treatments from observational data

                  Date: 11th June 2021
                  Time: 14:00 - 16:00

                  Title: Using causal inference to evaluate the efficacy of medicinal treatments from observational data
                  Speaker: Callum Abbott
                  Abstract: 

                  Whether we're talking about COVID vaccines, antibiotics, or painkillers; the efficacy of medicinal treatments has been traditionally tested using the gold-standard Randomized Control Trial (RCT). However, conducting RCTs can often be unfeasible due to ethical, logistical or financial concerns. For instance, what if we needed to know the efficacy of a surgical procedure in treating a fatal neurological condition? We cannot afford to send the control group to their inevitable doom. Hence, in this study, we look to apply causal inference techniques to purely observational data to investigate the effectiveness of subdural drainage in preventing the recurrence of chronic subdural hematoma.

                  Composing Processes in Isabelle

                    Date: 16th April 2021
                    Time: 14:00 - 16:00

                    Title: Composing Processes in Isabelle
                    Speaker: Filip Smola
                    Abstract: 

                    In many domains we are confronted with complex processes, from manufacturing workflows to administrative tasks. When analysing such processes, the formal representations involved can quickly get too large for a human to correctly and efficiently manipulate. My PhD project is on mechanising the notion of process compositions, verifying correctness-preserving methods for constructing them, and demonstrating the applications of the resulting formalism. In this talk I will give an overview of my project and my progress so far. I will present the highlights of my mechanisation in Isabelle and note some of the more interesting choices I made along the way. I will also outline the path forward in the coming months.

                    Productive use of uncertain events in Business Process Management

                      Date: 16th April 2021
                      Time: 14:00 - 16:00

                      Title: Productive use of uncertain events in Business Process Management
                      Speaker: Jiawei Zheng
                      Abstract: 

                      Complex event processing (CEP) and Business Process Management (BPM) have traditionally been researching on distinct application areas, but some novel scenarios would allow to involve the combination of both aspects. Particularly, in the context of Internet of Things (IoT),  CEP is often concerned with low-level events that may related to a specific activity in a business process. Specifically, the events are most often under uncertainty, ranging from erroneous or incomplete data streams to incomplete event detection patterns. There are great challenges and opportunities to integrate CEP into BPM to predict the potential disruptive events and estimate the duration of the process under the uncertainty.