Petros Papapanagiotou

A theorem proving framework for the formal verification of Web Services Composition

We present a rigorous framework for the composition of Web Services within a higher order logic theorem prover. Our approach is based on the proofs-as-processes paradigm that enables inference rules of Classical Linear Logic (CLL) to be translated into pi-calculus processes. In this setting, composition is achieved by representing available web services as CLL sentences, proving the requested composite service as a conjecture, and then extracting the constructed pi-calculus term from the proof. Our framework, implemented in HOL Light, not only uses an expressive logic that allows us to incorporate multiple Web Services properties in the composition process, but also provides guarantees of soundness and correctness for the composition.

Diagrammatically-Driven formal verification of web-services composition

This paper describes a diagrammatic approach to the formal verification of web-services composition. We present a set of graphical composition rules that map to proof steps in Classical Linear Logic (CLL) and can be used to drive the proof assistant HOL Light purely through interactive, diagrammatic reasoning. The end result is a verified, workflow-like diagram that provides a visual account of the composition process and of the information flow between the services making up the composite service. Our approach thus removes the need to interact directly with HOL Light and provides a mean of visualising and carrying out the whole verification process at an intuitive, yet fully rigorous, level.

Rigorous process-based modelling of patterns for collaborative work in healthcare teams

We review recently proposed notions of healthcare patterns for collaborative work and show how these can be cast in terms of composition of processes. The approach uses a purely diagrammatic language to drive a logic-based verification engine, resulting in fully-verified workflows that capture the information flow in these patterns.

Formal verification of collaboration patterns in healthcare

We propose a computer-based framework for the formal verification of collaboration patterns in healthcare teams. In this, the patterns are constructed diagrammatically as compositions of keystones that are viewed as abstract processes. The approach provides mechanisms for ensuring that safety properties are enforced and exceptional events are handled systematically. Additionally, a fully verified, executable model is obtained as an end product, enabling a simulation of its associated collaboration scenarios.

A Workflow-Driven Formal Methods Approach to the Generation of Structured Checklists for Intrahospital Patient Transfers

Intrahospital transfers are a common but hazardous aspect of hospital care, with a large number of incidents posing a threat to patient safety. A growing body of work advocates the use of checklists for minimizing intrahospital transfer risk, but the majority of existing checklists are not guaranteed to be error-free and are difficult to adapt to different clinical settings or changing hospital policies. This paper details an approach that addresses these challenges through the employment of workflow technologies and formal methods for generating structured checklists. A three-phased methodology is proposed, where intrahospital transfer processes are first conceptualized, then rigorously composed into workflows that are mechanically verified, and finally, translated into a set of checklists that support hospital staff while maintaining the dependencies between different transfer tasks. A case study is presented, highlighting the feasibility of this approach, and the correctness and maintainability benefits brought by the logical underpinning of this methodology. A checklist evaluation is discussed, with promising results regarding their usefulness.

Tracheostomy Transfers: A Case Study in the Application of Formal Methods to Intra-hospital Patient Transfers

We review a generic framework for rigorous workflow modelling and verification that was recently applied to healthcare collaboration patterns, and we show how it can be utilised to help both medical staff and health informaticians build a systematic understanding of informal practices followed during intra-hospital patient transfers. A case study is discussed, demonstrating how the logical foundations of our approach help capture and enforce significant aspects of intra-hospital transfers that are pertinent to their improvement.

Modelling and Implementation of Correct by Construction Healthcare Workflows

We present a rigorous methodology for the modelling and implementation of correct by construction healthcare workflows. It relies on the theoretical concept of proofs-as-processes that draws a connection between logical proofs and process workflows. Based on this, our methodology offers an increased level of trust through mathematical guarantees of correctness for the constructed workflows, including type correctness, systematic resource management, and deadlock and livelock freedom. Workflows are modelled as compositions of abstract processes and can be deployed as executable code automatically. We demonstrate the benefits of our approach through a prototype system involving workflows for assignment and delegation of clinical services while tracking responsibility and accountability explicitly.

Machine Learning for Inductive Theorem Proving.

Over the past few years, machine learning has been successfully combined with automated theorem provers to prove conjectures from proof assistants. However, such approaches do not usually focus on inductive proofs. In this work, we explore a combination of machine learning, a simple Boyer-Moore model and ATPs as a means of improving the automation of inductive proofs in the proof assistant HOL Light. We evaluate the framework using a number of inductive proof corpora. In each case, our approach achieves a higher success rate than running ATPs or the Boyer-Moore tool individually.

Towards Executable Representations of Social Machines

Human interaction is increasingly mediated through technological systems, resulting in the emergence of a new class of socio-technical systems, often called Social Machines. However, many systems are designed and managed in a centralised way, limiting the participants’ autonomy and ability to shape the systems they are part of.

Designing a Social Machine for the Heart Manual Service

Social machines are emerging as a focus of research within the field of informatics as they begin to become the central administrator of our everyday communications. The difficulty of applying such systems to specialised contexts, such as healthcare, calls for guidelines on how to design them, so that they become truly useful. In collaboration with the Heart Manual Department, this project is an attempt at finding suitable methods for designing social machines in a healthcare context. It suggests that adopting a participatory approach where stakeholders are active, equal participants throughout the design process leads to a more usable, likeable, and thus more successful social machine. We describe the process of designing a social machine for the Heart Manual service, in which requirements were elicited through various participatory design methods and a proof of concept evaluation was carried out with a prototype. The prototype was received largely positively and scored highly on the System Usability Scale, indicating the success of the proposed methodology.