From Hybrid Simulation to Hybrid Systems Modelling

This is the author accepted manuscript. The final version is available from IEEE via the DOI in this record.Hybrid Simulation (HS) is the combined application of simulation approaches like SD, DES and ABS in the model implementation stage of a simulation study. Its objective is to better represent the system under scrutiny. Hybrid Systems Modelling (HSM), on the other hand, is the combined application of simulation with methods and techniques from disciplines such as Applied Computing, Computer Science, Engineering and the wider OR. HSM can be applied to multiple stages of a simulation study. In this paper, we present a classification of HS and extend it to include HSM approaches which use simulation with other OR techniques. The paper contributes to the debate on what constitutes HS and offers a unifying conceptual representation for mixing simulation approaches with HSM methods and techniques

The rôle of knowledge in system risk identification and assessment: The 2014 Ebola outbreak

This is the author accepted manuscript. The final version is available from Palgrave Macmillan via the DOI in this recordCurrent approaches to risk management stress the need for dynamic approaches to risk identification aimed at reducing the expected consequences of undesired outcomes. We contend that these approaches place insufficient emphasis on the system knowledge available to the assessor, particularly in respect of three related factors, namely the dynamic behaviour of the system under threat, the role of human agents and the knowledge availability to those agents. In this paper, we address the rôle of knowledge use and availability in critical human activity systems. We emphasise two distinctions: that between information and knowledge used in these systems, and that between knowledge about the system and knowledge deployed within it, the latter forming part of the system itself. Using the ongoing 2014–2015 West African Ebola outbreak as an example, we offer a practical procedure using the well-known systems dynamics technique in its qualitative form for the identification of risks and appropriate policies for managing those risks

RH-RT: A Data Analytics Framework for Reducing Wait Time at Emergency Departments and Centres for Urgent Care

This is the author accepted manuscript. The final version is available from IEEE via the DOI in this recordRight Hospital – Right Time (RH-RT) is the conceptualization of the use of descriptive, predictive and prescriptive analytics with real-time data from Accident & Emergency (A&E)/Emergency Departments (ED) and centers for urgent care; its objective is to derive maximum value from wait time data by using data analytics techniques, and making them available to both patients and healthcare organizations. The paper presents an architecture for the implementation of RH-RT that is specific to the authors’ current work on a digital platform (NHSquicker) that makes available live waiting time from multiple centers of urgent care (e.g., A&E/ED, Minor Injury Units) in Devon and Cornwall. The focus of the paper is on the development of a Hybrid Systems Model (HSM) comprising of healthcare business intelligence, forecasting techniques and computer simulation. The contribution of the work is the conceptual RH-RT framework and its implementation architecture that relies on near real-time data from NHSquicker.Torbay Medical Research FundEconomic and Social Research Council (ESRC)Torbay Medical Research FundAcademic Health Science Networ

Human agency in disaster planning: a systems approach

This is the final version of the article. Available from Wiley via the DOI in this record.Current approaches to risk management place insufficient emphasis on the system knowledge available to the assessor, particularly in respect of the dynamic behaviour of the system under threat, the role of human agents and the knowledge availability to those agents. In this paper, we address the second of these issues. We are concerned with a class of systems containing human agents playing a variety of roles as significant system elements - as decision makers, cognitive agents or implementers. i.e. Human Activity Systems (Checkland, 1999). Within this family of HASs we focus upon safety and mission critical systems, referring to this sub-class as critical human activity systems or CHASs. Identification of the role and contribution of these human elements to a system is a nontrivial problem whether in an engineering context, or, as is the case here, in a wider social and public context. Frequently they are treated as standing apart from the system in design or policy terms. Regardless of the process of policy definition followed, analysis of the risk and threats to such a CHAS requires a holistic approach, since the effect of undesirable, uninformed or erroneous actions on the part of the human elements is both potentially significant to the system output and inextricably bound together with the non-human elements of the system. We present a procedure for identifying the potential threats and risks emerging from the role(s) and activity of those human agents, using the 2014 flooding in SW England and the Thames Valley as a contemporary example.The project was partially supported the EU-CIRCLE (A pan-European framework for strengthening critical infrastructure resilience) project, funded by the European Union’s Horizon 2020 research and innovation programme (Grant Agreement No 653824)

Investigating the use of real-time data in nudging patients' Emergency Department (ED) attendance behaviour

This is the author accepted manuscript. The final version is available from the Society for Modeling and Simulation International via the URL in this record.Decision-making in healthcare is a complex process involving multiple stakeholders. One such stakeholder category is the intended users of the system itself – the patients. We present a study in which users use real-time hospital operations data to make attendance choices. The work was carried out with the Torbay & South Devon NHS Foundation Trust (TSDFT) and its network of Minor Injury Units (MIUs) and one Emergency Department (ED). The aim of this research was to provide information transparency on ED/MIU waiting times which would allow recipients, including, significantly, patients who are in need of urgent medical attention, to make informed decisions as to the facility that could best serve their needs. This work will contribute towards reducing pressure in ED by redistributing demand for minor ailments among the MIUs, since the MIUs have facilities for the treatment of minor injuries and the ED exists mainly for emergency and life-threating conditions.We would like to acknowledge the ESRC Impact Acceleration Account on Project Co-creation for the project on “Systems Modelling and Computer Simulation of Urgent and Emergency Care in Torbay & South Devon"

Testing AutoTrace: A Machine-learning Approach to Automated Tongue Contour Data Extraction

The Programme and Abstract booklet can be viewed at: http://www.qmu.ac.uk/casl/conf/ultrafest_2013/docs/Ultrafest%20abstract%20booklet.pdfOral Presentationpublished_or_final_versio

An Approximate Dynamic Programming Approach to Urban Freight Distribution with Batch Arrivals

We study an extension of the delivery dispatching problem (DDP) with time windows, applied on LTL orders arriving at an urban consolidation center. Order properties (e.g., destination, size, dispatch window) may be highly varying, and directly distributing an incoming order batch may yield high costs. Instead, the hub operator may wait to consolidate with future arrivals. A consolidation policy is required to decide which orders to ship and which orders to hold. We model the dispatching problem as a Markov decision problem. Dynamic Programming (DP) is applied to solve toy-sized instances to optimality. For larger instances, we propose an Approximate Dynamic Programming (ADP) approach. Through numerical experiments, we show that ADP closely approximates the optimal values for small instances, and outperforms two myopic benchmark policies for larger instances. We contribute to literature by (i) formulating a DDP with dispatch windows and (ii) proposing an approach to solve this DDP

Pragmatic evaluation of methods for retrieving unpublished information on comparator interventions in a systematic review of smoking cessation trials

OBJECTIVE: Reporting of the content and delivery characteristics of comparator interventions in published articles is often incomplete. This study examines the feasibility and validity of two methods for collecting additional information on comparator interventions from trial authors. METHODS & MEASURES: In a systematic review of smoking cessation trials (IC-Smoke), all trial authors were asked to send unpublished comparator intervention materials and complete a specially-developed comparator intervention checklist. All published and additionally obtained information from authors were coded for behaviour change techniques (BCTs) and other characteristics (type of comparator, provider, provider training, delivery mode and treatment duration). To assess representativeness, we assessed the amount of additional information obtained from trial authors compared with the amount that was published. We examined known-group and convergent validity of comparator intervention data when using only published or also unpublished information. RESULTS: Additional information were obtained from 91/136 (67%) of trial authors. Representativeness, known-group and convergent validity improved substantially based on the data collected by means of the comparator intervention checklist, but not by requesting authors to send any existing comparator materials. CONCLUSIONS: Requesting authors for unpublished comparator intervention data, using specially-developed checklists and unpublished materials, substantially improves the quality of data available for systematic reviews

Estradiol and testosterone levels in patients undergoing partial hepatectomy - A possible signal for hepatic regeneration?

In five adult male patients undergoing a 40-60% partial hepatectomy, serum sex hormone levels before and after hepatic resection were determined. Blood was drawn immediately prior to each surgical procedure and at specified time points postoperatively. Compared to hormone levels found prior to surgery, following major hepatic resection, estradiol levels increase at 24 and 48 hr, while testosterone levels decline, being significantly reduced at 96 and 144 hr. These data demonstrate that adult males who undergo a 40-60% partial hepatectomy experience alterations in their sex hormone levels similar to those observed in male rats following a 70% hepatectomy. These changes in sex hormone levels have been associated in animals with an alteration of the sex hormone receptor status of the liver that is thought to participate in the initiation of the regenerative response. These studies suggest, but do not prove, that in man, as in the case of the rat, sex hormones may participate in the initiation of or at least modulate in part the regenerative response that occurs following a major hepatic resection. © 1989 Plenum Publishing Corporation