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Modelling patient flow in health care systems is vital in understanding the system activity and may therefore prove to be useful in improving their functionality. An extensively used measure is the average length of stay which, although easy to calculate and quantify, is not considered appropriate when the distribution is very long-tailed. In fact, simple(More)
Computer simulation of patient flow has been used extensively to assess the impacts of changes in the management of surgical care. However, little research is available on the utility of existing modeling techniques. The purpose of this paper is to examine the capacity of Statecharts, a system of graphical specification, for constructing a discrete-event(More)
INTRODUCTION Pulmonary metastasectomy for colorectal cancer is a commonly performed and well-established practice of ∼50 years standing. However, there have been no controlled studies, randomised or otherwise. We sought to investigate the evidence base that has been used in establishing its status as a standard of care. METHODS Among 51 papers used in a(More)
Computer simulation has been employed to evaluate proposed changes in the delivery of health care. However, little is known about the utility of simulation approaches for analysis of changes in the delivery of surgical care. We searched eight bibliographic databases for this comprehensive review of the literature published over the past five decades, and(More)
We present the findings of a discrete event simulation study of the hospital pharmacy outpatient dispensing systems at two London hospitals. Having created a model and established its face validity, we tested scenarios to estimate the likely impact of changes in prescription workload, staffing levels and skill-mix, and utilisation of the dispensaries'(More)
BACKGROUND Liver resection for metastatic colorectal cancer became established without randomized trials. Proponents of surgical resection point out 5-year survival approaching 50% whilst critics question how much of the apparent effect is due to patient selection. METHOD A 2006 systematic review of reported outcomes provided the starting point for(More)
The expectation maximisation (EM) algorithm is an iterative maximum likelihood procedure often used for estimating the parameters of a mixture model. Theoretically, increases in the likelihood function are guaranteed as the algorithm iteratively improves upon previously derived parameter estimates. The algorithm is considered to converge when all parameter(More)
BACKGROUND In the United Kingdom, clinical guidelines recommend that services for depression and anxiety should be structured around a stepped care model, where patients receive treatment at different 'steps,' with the intensity of treatment (i.e., the amount and type) increasing at each step if they fail to benefit at previous steps. There are very limited(More)
Existing approaches to conceptual modelling (CM) in discrete-event simulation (DES) do not formally support the participation of a group of stakeholders. Simulation in healthcare can benefit from stakeholder participation as it makes possible to share multiple views and tacit knowledge from different parts of the system. We put forward a framework tailored(More)