Petri Nets

EHR Design: Default Values as a Cause of Errors

by Jerome Carter on September 22, 2014 · 6 comments

When designing software, a lot of care is given to squashing bugs. But what does one do when the design itself is the problem?  Spotlight on Electronic Health Record Errors: Errors Related to the Use of Default Values, an article published by the Pennsylvania Patient Safety Authority, sheds much needed light on this subject.  As […]


The YAWL platform is a very sophisticated collection of tools that supports not only graphical modeling, but also enterprise-level workflow management capability.  It offers a workflow engine, web services, and other features required for business process management.     The graphical modeling environment is the focus of this series of posts. The YAWL Editor is the tool […]


My enthusiasm for workflow patterns stems, to a significant extent, from the fact that they provide an extraordinary library of process information.   By providing a pattern library, van der Aalst et al. have made available a set of modeling hints that are detailed and very helpful to workflow analysts.   Having them, one need not start […]


Over the last two years, I have written three series of posts that address workflow-related topics. The first, Preventing Your EHR from Working Against You, was a view of workflow issues from the standpoint of product selection and test script creation. Petri Nets and Clinical Information Systems, the second, focused on the basics of Petri […]


Clinical care consists of processes.  Examining patients, prescribing medications, mailing bills, reviewing charts–they are all processes.   Fortunately, there exists a perfectly good way of describing processes mathematically using graphs.  Graph theory originated when Leonhard Euler attempted to solve a simple problem mathematically.  The town of Konigsberg, where he lived, had four land areas that were […]


Control-flow patterns capture process information related to movement from task-to-task.  However, task execution does not tell the whole story of workflows.   Work usually consumes and produces information as well.  Well-designed systems anticipate information needs.     With this in mind, workflow modeling should include information flows as well as task execution sequences. In Workflow Data Patterns, Russell […]


Solving workflow problems requires an orderly approach to discovering details.  One can start by capturing a narrative description of the workflow to be analyzed.  Analyzing narratives for important verbs and nouns is a common technique for developing use cases (1). It works just as well for documenting workflows.  The great thing about starting with a […]