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Notes 8 Guideline Execution Models and Systems. Major efforts to produce guideline execution schemes. Arden Syntax/Medical Logic Modules – MLMs Structure Simple “triggers” History Derived from HELP Strength Simplicity Use
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Major efforts to produce guideline execution schemes • Arden Syntax/Medical Logic Modules – MLMs • Structure • Simple “triggers” • History • Derived from HELP • Strength • Simplicity • Use • Widespread in hospital and drug information systems for warnings and monitors • Problems • The “Curly bracket problem”
Protégé/Eon • Structure • A general knowledge acquisition system based on a frame based ontology (Protégé) • An execution model for a specific model of guidelines which can be expressed in Protégé (EON) • ‘Standard’ reasoning mode: “Skeletal plan refinement” • History • Derived from Oncocin via Opal (Stanford) • Problems • Little re-use of ontologies – “curly bracket” variant • No standard reasoner • Steep learning curve to integrate pieces before you can start • Strengths • Flexibility • Ease of use of ontology driven knowledge acquisition • Many “Plug ins” – large community • Use • An international user community for expressing complex protocols • AIDS treatment (THelper) • Becoming a de facto standard for knowledge acquisition and interchange • Web site: www.smi.stanford.org
Pro Forma/Tallis Publets • Structure (Publets) • Integrated reasoning strategy and hierarchical decomposition of tasks • “Argumentation” • Web based architecture • History • Derived from work on “argumentation” and safety critical systems (RED), and “Oxford System of Medicine” (ICRF ACL John Fox) • Strengths • Unified view; Built in structure; Web orientation; User interface • Weaknesses • Lack of ontology, link to medical records • Dependence on a single mode of reasoning • Use • Commercial version available from InferMed • Open Web version just released • Goal of creating an open process in formal guideline development • Collaborative project with BMJ Evidence • Web site: www.openclinical.org/tallis
ASBRU • History • Out of Stanford but now Ben Gurion and Vienna • Structure • Integrated structure aimed at definitive solution • A language plus an execution model • Emphasises “Abstraction” • Strengths • Ambition, completeness, rigour • Weaknesses • Complexity, lack of good implementations (yet)| • Use • Largely limited to a few users • Highly influential on standards community • Web site:
Tallis - Plan with 4 Operations Plan Decision Action Enquiry
The Tasks • Plans • Gather operations together into hierarchical units • Operations • Enquiry • Define variables and questions to ask(Can also be linked to procedures, e.g. to enquire of EHR) • Decision • Weigh up evidence for and against • Or confirming or excluding • Set threshold for success • Support level if no confirmers or exluders • What happens if both? • (I don’t know – can you find out?)
The components (2) • Actions • Do something • In simple cases make a recommendation
The model • Things happened when triggered • Subject to sequencing constraints • Represented by arrows in flow diagram • Can have several ‘threads’ at once
Other Tallis Vocabulary • “Source” • A source of information, normally a variable • “Argument” • A way of using sources in a decision • “Candidates” the options for a decision • “Parameters” • Tasks can be “parameterised” by variables, but we will ignore this for now.
The expression editor • Invoked by clicking ‘…’ • Works by ‘highlight and replace • Really an assisted text editor • But if you use it you can’t make spelling mistakes • Follow demonstration in tutorial
The Execution Model • Create/Edit a Publet • Check it with the checker • Submit it for execution to a web engine someplace
Top Down Development“Keystones” • Keystones • Mutable elements that can stand in for something you haven’t decided how to do yet • Get basic shape, sequence, preconditions in place • Then decide if it can be a simple task or requires a plan • Keystones can be executed.
Your task for Friday and next week • Work through the tutorial on your own • Bring in a simple protocol but with more than one level on paper • Build a simple two-level protocol and test it. • Build the same protocol both bottom up and top down • Keep a Log of queries/problems for the Tallis group • Good software development practice • ‘Payment’ for use of software and training
Protégé • Main differences • Definable frames • Tallis are fixed • Information stored in frame structure • Tallis assumes information will come from elsewhere • Defined ad hoc • Plug and Play • Widgets • Tabs • Examples • Graphics • Pro-forma like graphical formalism • Or usable for other graphical presentations • UMLS • … • No Execution Engine / Pluggable execution engine • A knowledge acquisition tool • Requires separate execution engine for each application