Notes 8 guideline execution models and systems
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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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Notes 8 guideline execution models and systems

Notes 8Guideline Execution Models and Systems

Major efforts to produce guideline execution schemes

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”

Prot g 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:

Pro forma tallis publets

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:



  • 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

Tallis - Plan with 4 Operations





The tasks

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

The components (2)

  • Actions

    • Do something

      • In simple cases make a recommendation

The model

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

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

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

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

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

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

Prot g


  • 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

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