Dealing with with Map Map Shock Shock Dealing Managing - - PDF document
Dealing with with Map Map Shock Shock Dealing Managing Complexity in Managing Complexity in Requirements Modelling Modelling Requirements Daniel Moody Daniel Moody Department of Department of Information Systems
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Department of Department of Information Systems Information Systems University of University of Twente Twente
Ar = requirements model Te = any requirements modelling technique Au = analysts and notation designers
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modelled
presents an intellectual challenge that has no precedent in human history
most RE notations
are not technical experts
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Amount of information that can be effectively conveyed by a single diagram limited by human perceptual and cognitive abilities:
Perception: ability to discriminate between
diagram elements reduces with their number and proximity (≈ 20 elements on A4 paper)
Cognition: number of diagram elements that
can be comprehended at a time limited by working memory capacity (≈ 7 ± 2 elements)
Solve problem for particular modelling technique (ER modelling) and generalise
Field Testing (Action Research) Initial Method Method refinement Laboratory Experiment 1: End User Understanding (O ) Laboratory Experiment 2: Documentation and Maintenance (O ) Field Experiment: Adoption in Practice Revised Method
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8 action research studies
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Problem-Specific Learning General Learning
Single Loop Learning (HOW)
Method Outcomes Objectives Principles
Triple Loop Learning (WHY) Double Loop Learning (WHAT)
Solve problem for particular modelling technique and generalise
Graphic Complexity Identification Contextualisation Navigational Map Indexing Signposting Redundancy Summarisation Decomposition Complexity Management Perceptual Grouping Spatial Contiguity
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Divide large diagrams into cognitively and perceptually manageable chunks
Sub-Diagram 1 Sub-Diagram n Sub-Diagram 2 Sub-Diagram 1
Single interconnected diagram Set of manageable sized sub-diagrams
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Customer Person Organisation Order Product Supplier Order Item Sales Region
located in
Warehouse Product Stock
consists of relates to
Employee Invoice Item Invoice
relates to consists of placed by
Customer Address
delivery address takes responsible for
Credit Terms
has has
Customer Contract Product Availability Purchase Item Purchase Order
placed by sent to from has is part of has contained in
Payment Apportion ment
made by results in matched to
Payment Product Price
manages
Customer Segment Contract Item
has consists of applies to belongs to has
Customer Contact No
has has
7 ± 2 elements per diagram
“Big picture” view: provides
information from different diagrams can be integrated
Summary Diagram Detailed Diagrams
summarise (possibly recursively)
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Allow multiple diagrams to appear simultaneously within the visual field
Use Gestalt principles to group elements together into manageable sized chunks
Both an alternative to and complementary to
decomposition
Unstructured Diagram Diagram organised into perceptual groups
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Quality features: understandability completeness, accuracy Contribution: definition of 9 principles for incorporating complexity management into diagrams and/or notations How will this improve practice/research:
end users
management into RE notations Main problems: needs to be tested on other types of models Scaling up: based on a real world solution
Requirements models an instance
called node-link diagrams:
Used in a wide range of
disciplines: business, education, communications, engineering, psychology Potential applications of the research beyond the IS field
ER models Requirements models Node-link diagrams