I can’t quite believe I’m adding a glossary to my blog site, but given the subject matter, it may help people unfamiliar with some of content. Also, there are a number of instances where I apply very specific meaning to generic words.

Abstract user interface

An abstract user interface describes the information conveyed between user and computer independently of specific interaction modalities.

Accessibility layer

An accessibility layer is an Application Programming Interface (API) provided by some computer operating
systems/ user interfaces, and some programming languages to allow Assistive Technology to inspect,
and potentially modify, the content currently presented to the user.

Action Data Flow Diagrams (ADFDs)

An Action Data Flow Diagram is a notation within the Shlaer-Mellor method used to describe the behaviour of state actions in a state model.

Adaptable system

A system able to be configured using a priori knowledge before use.

Adaptive system

A system able to dynamically change in response to events.

Animated GIF

A bitmap format used typically for animating icons on a graphical user interface. The format allows for the definition of a sequence of bitmap images to be presented in sequence at the same graphical location over time.


In terms of my research research, an archetype is a generic pattern used to automatically generate a computer program from a Shlaer-Mellor analysis model.

Aspect Oriented Software Development (ASOD)

Aspect Oriented Software Development is a software design technique that aims to separate supporting functionality from the core behaviour of complex computer systems, describing subject matters independently and then synchronizing each “aspect” of that supporting functionality with the main body of
the program.

Assigner state model

An assigner state model is a state model that describes, and controls, the formation of associations between two ore more specified objects on a Shlaer-Mellor Information Model.

Assistive Technology (AT)

Assistive technology refers to computer hardware and software that provides specific affordances to disabled
users who are interacting with a computer user interface.

Augmented reality

The term augmented reality refers to the situation in a use interface where a computer modifies a user’s
perception of the physical space around her, adding, removing, or modifying elements in the apparent
physical world.


A bridge is a term in the Shlaer-Mellor method that describes the relationships between two problem domains. For example the concept of a menu of user selectable options in a user interface has counterparts to pop-up menus and drop-down menus used in graphical user interfaces to represent them. The detailed description of the relationship between the concept of a list, and those renderings of a list is called a bridge.

Cascading Style Sheet

Web mark-up languages such as HTML and XML, and some proprietary programming languages such as Adobe Flash, separate the the detailed specifics of content presentation from the underlying content, for example separating text content from the font details associated with it. Those specifics are described in Cascading Style Sheets. The word “cascading” refers to the polymorphic structure of the descriptions that allows for a single style sheet to be extended and adapted by others.

Computer Aided Software Engineering (CASE)

Computer Aided Software Engineering is a general term for computer programs that help automate the production of computer software. The term is most typically encountered in terms of tools that allow diagrammatic representations of requirements and design specifications, and in terms of tools thatautomatically generate computer programs from such diagrams.

Database transaction

In terms of my research, a database transaction refers to a series of actions applied to a database where that series has specific meaning in its own right.

Design space

A medium, physical or abstract, through which a user and device may interact.

Design space properties

The properties of information within a design space are characterized according to the degree of processing required by the human brain, that is automatic processing and controlled processing, Those properties related to automatic processing are considered direct properties related to perception. Those properties related to controlled processing are considered indirect properties related to cognition. In the visual design space, colour is considered as a
direct property, text as an indirect property.

Design space structure

Nesbitt characterizes raw information conveyed within the multi-sensory design space as nominal, quantitative, and ordered. Quantitative information is further sub-categorized as temporal, spatial, and geographical. Each category of information is considered to be a structure composed of a spatial substrate augmented with marks, properties, and
temporal encodings.

Directed graph

A directed graph is a mathematical concept used to describe the connectedness of things where the connectedness is not associative. For example a route to work is a directed graph because the order of locations visited on the way to work is in a defined order.

Domain Chart (DC)

A Domain Chart describes the client-server relationships of problem domains when using the Shlaer-Mellor object orientated analysis and design method.

Executable UML

Executable UML is a profile of the UML Model Driven Architecture based on the Shlaer-Mellor method of object oriented analysis and design. As such, it is a view of Shlaer-Mellor from a UML perspective.

Fibonacci numbers

Fibonacci numbers, or more accurately the Fibonacci series is an infinite series of numbers wher the next number in the series is the sum of the two previous numbers. The series starts with 0, 1.


Fidelity, in terms of my research, is an expression of how accurate a copy is to its source.

Finite state machine

A finite state machine describes the behaviour of a system in terms of discrete steps, defining the order in which those steps may occur and the rules governing the timing and choice of the next step.

Game theory

Game theory is a branch of applied mathematics that expresses strategic decision making in competitive environments.


The description of an unique shape describing a letter of an alphabet is a glyph.

Graph theory

Graph theory is a branch of mathematics that expresses the connectedness of things in an abstract sense. For example roads connect to each other at intersections, books in a library are arranged by subject and author, computer chips are connected by a multitude of wires.

Haptic design space

The haptic design space is the physical medium, related to human mobility, through which a user and device may interact. Nesbitt sub-divides this space into temperature, pain, tactile, chemogenic, kinaesthetic. Of these, only the tactile and kinaesthetic design spaces are considered practical and usable for the transmission of information.


A hapticon is a language independent indication from a computer to its user of information, typically status information, that is conveyed haptically. A mobile phone vibrating to indicate an incoming message or call is an example of a hapticon. Braille, on the other hand, is not a Hapticon as it conveys language information.


Hypermedia is an extension of the concept of Hypertext, and is a way of expressing multimedia content in a non-linear manner. With Hypermedia, both text and audio-visual content is described in nonlinear form, with the audio-visual content also potentially decomposed into fragments; a common example is video which may contain a mix of image sequences, audio clips, and closed captioning for hearing impaired users. What makes Hypermedia unique in concept compared to Hypertext is the implied sequencing necessary for audio-visual content.


Hypertext is a way of expressing textual content in a non-linear manner by fragmenting the text into fragments and then describing the relationships between the fragments. For example a book consists of chapters, and those chapters follow a specific order. Within each chapter, there may be headings, sub-headings, lists, and tables. The lists and tables in turn may have captions associated with them. This model of text is most commonly found in the structure of Web pages.

Hypertext Mark-up Language (HTML)

Hypertext Markup Language is the default mark-up language of Internet Web pages. It is a subset of the features generally ascribed to hypertext systems.

Information Model

A Shlaer-Mellor Information Model describes objects of an object oriented analysis graphically in terms of their attributes and their (sometimes temporal) relationships between each other.


In terms of my research, inheritance refers to the polymorphic properties of objects in object oriented programming and design.

Intelligent agent

In terms of my research, an intelligent agent is an autonomous computer program or algorithm working on behalf of some other “entity”. Typically that entity is the user of a user interface, but it may be another agent. An agent works to a set of rules that may change over time as the result of experience by the agent.

Interaction modality

An interaction modality describes the protocol that occurs between the user of a computer user interface, and and the program represented by that user interface.

Jackson Structured Programming (JSP)

Jackson Structure Programming is a programming design technique that decomposes problems functionally, and represents that decomposition in diagrammatic form.


Java is an object-oriented computer programming language heavily geared towards the production of
graphical user interfaces and Web applications in general.

Join point

A join point in Aspect Oriented Software Development describes a point of synchronization between
different aspects of a program and the main program.

Information Model

The Shlaer-Mellor Object Oriented Analysis andDesign Method describes systems in terms of the
relationships between terms of an ontology. The Information Model is a diagrammatic expression of
these relationships.

Interaction act

Interaction acts are “abstract units of user-service interaction that contain no information about modality or presentation. This means that they are independent of devices, services and interaction modality.” (Nylander, 2005).

Late binding

In terms of my research, late binding refers to the concept of matching interaction modalities, their metaphors, and associated rendering details to the abstract information conveyed by them as close to the time of rendering as possible. For example, a decision to use colour to indicate importance would preferably be made one one knows details of the user’s physical and cognitive capabilities, the device used to communication, and the environment in which the user and device are communicating.


[Design Spaces] A mark is an elementary entity capable of perception
within a spatial substrate. In the visual design space, this may be a point, a line, a circle etc.[Library systems] Mark is a technique used to classify published documents.


In terms of my research, a meta-model is a model of a language or an ontology. For example, an object oriented analysis model of object oriented semantics is a meta-model, as is an object oriented model of user profiling (as opposed to a model of a specific user’s profile).


A metaphor is an analogy of ideas. In terms of my research, the terms metaphor, metonymy, and
synecdoche are used interchangeably to mean the use of analogy in user interfaces to inform and
support user interaction.


In terms of my research, a method expresses a specific notation and process used in developing
computer software. In contrast methodology is the study of methods.
[Object oriented design] A method is algorithmic behaviour that may be instantiated on a particular class of information.


Mise-en-scene is a term from theatre and film production the refers to the entirety of the visual
elements of the image presented to the audience/viewer at any particular moment.


Computers and their users communicate through physical mediums. Each case of that communication
involves a protocol between computer and user that involves one or more physical mediums. A modality identifies a protocol operating on a given computer architecture. Keyboard input of text is a modality. Menu selection through right-click of a mouse button
on a WIMP interface is also a modality.

Model Driven Architecture (MDA)

A Model Driven Architecture describes a computer software architecture that is largely independent of the underlying computer hardware, providing a general abstract view of hardware.

Model-View-Controller (MVC)

Model-View-Controller is an approach to describing user interaction with a computer that separates that interaction into three abstractions. “Model” refers to the information passing between user and computer. “View” refers to how the Model is rendered to the user. “Controller” refers to the possible ways that Content may be navigated through the rendered View.

Moore state model

A Moore state model is a representation of a finite state machine in which behaviour is associated only with entry to the state, and not with the transition between states.

Multiple Sclerosis (MS)

Multiple Sclerosis (MS) is a progressive disease of the central nervous system caused by the build up of deposits of the outside of nerve tissue. This build-up causes the nerves to fail or misfire. The randomness of the deposits means that the effects felt by people with MS vary widely in symptoms and severity. Symptoms include blurred/double vision, a complete loss of touch (tactile and kinaesthetic), and limb tremors. These symptoms are progressive in severity, but are also intermittent; in the early stages of the disease it is quite possible to be able to walk in the
morning, but not in the afternoon and vice versa. The disease is terminal and there is currently no known cure.

Multi-sensory design space

The multi-sensory design space is an aggregate of all the physical design spaces
through which a user and a device may interact. Nesbitt defines this to be visual, sonic, and tactile.

Object Constraint Language (OCL)

OCL is the declarative language used by UML to describe rules and behaviour that cannot be
represented by UML diagrams.

Object Oriented Analysis and Design (OOA/OOD)

Object oriented analysis and design is a software engineering approach to describing complex problems in terms of related, and potentially, cooperating entities. For example a computer user interface may be described as a relationship between the content to present, the manner of its presentation, and associated interaction modalities between the interface and the user. Such descriptions are in two parts: a description of the system being described, and a reified implementation of that system.


In terms of my research, an ontology is the collection of concepts or ideas related to a particular subject matter.


A paraplegic is a person with severe motor and/or sensory impairment in their lower extremities. The term is typically used to refer to a person who requires permanent use of a wheel-chair for mobility.


A multi-sensory display of abstract information. For Nesbitt, Perceptualization is inferred to be a human quality.


A persona is a (typically) narrative description of a fictional user of a computer interface. It describes
the fictional person’s use of the computer in terms of their life, potentially including illustrative scenarios.

Polymorphic Task Decomposition (PTD)

Polymorphic Task Decomposition is a derivative of Task Analysis. In this case, as it decomposes a stimulus-response pair into smaller actions, it also describes alternative interaction modalities and the rationale for selecting them.


In terms of my research, polymorphism is the ability to generalize information content and/or dynamic behaviour associated with information content. For example there are many possible implementations that may render a list of content in a graphical user interface: a simple list, a drop-down list, a pop-up list, or a grid-based layout such as the user interface on the Apple iPhone.

Quality assurance

Quality assurance in my research, is the checking of the process by which a product is made and tested against a guide to best practice for that category of product. It is a largely qualitative process.

Quality control

Quality control in my research, is the checking of a product and/or its components against a test specification. It is a quantitative process.

Quantization error

Quantization errors occurs when approximations are made during measurement. In terms of this research, such quantization errors occur when analogue data is described digitally. The greater the range of values approximated to a single value by the steps in the digitization process, the greater the quantization error.

Real-time software

Real-time software is computer software that reacts to its environment in a timely fashion. That reaction may be to the actions of people, for example through a user interface, or in response to sensor information in system control applications.

Recursive design

Recursive design is a term used in the Shlaer-Mellor object oriented analysis and design method to describe the process of translating object oriented models of program specifications directly into computer programs by applying translation rules to a meta-model of object oriented analysis.


Reification is the process of making concrete that which is abstract. A photograph is a reification of time and place, with all of the lens distortion and selectivity implied. The fidelity of a reified concept may very widely.


In terms of my research, scanning is a term associated with Assistive Technology where user options are presented as a timed sequence of options, with the user making their choice as that option is presented in turn.

Screen reading

Screen reading is a term associated with Assistive Technology where a
computer user interface is described to a user audibly. Typically this takes the form of a synthetic human voice reading text and menu options.

Semantic decomposition

With semantic decomposition, a problem or system is decomposed into a tree of ontologies, where the higher the ontology in the tree, the closer it is semantically to the original problem or system description.

Soft key

A soft key is a (typically) mechanical button whose action depends upon context. Typically soft keys are found next to a screen on mobile phones, or on the edges of the phone.

Sonic design space

The sonic design space is the physical medium, related to human hearing,
through which a user and device may interact. Spatial substrate A spatial substrate describes the orientation of information expressed within a physical design space, describing that information using axes and a coordinate system of a precision appropriate to how a user perceives content within that design space.

Spiky profile

The term, spiky profile, refers to cases where a person, when described in terms of archetypes or stereotypes of disability, exhibits multiple impairments. Such perceived impairments are not necessarily independent of each other.

State transition table

A state transition table is a Shlaer-Mellor term for a complete tabular description of a finite state model that describes not only the intended state transition seen on a state transition diagram, but also exception conditions.

Structured Query Language (SQL)

SQL is an international standard for describing manipulation of a relational database in terms of human readable text.

Structured Analysis and Structured Design (SASD)

Structured analysis and structured design refers to software methods that functionally decomposes a computer systems problem into smaller and more manageable problems. It is an elaborative approach that first decomposes the given problem and then augments that decomposition with additional design detail until the computer program and hardware are fully specified.


Subtyping is closely related to the concept of inheritance. In this research, subtyping refers to the use of polymorphism in Shlaer-Mellor Information Models to describe variation in objects. In this case the inheritance hierarchy is considered to be disjoint complete, and that an object may migrate subtype whist retaining its identity.

Surround sound

Audio systems provides a 3D surround sound experience to users by positioning typically five or seven synchronized loud speakers around the user at specific distances and angles. The surround sound experience may also be approximated though digital manipulation of stereo signals for headphone use.


Tcl/Tk is an interpreted programming language often used for systems programming tasks, and which is strongly linked to the Tk graphics API.

Temporal encoding

A temporal encoding describes the position of one or more marks within a spatial substrate over time. In the visual design space this corresponds to the animation of a point or line on a display. As described by Nesbitt, temporal encoding occurs within a single substrate.

Traceability of design

Traceability of design refers to the principle that it should be possible to identify any any part of a design related to a particular design requirement, and vice versa. In terms of my research, it refers to the concept that it should be possible to identify the ranges of users supported by any component of a rendered user interface.


Transcoding is the direct digital-to-digital conversion of encoded data between data formats. In terms of my research, the term is used to refer to the direct conversion of protocols between interaction modalities.


In terms of my research, the term tree refers to the hierarchical organization of information.


When properties of elements in a user interface are changed between two settings progressively through interpolation of those settings over time, they are said to tween.

Unified Modelling Language (UML)

UML is a collection of diagram semantics aimed at supporting a wide range of object oriented methods. It is not a method in itself, it is only notation. Typically a method uses a subset of UML.

Universal accessibility

Universal access is generally taken to mean the right of all people to have access to goods and services. In terms of my research, universal accessibility refers to the concept of maximizing the usability of a user interface to support universal access.


A use-case describes the expected behaviour of a system in response to an external stimulus. “User places a call” is an example of a use-case on a mobile phone.

User Centred Design (UCD)

User Centred Design is a process of user interaction design the focuses on the end-users needs, wants, and abilities at each stage of the design process.

Virtual desktop

If the resolution of a user interface screen is higher than that displayable by the user’s physical screen, causing the user to navigate around the complete image, the interface is said to express a virtual desktop.

Virtual reality

Virtual reality is a term used to describe the situation which a user is immersed in an artificial world to the exclusion of the real world. The artificial world may be a simulation of the real world, or be deliberate fantasy.

Visual design Space

The visual design space is the physical medium, related to human sight, through which a user and device may interact.

WCAG (Web Content Accessibility Guidelines)

The guidelines of the Worldwide Web Consortium that describe established best practice in the construction of Web content to improve access to disabled users (see quality assurance).


WIMP is an acronym for “Window Icon Menu Pointing Device” and refers to a collection of interaction modalities typically associated with computer user interfaces.

Yourdon Structured Analysis and Design

Yourdon Structured Analysis and Design is a specific implementation of the ideas of Structured Analysis and Design that defines both a diagrammatic notation to describe decomposition, and the particular process to follow in constructing those diagrams.