Hypermedia

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Hypermedia
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Hypermedia Development Fundamentals

• What is hypermedia/Multimedia
• Goals of hypermedia
• Hypermedia development practice

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Hypertext, Hypermedia MultimediaWhat are
the differences between them?

• Digital Multimedia is the field concerned with
  the computer-controlled integration of various
  forms of media, i.e.. text, graphics, still and
  moving images, animation, sounds and any other
  medium where information can be represented
  stored, transmitted and processed digitally.

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Multimedia has been described as

• Vaughan (1994) any combination of text,
  graphic art, sound, animation and video delivered
  to you by computer or other electronic means,
  thus non-interactive applications are included in
  the definition.
• Another definition however is Fetterman and Gupta
  (1993) multimedia is restricted to applications
  involving interactivity, colour and multisensory
  presentation, in other words is a participatory
  experience which takes place in an interactive
  computer environment.

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HCI concerns

• We can take it that multimedia can be either
  interactive or not but from the HCI point of view
  we are concerned with the problems encountered
  for the user while interacting with multiple
  channels of communication.
• Hypermedia applications may provide the user with
  further cognitive difficulties.

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Hypermedia an application which

• combines various forms of media
• contains nodes of information linked in a
  particular way (the prefix hyper refers to
  this)
• can adapt themselves to the users needs (often
  called intelligent)
• drastically changes the way documents or
  information look when presented to the user.

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Two definitions

• A technique for organising textual information in
  a complex, non-linear way... to facilitate rapid
  exploration or large bodies of knowledge.
• A set of nodes of information and a mechanism for
  moving among them.

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Structural Links

• Typically information is broken into blocks
  commonly called nodes, may contain text, video
  images.
• Nodes are inter-linked to create a structure to
  support navigation and browsing within the
  information space

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Other Links

• Associative
• Represents relationships, but can exist
  independently of one another
• Referential
• Related to associative links, but provides a link
  between an item of information and an elaboration
  or explanation. Link exists because of the
  existence of the other. (e.g. from a word - to a
  definition).

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Different information structures
Network
Hierarchical
Linear
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Hypermedia functions

• permits linking by association
• supports dynamic display
• allows the user to look at their chosen level of
  detail
• provides a flexible interface to facilitate
  different exploration techniques

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Weaknesses in Hypermedia systems

• Cognitive load... purpose may be to provide user
  with and educational experience but cognitive
  load posed by navigating among various items may
  be so great that the user has little energy left
  for absorbing the content.

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Lost in Hyperspace,why?

• Our ability to navigate further is impeded if we
  are not familiar with the structure and dont
  know where we are.
• User doesnt understand local context - new city
• If catching a cab from (a) to (b) wouldnt need
  to know local context, if driving we would.
• To navigate new regions in hyperspace effectively
  we need clues, maps or guides.
• Important to note that distance is indicated by
  time it takes to travel, or thickness of a book,
  no concept of this in hyperspace.

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• Navigation...users tend to make heavy use of
  spatial metaphors they report feeling lost
  speak of going up and down between levels or
  going in or out of situations.
• Spatial mental models...there is a lack of
  spatial mental models or mental maps in order
  to assist the easy movement from one context to
  another.

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HCI problems associated with Hypermedia

• Navigation and spatial disorientation
• Distraction from goal directives
• Complexity in the interface
• Universal design
• Different modalities of interaction

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Navigation and spatial disorientation(problems
and symptoms)

• Users get lost
• Users may find it difficult to gain an overview
  of the material on the system
• Finding specific information which they know is
  present.
• Learners often ramble in an unmotivated and
  instructionally inefficient fashion
• Getting to grips with the interface which
  controls the various facilities

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Distraction from goal directives

• Users can be distracted from goal directed
  activities by hypermedia stimulation
• Lack of cognitive control structures means task
  take longer
• Hypertext can require extensive decision-making
  skills on the part of users
• Using spatial awareness can help with the
  cognition of such systems.

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Effect of different tasks and users

• Users having different tasks to perform use
  hypermedia systems in different ways (different
  mechanisms are needed to support different tasks)
• Results support the view that the way in which
  tools are used in search and learning are highly
  task dependent
• Tools can be effectively used with no apparent
  cost in terms of interface complexity
• Performance on systems lacking such tools are
  likely to be degraded in a number of ways,
  notably in terms of efficiency in reaching new
  information.

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Current WWW issues

• Underlying ideas still being refined, debated and
  improved
• Two major limitations
• effective location of information (procurement)
• information (utilisation).
• Active annotation and restructuring of networks
  based on feedback

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Usability

• If Hypermedia applications lack quality
  classification of the contents then almost all
  other features are irrelevant and merely a
  distraction.
• Style is no substitute for substance,
  hypermedias value is in its usability

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Hypermedia Applications

• Need to understand the problems of hypermedia
  development so that we improve current practice.
• Largely on an ad hoc basis. Need encourage a more
  disciplined approach to deliver quality
  performance in complex systems
• What aspects need to be considered during the
  development process?