Full title

The role of style in designing dependable interactive systems

Keywords

ubiquitous systems, mobility, interactive systems, XML.

Summary

Ubiquitous computing requires a multitude of devices to have access to the same services. Abstract specifications of user interfaces are designed to separate the definition of a user interface from that of the underlying service.

The increasing availability of personalized and ubiquitous technologies leads to the possibility that whatever the device-to-hand is, it becomes the way to access services and systems. Therefore, interfaces to services must be designed for a variety of different types of device from desktop systems to handheld or otherwise portable devices. Different styles of interaction often suit different devices most effectively. While the appearance of ubiquitous devices has brought forth a proliferation of innovative interactive techniques, the broad categories and aspects of style as, for example, identified by Newman and Lamming [2] can still be applied. While a key-modal interface may be appropriate for a mobile telephone, with its limited screen and restricted keypad, a direct manipulation (DM) interface may be appropriate for a device based around touch / pen interactive techniques, such as current models of palmtop or tablet PCs.

Steve Gilroy, as part of his DIRC funded doctoral thesis, has proposed the incorporation of interaction style (as defined in introductory HCI texts such as [2]) into this type of specification [1]. By selecting an appropriate interaction style, an interface can be better matched to the device being used. Specifications that are based upon three different styles have been developed, together with a prototype Style-Based Interaction System (UbiSIS) that utilises these specifications to provide concrete user interfaces for a device. An example weather query service as well as a banking system have been described, including specifications of user interfaces for these services that use the three different styles and the concrete user interfaces that the specifications produce.

	<style type="form" location="http://www.inspiraldreams.com/SIS/weather">
	  <field name="cityText" type="text"/>
          <field name="postalText" type="text"/>
          <output_display name="weatherOut" type="text">
            <display_input type="weather">weatherData</input>
            <converter source="type" name="weatherText">getWeatherText</converter>
            <item>
              <input>weatherData</input>
              <output>weatherText</output>
            </item>
          </output_display>
          <form_fragment name="cityForm">
            <task>GetCityWeather</task>
            <input_field requirement="mandatory">cityText</input_field>
          </form_fragment>
            …
          <form name="WeatherQueryForm>
	    <form_display name="weatherDisplay" out="weatherOut">
            <action_set>
              <action_set name="Get Weather">
                <action name="Get Weather for City">
                  <fragment>cityForm</fragment>
                  <display>weatherDisplay</display>
                </action>
                <action name="Get Weather for Postal Code">
		  …
		</action>
              </action_set>
              <action name="Update Weather">
                …
              </action>
            </action_set;
          </form>
        </style>
	

Weather query form-fill interface specification

Typically in such situations a different low-level interface would have to be designed separately for each device. Style-specific design considerations normally take the form of guidelines, heuristics or ad-hoc rationalizations by designers [3]. Designs to support many devices may be facilitated by incorporating interaction style explicitly into an implementation. It is possible that several interaction styles may have to be supported for different users or parts of the system on the same device. As new technologies evolve to meet the demands of ubiquitous computing additional styles will emerge.

Weather query form-fill interface presentation

This work demonstrates that incorporating style-level descriptions into a model of a user interface can give more flexibility than forcing a single user interface model on a heterogeneous selection of devices. Interaction with a service is bound to the features of the platform through a mediating style description. The aim is to support an interface that is appropriate given the technological constraints or opportunities afforded by the platform.

Selected references

1. Gilroy, S.W. & Harrison, M.D. (2005) Using Interaction Style to Match the Ubiquitous User Interface to the Device-to-Hand. In Bastide, Palanque and Jörg (eds) Engineering Human Computer Interaction and Interactive Systems (Joint Working Conferences EHCI-DSVIS 2004, Hamburg, Germany, July 11-13), Springer Lecture Notes in Computer Science Vol. 3425 pp. 325-345.

2. Newman, W., Lamming, M: Interactive System Design. Addison-Wesley (1995) 293—322

3. Shneiderman, B: Designing the User Interface, 3rd edition. Addison Wesley Longman (1998) 71-74

Links

Papers

Gilroy, S.W. & Harrison, M.D. (2005) Using Interaction Style to Match the Ubiquitous User Interface to the Device-to-Hand. In Bastide, Palanque and Jörg (eds) Engineering Human Computer Interaction and Interactive Systems (Joint Working Conferences EHCI-DSVIS 2004, Hamburg, Germany, July 11-13), Springer Lecture Notes in Computer Science Vol. 3425 pp. 325-345.

Author

Steve Gilroy and Michael Harrison (Newcastle)