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Chapter 7
Mind the Gap: Surviving the Dangers of User Interface Design

Martin Rantzer
Systems Engineering Lab, Ericsson Radio Systems, Linköping, Sweden
email: rantzer@acm.org

Table of Contents
Abstract
1.  Introduction
2.  Overview of the Delta Method
2.1  What is Special about Delta?
3.  The Case Study: TSS 2000
4.  Before Crossing the Gap
4.1.  System Definition
4.2.  User Profiling
4.3.  Task Analysis
4.4.  Design Preparations
4.5.  Usability Requirements
5.  Bridging the Gap
5.1.  Conceptual Design
5.1.1.  The Workshop
5.1.2.  Participants in the Workshop
5.1.3.  The Design Room
5.1.4.  Walk-Through of the Background Material
5.1.5.  User Environment Diagrams
5.1.6.  Conceptual Design in TSS 2000
5.1.7.  The Result
5.2.  User Interface Design
5.2.1.  Opening Screen Main Window
5.2.2.  Choosing a Metaphor
5.2.3.  Transforming the Conceptual Model into a User Interface Design
6.  After the Bridge
6.1.  Usability Tests
6.2.  Computer Prototype
7.  Conclusions
8.  Acknowledgments
9.  Background to the Delta Method
10.  References

ABSTRACT

The Delta Method is a systematic approach to usability engineering that is used within the Ericsson Corporation. The method has successfully supported usability work in a number of projects and continued to evolve during the process. We have managed to introduce usability engineering as a way to establish a solid platform of user data and to extend that platform to the other side of the design gap.

Based on a real-life case study we describe and exemplify the background information processes necessary to bridge the design gap. The central activities during the user interface design are two design workshops. During the first workshop we structure the services of the system into a conceptual model and during the second we transform the implementation independent structure into a paper prototype that reflects the future user interface.

The case study shows that a method such as Delta does not stifle the creativity that is needed to design good user interfaces. It helps to structure the work so that the combined force and creativity of a usability team can be used efficiently during the process.

1. INTRODUCTION

As usability engineering is making its way into the mainstream of software development at Ericsson, we face the problem of integrating usability activities with the design process and putting the results of the usability work to good use in the design of products. This difficult integration often becomes acute when we try to bridge the gap, transforming the user information into an effective user interface design. To bridge this gap we use a usability engineering method called Delta. In order to build an adequate bridge, the scope of the method spans from user and task analysis to conceptual modeling and to the design of user-interface prototypes.

The face of the telecommunications market is changing rapidly, and usability has become a very important factor in attracting new customers. Following the deregulation our traditional customers, the old, large, and skilled telephone administrations, are forced to change their operation to meet the competition from the new operators. They need powerful and flexible systems to support their experienced and skilled personnel in order to stay ahead of the competition. To continue to supply these customers with our products, our systems must evolve to support the new situation.

We also want to attract the new telecom operators who want to “turn the key on the new system and start earning money”. They want a system that is up and running within minutes after delivery, that keep on running with no down time, and that can be managed by unskilled personnel. In this case we have to provide most of the relevant processes rather than being able to adapt existing ones within an organization. The business processes and the general technical requirements are the same in both cases, but the new context poses dramatically different usability requirements on the user interface of the system.

The typical context for our usability engineering efforts is large, complex technical computer systems within the telecom industry. It is often a technical support system used to manage the installation, operation, and maintenance of large telecom networks. We have used the Delta Method during the development of new systems and redevelopment of existing ones. The methodology is sufficiently scaleable to be used in small projects and it is also applicable outside the telecom domain. It is more doubtful that it would support experimental prototyping as described by Smith in Chapter 11.

This chapter presents the Delta Method and how it was used in the design of the next generation of a test and simulation tool for telecom equipment. As always in case studies the context and conditions are unique, but we believe that many of the problems are universal and that our experience can be used to bridge the design gap easier.


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