A glass Box Approach to Adaptive Hypermedia

Preface

After seeing some of the systems presented at the IWIUI conference, we saw that the time was ripe to introduce some usability demands on the intelligent interface systems and move them from their laboratory settings, solving toy-world examples. We also saw a lack of empirical evaluation of the usefulness of adaptive systems. We decided that we wanted to build an intelligent help system for a real-world, industrial, problem. We wanted to end the project with a comparative study were we would study how much the intelligent, adaptive parts of the system were contributing with in solving the help problem. We wanted the system to have a rich interface, both graphics and text. In January 1993 we did not know that the WWW-revolution was about to take place, so when imagining the interface to the help system, we did not picture an adaptive hypermedia system with a WWW-interface, which is what we ended up with three years later.

Some of the issues and ideas that came up during the car trip through the Everglades and during the following discussions back in Sweden with Prof. Carl-Gustaf Jansson and Rolf Leidhammar at the former Ellemtel Utvecklings AB, were interesting enough to cause NUTEK and Ellemtel to, together with SICS, put up the necessary funding for the project. The problems we set out to investigate lead to the research results presented in this thesis.

Of course, the ideas we put into the PUSH project had their roots in the experiences and results that members of the project brought with them rather than invented in the car in the Everglades. I brought experiences mainly from the Prometheus project where I together with Annika Wærn, Carl Brown, Per Lindevall and Jussi Karlgren, designed and implemented a route guidance prototype. The route guidance system presented the routes differently depending upon the role and expertise of the driver (commuters, taxi drivers, and tourists would get different route descriptions). Carl-Gustaf Jansson brought his interest in utilising artificial intelligent in interfaces. Annika Wærn brought her plan inference ideas and experiences from the Prometheus project. Jussi Karlgren brought ideas for natural language interfaces to information retrieval tools. Nils Dahlbäck brought both his expertise in empirically-based natural language interface design and his general competence in cognitive psychology.

During the years of the PUSH project, other researchers and students joined the project, each contributed ideas and helped in keeping the discussion from the car in the Everglades alive. Benoit Lemaire came with fresh ideas from his post-doc period with Johanna Moore. He convincingly showed us, both in discussions and through practical implementation that we should not try to imitate human-human communication but rather ”use computer for what computers are good at”. Catriona McDermid and Anna-Lena Ereback contributed expertise in how to perform the initial interviews with the targeted user group at Ellemtel. Klas Karlgren added ideas of how people learnt the domain we studied. Towards the end of the project, Åsa Rudström came with interesting ideas for machine learning. Malin Bladh, Fredrik Espinoza, and Marie Sjölinder who completed their Master’s theses within the PUSH project, each put in many working hours and were unusually good at making their voices heard in the discussions, thereby adding many valuable ideas. At the former Ellemtel, Måns Engstedt and the other developers of SDP contributed their expertise. STEFAN Zemke??

Now, at the end of the PUSH project, I can see that tackling a real-world problem is both rewarding but also more demanding than I expected. There were many bumps in the road and unexpected challenges, but I am proud to see that we managed to reach the two goals outlined when we started the project: to implement an adaptive help system for a real-world industrial domain, and to evaluated the adaptive parts of the system in a comparative study (even if neither the system nor the study looks like what I expected).

Acknowledgement

I am deeply indebted to all the members of the PUSH project mentioned above, without whom the PUSH project would not have generated the results I needed to complete this thesis. For helping me in writing this thesis, which is based on the results of the PUSH project, there are some people that I especially would like to thank.

First of all, I am deeply indebted to my supervisor at the department of Computer and Systems Sciences, Carl-Gustaf Jansson. Without his never-ending enthusiasm and faith in me I would never even have started to write this thesis, even less finished it.

I would also like to thank my ”extra” supervisor, Nils Dahlbäck. He has through friendly but hard criticism turned all fuzzy thoughts into clearer ideas - any fuzziness left is all my fault for not listening properly! Besides patiently reading and re-reading my thesis drafts he has also contributed many of the ideas presented. In particular, he worked together with me and Marie Sjölinder on the study of cognitive abilities and their relation to efficient usage of hypermedia.

Annika Wærn has through the years not only become the person with whom I worked most, but also a dear friend. Most of the important ideas in this thesis have come from her or in discussions with her. Annika’s sharp intellect has always amazed me and I am grateful for being allowed to work with her! Before leaving us and going to New York, Jussi Karlgren was the other person at SICS with whom I could talk about ideas. Jussi has an enormous capacity for generating ideas, and he quickly understands anything I try to say. Without Annika and Jussi it would not have been possible nor particularly good fun to work so hard with the PUSH project and with my thesis writing. Thank you both! Thanks also to Annika for reading this whole thesis in detail and providing so many insightful and useful comments!

I am also grateful to Åsa Rudström who read and commented my thesis, and to Torkel Franzén for reading and commenting on my horribly bad English. Also thanks to Fredrik Espinoza for the screendumps from the POP system.

At one point, I desperately needed funding in order to complete my thesis writing. I am grateful to Klas Barklöf at NUTEK for providing it.

I am grateful to Nomos Management AB for lending us their usability laboratory for the last study in the PUSH project. In particular I want to thank Dr. Robbin Battison and Richard Whitehand at Nomos.

I would also like to thank all the anonymous subjects from Ellemtel Utvecklings AB that participated in the studies despite their heavy workload at Ellemtel during this time period.

Thanks to the present and former members of the HUMLE group at SICS for providing a stimulating environment, and to Marianne Rosenqvist for being such a nice cookie general.

Thanks also to my parents Evy and Gunnar Höök, parents-in-law Hillevi and Jan-Christer Janson, and friends, especially Anna-Lena Johansson, for being a support to me and my family during this period.

Finally, three persons have had a rough time during my thesis writing, my husband Sverker and my children, Adam and Axel. Thank you Sverker for giving me the time, support, encouragement and love that I badly needed during this period. My lovely, beautiful children, Adam and Axel: thanks for providing all the useful distractions and for reminding me of what makes life worth living!

Kristina Höök

Upplands Väsby, August 1996

Preface and Acknowledgement i

Contents v

A Glass Box Approach to Adaptive Hypermedia 4

Introduction 1

Research Challenges for Adaptive Systems 2

Contributions of This Thesis 4

What This Thesis is Not About 7

Publications and Co-operation 7

Guide to The Thesis 9

A Framework for Adaptive Systems 13

What are Adaptive Systems? 14

Architecture of Adaptive Systems 15

Defining User Models 16

Classifying User Models 25

User Model Acquisition and Representation 26

Control Over the Adaptations 29

When to Adapt 30

Summary of Dimensions of Adaptive Systems 30

Adaptive Hypermedia 32

Content Adaptivity 34

Navigation Adaptivity 34

Examples of Adaptive Hypermedia Systems 35

Classifying POP 37

POP’s User Model 37

POP Is an Adaptive Hypermedia System 39

Knowledge Acquisition 41

Target Domain and Project 42

The Target Domain: SDP 42

The PUSH Project 45

Methods for Analysing Users’ Needs 46

Initial Interviews With Users of SDP 51

Method 51

Using SDP 52

Available Help Sources 52

Summary 53

Task Analysis and Corpus of Questions 53

Method 53

Results 55

Task Analysis 55

The User’s Background Knowledge 57

Users’ Roles 59

Graphic Lovers / Graphic Haters 60

Formulation of Queries 60

Users’ Questions 60

Answers 63

Questions not Gathered 64

Summary of Design Demands 64

Individual Differences and Navigation in Hypermedia 65

Method 67

Results 69

Patterns of Cognitive Abilities 69

Cognitive Ability and Task Completion Time 71

Correlation with Map-Reading Ability 72

Confidence and Efficiency 73

Discussion 75

Implications for Interface Design 75

Learning SDP Concepts and Principles 77

Method 78

Results 78

Conclusions for Design 78

Summary of the Knowledge Acquisition Phase 79

Design 81

Example Scenario 81

Non-Adaptive Scenario 81

Adaptive Scenario 85

Design Basis 86

Intelligent Tutoring Systems 87

Plan Inference (in Natural Language Systems) 90

Explanation Generation 92

Our Viewpoint: The Glass Box Model 95

Basing the Adaptivity on Users’ Tasks 100

Why Adaptive to Task? What Not to Adapt to? 100

Making Explanations Fitted to the Task 105

The Set of Information Entities 108

The Authoring Problem 112

How To Identify the User’s Task? 114

Textuality Principles 116

Where is the Glass Box? 119

What Is Unique? 120

Implementation 123

The Interface 123

An Interactive WWW Interface 123

Multimodal Input and Output 133

Summary of Interface Design 134

System Architecture 135

Knowledge Representation 136

Explanation Operators 139

Plan Recognition 139

Page Generator 140

Strengths of the Implementation 141

Bootstrapping and Evaluation 143

Evaluation of Adaptive Systems 143

Bootstrapping the Adaptivity 144

Paper and Pencil Exercise 145

Interface Evaluation and Bootstrapping of Adaptivity 146

Method and Subjects 146

Evaluation of the Interface 147

The Relevance Rules 147

Comparative Study of Adaptivity 148

Method and Subjects 148

Results 149

Navigation 150

Quality of Answers 151

User Satisfaction 152

Time Spent 154

Summary of the Comparative Study 155

Discussion 156

Concluding Remarks 157

The Problems Revisited 158

Active but Not Magical 158

Continuous Improvisation 159

Scale up 159

Imitating Human-Human Communication 160

Future Work 160

Future Work on POP 160

Figure V. A new architecture for POP.Future Work on Adaptive Hypermedia 161

Bibliography 163

Directory: ~kia -> papers
~kia -> Usability and fun An overview of relevant research in the hci community
papers -> Comparing Two Approaches to Context: Realism and Constructivism
~kia -> B. Cahour (1), P. Salembier (1), Ch. Brassac (2), J. L. Bouraoui (1), B. Pachoud (3), P. Vermersch

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