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User Modeling and User-Adapted Interaction 20

Editors:Alfred Kobsa
Standard No:ISSN 0924-1868 (print) EISSN 1573-1391 (online)
Links:link.springer.com | Table of Contents
  1. UMUAI 2010-02 Volume 20 Issue 1
  2. UMUAI 2010-06 Volume 20 Issue 2
  3. UMUAI 2010-08 Volume 20 Issue 3
  4. UMUAI 2010-10 Volume 20 Issue 4
  5. UMUAI 2010-12 Volume 20 Issue 5

UMUAI 2010-02 Volume 20 Issue 1

PERSONAF: framework for personalised ontological reasoning in pervasive computing BIBAKFull-Text 1-40
  William T. Niu; Judy Kay
Pervasive computing creates possibilities for presenting highly personalised information about the people, places and things in a building. One of the challenges for such personalisation is the creation of the system that can support ontological reasoning for several key tasks: reasoning about location; personalisation of information about location at the right level of detail; and personalisation to match each person's conceptions of the building based on their own use of it and their relationship to other people in the building. From pragmatic perspectives, it should be inexpensive to create the ontology for each new building. It is also critical that users should be able to understand and control pervasive applications. We created the PERSONAF (personalised pervasive scrutable ontological framework) to address these challenges. PERSONAF is a new abstract framework for pervasive ontological reasoning. We report its evaluation at three levels. First, we assessed the power of the ontology for reasoning about noisy and uncertain location information, showing that PERSONAF can improve location modelling. Notably, the best ontological reasoner varies across users. Second, we demonstrate the use of the PERSONAF framework in Adaptive Locator, an application built upon it, using our low cost mechanisms for non-generic layers of the ontology. Finally, we report a user study, which evaluated the PERSONAF approach as seen by users in the Adaptive Locator. We assessed both the personalisation performance and the understandability of explanations of the system reasoning. Together, these three evaluations show that the PERSONAF approach supports building of low cost ontologies, that can achieve flexible ontological reasoning about smart buildings and the people in them, and that this can be used to build applications which give personalised information that can provide understandable explanations of the reasoning underlying the personalisation.
Keywords: Personal ontology; Ontological reasoning; Pervasive personalisation; Scrutable personalisation; Pervasive computing
A query expansion and user profile enrichment approach to improve the performance of recommender systems operating on a folksonomy BIBAKFull-Text 41-86
  Pasquale De Meo; Giovanni Quattrone
In this paper we propose a query expansion and user profile enrichment approach to improve the performance of recommender systems operating on a folksonomy, storing and classifying the tags used to label a set of available resources. Our approach builds and maintains a profile for each user. When he submits a query (consisting of a set of tags) on this folksonomy to retrieve a set of resources of his interest, it automatically finds further "authoritative" tags to enrich his query and proposes them to him. All "authoritative" tags considered interesting by the user are exploited to refine his query and, along with those tags directly specified by him, are stored in his profile in such a way to enrich it. The expansion of user queries and the enrichment of user profiles allow any content-based recommender system operating on the folksonomy to retrieve and suggest a high number of resources matching with user needs and desires. Moreover, enriched user profiles can guide any collaborative filtering recommender system to proactively discover and suggest to a user many resources relevant to him, even if he has not explicitly searched for them.
Keywords: Folksonomies; Query expansion; Recommender systems; Tag ranking; Social tagging; Personalised query answering
Exploring the feasibility of web form adaptation to users' cultural dimension scores BIBAKFull-Text 87-108
  Matías Recabarren; Miguel Nussbaum
With many daily tasks now performed on the Internet, productivity and efficiency in working with web pages have become transversal necessities for all users. Many of these tasks involve the inputting of user information, obligating the user to interact with a webform. Research has demonstrated that productivity depends largely on users' personal characteristics, implying that it will vary from user to user. The webform development process must therefore, include modeling of its intended users to ensure the interface design is appropriate. Taking all potential users into account is difficult, however, primarily because their identity is unknown, and some may be effectively excluded by the final design. Such discrimination can be avoided by incorporating rules that allow webforms to adapt automatically to the individual user's characteristics, the principal one being the person's culture. In this paper we report two studies that validate this option. We begin by determining the relationships between a user's cultural dimension scores and their behavior when faced with a webform. We then validate the notion that rules based on these relationships can be established for the automatic adaptation of a webform in order to reduce the time taken to complete it. We conclude that the automatic webform adaptation to the cultural dimensions of users improves their performance.
Keywords: User modeling; Human--computer interaction; Usability; User culture; Adaptive webform; Webform design; Hofstede's cultural dimensions

UMUAI 2010-06 Volume 20 Issue 2

Automatic detection of users' skill levels using high-frequency user interface events BIBAKFull-Text 109-146
  Arin Ghazarian; S. Majid Noorhosseini
Computer users have different levels of system skills. Moreover, each user has different levels of skill across different applications and even in different portions of the same application. Additionally, users' skill levels change dynamically as users gain more experience in a user interface. In order to adapt user interfaces to the different needs of user groups with different levels of skills, automatic methods of skill detection are required. In this paper, we present our experiments and methods, which are used to build automatic skill classifiers for desktop applications. Machine learning algorithms were used to build statistical predictive models of skill. Attribute values were extracted from high frequency user interface events, such as mouse motions and menu interactions, and were used as inputs to our models. We have built both task-independent and task-dependent classifiers with promising results.
Keywords: Expertise; Skill; User modeling; Machine learning; Graphical user interfaces; Intelligent user interfaces; Adaptive user interfaces; GOMS
Multimodal semi-automated affect detection from conversational cues, gross body language, and facial features BIBAKFull-Text 147-187
  Sidney K. D'Mello; Arthur Graesser
We developed and evaluated a multimodal affect detector that combines conversational cues, gross body language, and facial features. The multimodal affect detector uses feature-level fusion to combine the sensory channels and linear discriminant analyses to discriminate between naturally occurring experiences of boredom, engagement/flow, confusion, frustration, delight, and neutral. Training and validation data for the affect detector were collected in a study where 28 learners completed a 32-min. tutorial session with AutoTutor, an intelligent tutoring system with conversational dialogue. Classification results supported a channel × judgment type interaction, where the face was the most diagnostic channel for spontaneous affect judgments (i.e., at any time in the tutorial session), while conversational cues were superior for fixed judgments (i.e., every 20 s in the session). The analyses also indicated that the accuracy of the multichannel model (face, dialogue, and posture) was statistically higher than the best single-channel model for the fixed but not spontaneous affect expressions. However, multichannel models reduced the discrepancy (i.e., variance in the precision of the different emotions) of the discriminant models for both judgment types. The results also indicated that the combination of channels yielded superadditive effects for some affective states, but additive, redundant, and inhibitory effects for others. We explore the structure of the multimodal linear discriminant models and discuss the implications of some of our major findings.
Keywords: Multimodal affect detection; Conversational cues; Gross body language; Facial features; Superadditivity; AutoTutor; Affective computing; Human-computer interaction

UMUAI 2010-08 Volume 20 Issue 3

User-adaptive explanatory program visualization: evaluation and insights from eye movements BIBAKFull-Text 191-226
  Tomasz D. Loboda; Peter Brusilovsky
User-adaptive visualization and explanatory visualization have been suggested to increase educational effectiveness of program visualization. This paper presents an attempt to assess the value of these two approaches. The results of a controlled experiment indicate that explanatory visualization allows students to substantially increase the understanding of a new programming topic. Furthermore, an educational application that features explanatory visualization and employs a user model to track users' progress allows students to interact with a larger amount of material than an application which does not follow users' activity. However, no support for the difference in short-term knowledge gain between the two applications is found. Nevertheless, students admit that they prefer the version that estimates and visualizes their progress and adapts the learning content to their level of understanding. They also use the application's estimation to pace their work. The differences in eye movement patterns between the applications employing adaptive and non-adaptive explanatory visualizations are investigated as well. Gaze-based measures show that adaptive visualization captivates attention more than its non-personalized counterpart and is more interesting to students. Natural language explanations also accumulate a big portion of students' attention. Furthermore, the results indicate that working memory span can mediate the perception of adaptation. It is possible that user-adaptation in an educational context provides a different service to people with different mental processing capabilities.
Keywords: User-adaptation; Program visualization; Explanatory visualization; Eye movements; Eye tracking; Evaluation; User study; Working memory
Towards personality-based user adaptation: psychologically informed stylistic language generation BIBAKFull-Text 227-278
  François Mairesse; Marilyn A. Walker
Conversation is an essential component of social behavior, one of the primary means by which humans express intentions, beliefs, emotions, attitudes and personality. Thus the development of systems to support natural conversational interaction has been a long term research goal. In natural conversation, humans adapt to one another across many levels of utterance production via processes variously described as linguistic style matching, entrainment, alignment, audience design, and accommodation. A number of recent studies strongly suggest that dialogue systems that adapted to the user in a similar way would be more effective. However, a major research challenge in this area is the ability to dynamically generate user-adaptive utterance variations. As part of a personality-based user adaptation framework, this article describes personage, a highly parameterizable generator which provides a large number of parameters to support adaptation to a user's linguistic style. We show how we can systematically apply results from psycholinguistic studies that document the linguistic reflexes of personality, in order to develop models to control personage's parameters, and produce utterances matching particular personality profiles. When we evaluate these outputs with human judges, the results indicate that humans perceive the personality of system utterances in the way that the system intended.
Keywords: Natural language generation; Linguistic style; Personality; Individual differences; Big Five traits; Dialogue; Recommendation

UMUAI 2010-10 Volume 20 Issue 4

Using affective parameters in a content-based recommender system for images BIBAKFull-Text 279-311
  Marko Tkalcic; Urban Burnik; Andrej Košir
There is an increasing amount of multimedia content available to end users. Recommender systems help these end users by selecting a small but relevant subset of items for each user based on her/his preferences. This paper investigates the influence of affective metadata (metadata that describe the user's emotions) on the performance of a content-based recommender (CBR) system for images. The underlying assumption is that affective parameters are more closely related to the user's experience than generic metadata (e.g. genre) and are thus more suitable for separating the relevant items from the non-relevant. We propose a novel affective modeling approach based on users' emotive responses. We performed a user-interaction session and compared the performance of the recommender system with affective versus generic metadata. The results of the statistical analysis showed that the proposed affective parameters yield a significant improvement in the performance of the recommender system.
Keywords: Affective modeling; Content-based recommender system; Emotion induction; IAPS; Item profile; Machine learning; Metadata; User profile; Valence-arousal-dominance
Towards affective camera control in games BIBAKFull-Text 313-340
  Georgios N. Yannakakis; Héctor P. Martínez
Information about interactive virtual environments, such as games, is perceived by users through a virtual camera. While most interactive applications let users control the camera, in complex navigation tasks within 3D environments users often get frustrated with the interaction. In this paper, we propose inclusion of camera control as a vital component of affective adaptive interaction in games. We investigate the impact of camera viewpoints on psychophysiology of players through preference surveys collected from a test game. Data is collected from players of a 3D prey/predator game in which player experience is directly linked to camera settings. Computational models of discrete affective states of fun, challenge, boredom, frustration, excitement, anxiety and relaxation are built on biosignal (heart rate, blood volume pulse and skin conductance) features to predict the pairwise self-reported emotional preferences of the players. For this purpose, automatic feature selection and neuro-evolutionary preference learning are combined providing highly accurate affective models. The performance of the artificial neural network models on unseen data reveals accuracies of above 80% for the majority of discrete affective states examined. The generality of the obtained models is tested in different test-bed game environments and the use of the generated models for creating adaptive affect-driven camera control in games is discussed.
Keywords: Camera control; Player experience modeling; Skin conductance; Blood volume pulse; Neuro-evolution; Preference learning
User preferences can drive facial expressions: evaluating an embodied conversational agent in a recommender dialogue system BIBAKFull-Text 341-381
  Mary Ellen Foster; Jon Oberlander
Tailoring the linguistic content of automatically generated descriptions to the preferences of a target user has been well demonstrated to be an effective way to produce higher-quality output that may even have a greater impact on user behaviour. It is known that the non-verbal behaviour of an embodied agent can have a significant effect on users' responses to content presented by that agent. However, to date no-one has examined the contribution of non-verbal behaviour to the effectiveness of user tailoring in automatically generated embodied output. We describe a series of experiments designed to address this question. We begin by introducing a multimodal dialogue system designed to generate descriptions and comparisons tailored to user preferences, and demonstrate that the user-preference tailoring is detectable to an overhearer when the output is presented as synthesised speech. We then present a multimodal corpus consisting of the annotated facial expressions used by a speaker to accompany the generated tailored descriptions, and verify that the most characteristic positive and negative expressions used by that speaker are identifiable when resynthesised on an artificial talking head. Finally, we combine the corpus-derived facial displays with the tailored descriptions to test whether the addition of the non-verbal channel improves users' ability to detect the intended tailoring, comparing two strategies for selecting the displays: one based on a simple corpus-derived rule, and one making direct use of the full corpus data. The performance of the subjects who saw displays selected by the rule-based strategy was not significantly different than that of the subjects who got only the linguistic content, while the subjects who saw the data-driven displays were significantly worse at detecting the correctly tailored output. We propose a possible explanation for this result, and also make recommendations for developers of future systems that may make use of an embodied agent to present user-tailored content.
Keywords: Embodied conversational agents; Evaluation of generated output; Multimodal corpora; User-preference modelling

UMUAI 2010-12 Volume 20 Issue 5

Layered evaluation of interactive adaptive systems: framework and formative methods BIBAKFull-Text 383-453
  Alexandros Paramythis; Stephan Weibelzahl
The evaluation of interactive adaptive systems has long been acknowledged to be a complicated and demanding endeavour. Some promising approaches in the recent past have attempted tackling the problem of evaluating adaptivity by "decomposing" and evaluating it in a "piece-wise" manner. Separating the evaluation of different aspects can help to identify problems in the adaptation process. This paper presents a framework that can be used to guide the "layered" evaluation of adaptive systems, and a set of formative methods that have been tailored or specially developed for the evaluation of adaptivity. The proposed framework unifies previous approaches in the literature and has already been used, in various guises, in recent research work. The presented methods are related to the layers in the framework and the stages in the development lifecycle of interactive systems. The paper also discusses practical issues surrounding the employment of the above, and provides a brief overview of complementary and alternative approaches in the literature.
Keywords: Layered evaluation; Evaluation framework; Formative evaluation methods; Design
Learners' navigation behavior identification based on trace analysis BIBAKFull-TextErratum 455-494
  Nabila Bousbia; Issam Rebaï; Jean-Marc Labat
Identifying learners' behaviors and learning preferences or styles in a Web-based learning environment is crucial for organizing the tracking and specifying how and when assistance is needed. Moreover, it helps online course designers to adapt the learning material in a way that guarantees individualized learning, and helps learners to acquire meta-cognitive knowledge. The goal of this research is to identify learners' behaviors and learning styles automatically during training sessions, based on trace analysis. In this paper, we focus on the identification of learners' behaviors through our system: Indicators for the Deduction of Learning Styles. We shall first present our trace analysis approach. Then, we shall propose a 'navigation type' indicator to analyze learners' behaviors and we shall define a method for calculating it. To this end, we shall build a decision tree based on semantic assumptions and tests. To validate our approach, and improve the proposed calculation method, we shall present and discuss the results of two experiments that we conducted.
Keywords: Navigation type; Indicator; Trace; Web behavior analysis; Educational Hypermedia System