A frequent use of conversational user interfaces (CUIs) today is improving the users’ experience with online quantitative surveys. In this paper, we explore the use of CUIs in qualitative surveys. As a concrete use case, we adopt a specific, well-structured, qualitative research method called the repertory grid technique (RGT). We developed a hybrid user interface (HUI) that combines a graphical user interface (GUI) with a CUI to automate the distinct stages in a RGT survey. A pilot study was used to verify the feasibility of the approach and to fine-tune interface aspects of an initial prototype. In this paper, we report the results of a within-subject lab experiment with 24 participants that aimed to establish the performance and UX in a realistic context of a more advanced prototype. We observed a small decrease in UX in some hedonistic aspects, but also confirmed that the HUI performs similarly to a human agent in most pragmatic aspects. These results provide support for our hypothesis that automating qualitative surveys is possible with proper interface design. We hope that our work can inspire other researchers to design additional tools for qualitative survey automation, especially now that generative AI systems, such as ChatGPT, open up interesting new ways for computer systems to interact with users in natural language.

In a CHI paper from 10 years ago, entitled "Accounting for Diversity in Subjective Judgments", an interesting dichotomy was reported between, on the one side, the increased use of idiosyncratic constructs when judging the user experience of diverse products and, on the other hand, the statistical methods available to analyze such data. The paper more specifically proposed a method to extract diverse perspectives (called views) from experimental data. The current paper provides three improvements of this existing method by: 1) showing that a little-known approach for clustering attributes, called VARCLUS, can be applied and extended to provide a more optimal algorithm, 2) showing how the VARCLUS method can be applied to perform both within- and across-subject analysis, and 3) providing access to the VARCLUS method by incorporating it in ILLMO, a user-friendly and freely available program for interactive statistics.

The aim of this study was to validate the stability of the different factors of the Multidimensional Driving Style Inventory (MDSI) [16], which was originally developed and validated with participants in different geographical areas of Israel. In this study, the questionnaire was distributed in the Netherlands and Belgium. A factor analysis of the data of 364 participants revealed five of the eight factors that resulted from the original factor analysis: Angry driving, Anxious driving, Dissociative driving, Distress-reduction driving, and Careful driving style. In addition, 24 items divided over the five factors seem to be stable compared to the 44 items divided over the eight factors of the original analysis. The factors revealed through the analysis of these data were used to determine driver profiles, consisting of one or two driving styles. The next step is to compare self-report data on driving style to actual driving behaviour.

Creative processes involve a repertoire of digital devices ranging from mobile phones over tablets and desktop computers to electronic whiteboards and wall-sized displays. While some integration across multiple devices is supported more sophisticated kinds of integration that connect devices and amplify their potential are limited. Many creative practices also rely on physical materials and tools. This will workshop investigate how the combination of physical and digital artifacts can support creative work practices. In this context, we propose to examine: Individual and social creative activities; Creativity methods; Emergence and transformation of design ideas; Generative design materials; Design constraints.

Progress in empirical research relies on adequate statistical analysis and reporting. This article proposes an alternative approach to statistical modeling that is based on an old but mostly forgotten idea, namely Thurstone modeling. Traditional statistical methods assume that either the measured data, in the case of parametric statistics, or the rank-order transformed data, in the case of nonparametric statistics, are samples from a specific (usually Gaussian) distribution with unknown parameters. Consequently, such methods should not be applied when this assumption is not valid. Thurstone modeling similarly assumes the existence of anunderlying processthat obeys an a priori assumed distribution with unknown parameters, but combines this underlying process with a flexibleresponse mechanismthat can be either continuous or discrete and either linear or nonlinear. One important advantage of Thurstone modeling is that traditional statistical methods can still be applied on the underlying process, irrespective of the nature of the measured data itself. Another advantage is that Thurstone models can be graphically represented, which helps to communicate them to a broad audience. A new interactive statistical package, Interactive Log Likelihood MOdeling (Illmo), was specifically designed for estimating and rendering Thurstone models and is intended to bring Thurstone modeling within the reach of persons who are not experts in statistics.Illmois unique in the sense that it provides not only extensive graphical renderings of the data analysis results but also an interface for navigating between different model options. In this way, users can interactively explore different models and decide on an adequate balance between model complexity and agreement with the experimental data. Hypothesis testing on model parameters is also made intuitive and is supported by both textual and graphical feedback. The flexibility and ease of use ofIllmomeans that it is also potentially useful as a didactic tool for teaching statistics.

In this paper, we describe the iterative design and exploratory evaluation of ‘Amail’, an email tool designed for persons with aphasia. It is inspired by interviews with persons with aphasia and their partners and has been improved through discussions with experienced speech therapists. Our user studies show that aphasics find current email communication tools too challenging to use. The most pronounced barrier is the lack of writing support. Based on these findings, we designed an email application with language support and limited functionality that is easier to use than existing solutions. The email program has been evaluated in two complementary ways: (i) by collecting system logs as objective data and (ii) by conducting questionnaires and interviews with aphasics to understand their opinions, expectations and concerns. Our evaluation confirms that aphasics find the email tool easy to use and the language support is indeed a substantial help when composing emails. Moreover, participants demonstrated an increased confidence when composing messages using Amail. Suggestions for adaptations that could further improve the support for the target group were also collected.

While statistics is recognized as an important topic in the area of human-computer interaction (HCI) and other scientific fields, it is also a topic that spurns continuous debate. The current practice is that, despite extensive developments in the area of statistics in the last decades, most practitioners stick to the most simple parametric methods. Increasingly, we see the argument arise that scientists will have to resort to more advanced methods, which are unfortunately only available in advanced statistical packages that require a specialized syntax and a substantial understanding of the underlying statistical principles. This paper introduces Illmo, a program for performing statistics in a more intuitive way. In order to operate the program successfully, the user only needs to understand a single statistical principle, i. e., the likelihood as a goodness-of-fit measure between the observed data and the proposed statistical model. Illmo is unique in the sense that its visual interface not only provides extensive graphical renderings of the data analysis results, but also assists explicitly in navigating between different (but related) statistical techniques.

In this paper we present the design of an application that supports conversational storytelling for people with aphasia. Camelendar is a touch screen application that supports people with aphasia in expressive storytelling. Camelendar utilizes photos to support people with aphasia talking about their daily activities; participants of the conversation (including the aphasic person) add comments and detailed information to the photos, enriching the story each time it is told. By arranging photos visually on a calendar people with aphasia can navigate to photos of events they want to talk about. The photos of the events transform into stories by adding tags and comments directly on the photos.

Recent discussions in the interaction design community have called attention to sketching as an omnipresent element of any disciplined activity of design, and have pointed out that sketching should be extended beyond the simple creation of a pencil trace on paper. More specifically, the need to deal with all attributes of a user experience, especially the timing, phrasing, and feel of the interaction, has been identified. In this article, we propose extending the concept of sketching with a pencil on paper to the more generic concept of fluent exploration of interactive materials. We define interactive materials as any piece of software or hardware that represents or simulates a part of the interactive user experience, such as input from sensors, output in the form of sound, video, or image, or interaction with Web services or specialized programs. We have implemented the proposed concept within Sketchify, a tool for sketching user interfaces. Sketchify gives designers the freedom to manipulate interactive materials by combining elements of traditional freehand sketching with functional extensions and end-user programming tools, such as spreadsheets and scripting. We have evaluated Sketchify in the education of interaction designers, identifying both successful aspects and aspects that need further improvements.

Symbols are used in scatterplots to encode data in a way that is appropriate for perception through human visual channels. Color is believed to be the most dominant channel with lightness regarded as the most important one of three color dimensions. We study lightness perception in scatterplots in the context of analytic tasks requiring symbol discrimination. More specifically, we performed an experiment to measure human performance in three visual analytic tasks. Outlined circles and unframed spots, equally sized, with a uniform luminance that was varied at ten or eleven equispaced levels between black and white were used as symbols and displayed on a uniform white background. Sixteen subjects divided in two groups, participated in the experiment and their task performance times were recorded. We propose a model to describe the process. The perception of lightness is assumed to be an early step in the complex cognitive process to mediate discrimination, and psychophysical laws are used to describe this perceptual mapping. Different mapping schemes are compared by regression on the experimental data. The results show that approximate homogeneity of lightness perception exists in our complex tasks and can be closely described by a blended combination of two opposite power functions assuming either the light end or the dark end of the lightness scale as the starting point. The model further yields discriminability scales of lightness for sparse scatterplots with a white background.

Traditional desktop computers are known to offer insufficient functionality to designers. They are often complemented by pen-based tablet devices in order to better support key activities such as sketching and modeling. However, even such extended systems are restricted, as they insufficiently support other key activities of individual designers and design teams, such as collecting and sorting inspirational material, viewing and manipulating 3D models, brainstorming, discussing or presenting. Advanced visual interfaces, such as augmented surfaces, have been proposed as being potentially complimentary in this respect, as they can support multi-user interaction, bimanual interaction (even in 3D), and a better integration between physical and digital media. In this paper, we present Design TeamMate, a system in which individual workstations of designers are fluently integrated with an augmented tabletop and wall display. We discuss how this platform can support a wide range of individual and group design activities.

People have always relied on visual tools such as maps, charts and diagrams to better understand problems and solve them in less time. Continuous improvements in computer processing power and graphics capabilities have made it possible to incorporate a wide range of advanced visualization techniques in most computing application domains, including business, medicine, engineering and science.

Symbols are used in scatterplots to encode data in a way that is appropriate for perception through human visual channels. Symbol size is believed to be the second dominant channel after color. We study symbol size perception in scatterplots in the context of analytic tasks requiring size discrimination. More specifically, we performed an experiment to measure human performance in three visual analytic tasks. Circles are used as the representative symbol, with eight, linearly varying radii; 24 persons, divided across three groups, participated; and both objective and subjective measures were obtained. We propose a model to describe the results. The perception of size is assumed to be an early step in the complex cognitive process to mediate discrimination, and psychophysical laws are used to describe this perceptual mapping. Different mapping schemes are compared by regression on the experimental data. The results show that approximate homogeneity of size perception exists in our complex tasks and can be closely described by a power law transformation with an exponent of 0.4. This yields an optimal scale for symbol size discrimination.

The current paper proposes a novel method of analyzing goal-directed movements by dividing them into distinct movement intervals. We demonstrate how the description of the first and second most prominent movement intervals in terms of duration and length can provide insight into the applied movement strategies under different conditions. This method, although demonstrated for goal-directed movements, has the potential to be generalized to other types of movements, such as steering movements.

In this paper we present the design of an image capturing device for persons with aphasia. The early concepts were validated with one speech therapist and the usability of the camera was tested with one aphasic person. Our semi-autonomous hand-held camera, tapered to meet specific interaction and ergonomic needs of expressive aphasics. This camera is able to capture daily experiences by creating photographs that receives significant, automatically added tags. We present the design case study with early evaluation results by proxy users.

A wealth of studies in the field of user experience have tried to conceptualize new measures of product quality and inquire into how the overall goodness of a product is formed on the basis of product quality perceptions. An interesting question relates to how the perception as well as the relative dominance of different product qualities evolve across different phases in the adoption of a product. However, temporality of experience poses substantial challenges to traditional reductive evaluation approaches. In this paper we present an alternative methodological approach for studying how users’ experiences with interactive products develop over time. The approach lies in the elicitation of rich qualitative insights in the form of experience narratives, combined with content-analytical approaches for the aggregation of idiosyncratic insights into generalized knowledge. We describe a tool designed for eliciting rich experience narratives retrospectively, and illustrate this tool by means of a study that inquired into how users’ experiences with mobile phones change over the first 6 months of use. We use the insights of the study to validate and extend a framework of temporality proposed by Karapanos et al. (2009b).

Symbols are frequently used to represent data objects in visualization. An appropriate contrast between symbols is a precondition that determines the efficiency of a visual analysis process. We study the contrast between different types of symbols in the context of scatterplots, based on user testing and a quantitative model for symbol contrast. In total, 32 different symbols were generated by using four sizes, two classes (polygon-and asterisk shaped), and four categories of rotational symmetry; and used three different tasks. From the user test results an internal separation space is established for the symbol types under study. In this space, every symbol is represented by a point, and the visual contrasts defined by task performance between the symbols are represented by the distances between the points. The positions of the points in the space, obtained by multidimensional scaling (MDS), reveal the effects of different visual feature scales. Also, larger distances imply better symbol separation for visual tasks, and therefore indicate appropriate choices for symbols. The resulting configurations are discussed, and a number of patterns in the relation between properties of the symbols and the resulting contrast are identified. In short we found that the size effect in the space is not linear and more dominant than shape effect.

In this paper we argue against averaging as a common practice in the analysis of subjective attribute judgments, both across and within subjects. Previous work has raised awareness of the diversity between individuals' perceptions. In this paper it will furthermore become apparent that such diversity can also exist within a single individual, in the sense that different attribute judgments from a subject may reveal different, complementary, views. A Multi-Dimensional Scaling approach that accounts for the diverse views on a set of stimuli is proposed and its added value is illustrated using published data. We will illustrate that the averaging analysis provides insight to only 1/6th of the total number of attributes in the example dataset. The proposed approach accounts for more than double the information obtained from the average model, and provides richer and semantically diverse views on the set of stimuli.

A recent trend in Human-Computer Interaction (HCI) research addresses human needs that go beyond the instrumental, resulting in an increasing body of knowledge about how users form overall evaluative judgments on the quality of interactive products. An aspect largely neglected so far is that of temporality, i.e. how the quality of users' experience develops over time. This paper presents an in-depth, five-week ethnographic study that followed 6 individuals during an actual purchase of the Apple iPhone". We found prolonged use to be motivated by different qualities than the ones that provided positive initial experiences. Overall, while early experiences seemed to relate mostly to hedonic aspects of product use, prolonged experiences became increasingly more tied to aspects reflecting how the product becomes meaningful in one's life. Based on the findings, we promote three directions for CHI practice: designing for meaningful mediation, designing for daily rituals, and designing for the self.

The study of aimed movements has a long history, starting at least as far back as 1899 when Wood-worth proposed a two-component model in which aimed movements are broken into an initial ballistic phase and an additional control phase. In this paper, we use Wood-worth's model for experimentally comparing aimed movements in the real world with those in a virtual environment. Trajectories from real world movements have been collected and compared to trajectories of movements taken from a virtual environment. From this, we show that significant temporal differences arise in both the ballistic and control phases, but the difference is much larger in the control phase; users' improvement is relatively greater in the virtual world than in the real world. They progress more in ballistic phase in the real world, but more in correction phase in the virtual world. These results allow us to better understand the pointing tasks in virtual environments.

A plethora of reaching techniques, intended for moving objects between locations distant to the user, have recently been proposed and tested. One of the most promising techniques is the Radar View. Up till now, the focus has been mostly on how a user can interact efficiently with a given radar map, not on how these maps are created and maintained. It is, for instance, unclear whether or not users would appreciate the possibility of adapting such radar maps to particular tasks and personal preferences. In this paper, we address this question by means of a prolonged user study with the Sketch Radar prototype. The study demonstrates that users do indeed modify the default maps in order to improve interactions for particular tasks. It also provides insights into how and why the default physical map is modified.

In this paper, we describe two projects aimed at designing a tool for documenting and reporting everyday experiences by aphasics. Proxy feedback on design concepts was used to select concepts for further in-depth prototyping. Both final prototypes use automated image capturing and provide a means for browsing the collected images. One design is mobile and separates picture taking from picture viewing, while the other design is a larger static object that integrates image input and output.

A plethora of reaching techniques, intended for moving objects between locations distant to the user, have recently been proposed and tested. One of the most promising techniques is the Radar View. Up till now, the focus has been mostly on how a user can interact efficiently with a given radar map, not on how these maps are created and maintained. It is for instance unclear whether or not users would appreciate the possibility of adapting such radar maps to particular tasks and personal preferences. In this paper we address this question by means of a prolonged user study with the Sketch Radar prototype. The study demonstrates that users do indeed modify the default maps in order to improve interactions for particular tasks. It also provides insights into how and why the default physical map is modified.

In our studies aimed at understanding design practice we have identified the creation of mood boards as a relevant task for designers. In this paper we introduce an interactive wall-mounted display system that supports the presentation of mood boards. The system allows designers to easily record their mood board presentations while capturing the richness of their individual presentation skills and style. Designers and clients can play back, explore and comment on different aspects of the presentation using an intuitive and flexible interaction based on hand gestures thus supporting two-way communication. The system records the presentation and organizes it into three information layers (i.e. gesture, sound and visuals), which are first used to segment the presentation into meaningful parts, and later for playback. Exploratory evaluations show that designers are able to use the system with no prior training, and see a practical use of the proposed system in their design studios.

This paper discusses a design case, which explores the potential of psychophysiological measures as an input technique for social gaming applications intended for children. aMAZEd is an example of a tabletop mixed reality game that supports social interaction between players through and around the game. It is clear that sensing technology used to obtain psychophysiological measures needs to be improved and there is still a range of solutions that need to be explored. However, our experience shows that psychophysiological input appeals to children and can be a fun element of games supporting social interaction among players.

The research on Tangible Interaction (TI) has been inspired by many different disciplines, including psychology, sociology, engineering and human-computer interaction (HCI). Now that the field is getting more mature, in the sense that basic technologies and interaction paradigms have been explored, we observe a growing potential for a more design-oriented research approach. We suggest that there are several arguments for this proposed broadening of the TI-perspective: 1) the need for designing products within contexts-of-use that are much more challenging and diverse than the task-oriented desktop (or tabletop) systems that mostly inspire us today, 2) the interest to also design TI starting from existing physical activities instead of only as add-ons to digital applications, 3) the need for iterative design and evaluation of prototypes in order to develop applications that are grounded within daily practice over prolonged periods of time, and 4) the need to extend ease-of-use to more hedonic aspects of interaction such as fun and engagement

Even in the current computer age, there are still many important application areas, such as early architectural design, where traditional tools like sketching on paper continue to be preferred by many professionals over computer-based tools. There is a growing awareness that there are often very good grounds for this preference. Hence, instead of trying to replace such traditional ways of working, it is now often considered more opportune to try and preserve the strengths of these traditional ways of working, while at the same time improving them by providing access to new media. This is one of the main objectives of the augmented reality approach that we adopt here. In this paper, we specifically discuss the realization of a tool for early architectural design on an existing augmented reality system, called the Visual Interaction Platform. We describe the development process, the resulting tool and its performance for elementary tasks such as positioning and overdrawing. We also identify directions for future research and applications.

Color is routinely used to visualize interval and ordinal data, while texture is not. For color, a variety of perceptually based models is available, which can be used to convey data via straightforward mapping. The dimensionality of texture is less well understood and there are almost no perceptually based and validated models available to generate textures on demand. We present a perceptually based texture synthesis model for isotropic textures. The model uses additive synthesis of band-limited noise in the spectral domain, comparable to the RGB (red, green, blue) model for color. Via user experiments, we have derived a three-dimensional model to control the amplitudes per band in a perceptually intuitive way, comparable to the HSV (hue, saturation, value) model for color. The three dimensions used are contrast, spatial frequency, and spectral purity. Besides a mapping to the amplitudes, we have derived a mapping to a perceptually equidistant space. We show how such textures can be combined with color; applications are presented.

Visualization via direct volume rendering is a potentially very powerful technique for exploring and interacting with large amounts of scientific data. However, the available two-dimensional (2D) interfaces make three-dimensional (3D) manipulation with such data very difficult. Many usability problems during interaction in turn discourage the widespread use of volume rendering as a scientific tool. In this paper, we present a more in-depth investigation into one specific interface aspect, i.e., the positioning of a clipping plane within volume-rendered data. More specifically, we propose three different interface prototypes that have been realized with the help of wireless vision-based tracking. These three prototypes combine aspects of 2D graphical user interfaces with 3D tangible interaction devices. They allow to experience and compare different user interface strategies for performing the clipping plane interaction task. They also provide a basis for carrying out user evaluations in the near future.

Augmented tabletops can be used to create multi-modal and collaborative environments in which natural interactions with tangible objects that represent virtual (digital) information can be performed. Such environments are considered potentially interesting for many different applications. In this paper, we address the question of whether or not it makes sense to use such environments to design learning experiences for young children. More specifically, we present the "Read-It" application that we have created to illustrate how augmented tabletops can support the development of reading skills. Children of five-to-seven-years old were actively involved in designing and testing this application. A pilot experiment was conducted with a prototype of the Read-It application, in order to confirm that it does indeed meet the a priori expectations. We hope that the Read-It application will inspire the development of more tabletop applications that are targeted at specific user groups and activities.

In this paper, multidimensional models of image quality are discussed. In such models, alternative images, for instance, obtained through different processing or coding of the same scene, are represented as points in a multidimensional space. The positioning is such that the correlation between geometrical properties of the points and the subjective impressions mediated by the corresponding images is optimized. More specifically, perceived dissimilarities between images are monotonically related to interpoint distances, while the strengths of image quality attributes (such as perceived noise and blur or image quality) are, for instance, monotonically related to point coordinates along specified directions. The goal of multidimensional models is to capture subjective impressions into a single picture that is easy to interpret. We apply multidimensional models to two existing data sets to demonstrate that they indeed account very well for experimental data on image quality. The program XGms is introduced as a new interactive tool for constructing multidimensional models from experimental data. Although XGms is introduced here within the context of image-quality modeling, it is also potentially useful in other applications that rely on multidimensional models.

We introduce new theoretical results on how the local differential structure in images can be described, processed, and coded efficiently by means of the Hermite transform. It is shown that the Hermite transform can take many alternative forms, all of which have their specific advantages. The various forms of the Hermite transform correspond to different ways of coding the local orientation in the image, and we describe a systematic theory, based on well-known principles from vector spaces, for deriving such alternative forms. One specific case, called the sampled Hermite transform, is shown to be especially interesting for adaptive image processing and coding. An application in the field of adaptive noise reduction is included by way of illustration.

We propose that the Hermite transform can bridge the gap between conventional transform coding techniques and second-generation coding techniques that make use of explicit descriptions of perceptually important image structures (e.g., contours and lines). This claim is motivated by two important characteristics of the Hermite transform. First, it shows good image analysis properties in detecting and extracting (local) image features such as orientation and position. Second, extracted image features can be used to steer the Hermite transform into a form with high energy compaction properties.

With limited additional effort, one can obtain valuable information on the subjective performance of image compression schemes. The choice of an appropriate experimental technique, however, is not always trivial. We show that the different nature of the artifacts introduced by different coders causes problems when evaluations are carried out using direct numerical category scaling. We demonstrate this by comparing the results of a direct scaling method and a scaling technique in which subjects have to determine quality differences between all possible combinations of coded images.

We demonstrate that the relationship between images degraded by noise and blur on the one hand and judgements on noisiness, perceived blur and overall quality by subjects on the other hand can be characterized in a multi-dimensional perceptual space. In this perceptual space, the images are represented by points, and the strengths of their perceptual attributes are modeled by the projections of these image positions onto attribute axes. In analogy with the perceptual space, we introduce a psychometric space in which the positions of the images are determined by objective measures on the images. We show that this psychometric space can also be used to predict perceptual image quality and its underlying attributes noisiness and perceived blur.

A class of simple noise-reduction and contrast-enhancement algorithms is presented. In these algorithms, the image is decomposed locally into its mean value and residue image, and the relative weight of each component is altered under the control of a contrast measure that is obtained through quadratic filtering of the input image. This adaptive residue-image processing technique can be implemented with few operations per pixel and is hence suitable for real-time applications. Moreover, it performs well, is flexible and generalizes several existing algorithms.>

We present a new technique for image interpolation based on polynomial transforms. This is an image representation model that analyzes an image by locally expanding it into a weighted sum of orthogonal polynomials. In the discrete case, the image segment within every window of analysis is approximated by a finite set of polynomial coefficients. We show how the problem of interpolating an image can be approached by interpolating the smooth window function used to locally analyze the image. Comparison with the existing interpolation techniques illustrates the good performance of the method presented in this paper.

The continuous formulation of scale space is briefly reviewed. It is shown that deriving a discrete formulation of scale space requires the solution to a more general problem; the optimum approximation of a signal by local patterns. The consequences of the theory for the Laplacian image pyramid are discussed. A pyramid coding scheme based on the discrete scale-space formulation is derived. Preliminary coding results on real images are presented. Down to 1 b/pixel, the quality of the coded images is usually very close to that of the originals. Bit rates below 0.5 b/pixel imply a too coarse quantization, or even deletion, of the prediction error image at the smallest scale and, consequently, always result in images that are noticeably unsharp. In the intermediate region, different degrees of quantization noise and unsharpness are present. At comparable data rates, the linear variation coder generates less quantization noise in uniform regions, while the scale-space coder gives a slightly better edge reproduction.>