Understanding human mobility patterns is essential for efficient traffic management, but collecting personal trajectories has strong privacy implications. Although there are several anonymization approaches for trajectories, there is a lack of research on how applying these methods to large realistic datasets affects the trade-off between privacy and utility in real-world use cases. To close this research gap, we investigated how the use of a k-anonymized trajectory dataset affects key use cases in traffic management. We interviewed experts from several city councils to identify a set of relevant and realistic use cases in traffic management. For two of those use cases, we then created synthetic movement data using traffic simulations in SUMO for Berlin, Boston and Lisbon. We reduced these datasets to three 30-minute time slots for each city, representing the busiest, the least busy, and median traffic load of the simulation and anonymized them using a generalized k-anonymity approach. Compared to the original dataset, we found that for small k, the analysis of the anonymized dataset on inter-district movement patterns led to similar results. For larger k, results differed substantially. Using the anonymized dataset for congestion analysis did not yield meaningful results for any k. Results for different cities varied substantially across all use cases and k. Our findings indicate that using anonymized trajectories may be feasible for some traffic management use cases but requires careful consideration of anonymization methods, parameter choice and the structure and traffic patterns of the analyzed urban area.

Abstract Social distancing is one of the key measures to lower infections during a pandemic. Pedestrian signage is one way to achieve this by managing the flow of people to reduce crowdedness. However, visual signs can clutter the environment and might not be noticed by pedestrians. In this paper, we propose auditory displays for managing pedestrian flow. We developed implicit and explicit sound signs, evaluated them in a user study with 16 participants and compared our results to those reported for visual signage. Our results show that auditory signs are as effective as visual signs in managing the flow of people. Although using explicit sounds tends to be more effective than using implicit sounds, our findings indicate a tendency for implicit sounds to be preferred by participants with respect to environmental comfort. Our work contributes to the understanding of auditory displays and facilitates investigating further uses beyond pedestrian flow management during a pandemic.

Abstract Physical distancing is a key measure to slow the spread of many highly infectious diseases, e.g. COVID-19. Streetscape interventions such as pedestrian signage can contribute to ensuring distances are kept, but it is unclear to what extent people comply with these in practice. This paper tackles this question using an immersive video environment to realistically simulate real-life streetscapes in the lab. In a controlled user study, we augmented panoramic video footage with pedestrian one-way street signage and recorded route decisions to assess compliance with distance keeping measures. Our results indicate that such signage affects routing decisions and can thus help pedestrians to avoid crowded situations where distance keeping is difficult. We also identified further factors affecting decisions and a correlation between intention to comply and actual compliance. The experimental method we used enabled us to effectively and safely carry out a study of a phenomenon that in the real world depends on interaction with the physical environment. This method may have applications in other areas in which simulations of physical environments are important.

Citizen participation is an important part of urban planning but few people participate, and most frequently they can do so only passively. This can result in excluding many people and to urban designs not reflecting people’s wishes. In this paper, we explore the use of interactive, immersive public displays as facilitators for deeper participation in urban planning. We propose a novel approach that combines panoramic videos of locations with overlays depicting planned buildings. We evaluated it in a lab-based user study (N = 21), where participants used a simple mobile client for interacting with a prototypical implementation to vote/comment on urban planning proposals. Usefulness, ease of use, ease of learning and user satisfaction were all rated highly by the participants. The pros and cons of the approach were further identified based on the analysis of the interview data. Overall, the results provide initial evidence that the approach succeeded in facilitating deeper participation.

Deictic expressions – such as uttering ”this tool” and pointing at a hammer – are important and frequent elements of everyday communication. They are used, for example, when conveying location and orientation information, or when identifying objects. Pointing gestures exist among all known cultures, languages and ethnicities, but they depend on parties to be collocated. When communicating across distances, deictic expressions are usually lost. In this paper, we introduce an approach for communicating deictic pointing across distances by simulating the sender hand posture in the receiver’s hand using electrical muscle stimulation (EMS). We describe our prototypical implementation of this approach and report on a lab-based user study evaluating it. Our results indicate that it is technically feasible to use EMS for communicating deictic pointing gestures across distances. Participants in our study were successful in resolving deictic expressions consisting of verbal and gestural components. Furthermore, our results provide initial insights into user behavior, user satisfaction and specific challenges in this context. Our contributions can inform the design of future interfaces for naturally transmitting pointing gestures across distances.

Geoinformatics deals with spatial and temporal information and its analysis. Research in this field often follows established practices of first developing computational solutions for specific spatiotemporal problems and then publishing the results and insights in a (static) paper, e.g. as a PDF. Not every detail can be included in such a paper, and particularly, the complete set of computational steps are frequently left out. While this approach conveys key knowledge to other researchers it makes it difficult to effectively re-use and reproduce the reported results. In this vision paper, we propose an alternative approach to carry out and report research in Geoinformatics. It is based on (computational) reproducibility, promises to make re-use and reproduction more effective, and creates new opportunities for further research. We report on experiences with executable research compendia (ERCs) as alternatives to classic publications in Geoinformatics, and we discuss how ERCs combined with a supporting research infrastructure can transform how we do research in Geoinformatics. We point out which challenges this idea entails and what new research opportunities emerge, in particular for the COSIT community.

While lab-based approaches to evaluation of location-based services (LBSs) allow faster, cost-effective and less complicated evaluation of many aspects, they are limited in evaluating certain aspects, especially the ones related to usability and user experience (UX). Variations in the location information quality can negatively affect location-based UX. Lab-based evaluations are limited in factoring users' actual context, which includes location quality variations into the evaluation process. Therefore, to evaluate actual location-based UX, we need to evaluate LBSs in-the-wild with users under variations in the quality of location information. Currently, there is a lack of standard tools, methods, and frameworks for this purpose. Motivated by this factor, in this paper, we describe the Location Uncertainty Injection Framework (LUIF) for evaluating mobile LBSs in-the-wild with users under location quality variations. We also present the results of a study conducted to gain initial feedback on the potential use cases of the framework.

Degraded GPS signals can negatively affect users of mobile Pedestrian Navigation Applications. Visualization of location uncertainty has emerged as a solution to this problem that has proven beneficial to users. However, there are only a small number of different visualizations developed for this purpose. In addition, their actual impact on facilitating navigation in GPS degraded situations has not been studied well. We designed two new visualizations of location uncertainty and compared them to existing ones in terms of efficiency and user acceptance. A field-based user study(N=18) showed that the two new visualizations significantly reduced the number of wrong turns. Users preferred the landmark-based visualization most and ranked it as the most helpful visualization for judging their true location in the environment when faced with GPS degradations. Despite participants being unfamiliar with the new visualizations, the task completion time, subjective task load and user experience for them were not significantly different from the more familiar state-of-the-art visualization.

Reproducibility is a cornerstone of science and thus for geographic research as well. However, studies in other disciplines such as biology have shown that published work is rarely reproducible. To assess the state of reproducibility, specifically computational reproducibility (i.e. rerunning the analysis of a paper using the original code), in geographic research, we asked geoscientists about this topic using three methods: a survey (n = 146), interviews (n = 9), and a focus group (n = 5). We asked participants about their understanding of open reproducible research (ORR), how much it is practiced, and what obstacles hinder ORR. We found that participants had different understandings of ORR and that there are several obstacles for authors and readers (e.g. effort, lack of openness). Then, in order to complement the subjective feedback from the participants, we tried to reproduce the results of papers that use spatial statistics to address problems in the geosciences. We selected 41 open access papers from Copernicus and Journal of Statistical Software and executed the R code. In doing so, we identified several technical issues and specific issues with the reproduced figures depicting the results. Based on these findings, we propose guidelines for authors to overcome the issues around reproducibility in the computational geosciences.

The growing dissemination of geographic information systems (GIS) in recent years has increased the availability and use of geospatial tools. Despite this trend in GIS, usability is often not considered, and studies on usability are relatively rare. However, it has been shown that the effectiveness, efficiency and user satisfaction of these tools when used for geospatial tasks may be impacted by their design and terminology. In this article, we present a comprehensive review of the relevant literature. We analyze and compare publications of GIS usability evaluations, the methods that were used, and the findings reported. We thus produce a more detailed picture of GIS usability evaluations. Our contributions are (1) an overview of methods applied in case studies for evaluating the usability of GIS; (2) the identification of gaps and resulting weaknesses of previous studies; and (3) challenges and opportunities for future GIS usability studies. Our findings reveal a lack of usability guidelines for GIS, a lack of methods for analyzing complex workflows, and a lack of usage studies over longer periods of time. These contributions can help GIS developers and designers to improve the usability of their systems.

Many scientific publications report on computational results based on code and data, but even when code and data are published, the main text is usually provided in a separate, traditional format such as PDF. Since code, data, and text are not linked on a deep level, it is difficult for readers and reviewers to understand and retrace how the authors achieved a specific result that is reported in the main text, e.g. a figure, table, or number. In addition, to make use of new the opportunities afforded by data and code availability, such as re-running analyses with changed parameters, considerable effort is required. In order to overcome this issue and to enable more interactive publications that support scientists in more deeply exploring the reported results, we present the concept, implementation, and initial evaluation of bindings. A binding describes which data subsets, code lines, and parameters produce a specific result that is reported in the main text (e.g. a figure or number). Based on a prototypical implementation of these bindings, we propose a toolkit for authors to easily create interactive figures by connecting specific UI widgets (e.g. a slider) to parameters. In addition to inspecting code and data, readers can then manipulate the parameter and see how the results change. We evaluated the approach by applying it to a set of existing articles. The results provide initial evidence that the concept is feasible and applicable to many papers with moderate effort.

Open government datasets (OGD) have been flooding the Web in recent years. Geovisualisations are the natural way of making sense of them, and have been gradually coming out. However, one key problem is the lack of flexibility of these visualizations, which severely limits their re-use in new scenarios. This article therefore proposes to increase the intelligence of existing geovisualisations by incorporating five features, to make better use of OGD: (i) automatic geographic data type recognition, (ii) generation of geovisualisation designs, (iii) monitoring of users' understanding of geographic facts, (iv) self-optimization, and (v) user activity recognition. In addition to benefiting users of OGD, realizing these features presents rich scientific challenges and opportunities for Geovisualization research, the OGD landscape (and beyond).

Participatory design (PD) in HCI has been successfully applied to vulnerable groups, but further research is still needed on forced migrants. We report on a month-long case study with a group of about 25 young forced migrants (YFMs), where we applied and adapted strategies from PD and participatory research (PR). We gained insights into the benefits and drawbacks of combining PD and PR concepts in this particular scenario. The PD+PR approach supported intercultural collaborations between YFMs and young members of the host community. It also enabled communication across language barriers by using visual and “didactic reduction” resources. On a theoretical level, the experiences we gained allowed us to reflect on the role of “safe spaces” for participation and the need for further discussing it in PD. Our results can benefit researchers who take part in technology-related participatory processes with YFMs.

While it is commonplace to retrieve photos showing a particular feature (e.g. through tools such as Google Pictures or Bing Images), spatial approaches for retrieving videos showing a particular feature (e.g. a building) have yet to be established. This article proposes five ranking algorithms to query georeferenced videos for a specific feature based on the videos' spatio-temporal metadata. 12 relevance criteria for feature-centric video ranking were compiled from a focus group discussion. From these, four criteria have been selected for implementation: "Feature Depiction", "Feature Illumination", "Feature Visibility Duration", and "Distance to Feature". These criteria were implemented in five algorithms and evaluated regarding efficiency and user perceived plausibility. The evaluation suggests that the "Feature Visibility Duration" of the video's viewshed with the queried feature geometry offers a good trade-off between computationally performant and cognitive plausible ranking. The obtained results are relevant to user-centered approaches for interacting with georeferenced videos.

Mobile systems provide many means to relay information to a distant partner, but remote communication is still limited compared to face-to-face interaction. Deictic communication and pointing, in particular, are challenging when two parties communicate across distances. In this paper, we investigate how people envision remote pointing would work when using mobile devices. We report on an elicitation study where we asked participants to perform a series of remote pointing tasks. Our results provide initial insights into user behaviors and specific issues in this context. We discovered that most people follow one of two basic patterns, that their individual pointing behavior is very consistent and that the shape and location of the target object have little influence on the pointing gesture used. From our results, we derived a set of design guidelines for future user interfaces for remote pointing. Our contributions can benefit designers and researchers of such interfaces.

A key problem in the area of citizen engagement is to make people aware of opportunities to participate and to motivate them to take action. We propose an approach that uses geofences and proactive notifications on mobile devices to raise citizen awareness of engagement opportunities in situ and to trigger the exploration of these opportunities. Notifications are automatically triggered in the near vicinity of engagement opportunities based on space, time, and user preferences. We conducted two user studies to investigate our approach. A field-based study revealed specific usage patterns and motivational aspects of the situated discovery of engagement opportunities. A lab-based comparison study investigated the pragmatic and hedonistic qualities of our application. Results indicate that users prefer to be informed in situ even when they do not necessarily interact with notifications straight away.

Real-time synchronization is increasingly available in web-based environments for editing textual data, and this has changed how groups of people collaborate. We present a novel approach for real-time collaborative editing of geo-data. We introduce Ethermap, an open source web-application that implements this approach and enables multiple users to map data concurrently. It supports synchronous and collaborative mapping in several ways: it visually highlights mapping activities, it allows for fine-grained reviewing of all changes, and it enhances text-based communication with cross-modal references to geo-objects. We report on key results from a multi-tiered evaluation of Ethermap based on a user-study and on expert interviews. The concept of real-time collaborative editing was received favorably by users and experts. Participants of the study learned to use Ethermap quickly, and successfully completed a collaborative mapping task. Experts and users agreed that, given the right scenario (e.g., disaster mapping, teaching, planning), the approach could benefit the process of working on geo-data collaboratively.

Public displays have become ubiquitous in many places regularly visited by large numbers of people (e.g., traffic hubs or malls). In addition to advertising they often provide information related to the location (e.g., time tables). However, individuals can have difficulties to find information relevant to them -- either due to information overload or lack of personalization. Multiplexing, as defined in information theory, can help to address this issue by increasing the number of available channels. We propose three methods for visual multiplexing, and report on a controlled lab-based comparison study. Our results indicate that visual multiplexing via mobile devices can be a feasible solution to provide personalized multimedia content on public displays, and that the three methods tested differ in terms of performance. We found that the content type shown has an impact on which method works best, and that self-reported workload differed according to content type and multiplexing method.

The proliferation of location-based services in recent years has highlighted the need to consider location privacy. This has led to the development of methods enhancing location privacy, and to the investigation of reasons for sharing location information. While computational attacks on location privacy and their prevention have attracted a lot of research, attacks based on humans strategies and tactics have mostly been considered implicitly. This note addresses this knowledge gap by reporting on a user study, which we conducted in the context of a location-based game. Participants had to identify other players over the course of several weeks. The results show that human strategies for deanonymization and re-identification can be highly successful and thus pose a threat to location privacy comparable to computational attacks. By incorporating real-world knowledge (that is not easily available in automated attacks), human players were able to efficiently identify other people in the game.

Gestures can offer an intuitive way to interact with a computer. In this paper, we investigate the question whether gesturing with a mobile phone can help to perform complex tasks involving two devices. We present results from a user study, where we asked participants to spontaneously produce gestures with their phone to trigger a set of different activities. We investigated three conditions (device configurations): phone-to-phone, phone-to-tabletop, and phone to public display. We report on the kinds of gestures we observed as well as on feedback from the participants, and provide an initial assessment of which sensors might facilitate gesture recognition in a phone. The results suggest that phone gestures have the potential to be easily understood by end users and that certain device configurations and activities may be well suited for gesture control.

Landmarks are a key element in navigation and have been used extensively to provide navigation support to pedestrians through mobile devices in urban areas. Natural environments differ significantly from built environments in a number of ways including, for example, the degree of structure and regularity, the types and density of landmarks, and the way in which people navigate in those environments. In this paper, we investigate how people currently navigate 'in the wild', and whether landmark-based navigation support through mobile devices is a feasible option in such settings. We present results from two studies: a questionnaire-based study focussing on current practice and the use of landmarks, and a qualitative lab-based study using immersive panoramic photographs and photographs of (natural) landmarks investigating the feasibility of landmark-based navigation support in natural environments. The results indicate that a small number of means are currently used for navigation in the wild, and that certain types of landmarks might be feasible for navigation support on mobile devices. We also found initial evidence that immersive panoramic photographs may constitute a promising way to evaluate mobile applications.

The main objective of the third workshop on Multi-User and Ubiquitous User Interfaces (MU3I 2006) is to bring people with relevant backgrounds (e.g. interface design, CSCW, ubiquitous computing) together to discuss two key questions in this field: How can we build interfaces, which span multiple devices so that the user knows that they can be used to control a specific application? How can we build interfaces for public displays? Therefore, the main outcome of the workshop is expected to consists of further insights into those problems, potential solutions and a research agenda to investigate these further.

As the number of public displays in the environment increases, new opportunities open up to improve situated interaction and to enable new kinds of applications. In order to make distributed display resources available to nomadic users, a key issue to address is how control can be dynamically shared between display users. It is important to study how control over a shared display can be acquired, released or shared by nomadic and residential users given their competing demands for display resources.In this paper, we present a system and a user study investigating these issues in the context of two applications both competing for display resources provided by a deployment of interactive office doorplates. The first application (Hermes II) provides situated note leaving and messaging services whereas the second one (GAUDI) supports user navigating a university department. Office occupants (i.,e. residential users) can control whether the navigation application may (temporarily) use their doorplate display (thus giving priority to the navigation needs of nomadic users to the department). We report on findings from a user study, and discuss interface design implications for specifying display control.

A key issue in mobile and ambient computing is the effort required to rapidly prototype and evaluate user interfaces and applications. Existing technologies for these tasks suffer either from low fidelity (e.g. paper prototypes, mental walkthroughs) or effectively require a near full-scale deployment. We propose an approach using immersive video with surround sound and a simulated infrastructure to create a very realistic environment in the office or the lab. It provides a low-cost and rapid means to prototype user interfaces and applications, and to evaluate them in a realistic simulation of the context, in which they are intended to be used.

This second workshop on Multi-User and Ubiquitous User Interfaces aims at further investigating two major issues identified at last year's MU3I: control and consistency. The former relates to how a user gains control of devices in a ubiquitous computing environment, how control is passed, and how it is shared in such a setting. The second one concerns interfaces that span multiple devices or move from one set of devices to another. Both issues will be discussed in this year's workshop (with a focus on consistency.

In this paper, we describe a public navigation system which uses adaptive displays as directional signs. The displays are mounted to walls where they provide passersbys with directional information. Each sign is an autonomous, wirelessly networked digital displays connected to a central server. The signs are position-aware and able to adapt their display content in accordance with their current position. Advantages of such a navigation system include improved flexibility, dynamic adaptation and ease of setup and maintenance.

One of the most promising possibilities for supporting user interaction with public displays is the use of personal mobile phones. Furthermore, by utilising Bluetooth users should have the capability to interact with displays without incurring personal financial connectivity costs. However, despite the relative maturity of Bluetooth as a standard and its widespread adoption in today's mobile phones, little exploration seems to have taken place in this area - despite its apparent significant potential. This paper describe the findings of an exploratory study involving our Hermes Photo Display which has been extended to enable users with a suitable phone to both send and receive pictures over Bluetooth. We present both the technical challenges of working with Bluetooth and, through our user study, we present initial insights into general user acceptability issues and the potential for such a display to facilitate notions of community.

AIMS 2005 is the sixth workshop in a series of events that investigate various topics at the intersection of applied artificial intelligence and mobile computing. The main goal of this year's workshop is to discuss AI methods and approaches that enable adaptive and intelligent user interfaces in a mobile setting. Relevant topics include (but are not limited to) context awareness, resource adaptation and interaction metaphors in mobile and/or ubiquitous systems. The workshop combines technical presentations with focussed discussion to drive interaction between participants.

If a mobile computing device knows how it is positioned and oriented in relation to other devices nearby, then it can provide enhanced support for multi-device and multi-user interactions. Existing systems that provide position information to mobile computers are reliant on externally deployed infrastructure, such as beacons or sensors in the environment. We introduce the Relate system, which provides fine-grained relative position information to co-located devices on the basis of peer-to-peer sensing, thus overcoming dependence on any external infrastructure. The system is realised as a hardware/software plug-in, using ultrasound for peer-to-peer sensing, USB to interface with standard mobile devices, and data abstraction and inferencing to map sensor data to a spatial model that maintains both quantitative and qualitative relationships. We present a set of services and applications to demonstrate the utility of the system. We report experimental results on the accuracy of the relative position and orientation estimates, and other aspects of system performance.

Location information can be used to enhance interaction with mobile devices. While many location systems require instrumentation of the environment, we present a system that allows devices to measure their spatial relations in a true peer-to-peer fashion. The system is based on custom sensor hardware implemented as USB dongle, and computes spatial relations in real-time. In extension of this system we propose a set of spatialized widgets for incorporation of spatial relations in the user interface. The use of these widgets is illustrated in a number of applications, showing how spatial relations can be employed to support and streamline interaction with mobile devices.

In this paper, we evaluate several means of presenting route instructions to a mobile user. Starting from an abstract language-independent description of a route segment, we show how to generate various presentations for a mobile device ranging from spoken instructions to 3D visualizations. We then examine the relationship between the quality of positional information, available resources and the different types of presentations. The paper concludes with guidelines that help to determine which presentation to choose for a given situation

This demo will present Tellmaris and Deep Map, two system offering navigational assistance and other services to an untrained user. We will put an emphasis on different ways to present route instructions on mobile devices.