Albrecht Schmidt

Interacting with the computer using gaze gestures

This paper investigates novel ways to direct computers by eye gaze. Instead of using fixations and dwell times, this work focuses on eye motion, in particular gaze gestures. Gaze gestures are insensitive to accuracy problems and immune against calibration shift. A user study indicates that users are able to perform complex gaze gestures intentionally and investigates which gestures occur unintentionally during normal interaction with the computer. Further experiments show how gaze gestures can be integrated into working with standard desktop applications and controlling media devices.

Eye-gaze interaction for mobile phones

In this paper, we discuss the use of eye-gaze tracking technology for mobile phones. In particular we investigate how gaze interaction can be used to control applications on handheld devices. In contrast to eye-tracking systems for desktop computers, mobile devices imply several problems like the intensity of light for outdoor use and calibration issues. Therefore, we compared two different approaches for controlling mobile phones with the eyes: standard eye-gaze interaction based on the dwell-time method and gaze gestures. Gaze gestures are a new concept, which we think has the potential to overcome many of these problems. We conducted a user study to see whether people are able to interact with applications using these approaches. The results confirm that eye-gaze interaction for mobile phones is attractive for the users and that the gaze gestures are an alternative method for eye-gaze based interaction.

Mobile interaction with the real world: an evaluation and comparison of physical mobile interaction techniques

Mobile devices are more and more used for mobile interactions with things, places and people in the real world. However, so far no studies have discussed which interaction techniques are preferred by users in different contexts. This paper presents an experimental comparison of four different physical mobile interaction techniques: touching, pointing, scanning and user-mediated object interaction. To evaluate these techniques across different scenarios and to collect real usage data, four prototypes were implemented: a system for mobile interaction in smart environments, a mobile tourist guide, a mobile museum guide and a prototype for mobile interaction with advertisement posters. In each setting an experimental comparison was performed. Based on the results of these studies, which involved over 60 participants in total, advantages and disadvantages of these interaction techniques are described. Context-specific user preferences are presented for the interaction techniques, to help application designers and developers decide which interaction technique(s) to integrate into their application and which consequences this decision has.

Supporting Mobile Service Usage through Physical Mobile Interaction

Although mobile services can be used ubiquitously, their employment and the interaction with them are still restricted by the constraints of mobile devices. In order to facilitate and leverage mobile interaction with services, we present a generic framework that combines semantic Web service technology and physical mobile interaction. This interaction paradigm uses mobile devices to extract information from augmented physical objects and use it for a more intuitive and convenient invocation of associated services. For that purpose, the presented framework exploits Web service descriptions for the automatic and dynamic generation of customizable user interfaces that support and facilitate physical mobile interaction. This generic approach to mobile interaction with services through the interaction with physical objects promises to meet the complementary development of the Internet of things. A user study with a prototype application for mobile ticketing confirms our concept and shows its limits

Pervasive RFID and Near Field Communication Technology

Today, RFID enjoys enormous interest as the first widely deployed pervasive technology, and Near Field Communication will be the first widely deployed technology enabling humans to communicate with physical objects. This article reports on the Pertec (Pervasive RFID/Near Field Communication Technology and Applications) workshop, which discussed the future evolution of RFID beyond goods identification, including sensor integration, localization, NFC applications, and emerging challenges.

Tracking the interaction of users with AJAX applications for usability testing

In this paper, we introduce an implementation for detailed monitoring of user actions on web pages. It addresses the problem that the log data recorded by standard web servers is not sufficient for the tracking of users on AJAX websites, e.g. to conduct a usability test. Using standard web technologies, our HTTP proxy can record very detailed usage information, such as mouse movements, clicks, key presses and scrolling, together with the exact HTML DOM tree objects involved. As we show in several case studies, the tracking also works across multiple websites, none of which needs to be under our control. This approach is much less invasive than previous efforts: The test person does not need to install software on her computer, and in certain operation modes, no configuration changes at all are required on her computer. Our research indicates that if the technology described in this paper is employed, arbitrary visitors of a website are more likely to take part in a usability test offered by that site -- this facilitates recruiting test participants over the Internet.

A Capacitive Sensing Toolkit for Pervasive Activity Detection and Recognition

In this paper we present a toolkit for realizing capacitive sensing applications for human-computer interaction in pervasive computing systems. We argue that capacitive sensors - due to their unique properties - are well suited for many pervasive and ubiquitous computing applications and scenarios. We describe the CapToolKit designed to rapidly realize prototypes and systems that are able to detect the presence of humans and objects. Our toolkit also allows the integration of 3D interaction with everyday objects as well as instrumented environments. We illustrate its capabilities by presenting several applications implemented using CapToolKit. The entire system will be open-sourced to allow utilization of our technology within other research projects. By building on the existing toolkit researchers are provided a foundation for developing their own sensor systems, algorithms, and applications

Designing, Developing, and Evaluating Context-Aware Systems

Context and context-awareness have been central issues in ubiquitous computing research for the last decade. Advances with regard to context acquisition and activity recognition allow interesting small scale applications. However in larger systems including many sensors and actuators and spanning multiple administrative domains are still remain as unsolved central issues. Particularly, in the areas of reasoning and context-fusion there are many open questions. In this paper we motivate large scale context-aware systems that have support for the full life cycle using a prototype that was implemented and tested. We then describe in detail the underlying architecture which supports dynamic context-aware systems and includes mechanisms for context fusion and reasoning. Also, we propose a new approach for evaluating context-aware systems. The approach is an adapted expert evaluation; well known in the user interface domain, but using a carefully selected set of heuristics specifically targeted at context-aware systems.

CapTable and CapShelf - Unobtrusive Activity Recognition Using Networked Capacitive Sensors

In this paper, we introduce two pieces of activity-sensing furniture using networked capacitive sensors. CapTable and CapShelf are two example applications for activity detection and context acquisition realized with the CapSensing Toolkit. Both instances are representatives of a greater class of scenarios where networked sensing can compete with other technologies. CapTable is a simple wooden table equipped with capacitive sensors. Hand and body motion can be tracked above and around the table with high resolution. Additionally, conductive and non- conductive objects can be tracked and discriminated. The same features apply to CapShelf, a shelf that can monitor where people are reaching, and partially track the amount of items still in the shelf. We argue, that capacitive sensors provide huge benefits for real-world, privacy-sensitive, and unobtrusive data acquisition and implicit human-computer interaction.

A proxy-based infrastructure for web application sharing and remote collaboration on web pages

When people collaborate remotely, the WWW is part of the shared resources they use together. However, web pages do not offer support for collaborative interaction such as viewing or influencing another users browsing session - additional software needs to be installed for these features. In this paper, we present UsaProxy 2, an HTTP proxy that allows the same web page or application to be viewed and used in two browsers at the same time, without client-side software installation. This includes a visualisation of the remote users mouse pointer, scrolling, keyboard input, following links to other pages and more. Our open-source proxy modifies HTML pages before delivering them to the browsers. The added JavaScript code provides session monitoring and shared browsing facilities. We conducted an experimental evaluation which shows that our approach works for different scenarios, such as shopping online and exchanging ideas on what to buy. The user study showed that our approach is accepted and liked by users. Combined with audio or text chat communication, it provides a very useful tool for informal, ad-hoc collaboration.