Reading with Mobile Phone & Large Display

In this paper we compare performance and usability between three different device combinations: a) mobile phone b) touch screen c) mobile phone & screen. We show that mobile phone & screen has a better perform-ance than phone only. We also discuss some interaction issues when using a mobile phone with a large screen

Supporting Device Discovery and Spontaneous Interaction with Spatial References

The RELATE interaction model is designed to support spontaneous interaction of mobile users with devices and services in their environment. The model is based on spatial references that capture the spatial relationship of a user’s device with other co-located devices. Spatial references are obtained by relative position sensing and integrated in the mobile user interface to spatially visualize the arrangement of discovered devices, and to provide direct access for interaction across devices. In this paper we discuss two prototype systems demonstrating the utility of the model in collaborative and mobile settings, and present a study on usability of spatial list and map representations for device selection

Using a Spatial Context Authentication Proxy for Establishing Secure Wireless Connections

Spontaneous interaction in wireless ad-hoc networks is often desirable not only between users or devices in direct contact, but also with devices that are accessible only via a wireless network. Secure communication with such devices is difficult because of the required authentication, which is often either password- or certificate-based. An intuitive alternative is context-based authentication, where device authenticity is verified by shared context, and often by direct physical evidence. Devices that are physically separated cannot experience the same context and thus cannot benefit directly from context authentication. We introduce a context authentication proxy that is pre-authenticated with one of the devices and can authenticate with the other by shared context. This concept is applicable to a wide range of application scenarios, context sensing technologies, and trust models. We show its practicality in an implementation for setting up IPSec connections based on spatial reference. Our specific scenario is ad-hoc access of mobile devices to secure 802.11 WLANs using a mobile device as authentication proxy. A user study shows that our method and implementation are intuitive to use and compare favourably to a standard, password-based approach

Spatially aware user interfaces for spontaneous interaction

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Integrating spatial information in a user interface

Indoor location systems enable mobile devices to gather location information of other devices or services. Applications such as the Relate Meeting Tool [2] have been built that support cross-device interaction without explicitly knowing an address for the target device. However, little is known about how to integrate this spatial information into the user interface in an effective way. This poster introduces our approach and presents preliminary results

Usage of Spatial Information for Selection of Co-located Devices

Use of spatial information to support discovery of interaction opportunities has been widely demonstrated. In this paper, we focus on the use of spatial interfaces for identification and selection of devices a mobile user encounters in their immediate environment. We contribute an experimental evaluation of two spatial interface conditions in comparison with a non-spatial condition. The two spatial interface conditions are a device list ordered by distance and an iconic map of devices as seen from the user’s perspective and the non-spatial condition is an alphabetical list. Our results show an overall user preference for the iconic map over the spatial and alphabetical list. However, there was no clear preference for the spatial interfaces over the non-spatial condition with respect to user satisfaction and mental load

Visibility of individual packet loss on H.264 encoded video stream:a user study on the impact of packet loss on perceived video quality

Assessing video content transmitted over networked content infrastructures becomes a fundamental requirement for service providers. Previous research has shown that there is no direct correlation between traditional network QoS and user perceived video quality. This paper presents a study investigating the impact of individual packet loss on four types of H.264 main-profile encoded video streams. Four artifact factors to model the degree of artifacts in video frames are defined. Further, the visibility of artifacts considering the video content characteristics, encoding scheme and error concealment is investigated in conjunction with a user study. The individual and joint impacts of artifact factors are explored on the test video sequences. From the results of user tests, the artifact factor-based assessment method shows superiority over PSNR-based and network QoS based quality assessment