Rico Wind

Seamless Indoor/Outdoor Positioning Handover for Location-Based Services in Streamspin

This paper presents the implementation of a novel seamless indoor/outdoor positioning service for mobile users.The service is being made available in the Streamspin system(www.streamspin.com), an open platform for the creation and delivery of location-based services. Streamspin seeks to enable the delivery of truly ubiquitous location-based services by integrating GPS and Wi-Fi location fingerprinting. The paper puts focus on key aspects of the seamless handover between outdoor to indoor positioning. Several different handover solutions are presented,and their applicability is evaluated with respect to positioning accuracy and battery consumption of the mobile device.

User-Generated Content: The Case for Mobile Services

Enabling user-generated services could help fuel the mobile revolution. Web sites that enable the sharing of user- generated content such as photos and videos are immensely popular, and their use is on the rise. Technologies that enable Web sites to support the creation, sharing, and deployment of user-generated mobile services could be key factors in the spread of the mobile Internet.

Algorithmic strategies for adapting to environmental changes in 802.11 location fingerprinting

Ubiquitous and accurate indoor positioning represents a key capability of an infrastructure that enables indoor location-based services. At the same time, such positioning has yet to be achieved. Much research uses commercial, off-the-shelf 802.11 (Wi-Fi) hardware for indoor positioning. In particular, the dominant fingerprinting technique uses a database (called a radio map) of manually collected Wi-Fi signal strengths and is able to achieve positioning accuracies that enable a wide range of location-based services. However, a major weakness of fingerprinting occurs when changes occur in the indoor environment that cause the signal propagation patterns and thus signal strength to change. Under such circumstances, a radio map collected at one time is unable to offer accurate positioning at all times. We propose a data-centric approach to achieving accurate positioning in changing environments. Unlike previous work, our approach does not require the deployment of special sensors that capture current signal strength phenomena, but rather lends itself towards ubiquitous indoor positioning. An empirical comparison of our proposals against conventional, static radio maps demonstrates very significant improvements in positioning accuracy in changing environments.

A Testbed for the Exploration of Novel Concepts in Mobile Service Delivery

This paper describes an open, extendable, and scalable system that supports the delivery of context-dependent content to mobile users. The system enables users to receive content from multiple content providers that matches their demographic data, active profiles, and context such as location and time. The system also allows users to subscribe to specific services. In addition, it allows users to provide their own content and services, by either using the systems publicly available interface or by filling out one of the service-configuration templates.

Pretty Easy Pervasive Positioning

With the increasing availability of positioning based on GPS, Wi-Fi, and cellular technologies and the proliferation of mobile devices with GPS, Wi-Fi and cellular connectivity, ubiquitous positioning is becoming a reality. While offerings by companies such as Google, Skyhook, and Spotigo render positioning possible in outdoor settings, including urban environments with limited GPS coverage, they remain unable to offer accurate indoor positioning. We will demonstrate a software infrastructure that makes it easy for anybody to build support for accurate Wi-Fi based positioning in buildings. All that is needed is a building with Wi-Fi coverage, access to the building, a floor plan of the building, and a Wi-Fi enabled device. Specifically, we will explain the software infrastructure and the steps that must be completed to obtain support for positioning. And we will demonstrate the positioning obtained, including how it interoperates with outdoor GPS positioning.

Seamless indoor/outdoor positioning with streamspin

This paper presents the implementation of novel seamless indoor/outdoor positioning service for mobile users. When users are not within GPS range, the service exploits the wifi access point infrastructure for positioning. A central server stores wifi radio maps and map images that are then sent to user terminals based on the mac addresses of nearby access points. The positioning services is available in Streamspin (www.streamspin.com), which is an open and scalable platform for the creation and delivery of location-based services. With this new service, the system enables the easy creation and deployment of mobile services that rely on seamless indoor/outdoor positioning.

Algorithmic Strategies for Adapting 802.11 Location Fingerprinting to Environmental Changes

1 Summary This paper studies novel algorithmic strategies that enable 802.11 location fingerprinting to adapt to environmental changes. A long-standing challenge in location fingerprinting has been that dynamic changes, such as people presence, opening/closing of doors, or changing humidity levels, may influence the 802.11 signal strengths to an extent where a static radio map is rendered useless. To counter this effect, related research efforts propose to install additional sensors in order to adapt a previously built radio map to the circumstances at a given time. Although effective, this is not a viable solution for ubiquitous positioning where localization is required in many different buildings. Instead, we propose algorithmic strategies for dealing with changing environmental dynamics. We have performed an evaluation of our algorithms on signal strength data collected over a two month period at Aalborg University. The results show a vast improvement over using traditional static radio maps. 2 Description In recent years outdoor positioning and navigation systems have become household commodities due to continuously dropping costs of accurate GPS equipment. To facilitate an equally wide scale consumer adoption of positioning and navigation in indoor spaces, 802.11 (Wi-Fi) is an obvious technological choice due to the ubiquity of Wi-Fi infrastructures and the proliferation of Wi-Fi- (and GPS-) enabled mobile devices. Due to the somewhat unpredictable propagation patterns of Wi-Fi signals in indoor environments, the so-called location fingerprinting technique, which relies on empirically measured signal strengths, has yielded the best results in terms of obtainable positioning accuracy.