One of the numerous applications of wearable computers is providing safety in occupations where heat-related injuries are prevalent. Core temperature, as a parameter that cannot be measured by on-body sensors is a variable that is specifically interesting for realizing such applications. In the context of the design of a sensor-shirt that can be used by firefighters, in this paper we study the importance of different types of sensor measurements and their placement for estimating core temperature. We propose a model for inferring the dangerous states of core temperature. Our evaluation results show that our model can to a great extent estimate hazardous situations caused by heat accumulation.

Mobile devices can help to solve urban traffic problems by improving personal mobility and making transport, traveling, and commuting for individual users more flexible, sustainable, and rewarding. For that purpose, the tripzoom application combines mobility data and patterns from mobile sensing, a dynamic incentive system, and community feedback from social networks. This paper gives an overview of tripzoom, its features, and technical realization, and explains how users can take advantage of it to monitor, manage, and improve their mobility behavior.

The accelerating growth of cities provides new challenges for urban planning, especially related to transportation. Many existing infrastructures already operate at their limits during rush hours or large events. They need to be used more efficiently as they often cannot be extended without considerable negative effects for citizens such as increasing pollution or travel costs. We describe a framework that enhances mobility data from existing urban infrastructure with data from participatory sensing. Based on derived mobility patterns and direct feedback via social networks, a dynamic incentive system is provided to positively influence mobile behavior on a personal and city-wide scale beyond regular urban planning. We present the design and architecture of such a system and point out critical issues and proposed solutions in an initial implementation aimed towards real world tests in several cities.

Knowing the location of different sensed user tokens such as a Bluetooth-enabled mobile phone or RFID badge helps to verify the identity of the user. Co-location of the tokens increases the confidence that the user is at a certain location whereas conflicting locations decreases this confidence. Thus location information can be used to authenticate the user. Instead of sensing user tokens viawireless communication channels, face detection and recognition can be used as well. The location of the webcam detecting the user can be fused with location information obtained from other user identity tokens. Together with the face recognition output, the fused location information of the sensed identity tokens results in an enhancement of the user identification process. This approach proves very accurate in terms of a reduction of the FAR and FRR of the face recognition, allows for more relaxed posing of the user for reasonably correct face recognition, and provides user- friendliness as users don't have to explicitly enter credentials anymore in order to authenticate themselves. The latter aspect makes the approach suitable for pervasive and ubiquitous computing environments.

We exploit the ability to sense and use context information to augment or replace the traditional static security measures by making them more adaptable to a given context and thereby less intrusive. We demonstrate that by fusing location information obtained from various sources that are associated to the user and are available over time, the confidence in the identity of the user can be increased considerably. In fact, the level of confidence in the identity of the user is related to the probability that the user is at a certain location. This probability is used as a measure to parameterize the authentication level of the user making it thereby much more adaptive to changing situational circumstances. In this paper we describe the theoretical background for a context-sensitive adaptation of authentication and the design and validation of the system that we have developed to adaptively authenticate a user on the basis of the location of his sensed identity tokens.

We investigate the practical feasibility of using context information for controlling access to services. Based solely on situational context, we show that users can be transparently provided anonymous access to services and that service providers can still impose various security levels. Thereto, we propose context-sensitive verification methods that allow checking the user's claimed authenticity in various ways and to various degrees. More precisely, conventional information management approaches are used to compare historic contextual (service usage) data of an individual user or group. The result is a relatively strong, less intrusive and more flexible access control process that mimics our natural way of authentication and authorization in the physical world.

In this paper we present a Web services-based platform that facilitates and speeds up the development and deployment of context-aware, integrated mobile speech and data applications. The platform is capable of handling different types of context and offers sophisticated personalization mechanisms. To illustrate the usefulness of the platform and to validate the claim that cross-platform application development, in particular mobile, context-aware applications is easier and faster with Web services technologies, we present a demonstration application. It serves tourists with interesting information and services in their specific context, and contributes to the achievement of their current goals. Finally, we present a number of problems that we experienced in the implementation process as well as the feedback that we received from real users who tested our application.

—Next generation mobile service delivery puts very high demands on context-aware and personalization enabling technologies. Context-awareness and personalization of our Personalized Service Environment (PSE) [7] is achieved by the integration of a complex set of those technologies imposing the constraints of different entities such as wireless and fixed networks, end-devices, services, users and businesses. Our PSE concept heavily hinges on a so-called " brokerage system " that controls and manages the delivery of future mobile services [8]. In this paper we investigate additional brokerage functionality that is needed to enforce privacy of the parties involved in delivering mobile services. To this end, a mobile service can be considered as an ensemble of so-called sub-services, where each sub-service is controlled and managed by a " brokerage subsystem ". Our study of middle agents for the Internet [9] yields a specification of a " brokerage subsystem " in terms of how it preserves privacy of the actors involved in requesting and delivering the corresponding sub-service. A well-designed combination of these brokerage subsystems can enforce context and user depending privacy requirements. We build a context-aware personalized scheduling service for a mobile business-to-employee (B2E) setting, where software agents collectively arrange new meetings at different locations and times keeping in mind the upcoming meetings of the employees. The software agents also simultaneously look after privacy or security policies of the employees or their companies, e.g. with respect to location information, time schedules, personal preferences or business sensitive information. We developed and deployed our scheduling service on the JADE-agent platform using PDA's and small notebooks connected to a server using WLAN and GPRS networks.

When users are traveling to a scheduled meeting and the location and time of the planned meeting has to be changed while they are still on the road, this requires exchange of user related information like their current location and privacy settings to define and schedule a new meeting. This distributed scheduling problem has been solved using a Scheduler Agent System (SAS) based on software agents that act on behalf of their users. The SAS has been employed on an agent platform that connects negotiating scheduler agents on servers with agents that run on small wireless end-devices. An interaction algorithm was developed for negotiation about location and time. This algorithm was successfully implemented into software agents, enabling them to negotiate and finally agree on the rescheduled meeting.

This paper describes initial results of the Amsterdam Living Lab project. It discusses a reference architecture for measurement systems to determine user behavior in mobile living lab settings. Such a reference architecture has a goal to act as (i) a common vocabulary among people that communicate about living labs, (ii) a blueprint for future implementations and (iii) a guideline for comparison of living lab measurement systems. The architecture is a work in progress that will be evaluated and refined in the coming period.