Thomas Lindh

Proposal and Experimental Evaluation of Fall Detection Solution Based on Wearable and Depth Data Fusion

Fall injury issues represent a serious problem for elderly in our society. These people want to live in their home as long as possible and technology can improve their security and independence. In this work we study the joint use of a camera based system and wearable devices, in the so called data fusion approach, to design a fall detection solution. The synchronization issues between the heterogeneous data provided by the devices are properly treated, and three different fall detection algorithms are implemented. Experimental results are also provided, to compare the proposed solutions.

Local Time Synchronization in Bluetooth Piconets for Data Fusion Using Mobile Phones

This paper presents a method to synchronize the clocks in a Bluetooth piconet from the application layer in a mobile phone. It adapts algorithms for time synchronization of distributed systems and the Internet to Bluetooth networks. The performance issues that cause problems for data synchronization between master and slaves in Bluetooth are highlighted. The tests show that the synchronization error is limited to one sampling time.

Measurement-Based Admission Control in Wireless Sensor Networks

Wireless sensor networks have today emerged as a feasible infrastructure for healthcare applications. This paper addresses the non-trivial performance problems in contention based wireless networks. We present a method for admission control in contention-based networks, implemented as a component of a performance management system. The test results show that admission control can improve the predictability and level of performance in wireless sensor networks. The system can be used as a tool for dimensioning and configuration as well as for real-time admission control. The often unpredictable dynamics in contention-based access networks means that continuous performance control is needed to maintain a desired quality of service.

Performance monitoring and control in contention-based wireless sensor networks

This paper presents a method for performance monitoring and control in wireless body sensor networks based on measurement feedback. Test results using a prototype implementation of the method are also analyzed. The method has been evaluated for demanding healthcare related applications in wireless personal area networks.

An end-to-end performance meter for applications in wireless body sensor networks

This paper presents a monitoring method and its implementation as a light-weight end-to-end performance meter for quality-demanding applications in wireless body sensor networks. The method is evaluated in a wireless sensor network testbed for healthcare applications.

Monitoring of SIP-Based Communication Using Signalling Information for Performance Measurements

This paper presents a prototype implementation of end-to-end monitoring of performance parameters in SIP-based communication. The approach is to integrate signalling information and measurements of user data traffic. Test measurements illustrate some results that can be obtained per session; packet loss, round-trip delays and their variation, inter-arrival jitter and throughput

A novel approach to multi-sensor data synchronisation using mobile phones

This paper presents a new algorithm for application layer synchronisation of data from multiple sensors arriving to a mobile phones Bluetooth interface. A system that provides feedback signals to an athlete is one example where it is crucial to synchronise data from several wireless sensors. This paper also discusses synchronisation problems caused by unpredictable Bluetooth transmission performance.

A performance monitoring method for wireless sensor networks

This paper presents a monitoring method and its implementation as a light-weight end-to-end performance meter for quality-demanding applications in wireless sensor networks. The use of performance feedback information for control and management is also considered. The method is evaluated in a wireless sensor network testbed for healthcare applications.

Performance Management in Switched ATM Networks

The introduction of switched virtual connections and valueadded services in ATM networks create new conditions for network management. A general model for performance management in switched broadband networks, based on interaction between management functions and control functions, is presented in this paper. Quality-of-service management in the service domain is also considered. Finally, in-service methods for monitoring of network performance (especially cell losses) in switched ATM networks are covered in more detail.

A novel approach to multi-sensor data synchronization using mobile phones

This paper presents a new algorithm for synchronization of data from multiple sensors arriving to a mobile phones Bluetooth interface with possibly unknown and different sampling frequencies. A system that provides feedback signals to an athlete is one example where it is crucial to synchronize data from several wireless sensors; especially sensor nodes use different and unknown sampling rates.