Jyri P. Salomaa

mWSN for Large Scale Mobile Sensing

This paper reviews the state-of-the-art features introduced by sink mobility into wireless sensor networks (WSN), and introduces the architecture of mobile enabled Wireless Sensor Network (mWSN) to realize large-scale information gathering via networked wireless sensors and mobile sinks. After introducing the mobile sensing scenarios, some fundamental design parameters in mWSN have been investigated, such as cluster size, sink velocity, transmission range, and packet length. Our contributions include: (1) A cluster formation method has been proposed via multihop forwarding to form a cluster around the expected position of a mobile sink, in order to guarantee packet delay and minimize energy consumption. (2) Analysis of the performance influence by sink mobility leads to the conclusion that the optimal sink velocity must make a compromise between sink-sensor meeting delay and message delivery delay. (3) Finding that large transmission range and short packet length are both of benefit to lower the outage probability of packet transmission. Extensive simulations have been designed to evaluate the performance of mWSN in terms of packet delay, energy consumption and outage probability of packet transmission.

Simulation Study of Cluster Based Data Dissemination for Wireless Sensor Networks with Mobile Sinks

Recent years have witnessed increasing research efforts of incorporating mobility into wireless sensor networks in order to improve energy efficiency and network coverage. In particular, after introducing mobile sinks, at the cost of increased message delivery delay, the performance of network lifetime can be significantly enhanced by limiting the hop count between the communicating sensor-sink pair. In this paper, we propose a cluster based data dissemination (CBDD) scheme, which does not require any localization algorithm. The basic idea of CBDD is to divide the communication between mobile sinks and source sensors into inter-cluster and intra-cluster communication phases, and limit the disruption of the data dissemination path within a cluster. Through extensive simulations, we compare the performance of CBDD against AODV (ad hoc on-demand distance vector) and TTDD (two-tier data dissemination), which are two popular routing protocols for mobile wireless sensor networks. Simulation results have indicated that CBDD is a good option for data dissemination in wireless sensor networks with mobile sinks.

A user study of mobile web services and applications from the 2008 Beijing Oympics

This paper describes a business user study using a packaged suite of mobile Web services and applications deployed at a real-time event, the Beijing Olympic Games in August 2008. These applications were an Olympics guide, menu reader, phrasebook, Sports Tracker [3], photo sharing on Ovi [4], and Nokia Maps [2]. To evaluate its feasibility and use, we used logging, surveys, and statistical analysis for collecting and analyzing the data. We discovered that guests found the Olympics guide application to be the most popular, followed by Nokia Maps and then photo sharing on Ovi. The results demonstrate that the techniques used in our evaluation can be used to determine the type of applications that are relevant to consumers at a real-time event, and suggests ways for improving the mobile application design and user experience.

User study on family communication in China

Family is a core element of society. The development of economics and the transformation of cultures in mainland China bring new challenges to family communications. To understand current practices and the needs of family communication in mainland China, we studied 27 rural and urban families with ethnographic methods. We summarized the main family structures for rural and urban families and also found three main family communication problems: emotional communication, the education of children and elder support. These three problems exist in both rural and urban areas, but in different forms. Two concepts, an emotional poster in village and a learning community based on family/village clan, were designed and presented to address the problems.