The center for Data-intensive Systems (Daisy) at Aalborg University is currently working on a large project in which they combine the two worlds of Web 2.0 and Location-based services.

The project known as the StreamSpin-project currently employs numerous developers. Furthermore it is planned that students will have the opportunity to develop their own services for the system during the coming semesters in order to mature the system and its service deliveries.

It is the overall purpose of the StreamSpin project to be for Location-based services what YouTube is for video . Thereby, the vision is that virtually anybody should be able to create their own services and publish them to the masses or limit the publication to close friends.

The motivation behind the project is the vision that the web now is becoming more and more mobile. Hence the need for Location-based services will grow massively in the near future. People using mobile phones with GPS or other positioning systems will have the possibility of knowing their position at a given time.

This opens up for numerous advantageous scenarios in which a user of a mobile phone could retrieve information based on position, time and a customizable pro le. Systems that displays this behavior already exist, however the StreamSpin-project proposes that services are pushed to the mobile device rather than requested by the mobile device itself.

The aim of this short paper is to cover the most important issues involving the creation of services for the StreamSpin-project. This includes understanding the StreamSpin server structure and creating a service for publishing and consuming these services. Furthermore it is highly advisable to read the material available on the StreamSpin web page before continuing onwards in this paper as some concepts might stand clearer afterwards.

Creating Services for StreamSpin
Initially it is important to understand what StreamSpin is capable of and what it consist of. As mentioned in the introduction StreamSpin is a middle-layer service that allows information and services to be pushed directly to a mobile device. Hence only the following requirements are needed:
• Mobile device either with Windows Mobile 5 or Java MIDP 2.0 and GPS receiver [2]
• Access to a server with a server-side HTML scripting language (like PHP or ASP.Net)

The team behind StreamSpin provides a client application for use with the mobile device on both platforms. This client is most helpful for testing purposes. The client can be downloaded on the StreamSpin web site. However it is also possible to test StreamSpin without the usage of a mobile device. This is done by creating locations for the users pro le and simulates moves by selecting these in an emulation of the Windows Mobile 5 client. When the service to be created needs to be pushed according to the users location, some script must be executed to reload the content which must be pushed to the mobile device.

Download pdf How to Use StreamSpin for Creating Your Own Services