A Lab Server Model for the iLab Shared Architecture

Introduction

Nowadays many online laboratories are available in a quite large number of educational institutions. They cover different fields of science and engineering education and allow end users (students, trainees, teachers and researchers) to access laboratory workbenches via the Internet. Most of these laboratories are closely tailored to the needs of the owner institutions, but important projects exist to promote sharing of equipment and experiments across multiple institutions, and to encourage cooperation and scaling to large numbers of users worldwide.

The iLabs project of the Massachusetts Institute of Technology (MIT) (MIT iCampus: iLabs, 2005) appears as the most advanced initiative to promote a distributed architecture of online laboratories: the iLab Shared Architecture (ISA). The latter is a service oriented framework providing a set of services and tools to support sharing of online labs. ISA allows users to access laboratories through a single sign-on administrative interface. The interactions among the ISA components are well defined and documented by MIT developers and an open source implementation of the architecture is available. Simple examples in the open source package help to develop laboratory servers participating in the network. The ISA does not concern itself with the control of experimental setups and user interfaces to experiments. These tasks are completely left to the developers of the laboratory servers.

In this chapter we contribute to the creation of networks of online laboratories by proposing the model of a scalable and general purpose laboratory server and its integration into ISA. The lab server has been designed to control heterogeneous devices and can be easily adapted to different fields of application. The communications between the laboratory server and the end user interfaces, and between the laboratory server and the devices are completely mediated by web services. The model provides plug & play functionality to simplify the management of experiments (including associated software and hardware components) thus minimizing changes to the lab server core when experimental setups change. We applied the proposed server model to the development of an online laboratory on Digital Signal Processing (DSP).

Subsequently, our focus has shifted toward the integration of the DSP laboratory server into ISA. The examples of lab servers, which are available in the distribution package of iLabs, have been very useful. Nevertheless a careful analysis of the ISA modalities of integration of interactive labs suggested the design of a new interface to connect the laboratory. The aim has been to simplify the integration and to make it independent from the server technology, and to minimize the changes to be done on existing laboratory servers to join the iLabs network. The new interface, named LabProxy, is now present in the software repository of the iLabs project.

The chapter is organized as follows: the next section provides information on the evolution of online laboratories and on the current challenge of creating networks of laboratories. Then, we provide details on the proposed laboratory server model and on the open source project that we are carrying on to support the developers of new laboratories. Finally, we present the DSP laboratory, our test bed for the server model and we discuss the integration of this laboratory into ISA, introducing the LabProxy module.