Software Architectures For Remotely Operable Civil Engineering Laboratories

Educators have successfully adapted many classroom courses to distance education environments via the internet and are now attempting to extend this success to laboratory courses by allowing students to remotely control and observe various experiments. A key task that arises in this process of modifying the experiments in traditional laboratories for internet-enabled control and observation is the development of a secure computational framework that uses web technologies and computer networking concepts to communicate information between the computers of the laboratory and the remote user. This framework that enables internet access to the experiment must address two main issues : (1) protection for the computers that directly operate the experiment from malignant users on the internet, and (2) portability of the framework to other experiments. In this paper, we propose a framework that addresses these concerns and illustrate it for a shaketable experiment. The framework is designed to act as an intermediary between client and server applications that are developed for data acquisition and control. The key component of the framework is a proxy server. It controls access to the computers that perform data acquisition and control. A webserver that is hosted on the proxy server serves webpages related to the experiment. The webserver has user-based authentication protocols to authenticate users attempting to access the webpages. The webserver uses a combination of perl scripts and linux networking tools to setup access to the experiment for the remote user and later, disable access for the remote user when the allotted timeslot expires.