Dial-In Flow Cytometry Data Analysis Facilitated by Web Servlet
Francis L. Battye
The Walter & Eliza Hall Institute
There are obvious benefits to the centralized storage of experimental data provided that convenient access via network connections is possible. However, the size of modern flow cytometry data files discourages their transmission over commonly used analog telephone modem connections. A solution lies in the nature of the data itself: each graphical display can be specified in far fewer numbers than are stored in the data file. Thus, the proposal is to install at the central location a web servlet that can extract compact data arrays, of a form dependent on the requested display type, from the stored files and transmit them to a remote client computer program for display.
A client program (WEASEL) and a web servlet (FCSServlet), both written in the Java programming language, were designed to communicate over standard network connections. WEASEL creates familiar numerical and graphical display types and allows the creation of gates from combinations of user-defined regions. FCSServlet selects cells from the data collection under instruction from WEASEL and constructs and transmits a suitable data array. Data compression techniques further reduce transmission times for data arrays that are already much smaller than the data file itself.
For typical data files, network transmission times were reduced more than 700-fold for extraction of 1D histograms, between 18 and 120-fold for 2D histograms and 6-fold for colour-coded dot plots. For each data array transmitted, numerous display formats are possible without further access to the data file. This scheme enables telephone modem access to centrally stored data without restricting the flexibility of display format and also allows comparisons between data from locally and remotely stored files.
