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CRANFIELD UNIVERSITY Eleni Anthippi Chatzimichali ...

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Google Chart Tools (https://developers.google.com/chart/). The users can create<br />

dynamic, interactive, feature-rich web-based graphs via R, without uploading their<br />

data directly to Google. However, the package does have certain limitations; in order<br />

to visualise the graphs in the browser, there is a need for Internet connection in<br />

addition to the installation of the Flash plug-in. Another package, iPlots (Urbanek and<br />

Theus, 2003) is a powerful R package for the creation of interactive graphics that<br />

offers features such as querying, linked highlighting, and colour brushing, among<br />

others. Even so, the iPlots package runs as a standalone graphical user interface<br />

(GUI) within the R console, and cannot be embedded within any other project or<br />

interface. In addition, the core of the package is written in Java, hence a fully<br />

working Java installation on the local machine is expected.<br />

6.2.5 Constructing a web interface for demonstrative purposes<br />

As part of this project, a web interface has been constructed for demonstrative<br />

purposes as the front-end of the multivariate analysis pipeline. This approach attempts<br />

to evaluate whether the results of the analyses can be directly embedded within any<br />

HTML page and/or web project. As presented in Section 6.2.1, the web interface was<br />

chiefly built by using two powerful JavaScript-based technologies; namely, jQuery<br />

and AJAX. In this work, AJAX requests are triggered from the web front-end, more<br />

specifically from jQuery scripts embedded within static HTML pages, towards<br />

specific Perl files located at the server-side. These requests may also carry additional<br />

information such as associated data and input parameters. Subsequently, the Perl<br />

scripts execute the relevant R scripts, also stored on the web server, after passing<br />

these parameters. Once the R script terminates the execution of the scripts, it returns<br />

the output of the analyses (calculation results, plots, files, et al.) back to Perl. Finally,<br />

Perl sends an asynchronous AJAX response along with the requested results back to<br />

the original client-based script. The web interface is partially updated and the output<br />

from R is displayed to the user, without the need of reloading the entire page. Due to<br />

AJAX and its asynchronous functionality, the exchange of requests, responses and<br />

data is performed within seconds.<br />

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