Because the LHD project has been operating with the cooperation of many institutes in Japan, the remote participation facilities play an important role. Therefore, NIFS has been introducing these facilities to its remote participants. Because the authors regard Web services as essential tools for the current Internet communication, Web services for remote participation have been developed. However, because these services are dispersed among several servers in NIFS, users cannot find the required services easily. Therefore, the authors developed a portal Web server to list the existing and new Web services for the LHD experiment. The server provides services such as summary graph, plasma movie of the last plasma discharge, daily experiment logs, and daily experimental schedules. One of the most important information from these services is the summary graph. Usually, the plasma discharges of the LHD experiment are executed every three minutes. Between the discharges, the summary graph of the last plasma discharge is displayed on the front screen in the control room soon after the discharge is complete. The graph is useful in evaluating the last discharge, which is important information for determining the subsequent experiment schedule. Therefore, it is required to display the summary graph, which plots more than 10 data diagnostics, as soon as possible. On the other hand, the data-appearance time varies from one diagnostic to another. To display the graph faster, the new system retrieves the data asynchronously; several data retrieval processes work simultaneously, and the system plots the data all at once.
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