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Among the conveniences of the Internet is the ability to capture information about events and appointments and plug it directly into your electronic calendar. The ease of feeding and synchronizing personal calendars, and using that data for tasks such as scheduling meetings, is made possible by standards developed over the years that define the data in consistent and predictable ways. Now, magnify that idea of scheduling into the ability to deliver vital resources in large quantities at precise times, with millions of dollars or Euros at stake, and you will need scheduling functions on a grand scale, well beyond the scope of your smartphone calendar. In the past few months, a standard has emerged that defines a framework for this kind of high-powered scheduling, with XML at its core.
That framework is found in the Web Services (WS-) Calendar standard, issued by OASIS in July 2011. WS-Calendar adapts existing scheduling specifications devised for personal use, but designed instead for the hands-off Web services environment needed in high-volume, high-stakes industrial applications.
Driven by smart grids
Driving WS-Calendar are the needs of emerging smart electrical power grids. Smart grids are considered essential for delivering electric power to homes and businesses in times of increasing yet fluctuating demands, use of more renewable power sources, and the need for greater efficiency to lower costs and provide security against terrorists.
Smart grids are envisioned as the interconnections between power generators and consumers, as the grids do today, but adding many more services for business and residential customers. The new grids are expected to schedule delivery of power to meet peak demands, while moving other heavy power uses to less expensive, off-peak periods. Smart grids will also be asked to collect and store power from renewable, but intermittent, sources of power such as wind and solar, while accommodating more reliable, but fossil-fuel based coal and natural gas.
Smart grids are expected to be enormous collectors and processors of data -- much more data than today -- but current power grids, in the U.S. at least, are hardly up to the task. A report issued late last year by a task force at Massachusetts Institute of Technology pointed out that current electrical grids do not have the ability to capture, process, and get actionable information from this flood of data.
WS-Calendar aims to make a start in correcting that problem. The specification was designed with contributions from the U.S. National Institute of Standards and Technology Smart Grid project and North American Energy Standards Board. But the effort attracted interest from more than the electric power industry, getting input from businesses and organizations in fields such as building construction and financial services, in the U.S. (e.g., Trane) and Europe (Siemens AG).
The specification offers a common XML schema and terminology for communicating schedules of related services over time, called a sequence. Sequences are made up of intervals, with units known as durations, defined as the length of time for an interval. The interval`s relation, as it`s called, defines the temporal order of those intervals in a sequence. The times between intervals are called gaps that identify the durations between predecessor and successor intervals.
The scheduling functions defined by WS-Calendar do not operate in a vacuum, of course, but in the context of business services. The standard provides containers, called attachments, for payloads with data representing those services. WS-Calendar does not specify attachments any further than the container, leaving it up to the payloads to conform to the scheduling rules.
Based on personal calendar specifications
WS-Calendar builds on familiar calendaring and scheduling specifications for individuals, which should encourage implementation of the standard. Much of the terminology is taken from the Internet Calendaring and Scheduling Core Object or iCalendar specification, published by the Internet Engineering Task Force (IETF) in 2009.
In August 2011, IETF released an XML format of the iCalendar spec known as XCal, developed by CalConnect, a consortium of groups involved in calendaring and scheduling. CalConnect was represented in WS-Calendar from the outset.
The current WS-Calendar standard covers the information model and XML vocabularies. OASIS`s technical committee is still working on extensions of the document to cover REST and SOAP Web services for calendar updates and synchronization.
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