represented by means of various formats, such as XML or JSON. An appealing type
of application made available through the SmartSensor consists in Web mashups.
Web mashups are ad-hoc Web applications built upon the combination of real-time
information (data, presentation and functionality) from multiple Web sources.
The goal of the Programming and Execution Module (PEM) of SmartSensor is to
allow end users to program Web mashup applications through the composition of a
mixing of public available services and services provided by SmartSensor registered
SIMs. The PEM's programming environment provides a DSL (Domain Specific
Language) specifically tailored for theWSNenvironment, as well as an interpreter for
such DSL. PEM's DSL is an extension of the Enterprise Mashup Markup Language
(EMML). EMML is an open language specification promoted by the Open Mashup
Alliance (OMA) [ 3 , 4 ].
Section 5.1 explaining the concept and the technologies associated with the cre-
ation of mashup applications, showing their main features along with examples of
companies that have successfully used such approach. Next Sect. 5.2 we describe the
architecture and main features of the Programming and Execution Module.
5.2 Web Mashups
Web Mashups are ad-hoc Web applications built upon the combination of real-time
information (data, presentation and functionality) from multiple Web sources. The
term Web Mashup implies easy, fast integration, frequently using open application
programming interfaces (API) and data sources to produce augmented results that
were not necessarily the original reason for producing the raw data [ 4 , 5 ]. Data and
presentation information typically comes in formats such as Rich Site Summary
(RSS) or Atom feeds, different XML based formats, or as HTML, or other graphi-
cal elements. Application functionality can come from any Web accessible API as,
can be used to combine data, functionality, and presentation to create the Mashup
applications [ 1 , 6 ].
Developers are currently creating a plethora of mashups covering a wide range of
domains, from esoteric mashups that record the location and availability of rare gam-
ing consoles to those that create Sudoku games from Flickr photos. However, there
are also more generally useful mashups, such as those offering weather information
and mapping services.
For enterprises, the Web mashup paradigm can be used as a simple and cheap
way to access data and combine different data sources, encouraging innovation by
allowing new ideas to be tested, refined and improved at very low cost. One of
the first organizations to leverage mashup technology for immediate results was the
JP Morgan Chase [ 3 ]. This company employed a rudimentary mashup technology
to integrate real-time data on commodity performance within analytical tools that
allowed security traders to monitor up to 500 portfolios at once. This mashup was
named Trading Algorithm Optimizer (TAO) [ 3 ]. Another example of Web applica-