Related Work - User-Level Workflow Design: A Bioinformatics Perspective - page 163

takes place in a graphical user interface that provides a number of precon-
figured local tasks and configurable Web service clients. What is more, the
Kepler Analytical Component Repository [11] maintains a collection of ana-
lytical services that can be downloaded and imported into Kepler.
Taverna
Taverna [134] is a workflow environment for the life sciences that has been
developed in the scope of myGrid [309], a UK initiative focusing on eScience.
Not least because it is strongly supported by the UK life science community,
it is currently the probably most popular workflow system in bioinformat-
ics. Consequently, Taverna has been used within a large number of projects,
predominantly in bioinformatics (cf., e.g., [184, 185, 195]).
Taverna provides a simple, graphical user interface for building and ex-
ecuting workflows. In addition to a small set of locally operating workflow
building blocks for common tasks, Taverna integrates bioinformatics web ser-
vices and other kinds of remotely available tools, explicitly following the open-
world service assumption (cf. Section 1.1.3). Most notably, Taverna includes
comprehensive mechanisms for the automatic discovery of web services for
bioinformatics (browsing, e.g., the BioMoby registries and EBI's SoapLab),
which makes it very convenient to use for workflow designers that are not
willing to or not capable of integrating the services themselves.
At this point also the myExperiment project [113] of the myGrid initia-
tive should be mentioned, which aims at bringing the Web 2.0 spirit into the
life science community. The platform enables researchers to publish, share,
find, and download workflows, with the aim of making the re-use of existing
workflows as easy as possible. They can furthermore tag, rate, discuss and
comment in silico experiments, create and join special interest groups, and
connect with people. At present, most workflows that are available in myEx-
periment are in fact Taverna workflows (cf., e.g., [189]), but the platform is
in principle open to any other workflow format.
Taverna with SADI Plugin
The SADI plugin [344] for Taverna (cf. Section 8.1.2) extends the workbench
by functionality for interactive service discovery: It makes it possible to search
the SADI registry (see above) for services that consume the data type that
is the output of an existing workflow node. However, although the SADI
plugin provides means for semantically guided discovery of matching services
within Taverna, it does not bring the full power of the SADI system into the
workbench.
Note that the UK eScience initiative myGrid [309], where Taverna orig-
inated, has also investigated the use of Semantic Web standards for their
projects [190] and for instance developed the myGrid Ontology for facilitat-
ing bioinformatics service discovery [347] . However, to date they have not
visibly been applied for semantics-based, automatic workflow composition.