Information Technology Reference
In-Depth Information
implemented to ease building and running caGrid workflows. It pro-
vides users with support for various phases in using workflows: service
discovery, composition and orchestration, data access, and secure
service invocation, which have been identified by the caGrid commu-
nity as challenging tasks in a multi-institutional and cross-discipline
domain.
1.
Service discovery
—where to find services that are relevant to
the scientific investigation of a user.
2.
Data access
—what kind of data (data types) can be obtained
from a given service and how to transfer data from and to it.
3.
Service interaction
—how to invoke services and maintain
session information in multistep interactions.
4.
Security enforcement
—how to enforce authentication and
authorization in service invocations and privacy and integrity
in data transfers.
5.
Knowledge sharing
—how to share workflows with the com-
munity, how to find out what other researchers in the field are
doing, and how to leverage the best practice from them.
We have followed two principles in the design and development of
the toolkit. First, instead of reinventing the wheel, we have adopted the
software tools that are widely used by the life science community,
namely Taverna and myExperiment [186]. We have improved these
tools by offering more advanced features in the form of plug-ins that
make caGrid infrastructure accessible from Taverna. Second, we have
worked closely with scientists from caBIG to fulfill their needs, while
making our tool applicable to any user community that embraces a
similar service infrastructure.
Implementation of caGrid Workflow Toolkit
Figure 7.4 shows the architecture of the caGrid Workflow Toolkit.
The solid rectangle in the middle consists of the five components that
are extensions to Taverna. The components in dashed rectangles are
modules in caGrid infrastructure and myExperiment. They are num-
bered in accordance with the toolkit's components to prescribe the
interactions in between.
Service discovery
component
locates the
