Biology Reference
In-Depth Information
Workflow composition
Web Service Interface
Web Service Interface
Shared
Repository
Workflow
engines
Application
Process Flow Templates
Application
web service
WSproxy
Wfbus
Grid Middleware:
Process & resource management
Grid Middleware:
Data management
Network & Computing Resources
Network & storage Resources
Data Management Stack
Process Management Stack
Fig. 7.3 The architecture of the e-science virtual laboratory developed in the VL-e project.
A service-oriented architecture has been adopted to glue all the components needed to support
the lifecycle of e-Science applications. The components are decomposed into two categories:
components for data management and components for process management
et al. 2001 ; Belloum et al. 2003 ). A PFT is defined by application domain experts;
it captures the expertise and knowledge of the experts and is meant to transfer this
knowledge to other scientists. A PFT provides context-sensitive assistance for novice
users performing complex studies, helping them avoid mistakes and increasing the
efficiency and accuracy of their experiments (Kaletas et al. 2002 ; Frenkel et al. 200 1).
PFTs cover both the experiment design and the dissemination phase defined in
Sect. 7.3 . In the scope of experiment design, PFTs allow domain experts to define
the steps of the experiments, the data structure, and the infrastructure needed to
complete the experiment and how it should be used. PFTs can be seen as a tool to
create templates which determine how experiments should be performed. There are
three basic building blocks of PFTs that contain metadata on:
￿
Objects , where objects can be either physical objects or bulk data in mass
storage,
￿ Manual Operations which are non-computational in nature and can be
performed personally by the scientists,
￿
Executable operations which are specified in a separate specific executable
work fl ow (outside of the PFT).
Using the example of the MACS lab introduced in Sect. 7.2 , we describe how
PFTs can be applied in a real-world scenario. The PFT has been used to describe the
complex flow involved in the data analysis, in this particular case preparation of a
sample, surface analysis, visual inspection and possibly re-analysis. A simplified
version of such a data flow is shown in Fig. 7.4 . Typical steps in a surface-analysis
study are represented by the MACS lab PFT.
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