Global Positioning System Reference
In-Depth Information
Kepler
Kepler
2
(Ludäscher et al. 2006) is a modeling, execution, and deployment
framework for scientifi c workfl ows across different domains. Kepler is used
in various kinds of projects such as biological sciences, DNA sequences,
and geosciences and earth observation among others.
3
The main components in Kepler are
directors
,
actors
, and
parameters
as
well as
channels
and
ports
.
4
A scientifi c workfl ow in Kepler consists of a
combination of actors. An actor can be regarded as an analytical task. Kepler
follows an actor-oriented programming interface (Ludäscher et al. 2006)
as a methodology to turn analytical tasks into Kepler-compliant actors.
That is, an actor provides a customized interface to support distinct types
of processing tasks such as fi le management actors, control actors, display
actors, GIS actors, and so forth, which come pre-defi ned when installing
the Kepler framework. Like a function signature or method, each actor has
parameters that allow users to customize the behavior of a particular kind of
actor. For instance, a pre-defi ned fi le management actor may be customized
to locate and unzip a given data fi le in a specifi c format.
Data communication between actors is carried out via ports. Each
actor in a Kepler workfl ow can expose one or more ports used to consume
(input ports) or produce (output ports) data in order to communicate with
other actors within the workfl ow. The data-fl ow connection between one
actor port and another actor port is called a channel. Finally, a director is
meant to control the execution of a workfl ow. Every workfl ow must have
a director that defi nes whether the set of actors are executed for example
in sequence or in parallel. Roughly speaking, directors specify the control
fl ow of a scientifi c workfl ow.
The ability of reusing a part of or an entire workfl ow is managed via a
specifi c type of actors.
Composite actors
, or sub-workfl ows, wrap some atomic
actors for performing more elaborated operations. As an entire workfl ow
can be a composite actor, it can be re-used by other Kepler workfl ows.
The Kepler framework also contains a graphical user interface and an
execution engine to help scientists to edit, manage and execute scientifi c
workfl ows. Scientists can create their own scientifi c workfl ows by simply
dragging and dropping actors onto a design area, where actors can be
customized, combined and executed.
http://kepler-project.org
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3
https://kepler-project.org/users/projects-using-kepler
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Getting Started Guide: https://kepler-project.org/users/documentation
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