The
conversion of gigabytes of satellite data into usable Ecocasts can be
computationally expensive and require hundreds of hours. To automate
and streamline the process, the Ecocast archicture includes IMAGEbot, a
state of the art planning and scheduling agent deveoped at NASA Ames
Research Center. IMAGEbot is softbot designed for data processing
tasks, such as image processing, text processing and document
conversion. These tasks require the softbot to reason about the
structure and information content of data files and to construct
dataflow programs that pipe multiple data-processing commands together.
Planner-based Softbots IMAGEbot
is the planning engine in the Ecocast framework. Given the large
volumes of data, the multiple data sources available for each variable,
and finite compute resources, optimization of data processing plans is
critical to our ability to rapidly convert data into a useful format.
A softbot
is a software robot, aka a software agent, that acts on behalf of user.
A planner-based softbot is a softbot that recieves user goals and uses
an AI planner to figure out how to achieve those goals given the tools
and resources available to it. Such tools can include any programs or
online resources that would be available to a user. Since these tools
were designed for humans to use and not for softbots, "teaching"
softbots how to cope with user interfaces designed for humans has
become a significant research topic in its own right. For example,
there has been substantial work in learning programs (or "wrappers") to
extract information from HTML documents, a problem known as wrapper
induction.
Typical softbot tasks are finding
information, such as phone numbers or movie listings, managing
appointments, online shopping and making airline reservations. Most of
the work has been in the area of finding information on the Web. Since
almost all of the web sites of interest are really just front-ends to
databases, This problem can be solved by a combination of wrapper
induction and database query planning (look here
for more information). In such tasks, the source data (HTML documents)
are not themselves of interest. All of the relevant information can be
represented using SQL or datalog and subsequent processing of the data
consists of standard database operations.
However,
there are many tasks, such as image processing, where neither the
source data nor the desired data products are conveniently represented
as tables. Rather than posing a query such as "tell me the temperature
of every city in the US," it is much more natural to ask for a map, in
which different temperatures are represented as different colors. The
source data may be a grid representing the temperature at each grid
point as a floating point value. Achieving the goal may involve
changing the file format of the input (converting the floating point
values into pixel values), combining files (from multiple small "tiles"
into a "mosaic" representing a larger region), changing the resolution,
thresholding the result to map temperature ranges into discrete color
bands and superimposing the color bands on a line map of the states.
IMAGEbot IMAGEbot
is softbot designed for data processing tasks, such as image
processing, text processing and document conversion. These tasks
require the softbot to reason about the structure and information
content of data files and to construct dataflow programs that pipe
multiple data-processing commands together. IMAGEbot uses an expressive
language, called the Data Processing Action Description Language
(DPADL), to represent data and the commands that act on data. DPADL
descriptions of data goals and source data specify both the information
content of the data and how the information is encoded in the structure
of the data. These descriptions are sufficiently detailed to allow
IMAGEbot to extract the information from the data (that is, they
provide the same level of detail as a wrapper), but their primary
purpose is to allow IMAGEbot to reason about the consequences of
chaining together arbitrary data-processing actions. IMAGEbot will
generate descriptions of every data file it produces, and can even
generate descriptions of files produced by other applications or users,
provided it knows what command sequence was used to produce the files
and it has descriptions of the commands and the input data. These
semantic and syntactic descriptions of secondary data products can be
stored in a database to facilitate later searches or data mining.
The
IMAGEbot planner is a heuristic-search constraint-based planner
specialized for planning in the presence of incomplete information and
very large universes (i.e., a lot of files). The constraint network is
taken from the EUROPA planner, also developed at NASA Ames. The
softbot's knowledge about the world -- what files exist and what
information they contain -- is stored in a PostgreSQL database.
Publications Please see the IMAGEbot site for a list of publications.
Contacts For more information about IMAGEbot or the DoPPLER Planner, please contact
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