ARGOS: Dynamic Composition of Web Services for Goods Movement Analysis and Planning

Project Description

Argos is a flexible data query and analysis system based on the web services paradigm. As an application domain we will examine several goods movement planning problems and their effects on spatial urban structure.

Many scientific problems can be modeled as a workflow that includes information gathering and processing operations. We propose a unifying framework where these operations are modeled as web services and the scientific workflows as compositions of web services. Argos focuses on automatic composition of web services workflows. Our approach consists on giving precise logical descriptions to the inputs and outputs of each web service based on an ontology of the application domain. We do not assume that the inputs and outputs are simple types, such as strings or numbers, but that the services process complex types, in particular, relations. Reasoning with these relational descriptions allows the Argos planner to automatically compose a workflow in response to a user data request, including inserting adaptor services that transform the output of one service to the input require by another.

We use Argos in a metropolitan transportation planning scenario in consultation with our advisory team, that includes government practitioners from the California Department of Transportation, the Los Angeles County Metropolitan Transportation Authority, the San Bernardino Associated Governments, the Southern California Association of Governments, the Port of Long Beach, and others. The scenario analysis allows evaluation of Argos in terms of its expressiveness, utility as a transportation planning tool, and ease of use by developers and practitioners.

Argos in funded by the National Science Foundation, Digital Government Research Program .

Participants

Argos is a multidisciplinary project between the School of Policy, Planning, and Development (SPPD) and the Information Sciences Institute (ISI) of the University of Southern California (USC) under the auspices of the Digital Government Research Center.

Alumni

Argos Twiki (restricted access)

Software Demonstrations

Automatic Service Composition with Relational Descriptions

We developed a planner to automatically compose data processing workflows in response to user's data requests. We use PowerLoom to represent data sources and operations and to reason about the relationship between inputs and outputs of services. The planner automatically inserts adaptor services as necessary. The dg.o2007 paper explains some of the details. Some examples of workflows automatically generated by the planner:

Product Conversion Web Service

A situation that occurs repeatedly when integrating economic data from different sources is the need to translate data expressed in one product classification into another. Economic data is reported in a variety of classifications, including the Standard Classification of Transported Goods (SCTG), the Standard Industrial Classification (SIC), the North American Industry Classification System (NAICS), among many others. Unfortunately, there is no shortage of standard classifications. Thus, we have developed a Product Conversion Web Service that automates the translation of data categorized according to different industry/product classifications. We provide two ways of accessing the Product Conversion service:

Please send an email to if you use this web service, and/or you have comments.

The bridge tables used in the web service were developed by JiYoung Park (jiyoungp@usc.edu) and LanLan Wang (lanlanwa@gmail.com). Please contact them if you have questions on their estimation methodology.

Automatic Composition of Aggregation Workflows

We built two demos that show our automatic composition of aggregation workflows as described in this poster and in the dg.o2005 paper. We used RDF as our representation language and Triple as our reasoning engine: These demos were presented at the National Conference on Digital Government Research (dg.o2005).

BPEL4WS workflow

The demo shows a portion of the Argos workflow that estimates the commodity imports and exports for the Southern California Association of Governments (SCAG) area based on Waterborne Commerce of the United States (WCUS) data and Port of Long Beach statistics. The demo shows a BPEL4WS workflow where the data sources and the processing steps are implemented as web services. It was presented at the National Conference on Digital Government Research (dg.o2004).

Launch the dg.o2004 demo. Click on the ovals to see intermediate data produced at different steps of the workflow. You can also see the data in its native RDF representation.

The demo is described in more detail in this poster and the paper Argos: An Ontology and Web Service Composition Infrastructure for Goods Movement Analysis below.

[Note: The links above point to a cached version of the dg.o2004 demo.]

Publications

Presentations