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Overview of the Object Modeling System

The Four OMS Platforms

The Object Modeling System (OMS) is a framework and development kit for designing, building, validating, and deploying agro-environmental models. It contains four platforms: (1) model development, (2) model deployment (cloud services), (3) data provisioning, and (4) knowledge base (component repository). This training course is focused on the model development platform. The other three platforms will be covered in companion courses.



With OMS, modelers can:
  • Create science components without framework boilerplate intruding on the source code
  • Add simple annotations to components to enable linkage into compound components and models
  • Apply a unit test harness to verify component function and performance
  • Obtain previously developed components from the OMS component library
  • Connect components developed in Java, Fortran, C, and other languages to create models
  • Automatically generate component and model documentation, always in sync with source code
  • Create model simulations for verification testing, calibration, validation, and analysis, including:
    • LUCA calibration (shuffled complex evolution)
    • DDS (Dynamically Dimensional Search) calibration
    • FAST (extended Fourier Amplitude Sensitivity Test) sensitivity analysis
    • Morris sensitivity analysis
    • Sobol sensitivity analysis
    • NSGA (Non-Dominated Sorting Genetic Algorithm) uncertainty analysis
    • GLUE (Generalized Likelihood Uncertainty Estimation)
    • Bayesian Monte Carlo uncertainty analysis.

Platform 1 - Model Development

This platform is the focus of this training workshop, covered in the following sections of this workbook.

Platform 2 - Data Provisioning

This platform provides a common architecture for provisioning data to OMS models and model services. The first implementation of the platform is supporting the deployment of the Revised Universal Soil Loss Equation (RUSLE2) model service. An architectural overview is provided in the following diagram:

.....Data Services Diagram

Platform 3 - Cloud Services

This platform supports the deployment of models as services in a cloud computing infrastructure. The first implementation of the platform is the RUSLE2 model service.

.....Cloud Services Architecture Diagram

.....RUSLE2 Model Service Diagram

Platform 4 - Knowledge Base

This platform currently consists of the You must login to see this link. Register now, if you have no user account yet.. The platform will expand to include an OMS ontology and knowledge base to assist in component selection during model development. An example query could be: find science components having unput variables A and B and outputs of C dand D and keywords solar radiation. The component finder would find and display the best matches.

The knowledge base platform also will support concept models created by OMS modeling communities. Program delivery agencies often have standardized concepts of land areas and landscape features, and expressing them in an ontology and knowledge base helps to ensure the integrity of an information system built around these core concepts. An ontology rendered in Web Ontology Language (OWL) can provide the conceptual basis for creating entity-relationship models and resulting databases, universal modeling language (UML) content to guide programming, and business process execution language (BPEL) supporting automated workflows.

The OMS Model Development Platform in a Little More Detail

The high-level architecture of the OMS model development platform is shown below. The platform contains re-usable system components for model control (time, space, phase, input/output), components for model calibration, analysis, and pre- and post-processing visualization.



A typical case agricultural or environmental simulation model starts with time, containing time steps (iterations). The land area being analyzed will contain one to many land units (also considered iterations because data may flow from one land unit to another). Science components run within each land unit within each time step. With each time step, climate and management data are inputs to science components. Output from science components in the previous time step also may be inputs to components in the next time step. Data can flow from one time step to the next, and can flow among among components within and across land units, across time steps. Time and space control usually are integral components of the model.

The CSMLite model, the example featured in this workshop, introduces another type of model control: component phases. This can be considered another type of iteration. With CSMLite, the rate calculation and data integration phases of each component run within a time step. OMS provides underlying system components supporting different types of iteration control.

The training workshop does not examine the underlying OMS application programming interface (API) providing the system components and tools that make up the platform. Those wanting to "look under the covers" can do so via the OMS JavaDocs, also available as a link on the OMS Javaforge home page.

The reason for not digging into the OMS API is that the system components and tools manifest through the OMS domain specific language (DSL), a simplified and brief syntax designed for testing and calibrating models, running simulations, visualizing and analyzing output.

The Object Modeling System Laboratory (OMSLab)

Responding to increased interest in OMS, the CSU Department of Civil and Environmental Engineering has established the OMS Laboratory (OMSLab) to support the modeling communities using OMS, facilitate interaction among communities, and coordinate enhancements to the framework. A primary goal is to help increase and optimize science-based decision making for agricultural and natural resource management.

OMSLab Responsibilities

OMSLab provides the means to collaboratively:
  • Maintain and enhance the OMS framework
  • Conduct research to develop new modeling technologies
  • Contribute to and maintain an open source repository of models, components, data, and metadata including a knowledge base to understand and access the content of the repository
  • Apply quality assurance to model components
  • Deploy models as services on operational platforms
  • Develop data and data access services for OMS models and model services
  • Develop education and training materials
  • Leverage and exchange knowledge and expertise across modeling communities, including an OMS Users Conference.

Products and Services

The following products and services are available through OMSLab:
  • OMS framework components and simulation console
  • Models and components from the OMS library
  • Soil, climate, and management data access
  • Training workshops
  • Technical support in the use of OMS
  • Consultation in the use of OMS models
  • Component and model design and programming
  • Business application x model integration
  • Model calibration and validation
  • Model and data service hosting

The OMS framework, console, model components and models can be freely downloaded through https://oms.javaforge.com.

Other services can be obtained through contracts or agreements with OMSLab involving funding or in-kind contribution of resources among members. OMSLab provides a place for modeling communities to interact and collaborate on activities of mutual interest.

Private sector members also can add value to open source OMS content to create commercial products and services for their customer segments.

Membership

Organizations can become members of OMSLab through cooperative agreements or memorandums of understanding. The core members of CSU, ARS, and NRCS provide representatives to the OMSLab Advisory Board. As interest in OMS grows, other member organizations may be invited to participate on the Advisory Board. OMSLab by-laws provide for technical committees of representatives of OMSLab members.

For additional information and inquiries about membership and participation in OMSLab, please contact:


    Jack R. Carlson, Director (Jack.Carlson@colostate.edu)
        -or-
    George H. Leavesley, Senior Research Scientist (GHLeaves@colostate.edu)

    Object Modeling System Laboratory
    Department of Civil and Environmental Engineering
    312 General Services Building
    Colorado State University
    Fort Collins, Colroado  80523

    Phone:  970-491-2753
    Fax:  970-491-7626
    Web Site:  http://omslab.colostate.edu (pending)