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Improving the Quality of Environmental Information Systems and Services
Reusable Component Services (RCS) provides a central point of access to a broad range of IT resources, components and services used in various EPA and partner systems. It enables reuse of these resources, which helps reduce cost, speed development, and produce higher quality systems and applications.
RCS allows users to:
- Catalog reusable information assets for EPA and its partners
- Load metadata about assets
- Harvest metadata from other Agency registries and repositories
- Relate services, data assets, and the systems and applications they are used in
- Access a single interface through which users can search for all resources regardless of their type and location
By enabling and promoting reusability, RCS results in the development of applications that:
- Conform to standards
- Are of higher quality
- Are produced at a reduced cost
- Are produced more quickly
RCS is a registry of reusable resources of many types. The resources are used to build, document, and test systems and applications. Furthermore, as they are reusable, they will be of value to system developers and architects.Reusable Component Services
RCS stores metadata about resources in order to allow for their discovery. In that capacity, it:
- Stores metadata about services and resources
- Provides links to existing repositories
Web Services - metadata about automated services that can be used and shared by software applications
XML Schema - schema used in data flows for EPA and the Exchange Network
Shared Schema Components - schema pieces and a workbench to assemble schema
Blocks of Code - code blocks for use in building applications
Data models and Data Dictionaries - metadata about databases and application models
Templates - various templates, including web and portal templates
Code Sets and Data Sets - Code sets and data sets used by applications
Software Tools - information about available software for sharing
Reference Library - best practices, lessons learned, solutions, technologies, etc.
Function of RCS
Discover - search and browse resources and services
Access - view and download resources and services
Register - add entries for resources and services with metadata to aid discovery
Store – add a resource or service to RCS if it's not currently in any repository
Subscribe - receive notifications about new or updated services resources
Rate – provide feedback on quality and usability of a resource
Collaborate - exchange information; e.g., questions, answers, needs, and solutions
- What is a
Some resources may be ready to integrate seamlessly into a system (e.g., Web services). Others may constitute blocks (e.g., code blocks) used to build other components. Still others may be used as modifiable templates (e.g., data dictionaries, data models) to design or build an application. It is acceptable to register a resource that is part of a process and that is able, by itself, to perform a function (e.g., XML schema).
The Vision-and-Scope workshop and interviews conducted in the third quarter of 2007 produced the following vision statement:
The purpose of the RCS is to provide a clearinghouse of information about components, services, technologies, and solutions in a collaborative workspace so that application and database development, and architecture are performed in an effective and efficient manner, capitalizing on lessons learned from others and promoting re-use of previous work.
The implementation of a Service Oriented Architecture (SOA) at EPA requires a vehicle of outreach and discovery for a multitude of reusable system components. EPA and the Exchange Network (EN) have a vision of a master catalog, or super-registry, that would provide a one-stop place to discover components of many different types, hosted and/or managed by many different organizations.
In addition, the Data Standards Branch (DSB) within EPA’s Office of Environmental Information (OEI) has been involved in the setup and maintenance of registries and in the support of enterprise architecture, terminology services, and substance services such as the XML Registry used by the EN. The RCS is the direct result of developers and users, both from program offices and the EN, approaching DSB with inquiries and requests for the location of registries for many types of objects, services, and components, such as data models, code sets, web services, and pieces of code.
The Agency-wide interest raised by the RCS and the planned alignment with the Agency’s Enterprise Architecture has positioned the RCS to become the Service Catalog for the Agency’s SOA Initiative being developed by the Information Exchange and Services Division.
How does RCS Contribute to Quality Information?
The purpose of the RCS is to enable reusability of components and services. When components and services are reused, defects are detected and corrected early in the life of the components, and thus the quality of the components and services improve. In addition, pressure from multiple users forces upgrading of the components to make them more effective and more efficient.
Improved, more efficient, error-free components are quality components, and quality components result in higher quality systems. Furthermore, ready-to-use components need not to be re-developed, and, therefore, reduce the duration of the system development cycle. This, in turn, improves timeliness of implementation and reduces costs allowing a system or module to be fielded faster so users can take advantage of the functions provided.
How is the Quality of the Information in RCS Ensured?
RCS can contribute to quality only if it helps with the discovery of quality components and if it provides quality instructions on how to use those components.
Each component in RCS will have enough associated metadata to show the context and conditions of when and where it should be used and when and where it should not be used. In addition, each component will have associated instructions to enable the proper, efficient, consistent, and effective use of the component.
The quality of the components in the RCS will be assured by an effective workflow and a rigorous approval process. The workflow will include stewardship and oversight by technical staff. This process will result in components and systems with fewer defects and a higher re-usability.
- Registration and discovery for business services, data services and technology services, including Web services
- Composition of services through the use of relationships
- Linking of services to related systems, applications, data sets, etc.
- A repository for service-level agreements
- A place to store and register policies and rules
- Registration of resources of many types, among them: systems and applications, XML schema, Web services and many others.
- Support of standards through sharing and reuse of components
- Classification schemes (i.e., taxonomies) that include EPA’s Business Reference Model and EPA’s Service Reference Model
- Metadata attached to every resource
- Relationships between resources
- Documentation for all resources and services
- A repository for system administration and user manuals
- Search and discovery mechanisms for all types of resources, regardless of their location
RCS supports the Exchange Network by:
- Making services and resources available for application development
- Registering data flows, their schema and services
- Supporting data flow development
- Supporting a schema report card and other tools
- Providing a collaborative place for sharing documents, discussions, plans, lessons learned and best practices
The similarity of applications required by the states and tribes for their own systems and for reporting to the federal government provides a unique opportunity for sharing. The magnitude of the savings in time and money, as well as the increase in application quality, is especially large.