Table of Contents

Introduction

The NCI-supported caBIG program is facing a major expansion of its mission and of the community of stakeholders that it must engage. The success of the program to date has been widely recognized by numerous thought leaders, technology innovators, and program managers in the fields of biomedical computing and health information technology.  These leaders have been influenced by both the technological sophistication and the open community processes of the caBIG program, and are seeking to adapt caBIG to meet the much broader agenda of health care information management, sharing, and integration across institutions, communities of practice, and patients.

As a means towards engaging this larger community and contributing to the creation of solutions for its needs, the BIG Health Consortium was formed, a non-governmental organization that is affiliated with caBIG, but which has a complementary agenda that is focused on enabling the integration of research, care delivery, and patient-driven decision making in practical ways.  As a consequence, the institutional stakeholders associated with BIG Health Consortium extend well beyond the cancer centers, universities, and cooperative groups that make up the core NCI-funded constituencies that have participated in caBIG since its original incarnation.  The extended community thus goes beyond what is considered caBIG-proper today, and includes groups that are not yet connected to caGrid.

Background

The primary goal for this Architecture, Development, and Deployment of a Knowledge Repository and Service is to address the needs of this extended community for a scalable, decentralized infrastructure for managing and disseminating operational metadata and information models, and their associated semantic constructs.  The vision for the project is to re-imagine the caBIG technology environment as a more open and more readily extensible framework, one that can grow with less dependency on the centralized processes and systems that are manifest in the first generation of caBIG technology.  In particular, the role of the central metadata registry, the caDSR, must be redefined as a federation of metadata registries that can be instantiated and plugged into the caBIG grid or an extended community "cloud" by any qualified entity. 

The caDSR has a suite of tools and APIs that support workflows for metadata development, browsing and retrieval.  In addition, the caDSR has been adapted to support the UML model-driven development paradigm adopted by caBIG.  UML-defined information models such as those from the BRIDG project, caArray, caTissue, and others are each registered in the caDSR through conversion of the model elements into ISO11179 metadata constructs.  This functionality, and the workflows that it supports, has evolved over an 8-year period and is now quite mature.  It satisfies the current requirements for semantic representation in the current caBIG developer and user community, but it is ill-suited to serve the new requirements for decentralization and indefinite scalability in the broader health care community. The goal of this program is therefore to harvest and recycle the best elements of the first generation of caBIG metadata infrastructure, and to then incorporate those elements into a redesigned and modernized technology stack that is engineered from the start to support a federated deployment topology with far less centralized administration.

Scope

This program calls for the design and implementation of a metadata registry and model repository that can be instantiated in multiple physical locations in a federated manner, and which supports the caBIG and BIG Health community needs for operational semantic metadata management and integration.  The program must provide a number of capabilities and services:

• Design and implementation of the ISO 11179 Edition 3 standard in a metadata repository (MDR) architecture.  The current caDSR implements Edition 2 of the standard, and the NCI has published a gap analysis between caDSR and ISO 11179 Edition 3 that will inform this effort.
• Implementation of an information Model Repository that supports caBIG/BIG Health information model registration and alignment of models with ISO 11179 metadata elements. 
• Extension of the metadata standard and associated workflow tools to cleanly accommodate ISO 21090 data types.   Some work has been done to represent ISO 21090 in caDSR, but a number of gaps remain.
• Service-oriented programming interfaces that can be registered and exposed in caGrid, and which are compliant with emerging W3C standards. 
• Tools to support an updated and revised semantic integration workflow that enables decentralized and localized additions of models and data elements. 
• Transformation services that can traverse and extract the various semantic metadata constructs, including information models, data elements, and associated Description Logic (DL)-based terminologies.  The preferred or native format for the representations should be available through these services rather than forcing users to interpret one format through the lens of another.  Moreover, higher level services that cater to use cases for run-time semantics of consumer systems will need to be defined and implemented. 
• Migration path from the current caDSR and associated tooling to the new MDR and Model Repository architecture.

Users and Characteristics

Related Documentation

The following is a list of documents that provide background material, requirements, and related topics:

• Con Ops Supplemental Page for Requirements Gathering: https://wiki.nci.nih.gov/display/VCDE/Supplemental+Page+for+Requirements+Gathering 
• Semantic Requirements Forum: https://cabig-kc.nci.nih.gov/Vocab/forums/viewforum.php?f=34
• Con Ops Stakeholders: https://cabig-kc.nci.nih.gov/Vocab/KC/index.php/SI_Conop_Stakeholders
• Con Ops Requirements: https://wiki.nci.nih.gov/display/VCDE/Requirements+Questionnaires
• Con Ops Use Cases: https://wiki.nci.nih.gov/display/VCDE/Use+Cases+for+Semantic+Requirements

Terms & Definitions

Assumptions and Dependencies

Usability

The user interface shall be designed for ease-of-use by the designated end-users, shall use terms common to the user's normal business environment, and shall require little to no additional training on the system. Drop down menus, Google-like searches, and tooltips should be used wherever appropriate.

Accessibility

The user interface should be accessible via a web browser.

General Assumptions

Following is a list of basic assumptions:

• Federated Discovery Services: Knowledge Repository Services will be distributable and discoverable in a federated manner
• Security Considerations: services and underlying data will be secured using the caBIG security architecture
• Subscriptions/Notifications: services requiring subscription and notification functionality will be enabled by the caBIG pub/sub architecture
• ISO 11179 Ed 3: the Knowledge Repository will comply with ISO 11179 Ed 3 specifications
• Ability to have non-administered items: the Knowledge Repository will provide for non-administered items in the ISO 11179 notion
• Duplication/identification: in compliance with the Federated Discovery Services assumption, reference of data, data duplication, and unique identification of data will be handled

Dependencies

TBD

Functional Requirements

Model Services

Some basic description of model services.

Metadata Services

Some basic description of metadata services.

Non-functional Requirements

Performance

Performance refers to the qualitative or quantitative measure of how well a system reacts in a user workflow.  This can be measured in time from a user or system perspective, as well as the amount of resources (CPU, memory, etc.) that software must consume to complete a task.

Auditing, Logging, and Provenance

Auditing, logging, and provenance is the process of recording events in an automated and/or manual way within a certain scope in order to provide an audit trail that can be used to understand the activity of the system and/or to diagnose problems.

Fault Handling

Fault handling is a mechanism designed to handle the occurrence of exceptions, special conditions that change the normal flow of software or user execution.

Quality of Service

Quality of service is the ability to provide sufficient uptime and availability of software to guarantee a certain level of performance to access and data flow.

Usability

In design, Usability is the study of the ease with which people can employ a particular tool or other human-made object in order to achieve a particular goal.

Security

Security is the protecting of information and information systems from unauthorized access, use, disclosure, disruption, modification or destruction.

Portability

Portability is the software codebase feature to be able to reuse the existing code instead of creating new code when moving software from an environment to another. The prerequirement for portability is the generalized abstraction between the application logic and system interfaces.