1. National Virtual Pointer System (NVPS)
Global Justice XML Data Model Users Conference
June 9, 2005
Atlanta, GA

2. Presenters Brian Dawson Bill Edgin Carl Nelson Kate Silhol
Systems Manager, Midwest HIDTA
Bill Edgin
Senior Principal Consultant, Drug Enforcement Administration
Carl Nelson
Lead Developer, RISS Applications Development Group
Kate Silhol
Senior Software Engineer, NLETS

3. What Is the National Virtual Pointer System?
XML and Web Service based system connecting Federal, State, and Local, & Tribal agency target deconfliction systems
Built on GJXDM 3.0 prerelease, to be updated to during Fiscal Year 2005
Matches return officer contact information
Goal of the system: Put officers in contact with each other

4. Current Participants DEA (NDPIX)
HIDTA program (Appalachia, Chicago, Gulf Coast, Midwest, New England, South Florida, South Texas)
Missouri State Highway Patrol (MoSPIN)
NLETS
RISS (RISSNET)

5. System Architecture No direct communication between systems
Systems connect only to NVPS Message Hub
Hub validates and routes data
Networks involved:
RISSNET: Provider to HIDTAs and MoSPIN, host of NVPS Message Hub
NLETS: Provider to NDPIX and able to provide for other NLETS users
USDOJ: Provider to NDPIX

6. Message Formats & GJXDM Usage
NVPS Message Format: Built to GJXDM 3.0 Prerelease, to be updated to 3.0.3
NLETS Message Format: Currently uses NLETS’ pre-GJXDM format, to be updated to NLETS’ GJXDM-compliant format
NDPIX Message Format: Text-based parsed format

7. XML Format Development
Identification of Data Elements
Policy & Legal Requirements
System commonality
Identification of most valuable data elements to an end user
System Requirements & Header Information
Routing
Tracking
Identification

8. XML Format Development
Tools Used:
GJXDM Wayfarer
XML Spy
Microsoft Visual Studio

9. Problems Encountered During XML Format Development
“Moving Target”: GJXDM 3.0 prerelease
Lack of commonality of code values between systems caused some required elements to become optional!
No Subschema Generation Tool—manual process introduces possibility of errors
Few guidelines or best practices for GJXDM at development time
Use of namespaces needs to be updated with current best practices
Format needs to be updated using SSGT & GJXDM model of subset schema & proxies, constraint/extension schema, and implementation—Can this be done with no impact?

10. Technical Challenges
Class generation: used tools such as Microsoft’s xsd.exe to generate classes from schemas
GJXDM elements contain far more properties than were needed in the system: Constraint schema
GJXDM elements by default create 0-to-many instances: Constraint schema
Extension moves GJXDM element into local namespace!

11. Translation NVPS format must be translatable to and from NLETS format
NLETS format must be translatable to and from NDPIX format
XSLT: too slow for production use
Solution: convert XML formats to and from base classes

12. “Clearinghouse-to-Clearinghouse” Methodology
NVPS may reach a very broad audience of users of NLETS’ format
More moving pieces = More things that can go wrong!
NLETS use of GJXDM
Only header information and wrappers need to be translated
Greatest benefit of GJXDM usage: clearinghouse specifications may be easily mapped to each other with common elements!

13. Lessons Learned Define data model as early as possible
Use SSGT after data modeling is complete elements are identified: it’s hard to go back after changing constraints and minOccurs/maxOccurs
Provide regular communication between participants
Identify networks, vendors, formats, personnel, tools, and commercial products used
Network issues are showstoppers until resolved: identify early!