# Presentation: 198566

## Real-Time Data Accessibility via RMI Client/ServerTechnology

- FY 2004 NOAA HPCC Funded Project
- Janet S. Gibson
- 6/1/05

**Notes:**
Create a real-time data hub via Java Remote Method Invocation.

## Accomplishments

- Verified that the original concept of collecting and archiving data over the internet at a single machine and then serving the data to client programs for viewing, is a solid concept that works well
- Determined that because of security issues, RMI is not the best choice for this system
- Demonstrated that HTTP is a much better choice

**Notes:**
RMI required extra administration.  Tunneling was more overhead and administration.  RMI works better in small network and where applications and clients are strongly coupled or application is distributed across machines.   Within the radar RMI worked well. Extending it across the network showed that it is not appropriate over network. 

## Deliverables

- Development and demonstration of a client/server distributed object system
- Multiple simultaneous real-time data streams
- Multiple display clients
- Web-based applets and Java applications to display remote sensing products
- Project Final Report

**Notes:**
Create the java client and server to receive remote data, archive data and redistribute for display to java clients.

## System Overview

**Notes:**
Data sources scanning radar, radiometer, surf met, ruc –model, icing (derrived product).  Any data source can be adding by writting new data formatter. Data formatter takes raw data and packages it in it’s archive format. Data relay posts through http to server.  Server archives and receives get requests from clients.  Client are java applications for display and archive.  Surface met, radiometer, icing , scanning radar displays exist.  PDA is network and programming capable, but user interface needs to be customized.  

## System Strengths

- The system is built upon one centralized server
- It supports multiple remote clients
- Typically you have a reformatter and relay for each data source
- Can be one or more processes
-  Functions over any network which supports http

## System Components

- Data Source
- Data Formatter
- Relay
- DataRexx Server
- Display software
- Additional archival software

## Introduction to DataRexx

- General purpose data collection, archiving & distribution server
- Works across the internet and through firewalls
- Supports multiple, simultaneous input & output data streams in near real-time
- Platform independent
- Supports arbitrary binary formats
- Provides a standard API for data producer & data consumer client programs
- Licensed without fee (free)

## Example Multiple Real-Time Data Views

- Radiometer & surface met. products

- Radar polarization product

## Technology Employed

- Java Language
- Robust, object-oriented
- J2EE Components (JSPs and servlets)
- High quality, robust web programming capability
- Apache Tomcat
- High quality J2EE engine and web server
- HTTP
- Standard web protocol requires no extra configuration or private ports
- Motivation for all of the above
- OS independent (Windows, Linux, Solaris, Mac)
- Well supported, widely used, vendor independent, free

## Lessons Learned

- RMI worked well for closely coupled components but was not suitable for wide-area network solutions
- Security issues
- Bandwidth overhead
- Administration overhead
- HTTP works well and does not have the firewall or security issues

## Users of the System as it Exists

- GRIDS team
- Gap-filling radar team
- GRIDS web-site users
- Private pilots
- Students
- Teachers
- Researchers
- Modelers
- Project Managers
- Any group looking for real-time remote sensing data distribution web solutions

##  Recommendations

- Develop this solution to full production quality product
- Extend display of near real-time data to wireless devices
- Data presentation becomes accessible beyond desktop
- PDAs
- Cellular Phones
- Laptops
- Make server package available to community

**Notes:**
Finishing web applets.  Remote administration. Live, real-world testing.

## Wireless Applications

- Weather forecasts and information
- Water information
- Emergency response
- Protect lives and resources
- Improve field research connectivity
- Increase user access to NOAA data

## Conclusion

- Have demonstrated a technology for serving and displaying remote sensing data in near real-time
- The system improves “Timely Access to Weather and Water Information”
- Employs advanced technology and internet technology
- Solution is widely applicable to NOAA data distribution
- Offers the foundation for enormous public outreach