Generic Services on the NII

We can define a simple layered architecture for Web (NII) applications which are built in terms of multi-use services as shown in Figure 10. ``Multi-use'' extends the well known dual-use civilian-military interplay to a set of capabilities shared by many different applications. Note the Web is an excellent implementation technology for the COTS (customer off the shelf) choice used in many new defense software systems. There is no precise definition of services and their difference from applications, for services are essentially generic applications, and most applications are complex metaproblems [Fox:95c] built recursively from services and ``sub-applications.'' Thus, there is a grey fuzzy line distinguishing services and applications. We now elaborate five possible NII services.

  
Figure 10: A layered view of Web (NII) software building applications on top of generic services that are in turn built on pervasive technologies.

• WebTop Services---Publishing Productivity, Software Engineering

  We have already discussed these ``WebWord''-like products.

• InfoVISiON---Information, Video, Imagery, Simulation, ON demand

  This includes base database storage, management, query, and dissemination of the full range of multimedia archives of the World's distributed digital libraries, described above. Note delivery of results of a simulation---such as access on demand to a weather model---is included in this service.

• Commerce---Digital Cash, Security, Authentication, etc.

  This collection of services enables electronic commerce, including on-line banking and shopping. These services are also essential for the use of the WWW for processing and exchange of proprietary and classified (military) data.

• Collaboration---Real-Time Interactive and ``Batch''

  This includes desktop video conferencing, three-dimensional graphics MOOs, geographically distributed CAVEs leading to full televirtual interactions. The emerging VRML 2.0 standards will be very important in building virtual environments. As discussed earlier, a wide variety of other types of interactive information exchange is necessary. This underlies the concepts of collaboratories (virtual research groups or scientific laboratories), and the virtual company of the next century's agile manufacturing environment. In the more static mode, we see workflow and configuration control, which allows tightly integrated projects, such as those needed to build a complex system including an aircraft or a large software module with a distributed team.

• Metacomputing---A worldwide collection of computers organized together as a single computational engine for simulation or information processing [Fox:95a].

  This service, discussed in Section 4 can be used to control remote medical and scientific instruments; search the world for information; simulate the expected weather, or link computers in different companies for a multi-disciplinary optimization of a new vehicle.

Some services listed above can be already prototyped in terms of today's Web technologies. For example, base WebTop or early Collaboration services are now becoming available. Some other services are still waiting for their pervasive enabling technologies, such as physical infrastructure that will enable InfoVISiON or security that will enable Internet Commerce. Finally, the computationally extensive NII services, characterized above broadly as ``Metacomputing'' require, as reviewed in Section 4, a major extension of the whole Web paradigm, currently still focused on static page services, but already gradually expanding towards computation and interactive simulation via technologies such as Java and VRML.

• Four Typical Web Windows Application Areas