The logical model of web-services in KnitbITs^®

Information Dynamics

KnitbITs helps managing highly-patterned information. The pattern — also read structure, organization etc. —  is designed by applying the metapattern, an approach to conceptual information modeling with pervasive recognition of context and time.

How does KnitbITs help? A physical person cannot access, add, etc. information directly. In general terms, separately there exists an patterned information set or information resources domain. Then, a particular physical person interfaces with the domain through a personal connection medium. For example, a properly outfitted personal computer is such a medium, but so are other 'personal' devices. Figure 1 sketches at its most abstract how physical person, personal connection medium (PCM) and information resources domain (IRD) are related.

Figure 1.

 

Like the world wide web (www), KnitbITs holds that management over time of an information presentation state doesn't encompass both a personal connection medium and the information resources domain. In other words, their connection is asynchronous.

The asynchronicity of the traditional web is achieved in a straightforward fashion through uniform resource locators (url's). As KnitbITs implements the metapattern, asynchronicity doesn't stop at single, 'flat' references such as url's.

Here is where web services come in. Explained in terms of directed graph theory, a physical person initiates a cycle when (s)he activates either a particular node or a particular kind of relationship. A message is then compiled and sent from the PCM to the IRD. It calls a web service for a response: the IRD answers the call from the PCM.

In case of activation of a kind of relationship, the IRD 'answers' with the corresponding relationship instances and the individual nodes they lead to. See figure 2.

Figure 2.

 

When a node is activated by the physical person, the interaction cycle finds closure by presenting the kinds of relationships extending to lower-level nodes. See figure 3.

Figure 3.

 

The interaction cycles sketched in figures 2 and 3 alternate.1 In fact, a relationship has many characteristics of a traditional node. See also The twofold variety of nodes in KnitbITs.

The messages KnitbITs exchanges for calling web services go beyond url's because a more powerfully patterned information resources domain, say, metapatterned information, requires coordination along two dimensions.

Along one dimension the information pattern, or structure, is controlled; structural information is usually called metainformation. Of course, the metainformation is itself also structured; all this gives the KnitbITs technology its distinctively recursive flavor.

The second dimension shows the actual information, following rules laid down along the first dimension.

Now, a particular node is a property of a higher-level node (with the upper-most node annex relationship set by definition, i.e., as a boundary condition). What kind of property one node 'fullfils' for another node, i.e., how the two nodes are structurally related, is governed by the higher-level node's metainformation.

The particular node's 'own' metainformation indicates its kinds of properties, fullfilled with other 'pieces' of — actual — information as nodes.

So, from the IRD, a web service always delivers — actual — information according to what kind of property the physical person activates at the PCM. In addition, for every 'piece' of — actual — information its metainformation with regard to kinds of properties is delivered. This allows the physical person, using her/his PCM, to continue browsing the metapattern-structured IRD.

Arriving at the 'final' delivery during a particular cycle, inside  the IRD a host of web services may be involved to gather the relevant information and metainformation. By viewing every exchange essentially as occurring between a — virtual or not — PCM and the IRD, the same basic model applies throughout.

 

 

1. The different calls whose service mechanisms are sketched in figures 2 and 3 are actually bundled by KnitbITs for the PCM. On average, improved user performance results as the most probable next steps in activation are anticipated. However, what counts for this paper is the logical design of web services.

 

 

© web edition 2002.