The Tree of Knowledge

The best known method for sharing knowledge is a library system, which is a system that categorizes all knowledge components within a defined topology. In the OTTER Project, there is a topology with four layers: innovation, business, academia, and federation.

Innovation components are uniquely created to represent a digital twin of an entity such as an organization, a person, a project, etc. They are a combination of selected knowledge components from the other layers within the knowledge library.  They are considered private and users of the reusable components of the knowledge library.

For business, the NAICS codes (North American Industry Classification System) are applied. These codes are well defined and can be found at: http://www.census.gov/eos/www/naics/.

Academia applies the codes of the CIP (Classification of Instructional Programs). These codes and their full descriptions can be found at: http://nces.ed.gov/ipeds/cipcode.

The OtterServer provides the infrastructure for the Federation layer that supports the  sharing of knowledge components consisting of:

  • Persistent data and its metadata,
  • Services and metadata, and
  • Applications for implementing services.

Using this topology, the Tree of Knowledge is formed for finding and cataloging knowledge. The tree has leaves, as defined by the NAICS standard for categorizing business types. The limbs are combined academic disciples, as defined in the CIP 2010. The federation roots provide consistency for a firm foundation.

The crosswalk that links NAICS codes to CIP 2010 requires the combination of multiple published crosswalks. This is a process that needs refinement relative to knowledge sharing, and will be a subject of a later post.

Tree of Knowledge

If your browser allows, you can click the image above to show a larger view so the text is more readable. Also, if you’re using a mouse, hovering over a leaf or a node where two limbs come together will show the list of contributing CIP 2010 codes.

The tree is dynamically created. This process begins with the business nodes. Nodes are combined two at a time and replaced by a single node. This continues until there is only one node remaining. This node is the trunk of the tree. The combination process first finds a node with the least number of assigned academic disciplines and combines it with a node with the most similar CIP assignments.

A knowledge component would be classified with a single code from business, academic discipline, or OTTER federation. For business, the knowledge component would be found in a leaf. For an academic discipline, a knowledge component could be found in multiple limbs of the tree as well as in the trunk of the tree.

The Tree of Knowledge only references the highest group of NAICS and CIP codes. The highest level of NAICS has the following codes:


11 Agriculture, Forestry, Fishing and Hunting
21 Mining, Quarrying, and Oil and Gas Extraction
22 Utilities
23 Construction
31-33 Manufacturing
42 Wholesale Trade
44-45 Retail Trade
48-49 Transportation and Warehousing
51 Information
52 Finance and Insurance
53 Real Estate and Rental and Leasing
54 Professional, Scientific, and Technical Services
55 Management of Companies and Enterprises
56 Administrative and Support and Waste Management and Remediation Services
61 Educational Services
62 Health Care and Social Assistance
71 Arts, Entertainment, and Recreation
72 Accommodation and Food Services
81 Other Services (except Public Administration)
92 Public Administration


Each of these codes is subdivided into more detail. For example: “22 Utilities” is sub-divided into the following categories:

    • 2211 Electric Power Generation, Transmission and Distribution
      • 22111 Electric Power Generation
        • 221111 Hydroelectric Power Generation
        • 221112 Fossil Fuel Electric Power Generation
        • 221113 Nuclear Electric Power Generation
        • 221114 Solar Electric Power Generation
        • 221115 Wind Electric Power Generation
        • 221116 Geothermal Electric Power Generation
        • 221117 Biomass Electric Power Generation
        • 221118 Other Electric Power Generation
      • 22112 Electric Power Transmission, Control, and Distribution
        • 221121 Electric Bulk Power Transmission and Control
        • 221122 Electric Power Distribution
    • 2212 Natural Gas Distribution
      • 22121 Natural Gas Distribution
      • 221210 Natural Gas Distribution
    • 2213 Water, Sewage and Other Systems
      • 22131 Water Supply and Irrigation Systems
      • 22132 Sewage Treatment Facilities
      • 22133 Steam and Air-Conditioning Supply

Business knowledge components classified at higher levels in a category should apply to multiple of its sub-categories. For instance, the standard  IEC 61850 is used by devices for electrical substation automation systems. This knowledge component should be catalogued within 22 utilities. It might be proper to assign it the code 2211 for electric power, or if it only pertains to distribution, the code 22112 may be a more accurate assignment.

The CIP also has a topology for classifications that are subdivided. Using this topology, knowledge components should be classified at the appropriate level in the same manner as the NAIC codes. Higher level codes are for knowledge components that apply to multiple sub-categories.

The OtterServer enforces the tree structure by requiring that documents within a knowledge component can only have a single classification code, and can only import documents from the same layer or from a lower level layer. In other words, a business document can import another business document, an academia document, or an infrastructure document. An academia document can only import another academia document or an infrastructure document.

The academia documents provide the principles of knowledge. Most of these will not change significantly over time, although there may be new or extended versions. Businesses will change and should be dependent on the proven principles of knowledge found in academia. Any business document not dependent upon academic disciplines can be viewed as having no principles.

The Tree of Knowledge, like a library, provides the means for locating shared knowledge, and the OtterServer provides the means to utilize that knowledge. Due to the consistency of descriptive logic languages and the OtterServer framework, all knowledge components are homogeneous and inter-operable.

Leave a Reply

Your email address will not be published. Required fields are marked *