Personal knowledge base

From Wikipedia, the free encyclopedia

A personal knowledge base (PKB) is an electronic tool used by an individual to express, capture, and later retrieve personal knowledge. It differs from a traditional database in that it contains subjective material particular to the owner, that others may not agree with nor care about. Importantly, a PKB consists primarily of knowledge, rather than information; in other words, it is not a collection of documents or other sources an individual has encountered, but rather an expression of the distilled knowledge the owner has extracted from those sources or from elsewhere.[1][2][3]

The term personal knowledge base was mentioned as early as the 1980s,[4][5][6][7] but the term came to prominence in the 2000s when it was described at length in publications by computer scientist Stephen Davies and colleagues,[1][2] who compared PKBs on a number of different dimensions, the most important of which is the data model that each PKB uses to organize knowledge.[1]: 18 [3]

Data models[edit]

Davies and colleagues examined three aspects of the data models of PKBs:[1]: 19–36 

  • their structural framework, which prescribes rules about how knowledge elements can be structured and interrelated (as a tree, graph, tree plus graph, spatially, categorically, as n-ary links, chronologically, or ZigZag);
  • their knowledge elements, or basic building blocks of information that a user creates and works with, and the level of granularity of those knowledge elements (such as word/concept, phrase/proposition, free text notes, links to information sources, or composite); and
  • their schema, which involves the level of formal semantics introduced into the data model (such as a type system and related schemas, keywords, attribute–value pairs, etc.).

Davies and colleagues also emphasized the principle of transclusion, "the ability to view the same knowledge element (not a copy) in multiple contexts", which they considered to be "pivotal" to an ideal PKB.[1][2] They concluded, after reviewing many design goals, that the ideal PKB was still to come in the future.[1][2]

Personal knowledge graph[edit]

In their publications on PKBs, Davies and colleagues discussed knowledge graphs as they were implemented in some software of the time.[1][2] Later, other writers used the term personal knowledge graph (PKG) to refer to a PKB featuring a graph structure and graph visualization.[8] However, the term personal knowledge graph is also used by software engineers to refer to the different subject of a knowledge graph about a person,[9] in contrast to a knowledge graph created by a person in a PKB.[10]

Software architecture[edit]

Davies and colleagues also differentiated PKBs according to their software architecture: file-based, database-based, or client–server systems (including Internet-based systems accessed through desktop computers and/or handheld mobile devices).[1]: 37–41 


Non-electronic personal knowledge bases have probably existed in some form for centuries: Leonardo da Vinci's journals and notes are a famous example of the use of notebooks. Commonplace books, florilegia, annotated private libraries, and card files (in German, Zettelkästen) of index cards and edge-notched cards are examples of formats that have served this function in the pre-electronic age.[11]

Undoubtedly the most famous early formulation of an electronic PKB was Vannevar Bush's description of the "memex" in 1945.[1][2][12] In a 1962 technical report, human–computer interaction pioneer Douglas Engelbart (who would later become famous for his 1968 "Mother of All Demos" that demonstrated almost all the fundamental elements of modern personal computing) described his use of edge-notched cards to partially model Bush's memex.[13]


In their 2005 paper, Davies and colleagues mentioned the following, among others, as examples of software applications that had been used to build PKBs using various data models and architectures:[1]

Open source
Closed source

See also[edit]


  1. ^ a b c d e f g h i j Davies, Stephen; Velez-Morales, Javier; King, Roger (August 2005). Building the memex sixty years later: trends and directions in personal knowledge bases (Technical report). Boulder, Colo.: Department of Computer Science, University of Colorado at Boulder. CU-CS-997-05.
  2. ^ a b c d e f Davies, Stephen (February 2011). "Still building the memex". Communications of the ACM. 54 (2): 80–88. doi:10.1145/1897816.1897840. S2CID 9551946. Archived from the original on 2021-06-24.
  3. ^ a b See also the dissertation of Max Völkel, which examined personal knowledge data models, and proposed a meta-model called "Conceptual Data Structures": Völkel, Max (January 2010). Personal knowledge models with semantic technologies (Ph.D. thesis). Karlsruhe: Faculty of Economics, Karlsruhe Institute of Technology, University of the State of Baden-Württemberg, and National Laboratory of the Helmholtz Association. doi:10.5445/IR/1000019641. OCLC 837821583.
  4. ^ Brooks, Tom (April 1985). "New technologies and their implications for local area networks". Computer Communications. 8 (2): 82–87. doi:10.1016/0140-3664(85)90218-X.
  5. ^ Krüger, Gerhard (1986). "Future information technology—motor of the 'information society'". In Henn, Rudolf (ed.). Employment and the transfer of technology. Berlin; New York: Springer-Verlag. pp. 39–52. doi:10.1007/978-3-642-71292-0_4. ISBN 3540166394. OCLC 14108228.
  6. ^ Forman, George E. (1988). "Making intuitive knowledge explicit through future technology". In Forman, George E.; Pufall, Peter B. (eds.). Constructivism in the computer age. The Jean Piaget Symposium series. Hillsdale, NJ: Lawrence Erlbaum Associates. pp. 83–101. ISBN 0805801014. OCLC 16922453.
  7. ^ Smith, Catherine F. (1991). "Reconceiving hypertext". In Hawisher, Gail E.; Selfe, Cynthia L. (eds.). Evolving perspectives on computers and composition studies: questions for the 1990s. Urbana, IL: National Council of Teachers of English. pp. 224–252. ISBN 0814111661. OCLC 23462809.
  8. ^ Pyne, Yvette; Stewart, Stuart (March 2022). "Meta-work: how we research is as important as what we research". British Journal of General Practice. 72 (716): 130–131. doi:10.3399/bjgp22X718757. PMC 8884432. PMID 35210247.
  9. ^ For example: Li, Xiang; Tur, Gokhan; Hakkani-Tür, Dilek; Li, Qi (December 2014). "Personal knowledge graph population from user utterances in conversational understanding". SLT 2014: 2014 IEEE Workshop on Spoken Language Technology: proceedings: December 7–10, 2014, South Lake Tahoe, Nevada, U.S.A. Piscataway, NJ: IEEE. pp. 224–229. doi:10.1109/SLT.2014.7078578. ISBN 9781479971305. OCLC 945951970. S2CID 6428777. And: Cao, Lei; Zhang, Huijun; Feng, Ling (January 2022). "Building and using personal knowledge graph to improve suicidal ideation detection on social media". IEEE Transactions on Multimedia. 24: 87–102. arXiv:2012.09123. doi:10.1109/TMM.2020.3046867. S2CID 229210559.
  10. ^ Balog, Krisztian; Mirza, Paramita; Skjæveland, Martin G.; Wang, Zhilin (June 2022). "Report on the Workshop on Personal Knowledge Graphs (PKG 2021) at AKBC 2021" (PDF). ACM SIGIR Forum. 56 (1): 1–11 (8). Archived (PDF) from the original on 2022-07-11. What does 'personal' in PKG mean? It could be taken to mean (objective) facts about the user (I ate lunch at restaurant X on date Y. I like fish.), subjective beliefs of the user ([I believe that] Pineapple pizza is just wrong. The Earth is flat.), or objective facts that are of particular interest to the user (Pineapple pizza is also often called Hawaiian Pizza).
  11. ^ For example, two articles that describe the use of edge-notched cards as a personal knowledge base in health and medicine are: Hoff, Wilbur (May 1967). "A health information retrieval system for personal use". Journal of School Health. 37 (5): 251–254. doi:10.1111/j.1746-1561.1967.tb00505.x. PMID 5182183. And: Manning, Phil R.; DeBakey, Lois (1987). "The personal information center". Medicine, preserving the passion (1st ed.). New York: Springer-Verlag. pp. 57–71 (59). doi:10.1007/978-1-4757-1954-3_3. ISBN 0387963618. OCLC 13580831. Another mention of its use by a writer is: Piercy, Marge (1982). Parti-colored blocks for a quilt. Ann Arbor: University of Michigan Press. pp. 27. doi:10.3998/mpub.7442. ISBN 0472063383. OCLC 8476006. I have a memory annex which serves my purposes. It uses edge-notched cards.
  12. ^ Bush, Vannevar (July 1945). "As we may think". Atlantic Monthly. 176 (1): 101–108.
  13. ^ Engelbart, Douglas C. (1962). "Some possibilities with cards and relatively simple equipment". Augmenting human intellect: a conceptual framework. Menlo Park, CA: Stanford Research Institute. OCLC 8671016. Archived from the original on 2011-05-04. Retrieved 2018-08-12.