{{short description|Knowledge management software}} {{about|knowledge management software|the general concept|Personal knowledge management}} {{InfoMaps}} 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.<ref name="Davies 2005">{{Cite tech report |last1=Davies |first1=Stephen |last2=Velez-Morales |first2=Javier |last3=King |first3=Roger |date=August 2005 |title=Building the memex sixty years later: trends and directions in personal knowledge bases |number=CU-CS-997-05 |location=Boulder, Colo. |institution=Department of Computer Science, University of Colorado at Boulder |url=https://scholar.colorado.edu/concern/reports/t722h9830}}</ref><ref name="Davies 2011">{{Cite journal |last=Davies |first=Stephen |date=February 2011 |title=Still building the memex |journal=Communications of the ACM |volume=54 |issue=2 |pages=80–88 |doi=10.1145/1897816.1897840 |s2cid=9551946 |url=https://cacm.acm.org/magazines/2011/2/104378-still-building-the-memex/fulltext |archive-url=https://web.archive.org/web/20210624161048/https://cacm.acm.org/magazines/2011/2/104378-still-building-the-memex/fulltext |archive-date=2021-06-24 |url-status=live}}</ref><ref name="Völkel 2010">See also the dissertation of Max Völkel, which examined personal knowledge data models, and proposed a meta-model called "Conceptual Data Structures": {{Cite thesis |last=Völkel |first=Max |title=Personal knowledge models with semantic technologies |date=January 2010 |publisher=Faculty of Economics, Karlsruhe Institute of Technology, University of the State of Baden-Württemberg, and National Laboratory of the Helmholtz Association |url=https://publikationen.bibliothek.kit.edu/1000019641 |doi=10.5445/IR/1000019641 |oclc=837821583 |type=Ph.D. thesis |location=Karlsruhe}}</ref>
The term {{em|personal knowledge base}} was mentioned as early as the 1980s,<ref name="Brooks 1985">{{Cite journal |last=Brooks |first=Tom |date=April 1985 |title=New technologies and their implications for local area networks |journal=Computer Communications |volume=8 |issue=2 |pages=82–87 |doi=10.1016/0140-3664(85)90218-X }}</ref><ref name="Kruger 1986">{{Cite book |last=Krüger |first=Gerhard |title=Employment and the transfer of technology |date=1986 |publisher=Springer-Verlag |isbn=3540166394 |editor-last=Henn |editor-first=Rudolf |location=Berlin; New York |pages=39–52 |chapter=Future information technology—motor of the 'information society' |doi=10.1007/978-3-642-71292-0_4 |oclc=14108228 }}</ref><ref name="Forman 1988">{{Cite book |last=Forman |first=George E. |title=Constructivism in the computer age |date=1988 |publisher=Lawrence Erlbaum Associates |isbn=0805801014 |editor-last=Forman |editor-first=George E. |series=The Jean Piaget Symposium series |location=Hillsdale, NJ |pages=[https://archive.org/details/constructivismin0000unse/page/83 83–101] |chapter=Making intuitive knowledge explicit through future technology |oclc=16922453 |editor-last2=Pufall |editor-first2=Peter B. |chapter-url=https://archive.org/details/constructivismin0000unse/page/83 |chapter-url-access=registration}}</ref><ref name="Smith 1991">{{Cite book |last=Smith |first=Catherine F. |title=Evolving perspectives on computers and composition studies: questions for the 1990s |date=1991 |publisher=National Council of Teachers of English |isbn=0814111661 |editor-last=Hawisher |editor-first=Gail E. |location=Urbana, IL |pages=[https://archive.org/details/evolvingperspect00gail/page/224 224–252] |chapter=Reconceiving hypertext |oclc=23462809 |editor-last2=Selfe |editor-first2=Cynthia L. |chapter-url=https://archive.org/details/evolvingperspect00gail/page/224 |chapter-url-access=registration}}</ref> but the term came to prominence in the 2000s when it was described at length in publications by computer scientist Stephen Davies and colleagues,<ref name="Davies 2005" /><ref name="Davies 2011" /> 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.<ref name="Davies 2005" />{{rp|18}}<ref name="Völkel 2010" />
==Data models== Davies and colleagues examined three aspects of the data models of PKBs:<ref name="Davies 2005" />{{rp|19–36}}
* their {{em|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 {{em|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 {{em|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.<ref name="Davies 2005" /><ref name="Davies 2011" /> They concluded, after reviewing many design goals, that the ideal PKB was still to come in the future.<ref name="Davies 2005" /><ref name="Davies 2011" />
===Personal knowledge graph=== In their publications on PKBs, Davies and colleagues discussed knowledge graphs as they were implemented in some software of the time.<ref name="Davies 2005" /><ref name="Davies 2011" /> Later, other writers used the term '''personal knowledge graph''' (PKG) to refer to a PKB featuring a graph structure and graph visualization.<ref name="Pyne & Stewart 2022">{{cite journal |last1=Pyne |first1=Yvette |last2=Stewart |first2=Stuart |date=March 2022 |title=Meta-work: how we research is as important as what we research |journal=British Journal of General Practice |volume=72 |issue=716 |pages=130–131 |pmid=35210247 |pmc=8884432 |doi=10.3399/bjgp22X718757}}</ref> However, the term {{em|personal knowledge graph}} is also used by software engineers to refer to the different subject of a knowledge graph {{em|about}} a person,<ref>For example: {{cite book |last1=Li |first1=Xiang |last2=Tur |first2=Gokhan |last3=Hakkani-Tür|author3-link=Dilek Hakkani-Tür |first3=Dilek |last4=Li |first4=Qi |date=December 2014 |chapter=Personal knowledge graph population from user utterances in conversational understanding |title=SLT 2014: 2014 IEEE Workshop on Spoken Language Technology: proceedings: December 7–10, 2014, South Lake Tahoe, Nevada, U.S.A. |publisher=IEEE |location=Piscataway, NJ |pages=224–229 |isbn=9781479971305 |oclc=945951970 |doi=10.1109/SLT.2014.7078578 |s2cid=6428777 |chapter-url=https://www.researchgate.net/publication/282177475}} And: {{cite journal |last1=Cao |first1=Lei |last2=Zhang |first2=Huijun |last3=Feng |first3=Ling |date=January 2022 |title=Building and using personal knowledge graph to improve suicidal ideation detection on social media |journal=IEEE Transactions on Multimedia |volume=24 |pages=87–102 |doi=10.1109/TMM.2020.3046867|arxiv=2012.09123 |bibcode=2022ITMm...24...87C |s2cid=229210559 }}</ref> in contrast to a knowledge graph {{em|created by}} a person in a PKB.<ref>{{cite journal |last1=Balog |first1=Krisztian |last2=Mirza |first2=Paramita |last3=Skjæveland |first3=Martin G. |last4=Wang |first4=Zhilin |date=June 2022 |title=Report on the Workshop on Personal Knowledge Graphs (PKG 2021) at AKBC 2021 |journal=ACM SIGIR Forum |volume=56 |issue=1 |pages=1–11 (8) |quote=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''). |url=https://www.sigir.org/wp-content/uploads/2022/07/p04.pdf |archive-url=https://web.archive.org/web/20220711210242/https://www.sigir.org/wp-content/uploads/2022/07/p04.pdf |archive-date=2022-07-11 |url-status=live}}</ref>
== Software architecture == 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).<ref name="Davies 2005" />{{rp|37–41}}
== History == 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, {{em|florilegia}}, annotated private libraries, and card files (in German, {{lang|de|Zettelkästen}}) of index cards and edge-notched cards are examples of formats that have served this function in the pre-electronic age.<ref>For example, two articles that describe the use of edge-notched cards as a personal knowledge base in health and medicine are: {{cite journal |last=Hoff |first=Wilbur |date=May 1967 |title=A health information retrieval system for personal use |journal=Journal of School Health |volume=37 |issue=5 |pages=251–254 |doi=10.1111/j.1746-1561.1967.tb00505.x |pmid=5182183 }} And: {{Cite book |last1=Manning |first1=Phil R. |title=Medicine, preserving the passion |last2=DeBakey |first2=Lois |date=1987 |publisher=Springer-Verlag |isbn=0387963618 |edition=1st |location=New York |pages=[https://archive.org/details/medicinepreservi00mann/page/57 57–71 (59)] |chapter=The personal information center |doi=10.1007/978-1-4757-1954-3_3 |oclc=13580831 |chapter-url=https://archive.org/details/medicinepreservi00mann/page/57 |chapter-url-access=registration}} Another mention of its use by a writer is: {{cite book |last=Piercy |first=Marge |author-link=Marge Piercy |date=1982 |title=Parti-colored blocks for a quilt |location=Ann Arbor |publisher=University of Michigan Press |pages=[https://archive.org/details/particoloredbloc00pier/page/27 27] |isbn=0472063383 |oclc=8476006 |url=https://archive.org/details/particoloredbloc00pier/page/27 |url-access=registration |doi=10.3998/mpub.7442 |quote=I have a memory annex which serves my purposes. It uses edge-notched cards.}}</ref>
Undoubtedly the most famous early formulation of an electronic PKB was Vannevar Bush's description of the "memex" in 1945.<ref name="Davies 2005" /><ref name="Davies 2011" /><ref name="Bush 1945">{{Cite journal |last=Bush |first=Vannevar |date=July 1945 |title=As we may think |url=https://www.theatlantic.com/magazine/archive/1945/07/as-we-may-think/303881/ |journal=Atlantic Monthly |volume=176 |issue=1 |pages=101–108 }}</ref> 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.<ref>{{Cite book |last=Engelbart |first=Douglas C. |url=http://www.dougengelbart.org/pubs/augment-3906.html |title=Augmenting human intellect: a conceptual framework |date=1962 |publisher=Stanford Research Institute |location=Menlo Park, CA |chapter=Some possibilities with cards and relatively simple equipment |oclc=8671016 |access-date=2018-08-12 |archive-url=https://web.archive.org/web/20110504035147/http://www.dougengelbart.org/pubs/augment-3906.html |archive-date=2011-05-04 |url-status=dead}}</ref>
==Examples== The following software applications have been used to build PKBs using various data models and architectures. The list includes software mentioned by Davies and colleagues in their 2005 paper,<ref name="Davies 2005" /> and additional software.
;Open source * Compendium<ref name="Davies 2005" /> * Haystack (MIT project)<ref name="Davies 2005" /> * Joplin<ref name="Das 2024">{{cite web |last=Das |first=Ankush |date=2024-07-03 |title=9 open source second brain knowledge base tools |url=https://itsfoss.com/open-source-second-brain-apps/ |website=ItsFOSS |access-date=2026-02-23}}</ref> * Logseq<ref name="Das 2024" /> * NoteCards<ref name="Davies 2005" /> * Org-mode<ref>{{cite web |last=Chavan |first=Abhijeet |date=2007-12-01 |title=Get organized with Emacs Org-mode |url=https://www.linuxjournal.com/article/9116 |website=Linux Journal |access-date=2026-02-23}}</ref> * QOwnNotes<ref name="Das 2024" /> * TiddlyWiki<ref>{{cite web |last=Kasiya |first=Chifundo |date=2025-12-10 |title=I built a personal knowledge base without using Notion or Obsidian |url=https://www.makeuseof.com/i-built-personal-knowledge-base-without-using-notion-or-obsidian/ |website=MakeUseOf |access-date=2026-02-23}}</ref>
;Closed source * Evernote<ref>{{cite book |last1=Tsui |first1=Eric |last2=Wang |first2=Wai Ming |last3=Sabetzadeh |first3=Farzad |date=November 2014 |chapter=Enacting personal knowledge management & learning with web services interoperability tools |title=2014 IEEE 3rd International Conference on Cloud Computing and Intelligence Systems |location=Piscataway, NJ |publisher=IEEE |pages=491–494 |doi=10.1109/CCIS.2014.7175785}}</ref> * Microsoft OneNote<ref name="Davies 2005" /> * MindManager<ref name="Davies 2005" /> * MyLifeBits<ref name="Davies 2005" /> * Notion<ref name="Pyne & Stewart 2022" /> * Obsidian<ref name="Pyne & Stewart 2022" /> * Personal Knowbase<ref name="Davies 2005" /> * PersonalBrain<ref name="Davies 2005" /> * Roam<ref name="Pyne & Stewart 2022" /> * Tinderbox<ref name="Davies 2005" />
==See also== {{Div col|colwidth=22em}} * {{annotated link|Computer-assisted qualitative data analysis software}} * {{annotated link|Information system}} * {{annotated link|Issue-based information system}} * {{annotated link|Lifelog}} * {{annotated link|Notetaking}} ** Comparison of notetaking software * {{annotated link|Outliner}} * {{annotated link|Personal knowledge management}} * {{annotated link|Personal wiki}} ** {{slink|List of wiki software#Personal wiki software}} * {{slink|Tag (metadata)#Knowledge tags}} {{Div col end}}
==References== {{Reflist}}
Category:Knowledge representation