# ConcurTaskTrees

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'''ConcurTaskTrees (CTT)'''<ref name=ctt>{{cite journal|last=Paternò|first=Fabio|title=ConcurTaskTrees: An Engineered Notation for Task Models|journal=The Handbook of Task Analysis for Human-Computer Interaction|year=2003|pages=483–503|url=http://giove.isti.cnr.it/attachments/publications/2003-A1-07.pdf}}</ref> is a notation for task model specifications used in the design of interactive applications, particularly within model-based [user interface](/source/user_interface) design.

The main features of CTT are:
* Hierarchical structure, which provides a large range of granularity in describing large and small task structures; 
* Graphical syntax, which reflects the logical structure in a tree-like form;
* Concurrent notation, enabling flexible task ordering.
In the field of [human–computer interaction](/source/human%E2%80%93computer_interaction), task models describe the logical activities an application should support to help users achieve their goals. Methods have been developed to derive user interfaces for different platforms from CTT specifications.<ref name=cttUI>{{cite journal|last=Paternò|first=Fabio|author2=Santoro Carmen|author3=Spano Lucio Davide|title= Engineering the authoring of usable service front ends.|journal=Journal of Systems and Software|volume=84|issue=10|pages=1806–1822|date=October 2011|url=http://giove.cnuce.cnr.it/attachments/publications/engineering_the_authoring.pdf|doi=10.1016/j.jss.2011.05.025|citeseerx=10.1.1.304.366}}</ref> The last evolution has been the introduction of preconditions.<ref name=cttpre>{{cite journal|last=Manca|first=Marco|author2=Paternò Fabio|author3=Santoro Carmen|author4=Spano Lucio Davide|title=Considering task pre-conditions in model-based user interface design and generation.|journal=Proceedings of the 2014 ACM SIGCHI Symposium on Engineering Interactive|url=http://giove.isti.cnr.it/attachments/publications/p149-manca.pdf}}</ref>

CTT has been applied in both academia and industry, particularly in domains such as [enterprise resource planning](/source/enterprise_resource_planning) (ERP) and safety-critical systems, including air traffic control.<ref>[https://archive.today/20250612105051/https://web.archive.org/web/20201130041814/https://ext.eurocontrol.int/ehp/?q=node/1617 "Concur Task Trees (CTT) Task Modeller"]. ''[SESAR Joint Undertaking](/source/SESAR_Joint_Undertaking)''. Archived from [https://www.empat.tech/blog/software-development-solutions the original] on 2020-11-30. Retrieved 2025-06-12.</ref> It has also been considered by the [World Wide Web Consortium](/source/World_Wide_Web_Consortium) (W3C) for task model standardization.[http://www.w3.org/TR/task-models/]

Usability studies have been conducted on CTT,<ref name="cttUs">{{cite book |last1=Vigo |first1=Markel |url=https://research.manchester.ac.uk/en/publications/the-usability-of-task-modeling-tools |title=2017 IEEE Symposium on Visual Languages and Human-Centric Computing (VL/HCC) |last2=Santoro |first2=Carmen |last3=Paterno |first3=Fabio |year=2017 |isbn=978-1-5386-0443-4 |pages=95–99 |chapter=The usability of task modeling tools |doi=10.1109/VLHCC.2017.8103455 |chapter-url=https://www.research.manchester.ac.uk/portal/files/58359724/ctte_study.pdf |s2cid=7374320}}</ref> and it has been mapped into the [Unified Modeling Language](/source/Unified_Modeling_Language) (UML).<ref name="cttUML">{{cite book |last1=Nbrega |first1=Leonel |first2=Nuno |last2=Nunes |first3=Helder |last3=Coelho |title=Interactive Systems. Design, Specification, and Verification. DSV-IS 2005 |chapter=Mapping ConcurTaskTrees into UML 2.0 |volume=3941 |year=2006 |pages=237–248 |chapter-url=https://www.researchgate.net/publication/221620818_Mapping_ConcurTaskTrees_into_UML_20 |doi=10.1007/11752707_20 |series=Lecture Notes in Computer Science |isbn=978-3-540-34145-1}}</ref>

== Tool support ==
The editing and analysis of task models is supported by the [http://giove.isti.cnr.it/tools/CTTE/home '''ConcurTaskTrees Environment'''] ('''CTTE''').<ref name=ctte>{{cite journal|last=Mori|first=Giulio|author2=Paternò Fabio|author3=Santoro Carmen|title=CTTE: Support for Developing and Analysing Task Models for Interactive System Design|journal=IEEE Transactions on Software Engineering|volume=28|issue=8|year=2002|pages=797–813|url=http://giove.isti.cnr.it/attachments/publications/2002-A0-45_0.pdf|doi=10.1109/tse.2002.1027801|citeseerx=10.1.1.359.5986}}</ref>
The executable code is publicly available and free to download. 

== References ==
{{Reflist}}

== External links ==
* Leonel Nobrega, Jardim Nunes Nunes, Helder Coelho: "[http://pdf.aminer.org/000/162/822/mapping_concurtasktrees_into_uml.pdf Mapping ConcurTaskTrees into UML 2.0]", ''Interactive Systems Design Specification and Verification'' (2006), Volume 33, Issue 228. Springer. Pages: 237–248.
* Model-based User Interfaces Incubator Group: [http://www.w3.org/2005/Incubator/model-based-ui/wiki/ConcurTaskTrees ConcurTaskTrees].
*Fabio Paternò: "[http://www.ercim.eu/publication/Ercim_News/enw31/paterno.html Using ConcurTaskTrees for Designing New Interactive Applications in an Industrial Context]", ERCIM News No.31 - October 1997.
* {{cite CiteSeerX|first1=F.|last1=Paterno|first2= C.|last2=Mancini|first3=S.|last3=Meniconi|citeseerx=10.1.1.86.585|title=ConcurTaskTrees: A Diagrammatic Notation for Specifying Task Models|pages=362–369|date=1997}}
* Fabio Paternò: [http://giove.isti.cnr.it/tools/CTTE/CTT_publications/publications.html Publications Reporting Work in which ConcurTaskTrees (CTT) has been used].
* Ana Barbosa, Ana C.R. Paiva, José Creissac Campos: "[http://portal.acm.org/citation.cfm?id=1996516&CFID=34406612 Test case generation from mutated task models]", ''EICS '11 Proceedings of the 3rd ACM SIGCHI symposium on Engineering interactive computing systems'', pages 175–184.
*http://www.cubeos.org/lectures/W/ln_9.pdf
* D. Reichart, A. Dittmar, P. Forbrig, M. Wurdel: [https://archive.today/20130202210705/http://www.springerlink.com/content/a7xr3218t75mn237/?p=efc0e4a57a5f4f9d8dc01140f2767640&pi=7 Tool Support for Representing Task Models, Dialog Models and User-Interface Specifications]", ''Interactive Systems. Design, Specification, and Verification''. [Lecture Notes in Computer Science](/source/Lecture_Notes_in_Computer_Science) Volume 5136, 2008, pp 92-95.
* Josefina Guerrero García, Jean Vanderdonckt, Juan Manuel González Calleros, Marco Winckler : "[https://archive.today/20130203183649/http://www.springerlink.com/content/j412467087813552/?p=efc0e4a57a5f4f9d8dc01140f2767640&pi=8 Towards a Library of Workflow User Interface Patterns]". ''Interactive Systems. Design, Specification, and Verification''. Lecture Notes in Computer Science Volume 5136, 2008, pp 96-101.
* Marco Blumendorf, Grzegorz Lehmann, Sebastian Feuerstack, Sahin Albayrak: "[https://archive.today/20130203020758/http://www.springerlink.com/content/p3842241wu563674/?p=3574567edf4f4e99bc430a8e49a80eed&pi=21 Executable Models for Human-Computer Interaction]", ''Executable Models for Human-Computer Interaction''. Lecture Notes in Computer Science Volume 5136, 2008, pp 238–251.
* Dan Diaper, Neville E. Stanton, eds.: ''[https://books.google.com/books?id=LG3k9F68J8EC&dq=ctte+autore:f-paterno&pg=RA1-PA483 The Handbook of Task Analysis for Human-computer Interaction]'', 2004.

Category:Software design

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Adapted from the Wikipedia article [ConcurTaskTrees](https://en.wikipedia.org/wiki/ConcurTaskTrees) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/ConcurTaskTrees?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.