Podemos listar alguns trabalhos futuros que identificamos ao longo da pesquisa: 1. S´ıntese de modelos KMTS a partir de artefatos de software:
Evoluir o algoritmo de modelos KMTS a partir de diagramas de sequˆencia para considerar estruturas dos diagramas, como a nega¸c˜ao e a estrutura condicional; Propor algoritmos para s´ıntese de KMTS a partir do c´odigo-fonte.
128 CONCLUS ˜OES
Definir outras rela¸c˜oes de refinamento como refinamento modal fraco e o de alfabeto ramificado para modelos KMTS;
Definir outras opera¸c˜oes sobre modelos KMTS, como a opera¸c˜ao quociente (uma opera¸c˜ao dual a opera¸c˜ao de conjun¸c˜ao, que pode ser utilizada para extrair uma vis˜ao em n´ıvel de componente a partir do modelo do sistema); Definir um modo de representar as altera¸c˜oes na composi¸c˜ao paralela nos mo-
delos que a comp˜oem, de forma a refletir modifica¸c˜oes da composi¸c˜ao nos seus modelos;
Implementar algoritmos para calcular conjun¸c˜ao e quociente entre dois modelos KMTS.
3. Reparo de refinamento
´E poss´ıvel usar t´ecnicas de programa¸c˜ao dinˆamica para reusar as solu¸c˜oes j´a produzidas para as causas de falhas j´a analisadas;
Acreditamos ser poss´ıvel trabalhar diretamente sobre um jogo de refinamento, refletindo diretamente as altera¸c˜oes no jogo e analisando seu impacto sem ter que refazer o jogo a cada reparo realizado;
´E poss´ıvel definir algumas heur´ısticas para evitar analisar todos os casos das poss´ıveis mudan¸cas. Estas heur´ısticas podem utilizar informa¸c˜oes do jogo de refinamento para fazer modifica¸c˜oes sem gerar (ou gerando o m´ınimo poss´ıvel) novas causas de falhas;
REFERˆENCIAS BIBLIOGR ´AFICAS
ALFARO, L. D.; HENZINGER, T. A. Interface-based design. In: Engineering theories of software intensive systems. [S.l.]: Springer, 2005. p. 83–104.
ANTONIK, A. et al. 20 years of modal and mixed specifications. Bulletin of the European Association for Theoretical Computer Science, n. 95, 2008.
BAIER, C.; KATOEN, J.-P.; LARSEN, K. G. Principles of model checking. [S.l.]: MIT press, 2008.
BAUER, S. Modal specification theories for component-based design. Tese (Doutorado) — lmu, 2012.
BAUER, S. S. et al. Moving from specifications to contracts in component-based design. In: . Fundamental Approaches to Software Engineering: 15th International Confe- rence, FASE 2012, Held as Part of the European Joint Conferences on Theory and Prac- tice of Software, ETAPS 2012, Tallinn, Estonia, March 24 - April 1, 2012. Proceedings. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. p. 43–58. ISBN 978-3-642-28872-2. Dispon´ıvel em: xhttp://dx.doi.org/10.1007/978-3-642-28872-2z 3y.
BAUER, S. S. et al. A modal specification theory for components with data. In: . Formal Aspects of Component Software: 8th International Symposium, FACS 2011, Oslo, Norway, September 14-16, 2011, Revised Selected Papers. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. p. 61–78. ISBN 978-3-642-35743-5. Dispon´ıvel em: xhttp://dx. doi.org/10.1007/978-3-642-35743-5z 5y.
BECK, K. Embracing change with extreme programming. Computer, IEEE Computer Society Press, Los Alamitos, CA, USA, v. 32, n. 10, p. 70–77, out. 1999. ISSN 0018-9162. Dispon´ıvel em: xhttp://dx.doi.org/10.1109/2.796139y.
BENEˇs, N.; ˇCERN´a, I.; KˇrET´ıNSK´y, J. Modal transition systems: Composition and ltl model checking. In: BULTAN, T.; HSIUNG, P.-A. (Ed.). Automated Technology for Verification and Analysis. Springer Berlin Heidelberg, 2011, (Lecture Notes in Computer Science, v. 6996). p. 228–242. ISBN 978-3-642-24371-4. Dispon´ıvel em: xhttp://dx.doi. org/10.1007/978-3-642-24372-1z 17y.
BENEˇs, N. et al. On determinism in modal transition systems. Theoretical Computer Science, v. 410, n. 41, p. 4026 – 4043, 2009. ISSN 0304-3975. Festschrift for Mogens Nielsen’s 60th birthday. Dispon´ıvel em: xhttp://www.sciencedirect.com/science/article/ pii/S0304397509004010y.
130 REFER ˆENCIAS BIBLIOGR ´AFICAS
BENEˇs, N. et al. Parametric modal transition systems. In: BULTAN, T.; HSIUNG, P.-A. (Ed.). Automated Technology for Verification and Analysis. Springer Berlin Heidelberg, 2011, (Lecture Notes in Computer Science, v. 6996). p. 275–289. ISBN 978-3-642-24371-4. Dispon´ıvel em: xhttp://dx.doi.org/10.1007/978-3-642-24372-1z 20y.
BENES, N. et al. Parametric modal transition systems. In: BULTAN, T.; HSIUNG, P. (Ed.). Automated Technology for Verification and Analysis, 9th International Symposium, ATVA 2011. Proceedings. Springer, 2011. (LNCS, v. 6996), p. 275–289. ISBN 978-3-642- 24371-4. Dispon´ıvel em: xhttp://dx.doi.org/10.1007/978-3-642-24372-1z 20y.
BENEˇS, N. et al. Refinement checking on parametric modal transition systems. Acta Informatica, v. 52, n. 2, p. 269–297, 2015. ISSN 1432-0525. Dispon´ıvel em: xhttp://dx. doi.org/10.1007/s00236-015-0215-4y.
BENVENISTE, A. et al. Contracts for System Design. [S.l.], 2012. 65 p. Dispon´ıvel em: xhttps://hal.inria.fr/hal-00757488y.
BOEHM, B. Software engineering economics. Software Engineering, IEEE Transactions on, SE-10, n. 1, p. 4–21, Jan 1984. ISSN 0098-5589.
BOZZELLI, L. et al. Refinement modal logic. Information and Computation, Elsevier, v. 239, p. 303–339, 2014.
BROWN, A. W.; WALLNAN, K. C. Engineering of component-based systems. In: IEEE. Engineering of Complex Computer Systems, 1996. Proceedings., Second IEEE Internati- onal Conference on. [S.l.], 1996. p. 414–422.
BRUNET, G. A Characterization of Merging Partial Behavioural Models. Tese (Douto- rado) — University of Toronto, 2006.
BRUNET, G.; CHECHIK, M.; UCHITEL, S. Properties of behavioural model merging. In: MISRA, J.; NIPKOW, T.; SEKERINSKI, E. (Ed.). FM 2006: Formal Methods. Proceedings. Springer, 2006. (LNCS, v. 4085), p. 98–114. ISBN 3-540-37215-6. Dispon´ıvel em: xhttp://dx.doi.org/10.1007/11813040z 8y.
BRUNET, G.; CHECHIK, M.; UCHITEL, S. Properties of behavioural model merging. In: In Proceedings of Formal Methods (FM’06. [S.l.: s.n.], 2006.
BULYCHEV, P.; KONNOV, I.; ZAKHAROV, V. Computing (bi) simulation relations preserving ctl* x. for ordinary and fair kripke structures. –, –, v. 12, 2007.
CHA, S.-H. On complete and size balanced k-ary tree integer sequences. Citeseer. CHATZIELEFTHERIOU, G. et al. Nasa formal methods: 4th international symposium, nfm 2012, norfolk, va, usa, april 3-5, 2012. proceedings. In: . Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. cap. Abstract Model Repair, p. 341–355. ISBN 978-3- 642-28891-3. Dispon´ıvel em: xhttp://dx.doi.org/10.1007/978-3-642-28891-3z 32y.
REFER ˆENCIAS BIBLIOGR ´AFICAS 131
CLARKE, E. M.; GRUMBERG, O.; PELED, D. Model checking. [S.l.]: MIT press, 1999. CLARKE, E. M.; LERDA, F. Model checking: Software and beyond. J. UCS, p. 639–649, 2007.
COCKBURN, A. Agile Software Development. Boston, MA, USA: Addison-Wesley Long- man Publishing Co., Inc., 2002. ISBN 0-201-69969-9.
COHN, M. Succeeding with Agile: Software Development Using Scrum. 1st. ed. [S.l.]: Addison-Wesley Professional, 2009. ISBN 0321579364, 9780321579362.
COURBIS, A.-L. et al. A formal support for incremental behavior specification in agile development. In: Software Engineering and Knowledge Engineering (SEKE). [S.l.: s.n.], 2012. p. 6–p.
D’IPPOLITO, N. et al. MTSA: the modal transition system analyser. In: 23rd IEEE/ACM International Conference on Automated Software Engineering (ASE 2008). IEEE, 2008. p. 475–476. Dispon´ıvel em: xhttp://dx.doi.org/10.1109/ASE.2008.78y. D’IPPOLITO, N. et al. Mtsa: The modal transition system analyser. In: Automated Software Engineering, 2008. ASE 2008. 23rd IEEE/ACM International Conference on. [S.l.: s.n.], 2008. p. 475–476. ISSN 1938-4300.
FAIRBANKS, G. Just enough software architecture: a risk-driven approach. [S.l.]: Marshall & Brainerd, 2010.
FECHER, H.; SCHMIDT, H. Comparing disjunctive modal transition systems with an one-selecting variant. The Journal of Logic and Algebraic Programming, Elsevier, v. 77, n. 1, p. 20–39, 2008.
FISCHBEIN, D.; BRABERMAN, V.; UCHITEL, S. A sound observational semantics for modal transition systems. In: . Theoretical Aspects of Computing - ICTAC 2009: 6th International Colloquium, Kuala Lumpur, Malaysia, August 16-20, 2009. Proceedings. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. p. 215–230. ISBN 978-3-642-03466- 4. Dispon´ıvel em: xhttp://dx.doi.org/10.1007/978-3-642-03466-4z 14y.
FISCHBEIN, D.; UCHITEL, S. On consistency and merge of modal transition systems. In: CITESEER. Proc. of FSE. [S.l.], 2008.
GHEZZI, C. et al. On requirements verification for model refinements. In: Requirements Engineering Conference (RE), 2013 21st IEEE International. [S.l.: s.n.], 2013. p. 62–71. GO, K.; CARROLL, J. M. Scenario-based task analysis. The handbook of task analysis for human-computer interaction, Lawrence Erlbaum Mahwah, NJ, p. 117–133, 2004. GUERRA, P.; ANDRADE, A.; WASSERMANN, R. Toward the revision of ctl models through kripke modal transition systems. In: IYODA, J.; MOURA, L. de (Ed.). Formal
132 REFER ˆENCIAS BIBLIOGR ´AFICAS
Methods: Foundations and Applications. Springer Berlin Heidelberg, 2013, (Lecture No- tes in Computer Science, v. 8195). p. 115–130. ISBN 978-3-642-41070-3. Dispon´ıvel em: xhttp://dx.doi.org/10.1007/978-3-642-41071-0z 9y.
GUERRA, P. T.; ANDRADE, A.; WASSERMANN, R. Toward the revision of CTL models through kripke modal transition systems. In: IYODA, J.; MOURA, L. M. de (Ed.). SBMF 2013. Proceedings. Springer, 2013. (LNCS, v. 8195), p. 115–130. ISBN 978- 3-642-41070-3. Dispon´ıvel em: xhttp://dx.doi.org/10.1007/978-3-642-41071-0z 9y. HUTH, M.; JAGADEESAN, R.; SCHMIDT, D. Modal transition systems: A founda- tion for three-valued program analysis. In: SANDS, D. (Ed.). Programming Languages and Systems. Springer Berlin Heidelberg, 2001, (Lecture Notes in Computer Science, v. 2028). p. 155–169. ISBN 978-3-540-41862-7. Dispon´ıvel em: xhttp://dx.doi.org/10. 1007/3-540-45309-1z 11y.
HUTH, M.; JAGADEESAN, R.; SCHMIDT, D. A. Modal transition systems: A foun- dation for three-valued program analysis. In: SANDS, D. (Ed.). ESOP 2001 - ETAPS 2001, Proceedings. Springer, 2001. (LNCS, v. 2028), p. 155–169. ISBN 3-540-41862-8. Dispon´ıvel em: xhttp://dx.doi.org/10.1007/3-540-45309-1z 11y.
JUHL, L.; LARSEN, K. G. et al. Modal transition systems with weight intervals. The Journal of Logic and Algebraic Programming, Elsevier, v. 81, n. 4, p. 408–421, 2012. KRETINSK. MoTrAs. 2013. ´Ultimo acesso em 17 de Setembro de 2016. Dispon´ıvel em: view-source:https://www7.in.tum.de/ kretinsk/motras.html.
KRKA, I. et al. Synthesizing partial component-level behavior models from system spe- cifications. In: Proceedings of the the 7th Joint Meeting of the European Software Engi- neering Conference and the ACM SIGSOFT Symposium on The Foundations of Software Engineering. New York, NY, USA: ACM, 2009. (ESEC/FSE ’09), p. 305–314. ISBN 978- 1-60558-001-2. Dispon´ıvel em: xhttp://doi.acm.org/10.1145/1595696.1595756y.
KRKA, I. et al. Using dynamic execution traces and program invariants to enhance beha- vioral model inference. In: Software Engineering, 2010 ACM/IEEE 32nd International Conference on. [S.l.: s.n.], 2010. v. 2, p. 179–182. ISSN 0270-5257.
KRKA, I. et al. Revisiting compatibility of input-output modal transition systems. In: JONES, C.; PIHLAJASAARI, P.; SUN, J. (Ed.). FM 2014: Formal Methods. Springer International Publishing, 2014, (Lecture Notes in Computer Science, v. 8442). p. 367–381. ISBN 978-3-319-06409-3. Dispon´ıvel em: xhttp://dx.doi.org/10.1007/978-3-319-06410-9z
26y.
KRKA, I. et al. From system specifications to component behavioral models. In: Soft- ware Engineering - Companion Volume, 2009. ICSE-Companion 2009. 31st International Conference on. [S.l.: s.n.], 2009. p. 315–318.
REFER ˆENCIAS BIBLIOGR ´AFICAS 133
KRKA, I.; MEDVIDOVIC, N. Revisiting modal interface automata. In: Software En- gineering: Rigorous and Agile Approaches (FormSERA), 2012 Formal Methods in. [S.l.: s.n.], 2012. p. 30–36.
KRKA, I.; MEDVIDOVIC, N. Distributing refinements of a system-level partial behavior model. In: Requirements Engineering Conference (RE), 2013 21st IEEE International. [S.l.: s.n.], 2013. p. 72–81.
KRKA, I.; MEDVIDOVIC, N. Component-aware triggered scenarios. 2014 IEEE/IFIP Conference on Software Architecture, IEEE Computer Society, Los Alamitos, CA, USA, v. 0, p. 129–138, 2014.
LARSEN, K.; THOMSEN, B. A modal process logic. In: Logic in Computer Science, 1988. LICS ’88., Proceedings of the Third Annual Symposium on. [S.l.: s.n.], 1988. p. 203–210.
LARSEN, K. G.; NYMAN, U.; WASOWSKI, A. Modal i/o automata for interface and product line theories. In: Proceedings of the 16th European Conference on Programming. Berlin, Heidelberg: Springer-Verlag, 2007. (ESOP’07), p. 64–79. ISBN 978-3-540-71314-2. Dispon´ıvel em: xhttp://dl.acm.org/citation.cfm?id=1762174.1762183y.
LETIER, E. et al. Deriving event-based transition systems from goal-oriented requi- rements models. Automated Software Engg., Kluwer Academic Publishers, Hingham, MA, USA, v. 15, n. 2, p. 175–206, jun. 2008. ISSN 0928-8910. Dispon´ıvel em: xhttp: //dx.doi.org/10.1007/s10515-008-0027-7y.
LUND, M.; STøLEN, K. A fully general operational semantics for uml 2.0 sequence diagrams with potential and mandatory choice. In: MISRA, J.; NIPKOW, T.; SEKE- RINSKI, E. (Ed.). FM 2006: Formal Methods. Springer Berlin Heidelberg, 2006, (Lecture Notes in Computer Science, v. 4085). p. 380–395. ISBN 978-3-540-37215-8. Dispon´ıvel em: xhttp://dx.doi.org/10.1007/11813040z 26y.
LYNCH, N. A.; TUTTLE, M. R. An introduction to input/output automata. CWI Quar- terly, v. 2, p. 219–246, 1989.
MACHADO, E. Z. d. A. KMTS Framework. 2016. ´Ultimo acesso em 27 de Outubro de 2016. Dispon´ıvel em: view-source:https://sourceforge.net/projects/kmtsframework/. MENEZES, M. V. de; BARROS, L. N. de; PEREIRA, S. d. L. Model updating in action. KEPS 2010, p. 29, 2010.
MEOLIC, R.; KAPUS, T.; BREZOVCNIK, Z. Actlw - an action-based computation tree logic with unless operator. Inf. Sci., Elsevier Science Inc., New York, NY, USA, v. 178, n. 6, p. 1542–1557, mar. 2008. ISSN 0020-0255. Dispon´ıvel em: xhttp://dx.doi.org/10. 1016/j.ins.2007.10.023y.
OMG. UML 2.4.1. 2011. ´Ultimo acesso em 30 de Janeiro de 2015. Dispon´ıvel em: view- source:http://www.omg.org/spec/UML/2.4.1/.
134 REFER ˆENCIAS BIBLIOGR ´AFICAS
OMG. OCL 2.4. 2014. ´Ultimo acesso em 30 de Janeiro de 2015. Dispon´ıvel em: view- source:http://www.omg.org/spec/OCL/2.4/.
PARK, D. Concurrency and automata on infinite sequences. In: Theoretical computer science. [S.l.]: Springer, 1981. p. 167–183.
PERRY, D. E.; WOLF, A. L. Foundations for the study of software architecture. SIG- SOFT Softw. Eng. Notes, ACM, New York, NY, USA, v. 17, n. 4, p. 40–52, out. 1992. ISSN 0163-5948. Dispon´ıvel em: xhttp://doi.acm.org/10.1145/141874.141884y.
PRESSMAN, R. S. Software engineering: a practitioner’s approach. [S.l.]: Palgrave Mac- millan, 2005.
RACLET, J.-B. et al. A modal interface theory for component-based design. Fundam. Inf., IOS Press, Amsterdam, The Netherlands, The Netherlands, v. 108, n. 1-2, p. 119–149, jan. 2011. ISSN 0169-2968. Dispon´ıvel em: xhttp://dl.acm.org/citation.cfm? id=2362088.2362095y.
RUNDE, R.; REFSDAL, A.; STøLEN, K. Relating computer systems to sequence dia- grams: the impact of underspecification and inherent nondeterminism. Formal Aspects of Computing, Springer-Verlag, v. 25, n. 2, p. 159–187, 2013. ISSN 0934-5043. Dispon´ıvel em: xhttp://dx.doi.org/10.1007/s00165-011-0192-5y.
SABETZADEH, M.; EASTERBROOK, S. Analysis of inconsistency in graph-based vi- ewpoints: a category-theoretical approach. In: IEEE. Automated Software Engineering, 2003. Proceedings. 18th IEEE International Conference on. [S.l.], 2003. p. 12–21.
SALAY, R. et al. Managing requirements uncertainty with partial models. Requirements Engineering, Springer-Verlag, v. 18, n. 2, p. 107–128, 2013. ISSN 0947-3602. Dispon´ıvel em: xhttp://dx.doi.org/10.1007/s00766-013-0170-yy.
SHOHAM, S.; GRUMBERG, O. A game-based framework for ctl counterexamples and 3-valued abstraction-refinement. ACM Trans. Comput. Logic, ACM, New York, NY, USA, v. 9, n. 1, dez. 2007. ISSN 1529-3785. Dispon´ıvel em: xhttp://doi.acm.org/10. 1145/1297658.1297659y.
SOMMERVILLE, I. Software Engineering. 9th. ed. USA: Addison-Wesley Publishing Company, 2010. ISBN 0137035152, 9780137035151.
SOMMERVILLE, I. Engenharia de Software. 9th. ed. S˜ao Paulo, SP, BR: Pearson Pren- tice Hall, 2011. ISBN 9788579361081.
STIRLING, C. Concur ’95: Concurrency theory: 6th international conference phila- delphia, pa, usa, august 21–24, 1995 proceedings. In: . Berlin, Heidelberg: Springer Berlin Heidelberg, 1995. cap. Local model checking games (extended abstract), p. 1–11. ISBN 978-3-540-44738-2. Dispon´ıvel em: xhttp://dx.doi.org/10.1007/3-540-60218-6z 1y.
REFER ˆENCIAS BIBLIOGR ´AFICAS 135
SUCIU, D.; PAREDAENS, J. Any algorithm in the complex object algebra with powerset needs exponential space to compute transitive closure. In: ACM. Proceedings of the thir- teenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems. [S.l.], 1994. p. 201–209.
SUTCLIFFE, A. G.; RYAN, M. Experience with scram, a scenario requirements analy- sis method. In: Requirements Engineering, 1998. Proceedings. 1998 Third International Conference on. [S.l.: s.n.], 1998. p. 164–171.
THOMAS, W. Tapsoft’93: Theory and practice of software development: 4th internati- onal joint conference caap/fase orsay, france, april 13–17, 1993 proceedings. In: . Berlin, Heidelberg: Springer Berlin Heidelberg, 1993. cap. On the Ehrenfeucht-Fra¨ıss´e game in theoretical computer science, p. 559–568. ISBN 978-3-540-47598-9. Dispon´ıvel em: xhttp://dx.doi.org/10.1007/3-540-56610-4z 89y.
UCHITEL, S. Partial behaviour modelling: Foundations for incremental and iterative model-based software engineering. In: Formal Methods: Foundations and Applications. [S.l.]: Springer, 2009. p. 17–22.
UCHITEL, S.; BRUNET, G.; CHECHIK, M. Synthesis of partial behavior models from properties and scenarios. Software Engineering, IEEE Transactions on, v. 35, n. 3, p. 384–406, May 2009. ISSN 0098-5589.
UCHITEL, S. et al. System architecture: the context for scenario-based model synthesis. In: ACM. ACM SIGSOFT Software Engineering Notes. [S.l.], 2004. v. 29, n. 6, p. 33–42. UCHITEL, S.; KRAMER, J.; MAGEE, J. Synthesis of behavioral models from scenarios. IEEE Trans. Softw. Eng., IEEE Press, Piscataway, NJ, USA, v. 29, n. 2, p. 99–115, fev. 2003. ISSN 0098-5589. Dispon´ıvel em: xhttp://dx.doi.org/10.1109/TSE.2003.1178048y. UCHITEL, S.; KRAMER, J.; MAGEE, J. Synthesis of behavioral models from scenarios. IEEE Trans. Software Eng., v. 29, n. 2, p. 99–115, 2003. Dispon´ıvel em: xhttp://doi. ieeecomputersociety.org/10.1109/TSE.2003.1178048y.
VLIET, H. V.; VLIET, H. V.; VLIET, J. V. Software engineering: principles and practice. [S.l.]: Wiley, 1993.
WANG, F.; CHENG, C.-H. Formal techniques for networked and distributed systems – forte 2008: 28th ifip wg 6.1 international conference tokyo, japan, june 10-13, 2008 pro- ceedings. In: . Berlin, Heidelberg: Springer Berlin Heidelberg, 2008. cap. Program Repair Suggestions from Graphical State-Transition Specifications, p. 185–200. ISBN 978-3-540-68855-6. Dispon´ıvel em: xhttp://dx.doi.org/10.1007/978-3-540-68855-6z 12y. WEI, O.; GURFINKEL, A.; CHECHIK, M. Analysis of of partial modeling formalisms in abstract model checking.
Apˆendice
A
T ´OPICOS DE ENGENHARIA DE SOFTWARE
Neste apˆendice s˜ao abordados os principais t´opicos da engenharia de software relacionados ao tema desta disserta¸c˜ao.
A.1 CEN ´ARIOS
Cen´arios s˜ao descri¸c˜oes de exemplos de sess˜oes de intera¸c˜ao de usu´arios com um sistema (SOMMERVILLE, 2011). Cen´arios s˜ao mais f´aceis de serem entendidos, tanto pelos cli- entes, quanto pelos engenheiros e arquitetos do sistema (UCHITEL; KRAMER; MAGEE, 2003a). Todavia, por representar apenas algumas possibilidades de intera¸c˜ao com o sis- tema, cen´arios s˜ao inerentemente parciais e, por isto, v´arios cen´arios devem ser utilizados para representar todo o comportamento de um sistema. ´E poss´ıvel utilizar cen´arios para detalhar uma descri¸c˜ao geral dos requisitos. Devido a esta facilidade, diversas metodo- logias utilizam cen´arios para elicita¸c˜ao e valida¸c˜ao de requisitos como em (SUTCLIFFE; RYAN, 1998) ou em (GO; CARROLL, 2004). Os cen´arios podem ser expressos de diver- sas maneiras: forma textual, utiliza¸c˜ao de figuras, estruturas condicionais simples (if-else, go to) e atrav´es de diagramas, como ´e o caso do diagrama de sequˆencia da UML.