1. S CHOOL OF I NFORMATION T ECHNOLOGY AND E NGINEERING U NIVERSITY OF O TTAWA, C ANADA Daniel Amyot Q18/17 (URN) Rapporteur damyot@site.uottawa.ca User Requirements Notation (URN )

2. Workshop on "Framework and scope of formal languages", Geneva, March 2, 20022 Objectives n Brief overview of URN n Goal-oriented Requirement Language (GRL), Use Case Maps (UCMs), and their relationships n Connections between URN and several languages from ITU and OMG n Several Challenges

3. Workshop on "Framework and scope of formal languages", Geneva, March 2, 20023 n Need improvement to cope with new realities of complex, dynamic, and evolving systems n Common design and standardisation methodologies already use scenarios Requirements and Service Description Stage 1 Message Sequence Information Stage 2 Protocols, Procedures, Behaviour Stage 3 SDL or UML Statechart diagrams MSC or UML interaction diagrams Informal requirements? Use Cases? URN! Motivation for URN

4. Workshop on "Framework and scope of formal languages", Geneva, March 2, 20024 URN - Initial Objectives n Focus on early stages of design, with scenarios n Capture user requirements when little design detail is available n No messages, components, or component states required n Reusability of scenarios and allocation to components n Dynamic refinement capabilities n Modelling of agent systems, early performance analysis, and early detection of undesirable interactions

5. Workshop on "Framework and scope of formal languages", Geneva, March 2, 20025 URN - Additional Objectives n Express, analyse and deal with non- functional requirements (NFRs) n Express the relationship between business objectives/goals and system requirements n Capture reusable analysis (argumentation) and design knowledge (patterns) for addressing non-functional requirements n Connect to other ITU-T languages (and to UML)

6. Workshop on "Framework and scope of formal languages", Geneva, March 2, 20026 Current Proposal for URN n Draft documents for Z.150, Z.151, Z.152 –http://www.UseCaseMaps.org/urn/ n Combined use of two complementary notations: –Goal-oriented Requirement Language (GRL) for NFRs (http://www.cs.toronto.edu/km/GRL/) –Use Case Maps (UCM) for Functional Requirements (http://www.UseCaseMaps.org/) n Create ITU-T standard by end of 2003 (Z.150-153)

7. Workshop on "Framework and scope of formal languages", Geneva, March 2, 20027 GRL in a Nutshell n Goal-oriented Requirement Language — a graphical notation that allows reasoning about (non-functional) requirements n GRL is concerned with intentional elements, actors, and their relationships n Intentional elements model the “why” aspect — objectives, alternatives, as well as decision rationale and criteria — but not operational details n GRL satisfies most of URN’s additional objectives

8. Workshop on "Framework and scope of formal languages", Geneva, March 2, 20028 Basic GRL Notation Means-End PasswordCardkeyBiometrics Correlation (side-effect) Cost of Terminal Belief Argumentation Biometrics is no regular off-the-shelf technology Goal Decomposition (AND) IdentificationAuthentication Task Make.. Contribution Softgoal Access Authorization Encryption Security of Host Security of Terminal System Security

9. Workshop on "Framework and scope of formal languages", Geneva, March 2, 20029 Evaluations with GRL.. PasswordCardkeyBiometrics Identification Cost of Terminal Biometrics is no regular off-the-shelf technology Access Authorization Encryption Authentication Satisficed Weakly Satisficed Undecided Weakly Denied Denied Security of Host Security of Terminal System Security

10. Workshop on "Framework and scope of formal languages", Geneva, March 2, 200210 UCMs in a Nutshell n Use Case Maps – a graphical scenario notation for describing causal relationships between responsibilities n Scenario elements may (optionally) be linked to components n The intent of UCMs is to facilitate the integration and reusability of scenarios, and to guide the design of high level architectures and detailed scenarios from requirements n UCMs satisfy most initial URN requirements

11. Workshop on "Framework and scope of formal languages", Geneva, March 2, 200211 Component Start Point End Point Responsibility Stub AND-Fork Pool a) Root UCM Slot b) Biometrics Plug-In c) PassWord Plug-in Timer OR-Fork

12. Workshop on "Framework and scope of formal languages", Geneva, March 2, 200212 GRL - UCM Relationship n Goal-based approach –Focuses on answering “why” questions –Addresses functional and non-functional requirements n Scenario-based approach –Focuses on answering “what” questions n Goals are operationalized into tasks and tasks are elaborated in (mapped to) UCM scenarios –Focuses on answering “how” questions

13. Workshop on "Framework and scope of formal languages", Geneva, March 2, 200213 From UCM Requirements to More Detailed Design Models n Requires: –Path Data Model (global Booleans variables) –Scenario Definitions –Path Traversal Mechanism –Mapping Rules (MSC, UML, TTCN, LQN, LOTOS...)

14. Workshop on "Framework and scope of formal languages", Geneva, March 2, 200214 Informal Requirements, Textual Use Cases URN — OMG/SG17 Puzzle UCMs link to operationalizations (tasks) in GRL models Structural Diagrams SDL, ODL, or UML Class, Object, Component, & Deployment Diagrams Testing and Performance Languages TTCN, LQN,... Behavioral Diagrams MSC/SDL, or UML Sequence, Collabor., & Statechart Diagrams UCMs represent visually use cases in terms of causal responsibilities UCMs provide a framework for making high level and detailed design decisions UCMs visually associate behavior with structure at the system level ? ? UML Use Case Diagram & Activity Diagram URN-NFR/GRL Goals, non-functional requirements, alterna- tives, rationales URN-FR / UCMs Superimpose visually system level behavior onto structures of abstract components

15. Workshop on "Framework and scope of formal languages", Geneva, March 2, 200215 Several Challenges (I) n Degree of formalisation –Qualitative/quantitative GRL evaluations? –UCM path traversal algorithms? –Reasoning in presence of looseness, incompleteness, inconsistencies? n Formalisation of languages –BNF? Graphical grammar? XML & schemas? –Layout information?

16. Workshop on "Framework and scope of formal languages", Geneva, March 2, 200216 Several Challenges (II) n Extensibility and Adaptability –UML Profiles? n Connections to other languages –Traceability, transformations, meta-model? n Methodologies –What subsets of languages make sense together? –Do methodologies drive the evolution of standard languages? –Who are the stakeholders?

17. Workshop on "Framework and scope of formal languages", Geneva, March 2, 200217 Main References n http://www.UseCaseMaps.org/urn/ n Amyot, D. and Logrippo, L., Use Case Maps and L OTOS for the Prototyping and Validation of a Mobile Group Call System, In:Computer Communications 23(8), 2000. n Amyot, D. and Mussbacher, G., On the Extension of UML with Use Case Maps Concepts, UML2000, York, UK, October 2000. n Buhr, R.J.A., Use Case Maps as Architectural Entities for Complex Systems, In: Transactions on Software Engineering, IEEE, Vol. 24, No. 12, December 1998, pp. 1131- 1155. n Chung, L., Nixon, B.A., Yu, E. and Mylopoulos, J., Non-Functional Requirements in Software Engineering. Kluwer Academic Publishers, 2000. n Liu, L. and Yu, E., From Requirements to Architectural Design – Using Goals and Scenarios, In: From Software Requirements to Architectures Workshop (STRAW 2001), Toronto, Canada, May 2001. n Miga, A., Amyot, D., Bordeleau, F., Cameron, D., and Woodside, M., Deriving Message Sequence Charts from Use Case Maps Scenario Specifications, 10 th SDL Forum, Copenhagen, Denmark, June 2001. n Monkewich, O., Sales, I., and Probert, R., OSPF Efficient LSA Refreshment Function in SDL, 10 th SDL Forum, Copenhagen, Denmark, June 2001. n Scratchley, W.C., Evaluation and Diagnosis of Concurrency Architectures, Ph.D. thesis, Carleton University, Canada, November 2000.