S CHOOL OF I NFORMATION T ECHNOLOGY AND E NGINEERING U NIVERSITY OF O TTAWA, C ANADA Daniel Amyot Q.18/17 Rapporteur SITE, University of Ottawa, Canada Using the User Requirements Notation ITU-T Workshop on the "Use of Description Techniques"

URN, ITU-T Workshop on the "Use of Description Techniques", November 23, About this presentation n What is the User Requirements Notation (URN)? n What can we model with URN? n What answers can these models provide? n What are the typical/potential usages?

URN, ITU-T Workshop on the "Use of Description Techniques", November 23, URN – Main objectives n Focus on early stages of development with goals and scenarios n From user requirements to system functional and non-functional requirements n No messages, components, or component states required n Reusability –of argumentations (goal patterns and analysis) –of scenarios (patterns and architectural alternatives) n Early performance analysis n Traceability and transformations to other languages –Particularly MSC, SDL, TTCN, and UML

URN, ITU-T Workshop on the "Use of Description Techniques", November 23, Current Proposal for URN n Draft documents for Z.150, Z.151, Z.152 n Combined use of two complementary notations: –Goal-oriented Requirement Language (GRL) for NFRs ( –Use Case Maps (UCM) for Functional Requirements ( n Create ITU-T standard by end of 2003 n

URN, ITU-T Workshop on the "Use of Description Techniques", November 23, ? ? MSC, UML Use Case Diagram & Activity Diagram Informal Requirements, Textual Use Cases URN — Missing Piece of the Modelling Puzzle? UCMs link to operationalizations (tasks) in GRL models Structural Diagrams SDL, eODL, 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 and structure at the system level URN-FR / UCMs Superimpose visually system level behavior onto structures of abstract components. Can replace UML use case & deployment diagams. URN-NFR/GRL Goals, non-functional requirements, alterna- tives, rationales Data ASN.1 where appropriate

URN, ITU-T Workshop on the "Use of Description Techniques", November 23, GRL in a Nutshell n Goal-oriented Requirement Language –graphical notation –connects requirements of requirements to business objectives –allows reasoning about (non-functional) requirements n GRL models the “why” aspect –objectives, alternatives, as well as decision rationale –no operational details n Supports goal analysis and evaluations

URN, ITU-T Workshop on the "Use of Description Techniques", November 23, 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.. Access Authorization Encryption ? BreakHurtSome- Unknown MakeHelpSome+Equal Contribution Security of Host Security of Terminal Softgoal System Security

URN, ITU-T Workshop on the "Use of Description Techniques", November 23, 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

URN, ITU-T Workshop on the "Use of Description Techniques", November 23, UCMs in a Nutshell n Use Case Maps –graphical scenario notation –causal relationships between responsibilities –scenario elements may (optionally) be allocated to components n UCMs model the “what” aspects –functional requirements as scenarios –integration and reusability of scenarios –guidance for architecture and detailed behaviour n Performance analysis, conflict detection

URN, ITU-T Workshop on the "Use of Description Techniques", November 23, 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

URN, ITU-T Workshop on the "Use of Description Techniques", November 23, GRL - UCM Relationship n Goal-based approach –Focuses on answering “why” questions 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 n GRL goals can guide the selection of a particular architecture for the UCM scenarios

URN, ITU-T Workshop on the "Use of Description Techniques", November 23, Typical Usage of URN n Modelling and documentation –User and system requirements, rationales n Analysis of business goals –Evaluations of alternative requirements or solutions –Discovery of tradeoffs that can optimize the stakeholders’ degree of satisfaction for conflicting goals n Architecture analysis –Based on NFRs and design constraints –Performance analysis n Generation of individual scenarios –Training, documentation –Detection of conflicts –Transformation to MSC and test cases n Reverse-engineering

URN, ITU-T Workshop on the "Use of Description Techniques", November 23, Experiences with GRL n Used on industrial projects –New family of Web-based telephone sets –Documentation of discussions involving multiple stakeholders –Visualization and analysis of conflicting goals –Evaluation of architectural solutions, and rationales for the retained solution –Proved to be very helpful for keeping discussions on track and for avoiding repeating the same discussions over and over again. –Accelerated the reaching of an agreement and –Improved (short-term and long-term) understanding. n Used in academic projects –Security applications –Web-based systems (in combination with UCMs) –Architectural/performance tradeoffs at a qualitative level

URN, ITU-T Workshop on the "Use of Description Techniques", November 23, Performance Engineering with UCMs Response Time Requirement From T1 to T2 Name Response time Percentage SecurityE_Accountant Ready Continue CheckBio TaxPayer Access T1 Timestamp T2 Device Characteristics Processors, disks, DSP, external services… Speed factors Rejected Arrival Characteristics Exponential, or Deterministic, or Uniform, or Erlang, or Other Population size Responsibilities Data access modes Device demand parameters Mean CPU load (time) Mean operations on other devices OR Forks Relative weights (probability) Components Allocated responsibilities Processor assignment Automated translation to Layered Queuing Networks (LQNs), for analytical evaluations and simulations. Being applied to industrial case studies.

URN, ITU-T Workshop on the "Use of Description Techniques", November 23, UCM Scenario Definitions and Path Traversal (Highlight) n Extraction of individual scenarios n Conditions attached to selection points n Initialization of Boolean variables, and selection of start points

URN, ITU-T Workshop on the "Use of Description Techniques", November 23, Tool Support: UCMNav 2.1

URN, ITU-T Workshop on the "Use of Description Techniques", November 23, 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...)

URN, ITU-T Workshop on the "Use of Description Techniques", November 23, ICS invocation with Normal Termination and Distinctive Alerting Experiences with TIA’s Wireless Intelligent Network

URN, ITU-T Workshop on the "Use of Description Techniques", November 23, IncomingCall (IC) CallSetup (CS) CallBlocked (CB) Screening (S) NormalAlerting (NA) PlayBlockAnnounce (PBA) Simplified UCM for Incoming Call Screening WIN Phase 1 covers three major services: Calling Name Presentation (CNAP) Incoming Call Screening (ICS) Voice Controlled Services (VCS) The following ICS Use Case Map is for illustration purpose.

URN, ITU-T Workshop on the "Use of Description Techniques", November 23, FE1 FE5 FE6 FE1 FE2 FE3 FE4 FE1 FE2 (a) First Structure(b) Second Structure(c) Different Mapping of UCM FE3 FE4 CS S IC CB PBA NA CS IC CB PBA NA S IC S CB PBA CS NA Incoming Call Screening Scenario on Functional Entities

URN, ITU-T Workshop on the "Use of Description Techniques", November 23, NE1 FE1 NE3 FE3 NE2 FE2 NE4 FE4 NE1 FE1 NE3 FE3 NE2 FE2 FE4 NE1 FE1 NE3 FE2 (a) First Structure(b) Second Structure(c) Different Mapping of FEs NE2 FE3 FE4 Binding Functional Entities to Network Entities

URN, ITU-T Workshop on the "Use of Description Techniques", November 23, NE1 FE1 NE3 FE2 NE2 FE3 FE4 CS S IC (a) UCM to FEs to NEs CB PBA NA NE1NE2NE3 IC CS m2 m1 NE1NE2NE3 CB IC m2 m1 m4 (b) A MSC for (c) A MSC for m3 m5 S NA S PBA Refinement with MSC

URN, ITU-T Workshop on the "Use of Description Techniques", November 23, CallBlocked Announcement Plug-in UCM for ICS

URN, ITU-T Workshop on the "Use of Description Techniques", November 23, Coming soon… n URN-oriented Reverse-Engineering –UCMs for reverse-engineering already popular. –Can cope with very complex systems n UCM to UML scenarios n UCM to TTCN test cases n URN and Requirements Management n UCM and Requirements-based Design (synthesis) –Already a tool-support mapping to LOTOS

URN, ITU-T Workshop on the "Use of Description Techniques", November 23, Conclusions n URN –Allows engineers to specify or discover requirements for a proposed system or an evolving system, and review such requirements for correctness and completeness. –Is usable in industry and in standardization bodies –Combines goals and scenarios –Helps bridging the gap between informal and formal concepts, and between requirements models and design models –Big benefits for little modelling investment, even when used informally n GRL –For incomplete, tentative, (non-functional) requirements –Capture goals, objectives, alternatives and rationales n UCM –For operational and functional requirements –Enables analysis and transformations –Architectural alternatives and dynamic systems

URN, ITU-T Workshop on the "Use of Description Techniques", November 23, th Feature Interaction Workshop Ottawa, June 9-11, Submission deadline: December 9