Modelling the Multi-Facetted Purpose of Artefacts

Transcription

1 Modelling the Multi-Facetted Purpose of Artefacts International Workshop On Utility, Usability and Complexity of Emergent IS Colette Rolland Université de Paris1 Sorbonne Namur, December 8-9, 2003

2 Towards Purposeful Systems? The hardest single part of building a software system is deciding precisely what to build - F.Brooks

3 Towards Purposeful Systems? Poor requirements are major source of failures (Standish 95) 8000 projects, 350 US companies : 1/3 of projects never completed & 50% succeeded only partially Most perceived problems are related to requirements specification ( >50%) - (ESI96) : 3800 organisations in 17 European countries

4 Requirements Engineering The WHY question Why the system needs to be developed? The WHAT question What the system shall do? «Requirements definition must say why a system is needed, based on current or foreseen conditions, what system features will satisfy this context,.» (Ross77) IEEE Computer 85, IEEE SE 91-92, Bubenko94, Mylopoulos92, Dardenne93, Loucopoulos95, Rolland98 etc..

5 Requirements Engineering Focusing on the the WHAT question poses problems : Concentrates on the software functionality specification and not enough on its rationale Tackling the WHY question gives hope for more purposeful systems to be developed

6 RE Framework 2 sources of requirements The domain perspective The social perspective SUBJECT WORLD USAGE WORLD System Environment SYSTEM WORLD

7 RE Framework 2 sources of requirements The social perspective System Environment SUBJECT WORLD Understanding the Intentional Relationship is essential to comprehend the system rationale USAGE WORLD Goal driven approaches Intentional Relationship SYSTEM WORLD

8 RE Framework 2 sources of requirements The domain perspective The social perspective System Environment SUBJECT WORLD Domain Genericity relationship Understanding the Domain Genericity Relationship helps eliciting generic requirements USAGE WORLD Intentional relationship SYSTEM WORLD

9 RE Process WHY? Mission statement, goals Goal operationalisation The Requirements Engineering process WHAT? Requirements Specification

10 Goal Driven RE Goals have useful characteristics Goals are optative statements (as opposed to descriptive), (Jackson95), expressions of intents Ex : Transport passengers safely Assure customer loyalty Avoid to deal with details and help focusing of the essentials Goals can be expressed at different level of abstraction Ex : Keep doors close when moving Keep record of loyal customers favourites! Goals drive the elaboration of requirements to support them

11 Goal Driven RE Goals provide rich structuring mechanism (AND/OR refinement) AND Manage lending books Manage borrowership Guarantee borrower privacy Satisfy borrower request Timely Mangt of loan OR Satisfy book request Provide long borrowing period Satisfy bibliography request Maintain as many copies as needed Maintain regular availability

12 Goal Driven RE Goals are roots for conflict detection & resolution Satisfy customer request Satisfy book request Provide long borrowing period Satisfy bibliography request Maintain as many copies as needed Maintain regular availability Conflict!!

13 Goal Driven RE Goals proved to play useful roles in RE requirements elicitation exploration of system choices requirements completeness requirements pre-traceability detection & resolution of conflicts documentation negotiation evolution & change Contributing to the purposefulness of systems

14 Mono-facetted purpose Goal OR AND One single set of requirements (green) shaping one single implemented system functionality : Dealing with a mono-facetted purpose Requirement Rejected alternative

15 Multi-facetted purpose New context of IS product development From meeting the purpose of a single organisation and single set of customers IS products must be conceived to meeting the purpose of different organisations and be adaptable to different usage situations/customer sets ERP systems Product-line development Adaptable software Mergers/take-overs Alignment of business practice in company subsidiaries

16 From goal satisfaction towards goal achievement AND From goal satisfaction Towards goal achievement Goal Ways of achieving Several sets of alternative requirements shaping multiple alternative system functionalities : Dealing with a multi-facetted purpose

17 Modelling the Multi-Facetted Purpose of Artefacts Outline Modelling MFP with maps Refining facets through map refinement Aligning functionality & purpose Customizing MFP

18 Modelling MFP with Maps Map as a set of interconnected A Map is a means to represent a multi-faceted purpose sections <I as a non-deterministic ordering of intentions i, I j, S and ij > having I strategies i as the pre-condition for I j to be I i s ij1 s ij2 I j achieved following S ij Intention A goal to be achieved s i s ji s k s ki I k s jk s s Strategy A manner to achieve an intention An Intention I i together with a Strategy s ki is a Facet

19 Modelling MFP with Maps The ESM Map ERP map to support Electricity Supply Management Competitive Captive Request Credit Advance payment Sell Electricity On customer request By company decision

20 Modelling MFP with Maps Request Credit Advance payment Multi-thread topology Sell Electricity By company decision On customer request Request The multi-thread and multi-path topologies serve to capture multi-faceting : variability with multithread and composite faceting with multi-path Request By company decision Advance payment Sell Electricity On customer request Multi-path topology Credit Sell Electricity

21 Refining facets through map refinement Request Request Competitiv e Credit Captiv e strateg y Credit Advance payment On customer request Sell Electricity Sell Electricity By company decision Refinement allow to look to the A section in a map might multi-facetted nature of a facet. be itself deployed as a map It introduces levels in MFP representation which is fully modelled as a hierarchy of maps Meter Readings by Meter Readers Measure Electricity Comsumption Remote Meter Reading Contract Based On consumption Pay for Electricity Semi Remote Reading Meter Reading By Substation Inspection Recovery

22 Modelling the MFP through a hierarchy of maps The purpose of the artefact is captured in a hierarchy of maps At any given level of the hierarchy, the multi-facetted dimension is based on multi-thread and multi-path topologies Multi-thread introduces local faceting Multi-path introduces global faceting

23 Aligning functionality & purpose Avoiding the «conceptual mistmatch» (Arsajanasi01) Organisation Purpose System Product Functionality

24 Aligning functionality & purpose Relating each section in a map to a functionality component Competitive (C1) Captive (C2) Request Credit (C4) Advance payment (C3) Sell Electricity On customer request (C6) By company decision (C5)

25 Aligning functionality & purpose Reference Competitive (C1) Request Captive (C2) Credit Advance payment (C3) (C4) Sell Electricity Oncustomer request (C6) By company decision (C5) C1 Component Name Customer servicing in a competitive environment Component Interface <(As-Is model, Request with Competitive )> Component Body Provides IT support to - install an IFD to serve customer request - develop customer culture within the company and mesure customer satisfaction - contract customers - market the company

26 Aligning functionality & purpose Reference Competitive (C1) Request Captive (C2) Credit Advance payment (C3) (C4) Sell Electricity Oncustomer request (C6) By company decision (C5) C2 Component Name Customer servicing in a captive environment Component Interface <(As-Is model, Request with Captive )> Component Body Provides IT support to - handle customer requests - keep track of customer complaints - keep track of customers and customer installations information

27 Aligning functionality & purpose Reference Competitive (C1) Request Captive (C2) Credit Advance payment (C3) (C4) Sell Electricity Oncustomer request (C6) By company decision (C5) C4 Component Name Electricity selling in a conventional way Component Interface <(Customer meter Id), Sell Electricity with Credit )> Component Body Provides IT support to manage the process chain of conventional meter reading, electricity consumption billing and payment collection Complex component deployed as a map of components

28 Customizing MFP Organization MFP High level expression Goal- driven Global ERP MFP High level expression Goal- driven Global Abstracting ERP Functionality Descriptions Low level description Function driven Local

29 Customizing MFP ERP Abstraction Step ERP Iteration System MFP Matching Matching Step MFP Organisation MFP Iteration

30 Customizing MFP The Matching Process Model The process for multi-purpose product construction must be itself multi-purpose Abstraction Construct As-Is, To-Be ERP maps ERP driven To-Be driven As-Is driven Feed-back Construct Matched Map To-Be driven verification

31 Customizing MFP Illustrating the Matching Process Customer Visiting Offices Provide Connection Meter Reader Route Based Manual Communication Read Electric Meter Semi Automated Communication Bill Customer Consumption At Company Offices At Private Offices By Post By Bank Collect Transfer Payment On Customer Request On Company Decision As-Is Map of the ESM Case Study

32 Customizing MFP Illustrating The Matching Process Introduce Customer Culture Employees Retraining Compete for Customer Keep Customer Loyalty Improve means to serve Introduce means to serve eligible customer Break Relationship non eligible customer Break Relationship The ESM To-Be Map

33 Customizing MFP Building the Matched Map Employees Retraining Introduce Customer Culture Keep Customer Loyalty Compete for Customer Improve means to serve noneligible customer Break Relationship To-Be Improve means to serve eligible customer Break Relationship Competitive Request Credit Captive Advance payment Sell Electricity ERP On customer request By company decision Competitive Captive Request

34 Customizing MFP Building the Matched Map Introduce Customer Culture Employees Retraining Compete for Customer Introduce Customer Culture Keep Request Customer Loalty Improve means to serve noneligible customer Break Relationship To-Be Improve means to serve eligible customer Break Relationship Competitive Request Credit Captive Advance payment Sell Electricity ERP On customer request By company decision Marketing Change Culture Contracting Request Marketing Change Culture Contracting Intelligent Front Desk (IFD )

35 Customizing MFP Building the Matched Map Introduce Customer Culture Employees Retraining Compete for Customer Introduce Customer Culture Keep Request Customer Loalty Improve means to serve noneligible customer Break Relationship To-Be Improve means to serve eligible customer Break Relationship Competitive Request Credit Captive Advance payment Sell Electricity ERP On customer request By company decision IFD at Company Marketing Change Culture Premises Contracting IFD at Customer Premises Marketing Change Culture Request Contracting Intelligent Front Desk (IFD )

36 Customizing MFP Building the Matched Map Employees Retraining Introduce Customer Culture Keep Customer Loyalty Compete for Customer Improve means to serve noneligible customer Break Relationship To-Be Improve means to serve eligible customer Break Relationship On customer request Competitive Advance Request payment Credit Captive Credit Request Sell Electricity Sell ERP By company decision IFD at Company Marketing Change Culture Premises Contracting IFD at Customer Premises Request Measure Electricity Comsumption Pay for Electricity Meter Readings by Meter Readers Mesure Electricity Comsumption On consumption Remote Meter Reading Semi Remote Reading Integrated Map Meter Reading By Substation Inspection Contract Based Recovery Pay for Electricity

37 Customizing MFP Building the Matched Map Employees Retraining Introduce Customer Culture Keep Customer Loyalty Compete for Customer Improve means to serve noneligible customer Break Relationship To-Be Improve means to serve eligible customer Break Relationship On customer request Competitive Advance Request payment Credit Captive Credit Request Sell Electricity Sell ERP By company decision IFD at Company Marketing Change Culture Premises Contracting IFD at Customer Premises Request Remote Meter Reading Measure Electricity Comsumption On Customer Appointment Based Contract Based consumption Pay for Electricity Meter Readings by Meter Readers Mesure Electricity Comsumption On consumption Remote Meter Reading Semi Remote Reading Meter Reading By Substation Inspection Contract Based Recovery Pay for Electricity

38 Customizing MFP As-Is Customer Visiting At Company Offices Bill Customer Offices Provide Consumption Connection Manual Communication At Privates Offices Meter Reader By Post Route Based By Bank Collect Read Electric Collect Meter Transfer Payment On On Company On Semi Automated On Customer Decision Communication Request Remote Meter Reading Employees Retraining Introduce Customer Culture Keep Customer Loyalty Measure Electricity Comsumption On Compete for Customer Improve means to serve noneligible customer Break Relationship Customer Appointment Based Contract Based consumption To-Be Improve means to serve eligible customer Break Relationship Company Decision IFD at Company Marketing Change Culture Premises Contracting IFD at Customer Premises Request On customer request Competitive On Advance customer Request payment request On Company Decision Pay for Electricity Credit Captive Sell Electricity On Customer Request ERP Bycompany decision By company decision

39 Bye Bye François!