RWTH Aachen Computer Science V TROPOS Workshop, Trento, November 15-16, 2001 Tropos Research...

RWTH AachenComputer Science V

TROPOS Workshop, Trento, November 15-16, 2001

Tropos Research Overview:

RWTH Aachen M. Jarke and G. Lakemeyer

RWTH Aachen



History of Aachen’s Approach

DAIDA : Metadata linking IS development phases, development of Telos, first ConceptBase prototype (1988)

COMPULOG : logical foundations of meta modeling, meta formula handling by partial evaluation (Jeusfeld 1992)

NATURE/CREWS : application to perspective resolution in requirements engineering and business modeling (Nissen 1997, Peters 1997), extension to business cooperation (Kethers 2001) and warehoues/e-commerce (Quix 2002)

TROPOS : dynamic modeling of social networks in coooperation with sociologists and entrepreneurs



Multi-Perspective Cooperative Modeling : Metamodels as Goals

commonmeta model

entityrelationship

notation

dataflow

notation

viewpoint 2viewpoint 1

common reality

in

For small processes [Nissen et al.; IEEE SW 96]:--> metaplan + repository formalization

For large processes [Rose, CACM 12/98]:--> layout generation + synchronization analysis



Regional Networks in the US

Emilio J. Castilla, Hokyu Hwang, Ellen Granovetter, and Mark Granovetter (2000): Network of Silicon Valley Entrepreneurs



Network Theory Approaches

• Cluster Theory (M. Porter)

• Innovation and productivity by Coopetition

• Social Capital (Bourdieu, Putnam)

• Reputation mechanisms (individual / organisation)

• central role of trust

• our TCD approach (Trust-Confidence-Distrust)

• networks not a hybrid

• distrust is not negation of trust

• successful combination high trust - high distrust !



Local Cluster Information Technology

Entrepreneurship Network Route 128,dependencies according to 40 interviews

50k-Competition

customer

LicensingOffice

Supply/Service

Strategicinvestor

E-Lab

E-Center

Consultant/Mediator

Entrepreneur

Team

AngelAngelGroup

InvestmentBanker

LimitedPartners

VentureCapitalist

lawyer

Faculty Alumni



Modeling Organisation Networks with Tropos: A Trust-Centered Approach

M. Jarke and G. LakemeyerAachen University of Technology

other contributors:

L. Ellrich, C. Funken, M. Meister, Freiburg

G. Gans, S. Kethers, R.Klamma, T. Vits, Aachen

V. Wulf, Fraunhofer FIT



Goal- and Scenario-Based Continuous Requirements Management

animate

capture

initialmodelinitialmodel

newmodelnew

model

existingsystemexistingsystem

newsystem

newsystem

changespecification

reverseanalysis

legacyintegration

changeimplementation

futurescenario

futurescenariocurrent

scenariocurrent

scenario

changeenvisionment

goal/requirementgoal/requirement

refinement/negotiation

scenario generationfor validation/

refinementobservation focus/

goal discovery

... extended to Social Networks



Social Networks

• an autonomous form of coordination that combines advantages of two traditional mechanisms

• markets: flexibility, adaptive to competition

• hierarchies: long duration cooperation

• trusting cooperation of autonomous, but interdependent agents (here: organizations)

• small-business B2B commerce, virtual org‘s

• entrepreneurship networks



Overview

1. Role of Trust/Distrust in Agent Networks

2. A Multi-Perspective Modeling Approach

3. The Tropos(AC) Prototype

4. Conclusions



Trust

expectation of

risky investment reciprocity

• individual trust : likelihood of reciprocity violation

– Coleman: p G > (1-p) L (similar: DAI community)

– game theory: iterated prisoner‘s dilemma

– eBusiness: reputation mechanisms

• network confidence : strategic vulnerabilities, balanced inter-dependency networks

An Example: Seminar Organization

Eric Yu‘s i*,here: the strategic rational model



Distrust• Distrust is not just negation or absence of

trust– Luhmann 1988: functional equivalence + distrust spiral– Kern 1997: inject controlled amount of distrust– Lewicki et al. 1998: high-trust / high-distrust networks

can be highly successful

• Implications for RE– disparity between motive and action (latency)– positive function in networks (watchful trust)– tendency for distrust aggregation must be contained,

e.g. by network rules and traceability (institutionalized distrust)

• A Basis for IT-supported continuous RE !



The TCD Model :a delicate balance for network success



Overview




4. Conclusions



Expectations + Reality

Enhance Viewpoint Resolution Methods: But which Viewpoints are needed?

... communicated in negotiations among

agents

Reaching goals requires certain actions

Speech Acts

Plans

depend on (and influence) Trust, Confidence, Distrust



Multi-Perspective Agent Model:The TCD Kernel



Multi-Perspective Agent Model:Structural Perspectives



Multi-Perspective Agent Model:Action Perspectives

Speech Act Perspektive

Action Workflow [Medina-Mora et al. 1992, Schäl 96]



Delegation within Speech Acts

No trust:

Pro‘s:

Con‘s:

no risk

narrow competence

Speech Act Modeling: TCD influences delegation structure


Trust:

Pro‘s:

Con‘s:

broader competence

delayed reaction

Confidence:

Pro‘s:

Con‘s:

higher risk

improved competence and efficiency


Pro‘s:

Con‘s:

Confidence plus Distrust:

focused risk management

monitoring effort




Extending i* for a Trust-Based Approach

• Task preconditions and postcondition– synchronization of interdependent agent-plans

• Trust, confidence, and distrust as subj. probabilities – as part of preconditions they control task selection

• A simple (linear) model of time– monitoring expectations (distrust, network rules)

Facilitates the mapping into an executable plan language

Organizer´s Plan with Confidence

Client Organizer Speaker

Watchful Confidence



Overview




4. Conclusions



From Extended i* to Congolog programs

proc sem_org <c,l,t.request(c,l,t) /* client c requests seminar l to be held at time t */ if nettrust(c) NWThreshold then (commit(c,l,t); organize(c,l,t)) else /* call a proc. to find speaker first and then commit */ end proc

Example:

Congolog: A logic-based plan language• offers control constructs like sequences, if-then-else, while, recursion, and concurrency

• allows reasoning about actions with a solution to the frame problem (Reiter 1991)• comes equipped with an interpreter for simulation



OMEext. i*

CBaseTCP/IP

static model Telos file

Golog prog. .pl file

Simulator (Java)

Eclipse Golog Int.Java Interf.

History

The System Architecture



start readygo_to_

restaurant

eat

choose_ meal

eating_ finished

rate_ meal

everything_ok

something_ not_ok

good_rating

bad_rating

rate_ good

rate_ bad

meal_ chosen

accept_ order

serve_ meal

cook

order_ received

mealmeal

work

trust_high_ enough

chefwaiterguestexogenous

A Restaurant Domain



guest waiter chefexogenous

The Extended i* Editor OME



/*Agent procedures */

proc(agent_guest,

conc( interrupt(eating_finished=true , decomp_rate_meal),

interrupt(ready=true , decomp_go_to_restaurant))).

proc(agent_chef,interrupt(order_received=true , cook)).

proc(agent_waiter, interrupt(meal_chosen=true , decomp_work)).

/*Decomposition of complex Tasks*/

proc(decomp_work ,[ conc(accept_order , serve_meal), work]).

proc(decomp_go_to_restaurant ,[ conc(choose_meal , eat),

go_to_restaurant]).

proc(decomp_ rate_meal ,[ conc([rate_bad , rate_meal] ,

[rate_good , rate_meal])]).

Congolog Code generated from ext. i*



Simulator 1



Simulator 2



Simulator 3



Conclusions

• worked with sociologists to look into the dynamics of how dependencies and strategic rationals change due to the evolution of trust and distrust in a social network

• Introduced methodology based on i*, ConGolog, and speech acts to model and simulate trust-based inter-actions in agent networks. Have first prototype.

• To evaluate our model, we are studying networks of start-up companies, in Germany and the US (MIT). Also look at b2b applications (M. Schoop, T. List).

• Interested in understanding relationships to other formalizations (model-checking) and applications. Formal joint project?

RWTH Aachen Computer Science V TROPOS Workshop, Trento, November 15-16, 2001 Tropos Research...

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