Modeling and Simulating Software Acquisition Process Architectures

James Choi and Walt ScacchiComputer Science Dept. Institute for Software Research

California State University University of California

Fullerton, CA Irvine, CA

Overview• Software Acquisition

• Modeling Software Process Architectures– A language for modeling processes– Modeling SPAs using the High-Level Architecture

• Simulating Software Process Architectures– A software acquisition process simulator– A testbed for simulating SPAs using the HLA

Software Acquisition

• Multi-enterprise network of processes including software engineering, program and project management, systems integration, deployment and field support.

• Large-scale, long-lived, expensive, and often problematic

Software Acquisition

• Virtual System Acquisition (VISTA--Boehm and Scacchi 1996,1998)

• VISTA suggests the need to integrate and interoperate models and simulations of multiple, distributed software system and software processes

• How to integrate and interoperate multiple, distributed software process simulations

Software Acquisition

• Acquisition process requires factoring and separation of concerns

• => need for software process architectures

• Goal: investigate modeling and simulation of software process architectures for software acquisition

Modeling Software Process Architectures

• Software Process Architecture (SPA):– Software process components whose resource

interfaces are interconnected with connectors, following an overall architectural style.

• A language for modeling processes

• Modeling SPAs using the High-Level Architecture

A language for modeling processesprocess Proposal_Submit {

action submit_proposal {

agent { PrincipalInvestigator }

requires { proposal }

provides { proposal.contents == file }

script {"<p>Submit proposal contents.\

<p>BAA to which this proposal responds: \

<input name='baa' type='string' size=16>\

<br>Proposal title: <input name='title' type='string' size=50>\

<br>Submitting Institution: <input name='institution' type='string' size=25>\

<br>Principle Investigator: <input name='PI' type='string' size=20>\

Email: <input name='PIemail' type='string' size=20>\

<br>Contact: <input name='contact' type='string' size=20>\

Email: <input name='contactEmail' type='string' size=12>\

<br>Proposal contents file: <INPUT NAME='file' TYPE='file'>" } }

Modeling processes using HLA• What is the High-Level Architecture?

– Framework for interoperating independent components integrated with a Run-Time Infrastructure (a global messaging bus)

– Layered, data abstraction, and event-based architectural style supporting publish-subscribe messaging

• HLA is an emerging international standard– 10 framework and interface rules that require use of

the HLA RTI

P1 P2

Pn

C1C2

Cn

Legend:

Pi = Software

Producer process

Ci = Software

Consumer process

Fulfillment Mechanism Connector

Manager

An SPA for Acquisition conforming to the HLA style

Simulating Software Process Architectures

• A software acquisition process simulator

• A testbed for simulating SPAs using the HLA

A software acquisition process simulator

• Software process simulators:– person-in-the-loop software process walkthrough– enables wide-area user participation in software

process design, evaluation and improvement– introduced at ProSim’99 (Scacchi 2000).

• Software acquisition simulator– process simulator for domain of software

acquisition

A testbed for simulating SPAs using the HLA

• Four classes of software acquisition processes– Consumer, Producer, Fulfillment, Manager

– Each runs as a separate simulation (“Federate”) that interoperates (exchanges state info) through the HLA Run-Time Infrastructure (global bus)

– Each simulation supports multiple concurrent instances

– Consumers and Producers exchange requests for, and shipment of, software using the Fulfillment mechanism, as coordinated by the Manager

Discussion

• The run-time environments for PML and HLA are not compatible– An architectural mismatch!

• PML and HLA models of software processes have different run-time semantics

• HLA appears to be ill-suited for use to integrate or interoperate existing software process simulations.

Conclusions

• Demonstrated software process modeling and simulation for software acquisition domain

• Introduced software process architectures

• Evaluated alternative architectures for modeling and simulating SPAs

• Demonstrated distributed and concurrent simulation of multiple interoperating software processes for acquisition