Technical Reports
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USC-CSE-2003-520 PDF Composable Process
Elements for Developing COTS-Based Applications Barry
Boehm, Data
collected from five years of developing e-service applications at USC-CSE
reveals that an increasing fraction have been commercial-off-the-shelf
(COTS)-Based Application (CBA) projects: from 28% in 1997 to 60% in 2001.
Data from both small and large CBA projects show that CBA effort is primarily
distributed among the three activities of COTS assessment, COTS tailoring,
and glue code development and integration, with wide variations in their
distribution across projects. We have developed a set of data-motivated composable process elements, in terms of these three
activities, for developing
CBA's as well an overall decision framework for
applying the process elements. We present data regarding the movement towards
CBA's and effort distribution among them; we then
proceed to describe the decision framework and to present a real-world example
showing how it operates within the WinWin Spiral
process model generator to orchestrate, execute, and adapt the process
elements to changing project circumstances. Document characteristics: Proceedings,
ISESE 2003, September/October 2003 Added: June 24, 2004 USC-CSE-2003-519 PDF Reasoning About the Value of Dependability: The iDave Model Barry
Boehm, LiGuo Huang, Apurva
Jain In
this paper, we present a framework for reasoning about the value of
information processing dependability investments called the Information
Dependability Attribute Value Enhancement (iDAVE)
model. We describe the overall structure of iDAVE,
and illustrate its use in determining the ROI of investments in dependability
for a commercial order processing system. We conclude that dynamic and
adaptive value-based dependability mechanisms such as iDAVE
model will become increasingly important provided evidence that dependability
attribute requirement levels tend to be more emergent than pre-specifiable. Document characteristics: EDSER-5
Proceedings, May 2003. Added: June 24, 2004 USC-CSE-2003-518 PDF Agility Through Discipline: A Debate Barry Boehm, and Kent Beck view the world in “both-and”
terms instead of “either-or” terms. Why this disconnect? Document characteristics: Computer,
June 2003, pp. 44-46. Added: June 24, 2004 USC-CSE-2003-517 PDF People Factors in Software Management: Lessons From Comparing Agile and Plan-Driven Methods Barry Boehm, and Richard Turner While
methodologies, management techniques, and technical approaches are valuable,
a study of agile and plan-driven approaches has confirmed that the most
critical success factors are much more likely to be in the realm of people
factors. This paper discusses five areas where people issues can have a
significant impact: staffing, culture, values, communications, and
expectations management. Document characteristics: Added: USC-CSE-2003-516 Calculating
Architectural Reliability via Modeling and Analysis (Qualification Exam
Report)
Roshanak
Roshandel Modeling and estimating software
reliability during testing is useful in quantifying the quality and
dependability of the developed software systems. However, such measurements
applied so late in the development process leave little to be done to improve
the quality of the software system in a cost-effective way. Reliability, an
important dependability attribute, is defined as the probability that the
system performs its intended functionality under specified design limits. We argue
that reliability models must be built to estimate the system reliability
throughout the development process, and specifically when exact context and
execution profile of the system may be unknown, or when the implementation
artifacts are not yet available. In the context of software architectures,
various techniques for modeling software systems and specifying their
functional properties have been developed. These techniques enable extensive
analysis of the specification, but typically lack quantification.
Additionally, their relation to dependability attributes of the modelled software system is unknown. In this proposal, we present a software
architecture-based approach to estimating system reliability. The approach is
applicable to early stages of development when the implementation artifacts
are not yet available, and exact execution profile is unknown. The
uncertainty of the execution profile is modeled using stochastic processes
with unknown parameters. The approach is compositional in nature: the overall
reliability of the system is estimated as a function of the reliability of
its constituent components and their (complex) interactions. In turn, the
reliability of individual components is estimated using standard modeling and
specification mechanisms of software architectures. Additionally, sensitivity
analyses enabled by our reliability model prescribe defect mitigation
strategies in a cost-effective manner. Document characteristics: Added: USC-CSE-2003-515 PDF Improving
Availability in Large, Distributed, Component-Based Systems via Redeployment Marija Mikic-Rakic, Sam Malek, Nenad Medvidovic In
distributed and mobile environments, the connections among the hosts on which
a software system is running are often unstable. As a result of connectivity
losses, the overall availability of the system decreases. The distribution of
software components onto hardware nodes (i.e., the system’s deployment
architecture) may be ill-suited for the given target hardware environment and
may need to be altered to improve the software system’s availability.
The critical difficulty in achieving this task lies in the fact that
determining a software system’s deployment that will maximize its availability
is an exponentially complex problem. In this paper, we present a fast approximative solution for this problem, and assess its
performance. Document characteristics: Added: December 15, 2003 USC-CSE-2003-514 PDF Alfa: A Framework
for Composing Software Architectures from Architectural Primitives Nikunj R. Mehta and Nenad
Medvidovic Architectural styles represent
composition patterns and constraints at the software architectural level and are
targeted at families of systems with shared characteristics. They enable
architectural reuse and hence can bring economy to architecture-based
software development. Existing research on architectural styles provides
little guidance for the systematic design and construction of architectural
style elements. This paper proposes a framework, Alfa, for systematically and
constructively composing “architectural primitives” to obtain
elements of architectural styles. This is based on our observation that architectural
styles and, indeed, software architectures share many underlying concepts
that lead to architectural primitives. We have identified eight forms and
nine functions as architectural primitives that reflect the syntactic and
semantic characteristics of software architectures and are expressive enough
to compose elements of architectural styles used in modern, distributed
systems. Such an approach enables systematic construction of style-based
architectures. In that direction, this paper evaluates the suitability of
Alfa as an assembly language for software architectures and its suitability
for composing architectural styles for network-based systems. Document characteristics: Added: November 25, 2003 USC-CSE-2003-513 PDF The Schedule as Independent Variable (SAIV) Process for Acquisition of Software-Intensive Systems Barry Boehm, Winsor
Brown, LiGuo Huang, and Many system
acquisitions do not achieve on-time delivery because of delays in software
development. This paper presents a highly successful approach for on-time
delivery of software-intensive systems: the Schedule As Independent Variable
(SAIV) process. The SAIV process involves prioritization of desired features;
scoping a Core Capability of top-priority features easily achievable within
the available schedule; architecting for ease of dropping or adding
borderline-priority features; monitoring progress with respect to plans; and
adding or dropping borderline-priority features to meet the schedule target.
The paper summarizes experiences and discusses critical success factors in
applying the SAIV acquisition process across a range from small in-house
e-services projects to very large Government systems of systems. Document characteristics: Added: November 19, 2003 USC-CSE-2003-510 PDF Concise
Composition of Architectural Styles From Architectural Primitives Nikunj R. Mehta, Nenad Medvidovic Architectural
styles represent composition patterns and constraints at the software
architectural level and are targeted at families of systems with shared
characteristics. They enable architectural reuse and hence can bring economy
to the design of software architecture. Existing approaches support
systematic description of style-based software architectures. Our approach,
Alfa, focuses on the construction, instead of description, of style-based
software architectures using architectural primitives. This is based on our
observation that architectural styles and, indeed, software architectures
share many underlying concepts that lead to architectural primitives.
Previously, Alfa’s primitives were shown to be sufficient for modeling
architectural styles. In this paper, we present the composition of a diverse
set of styles for network-based systems using xAlfa,
a systematic notation for composing styles from Alfa’s primitives. We
then show that two reuse mechanisms in xAlfa,
inheritance and composition, enable concise style compositions and
unambiguously bring out similarities among architectural styles. Document characteristics: Updated: October 30, 2003 USC-CSE-2003-509 PDF Effective
Modeling of Software Architectural Assemblies Using Constraint Automata Nikunj R. Mehta, Marjan
Sirjani, Farhad Arbab Alfa is a
framework for the construction of software architectures and their elements
from architectural primitives. In any system involving events from multiple
sources, synchrony and asynchrony between events arise naturally. Support for
simultaneous synchrony and asynchrony, and
scalability to assemblies of large numbers of architectural primitives are
central concerns for effectively modeling software architectural assemblies in
Alfa. An increasingly popular formalism for event-based modeling of the
behavior of software architectures, labeled transition systems (LTS), was
initially chosen to model the behavior of Alfa assemblies. However, this
creates an impedance mismatch with the architect’s mental model and
lacks sufficient scalability. We therefore propose a formal approach to
effectively model software architectural assemblies that addresses these
limitations, using constraint automata. Constraint automata can be mapped to
LTS thus utilizing existing techniques for analysis of behavioral properties.
We evaluate the effectiveness of our approach using two application
architectures assembled from Alfa’s primitives. Document characteristics: Updated: September 25, 2003 USC-CSE-2003-508 PDF Using Multiple Views to Model and Analyze Software Architecture: An
Experience Report Roshanak Roshandel, Bradley Schmerl,
Nenad Medvidovic, David Garlan, Dehua Zhang Architectural
modeling and analysis is a critical phase in developing large and complex
software systems. The usefulness of multiple views has likewise long been
recognized. In this experience report, we explain how we used two ADLs to model a system initially described in UML. The
system SCRover) is designed and built in close
collaboration with NASA’s Jet Propulsion Laboratory, using their Document characteristics: Updated: September 18, 2003 USC-CSE-2003-507 PDF Using Testbeds to Accelerate Technology Maturity and
Transition: The SCRover Experience Barry Boehm, Jesal
Bhuta, David Garlan, Eric
Gradman, LiGuo Huang, Alexander Lam, Ray Madachy, Nenad Medvidovic, Kenneth Meyer, Steven Meyers, Gustavo Perez, Kirk Reinholtz,
Roshanak Roshandel, Nicolas Rouquette This
paper is an experience report on a first attempt to develop and apply a new
form of software: a full service testbed designed
to evaluate alternative software dependability technologies, and to
accelerate their maturation and transition into project use. The SCRover testbed includes not
only the specifications, code, and hardware of a public safety robot, but
also the package of instrumentation, scenario drivers, seeded defects,
experimentation guidelines, and comparative effort and defect data needed to
facilitate technology evaluation experiments. The
SCRover testbed’s
initial operational capability has been recently applied to evaluate two
architecture definition languages (ADLs) and
toolsets, Mae and AcmeStudio. The testbed evaluation showed (1) that the ADL-based toolsets
were complementary and cost effective to apply to mission-critical systems;
(2) that the testbed was cost-effective to use by
researchers; and (3) that collaboration in testbed
use by researchers and the Jet Propulsion Laboratory (JPL) project users
resulted in actions to accelerate technology maturity and transition into
project use. The evaluation also identified a number of lessons learned for
improving the SCRover testbed,
and for development and application of future technology evaluation testbeds. Document characteristics: Updated: September 18, 2003 USC-CSE-2003-506 PDF Software Architectural Support for
Disconnected Operation in Highly Distributed Environments Marija Mikic-Rakic, and Nenad
Medvidovic
In distributed and mobile environments,
the connections among the hosts on which a software system is running are
often unstable. As a result of connectivity losses, the overall availability
of the system decreases. The distribution of software components onto
hardware nodes (i.e., deployment architecture) may be ill-suited for the
given target hardware environment and may need to be altered to improve the
software system's availability. The critical difficulty in achieving this
task lies in the fact that determining a software system's deployment that
will maximize its availability is an exponentially complex problem. In this
paper, we present an automated, flexible, software architecture-based
solution for disconnected operation that increases the availability of the
system during disconnection. We provide a fast approximative
solution for the exponentially complex redeployment problem, and assess its
performance. Document characteristics:
Submitted to ICDCS 2004. Updated: September 17, 2003 USC-CSE-2003-505 PDF Value-Based
Software Engineering: A Case Study Barry Boehm and Li Guo
Huang
The value-based approach to
software development integrates value considerations into current and emerging
software engineering principles and practices, while developing an overall
framework in which these techniques compatibly reinforce each other. Document characteristics:
Published at IEEE Computer, March 2003, Vol. 36, No. 3. Updated: April 26, 2003 USC-CSE-2003-504 PDF Relating
Software Component Models Roshanak Roshandel, and Nenad
Medvidovic
A software component is typically modeled at one or
more of four levels: interface, static behavior, dynamic behavior, and
interaction protocol. Each of these levels helps to ensure different aspects
of component compatibility and interoperability. Existing approaches to
component modeling have either focused on only one of the levels (e.g.,
interfaces in various IDLs) or on well-understood
combinations of two of the levels (e.g., interfaces and their associated pre-
and post-conditions in static behavioral modeling approaches). This paper
argues that, in order to accrue the true benefits of component-based software
development, one may need to model components at all four levels. Before that
can be possible, one needs to understand the relationships among the
different models. We detail one such pair-wise relationship—between
static and dynamic component models—and draw parallels between it and
the remaining models. Document characteristics: added: March 26, 2003 USC-CSE-2003-503 PDF Composing
Architectural Styles From Architectural Primitives Nikunj Mehta, and Nenad Medvidovic
Architectural styles are named collections of constraints on
configurations of architectural elements, and are believed to bring economies
of scale in applying software architecture techniques to software
development. Most research on architectural styles focuses on analyzing and
observing the properties of such styles from their descriptions. However,
comparatively little is known about the systematic design and construction of
software architectures using architectural styles. Existing classifications
bring out differences between architectural styles, but none provides a clear
understanding of the similarities among a large number of styles. The basis
of our research is the observation that architectural styles share many
underlying concepts. These shared concepts lead to “architectural
primitives” that can be systematically and constructively composed to
obtain elements of architectural styles. We have identified eight forms and
nine functions as architectural primitives that, in our understanding,
reflect the syntactic and semantic characteristics of a large number of
styles. While proving such a hypothesis is difficult in the general case, we
demonstrate it within the domain of network-based styles. Partial formal
models of style elements composed from these architectural primitives are
also constructed and shown to be analyzable. Document characteristics:
Submitted to ESEC/FSE 2003 added: March 16, 2003 USC-CSE-2003-502 PDF Estimating the Cost of Security for COTS Software Donald J. Reifer, Barry W. Boehm, and Murali
Gangadharan This
paper describes enhancements being made to the Document characteristics: In Proceedings
of 2nd International Conference on COTS-Based Software Systems,
February 2003 added: USC-CSE-2003-501 PDF Not All CBS Are Created Equally: COTS-Intensive
Project Types Barry W. Boehm, COTS
products affect development strategies and tactics, but not all CBS
development efforts are equal. Based on our experiences with 20 large
government and industry CBS projects assessed during our development of the
COCOTS estimation model, and our hands-on experience with 52 small e-services
CBS projects within USC's graduate level software
engineering course, we have identified four distinct CBS activity areas:
assessment intensive, tailoring intensive, glue-code intensive, and non-COTS
intensive. The CBS activity type fundamentally affects the COTS related
activity effort and project risks. In this work we define the three COTS
activity intensive CBS types and discuss their strategic comparisons based on
an empirical study of the spectrum of large and small CBS projects.
added: USC-CSE-2003-500 PDF JavaBeans
and Software Architecture
Nenad Medvidovic, and Nikunj
Mehta
Java has emerged as a popular
programming language and platform for Web applications. JavaBeans? defines the software component model in the Java
programming language that is used for creating reusable, coarse-grained
components. Beans are used in numerous complementary technologies including |
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