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2003
Papers:
(listed in reverse chronological
order for 2003)
ESD-WP-2003-10-Epistemology
in Engineering Systems
by
Prof. Daniel
D. Frey, Massachusetts Institute of
Technology
The
engineering systems division at MIT has
adopted an official vision statement --
“ESD will be a leader in understanding,
modeling, predicting and affecting the structure
and behavior of technologically enabled
complex systems.” To fulfill this
vision, I think it is worthwhile for ESD
faculty to reflect on epistemology and its
relationship to engineering systems. Epistemology
is the branch of philosophy concerned with
the nature of knowledge, justification,
evidence, and related notions. By reflecting
upon epistemology, we may clarify in our
own minds how we come to know something
about engineering systems and thereby improve
our research methods. In this white paper,
I pose five questions related to epistemology
and engineering systems. I also discuss
possible answers, but my goal was primarily
to spark discussion rather than solidify
a position.
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ESD-WP-2003-09-ITS:
What We Know Now that We Wish We Knew Then:
A Retrospective on the ITS 1992 Strategic
Plan
by
Prof. Joseph
M. Sussman, Massachusetts Institute
of Technology
From
September 1991 until June 1992, a core writing
team, which included the author, worked
on what was the first Intelligent Transportation
Systems (ITS) strategic plan in the United
States. This plan was entitled, "A
Strategic Plan for IVHS in the United States."
It served to define the ITS program at a
national scale in a way that has been characterized
as seminal.
The
plan, by most accounts, served as the blueprint
for the early development of ITS in the
U.S. and as the basis for the subsequent
plans produced by ITS America, the federal
government, various states, and a number
of private-sector organizations.
This
paper explores numerous aspects of ITS retrospectively,
contrasting views from 11 years ago, when
the Strategic Plan was produced, with the
current reality. Areas discussed include
Advanced Traveler Information Systems (ATIS),
Advanced Transportation Management Systems
(ATMS), reliability, getting the ITS program
off the ground in the early 90s, strategic
use of information, automated network management,
electronic toll collection (ETC), congestion
pricing, architecture, commercial vehicle
operations (CVO), Advanced Public Transportation
Systems (APTS), and regions.
The
paper closes by comparing ITS with the Interstate,
and finally by discussing the upcoming reauthorization
of the Transportation Efficiency Act for
the 21st Century (TEA-21) and what has been
learned through this retrospective about
ITS-related issues on that reauthorization.
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ESD-WP-2003-08-Lean
Transformation in the U.S. Aerospace Industry:
Appreciating Interdependent Social and Technical
Systems
Lean
practices and principles build on a half-century
of successive initiatives aimed at transforming
social and technical systems in organizations.
While they are seen as central to the revitalization
of the U.S. aerospace industry, there is
great variation in the degree to which lean
initiatives emphasize just technical/manufacturing
systems versus additional social and enterprise
dimensions. Based on a national random sample
survey of 362 U.S. aerospace facilities,
this paper examines factors that account
for the incidence of lean practices and
the impact on outcomes relevant to key stakeholders.
While structural factors such as industry
sector, facility size and others have limited
explanatory power, two process factors—organizational
learning and the value placed on intellectual
capital —do account for the increased
presence of lean practices. In examining
employment outcomes, facilities higher just
on the technical/manufacturing aspects of
lean have a significant and negative impact
on job growth, while facilities higher around
the social systems associated with lean
have significant and positive employment
growth. This finding is consistent with
the views of critics of the more narrow
technical, manufacturing-oriented approaches
to lean as a threat to employment and it
validate proponents of a broader value-creating
approach to lean as a way of growing the
enterprise. Enterprise dimensions of lean
(including both social and technical aspects
of lean) have a positive impact on productivity.
Examining outcomes relevant to multiple
stakeholders and various factor inputs produces
a more complete understanding of the limitations
and potential for lean transformation in
the aerospace industry.
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ESD-WP-2003-07-A
Proposal to Improve the Health Care Systems
for the Urban Poor in the Squatter Settlements
of the Developing Countries
by
Prof. Richard
Larson and Nebibe Varol, Massachusetts
Institute of Technology
Rapid
urbanization and large scale population
movements from rural to urban areas have
resulted in unprecedented health crises
in the developing countries. In addition
to communicable diseases, respiratory infections
and malnutrition, psycho-social stresses
due to marginalization and exclusion from
social activities and employment prospects
are also prevalent. Considering the rate
of urban growth rate and the rapid increase
in the percentage of the poor living in
urban areas, the debilitating effects of
health crises and urban poverty are going
to exacerbate if no precautions are taken.
In this respect, it is a critical point
in time to come up with effective health
care strategies for the urban poor. This
document provides an insight into the reasons
behind the current health problems of the
urban poor and the determinants of health
in developing countries, and proposes use
of operations research to come up with handling
strategies for the major subdivisions of
the health problem in the developing world.
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ESD-WP-2003-06-Role
of Technology in Manufacturing Competitiveness
by
Professor Thomas
Eagar, Thomas Lord Professor of Materials
Engineering and Engineering Systems, Massachusetts
Institute of Technology, Christopher Musso,
Engineering Systems Division, Massachusetts
Institute of Technology
A
manufacturing revolution has emerged in
the past 50 years that is as significant
as the industrial revolution of the 19th
century. From 1950 to 2000, the average
productivity growth in manufacturing in
the United States was 2.8% per year, and
this figure has been accelerating for the
past two decades as manufacturing productivity
growth has exceeded
the average of other sectors by more than
one percent per year (please see table below).
Stated more simply, a US manufacturing worker
can produce four times as much per hour
today as compared with fifty years ago.
This gain has resulted from competitive
pressures, the advent of new technologies,
and a series of product and process innovations.
It has also resulted in a much higher standard
of living for Americans, as products become
more useful and more affordable. In order
to utilize this new manufacturing capacity,
U.S. firms (and others) have expanded their
marketing abroad, creating rapid increase
in global trade.
The
perception of a crisis in American manufacturing
is the result of one of the most difficult
realities of large gains in productivity:
additional capacity almost always exceeds
increased consumption. This results in an
inevitable shift of labor. Industries become
more productive as they mature, and competitive
pressures increase. These two factors require
companies to decrease their workforce and
often result in movement of commodity industries
overseas. The end result is a loss of jobs
in the United States. Displaced workers
must shift to new occupations, requiring
new skills and abilities. History has shown
that this shift can be either detrimental
or beneficial to workers; the most important
determinant of benefit is the presence of
innovative new industries, which, create
high value for their markets. The sustainability
of growth in the U.S. manufacturing sector
is based on the ability of America to continue
to innovate. Innovation is the key to a
vibrant U.S. manufacturing base and continued
generation of new jobs.
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ESD-WP-2003-05-How
Useful is Quantitative Risk Assessment?
by
Professor George
E. Apostolakis, Massachusetts Institute
of Technology
This article discusses the use of Quantitative
Risk Assessment (QRA) in decision-making
regarding the safety of complex technological
systems. The insights gained by QRA are
compared with those from traditional safety
methods and it is argued that the two approaches
complement each other. It is argued that
peer review is an essential part of the
QRA process. The importance of risk-informed
rather than risk-based decision-making is
emphasized. Engineering insights derived
from QRAs are always used in combination
with traditional safety requirements and
it is in this context that they should be
reviewed and critiqued. Examples from applications
in nuclear power, space systems, and an
incinerator of chemical agents are given
to demonstrate the practical benefits of
QRA. Finally, several common criticisms
raised against QRA are addressed.
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ESD-WP-2003-04-Needs
and Possibilities for Engineering Education:
One Industrial/Academic Perspective
by
Christopher
L. Magee, Professor of the Practice
of Mechanical Engineering and Engineering
Systems, Massachusetts Institute of Technology
This paper reports a personal assessment
of the readiness of new B.S. level engineering
graduates to practice engineering immediately
upon graduation. This assessment when reinforced
by significant prior work motivates a systemic
analysis of the U.S. Engineering Education
System. The analysis is framed to address
the implementation potential of ideas for
how educators might efficiently teach undergraduate
engineers “that engineering is more
than differential equations”. The
concepts which seem best from this analysis
are combinations of aggressive intern opportunities
combined with courses (starting in the freshman
year) that emphasize the creative engineering
process. These activities may be containable
in the 4 year program but the analysis also
suggests that extension of engineering education
to 3 or more years beyond the B.S. would
improve the possibility of reaching key
educational goals including teaching adequate
math and science fundamentals as well as
engineering knowledge, process and creativity.
Such radical change will be difficult and
slow to occur (if at all) in this complex
system. Moreover, this system is understandingly
resistant to change because of significant
perceptions of outstanding achievement.
The driving force for change that may be
strong enough to overcome these barriers
is prospective students’ falling perceptions
of engineering education as a preferred
option.
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ESD-WP-2003-03-Metrics
Pilot Project for Military Avionics Sustainment:
Experimental Design and Implementation Plan
by
Kirkor Bozdogan, MIT Co-Lead of the Enterprise
Integration Team (EIT) of the LEAN SUSTAINMENT
INITIATIVE (LSI), Benjamin M. Brandt , Capt.
Brandt (USAF) is a graduate student Research
Assistant and Candidate for the MS Degree
in Technology and Policy at MIT, Joseph
M. Sussman, MIT Co-Lead of the Enterprise
Integration Team (EIT) of the LEAN SUSTAINMENT
INITIATIVE (LSI)
This working paper outlines the design of
an experiment, employing a pilot project,
for identifying and validating new metrics
for managing the US Air Force military avionics
sustainment system. The paper also presents
a plan for implementing the pilot project.
The experimental design allows for the quantitifation
of the effects of the new metrics, while
controlling for the effects of other factors
impacting the observed outcomes.
Underlying
the pilot project, and the proposed experimental
design, are three main hypotheses derived
from earlier research: (a) currently used
metrics foster local optimization rather
than system-wide optimization; (b) they
do not allow measures of progress towards
the achievement of system-wide goals and
objectives, and, hence, do not allow visibility
into the impact of depot maintenance on
the warfighter; and (c) they are driving
the “wrong behavior,” causing
suboptimal decisions governing maintenance
and repair priorities and practices and,
as a result, undermining the efficiency
and effectiveness of the sustainment system,
despite the fact that the Air Force sustainment
system has a dedicated and highly skilled
workforce supporting the warfighter..
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ESD-WP-2003-02-Applying
STAMP in Accident Analysis
by
Nancy
Leveson, Mirna Daouk, Nicolas Dulac,
and Karen Marais, Massachusetts Institute
of Technology
Accident models play a critical role in
accident investigation and analysis. Most
traditional models are based on an underlying
chain of events. These models, however,
have serious limitations when used for complex,
socio-technical systems. Previously, Leveson
proposed a new accident model (STAMP) based
on system theory where the basic concept
is not an event but a constraint. This paper
shows how STAMP can be applied to accident
analysis using three different views or
models of the accident process and proposes
a notation for describing this process.
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ESD-WP-2003-01.01-ESD
Internal Symposium: Incorporating
Uncertainty Into Conceptual Design of Space
System Architectures
The environment in which space systems are
developed and operated can be classified
as nothing less than dynamic. However, it
is clear that the methods and tools relied
on in conceptual design are based on static
assumptions and leave little room for anything
more than snapshots of the product and its
environment. This paper introduces an approach
to challenge that model and instead quantify
and compare space system architectures around
the central theme of uncertainty, with emphasis
on policy uncertainty, as well as, technical
and market uncertainty. Two cases of implementation
are presented and three generalized principles
are proposed that flow from the analysis:
1) engineering systems must be designed
with uncertainty as one of the central organizing
principles, 2) since engineering systems
have management and social dimensions and
thus involve human interactions, there is
an irreducible uncertainty associated with
these dimensions that will affect the design
of the system, and 3) uncertainty in use
may allow the engineering system to satisfy
quite different missions from the original
one intended.
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ESD-WP-2003-01.02-ESD
Internal Symposium: An Attempt
at Complex System Classification
This paper searches for a useful taxonomy
or classification scheme for complex Systems.
There are two aspects to this problem: 1)
distinguishing between Engineering Systems
of interest to ESD (ES) and other Systems,
and 2) differentiating among Engineering
Systems. The first of these has been approached
through general interaction with other ESD
faculty and use of the ESD definitions.
This analysis leads to a proposed specific
set of ES which are human designed, have
high technical and human complexity and
are real, open, dynamic, have hybrid system
states and have both autonomous and human-in–the
loop subsystems or elements.
The
second aspect has been approached by top-down
and bottom-up analysis. A topdown approach
consists of reviewing past system classification
schemes starting with taxonomies proposed
in the context of General Systems Theory
from the 1950’s and assessing their
usefulnesswith the proposed list of ES.
Such schemes prove to be of limited value
in our search because they tended to be
formulated from a mechanical technology
viewpoint and more importantly because they
could not anticipate the emphasis herein
on systems with both technical and human
complexity.
The
proposed or testbed list is also useful
in the bottom-up approach, since it gives
specific cases for qualitative and quantitative
analysis of various system attributes. The
qualitative and preliminary quantitative
study indicates that functional types are
the most useful technical attribute for
classification differentiation. Information,
energy, value and mass acted upon by various
processes are the foundation of the technical
types building on prior work byHubka, Pahl
and Beitz and Van Wyk.
A meta-model for Engineering Systems is
suggested in the form of a multi-layer network
whose goal it is to fulfill human wants
and needs by enabling the flow of goods
and services between sources and sinks.
This description essentially combines and
extends the attributes suggested by the
bottom-up approach to be most useful in
classification.
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ESD-WP-2003-01.03-ESD
Internal Symposium: Physical
Limits to Modularity
Architecture, specifically the definition
of modules and their interconnections, is
a central concern of engineering systems
theory. The freedom to choose modules is
often taken for granted as an essential
design decision. However, physical phenomena
intervene in many cases, with the result
that 1) designers do not have freedom to
choose the modules, or 2) that they will
prefer not to subdivide their system into
as small units as is possible.
A distinction that separates systems with
module freedom from those without seems
to be the absolute level of power needed
to operate the system. VLSI electronics
exemplify the former while mechanical items
like jet engines are examples of the latter.
It has even been argued that the modularity
of VLSI should be extended to mechanical
systems. This paper argues that there are
fundamental reasons, that is, reasons based
on natural phenomena, that keep mechanical
systems from approaching the ideal modularity
of VLSI. The argument is accompanied by
examples.
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ESD-WP-2003-01.04-ESD
Internal Symposium: The Effect
of e-Business on Supply Chain Strategy
Internet technology has forced companies
to redefine their business models so as
to improve the extended enterprise performance
- this is popularly called e-business. The
focus has been on improving the extended
enterprise transactions including Intraorganizational,
Business-to-Consumer (B2C) and Business-to-Business
(B2B) transactions. This shift in corporate
focus allowed a number of companies to employ
a hybrid approach, the Push-Pull supply
chain paradigm. In this article we review
and analyze the evolution of supply chain
strategies from the traditional Push to
Pull and finally to the hybrid Push-Pull
approach. The analysis motivates the development
of a framework that allows companies to
identify the appropriate supply chain strategy
depending on product characteristics. Finally,
we introduce new opportunities that contribute
and support this supply chain paradigm.
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ESD-WP-2003-01.05-ESD
Internal Symposium: Patterns
of Product Development Interactions
Development of complex products and large
systems is a highly interactive social process
involving hundreds of people designing thousands
of interrelated components and making millions
of coupled decisions. Nevertheless, in the
research summarized by this paper, we have
created methods to study the development
process, identify its underlying structures,
and critique its operation. In this article,
we introduce three views of product development
complexity: a process view, a product view,
and an organization view. We are able to
learn about the complex social phenomenon
of product development by studying the patterns
of interaction across the decomposed elements
within each view. We also compare the alignment
of the interaction patterns between the
product, process, and organization domains.
We then propose metrics of product development
complexity by studying and comparing these
interaction patterns. Finally, we develop
hypotheses regarding the patterns of product
development interactions, which will be
helpful to guide future research.
*
This paper also appeared in the proceedings
of the International Conference on Engineering
Design, Glasgow, Scotland, August 2001.
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ESD-WP-2003-01.06-ESD
Internal Symposium: Collected
Views on Complexity in Systems
by
Joseph
M. Sussman, JR East Professor, Professor
of Civil and Environmental Engineering and
Engineering Systems, Massachusetts Institute
of Technology, Cambridge, Massachusetts
The term complexity is used in many different
ways in the systems domain. The different
uses of this term may depend upon the kind
of system being characterized, or perhaps
the disciplinary perspective being brought
to bear.
The
purpose of this paper is to gather and organize
different views of complexity, as espoused
by different authors. The purpose of the
paper is not to make judgments among various
complexity definitions, but rather to draw
together the richness of various intellectual
perspectives about this concept, in order
to understand better how complexity relates
to the concept of engineering systems.
I
have either quoted directly or done my best
to properly paraphrase these ideas, apologizing
for when I have done so incorrectly or in
a misleading fashion. I hope that this paper
will be useful as we begin to think through
the field of engineering systems.
The
paper concludes with some short takes --
pungent observations on complexity by various
scholars -- and some overarching questions
for subsequent discussion.
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ESD-WP-2003-01.07-ESD
Internal Symposium: The Concept
of a CLIOS Analysis Illustrated by the Mexico
City Case
by
Rebecca Dodder, Doctoral Candidate, Technology,
Management & Policy Program and Joseph
M. Sussman, JR East Professor, Professor
of Civil and Environmental Engineering and
Engineering Systems
The term CLIOS (Complex, Large-scale, Integrated,
Open Systems) was conceived as way to capture
the salient characteristics of a class of
systems that are of growing interest to
researchers, decisionmakers, policy makers
and stakeholders. These systems range from
an air traffic control system to the global
climate system, and from Boston’s
Big Dig to the eBay online trading system.
We
start by defining the primary characteristics
of CLIOS. First, a system is complex when
it is composed of a group of interrelated
units (component and subsystems), for which
the degree and nature of the relationships
is imperfectly known – with varying
directionality, magnitude and time-scales
of interactions among the various subsystems.
Second, CLIOS have impacts that are large
in magnitude, and often long-lived and of
large-scale geographical extent. Third,
subsystems within CLIOS are integrated,
closely coupled through feedback loops.
Finally, by open we mean that CLIOS explicitly
include social, political and economic aspects
(Sussman, 2000a).
Finally,
with CLIOS we are as concerned with the
complexity of the organizational and institutional
parts of the systems as we are with the
physical system. In fact, understanding
the organizational and institutional structure
and its interaction with the physical structure
is one of the key potential values of a
CLIOS analysis.
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ESD-WP-2003-01.08-ESD
Internal Symposium: The Evolving
Role of Systems Analysis in Process and
Methods in Large-Scale Public Socio-Technical
Systems
by
David
H. Marks, Goulder Family Professor of
Engineering Systems and Civil and Environmental
Engineering, Director, MIT Laboratory for
Energy and the Environment
The ESD definition of Large-Scale Socio-Technical
Systems is large-scale and complex systems
in which both human and non-human elements
interact where the social and/or management
dimensions tend to dominate. The word public
has been added here to indicate that subset
which are quasi public systems, i.e. the
problems of public management of resources
such as clean air and water or energy in
which public policy is needed to drive and
set the context for public investment and
regulation which in turn influence private
individual and corporate decisions. Systems
analysis plays an important role in the
formation of strategic policy for managing
these resources. The paradigm of systems
analysis as applied to large-scale open
systems has not changed over the years.
It is still the mantra of Problem Identification,
Systems Modeling, Generation of Alternatives
(Optimization), Evaluation and Implementation.
However, both the process by which systems
analysis is carried out, and the systems
methods used in that process have evolved
significantly and for the better. This paper
deals with a description of these evolving
methods and processes in the context of
large-scale energy and environmental systems.
In particular, pathways to the future in
energy and environmental management are
discussed as long-term system analysis problems.
Systems Analysis process changes and methods
changes, which have occurred and will need
evolution in the future, are identified.
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ESD-WP-2003-01.09-ESD
Internal Symposium: Architecting/Designing
Engineering Systems Using Real Options
by
Richard
de Neufville, Professor of Engineering
Systems and of Civil and Environmental Engineering
Everyone
concerned with engineering systems faces
a common issue: How do we design systems
to perform well in a constantly evolving
and thus risky context? As professionals
concerned with the system (rather than its
individual pieces), this design issues predominantly
relates to the overall configuration, the
architecture of the system. This paper presents
an approach to this fundamental issue. It
suggests how we could architect flexible
engineering systems that can evolve optimally
to meet new challenges and opportunities.
It suggests that the methods of “options
analysis”-- that have revolutionized
thinking about investments -- can provide
a conceptual basis for defining optimal
configurations. When these procedures are
applied to design issues, they are generally
known as "real options analysis".
The
fundamental result of "real options
analysis" is the determination of the
value of flexibility. It thus permits system
designers and managers to decide which flexible
design elements, that permit their system
to evolve effectively over time, are worth
their cost. It thus provides a clear rationale
for when to design specific types of flexibility
into the system.
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ESD-WP-2003-01.10-ESD
Internal Symposium: A Control
Engineering Approach to Making Complex Infrastructures
More Efficient and Reliable: A Core Program
for ESD
by
Marija D. Ilic, Professor, Engineering and
Public Policy and Electrical and Computer
Engineering, Carnegie Mellon University
Many of our national infrastructures,
such as electric power, gas pipeline, transportation
and information/communication systems suffer
from common design, planning and operating
problems. As a consequence of these problems,
the infrastructures cannot function at the
same time both efficiently and reliably.
This presents a challenge of national importance
that can be met within our own ESD Program.
In
this paper, I present a research program
using control engineering and systems theory
as a unifying theme for modeling each infrastructure
as a single complex dynamic system encompassing
technical, economic, policy and information
processes. Based on these models, the research
program further seeks to develop controllers
that force the infrastructure to operate
both efficiently and reliably; the controllers
respond to technical, economic and policy
feedback. With these controllers in place,
the design and planning of each infrastructure
will naturally evolve to enhance efficiency
and reliability. Since the controllers respond
to any change in system conditions, they
are equally as effective under malicious
attacks. As such, they can function as a
means of providing secure infrastructures.
The
controllers I envision will operate naturally
under regulated and deregulated policy conditions.
Further, they can themselves evolve as policy
conditions change so as to maintain reliable
and efficient operation of the infrastructure.
Moreover, they can catalyze policy evolution
to support more reliable and efficient operation.
Equally important, they will not just be
traditional controllers that act on feedback
signals to produce actuation signals. They
will also be IT-based decision making tools
that implement flexible information flow-based
protocols between industry participants
so as to support such activities as market
operation and participant learning. Combining
a systematic model-based approach to risk
management with IT-intelligence and distributed
hardware is a real opportunity to provide
a framework for flexible dynamic robustness
in complex systems. Neither IT nor control
engineering by themselves are sufficient
to embark on this tremendous challenge.
One needs a very careful combination of
the data mining techniques and the more
structured control techniques to solve the
problem.
In
what follows, I will explain my vision for
the ESD Program in the context of one infrastructure,
namely the electric power system. This is
the system on which most of my research
has focused. Nonetheless, my vision for
the program can extend to apply to the other
infrastructures named above.
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ESD-WP-2003-01.11-ESD
Internal Symposium: Learning
from Organizational Experience
by
John
S. Carroll, MIT Sloan School of Management,
Jenny W. Rudolph, Boston College Carroll
School of Management, and Sachi Hatakenaka,
MIT Sloan School of Management
Learning-in-action, the cyclical
interplay of thinking and doing, is increasingly
important for organizations as environments
and required capabilities become more complex
and interdependent. Organizational learning
involves both a desire to learn and supportive
structures and mechanisms. We draw upon
three case studies from the nuclear power
and chemical industries to illustrate a
four-stage model of organizational learning:
(1) local stage of decentralized learning
by individuals and work groups, (2) control
stage of fixing problems and complying with
rules, (3) open stage of acknowledgement
of doubt and motivation to learn, and (4)
deep learning stage of skillful inquiry
and systemic mental models. These four stages
differ on whether learning is primarily
single-loop or doubleloop, i.e., whether
the organization can surface and challenge
the assumptions and mental models underlying
behavior, and whether learning is relatively
improvised or structured. The case studies
illustrate how organizations learn differently
from experience, the details of learning
practices, and the nature of stage transitions
among learning practices.
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ESD-WP-2003-01.12-ESD
Internal Symposium: Defining
Engineering Systems: Investigating National
Missile Defense
by
Brian Zuckerman
The MIT Engineering Systems Division is
currently building its intellectual framework.
There is not yet consensus within ESD as
to which tools and methods are central to
the nascent engineering systems approach;
which questions it should address; or the
extent to which qualitative approaches should
be incorporated into it. The goal of this
paper is to sharpen the debate by presenting
multiple analyses of a single engineering
system. Presenting varying perspectives
illuminates issues such as:
- What
types of questions should engineering
systems practitioners ask when analyzing
problems?
- Which
tools are fundamental, which are peripheral,
and which lie outside its purview?
- Is
there a trade-off between the analytical
rigor of different tools and the degree
to which they can address questions the
approach considers important?
- Does
this approach suggest generalizable principles
for analyzing engineering systems?
This paper uses national missile defense
(NMD) as the analytical vehicle for this
approach. By any definition, NMD is an engineering
system. Moreover, the complexity of NMD
facilitates the framing of analyses on multiple
levels, and provides a mechanism for exploring
the ramifications of different potential
definitions of “engineering systems”
as a discipline. Finally, the issue is policy-relevant.
The United States is currently deciding
how to build and deploy NMD; the choice
of system architectures may have important
cost,
foreign policy, military readiness, and
domestic political ramifications. While
there is considerable descriptive information
about system components, there is little
hard data in the open literature regarding
system performance and costs. This paper
draws upon the available literature, while
making estimates where necessary.
It
is important to state at the outset that
this paper assumes two key (and often-disputed)
points. First, it is assumed that technologies
under development will be feasible. Second,
it is assumed that adversaries may build
intercontinental ballistic missiles and
equip them with weapons of mass destruction
(in addition to Russia and China, who already
possess them). The paper therefore should
be read as a vehicle for exploring issues
at the heart of engineering systems rather
than as a policy analysis
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ESD-WP-2003-01.13-ESD
Internal Symposium: System Dynamics:
Systems Thinking and Modeling for a Complex
World
by
John
D. Sterman, MIT Sloan School of Management
Todays problems often arise as unintended
consequences of yesterdays solutions. Social
systems often suffer from policy resistance,
the tendency for well-intentioned interventions
to be defeated by the response of the system
to the intervention itself. The field of
system dynamics, created at MIT in the 1950s
by Jay Forrester, is designed to help us
learn about the structure and dynamics of
the complex systems in which we are embedded,
design high-leverage policies for sustained
improvement, and catalyze successful implementation
and change. Drawing on engineering control
theory and the modern theory of nonlinear
dynamical systems, system dynamics often
involves the development of formal models
and management flight simulators to capture
complex dynamics, and to create an environment
for learning and policy design. Unlike pure
engineering problems if any exist, human
systems present unique challenges, including
long time horizons, issues that cross disciplinary
boundaries, the need to develop reliable
models of human behavior, and the great
difficulty of experimental testing. Successful
change in social systems also requires the
active participation of a wide range of
people in the modeling and policy design
process, people who often lack technical
training. In this paper I discuss requirements
for the effective use of system dynamics
and illustrate with a successful application
to a difficult business issue.
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ESD-WP-2003-01.14-ESD
Internal Symposium: Lean Enterprises
– A Systems Perspective
Becoming a “Lean Enterprise”
is increasingly being recognized as an important
strategy in achieving critical strategic
goals such as responsiveness, cycle time
and cost across all phases of the product
life cycle. The concept of a lean enterprise
is not new. Many books address lean enterprise
topics.1 For example, The Machine That Changed
the World2, the book that introduced lean
terminology, has a chapter on “Managing
Lean Enterprises”. Despite having
much written on this subject, lean enterprises
are only starting to emerge in practice.
Why has it taken so long to transform organizations
to lean enterprises? Lean enterprises are
complex, highly integrated systems comprised
of processes, products, organizations, and
information, with multifaceted interdependencies
and interrelationships across their boundaries.
Understanding, engineering, and managing
these complex social, technical, and infrastructure
processes are critical to becoming
a lean enterprise.
What
then are the attributes of a lean enterprise?
Are there key fundamental principles employed
to achieve a lean enterprise? What are the
key concepts, architecture and interrelationships
that comprise the enterprise “system”?
What is involved in “engineering”
a lean enterprise? This paper will address
these questions along with the critical
issues involved in modeling, analyzing and
understanding the intricacies of complex
enterprise systems.
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ESD-WP-2003-01.15-ESD
Internal Symposium: Nano-technology:
a Disruptive Technology?
The
term "disruptive technology" as
coined by Christensen (1997) refers to a
new technology having lower cost and performance
measured by traditional criteria, but having
higher ancillary performance. Christensen
finds that disruptive technologies may enter
and expand emerging market niches, improving
with time and ultimately attacking established
products in their traditional markets. This
conception, while useful, is also limiting
in several important ways.
By
emphasizing only "attack from below"
Christensen ignores other discontinuous
patterns of change which may be of equal
or greater importance (Utterback, 1994;
Acee, 2001). Further, the true importance
of disruptive technology, even in Christensen's
conception of it is not that it may displace
established products. Rather, it is a powerful
means for enlarging and broadening markets
and providing new functionality.
In
this paper nano-technologies will be considered
in their roles as both disruptive and more
broadly discontinuous or radical innovation.
Various impacts will be assessed with emphasis
on enlarged and new markets that may be
created
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ESD-WP-2003-01.16-ESD
Internal Symposium: Complex
systems: a review
by
Seth Lloyd, MIT Engineering Systems Division,
MIT Department of Mechanical Engineering,
Santa Fe Institute, New England Complex
Systems Institute
Engineers
have worked on complex systems ever since
engineering began. But the sciences of complexity
have come in to their own in the last few
decades. Hoping to find common threads that
weave their disciplines together, researchers
from the fields of physics, biology, chemistry,
math, computer science, economics, anthropology,
linguistics, et al. have banded together
to try to develop unifying frameworks for
understanding complex systems. This paper
reports on successes and failures of these
efforts..
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ESD-WP-2003-01.17-ESD
Internal Symposium: Bits and
Bucks:
Modeling complex systems by information
flow
by
Seth Llyod, MIT and Thomas Lloyd, McKinsey
Los Angeles
This
paper presents a general method for modeling
and characterizing complex systems in terms
of flows of information together with flows
of conserved or quasi-conserved quantities
such as energy or money. Using mathematical
techniques borrowed from statistical mechanics
and from physics of computation, a framework
is constructed that allows general systems
to be modeled in terms of how information,
energy, money, etc. flow between subsystems.
Physical, chemical, biological, engineering,
and commercial systems can all be analyzed
within this framework.
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ESD-WP-2003-01.18-ESD
Internal Symposium: The Link
between Cognition and the Complexity of
Engineering Systems Design
by
John
R. Williams, Associate Professor, Engineering
Systems Division and Civil and Environmental
Engineering Department, Massachusetts Institute
of Technology,
This
paper focuses on the role of human cognition
in the design of large complex systems.
It contrasts the physical system that is
the product of the design with the cognitive
model that is used by the designer to “understand”
the system. The complexity of the system
relevant to the designer is a function not
only of the physical system, but also of
the cognitive model that the designer holds
in his mind. Furthermore, the level of cognitive
model available to an experienced designer
depends on the state of domain knowledge.
To be useful in answering the question,
“How complex is this system to design?”
the state of the domain knowledge available
to the designer must be assessed with respect
to the level at which the design problem
is posed. The concept of conceptual distance
is introduced that depends on the disparity
between the present level of integrated
knowledge and the conceptual level of the
design problem. This “distance”
is a measure of the complexity of the design
task and is called the cognitive complexity
of the design. To investigate the concept
of cognitive complexity a model of human
knowledge is proposed along with a set of
graphical abstractions. It is concluded
that the cognitive complexity of the design
task is neither wholly intrinsic (a property
of the system) nor wholly subjective (a
property of the mind) but requires an objective
evaluation of the engineering problem with
respect to present knowledge. It is noted
that the structure of knowledge in a specific
domain can be mapped and therefore a research
program can be launched to systematically
determine the difficulty of various engineering
endeavors.
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