| |
2005
Papers:
(listed in reverse chronological
order for 2005)
ESD-WP-2005-10-Degree
Correlations and Motifs in Technological
Networks
Recent
network research has sought to characterize
complex systems with a number of statistical
metrics, such as power law exponent (if
any), clustering coefficient, community
behavior, and degree correlation. A larger
goal of such research is to obtain insight
into the systems’ functions by means
of these and similar analyses. In this paper
we examine network models of mechanical
assemblies. Such systems are well understood
functionally. We show that they have both
rich and varied community structure as well
as negative degree correlations (disassortative
mixing), and show that this can be explained
by additional powerful constraints that
arise from identifiable first principles.
In addition, we note that their main “motif”
is closed loops (as it is for electric and
electronic circuits), a pattern that conventional
network analysis does not detect but which
is used by software designed to aid in the
design of such systems. The implication
is that functional understanding of complex
systems requires considerable domain knowledge
beyond what typical network analysis tools
employ.
>
top
ESD-WP-2005-09-Analysis
of the Malaysian Toll Road Public-Private
Partnership Program and Recommendations
for Policy Improvements
Malaysia
has relied on toll road public-private partnerships
(PPPs) for over twenty years to provide
important highway infrastructure. The program
has been active with nearly 1800 kilometers
either constructed or concessions agreed
to. The public has been less supportive
of the program due to low transparency and
little public involvement. Public protests
are common, which may lead to long-term
program instability. The CLIOS Process,
developed at MIT, is applied to Malaysia’s
toll road PPP program to develop new policies
that can better meet these public concerns
while maintaining the financial viability
of the sector. With increases in transparency
and public involvement, the political risks
of the program should be reduced and long-term
stability for the government and concessionaires
improved. We argue that the focus should
be at the regional transportation planning
level where toll road PPPs can be compared
with alternatives for meeting transportation
needs rather than at the national level
where Malaysian toll road PPPs are currently
handled.
>
top
ESD-WP-2005-08-Using
Design Structure Matrices to Improve Decentralized
Urban Transportation Systems
Management
of large, complex, urban transportation
systems involves numerous stakeholders due
to the decentralized ownership and operation
of distinct pieces of the physical network
and services. In order to deliver better
service to users, many urban regions are
adopting technological and operational solutions,
both of which necessitate interaction among
the decentralized organizations. This research
applies systems engineering analysis techniques—the
design structure matrix (DSM) and clustering—in
order to improve the efficiency and effectiveness
of organizational interactions between agencies
as they deploy Intelligent Transportation
Systems (ITS) and attempt to integrate their
operations. Specifically, we examine the
application of clustering to the institutional
structure set forth by the Regional ITS
Architecture for metropolitan Seattle.
>
top
ESD-WP-2005-07-Characterizing
Three Engineering Systems Methods for Supporting
Regional Strategic Transportation Planning
Applied to Freight Systems
by
Sgouris P. Sgouridis, Joseph
M. Sussman, and Christopher Glazner
A
systems perspective for regional strategic
transportation planning (RSTP) for freight
movements involves an understanding of Supply
Chain Management (SCM). This paper starts
from the premise that the public sector
needs to enhance economic development in
the form of providing and ensuring the operation
of sufficient network capacity for freight
needs but at the same time secure the region’s
long term environmental and societal well
being. The need for long-term integrated
transportation planning that is sensitive
to supply chain needs and environmental
nuances can be supported by the use of engineering
systems methodologies. Here we demonstrate
the use and potential of three such methods:
Design Structure Matrix (DSM), System Architecture
(SA) and System Dynamics in support of a
transportation planning process that integrates
SCM considerations into RSTP.
>
top
ESD-WP-2005-06-Multi-Airport
Systems in the Era of No-Frills Airlines
The
development of no-frills airlines is promoting
a remarkable expansion in the number of
secondary airports in major metropolitan
areas. These new carriers are creating a
significant alternative to the traditional
full-service carriers. In effect, they are
establishing a parallel market and corresponding
network of airports. This conclusion results
from the analysis of a worldwide database
on major metropolitan airports.
This
effect supplements the "number of originating
passengers", that has been the traditional
significant factor that promotes the establishment
of viable multi-airport systems. This factor
maintains its importance, but no longer
is as decisive as it has been.
Airlines
and airport policies further reinforce the
independent network of secondary airports.
Nofrills airlines that sell only through
the web to customers effectively cause their
services at secondary airports to disappear
from the airline reservation systems. Airports
that choose not to provide low-cost service
to no-frills airlines likewise strengthen
the role of the secondary airports. Such
strategies, most visible in Europe, have
led to a remarkable proliferation of secondary
airports in unexpected areas.
This
trend implies a traffic shift away from
the expensive, congested airports toward
the no-frills, inexpensive and uncongested
airports in major metropolitan areas. If
the current major airlines do shrink substantially,
as could happen, this would greatly change
the pattern of airport traffic in major
metropolitan areas.
>
top
ESD-WP-2005-05-Building
Real Options into Physical Systems with
Stochastic Mixed-Integer Programming
The
problem of building real options into physical
systems has three features:
-
real options are not as easily defined
as financial options;
-
path-dependency and interdependencies
among projects mean that the standard
tools of options analysis tools are insufficient;
and
-
the focus is on identifying the best way
to build flexibility into the design –
not to
value individual options.
This
paper suggests a framework for exploring
real options in physical systems that especially
addresses these two difficulties. This framework
has two stages: options identification and
options analysis. The options identification
stage consists of screening and simulation
models that focus attention on a small subset
of the possible combination of projects.
The options analysis stage uses stochastic
mixed-integer programming to manage the
path-dependency and interdependency features.
This stochastic formulation enables the
analyst to include more technical details
and develop explicit plans for the execution
of projects according to the contingencies
that arise. The paper illustrates the approach
with a case study of a water resources planning
problem, but the framework is generally
applicable to a variety of large-scale physical
systems.
>
top
ESD-WP-2005-04-Management
of Technology Investment Risk with Real
Options-Based Design: A case study of an
innovative building technology
Implementation
of innovative technologies is hindered by
the perceived risks of technical failure
or increased first cost. However, by designing
a system to include real options within
its architecture and by recognizing the
value in operational flexibility, the project’s
value is structured to avoid downside risks
yet benefit from upside opportunities. A
real options based methodology for innovative
engineering system design consists of identifying
relevant uncertainties, designing options
“in” the system, and modeling
the performance of the options-based design
subject to the uncertainties. The results
guide decision makers on how much to spend
on the design and construction of a flexible
system. A case study of the market value
of an innovative naturally ventilated building
with embedded option to install mechanical
cooling in the future demonstrates how the
option “in” the system protects
the asset from downside outcomes in market
value yet allows it to benefit from upside
opportunities.
>
top
ESD-WP-2005-03-Value-at-RiskAnalysis
for Real Options in Complex Engineered Systems
This
paper presents a simple but powerful Real
Options Valuation methodology suitable for
valuing flexibility in complex engineered
systems. It is based on value-at-risk analysis
and relies on a standard discounted cash
flow approach. A case study on the architecting
of flexible satellite fleets is presented.
The architecting framework integrates spacecraft
engineering design with economic analysis
for the purpose of maximizing the financial
value of a fleet to the operator under uncertain,
evolving market conditions. The investigation
considers the forecasted demand evolution
for a satellite service in two distant geographical
markets simultaneously and provides flexible
fleet architectures that significantly improve
various aspects of the value-at-risk distributions
compared to those of a traditional, rigid
fleet architecture. It is shown that the
flexible architectures are able to capture
more revenue, mitigate more risk and/or
reduce overall required investment. The
suggested Real Options “in”
the system, rather than “on”
the system, approach allows engineers, strategists,
or decision makers in engineering establishments
to embed flexibility in the design of complex
systems for the purpose of maximizing their
total lifetime value.
>
top
ESD-WP-2005-02-Semantic
Information Integration in the Large: Adaptability,
Extensibility, and Scalability of the Context
Mediation Approach
by
Thomas Gannon, Stuart
Madnick, Allen Moulton, Michael Siegel,
Marwan Sabbouh, Hongwei Zhu
There
is pressing need for effectively integrating
information from an ever increasing number
of available sources both on the web and
in other existing systems. A key difficulty
of achieving this goal comes from the pervasive
heterogeneities in all levels of information
systems. Existing and emerging technologies,
such as the Web, ODBC, XML, and Web Services,
provide essential capabilities in resolving
heterogeneities in the hardware and software
platforms, but they do not address the semantic
heterogeneity of the data itself. A robust
solution to this problem needs to be adaptable,
extensible, and scalable.
In
this paper, we identify the deficiencies
of traditional approaches that address this
problem using hand-coded programs or require
complete data standardization. The COntext
INterchange (COIN) approach overcomes these
deficiencies by declaratively representing
data semantics and using a mediator to create
the necessary conversion programs using
a small number of conversion rules. The
capabilities of COIN is demonstrated using
an intelligence information integration
example consisting of 150 data sources,
where COIN can automatically generate the
over 22,000 conversion programs needed to
enable semantic integration using only six
parametizable conversion rules. This paper
makes a unique contribution by providing
a systematic evaluation of COIN and other
commonly practiced approaches.
>
top
ESD-WP-2005-01-Research
Initiative to Understand & Model State
Stability: Exploiting System Dynamics
by
Nazli Choucri, Stuart
E. Madnick, Michael D. Siegel
In
its Preface, The 9/11 Commission Report
states: “We learned that the institutions
charted with protecting …national
security did not understand how grave this
threat can be, and did not adjust their
policies, plans, and practices to deter
or defeat it” (2004: xvi). Given current
realities and uncertainties “better
preparedness” can be achieved by identifying,
controlling and managing the elusive linkages
and situational factors that impact state
stability and fuel state decay and destruction
– and hence create new threats to
the nation’s security.
We
propose to focus on the use of system dynamics
modeling techniques to help understand,
measure and model the complex dynamics shaping
state stability, initially for two regions.
We will specifically consider the impacts
of unanticipated disruptions, such as a
tsunami and its aftermath, on the dynamics
of the two regions. For each region, we
will deliver a detailed country model, including
3-5 futures predictions in the 6-12 month
range along with an analysis of conditions
and casual links between predicted futures
plus corresponding mitigated options.
>
top
|
|
