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- In the burgeoning literature on engineering
systems and related fields, we can all use some navigational aids.
To that end, the ESD Working Paper series introduces a new feature
"Short Takes on the Literature" in which brief informal
commentaries by MIT people on books, reports and papers in our
field are made available to the community. We hope you find these
of value and will also see fit to contribute your own opinions
on the literature as well.
(in reverse chronological order)
 ESD-WP-2009-06
Measuring and Understanding Hierarchy as an Architectural Element
in Industry Sectors
Jianxi Luo
Massachusetts Institute of Technology
Daniel E. Whitney
Massachusetts Institute of Technology
Carliss Y. Baldwin
Harvard Business School
Christopher L. Magee
Massachusetts Institute of Technology
Hierarchy is a generic structure
in which levels are asymmetrically ordered. In an industry setting,
classic supply chains display strict hierarchy, whereas clusters
of firms have linkages going in many different directions. Previous
theory has often assumed the existence of the hierarchical relationships
among firms and empirical work has focused on a single level of
an industry or bilateral relationships. However, quantitative
evidence on the deep hierarchy in large industrial sectors is
lacking. In this paper, we develop metrics and methods to define
and measure the degree of hierarchy in transactional relationships
among firms, and apply the methods to two large industrial sectors
in Japan: automotive and electronics. We compiled the networks
of firms connected by transactional relationships. Our empirical
analysis shows that the automotive sector exhibits a higher degree
of hierarchy than the electronics sector. We further analyze the
differences in hierarchy using a simulation model based on transaction
breadth and transaction specificity. The empirical measurement
and model analysis together indicate that it is the low transaction
specificity that drives down the degree of hierarchy in the electronics
sector. Differences in transaction patterns in turn may result
from the differences in the power level of underlying technologies,
which affect product specificity and asset specificity. Thus,
the degree of hierarchy in an industry sector may be traced back
to fundamental properties of the underlying technologies.
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ESD-WP-2009-05
Framework for the Analysis of the Adaptability, Extensibility,
and Scalability of Semantic Information Integration and the Context
Mediation Approach
by
Thomas Gannon
MITRE Corporation
Stuart
Madnick
Sloan School of Management, MIT
Allen
Moulton
Sloan School of Management, MIT
Michael
Siegel
Sloan School of Management, MIT
Marwan
Sabbouh
MITRE Corporation
Hongwei
Zhu
Old Dominion University
Technological
advances such as Service Oriented Architecture (SOA) have increased
the feasibility and importance of effectively integrating information
from an ever widening number of systems within and across enterprises.
A key difficulty of achieving this goal comes from the pervasive
heterogeneity in all levels of information systems. A robust solution
to this problem needs to be adaptable, extensible, and scalable.
In this paper, we identify the deficiencies of traditional semantic
integration approaches. The COntext INterchange (COIN) approach
overcomes these deficiencies by declaratively representing data
semantics and using a mediator to create the necessary conversion
programs from a small number of conversion rules. The capabilities
of COIN is demonstrated using an example with 150 data sources,
where COIN can automatically generate the over 22,000 conversion
programs needed to enable semantic interoperability using only
six parametizable conversion rules. This paper presents a framework
for evaluating adaptability, extensibility, and scalability of
semantic integration approaches. The application of the framework
is demonstrated with a systematic evaluation of COIN and other
commonly practiced approaches..
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ESD-WP-2009-04
Technology Forecasting Using Data Mining and Semantics: First
Annual Report
by
Wei Lee Woon
Masdar Institute of Science and Technology, Abu Dhabi,
United Arab Emirates
Stuart
Madnick
Sloan School of Management, MIT
Ayse
Firat
Doctoral Candidate, Engineering Systems, MIT
Blaine
Ziegler
Doctoral Candidate, Electrical Eng. & Computer Sci.,
MIT
Satwik
Seshasai
Doctoral Candidate, Engineering Systems, MIT
The
planning and management of research and development is a challenging
process which is compounded by the large amounts of information
which is available. The goal of this project is to mine science
and technology databases for patterns and trends which facilitate
the formation of research strategies. Examples of the types of
information sources which we exploit are diverse and include academic
journals, patents, blogs and news stories. The intended outputs
of the project include growth forecasts for various technological
sectors (with an emphasis on sustainable energy), an improved
understanding of the underlying research landscape, as well as
the identification of influential researchers or research groups.
This
paper focuses on the development of techniques to both organize
and visualize the data in a way which reflects the semantic relationships
between keywords. We studied the use of the joint term frequencies
of pairs of keywords, as a means of characterizing this semantic
relationship – this is based on the intuition that terms
which frequently appear together are more likely to be closely
related. Some of the results reported herein describe: (1) Using
appropriate tools and methods, exploitable patterns and information
can certainly be extracted from publicly available databases,
(2) Adaptation of the Normalized Google Distance (NGD) formalism
can provide measures of keyword distances that facilitate keyword
clustering and hierarchical visualization, (3) Further adaptation
of the NGD formalism can be used to provide an asymmetric measure
of keyword distances to allow the automatic creation of a keyword
taxonomy, and (4) Adaptation of the Latent Semantic Approach (LSA)
can be used to identify concepts underlying collections of keywords..
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ESD-WP-2009-03
Reconciliation of temporal semantic heterogeneity in evolving
information systems
by
Hongwei Zhu
College Business and Public Administration, Old Dominion
University
Stuart
Madnick
Sloan School of Management, MIT
The
change in meaning of data over time poses significant challenges
for the use of that data. These challenges exist in the use of
an individual data source and are further compounded with the
integration of multiple sources. In this paper, we identify three
types of temporal semantic heterogeneity. We propose a solution
based on extensions to the Context Interchange framework, which
has mechanisms for capturing semantics using ontology and temporal
context. It also provides a mediation service that automatically
reconciles semantic conflicts. We show the feasibility of this
approach with a prototype that implements a subset of the proposed
extensions.
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ESD-WP-2009-02
Preventing Accidents and Building a Culture of Safety: Insights
from a Simulation Model
by
John Lyneis
Sloan School of Management, MIT
Stuart
Madnick
Sloan School of Management, MIT
Research
has approached the topic of safety in organizations from a number
of different perspectives. On the one hand, psychological research
on safety climate gives evidence for a range of organizational
factors that predict safety across organizations. On the other
hand, organizational learning theorists view safety as a dynamic
problem in which organizations must learn from mistakes. Here,
we synthesize these two streams of research by incorporating key
organizational factors from the safety climate literature into
a dynamic simulation model that also includes the possibility
for learning. Analysis of simulation results sheds insight into
the nature of reliability and confirms the dangers of over-reliance
on ‘single loop learning’ as a mechanism for controlling
safety behaviors. Special emphasis is placed on strategies that
managers might use to encourage learning and prevent erosion in
safety behaviors over time.
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ESD-WP-2009-01
Does Geographic Clustering Still Benefit High Tech New Ventures?
The Case of the Cambridge/Boston Biotech Cluster
by
Thomas J. Allen
MIT Engineering Systems Division
Ornit
Raz
Research Affiliate, MIT Engineering Systems Division
Peter
Gloor
Research Scientist, MIT Center for Collective Intelligence
An
empirical study of scientific communication among biotechnology
companies supports the belief that geographic clustering does
produce increased scientific exchange among companies. A comparison
of companies within a constrained geographic area with those more
dispersed shows a significantly higher level of scientific communication
among the former. Scientific communication declines rapidly with
plupical separation.
Critical
of the formation of cluster – based scientific communication
networks is the presence of both universities and large firms
from the same industry.
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