\chapter{Introduction}
\section{Purpose}

Arcology design combines urban planning and architecture with the
mechanics of ecology, essentially forming a dense but ideally
independently sustainable human habitation system.
The complexity posed by these systems is
well-suited for systems engineering analysis.

From a historical perspective, arcologies are mostly the subject of
science fiction.  In a typical scenario, the principles of arcology
development are applied to the design of self-contained habitats, where
the major challenge lies in finding ways for large groups of people to
tolerate living in close proximity to one another.  In addition to
maximizing quality of life for its residents, the arcology needs to
limit consumption of land, energy, time, and human resources.  Achieving
an appropriate balance in these (often competing) criteria requires that
designers look beyond maximization of personal productivity and/or
economic performance, and explicitly consider relationships among all
factors affecting system functionality, performance, and resource
consumption.  The common characteristics of ``good design solutions'' include: 

\begin{enumerate}
 \item[(1)] Retrofit of present-day urban sprawls with large
      three-dimensional integrated urban forms (\emph{i.e.}, municipal
      hyperstructures),
 \item[(2)] Extensive use of multi-functional spaces, and
 \item[(3)] Use of sophisticated transportation networks and systems to
      transfer of people and resources (\emph{e.g.}, power and water)
      between spaces.
\end{enumerate}

\vspace{0.0 truein}\noindent
Present-day trends in population growth and urbanization suggest that
as time marches forward, spearheading ideas associated with
arcology development will only beome more important.
To put this observation on a quantitative footing,
we first note that as of July 2006, the World's population
is 6.5 billion (and growing annually at 1.14\%).
Since 1900 there has been a significant movement of
the World's population to urban areas,
growing from 14\% in 1900 to approximately 50\% in 2000.
The United Nations reports that by 2030,
not only will 60\% of the worlds population be
urban, but nearly all of the anticipated
growth will be urban growth\cite{united-nations2002}.

Rural-to-urban area migration is driven by a number of factors including:
(1) the declining importance of agriculturally-based economies,
(2) improved opportunity for access to services, and
(3) improved opportunities that urban areas provide for
specialization (when people congregate in urban areas they can
specialize to a much greater extent than in rural areas\cite{vargha1995}).
Rural-to-urban area migration is enabled by access to housing
and the ability of communication and transportation networks
to form in response to supply and demand mechanisms.
The latter is especially important because in order for the
operation of high-population urban areas to be sustainable,
efficient modes of transportation are needed to
transport goods and people throughout the arcology.

From the earliest days of transportation infrastructure development,
new transportation networks -- initially railway, then road -- were
ultimately built to increase the value of the
land surrounding the network\cite{emmi2003}.
Road and rail access stimulates urban growth, which in turn
drives the need for more network development.
Clearly, this cycle cannot continue forever.
It is reasonable to expect that since land is a limited resource, 
its value will only increase at faster and faster
rates as the worlds population increases.
Since fewer and fewer people will have the economic means
to migrate to sprawling (low-density) urban areas,
high-density urban area will become more common.
Thus, it may only be a matter of decades until
modeling techniques tailored toward the needs of arcologies
and/or other forms of well-integrated compact cities become common place.
Early indicators of this outcome can be found in
experimental prototypes for sustainable living (e.g., BioSphere 2
\cite{biosphere2}) and long-term plans for dense sustainable communities
and major city structures in East Asia
\cite{takenaka,millenniumtower,frick,tsui,ecodesigns}.

\subsection*{Project Objectives}  

This thesis defines and describes a simulation framework for the
execution of optimized demand-responsive multimodal mass transit
schemes, such as those found in complex urban environments.  Attention
is focused on resident and employer needs (i.e., shuttling passengers
from their source stations to their destination stations.)  By measuring
the performance of various solutions, we aim to determine effective
strategies for efficiently transferring people to their destinations in
relation to input parameters such as demand, transit network topology,
and the relative size(s) of the vehicles used in the fleet.  This
framework also allows us to experiment with different urban planning
layouts and to investigate relationships between services provided by
data networks and transportation networks.  For example, if a city
decides to spend money upgrading their data infrastructure so more
people might be able to telecommute to work, then this may have a
critical impact on the load on their mass transit system.

While the simulation and optimization models are certainly generic
enough to apply to most ordinary forms of mass transit, for two reasons
this project chooses to frame models in the in the context of an arcology.
First, the word ``arcology'' still remains rather
unique in the global namespace of the engineering field, and connotes a
flair for futurism.  More importantly, the design focus of arcologies as
an autonomous structure encourages us to analyze it in terms of control
volumes, defining the flows of input and output products in ways much
more conducive to identifying resource consumption and environmental
impact. While the concept of analysis via the definition of control
volumes may come naturally to engineers trained in thermodynamics, it is
refreshing to see efforts emerging to track our ``carbon footprint'' as
part of a global carbon dioxide emissions budget. Hopefully this step
will preclude more complete tracking and accounting (and eventually
optimization) of human environmental resource use and waste reclamation.

\section{Inspiration for Arcology Modeling}

It all goes back to the meaning of life, doesn't it?  Humans spend
inordinate amounts of time looking for love or money or happiness,
always trying to get the most out of life - in essence optimizing our
existence in some fashion.  The optimization part is where simulation
can be a useful tool, as we often disagree on what infrastructure
improvements we could make in order to make us happier or richer or work
not so far from our loved ones. For all the aspirations we've had over
the decades of reaching for the stars and developing permanent space
colonies, I'm surprised by the relatively little success we've had in
improving the efficiency of our lifestyles in our dwellings right here
on Earth.  As summarized in Table \ref{tab:municipal-home-interfaces},
the ideal American domicile still typically consists of the single
family home, an almost completely isolated pocket of land connected to
the rest of the community only by a few wires, pipes, and a stretch of
pavement.  What goes across these interfaces? And how might they be
improved and rearranged by municipal facilities to make the city as a
whole more sustainable, flexible, and efficient?

\begin{table}[t]
\begin{tabular}{|r|l|l|}
\hline 
\textbf{\scriptsize Category}&
\textbf{\scriptsize Current Interfaces}&
\textbf{\scriptsize Potential Future Interfaces}\tabularnewline
\hline
\hline 
\textbf{\scriptsize Physical}&
\multicolumn{1}{p{0.3\columnwidth}|}{{\scriptsize Driveway, Parking, Mailbox}}&
\multicolumn{1}{p{0.3\columnwidth}|}{{\scriptsize Driveway, Automated Package Transport}}\tabularnewline
\hline 
\textbf{\scriptsize Utilities}&
\multicolumn{1}{p{0.3\columnwidth}|}{{\scriptsize Electricity, Gas, Water, Sewage}}&
\multicolumn{1}{p{0.3\columnwidth}|}{{\scriptsize Electricity, HVAC, Fuel (Gas, Hydrogen), Water, Sewage}}\tabularnewline
\hline 
\textbf{\scriptsize Wired Communication}&
\multicolumn{1}{p{0.3\columnwidth}|}{{\scriptsize Copper / Fiber medium for Telephone, Cable TV, Internet}}&
\multicolumn{1}{p{0.3\textwidth}|}{{\scriptsize Junction Box, redundant trunks}}\tabularnewline
\hline 
\textbf{\scriptsize Wireless Communication}&
\multicolumn{1}{p{0.3\columnwidth}|}{{\scriptsize Broadcast Radio/TV, Cell phone, Satellite, WiFi}}&
\multicolumn{1}{p{0.3\columnwidth}|}{{\scriptsize distribution points to common aerials, satellite dishes}}\tabularnewline
\hline
\end{tabular}
\caption{Municipal home interfaces}
\label{tab:municipal-home-interfaces}
\end{table}


As a first step toward understanding these complexities, let us note
that living systems seem to have a natural tendency to miniaturize
complexity, both in space and time.  A mathematician might draw the
analogy that we live on the interesting boundary region of a fractal,
often surrounded by vast regions of fairly uniform space. While the sun
and stars and universe are beautiful and magnificent only when observed
on a grand scale, I'd surmise that they are not as interesting when
studied on the same scale as, say, the inner workings of a
paramecium. That's one of the main reasons as astronomers, we might
search the heavens for deeper understanding of celestial mechanics, but
hope to discover other forms of complex alien life. For we could only
have hope to interact with other living systems of sufficient complexity
that exist on a similar space and time scale as we do. Meanwhile, the
progression of life on Earth as a whole apparently strives to fit more
and more complexity into the spaces it is able to fill.

If we drew a control volume around an ecosystem, we'd find that it
functions as an engine that harnesses existing energy gradients in order
to further decrease the entropy of its local area. Through continuing
that progress, we've begun to expand the boundaries between which
objects of vastly different scales can interact. Lately we've been
peering into the inner workings of relatively tiny, fast computing
devices, which will soon be governed increasingly by subatomic
interactions between quantum particles, which in turn affect what we do
with our lives and our global economy. That's amazing. Someday soon, we
also expect that the tiny electrical processes that occur in our
microchips may go on to help us alter the courses of celestial bodies,
perhaps to allow us to produce some kind of pronounced impact (or avoid
an impact) in the cosmic ballet of planets. But for now, one of our
primary (although not yet fully utilized) uses for our microprocessing
technology often is the guidance of the course of our vehicles and
information delivery systems.

\subsection*{Influential Literature}
The specific concept of the arcology was first introduced in the 1950s
by architect Paolo Soleri as the ultimate urban planning solution to the
inherent problems of metropolitan growth\cite{soleri}. Continuing trends
in the expansion of metropolitan areas have contributed to explosive
growth of low density suburban sprawl, the decay of inner city urban
areas, and finally the indiscriminate destruction of natural
environments to make room for a human habitat system which is
increasingly less efficient, less convenient, less and
aesthetically pleasing. The concept of the arcology attempts to reverse
those trends by providing a compact city infrastructure that works well
and manages to reprocess most of its waste before returning material
back to the environment for further reclamation.

What exactly \emph{is} an arcology by definition? Featured in several
science fiction works as futuristic cities, an arcology is more than
simply just a colossal structure or superbuilding.  The arcology
integrates living spaces and working spaces with transportation systems
that connect it all together.  One of the fundamental differences
between arcologies and conventional cities is the emphasis on the
effective use of the vertical dimension in city planning. An arcology
design would strive to make use of several independent but functionally
intertwined layers or horizontal planes, whereas current urban planning
focuses more on flat zoning of commercial / residential / industrial
areas through processes that result in a more ad hoc placement based on
the situational needs and political landscape at the time.  Another
distinguishing characteristic is the arcology's roots in urban
agriculture, meaning deliberate collection and reprocessing of waste
byproducts. The arcology might simply be described as what a city would
look like if it was designed from the start by competent systems
engineers, incorporating modular growth packages, standardized by
upgradable interconnects, and fault tolerant, serviceable components.
Of course, this feat is easier said than done, but the basic
architectural core building blocks and modular techniques have been
around. Meanwhile, the fact that the construction of many large city
buildings has gradually been consolidated into one or two large
developers means that a single party can finally expect to see gains
through the extra effort of standardization.

In 1978 George Dantzig and Thomas Saaty (fathers of Linear Programming
and the Analytic Hierarchy Process, respectively) got together to write
\emph{Compact City} \cite{compactcity}, providing a compelling vision on
how this human habitat could work from a technical standpoint.  This
fascinating book contemplates the feasibility of constructing a livable
city of between $\frac{1}{4}$ million to 2 million residents within a
2-4 square mile, 4-8 level cylindrical superstructure.  Their proposal
addresses many social and financial factors as well as provides major
engineering design elements and outlines the major systems and physical
characteristics of their ideal proposed layout.

\emph{The Modern Metropolis} consists of a series of Hans Blumenfeld's
essays and articles on urban growth versus urban
planning\emph{\cite{modernmetropolis}.}  These treatises generalize how
cities have developed and evolved over the decades and centuries, and
suggests some design principles for sustaining growth over time. These
insights into how to cope with the forces that incrementally shape
cities and inevitably stress them beyond their initially planned limits
reinforce some of the ideas for flexibility provided by Dantzig and
Saaty's design.

\subsection*{Arcologies in the Media}
A good experiment in closed-system sustainability is Biosphere 2
\cite{biosphere2}.  Unfortunately, its primary experiment was widely
regarded by the public as a
failure\cite{biospherefailure,biosphereaish}. The facility has since
come under the management of Columbia University as a research lab.

The closest present-day developments resembling arcologies are scattered
around the world in various stages of completion. The truest in spirit
of arcology projects in existence would include Arcosanti and Cosanti,
the experimental communities arranged by architect and founding father
of the \char`\"{}Arcology\char`\"{} concept Paolo Soleri
himself\cite{arcosanti}.  These reduced scale experiments in the Arizona
desert are currently reported to be hovering around 5\% complete after
30 years of development.  Like the Biosphere 2, these developments have
shifted their focus into acting as urban
laboratories\cite{arcosantiacrl}.

While this apparent lack of enthusiasm and resounding success paints a
somewhat bleak outlook, the influence of these spearheading projects is
definitely spreading. Large scale proposals have been cropping up more
frequently, especially in population-dense Asia. Predictably, the
Chinese have a keen interest in the arcology concept, both for expanding
high-density urban areas\cite{frick}, and also in the form of
constructing sustainable communities that would address their growing
problem with semi-rural slums\cite{ecodesigns}. Several Chinese and
Japanese design firms have been promoting various skyscraper approaches,
such as the Ultima Tower\cite{tsui}, Tokyo's Sky City\cite{takenaka},
and the on-hold Tokyo Millennium Tower\cite{millenniumtower} (the latter
two are covered in Discovery Channel
documentaries \cite{TokyoSkyCity,TokyoMillenniumTower}).  Arcology.com
has a collection of other notable works and
proposals \cite{arcology.com}.

While excitement about radically redesigning urban forms hasn't quite
taken off in practice, other environmentally-friendly initiatives have
taken its place. Several publications focus more on modifying the design
goals of current city planners to incorporate more alternative forms of
transportation. The book and accompanying website \emph{Carfree Cities}
presents several concepts and examples that make urban areas more
pedestrian, biker, and transit friendly
\cite{carfreecities,carfree}. Most contemporary urban revitalization
works take this track of advocating increased use of multimodal
transportation in current city design to cope with the strains of
present-day metropolitan area growth. Many formerly suburban towns have
already been pursuing more pragmatic policies encouraging higher-density
mixed-use development. These philosophies go under the monikers of
{}``New Urbanism'', {}``Smart Growth'', and {}``Transit Oriented
Design/Development''. For example, following successes in implementing
this pattern in the Washington DC metropolitan areas of in Rosslyn and
Silver Spring \cite{epasmarthgrowth}, plans are underway to build higher
density mixed-use population centers off of existing transit stations in
Vienna \cite{viennagrowth,viennabattle} and to extend transit to
existing office and residential spaces in Tysons Corner
\cite{tysonsplan,Etlin2004}.  We'll likely see more of this type of
development in the near future, especially seeing as how the Supreme
Court has recently ruled to allow private homes to be seized for mixed
use and other commercial development \cite{eminentdomain}.  However, in
his article ``The Compact City Fallacy'', Neuman defines how and
cautions that higher density and other Smart Growth policies alone will
not guarantee that we will meet the goals of sustainable development or
even achieve progress relative to previous development patterns
\cite{compactcityfallacy}.

\section{Modeling and Design of Urban Environments}

What makes a city special compared to a cluster of businesses and
residences?  Hans Blumenfeld \cite{modernmetropolis} argues that a
metropolitan area attracts corporations and residents with highly
specialized skill sets.  Also, as the population grows, a wider variety
of niche businesses can sprout up and sustain themselves while catering
to a relatively small segment of the market.  So by this consideration,
a good metropolitan area draws businesses and populations to it by
maximizing the diversity and variety of specialized skills and jobs.
See Figure \ref{fig:Population-Skill-Distribution} for a visual summary
of these trends.  A larger, more developed metropolitan area
(represented by the green shaded area extending out from the smaller
blue shaded area) would have more positions requiring advanced degrees,
as well as offer more variety in terms of ethnic restaurants,
specialized services, \emph{etc.}

\begin{figure}[p]
\epsfxsize=4.0truein
\centerline{\epsfbox{figures/PopulationDistribution.eps}}
\caption{Population Skill Distribution
\label{fig:Population-Skill-Distribution}}
\vspace{0.30 truein}
\epsfxsize=4.0truein
\centerline{\epsfbox{figures/Geography.eps}}
\caption{Geographical Distribution}
\label{fig:Geographical-Distribution}
\end{figure}

Geographically, as cities grow in population, they often grow
``outwards'' in area before they growing ``upwards'' in density.  As
noted in Figure \ref{fig:Geographical-Distribution}, this typically
follows a pattern of {}``fingers of development'' that grow outwards
from the urban core along established transportation corridors such as
highways or waterways.  The result is that most metropolitan areas
eventually become victims of their own success.  Drawing a more diverse
and skilled population eventually increases their geographical size
towards a point where a resident of the city can no longer access all of
the resources the urban area has to offer due to congestion.

\subsection*{The Role of Transportation Networks in Urban Environments}
Most of our interactions with the urban environment that we live in,
such as going to work, catching a bite to eat, buying groceries, or
ironically even going out for a hike, involve transportation and
delivery networks.  These systems take many forms, ranging from various
ground, air, and subterranean transit networks to power, water, and even
information distribution pipelines that feed directly into each of our
homes.  Much of this infrastructure is put in place with funding or
regulation from government agencies at national, state, and local
levels. During times of rapid modernization, traditional governments can
be a bit slow in figuring out what infrastructure to invest in.

\subsection*{Urban Design from a Systems Perspective}
An advantage to designing cities from the complete-systems perspective
of an arcology is that it forces you to take all scale levels --
national, metropolitan, urban, neighborhood, personal -- into account in
the design. This would allow the arcology to transition better as new
technologies evolve and are put into place. The physical aspect of an
arcology is predicated on a municipal ``hyperstructure'' which could be
sectioned off for residential, commercial, industrial, and civic
use. The sectional lots would have tightly integrated people and package
transportation in addition to the standard complement of water,
utilities, and a more minimal road network.

On the {\bf national level}, arcologies would be constructed to connect
well to other cities, with effective transportation and distribution
systems and quick transit times to most major destinations. Current
cities tend to have suboptimal transportation facilities. Many cities
originally sprouted up around ports by major waterways, where maritime
shipping accounts for over 90\% of the tonnage of U.S. international
imports and exports\cite{GAO-02-775}. However, domestically we move
freight predominantly by truck\cite{BTSmodes}. The United States has
invested heavily in the interstate highway system. Around many cities
these get tied up in rush hour congestion, resulting in delays and waste
throughout. High speed rail is an option that works well in most of the
rest of the industrialized world, but has languished in America.
Airports are usually built too far from the city to connect easily to
mass transit systems, and eventually get enveloped (and subsequently
throttled) by suburban growth after which they become a noise nuisance
to residents.

On the {\bf metropolitan level}, rush hour congestion itself is an
abomination that any commuter would readily identify with. We must look
terribly silly to outsiders, repeatedly stressing our transit
infrastructure past the capacity limit where it ceases to be
effective. We tend to want to commute simultaneously simply to be in
sync with everyone else - even those whom we don't even need to deal
with during the workday.  Dantzig and Saaty have dubbed this phenomenon
as ``cicadian rhythms'' and have noted that it also applies to water and
energy utility usage.  They have outlined the very simple remedy of
staggering a population's daily schedules, which is attainable once a
community reaches a sufficient size to support commercial staffing
arrangements into several shifts.

The U.S. metropolitan growth paradigm of roughly the last half-century
has been characterized by suburbanization. Affordable housing seems
to be in such short supply and fuel prices had been so low that many
chose to commute into job centers from suburban or exurban towns 30,
60, 90 miles away. Financial policies strongly encourage citizens
to purchase homes and enter into mortgage agreements. This provides
economic stability in the workforce, helping to affix them down in
a geographic area and ensure they stay gainfully employed to keep
up with mortgage payments. However, in today's increasingly unstable
job market, this policy can have adverse effects as a workforce with
impaired mobility will not have as much flexibility to take on employment
that maximizes use of their skills.

So as more massive superhighways are built to relieve the strain on the
original interstate connectors, more suburbanites continue to sprawl out
along these new corridors. After a certain point, the ratio of space
allocated between highways and developable, livable area becomes
saturated to the point where we get diminishing returns from building
more roadways. High capacity highways take up a lot of space relative to
streets, and when we start to pack those highways close together, we end
up spreading out actual useful land into isolated pockets nestled
between interchanges.  Looking down on our cities from above, we'd find
that most have more land area allocated to paved roadways for cars to
drive across than space for humans to go about their affairs
\cite{compactcityfallacy}.

To their credit, automobiles are certainly the most flexible mode of
transportation. All you need is a slab of pavement or even gravel
connected to the nearest street, and you now have an interface to the
``intercontinental road transportation network''. Compared to the
equipment you'd need to interface with the municipal power grid or
water/sewer lines, this slip of asphalt is likely one of the simplest
yet most capable ways of moving people and products to and from your
home. However, when be build cities almost exclusively around automotive
transport, we end up losing a lot of what makes dense cities good for
people and sustainable for the environment. Cars act as a multiplier to
the amount of space each person takes up. Not only do you need a
driveway space to park each person's car at their home, but also a space
reserved at their work, as well as some shared spaces at all of the
shops and venues at which they'd possibly spend time. Add to this the
ganglia of roads connecting those parking spaces together, shoulders for
emergencies, extra lanes for additional peak capacity, and of course
spacious service stations, and we find that our cities have vastly
outgrown the human scale. A transit-oriented city would provide more
land use for people by introducing transit alternatives that allow them
to travel between home and work from door-to-door. Park-and-Ride
initiatives connecting to mass transit accomplishes little in regards to
improving land utilization, since they do not eliminate parking spaces,
only relocate them further away from the workplace. In an urban complex
with sufficient transit, people should only need to use (or borrow) cars
to leave the city, and rely on transit to move people and goods within
the city.

As the urban area grows, we attempt to preserve an ideal population
density while also preserving the practical reach of the transit system
to prevent fragmenting the city.  For civic planning authorities, this
traditionally involves zoning and building out roads and utilities.  At
some point along the city's growth, they might consider the efficiencies
of building infrastructure based on a futuristic arcology hyperstructure
in order to meet their urban development goals in a compact physical
package.


On the {\bf personal level} most home infrastructure for living does not
have much flexibility for change. We are still using much of the same
basic physical interfaces developed over a century ago for power and
voice communications. Additional systems have sprouted on top of and
alongside these networks, such as DSL over existing telephone wiring,
cable television, and various wireless and satellite networks.  Add to
that various combinations of buried water mains, sewage systems, natural
gas pipelines, and perhaps we might begin to appreciate the need for
developing more flexible and maintainable utility distribution and
interconnect standards. The new standard interconnects would provide
room for expansion and serviceability, supporting the adoption of
emerging new infrastructure networks and allow easier retrofit of older
homes and living spaces. Such standards help reduce the barriers to
market entry, allowing economical deployments of upgrades such as
fiber-to-the-premises or even some things for which markets haven't
really been created for yet, such as the fully-automated package
delivery systems or centralized HVAC services referred to by Dantzig and
Saaty \cite{compactcity}.

\section{Simulation and Optimization of Urban Environments}

\subsection*{Simulation of Operational Concepts}
Simulation is one tool that can help quantify the benefits of different
operational concepts, which in turn can help answer questions about
design options.  A common engineering practice is to first document and
construct a baseline validated simulation of the system you have in
place, then extend the simulation with new proposals for changes to
equipment or operation. After analysts have evaluated the performance
benefits projected by different options, engineers could make a
decision, implement the change, and then re-validate the simulation to
make sure their model matches the performance of the modified actual
system.  Unfortunately, few municipalities maintain validated simulated
representations of their jurisdictions, much less use them as decision
making tools, deferring more towards the use of surveys and standalone
analytical teams. Building such a tool would not only give them better
access to information about the physical arrangement and performance of
their existing town, but could also be used as a ``vision communication
tool'' to the populace in order to cut down on some of the arguments and
political delays.

\subsection*{Simulation as a Decision Support Tool}

Several initiatives are currently underway to rethink the way
metropolitan areas are designed.  This simulation modeling and analysis
framework can provide a design planning and evaluation tool to assess
several integrated mass transit paradigms such as busing, rail, and
PRT-type (personalized rapid transport) networks to help
identify and accelerate acceptance of the worthwhile investments.

The use of simulation as a decision-support tool could provide a measure
of accountability that would help avoid or at least temper some of the
larger controversies over the past century of rapid technological
change. The history of our infrastructure has been peppered with some
epic and ultimately costly battles over different modes of transfer,
such as the turn of the century Edison - Tesla battle to establish AC or
DC as the power delivery standard \cite{ACDC} or the politicized finger
pointing over whether GM was duly responsible for taking control of
streetcar operations in the 20s in order to dismantle them in favor of
GM-manufactured buses \cite{Slater97,Cosgrove05}.  Having detailed
records of the simulations used to provide hard data on which broad
policy decisions are based could help justify your decision later. With
more exotic options pushed by several technology firms, we ought to
determine the selection of major communications upgrades or transit
systems based on available technical data, and not on which company has
the best connections to the civil servants responsible for municipal
decision making.

Ultimately, if this were to evolve into a fully-featured urban
simulation tool, it could be used as a rapid prototyping environment for
proposals to system changes big and small. When this functionality
matures, a municipality might require a simulation-based analysis to
accompany any new infrastructure proposal as part of a gateway approval
process.  As standard patterns are built up, the simulation framework
may morph into a design tool, replete with a library of openly available
blueprints, guidelines, and standards (as well as freely customizable
sections) to that can be assembled to achieve development goals.
Furthermore, as the process becomes automated, it might incorporate more
direct civil input, turning review and evaluation of problem areas and
proposals into something of an experiment with direct digital democracy
governance, in which the citizens can interact as something like a
hive mind.  Or so goes the vision.


\subsection*{Urban Simulation in the Media}
Previous well-known works that tackle the task of urban simulation
includes two series of open-ended games from Maxis (now part of
Electronic Arts) that approach the problem from different scales:
SimCity and The Sims. Certain versions of SimCity (2000 and 3000) even
had actual arcology units in them (although since they were entirely
self-contained, they really added little to the game play other than to
provide an easy way to boost your population tax base).  To some extent,
these games could be used to experiment with different urban or
residence layouts, but they primarily pattern themselves after common
current day paradigms and lack the flexibility needed to really turn its
simulated environment into useful data. Hopefully these games will serve
to influence the next generations of urban planners and administrators,
who might come to expect and demand some of the streamlined user
interfaces to command, control, and instantaneous reporting of city
condition and resources. Beyond that, there is not much published in the
way of complete city and/or lifestyle simulation. This might be the case
partly because most analysis can simply be done on spreadsheets using
historical data tracked by government agencies, and partly because most
simulation programmers are still busy developing their craft while
simulating more interesting things such as data \cite{ssfnet} and
transportation networks \cite{CITYSIM}.


\subsection*{Optimization of Mass Transit Operations}
The purpose of the optimization tool embedded within the simulation is
to provide some measure of intelligence that could demonstrate an
advanced, demand-responsive modeling scheme.  We'd use this flexibility
to investigate the potential effectiveness of various mass transit
paradigms, especially with regards to network topologies and their
ability to model:

\begin{description}
 \item{\bf 1.}  The distribution of various loads generated by work
	    nodes and residential nodes.
 \item{\bf 2.}  The size and connectivity constraints of various shared
	    vehicle networks shuttling people and goods between nodes.
 \item{\bf 3.}  The ability for the passengers and cargo to make
	    transfers between different vehicles as well as modes of
	    transit.
\end{description}

\vspace{0.10 in}\noindent
Applying a schedule optimizer ensures that we evaluate different transit
paradigms on a level playing field.  Different transit schemes utilizing
rail, bus, and PRT styles of vehicle sizes and routing will get a fair
shake at providing the maximum theoretical performance possible given
the same physical construction constraints.  Each mode of transit will
have some measure of routing intelligence that should reflect the
optimization computing power that should become more pervasive in the
near future.  They would all operate with the benefit of an intelligent
central dispatch that characteristic of advanced transportation systems.
System operators will have the freedom to direct their fleet about the
network and pick up, transfer, and drop off groups of passengers as
necessary to meet passenger demand as quickly and efficiently as
possible with their existing resources.  Mass transit vehicle fleets
will only be subject to the physical constraints of vehicle passenger
capacity, station berth / terminal / gate capacity, and the existence of
connective links between stations.

\section{Scope and Contributions of this Work}

This research and development project serves to realize an urban
multi-modal transit simulation designed during the course
of the systems engineering master's program.
The work takes a systems approach to modeling human
habitats and the transportation networks that keep them running.
The hope is that such a simulation framework will create a
baseline model of current day capacity, against which future models
may be evaluated with respect to performance and investment decisions.
The hypothesis of this work is that {\it these tools will be instrumental
in making a case for the development and construction
of highly efficient arcologies or other forms of well-integrated compact cities}.
But nominally, and for the meantime, urban multi-modal transportation
frameworks can be applied to the evaluation and tracking 
of present-day transit oriented growth philosophies.

Chapter 2 describes the formulation of a generic arcology system model
-- the result is a series of conceptual templates represented as classes
and relationships among classes.  Chapter 3 covers many of the practical
details one needs to consider in creating discrete event simulation
environments.  Chapter 4 is all about the specific commuting transit
system model analyzed in this work.  Chapter 5 contains simulation
scenarios, factorial design of experiments, and parametric analyses for
various mass-transit topologies.  The project conclusions and
opportunities for future work are covered in Chapter 6.

\vspace{0.1 truein}\noindent
{\bf Contributions.}
The contributions of this work are as follows:

\begin{description}
 \item{\bf 1.}  A hierarchical level-of-detail organization that allows
	    data from both top-down parametric models to interact with
	    data generated from clusters of detailed simulation
	    objects. This allows us to seed detailed objects in a
	    subsystem using available aggregate data from the live
	    system, and compare the live results to data generated by
	    tallying up the individual contributions from individual
	    simulation objects.  The hierarchical organization also
	    makes the simulation easier to partition across distributed
	    compute nodes.
 \item{\bf 2.}  Definition of a data interchange schema between elements
	    of a multi-modal transit infrastructure. The communication
	    provides just enough information about each piece of
	    passenger, cargo, vehicle , and connectivity graphs and
	    defines minimal interfaces to allow them to report to and
	    receive suggestions from a global transit optimization
	    engine.
 \item{\bf 3.}  An inherent focus on meeting the needs and goals of the
	    inhabitants.  Many transportation simulations focus on
	    maximizing throughput or minimizing delays or fuel
	    expenditure. However, these metrics may not serve to help
	    evaluate the layout of the urban area itself. This
	    simulation infrastructure would ideally be used to measure
	    the effectiveness of optimizing the layout of an urban area
	    to reduce the need to load the transit infrastructure with
	    commuters, people running petty errands, and other frequent
	    but necessary tasks.
	    
	    An ideal city would have a higher ``efficiency'' ratio,
	    tracked by an admittedly somewhat elusive ``productivity''
	    metric divided by the amount of energy directly needed to
	    produce it and energy overhead required to nominally sustain
	    production.

	    $\eta=\frac{GDP}{E{\scriptstyle _{direct}}+E_{sustinence}}$
	    
\end{description}


\vspace{0.10 in}\noindent
A simplified multimodal mass transit optimization solver coupled to the
simulation attempts to create a demand-responsive fleet schedule for
several types of defined vehicle types that service transit networks
within the simulation. This tool aims to provide a quasi-optimal means
to transport people and goods around within city clusters to help reduce
the overhead of the transit system.

% LocalWords:  arcologies hyperstructures BioSphere multimodal namespace HVAC
% LocalWords:  futurism Paolo Soleri superbuilding arcology's Dantzig com
% LocalWords:  Saaty Blumenfeld's Saaty's sustainability Arcosanti Cosanti DC
% LocalWords:  Ultima Carfree Rosslyn Tysons Neuman Blumenfeld truein exurban
% LocalWords:  hyperstructure developable DSL standalone morph Maxis SimCity
% LocalWords:  SimPy analyses WiFi upgradable cicadian PRT
