From: engelson-sean@CS.YALE.EDU (Sean Philip Engelson)
Newsgroups: comp.simulation
Subject: Abstract Robot Simulator available
Date: 6 Nov 1992 10:11:02 -0500
Organization: Yale AI Mobile Robotics Project
Distribution: world
Content-Length: 3308
X-Lines: 89




			    Now Available
			    ~~~~~~~~~~~~~

			      ARS MAGNA
		     The Abstract Robot Simulator
			   Sean P. Engelson
		    Department of Computer Science
			   Yale University

ABSTRACT:
~~~~~~~~
AI planning research has historically operated in formal abstractions
of the real world.  This approach was useful in discovering many
fundamental issues underlying planning; also, problems in simple
domains such as the blocks world can turn out to be surprisingly
difficult.  Lately attention has turned to planning for more realistic
domains in which micro-world simplifying assumptions do not hold.
This shift of focus introduces a new problem of validation and
comparison of different planning theories and systems.  A proper
domain for planning problems must be realistically complex but also
simple enough to support controlled experimentation.

To address these questions, we developed the ARS MAGNA robot
simulator.  The simulator provides an abstract world in which a
planner controls a mobile robot.  Mobile robotics is a particularly
apposite domain since it is a major application area for AI planning
techniques.  ARS MAGNA's environment and robot models are based on
current robotics research, so that the domain is reasonably realistic.
At the same time, we abstracted away from many (though not all)
real-world details of kinematics and motor control.  Experiments may
be controlled by varying global world parameters, such as perceptual
noise, as well as building specific environments in order to exercise
particular planner features.  The world is also extensible to allow
new experimental designs that were not thought of originally.  The
simulator also includes a simple graphical user-interface which uses
the CLX interface to the X window system.


DOCUMENTATION:
~~~~~~~~~~~~~
Version 1.0 of the ARS MAGNA simulator is documented in Yale Technical
Report YALEU/DCS/RR #928, "ARS MAGNA: The Abstract Robot Simulator".
This report is available as a Postscript(tm) file both in the
distribution and separately via ftp as pub/TR/tr928.ps.Z.  Hardcopies
are available from Yale University (Paula Murano, murano@cs.yale.edu).
Any and all comments would be most welcome.


AVAILABILITY:
~~~~~~~~~~~~
ARS MAGNA can be gotten by anonymous ftp from ftp.cs.yale.edu, as
ars-magna.tar.Z in the pub/nisp directory, as follows:

% ftp ftp.cs.yale.edu
Connected to dept-gw.cs.yale.edu.
220 ra FTP server (SunOS 4.1) ready.
Name (ftp.cs.yale.edu:engelson): anonymous
331 Guest login ok, send ident as password.
Password:
230 Guest login ok, access restrictions apply.
ftp> cd pub/nisp
250 CWD command successful.
ftp> bin
200 Type set to I.
ftp> get ars-magna.tar.Z
200 PORT command successful.
150 Binary data connection for ars-magna.tar.Z (128.36.17.10,1220) (528589 bytes
).
226 Binary Transfer complete.
local: ars-magna.tar.Z remote: ars-magna.tar.Z
528589 bytes received in 7.4 seconds (70 Kbytes/s)
ftp> quit
221 Goodbye.
% uncompress ars-magna.tar.Z
% tar xf ars-magna.tar
%

Installation instructions are in the file Installation.readme.  The
simulator is written in Nisp, a macro-package for Common Lisp.  Nisp
can be retrieved in the same way as the simulator.  

 -- 
Sean Philip (Shlomo) Engelson		
Yale Department of Computer Science	
Box 2158 Yale Station			
New Haven, CT 06520			



------------------------------


Subject: [DEPARTMENTS]


------------------------------


Date:    Thu, 5 Nov 92 19:27:14 GMT
From: mcleod@Sdsc.Edu
Subject: E-S3 Vol.1 No.10 
Content-Length: 31444
X-Lines: 712

 
The following sample issue of our electronic magazine, "E-S3",
covering selected topics about computer modeling and simulation,
is sent to you with the compliments of the publisher of the
technical journal SIMULATION, the Society for Computer
Simulation, and John and Suzette McLeod, the Editors of
Simulation in the Service of Society (S3), a special section of
that journal.  If you do not care to receive future issues please
type REPLY -- cancel.  Let's not clutter up our E-mail with "Junk
Mail"!
__________________________________________________________________
                      E-S3  Vol. 1, No. 10 
                based on the Otober 1992 issue of
             "Simulation in the Service of Society"
John McLeod, Technical Editor     Suzette McLeod, Managing Editor
          8484 La Jolla Shores Dr., La Jolla, CA 92037.
                   E-mail: mcleod@sdsc.bitnet
                                *
                   S3 is a special section of
                           SIMULATION
                   the monthly journal of the
                 SOCIETY for COMPUTER SIMULATION
             P.O.Box 17900, San Diego, CA 92177-7900
            Phone: (619) 277-3888 FAX: (619) 277-3930
                                *
[Copyright  Notice:  E-S3 is the electronically delivered version of
"Simulation in the Service of Society" which is a special section of
SIMULATION, a monthly technical journal of the  Society for Computer
Simulation International. It may be reproduced only for personal use
or for the use of students. In any case full credit must be given to
the original source of publication: SIMULATION  59:4, October 1992. 
    All rights reserved, (c) 1992, Simulation Councils, Inc.]
 ----------------------------------------------------------------------
 
MISSION EARTH 
 
The Inspiration
 
	Under the heading REPORT in this column in the September 
issue we wrote "After a lively and progressive discussion, kicked 
off by Ben Clymer giving excerpts from his excellent and 
perceptive Position Paper ... some facts became clear ..."
 
	The following is an update of Ben's paper, which was 
instrumental in launching what has become SCSI's project MISSION 
EARTH, our effort to better understand, and thus be in a better 
position to alleviate, our many environmental problems.
 ----------------------------------------------------------------
                      "Specifications for 
                 Simulations in Planet Planning"                               
                               by 
                          A. Ben Clymer 
                    32 Willow Drive, Ste. 1B 
                         Ocean, NJ 07712
 
 
	John McLeod, founder of The Society for Computer 
Simulation, has called upon simulationists to address seriously 
the question of how to use simulation as the preferred tool for 
planning the saving of our race and planet. This Panel and its 
associated position papers constitute just one step toward that 
goal.
 
	This paper is an extension of the author's position 
statement for John's session at the 1992 SCSC. It includes a 
description of the SCS Technical Activity called Mission Earth 
and its plans for action on behalf of mankind and the planet's 
other organisms. Included in the references are the author's 
previous publications relevant to Mission Earth, which indicate 
his long and broad interest in the problem.
 
       Many writers, too numerous to cite, have pointed with 
intense alarm to the desperateness of the situation in which we 
find ourselves globally. The planet is in distress. We have 
despoiled our environment totally, in scope if not yet in amount.
 
	Already the consequences of our irresponsibility are 
grave, and they are increasing rapidly in severity. The problem 
is compounded by the don't care attitude of many people. One can 
easily extrapolate to the planet becoming uninhabitable for Man. 
Not only that, but the human population is fast becoming grossly 
excessive for the space and resources even now available. We are 
leaving to future generations a highly undesirable, if not 
impossible, problem to deal with in order just to live.
 
	There is a substantial history of previous attempts to 
put things right through simulation studies. The groundbreaker 
was Jay Forrester's 1970 proposal to the Club of Rome to simulate 
man's activities over the entire world and over a long time into 
the future (Meadows et al. 1972, 1973, 1974). Subsequent 
simulation studies by others elsewhere (notably Mesarovic and 
Pestel) since then have added variables, details, and size to the 
MIT model. However, the main outcome seems to have been 
expression of an "ain't it awful" feeling, with minimal regard 
being given the matter and with virtually no positive action 
being taken by the hierarchy of governments. It has been 
difficult for observers to entertain any hope of victory by Man 
over himself. 
 
A. Mathematical Aspects
 
1. Purposes of Simulation for Planet Planning
 
	There are numerous purposes for which simulation can and 
should be used in planet planning including the following:
 
	1. To learn more about the system. There is much that we 
do not know, to the point that some organizations abandoned their 
attempts at world simulation (D. H. Meadows 1985).

	2. To get initial conditions for simulation runs by 
simulating the recent past. These runs also can be checked 
against available historical and current data as partial 
validation of the model.
 
	3. To educate all personnel about the system and plans. 
These persons include managers on all levels of the global 
hierarchy of government and environmental management, 
simulationists with all levels of skill and experience, 
journalists, the public, etc.
	
        4. The main purpose of simulation is to try out a large 
variety of plans that are being considered. The simulations 
include an evaluation of all quantities that are involved in 
judging each plan.
 
	5. Simulations are needed to provide detailed 
documentation of plans that survive the evaluations. The results 
will provide accountability for the decision makers.
 
	6. The same plan can be evaluated for different times of 
initiation, in order to see the costs of delay. Then urgencies of 
actions will be known.
 
	7. Simulations can be used to determine the sensitivities 
of important results of various details in the system or in 
plans. Then one can decide when enough improvement of accuracies 
of input data has been done.
 
	8. Simulations can be tested against particular data to 
identify where knowledge of the system model is inadequate. 
Simulations can uncover ignorance.
 
	9. Simulation can be the inner forward path of complex 
optimization loops, as explained next.
 
2. The Overall Optimization Problem
 
	The overall problem of planet planning is incredibly 
complicated. It is hierarchical, which makes it necessary for 
each plan to have essential content in every echelon of the 
hierarchy. It is long-term, which requires that every plan be 
extended many years into the future. It has a multitude of 
aspects that interact, such as human population, environmental 
integrity, ecological stability and diversity, economics, 
political concerns on every level of government, quality of life 
for humans and other species, sustainability against disturbances 
not under control, etc. 
 
	It is an optimization problem, which requires that a 
hierarchy of value functions be designed and argued through to 
acceptance. It is an expensive undertaking for which no political 
entity is prepared to pay its share. It involves constraints, 
such as finite amounts of resources. 

	It is a global problem, which requires that many models 
be developed on a global scale. It is a global problem also in 
the sense of having to divide up the simulation work among many 
nations having different languages, values, etc. There is a 
rapidly approaching deadline for completion of study and 
planning, after which only minor battles, if any, can be won.
 
	Really, in the light of past undertakings by cooperative 
simulationists and governments, it is too much for us. However, 
the alternative is progressive and rapid extinction. Will 
realization of the need cause an adequate response by mankind?
 
	One way to look at the problem is that of Peter 
Seligmann, who speaks of the "nexus between people and nature", a 
network to be augmented and perfected by us in the form of 
control systems. It will protect nature and people.
 
3. Input Data Needed
 
	A few key kinds of data will be mentioned here. One is 
the kind of details that go into such composite indices as the 
Gross National Product. The GNP should not be used at all, 
because it does not reckon from a broad enough standpoint. For 
example, it does not consider the costs due to ravaging of the 
environment, using up scarce resources, etc. New indices need to 
be developed.
 
	The following is a classification of most of the 
variables of concern:
 
	1. Populations: initial conditions; births, deaths, and 
migrations
 
	2. Ecosystems: status of species populations and 
environmental variables
 
	3. Atmosphere: composition input rates, chemical 
kinetics, radiation throughputs
 
	4. Natural resources: absolute inventories, costs of 
progressive recovery
 
	5. Materials: matrix of fluxes through industry, 
pollutants generated by industry
 
	6. Food: production distribution, soil conditions, animal 
and fish availabilities
 
	7. Fresh water: pollution processes
 
	8. Ocean: composition, movements, atmospheric coupling
	
4. Final Steady State Conditions Desired
 
desired other than that an ultimate optimum state of the earth be 
reached by a given date. Granted that some desideratum more 
sophisticated than that will be wanted in the long run, this end 
condition is a good enough one for the sake of the present 
discussion.
 
	The earth state is described by geographical hierarchies 
of many variables: populations, energy usages, remaining natural 
resources, quality of life, etc. The one most often discussed and 
perhaps the most important is total world population and its 
hierarchical distribution. Usually it is coupled with the 
intended date of achievement. Various world populations have been 
suggested as sustainable: 2-3 billion (Ann and Paul Ehrlich), and 
1-2 billion (Roderick Frazier Nash). These numbers, being much 
lower than the present world population, might never again be 
achievable.
 
5. Systems to be Simulated
 
	There are many systems that need to be simulated with as 
much coupling as can be handled. One possible breakdown of the 
overall system would feature population, economics, resources, 
pollution, and quality of life (Susan Merrow).
 
	Another breakdown of the system for purposes of 
simulation would feature land management, water management, 
atmospheric management, and space management. The following 
remarks indicate what should be included and what some of the 
major problems are:
 
	5.1. Land Management
 
	Individual terrestrial ecosystems (forests, grasslands, 
tundra, etc.) deserve to be simulated in their actual 
surroundings. The notable problems include control of timbering 
and mining, fires, acid rain and its effects, erosion, 
desertification, fertilizer and pesticide usage, tilling 
practices, results of commercial incursions, interaction with 
rainfall, tree planting optimization, reductions in species 
diversity, extinctions of varieties and species, protection of 
rivers from nonpoint source pollution, etc.
	
	5.2 Water Management
 
	These simulations should be by individual water bodies 
wherever feasible, using lumping elsewhere. Some of the 
freshwater management problems are allocation among would-be 
users, fish kills, purification requirements as related to 
intended uses, ecosystems species diversity and health, pollution 
prevention and cleanup, acid rain effects, effects of pollution 
upon wildlife, consequences of losses of wetlands, etc. 
 
	Some of the ocean problems are pollution by ships and 
shore-based discharges, major oil spills, rise of water level due 
to global warming, ocean-atmosphere thermal and flow 
interactions, beach dynamics and barrier island management, 
distillation to obtain potable water, etc. There are serious 
problems also with ground water, which suffers pollution from 
solid waste dumps and sewage disposal, and which is by far the 
largest reservoir of fresh water (hence deserving of the best 
protection).
	
	5.3 Atmosphere Management
 
	The atmosphere too is in need of simulation studies to 
evaluate such phenomena as local and global warming and/or 
cooling by the effects of various gases, the industrial processes 
producing those gases (including agricultural industry cow 
belches of methane), the ozone layer kinetics, urban air 
pollution (smog, brown air), weather and climate management (if 
and when feasible), acid rain transport and chemistry, wind-borne 
radioactivity, fate of solid wastes burned, atmospheric motions, 
temperatures and chemical reactions as in weather prediction, 
etc.
 
	A separate list could be made of phenomena in the region 
of the atmosphere but not directly associated with the gases 
there, such as cancer-causing effects of electric power at 
frequencies at or below 60 Hz (if indeed there are such effects), 
ultraviolet light, X-rays, etc. Higher up, we should be worried 
about the growing proliferation rate of space junk orbiting the 
earth. 
	
	5.4 Other Hierarchies
 
	There is no single hierarchy that can comprehend all of 
the systems to be simulated. Many hierarchies will be useful. 
One of the most important is the geographic hierarchy of 
human population dynamics. It spawns the principal despoilers of 
the planet. It is these creatures that destroy natural 
ecosystems, kill each other and vast numbers of other creatures, 
pollute the land and water and air, create gases that change the 
properties of the atmosphere for the worse, use up critical 
materials, waste energy, obtain energy from relatively 
inappropriate sources, use lawyers to write laws and other 
lawyers to find loopholes, reproduce at rates making populations 
that overwhelm the possible production of food, without any 
lasting or effective restraint by governments, reward criminal 
behavior, buy governmental representatives, and otherwise also 
are the worst "bad actors" in our world. 
 
	Other hierarchies that need to be simulated in detail are 
the economic system (geographic hierarchy, and by industry, etc., 
including the causes and effects associated with greed and fear), 
the world and national and state governments, natural resources 
inventories (including estimated possible future substitutions), 
industries (as users of energy and materials, and as generators 
of products and pollutants), the hierarchy of laws worldwide and 
its trends, the worldwide hierarchy of morality and ethics for 
individuals and organizations, worldwide companies (each a 
hierarchy having effects upon many other hierarchies), the 
financial system (international loans and repayments, control of 
currencies, research and demonstration projects, etc.), etc.
	
6. Simulation of Planet Planning
 
	The process of analyzing, simulating, and planning planet 
management deserves to be simulated in the interest of improving 
the process. The planning of this work should answer the 
questions raised by McLeod: who, for whom, do what, and who pays?
	
Perhaps the stickiest part is cost. Cost rises faster 
than linearly with improvement of the system to be managed. Hence 
the choice of a level of improvement and cost will have to be 
debated and resolved. The question cannot be answered 
satisfactorily in the absence of many simulations, each of which 
includes a price tag found as part of the simulation. Debate 
based on present knowledge is a waste of time. 
 
	Most Americans want to protect and improve the 
environment. The US now spends less than 2 cents per dollar on 
the environment.
 
	One of the best ways to raise money for governmental 
purposes is taxation of the people most concerned with the 
problem to be fixed. "Tax policy is one of the most potent 
instruments to move the world in an environmentally sustainable 
direction" (Brown). Taxes can be used to encourage some actions 
while discouraging others. In a given country the system of 
taxation can be organized as a matrix of monies needed for groups 
of purposes vs. groups of people targeted. The matrix is not 
diagonal. 
 
	The hierarchy of tax matrices is just one element of 
concern in planet planning. However, there is not complete 
freedom in manipulating these matrices, as evidenced by the fact 
that ". . . 61% oppose raising new taxes specifically targeted to 
the environment", although they would be willing to get the money 
by raising some existing taxes (Anon.)." 92% believe a balance 
between environmental protection and economic development can be 
attained. . . . Only 10% believe (environmental protection) . . . 
has gone too far" (Anon).
 
B. Managerial Aspects
   
1. Philosophy
     
   1.1 Some Negatives
 
	The present situation has stemmed largely from the 
uncontrolled exercise of many human character defects throughout 
the past.
 
	1. Columbus and his men set the tone for the Spanish 
conquest of the Americas by being individually greedy and lawless 
robbers, murderers, rapists, etc., feeling that their superiority 
(as they perceived it) entitled them to take their pleasure with 
everything they found (Lopez). In addition there was no one to 
stay their hand. This is the behavior of many people when they 
consider punishment to be unlikely. It is the age-old 
exploitation of the weak by the strong. 
 
	2. Even today in every country we have a "dysfunctional 
civilization." That "civilization" has been having a collision 
with the world, and we are just beginning to witness the response 
of civilization to its own destructiveness (Al Gore).
 
	3. Today's commerce shares the blame: "A large part of 
the natural world has been damaged or destroyed by unregulated 
commerce" (Ehrenfeld).
 
	4. "We must quit being selfish, greedy, and violent" 
(Wendell Berry).
 
	5. ". . . there is no political concern more important 
than putting a stop to the massive damage we are doing to the 
earth and its atmosphere, and to accelerating population growth" 
(Al Gore).
 
	6. As we play God with our world we should try to 
maintain a realization of our analogy to the Spaniards of the 
1500's in the New World.
 
   1.2 Some Positives
 
	We need to be very choosy about the type of stewardship 
that we give our world. Our record with aborigines and their 
environments has been poor, starting with well-intentioned 
missionaries and continuing with business men. To be guided by 
ecologists would be mostly good for ecosystems and perhaps 
peoples, but there could be an unreasonable price. We need to be 
responsible in the eyes of all parties.
 
	We must try to restore some of the balance between the 
welfare of society and the health of the planet (Peter 
Seligmann). Seligmann feels that "the only route to conservation 
is through understanding how people can respect and live 
harmoniously with nature". Again, in the words of Aldo Leopold,  
"... the earth is a community to which we belong, not a commodity 
it is our privilege to exploit" (quoted by Wallace Stegner).
 
	Some special people must lead the way. According to Al 
Gore, "... free men and women who feel individual 
responsibility for a particular part of the earth are, by and 
large, its most effective protectors, defenders, and stewards." 
The publishers of and contributors toward ORION and other 
conservation magazines are "... a dedicated group of people 
working toward a new, deeper relationship to the land and its 
inhabitants" (Charles Grayson). However, many more people will be 
needed, notably in our field of simulation. In addition, "We have 
to convert concerned individuals into environmental activists" 
(Brown). We must preach to all the necessity of biophilia (the 
love for all living things and their environment) (Lopez).
	
2. Hierarchies of Organizations Needed
 
	An organized and structured plan is needed for executing 
the work of planet simulation. One trouble is the large number of 
organizations that should be involved in some way: the United 
Nations, governments on every level, universities and research 
institutes, ecosystem management organizations, financial 
institutions, etc. The solution must tie them together in ways 
that will make for acceptable cooperation and productivity. No 
single hierarchy can accommodate them. 
 
	Undoubtedly universities will have to do the lion's share 
of the modeling and simulation. However, they will require 
outside funding from a variety of types of sources: grants from 
their own governments on every level, grants from financial 
institutions such as the World Bank, project support by 
industries concerned, token payments from countries unable to 
contribute otherwise, etc. Some support might be possible from 
the nonprofit organizations which are defending the environment, 
seeking to throttle population increase, etc., with funds 
provided by individual members not otherwise coupled into the 
problem. National and state laboratories can cooperate. 
Industrial laboratories can help too.
 
	It will be important to simulate every square foot of the 
earth one way or another. There will inevitably be duplications 
and overlaps, but there must not be gaps left uncovered, either 
geographically or functionally.
 
3. Management of Ecosystems
 
	Each ecosystem needs to be simulated as a whole, embedded 
in its surroundings. Endangered species are especially important 
elements. Protection of the ecosystem from all known threats 
should be simulated. War is the worst threat to any ecosystem 
(Frederik Pohl), and wars are always countable in the dozens 
around the world. All "bad guys", such as poachers, need to have 
their hands tied, down to some maximum allowable probability that 
their actions will be disastrous. Slow demise of an ecosystem 
from rim inward due to edge effects must be studied and plans 
devised to oppose such loss.
 
	Ecosystems might always be lost due to imperfect 
management. If one fails, then any industry which had been 
dependent on it must be phased out or moved. Thus lumbering must 
be closed down on a forest ecosystem that has been too gutted to 
continue or to be renewed as a forest. Likewise, commercial 
activities in a National Park need to be limited, or shut down if 
legal limits on such activities are exceeded by illegal means, 
such as corruption of officials.

	"Americans are relatively content with the amount of wild 
or natural areas available for their use" (Anon.). Frederik Pohl 
would stop allowing changes in land use, especially in the 
direction of development. If such a change were suddenly imposed, 
it would wreak havoc with such industries as construction and 
real estate, but the time must come when limits are actually 
imposed and enforced, however gradually.
 
	Tropical forests have been the object of several 
constructive suggestions. One is to establish extractive reserves 
(i.e., forest setasides which can be worked nondestructively for 
fruits, rubber, nuts, medicinals, button materials, fibers, 
etc.). Another is agroforestry, in which special agriculture is 
practiced within and without damage to the forest. Another is the 
general category of sustainable development, in which nothing is 
destroyed or used up while commercially valuable materials are 
taken out. In all of these cases the natives are an excellent 
source of information about uses of natural materials. In all of 
these cases it is important to reward those peoples living in the 
forest by means of an equitable share of profits.
 
C. Conclusions
 
	1. The need is for about two orders of magnitude more 
effort than will actually be expended, even with Man's best 
efforts to organize for an emergency.
 
	2. The Society for Computer Simulation should take the 
lead in promoting and guiding the effort.
 
	3. The key tool in support of planet management is 
simulation.
 
	4. The simulations required must encompass several 
hierarchies of systems, many hierarchies of proposed plans, and 
an overall optimization loop (for which the value function must 
be decided upon early on).
 
	5. The whole world of peoples must become involved to 
various degrees and in various ways.
 
	6. Most of the needed simulations must be developed 
almost from scratch. Much basic information is unknown. However, 
simulation is an excellent way to identify and correct ignorance.
 
	7. We must keep in mind the alternative.
	
        8. The failure phenomena that have been studied and 
analyzed by William Livingston are sure to crop up in the larger 
simulation efforts, especially those involving several 
organizations.
 
D. Actions by SCS
 
SCS, the Society has taken some positive steps toward fulfilling 
its needed role on behalf of the world.
 
1. Technical Activity, Mission Earth
	
A Technical Activity called Mission Earth has been created under 
the leadership of Zoran Ilic. By virtue of this responsibility 
Zoran is an Associate Vice President of SCS. The plans for this 
Activity include the following.
 
	* Develop standards for hierarchies of global and other 
large models, simulations, and simulation run campaigns. Specify 
to the maximum feasible extent the technologies and techniques 
that should be used. A committee within the Activity will be 
needed.
 
	* Provide forums, at least quarterly, at which 
simulationists, scientists, and planners can communicate with 
themselves and each other. It is intended that each SCS 
conference henceforth will include a portion devoted to Mission 
Earth. Ben Clymer will head up this effort, which will be carried 
out by a permanent committee.
 
	* Monitor and search the literature for work of interest 
to Mission Earth. Disseminate it through appropriate channels. A 
whole team will be needed for this effort.
 
	* Find and communicate with the simulationists, 
scientists and planners now engaged in studies of concern to 
Mission Earth, or who might well be. Extend and strengthen the 
communication network among them. John McLeod will be doing some 
of this through his publication "Simulation in the Service of 
Society" and other channels. John has brought in Dick Chadwick, 
of the University of Hawaii, who has many important contacts in 
political science and global and regional simulation around the 
world. Perhaps the McLeod Institute could be brought in as a 
player, especially since it is growing worldwide and is respected 
in academia. 
 
	* The next meeting of the Technical Activity (Mission 
Earth) will be at the Western Simulation MultiConference in San 
Diego in January 1993. All who are interested are invited to 
attend, join up, and participate henceforth. The Activity will 
meet at each major SCS conference.
 
	* Financial support is being solicited for the Activity. 
The expenses of the Activity are estimated to be much higher than 
those of the other Activities now in existence.
 
2. Plans for Conferences
 
	* Winter Simulation Conference, December 1992. There is a 
possibility that a presentation will be made concerning the 
applications of discrete event simulation and combined 
(continuous and discrete event) to global problems, particularly 
in the softer sciences, although it is very late to be trying.
 
	* Western MultiConference, January 1993. Places in the 
program are currently being negotiated. It is late for this one 
too. This paper might be presented and discussed at length.
 
	* Simulation MultiConference, April 1993. If a program 
committee can be recruited in time, an attempt will be made to 
develop a full conference or track for Mission Earth. Also, a 
paper could be written to span the gap between "emergencies" and 
the long-term global daddy "Emergency" of them all, for 
presentation at the Emergency Management Conference.
 
	* Summer Computer Simulation Conference, July 1993. A 
full Group is intended for Project Earth. By then it should be 
possible to report major progress by the Activity and bring in 
many participants as authors and panelists.
 
	* European 1993: There is an SCSI conference in November 
1993 that might be suited to bringing together European 
participants in Mission Earth. It will be discussed with the 
European Office. A presentation could be made by an American 
participant.
 
REFERENCES
 
Anon., "Natural Resources: Can They Be Saved?" Golf, July 1992, 
pp 12-15.
 
Berry, W., see Stegner
 
Brown, Lester R., "Worldwatcher's Warning," World Monitor, May 
1992, pp 18-20.
 
Clymer, A. Ben and R. S. Davidson. "The Desirability and Applica
bility of Simulating Ecosystems" in Annals of the New York 
Academy of Sciences, January 1966, 128, 3, pp 790-794. 
 
Clymer, A. Ben. "The Modeling of Hierarchical Systems." Keynote 
Address, Proceedings of Conference on Application of Continuous 
System Simulation Languages, June 1969, pp 1-16.
 
Clymer, A. Ben. "The Hierarchical Approach to Public Problem 
Simulation" in SIMULATION, August 1970, pp 50-54.
 
Clymer, A. Ben and L. J. Bledsoe. "A Guide to the Mathematical 
Modeling of an Ecosystem" in Simulation and Analysis of Dynamics 
of a Semi-Desert Grassland, Range Science Department, Science 
Series No. 6, Colorado State University, December 1970, pp I 75-
99.
 
Clymer, A. Ben. "Next Generation Models of Public Systems" in 
Simulation Councils Proceedings, 1, 1, January 1971, pp 115-134.
 
Patten, Ed., Systems Analysis and Simulation in Ecology, 2, 
Academic Press, 1972, pp 533-569.
 
Clymer, A. Ben and J. C. Burr, "Air Modeling in Ohio EPA" in 
Proceedings of Conference on Environmental Modeling and 
Simulation, U.S. Environmental Protection Agency, Cincinnati, 
April 1976.
 
Clymer, A. Ben and R. G. Duffy. "Water Modeling in Ohio EPA" in 
Proceedings of Conference on Environmental Modeling and 
Simulation, U.S. Environmental Protection Agency, Cincinnati, 
April 1976.
 
Clymer, A. Ben. "Simulation of Living Systems Then, Now and When" 
in SIMULATION, August 1990, pp 97-102.
 
Clymer, A. Ben. "Simulations of the Environment" in Proceedings 
of Simulation MultiConference, Society for Computer Simulation, 
1991.
 
Ehrenfeld, D., "Raritan Letter," Orion, Summer 1992.
 
Gore, A., "Interview by Jordan Fisher-Smith," Orion, Summer 1992.
 
Grayson, C., Letter, Orion, Summer 1992.
 
Livingston, W. (1990), Friends in High Places, F.E.S. Ltd. 
Publishing, New York.
 
Lopez, B. "The Rediscovery of North America," Orion, Summer 1992, 
pp 10-16.
 
Meadows, D. H., et al. (1972), The Limits To Growth. Universe 
Books, New York.
 
Meadows, D. L., and D. H. Meadows (1973), Eds., Toward Global 
Equilibrium: Collected Papers. Wright-Allen Press, Cambridge, MA.
 
Meadows, D. L. , et al. (1974), Dynamics of Growth in a Finite 
World, Wright-Allen Press, Cambridge, MA.
 
Meadows, D. H. (1985), "Charting the Way the World Works," 
Technology Review, Feb.-Mar., pp 54-63. (Includes a table of 
information about 20 global models.) 
 
Merrow, S., see Stegner.
 
Nash, R. F., see Stegner.
 
Pohl, F., see Stegner.
 
Seligmann, P., see Stegner.
 
Stegner, W., "Now If I Ruled the World," Sierra, May-June 1992, 
pp 114-142.



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