We would like to thank everyone who has responded to our request for
NEOS stories. Hopefully this page will provide an idea of the range of applications people are attacking with NEOS. If you would like to contribute to this page,
send us a message describing the problems or problem types you've solved with NEOS or fill out the form you will find by clicking the Comments and Questions button at the bottom of the page. The comments here are roughly categorized into Education, Business & Finance, and Science & Industry sections.
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Education |
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Thanks for the prompt reaction! I am currently developing a 100%
Java application to aid students to learn operations research. Since
the NEOS server is by far the best place on the web
where my students can submit their applications with the hope of
getting back trustable results, I am planning
to integrate the communication module.
I think that first we all should thank you and your colleagues
for the excellent work done with NEOS. It is a great service to the public.
I myself used it in trying out the AMPL interface for my code donlp2,
most of the other codes being installed locally here. But I know of
a colleague which uses NEOS as a teaching machinery for his nonlinear
programming courses, which could otherwise be done only by paper and
pencil due to the lack of appropriate computing resources.
I sincerely believe "optimization on the Internet", or some people refer
to it in more general terms: "providing decision technologies over the
Internet as services", is very important and will become ever more
important in the future. For "optimization" to become a viable tool for
the "end users", they must be provided with the latest optimization
tools in a user friendly manner. NEOS relieves the end users from
"software version updating" headaches and provides very friendly and
expert guidance on their problems. I thank you for an excellent service.
I require students in my senior project course to study OTC thoroughly and solve some optimization problems making use of the NEOS services. These problems can be solved with the software available in our university, but I do this in order to provide students with some experience on use of Internet for long distance technical collaboration. I also believe resources like OTC are excellent means for continuing professional development for my students.
I am using NEOS for solving problems and examples for the classes I
teach.
Faculdade de Ciencias da Universidade de Lisboa, DEIO
Thank you very much for BonsaiG.
I used it for my master's thesis at the University of Twente, where I
scheduled iterative algorithms on multiprocessor systems.
We are using the NEOS Server to design communication networks
and system state perception of control agents for large,
distributed networks, such as the power grid, at Carnegie
Mellon University.
We are using the NEOS Server for teaching AMPL and SIF
and solving tutorial examples of nonlinear optimization.
Some students are using the NEOS Server for solving
optimization problems when writing their Diplom-thesis.
Thank you very much for managing the NEOS-Server.
Thank you so much for your works at the NEOS Server.
We are using the NEOS Server for the research of Computer Network
and solving the Network Design Problem at Osaka University in Japan.
I used NEOS for a project in a grad-level cs class at Purdue Univ this
past fall, on a network flow problem.
I had students run some
examples using NEOS in three classes since you first announced
it. No one complained :-) The only difficulties I heard
about we of the i've-never-programmed-in-Fortran variety,
and those are not your issue.
Valuable service.
We are planning to use NEOS with the (still experimental) callback
features in inverse problems arising in multiphase reactionary fluid
systems in an interdisciplinary research project at the University of
Technology Aachen.
The only computation I have done using NEOS is for unconstrained NLP (NMTR),
application to train an artificial neural network (in a project
with an engineering student). I have also presented NEOS to third
year undergraduates, to introduce them to optimization software
for NLP especially, and referred 3rd parties to the NEOS website.
One of the main benefits of NEOS from my point of view is that
it provides a kind of one-stop-shop for people tinkering with
optimization models/methods, and is friendly enough for non-optimizers
to get along with.
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Education: Mathematics |
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Using the NEOS server in a class on Methods of Applied Math (Math511)
at the Math.Dept., Univ. of Tennessee.
It has been very useful. Keep up the good work!
We are using MINLP on the NEOS Server in a class on discrete design
and optimization at University of Michigan. I cannot run the class
without it!
We used the NEOS server for linear programming class at the University of
Wisconsin-Milwaukee.
I used the NEOS server as part of my course "Computational Methods
in Analysis" in both Fall 1998 and Fall 1999. There were 78 and
43 students enrolled, respectively. NEOS was used in a project to
explore and evaluate methodologies for "delivering" math software to
users. The students found that using the NEOS server was quite easy
(although there are always a few people who seem never to be able to
follow instructions) and they rated it as one of the more efficient ways
to access existing software for the optimization problem they were
assigned.
We are using the NEOS Server in a class on linear and nonlinear
programming at Ohio University.
We have used the NEOS Server in a class for deterministic optimization
in mathematical modeling at Saint Peter's College, NJ. I also use it
in an elementary finite math class as a lecture demo.
I am teaching Optimization techniques for students who want become
Diplom-Mathematiker. Our University is a University of Applied
Sciences and for our students it is important to formulate and to solve
optimization problems and it is not important to create new optimization
techniques. Therefore I give only an overview about the different
optimization techniques and then my students have to solve a wide
variety of different optimization problems; linear and nonlinear.
First the students are learning the MPS description of linear problems and then the are learning SIF. On our computers we have an old release of LANCELOT but I ask the students to solve the problems by using the NEOS server. Sending a problem to the NEOS Server, we usually received an answer in only few minutes. This is very good! I was also interested that my students use the helpful comments and suggestions on the various NEOS Web pages. The material is very good. My work is to be a moderator between the NEOS Server and my students - I think, the NEOS Server is a good fundament for "Computer Based Training".
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Education: O.R. & Econ. |
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In my microeconomics principles class, I spend some time on cost
minimization problems. Solutions to these problems are nicely illustrated by Neos. My students and I all appreciate having Neos
available to us.
I have used NEOS Server in various courses at University of Missouri --Rolla
and Bilkent University and encouraged graduate students to supplement their
computational work in their thesis research with various resources provided
by NEOS.
During the coming Spring semester, I will be asking students to use NEOS Server in the following two courses:
In addition, I find NEOS Server an excellent example of an Internet tool in decision sciences.
I teach "Modeling and Optimization" in
University of Valencia (SPAIN). During the academic course, we use a GAMS
software to model and solve business problems. When the number of
variables exceeds the student version (50 binary or integer variables), we
use the NEOS Server to solve and analyze the result of our models.
I think is very interesting the possibility to use this Internet service. In my opinion this service must be continued.
I am using neos as a tool for my OR course.
The hw is to use MINLP for mixed integer programming
problems. All submissions last week are from my students!
NEOS is a very good tool for my teaching.
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Education: Engineering |
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I teach a sophomore-junior class required of all civil engineers. The
title is Design and Planning of Civil Engineering Systems, and the topic is
optimization as an approach to design. The course is heavy on linear
programming, with some non-linear optimization as well. We use two
optimization engines: that contained in Excel, and Neos. Our students
have found Neos to be quite useful.
We are planning to test a number of problems related to Chemical
Engineering Process design and synthesis (which are optimisation problems)
for a postgraduate level course. The testing is with a view to incorporate
the facilities of the server for the students.
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Business & Finance |
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I am trying to fit a nonlinear model that estimates "Value at Risk"
of mexican financial institutions based on their assets, liabilities
and mean duration of both.
We are using the NEOS server for making an optimal duty-schedule for
employees involved in ground-handling activities in a Airport environment.
For investigating the feasibility of optimization techniques we find the
NEOS services very useful.
We are using the NEOS Server for verifying an algorithm designed for
solving a special 0-1 ILP problem. You can find our 0-1 ILP Model
in the following reference:
F Ghasemzadeh, N Archer and P Iyogun; A zero-one model for project portfolio selection and scheduling, Journal of Operations Research Society(1999) 50, 745-755
The application is a DSS based on this model.You can find more info in two last sections of the following paper and reference 3 of it.
I have modeled a seat assignment problem into the min-cost flow problem
and submitted data to the NEOS solver.
Cisco Systems
We have been doing research on System Identification techniques via an NLP
based maximum entropy formulation. We use system i/o data to determine the
underlying parameters for the following LTI system:
x(t+1) = Ax(t) + Bu(t)
y(t) = Cx(t)
In our case, the u's represent new customers for telecommunications
services. The y's represent their observed state. We seek to determine
A,B,C, and x to forecast future purchasing behavior from knowledge of u and
y.
The NLP formulation was one of 4 techniques we examined. We found that the formulation did not work too well for our problem. The main reason was that some of the matrix parameters must be quite small, making the problem difficult for most solvers. The equality constraints also caused problems in finding a feasible solution. We found that only LOQO would provide successful runs. Also, the predictive capability of the solution turned out to be not as good as some other techniques we examined. This result is probably application specific. I suspect applications with less extreme requirements for parameter values might work quite well.
We are using the NEOS server for testing our NLP formulations for generating
financial scenarios and for testing the performances of different NLP
solvers.
I use this site to run optimizations of selections
of prospects to solicit for refinancing mortgage loans.
I typically mail 770,000 - 800,000 offers per week from a weekly available to mail universe of 1.7MM-2.0MM consumers. I seek to maximize the expected revenue from the mail stream by combining response rate and revenue generated.
I am self taught in AMPL and quickly outgrew the student's version which came with Fourer's terrific book. I really appreciate having the horsepower available to run my optimizations. I now complete in 5-10 seconds what took one of my subordinates 3-4 days each week to do manually.
Keep up the good work and PLEASE PLEASE keep this site
open to the public.
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Science & Industry |
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I wish to extend my regards to your extraordinary work. I have just gone through the text associated with the site and I found it very interesting and so much related to my work. I should have told you that I'm an electrical power engineer involved in the optimization of medium and high voltage power systems. I build mathematical models with either technical, economical, or hybrid objectives and use numerical optimization algorithms to find the optimal design parameters of power systems.
NEOS is really cool!
I am a die-hard GAMS user and would like to see GAMS interfaces
to NLP and MINLP solvers, as my interest is primarily in solving
nonlinear chemical engineering problems (production planning,
scheduling, etc.)
Keep up the good work!
Just discovered your great site. I have a problem arising in biophysics
in which I need to find the center of a polytope generated by an LP
problem (or equivalently all the vertices).
I am studying the quantum mechanical
tunneling probability in a two component Bose-Einstein condensates. I
use the Lancelot solver and AMPL code.
I have used NEOS as an excellent guide to optimisation methods and locating
associated software. Its the best resource I know of on the web and has been
very useful in the development of optimisation methods in our process
modeling software. Therefore, I welcome any developments to improve the
site.
AspenTech Ltd
We believe the NEOS optimization server provides a very
valuable service.
ABAQUS/Design Development Manager
Hibbitt, Karlsson & Sorensen, Inc.
We are using the NEOS Server for solving linear and nonlinear
complementarity problems
in engineering mechanics and in robotics (till now, mainly unilateral
contact problems
and friction).
The problem we are considering is the design of a yagi antenna. These antennas
consist of an array of wires and are frequently used as TV antennas. In the 1960s a
lot of research has been done on the best design of this type of antenna. However,
all research was experimental and therefore very costly and time consuming. Our idea
is trying to design antennas by using the computer as a tuning device, i.e. starting
from an initial design to have the computer finding the optimal solution by using
constrained optimization methods. If this approach works, it could be used for the
design of the future Square Kilometer Phased Array (SKA) for radio astronomy to look
back in time to the first moments of the universe, which is to be build in about 10
years from now.
We have tried various solvers on NEOS to see if this is possible at all and the yagi antenna has been used as a test case for which good validation is possible. The NEOS server offers a lot flexibility and various (well-known) solvers. It gives us the opportunity to find out which approach works best. Without this server it would probably be impossible to find out what strategy is most likely to succeed. Preliminary results are very encouraging for this approach.
I would like to express my support for this service. I am using this
server to solve a non-linear optimization problem to determine the
resource requirements for broadband networks using effective and
decoupling bandwidths. The objective function in my optimization is
assumed to be linear. The constraints are non-linear, exponential and
sometimes conditional.
The NEOS server helped me tremendously, since my background in optimization is weak. I was nevertheless able to further my research using this service
I just used AMPL-MINOS to solve an LP
arising from a stochastic programming application
that Jeff and I are looking at. The debug-resubmit
process could not have been simpler nor more convenient.
Fine stuff.
Here at our group at the Philips Research Laboratories we have used the
NEOS Server in our search for nonlinear optimization methods for circuit
simulation purposes.
I just found NEOS while looking around for a solution to my problem
(forgive the pun) attempting to optimize a couple of functions for a
computer game I am designing. It's very helpful, thank you
I am using the NEOS Server to solve optimization problems that arise in
(1) distance geometry and multidimensional scaling; and (2) design of
experiments.
We have used the NEOS server to solve NLP problems we formulated from
Integrated Circuits Computer Aided Design. And we plan to use it again
in the near future.
I have been using your AMPL front end and solvers to develop an
assignment problem.
BTW, this is a great service; allows me to develop without incurring
client costs or requesting software my university cannot afford.
I used your codes (Minpack) in the past. Any deployment of
nonlinear methods on a server are beneficial and their importance
will increase.
Thank you for your help. NEOS is very useful to me : I am solving huge
multi-commodity flow problems written in AMPL, and we do not have AMPL
available here. I have been using NEOS for solving multi-commodity flow problems arising
in the optimization of weights for routing in the Internet.
Congratulations for this nice tool and your continuous efforts to improve it.
I did send problems to the PCx and the BPMPD solver and
was very pleased with the outcome. These were rather small problems
in the field of chip design. Larger problems consumed too much
computer memory, let alone the time a solution might have taken.
Nevertheless, information is well categorized, easily available and very supportive, as well as the people involved are. I had misunderstood the right-hand-side labels of the MPS-format. Not realizing that they supported different versions, I thought each RHS had a different label. I reported the resulting output as not good and by the time I noticed my mistake, one of you pointed it out to me as well. Good luck with your efforts in making the NEOS server even better.
I have used some NLP solver from NEOS to solve a circuit optimization
problem. It's very helpful to use it this way, other than installing
those packages by myself.
By way of introduction let me mention that as a sideline to my professorial
duties, I maintain a website which seeks to direct people to appropriate
parts of mathematics; my intended audience is students and professionals who
have at least a couple of years exposure to college level mathematics.
Turn to http://www.math-atlas.org/welcome.html and you'll see a set of blobs on the screen; there's also one on each index page e.g. http://www.math-atlas.org/index/15-XX.html . The positions of these blobs were determined by the NEOS server. I was happy to have access to the server because I think having the blobs positioned appropriately helps understand the topic, and therefore adds to the quality of the web pages.
What these blobs are is sets of papers published in mathematics (specifically, papers reviewed in Mathematical Reviews 1980-1999). Each paper in MR is assigned one or more classification codes from a subject classification system of mathematics. I used the incidence data showing how many papers published in various subdisciplines were given secondary classifications in other subdisciplines; these data gave a sort of metric on the subject areas, which indicates that say Group Theory is close to Ring Theory but far from Differential Equations. So conceptually I then have the various disciplines arrayed in some high-dimensional space, some pairs of them closer to each other than other pairs. In my mind I visualize the subjects hovering around like stars in the Milky Way galaxy.
Well, there are standard tools for projecting such a picture to a plane so as to show the distance relationships optimally -- that is, you can sort of figure out the "main plane" of the galaxy. The problem is that when you project the various blobs to the plane of the galaxy, some of them will obscure others which are directly above or below them.
So here's where I used NEOS: I took the nominal positions of the different blobs and asked for the minimal amount of jiggle I would need to separate them on the plane. It's not a hard project, conceptually, and I imagine cartographers have packaged routines to deal with this. But certainly there were too many variables and constraints to allow an analytic solution (and way too much computation to appeal to a theoretician like me). It took me a little while to master the NEOS syntax (e.g. I had to remember to tell it to display the answer...) but once I got it down to a science I was able to have the server supply the results I wanted in a painless way.
There's quite a bit of arbitrariness in the way the data are massaged to
produce a picture: one shouldn't try to read too much into these images.
On the other hand, when left to their own devices, the programs tended to
draw pictures which corroborated what I would have drawn on my own (when I
had some prior knowledge of a subdiscipline) and gave hints about what
real connections existed in subdisciplines with which I was not familiar.
So I'm quite happy with the results so far.