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. next contribution


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Education

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next contribution 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.


next contributionI 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.

next contributionI 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.

next contribution I am using NEOS for solving problems and examples for the classes I teach.
Faculdade de Ciencias da Universidade de Lisboa, DEIO

next contribution 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.

next contributionWe 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.

next contribution 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.

next contributionThank 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.

next contributionI used NEOS for a project in a grad-level cs class at Purdue Univ this past fall, on a network flow problem.

next contributionI 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.

next contributionWe 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.

next contributionThe 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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next contribution 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!

next contributionWe 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!

next contributionWe used the NEOS server for linear programming class at the University of Wisconsin-Milwaukee.

next contributionI 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.

next contributionWe are using the NEOS Server in a class on linear and nonlinear programming at Ohio University.

next contribution 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.

next contributionI 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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next contributionIn 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.

next contributionI 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.

next contributionI 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.

next contributionI 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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next contributionI 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.

next contributionWe 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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next contributionI 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.

next contributionWe 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.

next contribution 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.

next contribution I have modeled a seat assignment problem into the min-cost flow problem and submitted data to the NEOS solver.

Cisco Systems

next contributionWe 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.

next contributionWe are using the NEOS server for testing our NLP formulations for generating financial scenarios and for testing the performances of different NLP solvers.

next contributionI 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. next contribution


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Science & Industry

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next contribution 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.

next contributionNEOS 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!

next contributionJust 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).

next contributionI am studying the quantum mechanical tunneling probability in a two component Bose-Einstein condensates. I use the Lancelot solver and AMPL code.

next contributionI 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

next contributionWe believe the NEOS optimization server provides a very valuable service.

ABAQUS/Design Development Manager
Hibbitt, Karlsson & Sorensen, Inc.

next contributionWe 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).

next contributionThe 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.

next contributionI 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

next contribution 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.

next contributionHere 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.

next contributionI 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

next contributionI am using the NEOS Server to solve optimization problems that arise in (1) distance geometry and multidimensional scaling; and (2) design of experiments.

next contributionWe 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.

next contributionI 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.

next contribution I used your codes (Minpack) in the past. Any deployment of nonlinear methods on a server are beneficial and their importance will increase.

next contributionThank 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.

next contribution 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.

next contributionI 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.

next contributionBy 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. next contribution

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