October 28, 1998
QuestChat with Roxana Greenman
NASA Ames Research Center, Moffett Field, CA
- 3 - 08:48:52 ]
Hello to our early arriving Aerospace Team Online chat participants! Aerospace
Team Online chat with Roxana Greenman from NASA Ames Research Center will
begin at 9:00 a.m., Pacific Time. Be sure you have read Roxana's autobiography
before joining this chat.
- 4 - 08:49:25 ]
Once the chat begins, Roxana will attempt to answer as many of your questions
as she can, but please be patient. The chat will "moderated" if Roxana
gets behind in answering your questions. This means that only a few questions
will be posted to the chat room at a time. Don't worry if your questions
do not appear on your screen immediately. They will be posted as Roxana
answers those ahead of you.
- 5 - 08:49:47 ]
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- 6 - 08:50:16 ]
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- 8 - 08:58:16 ]
RE: [Ann/AERO-Ann/AERO] Good morning aspiring
and practicing research scientists and Aloha.
Welcome, Ann. We'll begin our chat shortly. Please stay with us!
- 9 - 08:59:24 ]
Hello and welcome to today's Aerospace Team Online chat with Roxana Greenman
from NASA Ames Research Center! Roxana researches the field of computational
fluid dynamics (CFD). CFD is the process of using computers to solve complex
equations associated with aircraft flight. One of her current research
areas is the development of new methods that incorporate information technology
into CFD design methods. She is trying to learn the benefits of combining
technology based on our biological nervous systems with special computer
- 10 - 08:59:44 ]
And now, here is Roxana Greenman to answer your questions.
- 14 - 09:08:01 ]
Good Morning! I look forward to answering and chatting with all of today!
- 13 - 09:06:46 ]
RE: [Ann/AERO-Ann/AERO] Would you please describe
the high-lift devices which you design and explain how they relate to
the human nervous system.
Good Morning Ann! High-lift devices are located on the wing. They consist
usually of a slat which is the leading-edge device and a flap which is
the trailing-edge device. One of there many purpose is to help the aircraft
generate more lift. They are used at takeoff and landing and are stowed
during cruise. Now, neural networks are computational devices that model
the human nervous system. They are two different items. High-lift devices
do NOT model the human nervous system.
- 18 - 09:15:23 ]
Roxana, perhaps you can share with us any obstacles or constraints you've
had to contedn with as you've moved along in your career.
- 20 - 09:18:30 ]
I recently received my doctorate at Stanford University. Researching,
writing, and defending my Ph. D. dissertation has been one of the most
difficult events that I have accomplished. But at the same time, it was
one of the most rewarding!
- 22 - 09:20:54 ]
Recently, I have integrated a genetic algorithm, neural network, and an
optimizer together to find the maximum lift of a multi-element wing. The
wing had a slat, main, and flap element on it. The genetic algorithm mimics
the evolution process of the "survival of the fittest" to find the best
- 24 - 09:23:55 ]
RE: [Shae-Shae/LamarUniversity] You said that
working with NASA has alwaays been fun. What kinds of things do you do
that make this possible?
Good Morning Shae! I enjoy working at NASA because there are so many opportunities
that are available to me. I was able to choose the topic of research that
I have been involved in for the last 3 years. This is important to me.
Also at NASA, my collegues give me great support and help to succeed.
It also rewarding to be working with scientists who are known world-wide
and I also enjoy working with all the state-of-the-art equipment.
- 26 - 09:26:13 ]
RE: [Ann/AERO-Ann/AERO] Yes that would be great,
also could you refer us to any published info on your research and/or
available space science publications. Thank you.
Ann, in my Ph.D. dissertation, I have an excellant Reference list. Here
is the reference for my dissertation: Greenman, R. M., "Two-Dimensional
High-Lift Aerodynamic Optimization Using Neural Networks, Ph. D. Dissertation,
Stanford University (see Also NASA TM 1998-112233), June 1998. If you
need more please let me know.
- 28 - 09:29:21 ]
RE: [Shae-Shae/LamarUniversity] I wish to have
a career in NASA and so, would love to have an inside view on the kinds
of things that are done and the opportunities that will be presented.
First of all, I would highly encourage getting involved with NASA as you
are now! This is what I am currently working on: 1) Preparing journal
articles 2) Investigating genetic algorithms and other information technology
3) I will participate in the planning of IVHM (Integrated Vehicle health
monitoring) 4) I also review proposals and other papers 5) business stuff.
But remember that there are many different opportunities with NASA. It
really depends on your job and what research group you are in.
- 29 - 09:31:47 ]
RE: [Shae-Shae/LamarUniversity] Do you work
with any of the space program? That is the area in which NASA has drawn
my attention most.
Currently, I am not involved with the space program. But in the NEAR future
I will be. With IVHM we will be looking at space vehicles and my divion
is also moving in the direction of space. We will be examining Reuseable
Launch Vehicles (RLV). I am very excited about this!!
- 31 - 09:35:02 ]
RE: [Ann/AERO-Ann/AERO] Roxana, I am an adult
educator, un-fortunately the school day has not begun yet here (the students
are just getting on the bus). Your explanations of complicated research
are so clear and easy to understand. On a recent Discovery channel show,
it was suggested that space travel and travel to the deep sea are similar.
Since you're the ocean is important in your leisure hours, have you observed
I have also heard about space travel and travel in the deep sea are similar.
Unfortunately, I have not done either. So I am not sure.
- 32 - 09:35:52 ]
As a reminder, at the conclusion of today's chat, please let us know what
you thought about it at http://quest.arc.nasa.gov/qchats/qchat-surveys.
- 33 - 09:36:09 ]
RE: [Shae-Shae/LamarUniversity] That sounds
Thanks!! Shae -- what do you study? Aeronautics? Do you like your University?
- 35 - 09:39:54 ]
RE: [Shae-Shae/LamarUniversity] If so, what
kinds of things do you do?
I imagine in the future, I will apply computational fluid dynamics (CFD)
to the different space vehicles that we will be researching. Also, I will
use CFD with information technology such as neural networks, genetic algorithms,
and others to try to locate optimums or to enhance our database.
- 37 - 09:43:58 ]
RE: [Shae-Shae/LamarUniversity] I am studying
to become an Aerospace engineer. I am not really sure yet about what in
particular I would like to do and am presently searching for information.
Good for you! It sounds like you are definitely intesteted in space versus
aeronautics. You must be excited about the next launch in the next day
or so. Another great source for information on different areas of research
are the journals. For example, Journal of Aircraft, AIAA Journal, and
Journal of Fluids Engineering. These will have a lot of information on
the new topics that are being researched. Sometimes just reading the abstracts
will give you a good feel for what is important in industry and govenment.
- 40 - 09:49:20 ]
RE: [Shae-Shae/LamarUniversity] RLV sounds
interesting. In what particular ways would you apply CFD to this progect?
CFD can be used in RLV research in many ways. One imporant result from
CFD would be the loads that the vehicle would experience during its flight
and especially in re-entery. In this case, we will have to incorporate
chemistry with the Navier-Stokes equation (conservation of mass, momentum,
and energy) due to the high heating. Neural Networks can then be used
to minimize the amount of data points needed to be computed. The neural
networks can fill in the design space once it is trained properly with
some inputs and outputs.
- 43 - 09:51:10 ]
RE: [Shae-Shae/LamarUniversity] How do I gain
access to such journals?
Most of these Journals are on the web -- or at least the titles of the
papers and the abstracts. Do a search for AIAA and ASME and go to their
home pages. Then just have "fun". Also, you can find all these journals
in a good technical library.
- 45 - 09:54:30 ]
I'm in a algebra class. I'm interested in knowing what math classes would
i need to take to be in your feild?
You do need a lot of math to be an Aerospace engineer. In high school,
I took algebra, geometry, trig, and calculus. But then in college I re-took
Calculus. I basically took math all through my bachelors and Ph. D. Some
other course I took in college are differential equations, simlitude,
advanced applied math. But they were all fun and interesting. Just make
sure you take them in the correct order because they are usually pre-requisites.
- 46 - 09:56:08 ]
RE: [Shae-Shae/LamarUniversity] Oh, so one
of the most important things you would do has to do with the intelegence
of the craft?
Yes, the control system of the aircraft is very important. There are stability
and control engineers who work on just that!
- 48 - 09:56:59 ]
RE: [Shae-Shae/LamarUniversity] Are they readily
availible to everyone?
Yes, you should have no problem locating the Journals, if you do, please
let us know.
- 50 - 10:01:09 ]
RE: [Shae-Shae/LamarUniversity] Would you please
expand upon the neural network you spoke of earlier?
Neural networks (NN) are computational devices that are very good at predicting
non-linear data once they are trained on a data set. The neural networks
are trained by presenting input-output pairs to the networks. Then the
NN adjust the connectivity weights between nodes until the error between
the predicted value and the actual value of the output for a given input
in minimized. Thus, they are used to fill in a design space that is sparse.
They were designed to simulate the human nervous system.
- 51 - 10:01:59 ]
EVERYONE, Roxana will be able to stay online with us for another 15-20
minutes today. For those of you leaving us, please let us know what you
thought of today's chat at http://quest.arc.nasa.gov/qchats/qchat-surveys.
- 52 - 10:02:20 ]
RE: [Shae-Shae/LamarUniversity] This network
sound very interesting.
The NN are very interesting and it is amazing at how well they perform!
- 54 - 10:04:06 ]
RE: [Shae-Shae/LamarUniversity] I thank you
very much, Dr. Greenman, for your time and gift of information. I regret
that I must go now.
Thank you for participating! I enjoyed it, it was my pleasure. I wish
you the very best in your future career!
- 57 - 10:09:06 ]
This concludes our chat with Roxana Greenman from NASA Ames Research Center.
Thank you to everyone for joining us today!
- 59 - 10:09:33 ]
A special thanks to Roxana for sharing her time and expertise with us
- 60 - 10:10:46 ]
Please let us know what you thought of today's chat by using our online
feedback surveys at http://quest.arc.nasa.gov/qchats/qchat-surveys.
- 61 - 10:11:17 ]
RE: [Ann/AERO-Ann/AERO] I'd like to thank you
too. would you care to comment on this week's historic space launches?
Thank You too Ann! It was my pleasure. Thank you for your questions. I
think it is just remarkable that Senator Glenn is going up again! He is
a great hero to all of us as well as the other astronauts.
- 62 - 10:11:46 ]
To learn about upcoming chats with ADTO experts, check the ADTO chat page
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- 63 - 10:13:04 ]
Once again, we would like to than everyone and Roxana for joining us for
today's chat. Please join us on Wednesday, November 4 at 4:00 p.m. Pacific
Time for our next ADTO chat with Susanne Ashby from NASA Ames Research