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- Path: sparky!uunet!mcsun!sunic!chalmers.se!dtek.chalmers.se!d8linha
- From: d8linha@dtek.chalmers.se (Haakan Lindh)
- Newsgroups: comp.ai.neural-nets
- Subject: Training Data to Aluminium Appl.
- Message-ID: <12958@chalmers.se>
- Date: 26 Jul 92 21:21:21 GMT
- Sender: news@chalmers.se
- Organization: Chalmers University of Technology
- Lines: 56
-
- Hi,
- My friend and I are currently doing our thesis project for an Aluminium
- Smelter Factory in Sweden. The task is to control the owen temperature
- better than they are doing at the moment. We've got complete access to
- their process database and they've explained some basics about the process.
- There is, for instance, a well-known connection between the amount of added
- Aluminum Flouride, AlF3 (a chemical they add once every day), and the
- temperature in the owen some time period later. Then we have all the noice
- (as usual).
- Our only control parameter is the amount AlF3 added each day, so the task is
- to predict how much to add to receive some predefined temperature the following
- day.
- We're running Stuttgarts Neural Network Simulator (SNNS) under UNIX on a
- SPARCstation.
-
- The net contains (right now) 10 inputs and then 4 binary coded output
- units (0-16). We have approx. 400 connections in the net.
- We are currently trying to predict the temperature for tomorrow using super-
- vised learning. It is sufficient if the predicted temperature lies within some
- specified boundaries, i.e no demand of absolute correct prediction.
-
- Our first question is about the process data:
-
- The process data contains a lot of data close to the temperature average and
- less and less data the futher you get from the average (like a normal
- distributed curve). Should we remove some of the data near the average in
- order to get a more even `spread' in the training set or should we just train
- the net with the whole set as it is?
-
- The 2nd and 3rd quiz is regarding the training data:
-
- According to a prof. in Information Theory, we should uncorrelate all data
- by using the Gramm-Schmidt method. Is it common praxis to do that?
-
- The database contains over 25,000 records. Should we try to train the net with
- as much data as possible or is a small subset sufficient?
-
- 4th:
-
- We've reached quite satisfactory results by only using temperature and
- the amount of added AlF3 five days back as input parameters. We took process
- data for some months back which gave us approx. 1000 training data.
- The net reached a pretty satisfactory level after only 200 training cycles.
- The temperature depends on other parameters as well, but their influence is
- not as great as AlF3. Should we add them as well to get even better results
- and, in that case, should we add as many as we can or is it better to add
- only a few to keep the net as small as possible?
-
- We would really appreciate any response to the question above and especially
- if someone knows about any similar project (ongoing or completed).
-
-
- --
- d8linha@dtek.chalmers.se
- Chalmers Univerity of Technology, Sweden
- Department of Computer Science and Engineering
-