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PostPosted: Wed Sep 12, 2018 3:40 pm 
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Joined: Tue Sep 11, 2018 9:29 pm
Posts: 4
Hello,

I am having some problems with TCP tagging. I am running the AS on one machine and the client on another machine. Data transfers fine. But, when I run the P300 speller example, i get the following error: Unable to connect to AS's TCP Tagging plugin, stimuli wont be forwarded.

I've seen this error discussed on some previous posts, but those seemed to be in regard to playing back recorded data. I have tried to disable the windows firewalls on both machines, and that didn't work. The IP address is correct in the AS box, but I am not sure if I need to change this somewhere else. Also, I don't see anywhere on the client side where I can check the TCP port.

Finally, I tried running the AS and client on the same machine, and there was no problem in this regard.

Thanks,
James


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PostPosted: Thu Sep 13, 2018 7:33 am 
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Joined: Tue Dec 04, 2012 3:53 pm
Posts: 751
Location: INRIA Rennes, FRANCE
Hello James, this is a limitation on the client side: openvibe doesn't expose the necessary setting to the user. This can be changed by modifying the code, but there is a potential problem: the network latency is not taken into account by the approach. How about the following: I build you a custom version exposing the setting, and you give it a try and report back to the forum about your experience?

If both computers are on the same local network and there's little transmission delay or packet jitter, it just might work. But I haven't tested.


Cheers,
Jussi


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PostPosted: Thu Sep 13, 2018 10:38 pm 
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Hi Jussi,

Glad to know it wasn't me!

I'd be happy to do a comparison between single computer vs. networked tagging. Given that there wouldn't be any clear indication of actual time of the stimulus, my guess is that the best I could do would be looking at the comparisons between the p300 accuracy when networked vs. on a single computer.

Actually, I've just started working with the Mobita, and I think it has a channel for a photodiode too, so that might actually give us a clear indicator of differences due to network delay.

Best,
~James


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PostPosted: Fri Sep 14, 2018 11:32 am 
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Joined: Tue Dec 04, 2012 3:53 pm
Posts: 751
Location: INRIA Rennes, FRANCE
Hello again,

I made you a custom version of the 'P300 visualizer' box so that the TCP Tagging address can be specified for it. To use this, extract the attached archive so that the .dll in it replaces the existing one of the OV 2.1.0 installation (you can backup the existing .dll elsewhere if you like). Then, find openvibe.conf file (under share/) and add the following to it

Code:
TCPTagging_Server_Hostname = name or ip
TCPTagging_Server_Port = number


This mod only changes the P300 Visualizer box. That should be sufficient to carry out a P300 experiment.

The presence of the new .dll should be seen in a way that if the name/port cannot be connected to when pressing play on a scenario with a P300 Visualizer in it, the name/port will be included in the printout to the console. The old version doesn't print them.

I'm very interested to hear how it behaves over the network vs on the same computer.

Cheers,
Jussi


Attachments:
openvibe-plugins-simple-visualisation-tcptagging.zip [111.33 KiB]
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PostPosted: Tue Sep 18, 2018 10:06 pm 
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Joined: Tue Sep 11, 2018 9:29 pm
Posts: 4
I've been trying to get the original code to work with AS and presentation on the same computer. I've been getting an error when I try to run the online speller. Perhaps the relevant portion is where it says it is attempting to perform arithmetic on field '?'

Any suggestions?

Thanks,
~James

[ WARNING ] Please report to box author and attach your scenario
[ WARNING ] At time 28.242 sec <Box algorithm::(0x0000445b, 0x000068e3) aka P300 accumulator> Lua error: ...i-examples/p300-speller/p300-speller-accumulator.lua:150: attempt to perform arithmetic on field '?' (a nil value)
[ INF ] At time 28.242 sec <Box algorithm::(0x0000445b, 0x000068e3) aka P300 accumulator> Lua script terminated
[ ERROR ] {Error description} : {Box algorithm <P300 accumulator> processInput function failed}, {Error type} : {ErrorType::Internal (code 2)}, {Error location} : {C:\ovm\sdk\kernel\src\kernel\player\ovkCSimulatedBox.cpp::231}
[ ERROR ] {Error description} : {Process failed for box with id (0x0000445b, 0x000068e3)}, {Error type} : {ErrorType::Internal (code 2)}, {Error location} : {C:\ovm\sdk\kernel\src\kernel\player\ovkCScheduler.cpp::670}
[ ERROR ] Scheduler loop failed.


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PostPosted: Wed Sep 19, 2018 7:46 am 
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Joined: Tue Dec 04, 2012 3:53 pm
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Location: INRIA Rennes, FRANCE
Hi,

you can open the lua script in text editor to see what it does. ;) In particular, it'll need exactly the kind of stimulation stream as input that would result from the operation of the original scenarios including the p300 stimulator box (instead of presentation). You can use the stimulation listener box to investigate the timeline coming from the 'real' acquisition server and then compare how your timeline is different. You can also enable the do_debug variable in the lua script. I imagine your timeline is somehow different than what the lua script expects and as a result the 'state machine' is not expecting to end on a line 150 at that point (its likely missing something it should have received by then).

Do the scenario work when your run it out of the box as we provide it, without Presentation mods etc?


Cheers,
Jussi


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PostPosted: Wed Sep 19, 2018 5:53 pm 
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Hi Jussi,

The error was with the "out of the box" basic online p300 speller. The initial acquisition and train classifier scenarios worked fine, but the online one isn't.

Best,
~James


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PostPosted: Fri Sep 21, 2018 8:58 am 
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Joined: Tue Dec 04, 2012 3:53 pm
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Location: INRIA Rennes, FRANCE
I can't reproduce the issue, the scenarios seem to work for me. If you want it fixed, please post exact step-by-step instructions how to reproduce along with list of any modifications you've made to the scenarios.


Best,
Jussi


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