21) Forums : Technical Support : Tasks will not complete (Message 11410)
Posted 13 Jul 2012 by Profile Benjamin Wandelt
Post:
The code controling the progress bar is on the least tested parts of our BOINC instrumentation, so it is quite posaible for that to have a bug which makes progress appear to jump backwards at various points (essentially right after checkpoints). This may explain some of this behavior.
Also, some work units compute cosmology in open or closed universes which makes them take a lot longer than the ones where the universe is exactly flat. To simplify allocation of credit we decided to award a constant amount of credit for all work packages. This credit amount is somewhat high on purpose to make up for these special work units.

Thank you for highlighting this problem again. We will look at it in our pending update to the new kernel.

Best regards,
Ben
22) Forums : Technical Support : Problems running project!! (Message 11189)
Posted 2 Jun 2012 by Profile Benjamin Wandelt
Post:
Hi Peter -

Welcome to Cosmology@Home!

The work units do take a long time to complete. There are occasionally download errors and uploading sometimes takes several attempts.

In spite of this, the code recovers from this, eventually finds a work unit to download and does work.

We will continue to hunt for these bugs until we've found them but for now we hope that you can be patient with us!

Best,
Ben

23) Forums : Technical Support : URGENT PROBLEMS THREAD (2009 and after) (Message 11039)
Posted 7 May 2012 by Profile Benjamin Wandelt
Post:
Any news on this? Did the download errors become less frequent or---dare I say it---disappear?

Best,
Ben
24) Forums : General Topics : Error while editing User-Profile (Message 11026)
Posted 5 May 2012 by Profile Benjamin Wandelt
Post:
Yes we finally fixed it - please see this message on the announcement message board. Please help spread the good news.

Best,
Ben
25) Forums : Technical Support : URGENT PROBLEMS THREAD (2009 and after) (Message 10861)
Posted 22 Apr 2012 by Profile Benjamin Wandelt
Post:
Hi -

I made the modification to the config.xml file and restarted the server. Please let me know if you see any improvement. If yes, I'll make a news post on the front page.

Thanks,
Ben
26) Forums : Cosmology and Astronomy : Featured Concept: Dark Matter (Message 10859)
Posted 22 Apr 2012 by Profile Benjamin Wandelt
Post:
Hi -

I am personally pretty agnostic about the nature of dark matter, meaning that I am not invested in any one particular model. I do think we need it. I also think that these are exciting times where a number of (disputed) hints are being confronted with an accelerated schedule of experimental and observational searches. Those look for direct detection of dark matter particles in (underground) labs, production of DM particles in particle accelerators (such as the LHC), as well as indirect evidence for dark matter from annihilations or decays (gamma rays, synchrotron radiation) that cannot be explained as coming from ordinary astrophysical origins.

Remember that we need dark matter for its gravitational effects, but all of these approaches are looking to get information about dark matter through its non-gravitational interactions, either directly or indirectly.

At the same time we are trying to resolve several puzzling questions about dark matter:
- what are the effects of the physical properties of dark matter on its spatial distribution, e.g. the density profile of dark matter clumps and the abundance of subclumps within larger clumps;
- what is the relationship between the distribution of dark matter and visible matter; and
- does dark matter have a (small but in some way noticeable) interaction with ordinary matter?

On that last question a recent conversation reminded me that 10 years on, my collaborators and I still hold the record for the most limiting constraint on baryon-dark matter interactions (Cyburt et al. 2002), at least in some energy ranges.

Nearly every month there is a paper claiming evidence for (or against as in this case) dark matter. This is truly one of the great questions of our time and what makes it even more exciting is that it has a real chance of being resolved in the near future. But I won't be more specific than that!

All the best,
Ben
27) Forums : Cosmology and Astronomy : Featured Concept: Dark Matter (Message 10844)
Posted 21 Apr 2012 by Profile Benjamin Wandelt
Post:
Hi

Not at all a bad idea - in fact this is one of the proposed theories for dark matter, called the Dvalie Tye model proposed in 1998.

There is another idea that is similar in some ways called mirror dark matter. In this version another Universe is not necessarily involved. Here is the idea: if there are in fact not one but two copies of the standard model and particles in each are not allowed to interact with those of the other, then there could be a whole dark world out there, right in our universe, with dark stars, dark gaalaxies, dark people (?) and we would only know about it through its gravitational effects.

Note that our ordinary matter, including us, would be the dark matter to the other side. This symmetry is what led to the name mirror dark matter.

If that dark standard model were exactly like the one we know and love, then the Mirror Dark Matter model makes some interesting predictions, since dark matter would not be dissipationless in that model (it would be like ordinary matter interacting with the dark counterpart of the photon etc, so it could cool and condense into stars etc). These predictions lead to the model being disfavored observationally since the profiles of dark matter halos required to explain rotation curves seem to need to be much more extended than the ordinary matter.

But that's the way it should be for a real scientific theory: it should have falsifiable predictions! There is nothing as unsatisfying as a model or a paradigm that can shift and change to agree with whatever the observations come out to be...

In any case, congratulations - you had a serious scientific idea and there have been a number of papers and studies working out observational constraints on it!

All the best,

Ben
28) Forums : Technical Support : URGENT PROBLEMS THREAD (2009 and after) (Message 10835)
Posted 20 Apr 2012 by Profile Benjamin Wandelt
Post:
Thank you for looking into this and posting - I hope this fixes it for the user.

Best,
Ben
29) Forums : Cosmology and Astronomy : Featured Concept: Dark Matter (Message 10834)
Posted 20 Apr 2012 by Profile Benjamin Wandelt
Post:
Speaking of dark matter: almost on the same day we posted dark matter as the featured concept on C@H, ESO (the European Southern Observatory) came out with this hot news flash. Check out the

ESO press release

This would be pretty amazing if true. I have spent a couple of hours digging through the associated paper (which is linked from the press release) and while they seem to have done a thorough analysis, they also assumed quite a lot of information about the matter distribution in the galaxy.

Note also that their statement of "no dark matter in the solar neighbourhood" is incorrect. I am amazed that they chose to phrase it this way, since there are passages in the paper that show they know better.

Here is the point: their observational technique is not sensitive to a very smooth distribution of dark matter throughout the volume they probe. So they have no constraint on the overall amount of dark matter, just on gradients in the distribution. It is true that standard models of the dark matter distribution in galaxies involve an amount of dark matter that changes with distance from the galactic center, so it is true that they can constrain the standard dark matter models.

But the smallness of the constraint is very surprising and should be looked at by other groups.

Exciting times!

Best,
Ben


30) Forums : Cosmology and Astronomy : Featured Concept: Dark Matter (Message 10809)
Posted 17 Apr 2012 by Profile Benjamin Wandelt
Post:
Hi -

I hope you enjoyed our new featured concept on Dark Matter. Feel free to post your questions and comments here!

All the best,
Ben
31) Forums : Technical Support : URGENT PROBLEMS THREAD (2009 and after) (Message 10760)
Posted 15 Apr 2012 by Profile Benjamin Wandelt
Post:
Hi Mary -

You are doing useful work, just keep crunching. Our system is built to be robust so even when there are work packages you do not complete, or if there are download errors, it's fine for us. Your machine will eventually download and return useful work and that is what keeps this project going.

All the best,
Ben
32) Forums : General Topics : Does the app checkpoint? (Message 10748)
Posted 14 Apr 2012 by Profile Benjamin Wandelt
Post:
Yes, that's correct. The app checkpoints but not very often and there is some overhead to restarting from a checkpoint.

Best,
Ben
33) Forums : Technical Support : Can't Seem to Modify Preferences (Message 10692)
Posted 10 Apr 2012 by Profile Benjamin Wandelt
Post:
Hi again,

Another attempt to fix this. The problem eems to have been caused by a faulty BIONC update script. A manual fix was applied. I hope this will do it.

Best,
Ben
34) Forums : General Topics : Why do you participate in Cosmology@Home? Who is the \"most surprising\" participant? (Message 10691)
Posted 10 Apr 2012 by Profile Benjamin Wandelt
Post:
Dear all

Thank you so much for your posts. After a busy day I took some time to read through them again. I am moved by your stories.

Beyond the science of Cosmology@Home your words remind me that sience can act as a great way to bring people from all walks of life together behind a common and worthwhile purpose. Participation in whatever way raises us up as individuals and makes us a part of an adventure that is larger than ourselves.

This really is at the core of why enlightened societies choose to pursue fundamental questions such as the ones at the heart of Cosmology@Home and many other participatory computing projects.

And if you have not posted yet, please do not hesitate.

Again, you are all welcome here and I thank you for your valuable contributions.

Ben Wandelt


35) Forums : Technical Support : Can't Seem to Modify Preferences (Message 10328)
Posted 3 Mar 2012 by Profile Benjamin Wandelt
Post:
Hi -

Could you check again? We've been doing some work on the data base.

Best,
Ben
36) Forums : Announcements : Filesystem upgrade! (Message 10326)
Posted 2 Mar 2012 by Profile Benjamin Wandelt
Post:
HI again -

Another update.

1) As some of you have noticed, in addition to the file system problem, the team database was temporarily corrupted. It is possible that those two events were linked.

2) Thanks to the intervention of the Astronomy system administrator this problem was resolved and the database was repaired.

3) I just ordered 4 TB of new disk space to give us some breathing room in the file system.

4) We will take the disk upgrade as an opportunity to a more substantial upgrade of the BOINC software, which may fix one or two other annoying bugs that people here have had to put up with (that did not affect scientific functioning of the project, but were annoying nevertheless).

5) I will keep you updated and make a news item when the system goes down for the upgrade.

Thanks for all your patience and continuing support.

All the best, and happy crunching!

Ben
37) Forums : Announcements : Filesystem upgrade! (Message 10266)
Posted 22 Feb 2012 by Profile Benjamin Wandelt
Post:
Hi everyone -

Just a quick update as I am working on this.

First of all, yes, this is frustrating, and not just for you.

Now for some good news:

1) I managed to get help by a very competent system administrator at Illinois.

2) In the short term the disk space problem has been resolved through a house-cleaning and purging old files. (That was the quick fix idea that I mentioned).

3) I am ordering 4 TB of additional disk space and will have that installed asap.

Now some bad news:

The system administrator has discovered that the team data base needs to be repaired. There is an access problem that we have to solve for him (since the old system administrator set a mysql root password and we are trying to get in touch with him).

Back to the good news:

Once that is done we will be able to resume operations.

Then in the near future there will be a planned downtime for an operating system upgrade and an installation of the new disks.

Again, thank you for your patience and continued support.

All the best,
Ben
38) Forums : Technical Support : Missing .ini file on download. (Message 9913)
Posted 24 Jan 2012 by Profile Benjamin Wandelt
Post:
Thank you for this contribution!

Best regards,

Ben
39) Forums : Technical Support : Missing .ini file on download. (Message 9756)
Posted 15 Dec 2011 by Profile Benjamin Wandelt
Post:
Hi robertmiles

My apologies for this persistent problem. This is clearly a problem in the code that generates the work packages. I'll try to find the bug. What's puzzling is that this problem has apparently started occurring only relatively recently (May 2011). The current workaround is to abort these packages and load new ones.

Ben


40) Forums : Cosmology and Astronomy : Planck Mission Updates! (Message 9721)
Posted 2 Dec 2011 by Profile Benjamin Wandelt
Post:
Thanks Faik -

since this is a long link to copy or retype, here is a clickable version of this link to Planck-related videos and images.

Check out the BBCode tags (for a short description click on the left of the field where you edit your post) to see how to include clickable links in your posts - you use the
 [url=...] [/url] 
tag.

Best,
Ben

Edit: I just realized that code is shown black on black - I'll update the style of the website to show it in yellow.
Edit: Done.


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