Archive for the ‘STScI’ category

Science vs Consumer Detectors: Thank you, Mary.

August 4, 2009

I have been trying to figure out recently why people don’t understand what IR detector data looks like, given that we have examples and studies and in a few cases specifications of what we’ll get from JWST, and examples and analysis of NICMOS, Spitzer and some Keck data.  My wife explained it to me, and then I looked at the numbers.  She’s right, and I wanted to publicly thank her.

We have some simulated data, a cutout of which is shown here, that gives you the general idea of what the data will look like if it’s pretty good.  Jay Anderson (STScI) did this simulation.

Simulated NIRCam Data with 1% bad pixels

Simulated NIRCam Data with 1% bad pixels

That picture is 1 percent bad pixels, which is pretty good.  For the roughly 4 megapixel NIRCam, you’d expect to get 40,000 bad pixels, before you add any cosmic rays.  That means one in every hundred pixels is a bad one.  It could be one in 50.  And still, that’s pretty good.



Macs take over astronomy

March 11, 2008

Okay, maybe not all of astronomy, but I got these numbers yesterday from the people who handle HST proposal submissions:

Platform     Proposals
Mac OS X        492
Linux           297
Windows         115
Sparc Sun        46
Not Given        11

Five years ago, less than ten percent of proposals were done on Macs. This year it’s more than half.

Of course, the more interesting numbers would be the percentage on each operating system for accepted proposals, but we won’t know who is accepted until the end of May.

(Put another way, what I’d like to know is whether the platform used for submission predicts, even weakly, proposal acceptance, and whether the proportion of platforms for accepted proposals predicts future submission platforms.)

Is Junk E-mail Impeding Postal Mail?

June 17, 2007

I get 200-300 email messages a day in my three accounts, about two-thirds of them in my STScI (work) account.

On a recent day, the Institute junk mail filters caught just 21 messages, one of which was a false-positive. 39 other obvious spam, including several with a charming oversize image of a flayed penis, were not caught. Since the filters catch only a quarter to a third of my spam, and flags things that I thought were on my allowed senders list, I have to check them all.

The false positive is a puzzle: Bruce Schneier’s Crypto-Gram. *.SCHNEIER.COM was on my whitelist, but it seems Bruce switched the return address from MAIL.SCHNEIER.COM to simply SCHNEIER.COM at some point. Still, the message is long, but is all text with some embedded URLs. I don’t know why it’s marked as spam. I get a very similar daily summary from Northrop-Grumman of new JWST documents, but has not (yet) been flagged as spam.

The effect, though, is that I have to scan the envelope information of all the spam messages, 60 to 80 a day, looking for false-positives. That’s almost half of my STScI mail, due to the combination of poor rules and a clunky, unreliable whitelist interface. Gmail is a completely different experience, with less total spam, and very rarely do I get a false positive. Better yet, telling Gmail that it guessed wrong (either way) is quick and easy.

What I find interesting is that I use the same technique for junk postal mail. I get 5 to 10 pieces of mail per day about 75% of it junk mail. I scan the envelopes, looking for obvious ads, but also for credit card, refinancing, and home equity loan offers. I discard (shred, actually) most envelopes without opening them. It would only be slightly more efficient to shred them directly into a recycle bin at the mailbox.

But I also get false positives. My mortgage company needed my signature on some paperwork to clarify the agency relationship for tax purposes. From my perspective, the envelope information on the tax-related documents looked the same as the envelope information for the refinance-offer-of-the-month. So I shredded it. Twice.

The first bit of good news is that I get very little porn (or near-porn, “male enhancement”) junk paper mail.

The second bit of good news is that there are things we can do (but don’t) to improve email filtering, like domain keys, authenticated from addresses, and improved blacklist and whitelist user interfaces. We don’t do those things, but we could.

I wonder if the overwhelming load of crap in electronic mail is causing me to look differently at paper mail, or if the overwhelming success of electronic direct mail advertising has increased the volume and sophistication of paper-based direct mail ads. Is my experience unusual? Have others thrown away non-junk paper mail because they are simply tired of plowing through junk mail?

Or is this just the reverse of the Al Gore thinking model: New ways of thinking about old technologies. That, at least, would be amusing.


Tim Wise followup: Implicit Preference?

June 15, 2007

Harvard University has a series of tests of implicit assumptions people make, under the aegis of Project Implicit.

I took a couple of the demo tests, the African American – European American IAT and the Gender – Science IAT. According to the tests, I have a slight automatic preference for black people over white people, and moderate association of male with science and female with liberal arts.

If you register and follow the link to the research side of the project, you get different tests. One of the ones I took was whether I have a preference for “lucky” people. For example, one guy got run over by a bus, while another won a car in a raffle. It turns out I have no preference.

I am occasionally amazed at how preferences develop, and how our unconscious, or at least unacknowledged, preferences affect the decisions we make and the assumptions we act on.

Upper middle class PTA leaders assume that the people around them grew up the same way they did, and it never occurs to them that one of their number grew up poor. We get something of a break on the religious issue, because there are enough Muslims, Jews and Bhuddists to avoid the automatic assumption that everyone is Christian, but they were shocked to find a Wiccan. (Atheists don’t even surprise even the most Christian among them.) They assume that, because they want to “protect” their daughter from information about sexuality so that she’ll wait until marriage, that I want the same thing, and am trying to provide the same “protection.” In fact, the most shocking thing I think I’ve ever said to another parent was that I hoped my daughter would learn a lot about sex, so that she could make her own choices. I hope she’ll wait until she’s old enough to know her own mind, but I would be surprised and concerned if she committed to a marriage with no experience at all. From the look on that mom’s face, you’d have thought I was pimping my daughter.

People do have preferences about who they like being around. We build “tribes” around common interests, both online and offline. I value diversity, and I also value shared goals and aspirations. Building those communities based on expressed preferences is healthy. Picking your associates based on your assumptions, particularly assumptions about skin color and gender isn’t tribalism, it’s racism and sexism.

I’m fortunate to have grown up in a racially mixed environment, and to have been exposed to both poverty and wealth. While I could have made different choices and gotten a better technical education, I think having a liberal arts background has made me a wider person.

So to torture the metaphor at the end of Tim Wise’s talk, I recognize the stinking pot of two-day-old gumbo, and I’m willing to help clean up. The problem is, I don’t think I know how to clean it. I’m inclined to throw it out, but I fear replacing the pot would be expensive, and dangerous.

So, watch the talk, and think about the problem. If you have ideas for how to clean the pot, I’d like to hear them.

Looking for Help on FOS

June 14, 2007

We are looking for help for the Flight Operations Subsystem team.

The position is posted internally now, but will be external any time. The ideal person would have experience with control center systems, ideally building one, and be experienced in working with developer, astronomer and system engineering communities here and at Goddard. This is work that Carl Biagetti is leading, and Carey Myers is starting to work on.

To quote me:

The JWST Flight Operations Subsystem Engineer will be responsible for refining the FOS operations concept, defining systems requirements, interfaces and architecture as well as supporting the development of FOS elements and their integration with the JWST Science and Operations Center. The FOS Systems Engineer will work under the direction of the STScI FOS Systems Engineering Lead as a member of a concurrent engineering team responsible for the FOS Ground System. This position will require interaction with JWST science, operations and development staff, the JWST NASA GSFC project, JWST contractors and representatives of other missions to achieve the work objectives.

Knowledge of the state of the art in satellite control center systems is required. This includes experience with the following: one or more NASA GSFC developed systems such as TPOCC, ITOS, ASSIST, HST CCS; one or more commercial systems such as EPOCH, ECLIPSE or OS/COMET; ground station and communications satellite interfaces; satellite command procedures languages; satellite control center operations procedures.

If you are somebody like that, or know somebody like that, I want to talk to you, even if you aren’t interested in doing this kind of work yourself. (For one thing, I can use help on the interview team!)

This is new stuff for us, so it’s a challenging, exciting opportunity.


It’s not what the software does, it’s what the user does.

May 30, 2007

hugh macleod at Gaping Void does these great little cartoons, “drawn on the back of business cards.”   First, that’s a cool idea.  It’s a great size, and it lets you express just one idea in a little tiny format with which people are familiar.

This cartoon in particular says something very insightful, both about PowerPoint and about software in general.  I agree with the sentiment, though I have a quibble.

The problem Tufte and others point out is not that PowerPoint is abused, it is that the particular cognitive style of PowerPoint encourages lazy thinking, and poor communication.

When we’re building software, in my view, we should be concerned about the correctness of algorithms, using appropriate design patterns, and building designs that are sustainable and maintainable.  It is also essential that we build systems that users readily understand, and that encourage users to build correct results.

Because technology matters, but people matter most.


Single signon, but not what you wanted.

May 30, 2007

I previously discussed user-level security. This morning, I ran across this story about system administrators, and how they manage security.

It seems that system administrators are pretty careless with root-level security, and that the key to getting root may be finding the right Post-It notes. I keep the root passwords for all my systems (and a few passphrases for rarely-used encrypted volumes) on paper, but the paper is in my home safe. In fairness, I should add that they are in the safe not for security reasons, but to protect against fire.

I believe that the Institute uses a single password for all the Windows systems admin accounts. (Because I’ve seen sysadmin’s go looking for the password, which at least does get changed occasionally.) I’ll let you google methods for recovering passwords from a laptop you’ve managed to capture, and point out what this means: Once you have admin access to one Institute Windows system, you have them all. I don’t know for sure that the Macs use the same scheme, but I bet they do. I’ll be they have (one) different password, though.

Carl and I touched on this in a discussion yesterday: We rather doubt that the Institute has a current, accurate list of the computing assets we own, and that we permit to have access to our domain. In addition to being a problem from the standpoint of property management and effective use of resources, this is also a security problem.

Addressing this requires devoting time and attention, and people to work on it, all of which are in somewhat short supply right now. Hopefully it won’t take an actual catastrophe to up the priority.