agrajag

Takoma Park FTW

jpenderg@cs.oberlin.edu — Tue, 03 Nov 2009 23:13:01 GMT

I just voted in the first open source, voter verifiable municipal election.
Takoma Park rocks!

Mathematicians Finally Do Something Useful

jpenderg@cs.oberlin.edu — Wed, 26 Aug 2009 15:23:00 GMT

For hobbitkicker and other zombie fans: When Zombies Attack!: Mathematical Modelling of an Outbreak of Zombie Infection

Good News from the Bench

jpenderg@cs.oberlin.edu — Tue, 21 Jul 2009 19:34:54 GMT

A federal appeals court has ruled that DC's roadblocks in Trinidad (the neighborhood in NE DC) were unconsitutional (full story). Trinidad is a rough neighborhood, I go there (at least in passing on my way to H street), and have friends who live there. The homicides were very concerning, and I don't doubt DC AG Nickles when he says the checkpoints were "effective". But the whole point of having a bill-of-rights is that effective law enforcement techniques limit freedom. I'm always glad to see the courts deciding for what is right instead of what is easy (even if it may put me or those I care about at risk).

Hydrodynamic Building Set!

jpenderg@cs.oberlin.edu — Wed, 15 Jul 2009 13:34:34 GMT

I just bought myself a Hydrodynamic Building Set. It's pretty awesome.

jpenderg@cs.oberlin.edu — Mon, 13 Jul 2009 12:21:43 GMT

Hey manko, have you and your young minions discovered TV Tropes yet? (I just found it thanks to today's xkcd, and much like the strip's protagonist could waste all day clicking about).

repne scasb

jpenderg@cs.oberlin.edu — Tue, 30 Jun 2009 15:52:51 GMT

Fun to say and fun to execute.
"Repeat while not equal scan string bytes"
Search for the first instance of the byte ax in the first ecx bytes of the string referenced by edi. Decrements ecx and either increments or decrements edi (based on the df flag of the eflags register) at each iteration.

I've been staring at intel assembly for far too long.

Strangely Attractive

jpenderg@cs.oberlin.edu — Tue, 09 Jun 2009 13:49:11 GMT

This is a followup to yesterdays chaotic image.
I've modified my Processing program to animate the a,b,c, and d parameters.
Try the applet.
To toggle animation on/off for a parameter just hit the corresponding key ('a','b','c', or 'd').

On an unrelated note... nomoresquid, there was a moth in our cat's water bowl last night that seemed to be drowned. But when I picked it out of the water it started twitching in the sink and stood up (it may even have flown off, but I think I squished it). Maybe there was salt in the sink?

ETA: There was a bug in my code, I trampled x before calculating the new y. This is fixed now. Also you can change the number of iterations using '+' and '-'.

Cause Nothing Says Monday Morning Like Chaos

jpenderg@cs.oberlin.edu — Mon, 08 Jun 2009 14:32:34 GMT

Processing Code:


float x = 0.1;
 float y = 0.1;
 float a = -0.5318;
 float b = 2.785;
 float c = 2.685;
 float d = -0.9887;
 
int h   = 800;
int w   = 800;

size(h,w);
background(255);


for(int i=0;i < 1000000;i++){
  x = sin(a*x) + c*sin(a*y);
  y = sin(b*x) + d*sin(b*y);
}

for(int i=0;i < 1000000;i++){
  stroke(0);
  point( (w/6) * (x+ 3) ,(h/6) * (y + 3));
  x = sin(a*x) + c*sin(a*y);
  y = sin(b*x) + d*sin(b*y);
}

You can play with the a, b, c, and d variables to generate different pretty pictures.

(equations copied from Chaos in Wonderland by Clifford A. Pickover).

Staff Class?

jpenderg@cs.oberlin.edu — Tue, 19 May 2009 11:16:06 GMT

Hey DC Area LJ folks.
Any of you interested in taking an intro to staff manipulation (both grip & contact) class?
I'm trying to put one together for the summer session at contradiction dance. To get the slot I need at least 5 students. Anyone interested please let me know what day/time would be most convenient for you. Currently earlier in the week looks more likely (monday, tuesday, or wednesday evening). I have received a vote for saturday afternoon, but that would require finding a sub or cancelling at least two classes.

Hey MaxMSP lovers

jpenderg@cs.oberlin.edu — Sun, 10 May 2009 14:45:56 GMT

I just happened upon Pure Data, an open source alternative developed by the original designer of the Max language. I have no idea how good it is (and am not really in a position to evaluate it what with the musical illiteracy and all). Just thought someone out there might be thinking "damn, I love MaxMSP but it is really expensive/won't run on my platform"

It's Official

jpenderg@cs.oberlin.edu — Fri, 24 Apr 2009 10:53:08 GMT

We're Takoma Park hippies.

Bacon Lance

jpenderg@cs.oberlin.edu — Thu, 16 Apr 2009 23:57:00 GMT

Because everything is better with bacon

Obama's DOJ

jpenderg@cs.oberlin.edu — Tue, 07 Apr 2009 16:13:53 GMT

This is very disturbing.

jpenderg@cs.oberlin.edu — Tue, 07 Apr 2009 10:58:34 GMT

aaron@jabberwock$ uname -a
Darwin jabberwock.wonderland 9.6.0 Darwin Kernel Version 9.6.0: Mon Nov 24 17:39:01 PST 2008; root:xnu-1228.9.59~1/RELEASE_PPC Power Macintosh
aaron@jabberwock$ ssh dodo
Last login: Tue Apr 7 06:50:01 2009 from jabberwock.wonderland
aaron@dodo$ uname -a
IRIX64 dodo 6.5 01062343 IP30
aaron@dodo$ logout
Connection to dodo closed.
aaron@jabberwock$ ssh walrus
Last login: Mon Sep 24 11:53:26 2007 from jabberwock.wond
(c)Copyright 1983-2000 Hewlett-Packard Co., All Rights Reserved.
(c)Copyright 1979, 1980, 1983, 1985-1993 The Regents of the Univ. of California
(c)Copyright 1980, 1984, 1986 Novell, Inc.
(c)Copyright 1986-1992 Sun Microsystems, Inc.
(c)Copyright 1985, 1986, 1988 Massachusetts Institute of Technology
(c)Copyright 1989-1993 The Open Software Foundation, Inc.
(c)Copyright 1986 Digital Equipment Corp.
(c)Copyright 1990 Motorola, Inc.
(c)Copyright 1990, 1991, 1992 Cornell University
(c)Copyright 1989-1991 The University of Maryland
(c)Copyright 1988 Carnegie Mellon University
(c)Copyright 1991-2000 Mentat Inc.
(c)Copyright 1996 Morning Star Technologies, Inc.
(c)Copyright 1996 Progressive Systems, Inc.
(c)Copyright 1991-2000 Isogon Corporation, All Rights Reserved.

RESTRICTED RIGHTS LEGEND
Use, duplication, or disclosure by the U.S. Government is subject to
restrictions as set forth in sub-paragraph (c)(1)(ii) of the Rights in
Technical Data and Computer Software clause in DFARS 252.227-7013.

Hewlett-Packard Company
3000 Hanover Street
Palo Alto, CA 94304 U.S.A.

Rights for non-DOD U.S. Government Departments and Agencies are as set
forth in FAR 52.227-19(c)(1,2).
bash-2.04$ uname -a
HP-UX Quake B.11.11 U 9000/785 2001788831 unlimited-user license
bash-2.04$ logout
logout
Connection to walrus closed.
aaron@jabberwock$ rsh caterpillar
Password:
Last login: Tue Apr 7 07:54:45 from jabberwock.wonde
aaron@caterpillar$ hostinfo
Mach kernel version:
NeXT Mach 3.3: Tue Jul 13 10:33:44 PDT 1999; root(rcbuilder):mk-171.14.obj~22/RC_m68k/RELEASE_M68K

Kernel configured for a single processor only.
1 processor is physically available.
Processor type: MC680x0 (68040)
Processor speed: 33 MHz
Processor active: 0
System type: 5
Board revision: 0xf
Primary memory available: 96.00 megabytes.
Default processor set: 45 tasks, 71 threads, 1 processors
Load average: 0.06, Mach factor: 0.93
aaron@caterpillar$ logout
rlogin: connection closed.
aaron@jabberwock$

DIY 1980s Supercomputer

jpenderg@cs.oberlin.edu — Fri, 20 Feb 2009 17:10:39 GMT

This is really cool.

Video

jpenderg@cs.oberlin.edu — Mon, 09 Feb 2009 21:43:00 GMT

jpenderg@cs.oberlin.edu — Mon, 09 Feb 2009 13:14:36 GMT

Reposted from chilimuffin, primarily for the benefit of kiaroskuro:

snapped up happily from g-kate.... far too much suffering and propagation of misinformation has occurred because of this man's falsification of his data. When herd immunity falls, it's usually not the kids of the Jenny McCarthys who suffer.....

MMR doctor Andrew Wakefield fixed data on autism

by Brian Deer
The Sunday Times
February 08, 2009

THE doctor who sparked the scare over the safety of the MMR vaccine for children changed and misreported results in his research, creating the appearance of a possible link with autism, a Sunday Times investigation has found.

Confidential medical documents and interviews with witnesses have established that Andrew Wakefield manipulated patients’ data, which triggered fears that the MMR triple vaccine to protect against measles, mumps and rubella was linked to the condition.

The research was published in February 1998 in an article in The Lancet medical journal. It claimed that the families of eight out of 12 children attending a routine clinic at the hospital had blamed MMR for their autism, and said that problems came on within days of the jab. The team also claimed to have discovered a new inflammatory bowel disease underlying the children’s conditions.

However, our investigation, confirmed by evidence presented to the General Medical Council (GMC), reveals that: In most of the 12 cases, the children’s ailments as described in The Lancet were different from their hospital and GP records. Although the research paper claimed that problems came on within days of the jab, in only one case did medical records suggest this was true, and in many of the cases medical concerns had been raised before the children were vaccinated. Hospital pathologists, looking for inflammatory bowel disease, reported in the majority of cases that the gut was normal. This was then reviewed and the Lancet paper showed them as abnormal.

Despite involving just a dozen children, the 1998 paper’s impact was extraordinary. After its publication, rates of inoculation fell from 92% to below 80%. Populations acquire “herd immunity” from measles when more than 95% of people have been vaccinated.

Last week official figures showed that 1,348 confirmed cases of measles in England and Wales were reported last year, compared with 56 in 1998. Two children have died of the disease.

With two professors, John Walker-Smith and Simon Murch, Wakefield is defending himself against allegations of serious professional misconduct brought by the GMC. The charges relate to ethical aspects of the project, not its findings. All three men deny any misconduct.

Through his lawyers, Wakefield this weekend denied the issues raised by our investigation, but declined to comment further.

Odd

jpenderg@cs.oberlin.edu — Sun, 25 Jan 2009 16:27:30 GMT

This morning I found a pair of green rubber lab safety gloves on the floor of my study. Neither erin, nor I own a pair of green rubber lab safety glvoes.
Curious.

ETA: Or maybe yesterday I unpacked the beer brewing kit my sister gave me and it included a pair of green rubber lab safety gloves for sanitizing things. It's a possibility; but far less interesting than spooky lab techs sneaking into my house in the middle of the night to do some chemistry and then forgetting a pair of gloves.

Code Blog

jpenderg@cs.oberlin.edu — Sun, 25 Jan 2009 00:28:59 GMT

I started a blog for posting "interesting" code. Most readers of my lj are unlikely to be particularly interested. But some of you may be. So check it out: Code Dump

All Too Familiar

jpenderg@cs.oberlin.edu — Wed, 14 Jan 2009 13:38:50 GMT

(taken from xkcd originally published under Creative Commons Attribution-nonCommercial license).

Why Software Sucks

jpenderg@cs.oberlin.edu — Thu, 08 Jan 2009 21:04:47 GMT

As a computer user I often bemoan the fact that software sucks (and the two corrolaries: free software sucks, and proprietary software sucks). I'm sure pretty much everyone can sympathize with this.

It is only very occasionally, either through my work as a computer security researcher or through my own peculiar meandering across the collected knowledge of the internet, that I come upon a really good example of WHY software sucks.

It is tempting to believe that software really shouldn't be so difficult. It seems like most of what software is supposed to do isn't really that difficult. For example, keeping time. Like many, I rely on my computer/cell phone/ipod to tell me what time it is, and on the whole it does a pretty good job. But that's because I don't care precisely what time it actually is, in fact I probably have a +/- 5 minute tolerance most of the time and never more than a +/- 1 minute tolerance. So the fact that December 31, 2008 had 86401 seconds instead of 86400 made no direct impact on my life.

Some people care.

And I don't mean care as an intellectual curiosity, they really really care.

Stock trading is a good example. The stock market requires that lots of computers agree *precisely* on what time it is. If one computer thinks it is 4:59:59.999 and another thinks it is 5:00:00.0000 then millions of dollars could simply disappear (although I assume there are safeguards to prevent this).

This kind of thing actually comes up pretty frequently when you start really caring about the fine details of software (especially along the computer/physical world boundary). Leap seconds are a good example because they are (apparently) arbitrary; there is no algorithm that software developers can use to predict leap seconds, they just happen occasionally.

This thread on the linux kernel mailing list (warning, this is a deeply technical mailing list full of smart opinionated kernel developers; it is generally not for the faint of heart) provides what I find to be a fascinating look at why writing correct software is so difficult (both from a technical and a political perspective).

jpenderg@cs.oberlin.edu — Sun, 04 Jan 2009 15:09:19 GMT

They've announced the 11th doctor: Matt Smith. He starts in 2010.
Article: http://news.bbc.co.uk/2/hi/entertainment/7808697.stm

Event Announcement: All Lit Up

jpenderg@cs.oberlin.edu — Wed, 26 Nov 2008 19:24:45 GMT

"All Lit Up" at Contradiction Dance!
December 13 at 3pm. $10 for fun, food, and performances from students and the resident companies: Contradiction Dance, Dance Afire, A Different Drum & Mini-Shock! DON'T MISS IT!!

Contact Staff Workshop

jpenderg@cs.oberlin.edu — Wed, 26 Nov 2008 17:30:01 GMT

December 4th @ 9:00 PM
Contradiction Dance Studio
7014 Westmoreland Ave, ste A
Takoma Park, MD 20912

Updated to fix month.

HIPS Show

jpenderg@cs.oberlin.edu — Fri, 07 Nov 2008 11:43:02 GMT

For those who don't know, last night was the annual HIPS benefit show at the palace. It was as always a fantastic show and a fun night. I was really honored to contribute as a performer this year; many of the others were truly professional performers (I view myself as a quasi-professional performer; I'm mostly just in it for fun) and it was amazing to perform along side them and to receive their praise on my act. HIPS is a terrific organization that does really valuable work for the city. I couldn't contribute much monetarily this year (due to house stuff) so I'm glad I was able to do something to help support them.