Jamming Flagpoles

Today I read a report about Iran's alleged "flagpole jamming network".  Reading all of this, it became plainly obvious that, "of course this is a method they're using."  Here in the States, we already use flagpoles to conceal cellular communications towers.  You can see an example of such towers here.  So, it makes a certain amount of sense that tyrants (Islamofascists, Democrats, Republicans, etc.) would use similar means to conceal a "secret" jamming network.

The one problem I have with the story reported by Fox news is simply this: a jamming system requires both power and communications connectivity.  I.e. you can't just throw a flagpole in the ground and magically make it a part of a larger jamming network. Hasn't anyone reported seemingly excessive communications or electrical work being done around these flagpoles?  Instead of offering subjective reports about juvenile cancer rates, etc., why not identify the concrete things that would prove the purpose of these mystery towers?

Media.

Read More

Sex and its irrationality

I am probably your average heterosexual male specimen. Having gone through a younger period where sex is at the top of my list of priorities, my hormones have calmed down somewhat and now it appears I can finally examine sex with more rationality.

Recently it is beginning to get to me that sex is not something that one can rationalize. It lies outside the realms of rationality. The fact that a heterosexual male gets aroused by the sight of breasts or the vagina is not something one can deconstruct. In fact, there is nothing inherently attractive about these things other than the fact that millions of years of evolution have built their sense of attractiveness into us, without which our species cannot survive. If an alien from another planet were to land on Earth, they will never understand why we find breasts or vagina sexy, much as we can understand how a peahen will find the large and bright tail of a peacock sexy.

And we have discovered for a long time that there is a large variety of sexuality outside of the standard male-female model. You have the asexual (not interested in sex), homosexual (interested in same sex), heterosexual (interested in opposite sex), bisexual (interested in both sexes), transgender (female persona trapped in a male body, and vice versa). Within a particular category, there are also huge variations i.e. interest in different sexual organs, or even symbolism of sex (eg. brassiere or panties).

It is probably unique to the human species that we have the mental capacity to tie ourselves in knots over variances in sexuality outside of the standard model. There have probably been more debates about the morality/immorality of sexual variances than how to rid our world of hunger. Heterosexuality, being the majority, has always occupied the moral high ground. Other forms of sexuality have always been the deviant form. In some countries, being homosexual or transgender can get you killed. In fact, I have encountered few people who even understand the difference between being homosexual and being transgender. Most people still associate being effeminate as being homosexual (for males), for example.

It puzzles me to no end how most people do not question the irrationality of heterosex itself, that finding sexual organs of the opposite sex attractive is just as illogical as finding sexuals organs of the same sex attractive. To most people, heterosex is just "natural", whereas other forms of sexuality are not. This is crazy, and how people can live with that conclusion is beyond me. It is probably the highest form of prejudice there ever is, that your irrationality is somehow more "natural" than some other irrationality. I mean, this is not some argument over whether one algorithm is better than another, because then you can use logic/numbers to justify your decision. This is a case of my preference is more "natural" than yours and 1) that's it, 2) end of discussion, 3) you are a deviant/outcast.

Is it just me, or does anyone else find this crazy as well?

Read More

Roomba navigation algorithm

I have been a long time user of the Roomba vacuum robot, starting from version 1 till now. It has made a big difference to my life, and I enthusiastically recommend it to all my friends.

One thing that stands Roomba apart from other vacuum robot is its navigation algorithm. There is no high-level mapping involved. Instead it uses localized decision making, much like how insects forage for food:

Our robot computes its algorithm 67 times every second, constantly stitching together information about its environment and recomputing its path. When it starts you’ll notice a spiral pattern, it’ll spiral out over a larger and larger area until it hits an object. When it finds an object, it will follow along the edge of that object for a period of time, and then it will start cris-crossing, trying to figure out the largest distance it can go without hitting another object, and that’s helping it figure out how large the space is, but if it goes for too long a period of time without hitting a wall, it’s going to start spiraling again, because it figures it’s in a wide open space, and it’s constantly calculating and figuring that out. It’s similar with the dirt sensors underneath, when one of those sensors gets tripped it changes its behaviors to cover that area. It will then go off in search of another dirty area in a straight path. The way that these different patterns pile on to each other as they go, we know that that is the most effective way to cover a room. The patterns that we chose and how the algorithm was originally developed was based off of behavior-based algorithms born out of MIT studying animals and how they go about searching areas for food. When you look at how ants and bees go out and they search areas, these kinds of coverage and figuring all of that out comes from that research. It’s not exact, obviously, I’m not saying we’re honeybees, but it’s that understanding of how to search out an area in nature that is the basis behind how our adaptive technology is developed.

The algorithm is actually quite effective and robust in the real world. For a short while, I used to house two cats in a room, and you can imagine how dusty that was. Roomba never failed to clean up the room for me after I left it to its devices. It was squeaky clean after each session, and all I had to do after that was to give the wooden floor a quick mop.

Don't take my word for it. Check out this video providing a time-lapsed coverage test of various vacuum robots, including The Roomba 5 series.

However, I never fail to notice, both online and off, how Roomba's navigation algorithm invokes all kinds of negative feeling in users. Comments typically are of the types:

... It is just going in random directions
... Personally I will not vacuum like that
... Why does it go over the same area twice?
... It is not very efficient, it takes too long 

I have seen people just standing there and supervising/criticizing their robot's every move! This is crazy! Do you stand there and supervise your washing machine? I mean, you just dump your clothes in, set a wash cycle, and come back in 45 mins or whatever. What's so difficult about that? Instead you have people just hanging around and second guessing every move the robot makes. Absurd!

I can understand maybe a robot vacuum cleaner is something new to a lot of people, it hasn't become quite as mundane as a washing machine. Or maybe a localized or bottom up algorithm is just harder to understand/accept compared to a top-down algorithm. Rodney Brooks, the co-founder of iRobot, the company that makes Roomba, is a pioneer in the field of bottom-up robotics. He famously created robotic insects that do not have a central "brain", but instead make localized decisions based on the feedback from various sensors (much like the Roomba). In the physical world, that approach turns out to be extremely robust and resilient.

AFAIK iRobot has never organized any campaign to dispel such negativity. I guess maybe it is just too difficult and technical to make people understand that a bottom-up approach is superior to a top-down (mapping) approach. I hope I can make a small difference by blogging about this here. Roomba's navigation algorithm in the real world is robust. You can move furniture around while the robot is running and not have to worry that it won't come back again. You can let it bump into your foot if you are doing stuff in the same room while it is running, but you can be assured that will not have a large impact on what it is doing.

You don't want a robot to vacuum like you do. Otherwise, cars will have legs, and washing machines will have arms. Just clear the room, set the robot down, let it run, grab a cuppa and come back an hour later. The room will be clean. Trust me.

Read More

How to make your OpenBox awesome

As a long-time Linux geek, I've discovered that there are nice aspects of GNOME/KDE, and then there's all the horrifying bits.  After almost 20 years of desktop Linux use, I've concluded that "lighter is better."  I.e. there's no real benefit to having all the bells and whistles turned on.  That's what lead me to OpenBox.

Anyone who has run OpenBox is familiar with ~/.config/openbox/autostart.sh... or at least they should be.  In case you aren't, here's the crux of it -- the autostart.sh script runs when OB starts-up, and its the vehicle through which you can start all the bits and pieces of the desktop that you might need.  Here's my autostart.sh:

#
# Openbox config for the ultimate desktop 
# 

#### policykit manager
# allows us to manage networks and other things that require root priv.
(sleep 10 && /usr/lib/policykit-1-gnome/polkit-gnome-authentication-agent-1) &

#### gnome settings daemon 
# allows us to use the gnome tools for things like display and mouse
(gnome-settings-daemon) & 

#### mount encrypted disks and set desktop wallpaper
(/home/cjs/bin/mntenc && nitrogen --set-zoom-fill /home/cjs/mine/pics/backgrounds/current.jpg ) &

#### Enable power management
# we use xfce because the gnome-power-manager went away (as a systray icon anyways)
#(gnome-power-manager) & #this went away in Debian Sid around Dec '11
(xfce4-power-manager) &

#### Thunar Daemon
# handles automounting disks, etc.
(thunar --daemon) &

#### Tint2
# our panel
(tint2) &

#### Screensaver
(xscreensaver -no-splash) &

#### Synapse
# synapse is a key-stroke app-launcher, like Gnome-DO
(synapse -s) &

#### DropBox
# sync files between multiple systems
(sleep 2s && dropbox start) &

## Launch network manager applet
# 2012/01/07 -- this has been getting launched twice, presumably by gnome-settings-daemon?
#(sleep 4s && nm-applet) &

#### volumeicon 
# allows us to control volume from an icon in the system tray
(sleep 3s && volumeicon) &

#### Clipboard manager
# parcellite is a bigger/better utility
(sleep 3s && parcellite) &

## start xsnow!
#(sleep 3s && xsnow -notrees -nokeepsnow -nosanta) &

So, in case all of this is completely Greek to you, I've included comments.  This script works provided you've got tint2, parcellite, xscreensaver, dropbox, volumeicon, and thunar installed, and in your execution path.  This script also assumes that you've got the default GNOME desktop installed for such things as settings and authentication.  The point being is that you can use this even on the default Debian 6 install, and achieve a highly functional desktop without the overhead you'd experience with a full GNOME or KDE desktop.

Read More