Don't use credit cards abroad

It used to be that when traveling abroad, paying with a credit card was the smartest way to avoid paying outrageous currency conversion charges.  The currency conversion places at airports were, and still are, a ripoff -- often you'll lose 5-10 % of your money when you exchange dollars for the local currency.  This is because those places hit you in two ways: (1) you pay a commission to change money (2) the rate you are offered is much worse than the market rate.  The credit card companies, on the other hand, would charge no fees or commissions. And to make things better, they do the conversion at the interbank rates -- the best rates possible.

Now, though, credit card companies charge 3% "foreign transaction fees" which alter the balance significantly.  For example, a $9.85 purchase in Australian dollars was converted to $8.42, and we were charged an additional 3%.  This brings the cost of each Australian dollar to 88.05 cents. A better deal is what I got with my ATM card. Because I bank at a small bank which has no ATM fees, the $300  I withdrew at an ATM cost me $257.27, meaning that the effective rate was only 85.76 cents.  There were no extra fees or surcharges.   I save $3 on every $100 I spent using cash (from the ATM) rather than using my credit card.

Bottom line: When traveling abroad, use your ATM card to withdraw cash in the local currency. Then pay for everything with cash.  From now on, I'm going to use my credit card only for things like hotels where I can not pay with cash.  If your bank charges for ATM usage, just withdraw a lot of money at once, so that you pay the surcharge only once.  For example, if your bank's ATM surcharge is $3, you come out ahead as long as you withdraw more than $100 U.S. dollars at a time.

Custom compression algorithms: worth the cost?

I am in San Diego at a conference on satellite data handling and compression.  This is not really my field, but the conference chair emailed me a few months ago asking if I'd be willing to come and give a talk on how radar data are compressed for storage and transmission.

"Are you sure," I emailed him, explaining that the radar program uses only off-the-shelf compression techniques because custom compression techniques provided only a 10% improvement over off-the-shelf solutions such as bzip2.  He replied that this was fine.

This morning, my talk was sandwiched between 6 other talks on compression.  Each of them demonstrated a 5 to 15% improvement over JPEG 2000. So, you can imagine how the thrust of my talk -- that custom compression techniques that provided only incremental improvements were not cost effective -- carried over.

"What would be the threshold at which it would cost effective," one of the members in the audience asked, "would 100% be enough if the space agency would maintain and release compression and decompression software for use by anyone?"

"Maybe,:" I replied, digging the hole even further.  "Remember that this code needs to be maintained, and updated for new languages and platforms.  This would cost at least 150,000 dollars per year.  You have to justify that the saved storage and transmission costs are sufficient to overcome that hurdle."

I'm just not that popular here today.

An expensive reminder

A couple years ago, when we bought our house, our mortgage was underwritten by Countrywide. We went with them because they matched the best rate I found on the Internet.  While sitting in their office, signing all the paperwork, I remember reading one of their brochures where they said they kept 98% of their mortgages and that did impress me quite a bit.  The mortgage on our first house got transferred around between banks quite a bit, so I had to keep track of which company to send the next month's payment to.  Stability would be a good thing.

So, when the sub-prime market cratered, taking Countrywide along with it, I thought it was a typical market over-reaction. If they kept 98% of their mortgages, then obviously they would have taken care that the loans were sound. Care they wouldn't have taken if their plan to was to bundle the loans into securities and sell them off. So, I went out and bought some shares last week at the low prices on offer.

Yesterday's (Sunday's) New York Times had an article on Countrywide and how it, too, was caught up in the sub-prime mess. One in four of its sub-prime loans, the article says, is in default. And the article indicated that Countrywide sells a huge fraction of its loans too.  Oops. Had I misremembered something?

I had misremembered all right, but I was naive in not noticing the exact words used by the brochure. The crucial distinction seems to that Countrywide continues to service the loans that it packages and sells. It's responsible for collecting payments, and the brochure was simply saying that I wouldn't have to send payments to a different bank every few months. But Countrywide does sell many of the loans, thus divesting itself of some of the risk.  The investors who buy the loans pay Countrywide to take care of collecting the mortgage payments, so even though 98% of its customers wouldn't know it, Countrywide sells a majority of its loans. This of course means that they wouldn't be all that careful when making loans. Most of the time, it would be someone else's problem if the customer defaulted.

Another reminder, if I am ever in doubt again, that it is extremely hard to beat the market with publicly available information -- it's been factored in already. An expensive reminder.


Not only is the streak well and truly ended, last night we came in dead bottom.  Poor play, especially on defense sank us.

At what price cheap stuff?

Like every parent of young children, I have been reading with a sinking feeling in my stomach about the lead paint that was used by Mattel toys. Our kids do not have that many toys, but the ones they have they put in their mouths. A lot. And pretty much every toy is painted.

I doubt that the problem is limited to Mattel or to toys that were made in China. Even the toys that we bought at craft shops were probably painted or stained using cheap paints and chemicals, and cheap paint is likely to have been made in a developing country.  With little in the way of regulation of dangerous compounds.

Now comes an article by a pediatric cardiologist at U. Mass. saying that the industry essentially got politicians to torpedo stricter lead controls starting in the 1980s (The Reagan and the two Bush administrations are implicated) and that the 10 mcg/dl limit that is suggested as safe by the CDC would actually result in 7 lost IQ points.

At what price, cheap stuff? And at what price industry profits?

Finding overshooting tops

One of my colleagues has long wanted me to create an algorithm to find overshooting tops in satellite imagery. There were a couple of things holding me back -- one administrative and the other technical.

The first was a lack of funding to pursue that work. But all of a sudden, in the last six months or so, I have gotten funding (from NASA, NESDIS and HPCC) to work on satellite data. In the past few years, none of these guys would fund us. This year, they all did -- when it rains, it pours. Anyway, we have the funding, so I have the time. That's how science works. Administratively at least.

The second reason was techical. The first signature I tried to find on satellite data was v-shaped notches on infrared imagery which was at 4km resolution and came every half hour. The temporal and spatial resolution was too poor to do anything worthwhile (as a comparison, radar data is at 1-km resolution every 5 minutes). But recently, my colleague got his hands on 1-km visible data combined from the GOES east and west satellites at 1 minute intervals and suggested that I try to find overshooting tops which are indicative of strong updrafts which themselves are indicative of severe weather.

To find overshooting tops, I wrote an algorithm to look for areas with high spatial variance (taking to care to avoid using parts of the image that are unlikely to be clouds in the variance computation) and that was it! As it turned out, given 1km visible imagery, you don't even need a sequence for quality control (In many algorithms, one way to avoid lots of spurious detections is to correlate things across time).

In the image to the left, the red contours are drawn by the automated algorithm that results. Since the 1-minute temporal resolution is not required, and because 1km visible imagery is available during daylight hours in realtime, we should be able to run an overshooting tops algorithm in real-time. As the newpapers say, watch this space.

A tropical storm!

We had planned to go on Sunday to the Chickasaw Recreation Area, about an hour south of Norman. There are a few kid-sized waterfalls there, so it's a good place for a family day trip.

Unfortunately we woke up to rain in the morning. "Is the rain going to go away?," the wife asked, so I dutifully pulled up the radar pictures from the real-time WDSS-II website -- this is probably the first time that I've used our system to make a decision that affects me personally. Usually, I just use the Norman forecast office's website.

Imagine my surprise when the radar image looked like a hurricane. "Must be Erin," I thought. But it was still weird to see the eye of a tropical storm over central Oklahoma.

Anyway, the straight line of storms south of the eye would pass Sulphur by 10am but the satellite visible showed continued cloud cover. No rain, but overcast. I felt safe in announcing that we could go. And we could. It turned out to be a pleasant day. The kids had awesome fun. The two-year old wanted to know if she could "come back tomorrow".

As we were driving south, we encountered periodic bands of rains. I tried to explain to my father-in-law that this was like a cyclone. But he didn't realize that there was something strange in having a cyclone this far inland.

Off to school

It finally happened.  The 5-year old has been counting down the days to today. This morning he was off to school. He was absolutely excited and amazingly enough ready to go a full 30 minutes before the bus arrived (7.30 a.m ).

The 2-year old woke up as soon as he did and came to the street corner to send him off. She's been bearing the brunt of her brother's excitement. For the past few months, whenever they bicker, he'd start singing a ditty:
         S_'s not gonna go to school
         She's not even five
and reduce her to tears.  Today, she did fine for a while, even waving to him after he got on the bus but then she broke down.  "S. gone to school on the yellow school bus," she sobbed.  We consoled her saying that she'd be going to "2-year old" class soon.

The streak continues

Our severe weather products have been listed for the second year in the "Best of ... " series by the popular Google Earth Blog. The products themselves are available at
This post (from last year) describes what they found most interesting about our feed.

The streak ends

The streak had to end sometime. It did so yesterday. Every week since I took up bridge, I've been earning master points and am up to about 10 now. In yesterday's club game though, we placed in the bottom half and got zero points. Both partner and I were off our games. But better that we both had our off day on the same day, eh?

Young enough to be sisters

We were watching pictures from our Australian trip on the TV yesterday. Whenever A.'s picture came on the screen, the two-year-old would squeal "Amma!".  Then, turning to my sister-in-law, she'd translate "my Mommy".  (The two-year-old hasn't quite figured out who needs a translation from Tamil and who doesn't it, so she does it for everybody.) My sister-in-law would then say, "no ... it's MY sister".  This went on a couple of times.

A few minutes later, A's picture came up on the screen and the poor, confused two-year-old squealed "MY sister".

A bit too British?

We spent Saturday doing some hectic sight seeing in Sydney. The opera house, I'm sad to say, photographs much better than it really is. The harbor bridge is nice but it doesn't really add to the view. The harbor itself is quite lovely, and traversing it in a ferry is a wonderful experience. Manly beach is quite fun.

We took a tour of Government House, located in the Royal Botanic Gardens. Australia, to me, is an appealing mixture of American openness tied together with British scale. So, the people are friendly and obliging while the cars are small and the towns are built for walking. It was in the Government house that I saw the other side of the coin.

The Government house is the official house of the Governor of New South Wales, the state that Sydney is the capital of. Now, the Governor is not really elected (that would be the Chief Minister). The Governor is the representative of the Queen (of England). Bloody weird, if you ask me. And to make things weirder, there is very little that is Australian in that house. It's British style through out.

And incidentally, that's where we learned about the new fashion in Australian political life. The Governor doesn't actually live in that house. She has her own house and uses the British monstrosity as her official residence. But she's not the only one. Our hotel was in Kirribilli, a suburb right across the harbor from central Sydney and in Kirribilli is the house of John Howard, the Australian Prime Minister. Apparently, he decided to continue living in Sydney and to travel to Canberra for official functions? How strange is that? Imagine if George W. Bush had decided to stay in Crawford and visit the White House occasionally. That's pretty much what the Australian Prime Minister does.

Bill Bryson, in his extremely readable travelogue on Australia, remarks that John Howard's decision to continue living in Sydney caused an uproar. Mostly by residents of Canberra who were pissed that they hadn't thought of that first.


Friday, A. and I went with a couple of colleagues to Mossman Gorge, part of Daintree National Park. This is part of the Wet Tropics, another World Heritage site (besides the Great Barrier Reef). Queensland really does have an embarrassment of riches -- the tourist brochures make much of the "fact" that this is the only place with two so different World Heritage sites side-by-side. Although, the reef is about 30 miles east of the coast line and the wet tropics are 20 miles west. So, they're actually about 50 miles apart. But ... what is 50 miles considering that we traveled 8000 miles to get there?

You've probably heard the phrase "teeming with life". Believe me, you don't realize what that means until you've been to a tropical rainforest. There are trees with vines growing on them, and parasitic plants growing on the vines. The soil is too water logged? No problem -- the roots stick out of the ground so that they can pull in air.

The great barrier reef is truly great

Thursday is the day we went to the Great Barrier Reef. All the superlatives you've heard about the reef are true. Gorgeous green water, pristine white sand cays, an endless variety of sea creatures and corals in all sizes, shapes and colors and friendly Australian guides to it all. This is the trip of a lifetime.

The one unfortunate thing about our trip was that we happened to be the first diving group (there were four students to an instructor in the introductory dives). When you have the air tank and weights and are just figuring out to breath through a regulator, being shoved into 30-feet water is scary. So, we didn't end up doing much on the dive. As one of my friends, a diving instructor says, the introductory dives end up pushing it too quick. So, if you want to dive, learn to dive before you come.

But the snorkeling itself was great. Many corals are shallow, and the shallower the corals, the more vibrant the colors. And even in 4-feet waters, the variety of fish and sea critters is incredible. We even saw a blue starfish. There were whales a mile away, but by the time the boat got there, they were gone. So, we didn't see any whales or reef sharks.

The water was a clear, spectacular green. The sea was choppy yesterday, but visibility was still about 30 feet. There was an amazing variety of coral, and with four-feet corals near the cay, you could snorkel for a few minutes over the rocks watching the corals and fish and then simply stand in the sand for a while. Did I mention that this is the trip of a lifetime?

Attending my conference talk

Tuesday afternoon, I took a couple of hours off from the conference. A. and I caught the bus to Tjakupai, an aboriginal cultural center north of Cairns. There was one documentary of how the aboriginals got dispossessed of their land, but the other 2 hours of the show was surprisingly upbeat. There were didgeridoo demonstrations and we got to throw a boomerang and a spear. My boomerang went about 100 yards and came right back to me. I failed to catch it on its return though -- it was about 3 feet above my outstretched hand. Naturally, we bought a boomerang at the gift shop. Will need to try it out at Cambridge park when we get back to Norman.

On the way back, we got talking to a Canadian school teacher. She was in Australia for six weeks. It was nice, she said, to have a job with a long vacation.  Even nicer that a couple of friends from college had married Aussies.  When I mentioned that I was in Cairns for a conference and that the conference was going on at the time, she said that she hoped that when it came time for my talk, there would be people to listen. Spoken like an old-fashioned school marm.

It's a common misunderstanding that the main reason to attend scientific conferences is to speak -- although I usually speak at the conferences I attend. Instead, it's the networking that takes place at breaks, poster sessions and dinners.  The second reason, for me, is to be able to attend talks in fields I do not normally work in -- it's a good way to set up collaborations and steal ideas from other other fields.  This conference, I attended talks on precipitation estimation and forecast verification.  So, it wouldn't be much of a serves-me-right turnabout if no one turned out to hear me speak.

As it turned out however, my talk (on Wednesday) was quite well attended. It helped that it is part of a session on phased array radars, the hot new thing in weather radar. Secondly, there was no parallel session to siphon off attendees. Thirdly (and probably most important), Wednesday was the day of a conference outing and the banquet, so few people had day trips planned today.

Aussie directness

Cairns itself has very little going on. Everything is a drive away. Most touristy things are privately owned, and even the national parks and like have to be reached using tour services ostensibly to reduce the impact of unherded, isolated visitors. This means that there is heavy advertisement and commission-based sales of tours. Truth and moderation are a casualty of the whole setup. It's hard to get information on anything that doesn't involve a $100 tour.

Sunday, we went to a botanical gardens in the north of the city. The gardens has plants from tropical rainforests all over the world. Across from the gardens was a boardwalk that went into the rainforest. We started out at the top of the canopy with light-loving, tall trees. And then you walked into the understory with ferns and the like. And as we walked further and further, the soil got swampier and swampier. The trees and plants changed slowly, finally culminating in paper-bark trees and mangroves. And adjacent to the garden was a 300m hill that overlooked the airport. It took us 40 minutes to climb, but the views from the top of Mt. Whitfield was worth the effort. We could see the Pacific, the rainforest and planes taking off.

We found an elderly couple already at the bus stop to go back. "It's 13 degrees in Adelaide and raining," the lady told us. She was enjoying the heat, but it was still a bit much. "But you don't burn do you," she commented to my wife, "the sun doesn't affect dark skin as much."

Monday afternoon, we took off to beaches north of Cairns (Palm Cove, see picture on right). The water was cold (23C) and it was very, very windy but we did get into the water. Don't know how it'll be on Thursday when we go to the Great Barrier Reef. But however cold it is, we're going.

Coming back, we chanced on a shack that advertised itself as the "Outback Opal Mine". We got off the bus and went in. It was not a mine -- it was just a shop with a wall that was made to look like a mine. A scam. But the scam served its purpose because A. bought a few opal earrings to give as gifts. The blues were great and the milky white didn't look as good. "It'll look good on your skin," the saleswoman told my wife, "the white won't look good on a woman from England, but on your skin it'll look quite good." Apparently, Australians are a lot more casual when it comes to mentioning race -- I have a hard time picturing an American making the same comments.

The old fangled way of taking a photograph

Thursday evening (it's Saturday morning for me now: I'm blogging from Sydney airport, but it "feels" like it was last evening), A. and I took advantage of a 5-hour layover in Los Angeles to catch up with R., someone I who I went to elementary school with in Africa. R. brought her cousin along. A young, teenage cousin. We asked the cousin to take a picture of the three of us at the Tapas restaurant.

When I go on long trips, when I'm not sure when/if I'll be able to come across a battery charger or if the voltage/plugpoints will fit, I make sure to turn the LCD screen on the back of my digital camera off because it is a power hog. Besides, I've found that photographs taken at arms length have a greater tendency to shake -- if you squish your camera against your face, that's a
great way to stabilize it. So, I take most photographs the old-fashioned way: by looking through the view finder, not by composing it on a LCD screen.

Anyway, we asked the young girl to take a photograph and I told her to look through the viewfinder. She had no idea. She kept the camera at arms length and said she didn't see anything. I pointed out the eyehole to her, but she still couldn't get the idea that you could look through that peephole to take a picture.