First, a Compact Fluorescent Lightbulb. Seriously, these things are awesome. We had a very weak one in the dining room, part of a set of CFLs which were given to us by the property manager as part of an energy saving project. However, today I upgraded to a much larger lamp, a 150 watt equivalent CFL. This shot has totally been done before, but I wanted to play around with it. I used a small aperture and shot directly up at the ceiling fixture. I took this exposure almost directly after turning the light switch on, so the tube is still warming up.

Canon EOS 400D (Digital Rebel XTi), Canon EF 50mm f/1.4 @ f/16.0, 1/250, Aperture Priority program mode, ISO 200.

The second shot is of a lit candle. This was shot in darkness, with all room lights off. I put the camera on a tripod and focused on the candle with the lights on. Then I set the lens to manual focus and lit the candle, then turned off the lights. I used a cable release with the “Bulb” setting to achieve a 19 second exposure. During the exposure I blew towards the candle to create a wide soft look to the flame. The photo was later cropped to a vertical orientation featuring just the candle in Adobe Lightroom.

Canon EOS 400D (Digital Rebel XTi), Canon EF 50mm f/1.4 @ f/22, 19s, manual mode, ISO 100.

In the Volkswagen Golf, and many other cars, there is a light on the dash that illuminates when the cruise control is turned on. But the light reflects the state of the cruise control “master switch,” not whether or not the cruise control is actively controlling the throttle. Since the Golf is a drive-by-wire car, the pedal doesn’t move when it is manipulated by the cruise control. While the master control must be on to enable all cruise control features, it does not actually take control until you press set or resume.

On an aircraft, there would be one light for the master enable and a second light to indicate that the cruise control is actually active. Or, commonly, a light with an amber (armed) and green (active) indication. This is perfect for vehicle cruise control indicators as well. That way the driver always knows the state of the system with a quick glance. I don’t know why more manufacturers don’t do this - it merely requires using a dual color LED.

Recently I was looking up the EPA mileage figures for my 1992 Honda Accord 5-Speed and Abby’s 2003 Volkswagen Golf TDI 5-Speed. The fueleconomy.gov site is now listing the new revised MPG figures for new cars. But it looks like they have also adjusted older model years for effective comparison.

My Honda used to be listed as 22 MPG city, 29 MPG highway. My own driving has averaged around 27 MPG with around 25% city, 75% highway. On long trips, it has usually beaten the 29 MPG highway estimate with around 30 or even 31 MPG, despite highways speeds generally 70 and sometimes above. And that average of 27 MPG (since last October, most fill ups included) includes winter driving with shorter trips. And I usually accelerate swiftly frequently with high revs and full throttle (hey, full throttle in this vehicle isn’t that much power!). And, I have a toolbox in my trunk and radio gear, including an antenna which certainly creates drag. What am I doing right?

The EPA has revised the estimate for my Honda to 21 MPG city, 28 MPG highway. I don’t get this. I’m pushing the engine hard, with cold weather, high speeds, full throttle.. and I am rewarded by beating the EPA highway mileage by 2-3 MPG?! I can only imagine what kind of mileage I would be getting if I started driving like a grandma.

Abby’s Golf was originally listed as 44 MPG city, 49 MPG highway. The Golf has easily bested 50 MPG on our customary long trip from New Hampshire to Georgia. Last year the whole trip also included significant long distance commuting which pushed the total to near 4,000 miles. Despite winter tires, heavy loads, high speeds, air conditioning in the south, and cold temps up north. And that car doesn’t get driven gently either.

The EPA revised estimate for the Golf is… 35 MPG city, 44 MPG highway. This is around 6-8 MPG lower than what we typically get on the highway, even under demanding conditions. City is probably around 8-10 MPG lower than what we’ve observed. Is our experience unique? It boggles my mind that anyone could regularly drive the Golf in such a manner that it would get 44 MPG on the highway. I believe you could drive a long highway trip at 85-100 MPH and get 44 MPG.

I suppose I could see how someone could drive the Honda even harder than I do and get worse mileage. But that would certainly not be the way an average driver drives. I would say typically people are more gentle than I am. What is the point of these insanely low estimates released by the EPA?

I am curious about other people’s experiences, so please drop a comment if you keep track of mileage at all. It would be interesting to see how things compare.

These pictures of supercell thunderstorms from the cockpit of an airliner are incredible. Supercell thunderstorms are the most severe type of thunderstorm, and they usually feature high winds and hail. They are also likely to spawn tornadoes. Usually at the altitudes commercial jet airliners fly at (30,000 ft+) you are above any weather. But in those photos you can see the anvil of the thunderstorm extending far above the aircraft at 36,000 ft. Click on the photos for larger versions.

Weather is an amazing force. Whether it is sailing, flying, or hiking in the White Mountains, any outdoor activity requires respect for weather. We understand an awful lot about weather systems, but thunderstorm activity and tornadoes are still difficult to predict with certainty. In the storm mentioned above the water droplets in the storm cloud are actually dense enough that the aircraft weather radar can’t penetrate through to the other side. Our technology is defeated by water. Fortunately, aircraft still have the ability to give storms plenty of room and go around them, and our ability to predict the general characteristics of storms has made flying much safer.

I often hear people complain about delays in commercial aviation which are caused by things like thunderstorms over the Great Plains. The fact is, pilots would rather stay on the ground and wait until they have a clear way across instead of risking contact with powerful storms. When large scale storms cross the country they affect the many routes taken by aircraft all across the country in complex ways which limit capacity. It is better to wait on the ground than in the air. The amount of fuel burned while flying a holding pattern is immense.

In 1999 the US Food and Drug Administration changed the rules regulating “Direct to Consumer” or DTC advertising of prescription drugs. You are almost certainly familiar with these ads. It is almost possible to read a magazine or watch commercial TV without encountering them. There are still sizable restrictions on the content of these ads, including the mandatory description of side effects.

The United States has some of the most lax regulations on direct to consumer pharmaceutical marketing. In fact, most countries simply do not permit mass market advertising of prescription drugs. The reasoning for restricting direct to consumer advertising is clear from the ads we view today. They market prescription drugs as a panacea for life’s problems. By encouraging potential patients to “ask their doctor” about a particular medication they introduce bias and prejudice into medical diagnosis. Furthermore, frequently people end up taking medications they don’t really need, which drives up the cost of health care and medical insurance.

Between 1989 and 1999 spending on DTC pharmaceutical advertising increased from $12 million to $1.58 billion (source). By 2005, DTC spending increased to $4.2 billion. But you don’t even need to look at the dollar expenditures to know that prescription drug advertising is out of control - just flip on prime time TV. Complicating matters, many of the drugs advertised are psychiatric drugs, arguably some of the least well understood pharmaceuticals.

There is also a secondary affect from the direct to consumer advertising binge. It has driven which areas of health care drug companies are willing to pursue. Instead of targeting the most life threatening or dangerous diseases there is instead a huge interest in developing drugs which will be easy to market to consumers. This has also driven development of new derived from older drugs but with marginal improvement. Many people have questioned the need for Esomeprazole, extremely heavily marketed as Nexium. Esomeprazole is an updated version of Omeprazole (Prilosec). Both drugs were created by AstraZeneca Pharmaceuticals, but Omeprazole is now available in generic form. Despite the controversy surrounding its efficacy, in 2005 Nexium was the third best selling drug in the world.

There are many solutions to this. Generally I tend to prefer avoiding government regulation when possible. But this is an example where it is very important to restrict commercial activity in order to ensure it doesn’t affect the safety of health care. I think at this point there is at least a need to return to the more restrictive rules in place before 1999. Going further, the US could also choose to align themselves with the EU and ban direct to consumer advertising. A good compromise solution might be to restrict television advertising but allow print advertising, which currently provides significantly more information about the side effects and mechanism of the drug.

Many people wonder whether they really need to use premium gasoline. The truth is it depends on your vehicle. However, most modern vehicles can take regular (although some may benefit from premium).

The octane of motor gasoline refers to its resistance to detonation - spontaneous ignition of the fuel without the spark from the spark plug. This results in a “knocking” or “pinging” sound and will result in engine damage. Engines which have higher compression typically require higher octane fuel. The compression ratio refers to the amount the fuel/air mixture is compressed by on each stroke of the piston. More compression will obtain higher performance and efficiency from the engine, but will require higher octane fuel. When the pressure in the cylinder increases during compression the air/fuel mixture heats up and will spontaneously ignite unless the fuel has sufficient octane rating.

Turbocharging and supercharging also affect the octane requirement. When you force additional air into the engine using a turbocharger or supercharger you increase the maximum cylinder pressures and thus the heat. This means that the effective compression ratio is higher. Again, there is more performance and efficiency, but a higher octane is required.

Modern fuel injected vehicles typically have a “knock sensor” which can detect engine knock if it occurs. The knock sensor is simply a microphone positioned in the engine block. If the engine computer detects knocking, it acts to slightly retard (slow) the ignition timing. This helps reduce the knocking, at a slight performance cost. Alternatively, turbocharged vehicles may simply open the wastegate or reduce boost, which will again stop the knocking at a cost to performance.

The upshot to this is that most modern vehicles which “recommend” premium fuel in the owner’s manual can be run perfectly well on regular gasoline and the engine computer will adjust automatically. The key distinction to look for is “recommended” as opposed to “required.” If the owner’s manual says “required” you must use premium fuel to prevent knocking and engine damage. On antique or older cars you should use whatever grade is necessary to prevent knocking.

There is an additional difference sometimes present in premium gasoline. Premium gas sometimes contains more additives designed to keep the fuel injection system clean. Generally the additives found in regular are sufficient, unless you are having issues with rough running. You can always add concentrated fuel system cleaner (Chevron Techron is well known as being a good product) if you need it.

Bruce Schneier says that expertise makes the difference between the scared citizen reports and the useful reports. I agree. We need to weigh the response accordingly when receiving responses. And, instead of deploying security personnel who confiscate harmless materials based on stupid standards, we need to employ fewer people with more training.

A company named EEStor made big news recently with the announcement of a new ultracapacitor they plan to use in electric cars. The company claims the car will run for 500 miles on around $9 worth of electricity, and will charge in five minutes. There are a few problems with this. The first is that $9 is an absolutely meaningless number from a technical standpoint. Electric rates vary significantly between different regions in the US. However, a conservative assumption is that the company chose the lowest rates found in the US, 5.81 cents per kilowatt-hour (Source: DOE). $9 worth of electrity at $0.0581/Kwh is around 155 kilowatt-hours!

A kilowatt hour represents a quantity of energy equal to a 1000 watts in one hour. To transfer 155 kilowatt-hours worth of energy in 5 minutes would necessitate power consumption of 1.86 megawatts. 1.86 megawatts is a lot of power. A normal household outlet is 120 volts. At this voltage, a power of 1.86 megawatts would represent a current of around 15,500 amps. To put this into perspective, a normal household circuit is between 15 and 30 amps. Even at higher voltage the amp draw is incredibly high. The wiring required to support such an incredible current demand safely would be immense. While the promise is good, the numbers just don’t add up.

In CS520 today I found out that my assignment (mentioned previously) was actually due not today but on Tuesday. So, there were still questions from other students regarding help with the assignment. One student was storing the graph data as a single array containing the upper right triangle of the matrix, read out from left to right one row after another. He was trying to figure out how to index into this array to get a particular item without using a for loop. It is, of course, possible to do this. However, several people in the class insisted that it could not be done.

For a graph with n vertices, this data structure has n - 1 data points in the first row, n - 2 in the second, and so on. The first step in indexing into the array is to figure out where the row you want starts. You could do this using a for loop which sums up a counter with (n - 1) + (n - 2) + …, but this is very inefficient - the algorithm is O(n) versus a possible O(1) implementation. The hint is of course the summing you need to do.

Gauss is famous for figuring out a shortcut way to sum all the numbers between one and 100 in elementary school. What Gauss figured out is that any time you sum a series of numbers between 1 and n the answer is n(n+1)/2. You can use this fact to figure out the indexing problem. First, separate out the sum of i:

The sum of (n - 1) over i from 1 to n is just n(n-1). We can use the expansion of the sum of i to determine a result:

Not only is it possible without a for loop, it is a very clean result! Of course, our job isn’t finished - we still need to add an offset for the position within the row. This is left as an exercise (it isn’t hard to do. Just think of the relationship between the number of vertices, row number, and the number of items in the row).

After class I was waiting around because I planned to go to the UNH ACM chapter’s free pizza/learn about Linux event. The instructor asked me about some of the other caching things I’d implemented and suggested that the results of searching the graph are also eligible for caching, a possibility I hadn’t considered. It ends up being a significantly more complicated problem, because if you want to keep track of paths discovered between nodes in a reusable fashion. It also led to him asking me if I knew about UROP. While I’d love to do UROP I’m not sure how well that can coincide with trying to work part time.

The UNH ACM chapter event was also fun and although I certainly didn’t learn anything new about Linux there was a good turnout of people who did and I got to meet some new folks.. and re-meet some people who’ve previously been in my classes. It turns out most of them are seniors, so they are looking for not-seniors to get involved as well. Yet another thing to eat my time!

So, I am now a Computer Science major! And, my schedule for fall is finalized:

• MATH 531: Mathematical Proof. With Rita Hibschweiler, whom I had for Calculus I some time ago. I’m looking forward to this, I think it will be fun.
• CS 520: Assembly Language and Machine Architecture. This will be similar to ECE612/562 and ECE543. But CS majors are required to take all three courses so now I will be learning it from a different perspective.
• CS 671: Programming Languages. This will cover the ML Programming Language and some advanced Java topics. ML is a functional programming language, which will be neat because I don’t have much experience with that paradigm. I wish we were covering another language besides Java in the second half, however.
• PHIL 447: Computer Power and Human Reasoning. I like the professor for this class and I think it will be a lot of fun. It’ll be nice to be taking a non-technology class again.

My laptop, crow, was recently RMA’d under its very worthwhile extended warranty. Unfortunately it experienced a failure to boot at the worst possible time this semester. I had also mentioned the existance of a small scratch on the screen which I never did anything about, which technically should have been reported immediately reported if I wanted to have it dealt with under warranty. The tech support person said they would look at it and replace it if it looked like it was not a wear and tear issue.

My laptop has now been returned to me, with a new mainboard, processor (soldered to mainboard), LCD panel, and LCD frame. Basically, most of the parts have been replaced. I am overjoyed that they replaced the LCD. And, the thing that really made my day was that they did not reformat my hard drive. Linux is still installed and completely usable. This makes me very, very happy.

I often read on forums somebody saying “Well, I don’t need snow tires because I have ABS.” Or worse, “I don’t need snow tires because I have AWD.” The problem with the latter statement is obvious (AWD does not help you stop or turn) but the problem with the former is less obvious. ABS actually increases the need for good rubber between the car and the road.

Having good tires is the single biggest factor in winter driving. This doesn’t just mean having snow tires. Having bald or worn tires is worse than having all seasons. Even if you do not live in an area where it snows enough to consider purchasing snow tires, it is very important to check your tire tread depth using the penny test. If you have insufficient treadlife remaining, replace your tires before it starts snowing.

But why does ABS increase the need for good tires? ABS works using a technique called “cadence braking” to prevent the wheels from skidding during braking. When the ABS controller detects a wheel has stopped spinning (locked) it releases the brake pressure on that wheel until it spins again. It then increases the pressure until it stops, and so on. More sophisticated ABS systems can do this quite fast, and can usually shorten braking distance on dry pavement compared to a human executing the cadence braking maneuver, and somtimes even a skilled driver executing a threshold braking maneuver. In any case, the tire’s grip still matters because a stickier tire will grip longer before the wheel locks requiring less ABS action.

But we aren’t talking about dry pavement, we’re talking about winter driving on snow and ice. On snow and ice ABS drastically increases stopping distances. In snow, when the wheels lock a wedge of snow builds up in front of the tire causing a significant retarding effect. But ABS destroys this effect in its attempt to keep the wheels rolling. As a result, the ABS controller spends much of the time with the brakes released and it takes longer to stop. On ice, the wheels lock up so readily that the ABS hardly applies the brakes at all and stopping distances are nearly doubled compared to a locked wheels slide. The issues seen with snow are also seen in loose gravel and sand.

Modern ABS systems are significantly better at handling these situations, but are still subject to drastically increased stopping distances. The solution to this is twofold. The first factor is to make sure you are using good tires. As stated above, good tires mean there will be more braking ability before the wheels lock and the ABS system intervenes. The second factor is to be aware that the purpose of ABS is to allow the drive to retain some steering ability during braking and not to improve stopping distances.

There is a sophisticated solution to the problem of having to make an emergency stop where the ABS effect is detrimental. You can deliberately skid the car 90 degrees perpendicular to the original direction of motion. The car will continue to skid forward in the same direction, but all four wheels will be sliding accumulating the “wedge” and will enable a quicker stop. However, this is a difficult maneuver to get right and requires enough parking lot practice to make it automatic before using it in an emergency. In the meantime, just get some good tires and remember that ABS doesn’t help you stop.

In my computer organization class, our labs involve programming a Motorola M68HC12 microcontroller. While doing my lab work today, I discovered that the CPU12’s instruction set contains a SEX instruction. The mnemonic is short for “Sign Extend into 16-bit register.” Maybe this is why my professor last semester was so obsessed with sign extension?

The SEX instruction is pretty gratuitous. It is simply an alternate mnemonic for a the register transfer instruction. However, who doesn’t like a little gratuitous SEX?

After two years with my trusty LG VX6000, I have upgraded to a new and shiny Motorola E815 for free. Although my new phone does not support analog (the VX6000 didn’t either), it does support EV-DO. EV-DO is the CDMA network’s next generation data, capable of near-broadband speeds over the cellular network. However, this service isn’t available everywhere and is restricted to metro areas. I was surprised to see that my phone was reporting an EV-DO signal right near here in Newfields, NH and Stratham, NH. Does this mean more data options are coming soon? The high speed data service isn’t very useful to me right now, but if I was working on the road like my Microtime Computers field service job it would sure be nice.

After years of having no cell phone towers at all, Verizon is finally going to build a tower in Newmarket. The tower is muchly needed. Currently the Verizon signal I receive is from a Durham tower, and while it works satisfactorily, signal strength is low. Downtown Newmarket is covered by no providers and coverage along Route 108 is very spotty. From the position, it looks like this tower has been positioned to service downtown Newmarket, Route 108 in Durham, and fill in service in downtown Durham.

The funniest thing about the article above is the NIMBYs. In addition to the usual property values complaint, the woman quoted in the article actually believes the existance of the cell tower is going to put the local daycare out of business. I’m serious! If you ask me, improving the spotty service in the town is likely to improve property values. I know if I tried to rent one of the really nice places downtown and found out my cellphone was useless there I’d have to seriously rethink things.

MSNBC has a fascinating set of articles about the future of evolution. I think the article about diet is especially interesting. I’ve always seen lack of regular physical activity to be a major factor in our “obesity epidemic.” The difference between lean meats from hunted game and meat from lazy domesticated animals did not occur to me. Our hunter-gatherer ancestors also spend a full day’s work being active. This is something few Americans do these days.

The UK Guardian has an article about some of the horendous working conditions at Nike’s factories:

In more than half of Nike’s factories, the report said, employees worked more than 60 hours a day.

Somebody call the NGOs!@ Screw it, somebody call Stephen Hawking! They must have some sort of time portal there! Thus, this weblog entry is unique in receiving the humour, scitech, and politics categories. (If they’ve corrected the error, view a screen shot.)

All joking aside, this is probably one of the best examples of what can go wrong with globalization. Nike has been known as a sweatshop company for years, yet they never seem to care. Why? Because customers continue to purchase Nike’s products, even when they know the truth about factory conditions.

The House wants to extend daylight savings time by two months. Personally, I hate daylight savings time. I like my noon when the sun is overhead. I understand the “energy saving” rationale, though I’m not quite sure I agree with it. Don’t people turn on their A/C in the summer when they get home? According to Wikipedia, DST is particularly unpopular in agriculture. This is funny, because DST was always been explained to me as something created to benefit farmers. I guess that was an urban legend. Several US states don’t even practice daylight savings time, most of them middle states where agriculture dominates.

Dance Dance Revolution is video game which tests a player’s ability to dance out patterns on a touch sensitive map. I’ve played it once or twice; it is a surprisingly difficult task both physically and mentally. USA Today has an article about a pilot program using Dance Dance Revolution to improve the physical fitness of obese children. This is an excellent idea. Research has shown that even short periods of physical activity each day improve fitness and metabolism. By using video games to get kids interested in being active this program eliminates the classic barrier to beginning an exercise program: it doesn’t get easy until you’ve been doing it for a while.

Find the values of λ for which y = e^λx satisifies the equation y + y’ = y”;.