One of the biggest issues with wind and solar is that they are intermittent, and so either need storage or grid-tie to work. There really is no good storage, and generally storage-based systems are highly wasteful, throwing away most of the power you generate because you want to keep the storage near full. Grid-tie is the only green choice, but it’s expensive and requires expensive inverters and permits and more.
One solution to this to find work for your renewable energy source to do that fits well with its intermittent nature. Something that will take all the power you generate, but not mind if it comes and goes. Such loads are hard to find. One potential example is pumping water to filter a swimming pool. Its recommended to flow twice the volume of your pool every day in summer, which means around 10kwh of electricity with typical systems. Most people filter their pool using the same pump they use for vacuuming and pool maintenance, which is actually way more powerful than you need for filtering. They offer variable speed pumps, which use a low-power efficient speed for filtering and a high-power speed for vacuum and manual operations, and claim they save a lot.
For those who have a pool, the pump is using as much electricity as all their other appliances in some cases, and so it’s a win to make that greener. Unlike those appliances, the pool water can be filtered any time, as electricity is available, though you can’t let the pool go unfiltered for days, so it’s not perfect. For people who have time-of-use metering, they are wise if they only filter at night, and many do that.
The trick to perfect use of solar for pool pumping would be a smart, multi-speed pump able to run on both the DC from solar panels and the grid power. It would need to do the following:
- When there is power from the solar panel, run as fast as you can on that power, filtering.
- When you need high flow, switch to (or combine with) grid power for full power.
- Track the amount of water filtered, as well as temperature, and when the sun did not provide enough power, run the pump at night off grid power to make up the difference.
- For extra credit, have a sensor that detects how clear the water is, and adjust grid usage based on that, rather than just weather.
This system would make use of all the power from the panels. As a plus, you need more filtering in summer than you do in winter, which matches what panels do. However, you must not oversize your panels. They can’t be bigger than you need to do all your winter filtering on a series of sunny winter’s days, or you will be wasting their power then.
Key to this plan is that it’s easy to install. Put in the new pump and wire it up to panels. No inverters or electricians and perhaps not even any permits. It doesn’t feed power back to the grid or the house. This is key because panels are now getting very cheap (less than a dollar per watt) and as such installs and permits and other gear are more expensive than the panels.
There are some pool pumps with brushless DC motors sold for solar use. They are expensive and don’t do the smart tricks above, in particular using the grid to take up the slack. They depend instead on overprovisioned solar, or solar systems powering more than a
For $700 you can also buy a floating solar pool filter. This is a nice trick because it’s self-contained, though it’s a rather large thing to float in your pool. It can’t handle the whole filtering load —in fact it only handles about 25% of the load of a typical pool and uses cartridge filters. As such, you still run the regular pump and filter on some schedule, you just run it a bit less.
I noted above that you can get variable speed pumps, and that these, it is claimed, us as little as 1/5th the energy of the full speed pumps for filtering. They cost 2-3x as much as basic one speed pumps, and as a result are not very common. This bodes poorly for the solar proposal here, because if customers aren’t willing to do the up-front investment to save energy for these pumps, few would do the added task of putting up a solar panel and plugging it into such a pump. Comparatively few, that is — solar nerds would love to do it.
As always, the best place to deploy panels to do this would be the sunny, coal-oriented regions like Arizona and New Mexico, where it turns out pools are pretty popular. Once again, the math says that if your goal is to use your money and time to make the world greener, it would be far better to get people in those places to install a system like this on their pools than for you to put panels on your house in California for anything. Putting panels up in California is something you do to feel good.
Another interesting alternative is wind. Pumping water with wind is perhaps the oldest wind technology out there. In this case, you might even be able to be like an old windmill, and be mechanical, by having the turbine drive a flexible shaft down to the ground to run the pump. Presumably some clever transmission would be needed to maintain filter pressure properly at all windspeeds. You could also do traditional electrical generation from the wind and power a pump like the one above.
Wind has its positives and negatives. Unlike solar, it does not have the natural higher capacity in the summer. It can be much more intermittent. Solar panels still do around 30% to 50% of their rated power on ordinary cloudy days (though this is quite variable based on the panels and local weather patterns) so there is pumping every day. Wind in most places comes and goes. At my house, the winds are high today but it would not generally be suitable as we go weeks without much wind. Wind also prefers a tower near the pool, which has many issues.
A potpourri of claims about HealthCare.gov maintains that the site was developed on a no-bid contract at a cost overrun of $634 million by a Canadian company that donated $47 million to the Obama campaign and employs Michelle Obama's classmate as a top executive.
The past few weeks have been rife with governments deciding to throw support behind robocars.
I wrote earlier about the plan for pods in Milton Keynes, NW of London. The UK has also endowed a a £10m prize fund to build vehicles and for a town to adapt to them. This will be managed in part by the Oxford team which has built a self-driving Wildcat and Nissan LEAF.
In Michigan, they have been working on a new robocar law that may be the next one, and the University of Michigan has a plan to put a fleet of cars out by 2021. Ann Arbor is the site of the ITS V2V testbed, which will probably slow this effort down, but Michigan is keen on not having the auto industry taken away from it.
Volvo, while now a Chinese company, has had many efforts, including their Sartre convoy experiments. Now they have declared that they will have 100 cars on the road in Gothenberg in 2017. They will also build parking systems.
In spite of all this, Toyota recently declared it is only building vehicles for research purposes, and has no desire to market such cars. Toyota had been a leader among the Japanese companies (until Nissan took over that role by building a research lab in silicon valley) but it’s surprising to see them drop out. Of course I predict they will regret that.
Amazon drone delivery
The big news this weekend was the announcement that Amazon.com wants to do drone delivery, accompanied with a concept video. This got everybody buzzing. I was interviewed for stories by the Washington Post and Wall Street Journal (paywall) as well as the New York Times (pending) because of my prior writings on deliverbots.
Some of you may remember I post I did early last year on drone defibrillator delivery and the efforts of our students at Singularity University to build Matternet for drone delivery in the developing world.
Drone delivery is interesting, though its big value will be in lightweight, urgent items like medicines. Ground vehicles will still win for cost and efficiency for most items. However, the drones can be much faster, and have options like delivering to places ground vehicles can’t reach — like your roof or your backyard. Deliverbots must get safe and legal on busy streets, drones have to figure out how to not hit one another (or people on the ground) in crowded airspace. The LIDARS that make ground vehicles practical have enough range for ground travel but poor range as flying sensors. Radar is good in the air but can have interference problems.
Getting a drone to land at any given address is a hard problem. There are trees, overhead wires, wind gusts and strange geometries. I suspect drone delivery will work best if the drop location has already been scanned and mapped. However, if there is a decent clearing, I could see it working by having the recipient put down a special marker (like a QR code) on the ground. GPS is not accurate enough to fly with but camera could pull out special markers.
One great marker would be your cell phone. Either with its “flash” LED pointed up and pulsing, or its screen, if the screen is bright enough. Go outside, put your phone down, have it guide the drone partway in with radio and GPS, and then have the drone’s camera follow the flashing light. If phones had better raw GPS access (they don’t — not yet) they could also provide differential GPS information to a drone to guide it in.
This works because with robot delivery, you never need to deliver to an address — you deliver to a person. Wherever that person is, or at least never when the person isn’t there, unless you want to. A robot delivery service will wait for a signal that you are home or one the way before delivering to your home, but might also deliver to you in whatever parking lot you are in, or your office. The robot won’t release the cargo unless it gets the ACK from your phone as you “sign” for it.
Multi-copter drones today don’t have a lot of capacity and range, but it’s improving. Liquid fuels for larger drones might help boost that. Fixed wing drones have much more capacity, but they need runways (or a skilled launcher) to take off. Some fixed-wing drones can land vertically if they have motors powerful enough to lower them down tail first though they tend to need something suitable to land on in such cases.
Robot delivery should make existing retailers, even big box ones like WalMart, scared of online retailers like Amazon. While a drone won’t replace WalMart on a trip where you plan to fill your shopping cart, it might well be very suitable for the things you buy from Walgreens.
Two years ago I gave a lecture and posted
about bitcoin. Of course what I didn't do was buy a bitcoin whose value back then was about $3 and today runs in the $1000 range.
Bitcoins have received quite a bit of press, particularly with the FBI shutting down Silk Road
, the drug trafficking site which used bitcoins for their transactions. Then people realized that bitcoins are starting to become a real currency, with a market cap of about US$11 billion not far now from the money supply of the Costa Rica Colones (US$13 billion). Now governments are deciding on how to deal with bitcoins as a currency, one which they really can't regulate or control.
The Economist has one of the better articles
on Bitcoins, talking about some of the technical issues involved.
The Bitcoin system is designed to cope with the fact that improvements in computer hardware make it cheaper and faster to perform the mathematical operations, known as hashes, involved in mining. Every 2,016 blocks, or roughly every two weeks, the system calculates how long it would take for blocks to be created at precisely 10-minute intervals, and resets a difficulty factor in the calculation accordingly. As equipment gets faster, in short, mining gets harder. But faster equipment is constantly coming online, reducing the potential rewards for other miners unless they, too, buy more kit. Miners have formed groups that pool processing power and parcel out the ensuing rewards. Once done with ordinary computers, mining shifted to graphics-processing units, which can perform some calculations more efficiently. Miners then moved on to flexible chips that can be configured for particular tasks, called field-programmable gate arrays. In the past year, bespoke chips called ASICs (application-specific integrated circuits) have appeared on the scene.
Then there was the paper
Dorit Ron and Adi Shamir wrote that explored the bitcoin transaction graph and suggested a (now supposedly debunked
) connection between the mysterious creator of bitcoins, "Santoshi Nakamoto", and Ross William Ulbricht aka Dread Pirate Roberts, the founder of Silk Road.
Bitcoins even make it to my Thanksgiving table. My brother thought they were a scam even though I pointed out the systems has no scammers. He remains unconvinced though he invests heavily in gold, which has the same property of the value mostly being there because people believe it has value.
I taught a lecture on bitcoins again in my intro theory course. We all generally agreed that a few years from now we'll all remember the days when bitcoins were worth $1000. Not sure we'll remember those days because bitcoins will be worth millions or because they'll be worth pennies.
The consulting company that Alicia worked for, NewSoft Associates, was in the intelligence business. Their work involved digging through data produced using technology that was years and decades old,...
As the world marked the 50th anniversary of the JFK assassination, I have to confess … no, no, not that I was in on the plot. I wasn’t even born then, silly. I have to confess that, in between struggling to make a paper deadline, attending a workshop in Princeton, celebrating Thanksgivukkah, teaching Lily how to pat her head and clap her hands, and not blogging, I also started dipping, for the first time in my life, into a tiny fraction of the vast literature about the JFK assassination. The trigger (so to speak) for me was this article by David Talbot, the founder of Salon.com. I figured, if the founder of Salon is a JFK conspiracy buff—if, for crying out loud, my skeptical heroes Bertrand Russell and Carl Sagan were both JFK conspiracy buffs—then maybe it’s at least worth familiarizing myself with the basic facts and arguments.
So, what happened when I did? Were the scales peeled from my eyes?
In a sense, yes, they were. Given how much has been written about this subject, and how many intelligent people take seriously the possibility of a conspiracy, I was shocked by how compelling I found the evidence to be that there were exactly three shots, all fired by Lee Harvey Oswald with a Carcano rifle from the sixth floor of the Texas School Book Depository, just as the Warren Commission said in 1964. And as for Oswald’s motives, I think I understand them as well and as poorly as I understand the motives of the people who send me ramblings every week about P vs. NP and the secrets of the universe.
Before I started reading, if someone forced me to guess, maybe I would’ve assigned a ~10% probability to some sort of conspiracy. Now, though, I’d place the JFK conspiracy hypothesis firmly in Moon-landings-were-faked, Twin-Towers-collapsed-from-the-inside territory. Or to put it differently, “Oswald as lone, crazed assassin” has been added to my large class of “sanity-complete” propositions: propositions defined by the property that if I doubt any one of them, then there’s scarcely any part of the historical record that I shouldn’t doubt. (And while one can’t exclude the possibility that Oswald confided in someone else before the act—his wife or a friend, for example—and that other person kept it a secret for 50 years, what’s known about Oswald strongly suggests that he didn’t.)
So, what convinced me? In this post, I’ll give twenty reasons for believing that Oswald acted alone. Notably, my reasons will have less to do with the minutiae of bullet angles and autopsy reports, than with general principles for deciding what’s true and what isn’t. Of course, part of the reason for this focus is that the minutiae are debated in unbelievable detail elsewhere, and I have nothing further to contribute to those debates. But another reason is that I’m skeptical that anyone actually comes to believe the JFK conspiracy hypothesis because they don’t see how the second bullet came in at the appropriate angle to pass through JFK’s neck and shoulder and then hit Governor Connally. Clear up some technical point (or ten or fifty of them)—as has been done over and over—and the believers will simply claim that the data you used was altered by the CIA, or they’ll switch to other “anomalies” without batting an eye. Instead, people start with certain general beliefs about how the world works, “who’s really in charge,” what sorts of explanations to look for, etc., and then use their general beliefs to decide which claims to accept about JFK’s head wounds or the foliage in Dealey Plaza—not vice versa. That being so, one might as well just discuss the general beliefs from the outset. So without further ado, here are my twenty reasons:
1. Conspiracy theorizing represents a known bug in the human nervous system. Given that, I think our prior should be overwhelmingly against anything that even looks like a conspiracy theory. (This is not to say conspiracies never happen. Of course they do: Watergate, the Tobacco Institute, and the Nazi Final Solution were three well-known examples. But the difference between conspiracy theorists’ fantasies and actual known conspiracies is this: in a conspiracy theory, some powerful organization’s public face hides a dark and terrible secret; its true mission is the opposite of its stated one. By contrast, in every real conspiracy I can think of, the facade was already 90% as terrible as the reality! And the “dark secret” was that the organization was doing precisely what you’d expect it to do, if its members genuinely held the beliefs that they claimed to hold.)
2. The shooting of Oswald by Jack Ruby created the perfect conditions for conspiracy theorizing to fester. Conditioned on that happening, it would be astonishing if a conspiracy industry hadn’t arisen, with its hundreds of books and labyrinthine arguments, even under the assumption that Oswald and Ruby both really acted alone.
3. Other high-profile assassinations to which we might compare this one—for example, those of Lincoln, Garfield, McKinley, RFK, Martin Luther King Jr., Gandhi, Yitzchak Rabin…—appear to have been the work of “lone nuts,” or at most “conspiracies” of small numbers of lowlifes. So why not this one?
4. Oswald seems to have perfectly fit the profile of a psychopathic killer (see, for example, Case Closed by Gerald Posner). From very early in his life, Oswald exhibited grandiosity, resentment, lack of remorse, doctrinaire ideological fixations, and obsession with how he’d be remembered by history.
5. A half-century of investigation has failed to link any individual besides Oswald to the crime. Conspiracy theorists love to throw around large, complicated entities like the CIA or the Mafia as potential “conspirators”—but in the rare cases when they’ve tried to go further, and implicate an actual human being other than Oswald or Ruby (or distant power figures like LBJ), the results have been pathetic and tragic.
6. Oswald had previously tried to assassinate General Walker—a fact that was confirmed by his widow Marina Oswald, but that, incredibly, is barely even discussed in the reams of conspiracy literature.
7. There’s clear evidence that Oswald murdered Officer Tippit an hour after shooting JFK—a fact that seems perfectly consistent with the state of mind of someone who’d just murdered the President, but that, again, seems to get remarkably little discussion in the conspiracy literature.
8. Besides being a violent nut, Oswald was also a known pathological liar. He lied on his employment applications, he lied about having established a thriving New Orleans branch of Fair Play for Cuba, he lied and lied and lied. Because of this tendency—as well as his persecution complex—Oswald’s loud protestations after his arrest that he was just a “patsy” count for almost nothing.
9. According to police accounts, Oswald acted snide and proud of himself after being taken into custody: for example, when asked whether he had killed the President, he replied “you find out for yourself.” He certainly didn’t act like an innocent “patsy” arrested on such a grave charge would plausibly act.
10. Almost all JFK conspiracy theories must be false, simply because they’re mutually inconsistent. Once you realize that, and start judging the competing conspiracy theories by the standards you’d have to judge them by if at most one could be true, enlightenment may dawn as you find there’s nothing in the way of just rejecting all of them. (Of course, some people have gone through an analogous process with religions.)
11. The case for Oswald as lone assassin seems to become stronger, the more you focus on the physical evidence and stuff that happened right around the time and place of the event. To an astonishing degree, the case for a conspiracy seems to rely on verbal testimony years or decades afterward—often by people who are known confabulators, who were nowhere near Dealey Plaza at the time, who have financial or revenge reasons to invent stories, and who “remembered” seeing Oswald and Ruby with CIA agents, etc. only under drugs or hypnosis. This is precisely the pattern we would expect if conspiracy theorizing reflected the reality of the human nervous system rather than the reality of the assassination.
12. If the conspiracy is so powerful, why didn’t it do something more impressive than just assassinate JFK? Why didn’t it rig the election to prevent JFK from becoming President in the first place? (In math, very often the way you discover a bug in your argument is by realizing that the argument gives you more than you originally intended—vastly, implausibly more. Yet every pro-conspiracy argument I’ve read seems to suffer from the same problem. For example, after successfully killing JFK, did the conspiracy simply disband? Or did it go on to mastermind other assassinations? If it didn’t, why not? Isn’t pulling the puppet-strings of the world sort of an ongoing proposition? What, if any, are the limits to this conspiracy’s power?)
13. Pretty much all the conspiracy writers I encountered exude total, 100% confidence, not only in the existence of additional shooters, but in the guilt of their favored villains (they might profess ignorance, but then in the very next sentence they’d talk about how JFK’s murder was “a triumph for the national security establishment”). For me, their confidence had the effect of weakening my own confidence in their intellectual honesty, and in any aspects of their arguments that I had to take on faith. The conspiracy camp would of course reply that the “Oswald acted alone” camp also exudes too much confidence in its position. But the two cases are not symmetric: for one thing, because there are so many different conspiracy theories, but only one Oswald. If I were a conspiracy believer I’d be racked with doubts, if nothing else then about whether my conspiracy was the right one.
14. Every conspiracy theory I’ve encountered seems to require “uncontrolled growth” in size and complexity: that is, the numbers of additional shooters, alterations of medical records, murders of inconvenient witnesses, coverups, coverups of the coverups, etc. that need to be postulated all seem to multiply without bound. To some conspiracy believers, this uncontrolled growth might actually be a feature: the more nefarious and far-reaching the conspiracy’s tentacles, the better. It should go without saying that I regard it as a bug.
15. JFK was not a liberal Messiah. He moved slowly on civil rights for fear of a conservative backlash, invested heavily in building nukes, signed off on the botched plans to kill Fidel Castro, and helped lay the groundwork for the US’s later involvement in Vietnam. Yes, it’s possible that he would’ve made wiser decisions about Vietnam than LBJ ended up making; that’s part of what makes his assassination (like RFK’s later assassination) a tragedy. But many conspiracy theorists’ view of JFK as an implacable enemy of the military-industrial complex is preposterous.
16. By the same token, LBJ was not exactly a right-wing conspirator’s dream candidate. He was, if anything, more aggressive on poverty and civil rights than JFK was. And even if he did end up being better for certain military contractors, that’s not something that would’ve been easy to predict in 1963, when the US’s involvement in Vietnam had barely started.
17. Lots of politically-powerful figures have gone on the record as believers in a conspiracy, including John Kerry, numerous members of Congress, and even frequently-accused conspirator LBJ himself. Some people would say that this lends credibility to the conspiracy cause. To me, however, it indicates just the opposite: that there’s no secret cabal running the world, and that those in power are just as prone to bugs in the human nervous system as anyone else is.
18. As far as I can tell, the conspiracy theorists are absolutely correct that JFK’s security in Dallas was unbelievably poor; that the Warren Commission was as interested in reassuring the nation and preventing a war with the USSR or Cuba as it was in reaching the truth (the fact that it did reach the truth is almost incidental); and that agencies like the CIA and FBI kept records related to the assassination classified for way longer than there was any legitimate reason to (though note that most records finally were declassified in the 1990s, and they provided zero evidence for any conspiracy). As you might guess, I ascribe all of these things to bureaucratic incompetence rather than to conspiratorial ultra-competence. But once again, these government screwups help us understand how so many intelligent people could come to believe in a conspiracy even in the total absence of one.
19. In the context of the time, the belief that JFK was killed by a conspiracy filled a particular need: namely, the need to believe that the confusing, turbulent events of the 1960s had an understandable guiding motive behind them, and that a great man like JFK could only be brought down by an equally-great evil, rather than by a chronically-unemployed loser who happened to see on a map that JFK’s motorcade would be passing by his workplace. Ironically, I think that Roger Ebert got it exactly right when he praised Oliver Stone’s JFK movie for its “emotional truth.” In much the same way, one could say that Birth of a Nation was “emotionally true” for Southern racists, or that Ben Stein’s Expelled was “emotionally true” for creationists. Again, I’d say that the “emotional truth” of the conspiracy hypothesis is further evidence for its factual falsehood: for it explains how so many people could come to believe in a conspiracy even if the evidence for one were dirt-poor.
20. At its core, every conspiracy argument seems to be built out of “holes”: “the details that don’t add up in the official account,” “the questions that haven’t been answered,” etc. What I’ve never found is a truly coherent alternative scenario: just one “hole” after another. This pattern is the single most important red flag for me, because it suggests that the JFK conspiracy theorists view themselves as basically defense attorneys: people who only need to sow enough doubts, rather than establish the reality of what happened. Crucially, creationism, 9/11 trutherism, and every other elaborate-yet-totally-wrong intellectual edifice I’ve ever encountered has operated on precisely the same “defense attorney principle”: “if we can just raise enough doubts about the other side’s case, we win!” But that’s a terrible approach to knowledge, once you’ve seen firsthand how a skilled arguer can raise unlimited doubts even about the nonexistence of a monster under your bed. Such arguers are hoping, of course, that you’ll find their monster hypothesis so much more fun, exciting, and ironically comforting than the “random sounds in the night hypothesis,” that it won’t even occur to you to demand they show you their monster.
Further reading: this article in Slate.
Who was the first scientist to warn of Global Warning? These questions are complicated, but I would say it was Bing Crosby in a paper called White Christmas. Here are the first two lines:
I'm dreaming of a white christmas
Just like the ones I used to know
Why are there no more white christmas's? Because global warming made it stop snowing!
Why do otherwise intelligent people refuse to believe that Global Warming is real and is caused by humans and we we need to do something about it? I have a conjecture and an analog. Here is what I think the reasoning is
- Republicans have the following AXIOM (until they are in office): government IS the problem, not the solution. More than this, they think that there is NO problem that requires government action.
- Consequence: Government should do NOTHING about Global Warming.
- Since Government shouldn't do anything about Global Warming, it is not a problem.
Rather than rethink their AXIOM they accept the conclusion that Global Warming is either not a problem or not caused by humans. The shame of it is that there ARE economically viable ways, perhaps moderate republican ways, to fight global warming- some version of Cap-and-trade, or pay-to-pollute. And getting off of Fossil Fuels would be good for other reasons. I can picture history going a different way so that Republicans want more fuel-eff cars to get us off of Mideast Oil. I can picture a history where the insurance companies are more powerful than the oil companies for lobbying and hence Government takes LOTS of action against global warming.
Are their things in math where people accept an axiom despite its absurd consequences?Yes:
- Most math people believe the Axiom of Choice.
- Consequence: the Banach-Tarski Paradox
Rather than rethink their AXIOM they accept the absurd conclusion that you can break a ball into 5 pieces, reassemble, and get twice the volume. Fortunately, believing this does not endanger the planet.
Back from 5 weeks of international travel, I continue to seek the best solution in my quest for reasonably priced data service when outside the USA.
Data has become a must for me when on the road. In spite of the fact that we all lived without it a decade ago, I find it very frustrating if it’s not available (or priced at $15,000 per gigabyte, which is the typical default roaming rate.) It’s how I find directions, food, tourist info and keep in touch with others.
For a while my normal practice, if in a country for more than a few days, has been to purchase a local SIM card, and of course to have an unlocked GSM phone. Usually local SIMs are now available with 500mb to 1gb of data for $10 to $20. There are various web sites that list the local data providers to help you choose. The best prices tend to come from the MVNOs — not the main incumbent carriers — but even the big carriers tend to have decent prepaid deals. These usually come with some voice minutes and texting. This is useful though I don’t do a lot of voice minutes when overseas due to time zones. I use them to reach local friends, book hotels, check restaurants, and with my companion.
Annoyingly, though I have bought many of these SIMs, even for data, it’s not nearly as nice and easy as it should be. A large fraction of the time, something goes wrong. read more »
The hassles of local SIMs
- It can often be a pain to research and pick the right carrier, and then to find one of their stores, and get the purchase done. This was particularly true in the past, when selling a SIM to a random foreigner was not a common event at many stores. You have to go out of your way, and deal with people who don’t speak your language. Some providers put a store in the arrival area of the airport, which is great, though they tend to be the more expensive cards.
- Until you get the new SIM, you are faced with very expensive roaming.
- Research does matter. In England (where language is not a problem) some carriers give you your data bundle free when you put 10 pounds on the card, others charge you those 10 pounds, leaving you with no voice minutes.
- Once you get the card, you often have to deal with web sites, menus and voice prompts not in your language. Setting up the voicemail is already a pain, and is far worse if you can’t understand the prompts.
- Fixing odd problems is difficult in an unfamiliar system. My Orange card had a package of 500mb in it for 10 Euros, (great) but kept draining the money I put on it, leaving it unusable for making calls and texts, and though I can read and speak modest French, I was unable to find the cause.
- There are always issues of prepaid cards for short use. If you put too much in the card, it’s wasted unless you are coming back soon. If you don’t put enough in, you have to run around buying and adding refills — again with prompts not in your language. Carriers would do well to let you add a lot to the card, and then refund it to you on request. This would make me put more in the card, and use the phone more, so it’s a win for them.
- As noted, balances usually expire quickly, and cards often expire after 6 months or a year if not used. Though some cards are lasting longer.
- In some countries, they won’t let you refill from a credit card, which means you must buy cards at local shops with cash, and always have a card handy — then throw away the spare cards when you leave, wasted.
- You need to learn and give a new phone number to people. You may be able to forward your old number, but often that comes at a high cost. As a plus, you make it much cheaper for locals to call and text you, while making it more expensive for people back home to reach you (unless you forward and eat many times that cost.) Do texts forward? You do get the “advantage” that incoming calls and texts are free.
- Calls back home may or may not be quite expensive, but usually are much less than roaming rates on your home SIM.
- If you move to a different country, you usually have to do it all over again — shop again, and have a new number. In Europe, where it is common to hop from country to country this becomes a real issue. Some prepaid plans allow tolerable voice roaming in other countries, though data roaming tends to still be expensive on prepaid, in spite of a European order to reduce it.
- You are going to pay $10 to $20 plus your time for all this, and if all you want is to do a few voice minutes and some texts and keep your data usage to wifi, you might not come out ahead on a short trip.
T-Mobile’s new solution
Fourth Annual Holiday Discount Puzzle
Solve this puzzle for 10% off any order!
It's that time of year again, time for the Pavel's Puzzles annual Holiday Discount Puzzle! As in past years, I've created a brand-new multi-stage puzzle that leads to a one-word solution. That solution word is a special discount code that you can use when making an order from Pavel's Puzzles to receive a 10% discount on any number of puzzles. Even better, once you have the discount code, you can use it over and over again, on as many orders as you like, between now and the end of 2013!
Do you have what it takes to solve the discount puzzle? (Indeed, what does it take? Well, never mind that...)
To get started discovering the 2013 holiday discount code, carefully cut out the nine square pieces linked to by the image below and arrange them, without overlapping, within the frame on the second page of that PDF file. Exactly how you should arrange them, and what you should do after that are for you to determine. I know you’ll enjoy working that out...
Once you’ve found the code, make any order at http://www.pavelspuzzles.com and enter the code in the “instructions to merchant” space at PayPal. When I get the order, I’ll issue you a refund for 10% of your order amount (excluding tax and shipping). And remember: you get that same discount for every order you make through the end of 2013!
We have one more holiday tradition here at Pavel's Puzzles: to sweeten the discount deal, I've recently added a whole slew of new products to the website! It's been a particularly productive year here, with no fewer than thirteen new puzzles for you to peruse and be perplexed by!
First up are a trio of classic puzzle designs, now available in new editions from Pavel's Puzzles.
The Buttonhole Puzzle
is truly one of the greatest designs of all time: it's just a stick and some string, but I'll bet it gives you fits to take it off once it's attached! By far my most popular design, I've already sold hundreds of copies of this devilish delight since introducing it at the farmer's market this summer.
The classic dissection puzzle ‘T’ Party has been stumping people for many decades: can you assemble the four simple pieces into a perfect block letter ‘T’? Preying on a psychological ‘blind spot’, you'll swear this puzzle can't be solved, just before it finally clicks together for you!
Finally, The Four T's Puzzle is a deceptively simple and very elegant 2D packing puzzle: it's easy to fit all four pieces into the one-star tray, but that two-star tray is another matter entirely!
Did you notice that the Four T's Puzzle above is packaged in a CD ‘jewel case’? You can't tell from the picture, but so is ‘T’ Party, and we also have new CD jewel-case editions of three of our best-selling earlier designs! These convenient and economical editions are ideal for travel, for family fun nights, and (dare I say it) for stocking stuffers! Be sure to check out these new versions of Square Dance, Easy Eight / Hard Eight and Sleazier.
This year, I expanded into the category of sequential-movement puzzles with Marble March, a classic, tricky marble-jumping puzzle, and Marble March 2, my own original (and surprisingly more difficult) variant of that design. These handsome, solid puzzles will look great on any desk or coffee table, and your guests won't be able to resist trying “just one more time” to solve them.
I also broke into the category of disentanglement puzzles this summer. In addition to the Buttonhole puzzle above, I've added five other such designs, all made from shiny brass chain and PVC plumbing parts!
Star-Crossed is my version of an old classic design, now with a romantic twist. These two young lovers (represented here by the two smallest parts) have been cruelly separated, each on their own loop of chain. Can you reunite the lovers, bringing them together onto the same loop?
Several years ago, German designer Bernhard Wiezorke produced his wonderfully nasty Hemispheres puzzle, and shortly thereafter American Gary Foshee created his variant design, Holey Bolt. Neither puzzle is widely available, though, and that's been a real shame, because it's a doozy!
Now, I've stepped into the breach with my own version, The Bickering Couple. You can think of it as a sequel to Star-Crossed, a little bit later in the lovers' relationship. Now, the couple have had a falling out, turning their backs on one another. Your job, of course, is to reconcile these troubled lovers, getting them back face-to-face. (What they do after that is none of our concern, ...)
Rounding out the new disentanglement puzzles are a set of three versions of The Plumber's Candelabrum. This puzzle comes in three-, four-, and five-stick variants, with the difficulty going up exponentially with the size. Your goal is to completely remove the rubber O-ring from the candelabrum, somehow moving it along from chain to chain.
Naturally, all of our earlier puzzle designs are still available as well. My holiday discount puzzle is a perfect way to satisfy (or frustrate) that puzzling person on your gift list (or perhaps yourself!) while saving a little cash at the same time.
Happy holidays, from Pavel's Puzzles!
(This post was inspired by Adam Winklers awesome book
Gunfight: The Battle over the Right to Bear Arms in America
Disclaimers one: Adam Winkler is my cousin and I got a free copy.
Question: Should I give him a free copy of my VDW book when it comes out?
Disclaimer two: Scott did a post on a related matter here
If someone started an Institute to prove Graph Isomorphism is in P
be very odd since it could be that GI is not in P.
If someone started an Institute to study Graph Isomorphism
that would be
much less odd (though still somewhat odd).
Does it make sense to have an openly biased think tank?
- If a pro-gun-control person writes a book that proves that there weren't that many
guns in America in the early 1800's would you believe it?
- If an anti-gun-control person writes a book claming that the more guns there are
the less crime there is, would you believe it?
- The CATO Institute: A Libertarian Think Tank.
If they did an honest study of gun control and concluded that it does reduce
crime then would they publish it? I honestly do not know.
If they did an honest study of gun control and concluded that it increases
crime then would anyone believe it? Being openly biased might undermine their credibility.
- The Tobacco Institute (they no longer exist). They produced reports
claiming that smoking was not unhealthy (or perhaps that the evidence is incomplete).
They were employed by the Tobacco industry. Did they ever have any credibility?
Did they do any unbiased science, perhaps on non-smoking issues?
I honestly don't know.
It is tempting to say Scientists should not have an opinion before they do a study
. But this is clearly not correct in theory or practice. Scientists do indeed have an opinion, even an interest, in what a study will tell. Why is that different from the Tobacco institute?
- An honest scientist's preconceived notions are hopefully also based on science and not on who is paying him and not on other non-science factors.
- An honest scientist, when faced with evidence that they are wrong, will hopefully pursue that evidence and perhaps change their mind. This might be easier in math than in science since Proof is our accepted criteria. For example, I doubt there are diehards who still think that NL ≠ coNL.
T. L. has a co-worker, Taran, who was obviously the best there was, is, and ever will be. Taran had a penchant for using the word obviously. In almost every sentence. Of every paragraph. Of...