Many math problems are fascinating. Often they are also difficult, so that only those who have high enough education can understand their beauty. But sometimes a really simple problem – such that anyone with just the elementary school knowledge can solve it – can be quite cute as well. Most elementary school math questions are truly boring, but it’s possible to add some spice to this mass.
1 (I knew this earlier) “Dried cucumbers”:
Cucumber contains 99% of water. A box of cucumbers weighs 100kg. During winter storage, cucumbers dried out so that they now contain only 98% of water. How much does the box weigh now?
2 (I got this today, which inspired me for this post) “Probability for doctors”:
Assume a test for a rare disease (which affects 1 person in a million) is 99.99% accurate. A patient tests positive. What are the probabilities he actually has the disease?
Bicycle mudguards are frequently made shorter than they should have been. I was not able to find a front mudguard which would protect front chainrings from water jets pouring from the front wheel. So I made my own from a 2mm thick rubber sheet. It is heavy and non-aerodynamic. It is heavy-duty! It makes difference when riding in the rain. It is tested. Highly recommended for bike commuters.
Nokia has released own online maps, “maps.ovi.com”. I have tried this, and found them to be so much inferior to the competitors that I even feel ashamed for its home country (which is now my home country as well). I think in this area Google Maps set the reference, so I’ve done a small comparison of the two. Continue reading
Living in Helsinki region, looking for a company for evening sporty road rides? Come to Vantaankoski (the home mark on the map below) on Tuesdays and Thursdays by 18:00.
What to expect there? Continue reading
Has your web site ever been “infected”?
This happened to me today, first time in my life. Hello from go00ogle.net. Below are technical details on what exactly happened, why I did not suffer any damage, and what I recommend to do in order to reduce your own susceptibility. The article is written for a non-technical reader.
Article at Groklaw.
My random pick:
“If Europe leads the way in this [allowing algorithms to be patented], I expect many Americans would want to emigrate so that they could continue to innovate in peace.”
I want to buy a silent Linux desktop computer. No need to be any “high-end” otherwise.
This turned out to be a nontrivial task. After hours of browsing and listening to advices (thanks to my friends who already gave some!), I see the following options:
Wolfram Research, probably most known for their Mathematica calculation product, has launched an online service which makes various calculations and visualizations for free, and with just a web browser:
This project makes me really respect Wolfram. I spent quite some time browsing the examples, almost exclusively from the “mathematics” part, picking like a shy visitor at other areas. Some of my online friends write that “knowledge becomes less of a fashion in our times”. I do not agree a bit. Just look at this product.
10 and more years back, when I studied mathematics, I was an active user and promoter of the (La)TeX typesetting system. Since then, I almost did not use it, but kept the warmest memories of this creation “by mathematicians, for mathematicians”. Yesterday… I can’t say I changed my mind, but I’m not so sure any more about my attitude.
I had to remake a one-page document, for which I already had an old LaTeX template source. Edit the source, “make”, and a nice PDF is ready. Well, now the text which I inserted contained the @ sign. And of course (pdf)LaTeX did not compile.
I did not remember what should one do to typeset ‘@’ literally. I certainly remembered it 10 years back, but that’s not the kind of knowledge which stays alive when not used. It took me about 15 minutes to find the answer.
And now I’m not sure whether I shall promote TeX at all. From my viewpoint, this 15 minutes is unacceptably too much for such “problem” (actually, the very fact that this made a problem, is unacceptable in my current view). I expected the first link in Google search to give the solution, but the reality was very far from that. And – unfortunately for the others – I consider myself as a quite experienced (La)TeX user: I followed news:comp.text.tex, created own document classes, which were also used by other people, and so on. I knew well how it works. I knew where to look for documentation, and what kind of documentation I need. And still this thing, which should never be a stumble at all, took me 15 minutes. I can easily imagine that it takes full day from a person new to the TeX world.
Conclusion: sorry, none at the moment…
I’ve started writing about my last year bike trip in the Indian Himalayas. Before I had not forced myself to more than one blog post and an unsorted pile of photos. Now I’ve started with a short illustrated text about practical issues, answering questions which I had at the planning stage:
Cycling in Himachal Pradesh: practical issues
My next plan is to publish the daybook with facts and impressions. Stay tuned.
We’ve done a great sunny full-day ride on our tandem with a kidback plus two other bikes. The target was Vanhankaupungin koski (stream and a waterfall), one of the city attractions we had not visited before.
This made 56 km and 10 hours door-to-door. I think it was the first day of the year when it was possible to cycle in shorts – not morning and evening though.
Map of the ride: Continue reading
Here is a map of my 8 March ride with IK-32 club.
View Larger Map
My family spent a week of vacation in a rented cottage house around Kuopio (Finland).
This was an utter joy for me. I love winter, that is, the real winter – meaning lots of snow, frozen lakes, and beating the ski track through the intact surfaces. Continue reading
A motivated-looking female character illustrates the software update process. Picture from nokia.com
Nokia gives an option to update the phone’s software, at least, for the more expensive models. I do not know, and would like to know, how other mobile phone vendors score in this area. Below is my rant about Nokia way of doing it. The writing is in negative tone, because things are noticed only when they do not
work as expected. I’m interested if there is a vendor who does it better (some do not allow the user to update firmware at all – you must go to the service center for that!)
Are you sometimes getting a thought that the life feels a bit too routine? That you’ve done nothing really crazy for a long time?
Even if so, the good news is that there is always an escape from such dead end! That is, unicycling!
What a vandalism is this? Turning a keyboard into two pieces of junk?
No, it’s just the opposite – Bringing the Order, and Getting Rid of Junk!
I never use the “numeric keypad” on the right side. And it takes valuable space from my right hand. So what’s the problem if I got the hacksaw? Read on how I did it (with pictures and instructions for followers).
The winter – meaning, snow and ice – is not yet coming to our region, but I somehow feel that the roadbike season is over. With this thought in mind, I rebuilt my road (or cross) bike with flat bars.
I’ve uploaded the pictures from the “cycling” part of my Himalaya trip.
Some thumbnails: Continue reading
It has been a month since I have returned from solo cycling trip in Indian Himalayas.
Impressions clearly overloaded my brain. This was first time I’ve been to Real Mountains – the highest pass, Kunzum, was at 4500m. And this was my first time I’ve been to a non-Western country (not counting my home Russia, which I’d put “on the border”).
The route was easy: start at Shimla, and follow the National Highway 22 (with some variations in the beginning) until Manali. Oh the highway… Never have seen anything like this before.
Numbers, mostly of interest to cyclists only:
- 9 ride days
- 750km covered
- Total altitude gain is still not counted, although three biggest gains were 1600, 1300 and 1000 meters
In fact the impressions of India as a country overweigh the “mountain-cycling” impressions. It deserves much more than one blog post – even much more than one book. All my perception of the surrounding world is now a little bit different than it was before. Probably such thing is called “cultural shock”. I’m so happy that this happened; now I see how terribly narrow view I previously had.
Of the real India, I have seen only Chandigarh, which is described in all guides as most comfortable city in the country. Still it is, of course, Indian city (just like my home Saint Petersburg is the most European of the Russian cities, but still fully Russian).
I’m feeling own deficiency of not being a good writer to describe my thoughts about these two weeks. So far I have produced a technical report, with details for cyclists such as what tires to put on your bike and how much food to carry.
All pictures (unprocessed) piled here.
Today evening I was catching last weekend of the school vacation. Starting from tomorrow, my time limits for the outdoor activities again become much more strict. And there was a great chance to use it: in a company of Antero and Matti (thanks for calling me in!), we made 100km at average speed a bit over 30 km/h.
View Larger Map
Now I have 2000km on my roadbike’s computer during this season. Quite an achievement for me, taking into account that I was not cycling during 3 weeks when we went out for family trips, and that I do most of my everyday commuting on the other bicycle. Now intensive collection of kilometers slows down; I have a positive feeling that the time available to collect them was used at full extent.