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Combinatorial Optimization May 24, 2010

Posted by CK in Research.
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Although I’m not a huge fan of Papadimitriou’s and Steiglitz’ book, one has to appreciate the things that set this book apart from many others in the area. Looking at section 17.3 on approximation schemes, the intuitive description of the topic is excellent. Starting with the simplest definition of dynamic programming that I’ve ever encountered, and by far the best example ever (example 17.3 — why hasn’t anyone included something so clear in all the places I’ve looked?), then continuing to (F)PTAS so smoothly that one doesn’t even notice.

Bonus points for the last sentence before definition 17.3:

Such a favorable state of affairs naturally calls for a definition.

Too many “17.3” in this post.


Onyx Boox 60, update May 24, 2010

Posted by CK in IT, Mobility, Productivity.
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I’m loving it.

After a week of using it, I haven’t regretted the purchase at all. PDF compatibility is spectacular, so the main criterion is fully covered. The screen performed very well under all circumstances, even strong daylight (although, it would be nice for dim-light reading if it would be slightly brighter). Reflections are marginal and definitely not an issue. Controls are very intuitive, and the software covers for everything. The touch screen works very well, accurately and is very responsive for e-ink. Judging from other e-readers I’ve seen, this one is definitely in the fast lane. As regards the size of the screen, which is quite small, if you are reading in landscape mode and zoom to selection, it’s totally fine (at least by my standards). Portrait just doesn’t work for normal PDF papers (which is my main use case), especially double-column is completely unreadable. Finally, the included case is very nice indeed, good quality and holds/protects the reader beautifully.

The only thing that needs to be fixed, is to memorize screen offsets when leaving a document. Although not a major problem, it’s a hassle to re-adjust margins every time.

I also experienced a crash within the week, but I assume the firmware is still maturing. Not a problem, really.

Onyx Boox 60 May 17, 2010

Posted by CK in IT, Mobility.
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Being sick of waiting for the Que and shocked by its price tag, I decided to look out there for something else. It took a lot of page views to find the right one, but I think I eventually did. This morning I received the Boox 60 e-book reader by Onyx. It is the same product you can also find re-branded as the BeBook Neo.

Pros: The screen is fairly good to look at (albeit too small, I’ll get to that in the “cons”). Construction feels good and solid. PDF rendering is superb (it was the main reason I chose it, they are partnering with Adobe). Reflowing documents works like a charm. Overall, my first impressions are very positive.

Cons: 6 inches is definitely not enough to read full-page documents. This can be largely improved by switching to landscape viewing, increasing font size, or zooming a lot. The problem with increasing font sizes is that, due to text reflowing, images are not being displayed anymore — or at least not in the PDF I was looking at. Also, some settings are often reset, maybe I’ve missed something though.

I haven’t tested yet things like the WiFi, playing MP3s and the like. I’ll get back with a more complete review after a few days of using it.

Vodafone Germany wrap-up May 14, 2010

Posted by CK in Networking, Personal.
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Update: Today I found out that they charged me ~112 euros for early contract cancellation. I don’t know how to react and remain politically correct.

First things first: AVOID THIS COMPANY AT ALL COSTS. I received notoriously bad service, and eventually a disconnection that wasn’t my fault, at the most critical time for me — when I’m writing my doctoral thesis.

First, it was their incompetence providing me with a working phone, until I solved the problem for them.

Then, I asked them in writing to cancel my contract on August, and they replied they will cancel it in November, although their salesmen had told me I can quit whenever I wanted.

Then I wrote them that I am a university student leaving the country, and therefore I want them to cancel it in August, not November. They replied they will cancel it in May, in a week’s time after their notification.

I spoke to their customer care this last Monday, the guy said he’d try to roll it back because it was clearly a Vodafone mistake, and we should check back on Wednesday about the status of the rollback request. These requests go to Deutsche Telekom and once in, you never know if you can do something about it.

On Wednesday, the lady I (well, my German-speaking colleague) spoke to said she couldn’t see anything about such a request, and I should send a fax to describe the problem. I did, then someone called me (which is really a rare thing), said again he would try to roll back the cancellation request and call me back to notify me what is the status of things. Needless to say, he never called me back.

An hour ago, my connection disappeared. I have no ADSL anymore, it’s not my fault, and according to the latest Vodafone representative I spoke to today, there is nothing I can do about it. Her advice was to buy a 3G USB stick.

If anyone knows what I can do to kick them, please tell me. This is disaster. I was disconnected 3 months before the time I asked, and they pretend it’s my fault.

Should I laugh or should I cry? May 10, 2010

Posted by CK in Networking, Personal.
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Readers of this blog are already familiar with my bitter experience with Vodafone Germany (details here and here). Long story short, in the latest episode of this series I asked for my connection to be interrupted at the end of the summer, giving them a good lead time for that (typically, contracts require a 3-month notice). On Friday, I got a letter from Vodafone stating that my phone/internet connection will be cancelled at the end of this week. At this point in time, this would be pure disaster, my thesis’ Titanic. Calling them on the phone, they recognized their mistake, apologized, and said they don’t know if they can do something because they have already asked Deutsche Telecom to disconnect me on Friday.

Seriously, Vodafone, how difficult is it to get your act together and be professional? Are you really amateurs? I really wish I had never made that contract.

Top 10 reasons you should leave Facebook May 6, 2010

Posted by CK in Funny, IT, Networking.
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A wonderful, wonderful article over here explaining all the important reasons why you should leave Facebook. Highly recommended, as is also this video linked from the article. Enjoy.