Kindle DX dropped its price by about $100, I guess at the pressure of iPad and other ebook devices. This is good news to a lot of people who do not really want to read books on LCD/LED-based technologies. I recently lost my Kindle in a trip, so it is time to think about the next device to get to replace it.

Wei Sun recently sent me an email asking about my opinions about DX, I will put my thoughts below, as my review of DX after using it for about 6 months.

(1) How many academic papers do you read on it, and on printed form?

I put quite some papers into it, it indeed reduced my printing. But journals like MgtSci, MktSci, ISR have too small fonts (kindle’s font is slightly smaller than the real journals), so in the end, it is still not too comfortable to read on DX. Once you rotate it to read in landscape mode, the fonts are larger (larger than the real journals), but you need to do a lot of page-ups and -downs to read them. If the new version can improve the speed of page flipping, it will be better, otherwise, it is a headache to read journal papers. AER and JPE are fine because they have large margins and kindle can crop them automatically.

(2) Do you find it helpful for academic research?

Yes. I mostly read ebooks on it. It is best for ebooks and I love it. For PDF versions of ebooks, I can use a software called calibre to convert to ebook format so I can change the font on the device. DX has 3GB, I put hundreds of books into it, there’s plenty of space.

(3) In your opinion, are there any better alternatives? How about Apple ipad?

ipad is not based on E-ink technology, so it does not make a big difference from reading on a laptop screen. The biggest reason for me to buy kindle is that it feels like reading from paper on kindle, and it’s good to the eyes. For reading papers, I would not use ipad. An alternative to kindle is a device called QUE, you can google for it. I learned about it after I bought my kindle last december, but it then pushed off the release date, the most recent news was that it announced it would release on June 25. I don’t think many people have evaluated it now, but this half year delay for sure put a big damage on the product. For one, ipad is out, many people simply get ipad, second, kindle dx has dropped price, QUE’s price at $500 is too high now. But a nice thing is it has the largest possible E-ink screen on the market. The monitor is similar to normal letter-sized paper, so it will be like exactly reading a printed paper.

(4) Overall, do you recommend it at $400 as a research tool?

Bottomline: I would say if you read a lot of books like I do now (I did not have time to read books when I was a student), it will be really useful. Otherwise, hold for a little while to see how QUE performs.

(本文所有照片都可以点击看大图)

标题是春天的巴黎的意思。好久没有写中文的东西了，上次还是两年前写南京的游记，今天写写巴黎之行。

小豆诧异了半天，说我变风格了。

这次是受邀于巴黎第十大学(Universite de Paris X) 和 Universite de Rennes I参加一个workshop。本来假期时间很紧，不想去的，不过和Erik的东西需要有个契机推动一下，另外对方报销所有费用，所以就勉为其难的去了，呵呵。

巴黎大学也叫 Sorbonne, 我住的附近路名都叫 Rue de la Sorbonne。这里也是著名的拉丁区，以前做学术的都要讲拉丁文，所以这个地方就叫Latin Quarter。国内经常看到左岸这，左岸那的，就是指的这个区域，因在塞纳河的左岸而得名，是小资一派的麦加圣地。

附近著名的景点就是卢森堡公园 (Jardin du Luxembourg)：里面以诸多文艺愤青的雕像而著名，我看到了乔治桑（George Sand）, 肖邦和她同居10年之久，并曾经为她谱过曲。

Workshop两天，日程及其紧，比较失望的是第一天不少talk都很preliminary，没有什么意思，好在第二天有些不错的paper。另外见到了一直想交流一下的几个人，所以时间不能算浪费啦。 巴黎偶来过3次了，这次是第一次做学术交流而来，很久之前给公司做路演，参加展会，去年来参加wedding，所以身份从白领，到游客，再到学者，每次的体会也会不同。

中午的午餐很别致，我吃得不多，和与会者聊天更有意思一些。

Paul Belleflamme给我的印象很深，以前做Piracy和Pricing of Music研究的时候读过他的文章，最近他出了一本IO的书

有机会会买一本读一下。

我的那个session叫做 Socially Optimal Incentives，看了一下，至少还可以在另外两个session讲我另外的paper，分别是 Online Advertising 和 User Generated Content （UGC）。

Workshop结束的时候正好赶上法国的Gay parade，看到不少有趣的人。

队伍里有帅哥美女，也有大爷和小朋友。那个白胡子大爷举的旗子是法国西北部著名的Brittany的旗子，去年参加Grace和Benoit的婚礼曾经去过。

这些人都很友善，而且游行时都很proud，偶很受感染。（不是说取向方面，而是positive面对人生方面）。

第一天会议结束后随便走了走，照了些像，都是去过的地方，所以玩了些艺术手法：

晚上和组织会议的Eric和Thierry吃饭，竟然用了4个小时，8点一直到12点多。完了顺道去拍了几张夜景照片。

第二天下午有一点点时间，就在傍晚前拍了些日落前后的照片，效果更佳。

我自己最喜欢的是这下面的巴黎圣母院的照片：

开完会后的周日，我很想去巴黎附近的小城看看，其实有不少选择的，可以去枫丹白露Fontainebleu（直译是蓝喷泉的意思），或者一个叫Provins的地方看中世纪的古堡和教堂，或者去重游Brittany，去上次没有去过的Mont Saint-Michel, 也可以去Loire谷看城堡，不过这几个地方小豆也都没有去过，而且有些地方开车去比较方便，所以可以留着下次一起去。最后决定了去一个叫Chartre的地方，离巴黎有80公里远，此地有名气仅次于巴黎圣母院的一个教堂(Cathédrale Notre-Dame de Chartres)。火车站就在离我不远的Montpanasse，走路就可以到了。卖票的黑人大叔态度不怎么样，所以我费了半天劲才figure out怎么找火车的站台，多亏当年学过一年法语的底子，连猜带问人，总算上了车。一个小时后火车开到一个叫Maintenon的地方，我还在车上美呢，列车员过来告诉我这个车马上就原路返回巴黎了，下面要换坐大巴了。我还是很牛的，这些法语都听懂啦。

大巴开了20分钟远远就看到那个教堂了，下了车是火车站(Gare Chartre):

小城很不错，教堂也很壮观，当天还有礼拜，正好赶上了

周一去巴黎大学访问，顺便去了旁边的L’Ecole Normale Superieur 是居里夫人等牛人工作过的地方，出过12个诺贝尔奖和9个菲尔兹奖的得主。

当然在巴黎还有必做的两件事：美食和购物。

我每次去都不会错过的就是 鹅肝酱（foie gras），牛排（entrecote），生蚝和海鲜盘（fruits de mer）和比利时的Moules。在我附近有一家我仰慕已久的餐馆叫 Les Papilles，刚到的那天就去采了点，准备周日去，结果他们很拽，周日休息。 等到周一去，waiter告诉我又不营业，只有等到周二中午才在走前匆匆去试一下。结果吃到了我此生最好吃的午餐。本来没有太多期望的，所以就点了不起眼的”marmite du marché”, 就是个午餐套餐。上来的鸭胸肉火候几乎perfect, 撒些旁边的颗粒状海盐吃，简直让我惊艳万分。比起前几日在比其贵很多的餐厅里吃过的鸭胸肉还好，水准直追米其林3星的水平。

购物方面就是四处转转了，看到LV门口永远排着一串中国，韩国和日本的女士们。去老佛爷的酒窖看看，一个华人sales围着我让我买Chateau Lafite， 当我是国内暴发户啊。最后买了性价比极高的 Chateau Canon 05 和 Chateau Magdaleine 03。

A forever classic. I’m touched each time I hear it.

Now the original:

XX and WW are old enough for me to conduct scientific research on them now.

Today I did the famous marshmallow experiment: I gave them each a piece of gummy bear vitamin in the morning, and I told them if they can defer eating the gummy bear till noon, I’ll give one more piece.

According to the theory, kids with good impulse control would defer the consumption.� They generally show good academic performance in a later stage of their lives.� So I’m eager to see how my kids perform in this test.

To my delight, both kids chose to wait.� To examine whether their actions are consistent with their choices, I put the gummy bears on the table and said, I’ll leave them here, and you can take them any time you want, at noon, if I still see them, I’ll put one more for each of you.

Then XX immediately said: “Dad, I change my mind, I’m going to eat it now.” Hmm, that’s not what I expected, XX is quite smart and not bad in self control, if one of them would choose immediate consumption, she should not be the one.� She then said:”If I leave it here, mommy can eat it secretly. WW can also steal it.” Well, from my experience, these are indeed not impossible scenarios.� When I think about XX’s decision making process, I guess she outdid those kids with self-control, she could take potential risks into her consideration and make corresponding decisions.� Given the existence of the risks, it is indeed her best strategy to eat the gummy bear immediately. Getting one bird in the hand is indeed better than having two in the bush!

Obviously AER’s LaTeX template does not generate the references that comply to the guideline (http://www.aeaweb.org/aer/styleguide.php).

When it is time to submit the final version of our paper “Group Size and Incentives to Contribute: A Natural Experiment at Chinese Wikipedia,” it took me a while to figure out how to modify the original aer.bst file.

To save some time for myself and others, here is the modified bst file.

First letter was from our university president, explaining that in light of the recent financial crisis, we have to follow the new budget plan and reduce the salary by 5.4%.

Second letter was from my daughter’s school, explaining that in light of the recent financial crisis, they have to follow the new budget plan and increase the tuition by 5%.

What an ironic world.

I need to convert a bunch of isbn numbers from the 13-digit format to the 10-digit format.

Figured out the algorithm, and implemented the following subroutine in PERL.� It should be fairly simple to port it to other languages.

sub isbn1310{

my�� $isbn10="$isbn13[3]"."$isbn13[4]"."$isbn13[5]"."$isbn13[6]"."$isbn13[7]"."$isbn13[8]"."$isbn13[9]"."$isbn13[10]"."$isbn13[11]"."$last";
return $isbn10;
}


For completeness, here is the program to convert ISBN10 back ISBN13

sub isbn1013{