Author Archives: Liyun

About Liyun

M.Sc. Economics from Barcelona Graduate School of Economics.

recent research trend of NBER working papers, since 2013

Recent days I got curious that what topics attract most of economists' attentions. NBER working paper series contain some relatively new research fruits so I used it as the raw input.

It is not hard to extract key words from these papers' titles. After that,  I made a further step that matched all single keys to academic keywords on Microsoft Academic.

NBER working paper trend

From a glance, I manage to identify some hot keys:

Price. Health. Social. Policy/Public. Risk/asset/liquidity. Growth. Insurance. Education/School.

For reproducible purpose, my code is here.

 

grab_url <- c("http://www.nber.org/new_archive/mar14.html",
              "http://www.nber.org/new_archive/dec13.html",
              "http://www.nber.org/new_archive/sep13.html",
              "http://www.nber.org/new_archive/jun13.html",
              "http://www.nber.org/new_archive/mar13.html")

library(RCurl)
require(XML)

grab_paper <- function (grab) {
  webpage <- getURLContent(grab)
  web_content <- htmlParse(webpage,asText = TRUE)
  paper_title <- sapply(getNodeSet(web_content, path="//li/a[1]"),xmlValue)
  author <- sapply(getNodeSet(web_content, path="//li/text()[1]") ,xmlValue)
  paper_author <- data.frame(paper_title = paper_title, author = author)
  return(paper_author)
}

library(plyr)
paper_all <- ldply(grab_url,grab_paper)

titles <- strsplit(as.character(paper_all$paper_title),split="[[:space:]|[:punct:]]")
titles <- unlist(titles)

library(tm)
library(SnowballC)
titles_short <- wordStem(titles)
Freq2 <- data.frame(table(titles_short))
Freq2 <- arrange(Freq2, desc(Freq))
Freq2 <- Freq2[nchar(as.character(Freq2$titles_short))>3,]
Freq2 <- subset(Freq2, !titles_short %in% stopwords("SMART"))
Freq2$word <- reorder(Freq2$titles_short,X = nrow(Freq2) - 1:nrow(Freq2))
Freq2$common <- Freq2$word %in% c("Evidenc","Effect","Econom","Impact","Experiment","Model","Measur","Rate","Economi",
                                  "High","Data","Long","Chang","Great","Estimat","Outcom","Program","Analysi","Busi"
                                  ,"Learn","More","What")
library(ggplot2)
ggplot(Freq2[1:100,])+geom_bar(aes(x=word,y=Freq,fill = common,alpha=!common))+coord_flip()

### get some keywords from Bing academic
start_id_Set = (0:5)*100+1
require(RCurl)
require(XML)
# start_id =1
# 

get_keywords_table <- function (start_id) {
  end_id = start_id+100-1
  keyword_url <- paste0("http://academic.research.microsoft.com/RankList?entitytype=8&topDomainID=7&subDomainID=0&last=0&start=",start_id,"&end=",end_id)
  keyword_page <- getURLContent(keyword_url)
  keyword_page <- htmlParse(keyword_page,asText = TRUE)
  keyword_table <- getNodeSet(keyword_page, path="id('ctl00_MainContent_divRankList')//table")
  table_df <- readHTMLTable(keyword_table[[1]])
  names(table_df) <- c("rowid","Keywords"   ,  "Publications" ,"Citations")
  return (table_df)
}

require(plyr)
keywords_set <- ldply(start_id_Set,get_keywords_table)

save(keywords_set, file="keywords_set.rdata")

 

to be an eBay seller...and explore the social network effect

It is interesting to work for eBay; however, most of the time I am looking at the massive data without really thinking about how they are generated... for instance, I have no idea how difficult it should be to be a successful seller on eBay. It somehow sounds a little wired that we talk about mechanism design (say, whether eBay's ecological system is better than Taobao's) without personal experience.

To step in, I should try - and there was a precious opportunity for me to do so! After the China-R conference in Beijing, two professors from Australia (Graham Williams and John Maindonald) asked if they could buy additional packs of the playing cards somewhere so they could share with their colleagues and friends. Then why not on eBay?

Then I typed "ebay.com" in my browser... log in...sell...The photos were prepared several months before... upload... done!

However, when I was trying to copy the link...it was so long!

http://www.ebay.com/itm/R-Language-Playing-Cards-Postcard-Suit-Best-Gift-Statisticians-/321134725623

Then I noticed the lovely "share to twitter" button on the left ^O^ Let me just use this one!

A simple click leads to a new tweet... of course I need to at some useR... Yihui should be the best choice 😛

Not sure what has happened during the night... when I wake up next morning, they are almost sold out (I listed 10!). Well... then the painful shipping process comes. Thanks to the fantastic e-packet tool(http://shippingtool.ebay.cn), it was pretty convenient to complete shipping online. OK, the postman will take care of them. Goodbye, my cards...

The special benefit is that now I realize how powerful the social network could be. Without spreading information through twitter, it would be much slower if we manually copy and paste the URL in emails. Social network sites control it just in the right way - "word of month" helps customer selects goods based on their reliable information source. Some comments:

Karthik Ram@_inundata 30 May

Totally bizarre #rstats playing cards for sale on @ebay. http://bit.ly/18BmwTg 

Geoff J@geoffjentry 30 May

@_inundata I once bought a "used wife" on @ebay yet somehow this is odder.

Ok...is it that wired?

BTW, the integration of eBay site and twitter is pretty good. Once the link is attached the listing image also appears. See below.2013-06-04 14_11_43-Karthik Ram (_inundata) on Twitter

[Publication] Perhaps...the first publication under BGSE in Chinese

At the end of last month, I was notified that one of my papers co-authored with my previous advisor, Yue Qiao, was accepted. Today I downloaded an electronic version of it and finally confirmed.

That paper is published with the title The Mechanism Evolution and Information Transmission in Online Markets (我国网上交易的机制演化与信息传导) , at the Journal of Zhongnan University of Economics and Law, 2012, 192 (03). At the moment when we submitted the paper, I was studying at the Barcelona Graduate School of Economics, so interestingly the institution behind my name is BGSE in the published version.

I should say it is an old paper - and I have waited for three years to get it published. It is not a short time period - as I have graduated and have already changed a job. On the other hand, the paper is about mechanisms in online C2C market (Taobao.com as the context), and now I am working at eBay and am committed to C2C behavior analysis. Sounds like a regression, right?

Perhaps it is the version reason why I chose eBay immediately right after I got their offer. Theories need to be examined in the real market environment, and eBay is exactly the right place to do this! I have no reason not to be excited about working here. As the theoretical research is accepted, I should spend more time on the empirical part now. Hopefully, these years of knowledge gaining and work experience will enhance my analytical thinking ability and get a fruitful result afterwards.

I'm going on the way, and there is no word called "give up" in my dictionary.

The print version of this paper in Chinese can be download here: Mechanism_evolution_C2C.pdf