Showing posts from January, 2010

FW: Apache Hama in academic paper

HAMA: An Efficient Matrix Computation with the MapReduce Framework

Sangwon Seoyz, Edward J. Yoon, Jae-Hong Kimy, Seongwook Jiny, Jin-Soo Kimx and Seungryoul Maengy
y Computer Science Division, Korea Advanced Institute of Science and Technology (KAIST)
z Computer Science Division, Berlin University of Technology (TU Berlin)
x School of Information and Communication, Sungkyunkwan University, South Korea
User Service Development Center, NHN Corp., South Korea
fswseo, jaehong, swjin,,,


Various scientific computations have become so complex, and thus computation tools play an important role. In this paper, we explore the state-of-the-art framework providing high-level matrix computation primitives with MapReduce through the case study approach, and demonstrate these primitives with different computation engines to show the performance and scalability. We believe the opportunity for using MapReduce in scientific compu…

comScore Reports Global Search Market Growth of 46 Percent in 2009

Google Sites Accounts for Two-Thirds of 131 Billion Searches Conducted Worldwide in December while Introduction of Bing Helps Microsoft Post Significant Gains During the Year

Reston, VA, January 22, 2010 – comScore, Inc. (NASDAQ: SCOR), a leader in measuring the digital world, today released a study on growth in the global search market in 2009. The study revealed that the U.S. remains the largest search market worldwide, while Google Sites retains a commanding position in the global search market.
“The global search market continues to grow at an extraordinary rate, with both highly developed and emerging markets contributing to the strong growth worldwide,” said Jack Flanagan, comScore executive vice president. “Search is clearly becoming a more ubiquitous behavior among Internet users that drives navigation not only directly from search engines but also within sites and across networks. If you equate the advancement of search with the ability of humans to cultivate information, then …

Responding to JSON in your server-side JSP script

I wanted to implement some open API for JSON clients. It took me an two days to finish it, Javascript&JSP gives me a pain in the neck. :(

Below is the example code to responding to JSON in a server-side JSP script. It shows how to set up the JSON text, HTTP header and jsoncallback. I hope you don't waste time.

<%@ page language="java" import="net.sf.json.JSONObject" %> <%@page import="java.util.*" %> <% response.setContentType("application/json"); response.setCharacterEncoding("UTF-8"); JSONObject object=new JSONObject(); object.put("key", "value"); String jsoncallback = request.getParameter("jsoncallback"); response.getWriter().println(jsoncallback + "(" + object.toString()+");"); %>

CentOS - install rpmforge yum repo

Install DAG GPG key

wget # download DAG GPG key rpm --import RPM-GPG-KEY.dag.txt # import the key rm RPM-GPG-KEY.dag.txt # clean up after ourselves
Install yum-priorities

yum install yum-priorities
Download and install package (i386 - 32bit)

wget rpm -Uhv rpmforge-release-0.3.6-1.el5.rf.i386.rpm # install the rpmforge yum repo rm rpmforge-release-0.3.6-1.el5.rf.i386.rpm # clean up after ourselves
Download and install package (x86_64 - 64bit)

wget rpm -Uhv rpmforge-release-0.3.6-1.el5.rf.x86_64.rpm # install the rpmforge yum repo rm rpmforge-release-0.3.6-1.el5.rf.x86_64.rpm # clean up after ourselves

A short unique string identifier for shorten URL

How to shorten URLs? As far as you know, there is a lot of Short URL Redirection Services, such as "", which used to convert a long url to some short url.

Its Mechanism seems simple. The sequential key for long URL is enough.
For example, the "Wa0e" is the key of ""
for "".
The mod_rewrite module could be used to remove file extension and parameters (e.g., short.php?key=Wa0e)

Key looks like a random string, but I guess it's just a sequential key. Because, that way is simple, and same with total number of random combination in conclusion.

How to generate sequential key? Below is my example code.

INDEX.length is 62. So, (62^4 -1) URLs could stored in the combination of four ciphers.

private static String[] INDEX = new String[] { "0", "1", "2", "3", "4", "5", "6", "…

Get year from java.util.Date

import java.text.SimpleDateFormat; import java.util.Date; public class Test { public static void main(String args[]) throws Exception { Date date = new Date(); SimpleDateFormat simpleDateformat = new SimpleDateFormat("yyyy"); System.out.println("Year: " + simpleDateformat.format(date)); } }

Linux Tip, XawTV and Audio driver problem

I recently upgraded my computer by replacing the motherboard, CPU, memory and video card.

Motherboard: GA-P43-ES3G
CPU: Intel(R) Core(TM)2 Quad CPU Q8300 @ 2.50GHz
Audio: Realtek ALC 888
Memory: 2 GB
Video card: NVIDIA GeForce 9600 GT
TV card: VAST bt878
OS: Fedora 12

Damn fast!!. BTW, I just wanted to see TV but It was really hard to solve. :( If you have same problem with Realtek ALC 888 and VAST bt878, below will be helpful for you!

1) XawTV - can't load any font

$ xawtv .... WARNING: No DGA support available for this display. /dev/video0 [v4l2]: no overlay support v4l-conf had some trouble, trying to continue anyway Warning: Cannot convert string "7x13bold" to type FontStruct Warning: Missing charsets in String to FontSet conversion Warning: Missing charsets in String to FontSet conversion Warning: Missing charsets in String to FontSet conversion Oops: can't load any font
I installed zvbi-fonts to solve this issue. but didn't solved. So, I tried to instal…