Petit Jardin: August 2011

Thursday, August 25, 2011

latex argmax and argmin

Latex does not have built-in support for argmax and argmin.

The following are two tricks that works for me.

\underset{x}{\operatorname{argmax}}{content}

Cheers!

Convert ArrayList to Array in Java. ArrayList to Array. Java Collection

A lot of time I have to convert ArrayList to Arrays in my Java program. Although this is a simple task, many people don’t know how to do this and end up in iterating the java.util.ArrayList to convert it into arrays. I saw such code in one of my friends work and I thought to share this so that people don’t end up writing easy thing in complicated way.

ArrayList class has a method called toArray() that we are using in our example to convert it into Arrays.

Following is simple code snippet that converts an array list of countries into string array.

List list = new ArrayList;

list.add("India");

list.add("Switzerland");

list.add("Italy");

list.add("France");

String [] countries = list.toArray(new String[0]);

So to convert ArrayList of any class into array use following code. Convert T into the class whose arrays you want to create.

List list = new ArrayList;

T [] countries = list.toArray(new T[list.size()]);

Convert Array to ArrayList

We just saw how to convert ArrayList in Java to Arrays. But how to do the reverse? Well, following is the small code snippet that converts an Array to ArrayList:



String[] countries = {"India", "Switzerland", "Italy", "France"};

List list = new ArrayList(Arrays.asList(countries));

System.out.println("ArrayList of Countries:" + list);

Converting UTM coordinates into latitude and longitude coordinates

The coordinates used in the raw GPS data are sometimes in the UTM (Universal

Transverse Mercator coordinate system) format.

There is a need to convert them into into latitude and longitude coordinates for reverse-geocoding with Google Map API.

There may be many ways of doing the conversion. The following are two ways:

The method introduced by Salkosuo (java lib)http://www.ibm.com/developerworks/java/library/j-coordconvert/
Postgis extension provides in-database conversion function.

Kill Processes From The Command Prompt In Windows 7

A few processes start with Windows implicitly by default.

One way to remove these processes is to use msconfig in run.

Then tick off any program that should not start up with Windows.

But some processes do stay even the first way is applied. Use these commands to kill them. (Caution: do know what you are doing before doing it)

In CMD window:

1. Enter command 'tasklist'

2. To kill a process with a name. E.g. To kill firefox, enter the command 'Taskkill /IM firefox.exe /F', /F means by force.

3. To kill a process with PID, enter 'Taskkill /PID 364 /F'

Tuesday, August 16, 2011

How to remove ^M from file using VI

Sometimes DOS files have "^M" at the end of each line, which causes problem for perl to read lines correctly.

We can use VI to remove these annoying ^M.

=============Using VI================

Type the following command at the terminal.

vi file_name.txt

Basically vi is the name of a text editor under linux/mac.

After issuing this command, you should be able to see the command window showing the content of the file.

Next step is to remove the annoying ^M at the end of each line.

Type the following command in VI editor. Do not miss the semi-colon at the begining.

:%s/[ctrlkey+v and ctrl-key+M]/\r/g

You should be able to see the following at the left-bottom corner of the command window:

:%s/^V^M/\r/g

The command above is meant to replace ^M with a new line symbol "\n".

Press enter and wait for a while for every occurrence of ^M to be replaced.

Depending on the size of your file, it can take a while and the screen appears frozen.

When the replacing is done, type the following command to save and exit from VI.

Good luck!

Thursday, August 4, 2011

Database conferences

Conference	Conf. Dates	Paper Deadline	Notification	Location
SIGMOD 2012	20/05-25/05	01/11/2011	14/02/2012	Scottsdale, Arizona, USA
VLDB 2012	27/08-31/08	1st day per month	May 19, 2012	Istanbul， Turkey
ICDE 2012@Arlington, US	April 01-05, 2012	July 19, 2012	Sep 27, 2012	ICDE 2012
EDBT 2012@Berlin	21/03-25/03	Oct 6 2011	-	EDBT 2012
MDM 2012@London	06/06-09/09	-	-	London
SSTD 2011@Minneapolis	Aug 24-26, 2011	25/02/2011	Apr 29, 2011	-
DASFAA 2012	02-05/04/2012	30/09/2011		Pusan /South Korea
DEXA 2011 @ Toulouse, France	29/08-02/09/2011	-	-	DEXA 2011
SSDBM @ Portland, Oregon	Jul 20-22, 2011	January	Mar 28, 2011
ICDM @ Vancouver, Canada	Dec 11-14, 2011	Jun 17, 2011	Sep 16, 2011	-

How to Be a Successful PhD Student (zz)

Getting a Ph.D. can be a very rewarding experience both personally and professionally. Being a successful Ph.D. graduate student, however, can be more complicated than some expect. Being a Ph.D. student means finding balance in several areas of life, working hard, making connections with others and cultivating certain personality traits necessary to succeed in your program of choice.

Instructions

- 1
  Build a relationship with a good supervisor, mentor or adviser early. You should preferably choose someone who is well-supported with grants or has tenure in order to eventually make use of the resources he has. Consult with your supervisor for professional guidance and advice. Don't be afraid to switch supervisors if you find that you have trouble working with the one you have.
- 2
  Prepare to work very hard for long periods of time. Most Ph.D. students seldom stop working, even through weekends. Getting a Ph.D. is not supposed to be easy; find a routine and a schedule that works for you as early as you can.
- 3
  Take care of yourself. Due to the heavy workload of the basic Ph.D. program, it is easy to let your health and well-being take a backseat to other priorities. Try to take some weekends or holidays off. Despite the heavy course load, you will need to learn when you need a short break in order to avoid burning out. Exercise when you can. Always eat right, even during late-night study sessions.
- 4
  Connect with other graduate students. The best people to get to know during your Ph.D. are people who know exactly what you are going through because they are going through it at the same time. Arrange for study dates, coffee breaks or days out.
- 5
  Begin cultivating an expertise in your field early. Start by reading all of the literature you can in your field of specialization. It is difficult to add anything to the field you study if you don't know what is already out there. Also, try going to conferences in your field to find out what questions or research currently predominate the field.
- 6
  Research, write and publish. Getting a Ph.D. usually means that you have committed yourself to a research-based, academically focused career path. This means that you too must research, explore, pose questions, find answers and share them with the rest of your colleagues. Start by narrowing down your field of interest and doing some extensive research in that area. Hire a librarian to help you find all the materials you need. Enlist your supervisor to help you formulate ideas and get your writing ready for scholarly journal publication.
- 7
  Find ways to motivate yourself when you are feeling burnt out or are pulling an all-nighter; using a rewards system or reminding yourself of your professional goals are two such ways to do so.
- 8
  Be prepared to compete with your friends on a certain level. Your superiors will naturally compare you to them; try not to let this fact interfere with your personal life.

Petit Jardin