Singleton pattern is a well-known pattern in programming. Double-checked locking is an implementation of singleton pattern which is intended to be thread-safe. However it is found that this method is broken, unless memory barrier is used which may has problem of portability.

In this article, I am going to present an alternative to double-checked locking ...

An excellent article about android. You shouldn't use android task killers, as they will cause system instability and more battery drain. Android version 2 or above doesn't need them.

You should use something like watchdog to see what apps is eating up resources and misbehave and end them instead.

A new kind of camera, which allows you to take the photo now, and focus later at any point you like. There is demo in the web.

The principle is that, you record not the sum of all the light cones, but the individual light ray's vector direction. So that you can focus to any plane by ray tracing method.

44 Challenging problems. Many are quite difficult, and tests if your physics understand is solid enough!

A gnome style to make eclipse and other applications look more compact, and save more screen space.

Unblock me is a puzzle game in iphone. It's originated from rush hour. I am interested in solving the board game using computer. I can enter the board configuration into the computer one by one, but I would like to do it automatically. With image processing capatibability in Mathematica, the process can be done rather easily by taking screenshot.

Is it possible to add garbage collector to MathOO which is practical?

In Mathematica, variables with downvalues will not be collected even it has the attribute "temporary".

Since MathOO makes extensive use of downvalues for both class and object, is it possible to overcome ...

A package is released as open source project in GoogleCode/MathOO-packages. The aim of the project is to provide basic utilities and basic classes using MathOO, so that you can use it in an object oriented way. In the initial release, 1.0b, a dictionary class (associated array) is provided.

This document is a documentation of the dict class in MathOO-packages. Basically it behaviors very similarly to Python dict.

This is a basic tutorial about using MathOO, the internal structure of MathOO, and how MathOO works.