Rectangles – Intersection Study

Have you ever walk into a job interview, and were asked to design a program to find if 2 rectangles intersect with each other or not? This apparently is a common “technical” question in a job interview. I do agree that it is an interesting question to evaluate your...

Amazon Alexa on Raspberry Pi

I’m doing a number of projects with the Raspberry Pi.  The latest? I just got Amazon Alexa running on my Raspberry Pi and respond to the wake word “Alexa”.  This is all base on the Alexa AVS Sample App, provided by Amazon. Ready to setup it up? So what...

Scrum Overview

What is Scrum? Scrum is a popular project management framework that uses an iterative and incremental methodology in Agile Software Development. Fun Fact Do you know what the word scrum really mean?  Here is a quote from a dictionary: Scrum – an ordered formation of players, used to restart...

Raspberry Pi 3 – Overview

I recently ordered a Raspberry Pi 3 to evaluate it for both home automation and education purpose.  It is quite an amazing piece of hardware for under $40, and there are tons of open source software available. This is what it looks like when it arrives, it comes in...

Bubble Sort

Sorting algorithm is probably one of the first thing we learn when we study computer science.  My goal is to try to provide the simplest tutorial for you that hopefully will inspire you to think in simple way, and learn the underlying data structure and algorithm. What is bubble...

Java Modifiers

With the variety of programming languages out there, and each one of them may have a slightly different implementation on their syntax and behavior. It is kind of hard to remember them all, so it will be very helpful to have some quick cheat sheet that will provide guideline...

Commonly Used SQL in 1 page

SQL

SQL (Structured Query Language) has been around for many years and is a very useful tool to access data in small or large scale.  If you are like me, that may not be using SQL everyday, but need to use it once in a while.  What I like to...

A Simple HTML Page

The internet, also known as the World Wide Web, started to really take shapes in the 1980s, and basically has exploded into all aspects in our society. We can find all kind of information in the internet,  we can also interact with it, we shop online, we pay our...

Data Types in R

R

Data Types in R take on an interesting twist in contrast to other traditional programming languages like Java and C. In R, the variables are not “declared” with any data type, the variables are assigned some values and the values itself will determine the data type of the variable....

Easy web access log processing with R

R

I recently had a need to diagnose a problem in my web site, so I wanted to do some analysis of the raw access log file.  There are many out-of-the-box analytical utility available but none of them allows me to drill down to the access pattern in more details....