1/17/11

Working with DOM , nodes and Objects (part 1) : Adding Nodes

JavaScript is an Object Oriented Programming (OOP) language.

An OOP language allows you to define your own objects and make your own variable types.

Note that an object is just a special kind of data. An object has properties and methods.

The HTML DOM is a W3C standard and it is an abbreviation for the Document Object Model for HTML.


The HTML DOM defines a standard set of objects for HTML, and a standard way to access and manipulate HTML documents.


1/14/11

Signal Program using parent-child in UNIX

Let us now write a program that communicates between child and parent processes using kill() and signal().

fork() creates the child process from the parent. The pid can be checked to decide whether it is the child(==0) or the parent (pid = child process id).

The parent can then send messages to child using the pid and kill().

The child picks up these signals with signal() and calls appropriate functions. 


Two processes comunicating via shared memory in UNIX

We develop two programs here that illustrate the passing of a simple piece of memery (a string) between the processes if running simulatenously:
server.c
-- simply creates the string and shared memory portion.
client.c
-- attaches itself to the created shared memory portion and uses the string (printf).


1/13/11

Computer graphics : Hidden Surface Elimination

BACKFACE DETECTION: 
In a solid object, there are surfaces which are facing the viewer (front faces) and there are surfaces which are opposite to the viewer (back faces).

These back faces contribute to approximately half of the total number of surfaces. Since we cannot see these surfaces anyway, to save processing time, we can remove them before the clipping process with a simple test.


1/11/11

UML : Interaction Diagrams with Example

  • An interaction diagram is a graphical representation of how objects interact with one another in a scenario.
  • They capture the behavior of a single use case, showing the pattern of interaction among objects.
  • Objects communicate in an interaction diagram by sending messages.
  • Sending a message typically corresponds to invoking a method or function, where the message name is the name of the method.
  • A message may carry data as parameters being passed.


1/10/11

UML : StateChart Diagram with Example

This is a concept in Object Oriented Software Engineering, which is used to describe the behavior of the system.


State diagrams require that the system described is composed of a finite number of states; sometimes.


The below is an state chart diagram of  An Airline reservation system. I hope this helps people to solve their doubt about State Chart Diagram. For Interaction Diagram