Aakar Tech Blog

How Java Program Run ?

aakar@aakarpost.com — Sat, 24 Oct 2009 06:49:00 +0000

Q.How does a typical Java applet run? Explain with suitable illustrations making references to the running of a java program.

Ans:A java program goes through three phases – coding, compilation, and execution in order to run. At first, a program is created called “source code” with an extension .java. Then, the compiler creates the byte codes and stores in the same filename with '.class' extension. Next, the Class Loader and Byte code Verifier loads the file into memory and verifies the byte codes. In the final stage, the Java Virtual Machine (JVM) translates the program into machine language and executes the program.

Fig.1 : Steps to run a Java Program

An applet is a program written in the Java programming language that can be included in an HTML page, much in the same way an image is included in a page. When you use a Java technology-enabled browser to view a page that contains an applet, the applet's code is transferred to your system and executed by the browser's Java Virtual Machine (JVM).

An applet must be a subclass of the java.applet.Applet class. The Applet class provides the standard interface between the applet and the browser environment.Swing provides a special subclass of the Applet class called javax.swing.JApplet. The JApplet class should be used for all applets that use Swing components to construct their graphical user interfaces (GUIs).

Applets are compiled Java programs designed to be small, fast, and easily transferrable over network resources. Applets are ideal for the Web because they leverage browser features which decrease file size, increase download speed, and simplify the programming. Applets, however, have limitations which full-blown Java applications do not have. The limitations of applets can be described as follows:

Applets have limited file access
Applets have limited network access

Every Java applet is a graphical user interface on which we can place GUI components using the different techniques. We begin with a simple applet that draws “Welcome to Java Programming” on the applet. This applet executing in two applet containers- the ‘applet viewer’ and the ‘Microsoft Internet Explorer web browser’

Example of applet that draws a string:

import java.awt.Graphics; //program uses class Graphics

import javax.swing.JApplet; //program uses class JApplet

public class WelcomeApplet extends JApplet

{

//draw text on applet’s background

Public void paint (Graphics g)

{

// call superclass version of method paint

Super.paint (g);

//draw a String at x-coordinate 25 and y-coordinate 25

g.drawString (“Welcome to Java Programming!”, 25, 25);

} //end method paint

} //end class WelcomeApplet

Creating the Applet Class:-

Line 1 imports class Graphics to enable the applet to draw graphics, such as lines, rectangles, ovals and strings of characters. Class JApplet (imported at line 2) from package javax.swing is used to create applets. As with applications, every Java applet contains at least one public class declaration. An applet container can create only objects of classes that are public and extend JApplet (or the Applet class from early versions of Java). For this reason, class WelcomeApplet (line 3-14) extends JApplet.

An applet container expects every java applet to have methods named init, start, paint, stop and destroy, each of which is declared in class JApplet. Each new applet class we create inherits default implementations of these methods from class JApplet. These methods can be overridden (redefined) to perform tasks that are specific to our applet.

When an applet container loads class WelcomeApplet, the container creates an object of type WelcomeApplet, then calls three of the applet’s methods. In sequence, these three methods are init, start and paint. If we do not declare these methods in our applet, the applet container calls the inherited versions. The superclass methods init and start have empty bodies, so they do not perform any tasks. The superclass method paint does not draw anything on the applet.

We might wonder why it is necessary to inherit methods init, start and paint if their default implementations do not perform tasks. Some applets do not use all three of these methods. However, the applet container does not know that. Thus, it expects every applet to have these methods, so that it can provide a consistent start-up sequence for each applet. This is similar to applications always starting execution with main. Inheriting the ‘default’ versions of these methods guarantees that the applet container can execute each applet uniformly. Also, inheriting default implementations of these methods allows the programmer to concentrate on defining only the methods required for a particular applet.

Overriding Method paint for Drawing:-

To enable our applet to draw, class WelcomeApplet overrides method paint (lines 6-13) by placing statements in the body of paint that draw a message on the screen. Method paint receives a parameter of type Graphics (called g by convention), which is used to draw graphics on the applet. We do not call method paint explicitly in an applet. Rather, the applet container calls paint to tell the applet when to draw, and the applet container is responsible for passing a Graphics object as an argument.

Line 10 calls the superclass version of method paint that was inherited from JApplet. This statement should be the first statement in every applet’s paint method. Omitting it can cause subtle drawing errors in applets that combine drawing and GUI components.

Line 12 uses Graphics method drawString to draw Welcome to Java Programming! on the applet. The method receives as arguments the String to draw and the x-y coordinates at which the bottom-left corner of the String should appear in the drawing area. When line 12 executes, it draws the String on the applet at the coordinates 25 and 25.

Executing an Applet in the appletviewer:-

As with application classes, we must compile an applet class before it can execute. After creating class WelcomeApplet and saving it in the file WelcomeApplet.java open a command window, change to the directory in which we saved the applet class declaration and compile class WelcomeApplet.

Recalling that applets are embedded in web pages for execution in an applet container (appletviewer or a browser); before we can execute the applet, we must create an HTML document that specifies which applet to execute in the applet container. This show a simple HTML document- WelcomeApplet.html – that loads the applet defined as below into an applet container.

Lines 2 & 3 specify an applet element that tells the applet container to load a specific applet and defines the size of the applet’s display area (its width and height in pixels) in the applet container. Normally, the applet and its corresponding HTML document are stored in the same directory on disk. When an applet container encounters an HTML document that contains an applet, the applet container automatically loads the applet’s .class file (or files) from the same directory on the computer in which the HTML document resides.

The applet element has several attributes. The first attributes in line 2, code = ”WelcomeApplet.class”, indicates that the file WelcomeApplet.css contains the compiled applet class. The second and third attributes in line 2 indicate the width (300) and the height (45) of the applet in pixels. The tag (line 3) terminates the applet element that began at line 2.

Executing an Applet in Web Browser:-

This sample program execution demonstrate WelcomeApplet executing in the appletviewer and in Microsoft Internet Explorer web browser. To execute an applet in Internet Explorer, perform the following steps:

Select Open…from the File menu.

In the dialog box that appears, click on Browse…button.

In the dialog box that appears, locate the directory containing the HTML document for the applet we wish to execute.

Select the HTML document.

Click the Open button.

Click the OK button.

Applet Life-Cycle Methods:-

Now that we have created an applet, let’s consider the five applet methods that are called by the applet container from the time the applet is loaded into the browser to the time that it is terminated by the browser. These methods correspond to various aspects of an applet’s life cycle. These methods, which are inherited int our applet classes from class JApplet. Below specifies when each method gets called and explains its purpose. Other than method paint, these methods have empty bodies by default. If we would like to declare any of these methods in our applets and have the applet container call them, we must use the method headers. If we modify the method headers (e.g., by changing the method names or by providing additional parameters), the applet container will not call our methods. Instead, it will call the superclass methods inherited from JApplet.

public void init()

It is called once by the applet container when an applet is loaded for execution. This method initializes an applet. Typical actions performed here are initializing fields, creating GUI components, loading sounds to play, loading images to display and creating threads.

public void start()

It is called by the applet container after method init completes execution. In addition, if the user browsers to another website and later returns to the applet’s HTML page, method start is called again. The method performs any tasks that must be completed when the applet is loaded for the first time and that must be performed every time the applet’s HTML page is revisited. Actions performed here might include starting an animation or starting other threads of execution.

public void paint (Graphics g)

It is called by the applet container after methods init and start. Method paint is also called when the applet needs to be repainted. For example, if the user covers the applet with another open window on the screen and later uncovers the applet, the paint method is called. Typical actions performed here involve drawing with the Graphics object g that is passed to the paint method by the applet container.

public void stop()

This method is called by the applet container when the user leaves the applet’s web page by browsing to another web page. Since it is possible that the user might return to the web page containing the applet, method stop performs tasks that might be required to suspend the applet’s execution, so that the applet does not use computer processing time when it is not displayed on the screen. Typical actions performed here would stop the execution of animations and threads.

public void destroy ()

This method is called by the applet container when the applet is being removed from memory. This occurs when the user exits the browsing session by closing all the browser windows and may also occur at the browser’s discretion when the user has browsed to other web pages. The method performs any tasks that are required to clean up resources allocated to the applet.

References:

How to Learn Java Program, Deitel and Deitel

http://java.sun.com/applets/

http://faculty.inverhills.mnscu.edu/speng/cs1126/Notes/Chapter01/JavaDE_files/image002.jpg

Language Paradigms

aakar@aakarpost.com — Tue, 06 Oct 2009 03:17:00 +0000

Language Paradigms:

There are four basic computational models which describe the most programming language today. Imperative, applicative, rule based and object oriented are the basic computational models.

Imperative Languages:

Imperative or procedural languages are command-driven or statement oriented language. The basic concept is the machine state, the set of all values for all memory locations in the computer. A program consists of a sequence of statements and the execution of each statement causes the computer to change the value of one or more locations in its memory. i.e. to enter a new state.

The syntax of such languages generally has the form:

statement1;

statement2;

…

Imperative languages are defined according to the characteristics that they display.

By default, statements (commands) are executed in a step-wise, sequential, manner.
As a result order of execution is crucial.
Destructive assignment - the effect of allocating a value to a variable has the effect of destroying any value that the variable might have held previously.
Control is the responsibility of the programmer - programmers must explicitly concern themselves with issues such as memory allocation and declaration of variables.
The imperative paradigm is the most established paradigm.
It is much more in tune with the computer community's way of thinking.
Imperative programs tend to run much faster than many other types of program.
Programmers are prepared to sacrifice some of the advanced features and programming convenience generally associated with higher level languages in exchange for speed of execution.
Most modern imperative languages are designed explicitly for compilation.
Older imperative languages (e.g. BASIC and APL), and some very high level imperative-languages (e.g. ICON) are interpreted.

Example:

C, C++, FORTRAN, Algol, PL/I, Pascal, Ada, Smalltalk and COBOL are supported by this model. This model follows from the hardware of the conventional computer that executes instructions sequentially.

Applicative Languages:

An alternative view of the computation performed by a programming language is to look at the function that the program represents rather than just the state changes as the program executes, statement by statement. We can achieve this by looking at the desired result rather than at the available data. Languages that emphasize this view are called applicative or functional language.

Rather than looking at the successive machine states of a computation, we consider the successive functional transformations that we must make on data to arrive at our answer. The syntax of such languages generally is similar to:

functionn (…function2 (function1 (data))…)

LISP and ML are two functional languages in this book that support this model.

Rule Based Languages:

Rule based languages execute by checking for the presence of a certain enabling condition and when present executing an appropriate action. The most common rule-based language is Prolog, also called a logic programming language, because the basic enabling conditions are certain classes of predicate logic expressions.

Execution if a rule-based language is similar to an imperative language except that statements are not sequential. Enabling conditions determine the order of execution. The syntax of such languages generally is similar to the following:

enabling condition1 action1

enabling condition2 action2

….

enabling conditionn actionn

The common business application of decision tables is a form of rule-based programming. In this case, enabling conditions on data are governed by the presence or absence of enabling data values in a data record. BNF parsing techniques and tools like YACC to parse programs are rule-based techniques that use the formal syntax of the program as the enabling condition.

Object-oriented programming:

Object oriented programming is becoming an increasingly important computational model. In this case, complex data objects are built, then a limited set of functions are designed to operate on those data. Complex objects are designed as extensions of simpler objects, inheriting properties of the simpler object. By building concrete data objects an object-oriented program gains the efficiency of imperative languages. By building classes of functions that use a restricted set of data objects, we build the flexibility and reliability of the applicative model.

Spaghetti code:

Spaghetti code is a pejorative term for source code which has a complex and tangled control structure, especially one using many GOTOs, exceptions, threads, or other "unstructured" branching constructs. It is named such because program flow tends to look like a bowl of spaghetti, i.e. twisted and tangled. Spaghetti code can be caused by several factors, including inexperienced programmers and a complex program which has been continuously modified over a long life cycle. Structured programming greatly decreased the incidence of spaghetti code.

Example:

10 i = 0

20 i = i + 1

30 PRINT i; " squared = "; i * i

40 IF i >= 10 THEN GOTO 60

50 GOTO 20

60 PRINT "Program Completed."

70 END

Structured Code:

Structured code is code stored in a data structure instead of in typical text files. Text file source code must follow restrictive syntax rules in order for the source code to be parsed by a compiler into a structure called the abstract syntax tree (AST). Structured source code, however, has much less restrictive syntax rules because it is created and edited by structured editors directly on the abstract syntax tree and the parsing step is bypassed. This also separates the notation from the software content, which in turn increases substantially the variety of possible notations available for domain experts and programmers to express their intentions.

Example: (same as above example).

FOR i = 1 TO 10

    PRINT i; " squared = "; i * i

NEXT i

PRINT "Program Completed."

END

References:

i. Pratt, Terrence and Zelkowitz, Programming Languages Design and Implementation, Pearson Education, 4^th edition.

ii. http://www.csc.liv.ac.uk/~grant/Teaching/COMP205/intro.html

iii. http://en.wikipedia.org/wiki/Spaghetti_code

iv. http://intentsoft.com/technology/glossary.html

Operating Environment

aakar@aakarpost.com — Tue, 15 Sep 2009 03:01:00 +0000

i. Operating or Target Environment:

The hardware that supports a language has a great impact on language design. Languages, as a mean to solve a problem, are part of the overall technology that is employed. The external environment supporting the execution of a program is termed its operating or target environment.

In computing, an operating environment is an environment in which users run application software, whether by a command-line interface or a graphical user interface. An operating environment is usually not a full operating system but is a form of middle ware that rests between the OS and the application.

ii. Host Environment:
The environment in which a program is designed, coded, tested and debugged is called host environment. Host Environment may be different from the operating environment in which the program ultimately used.

A quiet host environment is important because it protects enclosures used as narration environments from outside noise. It is also the work site for monitors and frequently the work site for reviewers. The task of monitoring and reviewing requires continuous, concentrated attention to acoustical details, and noise in the host environment affects how well that task can be accomplished. The host environment should be free from airborne noise and structure-borne noise.

iii. Batch Environment:
The earliest and simplest operating environment consists of external files of data. A program that takes a set of data files as input processes the data and produces a set of output data files. This operating environment is termed as batch-processing. In batch processing, the input data are collected in batches on files and are processed in batches by the program.

Languages such as FORTRAN, COBOL, and Pascal were initially designed for batch-processing environments, although they may be used now in interactive or in an embedded-system environment. The 80-column punch card which is developed by Herman Hollerith is used in the 1890 U.S census, was the ubiquitous sign of computing in the 1960's.

In a batch processing environment, an error that terminates execution of the program is acceptable but costly because often the entire run must be repeated after the error is corrected. In this environment, no external help from the user is immediately handling or correcting the error is possible. Thus, the error and exception handling facilities of the language emphasize error/exception handling with in the program so that the program may recover from most errors and continue processing without terminating.

Batch processing environment is the lack of timing constraints on a program. The language usually provides no facilities for monitoring or directly affecting the speed at which the program executes.

iv. Interactive Environment:
In an Interactive Environment, a program interacts directly with a user at a display console during its execution, by alternately sending output to the display and receiving input from the keyboard or mouse. Word processing systems, spreadsheets, video games, database management systems are examples which is used in Interactive Environment.

The characteristics of interactive I/O are sufficiently different form ordinary file operations that most languages designed for a batch processing environment experience so difficulty in adapting to an interactive environment.

Error handling in an interactive environment is given different treatment. If bad input data are entered from a keyboard, the program may display an error message and ask for a correction from the user. Language features for handling the error within the program are of lesser importance. Unlike batch processing, termination of the program in response to an error is usually not acceptable.

Interactive programs must often utilize some notion of timing constraints. An interactive program that operates so slowly that it cannot respond to an input command in a reasonable period is often considered unusable.

v. Embedded-system Environment:
A computer system that is used to control part of a larger system such as an industrial plant, an aircraft, a machine tool, an automobile, or even your toaster is termed an Embedded Computer System.

Programs written for embedded systems often operate without an underlying operating system and without the usual environment of files and I/O device. Instead, the program must interact directly with nonstandard I/O devices through special procedures that take account of the peculiarities of each device. Access to special devices is often provided through language features that give access to particular hardware registers, memory locations, interrupt handlers, or subprograms written in assembly or other low-level languages.

Error handling in embedded systems is of particular importance. Ordinarily, each program must be prepared to handle errors internally, taking appropriate actions to recover and continue.

Embedded systems almost always operate in real time. i.e. the operation of larger system within which the computer system is embedded requires that the computer system be able to respond to inputs and produce outputs within tightly constrained time intervals.

Finally, an embedded computer system is often a distributed system composed of more than one computer. The program running on such a distributed system is usually composed of set of tasks that operate concurrently, each controlling or monitoring one part of the system.

Compiler vs. Interpreter

aakar@aakarpost.com — Mon, 14 Sep 2009 01:20:00 +0000

A compiler converts the entire program into executable code before running, when running the program only the executable version of the code is running.

An interpreter converts the code during run time; it converts the code 1 line at a time at the time that it is running.

An interpreter translates some form of source code into a target representation that it can immediately execute and evaluate. The structure of the interpreter is similar to that of a compiler, but the amount of time it takes to produce the executable representation will vary as will the amount of optimization.

Compiler characteristics:

* spends a lot of time analyzing and processing the program
* the resulting executable is some form of machine- specific binary code
* the computer hardware interprets (executes) the resulting code
* program execution is fast

Interpreter characteristics:

* relatively little time is spent analyzing and processing the program
* the resulting code is some sort of intermediate code
* the resulting code is interpreted by another program
* program execution is relatively slow

A programming language can be made into a working program either by Interpretation or compilation. There isn't a Compiler and an Interpreter language. But any code any be made into a program by compiling it using an Interpreter (checks a line of your code at a time and stops at errors) or compiler (checks the entire code at a time and displays all errors at the end).

Examples:
BASIC is a teaching language, it is usually interpreted. FORTH (for radio telescopes) and LOGO (for floor crawlers) are other languages which are usually interpreted, since they are robotic.
Languages which are used for commercial programming will nearly always be compiled. C, C++, C# are nearly always compiled, and so is Pascal and all its derivatives (Oberon, Delphi &c.).

Merge Sort

aakar@aakarpost.com — Mon, 06 Apr 2009 04:36:00 +0000

Abstract:

Merge Sort has several advantages on performance. This technique divides the whole data as like divided and conquer method but until two elements in a group. Then solves the divided parts and conquers them. The resulting efficiency of this method is that the division of problem is much less then the previous method, so the recursive call is also less. As a result we have less comparison and less computational time. Merge sort can be implemented in C to sort the file.

Introduction:

Merging is the process of combining two or more sorted files into a third sorted file. In most implementations it preserves the input order of equal elements in the sorted output. It is an example of the divide and conquer algorithmic paradigm. It is also called Divide and Conquer where we divide the problem into a number of sub-problems and then we conquer the sub-problems by solving them recursively. Merge sort can be implemented in C to sort the file. Divide the file into n subfiles of size 1 and merge adjacent pairs of files. We then have approximately n/2 files of size 2. Repeat this process until there is only one file remaining of size n.

Working Mechanism:

Theoretically, a merge sort works as follows:
If the list is of length 0 or 1, then it is already sorted. Otherwise:
Divide the unsorted list into two sublists of about half the size.
Sort each sub list recursively by re-applying merge sort.
Merge the two sublists back into one sorted list.

To sort A [p…r] Divide by splitting into two subarray A [p…q] and A [q+1…r], where q is the half way point of A[p…r].
Conquer by recursively sorting the two subarrays, A [p…q] and A [q+1…r].
Combine by merging the two sorted subarrays A [p…q] and A [q+1…r] to produce a simple sorted array A [p…r].

Example:

Original file:

Pass 1: ↓ ↓ ↓ ↓

Pass 2: ↓ ↓

Pass 3: ↓

Sorted file:

Pseudocode:

Merge (A, p, q, r)
n1 ← q – p + 1
n2 ← r – q

Create arrays, L[1…n1+1] and R[1…n2+1]

for i ← 1 to n1,
do L[i] ← A[p+i-1]
for j ← 1 to n2,
do R[j] ← A[q+j]

L[n1+1] ← ∞
R[n2+1] ← ∞
i ← 1
j ← 1

for k ← p to r
do if L[i] ≤ R[j]
then A[k] ← L[i]
i ← i+1
else
A[k] ← R[j]
j ← j+1

Note: We constructed two auxiliary arrays namely L and R.

Implementation of the algorithm in C:

/* An example of routine that accepts two sorted arrays a and b of n1 and n2 elements, respectively, and merges them into a third array c containing n3 elements. */

void mergearr(int a[], int b[], int c[], int n1, int n2, int n3)
{
int appoint, bpoint, cpoint;
int alimit, blimit, climit;

alimit = n1-1;
blimit = n2-1;
climit = n3-1;
if (n1+n2 ! = n3)
{
printf(“array bounds incompatible/n”);
exit(1);
}
apoint = 0;
bpoint = 0;
for (cpoint = 0; appoint <= alimit && bpoint <= blimit; cpoint++) if(a[appoint] < style="font-weight: bold;">Analysis:

Merge sort is more efficient than other sort for some types of lists if the data to be sorted can only be efficiently accessed sequentially, merge sort is a stable sort as long as the merge operation is implemented properly. In sorting n items, merge sort has an average and worst-case performance of(n log n). If the running time of merge sort for a list of length n is T(n), then the recurrence T(n) = 2T(n/2) + n follows from the definition of the algorithm .
In the worst case, merge sort does approximately (n ⌈lg n⌉ - 2⌈lg n⌉ + 1) comparisons, which is between (n lg n - n + 1) and (n lg n + n + O (lg n)). In the worst case, merge sort does about 39% fewer comparisons than quick sort does in the average case; merge sort always makes fewer comparisons than quick sort, except in extremely rare cases, when they tie, where merge sort’s worst case is found simultaneously with quick sort’s best case.

Types of analysis:

Worst case:
T(n)=maximum time of algorithm of any input size of n.

Average case:
T(n)=expected time of algorithms overall inputs of size n.
Need assumptions of statistical distribution of inputs.

Best case:
Cheat with a slowly algorithm that works fast on some input.

Conclusions:

It is always O(nlogn), it is a very good alternative if the extra memory requirement is not a problem. Array elements with fast comparisons and slow copying seem to slightly penalize merge sort.
O(nlgn) grows more slowly than O(n2).
Therefore merge sort asymptotically beats insertion sort in the worst case.
In practice, merge sort beats insertion sort for n>30 or so.

ADT

aakar@aakarpost.com — Sun, 05 Apr 2009 00:07:00 +0000

ADT is the basic mathematical concept that defines the data type and stands for Abstract Data Type. Formally, ADT can be defined as a set of data values and the associated operations that are precisely specified, independent of any particular implementation.

Value Definition:
The Value definition defines the collection of values from the ADT and consists of two parts: A definition Clause (compulsory) and A Condition Clause (optional).

Operator Definition:
The operator definition consists of three parts: Header, Precondition and Post Condition.

An example of ADT.

abstract typedef <> STRING;

abstract length (s)
STRING s;
postcondition length = = len(s);

abstract STRING concat(s1,s2)
STRING s1,s2;
postcondition concat=s1+s2;

abstract STRING substr(s1, i, j)
STRING s1;
int i, j;
precondition 0 <= i < len(s);
0 <= j <= len(s1) – i;
postcondition substr = = sub(s1,i,j);

abstract pos(s1, s2)
STRING s1,s2;
postcondition

( ( pos = = -1) && (for( i=0; i <= lastpos; i++ ) (s2 <> sub(s1,i,,len(s2) ) ) ) )
| |
( ( pos >= 0) && ( pos <= lastpos) && ( s2 = = sub (str1, pos, len(s2) )

&& ( for( i=1; i sub(s1,i, len(s2) ) ) ) )

What is Programming?

aakar@aakarpost.com — Sat, 04 Apr 2009 11:08:00 +0000

Contrary to popular belief, computers are not clever. Left to itself, a computer doesn’t do anything at all – it won’t show the time, or display what you type on the screen, let alone play a video game. The reason that computers are such useful tools, and give the appearance of cleverness, is that they follow instructions, very accurately, very repetitively, and very quickly. For example, when a computer displays a clock, it does so because it has instructions for how to draw every color and tick mark in the clock face, and every line in the clock’s rotating hands, onto the computer screen.

Programming is the act of giving instructions to a computer so that it knows how to perform an action. Fundamentally, these instructions are a series of numbers – to a computer, everything is numbers – in a kind of code where different numbers represent different instructions. The good news is that programmers don’t have to learn all these numbers (the ‘machine code’), because they can write their instructions in a more intuitive form, and then have the computer convert these instructions into machine code.

The intuitive or human-readable form of instructions is called a computer language. Like languages in the real world, there are dozens of computer languages. Some are for specialized tasks and others are more general-purpose. What all programming languages have in common is that they enable programmers to create instructions for a computer without having to learn the computer’s numeric machine code.

Author: Rich Tebb

Creating modern music from vintage computers

aakar@aakarpost.com — Sat, 14 Mar 2009 01:29:00 +0000

Matthew Applegate, aka Pixelh8, is a leading light of the "chiptune" scene - music made using vintage home computers. Now he is embarking on his most ambitious project to date, holding two concerts consisting of music made on some of the oldest and rarest computers in the world at the UK's National Museum of Computing at Bletchley Park, the second world war code-breaking centre. Sumit Paul-Choudhury talked to him ahead of the performances of his show, called Obsolete?.

Listen to Chocolate Milk, from the album The Boy With The Digital Heart (2007, Hidden Youth Records UK)

Listen to Math, part of Pixelh8's new show Obsolete? (2009, Hidden Youth Records UK)

How did you get into this music?

I was in an REM covers band in the late 1990s, and the Amiga 500 I used to do our orchestration was fairly limited - it came out sounding like chiptunes. By comparison, modern PCs using samples have always sounded to me like they were trying too hard. They just didn't sound right.

When I realised that you could emulate old machines on a PC and learn what was going on inside them, I went back to the older sounds. I've designed instruments for pop stars. I reprogrammed Game Boys for UK artist Damon Albarn, for example, turning them into real musical instruments.

I grew out of the home computers and started to use scientific machines. With Obsolete? I've gone right back to the beginning of what computers can do in terms of sound. It's not just about sound chips, but the electromechanical sounds they make: the fans, the tape readers, the teleprinters - crunchy sounds.

What kind of music is it?

I usually do my own weird version of pop music in one-off songs, but this is a lot more elaborate. It's a concert work - a complete study of Bletchley Park, its history and its people, and of mathematics and code-breaking.

There are hidden codes and themes of encryption within the music. For example, I created a rhythm on the Colossus [the world's first programmable electronic computer]. The Colossus was used to break wartime codes: the Nazis enciphered Morse code messages by adding a second layer of Morse on top. I think of Morse codes as rhythms, so the piece has multiple rhythms overlaid.

There is also one piece of music where I'm going to put the date of the concert into a hand-wound adding machine and turn the handle. As it turns it will make a rhythm for that particular night. But it's not going to come out as some sort of strict mathematical, avant-garde modern music. It does have all these things in it, but it's still music.

How do you turn primitive computer sounds into music?

I make chiptune music and I do circuit-bending, too. Chiptunes are about reprogramming old computers and using their sound chips to make new music. I've had to learn all the relevant computer languages from the 1970s to 1994. In fact, the best chiptune musicians are programmers.

Circuit-bending is taking an electronic device and short-circuiting it to create completely different outcomes to whatever it would originally have done.

I think the people at Bletchley Park were expecting me to just make pop music using the sounds of the machines, but that would trivialise it. The museum curators initially took a little persuading because some of the machines are worth, say, £4 million, and I have blown up machines in the past. But I promised to be sensible with them. I'm using samples in the performances, because there's no way I could use all the machines - they wouldn't let me move them. But some of them will be live.

Who are your musical inspirations?

I don't actually listen to chiptune music. My inspiration is really people like Marvin Gaye. For this piece, though, I've gone to 20th-century composers such as Schönberg, Bartok and Cage, to see how they explore themes.

What's next?

There are a few individual machines I'd like to work with. One is the Whirlwind from 1951, arguably the first computer to produce sound. I'd also like to do more projects like Obsolete?, but in different areas, such as using machines that have a specific function - in astronomy, say. I got everybody scared when I said I'd like to work on strategic nuclear defence machines.

I got everybody scared when I said I'd like to work on strategic nuclear defence machines

Listen to Chocolate Milk, from the album The Boy With The Digital Heart (2007, Hidden Youth Records UK)

Listen to Math, part of Pixelh8's new show Obsolete? (2009, Hidden Youth Records UK)

--
src:newscientist.com

Wife murdered for changing Facebook status

aakar@aakarpost.com — Sun, 25 Jan 2009 01:05:00 +0000

Edward Richardson, 41, was convicted of killing 26-year-old Sarah Richardson in a "frenzied and brutal attack" at her parents' home in Biddulph, Staffordshire, on May 12 last year.

Richardson, of Mayfield Road, Biddulph, was given a minimum term of 18 years in jail by a judge at Stafford Crown Court after a jury found him guilty of murder.

Fiona Cortese, from the Crown Prosecution Service, Staffordshire, said Richardson went to his in-laws' home, where his wife had been living since their separation in April 2008, after she failed to reply to his text messages following her change in status on social networking website Facebook.

She said: "Richardson became enraged when Sarah changed her marital status on Facebook to single and decided to go and see her as she was not responding to his messages.

"He gained entry by breaking the front door window and made his way into the property.

"Once inside he found Sarah in her bedroom and subjected her to a frenzied and brutal attack with a knife and then attempted to take his own life."

Mrs Richardson's parents, Beryl and Alan Boote, said their daughter's death had "devastated" the family.

In a statement released by police following Thursday's verdict, they said: "There simply aren't the words to describe how Sarah's death, and the awful way in which she died, has affected us. We all miss her so much.

"We're devastated and our lives will never be the way they were.

"It is important that we get justice for the taking of Sarah's life and we hope that Richardson will be an old man before he's ever allowed out of prison.

"Sarah was the loveliest daughter anyone could wish for. She was honest, loyal and sweet and everyone loved her.

"She loved all of her family to bits and to us she will always be precious and special."

Detective Inspector Andy Wall, from Staffordshire Police's Major Investigations Department, said: "She had decided that her marriage to Edward Richardson was over but this was clearly something he could not accept.

"The consequence was that Sarah lost her life in a brutal attack at her husband's hands in her family home.

"The verdict cannot bring Sarah back but we hope that it gives her family some form of comfort."

-----------------

telegraph.co.uk

Internet dream becomes a reality

aakar@aakarpost.com — Fri, 07 Nov 2008 11:32:00 +0000

A Nepali teacher has finally turned his dream into reality by connecting his remote mountain community to the internet.

In 2001 Mahabir Pun wrote to the BBC World Service's technology programme, then known as 'Go Dig'. He wanted to connect his village to the internet after the local high school received four used computers as a gift from students in Australia.

However, the lack of a phone line in the village made an internet connection almost impossible.

Wireless technology has connected 42 remote villages in Nepal

The only viable option was a satellite connection but the cost of this was beyond his means.

He went on to write an article for BBC News Online asking listeners for advice and received many responses from people all around the world offering their solutions.

Connecting classroooms

Several people also came forward to offer their help voluntarily and suggested wireless networking.

The idea was successfully tested between two villages in Nepal and as a result, Mr Pun was able to turn his vision of a networked Nepal into reality.

"At that time I got many emails from people around the world who told us about this technology that existed in the market," said Mr Pun.

We had to actually smuggle all the wireless equipment from America and Europe and build the network illegally

Mahabir Pun

"There were also some other people who were not interested in the technology but who were interested in helping to build classrooms in the school.

"They also helped to find equipment and grants from universities to build the network," he added.

Seven years on, he has now wired up 42 villages with a total population of about 60,000 people.

"The technology hasn't changed the day-to-day life of people because they have to work in their field, raise cattle and grow food.

"However, it has made their lives much easier when it comes to communicating between villages, with relatives living in the city or working abroad," said Mr Pun.

The future is near

There is now a telemedicine project, Voice over IP (VoIP) phone calls, internet terminals and places where people can trade goods from live yaks to handicrafts.

"We are using the wireless network for health, providing telemedicine services to the remote villages," said Mr Pun.

"We have connected three villages for testing to a city hospital because there are no clinics in the area.

Some of the first computers used were donated by other countries

"So, whenever people get sick, they can at least talk to the doctors and they don't have to go all the way to the city," he added.

One of the main challenges for Mr Pun was being able to gather all the equipment and construct wireless networks during a period of political and civil unrest in his country.

"The conflict in Nepal led the government to ban the import and use of all wireless equipment," said Mr Pun.

Maoist rebels were intent on setting up a communist republic against the constitutional monarchy.

"The rebels were very suspicious about our network, so we had to actually smuggle all the wireless equipment from America and Europe and build the network illegally," he added.

When King Gyanendra's rule ended in April 2006 the rebels agreed to talks on how to end the civil war and a peace deal was agreed in November.

"We got back democracy and after that we told these stories to the Members of Parliament in Nepal and asked them to legalise our wireless networks," said Mr Pun.

The project is now in its fourth phase and another 19 villages are set to be connected by the end of this year.

------------------

BBC World Service

Obama promises new era of scientific innovation

aakar@aakarpost.com — Wed, 05 Nov 2008 14:58:00 +0000

American people chose Barack Obama as the country's 44th president, promising a sea change in US policy that could affect not just the US, but the whole world.

Here we take a look at what Obama has pledged over the lengthy presidential campaign, to see what his administration will mean for science and technology.

In September, Obama unveiled a comprehensive Science and Technology Policy (pdf).

In it he promised to lead a new era of scientific innovation in America and to restore integrity to US science policy. This would be achieved by doubling the federal investment in basic research and by addressing the "grand challenges" of the 21st century, he said. The rhetoric gained him the public endorsement of 61 Nobel laureates.

Obama lacks a science background, though, and over the past 50 years it has been Republican, rather than Democratic administrations, that have tended to spend more on science. Whether Obama and his team can buck this trend in the current dire financial situation remains to be seen.

Key adviser

Although he consulted a range of Nobel prize winners during his presidential campaign, it is also crucial that Obama chooses his presidential scientific adviser early in his term, Joanne Carney of the American Association for the Advancement of Science told New Scientist in September.

"Having the science adviser in place early is going to be critical," Carney said. "It means that an individual can play a role in placing other key scientists throughout the federal agencies."

The outgoing Bush administration took 10 months to appoint John Marburger as the presidential science adviser – a position that didn't exist until Russia sent Sputnik into space 50 years ago.

By the time Marburger took up his post the president had already made clear his position on stem cells and climate change, leaving his new adviser with few decisions to make.

To the heavens

We already have some idea of Obama's own position on the big scientific issues – at the beginning of September he answered 14 questions posed by a consortium of scientific organisations.

Obama promised to lift the current ban on federal funding for embryonic stem cell research and support recommendations on genetic engineering as proposed by the Recombinant DNA Advisory Committee.

Technology could benefit under the Obama administration too, with promises to re-establish the National Aeronautics and Space Council – scrapped in 1993 by George Bush senior. The move would "expand our reach into the heavens and improve life here on Earth," said Obama.

Obama's attitude to the problem of climate change appeals to many in the scientific community – he aims to reduce greenhouse gas emissions to 1990 levels by 2020, and expand research funding into energy resources that reduce greenhouse gas emissions.

Read our environmental analysis of what the Obama victory will mean for the fight against climate change.

Health of the nation

Obama's policy on healthcare will be among the most carefully scrutinised. The US spends twice as much per head on healthcare as many other developed nations, but has little extra benefit to show for it.

With a healthcare bill that currently stands at over $2 trillion per year and is rising rapidly, the Congressional Budget Office (CBO) estimates that the US's health spending will soar to 49% of GDP in 2082 – it currently stands at 16%.

Shannon Brownlee, a specialist in health policy with the New America Foundation, a non-partisan think tank in Washington DC, told New Scientist that the antidote to soaring costs is more research into the comparative effectiveness of medical interventions.

That, coupled with greater use of electronic medical records and information technology, could help reduce the likelihood of duplicated diagnostic tests and minimise errors in drug prescribing.

Obama has already pledged billions of dollars for such systems, and supports further biomedical research into disease and responses to bioterror attacks.

Playing catch-up?

For too long the US has "[reduced] support for science at a time when many other nations are increasing it," Obama said in September. "A situation that already threatens our leadership in many critical areas of science."

That comment prompted New Scientist to wonder whether Obama feared America was falling behind in the scientific rat-race.

Whether or not Obama's scientific motives are to improve the world we live in, or to play science and technology catch-up with the other leading nations, the new US president has certainly been making the right noises for those that value science and technology. Now we have to wait and see if he can deliver.

------------------

new scientist

Programming Languages you must learn

aakar@aakarpost.com — Sun, 28 Sep 2008 14:39:00 +0000

These are list of some essentially learnable programming languages.

C is a standardized, general-purpose programming language. It is one of the most pervasive languages and the basis for several others (such as C++). Learning C is crucial. Once you learn C, making the jump to Java or C# is fairly easy, because a lot of the syntax is common. Also, a lot of C syntax is used in scripting languages. If you are a programmer, it's your base for programming as a programmer.

PHP is an open-source server-side, cross-platform, HTML scripting language, especially well-suited for Web development as it can be embedded into HTML pages. It is used for adding a life to HTML code. Main features are: Database Access, File Access, Application Control, Graphics and Extensible.

JavaScript

JavaScript must not to be confused with Java, JavaScript is a an object-oriented, scripting programming language that runs in the Web browser on the client side. It is smaller than Java, with a simplified set of commands, easier to code and doesnt have to be compiled. You can embedded it HTML, it is used in millions of Web pages to validate forms, create cookies, detect browsers and improve the design. With its simplicity to learn as well as wide use, its considered a great benifit to future carrier if you master in this.

Java

Java is an object-oriented programming language developed by James Gosling and colleagues at Sun Microsystems in the early 1990s. It is said as "beautiful language" by its programmers and is an alternative to .Net programming of microsoft.

Python

Python is an interpreted, dynamically object-oriented, open-source programming language that utilizes automatic memory management. It is designed to be a highly readable, minimalist language, many say it has a highest level language. Python is used extensively by Google as well as in academia because of its syntactic simplicity.

C# is a general-purpose, compiled, object-oriented programming language developed by Microsoft as part of its .NET initiative, it has evolved from C and C++. It is an essential part of the .Net framework.

AJAX (Asynchronous JavaScript and XML)

Technically AJAX is not a programming language, AJAX uses XHTML or HTML, JavaScript and XML to create interactive Web applications. After Google Maps put AJAX, well, on the map, the requests for AJAX professionals touched the sky. It is very hard to learn. Microsoft is developing a tool called Atlas that makes an average user to be a good user of AJAX.

Perl

Perl is an open-source, cross-platform, server-side interpretive programming language used extensively to process text through CGI programs. Perls power in processing of piles of text has made it very popular and widely used to write Web server programs for a range of tasks. It is essential to learn PHP or perl if you want to develop web Apps.

Ruby and Ruby on Rails

Ruby is a dynamic, object-oriented, open-source programming language. Ruby on Rails is an open-source Web application framework written in Ruby that closely follows the MVC (Model-View-Controller) architecture. It focuses on simplicity, productivity and letting the computers do the work, in a few years, its usage has spread quickly. As a bonus, many find it easy to learn.

VB.Net (Visual Basic .Net)

VB.Net is an object-oriented language implemented on Microsofts .Net framework. VB.Net is believed currently to be very popular and can also be "must-learns. It is currently dominating in workplaces where fast results are required.

Let all people in the world cheer.

- Pranav Nandan

Software Freedom Day 2008

aakar@aakarpost.com — Fri, 19 Sep 2008 10:17:00 +0000

Subject: Invitation : Software Freedom Rally, Candlelight Vigil and Software Freedom Day.

Dear all,
On the 19th of September, we are organizing Software Freedom awareness rally from Tinkune to Maaitighar from 4:30 PM. The rally will pass through the pavement without obstructing vehicular traffic. A candlelight vigil will be organized at Maaitighar Mandala from 6 PM onwards.

On the 20th of September, the main events of Software Freedom Day will start at 10:00 AM at Yala Maya Kendra, Patan Dhoka, Lalitpur.

There will be something for everyone of us. Please be there, irrespective of your profession to express your solidarity to us. Software Freedom is something everybody of us should advocate for.

Thank You,
Free/Open Source Software Nepal Community.
----------------------

www.aakarpost.com

Free software

aakar@aakarpost.com — Sun, 07 Sep 2008 12:53:00 +0000

The only divine thing that has touched the world in recent decades is "Free software". Imagine a world in which . . . .

-You have complete freedom to choose your path.
-We have boundless opportunities to seek for knowledge and learn from it.
-People are helped and help the other in the same way.
-People work together towards a single goal to improve a world .Hand in hand, bit by bit when millions of people contribute their ideas, there is birth of omnipotence power for helping humanity.

The thought of free software is all alike these fundamental freedoms.

Free software are not priceless software, they [can] be sold but along with your 4 freedoms restored. In this process the Free Software Foundation (FSF) is also benefited to some extent. We must remember after all FSF is the basis for freedom development in software. Other good thing is that in free software, users don't have to pay the distribution fee in order to use the software.They can copy the program from a friend who has a copy, or with the help of a friend who has network access. Or several users can join together, split the price of one copy, then each in turn can install the software. Also CD-ROM price is not a major obstacle when the software is free.

With free software, you can grow your knowledge. You know everything that is going inside your program. You can have complete options as per your need.You have access to source . You can choose things , you can add something you want or something other people want.

Distribute your version freely as long as you comply with rules of other people's freedom of software. Copyleft is a license that ensures every person's freedom of software.

Never in the world had we worked like this. Never in the world was knowledge free. We are right, we are strong, we represent the whole world. Thanks to people of earth igniting Free Software since 1985!
Let all people in the world cheer.

- Pranav Nandan

Fixing 0xc0000005 error in Google Chrome

aakar@aakarpost.com — Fri, 05 Sep 2008 11:23:00 +0000

We have been waiting for Google Chrome from a long time. And finally we get Google Chrome as well. But after installing it, some users are getting error. And they are unable to run it properly because of 0xc0000005 error.

It says:"The application failed to initialize properly (0xc0000005).Click on OK to terminate the application." And we must have to click ok and we are unable to use google chrome. May we are confused which type of browser is it. May it is not running properly because of some problem which is in your computer.

Well, Now I'm here to fix that problem. And this type of error has been seen in those computer which has symantec antivirus as an antivirus. But don't worry it is not a problem. And in some other cases may be .dll files are missing. So, if you are not using symantec as an antivirus but still seen such error and unable to run google chrome. Then, please check for .dll files.

Now let's fix the error which has been caused by symantec antivirus.Just follow the simple step:

* Back up the registry on an affected system
* Open the registry on the Agent system by entering regedit from a run prompt
* Navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SysPlant
* Open the Start DWORD
* Change the value to 4 to disable the drivers
* Reboot the system to commit the changes

--------
Now you have done, and you can run Google Chrome smoothly without any difficulty.

--
www.aakarpost.com

Google Chrome Browser is Out Now

aakar@aakarpost.com — Wed, 03 Sep 2008 02:46:00 +0000

Search and advertising giant Google will today launch a trial version of its own web browser in a clear attempt to break Microsoft's dominance over the way people access the web.

Google say their software, called Chrome, is designed to handle the latest web services such as video-rich pages and online office document editing faster and more securely.

A rethink of the browser is needed, says the firm, because existing programs have their roots in an age when the web offered only text and images.

Google confirmed its browser's existence in a company blog post after it mistakenly mailed details of Chrome to a blog.

Comic error

A 38-page comic book sent to the blog – available to view online here – described Chrome and its creators' hopes for the product.

A trial version of Chrome for Windows users will be available from this site on tomorrow. Versions for Apple Mac and Linux users are planned.

Chrome's launch coincides with the introduction last month of Internet Explorer 8 by arch-rival Microsoft last month.

Roughly 75% of all web users access the web using a Microsoft browser, around 18% using the open source Mozilla Firefox and 6% Apple's Safari browsers.

Open source

Google's engineers have used open-source code from a variety of projects including Apple's Web Kit used in Safari, and Firefox.

Chrome's code will itself be open source – available for other developers to enhance and expand.

Google says that Chrome will load pages faster and more securely than rival browsers. It also has a purpose-built engine for loading the interactive JavaScript code behind many of the advanced features of current websites. This is designed to Chrome run the next generation of yet-to-be-invented web applications.

Google stands to benefit from people using the new software. Google's Toolbar already collects information about the pages visited by users, which helps the company tune its search and advertising services. Chrome could collect information in a similar way.

'Porn mode'

Another feature is a privacy mode that lets users create an "incognito" window where "nothing that occurs in that window is ever logged on your computer".

A similar feature, dubbed "porn mode" by bloggers, was recently announced by Microsoft for Internet Explorer 8. Apple's Safari already features a private browsing mode.

John Lilly, chief executive of the non-profit company Mozilla Corp that promotes Firefox, said Google had recently renewed its arrangement to be the largest financial backer of his company until 2011.

Mozilla recently introduced its own upgraded browser, Firefox 3, and has collaborated with Google on technical issues in the past, such as how to make browsers more secure.

Lilly says that Mozilla and Google would continue to collaborate where it made sense for both organisations.

But he acknowledges things have changed: "With [Explorer], Firefox, Safari, Opera, etc – there's been competition for a while now, and this increases that."

Download: Google chrome Browser
--
www.aakarpost.com

Embedded Comment Form in Blogger

aakar@aakarpost.com — Mon, 01 Sep 2008 17:33:00 +0000

Dear Blogger Friends,

Today I'm going to share a new innovation in blogger. Actually I'm surfing some friends blog and I've seen, comment form in the same page. I'm really happy and shocked both at a time, about this features. So, I've gone through Google, I've found the solution and I'm going to share over here.

Many of we users of Blogger are searching for such innovation from blogger group. Now we have. This is very easy to implement in your blog and is directly powered by blogger.Blogger have developed an inline (embedded) comment form which can be enabled through Blogger in Draft. This is probably the most requested feature for Blogger, and I'm sure many of you will want to use this straight away! Now we can place comment form in same page of blog as in wordpress blog.

Now get started with it:
May be you haven't use blogger in draft yet. So, as to enable this feature first of all go to Blogger In Draft because from Blogger you are unable to see three options in comments setting page.
So, first of all make sure that your are in Blogger Draft.

Then go to Settings>Comments and scroll down the page to see the new "Comment form placement" setting:

Check the radio setting for "Embedded below post" which will enable the display of the comment form below your blog posts.

If you have customized your template, you will need to make a small change to your template code for this comment form to display. But don't worry, it's a very simple customization to make!

Simply go to Layout>Edit HTML in your blog's dashboard and check the "Expand widget templates" box.

Then,Search for this line in your template code:(Press Ctrl+F for quick search.)

Immediately after this above line, add the following line of code:

Then save your template. This method adds the required code for the comment form without having to alter the whole comment area. Later you may return to blogger dashbord or you may use blogger draft dashboard.

At last, I'd like to thank bloggerbuster for this nice info.

--
www.aakarpost.com

Data Type and Data Structure

aakar@aakarpost.com — Sun, 31 Aug 2008 02:51:00 +0000

Data Type:

A method of interpreting a bit pattern is called a data type.
Binary integers, binary coded decimal non-negative integers, real numbers, character strings are data type.

Data Structure:
It is an arrangement of the different storage types in the computer which are associated with certain mathematical and logical concepts of data.
eg. array, structure, union, class, enumeration.

--

www.aakarpost.com

Mexicans get microchipped over kidnapping fears

aakar@aakarpost.com — Mon, 25 Aug 2008 14:34:00 +0000

Affluent Mexicans worried by soaring kidnapping rates are spending thousands of dollars to implant tiny transmitters under their skin so satellites can help find them even when stuffed in the boot of a car.

Kidnapping jumped almost 40% between 2004 and 2007 in Mexico, according to official statistics. Mexico ranks with conflict zones like Iraq and Colombia as one of the worst countries for abductions. The recent kidnapping and murder of Fernando Marti, 14, the son of a well-known businessman, sparked an outcry in a country already hardened to crime.

More people, including a growing number of middle-class Mexicans, are seeking to have a microchip implanted under their skin by Xega, a Mexican security firm whose sales jumped 13% this year. The company claims to have more than 2,000 clients.

Tagged and tracked

Detractors say that the chip is little more than a gimmick that serves no real security purpose. The company injects the crystal-encased chip, the size and shape of a grain of rice, into clients' bodies with a syringe.

A transmitter in the chip communicates with a larger GPS-enabled device carried by the client, Xega says. That gadget reports its location to the company when the owner presses a panic button, something the device could arguably do without an under-skin chip.

Katherine Albrecht, a US consumer privacy activist, says the chip is a flashy, overpriced gadget that only identifies a person and cannot locate someone without another, bigger GPS device that kidnappers can easily find and destroy.

She says fear of kidnapping was driving well-off Mexicans to buy an unproven technology. "They are a prime target because they've got money and they've got a worry and you can combine those two and offer them a false sense of security which is exactly what this is," she says.

Cristina, 28, who did not want to give her last name, was implanted along with seven other members of her family last year as a preventive measure. "It's not like we are wealthy people, but they'll kidnap you for a watchï¿½Everyone is living in fear," she says. The chips cost US$4,000 plus an annual fee of $2,200.

Most people get the chips injected into their arms between the skin and muscle where they cannot be seen.

Most kidnappings in Mexico go unreported, many of them cases of "express kidnapping" where the victim is grabbed and forced to withdraw money from automatic cash machines. Official statistics show 751 kidnappings in Mexico last year, but the independent crime research institute ICESI says the true number could have exceeded 7,000.

Booming business

Xega, based in the central Mexican city of Quererato, designed global positioning systems to track stolen vehicles until a company owner was kidnapped in broad daylight in 2001. The firm sees kidnapping as a growth industry in South America and plans to expand its services next year to Brazil, Colombia and Venezuela.

............newscientist.........

Ancient Greek 'computer' an astronomical tool

aakar@aakarpost.com — Thu, 31 Jul 2008 11:51:00 +0000

INSCRIPTIONS on a mysterious 2000-year-old clockwork device suggest that the artefact was inspired by earlier devices made by the great Greek mathematician Archimedes.

The so-called "Antikythera mechanism" has puzzled historians since it was salvaged from an ancient shipwreck near the Greek island of Antikythera in 1901. It dates back to about 100 BC, and consists of more than 30 bronze gear wheels and pointers, enclosed in a wooden case.

The device is by far the most advanced scientific instrument to survive from antiquity - nothing else close to its complexity shows up in archaeological records for more than 1200 years, when mechanical clocks appeared in medieval Europe.

The Antikythera mechanism is thought to be a mechanical computer, which used sophisticated algorithms to calculate the motions of celestial bodies. A dial on the front showed the position of the sun, moon and probably the planets in the zodiac, while the back displayed a 19-year lunisolar calendar, as well as the timing of eclipses (Nature, DOI: 10.1038/nature05357; Interdisciplinary Science Reviews, vol 32, p 27).

The mechanism may have been used by philosophers to show the workings of the heavens, as suggested by the Roman author Cicero, who wrote in the 1st century BC of bronze devices that erroneously modelled the movements of the sun, moon and planets around Earth.

The origin of the Antikythera mechanism was a mystery, but newly deciphered inscriptions show that its calendar used local month names. They match those used by Greek colonies founded by the city of Corinth, and a prime candidate is Syracuse, in Sicily (Nature, DOI: 10.1038/nature07130).

Alexander Jones of the Institute for the Study of the Ancient World in New York, who deciphered the inscriptions, says the presence of a local calendar supports the idea that rather than being used by astronomers, the mechanism was intended for demonstrations, albeit to a small, educated elite.

Jones and his colleagues say the identification of Syracuse is intriguing because one of the models Cicero mentioned in his writings was made by Archimedes in the 3rd century BC. Archimedes worked in Syracuse, so the Antikythera mechanism, made at least a century later, might be part of a tradition of geared mechanisms begun by the legendary mathematician.

But this also prompts a new mystery, because the wreck on which the mechanism was found was a Roman ship, sailing not from Sicily but from the eastern Mediterranean in 70-60 BC, mostly likely taking looted Greek treasures back to Rome.

"The route of the ship is puzzling," says Paul Cartledge, a professor of Greek history at the University of Cambridge, UK. "It was going from east to west, and Antikythera is well to the east of Syracuse."

Cartledge says it's not impossible that the instrument was designed in the east – Rhodes or Alexandria say – for use in Syracuse.

However the mechanism seems to have been several decades old when it was taken on its final journey. So perhaps it was made in Syracuse for a wealthy owner who subsequently moved to the eastern Mediterranean, or was carried there as a gift or votive offering, before later becoming part of booty taken for Rome.

--
newsceintist

UK releases classified UFO files

aakar@aakarpost.com — Wed, 14 May 2008 14:07:00 +0000

The UK is making decades' worth of classified files relating to UFOs freely available to the public.

On Monday, the British Ministry of Defence (MOD) began a four-year-long project to transfer the files to the UK's National Archives, which will post them for public perusal. The announcement comes about one year after France made its UFO files available online.

The project is a response to massive public interest and numerous Freedom of Information (FOI) requests about UFOs, or Unidentified Flying Objects, that have been filed over the years. Nick Pope, a former UFO investigator at the MOD, called the release "a great day for open government and freedom of information".

When complete, the National Archive will contain some 160 UFO-related MOD files from the 1950s to 2007, representing the single largest release of records in the ministry's history.

Rejected abductee

Eight files are currently available on a dedicated UFO page at the National Archives website. The files are from 1978 to 1987 and include reports of UFO sightings and alien encounters from civilians as well as military personnel.

The reports range from mysterious to downright bizarre. One elderly man said he was given a personal tour of an alien spacecraft by beings wearing green overalls and then was ultimately rejected for abduction because of his age.

Also included is a behind-the-scenes look at the MOD's preparation for a 1978 debate about UFOs in the British House of Lords. Lord Strabolgi (David Kenworthy) gave the official government response in the debate, which was initiated by Lord Clancarty (Brinsley le Poer Trench), a ufologist.

"There really are many strange phenomena in the sky, and these are invariably reported by rational people," Lord Strabolgi said in his closing remarks. "But there is a wide range of natural explanations to account for such phenomena. There is nothing to suggest to Her Majesty's Government that such phenomena are alien spacecraft."

Pragmatic approach

David Clarke, an expert in UFO history at Sheffield Hallam University in the UK, said the Ministry of Defence took the debate, and its subject, seriously. "The papers show they went to a considerable amount of work to actually produce background briefings for Lord Strabolgi," Clarke said in a National Archives podcast.

The files also reveal the ministry's pragmatic approach to UFO reports. From the perspective of the British government, UFOs are worth investigating only because they might pose a threat to national security.

"As soon as they were able to say this particular UFO isn't an enemy aircraft, they weren't interested in pursuing it any further," Clarke said.

When complete, the National Archive will contain some 160 UFO-related MOD files from the 1950s to 2007, representing the single largest release of records in the ministry's history.

Rejected abductee

The UK is making decades' worth of classified files relating to UFOs freely available to the public.

When complete, the National Archive will contain some 160 UFO-related MOD files from the 1950s to 2007, representing the single largest release of records in the ministry's history.

Rejected abductee

Pragmatic approach

"As soon as they were able to say this particular UFO isn't an enemy aircraft, they weren't interested in pursuing it any further," Clarke said.

The MOD's release of its UFO files should go a long way towards debunking notions of a government cover-up, Clarke said. "It's a good move on behalf of the Ministry of Defence to put this material in the public domain and demonstrate what they know, which doesn't amount to much.""There really are many strange phenomena in the sky, and these are invariably reported by rational people," Lord Strabolgi said in his closing remarks. "But there is a wide range of natural explanations to account for such phenomena. There is nothing to suggest to Her Majesty's Government that such phenomena are alien spacecraft."

Pragmatic approach

"As soon as they were able to say this particular UFO isn't an enemy aircraft, they weren't interested in pursuing it any further," Clarke said.

src:http://space.newscientist.com/article/dn13894-uk-releases-classified-ufo-files.html?feedId=online-news_rss20

Emergency 2.0 is coming to a website

aakar@aakarpost.com — Sat, 03 May 2008 02:24:00 +0000

In September 1970, when wildfires displaced tens of thousands of people in Southern California, overwhelming emergency services, residents took matters into their own hands. They found a place for evacuees to gather and organised the washing of exhausted fire-fighters' clothes. Fast forward to October 2007, when wildfires ravaged the state again and residents banded together, this time in a way that wasn't possible in the seventies.

Armed with an array of online "social media" tools such as blogs, annotatable maps, photo sites and instant messenging services, they were able to gather and disseminate information on, for example, the progress of the fire, the location of evacuation areas and shelters, and which schools and businesses were closed - information unavailable through traditional channels.

http://technology.newscientist.com/channel/tech/mg19826545.900-emergency-20-is-coming-to-a-website-near-you.html?feedId=online-news_rss20

Lunar Chariot prepares to tear up some moon dust

aakar@aakarpost.com — Wed, 26 Mar 2008 02:26:00 +0000

This isn't your father's idea of a space rover. NASA's Chariot is the first prototype in a new line of lunar vehicles that could someday bulldoze roads, dig trenches, and drill for minerals on the moon. And it is already proving as nimble as it is powerful in earthbound testing.

Chariot, a two-tonne "truck" with a top speed of 20 kilometres per hour, has been tearing up the Lunar Yard, a test bed at the Johnson Space Center in Houston, Texas, since engineers there completed construction of the vehicle in September of 2007.

The Lunar Yard is a 2-acre expanse of small hills covered in a mix of sand and crushed granite designed to mimic the loose surface of the moon.

The current prototype has a detachable plough for turning over lunar soil, but future designs may incorporate a back hoe, or excavator, and a drill rig capable of boring into the lunar soil. "Building a lunar truck isn't so much 'rocket science' as it is applying what you know about earth-bound trucks," says Lucien Junkin, Chariot's lead engineer.

Mars lessons

Independent steering on each of its six pairs of wheels allows the vehicle to spin on the spot, zigzag up steep crater walls, and manoeuvre into tight spaces with ease.

The Chariot – so named because the current model has no seats, windows, or doors, and can be driven from the rear – can also lower its chassis to the ground making it easier for astronauts in bulky spacesuits to climb aboard.

The design builds on lessons learned from Spirit and Opportunity, NASA's twin rovers that have been exploring Mars for the past four years.

Both continue to limp across the Red Planet despite each having lost control of one their six wheels. Having six pairs of wheels, each powered independently, should allow Chariot to carry on functioning should anything go wrong with one of its wheels.

The current prototype uses fans to cool its battery-powered motors. This would not be possible on the moon, so finished versions will disperse heat by circulating fluid instead.

Improvements planned

Initial tests of the vehicle's speed, turning capacity, and ploughing ability at the Lunar Yard have exceeded its designers' expectations. Chariot's engineers are, however, trying to improve steering response times. They also hope to give the vehicle the ability to raise or lower each individual wheel to keep its chassis level on uneven ground.

The lunar truck, which was designed and built in 11 months at a cost of approximately $3.5 million, will undergo further testing this summer at Moses Lake State Park in Washington State, where the region's steep, shifting sand dunes offer similar topography to that of the moon.

Junkin says these tests, scheduled for the first two weeks of June will be open to the public. "America paid for it, they ought to be able to get a chance to see it at work," he says.

........'http://technology.newscientist.com/channel/tech/dn13529-lunar-chariot-prepares-to-tear-up-some-moon-dust.html?feedId=online-news_rss20'.........

The Computer User's Reboot

aakar@aakarpost.com — Fri, 14 Mar 2008 17:43:00 +0000

Don't you wish when life is bad
and things just don't compute,
That all we really had to do
was stop and hit reboot?

Things would all turn out ok,
life could be so sweet
If we had those special keys
Ctrl, Alt, and Delete

Your boss is mad, your bills not paid,
your wife, well she's just mute
Just stop and hit those wonderful keys
that make it all reboot

You'd like to have another job
but you fear living in the street?
You solve it all and start a new,
Ctrl, Alt, and Delete.

Oral sex-related cancer at 30-year high

aakar@aakarpost.com — Fri, 29 Feb 2008 18:15:00 +0000

The incidence of oral cancer due to a virus transmitted during oral sex has increased steeply over the last 30 years, according to research in the US. And scientists relate this trend to changes in people's sexual behaviour.

The number of tongue, mouth and throat cancers due to the sexually transmitted human papilloma virus (HPV), which can also cause cervical cancer in women, rose by about a third from 1973 to 2004, say researchers.

The team led by Maura Gillison at Johns Hopkins University in Baltimore, Maryland, US, studied trends in oral cancers recorded by US National Cancer Institute registries.

Earlier work by this team and others had established a link between certain strains of the common sexually transmitted virus and oral cancer. The latest study, which looked at nearly 46,000 cases, is the first to quantify an increase in mouth and throat cancers due to sexual activity.

'Vaccinate boys'

"What we do know is that the prevalence of HPV is high, particularly among young people and this shouldn't be a surprise given that, since the sexual revolution, people have been having more sexual partners," says Lesley Walker, director of cancer information at Cancer Research UK.

The rise was largest among young white males, suggesting this group is more likely to have oral sex at a younger age now than it was 20 years ago, says Gillison's team. It adds that further research on the role of race and sex, and oral sexual behaviour, is needed.

What is not in doubt, says Gillison, is the need to consider giving boys the HPV vaccine, to protect them from the disease.

A Merck vaccine is currently licensed for use in young women and girls to protect them against the most common cervical cancer-causing strains of HPV. These strains are also thought to cause oral cancer, as well as penile and anal cancer.

"We need to start having a discussion about those cancers other than cervical cancer that may be affected in a positive way by the vaccine," urges Gillison.

Cost concerns

One US campaign group, the Oral Cancer Foundation, is now calling on the US Food and Drug Administration to "move rapidly to approve the vaccination of young boys with the cervical cancer vaccine, to reduce the pool of HPV16 [a particularly aggressive strain]" and protect them from oral cancer.

Walker says however, given the high cost of such a programme, authorities might require more evidence that such a move really would prevent a significant number of male cancers.

Tonsil and throat cancers affect about two in every 100,000 adults in the US and about half a million people around the world each year.

Although, oral cancers linked to HPV infection have risen, the study notes the incidence of oral cancers in parts of the mouth or throat not linked to HPV infection remained constant until 1982, and then started to decline.

Gillison says this is probably due to falling consumption of tobacco and alcohol, which are also linked to the cancers.

http://www.newscientist.com/article/dn13389-oral-sexrelated-cancer-at-30year-high.html