User: MikeyO

How big is your neighborhood?

On: Cheap Long Distance Wireless Networking

They were able to communicate 14 km with two 17db gain yagi antennas. If you wanted to cover a neighboorhood, the base antenna would have to be an omni-directional antenna. The omni-directional antenna from lucent is a 9 db gain antenna. A 8 db difference is about 1/6 the radiated power (db = 10 log10(p1/p2)). So you should be able to cover about a 2km radius (provided that your laptop is still using the yagi) I think.

Can a photon have mass

On: Practical Gravity Shielding for Spacecraft?

There seems to be a lot of people arguing whether or not a photon can have mass. It seems that a lot of these arguments are just differences in semantics.
Here is a good link from the Relativity FAQ which may clear up some of these issues.

Re:I hate Java

On: C++ Answers From Bjarne Stroustrup

For instance a fragment of a C++ program that reads in a file and gets a list of the starting positions for every word in the file:

map > word_positions;
string word;
while (cin)
{
cin >> word;
word_positions[word].push_back((int)cin.tellg() - word.size());
}

Writing the equivalent in Java would take 20+ lines

Heres a java object to do this.

import java.io.*;
import java.util.*;
public class TokenizeStdin extends
BufferedInputStream
{
TokenizeStdin( Hashtable wordMap ) throws IOException
{
super( System.in );
StreamTokenizer strTok = new StreamTokenizer( this );
while( strTok.nextToken() != StreamTokenizer.TT_EOF )
{
if( !wordMap.containsKey( strTok.sval ) )
wordMap.put( strTok.sval, new Vector() );
( ( Vector )wordMap.get( strTok.sval ) ).addElement( new Integer( pos - strTok.sval.length() ) );
}
}
}
This in not a snippet! This is the whole shebang. If the above C++ comment were expanded to make it compile ( the java version will compile as is ) it would be as long as my java version. I agree that the Java version is not as pretty, but that is mostly due to the fact that the java container classes have not reached the level of maturity that the Standard C++ containers have, yet. But remember that for the first 8 - 10 years of C++, templates were not available, and there were no Standard C++ containers. People are working on adding templates to java. See gjc. Once this has reached maturity, good templatized container classes can't be far behind.