With data mining it is possible to let the data itself determine the groups. This is one of the black-box type of algorithms that are hard to understand. But in a simple example – again with purchasing behavior – we can imagine that the purchasing habits of different hobbyists would look quite different from each other: gardeners, fishermen and model airplane enthusiasts would all be quite distinct. Machine learning algorithms can detect all of the different subgroups within a dataset that differ significantly from each other.
Category Archives: Technical
Open Source SQL Database Security, SQL Injection Prevention
GreenSQL is a Database Security solution.
GreenSQL is an Open Source database firewall used to protect databases from SQL injection attacks. GreenSQL works as a proxy and has built in support for MySQL and PostgreSQL. The logic is based on evaluation of SQL commands using a risk scoring matrix as well as blocking known db administrative commands (DROP, CREATE, etc). Commercial version of GreenSQL supporting Microsoft SQL Server, MySQL and PostgreSQL, The GreenSQL Express version is available for FREE at GreenSQL.com database security solutions.
via | Open Source SQL Database Security, SQL Injection Prevention.
unix – Insert the carriage return character in vim
Type: ctrl-v ctrl-m
On Windows Use: ctrl-q ctrl-m
Ctrl-V tells vi that the next character typed should be inserted literally and ctrl-m is the keystroke for a carriage return
via unix – Insert the carriage return character in vim – Stack Overflow.
Software defined radio from a USB TV capture card
So far, two USB sticks have been tested and the unit with the largest frequency range (64 – 1700 MHz) is available direct from China for $20.
via Software defined radio from a USB TV capture card – Hack a Day.
These cards demodulate the frequency and send all the data to the computer and is decoded via software. If you have one of these capture cards lying around, you can grab the software and load it up on your *nix box. Right now, the software only writes directly to a file, and may drop a few samples if writing to a hard disk instead of ram. Small problems, but we’re sure this project will pick up steam in the very near future.
Hackers Can Steal Credit Card Information From Your Old Xbox, Experts Tell Us
So what should you do if you want to get rid of your Xbox 360 but you don’t want your personal information compromised? Podhradsky recommends detaching your 360’s hard drive, hooking it up to your computer, and using a sanitization program like Darik’s Boot & Nuke to wipe everything out. Just reformatting the system isn’t enough.
via Hackers Can Steal Credit Card Information From Your Old Xbox, Experts Tell Us.
Chapter 4 The amazing em unit and other best practices
The foremost tool for writing scalable style sheets is the “em” unit, and it therefore goes on top of the list of guidelines that we will compile throughout this chapter: use ems to make scalable style sheets. Named after the letter “M”, the em unit has a long-standing tradition in typography where it has been used to measure horizontal widths. For example, the long dash often found in American texts (–) is known as “em-dash” since it historically has had the same width as the letter “M”. Its narrower cousin (-), often found in European texts is similarly referred to as “en-dash”.
The meaning of “em” has changed over the years. Not all fonts have the letter “M” in them (for example Chinese), but all fonts have a height. The term has therefore come to mean the height of the font – not the width of the letter “M”.
In CSS, the em unit is a general unit for measuring lenghts, for example page margins and padding around elements. You can use it both horizontally and vertically, and this shocks traditional typographers who always have used em exclusively for horizontal measurements. By extending the em unit to also work vertically, it has become a very powerful unit – so powerful that you seldom have to use other length units.
IETF attendees reengineer their hotel’s Wi-Fi network
What happens when a bunch of IETF super nerds show up in Paris for a major conference and discover their hotel’s Wi-Fi network has imploded?
They give it an Extreme Wi-Fi Makeover.
HTML link tag
Definition and Usage
The <link> tag defines the relationship between a document and an external resource.
The <link> tag is most used to link to style sheets.
Tips and Notes
Note: The <link> element must be embedded in the head section, but it can appear any number of times.
Differences Between HTML and XHTML
In HTML the <link> tag has no end tag.
In XHTML the <link> tag must be properly closed.
via HTML link tag.
HTML span tag
The <span> tag is used to group inline-elements in a document.
The <span> tag provides no visual change by itself.
The <span> tag provides a way to add a hook to a part of a text or a part of a document.
When the text is hooked in a <span> element you can add styles to the content, or manipulate the content with for example JavaScript.
via HTML span tag.
From The SPAN Tag
Use span tags when you don’t want any changes to the layout other than exactly what you specify in the styles of the span. For example, if you use a <div> or <p> most browsers will add space around the element, because they are block elements.
System Development Life Cycle
Computerworld – Once upon a time, software development consisted of a programmer writing code to solve a problem or automate a procedure. Nowadays, systems are so big and complex that teams of architects, analysts, programmers, testers and users must work together to create the millions of lines of custom-written code that drive our enterprises.
To manage this, a number of system development life cycle (SDLC) models have been created: waterfall, fountain, spiral, build and fix, rapid prototyping, incremental, and synchronize and stabilize.