Education: Yenka Light and Sound modeling software

I've been using Falstad's freeware Java applets for teaching acoustics and oscillation concepts in the classroom for years now. I recently decided to give Crocodile Clips' Yenka Light and Sound modeling software a try after some of my own children enjoyed using it in school. At first it was to take advantage of the free license for home use (yes, FREE). Now, however, I'm going to use it in classes thanks to the numerous models already built-in and even more content online. My favorite built-in model so far is "Speed of Sound" - which lets you add other media, such as vacuum, water, and wood, and see how the speed of sound changes and then interacts with the sound wave in air, assuming it exits the extra media at all - very cool!

Not to leave optics out, there are informative models for angles of reflection, refraction, mirrors, lenses, telescopes, and more. For instance, to show that the angle of incidence equals the angle of reflection, the student drags two protractors into the workspace and measures both angles as the (virtual) beam of light bounces off the mirror. Simple, but effective. Many more sophisticated models are available too, plus you can build your own and save them for later use (as an educator, I like that).

Yenka also covers more than the physics of sound and light - mathematics, chemistry, computers, electronics, and other packages are also available. I've tried the chemistry package with my boys. Being boys, they were particularly pleased with being able to experiment with (virtual) dangerous substances after having to suffer through the kid-safe chemistry sets sold in stores these days.

Crocodile Clips is based in the UK, so American and other visitors to their website may not understand the references to terminology used in the British education system. Luckily, the laws of physics do not change as a result of the software leaving the UK! Yenka is a free download for students to use at home. Use outside of the home requires buying a license, of course. Finally, it works on Mac and Windows operating systems.

Enjoy!

Image Forensics: Adobe launches CS4

Adobe has launched the latest version of its Creative Suite, which includes, most importantly for image/video forensic types, Photoshop. Headline features of Photoshop CS4 include:

• GPU-based drawing of documents onscreen (for speed improvements)
  
• 64-bit for Windows (but not for Mac OS-X, at least yet)
  
• Expanded 3-D paint, lighting and rendering tools

Hat tip: Ars Technica

Image Forensics: More on tamper detection

Steve Eddins (Mathworks Inc., USA), writing on his company-sponsored blog on image processing, has an excellent post regarding an article by Professor Henry Farid in the June 2008 edition of Scientific American (USA, center-left, scientific magazine). The article is primarily about tamper detection or, in other words, spotting retouching or "photoshopping" of photographs.

Image Forensics: How to spot photo retouching

Slate (US, center-left online magazine) has an article (Were the Dove ads retouched? How to spot Photoshop chicanery) on some of the techniques used in identifying if a image has been retouched. In a forensic examination of evidence, this procedure is known as tamper detection. It should be noted that the author, Jacob Leibenluft, reached out to several experts while researching the topic, including George Reis of Imaging Forensics.

Enjoy!

Speech Recognition: Application to university lectures

Technology Review (an MIT publication) has a comprehensive article on an up-to-date application of speech recognition, including both the recognition engine and the user interface layers - namely, MIT's Lecture Browser website, a search application for video lectures.  The article is very well written and is approachable by anyone with a bit of science background.

Computer: MacBook update

In case you are interested in the experiences of a recent convert to the "Cult of Apple", my impressions of the Apple MacBook are still very positive. At this point, I have had far fewer issues with this laptop than with any previous laptop that was 'designed and built for Windows'.  I phrased it that way because, as you might recall, I am running Mac OS-X and Windows XP Pro on this machine.  I've had no significant problems with either one.

As far as tested software packages, I've extended the list of applications I've installed and tested on the Mac OS to include Matlab (a signal processing software environment useful for filtering and plotting data, including audio and video), Octave (a freeware alternative to Matlab), Remote Desktop (for connecting to a networked Windows desktop in the office), QuickSilver (a desktop search application to beat all desktop search applications), and Gimpshop (a freeware alternative to Adobe Photoshop).  I haven't fully tested all of them, but I can say that they all install and run correctly.  Octave did give a bit of trouble during installation, but once I got it to launch the first time, it seems to be behaving properly now.

Admin: MacBook replaces lemon Windows notebook

I won't bore everyone with details about the last rites on my old notebook, but suffice it to say that the manufacturer agreed to fully refund the purchase price of the notebook and I am back to blogging again.

What may not be so boring is that I replaced that Windows notebook with a MacBook.  The MacBook has a dual core Intel processor and is running both Apple's OS-X and Microsoft's Windows XP Pro.  The Windows operating system is running in virtualization mode using a program called Parallels (note: I had to purchase a copy of Windows and Parallels separately, but they were fairly inexpensive).

As far as audio and video processing goes, I have been able to load and run Acoustica, Audacity, Audition, Clarifying Technologies, and Signalscape on the MacBook and all have worked in real-time for the types of files I tested with.  Due to work commitments, I have not been able to take enough time to "make friends" with the native Mac sound and video applications, but hope to do that slowly over the next few months. I'll report back my on observations.  If anyone has a preference as to a specific application for audio or video forensics they would like me to give priority to, just let me know in the comments or off-line.

In the meantime, Brian Dipert (Senior Technical Editor over at EDN) has also been transitioning over to a MacBook and has blogged about his experiences in several posts, this one being the latest as of this writing.