Cape Lookout Hike

This hike was in my to-do-list for a long while, but I was not able to find the time to go and get it done. Finally, today I was able to see it. The best part was that my 1-year old Meryem and 4.5 half year old Omer were with us as well. This was Omer's second and Meryem's first hike. Omer walked all the way by himself and Meryem enjoyed being carried by her mom and dad. As for the trail status, occasionally it was muddy. Except for the very steep cliff on the end of the trail, it is very family friendly and easy paced.

I did geotagging using the Sony GPS-CV3KA and the accuracy was overall satisfactory. I also had my Samsung Google Nexus S geotag using the Google "My Tracks" app. But it was having trouble in getting the GPS satellite connection. So, dedicated GPS machines still seem to perform more accurately than the smartphones (at least from my experience). Below are snapshots of our track overlayed onto Google Earth and maps.

 

Omer GoPro'ing

Omer loves biking... and I am looking for ways to utilize the GoPro camera as much as possible. So, I decided to combine these two together. I didn't have the right gadget to mount the GoPro into Omer's bike so we did some manual work. After a couple of tries, I believe we got a nice shot.

CVS Gated Check-in problem (cvs update: conflict file has been added, but already exists)

I added new files to the branch  (not the trunk) of a CVS repository using the cvs commit. Then later, I ran a gated check-in to commit the changes into the CVS branch. The gated check-in ran successfully and then then committed the files. But because the newly added files were not in the repository previously, the cvs log of such a file showed the following:

machinename> cvs log $LOCALFOLDER/foo.cpp

RCS file: $CVSROOT/Attic/ foo.cpp,v

Working file: $LOCALFOLDER/ foo.cpp

head: 1.1

branch:

locks: strict

access list:

symbolic names:

        BranchName: 1.1.0.2

keyword substitution: kv

total revisions: 2;     selected revisions: 2

description:

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

revision 1.1

date: 2012/08/27 14:22:57;  author: joe;  state: dead;

branches:  1.1.2;

file foo.cpp was initially added on branch BranchName.

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

revision 1.1.2.1

date: 2012/08/27 14:22:57;  author: joe;  state: Exp;  lines: +36 -0

[Gated Checkin]

Original message

=============================================================================

Later, I modified the same files and wanted to run another gated check-in, but the following error was given and the check-in failed:

cvs update: conflict: foo.cpp has been added, but already exists

C foo.cpp

This is because the gated check-in commits from the not local folder but the Qualify folder and as a result it sees the same file again and gives this error. To overcome this problem, the best way is to run cvs update on the local folder. If it does not work, move the files in the local directory and then run the cvs update again to check out the already existing files from the repository. Once this is done, the previously moved files can be moved back and overwrite the existing ones. This should solve the problem. 

Optical Ring Resonator (FDTD Animation)

Here, we demonstrate the propagation phenomena in a double optical ring resonator structure. A windowed cosine excitation is pumped in the bottom dielectric straight waveguide and as this input mode propagates past the circular waveguides, the optical coupling occurs yielding wave propagation in the circular waveguide. The structure is chosen for illustration purposes only and it is possible to see several coupling between the circular and straight waveguides. In practice, various combinations are used to obtain optical filtering. For more information, you can check the wikipedia page


Also see below:
Oblique Plane Wave Reflection From Half Space
Radiation from a Circularly Tapered Dielectric Waveguide
Right Hand Circular Polarization (RHCP) Animation
Linear Polarization Animation
Left Hand Elliptical Polarization (LHEP) Animation
Standing Wave Pattern (SWR) Animation
Electromagnetic Propagation of UWB Short Pulse in Random Medium 
Half Wavelength Dipole Antenna Radiation 
Dipole Antenna Radiation 
Dish Antenna Animation (Parabolic reflector) 
FDTD Simulation of a Half Convex Lens
Diffraction from a Single Slit (FDTD Animation)
Ground Penetrating Radar (GPR) B-Scan Collection (FDTD Animation )
Ground Penetrating Radar (GPR) FDTD Animation

Ground Penetrating Radar (GPR) B-Scan Collection (FDTD Animation )

Here, B-scan data collection of a simple ground penetrating radar (GPR) is animated through the use of Finite-difference time-domain (FDTD) method. The upper part of the animation shows the 2D spatial propagation of the short pulse transmitted from the antenna at different spatial locations. The transmitting antenna shoots a short electromagnetic pulse (with a central frequency of 600 MHz) into the subsurface where the relative dielectric permittivity is 4. The short pulse is reflected from the air-soil interface and then from the target embedded in the subsurface. Then, the scattered signals are recorded by the same antenna in the receiving mode. The lower part of the animation corresponds to the received signals (A-scan) at the same antenna for each of the positions. This constitutes the so-called B-scan data collection.

Running Doxygen (simple example)

First, we have to generate a configuration file for detailed specifications. This can easily be done by doxygen itself by simply typing:

doxygen –g

This will dump a default Doxyfile which is ready for further editing. We can edit the Doxyfile for flags (e.g. include subfolders etc). Once editing is finished, we can run

doxygen Doxyfile

This will generate the html or latex folder containing the documentation. In the Latex folder, you can type make to generate the desired pdf file.

How to add CVS ID Tag (CVS Keywords in source file)

To have the CVS ID tags in your source code, you can basically add the following line to your file:

// $Id$

Once committed, the CVS will automatically update this line, e.g. as follows:

// $Id: file.cpp,v 1.3 2012/03/22 22:41:24 username Exp $

You can also include that in a format as follows:

/*
*====================================================================
* HISTORY:
* -------
* $Log: $
*
*====================================================================
*/

static const char *CvsId = "@(#)$Id$";
void No_Warning_Please(const char *x=CvsId);

A nice webpage and more details on this topic:

http://www.badgertronics.com/writings/cvs/keywords.html

Mount St. Helens Trip, Oregon

Mount St. Helens

The famous (or notorious) volcanic eruption of the Mt. St. Helens in 1980 had been on the headlines for a long time. After 31 years, we did a trip to see the landscape ourselves.

Half Maxwell's Fish Eye Lens - Dielectric Antenna (FDTD Animation )

This video is the continuation of the series on Luneburg and Maxwell's Fish Eye Lenses (dielectric antennas & lenses). Specifically, we demonstrate the electric field propagation through the Half Maxwell's Fish-Eye lens proposed by James Clark Maxwell in 1860 (J. C. Maxwell, Scientific Papers, I, New York, Dover Publications, 1860).

The relative dielectric permittivity of the full Maxwell fish-eye lens drops from 4 to 1 from its center to the edges via the following formula: epsr(r)=4/(1+(r/a)^2)^2 for r less than "a" (and greater than zero) where "a" is the radius of the lens and r is the radial distance from its center. Since the dielectric permittivity is 1 at the edges and slightly increases towards the center, no surface reflection occurs. Half Lens is basically half of the full Maxwell's lens. We have utilized half circles to represent the increasing dielectric permittivity of the lens. Also at the bottom figure, we plot the exact dielectric permittivity distribution of the lens over the space.

In this simulation, propagation through a 10Lambda diameter Half Maxwell fish-eye lens is demonstrated via 2-dimensional Finite-difference time-domain (FDTD) simulations. A point source is located at the a point on the edge of the lens and correspondingly, we observe propagation of a monochromatic sinusoidal source (left) and a short pulse (right) through the lens and onwards. Collimation is clearly observed once the waves emerge from the flat edge of the lens.

References:
A. D. Greenwood and Jian-Ming Jin, "A Field Picture of Wave Propagation in Inhomogeneous Dielectric Lenses", IEEE Antennas and Propagation Magazine, Vol. 41, No. 5, October 1999

How to have two colormaps in MATLAB plots?

A very useful and nice tool to achieve multiple colormaps in MATLAB plots (By John Iversen):

http://www.mathworks.com/matlabcentral/fileexchange/7943

Sample example where the subgraph and the larger graphs have different colormaps: