Quefrency, Lifters, New House and Fine Dining

Howdy y'all!

So now I'm moved.  Scott and I are settling into the new place and refactoring our organizational methods.  Before I get into the house/food stuff, I wanted to tell you about something kinda cool that I learned today.  Like anything worth learning, this tasty morsel requires just a tad bit of background...

Signal processing is the science/art of modifying or analyzing some sequence of values for useful purposes.  An example might be checking the stock market value of some particular stock every day for a year, then taking those values and taking the moving average of every week of values as they come out to have a better "Feel" of that stock and then making some decision based on it.  Here is a wikipedia article with a little more precise language if you'd like to explore (I would if I were you =)  http://en.wikipedia.org/wiki/Signal_processing

Some more interesting (to me) applications of signal processing are things like filtering an audio signal so that you can turn up the bass and really "bump" in your car or house...  lol.  At any rate, like any technical domain, there are plenty of cool terms and a few that are just made-up because whoever invented it had a good sense of humor. 

For example, in signal processing we talk about the frequency spectrum (a range of frequencies we are interested in), we talk about low-pass filters who "allow" low frequencies through and "stop" higher frequenices (this really kind of a generalization a moving average, when you think about it).

So now to the funny part.  I have been working on a rather challenging filter for a while now (I posted about it a while back), and I keep my nose to the grindstone trying to research and find the right solution to the problem.  Since I had some time today, I was looking at something called the "Cepstrum" which is sort of an odd animal.  its name originates from rearranging the word "spectrum," reversing the first four letters.  I have to tell you the definition because even though it's abstract, it is kinda funny to say (copied from wikipedia):

"verbally: the power cepstrum (of a signal) is the squared magnitude of the Fourier transform of the logarithm of the squared magnitude of the Fourier transform of a signal"
http://en.wikipedia.org/wiki/Cepstrum

lol. But wait!  there's more!  for only $19.99 you can hear the other terms associated with various cepstrum operations!  (okay, fine.  I'll give it to ya for free!)

Instead of talking about time, even though strictly speaking, the unit is time, but we went into the frequency domain and then back to the unit of time but not the time domain) so we are not in the frequency domain either, the independent variable of the cepstrum of a signal is called "Quefrency" (mangled version of frequency) of the signal.  Further, whereas in the frequency domain one has filters, in the quefrency domain there are "Lifters" (mangled version of filters).  Which is another whole pun in and of itself because you can use lifters to "lift" particular frequency components and their harmonics from a signal. 

Let's say that you are recording audio signals and somebody is talking in the room next door.... very annoying.  now you have someone else's voice that you didn't intend to have in your recording.  You can use lifters to lift that voice out of the signal and kinda erase it.  Or maybe you wanna know what the person was saying, then you could isolate it!  Super cool.  I am of course very new to the concept, but it is almost as if the cepstrum is like a second order frequency transform, allowing you to see the spectrum of the spectrum.  Here is a cool pic of a spectrum and the cepstrum of that.

So that was great find for the day.  Thanks for reading though that bit of techy stuff, I hope you enjoyed it.

On another note, my girlfriend Elisa is now in Switzerland on vacation for about 10 days, but before she left she stopped by to see the new place (and maybe to see me too).  Since I had recently failed at a dinner I intended to make, I thought I'd give it another shot and make dinner for both Scott and Elisa...  and the result?  Success baby!  haha, it ended up being very good, in spite of my inexperience.  I fixed penne chicken alfredo with black olives and artichoke hearts, with brocoli, cauliflower and carrots.  2% milk was also available as a beverage.  See, see, see!

I suppose presentation leaves a little to be desired...  all I had were sippy cups and plastic plates and silverware, but I think everyone enjoyed the meal.  That makes me happy.  So that you can see the house, I decided to give you a "flash" tour that wasn't too long.  so I basically ran through the house with my camera.  Here ya go.

And I guess that will conclude my remarks for this afternoon.  I'll be sure to take some nice HD pictures when I get my room more organized and cleaned up.  Until then, via con Dios, my friends!

Dapper dudes, miss-bowled and flexible filtering

Hey there partner!  =)  Glad you took the time to head my direction... 

This weekend was fun.  Elisa came over on Saturday and we had some great talks.  I had promised her a surprise activity, so she thought it was great when we finally arrived at Sunny Bowl in Mountain View to do a little bowling...  here is Sunny Bowl...

Yes indeed, it really looks "Sunny" in there, but you should've seen the look on their faces when I walked toward the door and turned right around seeing that there was no way that they had a bowling alley "in the back!"  =)  I suppose I had the funnier/confused look on my face though.  I should've done my homework a little better!!  Well, we finally did find a place to go bowling (Palo Alto Bowl) and really enjoyed ourselves.  Hopefully you get this quote, but I felt much more like "King of the Lanes" than "King of the Trolls" for this pic...

I think I need to do more manual labor or something because we only bowled two games and my hands were a little sore from gripping the ball...  No good!  =(

Elisa was sure that she could beat me at this game... (we have an ongoing competition when we play games).  As it turned out, I beat her the first game and she beat me in the 2nd.  Just 'cause I'm so proud of our high scores, I thought I'd post the frames for everyone to see (this is for you James!).

It was E-Train vs. G-Dog, and the battle was a fierce one!  I even have the play-by-play for you with this next video, lol

So, we had a good time there.  That was Saturday, on Sunday, I needed to accomplish some things for work, so I have been researching and designing a variable-frequency, variable-order filter to address that problem that I posted a few days ago.  I think I have it conquered, but I wish I could simulate the thing...  that always gives me more confidence.  Here is the rough block diagram

It is kinda neat how variable frequency filters can be realized these days...  the one I'm designing is based on something called "Switched-Capacitors" which emulate resistors.... kinda cool really.  Even though it is an analog filter, it is actually discretely sampled; that is, even though I can put a very precise amount of water in my bucket, I'm still getting a fixed number of buckets every second...  like everything, it is a tradeoff, but with a little pre-filtering, and at high speed "bucketing" (like 100 kHz) I can get very nice looking, accurate filtering done...  way cool.  =)

Lastly on my update agenda is the fact that this is likely my last post from my current abode (in Sunnyvale).  Cousin Scott closes escrow on his home tomorrow, so we'll be moving in this week!  =)  yay!  so next time I should have some pictures of the new place.  In a nostalgic bid to remember this little hat-hanger, I took one last pic of the bathroom...  only because it had two mirrors and I could doubly reverse my reflection and show you the cool new CSUC pride I have!!!   LOL, I'll miss something things about this place, but I sure wont miss the family below us that get in an argument at 11:30pm every evening....  anyhow, here is the new duds

pretty snazzy, right?  Even some nice baller Chico State shorts...  Garrett, you're afraid of these shorts, aren't you?  Well, you should be.  personally, I'd give you one chance in three.  More tea anyone?

Okay, well that's it for now...  one last thought, tho: you should really drink more water, it's sooooo good for you!

What's in a name (or a tree)?

I think this might be a record for my blogging frequency!  Only just yesterday I gave you a lengthy update and here I am back at it again...  =)  too much good stuff to say, I guess.

Since I decided to not work on work over the rest of the weekend, I decided that maybe I'd see if I could make some progress on tree modeling (another back-burner project that's been cookin' for awhile now).  I have been reading about fractals and their recursive nature, and I was inspired that trees seem to show this same nature in the structure as well.  Since it has long been a goal of mine to mathematically model a tree, a logical place to start is to generate the static structure or skeleton of a tree automatically (this takes forever to do by hand).

Today was my first shot at trying to actually implement some code to do this in MATLAB, but low and behold, it worked out alright.  This is only a 2-dimensional version, but you'll get the idea.  It can be easily extended into 3D.  After some trial and tribulation, here is a tree to chew on...  this tree has 3 branches per level and is 4 levels deep.

by changing a couple of numbers, I can very quickly generate a new tree with very different structure...

I am of course still working on the details, so these are only rough-draft trees, but it is exciting to get some visual results so quickly.  Part of why these trees don't look familiar (Beyond the fact that they are perfectly generated and perfectly symmetrical) is that a real tree has gravity acting on it which pull weaker branches down and makes it look a little less upright.  this algorithm is really generating trees that you might think of as having grown upside-down!   of course, it would also help to have thicker lines for the bigger branches, etc.  but all in good time.

 Just a few more variables to throw in their for me to get pictures that will look more like the trees we are trying to model, but this is a good start for today.

I hope y'all have a great week!  G-out

On the state of "Gavin-a-roo" =)

ey there, sports fans!  I am right in the middle of a relaxing Saturday afternoon, so I thought that I'd post an update on how things are going around here...

Work is going well (though one of the other guys in the office remarked that he didn't see too much going "well," rather he saw it as "well, I've got more to do...").  I have to admit, though every project I've ever been involved with gets complicated for reasons that are outside of my control, this project has seemed like a can-of-worms at almost all turns.  I guess that means that I'm learning a lot (which makes me happy), so this is how I replied to my pessimistic co-worker.  =D

Hilary, I haven't yet gotten the approval I need from my supervisor to post the video, so hopefully that will happen next week.  I'll "do it up special" so that it has more footage and better explanations than the other one too!  lol, far be it from me to just "get'r'done".  I guess I use a lot of quotes these days, but "it is what is!"

I can share some things from work.  This last week, I was working on troubleshooting an amplifier and realized that the major problem was not with the amplifier at all (it was due to a  component in my model that was doing exactly what i told it to do).  I was thinking how funny that is that when things aren't going right, we sometimes don't look at ourselves as the culprit until there are no more "outside" places to point at.  Kind of a get-the-spec-out-of-your-own-eye thing (or maybe a you-shouldn't-use-so-many-dashes-thing).

Anyway, after that round of toubleshooting, I had several conclusions.  first that since my system operates at a fixed frequency (somewhere between 4000 and 8000 cycles/second) and the signals i'm generating can range up to rather high frequencies themselves (92 cycles/second under normal conditions and possibly up to 1000 cycles/second) this means that the number of "points" that my system is generating get kinda sparse in the output waveform.  Here's an example.  If I want to generate a nice clean waveform, I'll use a lot of points (500) along it so that is is approximately smooth.

a plot like the one above would happen if we were using a 4000 cycles/second signal generator to generate an 8 cycles/second waveform (4000/8 = 500).  But since my system is generating signals at a fixed rate (approximately 4000 cycles/sec), as we increase the waveform frequency, our points/cycle decreases.  below is a plot of 100 points/cycle.

Notice the "stair-step" like appearance.  This is because we have fewer points, and in-between points the signal generator does not update it output value.  If we push this further to 43 points/cycle (below) we see that the signal is looking less and less smooth.

This is the problem I am running into (one of them at least).  Since my signal is not smooth at higher frequencies, I need to smooth it out after I generate it.  This is done with what is called a "low-pass" filter (which means that it only lets the low frequencies pass through it and attenuates the higher frequencies).  In the picture below I have made a cool Simulink model (part of MATLAB) which does two things: it generates exactly the same signal as my data system (my data system was prorammed using the same code), and then it simulates what effect a proposed analog low-pass filter would have on that generated signal.

Here is the plot this model produced (below)

See how nice and smooth the red is?  very nice!  =D  So I've been playing a little with that today, trying to find a reasonble filter design to handle my needs (the output amplitudes are similar, as in this one, but also the phase shift can't be too much, notice how in this one the red output signal is shifted to the right...)

Yeah, so that's what I've been working on lately.  There are some other cool things that I've been playing with, but I'll save 'em for later.  In other news, I have been thinking a lot about a new truck!  It has been awhile since I have really seriously considered buying a new vehicle, but things are at a points where it seems reasonble.  I have been doing some research on it (that is what I do, I guess), and come up with the following spec that i'm looking for: 2007 chevy silverado extended cab, 1/2-ton, supersport, lifted with 35x12.50 tires and nice alloy wheels.  With a little snooping around on the net, I found a picture of *almost* exactly what I'm looking for...   :P

Wow, that's pretty, eh!  So I've been pursuing that a little and watching some different ads to see if I come across anything interesting.  It is so strange to actually have some money to think about these things, I'm really not used to having any money!  :P

On the topic of money, I've also been thinking about a killer workstation laptop.  This isn't a popular idea with any of my advisors, but man, how sweet would it be!  For those of you that are into the techy stuff, I'm thinking about a Lenovo W701, 2GHz, 16GB RAM, 256GB ss hard drive, 1TB secondary, 17" uwxga display (FHD, LED backlit), blu-ray burner onboard, Quadro 3800 video card with 1TB of memory.  Pretty much maxing everything out the way I like it there.  Of course, the major problem is that it is so stinkin' expensive.  Ah well, for the moment, dreaming is free...

On another front altogether, I have made  some great strides in my eating habits this last week.

This here picture is a sandwich I made for myself at lunch.  Now, mind you, making food is not all that difficult a task, so I'm not expecting a bouquet of roses, but for some reason I have something of a mental block about making my lunches, cooking at home, etc.  this week I only eat out twice; both times because I needed something to eat for lunch and I didn't have time to make it the night before or the morning of.  Other than that, this week has been completely "homemade."  Yay!!  ...and there was great rejoicing!

There is often more going on that I can't blog about, but there is a similar phenomenon that there is more blogged about than you are interested in, so I think it balances itself out.  I'm missing all you friends and family out there, but I'm trying to be content in my situation and take full advantage of it.

Oh, one other thing.  I almost forgot to tell you...  I have changed a little!  See if you can find the difference in these next too pictures (queue the music, "one of these pictures is not like the other")

And of course, my post wouldn't be complete without mentioning that I've been having a great time with my girlfriend Elisa.  This pic was taken before we went out to eat a few weeks ago... it's funny, the stairs do a tolerable job of holding the camera, but I still can't get them to take it where I look as good as she does!  Oh well, I guess I'll just keep workin' on my guns and hope for the best!  =P

Adieu!

As usual, after the disorder, the post...

At the behest of my younger (and wiser) sister, I come to you again.  It has indeed been quite a while since I've updated the old bloggy, but a fair amount has transpired since the last time, so an update I will post.

Back a while now (Sometime in late Feb, early April) I started dating a girl from Santa Rosa...

Her name is Elisa, and I kinda like her (just a little bit though)  =)

We both like exercising, and sometimes we help each other out...

Lol.  Sorry, I had to post this one.  It's funny cause if I claim to be strong, then I'm implying she's heavy (which she isn't), but if I claim she's light, then I have no claim to strenth (and who would want to claim that!!)...  hahaha.  What a fun way to workout!  =)

Strength and weight aside, we have a great time together.  This last weekend, (July 4th weekend) I had the pleasure of spending 4 days with Elisa and her family at their place in Tahoe, which was lots of fun.  Unfortunately, I completely forgot my camera, so I don't have any pics of the trip to post...  = (   fortunately, there were other cameras there, so hopefully I'll be able to get my paws on those later, but for the moment, they are memories that are only in my head.  We spent some time floating around on rafts near the dock, took some bike rides around the area and even got some reading done (fractals, baby!  I really should get some fiction books though).

At work, I am steadily moving closer to finishing my thesis.  I have moved past the theory and have been elbow deep in bench testing various circuit and hardware.   Here are some pics of the various tests that I've been workin' on...

(I need to check and make sure the picture can be posted)

This pic (above) is my test setup of an isolation circuit that I designed...  and it works!  =)  that's always a good thing, don't you think?  This little darling let's you connect with something that is "floating" 1500V above or below where you are, and not damage either side...  kinda cool actually.  And it accomplishes all this magic optically (Light Emitting Diodes to send the signal (LEDs) and Photo-Detector Diodes to recieve it (PDDs)).

This next circuit is my most current setup.  It is kinda gettin' crowded on the  bench, eh?  ;) 

(I need to check and make sure the picture can be posted)

This setup is allowing me to pump some power through resistors (located on the shiny heatsink in the middle) and some capacitors (inside the black box, so they don't blow up in my face).  The rack on the left is a set of instrumentaiton amplifiers, and the setup on the right is the power supplies, the power amplifier, and my isolation circuit in the shiny aluminum case.  This test was to find out how "well-behaved" the power supplies and amplifier really are.

I designed the cooling setup (sort of) and simulated it to make sure that I had sufficient cooling capacity for my situation.  That makes some pretty pictures, so I'll show you one.  This is actually using muffin fans instead of a squirel cage fan like you see in the pic above, but the same idea.

I am now nearly ready to start on the "real" data of the atual actuators and do some real experimental work.  I am hoping it goes well, and definitely hoping it goes quickly, but either way, I'm sure I'll learn a lot.

So....  Who cares, right?  what's "really" going on in my life besides girlfirend and work.  To be honest those two things take an inordinate amount of time.  Not time that I begrudge, but still...  lots of time.  In related news, I did upgrade to a new phone.  I got one of 'em fancy phones, the Motorola "Droid."  That has been fun, downloading all sorts of silly little apps like a "soundboard" of quotes from Zoolander or Charlie the Unicorn.  Also, more serious apps like the Star Trek soundboard.  Now, whenever some emails or texts me, I am greeted with a cool little computer beep followed by Spock saying, "Captain, incoming message."  lol.  gotta love Star Trek, right?  Then there are the somewhat useless but fun to show off apps like Google Goggles which are very handy for identifying things that you already know that they are (it can read bar codes and occasionally gets a painting right).  I'm not meaning to sound negative at all.  There are some really useful apps, like the map app, which uses GPS and can get me whereever I need to go and the browser app which lets me surf the web and figure stuff out without my computer.  Yeah, gadgets are good.

Garrett, you will be happy to learn that i have not increased my bench lately, but I have started do dumbell press (inclined and standard) and liftin' some hefty bells.  That's what reall worker-outers call 'em...  Bells.  =)  Didja see what I did there?  I left off the "dumb," cause, well it doesn't sound as cool.  Right.

Nate, you will be happy to know that I have now gone on a 22 mile  bike trip (Tahoe to Squaw Valley and back).  Man, you really don't realize which muslces are gonna be sore! But I wasn't feelin' too bad afterward, I definitely needed a little break though!  :)

Mom, I'm trying to eat healthier, and I think to a large extent I am succeeding.  I have gotten completely burnt out on Arby's...  so that kinda helps in a wierd way.  =)

Ash, thanks for the reminder to keep this little beauty up to date.  I fully intend to, but sometimes I don't accomplish my intentions.  =)  thanks for the update on you blog as well, I read it and it was very nice

Just a quick aside, I had vanilla pudding tonight for dinner.  I usually skip dinner, so it was just a fun treat.  Don't worry, 2% milk, and sugar free pudding, so I can maintain my feminine figure.  lol.

Hm.....  What else to say...   I guess that's pretty good for now.  As always, I will try to be more consistent with my blog updates.  There are times (as everyone knows) that my life just doesn't seem all that interesting to the outside world from my perspective, but I'll give you a boring post now and again, just to make sure you've had your "Gavin Fix" for the period.  ;)

With that, I bid you adieu.  Family and friends, I love and miss you guys.  When I left, I was but a cabin boy; when I return, I will be a cabin man.

Yours very truly,

Gavin

P.s.  just for fun... a little video that I captured on my camera.  Don't show it to the police...  hahaha  I was bored (back in March sometime) and was playing with the video options on my phone.  This little drive is where I often go to grab groceries, chinese, pizza and movies.  (not all at the same time usually though).  I really am a safe driver, I swear!  lol

P.p.s. these videos take forever to upload!

A few fun pics and work update

Howdy.

Last weekend I had some visitors since Leanne's b-day party happened in S.F.  On account of that, Garrett stayed with me here at my place while they stayed in a hotel in the city.  Now, seeing as I now have a shiny new camera, I had to "test out" some new features and when better than when my little bro is in bed??!  :P

First, I'll give you glimpse of the tired crew that came to my pad soooo late... (past Scott's bed time)

When all the ladies left, Garrett and I talked for a bit (between the pounding of our noisy neighbors....  we weren't being loud, but the apartment has relatively thin walls).  The we slept, and the next morning, wonder of wonders, I was up and moving before little bro.  Now, I'm warning you, these are very rare pictures of a sleeping Garrett in the wild, so don't just go giving these out to anyone... :)

Much to my surprise, Garrett had been coated with a shiny new coat of paint during the night.  The bandits who did this didn't do a real good job though (see how they just shot him from the top?)

At first the little dog was a little scared to be in a photo shoot so early.  Here you can see his inner feeling amplified by my new camera.  Everyone is "yella" sometimes...

That shade of fear quickly evolved into a darker shade of emotion: embarrasement.  I told him that he should not be so embarrassed and pretend I'm not here.  So he went about the normal morning task of eating yogurt in bed.  Between you and me... I think he was still a little embarrassed... the camera doesn't lie.

Finally, after much persuasion and practice, he shed his fears and embarrassment to be the Garrett i know: the Garrett who is larger than life and whos lively color outshines the surroundings he's placed in.....   I don't know what to say about that expression though.  Quite frankly, it's a little disturbing, but gotta love the bro!

So that's it for the wacky morning pics, but I thought I would share kind of an interesting pic from work.  I have been "hunting" for the right model of the phenomenon happening in the dynamic system that I am modeling.  Late this week, I saw my first glimpse of that model in kind of a neat way.  This pic below is a rendering of a possible surface that represents the hysteresis (or "lagging behind") of my system compared to the input.  Kind of neat looking surface I thought.  Who knew I'd be constructing landscapes while I was here?!?!

This is kind of neat thing.. .to visualize something that you've only seen in your mind's eye and on academic papers....    I wont go into detail regarding what everything represents, 'cause that would probably be a little boring, but for those of you who have read some of the things I've written, the "left-to-right" dimension is "alpha", the "front-to-back" dimension is "beta", thus the triangular section of beta vs. alpha is the Preisach plane.  The height of the surface represents the gain of a particular hysteron in the plane.

Okie-dokie, I guess that's just about enough math stuff.  Thanks for taking the time to read my blog and catch up on what's happening in my life.  ;)

Laterz->Gav

New Camera!!! Hoo-rah!

What a lovely Friday this is!  Well, in order to motivate myself to blog a bit more often, I decided that I need a better tool for describing my life...  a shiny new camera!  For those of you who are curious about the specs, it is a canon SD3500 "point and shoot" type of camera (14MP, 5x optical zoom, IS, 720P movie mode).

I am very impressed with this little camera.  Sure, it isn't near as fast as my Rebel, but I can't fit the rebel in my pocket either!  :)  on top of that, this camera has a very cool feature: the back of the thing has no buttons... only a 3.5" touchscreen!  wow... i was gambling with this one to see if i'd like it.  So far, I'm very impressed.  I had assumed that the low light performance would be marginal, but as you'll see from these first shots, it doesn't do too badly at all (our whole house is low light 'cause we're too cheap to buy more lights).  This is a typical evening in our newly-chair-populated living room.  Cousin Scott is relaxing in one of the all-American lounge chairs. 

And here is our kitchen.  This shot is looking the other way in the house.  See?  we now have a table!  What a huge difference that makes!  My room is down at the end of the hall...  Scott's room is halfway down the hall, then up the stairs on the left.

So, if you go all the way down the hall and poke your head into my room, this is what you'll find.  Lot's of whiteboards and lots of books!  The window actually looks out on a rather nice scene, but since it is now dark, you really can't appreciate it in a picture tonight.

Finally, we have a great shot at the spaniard himself, Scott-E.  The man is getting ready to go to bed.  We were going to go to the movies tonight, but I flaked out.  This week has been crazy busy.

So I guess that's it for the pics.  I shot a funny video with Scott too, but I don't have a quick way to get that onto the blog right now since it's in HiDef.  As far as other updates go, I'm officially registered for graduation (Thank you Mom!!!)  and my grad clearance form should now pass muster as I added a one-unit course to fulfill the 30 units necessary for graduation...  I'm gonna work on a DSP algorithm to do object tracking, which should be a lot of fun.  Maybe I can post some of the cool tracking footage on here so you guys can get a glimpse of "the light."  And, just in case there was any doubt, when I say "the light" I mean the fun business of DSP and digitial signal analysis...  gotta luv 'em! :P

Ok.  Well I think we're back up to speed.  Oh, btw, my thesis is going well and I now have 8 weeks to turn it in.  It should be noted at this point that I have 0 pages written.  Time to start crankin' i think!  Take care.  Gavin out.

***** Late Breaking Update  ******

I did find a quick way to get the video up here... the built in windows video editor... and now without further ado, I give you scottE!!  

-----

okay, well that ended up being a dud.  for some reason the upload video button has disappeared from my little WYSIWYG toolbar here in the editor.  what a bummer.  I'm sure I'll figure it out later.  Have a good night, peeps.  --Gav