Spring 2013 State of the Union

Hello Peeps!  :P

I am happy to report to y'all that I did make it through the thesis defense and that all went very well.  It was originally supposed to be a 40 minute presentation, but I had 50-some slides and so it took me about 65 minutes to get through it.  Since I have spent a few years on the research and analysis, I was hoping that I would get tons of probing questions, but alas, I could only garner 2 questions from the audience (Thanks Uriel)...

I am also very happy to report that I am officially done with my formal schooling!  That is a weird thing to write and an even weirder thing to think through (if you are inside this bear's head), but I am getting used to the idea slowly.

On the topic of significant others, I cannot claim so much success.  Perhaps the Lord is teaching me a lesson in patience at the moment... hard to say.  I guess the only thing is to keep on keeping on.  I have been wondering if I need to change my approach or point of view on things; that is a very hard thing to do since I don't know what to change it to.  Even biblical models are all over the board.  LOL, in any case, I can still find enjoyment in eating and drinking and pleasure in my work under the sun (I've been reading a lot of Ecclesiastes lately). 

I was so happy to celebrate and be a part of my good friend John Miller's wedding last month; that was was nothing short of inspiring.  It is always a refreshing drink to see friends and adopted family in the Petaluma area as well!  :)  John and Ruth (if y'all are reading this), may God grant you two peace and joy!

On a totally separate note, I have now stopped working for the family company (ENE) and have started out on my own by starting my own little engineering firm.  I am hoping to be finalizing my situation and receiving some income soon, but I'll do my best to keep you all posted.  I have to say, working on your own and starting a company with the intent to do that in the long-term is a very different sort of feeling.  I started my business in late February and I have never felt as exposed and vulnerable as I do now.  It is very strange.  It doesn't feel dangerous per se, but there is a very lonely feeling to it (I don't think it has much to do with significant-other-type loneliness, but rather business team-type loneliness).  With that in mind I can hardly wait to increase my team to a number larger than one, but all in good time.  Presently, I just need to survive and figure out how to get ahead of the curve.  :)

Hmm...

One other thing that happened is that my aunt Sharon went to be with the Lord about a month ago.  That was sad news to everyone and she will definitely be missed, but I am glad that she doesn't have to deal with the pain of this world any more.  :)

What else to talk about?  My family is generally doing well, although my dad is still struggling in some areas.  My sister Ashley had her baby "Ada" who is now 4-5 months old I think.  She's definitely a cutie-pie.  My seven other nieces and nephews never disappoint with their unique perspectives on different things happening around them.  What treasures children are, right?

It wouldn't be right to post without some pics, so here are some good shots or things that have happened...

I need to diet more...  look at the size of my head!!  :)

the beautiful view off the porch of my parent's home

one of the revised drafts of my thesis work...  that fish was like 170 pages!  no joke!  :)

my bro Garrett: how does he DO that??  (I don't know, but I can tell you what it smelled like... Death!  LOL)

a beautiful sunrise one morning before I left for work in Orland.

my nephew Case...  this one is a turkey!

Case's argument went he wants to be fed... lol

just a cool car in Chico that I keep forgetting to tell my bro about, haha

The monster pizza that me and the boom's had one night...  this pizza was literally huge... there is no trick lens or effect going on here.  :)

the Case machine is coming along.  gonna get painted and in the field this year!  yay!

gotta love brothers... they are playing with knives and putting each other "in jail" (Zackers and Joshy)

I have had the distinct honor of mentoring a few young men from Hamilton high...  Christian and Adrian.  Here was the whiteboard after a bit of lecture on electronics...  man I love teaching!

Garrett and I set up Ryan's old room as our temporary office.  Here is a rare pic of Garrett working on solidworks!  haha!

there are few who can put the honey on the bread like I can...  just one unique pieces of art that is completely edible.  :P  yum!

my little niece Sadie.  I think... she is up to no good...

Jessa, Hanne, Joshy and Sadie over at the boom's house.  This crew is trouble brewing!

Jessa and Hanne...  what?  do I smell bad?

ahhh.... little Ada...  my mom is a good grandma I think...

papa Nate... there he is!

another good shot of Ada sitting up by herself on the couch with her mommy making her comfy :)

me and Zack hanging out.  more bread art for my hungry public!

This is the "shock cylinder" for the Case machine.  kinda cute, huh?  50,000 lbs of force for 4" of stroke!  yeah baby!

the memories table at my aunt Sharon's memorial service.  I am gonna miss you Sharon.  :)

a breath-taking sunset at my parent's house.  The Lord is the master artist and we are a bunch of phony copy-cats!!

The freak hail/snow that we had in Orland.  that was weird.

another shot of the Case machine, this time with some of the brush-guards in place.

One of my closest friends John Miller, right after he and his bride Ruth were married.  :D

jelly-filled?  anyone?

okay-then... don't mind if I do!  lol!

Bidwell park, 1 mile rec area.  out for a walk with my dad.

doesn't Garrett look a bit like Luke Wilson?

hmm....  that boy can eat!

ahhhhh... back to our hero....  

 

Aight, y'all.  there is a little roll-up of my current events and hopeful directions.  I keep saying i'm gonna try to update this blog more often, but like Mark Twain once said: "I don't have time to write you a short letter, so will write you a long one..."  Until the next long update...

 

Gavin-out.

Thesis Defense Today!!

Hey Peeps!

I promise to give a better update ASAP, but here's the announcment:

Zero Hour is 3 hours away!!  at 4pm, today (Friday, 11/30) I wil be defending my thesis in OCNL 120.  If there is any chance you can make it, come and listen to me drone for an hour or so...  and then... let's party!  LOL  see map in figure 1.

(figure 1: the map)

And... just as a tasty morsel to get you to come on such short notice, check this sweet, sweet figure out!  Wanna know what it is?  Gotta come!!  (or just ask me later, that'll work too, haha)

Okay, that's it for now.  See you on the other side!  :D
G-DOG OUT.

The Number Games

They say that you should always make your title last, after you've completed whatever it is you're gonna write.  I, respectfully, disagree.  I think you should write your title first and then you can know how to stay on track so your mind doesn't wander!  ;)  j/k.

Truly, I am playing number games (and no, this is not an allusion to the movie in theaters).  I have completed something that now must be undone... I need to count down from 248 LBS to a reasonable weight.  That is just WAY to heavy for me.  I think my target will be in the 200-210 range, but I haven't been that weight since high school and I'm not quite sure what's healthy for me yet.  At any rate, I know I can get below 220 and be feeling good, so that (at a minimum) is my target).

On the other side, I have begun something that must be completed.  I began graduate school in Jan. 2009 and I need to button that sucker up.  All that remains is for me to finish research on my thesis and actually write the paper.  Funny thing, that I find it so much harder to find motivation now that I am really doing an academic exercise (the Army Research experiment is completed).  Also, the lack of due dates is really wreaking havoc with my psyche.

speaking of psyche, have you read that book by C.S. Lewis, "Til we have faces"  Psyche is the main female character.  Great book.  ;)

Anyhow, back to the topic of number games, I'm thinking that I'll make those two projects something that I can regularly report on here.  I apologize if you (whoever you find yourself to be) do not care much for my academic and physical goals, but then of course you find yourself here at this blog by your own volition, so my sympathy for you is limited.  :)

Right.  I do promise to report on those two topics, but at least I can derive some motivation from the prospect of public humiliation or lack of progress in the public eye. 

So, in other news about me, I've finally gotten the right license plates on my truck, which is one small step for a screwdriver and nerves of steel, but one giant leap for the legality of my ride!  haha. 

Hmmm.... what else can I update you on?  I was dating a girl named Kristen (see previous post), now we are not dating anymore.  Definitely not parting on bad terms, so that's a plus.  A blog in many ways seems like an inappropriate place for an in depth discussion of this topic, so suffice it to say that I have a huge amount of respect for her and I hope in the future we can continue to be friends and encourage each other. 

I'm excited that I'll be able to head-up an experimental olive harvesting endeavor this fall, which will be lots of fun (and lots of work too).  I think there are significant benefits to the growers and to the custom harvesting companies if everything works out well.  Maybe even some room in the market for some super-high-tech equipment... hint, hint.  LOL.

So here are the numbers for today:
Weight: 248 LBS
Thesis: 1/6 (experiments completed, nonlinear modeling underway)

By way of explanation, I'm dividing the thesis into 6 sections, for simplicity's sake:
1. data from a real process to control (The experiments)
2. nonlinear modeling of the process (math modeling)
3. control design 1
4. control design 2
5. control design 3
6. write the paper

and I did make it to they gym (For the record) yesterday and ran for about 20 minutes.  a good first start.  I also resisted the temptation of having any treats at my parents (and that is no small feat; currently just "sitting around" in the kitchen is two pans of triple chocolate brownies, 3 pans of apple cake and 1 pan of white fudge!!)  I had cereal, spaghetti and eggs/salsa today.  one confession tho: I did forget this morning and I stopped by Java Detour on my way to work and got a hot chocolate and a chocolate bar.  I didn't even think about it until I was driving away.... DOH!  But tomorrow, I'll do better.  If anyone care to weigh in on the topic, what is everyone's thoughts on hot chocolate as something that should/shouldn't be had during a diet?  Anyone?

Lastly, I'll leave you with this:  There is a green field as I look out the window of my truck passing by.  I can decide to frame this field as vacant and lonely or I can frame it as lush and full of potential.  I choose the latter.

That is all for now, peeps.  Keep me posted and I'll keep you posted!
Gavereno.  email: gavin.nielsen@gmail.com if you want to get in contact with me.

Still alive, just paddlin' along

Howdy peeps.

I hope this post finds you all well.  why does it take me so long to post?  Idunno.  I did get a facebook account recently, so I'm posting a bit more there, but this blog is nice because I can post whatever and it doesn't necessarily broadcast it to all my facebook friends.  Understand, it isn't that I don't want anyone there to read this, but sometimes facebook posts tend to demand the attention of one's friends, know what I mean?  This blog, on the other hand, does not necessarily alert anyone when it is updated (unless of course you subscribed to the RSS or atom feeds).  At any rate, for that reason, I feel like I can post more here somewhat more anonymously without subjecting everyone's eyes to my rantings.  Of course, I'll prove myself wrong and post a link to the this on facebook, but somehow it just seems different.  Go figure.

So where I have I been?  I have been working with the family in Orland, CA. as a design engineer for ENE, Inc.  lots of little projects going on there.  Not as many large projects finishing, but I'm working towards things.

I did have some news to report in my personal life though.  I am now dating a wonderful girl named Kristen!  We have known each other for a while, but have recently reconnected.  It is unfortunate that we live a little ways apart (she in Sacramento, I in Chico), but we make it work.  Below is a good picture of us after my last birthday party...  this was the day-after cleanup.  Actually, come to think of it, we were both in pretty good moods considering that we were running low on sleep!  ;)

Anyhow, it has been great getting to know her these last few months (since November).  I suppose this is neither here nor there, but if you haven't tried Mythos beer, you should really check it out; it's good stuff!

Speaking of parties (since I was talking about cleanup) I just celebrated my 32nd birthday on the 17th.  Every once in a while I have a big theme party, and this year was just such a year.  This time I had guests come as an international, historical noun, so I had lots of creatively dressed friends helping me celebrate.  Kristen did a tremendous amount of planning and footwork beforehand and a whole bunch of cookin' the day of.  I don't think she got enough praise for all of her hard work, so I think this is a good place to brag about what a great job she did.  We had food from six different cultures and apetizers from three.  Beer and other beverages spanning those same six cultures as well.  It was great.  The best part was that lots of people came and helped us celebrate, and they all seemed to have a fun time.

Another thing that has happened since I last posted: I bought a truck!  yeah, baby!

It's a 2007 GMC Sierra 4x4.  Man!  It is so nice to be driving a truck again.  Mind you, I'm not saying that I didn't appreciate the loaner vehicles from mom and dad this past stretch, but it feels good to finally have a vehicle that is closer to my personality.  I'm really diggin' the crew cab too.  Now it isn't a pain to invite more people to ride with me...  ;)  It should be noted that my original plan is still in effect: add lift, tires, wheels, sound, etc.  But as is oft the case, things turned out to be a bit more expensive than I anticipated  and I had a bit less cash than I was counting on originally.  All-in-all, I'm very pleased with the purchase though.

Living situation-wise, I am back in Chico living with my brother and roommates.  I had thought for a while that I would try living by myself.  I haven't totally given up on the idea, but I still am thinking that I am a social enough person that I benefit from living with roommates, etc.  So all that is working well.

I have completed the Army AFDD / NASA Ames stuff as far as my project duties, but I am still in the midst of authoring my portion of an American Helicopter Society Forum paper.  That is kind of exciting, expecially since I've never been a co-author (or author) on anything published before.

My thesis is making very slow progress these days, but I intend to crank up the heat on that.  I have to complete the modeling procedures to represent my plant, and then explore a few controller architectures.  This should be straight-forward, but for some (strange) reason, I am trying to get re-motivated to work on it since i'm not getting paid to (funny how that works).  Also, the fact that there is no deadline is really playing tricks on my psyche.

Hmmmm...  what else can I update y'all on... I have spent a good deal of time thinking about mechanical harvesting equipment and the technology surrounding some potential ideas I've had for olive harvesting (in addition to other crops), that I think could knock the socks of people.  I'll have to give some more details on that in another post.

I would appreciate prayer for my family, generally.  We are all going through some tougher times and as at all times, need God's grace to persevere.  Pray that He will give us all peace and endurance.

Personally, I face many upcoming decisions in a lot of areas of my life, and desperately need wisdom that is not of earthly origin.  Please hold me up in prayer as well. 

I'm not sure if this is really a good marketing tactic, but tune in soon to hear some more technical details and my latest schemings; I promise to thrill!  ;)    cya!  BTW, if you wanna drop me a line, send it to gavin.nielsen@gmail.com I'd love to hear from you.

Yeah baby! -> disturbance estimation looking good!

Howdy, ya'll!

It seems like I only blog when I'm back at Ames Research Center, here in the Bay Area.  I had to post something quick 'cause Scott (my cousin) is asleep and I can't tell him right now...  =)  Those of you that know me well, know that I have to get things out of my head and told to someone, partly so that I can stop thinking about it and go to bed, but of course part of it is for your own edificiation.  "Yes," I reply, this does apply to everyone, control theory is general, thus generally applicable.

As a special bonus today, if you read slowly though my monologue and see all the pretty pictures, I will let you see the pictures at the end of some satelite stuff that cousin Scott showed me today.

Right.  Well, here is the state of the union on the helicopter project: I have designed a new, truly high performance controller for the rotor.  This new one uses a more advanced algorithm with an algorithm called receding horizon control or Model Predictive Control (MPC).  Basically, it predicts what the flap will do some steps ahead (15 steps in my case) and then optimizes some "control" commands (5 steps in my case) to make the predicted response as close to what the setpoint reference (my desire) is asking it to do...  In order to do this, it has an internal "sense" of how the model will react to its commands, and then it plans out the next 5 control steps.  When the next control step comes, it does the whole optimization again and plans 5 more control steps ahead. 

When you stop and think about it, this is much like we act every day.  We have a plan of all the wonderful things that we are going to do today and how we will be very efficient with what we want to do.  Then when life actually happens, we have to re-optimize our day as different things come up that make us change our plan.  This controller is just a mathematical version of that.

Example: when you are driving a car, you look forward maybe 50 feet when you are moving slow, right?  you don't plan out what you are going to do and then close your eyes and do it, you watch 50 in front of you, then you drive a little bit and you are still looking 50 feet ahead of you.  This "receding horizon" is the essence of the controller, it optimizes inside a reasonble window of time into the future.

Above is the "natural" response of my system.  This means that when I suddenly tell it to go to the value of 1, this is how it reacts.  My new controller interacts with this natural response and predicts what the system will do, so it can make it settle down quicker.  See below

there are little "steps" in the model output and the command because this is how a computer see the world...  in little steps that are contant between the times that it measure them/changes them.

Anyhow, this new type of controller has the advantage of taking my control bandwidth from something like 15 Hz to now more like 250 Hz.  (not a bad improvement!).  This means that if you ask the little flap to move back and forth 250 times per second, it can and will do what you ask.... fantastic!

The biggest problem at the moment is that while the control bandwdith is great (I only needed to make it to 89 Hz), I still have a low disturbance rejection bandwidth.  disturbance rejection means that when I tell the flap to move to a particular spot and there is something else, external to the assembly that interferes (like aerodynamic forces in my case), how well does the controller deal with that, and at what frequencies will it stop responding.  Up until this point the highest disturbance rejection bandwdith I've been able to achieve was in the 15 Hz neighborhood.  I would really like the controller to be able to get up to 89 Hz disurbance rejection bandwidth to fulfill the purpose that my boss needs it for, so I've been working furiously to try and find a way to accomplish that.

Now, with that context, you can appreciate my accomplishments today (with the Lord's help).  After much research and consideration, I came to the conclusion that much of the problem is seperating what part of the measured position was due to response of the model to my command and what part was due to external disturbances.  This is a tricky thing though, because there is only one position signal that is being measured, so it is combined.  What a wonderful world that we live in that we CAN actually seperate these signals!!  I will not bore you with all the gory math details (unless you ask me of course), but I thought I'd show you some interesting results.  Here is the situation:  I want to control something at 75 Hz.  Meanwhile, some external force is affecting the flap at 120 Hz and then, to really mess things up, gravity is suddenly reduced by 50%, which produces a sudden step in the measured output.  In order to have the flap do as commanded, I have to seperate which parts of what I am measuring come from something that i told it to do (the 75 Hz) and everything else.  Below is a picture of what this would look like.

 So this is the result of my work in the last few days.  The blue is the real thing happening, the red dased line is the system's best guess or estimate about what is going on.  Notice how the guesses are not very good in the beginning but once it locks in, it really a great job!  Now that this portion has been somewhat addressed, I need to figure out what to do with this newly found information in the controller itself (this result is only a small part of the control system; it estimates what is going on that we can't measure directly).  Ideally, the top should be the sum of the bottom two. 

Thanks for hanging with me long enough to get through some cool stuff. 

As promised, here is the super, top-secret satelite pictures that I took when I visited one of the labs that Scott was working in today.  Some of the stuff in this picture is real flight hardware that will be in the final spacecraft.

Objective Successful

I am proud to report that I and the many other people helping me were successful this evening in "closing the loop" of the controller here at Ames.  This means that we can now issue a command to the assembly, say something like, "please oscillate at 35 Hz and at a magnitude of 1 degree."  and it will do so, but you have to say please and ask in a nice voice.  =)

This is a huge step forward for the team in general and for me personally.  This evening marks the first time I have been involved with a closed-loop control project wherein we have gone through the formal experimental and modeling stages and closed-loop control design and had a reasonably high performance controller.  While I didn't get to be involved as much as I would have liked to be in the controller (due to time), I was able to add a modifying controller (an "outer loop") that boosted one of the weaknesses of the inner controller, which was nice to be able to contribute.

One of my mentors, Hossein, and I spent this whole weekend working through the varioius implementation details including safety mechanisms, etc and we finally got the system breathing Sunday evening at about 9pm!  whew!  (the demonstration is taking place at 2pm on Monday...)

This is a funny cartoon kinda showing what closed-loop control is all about, a good reference for those reading this who have no idea what i'm talking about.

Well, I'm gonna hit the hay.  Happy trails partner!

Gavino

one more turn in the bay

Hello everyone!

So after 6 months of hard work at ENE and Army/NASA, I still do not have a finished product to show off, but progress is being made.  I am now back at Ames Research Center in the Bay Area spending about a week to demonstrate some control algorithms for the helicopter blade flap that I've been working on.  Pray that it goes well... if it does then we can continue on our project, otherwise, we will have to give up one of the more challenging tests, which would be a shame.

On the ENE front, the Case machine is coming along nicely (the 6-wheel, fully independent suspension pruning machine).  I have almost completely finished detailing the hydraulic system and my colleague Alex is nearly done with the mechanical design.  I'm very excited about that.  My current estimate is that we will be painting in 4 weeks, put on hydraulics in 5 weeks and be done in about 8 weeks, Lord willing.  I'll definitely post some pictures of that bad boy soon.

On a personal note, I'm still a bit socially constricted due to two (too) busy work schedules (sche-duels).  But every once in a while I get to do something fun and blow off some steam.  I had a wonderful afternoon this last sunday, getting to spend time with some friends I haven't seen in a while (just hangin' out and drinkin' smoothies) and then going to soak up some sun by the pool with family and friends... it was great.  very relaxing.

I still haven't found the truck i'm looking for yet.  I hope to find it soon though.  It's funny, I find the right make/model/year/mileage without the extras, or a find all the extras without the year/mileage...  In case someone reading this (by chance) has my truck, here is what i'm looking for:

chevy silverado
crew-cab
2004-newer
less than 100k miles
4" lift
33x12.50 tires
alloy wheels
the longest short bed (I think it is 6.5')
good paint, good body

so if you have such a truck and are in the market to be rid of it, please drop me a note ( gavin.nielsen@gmail.com )

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

in other news, I'm also looking for a good place to live in the country where I can keep track of a nice big dog...  again, if you have a place, I have some cash!  =)

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I guess last on the list is that other thing, which must not be named.  I daren't say it out loud, for fear that its report may be heard.  No, I must keep it secret, I must keep it safe.  LOL.  This is called dramatic bluffing.  as far as this public address goes, I'm done.  I hope to post some pics soon of the goings on here at Ames, but until then, Adieu!  =)

Gavin

Some poetry from my past

Howdy sports fans!

Today has been a housecleaning/room-cleaning day, and I have had great success!  One benefit to going through things is that you tend to find all sorts of historical treasures (treasures by my measure at least), and today I wanted to share some with ya'll.  I wrote this poem sometime around 1990, so I think I would have been about 10. 

Every Christmas, Thanksgiving and Easter my family makes a massive amount of food.  Do we need all this food?  Probably not, but I guess it is tradition at this point.  Somehow these mountains of food do finally get eaten, sometimes weeks down the road.  LOL.  One of my favorite memories was the competition (when we were younger) to try and steal fudge before dessert time, and this little poem is to that effect.  I hope you enjoy it.

A TASTE OF THE PAST

Some I think of days gone by
I think of me as a little guy.
A man of questions, acquainted with thought.
Thinking of the Christmas war, about the be fought.

Our primary objective was the fudge to robe,
But the restraining dilemma was big uncle bob!
We'd round the corner, innocent as could be,
But he knew our intentions and forced us to flee.

Casey suggested a diversion and I was inclined.
Off went bob, but twas in his arm reclined.
As we watched him go we thought of our plan
And watched with remorse as he dipped into the pan.

It was my turn for an idea and my comrades held their breath
Because my plans of daring usually ended with their death.
To fail was not an option and to quit not a thought;
Fudge was at large, and it wasn't the kind bought.

My plan was perfect.  It had no mistake.
My plan was for Garrett, the fudge, to take.
Garrett wanted to please me, on my every word did he dote,
And he made, by far, the best scapegoat.

We sent out "The Kid" with unprecendented anticipation
For we knew that to succeed meant unparalleled sensation.
Little "G" was sneaky; we had to admit
But compared to uncle Bob, it was bit to bit.

We were linked by walkie-talkies, a clever touch of min.
But really just another tool toward the chocolate taste divine.
Casey took the forward position and I took the rear,
Because if we got caught, Bob'd have them by the ear!

I am a blessed man! =)

Howdy there peeps!

Hmm...  well, here I am with less than a week left in my southbay adventure.  It has been a long ride, but a good one.  reflecting a bit on what has happened since I moved to the southbay, I can't help but thank God for his blessing and provision throughout the year.

I would like to believe that I am a brilliant individual.  Truly I would.  But the reality of the situation is that I feel more like a delivery boy.  Okay, hopefully a delivery man, but you get the idea.  What prompts such a random comment?  I was thinking back on the problems that arose this year at work... definitely some tough ones!  At each step of the way, I feel like the Lord inspired me with ideas to solve the problems as they arose.  Kinda feels like that game ("wack-a-mole"?) where you bonk moles when they poke their head out of a board and you have to bonk them quick or you lose the game.

Enough problems came up this year at work that I truly believe that without the inspiration of the Holy Spirit and the refueling and renewing of my mind, that I might be in mental shambles.  I will not bore you with a list of all of the things, but suffice it to say the list makes me a little tired!  =)

Work aside, it has been a tremendous blessing to live with my cousin Scott.  Beyond just getting to know that chap better, it has been fun goofing off with him.  In some ways we are good for each other since we have some almost opposite tendencies, but then we have a lot in common as well, which makes it fun to talk (and sometimes complain) about work problems since the other can understand them a bit better.

Then there is the whole housing thing...  again, what a blessing!  I got to live in a perfectly central, beautiful apartment complex in Sunnyvale that was very relaxing to come home to (and even had a jacuzzi and pool).  For these last few months I have been blessed to live with Scott in his new home in Santa Clara where I have been the proud occupant of the master bedroom (Scott will soon rent it out, which is why he didn't want to move in there). 

I had the opportunity to get to know a girl from Santa Rosa (Elisa) which ended up not working out, but was still a learning/growing experience for me.  I am often torn when I think back on relationship history-types of things, since all relationships that one invests in that do not work out do take their toll, but thinking back I can praise God that he is teaching me these things so that my future wife will hopefully be shielded from them.  I guess you could say that I have a long way to go, but hopefully I can accelerate and make up that distance fast!  =P  Speedracer!  lol

Since I spent time going back and forth to Santa Rosa / Petaluma, I have had the chance to hang out and have some great talks with one of my closest friends (John).  It is amazing to me that I can know someone for such a long period of time and still misunderstand them.  It would not be appropriate for me to fully explain what I mean by that statement here, but let me just say that I am blessed with close friends who find me worthy enough to share part of their inner-selves with, and this encourages me beyond measure.

On top of all these things (I sure am glad I didn't list the problems, I wouldn't have had room for this list of blessings!)  I have felt much more at peace with my future and future directions, which I would definitely call a miracle in and of itself.  For someone like me who is constantly over-analyzing everything and trying to optimize, feeling at peace with the unknown future and being content to see a few years in advance and settle on a path is no small feat!  Yet, the Lord has seen fit to grant me this insight/direction.  For that, I praise Him! 

I look back and wonder how else I would have come to the same conclusions without spending this time here...  I have often wondered why I am here since I am somewhat isolated and I hate watching my family grow up from a distance.  Don't get me wrong, I knew that I needed to be here to finish my formal education, but one can't help but wonder if there isn't another way when you feel lonely...  But, the Lord has a plan and I am more and more willing to let Him lead and watch the beautiful things that result from letting the omniscient One have the reigns.  How ludicrous that I think I can do better sometimes!  =)

Check back here on the blog soon for an update with some pictures.  I promise to get some pics/videos of the people I've been working with and post 'em (with their permission, of course).  Yet again, a great blessing that I need to praise God for... so many people do not enjoy the people they work with, yet I generally can't wait to get to work and interact with these people (and when I'm not excited to be at work, it is generally because I am tired).

Okay, well that'll do for now, pig.  I hope wherever this post finds you, you are doing well and the ways that you are currently being blessed will be revealed to you also.  "And we know that God causes all things to work together for good to those who love God, to those who are called according to His purpose." (Romans 8:28)

-Gav

On why I love modelling...

Howdy there sports fans!  =)

I am pleased to report that I have had some great success with a long-time project of mine.  I have simulated a very rough approximation of a tree under forced oscillation!  This is something that I have been pondering how to do for about 10 years...  Boy, to write that down makes it seem, well, like a long time.  First, a little backstory...

A few years into college I began mathematically modeling the shaker head that ENE uses for harvesting prunes, pistachios, etc.  After making a few assumptions and idealizations, tt was a relatively simple set of parametric equations, and served as a wonderful application and exercise of the concepts in calculus that I was learning at the time.  Essentially, those equations parameterize the configuration of the shaker head and predict the output pattern.  With a bit of doing (and a few major mistakes in derivation), I had a reasonable, closed-form approximation of how the shaker head would react to different weights, speeds and arm lengths. 

Below is a plot of the predicted output pattern for the configuration
freq1=10 Hz, freq2=7.14 Hz, arm1=2.5 in, arm2=3.5 in, weight1=40 lbs, weight2=30 lbs.

For a while, I was very enthralled by this set of equations and what they might mean for tuning and understanding harveting better, but I soon realized that the real problem was not what the shaker head was doing, but rather how the tree was responding to what the shaker head was doing.  In short, it is necessary to understand the behavior of the shaker head, but only from the standpoint of guiding it into a behavior that is useful for successfully shaking a tree (e.g. getting fruit off, not damaing the tree, etc, etc.).

Since the orginal equations were derived symbolically they are easy to calculate and easy to analyze, but I could not wrap my head around a good method to symbolically model a tree.  As I progressed through my schooling and various work projects, I spent more and more time in numerical simulations (mostly Finite Element Analysis-type (FEA) and dynamical systems (for control system engineering).  It has taken me a long time to realize that the answer to my problem could be approached in a numerical way, but even after I realized that, I wasn't sure the right software package to use to tackle the problem.

****************   so much for the back-story...  on to the present   *****************

Since while I'm here in Santa Clara, I decided that it was the right time to go to a workshop for a software package called COMSOL Multiphysics.  They have an office in Palo Alto which is only a few minutes from work, so it all worked out beautifully.  My cousin scott was nice enough to come along for moral support and may have just enjoyed himself a little along the way...  =)  As part of the workshop, we recieved a trial license for the software which is a great match for my brand-spankin' new computer...  =)

So that was this Tuesday, and for the past two nights I have spent a few hours trying to figure out how to model a tree and simulate it in a flexible way.  This evening I finally had success and thought it would be fitting to share the results of my labor with you.  Below is a very simple tree's response to the input of the shaker head (given the same configuration as listed above).  Hopefully this video uploads correctly... it took a long time, so I'm not sure if everything got to the server ok...

That is pretty cool I think.  The coolest part about this might be that the solve only took about 2 minutes!  Granted, when I have a tree model that is sufficiently more complicated and takes into account more effects (Such as the damping due to leaves, etc.) that solve will take longer, but this was a simple example and it solved very quickly. 

Another quick little video which breezes through the first 50 (or so) eigen-frequencies and eigen-mode shapes (the natural frequencies and vibration modes of the tree structure).  I would slow this down a bit, but the slowest I could do was 1 frame per second, so just check out the frequencies listed in the upper portion of the screen to get a feel of the frequencies that are causing the shapes...

On top of that, I found the COMSOL environment to be very well thought out and even capable of some post processing tasks that didn't need to go over to MATLAB to handle... namely looking at the pattern input that caused this type of purturbation...  I know what you're thinking, you're thinking, "Hey Gav, hang on.  Just a few paragraphs ago you said that you had closed-form equations that could predict the shaker heads position (and thus the pattern input to the tree)..."  to which I respond, "Yes, that's true, but remember my qualification: "After making a few assumptions and idealizations..."  The first assumption was that the shaker head was "free" and not being affected by anything else.  That isn't quite true, because while the shaker head is big and powerful, it is still affected by the tree...  remember, we can push on the tree, but the tree can push back!  So, without futher ado, I give you thee updated pattern that my simulation yielded after taking into account the tree's "push" back on the shaker head...

There are a few things that need be said here...  first of all, you have to look closely to find that it does have many of the same characteristics of the idealized patter, but the idealizations might have been a bit too much from a rough accuracy standpoint.  Note that I didn't include any mass for the shaker head, so this isn't as accurate as it could be.  Also notice that the new pattern output is not as wide as it is tall...  this I believe to be due to the trees asymmetrical response (which in turn is due to it's asymmetrical topology)..  What we found here was that it was much easier to move the tree in and out vs. moving it left and right, which might make sense when you stop and look at where the branches are on this tree...  =) 

Man I love modelling!

*********

On a more peronsal note, I am doing well and things are moving forward with my thesis.  Slowly but surely.  I will post again soon with more personal things, but I better get some sleep tonight!

Thanks for reading!  =)

A title formerly known as "Yes, sort of..."

******
"Comrades!  I am proud to sail with you on the maiden voyage of our motherland's most recent achievement.  Once more, we play our dangerous game... a game of chess against the American navy... only now the game is different..."
******

Had I an orginal thought here I would have opened with it, but as things stand right now, I am very unoriginal.  =P  But I'm working on it. 

I find myself single once again.  I suppose that is a strange thing to mention in a blog, but I feel like saying it, so there ya go.  I suppose that as far as break-ups go, this one was as ideal as they come since both people felt at peace with the decision.  Still, that sort of thing is never very much fun.

Life is definitely different since my last post.  I, my family and many other people were deeply saddened with the loss of a great friend, mentor, father, husband, etc. in Jose Luis E.  I could go on and on because he was many things to many people, but suffice it to say that I am deeply in his debt and his absence will be felt most acutely.

Here in Southbay, I am proud to say that I have made some decisions.  My new plan is to work for the Army up through mid-December and then take two weeks off.  Starting the beginning of January, I will be an ENE employee for most of the week and then for part of the week I will work on Army stuff.  This will be a good balance because I can begin to help with the family business, but still finish the project for my master's thesis (on-blade control-surface closed-loop control on an experimental rotor).  The tentative plan is to graduate in June 2011.

As far as work on that goes, I am very happy to tell that I have made significant progress on several fronts there, and it becomes more exciting the further I go.  Last week I completed my goal of adding specific functionality to the data system ("Dexter"), so that I can now see the frequency spectrum content updated in "GUI real-time" so that I know what is going on, and can see the frequency content (y'know, which frequencies are present in whatever I'm interested in...)  Very cool stuff.  =)  I have also made significant headway on the automation required to make data acquisition and processing streamlined.  The further I go in this development, the more I realize how much automation of mundane tasks really does speed you on your way to a result; often it is the only way to remain sane and get something done!

I was also happy that my funding has now been approved all the way through June, so I can definitely count on that as a plan.  (up until now, it was a tentative plan, but now that approvals have gone through, it is just a matter for me to sign a contract).

hmmm.... what else can I tell you...  Oh!  I'm very excited that I will be getting a new laptop very soon.  I had high hopes of getting an extremely high-end workstation (like $8k) but that purchase gave way to good council and soul searching.  My new system will still be a powerful workstation, but a bit more mainstream and affordable for a bear of small means, such as myself.  Yes, it is true, I have other needs that I could spend money on (perhaps most notably a truck...) but for my current purposes, a laptop is the most pressing need.  I guess for the moment I'll just have to fend off the onslaught of women clamouring for my affection from behind the wheel of a minivan!!  It's tough bein' a sexy soccer mom! lol.

In all seriousness though, I am very excited to save (and spend eventually) for items that might fall in the classification being of more "grown up."  As you've no doubt noticed, I have a penchant for electronics, software and books that is nigh unquenchable, but this old dog is still learning about what is important... Who know, maybe I'll buy myself a house sometime...  but I will not need to invest in a security system, 'cause I can "kick the guns out of their hands!"   =)

I think that pretty well brings you up to date on my goings-on.  This weekend has been pretty chill, so I have had some time to muse and reflect on things.  Here are some of thoughts in a "formatted" version:

-----------------
"That I thought I thought"

That I thought I thought, I thought I knew
that I thought I knew, I built my house
now I shiver in the rain, for my house is cold
but my thoughts are known.

To maintain the house, is on-going;
never finished, never painted.
Its walls are fluid and doors are swung easily,
though they remain transparent, reflection is necessary.

That I harden its foundations, I have before me.
That I maintain its flowing walls, I have ever before me.
But where are the walls affixed the floor?
That that flows, meets the Rock.

This problem eats at my mind, a meal without end.
What when there is no food for feasting?
My hope is ever the Rock, for He is ever constant.
I can trust not the walls, nor the doors, for they move.

Lord, that my mind works, You know.
That I can help, You know.
That I am in need, You know.
That you are not finished with me, I know.

-Gavin Nielsen
gavin.nielsen@gmail.com

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!