MathJax

Friday, September 05, 2014

On control and analysis of dynamical systems

  • Even when simple feed-forward control of a linear, time invariant, first order plant was involved, the analysis of the resulting closed-loop dynamics could be involved - the equations becomes linear, time-varying equations.  
  • Once feedback control is involved, the equations become nonlinear and time varying.

Thursday, August 21, 2014

Interesting courses for fall 2014


  • ECON 109 Game Theory
    • MWF 12:00p-12:50p PCYNH 109 Newhouse, Herbert S
  • MAE 281A/B Nonlinear Systems and Control (Prof. Krstic/Cortes)
    • ... Not offered
  • ECE 271A Statistical Learning I
    • TuTh 12:30p-1:50p WLH 2205 Vasconcelos, Nuno 
  • ECE 275A Parameter Estimation I
    • TuTh 2:00p-3:20p PETER 104 Kreutz-Delgado, Kenneth
  • ECE 251C Filter Banks and Wavelets
    • TuTh 3:30p-4:50p WLH 2110 Rao, B
  • ECE 293 Comm. Theory Seminar
    • W 3:00p-3:50p EBU1 4309 Kim, Young-Han 
  • CSE 250 Probabilistic Learning
    • TuTh 12:30p-1:50p HSS 1330 Saul, Lawrence 
  • MATH 245A Convex Analysis
    • MWF 4:00p-4:50p APM 5829 Nie, Jiawang 
  • MATH 271A/B/C Numerical Optimization (Philip E. Gill)
    • ... Not offered
  • MATH 280A Probability Theory 
    • MW 5:00p-6:20p APM 6402 Williams, Ruth J 
  • MATH 286 Stochastic Differential Equations
    • MWF 4:00p-4:50p APM  B412 Schweinsberg, Jason

Wednesday, August 20, 2014

Notes on Clang


  • Clang and LLVM disable RTTI.  As such the object files do not contain RTTI information.
    • ensure the -fno-rtti flag is set

Good questions on C


  • Difference between external linkage and internal linkage
    • default linkage for non-const and const in C
    • use of extern and static keyword
  • Use of unnamed namespace in C++ vs static keyword

Tuesday, August 19, 2014

Building Clang (cont.)

gmake ENABLE_OPTIMIZED=1
Perform a Release (Optimized) build.
gmake ENABLE_OPTIMIZED=1 DISABLE_ASSERTIONS=1
Perform a Release (Optimized) build without assertions enabled.
gmake ENABLE_OPTIMIZED=0
Perform a Debug build.
gmake ENABLE_PROFILING=1
Perform a Profiling build.
gmake VERBOSE=1
Print what gmake is doing on standard output.
gmake TOOL_VERBOSE=1
Ask each tool invoked by the makefiles to print out what it is doing on the standard output. This also implies VERBOSE=1.

Monday, August 11, 2014

Relevant courses in Math Dept.

MATH 271 A,B,C
  • Taught by Professor Philip E. Gill in 2013 (course link)
  • NOTE: Not offered in 2014
  • Offered and taught by Professor Nie in 2014
  • Mostly concepts in convex optimization covered in ECE 273 by Prof. Lanckriet 
  • Offered and taught by Professors {Saab, Leok} in 2014
  • Not sure how applicable this is to the area of optimization 
  • Differential geometric and theory of Lie groups (methods used in the paper by Steven Simon and Aris Moustakas to obtain capacity of MIMO correlated channels)
  • Taught by Prof. Kemp (who also taught Random Matrix theory course)

Monday, July 28, 2014

Thursday, July 17, 2014

HDF5 storage

Look into this when I have a chance

Monday, July 14, 2014

Notes from David and Goliath


  • You have to be "desperate enough" to re-frame your disadvantages into attributes that gives you advantages
  • From AI for the game of Go, statistical (Monte Carlo methods) evaluation may have a better chance of winning when the search space is indefeasibly large.  

Monday, July 07, 2014

Notes on my Ubuntu 14.04 LTS setup


  • Hostname
    • sudo gvim /etc/hostname
    • sudo gvim /etc/hosts
  • Samba server
    • sudo apt-get install samba
    • sudo gvim /etc/samba/smb.conf
    • # Comment out password database stuff
      # Add user name map
         security = user
         encrypt passwords = true
         username map = /etc/samba/smbusers
      
      [homes]
         comment = Home Directories
         browseable = no
         read only = no
      
         create mask = 0644
         directory mask = 0755
      
    • sudo smbpasswd -a user_name
    • sudo restart smbd
  • Apps
    • RStudio (IDE for R)
      • sudo apt-get install libjpeg62
      • sudo dpkg -i rstudio-rel_num-amd64.deb
    • Spyder (IDE for python)

Wednesday, July 02, 2014

Building clang

In case I happen to try this again.  Linking clang is a memory intense task.  I gave my VM 6GB of memory and it is still disk swapping like mad...

Tuesday, June 24, 2014

R cheatsheet


Preliminaries
  • install.packages("package_name",dependencies = TRUE) # install package
  • library(package_name) # load package
  • search() # list all packages attached
  • ls() # list all objects in environment/package
  • help(name) # help on package/function
  • getwd() # get working directory
  • list.files() # list files in working directory
  • save.image() # save workspace to .Rdata
  • savehistory() # save history to .Rhistory
Data types
  • class(obj) # class of object
  • dim() # dimension of matrix
  • length() # length of array
  • factor() # encode categorical variables using numeric storage (e.g. "red","orange","green")

Monday, June 23, 2014

Wish List for matlab parser


Parser features
  • Add parsing of 1-D and 2-D arrays
Param registration
  • Register params
  • Attach to ParseTree
  • Look up value based on hierarchical position of params
Vector dumping
  • Hierarchical file names
  • Header to include attributes and formats

Friday, January 10, 2014

Matlab parser notes

Matlab Grammar

 statements = statements (statements)*
 statement = declare | assign | expr
 clear = 'clear' id';'
 declare = 'global' id ';'
 assign = var '=' ( list | string | expr ) ';'
 var = id('.'id)* | id '(' expr (',' expr)* ')'
 literal = integer | float
 list = '[' expr (',' expr)* ']'
 expr = add_expr
 add_expr = mul_expr (('+'|'-') mul_expr )*
 mul_expr = primary (('*'|'/') primary )*
 primary = '(' expr ')' | var | list | literal | '-' primary

Token definition

 string = '[char]*'
 integer = [0:9]
 float = ...

Operator Precedence

You can build expressions that use any combination of arithmetic, relational, and logical operators. Precedence levels determine the order in which MATLAB® evaluates an expression. Within each precedence level, operators have equal precedence and are evaluated from left to right. The precedence rules for MATLAB operators are shown in this list, ordered from highest precedence level to lowest precedence level:
  1. Parentheses ()
  2. Transpose (.'), power (.^), complex conjugate transpose ('), matrix power (^)
  3. Unary plus (+), unary minus (-), logical negation (~)
  4. Multiplication (.*), right division (./), left division (.\), matrix multiplication (*), matrix right division (/), matrix left division (\)
  5. Addition (+), subtraction (-)
  6. Colon operator (:)
  7. Less than (<), less than or equal to (<=), greater than (>), greater than or equal to (>=), equal to (==), not equal to (~=)
  8. Element-wise AND (&)
  9. Element-wise OR (|)
  10. Short-circuit AND (&&)
  11. Short-circuit OR (||)

Associativity of operators

  • power (.^) is left associative in Matlab

Thursday, January 09, 2014

Compressed sensing notes

  • Classical sampling theory (Nyquist-Shannon framework) 
    • Infinite length, continuous-time signals 
    • Requires the sample at specific point in time 
    • Signal recovery in the form of linear sinc interpolation 
  • Compressed sensing framework 
    • Finite-dimensional vectors in \(\mathbb{R}^n \) 
    • Acquires measurements in the form of an inner-products between the signal and a test function 
    • Signal recovery achieved using highly nonlinear methods

Wednesday, January 08, 2014

Trying out Math on Blogger

The following under determined equation \(Ax=b\) is an example.
Trying \(x_1 = 3\)
\begin{equation} \int_a^b \! f(x) \, \mathrm{d}x \label{eq.gaussian} \end{equation} which we can later refer back to as \eqref{eq.gaussian}.
In equation \eqref{eq:sample}, we find the value of an interesting integral:
\begin{equation} \int_0^\infty \frac{x^3}{e^x-1}\,dx = \frac{\pi^4}{15} \label{eq:sample} \end{equation} Very cool indeed.

Friday, December 28, 2012

Properties of a positive definite matrix

Just found out some interesting properties about positive definite matrices.

Given an Hermitian matrix M

  • The eigenvalues of M is strictly positive.
  • It is the Gram matrix of linearly independent vectors.
  • It has a Cholesky decomposition. M = M' = L' * L = H' * H.  Where L is a triangular matrix with strictly positive diagonal elements.

Sunday, October 07, 2012

Monday, September 24, 2012

Ideal parent of a high reactive child

Quoted from Quiet: The power of introverts in a world that can't stop talking

Someone who can read your cues and respect your individuality; is warm and firm in placing demands on you without being harsh or hostile; promotes curiosity, academic achievement, delayed gratification, and self-control; and is not harsh, neglectful, or inconsistent.


Wednesday, August 29, 2012