Disbaling bluetooth on boot up - ubuntu 12.04

Run sudoedit /etc/rc.local and add this before line with exit 0:

rfkill block bluetooth

You should still be able to enable Bluetooth through the top bar applet.

Source

Back up slides in Latex

 To have back slides in latex and not screw up the slide numbering, do this.
 1. Add these after your \usepackage{} lines, before \begin{document}
  \newcounter{sauvegardeenumi}
  \newcommand{\asuivre}{\setcounter{sauvegardeenumi}{\theenumi}}
  \newcommand{\suite}{\setcounter{enumi}{\thesauvegardeenumi}} 

2. Then, as below.
\begin{frame}

Your last slide...

\end{frame}
% BACK UP SLIDES
\newcounter{finalframe}
\setcounter{finalframe}{\value{framenumber}}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{frame}
.
.
.
\end{frame}

\begin{frame}
.
.
.
\end{frame}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\setcounter{framenumber}{\value{finalframe}}
\end{document}

Setting up website on server at IITB

Paste all your files in the public_html folder.

if you can't do that. run
~$ ls -l
and see if have ownership rights on the folder. If you dont, send a email to admin[at]ee[dot]iitb[dot]ac[dot]in and ask them to give you those permissions.

Once you can copy into the folder, you are almost done.
go to - http://www.ee.iitb.ac.in/student/~loginname/

If your CSS file is not loading, then ssh to your account from a terminal, then run
~$ chmod -R 755 public_html

(the -R is very important)

Should be all working now.

Peace.

Increasing number of workspaces

For Ubuntu 12.04, with gnome session fallback

To increase the number of workspaces,

gsettings set org.gnome.desktop.wm.preferences num-workspaces 8

Peace.

Latex related links

Writing a pseudo code-
http://tex.stackexchange.com/questions/163768/write-pseudo-code-in-latex

Getting the algorithmx package
http://www.latex-community.org/forum/viewtopic.php?f=54&t=21070

Post graduate study in Germany

Few details from a seminar I attended on the topic.
1. No tuition fee. Scholarships available enough to pay for lodging and travel.
2. Deadline for application - 2nd October. Entire process is online.
3. Few important links.
    www.daad.de
    www.daad.de/international-programmes
    www.daad.de/research-explorer
    www.phdingermany.de
    www.research-in-germany.de
    www.funding-guide.de
   Major institutions - Maxplanck Society, Leibniz association, Helmholtz association.
4. Resource person in Mumbai
    Shubhada Choudary
    c/o UHDE India pvt ltd.
    3rd floor, A wing,
    Jolly board tower,
    I-think techno campus,
    Station Road, Opposite Crompton Greaves
    kanjur Marg East,
    Mumbai 400042
    mumbai@daadindia.org

Genius Child by Langston Hughes

This is a song for the genius child.
Sing it softly, for the song is wild.
Sing it softly as ever you can-
Lest the song get out of hand.

Nobody loves a genius child.

Can you love an eagle,
Tame or wild?
Can you love an eagle,
Wild or tame?
Can you love a monster
Of frightening name?

Nobody loves a genius child.
Kill him - and let his soul run wild.

-Langston Hughes

Solution : System time conflict between ubuntu and windows.

1. Open terminal

2. type the command
~$ gksudo gedit /etc/default/rcS

3. In the gedit window, edit the BIOS clock section to what is below.

 # assume that the BIOS clock is set to UTC time (recommended)
UTC=no

4. Save and exit.

Source. 

Serial Communication Register details. AT89C5131

Scilab - resource document.

http://kiwi.emse.fr/SCILAB/sci-bot/sci-bot.pdf

Closing all scilab figures with one command

I observed that to close all figure windows in scilab, we can't use
>> close all
like in MATLAB.
After looking around, got the equivalent command in scilab. It is,
>> xdel(winsid())

peace.

Apostrophe in latex

If you want use apostrophe in your document and it isnt showing in the built pdf file, include fontenc package.

\usepackage{fontenc}

Running a python script from the python shell

To run a script from the python shell or the python prompt, use the command

>> execfile('filename.py')

To clear the screen, do the following,
>>import os
>>os.system("clear")

These are for systems running Ubuntu. Not sure if this will work for other operating systems.

Some more more more more GRE words.

61. Guileless - free of deceit.
62. Supplant - move into the position of
63. Vilify - Spread negative information.
64. Vile - morally low.
65. Insidious - working in subtle but destructive way.
66. juxtapose - place side by side for contrast.
67. Eclectic - Comprised of a variety of styles.
68. Forlorn - showing hopelessness.
69. avaricious - excessively greedy.
70. Tantamount - essentially equivalent to something.
71. Haughty - arrogant.
72. ephemeral - lasting a very short time.  

Some more more more GRE words.

46. Precociously - exceptionally early maturity.
47. Ameliorate - make something bad better / improve state of something
48. Panache - distinctive and showy elegance.
49. Languid - slow and relaxed.
50. travesty - mockery.
51. spurious - plausible but false.
52. Apathy - absence of emotion.
53. delineate - describe in detail.
54. vehement - extreme intensity of emotions.
55. immutable - not able to be changed.
56. heretic  - holding unorthodox opinions on any field.
57. contrive - to pull of a plan or scheme.
58.Quotidian - found in the ordinary course of events.
59. refractory - stubborn to control or authority.
60. Mollify - to pacify someone.

Some more more GRE words.

31. Eschew - stay away from / avoid deliberately.
32. Impudent - rude.
33. Decorous - Good taste in manners.
34. Gossamer - Characterized with unusual lightness and delicacy.
35. Reticent - reluctant to draw attention to yourself.
36. Culpability - State of guilt.
37. Didactic - excessively instructive.
38. Bucolic - relating to the pleasant aspects of the country.
39. Apathetic - Lack of interest.
40. Deferential - showing respect.
41. Perfidy - act of deliberate betrayal.
42. Inexorable - impossible to stop.
43. Engender - to give rise to
44. Belligerent - eager to fight.
45. Ascetic - practicing self-denial.

Some more GRE words.

16. Conspicuous - completely obvious.
17. Preclude - prevent from happening.
18. Germane - relevant.
19. Glut - excessive supply.
20. frivolous - not serious in attitude/content/behavior
21. audacious - willing to be bold in social situations.
22. Chortle - to chuckle in a muffled, breathy way.
23. Gall - trait of being rude.
24. Vociferous - conspicuously and offensively loud.
25. mawkish - overly sentimental to the point that it is disgusting.
26. aesthete - someone who appreciates beauty of art and nature.
27. concede - to accept defeat, surrender.
28. Torpor - inactivity resulting from lethargy.
29. Prescience - Power to foresee the future.
30. superfluous - add no value, serving no useful purpose.

Some GRE words

1. Demur - to object or show reluctance.
2. veracious -  truthful.
3. Disinterested - unbiased / neutral.
4. Tirade - long angry speech of criticism or accusation.
5. Galvanize - to excite/inspire.
6. Acrimony - bitterness and ill will.
7. Enervate - to sap energy from.
8. Profligate - spending resources recklessly or wastefully.
9. ingenuous - to be naive and innocent
10. censure - to express strong disapproval.
11. auspicious - favourable.
12. Platitude - obvious remark.
13. trite - lacking originality or freshness.
14. Gainsay - deny / contradict / oppose.
15 - Apathetic - Lack of interest.

Excerpts from "An Essay concerning Human Understanding" by John Locke.

Will be continually updated as i proceed through the book -

1. For the understanding, like the eye, judging of objects only by its own sight, cannot but be pleased with what it discovers, having less regret for what has escaped it, because it is unknown.

ISR addresses for 8051 microcontroller

SPI in AT89C5131 - configuration tables

Some definitions used in graphs

A walk  : Sequence of vertices and edges v_i and e_i such that for 1 <= i <= k, the edge e_i has endpoints v_(i-1) and v_i.

The length of a walk is the number of edges in it.

A trail  is a walk with no repeated edges.

A path is a walk with no repeated vertex.

fact - path be a trail, but path may or may not be a trial.

The distance d(u,v) between vertices u and v equals the shortest length of a u,v path.

A circuit is a closed trail.

A cycle is a closed path.

A graph is connected if any two of its vertices are joined by a path.

 A tree is an undirected graph in which any two vertices are connected by exactly one simple path.

Laplacian matrix of a graph

The incidence matrix of an oriented graph -
Orientation of a graph X is the assignment of direction to each edge.
An arc of a graph is an ordered pair of adjacent vertices.
Formal definition -
       An orientation of X can be defined as a function sigma from the arcs of X to {-1,1} such that, if (u,v) is an arc, then sigma(u,v) = -sigma(v,u).

Let D be the incidence matrix of the graph X.
The laplacian of X is the matrix Q(X) = D*D'
Laplacian does not depend on the orientation.

Q is symmetric => its eigen values are real.
Its positive semidefinite => evas are all non-negative.

TREES - The number of spanning trees is determined by the laplacian.
[Spanning tree - The spanning tree of a connected undirected graph G is a tree that includes all the vertices and some or all of the edges of G.]

Let e = uv be an edge of X.
The graph obtained by deleting the edge e is denoted by X \ e. Its edge set is denoted by E(X) \ e.
Vertex set remains the same.
contracting the edge e => X / e.

Consensus algorithms. part II

Consensus - when the individuals agree on the value of a variable of interest, they are said to have reached consensus.

To achieve consensus, there must be a shared variable of interest, called the information state,  as well and consensus algorithms for negotiating to reach consensus on the information state.

Examples of information state -  local representation of the center and shape of a  formation, the rendezvous time, the length of a perimeter to be monitored, the direction of motion for a multivehicle swarm and the probability that a military target has been destroyed.

By necessity, consensus algorithms assume only neighbor to neighbor interaction between vehicles.

Fundamental Consensus algorithms. - 
Basic idea - impose similar dynamics on the information states of each vehicle.
Information state update is modeled using a differential equation or difference equation depending on type of communication.

Consensus algorithm algorithms in cooperative control. Part I

Motivation for cooperative control -
greater efficiency and operational capability than autonomous vehicles on solo missions.
Applications -  space based interferometers, combat, surveillance and reconnaissance systems, hazardous material handling, distributed reconfigurable  sensor networks.

Concepts in cooperative control -
Formation control, rendezvous, attitude alignment, flocking, foraging, task and role assignment, payload transport, air traffic control and cooperative search.

Challenges -
1. develop a system of subsystems rather than single system.
2. The communication bandwidth and connectivity of the team. - unreliable channels, what, when and whom to communicate with.
3. team goals and individual goals should be negotiated.
4. Limited computational resources in each individual vehicle.


Common assumptions done -
1. availability of global team knowledge.
2. ability to plan group actions in a centralized manner.
3. proper communication among the individuals.

Axiom -  Shared information is a necessary condition for cooperation.
Information exchange is the central issue in cooperative control.

Coordination information/ coordination variable - the information that is necessary for cooperation.

The objective is to determine algorithms that can ensure the convergence of the coordination variable to pre-specified values in presence of
1. imperfect sensors.
2. communication dropout.
3.sparse communication topologies.
4.noisy and unreliable communication links.

Basics in graph theory

The content here is same as the wikipedia entry at this link. I am just writing this as i can't seem to concentrate by just reading.

Complete graph - all possible pairs of vertices are adjacent or the degree of all vertices is |V|-1.
k-regular graph - every node in a graph with n nodes has the same degree k<= n-1.
Line graph - the line graph of G, denoted as L(G),  is the graph where the edges of G correspond to the nodes of L(G), and  two edges in L(G)  are adjacent if they share a node in G.

The adjacency matrix - The adjacency matrix A(X) of a directed graph X is the integer matrix with roes and columns indexed by the vertices of X,  such that the uv-entry if A(X) is equal to the number arcs FROM u TO v.
The spectrum of graph X is the set of eigen values  of A(X) along with their multiplicities.


Cycles are of two types.
1. Closed walk - sequence of vertices starting and ending at the same vertex. Its implied that the vertices are adjacent  to each other.
2. Simple cycle - closed walk with no repetition of vertices or edges allowed, other than the starting vertex.

Tree - is an undirected graph in which any two vertices are connected by a simple path.
Spanning tree - The spanning tree of a connected undirected graph G is a tree that includes all the vertices and some or all of the edges of G.

Vector spaces defined on a graph - vertex space, edge space, cycle space, cut space.

My Movie playlist

There are some movies that I keep watching over and over. some of them are,
1. Revolver(2005)
2. V for vendetta(2005)
3. MindGame(2004) (Japanese)
4. Pi(1998)
5. Waking Life(2001)
5. My fair Lady(1964)
6. Monty Python and the holy grail(1975)

Have got a new list of movies from my friends. hopefully will update this soon.

Exporting simulink model as a image

in the command window,
>> orient('myModel','portrait'); % can use landscape. based on the model
>> print -dpng -r300 -smyModel filename.png

done.

Debugging the DSO board

Our DSO board arrived. We are using two Atxmegas. One for ADC and USB communication. The other for waveform generation.
Now, for some reason the input at PA1(input to ADC) is giving us problems. The external input is scaled and shifted using opamps and then given to ADC pins. i.e., PORTA. This is so that the pins of the controller are not given voltages outside the absolute voltage specifications (-0.5V to 3.3V).

28 feb -
found out that PA0, 3.3V and ground volt were shorted.
i was "being stupid".
There was no short. Amaldev had to come all the way from his lab to verify that.
One day, he is gonna snap and throw  me in front of a running bus.

Anyways, on burning the final code we had written, the voltages at PA1 and PA2 are getting stuck at 2.1V.
On burning our earlier ADC codes, there is no problem.

Resolved. In a file included by the example project, on which our entire project stands on.

IF

I found this poem while reading inspirational comics on zenpencils.
Then searched for this awesome poem by Rudyard Kipling, titled 'If'
Posting it here.

If you can keep your head when all about you   

    Are losing theirs and blaming it on you,   

If you can trust yourself when all men doubt you,

    But make allowance for their doubting too;   

If you can wait and not be tired by waiting,

    Or being lied about, don’t deal in lies,

Or being hated, don’t give way to hating,

    And yet don’t look too good, nor talk too wise:

If you can dream—and not make dreams your master;   

    If you can think—and not make thoughts your aim;   

If you can meet with Triumph and Disaster

    And treat those two impostors just the same;   

If you can bear to hear the truth you’ve spoken

    Twisted by knaves to make a trap for fools,

Or watch the things you gave your life to, broken,

    And stoop and build ’em up with worn-out tools:

If you can make one heap of all your winnings

    And risk it on one turn of pitch-and-toss,

And lose, and start again at your beginnings

    And never breathe a word about your loss;

If you can force your heart and nerve and sinew

    To serve your turn long after they are gone,   

And so hold on when there is nothing in you

    Except the Will which says to them: ‘Hold on!’

If you can talk with crowds and keep your virtue,   

    Or walk with Kings—nor lose the common touch,

If neither foes nor loving friends can hurt you,

    If all men count with you, but none too much;

If you can fill the unforgiving minute

    With sixty seconds’ worth of distance run,   

Yours is the Earth and everything that’s in it,   

    And—which is more—you’ll be a Man, my son!

Great blog post I came across.

As I was browsing around I found this post shared on Facebook - https://medium.com/life-learning/2a1841f1335d

Really great one. Got me thinking.
I will just put up the headings. Read the entire post at that link.

7 Reasons why you will never do anything amazing with your life

1 :: Because You Have Not Failed Enough

2 :: Because You Care What Others Think About You

3 :: Because You Think You Are Smarter Than You Are

4 :: Because You Don’t Read

5 :: Because You Lack Curiosity

6 :: Because You Don’t Ask Enough Questions

7 :: Because You Can’t Handle The Truth

Read the entire article here.

The orginal article here.

 

 

 

 

 

 

Modelling of systems

Modelling of systems is the first step in doing everything with the system.
If you have modeled a system, then you know exactly how the system is going to behave or not going to behave when it receives specific inputs.
So, if you don't know how the system acts then, there is no way you can use it and make it do whatever you want it to do. Everything system that we can interact with and understand how it is going to react is modeled in our heads. What you do not understand, you cannot model, or can we?!
There are 3 different ways in which systems are modeled.
One is from the laws of nature or white box modelling.
You know the forces acting on the system and you have the laws that these forces follow. Then, you know all you need to know.
Two is, grey box modelling.
Here we know the inner workings of the system partially. Some part we do not know. Its also called Semi-deterministic model.
Three is black box modelling.
Here, we don't know what is inside the system and its inner workings. The system is like a opaque black box which cannot be opened.  You just have places where you can give your inputs and places where you can see the outputs. From this we need to find out the relation between the inputs and outputs. Plus, the systems we usually encounter are dynamic, which means the way its going to act now depends on what input it was given earlier. i.e., we have to find the relation between the current output and current input, earlier input, earlier outputs.

Its clear to me that I myself am not clear with these things, because I cannot seem to be able to write with much confidence.

Signed Binary representation and mathematical representations

Two methods to begin with.
1. Sign/Magnitude representation
2. Ones complement method

Sign/Magnitude method : The leftmost bit is sign bit and remaining bits represent magnitude.
MSb is 0 for negative numbers and MSb is 1 for negative numbers.
Therefore we have +0 and -0. Not efficient.

One's complement method : the negative of a number is its ones complement(I expected something better).
therefore if 0 = 00000000, then 11111111 is -0. 1 = 00000001 and -1 = 11111110

Both these are not good enough, have drawbacks.Hence we have the Twos complement method.
That is negative of a number is its 2s complement(surprisingly simple).

Examples -  +1 is 00000001. to get -1, take ones complement : 11111110, then add 1 : 11111111
                  therefore -1 = 11111111

Same method can be used to convert -ve number to +ve number to find out the magnitude.
for example, the value of 10100011 is found like this -
take ones complement - 01011100
add 1 : 01011101. this has magnitude 93.
therefore 10100011 = -93.

Here too, the MSb points to the sign of the number.

Reference - http://www.swarthmore.edu/NatSci/echeeve1/Ref/BinaryMath/NumSys.html

Cause and Effect

Cause and Effect is only of the most dastardly laws. Totally hate it.
Its so plain and straight forward, like simple mathematical axioms, you just can't argue with it. Damn.
I can't get good grades without studying, nor can i build muscles without going to the gym.
That's cause and effect for you, in action.

I wonder, if it would be possible to interchange the causes and the corresponding effects by employing some kind of system in the middle! there should be some kind of controller in between which routes the causes to its effects. If somehow, i can get my hands on this controller, it would be great.

Till then, no choice.
Rise and Grind.
Everyday.

As a man thinketh

Quotes from this age old book which intrigues me.
1. A man only begins to be himself when he ceases to whine and revile, and commences to search for the hidden justice which regulates his life.
2. Law, not confusion, is the dominating principle in the universe.
3. Men imagine that thought can be kept secret, but it cannot.
4. Selfish thoughts of all kinds crystallize into habits of self seeking, which solidify into distressful circumstances.

Finally a poem at end of chapter 1.

You will be what you will to be;
Let failure find its false content
In that poor word, "environment,"
But spirit scorns it, and is free.

It masters time, it conquers space;
It cows that boastful trickster, Chance,
And bids the tyrant Circumstance
Uncrown, and fill a servant's place.

The human Will, that force unseen,
The offspring of deathless soul,
Can hew a way to any goal,
Though walls of graphite intervene.

Be not impatient in delay.
But wait as one who understands;
When spirit rises and commands,
The gods are ready to obey.

Epic lines!!!