The Selfish Gene

The idea of culture-evolution via "meme" is interesting. The idea of extended phenotype is also intriguing.

Great Science Talks

1. A talk on how bacteria perform group action.
2. A talk on the scale and contents of our universe.
3. A talk on an interesting topic: "fight against ageing".
4. A talk on visual illusions.
5. A talk providing a bird's eye view of the nature and implications of ideas in String Theory.
6. A talk on the current state of WiTricity or wirelessly transmitted electricity (no wires!).
7. A lucid talk on an idea about the origin of scents.
8. A talk on how we come to possess strange beliefs.

Euler's Mistake

He started with the equation x/(x-1) + x/(1-x) = 0,

rewrote it as 1/( 1-(1/x) ) + x/(1-x) = 0,

found power series for both functions and concluded:

... + 1/x^2 + 1/x + 1 + x + x^2 + ... = 0.

The conclusion is false as taking x = 1 makes it:

... + 1 + 1 + 1 + 1 + 1 + ... = 0.

The mistake is as follows:

1/( 1-(1/x) )'s power series is a geometric series which converges when

abs(1/x) less than 1, or abs(x) is greater than 1.

And, x/(1-x)'s power series is a geometric series which converges when

abs(x) is less than 1.

No value of x let both of them to converge at the same time.

On Evolution

A list of books on Evolution and Creationism:

1. Berra, Tim M. 1990. Evolution and the Myth of Creationism.
2. Eldredge, Niles. 2000. The Triumph of Evolution and the Failure of Creationism.
3. Futuyama, Douglas J. 1983. Science on Trial: The Case for Evolution.
4. Kitcher, Philip. 1982. Abusing Science: The Case Against Creationism.
5. Montagu, Ashley (ed.). 1983. Science and Creationism.
6. Newell, Norman D. 1982. Creation and Evolution.
7. Peacocke, A. R. 1979. Creation and the World of Science.
8. Ruse, Michael. 1982. Darwinism Defended.
9. Young Willard. 1985. Fallacies of Creationism.

A nice set of video lectures on Evolution.

A fabulous video course on Evolution, specially the 2nd (why we should keep evolution and religion separate, at least for now), 4th (simple things can produce remarkably intricate designs without any "understanding"), and 9th (evolution and brain, a great presentation) lectures.

Two great worlds

We, humans, are supposed to be in about midway between the very small (inner world of atoms) and the very large (galaxies and beyond) in terms of scale. We are mostly unaware of the extraordinary events going on in the world of minuscule beings (let's keep out the atoms, rather ponder about small life-forms) and in the world of giants. Two instruments, a microscope and a telescope, can give a glimpse into the two worlds which are fantastically bizarre from our everyday world. Why should we miss the fun?

Programming for iPhone

1. The work of handling various buttons and labels in a Window-based application gets delegated to a class called project-nameAppDelegate. In this class methods should be defined to respond to actions that take place in the iPhone's window, such as the pressing of a button or the movement of a slider. This class will also have instance variables whose values correspond to some control in the iPhone's window, such as the name of a label or the text displayed in an edible text box. These variables are called outlets, and like the action routines, in Interface Builder, those instance variables have to be connected to the actual control in the iPhone's window.

Core Motion Framework

• There are 8 header files - they can be grouped into four categories: Initialization (CMMotionManager.h), Reporting (CMError.h, CMErrorDomain.h, and CMLogItem.h), Combined Motion Sensing (CMDeviceMotion.h), and Individual Motion Sensing (CMAccelerometer.h, CMAttitude.h and CMGyro.h).
• After creating an instance of CMMotionManager, an application can use it to receive 3 types of motion: raw accelerometer data, raw gyroscope data, and processed device-motion data. The processed device-motion data provided by Core Motion's sensor fusion algorithms gives the device's attitude and rotation-rate; the direction of gravity, and the acceleration the user is imparting to the device.
• An application can take one of 2 approaches when receiving motion data: by handling it at specified update intervals or periodically sampling the motion data.
• For handling motion updates at specified intervals, the following 3 steps should be taken: (Step:1) set accelerometerUpdateInterval property in the unit of seconds, (Step:2) call startAccelerometerUpdatesToQueue: withHandler:, passing in a block of type CMAccelerometerHandler, and (Step:3) accelerometer data is passed into the block as CMAccelerometerData. Similar 3 steps should be taken for Gyroscope or Device Motion.
• For periodic sampling of motion data, the following 2 steps should be taken: (Step:1) call startAccelerometerUpdates, and (Step:2) periodically access CMAccelerometerData objects by reading accelerometerData property. Similar 2 steps should be taken for Gyroscope and Device Motion.
• The availability of hardware and its activity status are accessible through the following 2 properties: accelerometerAvailable and accelerometerActive. Similar 2 properties are there for Gyroscope and Device Motion.
• CMAccelerometerData has a struct type property called acceleration (CMAcceleration) which contains 3 double's for the accelerations along the 3 axes in the unit of G's (gravitational force).
• CMGyroData has a struct type property called rotationRate (CMRotationRate) which contains 3 double's for the rotation rates around the 3 axes in the unit of radians per second. The sign follows the right hand rule: if the right hand is wrapped around one of the axes such that the tip of the thumb points toward the positive direction of that axis, a positive rotation is one toward the tips of the other fingers.
• CMDeviceMotion encapsulates measurements of the attitude, rotation rate, and acceleration of a device. There is a catch: the accelerometer by itself actually measures the sum of two distinct acceleration vectors: gravity and user acceleration; user acceleration being the acceleration that the user imparts on the device. Due to the fact that Core Motion is able to track a device's attitude using both the gyroscope and the accelerometer, it can differentiate between those two acceleration vectors, namely gravity and user acceleration. The 2 properties: gravity and userAcceleration, correspond to them. In toto, CMDeviceMotion has 4 properties: attitude (CMAttitude type, orientation of the device relative to a given frame of reference), gravity (CMAcceleration type, a vector expressed in the device's reference frame), rotationRate (CMRotationRate type, contains a measurement of gyroscope data whose bias has been removed by Core Motion Algorithms and is different from CMGyroData that gives raw gyroscope data), and userAcceleration (CMAcceleration type).
• CMAttitude represents a measurement of the device's attitude at a point in time. It offers 3 different mathematical representations of attitude: a rotation matrix (as rotationMatrix property of type CMRotationMatrix), a quaternion (as quaternion property of type CMQuaternion), and Euler angles (in radians, as roll, pitch, and yaw properties). Roll is a rotation around a longitudinal axis that passes through the device from its top to bottom, pitch is a rotation around a lateral axis that passes through the device from side to side, and yaw is a rotation around an axis that runs vertically through the device and this axis is perpendicular to the body of the device, with its origin at the center of gravity and directed toward the bottom of the device. CMRotationMatrix is of struct type and it contains 9 double's representing 9 entries (m11 through m33, e.g., m31 is the element in row 3 and column 1) of a 3-by-3 rotation matrix. CMQuaternion is also of struct type having 4 doubles (x (a value for X-axis), y, z, and w) in it. A quaternion offers a way to parameterize attitude. If q is an instance of CMQuaternion, mathematically it represents the following unit quaternion: q.x * i + q.y * j + q.z * k + q.w and a unit quaternion represents a rotation of theta radians about the unit vector {x, y, z} and {q.x, q.y, q.z, q.w} satisfies 4 relations: q.x = x * sin(theta/2), q.y = y*sin(theta/2), q.z = z*sin(theta/2), and q.w = cos(theta/2). CMAttitude class has a crucial instance method called, multiplyByInverseOfAttitude which takes in a CMAttitude object and multiplies its inverse with the receiving CMAttitude object and it replaces the receiving object with the change of attitude with respect to the passed-in attitude object. In order to use a CMAttitude object as a reference, it must be cached and passed as an argument to this method in subsequent calls.
• CMLogItem is a base class for Core Motion classes that handle specific types of motion events. Objects of this class represent a piece of time-tagged data that can be logged to a file. It has a read-only property called, timestamp, of type NSTimeInterval which records the time when a motion-event measurement was taken.
• CMErrorDomain has a NSString in it called, CMErrorDomain and it identifies the domain of the NSError objects returned from Core Motion.
• CMError is of enum type which currently (description is forthcoming, says the library reference!) has one value defined in it called, CMErrorNull = 100.

General Theory of Relativity

1. Accelerated frame of reference is described by a transformation to a curvilinear co-ordinate system.
2. Physical laws in a uniform gravitational field is identical to those same laws expressed in an accelerated frame of reference (or a curvilinear co-ordinate system).
3. Tidal force is the obstruction to replacing a non-uniform gravitational field with an accelerated frame of reference. Curvature is the obstruction to describing a non-flat surface with the rectilinear co-ordinates. There is a connection: tidal force originates from the curvature of space-time!
4. Einstein's Law of Gravitation has two parts in it: (part: 1) how the geometry of space-time changes when matter is present - namely, that the curvature expressed in terms of the excess radius is proportional to the mass inside a sphere and this law should be true in any moving system (Einstein's Field Equation) and (part: 2) how objects move if there are only gravitational forces - namely, that objects move so that their proper time between two end conditions is a maximum (Einstein's Equation of Motion). The three discrepancies from Newton's Law of Gravitation, first derived by Einstein have been experimentally confirmed: The orbit of Mercury is not a fixed ellipse; starlight passing near the sun is deflected twice as much as you would think; and the rates of clocks depend on their location in a gravitational field. Whenever the predictions of Einstein have been found to differ from the ideas of Newtonian mechanics, Nature has chosen Einstein's.
   

Special Theory of Relativity

Galilean transformations imply that all physical laws remain identical in uniform motion. If the Galilean transformations are inserted into Maxwell's equations, they do not remain identical [Problem:1]. Moreover, Maxwell's theory concludes that a disturbance in the electromagnetic field travels at the same speed (speed of light) in all directions even if the source of the disturbance is moving. Michelson-Morley's (M-M) experiment shows that velocity addition theorem does not work for light [Problem:2]. In order to solve the two problems, Lorentz devised a set of transformations. Under Lorentz transformations Maxwell's equations remain identical, and the length contraction (required by the transformation) account for the null result in the M-M experiment. Einstein said, all physical laws are identical under: not Galilean, but Lorentz transformations. And that's it.

Recreational Experiments

1. Build a Foucault's Pendulum and prove that the earth is rotating.
2. Perform Cavendish's experiment for finding out the Gravitational Constant.
3. Perform Romer's Experiment for finding out the speed of light from observing the moons of Jupiter.

Excerpts from Advice to a Young Scientist

1. ...they should have more than one string to their bow and should be willing to take no for an answer if the evidence points that way.
2. ...if once a scientist experiences the exhilaration of discovery and the satisfaction carrying through a really tricky experiment - once he has felt that deeper and more expansive feeling Freud called the "oceanic feeling" that is the reward for any real advancement of the understanding - then he is hooked and no other kind of life will do.
3. Most able scientist I know have something for which "explanatory impulsion" is not too grand a description. Immanuel Kant spoke of a "restless endeavor" to get at the truth of things, though in the context of the not wholly convincing argument that nature would hardly have implanted such an ambition in our breasts if it had not been possible to gratify. A strong sense of unease and dissatisfaction always goes with lack of comprehension. ...Perhaps the restless unease I am writing of is an adult equivalent of that childish fear of the dark that can be dispelled, Bacon said, only by kindling a light in nature.
4. ...application, diligence, a sense of purpose, the power to concentrate, to persevere and not to be cast down by adversity - by finding out after long and weary inquiry, for example, that a dearly loved hypothesis is in large measure mistaken.
5. The novice who tries his hand at research and finds himself indifferent to or bored by it should leave science without any sense of self-reproach or misdirection. ... A scientist who pulls out may regret it all his life or he may feel liberated; if the latter, he probably did well to quit, but any regret he felt would be well-founded, for several scientists have told me with an air of delighted wonderment how very satisfactory it is that they should be paid - perhaps even adequately paid - for work that is so absorbing and deeply pleasurable as scientific research.
6. A graduate student should by all means attach himself to a department doing work that has aroused his enthusiasm, admiration or respect; no good will come of merely going wherever a job offers, irrespective of the work in progress.
   
7. It can be said with complete confidence that any scientist of any age who wants to make important discoveries must study important problems. Dull or piffling problems yield dull or piffling answers. It is not enough that a problem should be "interesting" - almost any problem is interesting if it is studied in sufficient depth.
8. Isolation is disagreeable and bad for graduate students.
9. Because the newly graduated Ph.D. is still very much a beginner, a new migratory movement has grown up in modern science that is spreading as rapidly as the at one time newfangled habit (deplored in the Oxford of my days) of taking Ph.D.s at all. This new movement is the migration of "postdocs." Graduate research and attendance at conferences usually gives graduate students powers of judgment that they often wish they had had before they embarked on their graduate work. Later on they will know a great deal more than they did at first about the places where really exciting and important work is going on, preferably in congenial company. To one or other such group the most energetic postdocs will try to attach themselves. Senior scientists welcome them because as they have chosen to come they are likely to make good colleagues; for their part, the postdocs are introduced to a new little universe of research.
   Whatever may be thought about the Ph.D. the treadmill, this new postdoctoral revolution is an unqualifiedly good thing, and it is very much to be hoped that patrons and benefactors of science will not allow it to anguish.
   
10. The great incentive to learning a new skill or supporting discipline is an urgent need to use it. For this reason, very many scientist (I certainly among them) do not learn new skills or master new disciplines until the pressure is upon them to do so; thereupon they can be mastered pretty quickly.
11. Too much book learning may crab and confine the imagination, and endless poring over the research of others is sometimes psychologically a research substitute, much as reading romantic fiction may be substitute for real-life romance.
    
12. The beginner must read, but intently and choosily and not too much.
13. It is psychologically most important to get results, even if they are not original. Getting results, even by repeating another's work, brings with it a great accession of self-confidence; the young scientist feels himself one of the club at last, can chip in at seminars and at scientific meetings with "My own experience was ..." or "I got exactly the same results" or "I'd be inclined to agree that for this particular purpose medium 94 is definitely better than 93," and then can sit down again, tremulous but secretly exultant.
14. ... imaginative guesswork that is the generative act in science.
15. ... their spouses are in the grip of a powerful obsession that is likely to take the first place in their lives outside the home, and probably inside too; they may not there may not then be many romps on the floor with the children and the wife of a scientist may find herself disproportionately the man as well as the woman about the house when it comes to mending fuses, getting the car serviced, or organizing the family holiday.
    
16. To be creative, scientists need libraries and laboratories and the company of other scientists; certainly a quiet and untroubled life is a help.
17. An ambitious young scientist is marked out by having no time for anybody or anything that does not promote or bear upon his work.
18. The ambitious make too obvious a point of being polite to those who can promote their interests and are proportionately uncivil to those who cannot.
19. The traditional reason given for a scientist's reluctance to write a paper is that it takes time away from research; but the real explanation is that writing a paper - writing anything, indeed, even the begging letters that are necessary if a laboratory is to remain solvent - is something most scientists know they are bad at: it is a skill they have not acquired.
20. The only way to learn how to write is above all else to read, to study good models, and to practice. I do not mean to practice in the sense in which young pianists practice "The Merry Peasant," but practice by writing whenever writing is called for, instead of making excuses for not doing so, and writing, if necessary, over and over again, until clarity has been achieved and the style, if not graceful, is at least not raw and angular.
21. In writing a paper, a young scientist should make up his mind about whom he is addressing. The easy way out is to address one's professional colleagues only - and of them, only those who work in a field cognate with one's own. This is not at all the way to go about it. A scientist should reflect that his more intelligent peers probably browse in the literature for intellectual recreation and might like to find out what he is up to. The time will come, moreover, when a young scientist will be judged upon his written work by referees and adjudicators. They are entitled to feel annoyed - and often do - when they can't make out what the paper is about or why the author undertook the investigation, anyway.
    
22. A formal paper should therefore begin with a paragraph of explanation that describes the problem under investigation and the main lines of the way the author feels he has been able to contribute to its solution. Great pains should be taken over the paper's summary, which should make use of the whole of the journal's ration of space (one-fifth or one-sixth of the length of the text, as the case may be), and its composition is the severest test of an author's literary skill, particularly in days when "precis writing" has been dropped from the syllabus in most schools for fear of stifling the scholars' creative afflatus.
23. A summary must be complete in its own limits. It may well start with a statement of the hypothesis under investigation and end with its evaluation.
24. The number of references cited in the literature list (be always scrupulously careful to observe the house style) should be that which is sufficient and necessary; it may be a symptom of scientmanship to quote references from journals published so long ago that librarians desperate for space have long since had them stashed away in the galleries of disused mines.
25. ...experiments are very often designed not in such a way as to prove anything to be true - a hopeless endeavor - but rather to refute a "null hypothesis."
26. Observation is a critical and purposive process; there is a scientific reason for making one observation rather than another. What a scientist observes is always a small part only of the whole domain of possible objects of observation. Experimentation, too, is a critical process, one that discriminates between possibilities and gives direction to further thought.
27. In real life it is not like this. The truth is not in nature waiting to declare itself, and we cannot know a priori which observations are relevant and which are not; every discovery, every enlargement of the understanding begins as an imaginative preconception of what the truth might be. This imaginative preconception - a "hypothesis" - arises by a process as easy or as difficult to understand as any other creative act of mind; it is a brainwave, an inspired guess, the product of a blaze of insight. It comes, anyway, from within and connot be arrived at by the exercise of any known calculus of discovery.
28. A hypothesis so permissive as to accommodate any phenomena tells us precisely nothing; the more phenomena it prohibits, the more informative it is.
29. ... falsification is a logically stronger process than what sometimes people rather recklessly refer to as "proof"...
30. A scientist is, then a seeker of truth. The truth is that which he reaches out for, the direction toward which his face is turned. Complete certainty is beyond his reach, though, and many questions to which he would like answers lie outside the universe of discourse of natural science.
31. ... an ambition that a scientist can always achieve: he can try to understand.
32. Science will dry up only if scientists lose or fail to exercise the power or incentive to imagine what the truth might be.
    

Heroes

I have been in love with the lives of Ramanujan, Einstein, and recently Michael Faraday.
Ramanujan was an Indian mathematician. He lived for only about thirty odd years, during the years connecting the nineteenth and the twentieth centuries. He was self-taught; mostly by proving the theorems in Carr's book. He was picked up by the famous English mathematician G. H. Hardy and was then known throughout the world. He was not philosophically deep and diverse by the way, his only love which seems to be on the edge of obsessiveness was what is now known as Number Theory. It was a romantic story anyways.
Einstein is known to all, more or less. His is one of the few great names in science. His passion was Physics. He was neither a prodigy nor extraordinary in his academic standing. He did his principal works during the beginning years of the twentieth century. He was a patent clerk then. He studied physics during his poly-technique life being indifferent to any other subject and continued studying during his time as a clerk. During his adolescence, he stumbled upon an idea: what would light look like if one could travel with it side-by-side? Light then should have seemed to be standing still, but nowhere he could find the description of a standing wave. He intermittently thought about the problem and ultimately in 1905 among other three important works proposed his revolutionary solution to the Aether mystery which has been called The Special Theory of Relativity since then. Later he extended this theory to incorporate acceleration and it was known as The General Theory of Relativity. In a sense, he too, was self-taught and worked out of pure passion.
While reading The Grand Design by Hawking, I have known some personal stories of Michael Faraday. He had to quit school at the age of thirteen and worked as a book-binder. The books he had to tend, were his source of learning. He did simple and cheap experiments out of curiosity. Later he was able to discover the influence of magnetic field both on electric charges and on polarized light, hitting upon the clue that all of these: electricity, magnetism, and light; are intimately connected. Besides, he fathered the concept of force field which had been the principal way of explaining how forces act upon bodies at a distance, till now. It is a treat to see how, on an overarching glass plate, the iron fillings get oriented (one or two taps to help them to win over friction) exactly according to the magnetic field extending between north and south poles of a magnet. He lived and worked during the first half of the nineteenth century. He also was self-taught and passion-driven.

Programming in Objective C

• In Objective C, setter and getter methods are automatically generated by the compiler if @property (in the interface file, .h) and @synthesize (in the implementation file, .m) keywords are used.
• Every instance variable is protected by default.
  
• Objective C has the garbage collection mechanism built into it, but not all platforms support it, e.g., iPhone.
• A variable defined outside a method is not only a global variable but it is an external variable also. To make a variable global within the file, but not externally accessible, the keyword, "static" should be used.
• #ifdef DEBUG along with #endif is a neat way to contextually switch on or off all the debugging statements embedded inside the source.
• The default return type of a function is "int" whereas that for a method is "id". Functions are external by default, in order to restrict access to it, the keyword "static" should be used.
  
• Foundation framework has NSString class to work with strings. There are immutable and mutable strings. NSNumber is the class for working with numbers. Similarly NSArray is the class to be used when arrays are to be used, and there are mutable and immutable arrays. NSMutableArray is a subclass of NSArray (immutable).
• Dictionary is a collection of key/value pairs. It can be mutable or immutable. For a mutable dictionary, entries can be dynamically added and removed. Dictionaries can be searched on a particular key, and their contents may be enumerated. The keys must be unique and they can be of any object type, typically strings though. The value associated with a key can be of any object type except for nil.
• A Set is a collection of unique objects, it can be mutable or immutable. Operations on a Set includes: searching, adding, and removing members (valid for mutable sets); comparing two sets; and finding union and intersection of two sets.
• NSFileManager lets one to work with files. The available operations are: create a new file, read from an existing file, write data to a file, rename a file, remove (delete) a file, test for the existence of a file, determine the size of the file along with other attributes, make a copy of a file, and test two files for the equality of their contents. Operations such as create, read, or delete can be performed on directories. It is possible to link files, i.e., the same files can exist under different names or even in different directories. To open a file and perform multiple reads and writes on it, NSFileHandle's methods are needed. NSFileHandle enables one to open a file for reading, writing, or updating; seek a specified position within a file; and read or write a specified number of bytes from or to a file. The methods from NSFileHandle can also be applied to devices or sockets.
• About program 16.1 (Programming in Objective C 3rd Edition): The current working directory while running the program in XCode is build/debug, so the testfile must be there. Methods such as: copyPath: toPath: handler:, movePath: toPath: handler:, fileAttributesAtPath: traverseLink:, moveFileAtPath: handler:, removeFileAtPath: handler:, and stringWithContentsOfFile: have been deprecated; these methods must be replaced with: copyItemAtPath: toPath: error:, moveItemAtPath: toPath: error:, attributesOfItemAtPath: error:, removeItemAtPath: error:, and stringWithContentsOfFile: ecoding: (e.g., NSUTF8StringEncoding) error: methods.
• For program 16.3: Use createDirectoryAtPath: withIntermediateDirectories: attributes: error: method to create the new directory.
• Autorelease pools are distinct from built-in garbage collection, therefore, iPhone still has access to autorelease pools even though it doesn't support garbage collection. An object can be attached to the NSAutoReleasePool by sending "autoRelease" message to it, but doing that does not change its reference count. Reference count of an object is automatically handled while adding and removing to or from a collection (e.g., an array); in other cases the programmer has to keep track of the count explicitly in order to ensure that the system will actually free up the memory. Every "retain" message to an object increases the reference count by 1 and every "release" decrements it by 1. When an object is created its reference count is set to 1. If the reference count of an object comes down to 0, the system frees up (calls "deallocate") the memory. All in all, creation of an object must be paired up with a "release", and every intermediate "retain" must be paired up with an intermediate "release".
• Constant strings have no mechanism for counting references, they can never be released. The value of the "retainCount" of a constant string is the largest possible unsigned integer value, or UINT_MAX (for some systems the largest possible signed int value, INT_MAX), in the standard header file limits.h.
• Assigning a copy of an object using copy or mutableCopy method to another object reference is called "shallow" copying; it is equivalent to assigning a reference of the first object to the reference of the second one. If the object being copied is a collection of objects, then subsequent changes to the original object or its copy affect both of them, because they both point to the same memory locations. To break the tie between them, "deep" copying is required.
• In order to have a copy method for your class, copyWithZone: (NSZone*) and/or mutableCopyWithZone: (NSZone*) must be implemented. The "Zone" argument enables you to work with different zones of the total memory for your program which might be useful for programs that allocate a lot of memory. The idea is to optimize allocation by grouping them into zones.
• Saving an object to a file and reading it back can be performed in two ways: property lists and key-valued coding. NSString, NSDictionary, NSArray, NSDate, NSData, or NSNumber objects can use writeToFile:atomically: method to write contents to a file. In case of writing out a dictionary or an array, this method writes the data in the format of an XML property list (plist). When you create a plist from a dictionary, the keys in the dictionary must all be NSString type objects. The elements of an array or the values in a dictionary can be NSString, NSArray, NSDictionary, NSData, NSDate, and NSNumber type objects. For reading back data from a file, you can use one of these methods as it fits: dictionaryWithContentsOfFile:, arrayWithContentsOfFile:, dataWithContentsOfFile:, and stringWithContentsOfFile: .
• NSKeyedArchiver, on the other hand, provides more flexibility: one can save and read any type of object with it. Here an archived object acquires a key, and for retrieving the object from the archive this key is used. iPhone does allow it.
• In order to save and read objects of one's own classes, one has to provide encoder and decoder in those classes. "Deep" copying involves archiving. The idea is to archive from the source object to a NSData or file and then unarchive to the new object.

Interesting libraries in iOS 4.0

iOS 4.0 has two nice libraries: Core Motion Framework and Accelerate Framework. I am interested in developing an Inertial Navigation System on iPhone which will use the phone's accelerometer and gyroscope data and these two libraries seem quite useful.
In Core Motion Framework, an instance of CMDeviceMotion encapsulates measurements of the attitude (phone's orientation with respect to a frame of reference), rotation rate, and acceleration of a device. Core Motion can give user acceleration (free from the acceleration due to gravity). Moreover, CMRotationRate property contains a measurement of gyroscope data whose bias has been removed by Core Motion Algorithms. The identically named property of CMGyroData, on the other hand, gives raw data from the gyroscope.
Accelerate Framework has been provided to facilitate mathematical computations. It contains C APIs for vector and matrix math, digital signal processing, large number handling, and image processing.

Reading...

I was going through the books in the shelf and came across a book by Naipaul. I was familiar with his name, since my eldest brother had a few of his (Naipaul's) novels in his collection. I also knew that Naipaul was a Nobel laureate, but this book, titled "In A Free State," I borrowed from the library for it won Booker. Previously I liked "Life of Pi" and grew a liking for Bookers. There were three stories in "In A Free State." I started reading the second one from midway, this is the first time I started reading a book from a random page. I liked the familiar setting of the story, "Tell Me Who To Kill", the characters and settings were Indian. The style is direct and lucid. I also liked the story, "One Out Of Many." It also was about some Indian. In both of these stories, the protagonist tries to escape his miserable state of life and fails. I started reading the last and the longest story, "In A Free State", but did not like it. It was set in Africa during a time of political unrest. I stopped reading the book.

I have borrowed, "The Perennial Philosophy" by Aldous Huxley since it had been called "beautiful book" by Schrodinger in his "What Is Life?". But it is not the type of writing I am fond of. It is an anthology of "Perennial Philosophy" from scripture-like sources. I just don't like it.

Excerpts from Adventures of a Mathematician

1. Like mathematics, chess is one of the things where constant practice, constant thinking, and imagining, and studying are necessary to achieve a mastery of the game.

2. It was most stimulating to watch him (Banach) work at the blackboard as he struggled and invariably managed to pull through.

3. In mathematical discussions, or in short remarks he (Banach) made on general subjects, one could feel almost at once the great power of his mind. He worked in periods of great intensity separated by stretches of apparent inactivity.

4. It is such persistence and habit of concentration which somehow becomes the most important prerequisite for doing genuinely creative mathematical work.

5. In those days I went to almost every available general talk.

6. I had an almost pathological aversion to examinations.

7. I worked for a week on the thesis, then wrote it up in one night, from about ten in the evening until four in the morning, on my father's long sheets of legal paper.

8. As for myself, ever since I started learning mathematics I would say that I have spent - regardless of any other activity - on the average two to three hours a day thinking and two to three hours reading or conversing about mathematics. Sometimes when I was twenty-three I would think about the same problem with incredible intensity for several hours without using paper or pencil.

9. I was so absorbed and almost perpetually drunk with mathematics that I was not really aware of it.

10. I already had a pronounced book-buying - or, at least, book-handling - mania.

11. The American accent took me by surprise, and I missed most of what was being said. Then after a week I understood everything. This is a common experience, not only with languages but also with mathematics - a discontinuous process. Nothing, nothing, at first, and suddenly one gets the hang of it.

12. I have often succeeded in obtaining rather original and not unimportant results in areas where I did not know the foundations or details of a theory too well.

13. As a mathematician, von Neumann was quick, brilliant, efficient, and enormously broad in scientific interests beyond mathematics itself.

14. I talked with confidence - I don't remember ever being very nervous about giving talks because I always felt I knew what I was talking about.

15. What I dislike is the obligation to be at a given place at a given time - not being able to feel completely free. This is because one of my characteristics is a special kind of impatience. When I have a fixed date, even a pleasant dinner or party, I fret. And yet when I am completely free, I may become restless, not knowing what to do.

16. In our mathematical conversations, as always, I was the optimist, and had some general, sometimes only vague ideas. He supplied the rigor, the ingenuities in the details of the proof, and the final constructions.

17. Six or seven years younger that I, he (Feynman) was brilliant, witty, eccentric, and original.

18. Fermi was overwhelmingly rational. Let me explain what I mean: the special theory of relativity was strange, irrational, seen against the background of what was known before. There was no simple way to develop it through analogies with previous ideas. Fermi probably would not have tried to develop such a revolution.

19. What people think of as inspiration or illumination is really the result of much subconscious work and association through channels in the brain of which one is not aware at all.

20. "Mathematics is a language in which one cannot express unprecise or nebulous thoughts," said Poincare.

What is Life?

It is the little book by the renowned physicist, Erwin Schrodinger, from 1944 that inspired a batch of molecular biologists and other scientists (including James Watson, Francis Crick, Maurice Wilkins, and Roger Penrose) in their early life. That the hereditary substance is a molecule has been described with conviction in the book. Many of the concepts are dated. I liked the chapter, "Order, Disorder, and Entropy." As far as I understand, he believed that life and the idea of "I" (consciousness) are manifestations of physical processes, which has been my notion as well.

Sensor API for Symbian OS

• It appears that in order to access accelerometer data, Sensor API must be used. Sensor API is available in S60 5th Edition SDK (Nokia N97). Nokia N96 has S60 3rd Edition SDK FP2, so the Sensor API plugin must be installed.
• Here is a cool template plugin for sensor specific projects in Carbide.C++
• Here is an excellent explanation of the features in Sensor API

Hello World, Console Application

1. The International Mobile Equipment Identity or IMEI number is needed for using SymbianSigned online service. Type *#06# on the phone and the number will be shown.
2. Check your phone's date and time, adjust it if needed.
3. Append "FR, RI" (File Run, Run on Installation) in the pkg file after exe-file's path

Seed Idea

I believe that one must have some seed idea upon which to build considerable amount of work and produce something concrete at the end. I should stick to my first and only idea, ePet and build upon it whatever is needed in the best possible way to deliver its potentials. For example what can be the mathematical formulation of the idea and what are the practical limitations, can be a line of research. For a start, I should build a working application of ePet in Symbian C++ and test performance based on various criteria.

Confession

During my undergrad, I had been (foolishly) caught up with my adolescent love, the idea of studying Physics. The idea that somehow at the end I will be studying String Theory never left my mind. I started studying things in Computer Science at a very late stage and failed to pull up much by the end. I thought it would be better to work in a software farm to learn something about coding in big projects which I severely lacked by then. I guess that was not a bad idea. I always looked at PhD as a period during which I could be as creative as I wish. Yet thinking about the gaps and delays along my way, I was not at all initiated to pursue a PhD. I was thinking about doing some other kind of creative work, e.g., writing seriously or even working for a theatre. Meanwhile, I registered and appeared for GRE and TOEFL almost out of whim of the vogue. And in between GRE and TOEFL, I approached an offer for PhD, without giving much thoughts to what actually I would be doing. In retrospect, I made many thoughtless decisions. I don't want to get a PhD as a respected degree only, I want to completely lose myself in something great. For now, I don't see much future to that end, so I have decided to stop here.

Something About Logic

1. Invalid solutions to quadratic equations: I remember, we had to solve some maths in Chemistry which usually yielded two solutions, one of them would be absurd. I always wondered why one of the mathematically derived solutions should be absurd in reality. One reasoning could be, the mathematical modeling of the reaction scenario is more general than what was needed; so, not all solutions are applicable for the Chemistry scenario. What about those quadratic equations where if you put one of the solutions in, the mathematical equation is not satisfied! It can be understood through logic. Both of the solutions to the quadratic equation are valid only when every next step in the solution-procedure is an 'if and only if' or bi-directional implication. For example, x + 2 = sqrt(4 -x) has an absurd solution where x = -5. Putting x = -5 in the left hand side of the equation gives -3 whereas in the right hand side gives 3. For when we square the equation on both sides, we have a unidirectional implication or the 'if' part only: x+2 = sqrt(4-x) implies (x+2)^2 = 4-x, but not the other way around.
2. Deductive vs. Inductive Reasoning: Deductive Reasoning is based on premises and logically arrived upon conclusions, whereas Inductive Reasoning is based on examples studied so far: 'I have seen this event in 1000 cases and I say it will also happen in the 1001th case.' Mathematicians do not consider Inductive Reasoning as a form of proof in contrast to experimental scientists who are usually reasonably (due to practical limitations) satisfied with Inductive Reasoning backed up by some number of experiments. Yet we should always keep in mind that there is no categorical reason to expect that the 1001th case will be similar.

Reading List: Game Theory and Bounded Rationality

Game Theory:

1. A Course in Game Theory. Martin J. Osborne and Ariel Rubinstein
2. Game Theory. Drew Fudenberg and Jean Tirole
3. Models in Cooperative Game Theory. Rodica Branzei, Dinko Dimitrov, and Stef Tijs
4. Game Theory Evolving. Herbert Gintis
5. Algorithmic Game Theory. Noam Nisham, et al.
6. Playing for Real: A Text on Game Theory. Ken Binmore
7. Grey Game Theory and Its Applications in Economic Decision-making. Fang et al.
8. Game Theory: Analysis of Conflict. Roger B. Myerson
9. Game Theory: A Multi-level Approach. Hans Peters
10. Essentials of Game Theory. Kevin Leyton-Brown and Yoav Shoham
11. Theory of Games and Economic Behavior. Neumann and Morgenstern
12. Essays on Game Theory. John Nash
13. Multiagent Systems. Yoav Shoham and Kevin Leyton-Brown
14. Thinking Strategically. Avinash K. Dixit and Barry J. Nalebuff
15. Strategies and Games. Prajit K. Dutta
16. Strategy. Joel Watson
17. On Numbers and Games. John Conway
18. Winning Ways for Your Mathematical Plays. Erwin Berlekamp et al.
19. Incomplete Information, Repeated Games, and N-Player Games. Evelyn C. Fink et al.
20. Repeated Games with Incomplete Information. Aumann and Maschler
21. A First Course on Zero-Sum Repeated Games. Sorin
22. Repeated Games and Reputations. Mailath and Samuelson
23. Readings in Games and Information. Rasmusen
    

Bounded Rationality:

1. Modeling Bounded Rationality. Ariel Rubinstein
2. Rationality, Bounded Rationality and Microfoundations. Reza Salehnejad
3. Economics, Bounded Rationality and the Cognitive Revolution. Herbert Simon et al.

Microeconomics:

1. Auction Theory. Vijay Krishna
2. A Mathematical Approach to Economic Analysis. Peter Toumanoff and Farrokh Nourzad
3. Essential Mathematics for Economic Analysis. Knut Sydsater and Peter Hammond
4. Lecture Notes in Microeconomic Theory: The Economic Agent. Ariel Rubinstein

Greatest Evil

Inconsistency: switching between topics at the surface-level. The reason is fear, fear of losing even what might have been easy to achieve. Be pragmatic and be imaginative at the same time. One line is for career and the other is for the soul, for dreaming.

1. Stick to Game Theory as the creative line.

2. Stick to Usable Security, Location Privacy, and People-centric Sensing as the paper-generating lines.

3. Learn mobile phone programming as much as possible by doing projects.

1a. Learn Microeconomic Theory

2a. Read papers, generate ideas, imagine, and think, collaborate

3a. Meet every deadline cleanly for the Breast Cancer Project.

Lectures on Game Thery

• Links to Lecture Notes
• Polak's video lectures
  

Concave and Quasi-concave Functions

• A mathy introduction by Wilson
• Quasiconcavity and Quasiconvexity by Osborne

Textbooks...

I bought Playing For Real, a book on Game Theory by Ken Binmore. It was too wordy for me as a beginner and I became restless after a while, and the extensive use of Philosophical, Economic, and Card Games (I don't know Card Games) examples exacerbated my frustration. I found some suggested readings by Kevin Leyton-Brown in his website, he is the co-author of Essentials of Game Theory (EoGT). I started reading EoGT, but it was too concise for me. According to Kevin's suggestion (from his website), I have started reading, A Course in Game Theory by Martin J. Osborne and Ariel Rubinstein, today.

The beginning...

I was searching for some topic to pursue as a researcher. I had always been interested in consmogeny, abiogenesis, consciousness, and epsitemology. Each one is fundamental as well as big idea. Having been thrown into the realm of small devices, I started thinking, if the small device needs an entirely new from of intelligence. I came across the idea of Swarm Intelligence, which deals with the emergence of intelligent behavior out of simple actions and interactions among a huge number of almost dumb agents, e.g., a colony of ants (in contrast to Chaos Theory which investigates how simple initial rules can result in chaotic behavior). Small devices can be made smarter so that they are not so dumb as to work exclusively under the rubric of Swarm Intelligence. At the same time, they are resource-constrained in comparison to computers. Intelligent behavior calls for decision-making which leads us to Game Theory. Game Theory assumes that agents are rational and think strategically (in the shoes of others). Traditional Game Theory takes for granted that all agents in a game are equally rational, but in real life that is not the case most of the times. Also, in the digital world, there are diverse devices with different levels of analytical abilities due to resource-limitations which take part in games with one another. How to incorporate asymmetric rationality in agents in games? There is the Bounded Rationality, started by Herbert Simon which puts forth the idea of limitedly rational agents under resource-constraints. There have been some works in injecting limits or asymmetry in the agents' rationality in games. My motivation for openning this blog is to record my thoughts as I explore, learn, and discover ideas related to Game Theory in general, and in particular, Games played by agents with limited or asymmetric rationality. My plan is to see how I go along over a period of one year (till 6 July 2011).