computer-science

Why do we need different CPU architecture for server & mini/mainframe & mixed-core?

Hello, I was just wondering what other CPU architectures are available other than INTEL & AMD. So, found List of CPU architectures on Wikipedia. It categorizes notable CPU architectures into following categories. Embedded CPU architectures Microcomputer CPU architectures Workstation/Server CPU architectures Mini/Mainframe CPU archite...

merge sort recursion tree height

Hello! I am learning about recursion tree's and trying to figure out how the height of the tree is log b of n where n = 2 and one has 10 elements as input size. I am working with Merge sort. The number of times the split is done is the height of the tree as far as I understood, and the number of levels in the tree is height + 1. But ...

P implies Q, how to read in english

how to read P implies Q in classical logic? example : Distributivity: Ka(X->Y) -> (KaX -> KaY) This is modal logic which uses classical logic rules. KaX : a knows the that X is true. I m curious about how to read implication in english? if then else? Edit : in Modal Logic, Ka becomes Box, well it s boxed shape sign, that symb...

Approximate timings for various operations on a "typical desktop PC" anno 2010

In the article "Teach Yourself Programming in Ten Years" Peter Norvig (Director of Research, Google) gives the following approximate timings for various operations on a typical 1GHz PC back in 2001: execute single instruction = 1 nanosec = (1/1,000,000,000) sec fetch word from L1 cache memory = 2 nanosec fetch word from main memory = 1...

Which operating systems book should I go for?

Hi, I'm in a confusion. For our course (1 year ago) I used Stallings. I read it. It was fine. But I don't own any operating system's book. I want to buy a book on operating systems. I'm confused!! which one to pick? Modern Operating Systems (3rd Edition) ~ Andrew S. Tanenbaum (Author) Operating System Concepts ~ Abraham Silberschatz , ...

Where should a beginner start with computer vision?

Hi, I'm an undergrad who finds computer vision to be fascinating. Where should somebody brand new to computer vision begin? ...

What is the best method of assessment for computer science students?

This question is a bit more philosophical so feel free to remove if you like but it's been bugging me for the last 4 years! As a final year student I find that exams can be often be passed with a couple of days of cramming, without necessarily retaining or understanding the content i.e. a regurgitation of lecture notes is often enough t...

What is the best way to implement this composite GetHashCode()

I have a simple class: public class TileName { int Zoom, X, Y; public override bool Equals (object obj) { var o = obj as TileName; return (o != null) && (o.Zoom == Zoom) && (o.X == X) && (o.Y == Y); } public override int GetHashCode () { return (Zoom + X + Y).GetHashCode(); } } I w...

How is a new programming language actually formed/created ?

Fortran->Algol->Cpl->Bcpl->C->C++->Java ..... Seems like every language is built upon an ancestor language. My question : New languages extend parent ones or there is some kind of a trick? e.g. System.out.print() in Java ; is it actually printf() in C, and so on (printf is actually .. in Cpl)? If so, doesn't this make every further l...

What areas of computer science are particularly relevant to mobile development?

This isn't a platform specific question - rather I'm interested in the general platform independent areas of computer science that are particularly relevant to mobile applications development. For example, things like compression techniques, distributed synchronisation algorithims etc.. what theoretical concepts have you found relevant,...

Mutual Information / Entropy Calculation Help

Hi, Hoping someone can give me some pointers with this entropy problem. Say X is chosen randomly from the uniform integer distribution 0-32 (inclusive). I calculate the entropy, H(X) = 32 bits, as each Xi has equal probability of occurring. Now, say the following pseudocode executes. int r = rand(0,1); // a random integer 0 or 1 r ...

What's the term for a program or system that is used to maintain itself?

And I don't mean skynet. I'm thinking of say a compiler application that is used to compile itself, a VCS that tracks its own source code etc. ...

Complex behavior generated by simple computation

Stephen Wolfram gave a fascinating talk at TED about his work with Mathematica and Wolfram Alpha. Amongst other things, he pointed out how very simple computations can yield extremely complex behaviors. (He goes on to discuss his ambition for computing the entire physical universe. Say what you will, you gotta give the guy some credit fo...

recursion tree and binary tree cost calculation

Hi all, I've got the following recursion: T(n) = T(n/3) + T(2n/3) + O(n) The height of the tree would be log3/2 of 2. Now the recursion tree for this recurrence is not a complete binary tree. It has missing nodes lower down. This makes sense to me, however I don't understand how the following small omega notation relates to the co...

Master theorem: Why the constant?

In the Master Theorem, cases 1 & 3 you have if f(n) = O(log b of a-e) in case 1, I wondered why one has to subtract the constant e there? In the third case of the master theorem one has to add a constant... Why is that so? What is the constant based on? ...

Turing Model Vs Von Neuman model

First some background (based on my understanding).. The Von-Neumann architecture describes the stored-program computer where instructions and data are stored in memory and the machine works by changing it's internal state, i.e an instruction operates on some data and modifies the data. So inherently, there is state maintained in the sys...

A Question About the Expressive Power of Higher-Order Logical Reasoning Formalisms.

Hi! I do not really know if this is scientifically proven, but I've read in a book (It was a relatively modern AI book by Peter Norvig) that second-order logical programming could be more expressive than existing first-order languages. The question is: Is it statistically/symbolically proven that higher-order predicate logics exceed fi...

What makes people think that NNs have more computational power than existing models?

I've read in Wikipedia that neural-network functions defined on a field of arbitrary real/rational numbers (along with algorithmic schemas, and the speculative `transrecursive' models) have more computational power than the computers we use today. Of course it was a page of russian wikipedia (ru.wikipedia.org) and that may be not properl...

What is the most easy way to get in advanced Type Theory.

Of course, by 'advanced' I mean here just something beyond what every programmer does know. I'm currently more-or-less comfortable with the basics and want to understand the most important, most elegant and most practically applicable achievements of modern type theory. I just do not have much time, desire and mental powers to study all...

What tools & media are available out there that helps me in understanding statistics in better way?

Hello, I'm a graduate student very much interested in Machine Learning, Pattern Recognition & Artificial Intelligence. These subjects are just applications of great mathematical subject Statistics. As an undergraduate, I've done courses in Probability and Statistics. We've used it in many other subjects. But sadly its still is very abs...