Search results

  1. E

    Relationships between bandwidth, Fourier trans & digital modulations

    HiHo! W. Stallings's "Wireless Communications & Networks, 2nd edition" explains the relationships between bandwidth and Fourier transformation by depicting a square wave. The square wave is approximated with a Fourier series having several sine terms. The bandwidth is then defined by the...
  2. E

    Medical The Four Temperaments: Is san-mel possible?

    Hi Ho! Referring to http://en.wikipedia.org/wiki/Four_Temperaments under "Temperament Blends", I would like to discuss whether it is possible for a person to have a blend of sanguine and melancholic at the same time. AFAIK, a sanguine tends to be sloppy while a melancholic tends to be...
  3. E

    Integration of ((e^x)/(x^2)) with respect to x

    Homework Statement \int{\frac{e^x}{x^2}dx} Homework Equations Integration by substitution Integration by parts: \int{u\ dv}=uv\ -\ \int{v\ du} The Attempt at a Solution Since it was clear that integration by substitution would not work, I tried integration by parts...
  4. E

    What is in all in a Makefile?

    What is "::" in "all::" in a Makefile? Hi Ho! Executing GNU Make: If Makefile only contains the following lines, all: echo $@ it will produce echo all all If Makefile only contains the following lines, all:: echo $@ it will still produce echo all...
  5. E

    The missing Indian Hill Guide (ftp:ftp.cs.washington.edu/pub/cstyle.tar.Z)

    Hi Ho! Could someone please help me in obtaining the latest Recommended C Style and Coding Standards (Updated Indian Hill Guide)? The file cannot be found any longer at [PLAIN]ftp://ftp.cs.washington.edu/pub/cstyle.tar.Z[/URL]. I don't know the reason why the file is missing from the...
  6. E

    The primary key of a relationship set in an E-R data model

    Hi Ho! I have posted this same question about three weeks ago on MySQL forum (http://forums.mysql.com/read.php?125,197805,197805) and on the mailing list of the book itself about two weeks ago (db-book-list@cs.yale.edu). But, still there is no response at all. Therefore, I try my luck by...
  7. E

    Why does an IP addreess need to be associated with an interface?

    Hi Ho! On page 322 of Computer Network: A Top-Down Approach Featuring the Internet, 2nd Edition by Kurose and Ross, which is published by Addison-Wesley, it is stated that: "Because every host and router is capable of sending and receiving IP datagrams, IP requires each host and router...
  8. E

    Why not multiple inclusion of a header file if certain precautions are taken?

    Hi Ho! I often heard people say that we should avoid multiple inclusion of a header file. And, they very often show how to do it. But, I myself haven't yet found the reason of not to do it when certain precautions are taken. What I am going to discuss here is C programming, not C++. I...
  9. E

    What's Wrong with My Line of Reasoning? Calculating a Hollow Sphere's Moment Inertia

    Hi Ho! I know that many books show the way to derive the moment inertia of a solid and a hollow sphere in many ways, each according to the lines of reasoning of their authors. I also have my own line of reasoning that I have successfully applied in finding the moment inertia of a solid...
  10. E

    Dy/dx: must dx be the independent variable?

    Hi Ho! If y=\sin x, \frac{dy}{dx}=\frac{d(\sin x)}{dx}=\cos x. If x=\sin y, y=\arcsin x, and therefore \frac{dy}{dx}=\frac{d(\arcsin x)}{dx}=\frac{1}{\sqrt{1-x^2}}. But, if x=\sin y, can \frac{dy}{dx} be done as \frac{dy}{dx}=\frac{dy}{d(\sin y)}=\frac{1}{\frac{d(\sin...
  11. E

    Exercising Loop: Pattern

    Hi Ho! Given an input of 5, it is easy to produce the following pattern: xxxxx xx x x x x x xx xxxxx But, given an input of 5, how would you produce the following one? 1 7 14 21 2 8 15 22 3 9 16 23 4 10 17 24 5 11 18 25 I have implemented the solution below...
  12. E

    Derivation of Euler's formula for phi(m)

    I read on http://www.cut-the-knot.org/blue/Euler.shtml that the derivation of the Euler's formula for \varphi(m) requires that the following multiplicative property of \varphi be established: \varphi(m_{1}m_{2})=\varphi(m_{1})\varphi(m_{2})\mbox{ for coprime } m_{1} \mbox{ and } m_{2} The...
  13. E

    Threads of Execution: How to Look at Them (Fast Detection of a Possible Problem)

    Hi Ho! Is there a better way of looking at more than one threads of execution besides enumerating all of the possible paths so that a person can quickly determine whether there will be a problem or not? When I face a question of determining whether two threads of execution will have a...
  14. E

    Using semaphores in a parallel programming or multi user environment

    Hi Ho! I read on http://en.wikipedia.org/wiki/Semaphore_%28programming%29 that P(Semaphore s, integer howmany) { wait until s >= 0; s := s - howmany; /* must be atomic operation */ wait until s >= 0; } Must the whole function of P be atomic or just the "s := s - howmany;"...
  15. E

    The limit of a factoring algorithm

    Hi Ho! It is easy to observe that to get all factors of an integer n, one does not need to try whether a divides n for 1 < a < n. But, rather using the following observation: Suppose n is 24, then 24 / 1 = 24 24 / 2 = 12 24 / 3 = 8 24 / 4 = 6 -------------(!) 24 / 6 = 4 24 / 8...
  16. E

    Does the implementation of system call matter for the programmer?

    Hi Ho! "To a programmer, a system call looks like any other call to a library procedure. Is it important that a programmer know which library procedures result in system calls? Under what circumstances and why?" I think it is important for a programmer to know which library procedures...
  17. E

    What kind of issues related to I/O does multiprogramming have?

    Hi Ho! When someone would like to implement a multiprogramming in a computer system, what kind of issues related to I/O does he have to consider? Is there any difference between the implementation of multiprogramming in the system that uses interrupt driven I/O and the system that uses DMA...
  18. E

    In what case will you mount a filesystem in a non-empty directory?

    Hi Ho! :smile: I just wonder in what case we want to mount a filesystem in a non-empty directory. Mounting a filesystem in a non-empty directory will cause the content of the directory to be inaccessible. So, is there any good reason to do that? Regards, Eus
  19. E

    Limit x->-infinity (x/(z^2+x^2)^0.5) = ?

    Hi Ho! :smile: Mmmm... I have a problem with this one: \lim_{x\rightarrow-\infty} \frac{x}{\sqrt{z^2+x^2}} Using a computer graphics tool, I found that the result should be -1 by looking at the generated graph. But if I do it by hands, I find 1 as follows...
  20. E

    Linear Algebra - Linear Transformation

    Hi Ho! ^_^ I stuck when doing David C. Lay's Linear Algebra in Exercise 1.8 about Linear Transformation I'm asked to determine whether these statements are correct. Statement 1: A linear transformation is a special type of function. Statement 2: The superposition principle is a physical...
  21. E

    Reading open source software code

    Hi Ho! ^^v I know that open source software can be reworked by many people. Because of that, it grows rapidly. Frankly, I wonder how people can rework it if they don't have a good technique in reading the source code. When reading Emacs source code, I really confused from where I should...
  22. E

    Crafting text editor

    Hi Ho! ^^ I'm still learning programming in C (I'm still on my first year in Information Technology faculty) Well, I'm interested in making something from scratch. Hehehe... right now I'm curious about efficient text handling technique used in a text editor. When creating a simple text...
  23. E

    Some questions about linear transformation

    Hi Ho! ^^v I've some questions regarding linear transformation in my linear algebra course, guys! Please help me! ^^v Statement: A linear transformation is a special type of function. My answer: Yes, it is a special type of function because it must satisfy the following properties from...
  24. E

    What is exactly the definition of a complete binary tree?

    Hi Ho! ^_^ Actually, what is the definition of a complete binary tree? I have searched the Internet and come up with several definition. This problem is confusing enough. According to http://planetmath.org/encyclopedia/CompleteBinaryTree.html [Broken], "A complete binary tree is a binary...
  25. E

    A system with varying mass - a rocket

    In Fundamental of Physics 6th ed. by Halliday, Resnick, Walker pg. 181-183, the section is about systems with varying mass: a rocket. It is written: Is it okay if I change M+dM with M-dM because I know that the rocket loses its mass and -dM with dM because the exhaust product has mass in...
  26. E

    A system with varying mass - two long barges

    |-------\ | Mf > -> vf |-------/ |-------\ | Ms > -> vs |-------/ Two long barges are moving in the same direction in still water, one with a speed of 10 km/h and the other with speed of 20 km/h. While they are passing each other, coal is shoveled from...
Top