How can root forcefully logout a user in linux?

Use the who command to see list of logged in users and
sudo pkill -KILL -u username
to log out use

geant4 installation on Linux

I got so many troubles in trying install Geant4 on Linux (Ubuntu, CentOs, Federo....). Everytime I got Geant4 initial installation errors.

Now no any error by install the following packages before Geant4:
•libX11-dev
•g++
•libxft-dev
•libxpm-dev
•libxt-dev
•freeglut3
•freeglut3-dev
•libglut3
•libglut3-dev
•libmotif3
•libmotif-dev
•x11proto-print-dev
•libxaw7-dev
•libmudflap0
•libmudflap0-dev
•po-debconf
•intltool-debian
•subversion
•libusb-dev
•libboost-dev
•libmysql++-dev
•autoconf
•automake
•libtool
• libc6-dev-i386
•graphviz and graphviz-dev for GraphViz software
•libcxx
•libxerces28
•libxerces28-dev
•cppunit-dev

this list is from http://www.scribd.com/doc/17465713/Set-Up-Root-and-Geant4-On-Ubuntu
byJessica Chiang

GA-EP43-UD3L for os x sound and graphic card notes

using Iantares 10.6.3 version, installation was very smooth without any heck up. Everything works bu no sound and no graphic support other than 1024 by 768.

1. using this method to make sound works, downloaded acl1062.zip and followed the instruction.

2. using nvenabler.kext 64 bit, after restart, works like a charm!

the kext installation helper software makes everything easy.

update1: if 2 does not work, try this methods .

next step was to install retail version with bootloader.

update2: tried lots methods for the retail, no luck, give up.

Update 3 on Sept 20 2011:
get the Lion installed very easily, after installation, no sound and graphic not ready. Use the above methods to fix both.Wonderful!

recover windos xp administrator password

if you forget the password, one way (time consuming but worked for me) is to use xp install cd. boot from the CD, on the first window choose install (don't choose repair at this point), then on the second window ask you install, repair or exit, choose repair by press R, then wait the system copy lots files . the system will restart, when the windows start install driver, press"shift+F10" at the same time, this will give you a command window. Now you can type "Lusrmgr.msc" and the local user and group management pop up. Now you can change, reset, and delete any account's password.
close local user management window and the command window, let windows repair process go through.

Fast kilovoltage/megavoltage (kVMV) breathhold cone-beam CT for image-guided radiotherapy of lung cancer

Fast kilovoltage/megavoltage (kVMV) breathhold cone-beam CT for image-guided radiotherapy of lung cancer: "- Sent using Google Toolbar"

MTF CURVE ?

Fig. 1 : object	Fig 2 : image

An optical instrument aims at a pattern composed of alternatively dark and bright bars (figure 1) whose spacing is adjustable. At the focus of the instrument, the image of the pattern is found again (figure 2), but the edges of the bars are less sharp and the contrast is weak : blacks became dark grey, whites became light grey.

The ratio of the contrast of the image (C_i) to the contrast of the pattern (C_p) is a excellent indication of the quality of retransmission of information by the instrument. Ideally, this ratio would be 1 : image identical to object. Un fortunately, the laws of diffraction tell us that at the focus of an instrument, the image of a light point is not a point but a figure whose size is not infinitely small. This means that even a perfect instrument is incapable of retransmitting the information with an absolute accuracy. The ratio C_i/C_p is always less than 1.

The curve above represents the value of the contrast ratio according to the spacing of the pattern bars, for a perfect instrument with no obstruction. When the spacing is very large (small spatial frequency), the instrument retransmits the information with a good accuracy : the ratio is close to 1 (left end of the curve). Then, when the spacing decreases (the spatial frequency increases), the contrast decreases (central part of the curve). Finally, when the bars are very thin (high spatial frequency), the instrument is incapable of separating them : the image is uniformly grey, without any detail (right end of the curve). The resolution limit of the instrument is attained. This maximum frequency only depends on the light wavelenght (l) and the diameter of the instrument (D), its value is (in lines pairs per radian) :

F_max = D/l

For a 250 mm telescope, at 0.6 µm this limit corresponds to 2 lines pairs per arc second, ie 1 line (dark or bright) for 1/4 of arc second.

This limit frequency increases if the wavelenght decreases or if the diameter of the instrument increases. The following figure represents the MTF (Modulation Transfer Function) curves for two perfect instruments when the diameter of one of them is half of the diameter of the other. The largest telescope is able to show thinner details, its theoretical limit of resolution is twice the limit of the small instrument.

Although astronomical objects do not look like bar patterns, this type of curve gives valuable information about the performances of an instrument on celestrial objects like the planets or the Moon, because it indicates how the telescope retransmits the contrasts. The scanning of the different spatial frequencies allows to observe the behaviour of the telescope on details at different scales, the low frequencies corresponding to the large details and the high frequencies corresponding to the small details. Moreover, this type of representation allows to display the consequences of all kinds of aberrations that can affect the instrument, and even to simulate their effects on real images.

directly from:http://astrosurf.com/legault/mtf.html

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in Mac OS X, how do I connect to and share files with a Windows computer or vice versa?

copied from Indiana University website

In Mac OS X, how do I connect to and share files with a Windows computer?

In Mac OS X 10.1.x and higher, before you can connect and share files with a Windows computer within your network, you must first create a share folder on the Windows computer. You must also have a local account on that computer. Then follow the appropriate directions below.

Creating a Windows share folder

1. In Windows, create a new folder or select an existing one. Right-click the folder, and from the contextual menu, select Properties.
   
   
2. Select the Sharing tab, and check the box next to Share this folder or Share this folder on the network.
   
   
3. In the "Share name:" field, provide a name for the share and click OK. A one-word name is simpler and reduces the risk of confusion.

Connecting to a Windows computer on the network

Beginning in Mac OS X 10.2 and continuing with later releases of OS X, you can browse to a Windows computer on your network:

1. With the Finder active, from the Go menu, select Connect to Server... .
   
   
2. In OS X 10.3.x and later, in the Connect to Server window, click the Browse button. In the window that opens, you will see a listing of all the available computers (both Macintosh and Windows) on your local network.

   In OS X 10.2.x, in the Connect to Server window, if you do not already see a listing of all the available computers on the local network, click the blue triangle next to the "At:" pull-down menu.

3. Browse to and select the computer to which you wish to connect, and double-click its icon or click the Connect button.
   
   
4. Enter the workgroup name as well as your username and password for access to the computer. If you do not know the workgroup name, the default will usually work.

   Note: You must have a local account on the Windows computer you're attempting to access.

5. From the pull-down menu, select the share you wish to access and then click OK.

In OS X 10.1.x and later, you can simply enter the IP address and share name to connect to a Windows computer:

1. With the Finder active, from the Go menu, select Connect to Server... .
   
   
2. In the "Address:" or "Server Address:" field, type smb:// , then the IP address of the Windows computer to which you wish to connect, followed by a forward slash and then the share name, for example: smb://129.79.1.1/share
3. Click Connect. When prompted, supply the workgroup name as well as your Windows local account username and password. If you do not know the workgroup name, the default will usually work.

   Note: You must have a local account on the Windows computer you're attempting to access.

4. Click OK, and the shared folder will appear as a network drive mounted on your OS X computer.

Adding your OS X computer to the Windows workgroup

Optionally, you can add your OS X computer to the Windows workgroup to make it easier to browse directly to the computer:

1. Open Directory Access, which is located in /Applications/Utilities.
   
   
2. If the padlock in the lower-left corner is locked, click it to unlock it, and supply your OS X account password.
   
   
3. Make sure SMB or SMB/CIFS is checked, highlight that option, and then click the Configure... button.
   
   
4. In the "Workgroup:" field, enter the name of your Windows workgroup and then click OK.

Sharing files with a Windows computer

To access your OS X 10.2.x and later computer from Windows, you must turn on Windows sharing and then connect from the Windows computer.

Turning on Windows sharing in OS X

1. From the Apple menu, select System Preferences... .
   
   
2. In System Preferences, from the View menu, select Sharing.
   
   
3. On the Services tab, check the box next to Windows File Sharing or Windows Sharing to permit access to your OS X computer from a Windows computer.

   Note: Any Windows user attempting to access your OS X computer must have an account on your computer and must provide the username and password for that account in order to receive access.

In OS X 10.2.x, you must also complete these steps:

1. In System Preferences, from the View menu, select Accounts.
   
   
2. Select the user account to which you wish to grant Windows access, and click Edit User... .
   
   
3. Check the box next to Allow user to log in from Windows, and click OK.

Accessing your OS X computer from Windows

Note: You must have an OS X user account in order to access the OS X computer this way.

1. From the Start menu, select Run... .
   
   
2. In the "Open:" field, enter the following, replacing the IP address with that of the OS X computer to which you wish to connect and shortname with the short name for the OS X user account: \\129.79.1.1\shortname
3. In the authentication window, enter your OS X user account short name and password.
   
   
4. If you wish, you can now map this share as you would any other Windows share so that it is accessible from a drive letter. For more information, see In Microsoft Windows, how do I map a drive?