Scientiest found The Edge of Space

Canadian technology on NASA mission is a prototype for future, longer mission

Where does space begin? Scientists at the University of Calgary have created a new instrument that is able to track the transition between the relatively gentle winds of Earth's atmosphere and the more violent flows of charged particles in space—flows that can reach speeds well over 1,000 km/hr. And they have accomplished this in unprecedented detail.

Data received from the U of C-designed instrument sent to space on a NASA launch from Alaska about two years ago was able to help pinpoint the so-called edge of space: the boundary between the Earth's atmosphere and outer space.

With that data, U of C scientists confirmed that space begins 118 km above Earth and the results were published this week in the Journal of Geophysical Research.

The instrument—called the Supra-Thermal Ion Imager—was carried by the JOULE-II rocket on Jan. 19, 2007. It travelled to an altitude of about 200 km above sea level and collected data for the five minutes it was moving through the "edge of space."

The Canadian Space Agency invested $422,000 in the development of the Supra-Thermal Ion Imager instrument on JOULE-II.

The ability to gather data in that area is significant because it's very difficult to make measurements in this region, which is too high for balloons and too low for satellites.

"It's only the second time that direct measurements of charged particle flows have been made in this region, and the first time all the ingredients—such as the upper atmospheric winds—have been included," says David Knudsen, associate professor in the Department of Physics and Astronomy at the University of Calgary.

Knudsen and his former PhD student Laureline Sangalli are the lead authors of the paper. Co-authors include: JOULE-II lead scientist Miguel Larsen of Clemson University, Robert Pfaff and Douglas Rowland of NASA Goddard Space Flight Center and T. Zhan of Conseco Inc.

"When you drag a heavy object over a surface, the interface becomes hot. In JOULE-II we were able to measure directly two regions being dragged past each other, one being the ionosphere—being driven by flows in space—and the other the earth's atmosphere," says Knudsen, who also is the head of the Space Physics Division of the Institute for Space Imaging Sciences (ISIS). The institute is a research partnership between the University of Calgary and University of Lethbridge.

The measurements confirmed what other scientists consider the boundary or edge of space.

"The results have given us a closer look at space, which is a benefit to pure research in space science," Knudsen says. "But it also allows us to calculate energy flows into the Earth's atmosphere that ultimately may be able to help us understand the interaction between space and our environment. That could mean a greater understanding of the link between sunspots and the warming and cooling of the Earth's climate as well as how space weather impacts satellites, communications, navigation, and power systems."

The U of C-designed instrument has been adopted by COM DEV, an Ontario-based global designer and manufacturer of space hardware, and is being used as a prototype for three instruments currently being readied to fly on the European Space Agency's "Swarm" satellite mission, set to launch late next year and to collect data for four years. The JOULE-II instrument is one in a long list of more than a dozen instruments designed by U of C scientists in the past forty years which have flown in space. There are at least five more being readied to go on missions in the next two years.

"Understanding the boundary between the Earth's atmosphere and outer space is fundamental to the bigger picture of the effects of space on the Earth's climate and environment," says Russ Taylor, the director of ISIS and head of the Department of Physics and Astronomy at the U of C. "This detection is part of a long history of success by ISIS researchers in designing and building innovative instruments flown on rockets and satellites to image the flow of matter and energy between the Earth and Space."

The paper "Rocket-based measurements of ion velocity, neutral wind, and electric field in the collisional transition region of the auroral ionosphere" was published this week in the Journal of Geophysical Research.

Move over, Newton: Scientifically ignorant computer derives natural laws from raw data

By Bill Steele

If Isaac Newton had had access to a supercomputer, he'd have had it watch apples fall and let it figure out what that meant. But the computer would have needed to run an algorithm developed by Cornell researchers that can derive natural laws from observed data.

Lindsay France/Cornell University Photography

Professor Hod Lipson and graduate student Michael Schmidt adjust a double pendulum. Refectors on the pendulum enable motion-tracking software to record position and velocity as the pendulum swings. From this a new computer algorithm can derive equations of motion.

The researchers have taught a computer to find regularities in the natural world that represent natural laws -- without any prior scientific knowledge on the part of the computer. They have tested their method, or algorithm, on simple mechanical systems and believe it could be applied to more complex systems ranging from biology to cosmology and be useful in analyzing the mountains of data generated by modern experiments that use electronic data collection.

The research is described in the April 3 issue of the journal Science (Vol. 323, No. 5924) by Hod Lipson, associate professor of mechanical and aerospace engineering, and graduate student Michael Schmidt, a specialist in computational biology.

Their process begins by taking the derivatives of every variable observed with respect to every other -- a mathematical way of measuring how one quantity changes as another changes. Then the computer creates equations at random using various constants and variables from the data. It tests these against the known derivatives, keeps the equations that come closest to predicting correctly, modifies them at random and tests again, repeating until it literally evolves a set of equations that accurately describe the behavior of the real system.

Technically, the computer does not output equations, but finds "invariants" -- mathematical expressions that remain true all the time, from which human insights can derive equations.

"Even though it looks like it's changing erratically, there is always something deeper there that is always constant," Lipson explained. "That's the hint to the underlying physics. You want something that doesn't change, but the relationship between the variables in it changes in a way that's similar to [what we see in] the real system."

Once the invariants are found, potentially all equations describing the system are available: "All equations regarding a system must fit into and satisfy the invariants," Schmidt said. "But of course we still need a human interpreter to take this step."

The researchers tested the method with apparatus used in freshman physics courses: a spring-loaded linear oscillator, a single pendulum and a double pendulum. Given data on position and velocity over time, the computer found energy laws, and for the pendulum, the law of conservation of momentum. Given acceleration, it produced Newton's second law of motion.

The researchers point out that the computer evolves these laws without any prior knowledge of physics, kinematics or geometry. But evolution takes time. On a parallel computer with 32 processors, simple linear motion could be analyzed in a few minutes, but the complex double pendulum required 30 to 40 hours of computation. The researchers found that seeding the complex pendulum problem with terms from equations for the simple pendulum cut processing time to seven or eight hours. This "bootstrapping," they said, is similar to the way human scientists build on previous work.

Computers will not make scientists obsolete, the researchers conclude. Rather, they said, the computer can take over the grunt work, helping scientists focus quickly on the interesting phenomena and interpret their meaning.

The research was supported by the National Science Foundation.

Fix Yast2 unable to install package

Look in /var/run/ for stale yast.pid or zypp.pid and delete them.

To Find a Square-root with miniMIPS

###############################################################################
# To find a square-root of an integer
# (c) M. Lutfi, 2009
#
# Platform: miniMIPS
# tested on: MARS simulator
#
# Convention:
# $v0..$v1,$t0..$t9,$a0: destroyed during procedure calls
# $s0..$s9: saved during procedure calls
###############################################################################

.text
main:
la $a0, question
jal print_string # print(question)
addi $v0,$zero,5
syscall # read integer. v0 contains the integer read (x)
add $s0,$v0,$zero # s0 = x
bltu $s0,$zero,error # exit if x <>
beqz $s0,just_print # print "0" if x == 0
beq $s0,1,just_print # print "1" if x=1

addi $t1,$zero,0 # a = 0
add $t2,$s0,$zero # b = x

loop:
add $t3,$t1,$t2 # t3 = (a+b)
sra $t3,$t3,1 # mid = (a+b)/2
beq $t3,$t1,print_sqrt
beq $t3,$t2,print_sqrt # to prevent endless loop and give approx. result
multu $t3,$t3 #(hi,lo) = mid*mid
mflo $t4
mfhi $t5 # (t5,t4) = mid^2
beq $t4,$s0,print_sqrt # if (mid^2 == x) goto print_sqrt
bgtu $t4,$s0,set_b # if (mid^2 > x) goto set_b
bltu $t4,$s0,set_a # if (mid^2 <>

set_a:
add $t1,$t3,$zero # a = mid
j loop

set_b:
add $t2,$t3,$zero # b = mid
j loop

print_sqrt:
la $a0,answer
jal print_string # print "sqrt(x) = "
add $a0,$t3,$zero # mid is the sqrt(x)
jal print_integer # print the result
j main # do it again. To finish, just enter neg number
j exit

error:
la $a0, inv_num
addi $v0,$zero,4
syscall
j exit

just_print:
la $a0,answer
jal print_string # print "sqrt(x) = "
add $a0,$s0,$zero #print_integer(x)
jal print_integer

exit: # no param needed
addi $v0,$zero,10
syscall # exit


#---------------------------------subroutines----------------------------------
print_string: # string address in a0
addi $v0,$zero,4 # a0 and v0 are destroyed
syscall
jr $ra

print_integer: # integer value in a0
addi $v0,$zero,1
syscall
jr $ra



#-------------------data section-----------------

.data

question: .asciiz "\nEnter number to be square-rooted: "
inv_num: .asciiz "\nInvalid number (e.g, negative"
answer: .asciiz "Sqrt(x) = "

LED Blink on PICKit2 Demoboard

The following code will make LED 1 on PICKit2 demoboard (attached to PICKit2 programmer) to blink for about every 500 mSec. Tools needed are: gputils and sdcc (all of them are open sources), and pk2cmd freely available at Microchip website.

Source code:

__sfr __at (0x2007)  CONFIG = _INTRC_OSC_NOCLKOUT & _WDT_OFF & _PWRTE_OFF & _MCLRE_OFF &
   _CP_OFF & _IESO_OFF & _FCMEN_OFF & _BOR_OFF;



unsigned char delay1val;
unsigned char delay2val;

void delay()
{
    __asm
    CLRF        _delay1val
    CLRF        _delay2val
    loop:
    DECFSZ      _delay1val,f
    GOTO        loop
    DECFSZ      _delay2val,f
    GOTO        loop
    __endasm;
}

void main()
{
    // make C0 as output
    TRISC0 = 0;
    do {
       RC0 = 1;
       delay();
       RC0 = 0;
       delay();
    } while (1);
}

Makefile:

OBJS=demo1.o
PRJ=demo1
CHIP=690
ARCH=pic14
PLATFORM=16f$(CHIP)
LIBPATH=-I/usr/local/share/gputils/lkr -I/usr/local/share/sdcc/lib/pic
LINKSCRIPTPATH=/usr/local/share/gputils/lkr
LIBS=libsdcc.lib pic$(PLATFORM).lib libm.lib
CC=sdcc -V -m$(ARCH) -p$(PLATFORM)
LINKER=/usr/local/bin/gplink
CFLAGS=--opt-code-speed --stack-auto --main-return --profile --debug-xtra --no-pcode-opt --funsigned-char --Werror
CPPFLAGS=

.c.o:
  $(CC) $(CFLAGS) -D_16F$(CHIP) -c $<

$(PRJ).hex: $(OBJS)
        $(LINKER) -w -O1 -m -o $(PRJ).hex $(OBJS) $(LIBPATH) -f 0 $(LIBS) -s $(LINKSCRIPTPATH)/$(PLATFORM).lkr
   all: $(PRJ).hex
   clean:
        @echo "cleaning up all generated files..."
        @for obj in $(OBJS); do \             if [ -e $$obj ] ; then rm $$obj ; fi \         done
        @rm *.lst
        @if [ -e $(PRJ).cod ] ; then rm $(PRJ).cod ; fi
        @if [ -e $(PRJ).hex ] ; then rm $(PRJ).hex ; fi
        @echo "done."
install:
        pk2cmd -PPIC$(PLATFORM) -M -F$(PRJ).hex
        pk2cmd -PPIC$(PLATFORM) -T

To build:
make demo1.hex

To install:
make install

PICKIT2 on OpenSUSE

First, create a new udev rules under /etc/udev/rules.d/, name it as "26-microchip.rules".
Add the following into the file:

# PicKit2
SUBSYSTEM=="usb_device", ACTION=="add", SYSFS{idVendor}=="04d8", SYSFS{idProduct}=="0033"
MODE="660", GROUP="microchip", RUN="/usr/local/bin/pk2cmd I /PPIC16F690", SYMLINK+="pickit2"

(do lsusb to verify the vendor and produc id)

Then, execute this on the shell:

sudo udevadm control --reload_rules

Then, download pk2cmd (search google. It should be linked to Microchip website. or try this: http://ww1.microchip.com/downloads/en/DeviceDoc/pk2cmdv1.20LinuxMacSource.tar.gz), compile and install.

When everything is complete with no error, plug in the PICkit2 USB to PC. Check that a new symbolic link was created under /dev as: pickit2. If it is there, you are good to go. Fire up the pk2cmd.

For example, assume the demo code has been there in the demo board and we just want to turn it on, we just need to type: pk2cmd -T /PPIC16F690. To get to know the attached chip on the demo board, try: pk2cmd -I -PPIC16F690

For example:
#> pk2cmd -I -PPIC16F690

Device ID = 1400
Revision = 0005
Device Name = PIC16F690

Operation Succeeded