New research by a team of Univ. of Toronto scientists could lead to substantial advancements in the performance of a variety of electronic devices including digital cameras.
Researchers created a light sensor—like a pixel in a digital camera—that benefits from a phenomenon known as multi-exciton generation (MEG). Until now, no group had collected an electrical current from a device that takes advantage of MEG.
"Digital cameras are now universal, but they suffer from a major limitation: they take poor pictures under dim light. One reason for this is that the image sensor chips inside cameras collect, at most, one electron's worth of current for every photon (particle of light) that strikes the pixel," says Ted Sargent, professor in U of T's Department of Electrical and Computer Engineering. "Instead generating multiple excitons per photon could ultimately lead to better low-light pictures."
In solar cells and digital cameras, particles of light—known as photons—are absorbed in a semiconductor, such a silicon, and generate excited electrons, known as excitons. The semiconductor chip then measures a current that flows as a result. Normally, each photon is converted into at most one exciton. This lowers the efficiency of solar cells and it limits the sensitivity of digital cameras. When a scene is dimly lit, small portable cameras like those in laptops suffer from noise and grainy images as a result of the small number excitons.
"Multi-exciton generation breaks the conventional rules that bind traditional semiconductor devices," says Sargent. "This finding shows that it's more than a fascinating concept: the tangible benefits of multiple excitons can be seen in a light sensor's measured current."
SOURCE: Univ. of Toronto
Friday, June 19, 2009
Monday, June 8, 2009
Saturday, June 6, 2009
TrendNet Wifi on Beagleboard running Angstrom Linux
By default after every boot-up, Angstrom runs wpa_supplicant daemon which tries to use WPA instead of WEP regardless of configuration in /etc/network/interfaces, hence prevent us to use WEP as wifi encryption. We need to kill this daemon by executing:
root@beagleboard:~# start-stop-daemon -K -n wpa_supplicant
root@beagleboard:~# ps -ef | /bin/grep wpa*
Then reconfigure the wlan:
iwconfig wlan0
iwconfig wlan0 key
Try to see if the USB Wifi adapter gets our AP's MAC address:
root@beagleboard:~# ps -ef | /bin/grep wpa*
Finally:
ifdown wlan0
ifup wlan0
It should get the IP (assuming our AP router is running DHCP service as well):
root@beagleboard:~# route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.1.0 * 255.255.255.0 U 0 0 0 wlan0
192.168.0.0 * 255.255.255.0 U 0 0 0 usb0
default 192.168.1.1 0.0.0.0 UG 0 0 0 wlan0
default 192.168.0.200 0.0.0.0 UG 0 0 0 usb0
root@beagleboard:~#
(Note: the system used above was running Linux kernel 2.6.29:
root@beagleboard:~# uname -a
Linux beagleboard 2.6.29-omap1 #1 Wed Jun 3 18:10:47 PDT 2009 armv7l unknown
)
root@beagleboard:~# start-stop-daemon -K -n wpa_supplicant
root@beagleboard:~# ps -ef | /bin/grep wpa*
Then reconfigure the wlan:
iwconfig wlan0
iwconfig wlan0 key
Try to see if the USB Wifi adapter gets our AP's MAC address:
root@beagleboard:~# ps -ef | /bin/grep wpa*
Finally:
ifdown wlan0
ifup wlan0
It should get the IP (assuming our AP router is running DHCP service as well):
root@beagleboard:~# route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.1.0 * 255.255.255.0 U 0 0 0 wlan0
192.168.0.0 * 255.255.255.0 U 0 0 0 usb0
default 192.168.1.1 0.0.0.0 UG 0 0 0 wlan0
default 192.168.0.200 0.0.0.0 UG 0 0 0 usb0
root@beagleboard:~#
(Note: the system used above was running Linux kernel 2.6.29:
root@beagleboard:~# uname -a
Linux beagleboard 2.6.29-omap1 #1 Wed Jun 3 18:10:47 PDT 2009 armv7l unknown
)
Monday, June 1, 2009
What is the best mobile Operating system?
Duh....smartphone environment is getting more crowded with more and more new operating systems. From Microsoft Windows Mobile, Blackberry O/S, Symbian, iPhone's OS, Google's Android and now Palm's WebOS.
Which one is the best from the following criterias?
Which one is the best from the following criterias?
- UI experiences (reponsiveness, easy to use, intuitiveness, beauty look)
- Features (view rotation, touch responses, supports to various wireless tech)
- Multi-tasking
- Development environment and toolkits (including rich sets of libraries)
- Portability
- Openness (open-system, open source, proprietary)
- Price
- Hardware supports
- Availability to developers to play (at least comes with a simulator)
Wednesday, May 13, 2009
Mathematical Advances Strengthen IT Security
European Science Foundation (05/11/09) Valleley, Sofia
A new cryptography approach based on the mathematical theory of elliptic curves is considered a leading candidate to replace the widely used RSA public key security system. Elliptic curves could enable more efficient cryptography and provide an optimum combination of security and processing efficiency.
The European Science Foundation (ESF) recently held a workshop to discuss the potential for elliptic curves and other modern techniques of mathematics in cryptography and information technology security.
"The impact of the elliptic curve method for integer factorization has played a role in introducing elliptic curves to cryptographers, albeit for attacking the underlying problem on which RSA is based (the difficulty of factoring integers)," says David Kohel, convenor of the ESF workshop, from the Institut de Mathematiques de Luminy in Marseille, France. Kohel says the advantage of elliptic curve cryptography is its immunity to the specialized attacks that have degraded the strength of RSA, meaning smaller keys can be used to provide the same levels of protection.
"In general, the cryptographer has the benefit over the cryptanalyst (the person attacking the cryptosystem) as he or she can select the key size for any desired level of security, provided everyone has the same base of knowledge of best attacks on the underlying cryptosystem," he says.
A new cryptography approach based on the mathematical theory of elliptic curves is considered a leading candidate to replace the widely used RSA public key security system. Elliptic curves could enable more efficient cryptography and provide an optimum combination of security and processing efficiency.
The European Science Foundation (ESF) recently held a workshop to discuss the potential for elliptic curves and other modern techniques of mathematics in cryptography and information technology security.
"The impact of the elliptic curve method for integer factorization has played a role in introducing elliptic curves to cryptographers, albeit for attacking the underlying problem on which RSA is based (the difficulty of factoring integers)," says David Kohel, convenor of the ESF workshop, from the Institut de Mathematiques de Luminy in Marseille, France. Kohel says the advantage of elliptic curve cryptography is its immunity to the specialized attacks that have degraded the strength of RSA, meaning smaller keys can be used to provide the same levels of protection.
"In general, the cryptographer has the benefit over the cryptanalyst (the person attacking the cryptosystem) as he or she can select the key size for any desired level of security, provided everyone has the same base of knowledge of best attacks on the underlying cryptosystem," he says.
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