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What
is Biometrics? |
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Biolmetrics refers to the automatic identification of
a person based on his/her physiological or behavioral
chara-cteristics. This method of identification preferred
over traditional methods involving passwords and PIN numbers
for various reasons:
* the person to be identified is required to be physically
present at the point-of-identification
* identification based on biometric techniques obviates
the need to remember a password or carry a token.
With the increased use of computers as vehicles of information
technology, it is necessary to restrict access to sensitive/personal
data. By replacing PINs, biometric techniques can potentially
prevent unauthorized access to or fraudulent use of ATMs,
cellular phones, smart cards, desktop PCs, workstations,
and computer networks. PI-Ns and passwords may be forgotten,
and token based methods of identification like passports
and driver's licen-ses may be forged, stolen, or lost.
Thus biometric systems of identification are enjoying
a renewed interest. Va-rious types of biometric systems
are being used for real-time identification, the most
popular are based on face recognition and fingerprint
matching. However, there are other biometric systems that
utilize iris and retinal sca-n, speech, facial thermograms,
and hand geometry.
A biometric system is essentially a pattern recognition
system which makes a personal identification by determi-ning
the authenticity of a specific physiological or behavioral
characteristic possessed by the user. An important issue
in designing a practical system is to determine how
an individual is identified. Depending on the context,
a biometric system can be either a verification (authentication)
system or an identification system. Verification (Am
I whom I claim I am?) involves confirming or denying
a person's claimed identity. In identification, one
has to est-ablish a person's identity (Who am I?). Each
one of these approaches has it's own complexities and
could proba-bly be solved best by a certain biometric
system. |
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Fingerprints |
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In recent years, fingerprints have rallied significant
support as the biometric technology that wil probably
be mo-st widely used in the future. In addition to general
security and access control applications, fingerprint
verifiers are installed at military facilities, including
the Pentagon and government labs. Although machines tend
to reject over 3% of authorized users, the false acceptance
rate (FAR) is less than one in a million. Today, the largest
ap-plication of fingerprint technology is in automated
fingerprint identification systems (AFIS) used by police
forces world widely.
The fingerprint's strength is its acceptance, convenience
and reliability. It takes little time and effort for somebo-dy
using a fingerprint identification device to have his
or her fingerprint scanned. Studieshave also found that
u-sing fingerprints as an identification source is the
least intrusive of all biometric techniques.
Verification of fingerprints is also fast and reliable.
Users experience fewer errors in matching when they use
fingerprints versus many other biometric methods. In addition,
a fingerprint identification device can require very little
space on a desktop or in a machine. Several companies
have produced capture units smaller than a deck of cards.
One of the biggest fears of fingerprint technology is
the theft of fingerprints. Skeptics point out that latent
or re-sidual prints left on the glass of a fingerprint
scanner may be copied. However, a good fingerprint identification
device only detects live fingers and will not acknowledge
fingerprint copies. |
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cleaning and maintenance for water kettle |
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1. Make sure the kettle is cooled down and pull out the plug before cleaning.
2. Never use any scratching,abrasive,caustic cleaners but cotton with proper cleanser to clean the kettle,it would be better to dry it with cloth after cleaning.
3.Never put the kettle or hotplate into water, otherwise it could lead to electric leakage.
4.Different water quality can bring furring, which is no harm to health but affect heating and surface of the kettle.To remove these furring, boil the mixture of vinegar and water by1:2,pour away after one night ,boil water for the second time and then pour away which the kettle can be clean and safe to use.
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Comparison on different methods in boiling water |
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Kettle |
Jar pot |
Drinking machine |
Advantages |
100°boiling water
Hygienic
Fast
Energy saving
safe
convenient |
Keep warm |
Keep warm
Large capacity |
Disadvantages |
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Difficult to clean
High power consumption |
High power consumption
Water is not boiled
Difficult to clean
Easy to be polluted
Always need to buy mineral water
Not to keep fresh |
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Usage Tips |
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Brewing Tea: The temperature varies with different types of tea.The best temperature varies from 75°C to 95°C.
Instant coffee: The ideal temperature for brewing coffee powder is 93°C-95°C.
Milk powder: The temperature for preparing the milk powder for adult can not exceed 70°C, the temperature can not exceed 45°C for baby milk powder.
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