(Basic Units)
LENGTH
Unit
Abbreviation
Number of Meters
Approximate U.S. Equivalent
kilometer
km
1,000
0.62 mile
hectometer
hm
100
328.08 feet
deka meter
dam
10
32.81 feet
meter
m
1
39.37 inches
decimeter
dm
0.1
3.94 inches
centimeter
cm
0.01
0.39 inch
millimeter
mm
0.001
0.039 inch
micrometer
|jm
0.000001
0.000039 inch
AREA
Unit
Abbreviation
Number of Square Meters
Approximate U.S. Equivalent
square kilometer
sq km or km 2
1,000,000
0.3861 square miles
hectare
ha
10,000
2.47 acres
are
a
100
119.60 square yards
square centimeter
sq cm or cm 2
0.0001
0.155 square inch
VOLUME
Unit
Abbreviation
Number of Cubic Meters
Approximate U.S. Equivalent
cubic meter
m 3
1
1.307 cubic yards
cubic decimeter
dm 3
0.001
61.023 cubic inches
cubic centimeter
cu cm or cm 3 also cc
0.000001
0.061 cubic inch
CAPACITY
Unit
Abbreviation
Number of Liters
Approximate U.S. Equivalent
cubic dry liquid
kiloliter
ki
1,000
1.31 cubic yards
hectoliter
hi
100
3.53 cubic feet 2.84 bushels
dekaliter
dal
10
0.35 cubic foot 1.14 pecks 2.64 gallons
liter
i
1
61.02 cubic inches 0.908 quart 1.057 quarts
cubic decimeter
dm 3
1
61.02 cubic inches 0.908 quart 1.057 quarts
deciliter
di
0.10
6.1 cubic inches 0.18 pint 0.21 pint
centiliter
cl
0.01
0.61 cubic inch 0.338 fluid ounce
milliliter
ml
0.001
0.061 cubic inch 0.27 fluid dram
microliter
Ml
0.000001
0.000061 cubic inch 0.00027 fluid dram
MASS AND WEIGHT
Unit
Abbreviation
Number of Grams
Approximate U.S. Equivalent
metric ton
t
1,000,000
1.102 short tons
kilogram
k 9
1,000
2.2046 pounds
hectogram
h 9
100
3.527 ounces
dekagram
dag
10
0.353 ounce
gram
9
1
0.035 ounce
decigram
d g
0.10
1.543 grains
centigram
c 9
0.01
0.154 grain
milligram
mg
0.001
0.015 grain
microgram
M9
0.000001
0.000015 grain
*For metric equivalents of U.S. units, see Weights and Measurements table
time conversation over the network became possible with the development of Internet Relay Chat protocols (see chat). In 1990 ARPANET ceased to exist, leaving behind the NSFNET, and the first commercial dial-up access to the Internet became available. In 1991 the World Wide Web was released to the public (via FTP). The Mosaic browser was released in 1993, and its popularity led to the proliferation of World Wide Web sites and users. In 1995 the NSFNET reverted to the role of a research network, leaving Inter¬ net traffic to be routed through network providers rather than NSF super¬ computers. That year the Web became the most popular part of the Internet, surpassing the FTP protocols in traffic volume. By 1997 there were more than 10 million hosts on the Internet and more than 1 million registered domain names. Internet access can now be gained via radio signals, cable- television lines, satellites, and fibre-optic connections, though most traffic still uses a part of the public telecommunications (telephone) network. The Internet is widely regarded as a development of vast significance that will affect nearly every aspect of human culture and commerce in ways still only dimly discernible.
Internet Protocol address See IP address
Internet service provider (ISP) Company that provides Internet connections and services to individuals and organizations. For a monthly fee, ISPs provide computer users with a connection to their site (see data transmission), as well as a log-in name and password. They may also pro¬ vide software packages (such as browsers), e-mail accounts, and a personal Web site or home page. ISPs can host Web sites for businesses and can also build the Web sites themselves. ISPs are all connected to each other through network access points, public network facilities on the Internet backbone.
Interpol officially International Criminal Police Organiza¬ tion International organization whose purpose is to fight international crime. Interpol promotes the widest possible mutual assistance between the criminal police authorities of affiliated countries and seeks to estab¬ lish and develop all institutions likely to contribute effectively to the pre¬ vention and suppression of ordinary crime. The organization traces its
© 2006 Encyclopaedia Britannica, Inc.
952 I interpolation ► intonation
history to 1914, when a congress of international criminal police, attended by delegates from 14 countries, was held in Monaco. Interpol was for¬ mally founded in Austria in 1923 with 20 member countries; after World War II its headquarters moved to Paris and, in 1989, to Lyon, France. By the early 21st century, its membership exceeded 180 countries. Interpol pursues criminals who operate in more than one country (e.g., smugglers), those who stay in one country but whose crimes affect other countries (e.g., counterfeiters of foreign currency), and those who commit a crime in one country and flee to another.
interpolation In mathematics, estimation of a value between two known data points. A simple example is calculating the mean (see mean, median, and mode) of two population counts made 10 years apart to estimate the population in the fifth year. Estimating outside the data points (e.g., pre¬ dicting the population five years after the second population count) is called extrapolation. If more than two data points are available, a curve may fit the data better than a line. The simplest curve that fits is a poly¬ nomial curve. Exactly one polynomial of any given degree—an interpo¬ lating polynomial—passes through any number of data points.
interrogation In criminal law, process of formally and systematically questioning a suspect in order to elicit incriminating responses. The pro¬ cess is largely outside the governance of law, though in the U.S. relatively elaborate safeguards have been placed on police interrogatory powers in order to protect the rights of the accused.
interstate commerce In the U.S., any commercial transaction or traf¬ fic that crosses state boundaries or that involves more than one state. Gov¬ ernment regulation of interstate commerce is founded on the commerce clause of the Constitution (Article I, section 8), which authorizes Congress “To regulate Commerce with foreign Nations, and among the several States, and with Indian Tribes.” The Interstate Commerce Commission, estab¬ lished in 1887, was originally intended to regulate the railroad industry; its jurisdiction was later expanded to include trucks, ships, freight forwarders, and other interstate carriers. The Sherman Act (1890), followed by the Clayton Act (1914), made illegal any act that tended to interfere with free competition between and among industries, businesses, and any interstate commercial venture. The Federal Trade Commission (FTC) was estab¬ lished by the Federal Trade Commission Act of 1914, which gave the FTC powers—judicial, legislative, and executive—to administer the Sherman and Clayton acts. The Federal Communications Commission (FCC) was created to protect the right of the public to the airwaves through licensing and oversight of the practices of broadcasters in radio and television. In the 20th century, court decisions tended to interpret interstate commerce broadly, thus allowing Congress to regulate a wide variety of activities by which interstate commerce could be affected, even if they took place within the borders of a single state. One such decision was Heart of Atlanta Motel v. U.S. (1964), in which the Supreme Court upheld the prohibition of dis¬ crimination in public accommodations contained in the 1964 Civil Rights Act on the ground that the discriminatory practices of a business operating in only one state could affect interstate commerce.