Encyclopedian Dictionary

Expert system

Expert system

A computer program that behaves like an expert consultant in predictions of outcomes or events and diagnosing problems. It performs this function by referral to a large database of specific knowledge in a specialized area and using structured rules of inference to draw conclusions.

An outgrowth of artificial intelligence research lead to the development of the first expert system called Dendral a program that was used in chemical analysis and was designed by Edward Feigenbaum of Stanford University in the 1960's. In 1975, another expert system program was introduced named Mycin was developed that diagnoses bacterial infections. By the end of the 1980s, several thousand such expert systems had been created for diverse purposes such as credit risks, configuration of computer networks and providing mechanics with advise.

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Africa

Pronunciation key

( af′ri-kə )

Af•ri•ca

Among earth's continents, Africa is the second largest of all and situated in the Eastern hemisphere. The continent is located south of Europe between the Atlantic and Indian Oceans. Its total size has a capacity of 11,500,000 square miles. Historically it was called the Dark Continent.

Exploration and Discovery in Africa

Africa remained primarily a mystery to people around the world until the late 1700's.

Exploration of the African interior was a slow process. Between 1768-1773 A Scot, James Bruce, had gone through Abyssinia (Ethiopia) and located the source of the Blue Nile.

A group of British scholars formed the African Association in 1788 to promote exploration of the continent. Expeditions for the Association up the Niger River were led by another Scot, explorer Mungo Park between 1795-1796 and again in 1805. The River's complete course was not determined until 1830, when John and Richard Lander sailed down it.

Exploration by Europeans reached its peak during the 19th century due to economic or political expansion or in support of scientific investigation, most European nations encouraged exploration of the traditionally "dark" continent. English explorer Alexander Gordon Laing became the first European to reach Timbuktu in 1828, today known as Mali, but then the location served as a center of trade.

In 1828, French explorer René Caillié visited Timbuktu and followed up with an expedition to cross the Sahara.

The Royal Geographic Society founded in 1830, supported the search conducted by British explorers for the source of the White Nile, a southern branch of the Nile River, which lead to further expeditions of eastern Africa. English explorers Richard Burton and John Hanning Speke (1857-1859), reached Lake Tanganyika in 1858, which forms part of the border between Zaire and Tanzania. Together they discovered Lake Tanganyika and from there, Speke continued to discover nearby Lake Victoria, alone. He returned again to extend his exploration of Lake Victoria from 1841-1856, providing evidence the lake was the source of the White Nile. Burton disagreed. In 1862, Speke and James Grant discovered where Lake Victoria emptied into a river. Samuel W. Baker confirmed that this was the Nile, who came up the river from the Sudan in 1864.

The Scottish medical missionary, David Livingston became the most well-known of explorers in Africa. Chiefly he worked in the Zambesi region. He traveled across southern and southwest Africa, reaching Luanda in what is today known as Angola. Those expeditions lasted from 1841-1856. Then, Livingstone journeyed east, tracing the Zambezi River across the continent. Between 1858-1863 Livingstone explored the African southeast reaching Lake Nyasa in Tanzania and then in 1866, traveled again through east central Africa until his death in 1873.

Henry Morton Stanley, a reporter for the New York Herald and London newspapers, traveled to Africa in 1869 in search of Livingstone who had not been heard from in several years. He was discovered by Stanley near Lake Tanganyika in 1871. The story captured the imagination of people around the world. Stanley wished to continued in Livingstone's explorations, and set out on an expedition 1874-1877, following the course of the Congo River to the sea.

References and Further Reading

expunction

Pronunciation key

( ik-spuŋk′shən )

ex•punc•tion

[L. expungere expunct- to strike out < LL. expunctio < L. expunctus, pp.].

The act of expunging or being expunged. A deletion.

References and Further Reading

expressman

Pronunciation key

( iks-pres′mən )

expressman

n. [pl. EXPRESSMEN (-mən)]

One who has been hired by an express agency. A driver of an express vehicle who delivers and collects packages.

References and Further Reading

expressionistic

Pronunciation key

( iks-presh′ən-is′tik )

ex•pres•sion•is•tic

adj.

Expressionist.

References and Further Reading

express

Pronunciation key

( iks-pres′ )

ex•press

v.t. [EXPRESSED, EXPRESSING, EXPRESSES.]

[ME. expressen; OFr. expresser, espresser < L. ex- out + pressare press; < Med. L. expressare see PRESS].

To press or squeeze out; extract.
To achieve by using pressure; eliciting by force; extort.
To put into words; representing by language. To communicate such as by a gesture. To state or show.
To make known such as one's opinion or feelings; to reveal; to put forth in words; make emotional display such as he expressed sorrow.
To represent, picture or symbolize in music, art, etc.
To express by representation or a sign; symbolize; signify such as the sign "%" symbolizes percent. To make a depiction of.
To dispatch by express mail, rapid transport; shipping, etc.

adj.

[ME. expresse; OFr. expres; L. expressus, pp. of exprimere < ex-, out + premere; see PRESS.]

Definitively expressed, not implied; explicitly stated; therefore
Exact such as an express image.
For a particular, special or definitive purpose such as express reason for attending, therefore,
(Originally, for the express purpose of running to one station.) Quickly, direct with few obstructions such as express train distinguished from local, therefore,
Characterized by speed or velocity; namely,
- Sent out with fast speed; for fast driving, direct and rapid, presumably non-stop such as an express highway.
- High speed, such as an express bullet.
- For high-speed projectiles such as an express rifle.
- Having to do with railway express, pony express, etc.

A special courier or messenger.
Swiftly delivered goods or mail by such a courier, or a business which is concerned with operating such a system.
- Express train, bus, truck, or other vehicle employed for such a dispatch which makes few stops or runs non-stop before reaching its destination.
- Express rifle.
The Pony express.
Method or service which transports goods and dispatching money rapidly; express typically costs more than freight.
Goods or money transported or dispatched by express service.
Any means that transmits or transfers goods or services swiftly, usually non-stop.
A concern of any business which operates through such a system.

— express oneself

Stating of one's thoughts.
Expressing of one's feelings, imaginative thoughts, etc. especially in a context that is artistic or creative.

—ex•press′er n. —ex•press′i•ble adj.

Abbreviated. exp.

An Express Company is organized to provide quick, secure deliveries of messages, goods or monetary services by railroad or other common carriers, which include pickup from the consignor and delivery to the consignee. The express industry in the U.S. is due to outgrowth of the custom under which stagecoach drivers, railroad conductors and others were entrusted with parcels and product delivery. These services are now provided by railroads and major airlines.

The express system began in 1839 by William Harnden of Boston (1813-1845), a former railroad conductor who undertook transport of packages and documents between New York and Boston and to carry out commissions for merchants in these cities. Ready demand for express delivery service made it necessary to employ more messengers, several individuals whom later started their own express services in other sections of America. In 1849 the Adams Express co. was established. In 1852 Wells, Fargo and Co., and in 1855 the American-Eruopean Co. One of these men was Henry Wells, who with William G. Fargo, a banker, organized the Wells Company in 1845 which later merged with the Livingston Company to form the American Express Company. Wells and Fargo established an express service in 1852 to serve California and the Far West. Later, it was acquired by the Holladay Overland Mail and Express Company. It retained the name Wells, Fargo and Company and provided express and banking services to the western gold miners and other pioneers. It carried mail and bullion across the plains in stage coaches. A more notable part of its operation was the pony express. With the nationwide introduction of the railroad, the express service was ultimately extended to operations on the Atlantic seaboard.

^{Image credit: Railway Express Agency}
The Overland coash begins an eastbound journey from San Francisco in the 1850's. Mail and express were transported to Salt Lake City and to St. Joseph, Missouri via Sacramento.

With the expansion of railroads, other express companies were established but in 1914, consolidations reduced the number to seven. Those included Adams, American, Wells Fargo, Southern, Great Northern, Western and Northern. Each of these companies operated within a separate territory under contracts with individual railroads whose lines it used. Express companies were radically changed in 1918 when the railroads were placed under federal control due to the war program. All existing express companies were then consolidated under the name American Railway Express Company. This newly established company controlled all express operations in the railway system as an agent of the director-general of railroads, William G. McAdoo. The railroads were returned to private control in 1920 and the company continued operations under agreements with the individual railroads. In 1921 some railroads in the Southeast established a separate company known as the Southeastern Express Company. It retired from business in the year 1938. In 1929 the railroads purchased all of the American Railway Express company's property and established the Railway Express Agency. This new company issued capital stock which was sold to the railroads, followed by other railroads entering into an operating agreement with them.

^{Image credit: Railway Express Agency}
Air express cargo is loaded into a shipment transport headed overseas. Established in 1927, air express transport now provides U.S. shippers with quick delivery service worldwide.

Since WWI, demand for express railroad service has steadily declined due to competition from parcel post (first established in 1913), motor vehicle transportation and airline freight carriers. Express service by airlines was started in 1927, and the Air Express Division of the Railway Express Agency handled all the express freight carried by the major airlines from 1936. It also maintained interchange arrangements with foreign airlines for package transport between the United States and European, African, Middle Eastern and Far East nations. Further arrangements were made for surface express service by ship, to West Germany and Japan in 1956.

In 1960, Railway Express maintained 13,500 trucks in its pickup and delivery fleet and used about 2800 refrigeration vehicles equipped to travel at the fastest passenger train speeds. Their freight included all varieties of commodities, live animals, and a large volume of perishable freight that required timely delivery. The majority of long distance express traffic was carried in cars moving in fast passenger trains. Some special trains were devoted exclusively to express shipments and operated between important business centers.

The American Express Company, one of the original firms in this field, quit the express freight business with the 1918 consolidation. It continued to operate in foreign travel service, travelers checks, foreign exchange banking, and international freight forwarding.

Syn. explicit, utter.