Tuesday, September 20, 2005
LAN
A local area network (LAN) is a computer network covering a local area, like a home, office or small group of buildings such as a college.
When using ethernet the computers are usually wired to a hub or to a switch. This constitutes the physical layer.
A layout known as a spanning tree protocol is often used to maintain a loop free network topology within a LAN, particularly with ethernet.
A number of network protocols may use the basic physical layer including TCP/IP. In this case DHCP is a convenient way to obtain an IP address rather than using fixed addressing. LANs can be interlinked by connections to form a Wide area network. A router is used to make the connection between LANs.
LANs are distinguished from other kinds of networks by three characteristics: (1) their size, (2) their transmission technology, and (3) their topology.
When using ethernet the computers are usually wired to a hub or to a switch. This constitutes the physical layer.
A layout known as a spanning tree protocol is often used to maintain a loop free network topology within a LAN, particularly with ethernet.
A number of network protocols may use the basic physical layer including TCP/IP. In this case DHCP is a convenient way to obtain an IP address rather than using fixed addressing. LANs can be interlinked by connections to form a Wide area network. A router is used to make the connection between LANs.
LANs are distinguished from other kinds of networks by three characteristics: (1) their size, (2) their transmission technology, and (3) their topology.
Sunday, September 18, 2005
Gravity
Gravity is the force of attraction between massive particles. Weight is determined by the mass of an object and its location in a gravitational field. While a great deal is known about the properties of gravity, the ultimate cause of the gravitational force remains an open question. General relativity is the most successful theory of gravitation to date. It postulates that mass and energy curve space-time, resulting in the phenomenon known as gravity.
The first mathematical formulation of gravity was published in 1687 by Sir Isaac Newton. His law of universal gravitation was the standard theory of gravity until work by Albert Einstein and others on general relativity. Since calculations in general relativity are complicated, and Newtonian gravity is sufficiently accurate for calculations involving weak gravitational fields (e.g., launching rockets, projectiles, pendulums, etc.), Newton's formulae are generally preferred.
Steven Weinberg noted that we would still build a suspension bridge to modern gravity theory with Newton's laws. Newton's theory is much simpler than general relativity, and used very often, so it is usually taught first.
The first mathematical formulation of gravity was published in 1687 by Sir Isaac Newton. His law of universal gravitation was the standard theory of gravity until work by Albert Einstein and others on general relativity. Since calculations in general relativity are complicated, and Newtonian gravity is sufficiently accurate for calculations involving weak gravitational fields (e.g., launching rockets, projectiles, pendulums, etc.), Newton's formulae are generally preferred.
Steven Weinberg noted that we would still build a suspension bridge to modern gravity theory with Newton's laws. Newton's theory is much simpler than general relativity, and used very often, so it is usually taught first.
Precipitation (meteorology)
In meteorology, precipitation is any kind of water that falls from the sky as part of the weather. This includes snow, rain, sleet, freezing rain, hail, and virga. Precipitation is a major part of the hydrologic cycle, and is responsible for depositing most of the fresh water on the planet. Precipitation is generated in clouds, which reach a point of saturation; at this point larger and larger droplets (or pieces of ice) form, which then fall to the earth under gravity. It is possible to 'seed' clouds to induce precipitation by releasing a fine dust or appropriate chemical (commonly silver nitrate) into a cloud, encouraging droplets to form, and increasing the probability of precipitation.
Judicial branch
The Supreme Court of North Carolina is the state's highest appellate court; it numbers seven justices. the North Carolina Court of Appeals is the only intermediate appellate court in the state; it consists of fifteen judges who rule in rotating panels of three. Together, the Supreme Court and Court of Appeals constitute the Appellate division of the court system.
The Trial division includes the Superior Court and the District Court. All felony criminal cases, civil cases involving more than $10,000 and misdemeanor and infraction appeals from District Court are tried in Superior Court. A jury of 12 hears the criminal cases. In the civil cases, juries are often waived.
Civil cases such as divorce, custody, child support and cases involving less than $10,000 are heard in District Court, along with criminal cases involving misdemeanors and infractions. The trial of a criminal case in District Court is always without a jury. The District Court also hears juvenile cases involving children under the age of 16 who are delinquent and children under the age of 18 who are undisciplined, dependent, neglected or abused. Magistrates accept guilty pleas for minor misdemeanors, accept guilty pleas for traffic violations and accept waivers of trial for worthless-check cases among other things. In civil cases, the magistrate is authorized to try small claims involving up to $4,000 including landlord eviction cases.
The Trial division includes the Superior Court and the District Court. All felony criminal cases, civil cases involving more than $10,000 and misdemeanor and infraction appeals from District Court are tried in Superior Court. A jury of 12 hears the criminal cases. In the civil cases, juries are often waived.
Civil cases such as divorce, custody, child support and cases involving less than $10,000 are heard in District Court, along with criminal cases involving misdemeanors and infractions. The trial of a criminal case in District Court is always without a jury. The District Court also hears juvenile cases involving children under the age of 16 who are delinquent and children under the age of 18 who are undisciplined, dependent, neglected or abused. Magistrates accept guilty pleas for minor misdemeanors, accept guilty pleas for traffic violations and accept waivers of trial for worthless-check cases among other things. In civil cases, the magistrate is authorized to try small claims involving up to $4,000 including landlord eviction cases.
