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System

Definition: System

System

Noun

1. A group of independent but interrelated elements comprising a unified whole; "a vast system of production and distribution and consumption keep the country going".

2. Instrumentality that combines interrelated interacting artifacts designed to work as a coherent entity; "he bought a new stereo system"; "the unit consists of a motor and a small computer".

3. A complex of methods or rules governing behavior; "they have to operate under a system they oppose"; "that language has a complex system for indicating gender".

4. A procedure or process for obtaining an objective; "they had to devise a system that did not depend on cooperation".

5. A group of physiologically or anatomically related organs or parts; "the body has a system of organs for digestion".

6. An organized structure for arranging or classifying; "he changed the arrangement of the topics"; "the facts were familiar but it was in the organization of them that he was original"; "he tried to understand their system of classification".

7. (physical chemistry) a sample of matter in which substances in different phases are in equilibrium; "in a static system oil cannot be replaced by water on a surface"; "a system generating hydrogen peroxide".

8. The living body considered as made up of interdependent components forming a unified whole; "exercise helped him get the alcohol out of his system".

9. An ordered manner; orderliness by virtue of being methodical and well organized; "his compulsive organization was not an endearing quality"; "we can't do it unless we establish some system around here".

Source: WordNet 1.7.1 Copyright © 2001 by Princeton University. All rights reserved.

Date "system" was first used in popular English literature: sometime before 1321. (references)

Specialty Definition: System

Domain	Definition
Computing	System n. 1. The supervisor program or OS on a computer. 2. The entire computer system, including input/output devices, the supervisor program or OS, and possibly other software. 3. Any large-scale program. 4. Any method or algorithm. 5. `System hacker': one who hacks the system (in senses 1 and 2 only; for sense 3 one mentions the particular program: e.g., `LISP hacker'). Source: Jargon File.
Aerospace	1. Any organized arrangement in which each component part acts, reacts, or interacts in accordance with an overall design inherent in the arrangement. 2. Specifically, a major component of a given vehicle such as a propulsion system or a guidance system. Usually called a major system to distinguish it from the systems subordinate or auxiliary to it.The system of sense 1 may become organized by a process of evolution, as in the solar system, or by deliberate action imposed by the designer, as in a missile system or an electrical system. In sense 2, the system embraces all its own subsystems including checkout equipment, servicing equipment, and associated technicians and attendants. When the term is preceded by such designating nouns as propulsion or guidance, it clearly refers to a major component of the missile. Without the designating noun, the term may become ambiguous. When modified by the word major, however, it loses its ambiguity and refers to a major component of the missile. (references)
Electrical Engineering	A grouping of lines and of other electrical equipment connected for the purpose of conveying electricity from generating stations to the ultimate consumer. Source: European Union. (references)
	The set of interdependent elements constituted to achieve a given objective by performing a specified function. Source: European Union. (references)
Energy	A combination of equipment and/or controls,accessories, interconnecting means and terminal elements by which energy istransformed to perform a specific function, such as climate control, service waterheating, or lighting. [See California Code of Regulations, Title 24, Section 2-5302]. (references)
Federal Student Aid	System is a generic term used for brevity to mean either a major application or a general support system. (references)
Finance	Collection of elements of an auditee that are related one to another in order to achieve an objective. A system includes the inputs, the operations carried out, the resources used to carry out these operations, the outputs produced and the effects of the outputs on the outside world. It also includes the structures used to provide direction for all the elements and to ensure that planned results are achieved. Source: European Union. (references)
Information	A set of elements with relations between the elements such that the set may be looked at as a whole. Source: European Union. (references)
Language	Ring: a mathematical -- for which two binary operations are defined, call them addition and multiplication, such that both operations are commutative and associative. Source: European Union. (references)
Medicine	A set of units combined by nature or art to form an integral, organic, or organized whole. Source: European Union. (references)
Mining	A. A standard, worldwide division; contains rocks formed during a fundamental chronologic unit, a period. An example is the Devonian system b. The fundamental time-rock unit is the system c. In crystallography, the division of first rank, in the classification of crystals according to form. The six systems ordinarily recognized are the isometric, tetragonal, hexagonal, orthorhombic (or rhombic), monoclinic, and triclinic; some divide the hexagonal system into hexagonal and trigonal. d. Applied to the sum of the phases that can be formed from one, two (binary system), three (ternary system), or more components under different conditions of temperature, pressure, and composition e. The term system or general system of work means simply that the work, as it is commenced on the ground is such that, if continued, will lead to a discovery and development of the veins or orebodies that are supposed to be in the claim, or, if these are known, that the work will facilitate theextraction of the ores and mineral. (references)
Post & Telecom	A collection of personnel, machines and methods organised to accomplish a set of specific functions. Source: European Union. (references)
Source: compiled by the editor from various references; see credits.

Specialty Definition: Computer system

(From Wikipedia, the free Encyclopedia)

A computer system is a set of hardware and software which processes data in a meaningful way. A relatively simple computer system is a PC. A relatively complex computer system is the Internet. Even the simplest computer is really a computer system because at least two components (hardware and software) have to work together. But the real meaning of "computer system" comes with interconnection.
Many computer systems can interconnect, that is, join to become a bigger system. Interconnecting computer systems is tricky in the best of cases due to incompatibilities, sometimes between hardware and sometimes software. We can say that the natural inclination of computer systems is not to interconnect themselves. So you have to force them, you have to make them adhere to a set of rules and constraints (protocols), that precisely define the "outside view" of the system. This outside view effectively defines the way a system connects with another. If two systems define the same "outside view", they can interconnect themselves, and become a bigger system of sorts.
This "outside view" comes usually in the form of a standard, that is, a document explaining all the rules to be followed. If your system obeys with all the rules, it can be said to comply with the standard.

See also

computer
internet engineering task force
IEEE standards
legacy system

IBM, Compaq and Dell Computer are PC manufacturing companies.
Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "Computer system."

Law

(From Wikipedia, the free Encyclopedia)

simple:Law
This article is about law in society. For other article subjects named law see law (disambiguation).
This article is concerned with laws of politics and jurisprudence: rules of conduct which mandate and/or proscribe specified relationships among people and organizations; as well as punishments for those who do not follow the established rules of conduct.
In ethics and moral philosophy this type of law is often called a "human legal code" to distinguish it from more fundamental laws applicable to all beings (metaphysics, ontology). Such a body of laws can be seen as a legally-enforced ethical code or as a "secular moral code" (to the degree that political leaders replace religious leaders as moral examples). Because lawyers and jurists more than other professions are self-regulating, almost by definition, they are often held to higher standards of behaviour or at least a stricter etiquette. These concerns are not part of this article, because those expectations and disciplines are specific to each legal code. This article takes an English-speaking point of view and deals with other legal traditions and codes by way of comparison only.

Jurisprudence
Jurisprudence refers to two different things. First, in common law jurisdictions, it means simply "case law", i.e. the law that is established through the decisions of the courts and other officials. Second, it means the philosophy of law, or legal theory, which studies not what the law is in a particular jurisdiction (say, Turkey or the United States) but law in general--i.e. those attributes common to all legal systems.
Jurisprudence in the second sense is conventionally divided into two parts: descriptive, or analytic, jurisprudence, and normative jurisprudence. Analytic jurisprudence studies what law 'is', normative jurisprudence studies what law 'ought to be'.
Among the most important questions of analytic jurisprudence are these: What is a law What is a legal system? What is the relationship between law and power? What is the relationship between law and justice or morality? Does every society have a legal system? How should we understand concepts like legal rights and legal obligations or duties? The most influential works of analytic jurisprudence include: Jeremy Bentham, Of Laws in General; Hans Kelsen, The Pure Theory of Law, H.L.A. Hart, The Concept of Law, and Ronald Dworkin, Law's Empire''.
Among the most important questions of normative jurisprudence are these: What is is the proper function of law? What sorts of acts should be subject to punishment, and what sorts of punishment should be permitted? What is justice? What rights do we have? Is there a duty to obey the law? What value has the rule of law? The most influential works of normative jurisprudence include all the classics of political philosophy. Among contemporary writers, the following have been particularly influential: John Rawls, A Theory of Justice H.L.A. Hart, Punishment and Responsibility; Joel Feinberg, The Moral Limits of the Criminal Law; Joseph Raz, The Morality of Freedom; Ronald Dworkin, A Matter of Principle

Codification of Law
Law is the formal codification of customs which have achieved such acceptance as become the enforced norm. The process of acceptance is accelerated by the existence of legislative bodies which seek to impose laws.
Law codification involves the legislation and regulation of statutes; as well as the resolution of disputes. In the civil law system codification is also an attempt to structure the law according to fundamental ethical principles to create a sense of order and simplicity that all members of society can comprehend, not merely university trained jurists. Stating the law in simple, precise terms, understandable to the lay person without a specialized legal education, is the only way they can reasonably obey it or be fairly sanctioned for not obeying it.
This overlaps with the idea of a formal social legal code as understood in ethics. This may be understandable to the educated lay person but perhaps not to the ordinary lay person. For example, one can explain the idea of precedent more easily than that of the reasonable man, but it may be much harder to explain why precedent is "fair" to one without "higher education". The following are examples of such lay explanations of different branches of law, and theories of law.
They are not comprehensive.

Branches of Law, a sampling
Please note: Wikipedia does not give legal advice.

Administrative law refers to the body of law which regulates bureaucratic managerial procedures and is administered by the executive branch of a government; rather than the judicial or legislative branches (if they are different in that particular jurisdiction). This body of law regulates international trade, manufacturing, pollution, taxation, and the like. This is sometimes seen as a subcategory of civil law and sometimes called public law as it deals with regulation and public institutions.

Canon law refers to laws of the Anglican, Eastern Orthodox, Roman Catholic churches.

Case law (precedental law) regulates, via precedents, how laws are to be understood. Case law, also called common law or judge-made law, is derived from the body of rulings made by a country's courts. In the United States, the primary source of case law relating to federal and constitutional questions is the Supreme Court of the United States. The states, each with its own final court of appeals, generate case law that is only binding precedent in that state. In countries that were once part of the British Empire the Judicial Committee of the Privy Council and the House of Lords are primary sources of case law, though not necessarily binding precedent, as each country has its own court of last resort.

Civil law has three accepted meanings:
Secular law is the legal system of a theocratic government, such as that in England, during the reign of Henry II
Private law seeks to regulate relationships between persons and organizations including contracts and responsible behaviour such as through liability through negligence. This body of law enforces statutes or the common law by allowing a party, whose rights have been violated, to collect damages from a defendant. Where monetary damages are deemed insufficient, civil court may offer other remedies in equity; such as forbiding someone to do an act (eg; an injunction) or formally changing someone's legal status (eg; divorce). This body of law includes the law of torts in common law systems, or in civilian systems, the Law of Obligations.
The civilian legal system or civil law system is the general typology of legal systems found in most countries. It is an alternative to common law system and has its roots in Roman law. It is employed by almost every country that was not a colony of Great Britain. In most jurisdictions the civil law is codified in the form of a civil codes, but in some, like Scotland it remains uncodified. Most codes follow the Code Napolean in some fashion. Notably, the German code was developed from Roman law with reference to German legal tradition.

Commercial law, often considered to be part of civil law, covers business and commerce relations including sales and business entities.

Common law is derived from Anglo-Saxon customary law, also referred to as judge-made law, as it developed over the course of many centuries in the English courts. It is a system of law used in England, many of the states of the United States (except California and Louisiana) and other former British possessions such as in the Laws of Australia, Canada, India, and Ireland.

Criminal law (penal law) is the body of laws which regulate governmental sanctions (such as imprisonment and/or fines) as retaliation for crimes against the social order.

International law governs the relations between states, or between citizens of different states, or international organizations. Its two primary sources are customary law and treaties.

Islamic law (Sharia), is derived from the Koran and used in many Middle Eastern nations; such as in the Laws of Iran and Saudi Arabia.

Procedural Law are rules and regulations found in an legal system that regulate access to legal institutions such as the courts, including the filing of private lawsuits and regulating the treatment of defendants and convicts by the public criminal justice system. Within this field are laws regulating arrests and evidence, injunctions and pleadings. Procedural law defines the procedure by which law is to be enforced. See criminal procedure and civil procedure.

Socialist law is the term for civil law as practiced within states of the former Soviet Union and its satellites; as well as within the Laws of China, Cuba, North Korea, and Vietnam. With the end of the Cold War, most of these nations are incorporating laws compatible with private property and capitalism.

Law as academic discipline and profession
In addition to being part of the societal framework law is also an academic discipline and a profession. Lawyers are sometimes called by other names, as in England where the profession is divided between solicitors and barristers. Sometimes they are also called notaries. They are professionally trained in the United States at graduate schools of law leading to the J.D degree (Juris Doctor). In other countries legal education is considered to start at the undergraduate stage taught in faculty of law leading to the LL.B or B.C.L degrees. NOTE: In Canada at least, the LL.B. requires a previous undergraduate degree to study. Law is an undergraduate degree mainly in civil law countries. Most of these schools also have advanced legal degrees such as the LL.M and the J.S.D degrees. Many persons who attend law school never practice law but use their knowledge of law in another profession. See Law (academic) and jurisprudence For law as a profession, see lawyer, jurist and practice of law.

Further Discussion
Most laws and legal systems --at least in the Western world-- are quite similar in their essential themes, arising from similar values and similar social, economic, and political conditions, and they typically differ less in their substantive content than in their jargon and procedures.
One of the fundamental similarities across different legal systems is that, to be of general approval and observation, a law has to appear to be public, effective, and legitimate, in the sense that it has to be available to the knowledge of the citizen in common places or means, it needs to contain instruments to grant its application, and it has to be issued under given formal procedures from a recognized authority.
In the context of most legal systems, laws are enacted through the processes of constitutional charter, constitutional amendment, legislation, executive order, rulemaking, and adjudication; within Common law jurisdictions, rulings by judges are an important additional source of legal rules.
However, de facto laws also come into existence through custom and tradition. (See generally Consuetudinary law; Anarchist law.)
Law has an anthropological dimension. In order to have a culture of law, people must dwell in a society where a government exists whose authority is hard to evade and generally recognised as legitimate. People forego personal revenge or self-help and choose instead to take their grievances before the government and its agents, who arbitrate disputes and enforce penalties.
This behaviour is contrasted with the culture of honor, where respect for persons and groups stems from fear of the disproportionate revenge they may exact if their person, property, or prerogatives are not respected. Cultures of law must be maintained. They can be eroded by declining respect for the law, achieved either by weak government unable to wield its authority, or by burdensome restrictions that attempt to forbid behaviour prevalent in the culture or in some subculture of the society. When a culture of law declines, there is a possibility that an undesirable culture of honor will arise in its place.
A particular society or community adopts a specific set of laws to regulate the behavior of its own members, to order life in its political territory, to grant or acknowledge the rights and privileges of its citizens and other people who may come under the jurisdiction of its courts, and to resolve disputes.
There are several distinct laws and legal traditions, and each jurisdiction has its own set of laws and its own legal system. Individually codified laws are known as statutes, and the collective body of laws relating to one subject or emanating from one source are usually identified by specific reference. (E.g., Roman law, Common law, and Criminal law.)
Moreover, the several different levels of government each produce their own laws, though the extent to which law is centralized varies. Thus, at any one place there can be conflicting laws in force at the local, regional, state, national, or international levels.
(See conflict of laws, Preemption of State and Local Laws.)

Legal systems and traditions
Anarchist law - Canon law - Civil law - Common law - English Law - European Union Law - International law - Roman law - Scottish Law - Socialist law - Sharia (Islamic law)

Legal subject areas
Administrative law - Admiralty - Alternative dispute resolution - Appellate review - Civil procedure - Civil rights - Commercial law - Comparative law - Consuetudinary law - Contracts - Constitutional law - Courts of England and Wales - Corporations law - Criminal law - Criminal procedure - Environmental law - Equity - Evidence - Family law - Human rights - Immigration - Intellectual property - Jurisprudence - Law and economics - Law of Obligations - Labor law - Land use - List of items for which possession is restricted - Philosophy of law - Practice of law - Private law - Procedural law - Property law - Statutory law - Tax law - Torts - Trusts and Estates - Cyber law

Subjects Auxiliary to Law
Government - Legal history - Law and literature - Political science

Terms, case law, legislation and other resources

Law topics overview
List of jurists
List of legal topics
List of basic criminal justice topics
List of international public law topics

List of Supreme Court of Canada cases
List of Judicial Committees of the Privy Council & House of Lords cases
List of United States Supreme Court cases
List of leading legal cases in copyright law

List of treaties
List of Uniform Acts (United States)
List of United States Federal Legislation

Legal books

Black's Law Dictionary
Halsbury's Laws of England
Corpus Juris Secundum
Recueil Dalloz

Further Reading

Cheyenne Way: Conflict & Case Law in Primitive Jurisprudence, Karl N. Llewellyn and E. Adamson Hoebel, University of Oklahoma Press, 1983, trade paperback, 374 pages, ISBN 0806118555
Other books by Karl N. Llewellyn

See also

law (principle),
religious law,
legal code,
natural law

External link

Law & Legal News & Reference
Directory and Engine to find lawyers by area of expertise and/or by location
Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "Law."

LAW

(From Wikipedia, the free Encyclopedia)

LAW is a US Army light anti-tank weapon
LAW is a law society called Palestinian Society for the Protection of Human Rights
Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "LAW."

Operating system

(From Wikipedia, the free Encyclopedia)

In computing, an operating system (OS) is the system software responsible for the direct control and management of hardware and basic system operations.
Colloquially, the term is most often used to mean all the software which "comes with" a computer system before any applications are installed.
The operating system ensures that other applications are able to use memory, input and output devices and have access to the file system. If multiple applications are running, the operating system schedules these such that all processes have sufficient processor time where possible and do not interfere with each other.

Examples of operating systems

UNIX
GNU/Linux
TOS
Microsoft Windows
Mac OS
MVS
Netware
OpenVMS

Classifications and Terminology
An operating system is conceptually broken into three sets of components: a shell, a kernel and low-level system utilities. As the name implies the shell is an outer wrapper to the kernel which in turn talks directly to the hardware.

Hardware <-> Kernel <-> Shell <-> Applications

In some operating systems the shell and the kernel are completely separate entities, allowing you to run varying combinations of shell and kernel (eg UNIX), in others their separation is only conceptual (eg Windows).
Kernel design ideologies include those of the monolithic kernel, the microkernel and the exokernel. Traditional commercial systems such as UNIX and Windows use a monolithic approach, the trend in more modern systems is to use a microkernel (such as in QNX, BeOS, Windows NT etc) there are a few exceptions such as Linux which still use a monolithic kernel . The microkernel approach is also very popular among research OSes. Many embedded systems use ad-hoc exokernels.

See Also

History of operating systems
List of operating systems
Hard disk drive partitioning
LiveCD OS (Gnoppix and Knoppix Linux).
monolithic kernel -- microkernel -- exokernel
asymmetric and symmetric multiprocessing (SMP) -- clustering -- distributed computing
Operating system advocacy
real-time operating system -- time-share -- multitasking -- embedded system -- single-user -- multi-user
orthogonally persistent -- capabilities versus access control lists
object-oriented operating system

External links

Operating Systems Projects
TUNES Review of Operating Systems
How Operating Systems Work, shown by a tiny self-developed Operating System
Multicians.org and the History of Operating Systems
Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "Operating system."

Solar system

(From Wikipedia, the free Encyclopedia)

simple:Solar System zh-cn:太阳系zh-tw:太陽系
A generic solar system (or planetary system) consists of at least one star and various orbiting objects (such as asteroids, comets, moonss, and planets). The planet Earth is located within our solar system, which is usually just called the solar system; others being referred to as planetary systems to avoid confusion. This terminology will be used below.

Solar system objects
There are a wide variety of objects present in the solar system that fall under various different categories. In recent years many of these categories have been found to be less clear-cut than once thought. This encyclopedia employs the following divisions:

The Sun, a spectral class G2 star that contains 99.86% of system's mass.
The planets of the solar system are those nine bodies traditionally labelled as such; Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto.
Sizeable objects that orbit these planets are moonss. For a complete listing, see that article.
dust and other small particles that orbit these planets form planetary rings
Space debris of artificial origin can be found in orbit around Earth.
The planets were originally formed from planetesimals, sub-planetary bodies that accreted together during the first years of the solar system and no longer exist. The name is also sometimes used to refer to asteroids and comets in general, or to asteroids below 10km in diameter
Asteroids are objects smaller than planets that lie roughly within the orbit of Jupiter and are composed in significant part by non-volatile minerals. They are subdivided into the near-Earth asteroids, which are further subdivided into Atens, Apolloss, and Amors.
Asteroid moons are asteroids that orbit larger asteroids. They are not as clearly distinguished as planetary moons, sometimes being almost as large as their partner.
Trojan asteroids are located in either of Jupiter's L₄ or L₅ points, though the term is also sometimes used for asteroids in any other planetary Lagrange point as well.
Meteoroids are asteroids roughly boulder-sized or smaller, all the way down to dust. Dust within the solar system is responsible for the phenomenon of zodiacal light.
Comets, which are composed largely of volatile ices and whose orbits are highly eccentric, generally having a periapsis within the orbit of the inner planets and an apoapsis out past Pluto. Short-period comets exist with apoapses closer than this, however, and old comets that have had most of their volatiles driven out by solar warming are often categorized as asteroids. Some comets with hyperbolic orbits may also originate outside the solar system.
Centaurss, icy comet-like bodies that have less eccentric orbits that remain in the region between Jupiter and Neptune.
Trans-Neptunian objects, icy bodies whose mean orbital radius lies beyond Neptune's. These are further subdivided:
Kuiper belt objects, with orbits lying between 30 and 50 AU. Thought to be the origin for short-period comets. Pluto is sometimes classified as a Kuiper belt object in addition to being a planet, and a class of Kuiper belt objects with Pluto-like orbits are called Plutinos. The remaining Kuiper belt objects are classified as Cubewanos in the main belt and scattered disk objects in the outer fringes.
Oort cloud objects, currently hypothetical, with orbits lying between 50,000 and 100,000 AU. This region is thought to be the origin of long-period comets.
Small quantities of dust are present throughout the solar system, and is responsible for the zodiacal light. Some of the dust is likely interstellar dust from outside the solar system.
Origin and evolution of planetary systems
Cosmogony is the academic discipline which deals with the formation of planetary systems. Planetary systems are generally believed to form as part of the same process which results in star formation; although, some argue that systems are formed by some kind of accidental "stellar near-collison". The more common theory argues that the objects of a planetary system developed from a solar nebula.

Orbit of the solar system
The solar system is part of the Milky Way galaxy, a spiral galaxy with a diameter of about 100,000 light years containing approximately 200 billion stars, of which our Sun is fairly typical.
Estimates place the solar system at between 25,000 and 28,000 light years from the galactic center. Its speed is about 220 kilometers per second, and it completes one revolution every 226 million years.
The solar system appears to have a very unusual orbit. It is both extremely close to being circular, and at nearly the exact distance at which the orbital speed matches the speed of the compression waves that form the spiral arms. The solar system appears to have remained between spiral arms for most of the existence of life on Earth. The radiation from supernovas in spiral arms could theoretically sterilize planetary surfaces, preventing the formation of large animal life on land. By remaining out of the spiral arms, the Earth may be unusually free to form large animal life on its surface.

Discovery and exploration of the solar system
Because of the geocentric perspective from which humans viewed the solar system, its nature and structure were long misperceived. The apparent motions of solar system objects as viewed from a moving Earth were believed to be their actual motions about a stationary Earth. In addition, many solar system objects and phenomena are not directly sensible by humans without technical aids. Thus both conceptual and technological advances were required in order for the solar system to be correctly understood.
The first and most fundamental of these advances was the Copernican Revolution, which adopted a heliocentric model for the motions of the planets. Indeed, the term "solar system" itself derives from this perspective. But the most important consequences of this new perception came not from the central position of the Sun, but from the orbital position of the Earth, which suggested that the Earth was itself a planet, and the planets other Earths. This was the first indication of the true nature of the planets. Also, the lack of perceptible stellar parallax despite the Earth's orbital motion indicated the extreme remoteness of the fixed stars, which prompted the speculation that they could be objects similar to the Sun, perhaps with planets of their own.

The solar system and other planetary systems
Until recently, the solar system was the only known example of a planetary system, although it was widely believed that other comparable systems did exist. A number of such systems have now been detected, although the information available about them is very limited. The technique employed involves the detection through the Doppler effect of periodic variations in the motion of parent stars which is attributed to the presence of planets. This allows the mass and orbital characteristics of the unseen planets to be determined. Unfortunately the sensitivity of these techniques currently does not permit the detection of planets of mass and orbit comparable to the Earth.

Attributes of Major Planets
All attributes below are measured relative to the Earth:

Planet Equatorial
diameter Mass Orbital
Radius

Mercury 0.382 0.06 0.38

Venus 0.949 0.82 0.72

Earth 1.00 1.00 1.00

Mars 0.53 0.11 1.52

Jupiter 11.2 318 5.20

Saturn 9.41 95 9.54

Uranus 3.98 14.6 19.22

Neptune 3.81 17.2 30.06

Pluto^* 0.24 0.0017 39.5

^*Pluto traditionally has been considered a planet. However now that we have learned more about the variety of bodies in the solar system we can see that its composition and orbit indicate that it has much more in common with Kuiper belt objects than it has with the rest of the planets. Therefore some astronomers no longer class Pluto as a planet.

Other facts
The total surface area of the solar system's objects that have solid surfaces and diameter > 1km is ~ 1.7 × 10⁹ km². ([1])
It has been suggested that the Sun may be part of a binary star system, with a distant companion named Nemesis. Nemesis was proposed to explain some regularities of the great extinctions of life on Earth. The theory says that Nemesis creates periodical perturbations in the asteroids and comets of the solar system causing a shower of large bodies and some of them hit Earth causing destruction of life. After this theory was stated, a search was undertaken for such a dim, distant companion; it found no visible star within one light-year of the Sun.

Mosaic of the planets of the solar system. Note: planets are not portrayed in the same scale.

See also

Laws of Kepler
Titius-Bode law
Planetary nomenclature
Zodiacal light
Timeline of solar system astronomy

The Solar System
Sun - Mercury - Venus - Earth - Mars - Asteroids - Jupiter - Saturn - Uranus - Neptune - Pluto - Comets - Kuiper belt - Oort cloud
Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "Solar system."

Star system

(From Wikipedia, the free Encyclopedia)

The Star system is a practice used in movies in which the biggest movie stars of the day are always given the starring roles.
Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "Star system."

System

(From Wikipedia, the free Encyclopedia)

A system is a conglomeration of related information. A system typically consists of components (or elements) which are connected together in order to facilitate the flow of information, matter or energy. The term is often used to describe a set of entities which interact, and for which a mathematical model can often be constructed.

Introduction
At arbitrary boundaries, a collection of interrelated components may be declared a system and may further be abstracted to be declared a component of a larger system. Systems enable "activites" to be performed. (It's tempting to say that systems enable "things" to be done - but that is confusing in this context.) An engineering example of a system is often a circuit or a physical series.
Depending on the type of system, a system can often be distinguished from individual machines, elements or processes of that system by the number, arrangements and complexity of those elements. For example, a pulley is a machine, but an elevator which is comprised of pulleys, amongst other components, is a system. Going to the doctor is a process, but health care is a system.
It may also be argued that all so-called "things" are actually systems. For example, a cup is a thing, but it is also a system for holding hot or cold liquid, or other material. The cup has a certain shape and a handle, it is made of non-porous material and so on, and it is put together in such a way as to provide a useful function. Describing this thing makes up information, and defines a system.

Types of systems
An open system can be influenced by events outside of the declared boundaries of a system. A closed system is self-contained: outside events can have no influence upon the system. In practice many things are a mixture of the two. For example a prison is a closed system because the prisoners can't get out, and the wardens spend most of their time at the prison. However it is also an open system, because it depends on outside factors and the prisoners and wardens do go outside. Dynamic systems have components or flows or both, that change over time.

Systems in information and computer sciences
In computer science and information science, system could also be a method or an algorithm. Again, an example will illustrate: There are systems of counting, as with Roman numerals , and various systems for filing papers, or catalogues, and various library systems, of which the Dewey Decimal System is an example. This still fits with the definition of components which are connected together (in this case in order to facilitate the flow of information).

Systems in operations research and management science
In operations research and organizational development (OD), organizations are viewed as human systems comprised of interacting components such as sub-systems, processes and organizational structures. Organizational development theorist Peter Senge developed the notion of organizations as systems in his book The Fifth Discipline. Systems thinking has been identified as an important leadership competency where an individual thinks globally when acting locally. He or she takes into account the potential consequences of a decision on other parts of the organization.

See also

Chaos theory
Complex systems
Computer system
Cybernetics
Donella Meadows' twelve leverage points to intervene in a system
General semantics
Meta-systems
Socio-Technical Systems
Solar System
Systems theory
Systems thinking

External links

An introduction to Whole Systems
Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "System."

Systems thinking

(From Wikipedia, the free Encyclopedia)

Systems thinking involves the use of various techniques to study systems of many kinds. It includes studying things in a holistic way, rather than purely reductionist techniques. It aims to gain insights into the whole by understanding the linkages, interactions and processes between the elements that comprise the whole "system".
Systems thinkers consider that:
a "system" is a dynamic and complex whole, interacting as a structured functional unit in equilibrium
information flows between the different elements that compose the system
a system is a community situated within an environment
information flows from and to the surrounding environment via semi-permeable membranes or boundaries
For further details see complex system

Why use systems thinking techniques?
Systems thinkers are particularly interested in studying systems because changing a system frequently leads to counterintuitive system responses. For example feedback loops may operate to either keep the organization in check or unbalance it.

What is a system?
Systems thinking techniques may be used to study any kind of system -- natural, scientific, human, or conceptual.

Examples
Systems thinking often involves considering a "system" in different ways:
Rather than trying to improve the braking system on a car by looking in great detail at the composition of the brake pads (reductionist), the boundary of the braking system may be extended to include not only the components of the car, but the driver, the road and the weather, and considering the interactions between them.

Looking at something as a series of conceptual systems according to multiple viewpoints. A supermarket could be considered as a "profit making system" from the perspective of management, an "employment system" from the perspective of the staff, and a "shopping system" -- or perhaps an "entertainment system" -- from the perspective of the customers. As a result of such thinking, new insights may be gained into how the supermarket works, why it has problems, or how changes made to one such system may impact on the others.

Methodologies
Systems thinking uses a variety of techniques that may be divided into:
Hard systems - involving simulations, often using computers and the techniques of operations research. Useful for problems that can justifiably be quantified. However it cannot easily take into account unquantifiable variables (opinions, culture, politics, etc), and may treat people as being passive, rather than having complex motivations.
Soft systems - Used to tackle systems that cannot easily be quantified, especially those involving people interacting with each other or with "systems". Useful for understanding motivations, viewpoints, and interactions but, naturally, it doesn't give quantified answers. Soft systems is a field that the academic Peter Checkland has done much to develop.

Application
Systems thinking is increasing being used to tackle a wide variety of subjects in fields such as management, computing, and the environment.

See also

Emergence
Leadership development
List of management topics
Organizational Development

INDEX
1. Definition
2. Synonyms
3. Crosswords
4. Usage: Modern 5. Usage: Commercial
6. Images: Slideshow
7. Images: Photo Album
8. Images: Digital Art 9. Sounds
10. Quotations: Familiar
11. Quotations: Historic
12. Quotations: Fiction 13. Quotations: Non-fiction
14. Quotations: Spoken
15. Quotations: Speeches
16. Usage Frequency 17. Names: Company Usage
18. Expressions
19. Expressions: Internet
20. Translations: Modern 21. Translations: Ancient
22. Bible Trace
23. Abbreviations
24. Acronyms 25. Derivations
26. Rhymes
27. Anagrams
28. Bibliography

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