Root (surname)

Root is a surname, and may refer to:

People

Root (linguistics)

A root, or a root word, is a word that does not have a prefix (in front of the word) or a suffix (at the end of a word). The root word is the primary lexical unit of a word, and of a word family (root is then called base word), which carries the most significant aspects of semantic content and cannot be reduced into smaller constituents. Content words in nearly all languages contain, and may consist only of root morphemes. However, sometimes the term "root" is also used to describe the word minus its inflectional endings, but with its lexical endings in place. For example, chatters has the inflectional root or lemma chatter, but the lexical root chat. Inflectional roots are often called stems, and a root in the stricter sense may be thought of as a monomorphemic stem.

The traditional definition allows roots to be either free morphemes or bound morphemes. Root morphemes are essential for affixation and compounds. However, in polysynthetic languages with very high levels of inflectional morphology, the term "root" is generally synonymous with "free morpheme". Many such languages have a very restricted number of morphemes that can stand alone as a word: Yup'ik, for instance, has no more than two thousand.

Tree (graph theory)

In mathematics, and more specifically in graph theory, a tree is an undirected graph in which any two vertices are connected by exactly one path. In other words, any acyclic connected graph is a tree. A forest is a disjoint union of trees.

The various kinds of data structures referred to as trees in computer science have underlying graphs that are trees in graph theory, although such data structures are generally rooted trees. A rooted tree may be directed, called a directed rooted tree, either making all its edges point away from the root—in which case it is called an arborescence,branching, or out-tree—, or making all its edges point towards the root—in which case it is called an anti-arborescence or in-tree. A rooted tree itself has been defined by some authors as a directed graph.

The term "tree" was coined in 1857 by the British mathematician Arthur Cayley.

Definitions

Tree

A tree is an undirected graph G that satisfies any of the following equivalent conditions:

Trees in mythology

Trees are significant in many of the world's mythologies and religions, and have been given deep and sacred meanings throughout the ages. Human beings, observing the growth and death of trees, and the annual death and revival of their foliage, have often seen them as powerful symbols of growth, death and rebirth. Evergreen trees, which largely stay green throughout these cycles, are sometimes considered symbols of the eternal, immortality or fertility. The image of the Tree of life or world tree occurs in many mythologies.

Sacred or symbolic trees include the Banyan and the Peepal (Ficus religiosa) trees in Hinduism, the Yule Tree in Germanic mythology, the Tree of Knowledge of Judaism and Christianity, the Bodhi tree in Buddhism and Saglagar tree in Mongolian Tengriism. In folk religion and folklore, trees are often said to be the homes of tree spirits. Germanic paganism as well as Celtic polytheism both appear to have involved cultic practice in sacred groves, especially grove of oak. The term druid itself possibly derives from the Celtic word for oak. The Egyptian Book of the Dead mentions sycamores as part of the scenery where the soul of the deceased finds blissful repose.

Tree (data structure)

In computer science, a tree is a widely used abstract data type (ADT)--or data structure implementing this ADT--that simulates a hierarchical tree structure, with a root value and subtrees of children with a parent node, represented as a set of linked nodes.

A tree data structure can be defined recursively (locally) as a collection of nodes (starting at a root node), where each node is a data structure consisting of a value, together with a list of references to nodes (the "children"), with the constraints that no reference is duplicated, and none points to the root.

Alternatively, a tree can be defined abstractly as a whole (globally) as an ordered tree, with a value assigned to each node. Both these perspectives are useful: while a tree can be analyzed mathematically as a whole, when actually represented as a data structure it is usually represented and worked with separately by node (rather than as a list of nodes and an adjacency list of edges between nodes, as one may represent a digraph, for instance). For example, looking at a tree as a whole, one can talk about "the parent node" of a given node, but in general as a data structure a given node only contains the list of its children, but does not contain a reference to its parent (if any).

2–3–4 tree

In computer science, a 2–3–4 tree (also called a 2–4 tree) is a self-balancing data structure that is commonly used to implement dictionaries. The numbers mean a tree where every node with children (internal node) has either two, three, or four child nodes:

2-node

2-node

3-node

3-node

4-node

4-node

2–3–4 trees are B-trees of order 4; like B-trees in general, they can search, insert and delete in O(log n) time. One property of a 2–3–4 tree is that all external nodes are at the same depth.

2–3–4 trees are an isometry of red–black trees, meaning that they are equivalent data structures. In other words, for every 2–3–4 tree, there exists at least one red–black tree with data elements in the same order. Moreover, insertion and deletion operations on 2–3–4 trees that cause node expansions, splits and merges are equivalent to the color-flipping and rotations in red–black trees. Introductions to red–black trees usually introduce 2–3–4 trees first, because they are conceptually simpler. 2–3–4 trees, however, can be difficult to implement in most programming languages because of the large number of special cases involved in operations on the tree. Red–black trees are simpler to implement, so tend to be used instead.

PoweredUSB

PoweredUSB, also known as Retail USB, USB PlusPower, and USB +Power, is an addition to the Universal Serial Bus standard that allows for higher-power devices to obtain power through their USB host instead of requiring an independent power supply or external AC adapter. It is mostly used in point-of-sale equipment, such as receipt printers and barcode readers.

History

PoweredUSB, as a proprietary variant of USB, was developed and proposed by IBM, Berg (now FCI), NCR and Microsoft between 1998 and 1999, with the last revision (0.8g) issued in 2004. The specification is not endorsed by the USB Implementers Forum (USB-IF). IBM, who owns patents to PoweredUSB, charges a licensing fee for its use.

PoweredUSB was licensed by Hewlett-Packard, Cyberdata, Fujitsu, Wincor and others.

Implementation

PoweredUSB uses a more complex connector than standard USB, maintaining the standard USB 1.x/2.0 interface for data communications and adding a second connector for power. Physically, it is essentially two connectors stacked such that the bottom connector accepts a standard USB plug and the top connector takes a power plug.