In computer science, an AVL tree is a self-balancing binary search tree, and it was the first such data structure to be invented.

In an AVL tree, the heights of the two child subtrees of any node differ by at most one.

In other words AVL tree is a binary search tree where the height of the left subtree differs from the height of the right subtree by at most 1 level, if it exceeds 1 level then rebalancing occurs.

The AVL tree is named after its two Soviet inventors, G. M. Adelson-Velskii and E. M. Landis, who published it in their 1962 paper " An algorithm for the organization of information.

Basic operations of an AVL tree involve carrying out the same actions as would be carried out on an unbalanced binary search tree, but modifications are preceded or followed by one or more operations called tree rotations, which help to restore the height balance of the subtrees.

Lookup in an AVL tree is performed exactly like in any unbalanced binary search tree.

* AVL tree applet – all the operations

* Self balancing AVL tree with Concat and Split operations

The AVL tree is another structure supporting O ( log n ) search, insertion, and removal.

Tree rotations are used in a number of tree data structures such as AVL trees, red-black trees, splay trees, and treaps.

Pictorial description of how rotations cause rebalancing in an AVL tree.

A type of tree which uses this rebalancing technique is the AVL tree.

* AVL tree, red-black tree, and splay tree, kinds of binary search tree data structures that use rotations to maintain balance.

** AVL tree

* AVL tree

GSM and EVDO are the most common services applied, because of the low data rate needed for AVL, and the low cost and near-ubiquitous nature of these public networks.

Large private telelocation or AVL systems send data from GPS receivers in vehicles to a dispatch center over their private, user-owned radio backbone.

The main purpose of using AVL is not only to locate the vehicles, but also to obtain information about engine data, fuel consumption, driver data and sensor data from i. e. doors, freezer room on trucks or air pressure.

Such data can be obtained via the CAN-bus, via direct connections to AVL systems or via open bus systems such as UFDEX that both sends and receives data via SMS or GPRS in pure ASCII text format.

Another scenario for sensor functions is to connect the AVL to driver information, to collect data about driving time, stops, or even driver absence from the vehicle.

The AVL display for a vehicle at the Heart Butte Post Office in Montana shows a latitude and longitude of 48. 28333 N ,-112. 83583 W. The CAD system uses degrees-minutes-seconds format data and shows the same location as 481700N, 1125009W.

AVL technology is predominately used when applying vehicle tracking to fleet or driver management solutions.

A dispatch facility used by Denver, Colorado | Denver RTD features a radio communication consoles and a GPS-based Automatic vehicle location | AVL system.

If an AVL system is used, the CAD system will look through a list of most recent reported vehicle positions.

For example, where everyone is used to the convenience of automatic vehicle location ( AVL ), an AVL outage can suddenly increase staff workloads.

Automatic vehicle location ( AVL ) systems are sometimes used to help the dispatch center staff determine the closest tow truck.

While not having state of the art facilities, the factory was equipped with a " Borghi e Severi " dyno bench and related AVL datalogging computers, which was used for the development of the W12 motor, standard toolshop machines, and a warehouse.

MDTs may be simple display and keypad units, intended to be connected to a separate black-box or AVL ( see below ) computer.

* Binary tree, a computer tree data structure in which each node has at most two children

In computer science, a binary tree is a tree data structure in which each node has at most two child nodes, usually distinguished as " left " and " right ".

In a language with records and references, binary trees are typically constructed by having a tree node structure which contains some data and references to its left child and its right child.

In languages with tagged unions such as ML, a tree node is often a tagged union of two types of nodes, one of which is a 3-tuple of data, left child, and right child, and the other of which is a " leaf " node, which contains no data and functions much like the null value in a language with pointers.

Binary trees can also be stored in breadth-first order as an implicit data structure in arrays, and if the tree is a complete binary tree, this method wastes no space.

If the tree contains data, we can simply simultaneously store it in a consecutive array in preorder.

In computer science, a B-tree is a tree data structure that keeps data sorted and allows searches, sequential access, insertions, and deletions in logarithmic time.

Modern methods include the use of lossless data compression for incremental parsing, prediction suffix tree and string searching by factor oracle algorithm ( basically a factor oracle is a finite state automaton constructed in linear time and space in an incremental fashion ).

Such predictions were called into question by 1995 data that show that within regions of Southeast Asia much of the original forest has been converted to monospecific plantations, but that potentially endangered species are few and tree flora remains widespread and stable.

If a more sophisticated data structure ( e. g., heap or binary tree ) is used, the time required for searching and insertion can be reduced significantly ; this is the essence of heap sort and binary tree sort.

As one of the earliest programming languages, Lisp pioneered many ideas in computer science, including tree data structures, automatic storage management, dynamic typing, and the self-hosting compiler.

* 1994 US Patent 5, 282, 222 for wireless data transmission-The patent " tree " rooted on this patent has upwards of 20, 000 nodes and leaves references.

For morphological data, unfortunately, the only objective way to determine convergence is by the construction of a tree – a somewhat circular method.

Another important factor that affects the accuracy of tree reconstruction is whether the data analyzed actually contain a useful phylogenetic signal, a term that is used generally to denote whether a character evolves slowly enough to have the same state in closely related taxa as opposed to varying randomly.

In general, the more data that is available when constructing a tree, the more accurate and reliable the resulting tree will be.

The fewer characters that have missing data, the better ; concentrating the missing data across a small number of character states produces a more robust tree.