1.txt

This complete matlab for neural network

发信人: ashun (阿顺), 信区: DataMining
标  题: 数据挖掘术语简介（一）
发信站: 南京大学小百合站 (Wed Aug 29 14:41:38 2001)

accuracy 

Accuracy is an important factor in assessing the success of data mining. When 
applied to data, accuracy refers to the rate of correct values in the data. Wh
en applied to models, accuracy refers to the degree of fit between the model a
nd the data. This measures how error-free the model's predictions are. Since a
ccuracy does not include cost information, it is possible for a less accurate 
model to be more cost-effective. Also see precision.

activation function 

A function used by a node in a neural net to transform input data from any dom
ain of values into a finite range of values. The original idea was to approxim
ate the way neurons fired, and the activation function took on the value 0 unt
il the input became large and the value jumped to 1. The discontinuity of this
 0-or-1 function caused mathematical problems, and sigmoid-shaped functions (e
.g., the logistic function) are now used.

antecedent 

When an association between two variables is defined, the first item (or left-
hand side) is called the antecedent. For example, in the relationship "When a 
prospector buys a pick, he buys a shovel 14% of the time," "buys a pick" is th
e antecedent.

API 

An application program interface. When a software system features an API, it p
rovides a means by which programs written outside of the system can interface 
with the system to perform additional functions. For example, a data mining so
ftware system may have an API which permits user-written programs to perform s
uch tasks as extract data, perform additional statistical analysis, create spe
cialized charts, generate a model, or make a prediction from a model.

associations 

An association algorithm creates rules that describe how often events have occ
urred together. For example, "When prospectors buy picks, they also buy shovel
s 14% of the time." Such relationships are typically expressed with a confiden
ce interval. 
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勿以恶小而为之，勿以善小而不为。 —— 刘备

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