basic algorithms for data mining a brief overview

Data Preparation for Data Mining- P3

Ngày tải lên : 24/10/2013, 19:15

... representation 2.6.2 Building Data Dealing with Variables The data representation can usefully be looked at from two perspectives: as data and as a data set The terms data and data set” are used to describe ... tools affect what is done • The stages of data preparation and what needs to be decided at each stage The fundamental purpose of data preparation is to manipulate and transform raw data so that ... scaffolding in place and adding many instances of measured values is what makes a data set Superstructure plus instance values equals data sets 2.6.1 Data Representation The sort of data that...

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Data Preparation for Data Mining- P4

Ngày tải lên : 24/10/2013, 19:15

... sort of normalization used in a database Recall that the assumption for this discussion is that the data is present as a single table Putting data into its various normal forms in a database requires ... with a single step.” Basic data preparation requires three such steps: data discovery, data characterization, and data set assembly • Data discovery consists of discovering and actually locating ... detailed data is preferred to aggregated data for mining But the level of aggregation is a continuum Even detailed data may actually represent an aggregation FNBA may be able to obtain outstanding...

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Data Preparation for Data Mining- P5

Ngày tải lên : 29/10/2013, 02:15

... original information This additional information actually forms another data stream and enriches the original data Enrichment is the process of adding external data to the data set Note that data ... the character of a physical data set as opposed to a behavioral data set Physical data sets measure mainly physical characteristics about the world: temperature, pressure, flow rate, rainfall, ... Its main interaction is with a variable _Q_MVP This is a variable that does not exist in the original data set The data preparation software creates this variable and captures information about...

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Data Preparation for Data Mining- P6

Ngày tải lên : 29/10/2013, 02:15

... variable variability is representative of the original data sample Random sampling does that If the original data set represents a biased sample, that is evaluated partly in the data assay (Chapter ... this chapter are not needed—at least not for numerating alpha values Data sets containing exclusively alpha values cannot reflect or be calibrated against associated numeric values in the data set ... important as in numerical variables (Recall this is not a new variable type, just a clearer name for qualitative variables—nominals and categoricals—to save confusion.) A measure of variability in alpha...

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Data Preparation for Data Mining- P7

Ngày tải lên : 08/11/2013, 02:15

... variables can also be appropriately placed on this map The values of an alpha variable are labels The numeration method associates each label with some appropriate particular “area” on the state ... the alpha values and the system of variables as a whole that allows their appropriate numeration Numeration does not recover the actual values appropriate for an alpha variable, even if there are ... ordering As with most other alpha labels, appropriate numeration adds to the information available for modeling Inappropriate labeling at best makes useful information unavailable, and at worst,...

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Data Preparation for Data Mining- P8

Ngày tải lên : 08/11/2013, 02:15

... in each variable In any practically modelable data set, there are always far more instances of data available and usually far more variables and alpha labels to be considered The numeration process ... preparing the data, all of the variables in a data set have a numerical representation Chapter explained why and how to find a suitable and appropriate numerical representation for alpha values—that ... introducing as little distortion as possible, and is tolerant of out-of-range values Range normalization addresses a problem with a variable’s range that arises because the data used in data preparation...

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Data Preparation for Data Mining- P9

Ngày tải lên : 08/11/2013, 02:15

... normal nor regular, as is almost invariably the case with real-world data sets—particularly behavioral data sets—these tools cannot perform as designed In many cases they simply are not able ... instance values is duplicated Alpha labels, for instance, all have identical numerical values for a single label There is no way to spread out the values of a single label Binary values also are ... important to avoid adding bias and distortion to the data as it is to make the information that is present available to the mining tool The data itself, considered as individual variables, is fairly...

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