Applications and Types of Cluster Analysis

Applications and Types of Cluster Analysis

•It is widely used in image processing, data analysis, and pattern recognition.

•It helps marketers to find the distinct groups in their customer base and they can characterize their customer groups by using purchasing patterns.

•It can be used in the field of biology, by deriving animal and plant taxonomies and identifying genes with the same capabilities.

•It also helps in information discovery by classifying documents on the web.

Advantages of Cluster Analysis:

1.It can help identify patterns and relationships within a dataset that may not be immediately obvious.

2.It can be used for exploratory data analysis and can help with feature selection.

3.It can be used to reduce the dimensionality of the data.

4.It can be used for anomaly detection and outlier identification.

5.It can be used for market segmentation and customer profiling.

Disadvantages of Cluster Analysis:

1.It can be sensitive to the choice of initial conditions and the number of clusters.

2.It can be sensitive to the presence of noise or outliers in the data. 

3.It can be difficult to interpret the results of the analysis if the clusters are not well-defined.

4.It can be computationally expensive for large datasets.

Types Of Data Used In Cluster Analysis -

Types Of Data Used In Cluster Analysis Are:

•Interval-Scaled variables

•Binary variables

•Nominal, Ordinal, and Ratio variables

•Variables of mixed types

1.Interval-Scaled Variables

Interval-scaled variables are continuous measurements of a roughly linear scale.

Typical examples include weight and height, latitude and longitude coordinates (e.g., when clustering houses), and weather temperature.

The measurement unit used can affect the clustering analysis. For example, changing measurement units from meters to inches for height, or from kilograms to pounds for weight, may lead to a very different clustering structure.

2.Binary Variables

A binary variable is a variable that can take only 2 values.

For example, generally, gender variables can take 2 variables male and female.

3.1.Nominal or Categorical Variables

A generalization of the binary variable in that it can take more than 2 states, e.g., red, yellow, blue, green.

Method 1: Simple matching

The dissimilarity between two objects i and j can be computed based on the simple matching.

Method 2: use a large number of binary variables

Creating a new binary variable for each of the M nominal states.

3.2.Ordinal Variables

An ordinal variable can be discrete or continuous.

In this order is important, e.g., rank.

It can be treated like interval-scaled 

3.3.Ratio-Scaled Intervals

Ratio-scaled variable: It is a positive measurement on a nonlinear scale, approximately at an exponential scale, such as Ae^Bt or A^e-Bt.

4.Variables Of Mixed Type  

A database may contain all the six types of variables

symmetric binary, asymmetric binary, nominal, ordinal, interval, and ratio.

And those combinedly called as mixed-type variables. 

Types of Data Structures

what types of data structures are widely used in cluster analysis.

We shall know the types of data that often occur in cluster analysis and how to preprocess them for such analysis. Suppose that a data set to be clustered contains n objects, which may represent persons, houses, documents, countries, and so on. 

Main memory-based clustering algorithms typically operate on either of the following two data structures.

Types of data structures in cluster analysis are 

•Data Matrix (or object by variable structure)

•Dissimilarity Matrix (or object by object structure)

1.Data Matrix

This represents n objects, such as persons, with p variables (also called measurements or attributes), such as age, height, weight, gender, race and so on. 

2.Dissimilarity Matrix

This stores a collection of proximities that are available for all pairs of n objects.