Bayesian Network Anomaly Detection

  • Bayesian networks model the probabilistic relationships between variables. Anomalies can be detected by identifying instances where observed data significantly deviates from the expected probabilities.
  • The bnlearn package is commonly used for Bayesian network modeling.

R




# Load the package
install.packages("bnlearn")
library(bnlearn)
 
# Generate some example data
set.seed(123)
data <- data.frame(
  A = rnorm(100),
  B = rnorm(100),
  C = rnorm(100)
)
 
# Define the structure of the Bayesian network
# For example, A and B are parents of C
network_structure <- model2network("[A][B][C|A:B]")
 
# Build a Bayesian network
bn_model <- bn.fit(network_structure, data)
print(bn_model)


Output:

  Bayesian network parameters
Parameters of node A (Gaussian distribution)
Conditional density: A
Coefficients:
(Intercept)
0.09040591
Standard deviation of the residuals: 0.9128159
Parameters of node B (Gaussian distribution)
Conditional density: B
Coefficients:
(Intercept)
-0.1075468
Standard deviation of the residuals: 0.9669866
Parameters of node C (Gaussian distribution)
Conditional density: C | A + B
Coefficients:
(Intercept) A B
0.13506543 -0.13317153 0.02381129
Standard deviation of the residuals: 0.9512979

Anomaly Detection Using R

Anomaly detection is a critical aspect of data analysis, allowing us to identify unusual patterns, outliers, or abnormalities within datasets. It plays a pivotal role across various domains such as finance, cybersecurity, healthcare, and more.

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