Table 1 Dictionary of notations.

From: A fault diagnosis method for wireless sensor network nodes based on a belief rule base with adaptive attribute weights

Notation

Meaning

\(R_{k}\)

The \(k{\text{th}}\) belief rule

\(W\)

Number of input attributes in the fault diagnosis model

\(a_{1} ,...,a_{W}\)

Total \(W\) input attributes

\({\text{F}}_{1} ,...,{\text{F}}_{W}\)

Reference values corresponding to the \(W\) input attributes

\(H_{1} ,...,H_{N}\)

\(N\) possible troubleshooting results

\(D_{1} ,...,D_{N}\)

The belief degree associated with each outcome under the \(k{\text{th}}\) belief rule

\(\theta_{k}\)

Rule weights for the \(k{\text{th}}\) belief rule

\(\updelta _{1}^{{}} {,}...\updelta _{w}^{{}}\)

Attribute weights of the \({\text{W}}\) input attributes

\({\text{a}}_{1} \left( t \right){\text{,a}}_{2} \left( t \right)...,{\text{a}}_{w} \left( t \right)\)

Data features of \({\text{W}}\) attributes extracted in a time interval

\(\mu ()\)

Computational function for extracting features from the raw sensor data obtained from WSN

\(\Lambda\)

Parameters involved in the process of extracting data features

\(X\)

Raw data collected by the sensor over a period of time interval

\(t\)

At a certain point in the time interval

\(\delta_{{\text{j}}}^{{\text{i}}}\)

Adaptive attribute weights (BRB-AAW)

\(K\)

The total number of belief rules in the model

\(\Xi\)

Expert knowledge for initializing adaptive attribute weights

\(g()\)

Calculation function of adaptive attribute weights

\(S\left( t \right)\)

Predictive fault states for troubleshooting systems

\(\tau\)

Other parameters involved in the fault result diagnosis function

\(f()\)

Calculation function of fault diagnosis results

\(\tau_{{{\text{best}}}}\)

Optimized parameters after optimization algorithm

\(\beta\)

Parameters in the optimization algorithm

\(h()\)

Parameter optimization algorithm

\(Q\)

A time point of the node being diagnosed

\(T\)

Length of time

\(\overline{{\text{a}}}\)

The average of the collected data features over the specified time interval

\(\upalpha ^{4}\)

The standard deviation of the collected data features over the specified Time interval

\(\uprho _{{\text{i}}}^{{\text{j}}}\)

The degree of matching of the \(i{\text{th}}\) attribute in the \(j{\text{th}}\) reference value

\({\text{F}}_{{\text{i}}}^{{\text{k}}}\)

the \({\text{ith}}\) attribute's \(k{\text{th}}\) reference value

\(\rho_{{\text{k}}}^{{\text{i}}}\)

the match of the \(i{\text{th}}\) attribute in the \(k{\text{th}}\) belief rule

θi

Weight of the belief rule \(i\)

\(\mho_{i}\)

The activation weight of the \(i{\text{th}}\) belief rule

N

The framework for identifying fault diagnosis models includes \(N\) levels

\(D_{j,i}\)

Belief degree of the \(j{\text{th}}\) fault diagnosis result in the \(i{\text{th}}\) rule

\(p\left( {H_{i} } \right)\)

The utility of the \(i{\text{th}}\) fault diagnosis

g

The \(g{\text{th}}\) generation optimization algorithm iteration

\(\tau_{{\text{i}}}^{{{\text{g + }}1}}\)

The optimized parameters of the \(i{\text{th}}\) group in the \((g + 1){\text{th}}\) generation

\(\tau_{{{\text{best}}}}^{{\text{g}}}\)

Average value of optimized parameters in the \(g{\text{th}}\) generation

\(\varepsilon_{{}}^{{\text{g}}}\)

Step size of the \(g{\text{th}}\) generation

\({\mathbb{R}}\)

Normal distribution

\(C_{{}}^{{\text{g}}}\)

Covariance matrix of the \(g{\text{th}}\) generation

\(\lambda\)

Number of offspring iterated

\(E_{{\text{e}}}\)

Parameter vector

\({\text{n}}_{{\text{e}}}\)

Restricted variables in \(\tau_{{\text{i}}}^{{\text{g + 1}}}\)

\(j\)

The number of restricted variables in \(\tau_{{\text{i}}}^{{\text{g + 1}}}\)

\({\text{h}}_{{\text{i}}}\)

Weighting factor

\(\tau_{{{\text{i:}}\lambda }}^{{\text{g + 1}}}\)

The \(i{\text{th}}\) solution in the \(\left( {g + 1} \right){\text{th}}\) generation of the total \(\lambda\) group of optimization parameters

\(\sigma\)

Number of solutions in the offspring