## 4 Dataset Description and Establishment
### Data Description  
In the hoisting system, the states of BTRs basically include normal, disproportional spacing, twisted rope, defect, and broken rope. The disproportional spacing is caused by unstable factors in the hoisting system, such as mechanical vibration, wind-induced vibration, etc., which is the precondition of twisted rope. The twisted rope fault occurs when the hoisting system is very unstable. In this paper, the collision contact of the two ropes is also classified as a twisted rope-type fault. The twisted rope-type fault is a serious fault that causes the instability in the hoisting system and produces broken rope or downtime, so it should be avoided. Defects include wear, broken wire, broken strand, and rust, among which, a broken strand, the precondition of a broken rope, is the most serious defect. Because the broken rope directly leads to the instability of the hoisting system or even accidents, we should try to avoid it. The measure of setting separate woods (using wood to separate each tail rope) has been adopted in order to prevent the collision of the BTRs, but the separate woods tend to damage the BTRs by scratching or pulling, which aggravates the wear and failure of the BTRs. The tail rope is in a state of free overhanging in the shaft, is subjected to random vibrations and external excitation, and its attitude is difficult to estimate. Therefore, according to the actual production situation, we use the empirical method to build up the BTRs' state dataset with the whole feature space as far as possible. The image dataset in this paper is made up of five typical feature states, namely, normal (a), disproportional spacing (b), twisted rope (c), broken strand (d) and broken rope (e), as shown in Figure 5.  
It should be noted that the distance of normal (a) here is defined as being greater than \(3/4\) of the normal distance (the distance between the tail ropes under stationary state). Disproportional spacing (b) is defined as a distance less than \(1/2\) of the normal distance between the two ropes. Twisted rope (c) is defined as a variety of forms in which two ropes get entangled. Broken strand (d) is divided into three categories, including broken strand of the left rope (d1), the right rope (d2), and double ropes (d3). Broken rope (e) is classified into three categories, including left broken rope (e1), right broken rope (e2), and double broken ropes (e3). As shown in Figure 5, we assume the normal distance between the tail ropes is \(D\), and the view of the image taken by the camera is \(L\) long and \(W\) wide, such that the following can be obtained: \(L>d_{1}>3/4D\), \(0<d_{2}<1/2D\), \(d_{3}=0\), \(0<h_{1}\leq W\), and \(0<h_{2}\leq W\). Therefore, the dataset has nine characteristics (i.e., a, b, c, d1, d2, d3, e1, e2, e3). When different faults are diagnosed, an early warning is carried out according to the different levels (Level 1: normal state is not warned; Level 2: when the distance is not uniform, a reminder is given regarding the deceleration operation but no warning is given; Level 3: overhaul warning when there is a broken strand; Level 4: a brake signal is immediately sent out when there is a twisted or broken rope). It is important to note that in order to distinguish the two characteristic states of normal and disproportional spacing, we define these spacings as being greater than \(3/4\) and less than \(1/2\) of the normal distance, respectively, and it needs to be observed when the spacing is between \(1/2\) and \(3/4\) of the normal \begin{table}
\begin{tabular}{c c} \hline
**Hardware Environment** & **Software Environment** \\ \hline CPU: Intel Core i5-6200U 2.40 GHz & System: Windows 10, \(\times\)64 \\ Memory: 8.00 GB & Development tool: Keras (Theano) \\ \hline \end{tabular}
\end{table} 
Table 2: The experimental environment. spacing (because the identification results may be normal or disproportional spacing).