Real Time Data Processing Techniques

Various Signal Processing Techniques are available for analysis of real time data relative to reference data:

 

Data Cluster method – This involves recording the characteristics of a parameter of a subsystem under different simulated conditions and then using this as a reference to validate the real time data. This method is different from template matching, since it not entirely based on matching the plotted characteristics.

 

Template matching – Entails comparing complete data sets with pre-recorded examples of data resulting from known fault conditions. The method can be used effectively in some circumstances, provided a representation of the data that produces good discrimination between pattern classes can be made. However, this requires a substantial amount of experimentation with different transformations of the data sets to find such distinctions, and would be a computationally intensive process.

 

Statistical and decision theoretic methods – Matches are made based on statistical features of the signal. For example, the mean and peak-to-peak value are evaluated for each vector, and plotted in feature space, whereby different patterns are distinguishable because they form clusters for each class that are located apart from the fully functioning case.

 

Structural or syntactic methods – Involves deconstructing a pattern or vector into structural components, to enable comparisons to be made on more simple, sub-segments of data rather than a complete vector. Mathematically, these methods are similar to fractal-based compression routines.

 

Principles of Train working and need for Signalling

All over the world Railway transportation is increasingly used, as this mode of transport is more energy efficient and environmentally friendly than road transportation. Trains move on steel rail tracks and wheels of the railway vehicle are also flanged Steel wheels. Hence least friction occurs at the point of contact between the track & wheels. Therefore trains carry more loads resulting in higher traffic capacity since trains move on specific tracks called rails, their path is to be fully guided and there is no arrangement of steering. Clear of obstruction as available with road transportation, so there is a need to provide control on the movement of trains in the form of Railway signals which indicate to the drivers to stop or move and also the speed at which they can pass a signal. Since the load carried by the trains and the speed which the trains can attain are high, they need more braking distance before coming to the stop from full speed. Without signal to be available on the route to constantly guide the driver accidents will take place due to collisions.

 

There are basically two purposes achieved by railway signalling.

1. To safety receive and dispatch trains at a station.

2. To control the movements of trains from one station to another after ensuring that the track on which this train will move to reach the next station is free from movement of another train either in the same or opposite direction. This Control is called block working. Preventing the movement from opposite direction is necessary in single line track as movements in both directions will be on the same track.

 

Apart from meeting the basic requirement of necessary safety in train operation, modern railway signalling plays an important role in determining the capacity of a section .The capacity decides the number of trains that can run on a single day. By proper signalling the capacity can be increased to a considerable extent without resorting to costlier alternatives.