**4. Walking stability analysis**

374 Health Management – Different Approaches and Solutions

<sup>2</sup> ( ) ( 1, 2)

2. Comparing the acceleration between the computing data and accelerometer data by

Data reduction techniques can be used to obtain a reduced representation of the data while minimizing the loss of information content. To obtain a reduced representation of the data set, such as speed, average span, frequency, and so on, data reduction techniques can be applied, for examples, aggregation operations and conception hierarchy generation. We

(7)

2 1 2

*x xx*

*i ii*

*t y yy a y i N t z zz*

<sup>2</sup> ( )

*i*

*a x*

*i*

*i*

*a z*

Fig. 16. The result of aligning motion data and acceleration data

propose a hierarchical structure shown in Fig. 17.

Person Data

Fig. 17. The hierarchical structure of walking data

Motion Data

Unit Data Model Data

Feature Data

Footprint Walking Cycle Statistics Feature

> Acceleration Data

Stability Data

> Person Data

Symmetry Data

……

……

……

Motion Data

Unit Data Model Data

Feature Data Footprint Walking Cycle Statistics Feature

> Acceleration Data

**3.5 Data reduction** 

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minimum of relativity. The result of aligning is shown in Fig. 16.

2 1 2

*i ii*

2 1 2

*i ii*

*t*

Although there is now a wealth of literature pertaining to the maintenance of stability when standing, there is a relative paucity of information regarding the biomechanics and physiology of walking stability. Various models are currently in development, but a unified model of walking stability does not exist yet. Unlike standing, the balance of walking is a kind of dynamic balance (Menz, 2000).

Standard deviation is used to define the variability or randomness of the walking pattern. Less the amount of variability means better neuromuscular control and walking stability. We extract a set of hierarchical features from FL model, such as walking cycle features, footprint features.

### **4.1 Footprint stability**

Footprint analysis is a typical method of walking research as shown in Fig. 18.

Fig. 18. Features of footprint stability
