Using Passive Sensing to Estimate Relative Energy Expenditure for Eldercare Monitoring

Shuang Wang, Marjorie Skubic, Yingnan Zhu, Colleen Galambos, Shuang Wang, Marjorie Skubic, Yingnan Zhu, Colleen Galambos

Abstract

This paper describes ongoing work in analyzing sensor data logged in the homes of seniors. An estimation of relative energy expenditure is computed using motion density from passive infrared motion sensors mounted in the environment. We introduce a new algorithm for detecting visitors in the home using motion sensor data and a set of fuzzy rules. The visitor algorithm, as well as a previous algorithm for identifying time-away-from-home (TAFH), are used to filter the logged motion sensor data. Thus, the energy expenditure estimate uses data collected only when the resident is home alone. Case studies are included from TigerPlace, an Aging in Place community, to illustrate how the relative energy expenditure estimate can be used to track health conditions over time.

Keywords: eldercare monitoring; energy expenditure; fuzzy logic; motion density map; visitor recognition.

Figures

Figure 1
Figure 1
An example of a motion density map
Figure 2
Figure 2
The floor plan of an apartment showing sensor placement
Figure 3
Figure 3
Membership functions for the duration between visitor markers
Figure 4
Figure 4
Membership functions of the density ratio
Figure 5
Figure 5
An example of a motion density map (top) and the corresponding visitor events (bottom). White areas represent the visitor events identified with the visitor recognition algorithm.
Figure 6
Figure 6
Case study #1: weekly relative energy expenditure estimates for 03/01/2007~12/01/2007. The area highlighted in green shows the corresponding month for Figure 7. The area highlighted in red shows the corresponding month for Figure 8.
Figure 7
Figure 7
Activity density map (top) and visitor map (bottom) for case #1 July 2007
Figure 8
Figure 8
Activity density map (top) and visitor map (bottom) for case #1 September 2007
Figure 9
Figure 9
Case study #2: weekly relative energy expenditure estimates for 12/01/2008~03/01/2010. The area highlighted in green shows the corresponding month for Figure 10. The area highlighted in red shows the corresponding month for Figure 11.
Figure 10
Figure 10
Activity density map (top) and visitor map (bottom) for case #2 December 2008
Figure 11
Figure 11
Activity density map (top) and visitor map (bottom) for case #2 Feburary 2010

Source: PubMed

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