Heart-rate Response to Simulated Anxious Events
Development of kids’ friendly wearable device for children’s safety
SeungHee Lee* Masatoshi Hamanaka* Yoshiki Iwamoto* Dahyun Kim*** University of Tsukuba
1-1-1 Tennodai, Tsukuba, Japan, iwamoto, lee@kansei.tsukuba.ac.jp, hamanaka@iit.tsukuba.ac.jp** Graduate School, University of Tsukuba
1-1-1 Tennodai, Tsukuba, Japan ,kimda@kansei.tsukuba.ac.jp

Abstract: This study aims to know how and when small children between 1 to 6 years, feel anxiety
during their daily lives. Pre-school children are our target to be kept them from crimes and accidents
while they are taken care in the nurseries or kindergartens or on holidays by any responsible persons.
This is basic research for designing a wearable device for children’s safety. We made several simulated
anxious situations as movies and facial emotion images to show to kids in a set of room. We founddepends on the ages or personal experiences, children’s reactions were different and anxiety was shown
up differently.

Key words: Kids safety, anxiety, heart-rates, simulated events, sharing information.

1. Introduction
This study was set up as a basic research for developing a wearable device for children’s safety in a local area.
There are many of crimes or accidents targeted to little children in many countries recent days. Particularly under
6 year old children (kindergarten ages before primary school), they have little ability on verbal communication
with people even with their parents. And recently in increasing working mothers, they are apart from theirchildren during day time. Some of kindergartens in Japan or other countries, they serve a security camera in theclassrooms when children are in. Mothers want to know how their children are spending their time at thekindergarten but many of them don’t want to keep watching them or teachers without any interaction. We foundthis through a survey of answer sheets in 2005 about children’s safety [1]. Parents want to know what theirchildren think about daily events and any unconscious behaviors or anxiety.
The final goal of this study is to know how children react to anxious or dangerous events for designinga wearable device can detect children’s heart-rates and movements with wireless sensors. The device will offer
only in-front views when children feel anxious or big changes of movements or heart-rates detected from thesensors. This study aims to know when and how the children show anxiety through heart-rates by simulated
movies and facial emotion images. This study is to make sure the development of wearable device with functionsof detecting physiological data such as movements and voices of children to prevent them from any potential
possibilities of crimes and accidents.

12. Methods
2.1. Set of the experimental room
The experimental room was set up with a big screen (200x150cm) and a projection and ECG equipments. Thisroom was big as 5x5(m) and with Tadami floor to make people get rests or experiments at the university. It iseasy to concentrate to the movies in this small space. ECG equipments were set up behind the subjects’ seat not
to be seen by subjects. For younger aged children between 1-2 years, mothers could stay with them in the room
during the experiment. Children have two electric bandages on their chests, one on their chest and the otherbehind of their waist to be positioned across the heart (Fig.1).

2.2. Set of simulated images
Simulated events movies
To know the reactions of heart-rates from 1 to 6 year-old children,
it was not possible to make real situations to them. So, we had to
set up a series of simulated events as movies. 11 simulated
movies in total were prepared which can be divided into four
categories, such as, nature (storm, heavy rains), traffic (runningtrain, trucks), people (strangers, barking dog) and events (firework, jet coasters, top of the building etc) (Table1).
Figure1. Experimental room

And forrelieving their heart-beats occurred by the stimuli, we inserted

scenes of nature and their nurseries’ faces in between the stimulus movies.

Facial emotion simulations
For facial emotion simulations, we prepared slide images showing five basic emotional expressions on
unfamiliar faces of adults (surprise, anger, happiness, fear, sorrow: Unmasking the face by Paul Ekman1987)(Fig.2). Each facial emotion was played by 4 people (each two female and male professionals) for 17 seconds.

Table1.

Categories of simulated events movies

NatureStorm, wind, heavy rain

PeopleBarking dog, strangers

Traffic

Truck, train, motorbike

EventsFire work, jet coaster2surprise
Figure2.

anger

happinessfearsorrow

Facial Emotion (Unmasking the face, Ekman 1987)

2.3. Heart rate measuring
During the experiments, we recorded subjects’ heart-rates with Electrocardiogram (ECG). We measured it tocheck physiological change and we observed children’s behavior during the experiment. Experiment was takenfor 15 minutes in total. Instantaneous heart-rate was obtained from the ECG to calculate the change in heart-rate.
The electric bandage was obtained extra soft disposable ones not to be harmful for children’s skin. For children’
safety during the experiment, the study plan was reviewed by Committee of Ethics on Research program ofUniversity of Tsukuba 2007, 2009.

3. Results
3.1. ECG results
The heart-rates response to the movies was different between the age groups. We divided the 15 subjects into
three groups, one for 1~2 year, one for 3~4 year and the other for 5~6 year-old. Each group has 5 children. Whilethe 1~2 year-old subjects mainly showed decreases or no changes in heart rate for almost stimuli, and the 3~4year-old exhibited clear changes of reaction for each stimulus as we expected. One of the subjects in 1~2 year
notable exception appeared to the response to movies of their nursery school teachers; children of all age groups
tended to show decreases in heart-rate for teachers. An age-related difference was observed also for the responseto emotional expressions. Elderly children were more likely to show clear changes in heart rate than younger
children for each emotion. Thus, for both movies and facial images, elderly children tended to show a wider
range of responses between subjects. Interestingly, their behavioral responses during the experiment showed an
opposite tendency. When the images turned to negative emotions, such as sorrow or anger, younger children
often covered their eyes with their hands or turned around their faces to their parents while most of elder children
kept watching the given visual stimuli. Elderly children better accustomed to how to react to those emotion.

3.2. AnalysisSimulated Events movies
The data of ECG should be prepared by state of average of before the stimuli (Pre.) and state of average ofduring stimuli (Stimulus). We analyzed the data as change of heart rates come from the gap of each average(Stim.-Pre.). For Simulated events, three seconds before the stimulus (Pre.) adapted and the average of stimulus
was for 5 seconds, 2 seconds after the stimulus until 7 seconds.

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Facial Emotion images
Between the stimulus images, it has fade-in andout effects to change the slides, we had tocalculate 2 seconds of (Pre.) condition when thestimulus starts to show up (1sec) and aftershown up (1sec). For the average of time
viewing the images, 17 seconds was calculated
in facial emotion stimuli (Fig.3).
We

constructed

aninterface

tooverview the children’s faces, ECG data andstimuli at the same time (Fig.4) to analyze thedata easily.

Figure 3.

Stimulated Events (upper) and Facial Emotion (lower), gap of averages

Figure 4 Interface combining stimuli, subjects and heart rates
Stranger (up left)
Events (up right)

Anger (below left)
Fear (below right)

Figure 5

Different heart rates depending on children’s ages.

44. Development of the wearable device
The concept of device named “Omusbi [4]” means a rice ball which mothers make for their children in Japan.
The name of device hopes to connect children, parents and people in the local network to help children’s safety.
The final device is now developed as an experimental prototype for children toknow how long they can keep wearing the device (weight), how gentle they use thedevice (treatment), and which color or designs would be selected by them.
The positioning of heart-rate bandage on the chest was also tested before
we set up the device. We tested every point near the heart where can get the clearer
signals (Fig.6). To attach the heart-rate sensors, it should be needed at least 50mm
separated space between two spots.
Finally, in the device the heart-rates, movements, and voice recorder,Fig.6 Hear rate Positioning

camera with with fisheye lens is adopted and all the sensors are controlled by micro computer to store and send
the data. It is also under going to obtain technical patent copy rights.

5. Conclusion
This study revealed that, for both simulated movies and facial emotion, each age group exhibited different
responses in heart-rates and behavior at the same time. The age-related changes in physiological and behavioral
responses of children probably reflect the amount and variety of experiences that they have been acquired. The
results suggest that the heart rates could be a useful tool to detect anxiety of children who cannot verbally
express their feelings to the parents. We conclude that applying the sensors not only heart-rates but also
behavioral movements (3D accelerator) would be easier to know children’s conditions in danger. For the final
step to build the device more efficiently, this result would be the first step to confirm how children react byphysiological responses.

6. Acknowledgement
This is a research to develop a wearable device for kids’ safety. Our goal to develop a wearable device is acontracted project with SCOPE (Strategic Information and Communications R&D Promotion Program), Ministryof Internal Affairs and Communications, JAPAN7. References[1]Seunghee Lee(2007), “Kansei Ubiquitous Interaction for Kid’s Safety”, Proceedings of the 3rd Spring
Conference of Japan Society of Kansei Engineering, P.C24[2]Paul Ekman & Wallace V. Friesen(1987), “Unmasking the face”, translated by Tsutomu Kudo, Malor Books[3]Allen M. Schneider (1995), “Elements of Physiological psychology”, Macgraw-Hill College[4]SeungHee Lee (2010), “Development of Wearable Device by Kid’s Friendly Design for Kid’s Safety”, HCI2010(in printing)[5] Hiroshi Kanasugi & Ryosuke Shibasaki (2004), “Measurement and Analysis of Humand Behavior using
Wearable Sensors”, Proceedings of the 25th Asian Conference on Remote Sensing, Vol.2, pp.1218-1223[6]Kazuya Kousaka, Kazuhiro Imaki, Kazuhiro Imaki, Hirohide Haga and Shigeo Kaneda., “Classification ofChildren's Group Activity from acceleration data by using Wavelet transformation”, Information Processing
5Society of Japan SIG Technical Notes, Vol. 2009, No.13, pp. 1-8, 2009 (in Japanese).
[7] Kazushige Ouchi, Takuji Suzuki, Miwako Doi, “LifeMinder : A Wearable Healthcare Support System with
Timely Instruction Based on the User's Context”, IEICE transactions on information and systems, E87-D(6),pp.1361-1369, 2004.
[8] Ali Benkhalil, Stanley Ipson and William Booth, “Real-time video surveillance system using a field
programmable gate array”, International Journal of Imaging Systems and Technology,Vol. 11, No. 2, PP.130137, 2000.

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