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    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>A Smart Walking Navigation System based on Perceived Exertion</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Panote Siriaraya</string-name>
          <email>spanote@gmail.com</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Kodo Maeda</string-name>
          <email>g1445232@cc.kyoto-su.ac.jp</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Yusuke Nakaoka</string-name>
          <email>g1444936@cc.kyoto-su.ac.jp</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Yukiko Kawai</string-name>
          <email>kawai@cc.kyoto-su.ac.jp</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Shinsuke Nakajima</string-name>
          <email>nakajima@cse.kyoto-su.ac.jp</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Kyoto Sangyo University</institution>
          ,
          <addr-line>Kyoto</addr-line>
          ,
          <country country="JP">Japan</country>
        </aff>
      </contrib-group>
      <abstract>
        <p>In recent years, the growing trend of personal well-being has led an increasing number of people to engage in walking related activities to improve their physical health. As such, it is becoming increasingly important to develop walking navigation systems which are able to effectively support such activities. The conventional walking navigation systems found in modern smart phone devices usually recommends the shortest route to a destination and are not aimed at facilitating health promoting walking activities. Therefore, in this paper, we propose a novel walking navigation system which takes into consideration the rate of perceived exertion (based on the walking distance, geographical elevation and heart rate data) and the avoidance of dangerous locations and the possibility of passing through highly rated scenic locations (based on social network data from twitter) when recommending a route. Finally, we describe the results of a feasibility experiment study carried out to test the routes in the system.</p>
      </abstract>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>-</title>
      <p>INTRODUCTION
The recent growing trend of personal well-being has led an
increasing number of people to engage in walking related
activities for a variety of health related purposes, such as to
reduce weight and maintain their physical fitness. Various
©2018. Copyright for the individual papers remains with the authors.
Copying permitted for private and academic purposes.</p>
      <p>
        WII’18, March 11, 2018, Tokyo, Japan
government policies and initiatives (such as [
        <xref ref-type="bibr" rid="ref9">9</xref>
        ]) have been put
in place to help raise awareness about the importance of
physical exercise. However, even though people are aware of the
importance of physical exercise, it is difficult for them to
engage and continue in such activities for a prolonged period of
time. As such, there is an emerging need for the development
of walking navigation systems which are able to effectively
support health promoting walking activities.
      </p>
      <p>Despite walking navigation systems becoming more
commonplace in modern smart phone devices, the conventional
navigation systems were not created with the goal of facilitating
health related walking activities and generally recommends
the shortest route to a selected destination. In this paper, we
propose a smart walking navigation system which is aimed
especially at supporting health related walking activities. To
create a walking route which is effective, enjoyable and safe
for users, we describe how an appropriate perceived exertion
load could be determined based on information such as the
walking duration, geographical inclination and heart rate and
describe how the system could help users avoid accident prone
locations and suggest pleasurable walking routes which passes
through scenic locations by using social network data from
twitter.</p>
      <p>The appropriate perceived exertion load refers to an exertion
load which is appropriate for a user based on their physical
characteristics and their purpose of exercise. Overall, the
walking load of each route is calculated by combining data from
the measurement of the level of inclination and distance within
the route with heart rate data. To help avoid dangerous routes,
data from geo-tagged twitters are also obtained and analyzed.
For instances, various phrases which denote a dangerous
conditions, such as "it’s dangerous", "I’m afraid" or "It’s dark" are
collected and used to estimate the level of danger on a route.
In addition, to facilitate a more enjoyable walking experience,
data which could indicate the presence of appropriate resting
locations is also taken into consideration. This includes data
which describes locations with good panoramic views or
seasonal sightseeing locations (for cherry blossom and autumn
leaf viewing etc.). Similar to how we obtained information
about dangerous routes, the system collects data about
appropriate resting locations from geo-tagged tweets. Highly
evaluated scenic locations are identified and considered in the
route recommendation.</p>
      <p>Overall, this paper presents a smart walking navigation system
which recommends a route based on the rate of perceived
exertion and the possibility of passing through highly rated scenic
locations and avoiding dangerous locations. In this paper, we
discuss how such a navigation system could be implemented.
Afterwards, we describe a feasibility experiment carried out
to test the routes in the proposed system.</p>
      <p>
        RELATED RESEARCH
Route recommendation systems have been developed and used
for a variety of purposes such as in tourism and health care
(see [
        <xref ref-type="bibr" rid="ref12">12</xref>
        ] [
        <xref ref-type="bibr" rid="ref14">14</xref>
        ] [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ] etc.). For those aimed at supporting walking
related activities, previous research tend to focus on issues
related to health and safety (such as providing a walking route
which can effectively improve the health of a user during
exercise activities) and issues related to improving the underlining
walking experience (such as providing a walking route which
is aesthetically pleasurable).
      </p>
      <p>
        Examples of walking support and route recommendation
systems which focus on health and safety include one system
devised by Takaishi et al [
        <xref ref-type="bibr" rid="ref13">13</xref>
        ] which aimed to provide older
users with a personalized walking plan by combining data
from a GPS and a heart rate monitoring device. This was
done to provide better walking instructions for older people
looking to go walking as a way to exercise and improve their
health. However, the adoption and execution of this
"walking plan" is still reliant on the motivation of the users and
the system does not automatically change or recommend the
route in real time. In terms of safety, Kim et al.[
        <xref ref-type="bibr" rid="ref5">5</xref>
        ] proposed
a system which helps users avoid dangerous routes by using
data from geo-tagged tweets. Another study proposed a route
recommendation system which recommends a walking route
based on the number of calories which users wish to lose [
        <xref ref-type="bibr" rid="ref14">14</xref>
        ].
The overall aim of the system is to provide continuous support
for users who wish to take daily walks for exercise, with the
system attempting to recommend different routes each day to
prevent boredom. To help reduce stress during walking related
activities, research carried out by Kitabayashi et al [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ] used
biological data such as the user’s heart rate and data related
to the walking environment to analyze and estimate the level
of stress. The main aim was to provide a walking path which
is physically less stressful, especially for populations such as
older people. Overall, even though such systems are helpful
in recommending a route which is appropriate as a means
of exercise, there is still the problem of motivating users to
participate in the walking activity. To better motivate users,
we believe that it would also be advantageous to also consider
information from the environment within the walking route
as well (such as potential scenic locations within the walking
route).
      </p>
      <p>
        Various systems have also been developed to help provide
users with a more pleasurable walking experience. For
instance, one study proposed a route recommendation system
which is not based on the shortest distance, but on the potential
enjoyment quality within the route [
        <xref ref-type="bibr" rid="ref11">11</xref>
        ]. Abdallah et al [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ] in
the meanwhile, proposed a route recommendation system for
those seeking to explore a city. The aim was to provide users
with recommendations of routes which contain interesting
elements (scenic views etc.) by analyzing geo-tagged photos
from photosharing sites such as Flickr. Other researchers have
also proposed a walking support system which allows users to
share scenic locations within a walking course with others[
        <xref ref-type="bibr" rid="ref8">8</xref>
        ].
Although such systems are helpful in providing a motivating
walking route for users, they generally do not include
biological data from users in their recommendation and therefore
tend not to take into account the physical characteristics of
users (such as their physical ability or exertion) which could
also significantly influence the walking experience.
A SMART WALKING NAVIGATION SYSTEM BASED ON
THE RATE OF PERCEIVED EXERTION
Overview
In this paper, we propose a Smart Walking Navigation
System which recommends a route based on the user and path
characteristics, taking into account the rate of perceived
exertion and the possibility of avoiding dangerous locations and
the ability to pass through highly rated scenic locations. An
overview of the system is shown in Figure 1. Users first start
by inputing information about their age, gender, resting heart
rate and desired walking duration. Based on this, the system
would then determine an appropriate walking distance. Within
this walking distance area, the system would obtain data about
the inclination level, the heart rate of previous pedestrians, the
presence of potentially dangerous locations (such as narrow
paths, heavy traffic and train crossings) and locations which
are scenic or popular with tourists. Based on this information,
several walking routes would then be recommend to the user.
In the following section, we provide more details about the
data used in the recommendation of the routes and discuss the
method which can be used to obtain the data.
      </p>
      <p>
        The data
heart rate data
To help determine the appropriate exertion load, the user’s
target heart rate is calculated [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ]. The equation used to calculate
the target heart rate is as follows:
thri = (220 - agei - rhri) * tc + rhri
In the equation, thr refers to the target heart rate , rhr refers to
the resting heart rate and tc refers to the target coefficient.
The level of inclination
Geospatial elevation data from the the Geospatial Information
Authority of Japan was used to calculate the level of inclination
for a specific location [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ]. The inclination data was acquired
by using elevation data from a 5 meter grid interval. The open
source software QGIS [
        <xref ref-type="bibr" rid="ref10">10</xref>
        ] was used to create a road network
containing the latitude, longitude and elevation information.
Information about scenic locations, word of mouth reviews and
dangerous locations
Information about scenic locations in the area could be
obtained from geo-tagged tweets combined with data from
sightseeing guide websites. For instance, tweets with phrases such
as "the cherry blossoms are beautiful" and "The night view
is pretty" could provide information about possible scenic
locations in the area. A key advantage of using geo-tagged
tweets is that it allows us to obtain information about not only
the popular tourist-based scenic locations in the area, but also
allows us to identify less well known ones as well. In addition,
using geo-tagged tweets allow the system to obtain scenic
location information which is more context specific and up-to date
(such as flower viewing spots which only appear during
certain seasons or night viewing spots which are most beautiful
during night time). Information about potentially dangerous
routes is obtained in a similar manner, by identifying words
and phrases such as "dangerous" and "scary" from geo-tagged
tweets.
      </p>
      <p>
        Implementation of the walking route recommendation
system
Estimating the walking speed based on age and gender
When using the system, the users would input how long they
wish to walk (their desired walking duration). To be able to
accurately determine the length of the recommended route, it
is necessary to estimate the potential walking speed of each
user. Information about the age and gender of the users is used
to help determine the walking speed. The average walking
speed of people when they walk around indeterminately could
be found at [
        <xref ref-type="bibr" rid="ref16">16</xref>
        ]. Based on this data, the appropriate walking
distance (i.e. the desired length of the route) is calculated.
Obtaining map and elevation data
The open source software QGIS was used to obtain Open
street map (OSM) data [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ] as well as data about the elevation,
latitude and longtitude.The data obtained in this study is
centered around the city of Kyoto, Japan at the latitude-longitude
coordinate of 6,662. Every OSM data point was given
elevation, longitude and latitude data from QGIS. The length of
the road was calculated using differences in longitude/latitude.
The inclination between two points was calculated based on
the difference in elevation.
      </p>
      <p>Route recommendation through Dijkstra’s algorithm
Traditional walking navigation systems calculate the shortest
route between the starting point and target destination using
Dijkstra’s algorithm. In this study, in addition to the walking
distance, we would also take into account the perceived rate of
exertion, the presence of potentially dangerous areas as well
as the availability of scenic locations.</p>
      <p>Initially, the proposed system randomly selects multiple
candidate sites based on the target walking distance. The inclination
data and information about possible dangerous and scenic
locations are obtained for the points on the shortest route to the
candidate sites (calculated using Dijkstra’s algorithm).
Afterwards, the system recommends routes by considering the
perceived exertion load and the possibility of passing through
safe and scenic locations.</p>
      <p>For example, if a walking distance of 800 meters is required,
multiple points from within the edge of the approximately 800
meter circular radius range are selected and the shortest route
from the starting spot to these points are calculated using the
Dijkstra’s algorithm. When the desired walking distance is
reached, the points are then made into candidate sites. See
Figure 2 for an example of the routes proposed by the system.
After the candidate sites have been obtained, data about the
inclination would be acquired for the points on the routes to
the candidate sites and used to investigate the physical exertion
load based on the targeted heart rate of the user. In the future,
the heart rate data would be used to help predict the level
of perceived exertion on different routes. Geo-tagged tweets
were also obtained for the points on the route. In regards to the
tweets, in the current system, the number of tweets were used
as an indicator of the popularity of the location, regardless of
whether they were positive or negative in nature. In the future,
we would look into using sentiment analysis to separate the
negative locations from the positive ones. Overall, both data
related to the inclination and the tweets would be displayed
for the routes to the candidate sites.</p>
      <p>To test the feasibility of the currently proposed system, an
experiment study was carried out. The main aim was to
determine whether the perceived exertion load of the user is
influenced by the inclination within the route and whether
geo-tagged tweets could be a good indicator of the enjoyment
within the route.</p>
      <p>FEASIBILITY STUDY OF THE ROUTE RECOMMENDATION
SYSTEM
An experiment study was carried out to test the feasibility of
the proposed method. Figure 2, shows an example of 8
different waking navigation routes recommended by the method
proposed in the paper. The targeted walking distance (from
the start location "S" to the points G1 to G8) is around 800m.</p>
      <p>To test the feasibility of the recommendation method, three
participants were asked to walk through the routes
recommended by the system. Overall, the routes to the destinations
G2 and G4 were selected as they had a large difference in
tweet numbers but were similar in terms of changes to the
level of inclination. In addition,the routes to the destinations
G1 and G3 were also selected as they were similar in terms of
tweet numbers but had large difference in inclination change.
Participants wore a smart watch which measured their heart
rate as they walked through the route. In addition,
participants were also asked to rate their experience while walking
the route. They were asked to rate three factors 1) how easy
they felt the route was 2) how enjoyable was the route and
3) whether they would like to walk on the route again on a 7
point Likert scale.</p>
      <p>The results are shown in table 3. As expected, the average
heart rate of participants increased substantially for routes
with high upper elevation (G1). In addition, participants felt
it was easier to walk on routes with a low combined upper
elevation (G2 and G3) than those with a high combined upper
elevation (G1 and G4). Thus, the results suggest that the level
of inclination change within a route could be a good indicator
of the perceived exertion of users on that route.</p>
      <p>
        The influence of the number of tweets on user enjoyment and
motivation was less clear. There seems to be a trend in that
for routes with a high number of tweets, the reported level of
enjoyment and motivation seems to be higher than routes with
a lower number of tweets (i.e. G1 being higher than G2 and
G3 and G4 being higher than G3). Overall, the system could
be further refined by using methods such as sentiment analysis
to analyze the tweets in more detail, using a method similar to
[
        <xref ref-type="bibr" rid="ref15">15</xref>
        ] to incorporate the tweets to a route area.
      </p>
      <p>Route</p>
      <p>G1
G2
G3
G4
SUMMARY
In this paper, we have proposed a smart walking navigation
system which recommends a walking route that takes into
account the perceived exertion load (based on the walking
duration, heart rate and inclination etc.), the possibility of
avoiding dangerous locations and the ability to pass through
highly rated scenic and popular locations. The overall aim
of the system is to provide a walking experience which is
enjoyable, safe and beneficial to the physical health of the user.
We have described how such a system could be implemented.
In addition, we have provided the results of an experiment
study carried out to test the feasibility of the proposed method,
showing how the routes suggested by the system could
influence the level of perceived exertion for users. In the future, we
aim to refine the proposed method by using sentiment analysis
to analyze the tweets and determine the scenic and dangerous
locations within the route. In addition, we would also
examine a more personalized approach towards recommending the
appropriate walking distance for each user based on their
physical abilities and health conditions (i.e. by using information
from smart watches which can collect health related data to
infer the physical ability of users etc.).</p>
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