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  <front>
    <journal-meta>
      <journal-title-group>
        <journal-title>Ren, K.; Karlsson, J.; Liuska, M.; Hartikainen, M.; Hansen, I.; Jørgensen, G.H. A Sensor-Fusion-
System for Tracking Sheep Location and Behaviour. Int J Distrib Sens Netw</journal-title>
      </journal-title-group>
    </journal-meta>
    <article-meta>
      <article-id pub-id-type="doi">10.1177/1550147720921776</article-id>
      <title-group>
        <article-title>iRunMon: A real-time ruminant monitor⋆</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Pedro Gonçalves</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>William Xavier</string-name>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Gustavo Corrente</string-name>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Instituto de Telecomunicações and Escola Superior de Tecnologia e Gestão de Águeda, Universidade de Aveiro</institution>
          ,
          <addr-line>Campus Universitário de Santiago P-3810-193, Aveiro</addr-line>
          ,
          <country country="PT">Portugal</country>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>iFarmTec and Wiseware, Zona Industrial da Mota</institution>
          ,
          <addr-line>Rua 12, Lote 51, Fração E, 3830-527 Gafanha da Encarnação</addr-line>
          ,
          <country country="PT">Portugal</country>
        </aff>
      </contrib-group>
      <pub-date>
        <year>2020</year>
      </pub-date>
      <volume>16</volume>
      <fpage>17</fpage>
      <lpage>20</lpage>
      <abstract>
        <p>Present paper presents a real-time animal monitoring solution envisaged for ruminants. The complete solution includes a wearable collar enabled with inertial sensors and a thermometer, a sensor gathering gateway that generates alarms and interfaces with a cloud hosted application that implements system analytics, and video recording tools that allow the supervision of telemetry data. System operation supports a triple mode: it operates in a learning mode where it gathers sensor data, an enriched version integrated with video recording information to enable learning data supervision, and a monitoring mode where the wearable system autonomously classifies animal behavior.</p>
      </abstract>
      <kwd-group>
        <kwd>eol&gt;Ruminant monitoring</kwd>
        <kwd>wearable sensor</kwd>
        <kwd>accelerometry</kwd>
        <kwd>behavior</kwd>
        <kwd>activity</kwd>
        <kwd>calving detection 1</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>1. Introduction</title>
      <p>
        Animal monitoring [16][
        <xref ref-type="bibr" rid="ref3">3</xref>
        ], has been attracting immense attention, both from academia and from
the industrial sector, due to its promising impact on Precision Livestock Farming and on animal
wellbeing, avoiding the cost and the errors associated with human monitoring. Inertial sensors by its
turn have been validated as a viable and economical way to monitor animal behaviors and have been
used to electronically analyzing what behaviors the animal performed during the day [
        <xref ref-type="bibr" rid="ref1 ref2">1,2</xref>
        ];
monitoring animal activity [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ], which allows the identification of disturbing events and to infer
energy consumption; or even in the detection of events related to animal health [
        <xref ref-type="bibr" rid="ref4 ref5">4,5</xref>
        ], such as
detection of parturition [
        <xref ref-type="bibr" rid="ref6 ref7 ref8 ref9">6–9</xref>
        ], detection of estrus [
        <xref ref-type="bibr" rid="ref10 ref11">10,11</xref>
        ] or even mating [
        <xref ref-type="bibr" rid="ref12">12</xref>
        ].
      </p>
      <p>
        Most existing commercial solutions, as well as academic work, have been developed for cattle,
due to the greater value of these animals, for small ruminants there is a smaller set of monitoring
solutions, but they focus especially on issues related to the location of the animals. For these
ruminants, monitoring behavior and activity is mostly described in academic works, typically using
on loggers [
        <xref ref-type="bibr" rid="ref13 ref14 ref15">13–15</xref>
        ], without the possibility of real-time monitoring.
      </p>
      <p>Present work presents a ruminant monitoring platform based on the use of wearable inertial
sensors, integrated with an edge located animal behavior classification unit implemented in a
gateway resident in livestock facilities, which is interconnected with a cloud application that
aggregates data from different livestock facilities. Paper describes system components and tools and,
it illustrates its operation in several monitoring scenarios.</p>
    </sec>
    <sec id="sec-2">
      <title>2. Monitor system overview</title>
      <p>The monitoring system, illustrated in Figure 1, includes sensor collars, gateways, and mobile
devices (i.e. cellular phone, tablet) and can be integrated with video collection devices to enrich the
monitoring process. Communication between the collars and the aggregating gateway is carried out
opportunistically via a Bluetooth Low Energy (BLE) [17] interface, and the collars have an internal
memory that allows monitoring data to be stored when there is no radio coverage with the gateway.
When this coverage is recovered, the collars begin a process of transmitting the stored data to the
gateway, which reconditions and transmits it to the application residing in the cloud. The system
relies on data sent from various gateways to perform data mining and to build learning models,
taking advantage of the diversity of facilities and characteristics of the herds.</p>
      <p>BLE communication is also used to implement communication between collars and mobile
devices, allowing individual monitoring in situ, as checking the operation status of the device, the
battery charge, as well to configure it and change the firmware over the air. It is also used in the
learning mode, a scenario in which a mobile app uses the device's camera to record video and
synchronously collect sensor data from the animal. The collar also includes a Near Field
Communications (NFC) [18] interface, a technology present in most mobile devices, which is used
as a virtual collar control button, allowing the device to be turned on and off, or in an integrated
with the BLE interface process, to perform collar maintenance and monitoring tasks as illustrated in
Figure 2. Collar monitorization is performed centrally as well, through a web interface implemented
by a cloud application, as illustrated in Figure 3.</p>
      <p>Some learning processes require long periods of monitoring, such as calving, estrous and mating,
so the system can additionally be integrated with video image collection devices, which are
temporally synchronized with the gateway to guarantee the synchronization of telemetry data and
the images, and thus allow the subsequent process of data supervision [19].</p>
      <p>The collar includes a three-axis accelerometer and a thermometer, and it supports operating
frequencies between 0.03 and 20 Hz. In monitoring mode, it uses a variable sampling rate that creates
a new data sample whenever the algorithm detects a new behavior, or after 30 seconds have passed.
In learning mode, the sampling frequency is parameterized according to the objectives of the specific
learning process, with a value between 1 and 20Hz. The collar operates on battery power and
guarantees an autonomy up to 150 days between battery charges.</p>
      <p>The gateway (Figure 4) is implemented by a microcomputer present in the livestock facilities,
next to the collars, and it interconnects them with a cloud-resident application that stores, analyzes,
and allows access to the data to the human operator, as illustrated in Figure 5. The gateway also
implements simpler data analysis mechanisms, and generates alarms, such as equipment anomalies
or those associated with animal behavior, such as birth detection.</p>
      <p>The cloud-resident application centralizes monitoring data from all livestock facilities and stores
it for centralized analysis and updating learning models.</p>
    </sec>
    <sec id="sec-3">
      <title>3. System operation</title>
      <p>Collar periodically reads sensor values and classifies animal behaviors according to the operating
mode configured, as described in Table 1. Monitoring mode operation implements animal
classification such as classifying behaviors according to the defined ethogram (eating, walking,
chewing, lying down, resting) (Figure 6) or detecting birth events in the case of goats. In addition to
classifying behavior with a 0,5 Hz frequency, it transfers monitoring data to the gateway, which in
turn analyzes and transfers it to the cloud application. Monitoring mode allows up to 150 days of
storage autonomy and 1600 days of battery autonomy.</p>
      <p>Learning modes were designed to carry out learning operations, whereby the system collects data
from sensors and stores it with a timestamp of the moment of collection, so that this data can be
externally annotated with the help of other information and use to carry out learning operations. To
allow different learning processes with different dynamism, two modes with two sampling
frequencies were implemented. The mode Learning samples data at a frequency of 1Hz and has a
battery autonomy of 120 days, while Special Learning mode implements a 20Hz sampling and offers
a battery autonomy of 60 days and a storage autonomy of 800 days.</p>
      <p>Regardless of the mode of operation, the collar periodically transfers the classification of
behaviors and accelerometry data (see Figure 7) to the gateway, so that it is transferred to the
cloudhosted application, where it can be mined and made available to the human supervisor. In the case
of events that require timely intervention by the animal handler, such as birth detection events, the
gateway's alarm generation module sends a notification message directly to the contact defined in
the gateway.</p>
      <p>The transfer of accelerometer data through the gateway also allows analyzing animal activity
over time as illustrated in Figure 7, and comparing it with previous periods of the same animal or
with other animals in the herd.</p>
      <p>The learning mode performs the sensing of animal behavior in terms of reading accelerometer
and thermometer values, and subsequently sending the data stream abroad. This data is later
supervised and used to build learning models. iRumMon allows two learning scenarios: for short
learning processes in which the aim is to monitor behavior through human presence, an Android
app is used (Figure 8); for longer learning processes in which it is not possible to keep the human
operator in the presence of the animal, a video image capture device (Figure 9) and gateway are
used. In either case, communication is carried out via BLE, either with the Android app or with the
gateway.</p>
      <p>In more temporally extensive learning processes, the collars are interconnected with the gateway
and a video camera with temporal synchronization support, is used (Figure 9), such as an Internet
access camera that allows automatic configuration of the system time. In this type of scenario,
iRumMon allows the learning process regarding several animals simultaneously, as long as the
collection of images of the animals involved is guaranteed. As in the monitoring scenario with the
app, once the monitoring session is over, data from the various collars and video images are extracted
to enable the data monitoring process.</p>
    </sec>
    <sec id="sec-4">
      <title>4. Conclusions</title>
      <p>Animal monitoring using wearable inertial sensors is a low-cost technique with enormous
possibilities for monitoring animals and their well-being. This paper presents an animal monitoring
solution, developed for monitoring ruminants and which has been used, for example, to monitor the
S
S
S
S
S
activity and behavior of sheep, detecting goat births. The paper presents the system components and
briefly describes their operating modes and characteristics.</p>
      <p>The system, whose development has been completed, should be equipped with a new, smaller and
lighter version in the near future, in order to allow the monitoring of other animals, such as smaller
animals, or even birds.</p>
    </sec>
    <sec id="sec-5">
      <title>Declaration on Generative AI</title>
      <p>The author(s) have not employed any Generative AI tools.</p>
    </sec>
  </body>
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