<!DOCTYPE article PUBLIC "-//NLM//DTD JATS (Z39.96) Journal Archiving and Interchange DTD v1.0 20120330//EN" "JATS-archivearticle1.dtd">
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  <front>
    <journal-meta>
      <journal-title-group>
        <journal-title>Semantic
Web (to appear). http://www.semantic-web-journal.net/.
5. A. Gangemi and V. Presutti</journal-title>
      </journal-title-group>
      <issn pub-type="ppub">1613-0073</issn>
    </journal-meta>
    <article-meta>
      <article-id pub-id-type="doi">10.1007/978-3-540-92673-3</article-id>
      <title-group>
        <article-title>Two Ontology Design Patterns toward Energy E ciency in Buildings</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Iker Esnaola-Gonzalez</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Jesus Bermudez</string-name>
          <email>jesus.bermudez@ehu.eus</email>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Izaskun Fernandez</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Aitor Arnaiz</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>IK4-TEKNIKER</institution>
          ,
          <addr-line>In~aki Goenaga 5, 20600 Eibar</addr-line>
          ,
          <country country="ES">Spain</country>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>University of the Basque Country (UPV/EHU)</institution>
          ,
          <addr-line>Paseo Manuel Lardizabal 1, 20018 Donostia-San Sebastian</addr-line>
          ,
          <country country="ES">Spain</country>
        </aff>
      </contrib-group>
      <pub-date>
        <year>2043</year>
      </pub-date>
      <volume>25</volume>
      <abstract>
        <p>Achieving an energy e cient operation of a building is not a straightforward task. In this article, two Ontology Design Patterns (ODP) are proposed, motivated by speci c challenges that arise in this domain, and with the intention to support data analysts towards this goal. The two proposed ODPs are the A ectedBy ODP and the EEP (Execution-Executor-Procedure) ODP, which is an extension of the rst. Both of them are intended to ll the gap that existing ontologies and ODPs fail to address adequately. Furthermore, both ODPs are aligned to an upper level ontology and some other related ontologies, which makes them applicable to other domains and scenarios.</p>
      </abstract>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>Introduction</title>
      <p>
        Buildings and construction account for more than 35% of global energy use and
nearly 40% of energy-related CO2 emissions [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ]. This is why e cient
management of building energy plays a vital role and is becoming the trend for a future
generation of buildings. Furthermore, since people spend more than 85% of their
time in buildings [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ], feeling comfortable while staying indoors is a must. In
this context, the convergence of the Internet of Things' (IoT) rapid spread and
the Knowledge Discovery in Databases (KDD) is expected to lead to signi cant
progress. A KDD process can be understood as a ve step process to extract
useful knowledge from raw data and, in the energy e ciency eld for buildings, they
have traditionally been employed for tasks such as energy consumption
forecasting [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ]. However, having insu cient domain expertise can make data analysts
feel overwhelmed throughout this process, resorting to a trial-and-error approach
searching for variables and tasks to make accurate predictions. Consequently, the
KDD process becomes arduous and time-consuming.
      </p>
      <p>The EEPSA (Energy E ciency Prediction Semantic Assistant) process
addresses this problem taking leverage of Semantic Technologies like ontologies,
ontology-driven rules and ontology-driven data access to guide data analysts
through the di erent KDD phases in a semi-automatic manner, towards the
enhancement of the KDD process [4]. In this process, the EEPSA ontology3 plays
a vital role capturing the necessary knowledge, mainly related to buildings,
sensing and actuating devices, and their corresponding observations and actuations.
This knowledge, along with other relevant domain and expert knowledge for the
matter at hand, is captured in well-decoupled modules and represented in a form
that can support data analysts.</p>
      <p>In this paper, two Ontology Design Patterns (ODP) are proposed: the
AffectedBy ODP and the Execution-Executor-Procedure (EEP) ODP, which is an
extension of the A ectedBy ODP. Both ODPs are motivated by speci c
challenges that arise in problems related to energy e ciency in buildings, and they
are de ned with the intention to support data analysts throughout the KDD
process. These two ODPs form the core of the renewed version of the EEPSA
ontology. Furthermore, both ODPs are aligned to an upper level ontology and
some other related ontologies, which makes them applicable to other domains
and scenarios.</p>
      <p>The rest of this paper is structured as follows. Section 2 introduces the related
work. Section 3 describes the two ODPs. Finally, the conclusions of this work
are presented in section 4.
2</p>
    </sec>
    <sec id="sec-2">
      <title>Related Work</title>
      <p>The energy e ciency in buildings domain spans concepts that overlap with the
IoT eld such as spaces, devices, observations, procedures, properties, and units
of measurements to name a few. Some ontologies have considered these issues
in their universe of discourse. However, the intended broad scope of these
ontologies, usually cause large and complex bodies of terminology, and sometimes
introduce too speci c commitments that provoke a hard learning curve and
hinder their reuse. An encouraging ontology design methodology to unlock these
problems is the pattern-based ontology design. An ODP is a modelling solution
to solve a recurrent ontology design problem [5]. Ideally, ODPs should be
extendable but self-contained, minimize ontological commitments to foster reuse,
address one or more explicit requirements (such as use cases or competency
questions), be associatable to an ontology unit test, be the representation of a core
notion in a domain of expertise, be alignable to other patterns, span more than
one application area or domain, address a single invariant instead of targeting
multiple reocurring issues at the same time, follow established modelling best
practices, and so forth [6]. Following, a quick review of ODP-based ontologies
related to sensing and actuating devices, and their context, is presented.</p>
      <p>The DOLCE+DnS Ultralite (DUL4) ontology is a simpli cation of some
parts of the DOLCE Lite-Plus library and Descriptions and Situations ontology.
It is an upper-level ontology, and it de nes general terms that are common
across di erent domains. Therefore, it supports a broad semantic interoperability
3 https://w3id.org/eepsa
4 http://www.ontologydesignpatterns.org/ont/dul/DUL.owl
among domain-speci c ontologies by providing a common starting point for the
formulation of de nitions.</p>
      <p>The Semantic Sensor Network (SSN) ontology [7] was developed by the W3C
Semantic Sensor Networks Incubator Group (SSN-XG5) and described sensors,
observations and methods used for sensing among other concepts. It was aligned
with the DUL ontology and built around a central ODP called
Stimulus-SensorObservation [8] (SSO) describing the relationship between sensors, stimulus and
observations. The W3C Spatial Data on the Web Working Group (SDWWG6)
proposed an update of the SSN ontology7 that became a W3C recommendation.
The new version of the SSN ontology8 follows a horizontal and vertical
modularization architecture by including a lightweight but self-contained core ontology
called SOSA9 (Sensor, Observation, Sample, and Actuator) for its elementary
classes and properties. Furthermore, similar to the original SSO patterns, SOSA
acts as a central building block for the new SSN ontology. In line with the changes
implemented for the new SSN ontology, SOSA also avoids the direct DUL import
that previous version had, although an optional alignment can be achieved via
the SSN-DUL alignment module10.</p>
      <p>The Actuation-Actuator-E ect11 (AAE) ODP intends to model the
relationship between an Actuator and the E ect it has on its environment through
Actuations. This pattern adapts the SSN ontology's SSO ODP for actuators.
The new version of the SSN ontology covers the function of the AAE ODP for
actuators by expanding the SSO pattern in the SOSA ontology.</p>
      <p>The SSN ontology does not provide enough constraints to the de nitions of
classes and properties to guarantee a proper answer to a question like: what is
the feature of interest corresponding to a given property that has been observed
by a sensor? And neither to this other question: which sensors observe a given
property of a feature of interest? The patterns proposed in this paper solve these
problems.</p>
      <p>The SmartEnv ontology, proposed as a representational model to assist the
development process of smart environments, is a network of 8 di erent ODPs [9].
These ODPs are used to modularize the proposed solution, while at the same
time avoiding strong dependencies between the modules to manage the
representational complexity of the ontology. The SmartEnv relies on the SSN ontology
without introducing enough constraints to solve the aforementioned weaknesses
of the SSN ontology.</p>
      <p>The SEAS Ontology[10] is an ontology designed as a set of simple core ODPs
that can be instantiated for multiple engineering related verticals. It is planned
5 https://www.w3.org/2005/Incubator/ssn/
6 http://www.opengeospatial.org/projects/groups/sdwwg
7 https://www.w3.org/TR/vocab-ssn/
8 http://www.w3.org/ns/ssn/
9 http://www.w3.org/ns/sosa/
10 http://www.w3.org/ns/ssn/dul
11 http://ontologydesignpatterns.org/wiki/Submissions:</p>
      <p>Actuation-Actuator-Effect
to be added to the SAREF (Smart Appliances REFerence) ontology12, which
is expected to ease its adoption and extension by industrial stakeholders, while
ensuring easy maintenance of its quality, coherence, and modularity [11]. The
SEAS Feature of Interest ontology13, is one of the modules that forms the SEAS
ontology, and de nes features of interest (seas:FeatureOfInterest ) and
properties (seas:Property). The Procedure Execution ontology14 (PEP) de nes
procedure executors that implement procedure methods, and generate procedure
execution activities. Furthermore, PEP de nes an ODP as a generalization of
SOSA's sensor-procedure-observation and actuator-procedure-actuation models.
The patterns proposed in this paper are a reengineering of the PEP and the
FeatureOfInterest ontologies and, additionally, an integration of them into a single
ODP.</p>
      <p>The Observation15 ODP aims at representing observations of things, under a
set of parameters. This set of parameters may include the place where the
observation was made, the time when it was made, and any other feature concerning
the speci c thing being observed.</p>
      <p>The IoT Application Pro le (IoT-AP) ontology, is an ontology for
representing and modelling the knowledge within the domain of the IoT [12]. The ontology
is designed re-using ODPs such as the aforementioned Observation ODP. It
focuses in observations, but it also covers sensors that make those observations,
values of those observations and observation collections. However, this ontology
su ers from similar weaknesses to those previously commented about the SSN
ontology. This is basically due to the lack of proper constraints on property
de nitions.</p>
      <p>The ODP repository16 collects and makes ODPs available on the web,
allowing users to download, propose, and discuss them. Some of the mentioned ODPs
are hosted in this repository.
3</p>
    </sec>
    <sec id="sec-3">
      <title>Motivation and Pattern Overview</title>
      <p>The EEPSA ontology supports data analysts that are not experts in the energy
e ciency in tertiary buildings domain, towards the creation of enhanced
predictive models. For that purpose, the ontology not only needs to contain both
domain knowledge and expert knowledge, but also needs to represent it in a way
that can be leveraged to guide data analysts throughout the KDD process.</p>
      <p>In energy e ciency problems related to tertiary buildings domain, two
recurrent modelling challenges arise. The rst one is related to modelling variables
that may a ect an indoor condition such as indoor temperature or occupancy.
The second one is related to modelling the variables measured within a building
and the systems to measure them. The de nition of ODPs for these problems
12 https://w3id.org/saref
13 https://ci.mines-stetienne.fr/seas/FeatureOfInterestOntology
14 https://ci.mines-stetienne.fr/pep/
15 http://ontologydesignpatterns.org/wiki/Submissions:Observation
16 http://www.ontologydesignpatterns.org
would be bene cial and could ideally act as building blocks to be reused in case
someone else faces these same modelling challenges.
3.1</p>
      <sec id="sec-3-1">
        <title>A ectedBy</title>
        <p>In the rst phase of a typical KDD process, known as the Data Selection phase,
the EEPSA process supports data analysts selecting datasets and subset of
variables or data samples that are relevant for the matter at hand. Taking into
account that data analysts may not be experts in the energy e ciency in
tertiary buildings domain, they may feel overwhelmed during this task, due to their
lack of expertise in choosing the adequate variables. Therefore, they would
bene t from a resource that supports the discovery of relevant variables that a ect
the environment of a given space or another feature of interest. Any of these
variables will be represented as properties or qualities of a feature of interest.</p>
        <p>For example, let us consider the LR03 lecture room as a feature of interest: a
lecture room located on the ground oor of a building, and with a large window
that overlooks the road that passes near the building. Some properties of LR03
are: the area of the lecture room, the number of seats available or the quality
of comfort at any given time. The quality of comfort in this lecture room is
a ected by the room temperature and the nearby outdoor noise. In turn, the
temperature of LR03 is a ected by the number of people present in the lecture
room, the humidity of the lecture room, and the intensity of solar radiation
received through the room window. Regarding the impact of outdoor noise, it
is a ected by the sound insulation factor of the room. Lastly, the received solar
radiation is a ected by the azimuth (i.e. orientation) of the lecture room window.</p>
        <p>The following competency questions must be considered:
{ CQ1: What are the properties/qualities of a feature of interest?
{ CQ2: What are the properties/qualities that a ect a given property of a
feature of interest?
{ CQ3: Which feature of interest does a given property/quality belongs to?</p>
        <p>The SSN Ontology contains a building block that may be useful for this
matter. However, an inadequacy was spotted. The ssn:Property class is
textually de ned as \a quality of an entity. An aspect of an entity that is intrinsic
to and cannot exist without the entity". This de nition is made basically,
according to the de nition of the dul:Quality class. In fact, it is declared17 that
ssn:Property rdfs:subClassOf dul:Quality. Furthermore, the ssn:Property class
is linked to the ssn:FeatureOfInterest class with the ssn:isPropertyOf object
property. Nevertheless, this object property is not functional, meaning that the
ssn:isPropertyOf property can have more than one value for the same individual,
so the following triples can be found in a ssn-annotated triple set:
:temperature rdf:type ssn:Property.</p>
        <p>:temperature ssn:isPropertyOf :lr03.
17 https://www.w3.org/TR/vocab-ssn
:lr03 rdf:type ssn:FeatureOfInterest.
:temperature ssn:isPropertyOf :lr07.
:lr07 rdf:type ssn:FeatureOfInterest.
:lr03 owl:differentFrom :lr07.</p>
        <p>According to the aforementioned ssn:Property 's class textual de nition,
individual :temperature is intrinsic to and cannot exist without the existence of
individual :lr03. However, the triples shown contradict such de nition (i.e.,
:temperature is a quality of di erent entities). Probably, designers of the SSN
ontology would advise against this practice and, in fact, example \B.3 apartment
134"18 uses the URI &lt;apartment/134/electricConsumption&gt; for referring to an
individual that represents the electrical consumption of the apartment #134.
However, the identi cation of the feature of interest (i.e., apartment #134) of
this property is embedded in the URI and this is not enough for machine
interpretation. Of course, two di erent rooms may have the same temperature value
(e.g. 15 C) but such circumstance would be represented as a property value of
each di erent temperature instances. Moreover, a suitable hierarchy of Property
subclasses may be desirable. A class Temperature would be a subclass of class
Property. Therefore, it could be possible to ask for all the features of interest
that have a temperature quality.</p>
        <p>The issue mentioned above is tackled in the SEAS Feature of Interest
ontology, where an ODP to describe features of interest and their properties is de ned.
In this pattern, the seas:isPropertyOf object property links a seas:Property to
a seas:FeatureOfInterest, and it is declared as subproperty of ssn:isPropertyOf.
However, seas:isPropertyOf is functional. Therefore, it represents more faithfully
the textual de nition of ssn:Property.</p>
        <p>Furthermore, the SEAS Feature of Interest ontology also de nes the
seas:derivesFrom object property which links a seas:Property to another seas:Property
it derives from. This object property is de ned as a symmetric property, which
means that the property has itself as inverse. However, this constraint is
unnecessary and sometimes even inappropriate. For instance, the temperature of
individual :lr03 may derive from the occupancy of the room, but the occupancy
does not necessarily derive from the temperature of the room.</p>
        <p>In addition, the SEAS Feature of Interest ontology contains a textual
comment that, although relevant, it is not materialized as an axiom:
seas:hasProperty &lt;seas:hasProperty</p>
        <p>seas:derivesFrom</p>
        <p>The A ectedBy ODP is inspired by the identi ed SSN ontology and SEAS
Feature of Interest ontology weaknesses. It de nes the building block shown in
Figure 1, that consists of two classes: a :FeatureOfInterest and a :Quality, and
three properties: a :hasQuality, a :belongsTo, and a :a ectedBy.
18 https://www.w3.org/TR/vocab-ssn/#apartment-134</p>
        <p>Fig. 1. The A ectedBy ODP.</p>
        <p>The property a :a ectedBy (released from the symmetric constraint) is
dened in the A ectedBy ODP to replace the role of the property seas:derivesFrom.
It can be asserted that seas:derivesFrom is a subproperty of a :a ectedBy. The
class a :FeatureOfInterest is equivalent to seas:FeatureOfInterest, and the class
seas:Property is equivalent to a :Quality. Moreover, seas:hasProperty is
subproperty of a :hasQuality, and seas:isPropertyOf is subproperty of a :belongsTo.
Furthermore, a :belongsTo is de ned to be functional and it is the inverse of
a :hasQuality, to support the notion that a quality is intrinsic to the feature of
interest (i.e., an entity) to which it belongs (according to the conceptualization
in DUL); and it is also asserted that every quality belongs to a feature of
interest, i.e.,
a :Quality rdfs:subClassOf a :belongsTo some a :FeatureOfInterest).
Finally, the following property chain axiom is asserted:
a :hasQuality</p>
        <p>a :a ectedBy rdfs:subPropertyOf a :hasQuality</p>
        <p>Even though the ODP is motivated by the energy e ciency in buildings
problem, it is applicable to similar problems from di erent domains. Therefore,
the A ectedBy ODP is aligned with the DUL ontology. Moreover, the A ectedBy
ODP is also aligned to the SSN Ontology and the SEAS Feature of Interest
ontology. The alignments with these three ontologies are kept in separate les19.
19 https://github.com/iesnaola/AffectedBy/tree/master/alignments
Likewise, the HTML documentation of the ODP is available20 via LODE (Live
OWL Documentation Environment [13]) and in the ODP repository21.
Application. The instantiation of the A ectedBy ODP for the aforementioned
LR03 lecture room is shown in Figure 2. For the sake of simplicity, the rdf:type
relationships are not shown.</p>
        <p>With respect to this example, the following competency questions can be
applied and answered:
{ (CQ2): What are the properties that a ect the property :lr03Comfort ?
SPARQL query: SELECT ?x WHERE f:lr03Comfort a :a ectedBy ?x.g
Answer: :lr03Temperature, :lr03OutdoorNoise.
{ (CQ2): What are the properties that a ect the property :lr03Temperature?
SPARQL query: SELECT ?x WHERE f:lr03Temperature a :a ectedBy ?x.g
Answer: :lr03Occupancy, :lr03Humidity, :lr03SolarRadiation.
{ (CQ1): What are the properties of the feature of interest :lr03 ?
SPARQL query: SELECT ?x WHERE f:lr03 a :hasQuality ?x.g
Answer: :lr03Area, :lr03NumSeats :lr03Comfort, :lr03Temperature,
:lr03OutdoorNoise, :lr03Occupancy, :lr03Humidity, :lr03SolarRadiation,
:lr03SoundInsulation, :lr03WindowAzimuth.
(After inferences provided by the axiom a :hasQuality a :a ectedBy
rdfs:subPropertyOf a :hasQuality ).
{ (CQ3): Which feature of interest does the property :lr03SolarRadiation
belongs to?</p>
        <p>SPARQL query: SELECT ?x WHERE f:lr03SolarRadiation a :belongsTo
20 https://w3id.org/affectedBy
21 http://ontologydesignpatterns.org/wiki/Submissions:AffectedBy
?x.g
Answer: :lr03.
(After inferences provided by the axioms a :hasQuality a :a ectedBy
rdfs:subPropertyOf a :hasQuality and a :belongsTo inverseOf
a :hasQuality).
3.2</p>
      </sec>
      <sec id="sec-3-2">
        <title>Execution-Executor-Procedure (EEP)</title>
        <p>An interesting information for data analysts could be: which are the
sensors/actuators deployed in the space where the energy e ciency is aimed? And even
more: which are the capabilities of those sensors/actuators? Moreover, knowing
this information would let data analysts make further queries to discover sensors
or actuators that observe or act on a given property of a space. More speci cally,
the CQs considered are the following:
{ CQ1: What are the observations/actuations performed by a given procedure?
{ CQ2: What are the observations/actuations performed by a given
sensor/actuator?
{ CQ3: What are the procedures implemented by a given sensor/actuator?
{ CQ4: What are the features of interest on a given observation/actuation?
{ CQ5: What are the properties/qualities sensed/actuated by a given
observations/actuations?
{ CQ6: What are the features of interest of a given sensor/actuator?
{ CQ7: What are the properties/qualities sensed/actuated by a given
executor?</p>
        <p>For each competency question CQn, we can consider a twin competency
question CQni which consists on rephrasing the question in the opposite direction.
For instance, CQ1i is de ned as \What is the procedure used in a given
observation/actuation?". In terms of a SPARQL query, it means that the query
variable is moved from the subject position to the object position, or the other
way round, of the triple pattern.</p>
        <p>These questions have been tackled by the SSN ontology with SOSA's
Observation-Sensor-Procedure pattern, and by the SAN ontology with the AAE
pattern. However, in their current state, they cannot properly ful l the discovery
of sensors and actuators because no property has been de ned that directly
links sensors or actuators to features of interest, and moreover, compositions of
properties that link them through the Observation or Actuation class, are not
su ciently constrained to satisfy the aforementioned competency questions. For
instance, the following set of ssn-annotated triples is not enough to answer the
question: which is the sensor that observes the temperature of :lr07?
:sensor1 sosa:madeObservation :obs1;</p>
        <p>sosa:observes :temperature.
:temperature ssn:isPropertyOf :lr03.
:obs1 sosa:hasFeatureOfInterest :lr03.
:sensor2 sosa:madeObservation :obs2;</p>
        <p>sosa:observes :temperature.
:temperature ssn:isPropertyOf :lr07.
:obs2 sosa:hasFeatureOfInterest :lr07.
:sensor1 sosa:madeObservation :obs3;</p>
        <p>sosa:observes :humidity.
:humidity ssn:isPropertyOf :lr07.
:obs3 sosa:hasFeatureOfInterest :lr07.</p>
        <p>In order to ll this gap, the Execution-Executor-Procedure (EEP) ODP
presented in this paper represents executions (e.g., events such as observations or
actuations) made by executors (e.g., systems such as sensors or actuators) that
implement procedures to carry out their goals. Executions and executors are
taken over features of interest and their intrinsic properties or qualities.</p>
        <p>The EEP ODP is an adaptation of the PEP ontology from the SEAS
ontology which, in turn, is a generalization of the Observation-Sensor-Procedure and
Actuation-Actuator-Procedure patterns used in the SOSA and SSN ontologies.
The EEP ODP imports the A ectedBy ODP that involves classes for features
of interest and their intrinsic properties/qualities. Furthermore, from the A
ectedBy ODP, the EEP ODP imports the notion that a property/quality is intrinsic
to the feature of interest that it belongs to (i.e., according to the de nition of
the class Quality in the DUL ontology).</p>
        <p>Apart from the two classes (i.e., a :FeatureOfInterest and a :Quality)
imported from the A ectedBy ODP, the EEP ODP consists of three more classes:
eep:Execution, eep:Executor, and eep:Procedure (see Figure 3). An individual of
eep:Execution is an action related to a property of a feature of interest,
produced by an agent by performing a procedure. An individual of eep:Executor
is an agent capable of performing tasks by following procedures. An
individual of eep:Procedure is a description of some actions to be executed by agents.
The class eep:Execution and their three functional object properties eep:madeBy,
eep:usedProcedure, and eep:onQuality, form the backbone of the ODP. The
property eep:madeBy links an execution to the agent that performs the action; the
property eep:usedProcedure links an execution to the procedure that describes
the task to be performed; and the property eep:onQuality links an execution
to the quality/property concerned by the execution. Therefore, an execution
jointly with their three object values of the three aforementioned properties
can be considered as a n-ary relationship. Note that every quality belongs to a
unique feature of interest, so a feature of interest is also involved in the n-ary
relationship.</p>
        <p>The remaining object properties are: eep:implements, linking executors to
procedures; eep:hasFeatureOfInterest, linking executions to features of interest;
eep:forQuality, linking executors to qualities; and eep:forFeatureOfInterest,
linking executors to features of interest. Note that an executor can implement
different procedures corresponding to di erent executions performed by the same
executor. Analogously, an executor may be committed to di erent properties and
features of interest. These four properties are de ned in terms of the functional</p>
        <p>Fig. 3. The Execution-Executor-Procedure (EEP) ODP.
object properties using the following property chain axioms:
inverse(eep:madeBy) eep:usedProcedure rdfs:subPropertyOf eep:implements.
eep:onQuality eep:belongsTo rdfs:subPropertyOf eep:hasFeatureOfInterest.
inverse(eep:madeBy) eep:onQuality rdfs:subPropertyOf eep:forQuality.
eep:forQuality eep:belongsTo rdfs:subPropertyOf eep:forFeatureOfInterest.</p>
        <p>Axioms included in the EEP ODP provide inferences that allow to answer
the formulated CQs properly, solving the previously referred weaknesses of the
sosa/ssn ontologies. Note that only triples about the four functional object
properties eep:madeBy, eep:usedProcedure, eep:onQuality, and a :belongsTo, need to
be asserted, and the remaining triples are inferred by the property axioms.</p>
        <p>Likewise the A ectedBy ODP, the EEP ODP is motivated by the energy
e ciency in buildings problem but it is applicable to di erent domains. It is
aligned with the DUL ontology, the SSN Ontology, and the PEP ontology. The
alignments with these three ontologies are kept in separate les22. Furthermore,
the HTML documentation of the ODP is available23 via LODE and in the ODP
repository24.
22 https://github.com/iesnaola/EEP/tree/master/alignments
23 https://w3id.org/eep
24 http://ontologydesignpatterns.org/wiki/Submissions:EEP
Application. The EEP ODP is instantiated in a farm scenario where poultry
are reared. In this case, a sensor :sensor36 deployed in the farm individual
:farm is in charge of measuring both farm's temperature and humidity (i.e.,
:farmTemperature and :farmHumidity ). Furthermore, this sensor implements a
monitoring procedure (:monitoringProc) to make two observations :obs13 and
:obs14. Figure 4 shows this instantiation.</p>
        <p>With respect to this example, the following competency questions can be
applied and answered:
{ (CQ1): What are the executions performed by procedure :monitoringProc?
SPARQL query: SELECT ?x WHERE f?x eep:usedProcedure
:monitoringProc.g</p>
        <p>Answer: :obs13, :obs14.
{ (CQ2): What are the observations performed by sensor :sensor36 ?
SPARQL query: SELECT ?x WHERE f?x eep:madeBy :sensor36.g
Answer: :obs13, :obs14.
{ (CQ3): Which are the procedures implemented by the sensor :sensor36 ?
SPARQL query: SELECT ?x WHERE f:sensor36 eep:implements ?x.g
Answer: ::monitoringProc
(After inferences provided by the axiom inverse(eep:madeBy)
Procedure rdfs:subPropertyOf eep:implements ).
eep:used{ (CQ4i): What are the executions on the feature of interest :farm?
SPARQL query: SELECT ?x WHERE f?x eep:hasFeatureOfInterest :farm.g
Answer: :obs13, :obs14.
(After inferences provided by the axioms eep:onQuality eep:belongsTo
rdfs:subPropertyOf eep:hasFeatureOfInterest and a :belongsTo inverseOf
a :hasQuality ).
{ (CQ5): What are the qualities observed by the observation :obs13 ?
SPARQL query: SELECT ?x WHERE f:obs13 eep:onQuality ?x.g
Answer: :farmTemperature.
{ (CQ6i): What are the executors that observe/act on the feature of interest
:farm?
SPARQL query: SELECT ?x WHERE f?x eep:forFeatureOfInterest :farm.g
Answer: :sensor36.
(After inferences provided by the axioms eep:forQuality
eep:belongsTo rdfs:subPropertyOf eep:forFeatureOfInterest and
inverse(eep:madeBy) eep:onQuality rdfs:subPropertyOf eep:forQuality ).
{ (CQ7): What are the qualities observed by sensor :sensor36 ?
SPARQL query: SELECT ?x WHERE f:sensor36 eep:forQuality ?x.g
Answer: :farmTemperature, :farmHumidity.
(After inferences provided by the axiom inverse(eep:madeBy) eep:onQuality
rdfs:subPropertyOf eep:forQuality ).</p>
        <p>The EEP ODP presented in this paper left out the temporal context, which
undoubtedly is a relevant issue. In fact, EEP can be easily extended by importing
di erent conceptualizations of such temporal aspect. For instance, a simple
solution is to de ne a property like :atTime linking eep:Execution to :TimeInterval
(like in IoT-AP ontology, or similarly in Fiesta-IoT ontology [14]), and
additionally to include some other property like sosa:resultTime linking eep:Execution
to xsd:dateTime in order to di erentiate the temporal entity that applies to the
execution from the instant the execution was completed (as it is made in SOSA
ontology). Moreover, a more complex conceptualization may be necessary in a
scenario where executions are also features of interest and time is a quality of
these executions, then :Time may be a subclass of a :Quality (similarly to what
is done in SAREF ontology). Otherwise, features of interest and their properties
may need to be quali ed by time-related properties; for instance, state duration
of a feature of interest or change frequency of a property during a temporal
context (as it is proposed in the SEAS Time Ontology25). In summary, EEP is
ready to incorporate the preferred solution adopted by the EEP user.
25 https://ci.mines-stetienne.fr/seas/TimeOntology</p>
      </sec>
    </sec>
    <sec id="sec-4">
      <title>Conclusions and Future Work</title>
      <p>In this paper we presented two ODPs: the A ectedBy ODP and the EEP
(Execution-Executor-Procedure) ODP, which is an extension of the rst. Both of them
are expected to solve recurrent design problems that arise in energy e ciency
problems for buildings and that are not adequately addressed by existing
ontologies and ODPs. Both ODPs are aligned with related ontologies which make
them applicable to similar problems in di erent domains, and are stored in the
ODP repository.</p>
      <p>In future work, both ODPs are expected to be the base for building ontology
modules. Namely, they are planned to be the foundation for the reengineering
of the measurements4EEPSA ontology module (an adapted extraction of the
m3-lite26 and QUDT27 ontologies) responsible for containing measurements and
device related knowledge, and a new ontology module containing expert
knowledge in the energetic eld.</p>
      <p>Furthermore, these ODPs will be used in KDD processes with other goals that
di er from attempting an energy e cient management of a building. Namely,
they are expected to support the energy production forecasting of a Photovoltaic
(PV) system as well as the management of Demand-Response strategies.</p>
    </sec>
    <sec id="sec-5">
      <title>Acknowledgement</title>
      <p>Part of the presented work received funding from
FEDER/TIN2016-78011-C42-R. This work was conducted using the Protege resource, which is supported
by grant GM10331601 from the National Institute of General Medical Sciences
of the United States National Institutes of Health.
26 http://ontology. esta-iot.eu/ontologyDocs/m3-lite.owl
27 http://www.qudt.org</p>
    </sec>
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