Explain Yourself: A Semantic Annotation Framework to Facilitate
Tagging of Semantic Information in Health Smart Homes
Bastian Wollschlaeger
a
, Elke Eichenberg and Klaus Kabitzsch
Chair of Technical Information Systems, Technische Universität Dresden, 01062 Dresden, Germany
Keywords:
Ambient Assisted Living, Digital Personalized Health, Health Smart Home, Interoperability, Taxonomy,
Telehealth, Telemedicine.
Abstract:
Health Smart Homes (HSH) are a key concept in future personalized health care. However, with an abundance
of heterogeneous assistance components available, the design process of HSHs is becoming increasingly com-
plex and needs to rely on computer-based support. As a key prerequisite, formal models of information se-
mantics are required for component selection and early-on interoperability assessment. This paper proposes a
flexible and extensible framework of semantic annotations that copes with the interdisciplinary nature of HSH
and can be used to incorporate a formal model of semantics at component interfaces. The framework consists
of a taxonomy of semantic annotations (tags) and their relationships and is developed using a well-established
taxonomy creation method. The tags address several independent aspects of semantics, increasing the expres-
siveness of information semantics. With this valuable new level of detail for information, component models
can be semantically enriched, in turn enabling computer-based design algorithms to carry out the complex
design tasks in the future.
1 INTRODUCTION
Health Smart Homes (HSH) are a key concept for re-
alizing personalized health care in order to cope with
future challenges for health care systems (Maeder and
Williams, 2017). However, with an abundance of
heterogeneous assistance components available, the
design process for HSH is becoming increasingly
complex and requires computer-based support (Haux
et al., 2016; Welge et al., 2015). In order to allow al-
gorithms to identify meaningful design suggestions,
formal functional models for HSH components are
required to select appropriate and compatible compo-
nents (Wollschlaeger et al., 2019). However, achiev-
ing interoperability is a complex problem (Vermesan
et al., 2014), resulting in high follow-up costs when
neglected in the design phase. As an example, NIST
reported annual costs of $ 15.8 billion for the U.S.
building industry (Gallaher et al., 2004). To detect
potential interoperability issues as early as possible,
it is necessary to include the semantics of information
exchanged by components in their functional mod-
els, enabling a conceptual interoperability assessment
at design time by comparing the resulting semantic
a
https://orcid.org/0000-0002-1101-0680
data types. While syntactical interoperability can be
achieved by middleware approaches and standardiz-
ing the data types of programming languages or the
payloads of communication technologies, semantic
information describing the actual meaning of data is
often neglected. This semantics of information in the
context of automated design processes for HSH will
be this paper’s object of investigation with the aim
to provide a modeling framework for semantic data
types. In this context, semantic data types are classes
of equal meaning of information. Subsequently, main
requirements for the framework will be discussed.
Despite the importance of semantic data types in
achieving semantic interoperability in both the de-
sign and operation phase of HSH, the semantics of
data is nowadays often not formally specified, so no
automated processing of their meaning is possible.
Even if some approaches offer a vocabulary of seman-
tic types that enable a basic annotation of semantics
(VDI 3813-2, 2011), these vocabularies are usually of
low expressiveness. The automated processing of se-
mantic information is limited to a comparison of data
type names only. Therefore, it is still an open prob-
lem to provide a high model expressiveness, leading
to REQUIREMENT I) explicability.
During the design process, semantic data types are
Wollschlaeger, B., Eichenberg, E. and Kabitzsch, K.
Explain Yourself: A Semantic Annotation Framework to Facilitate Tagging of Semantic Information in Health Smart Homes.
DOI: 10.5220/0008968901330144
In Proceedings of the 13th International Joint Conference on Biomedical Engineering Systems and Technologies (BIOSTEC 2020) - Volume 5: HEALTHINF, pages 133-144
ISBN: 978-989-758-398-8; ISSN: 2184-4305
Copyright
c
2022 by SCITEPRESS Science and Technology Publications, Lda. All rights reserved
133
relevant in two different levels of detail: firstly, they
are used to model an abstract system specification
without usually taking into account aspects of data
representation. Secondly, they are used for detailed
modeling of the required and provided data for spe-
cific components. These different levels of abstrac-
tion render it difficult to assess how well a specific
component fits to the abstract specification. In addi-
tion, the level of abstraction is fixed for existing ap-
proaches, i. e. it is not possible to use the same vo-
cabulary for abstract specification and detailed com-
ponent modeling. This leads to the open problem of
supporting different levels of details within the same
approach; resulting in REQUIREMENT II) comprehen-
siveness.
As the interdisciplinary domain of HSH is highly
diverse and dynamic, a modeling framework for an-
notating semantics to data types needs to be flexi-
ble and extensible. Existing vocabularies of semantic
types are usually not extensible, but rather fixed and
limited. Therefore, the open problem to be able to
account for future changes in the dynamic domain of
HSH leads to REQUIREMENT III) extensibility.
In order to meet the requirements outlined above,
the modeling framework developed by this paper will
use the concept of semantic annotations (shortly re-
ferred to as tags) in multiple dimensions encompass-
ing different aspects of semantics. All in all, this pa-
per proposes the following main contributions:
1. Proposal of an ontology structure for semantic an-
notation frameworks meeting requirements I) to
III).
2. Description of a systematic and reproducible
method that can be used to develop semantic an-
notation frameworks for different domains.
3. Development of an exemplary semantic annota-
tion framework for room automation aspects of
HSH that is extensible to further aspects of HSH.
This paper is structured as follows: The next sec-
tion discusses related work for HSH and semantic an-
notations of data. Section 3 extends a conceptual core
framework of HSH to provide context for semantic
annotations in assistance systems. Section 4 describes
the development of the proposed semantic annotation
framework for room automation aspects of HSH, in-
cluding a possible extension of the developed frame-
work to cover further aspects of HSH. The framework
is validated in Section 5 by discussing its potential use
in a variety of application areas. Finally, the paper is
summarized by Section 6, which also provides further
research areas.
2 STATE OF THE ART
2.1 Engineering of Health Smart Homes
The concept of HSH addresses the living environ-
ment of patients and aims at both improving the qual-
ity of life and increasing the safety of the occupants.
To achieve this, HSH builds upon smart home tech-
nology to combine technical equipment with health
care applications (Rialle et al., 2002; Maeder and
Williams, 2017). Consequently, HSH are the nexus of
domains such as smart home, ambient assisted living
and room automation technologies (Wollschlaeger
and Kabitzsch, 2019).
A conceptual core framework from
(Wollschlaeger and Kabitzsch, 2019), which is
depicted in Figure 1 in UML-notation, shows the
main entities and their relationships for HSH. The left
side is constituted by the entities of the requirements
view and defines the demands (User Requirements)
of the HSH Occupant. On the right side, the entities
of the components view model the HSH Assistance
System and its respective Assistance Components.
Thus, the HSH’s capabilities in providing assistance
for the occupant are defined. The concept Assistance
Function mediates the demands and the capabilities
by providing a shared vocabulary for both the user
requirements’ functional intentions and the assistance
system’s functionality.
Figure 1: Core concepts of the conceptual framework for
HSH, from (Wollschlaeger and Kabitzsch, 2019).
In order to achieve the high level of customiza-
tion required for assistance systems in HSH (Maeder
and Williams, 2017), computer-based support is nec-
essary. (Wollschlaeger and Kabitzsch, 2020) formally
defines the HSH engineering task as well as an ap-
proach for automated engineering of HSH. This ap-
proach is motivated by a prototype of an automated
engineering approach in the adjacent domain of room
automation (Dibowski et al., 2010). Functional mod-
els for components aimed to facilitate the design pro-
cess have been investigated in different levels of de-
tail (Dibowski and Kabitzsch, 2011), (Wollschlaeger
et al., 2019). Key vocabulary for functionality was the
German room automation standard VDI 3813 (VDI
3813-2, 2011), which introduces standard functional-
ity and information types available in room automa-
HEALTHINF 2020 - 13th International Conference on Health Informatics
134
tion systems on an abstract and technology-neutral
level. As representation for functionality, it defines
function blocks and the information required and pro-
vided by them. However, the semantic data types used
in the prototypes were limited to a fixed set.
2.2 Semantic Data Types and Tags
A previous literature analysis revealed that currently
there is no comprehensive standard that can be used
as a common knowledge base for functionalities and
data types in the whole HSH domain (Wollschlaeger
and Kabitzsch, 2019). However, when only consid-
ering the room automation aspects of HSH, the func-
tional standard VDI 3813 can be regarded as such a
common understanding of functionality and informa-
tion types. It defines a set of 46 semantic types, which
each are semantically labeled with one mnemonic
name consisting of two components hinting at the
type of information represented and its meaning(e. g.
A_SUN representing the angle of the sun’s position).
Thus, a coarse structure for attributing semantics to
the information is available; yet, the two components
are often not clearly delimitated and further details are
only mentioned as unstructured explanation text. The
validity of interoperability assessment based solely on
the data type names is therefore limited.
As a different approach, system information mod-
els provide means to formalize specific technical sys-
tem configurations. There are plenty of approaches
for building automation systems (Butzin et al., 2017)
and smart homes (Grassi et al., 2013), such as Do-
moML (Sommaruga et al., 2011), the SSN-Ontology
(Compton et al., 2012), DogOnt (Bonino and Corno,
2008), ThinkHome Ontology (Kofler et al., 2012),
AAL-Onto (Welge et al., 2015), or SAREF (Daniele
et al., 2015). They focus on the detailed modeling of
environment and context, but mostly not on health-
related aspects. Though these approaches provide
generic high-level views of HSH, they do not model
sufficient information to attribute semantics to infor-
mation for design purposes.
Similarly, abstract reference models such as the
UniversAAL platform (Tazari et al., 2012) provide a
conceptual framework for systems in general, but re-
main too coarse on the aspect of data type semantics.
The ISO/IEEE 11073 standards family (ISO/IEEE
11073-10101a, 2015) offers a detailed nomenclature
for health information, yet remains largely focused
on communication in a hospital setting. Middleware
platforms aim at translating data between different en-
tities with possibly heterogeneous data models. The
ESKAPE platform (Pomp et al., 2017) lifts this trans-
lation the level of data to the level of information by
offering means for semantic data integration. It en-
ables the integration of custom semantic models into
a dynamic semantic knowledge graph, thus enabling
querying of information agnostic of the specific data
formats. However, the platform provides no guid-
ance on which data should be semantically modeled
and how the creation of the custom semantic models
should be conducted, resulting in potentially incom-
plete and incompatible semantic models.
Another class of approaches for modeling the se-
mantics of data are semantic tagging approaches. The
most prominent example from the field of building au-
tomation is Project Haystack
1
, which aims at mod-
eling the semantics of building automation compo-
nents. To this end, more than 200 semantic annota-
tions (tags) are available as a list or as an ontology
(Charpenay et al., 2015). This enables to create a sys-
tem model that is organized along the hierarchies of
site, equipment and (data) point. The flexibility and
community-based approach of Haystack has inspired
further work in the domain of IoT, e. g. the extended
data model BACnet XD by the BACnet group (Butzin
et al., 2017), the KNX Information Model by the KNX
Association (Pelesic et al., 2016), or for integration of
IoT and building systems (Schachinger et al., 2017).
In order to improve the applicability of tagged sys-
tem models, BRICK (Balaji et al., 2016) introduced
a metadata schema for buildings aimed at enabling
applications such as model-predictive control or fault
detection and diagnosis. BRICK offers an ontology of
entities (Point, Equipment, Location, Measurement)
and their relationships in order to model building au-
tomation systems and components.
These approaches aim at facilitating building an-
alytics by adding semantic information to models of
building systems. While capturing the systems’ struc-
ture and metadata, they are focused on the operation
phase and do not intend to use the semantic informa-
tion in the design phase. In contrast to the available
coarse granularity of data semantics, design tasks re-
quire a higher level of expressiveness such as shown
by (Wollschlaeger et al., 2019) for interoperability as-
sessments.
2.3 Taxonomies, Ontologies and
Taxonomy Creation Methods
A taxonomy is an hierarchical categorization sys-
tem consisting of dimensions, which each can
have different values (characteristics). Borrowing
from(Nickerson et al., 2013), a taxonomy T can be
defined as
1
http://project-haystack.org/
Explain Yourself: A Semantic Annotation Framework to Facilitate Tagging of Semantic Information in Health Smart Homes
135
T = {D
i
, i = 1, . . . , n
| D
i
= {C
i j
, j = 1, . . . , k
i
; k
i
2}}
(1)
with D
i
being the dimensions and C
i j
their char-
acteristics. Ontologies extend the concept of tax-
onomies from an hierarchical categorization towards
a network of information and logical relationships.
Due to the relationships between the concepts, the
strict hierarchical structure of a taxonomy is not suf-
ficient for representing it. Instead, a knowledge graph
is required.
Taxonomies and ontologies are often used for
structuring concepts in a specific domain of interest.
A reproducible method for developing these struc-
tures promotes re-use of the categorizations. In the
field of Information Systems Research, however, sev-
eral analyses pointed out that most taxonomies are
developed in an ad hoc and thus non-reproducible
manner (Nickerson et al., 2013; Lösser et al., 2019).
In order to increase the rigor in taxonomy develop-
ment and to provide guidance for researchers dur-
ing the taxonomy design process, (Nickerson et al.,
2013) proposed a generic high-level method for tax-
onomy development. Their proposed method uses
meta-characteristics as a conceptual kernel and allows
for an iterative taxonomy design process offering both
a bottom-up (inductive) and a top-down (deductive)
approach (cf. Figure 2).
Figure 2: Method for Taxonomy Creation according to
(Nickerson et al., 2013).
With the flexibility of choosing both inductive as
well as deductive approaches, this taxonomy develop-
ment method fits for creating the semantic annotation
framework. This is due to the fact that on the one
hand, some semantic data types have been defined in
the domain (favoring the inductive approach) and on
the other hand, a vast conceptual knowledge is avail-
able (facilitating the deductive approach). The itera-
tive nature of the method allows for a combination of
both approaches to reach the best trade-off between
structuring and adhering to the existing types.
3 SEMANTIC DATA MODELS IN
HSH CONTEXT
In order to put semantic data types into context, a con-
ceptual framework of the assistance system aspects of
HSH will be used. Based upon the conceptual core
framework from (Wollschlaeger and Kabitzsch, 2019)
(cf. Figure 1) and the UniversAAL reference model
(Tazari et al., 2012), the concepts and relationships
of the assistance systems are depicted in Figure 3 in
UML notation.
Figure 3: Conceptual Model of Assistance Systems in HSH
context.
The classes on the left model Assistance
Component as structures for equipment, which
contains a software application, modeled by
Device Application. The software applica-
tion provides a certain functionality modeled by
Assistance Function. The classes on the right
side Communication Relation and Semantic
Data Type are used to model the interconnections
of assistance components in the assistance system.
More specifically, the assistance components are
communicating with each other in order to fulfill
their functionality. A communication relation models
one of the information exchanges for a set of “linked”
assistance components. Each communication relation
is used to exchange a specific type of information
between the assistance components’ software ap-
plications, modeled by its data type. On the other
hand, these software applications need to provide
information about their software interface. More
specifically, they need to model required data types
on the input side as well as provided data types on
the output side.
The key concept of interoperability can now be
investigated: the software applications exchanging in-
formation in the context of a specific communication
relation need to adhere to its semantic data type. More
specifically, the data types of the provided and the re-
quired side need to be compatible with each other.
HEALTHINF 2020 - 13th International Conference on Health Informatics
136
The types are said to be compatible if the provided
types are equal to or a subclass of the required types.
4 SEMANTIC ANNOTATION
FRAMEWORK
The following section shows the development of the
semantic annotation framework in more detail. First,
the overall structure of the framework is discussed.
Then, the taxonomy creation method of (Nickerson
et al., 2013) is applied and descriptions of the differ-
ent iterations and the decisions made in the taxonomy
creation process are provided. When describing the
taxonomy creation, we will use the numbers of the
different steps according to Figure 2 for reference.
4.1 Structuring Semantic Data
Annotations
The main idea for structuring the semantic annotation
framework is based on describing semantics along
several different information dimensions. This is mo-
tivated by different approaches of semantic system
modeling for building analytics, such as the Seman-
tic Sensor Network Ontology, the semantic tagging
approach Project Haystack, and the BRICK metadata
schema (cf. Section 2.2). Those approaches provide
detailed system models by taking entities and their
relationships into account. We aim to translate such
expressiveness to the semantic information modeling
by providing different aspects of semantics. Such a
composite semantic model allows for expressing in-
formation and relations in much more detail than se-
mantic models consisting of only one semantic label.
Figure 4: Model of the Semantic Annotation Framework.
Following the structuring approach outlined
above, Figure 4 depicts a model of the proposed
framework. A Semantic Data Type is composed
of several different Semantic Aspects, which each
are annotated with Semantic Tags. When consid-
ering the semantic annotation framework as a taxon-
omy, the aspects are taxonomy dimensions with the
different annotations making up the characteristics of
these dimensions. Since taxonomies are structurally
less complex than ontological knowledge graphs, we
start with a development process geared for taxon-
omy creation (Nickerson et al., 2013) and evaluate
the taxonomy’s expressiveness at each iteration in or-
der to decide whether an extension (e. g. by using the
parentTag relation in Figure 4) towards an ontology
structure is beneficial.
4.2 Meta-characteristics and Ending
Condition
At the beginning of the taxonomy creation pro-
cess, the Nickerson method requires to define meta-
characteristics and ending conditions for this process.
Meta-characteristics are used as the basis for choosing
the dimensions in the taxonomy. As the process itself
is iterative, the ending conditions are required to de-
termine, at which point the taxonomy creation process
may terminate, i. e. the resulting taxonomy fulfills the
intended goal (Nickerson et al., 2013).
For step 1, we choose meta-characteristics that re-
fer to the orthogonal aspects of i) which entity is de-
scribed, ii) in which context, and iii) using which real-
ization. The last meta-characteristic is closely related
to syntactic aspects of how information is encoded;
however, since it models semantic aspects, it will only
entail realization aspects on an abstract level. We de-
fine the meta-characteristics as follows (cf. Table 1):
Table 1: The meta-characteristics (MC) chosen in step 1 of
the taxonomy creation process.
ID NAME EXPLANATION
MC1 Entity What is the information
referring to?
MC2 Context In which context is the
information generated
and used?
MC3 Realization How is the information
encoded?
Several possible pre-defined ending conditions for
step 2 are defined by Nickerson, divided into objective
and subjective ending conditions (Nickerson et al.,
2013). The conditions depicted in Table 2 were se-
lected for the development process.
4.3 First Iteration
The first iteration starts with the decision, if the
top-down (conceptual-to-empirical) or bottom-up
(empirical-to-conceptual) approach should be used
(step 3). Since various domain knowledge is available
Explain Yourself: A Semantic Annotation Framework to Facilitate Tagging of Semantic Information in Health Smart Homes
137
Table 2: The ending conditions (ECO / ECS) chosen in step 2 of the taxonomy creation process.
ID NAME EXPLANATION
OBJECTIVE ENDING CONDITIONS
ECO1 Comprehensive
Modeling
Semantic data types of target domain are comprehensively modeled (all objects
have been examined)
ECO2 Objects stable No object was merged or split in the last iteration
ECO3 Important con-
cepts identified
No new dimensions or characteristics were added in the last iteration
ECO4 Concepts stable No dimensions or characteristics were merged or split in the last iteration
ECO5 Dimension
Uniqueness
Every dimension is unique and not repeated (i. e. there is no duplicate)
ECO6 Characteristic
Uniqueness
Every characteristic is unique within its dimension
SUBJECTIVE ENDING CONDITIONS
ECS1 Conciseness The number of dimensions limited to at most 7± 2
ECS2 Robustness Sufficient differentiation amongst the objects is feasible
ECS3 Comprehen-
siveness
REQUIREMENT II) All objects of interest can be classified
ECS4 Extensibility REQUIREMENT III) New dimensions / characteristics can be added easily
ECS5 Explicability REQUIREMENT I) The dimensions / characteristics are able to explain the objects
that may serve as a conceptual guideline for struc-
turing semantic models, we chose the conceptual-
to-empirical approach with the data types of the
VDI 3813 as the initial set of objects. At this point,
we have to restrict the objects under investigation to
the room automation aspects of HSH, as further as-
pects such as assistance technology still lack a com-
mon understanding of semantics (Wollschlaeger and
Kabitzsch, 2019). We envisage to broaden the per-
spective towards further aspects of HSH once the con-
ceptual structure has been consolidated. Section 4.6
demonstrates the framework’s extensibility by dis-
cussing health-related HSH examples.
Since this is the first iteration, step 4c conceptu-
alizes new dimensions and characteristics based on
the conceptual kernel of meta-characteristics. In or-
der to achieve an easily extensible taxonomy, we fol-
low the approach of the SSN-Ontology (Compton
et al., 2012) and deduct the two new dimensions FEA-
TURE OF INTEREST and PHYSICAL QUALITY from
MC1 Entity. Their characteristics can be determined
by investigating potential entities and properties in
a room. Entities involve equipment (climatisation,
contact, damper, drive, fan, lamella, lamp, sunblind,
valve, vav
2
), and physical entities (air, light, occu-
pant, sun, water), distinguishing if the entity can be
directly controlled by technical means (equipment) or
not (physical entity). On the other hand, each en-
tity possesses different properties, constituting a list
of PHYSICAL QUALITIES.
2
Variable Air Volume, a type of ventilation system
The second meta-characteristic MC2 Context is
used to infer two further dimensions LOCATION and
VARIABLE TYPE to model the information origin and
usage, respectively. The LOCATION dimension con-
tains characteristics describing the location type of
the information’s origin, namely indoor, outdoor, bms
(building management system), and equipment (if the
information is used in the technical systems only).
The VARIABLE TYPE dimension models the in-
tended usage of the contained information. Since the
processes in room automation may be modeled as
control loops, the VARIABLE TYPE dimension uses
characteristics classifying data based on its usage in a
standard control loop. Figure 5 depicts the different
characteristics that were identified using the interna-
tional electrotechnical vocabulary for control theory
(IEC 60050-351, 2013). The types of variables can
be differentiated into operating values (command and
setpoint), computed values (i. e. controller output) and
measured values (state and value).
Finally, meta-characteristic MC3 Realization al-
lows to infer abstract realization characteristics. The
dimension TRIGGER TYPE models that information
can be created by a manual human action (e. g. choos-
ing temperature set point or the push of a button) or by
algorithms in an automatic way (e. g. the blind posi-
tion following the movement of the sun). This distinc-
tion often carries further semantic information with
respect to prioritizing the commands, as most often
the command issued by humans can override auto-
matically generated commands.
In addition, the dimension REFERENCE TYPE
HEALTHINF 2020 - 13th International Conference on Health Informatics
138
models if a value is to be interpreted as an absolute
or a relative value. In case of relative values, a base
value is required in order to compute the actual value
to work with. This distinction is important for e. g.
setting the temperature set point, as most room con-
trol units only provide means to adjust the set point
within ±5K, while others allow a specific tempera-
ture as set point.
Finally, the dimension REPRESENTATION allows
to specify the general type of information encoding in
terms of the scale of measurement. It distinguishes
amongst binary, quantified, continuous, nominal, and
ordinal values. Nominal and ordinal values repre-
sent enumeration types with ordinal values addition-
ally featuring a partial order.
Having identified the initial set of dimensions and
characteristics, step 5c examines existing semantic
data types as empirical objects for these dimensions
and characteristics. The 46 types of the VDI 3813
were annotated semantically. If multiple semantic an-
notations for each dimension were possible, they were
assigned simultaneously. However, this strongly indi-
cates that the semantic type in question is ambiguous,
i. e. defined too vaguely as it can have multiple mean-
ings, preventing this type to be used in an interoper-
ability assessment.
With the results of the first iteration, the result-
ing vocabulary (step 6c) consists of the seven dimen-
sions and 53 characteristics. Different from Nicker-
sons original method, we put major emphasis on RE-
QUIREMENT III) extensibility (e. g. new equipment,
new considered physical entities, new forms of rep-
resentation, .. . ), so we do not eliminate dimensions
and characteristics that are not yet used, as long as
Figure 5: The different Variable Types (bold in boxes) in
a closed-loop control system. The functionalities are dis-
played as function blocks according to (VDI 3813-2, 2011).
they are potentially useful. As an example, the di-
mensions TRIGGER TYPE, REFERENCE TYPE and
REPRESENTATION are usually not specified at the ab-
stract level of the VDI 3813, but they can be used to
further model the semantics of specific component in-
terfaces (cf. (Wollschlaeger et al., 2019)). For this
reason, we did not eliminate these dimensions, but
keep them as extension points for more detailed mod-
eling. By allowing information dimensions to be un-
specified, subclass-relationships amongst the seman-
tic types can be inferred quite easily. This enables to
model semantic types with different levels of abstrac-
tion, e. g. more abstract types for system specification
and specific types for functional component modeling
(cf. REQUIREMENT II) comprehensiveness).
After the first iteration, step 7 tests if the ending
conditions have been met. From the objective ending
conditions, ECO3 is not met since new dimensions
and characteristics were added. As not all ending con-
ditions have been met, at least one more iteration is
needed.
4.4 Second Iteration
At the beginning of the second iteration in step 3, a de-
cision for the top-down or bottom-up approach needs
to be made. Since we identified several ambiguous
data types in iteration 1, we use the bottom-up ap-
proach in this iteration to investigate new and more
specific data types.
In step 4e, we identified missing data types that
will be added to the set of empirical objects. In to-
tal, 29 new data types have been identified, includ-
ing three new data types that were missing until now
(frost state, rain alarm, wind alarm). The further 26
data types resulted from introducing new, more spe-
cific data types for the ambiguities of D_ACT (con-
taining both date and time), L-types (describing lamp
activation or level), S-types (addressing sunblind or
lamella), as well as V_SET and V_STA (modeling ei-
ther drive position, fan rotation, or air flow). The for-
mer ambiguous data types were kept as “abstract data
types” and for compatibility with the standard.
In order to semantically annotate the new data
types, we adapted the vocabulary in step 5e. More
specifically, we added new characteristics for entities
(calendar, controller, hvac, room, shading), qualities
(frost, humidity, intrusion, pressure), and representa-
tion (complex). In addition, we renamed entity vav to
ventilation and restructured some of the qualities (az-
imuth to angle.azimuth, elevation to angle.elevation,
maintenance to maintenance.position, protection to
protection.position, mode_ventilation to mode) in or-
der to better grasp the real-world relationships. There
Explain Yourself: A Semantic Annotation Framework to Facilitate Tagging of Semantic Information in Health Smart Homes
139
was no need to adapt the dimensions themselves.
At the end of iteration 2 (step 6e), the semantic
annotation framework consists of 63 annotations in
seven categories. It was successfully used to model
75 semantic data types.
After the second iteration, step 7 tests if the end-
ing conditions have been met. In order to test the
robustness (ECS2) of the taxonomy, we modeled the
dimensions, characteristics and also data types in an
OWL ontology in order to use the reasoner for con-
sistency checks and subsumption analysis. We mod-
eled the data types as defined classes requiring an-
notations according to their respective characteristics.
As an example, we can define the room brightness
H_ROOM as a data type that contains information
about the FEATURE OF INTEREST light and its PHYS-
ICAL QUALITY illuminance, referring to an informa-
tion about an indoor (LOCATION) value (VARIABLE
TYPE). Usually, this value is represented as an ab-
solute value (REFERENCE TYPE). In E L
++
notation
(Baader et al., 2005), this yields:
H_ROOM DataType
u ( hasFeatureOfInterest.Light)
u ( hasQuality.Illuminance)
u ( hasLocation.Indoor)
u ( hasVariableType.Value)
u ( hasReferenceType.Absolute).
(2)
The reasoner confirmed the overall consistency
of the ontology and inferred a subsumption hier-
archy of types. Most of the hierarchical relations
were correct, but the following issues could be iden-
tified: First, the shading data types have no connec-
tion to each other; however, e. g. S_AUTO should
be a super type of S_AUTO_SBL (sunblind) and
S_AUTO_LML (lamella). Secondly, T_SUPPLY is
inferred to be a subclass of V_STA, which may con-
tain positions, flows, or rotations, but not tempera-
tures. This is due to the too lax definition of V_STA.
From the objective ending conditions, ECO3 is
not met, since new dimensions and characteristics
were added. ECO2 is also not met since some data
types were split. As not all ending conditions have
been met, at least one more iteration is needed.
4.5 Third Iteration
Again, the type of approach has to be defined in step
3 for this third iteration. In the previous iteration, two
issues were identified by using reasoning: On the one
hand, some relationships were missing (e. g. that the
data types for shading are related) and on the other
hand, some definitions were too broad, encompass-
ing non-related types (e. g. V_STA wrongly subsum-
ing T_SUPPLY). Since these main issues refer to the
semantic definition of existing data types, we choose
the top-down approach to adjust the characteristics.
In step 4c, we chose to adapt the generic room
model, which was used to specify the dimensions
FEATURE OF INTEREST and PHYSICAL QUALITY in
the first iteration, in order to add the missing relation-
ships. Therefore, we specified that both characteris-
tics sunblind and lamella are sub-classes of the shad-
ing system and that the climatisation and ventilation
characteristics are sub-classes of the hvac system.
Since the characteristics in one dimension of the
taxonomy are only lists, we included these hierarchi-
cal relations in the semantic annotation framework
ontology, but did not change the taxonomic structure.
At this point, the transition from taxonomy towards
ontology seems beneficial.
In step 5c, we modified the annotations for those
types that were defined too broadly. As an exam-
ple, the type V_STA had neither annotations from
the FEATURE OF INTEREST and PHYSICAL QUAL-
ITY dimensions in order to include its possible infor-
mation types (drive position, fan rotation, air flow).
We defined multiple annotations in previously empty
dimensions to include all sub-types while excluding
other non-related types. This was done for the types
V_STA and V_SET, D_ACT (to include the two pos-
sible properties date and time) and the L-Types (in-
clude two possible properties activation and level).
As we did not change the dimensions or charac-
teristics in this iteration, we do not need to revise the
taxonomy in step 6c. We added relationships between
the characteristics so that a reasoner can automatically
infer additional relations between the data types. By
doing so, we go beyond a taxonomic structure, which
is not able to capture relationships amongst the char-
acteristics. Instead, this renders the semantic frame-
work to an ontology that is largely based on the de-
veloped taxonomic structure.
At the end of the procedure, step 7 again checks
the ending conditions. Since we made no changes in
the semantic annotation vocabulary and only added
relationships in the ontology, the objective ending
conditions are met this time. By using the additional
relationships, the annotation framework could be in-
creased in robustness. All other subjective ending
conditions are also met, so that the taxonomy creation
process can be concluded.
The final and valid taxonomy for semantic data
types of the room automation aspects contains the di-
mensions and characteristics shown in Table 3.
HEALTHINF 2020 - 13th International Conference on Health Informatics
140
Table 3: The final semantic annotation framework for the room automation aspects of HSH.
Dimensions Characteristics
FEATURE OF
INTEREST
air calendar climatisation contact controller damper
drive fan hvac lamella lamp light
occupant room shading sun sunblind valve
ventilation weather
PHYSICAL
QUALITY
activation angle.azimuth angle.elevation date dewpoint flow
frost illuminance intrusion level maint.pos mode
position precipitation presence pressure protect.pos quality
rotation scene temperature time velocity
LOCATION bms equipment indoor outdoor
VARIABLE TYPE command computed setpoint state value
TRIGGER TYPE automatic manual
REFERENCE TYPE absolute relative
REPRESENTATION binary complex continuous nominal ordinal quantified
4.6 Extension Capability towards
Remaining HSH Aspects
As there are no semantic standards for further as-
pects of HSH yet, we cannot create a holistic semantic
framework for HSH at this moment. However, we can
hint at how such a framework would look like due to
the extensible nature of the developed framework for
room automation.
To include aspects such as health care and as-
sistance systems into the semantic annotation frame-
work, further iterations of the Nickerson method may
extend the characteristics. Once a common under-
standing of further HSH functionality has been es-
tablished, each of these functions can be investigated
with respect to its required and provided information.
These types of information would constitute a new set
of semantic data types that can be annotated with the
framework proposed in this paper.
With health being a major part of the missing HSH
aspects, further characteristics of the occupant need
to be added. This may include the body’s height and
weight as well as vital parameters such as pulse, blood
pressure, body temperature, breathing rate. To incor-
porate e. g. chronic diseases, closely related charac-
teristics like blood sugar level or HbA1c value for di-
abetes type 2 might be added, too.
For dementia patients with wandering behavior, a
“tracking system” might be a useful functionality for
a HSH to prevent the patients getting lost. In this case,
the functionality would involve exchanging informa-
tion about the occupants position (for which annota-
tions already exist), which could also be specialized
to include the GPS position components latitude and
longitude. In case of the functionality “dietary as-
sistance”, information related to food are important,
more specifically its type and the amount consumed.
Similarly, the functionality “medication reminder” is
processing medication information regarding its type
and amount. This is combined with some informa-
tion regarding the day time or specified as a rate. As
a final example, some assistance systems are able to
identify states of emergency based on consumption
data from energy and water meters. This can be in-
corporated by the FEATURES OF INTEREST energy
and water as well as the PHYSICAL QUALITY anno-
tations consumption.current and consumption.total.
By discussing several examples from the
assistance- and health-related aspects of HSH, it
could be shown that the proposed framework is
extensible towards new semantic data types from the
HSH domain. New characteristics will be necessary
to account for specific aspects of HSH. However, it
can be expected that the structure of the framework’s
dimensions is expressive and robust, so most likely
no changes will be required here.
5 APPLICATION AREAS AND
VALIDATION
In order to validate that the proposed method for cre-
ating a semantic annotation framework has produced
a valid result, this section will discuss the applicabil-
ity of the resulting framework based on several appli-
cation areas. For each application area, we will pro-
vide an example that illustrates how the annotation
framework facilitates such applications.
Firstly, the annotation framework enables a con-
ceptual consistency check of established semantic
types due to its expressive semantic model. As has
been discussed in Section 4.3, we were able to de-
tect ambiguities in the established standard VDI 3813.
Explain Yourself: A Semantic Annotation Framework to Facilitate Tagging of Semantic Information in Health Smart Homes
141
The most important ambiguities were the data types
for lamp control missing a distinction between
switching (activation) and dimming (level) lamps, the
types for shading control not specifying whether
sunblind or lamella or both are controlled and
V_SET and V_STA, which each could represent three
completely different meanings.
Secondly, the structure of the framework allows
for a seamless semantic modeling from abstract spec-
ification to detailed component models. In context of
automated design approaches for HSH this means that
by applying the proposed framework a consistent ap-
proach in semantic data modeling can be used. De-
pending on the number of dimensions used for seman-
tic specification, the information type can be speci-
fied with varying level of abstraction. While informa-
tion types in system specifications on an abstract level
might only contain core aspects, independent of real-
ization details, a detailed functional model of an as-
sistance component may feature all available dimen-
sions to model the semantic of its exchanged data as
precisely as possible. Since both cases use the same
structure, a relation between more abstract and very
specific information types can be easily determined.
As an example, a system specification might in-
dicate that a functionality temperature controller re-
quires a temperature setpoint on the one hand and the
current temperature on the other hand. Thus, both
data types would be modeled as air (FEATURE OF IN-
TEREST) temperature (PHYSICAL QUALITY) indoor
(LOCATION). Additionally, the temperature setpoint
would be tagged with the setpoint annotation in the
VARIABLE TYPE dimension, while the current tem-
perature would be tagged with the value annotation.
A device implementing such a temperature con-
troller functionality might now additionally provide
semantic annotations for its interface. If the tempera-
ture setpoint is expected to be an offset value, it could
add the relative annotation to the REFERENCE TYPE
dimension. On the other hand, if it expects a specific
temperature value as setpoint, the annotation absolute
would be more appropriate. This additional level of
detail is vital to be able to detect a mismatch between
the sender of the setpoint and the expected seman-
tic of the data. If the sender is a room control unit
with a rotary switch for determining the setpoint off-
set, it would not be compatible with a temperature
controller expecting an absolute setpoint value.
Thirdly, as was hinted at by the example above,
the proposed framework allows for an improved in-
teroperability assessment by lifting the assessment
from a mere comparison of names to the level of ex-
pressive semantics and subsumption hierarchies. For
the temperature controller example above, instead
of comparing the semantic types T_SETPOINT and
T_SETPOINT, the more detailed versions (air, tem-
perature, indoor, setpoint, relative) and (air, temper-
ature, indoor, setpoint, absolute) can be compared.
Only this detailed comparison enables to spot inter-
operability issues when comparing the previous se-
mantic names of the data types, issues would not have
been predicted and only noticed after installation, in-
curring high revision costs.
The downside of using a subsumption hierarchy
instead of a name-based interoperability comparison
is the more difficult interoperability assessment com-
pared to string comparisons. The effect of using a
logical reasoner for interoperability assessment still
needs to be investigated more closely; however, a
component-wise interoperability assessment that in-
vestigates each dimension independently for interop-
erability could be implemented as a trade-off. As this
would involve several comparisons of strings, its per-
formance is expected to lie between single string com-
parison and logical reasoning. Since it would work
on a taxonomic structure only, a loss of expressive-
ness would be traded for a better performance. In
the future, the structure of the used semantic annota-
tion framework could be investigated to determine the
most efficient interoperability assessment algorithm:
if the annotations form a taxonomy, the component-
wise algorithm would be preferred, whereas logical
reasoning is required if the framework’s structure can
only be represented as an ontology.
Lastly, the detailed semantic specification of the
proposed framework allows for more sophisticated
analyses of semantic data types. This new depth of
understanding the semantics of a data type may be
used in future to make the component model speci-
fication process more efficient and robust. This pro-
cess consists of component manufacturers specifying
a functional model of their components. Until now,
they need to specify both the component’s function-
ality and the semantics of its interface independently,
resulting in a labor-intensive process with a high er-
ror probability. Furthermore, they are restricted to
a fixed list of semantic data types. If no exactly fit-
ting data type is available, they need to resort to the
best fit, thereby increasing the modeling error. By us-
ing the proposed semantic framework, the vocabulary
of available data types can be expanded strongly. If
none of the pre-specified data types is fitting, new data
types may be easily created by specifying the different
dimensions as it seems appropriate. Unlike assigning
the semantics to data types based on their names only,
newly created data types are instantly understandable
as the annotation framework provides a high degree
of explicability.
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On the other hand, the detailed semantic under-
standing of the data types can be used for suggestion
mechanisms. Instead of choosing a data type amongst
a list or manually specifying each dimension sepa-
rately, the knowledge base of functionalities and their
semantic interface can be used to automatically infer
and suggest possible data types based on the already
specified functionalities. This suggestion mechanism
can also be applied in the other direction, suggesting
possible functionalities based on the already seman-
tically annotated component interface. Such sugges-
tion mechanisms thus connect the previously indepen-
dent aspects in the modeling process.
6 CONCLUSIONS
In this paper, we proposed an extensible semantic
annotation framework that is able to add a signif-
icant level of semantic expressiveness to informa-
tion types exchanged in information systems such
as health smart homes. We applied a well-adopted
method for taxonomy creation to end up with a basic
structure, featuring seven dimensions and 63 charac-
teristics for semantic annotations. Afterwards, it was
extended to an ontology by introducing relationships
between the annotations, which allows the use of au-
tomated reasoning to infer relations between the mod-
eled data types. Since there are currently no common
vocabularies of functionality or semantic data types
for HSH as a whole, all its aspects could not yet be
included in the semantic framework. While it is re-
stricted to room automation aspects of HSH, 75 data
types of the VDI 3813 could be successfully modeled.
Furthermore, the feasibility of extending the seman-
tic framework to encompass missing aspects could be
demonstrated in Section 4.6 by adding new annota-
tions while preserving the general framework struc-
ture. This fulfills REQUIREMENT III) extensibility).
With its aspect-oriented approach and the defi-
nition of different dimensions of semantic annota-
tions, the approach is able to specify semantics in de-
tail and to meet REQUIREMENT I) explicability, sur-
passing the expressiveness capabilities of using mere
data type names to encode semantics. Since multi-
ple dimensions can be taken into account, the frame-
work also allows for a seamless semantic data model-
ing from abstract specification to detailed component
modeling, starting from a few dimensions to fully en-
compass all aspects of semantic data as demanded by
REQUIREMENT II) comprehensiveness).
We demonstrated how different applications are
facilitated by the proposed semantic annotation
framework namely, it enables a consistency check
on established semantic types, it improves the qual-
ity of interoperability assessments, and it lays the
foundation for streamlining the process of specifying
semantic models for automation components by en-
abling auxiliary suggestion functionalities.
As next steps, we intend to put the semantic anno-
tation framework into action by further investigating
the mentioned application areas. Improved interop-
erability assessment and support functions for model
specification seem to be the most promising applica-
tions as of now. Furthermore, once a consolidation of
functionality and data types is achieved for the whole
domain of HSH, we plan to extend the framework so
that is encompasses HSH as a whole. In order to in-
tegrate the semantic annotation framework with exist-
ing tagging approaches, ontology matching and merg-
ing approaches might be a viable tool to consolida-
tion of interdisciplinary semantic vocabularies (e. g.
the nomenclature of health informatics provided by
the IEEE 11073).
We consider the increased semantic expressive-
ness offered by the annotation framework as vital for
increasing the degree of automation of the design pro-
cess of HSH and as an enabler for an increased pro-
liferation of assistance technology applications in the
future.
ACKNOWLEDGEMENTS
The work for this paper was funded by the European
Social Fund and the Free State of Saxony (Grant no.
100310385). The authors would also like to offer spe-
cial thanks to Lena Otto and the other members of the
junior research group Care4Saxony for their valuable
feedback on the manuscript.
REFERENCES
Baader, F., Brandt, S., and Lutz, C. (2005). Pushing the EL
envelope. In IJCAI - Int. Joint Conf. on AI, pages 364–
369.
Balaji, B., Bhattacharya, A., Fierro, G., Gao, J., Gluck, J.,
Hong, D., Johansen, A., Koh, J., Ploennigs, J., Agar-
wal, Y., Berges, M., Culler, D., Gupta, R., Kjærgaard,
M. B., Srivastava, M., and Whitehouse, K. (2016).
Brick: Towards a Unified Metadata Schema For Build-
ings. In Proceedings of the 3rd ACM International
Conference on Systems for Energy-Efficient Built Envi-
ronments, BuildSys ’16, pages 41–50, New York, NY,
USA. ACM.
Bonino, D. and Corno, F. (2008). DogOnt - Ontology Mod-
eling for Intelligent Domotic Environments. In Sheth,
A., Staab, S., Dean, M., Paolucci, M., Maynard, D.,
Finin, T., and Thirunarayan, K., editors, The Semantic
Explain Yourself: A Semantic Annotation Framework to Facilitate Tagging of Semantic Information in Health Smart Homes
143
Web - ISWC 2008, pages 790–803, Berlin, Heidelberg.
Springer Berlin Heidelberg.
Butzin, B., Golatowski, F., and Timmermann, D. (2017).
A survey on information modeling and ontologies in
building automation. In IECON 2017 - 43rd Annual
Conference of the IEEE Industrial Electronics Society,
pages 8615–8621.
Charpenay, V., Käbisch, S., Anicic, D., and Kosch, H.
(2015). An ontology design pattern for IoT device tag-
ging systems. In 2015 5th International Conference on
the Internet of Things (IOT), pages 138–145.
Compton, M., Barnaghi, P., Bermudez, L., García-Castro, R.,
Corcho, O., Cox, S., Graybeal, J., Hauswirth, M., Hen-
son, C., Herzog, A., Huang, V., Janowicz, K., Kelsey,
W. D., Phuoc, D. L., Lefort, L., Leggieri, M., Neuhaus,
H., Nikolov, A., Page, K., Passant, A., Sheth, A., and
Taylor, K. (2012). The SSN ontology of the W3C se-
mantic sensor network incubator group. Journal of Web
Semantics, 17:25 – 32.
Daniele, L., den Hartog, F., and Roes, J. (2015). Study on se-
mantic assets for smart appliances interoperability: D-
S4: Final report. European Commission, Brussels.
Dibowski, H. and Kabitzsch, K. (2011). Ontology-based de-
vice descriptions and device repository for building au-
tomation devices. EURASIP Journal on Embedded Sys-
tems, 2011:3:1–3:17.
Dibowski, H., Ploennigs, J., and Kabitzsch, K. (2010). Auto-
mated design of building automation systems. IEEE
Transactions on Industrial Electronics, 57(11):3606–
3613.
Gallaher, M., O’Connor, A., Dettbarn, J., and Gilday, L.
(2004). Cost Analysis of Inadequate Interoperability
in the U.S. Capital Facilities Industry. techreport, Na-
tional Institute of Standards and Technology.
Grassi, M., Nucci, M., and Piazza, F. (2013). Ontolo-
gies for smart homes and energy management: An
implementation-driven survey. In 2013 Workshop on
Modeling and Simulation of Cyber-Physical Energy
Systems (MSCPES), pages 1–3.
Haux, R., Koch, S., Lovell, N. H., Marschollek, M.,
Nakashima, N., and Wolf, K.-H. (2016). Health-
enabling and ambient assistive technologies: Past,
present, future. Yearb Med Inform, Suppl. 1(Suppl
1):76–91. 27362588[pmid].
IEC 60050-351 (2013). International electrotechnical vocab-
ulary - Part 351: Control technology.
ISO/IEEE 11073-10101a (2015). Health informatics – Point-
of-care medical device communication Part 10101:
Nomenclature Amendment 1: Additional Definitions.
Kofler, M. J., Reinisch, C., and Kastner, W. (2012). A se-
mantic representation of energy-related information in
future smart homes. Energy and Buildings, 47:169
179.
Lösser, B., Oberländer, A. M., and Rau, D. (2019). Taxon-
omy Research in Information Systems: A Systematic
Assessment. In Proceedings of the 27th European Con-
ference on Information Systems (ECIS), Stockholm and
Uppsala, Sweden.
Maeder, A. J. and Williams, P. A. H. (2017). Health smart
homes: New challenges. Studies in health technology
and informatics, 245:166–169.
Nickerson, R. C., Varshney, U., and Muntermann, J. (2013).
A method for taxonomy development and its applica-
tion in information systems. European Journal of In-
formation Systems, 22(3):336–359.
Pelesic, I., Fernbach, A., Granzer, W., and Kastner, W.
(2016). Semantic Integration in Building Automation
A Case Study for KNX , oBIX and Semantic Web Ap-
plications. In Proceedings of the KNX Scientific Con-
ference.
Pomp, A., Paulus., A., Jeschke., S., and Meisen., T. (2017).
Eskape: Information platform for enabling semantic
data processing. In Proceedings of the 19th Inter-
national Conference on Enterprise Information Sys-
tems - Volume 2: ICEIS,, pages 644–655. INSTICC,
SciTePress.
Rialle, V., Duchene, F., Noury, N., Bajolle, L., and Demon-
geot, J. (2002). Health "Smart" Home: Information
Technology for Patients at Home. Telemedicine Jour-
nal and e-Health, 8(4):395–409. PMID: 12626109.
Schachinger, D., Fernbach, A., and Kastner, W. (2017).
Modeling framework for IoT integration of build-
ing automation systems. at-Automatisierungstechnik,
65(9):630–640.
Sommaruga, L., Formilli, T., and Rizzo, N. (2011). Do-
moML: An Integrating Devices Framework for Ambi-
ent Intelligence Solutions. In Proceedings of the 6th In-
ternational Workshop on Enhanced Web Service Tech-
nologies, WEWST ’11, pages 9–15, New York, NY,
USA. ACM.
Tazari, M.-R., Furfari, F., Fides-Valero, Á., Hanke, S., Höft-
berger, O., Kehagias, D. D., Mosmondor, M., Wichert,
R., and Wolf, P. (2012). The universAAL Reference
Model for AAL. In Handbook of Ambient Assisted Liv-
ing.
VDI 3813-2 (2011). Building automation and control sys-
tems (BACS). Room control functions (RA functions).
Vermesan, O., Friess, P., et al. (2014). Internet of things-
from research and innovation to market deployment,
volume 29. River publishers Aalborg.
Welge, R., Busch, B.-H., Kabitzsch, K., Laurila-Dürsch, J.,
Heusinger, S., Lipprandt, M., Eichelberg, M., Eichen-
berg, E., Engelien, H., Gök, M., Moritz, G., Hein, A.,
and Dutz, T. (2015). AAL-Onto: A Formal Represen-
tation of RAALI Integration Profiles. In Wichert, R.
and Klausing, H., editors, Ambient Assisted Living: 7.
AAL-Kongress 2014 Berlin, Germany, January 21-22,
2014, pages 89–102. Springer International Publishing,
Cham.
Wollschlaeger, B., Eichenberg, E., and Kabitzsch, K. (2019).
Switching to a holistic perspective on semantic com-
ponent models in building automation tapping the
full potential of automated design approaches. IOP
Conference Series: Earth and Environmental Science,
323:012047.
Wollschlaeger, B. and Kabitzsch, K. (2019). Navigating the
Jungle of Assistance Systems: A Comparison of Stan-
dards for Assistance Functionality. In Proceedings of
the 12th International Joint Conference on Biomedi-
cal Engineering Systems and Technologies - Volume 5:
HEALTHINF, pages 359–366. INSTICC, SciTePress.
Wollschlaeger, B. and Kabitzsch, K. (2020). Automated En-
gineering for Health Smart Homes: Find a Way in the
Jungle of Assistance Systems (accepted). Studies in
health technology and informatics.
HEALTHINF 2020 - 13th International Conference on Health Informatics
144