<!DOCTYPE article PUBLIC "-//NLM//DTD JATS (Z39.96) Journal Archiving and Interchange DTD v1.0 20120330//EN" "JATS-archivearticle1.dtd">
<article xmlns:xlink="http://www.w3.org/1999/xlink">
  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Managing the Architecture Complexity of Intelligent Digital Systems</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Kurt Sandkuhl</string-name>
          <email>kurt.sandkuhl@uni-rostock.de</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Alfred Zimmermann</string-name>
          <email>Alfred.Zimmermann@Reutlingen-University.de</email>
          <xref ref-type="aff" rid="aff2">2</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Rainer Schmidt</string-name>
          <email>rainer.schmidt@hm.edu</email>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Dierk Jugel</string-name>
          <email>Jugel@hhz.de</email>
          <xref ref-type="aff" rid="aff2">2</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Michael Möhring</string-name>
          <email>michael.moehring@hm.edu</email>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Institute of Computer Science, University of Rostock</institution>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>Munich University of Applied Sciences</institution>
          ,
          <country country="DE">Germany</country>
        </aff>
        <aff id="aff2">
          <label>2</label>
          <institution>Reutlingen University</institution>
          ,
          <addr-line>Reutlingen</addr-line>
          ,
          <country country="DE">Germany</country>
        </aff>
      </contrib-group>
      <fpage>114</fpage>
      <lpage>126</lpage>
      <abstract>
        <p>Digital technologies are main strategic drivers for digitalization and offer ubiquitous data availability, unlimited connectivity, and massive processing power for a fundamentally changing business. This leads to the development and application of intelligent digital systems. The current state of research and practice of architecting digital systems and services lacks a solid methodological foundation that fully accommodates all requirements linked to efficient and effective development of digital systems in organizations. Research presented in this paper addresses the question, how management of complexity in digital systems and architectures can be supported from a methodological perspective. In this context, the current focus is on a better understanding of the causes of increased complexity and requirements to methodological support. For this purpose, we take an enterprise architecture perspective, i.e. how the introduction of digital systems affects the complexity of EA. Two industrial case studies and a systematic literature analysis result in the proposal of an extended Digital Enterprise Architecture Cube as framework for future methodical support.</p>
      </abstract>
      <kwd-group>
        <kwd>Architecture Complexity</kwd>
        <kwd>Digital Enterprise Architecture</kwd>
        <kwd>Digital Systems</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>-</title>
      <p>
        Digital transformation is the current dominant type of business transformation [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ],
[
        <xref ref-type="bibr" rid="ref3">3</xref>
        ] having IT both as a technology enabler and as a strategic driver. Digital technologies
are main strategic drivers [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ] for digitalization because digital technologies are
changing the way, how business is conducted and have the potential to disrupt existing
businesses. SMACIT defines in [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ] the strategic core of digital technologies, with
abbreviations for Social, Mobile, Analytics, Cloud, the Internet of Things. From today’s view
some scholars argue that we have to enlarge this technological core by artificial
intelligence and cognition, biometrics, robotics, blockchain and edge computing. Digital
technologies deliver three core capabilities for a fundamentally changing business [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ]:
ubiquitous data availability, unlimited connectivity, and massive processing power.
      </p>
      <p>
        This leads to the development and application of intelligent digital systems (see
section 3). We see great future prospects for digital systems with artificial intelligence (AI)
[
        <xref ref-type="bibr" rid="ref4">4</xref>
        ], [
        <xref ref-type="bibr" rid="ref5">5</xref>
        ], with the potential to contribute to improvements in many areas of work and in
society through digital technologies. We understand digitalization based on new
methods and technologies of artificial intelligence as a complex integration of digital
services, products and related systems. Classical industrial products are limited in their
change and configuration possibilities once deployed to users. On the contrary,
digitized products are more dynamic [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ]. They contain both hardware and software with
(cloud-)services. They can be upgraded via network connections. In addition, their
functionality can be extended or adapted using external services. Therefore, the
functionality of products is dynamic and can be adapted to changing requirements and
hitherto unknown customer needs. In particular, it is possible to create digital products and
services step-by-step or provide temporarily unlockable functionalities. So, customers
whose requirements are changing can add and modify service functionality without
hardware modification.
      </p>
      <p>
        Unfortunately, the current state of art in research and practice of architecting digital
systems and services lacks a solid methodological foundation as the established
methodical approaches do not fully accommodate requirements, e.g., caused by
product-IT integration [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ] or digital manufacturing. The long-term aim of our work is
to contribute to an efficient and effective development of digital systems in
organizations. Our conjecture is the managing complexity will be an important aspect of
reaching this aim. Therefore, our current research focuses on the main research question:
How can management of complexity in digital systems and architectures be supported
from a methodological perspective?
      </p>
      <p>In our work, we take an enterprise architecture (EA) perspective (see section 3), i.e.
we do not consider single products, applications or business services but the overall
change in business architecture, application architecture and technology architecture of
an enterprise. As a first step for investigating the above research question, this paper
focuses on a better understanding of the causes of increased complexity and
requirements to methodological support. More concrete, our focus in this paper is to
investigate how the introduction of digital systems affects the complexity of EA.</p>
      <p>The rest of the paper is structured as follows. Section 2 introduces the research
methods applied in the paper. Section 3 summarizes the background for our work from EA
and digital systems, and discusses related work on architecture complexity. Section 4
presents two industrial case studies of digital system development. Section 5
investigates the effects on architecture complexity in the case studies, Section 6 presents the
extended Digital Enterprise Architecture Cube as a result of the case study analysis.
Section 7 summarizes our findings and discusses future work.
2</p>
    </sec>
    <sec id="sec-2">
      <title>Research Approach</title>
      <p>
        This paper is part of a research process aiming to provide methodological and tool
support for managing architecture complexity. It follows the five stages of Design Science
research [
        <xref ref-type="bibr" rid="ref23">23</xref>
        ], namely, problem explication, requirements definition, design and
development of the design artifact, demonstration, as well as evaluation. This study concerns
the first step, the problem explication including confirmation of problem relevance.
This part of our research started from the research question motivated and presented in
section 1: RQ: In the context of digital transformation, how does the introduction of
digital systems affect the complexity of enterprise architectures?
      </p>
      <p>The research method used for working on this research question is a combination of
literature study and descriptive case study. Based on the research question, we analyzed
the literature in these areas. The purpose of the analysis was to find work from
enterprise architecture management or digital systems that explicitly addresses changes in
architecture complexity when introducing artificial intelligence (see section 3.3).</p>
      <p>
        As the literature analysis did not produce relevant papers, we identified industrial
cases of AI introduction into the EA and performed qualitative case studies in order to
obtain relevant and original data (see section 4). Qualitative case study is an approach
to research that facilitates exploration of a phenomenon within its context using a
variety of data sources. This ensures that the subject under consideration is explored from
a variety of perspectives which allows for multiple facets of the phenomenon to be
revealed and understood. Within the case studies, we used two different perspectives,
which at the same time represent sources of data: we analyzed the project
documentation and we investigated the enterprise architecture, business process and software
design models. Yin [
        <xref ref-type="bibr" rid="ref24">24</xref>
        ] differentiates case studies explanatory, exploratory and
descriptive. The case studies in section 4 are considered descriptive, as they describe the
phenomenon of initiating DT development and the real-life context in which it occurs.
      </p>
      <p>Based on the results of the case studies, we argue that additional perspectives and
architecture views would be beneficial for managing architecture complexity.
3
3.1</p>
    </sec>
    <sec id="sec-3">
      <title>Background and Related Work</title>
      <sec id="sec-3-1">
        <title>Digital Enterprise Architectures</title>
        <p>
          The term enterprise architecture (EA) in general denotes the fundamental conception
or representation of an enterprise—as embodied in its main elements and
relationships—in an appropriate model. Enterprise architecture management (EAM) provides
an approach for a systematic development of an enterprise’s architecture in line with
its goals by performing planning, transforming, and monitoring functions. The reasons
for applying EAM are manifold, such as supporting the alignment of IT to business
goals or the reduction of complexity. In general, an EA captures and structures all
relevant components for describing an enterprise, including the processes used for
development of the EA as such [
          <xref ref-type="bibr" rid="ref7">7</xref>
          ]. Research activities in EAM are manifold. The literature
analysis included in [
          <xref ref-type="bibr" rid="ref8">8</xref>
          ] shows that elements of EAM [
          <xref ref-type="bibr" rid="ref9">9</xref>
          ], process and principles [
          <xref ref-type="bibr" rid="ref10">10</xref>
          ],
and implementation drivers and strategies [
          <xref ref-type="bibr" rid="ref11">11</xref>
          ] are among the frequently researched
subjects. Furthermore, there is work on architecture analysis [
          <xref ref-type="bibr" rid="ref12">12</xref>
          ] and decision making
based on architectures [
          <xref ref-type="bibr" rid="ref13">13</xref>
          ], which so far does not include AI-related decisions.
        </p>
        <p>
          Digital enterprise architecture [
          <xref ref-type="bibr" rid="ref14">14</xref>
          ], [
          <xref ref-type="bibr" rid="ref15">15</xref>
          ] provides a comprehensive view on
integrated elements from both business and IT for implementing digital transformation
strategies including digital systems and services (see next section). More precisely we
integrate configurations of stakeholders (roles, accountabilities, structures, knowledge,
skills), business and technical processes (workflows, procedures, programs), and
technology (infrastructure, platforms, applications) to execute digital strategies and
compose value-proposition-oriented digital products and ser-vices. Digital business design
covers not simple business restructuring or just IT architecture. Digital business is
foremost an aspect that is currently in use and constantly changing.
3.2
        </p>
      </sec>
      <sec id="sec-3-2">
        <title>Intelligent Digital Systems and Services</title>
        <p>
          From today’s view, probably no digital technology is more exciting than artificial
intelligence offering massive automation capabilities for intelligent digital systems and
services. Artificial intelligence (AI) [
          <xref ref-type="bibr" rid="ref4">4</xref>
          ], [
          <xref ref-type="bibr" rid="ref16">16</xref>
          ] is often used in conjunction with other
digital technologies, like analytics, ubiquitous data, the Internet of Things, cloud
computing, and unlimited connectivity. Fundamental capabilities of AI concern automatic
generated solutions from previous useful cases and solution elements, inferred from
causal knowledge structures like rules and ontologies, and from learned solutions based
on data analytics with machine learning and deep learning with neural networks.
        </p>
        <p>
          Artificial intelligence receives a high degree of attention due to recent progress in
several areas such as image detection, translation and decision support [
          <xref ref-type="bibr" rid="ref4">4</xref>
          ]. It enables
interesting new business applications such as predictive maintenance, logistics
optimization and improving customer service management. Artificial intelligence supports
decision-making in many business areas. Most companies expect to gain competitive
advantage from AI. Today's advances in the field of artificial intelligence [
          <xref ref-type="bibr" rid="ref17">17</xref>
          ], [
          <xref ref-type="bibr" rid="ref18">18</xref>
          ]
have led to a rapidly growing number of intelligent services and applications. The joint
development of competencies via intelligent digital systems promises great value for
science, economy and society and is driven by data, calculations and advances in
algorithms for machine learning, perception and cognition, planning and natural language.
        </p>
        <p>
          Artificial intelligence is often characterized as impersonal: From this point of view,
intelligent systems operate completely automatically and independently of human
intervention. The public discourse on autonomous algorithms working on passively
collected data contributes to this view. However, this perspective of huge automation
obscures the extent to which human work necessarily forms the basis for modern AI
systems [
          <xref ref-type="bibr" rid="ref16">16</xref>
          ] and makes them possible in the first place. The human element of intelligent
systems includes tasks like optimizing knowledge representations, developing
algorithms, collecting and tagging data, and deciding what to model and how to interpret
the results. The study of artificial intelligence from a human-centric perspective
requires a deep understanding of the role of human ethics, human values and customs,
and the practices and preferences for development and interaction with intelligent
systems. With the success of AI, new concerns and challenges regarding the impact of
these technologies on human life are emerging. These include issues of security and
trustworthiness of AI technologies in digital systems, the fairness and transparency of
systems, and the conscious and unintended impact of AI on people and society.
        </p>
        <p>
          Combining product components of hardware and software with cloud-provided
intelligent services enable new ways of intelligent interaction with customers, as in [
          <xref ref-type="bibr" rid="ref19">19</xref>
          ].
The lifecycle of digitized products is extended by intelligent services. An example is
Amazon Alexa, which groups a physical device having a micro-phone and speaker with
services, called Alexa skills. Users can enhance Alexa's capabilities with skills which
are similar to apps. The set of Alexa skills is dynamic and can be tailored to the
customer’s requirements during runtime. Alexa enable voice interaction, music playback,
to-do lists, set alarms, stream podcasts, play audio books and provide weather, traffic,
sports, and other real-time information such as news. Using programmed skills Alexa
can also connect and control intelligent products and devices.
3.3
        </p>
      </sec>
      <sec id="sec-3-3">
        <title>Literature Analysis on Architecture Complexity</title>
        <p>
          As part of our research work, we performed a literature analysis that aimed at
identifying research work from enterprise architecture management or digital systems that
explicitly addresses changes in architecture complexity when introducing artificial
intelligence. In order to identify relevant work, we decided to perform a systematic literature
review (SLR) based on the procedure proposed by Kitchenham [
          <xref ref-type="bibr" rid="ref22">22</xref>
          ] with the main
research question What published work exists on architecture complexity of digital
systems, artificial intelligence and in digital transformation?
        </p>
        <p>The literature source examined was Scopus, which includes most publications from
the AIS electronic library (AISeL), IEEE Xplore and Springer. Publications with
significant impact on research should reach one of these major outlets. Starting from the
research question, we constructed a search query for Scopus by including different
keyword combinations and synonyms. The final search queries are shown in Table 1.</p>
        <p>
          The search results show that there is quite some work on “architecture complexity”
(query #1), but most of this work is focused on non-IT architectures (buildings,
facilities, models), hardware architectures (system-on-chip, FPGA etc.) or general software
architectures. However, there is not much work on architecture complexity of digital
systems, intelligent systems or artificial intelligence (queries #2 to #4). Most papers
found were on system-on-chip architectures or protein structures. The only relevant
paper [
          <xref ref-type="bibr" rid="ref20">20</xref>
          ] proposes an approach for evaluating the complexity of EA components
landscapes with a focus on public administration. This approach could be relevant for our
long-term aim to provide method support, but it is not tackling our current focus of
understanding the changes in complexity caused by AI. The search for papers on
architecture complexity in the context of digital transformation (query #5) also returned only
one relevant paper [
          <xref ref-type="bibr" rid="ref21">21</xref>
          ] that investigates how to monitor complexity of IT-architectures.
However, this paper does not address the effects of AI and might be relevant only for
our future work.
4
        </p>
      </sec>
    </sec>
    <sec id="sec-4">
      <title>Industrial Case Studies</title>
      <p>The two case studies described in this section were selected from different research and
development projects with industrial partners conducted at Rostock University during
fall 2019 and spring 2020. The participating researchers made notes during meetings,
collected documents and field notes when working with the companies. This material
forms the basis for the case studies and is presented in a condensed way in this section.
4.1</p>
      <sec id="sec-4-1">
        <title>Case A: AI for Fraud Detection</title>
        <p>Case study company A is a small payment service provider from Germany offering
various IT-based services for handling payment transactions for small and
mediumsized banks. The company was among the first in Germany to offer support for instant
payment transactions (IPT). Today it normally takes one business day for a payment to
reach the beneficiary, but instant payments realize this in close to real-time (i.e., within
less than 10 seconds). This is independent of the underlying payment instrument used
(credit transfer, direct debit or payment card) and clearing (bilateral interbank clearing
or clearing via infrastructures) or settlement (e.g. with guarantees or in real time).</p>
        <p>Instant payment solutions usually consist of the scheme layer (end-user solutions for
the market), clearing layer (arrangements for clearing of transactions between payment
service providers) and settlement layer (arrangements for settlement of transactions).
Company A provides clearing layer and settlement layer functions in combination with
value-added services, such as fraud detection, sanction screening and embargo
checking. The case considered in this paper emerged when the company decided to explore
possibilities of AI use in IPT handling</p>
        <p>
          After a requirements analysis, the case study company performed a feasibility study
that investigated different AI approaches for detecting fraudulent transactions [
          <xref ref-type="bibr" rid="ref31">31</xref>
          ] and
developed a concept how to integrate the required AI sub-system into the existing
enterprise architecture. In the business architecture, the future roles expected to use the
AI solution for IP fraud detection were identified. These roles are the ones who need to
understand the decisions of the AI solution. Furthermore, the business process steps to
be automated by the future AI component also had to be determined and the related
affected tasks of other processes were located. This makes clear what process steps
deliver input and what steps need to receive output information.
        </p>
        <p>In the information architecture, focus was on identifying what information required
for the fraud detection already is available (and what applications or services in the
application architecture provide or consume this information) and, more important,
what information is missing. Here, the required information for fraud detection is
spread onto different data sources (payment monitoring system, core banking system,
customer transaction history). With this distribution onto different data sources, an
integrated data set has to be created to allow for a performant implementation of the AI
solution. Integrating data “on the fly” would require too much time and disturb the other
application using the same data.</p>
        <p>In the application and technology architecture, the applications affected by a new AI
solution, either because they have to provide data or because they receive the AI
solution’s results, were identified. Furthermore, the technology currently used indicated
constraints for the future AI solutions with respect to physical location of data storages
and technical architecture of the services used.</p>
        <p>Figure 1 shows an excerpt of the architecture model for case A with focus on
investigation of suspicious transactions.
4.2</p>
      </sec>
      <sec id="sec-4-2">
        <title>Case B: AI for Object Recognition and Marketing Support</title>
        <p>Case study Company B is content-marketing enterprise specialized in the creation
and distribution of online-videos, and in using these videos for marketing purposes.
This company aims at new business models exploiting the possibility to create
interaction with the users and new innovative media formats. In particular, free online videos
have a high reach in the advertising-relevant target group. Such videos contain several
scenes and show mostly fashion-related content applicable for content-related
advertising. For example. if a video shows a close-up of a male face wearing sunglasses,
advertisements should be placed for these glasses. Knowing what kind of object is shown
in the video therefore is crucial for the service. Traditionally, the objects in videos were
identified by manual “tagging” of the videos. This approach is labor-intensive and
difficult to scale up due to the need to hire and train the workforce. Automatic image
detection technologies can enable more efficient and cost-effective operation.</p>
        <p>The case study company started to develop an innovative technological approach by
combining a technique from the symbolic and approximate sub-disciplines of AI
research. The aim is to apply knowledge captured in an ontology to improve the process
of object recognition in videos, which is based on an artificial neural network (ANN)
and a deep-learning approach. The ontology is supposed to capture the relevant
knowledge for the application field of discovering fashion items in videos. This
knowledge includes, for example, a taxonomy of fashion items, environments suitable
for specific fashion categories (mountain, skiing, outdoor), social contexts relevant for
fashion categories (weddings, parties), and more. Furthermore, the ontology also is
used to capture combinations of fashion items relevant for defined marketing purposes,
like, for example, the fashion for a particular target group. For each concept in the
ontology, there is a corresponding classification model in the deep learning part of the
system. This part consists of the Deep Learning Management software component
providing access to the ANN Database containing available models.</p>
        <p>From an organizational perspective, both the maintenance of the ontology, the
continued training of the deep learning module, the integration of the automatic tagging
into existing processes and the development of new business services based on this
platform had to accompany the implementation of the above AI solution. From a
technical perspective, the key task was the integration with the existing marketing and
content distribution engine, which also includes customer profiles, campaign management
and advertisements.
5
5.1</p>
      </sec>
    </sec>
    <sec id="sec-5">
      <title>Case Study Analysis</title>
      <sec id="sec-5-1">
        <title>Approach for Analyzing Architecture Complexity</title>
        <p>
          Complexity has been subject of research since several decades. In information
systems research, many scholars consider research on system complexity as more
important than algorithmic or algebraic complexity. In his well-received discussion of
hierarchy, Simon defined 1962 a complex system as a system consisting of a large
number of parts that have many interactions [
          <xref ref-type="bibr" rid="ref25">25</xref>
          ]. [
          <xref ref-type="bibr" rid="ref26">26</xref>
          ] described a complex organization as
a set of interdependent parts, which together make up a whole that is interdependent
with some larger environment. [
          <xref ref-type="bibr" rid="ref27">27</xref>
          ] investigates and describes key elements of complex
adaptive systems. As EA capture the essential structures and elements of an enterprise
and thus relate to socio-economic-technical systems, we consider the aforementioned
work on organizational complexity as relevant for our field.
        </p>
        <p>For investigating changes in complexity caused by the introduction of AI in the cases
studies, an operationalization of complexity is required. For this purpose, we consider
existing operationalizations for project complexity and product complexity as in
particular interesting. Project complexity addresses aspects of interaction of stakeholder
and processes related to the business architecture and product complexity parts and
variations of a product which is related to digital systems as “products” and their
application architecture.</p>
        <p>
          A review regarding the concept of project complexity performed by Baccarini [
          <xref ref-type="bibr" rid="ref28">28</xref>
          ]
proposes to define complexity as “consisting of many varied interrelated parts”, to
distinguish between organizational and technological complexity, and to operationalize
this in terms of “differentiation and interdependence”. Differentiation refers to the
number of varied elements, e.g. tasks or components; interdependence characterizes the
interrelatedness between these elements. Regarding organizational complexity, [
          <xref ref-type="bibr" rid="ref28">28</xref>
          ]
identified among other indicators the number of organizational units involved and the
division of labor. For technological complexity, the diversity of inputs and output and the
number of specialties (e.g. subcontractors) are considered. In the area of product
complexity, work of Hobday, [
          <xref ref-type="bibr" rid="ref29">29</xref>
          ], regarding distinctive features of complex products and
systems identifies dimensions defining the nature of a product and its complexity. The
not exhaustive list of 15 critical product dimensions provided by Hobday includes
quantity of sub-systems and components, degree of customization of products and intensity
of supplier involvement. These dimensions will be used in combination with
Baccarini’s project complexity indicators when evaluating the case studies in section 4.
5.2
        </p>
      </sec>
      <sec id="sec-5-2">
        <title>Architecture Complexity in the Case Studies</title>
        <p>Using the indicators proposed by Baccarini and Hobday (see section 5.1), we analysed
the cases in section 4 regarding the changes implemented during the introduction of AI.
The result is summarized in table 2.</p>
        <p>Judging from the “increase” in most indicators presented in table 1 for both cases,
we have reason to believe that there is confirmation for an increase in complexity. As
this concerns the business and application architecture, we argue that this concerns the
overall EA complexity. A possible explanation might be that both cases were finished
not too long ago and that a consolidation of the enterprise architecture is required that
integrates and optimizes inefficient components. This requires further investigation.
Degree of
customization
Intensity of
supplier
involvement
Business Pro- Increase: fraud detection
processes affected cess with interface to IP
trans</p>
        <p>action handling
Application Architecture
Sub-systems Increase: AI sub-system, new
and components data extraction and integration
system
No change regarding the
established IT sub-systems
No change (after finishing the
AI project)</p>
        <p>Increase: new processes for the new
roles (see above) and their interface to
existing sales and operations processes
Increase: two AI sub-systems; new
services for situation detection and
contextualization
No change regarding the established
IT sub-systems
Increase: supplier of ML component
continues to render services
6</p>
      </sec>
    </sec>
    <sec id="sec-6">
      <title>Extended Digital Enterprise Architecture Reference Cube</title>
      <p>
        Enterprise Architecture Management (EAM) defines today with frameworks,
standards, tools and practical expertise a large set of different views and perspectives. We
argue that a new complexity-focused digital enterprise architecture approach should
better enable the digitalization of adaptive intelligent products and services. DEA –
Digital Enterprise Architecture Reference Cube (Fig. 2) is our current extended
architectural reference model from [
        <xref ref-type="bibr" rid="ref30">30</xref>
        ] to support architecture management, engineering,
and analytics considering a set of multi-perspective viewpoints for enterprise
architectures. Our research focused to the presented industrial case studies essentially defines
the original base of the Digital Enterprise Architecture Reference Cube (DEA), having
now eleven integral architecture domains for a holistic architecture classification
model. The integral architecture areas of the DEA have a core of standardized
architecture aspects and their relations to TOGAF and ArchiMate and extend these standardized
architecture domains with our perspectives that focus on the new topics of Artificial
Intelligence-based digitalization.
      </p>
      <p>DEA - Digital Enterprise Architecture Reference Cube provides our comprehensive
architectural reference model to integrate in a bottom-up manner dynamically
composed micro-granular architectural services and their models for supporting intelligent
digital services and products. We have extended our service-oriented enterprise
architecture reference model for the evolving digital transformation context by
micro-granular structures, like the Internet of Things, and Microservices. Further, we have
associated multi-perspective architectural decision models, which are supported by
viewpoints and functions of an architecture management cockpit.</p>
      <p>Fig. 2. Digital Enterprise Architecture Reference Cube</p>
      <p>Digital enterprise architecture should be both holistic and easily adaptable to support
micro-granular structures like IoT and the digital transformation with new business
models and technologies, like social software, big data, services computing with cloud
computing, mobility platforms and systems, security systems, and semantics support.</p>
      <p>DEA is more specific than existing architectural standards of EAM – Enterprise
Architecture Management and extends these architectural standards for digital enterprise
architectures with services and cloud computing. DEA provides a holistic classification
model with ten integral architectural domains. These architectural domains cover
specific architectural viewpoint descriptions in accordance to the orthogonal dimensions
of both architectural layers and architectural aspects. DEA abstracts from a concrete
business scenario or technologies, but it is applicable for concrete architectural
instantiations to support digital transformations.</p>
      <p>Metamodels and their architectural data are the core part of the digitization
architecture. Architecture metamodels should support analytics-based architectural decision
management and the strategic as well as IT/business alignment. Three quality
perspectives are important for an adequate IT/business alignment and are differentiated as: (I)
IT system qualities: performance, interoperability, availability, usability, accuracy,
maintainability, and suitability; (II) business qualities: flexibility, efficiency,
effectiveness, integration and coordination, decision support, control and follow up, and
organizational culture; and finally (III) governance qualities: plan and organize, acquire and
implement deliver and support, monitor and evaluate.</p>
      <p>DEA abstracts from a particular business scenario or technology because it can be
applied to concrete architecture instantiations to support digital transformations
independently of different domains. The DEA reference cube covers the top of the Platform
and Ecosystem Architecture. A digital platform is in our understanding a repository of
business, data, and infrastructure services used to configure digital offerings from
digital services rapidly. Digital Services and components are slices of code that perform a
specific task. We position reusable digital services as parts of an ecosystem of services.
A digital platform linearizes the complexity of cooperating services. It integrates core
technology services to provide standardized access points and repositories for an
intelligent service ecosystem of business services, data services, and infrastructure services.
The value of a platform to users results from the number of platform and service users.
A digital platform and an ecosystem should enable shared value creation for all
stakeholders and facilitate the exchange of goods, services, and social currency. Platforms
do not own or control their resources and are therefore well suited for scalability within
the ecosystem.
7</p>
    </sec>
    <sec id="sec-7">
      <title>Concluding Remarks and Future Work</title>
      <p>Based on established definitions of complexity, in particular from project and
product management, the paper investigated possible changes in complexity when AI
functionality was added to business services and enterprise architecture. The investigated
cases confirm our conjecture that the EA grows more complex. However, due to the
very small number of cases, more work is needed in this area. So far, we consider our
results only as a confirmation of the problem relevance.</p>
      <p>One of the building blocks for methodical support to managing complexity is – to
our opinion – the use of EAM and the differentiation into different perspectives as
presented in section 6 when discussing the extended version of the Enterprise Architecture
Reference Cube.</p>
      <p>Future work will have to include the investigation of more cases to more clearly
define requirements to the methodical support. Furthermore, the overall DSR process
described in section 2 has to be continued by clarifying root causes and designing an
initial method proposal.</p>
    </sec>
  </body>
  <back>
    <ref-list>
      <ref id="ref1">
        <mixed-citation>
          1.
          <string-name>
            <surname>Ross</surname>
            ,
            <given-names>J.W.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Beath</surname>
            ,
            <given-names>C.M.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Mocker</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          :
          <article-title>Designed for Digital. How to Architect Your Business for Sustained Success</article-title>
          . The MIT Press (
          <year>2019</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref2">
        <mixed-citation>
          2.
          <string-name>
            <surname>McAfee</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Brynjolfsson</surname>
          </string-name>
          , E.: Machine, Platform, Crowd. Harnessing Our Digital Future. W. W. Norton &amp; Company (
          <year>2017</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref3">
        <mixed-citation>
          3.
          <string-name>
            <surname>Rogers</surname>
            ,
            <given-names>D. L.</given-names>
          </string-name>
          :
          <article-title>The Digital Transformation Playbook</article-title>
          . Columbia University Press (
          <year>2016</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref4">
        <mixed-citation>
          4.
          <string-name>
            <surname>Russel</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Norvig</surname>
            ,
            <given-names>P.: Artificial</given-names>
          </string-name>
          <string-name>
            <surname>Intelligence</surname>
            .
            <given-names>A Modern</given-names>
          </string-name>
          <string-name>
            <surname>Approach. Pearson</surname>
          </string-name>
          (
          <year>2015</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref5">
        <mixed-citation>
          5.
          <string-name>
            <surname>Poole</surname>
            ,
            <given-names>D.L.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Mackworth</surname>
            ,
            <given-names>A.K.</given-names>
          </string-name>
          :
          <source>Artificial Intelligence. Foundations of Computational Agents</source>
          . Cambridge University Press (
          <year>2018</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref6">
        <mixed-citation>
          6.
          <string-name>
            <surname>Sandkuhl</surname>
            ,
            <given-names>K.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Seigerroth</surname>
            ,
            <given-names>U.</given-names>
          </string-name>
          , &amp;
          <string-name>
            <surname>Kaidalova</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          :
          <article-title>Towards Integration Methods of Product-IT into Enterprise Architectures</article-title>
          .
          <source>In 2017 IEEE EDOCW</source>
          ,
          <volume>23</volume>
          -
          <fpage>28</fpage>
          (
          <year>2017</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref7">
        <mixed-citation>
          7.
          <string-name>
            <surname>Ahlemann</surname>
            ,
            <given-names>F.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Stettiner</surname>
            ,
            <given-names>E.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Messerschmidt</surname>
            , M. and
            <given-names>C.</given-names>
          </string-name>
          <string-name>
            <surname>Legner</surname>
          </string-name>
          (
          <year>2012</year>
          )
          <article-title>Strategic enterprise architecture management: challenges, best practices</article-title>
          , and future developments: Springer Science &amp; Business
          <string-name>
            <surname>Media</surname>
          </string-name>
          ,
          <year>2012</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref8">
        <mixed-citation>
          8.
          <string-name>
            <surname>Wißotzki</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          and
          <string-name>
            <given-names>K.</given-names>
            <surname>Sandkuhl</surname>
          </string-name>
          (
          <year>2015</year>
          )
          <article-title>Elements and characteristics of enterprise architecture capabilities</article-title>
          .
          <source>in International Conference on Business Informatics Research</source>
          ,
          <year>2015</year>
          , pp.
          <fpage>82</fpage>
          -
          <lpage>96</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref9">
        <mixed-citation>
          9.
          <string-name>
            <surname>Buckl</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Dierl</surname>
            ,
            <given-names>T.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Matthes</surname>
          </string-name>
          , F. and
          <string-name>
            <surname>C. M. Schweda</surname>
          </string-name>
          (
          <year>2010</year>
          )
          <article-title>Building blocks for enterprise architecture management solutions</article-title>
          .
          <source>in Working Conference on Practice-Driven Research on Enterprise Transformation</source>
          ,
          <year>2010</year>
          , pp.
          <fpage>17</fpage>
          -
          <lpage>46</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref10">
        <mixed-citation>
          10.
          <string-name>
            <surname>Glissmann</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          and J.
          <string-name>
            <surname>Sanz</surname>
          </string-name>
          (
          <year>2011</year>
          )
          <article-title>An approach to building effective enterprise architectures,"</article-title>
          <source>in System Sciences (HICSS)</source>
          ,
          <year>2011</year>
          44th Hawaii International Conference on,
          <year>2011</year>
          , pp.
          <fpage>1</fpage>
          -
          <lpage>10</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref11">
        <mixed-citation>
          11.
          <string-name>
            <surname>Sandkuhl</surname>
            ,
            <given-names>K.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Simon</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Wißotzki</surname>
            , M. and
            <given-names>C.</given-names>
          </string-name>
          <string-name>
            <surname>Starke</surname>
          </string-name>
          (
          <year>2015</year>
          )
          <article-title>The Nature and a Process for Development of Enterprise Architecture Principles,"</article-title>
          <source>in International Conference on Business Information Systems</source>
          ,
          <year>2015</year>
          , pp.
          <fpage>260</fpage>
          -
          <lpage>272</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref12">
        <mixed-citation>
          12.
          <string-name>
            <surname>Johnson</surname>
            ,
            <given-names>P.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Lagerström</surname>
            ,
            <given-names>R.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Närman</surname>
            ,
            <given-names>P.</given-names>
          </string-name>
          and
          <string-name>
            <surname>M. Simonsson</surname>
          </string-name>
          (
          <year>2007</year>
          )
          <article-title>Enterprise architecture analysis with extended influence diagrams,"</article-title>
          <source>Information Systems Frontiers</source>
          , vol.
          <volume>9</volume>
          , pp.
          <fpage>163</fpage>
          -
          <lpage>180</lpage>
          ,
          <year>2007</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref13">
        <mixed-citation>
          13.
          <string-name>
            <surname>Johnson</surname>
            ,
            <given-names>P.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Ekstedt</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Silva</surname>
            ,
            <given-names>E.</given-names>
          </string-name>
          and L.
          <string-name>
            <surname>Plazaola</surname>
          </string-name>
          (
          <year>2004</year>
          )
          <article-title>Using enterprise architecture for cio decision-making: On the importance of theory,"</article-title>
          <source>in Second Annual Conference on Systems Engineering Research</source>
          ,
          <year>2004</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref14">
        <mixed-citation>
          14.
          <string-name>
            <surname>Zimmermann</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Schmidt</surname>
            ,
            <given-names>R.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Sandkuhl</surname>
            ,
            <given-names>K.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Jugel</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Bogner</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Möhring</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          :
          <article-title>Decisionoriented Coposition Architecture for Digital Transformation</article-title>
          . In Czarnowski, I.,
          <string-name>
            <surname>Howlett</surname>
            ,
            <given-names>R.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Jain</surname>
            ,
            <given-names>L. C.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Vlacic</surname>
            ,
            <given-names>L</given-names>
          </string-name>
          . (Eds.):
          <source>Intelligent Decision Technologies</source>
          <year>2018</year>
          ,
          <fpage>109</fpage>
          -
          <lpage>119</lpage>
          (
          <year>2018</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref15">
        <mixed-citation>
          15.
          <string-name>
            <surname>Masuda</surname>
            ,
            <given-names>Y.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Viswanathan</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          :
          <article-title>Enterprise Architecture for Global Companies in a Digital IT Era</article-title>
          . Springer (
          <year>2019</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref16">
        <mixed-citation>
          16.
          <string-name>
            <surname>Hwang</surname>
            ,
            <given-names>K.</given-names>
          </string-name>
          :
          <article-title>Cloud Computing for Machine Learning</article-title>
          and
          <string-name>
            <given-names>Cognitive</given-names>
            <surname>Applications</surname>
          </string-name>
          . The MIT Press (
          <year>2017</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref17">
        <mixed-citation>
          17.
          <string-name>
            <surname>Skansi</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          : Introduction to Deep Learning. Springer (
          <year>2018</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref18">
        <mixed-citation>
          18.
          <string-name>
            <surname>Munakata</surname>
            ,
            <given-names>T.</given-names>
          </string-name>
          :
          <source>Fundamentals of the New Artificial Intelligence. Neural, Evolutionary, Fuzzy and More</source>
          . Springer (
          <year>2008</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref19">
        <mixed-citation>
          19.
          <string-name>
            <surname>Warren</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          :
          <article-title>Amazon Echo: The Ultimate Amazon Echo User Guide 2016 Become an Alexa and Echo Expert Now! USA: CreateSpace Independent Publishing (</article-title>
          <year>2016</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref20">
        <mixed-citation>
          20.
          <string-name>
            <surname>Lakhrouit</surname>
            J. and
            <given-names>K.</given-names>
          </string-name>
          <string-name>
            <surname>Baïna</surname>
          </string-name>
          (
          <year>2015</year>
          )
          <article-title>Evaluating complexity of enterprise architecture components landscapes,"</article-title>
          <source>2015 10th International Conference on Intelligent Systems: Theories and Applications</source>
          (SITA),
          <year>Rabat</year>
          ,
          <year>2015</year>
          , pp.
          <fpage>1</fpage>
          -
          <lpage>5</lpage>
          , doi: 10.1109/SITA.
          <year>2015</year>
          .7358443
        </mixed-citation>
      </ref>
      <ref id="ref21">
        <mixed-citation>
          21.
          <string-name>
            <surname>Widjaja</surname>
          </string-name>
          , Thomas and Gregory, Robert
          <string-name>
            <surname>Wayne</surname>
          </string-name>
          (
          <year>2020</year>
          )
          <article-title>"Monitoring the Complexity of IT Architectures: Design Principles and an IT Artifact,"</article-title>
          <source>Journal of the Association for Information Systems:</source>
          Vol.
          <volume>21</volume>
          : Iss.
          <article-title>3 , Article 4</article-title>
          . DOI:
          <volume>10</volume>
          .17705/1jais.00616
        </mixed-citation>
      </ref>
      <ref id="ref22">
        <mixed-citation>
          22.
          <string-name>
            <surname>Kitchenham</surname>
            ,
            <given-names>B.A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Charters</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          :
          <article-title>Guidelines for performing Systematic Literature Reviews in Software Engineering</article-title>
          . In: Software Engineering Group, School of Computer Science and Mathematics, Keele University, pp.
          <fpage>1</fpage>
          -
          <lpage>57</lpage>
          . (
          <year>2007</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref23">
        <mixed-citation>
          23.
          <string-name>
            <surname>Johannesson</surname>
            <given-names>P.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Perjons</surname>
            <given-names>E.</given-names>
          </string-name>
          (
          <year>2014</year>
          )
          <article-title>An Introduction to Design Science</article-title>
          . Springer.
        </mixed-citation>
      </ref>
      <ref id="ref24">
        <mixed-citation>
          24.
          <string-name>
            <surname>Yin</surname>
            ,
            <given-names>R.K.</given-names>
          </string-name>
          :
          <article-title>Case study research. Design and methods</article-title>
          .
          <source>SAGE Publications</source>
          , Inc, Thousand
          <string-name>
            <surname>Oaks</surname>
          </string-name>
          (
          <year>2013</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref25">
        <mixed-citation>
          25.
          <string-name>
            <surname>Simon</surname>
            ,
            <given-names>Herbert A.</given-names>
          </string-name>
          <year>1996</year>
          .
          <source>The Sciences of the Artificial</source>
          , 3rd ed. MIT Press, Cambridge, MA
        </mixed-citation>
      </ref>
      <ref id="ref26">
        <mixed-citation>
          26.
          <string-name>
            <surname>Thompson</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          <year>1967</year>
          . Organizations in Action.
          <source>McGraw-Hill</source>
          , New York.
        </mixed-citation>
      </ref>
      <ref id="ref27">
        <mixed-citation>
          27.
          <string-name>
            <surname>Philip</surname>
          </string-name>
          <article-title>Anderson: Perspective: Complexity Theory and Organization Science</article-title>
          . Organization Science,
          <year>June 1999</year>
          . INFORMS.
        </mixed-citation>
      </ref>
      <ref id="ref28">
        <mixed-citation>
          28.
          <string-name>
            <surname>Baccarini</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          (
          <year>1996</year>
          ).
          <article-title>The concept of project complexity - a review</article-title>
          .
          <source>International Journal of Project Management</source>
          ,
          <volume>14</volume>
          :
          <fpage>201</fpage>
          -
          <lpage>204</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref29">
        <mixed-citation>
          29.
          <string-name>
            <surname>Hobday</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          (
          <year>1998</year>
          ).
          <source>Product Complexity, Innovation and Industrial Organisation. Research Policy</source>
          ,
          <volume>26</volume>
          :
          <fpage>689</fpage>
          -
          <lpage>710</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref30">
        <mixed-citation>
          30.
          <string-name>
            <surname>Zimmermann</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Schmidt</surname>
            ,
            <given-names>R.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Sandkuhl</surname>
            ,
            <given-names>K.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Jugel</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Schweda</surname>
            ,
            <given-names>C.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Bogner</surname>
            ,
            <given-names>J</given-names>
          </string-name>
          (
          <year>2020</year>
          )
          <article-title>Architecting Digital Products</article-title>
          and
          <article-title>Services</article-title>
          . In
          <string-name>
            <surname>Zimmermann</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Schmidt</surname>
            ,
            <given-names>R.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Jain</surname>
          </string-name>
          . L. C.
          <article-title>: Architecting the Digital Transformation</article-title>
          .
          <source>Springer</source>
          <year>2020</year>
          ,
          <volume>181</volume>
          -
          <fpage>197</fpage>
        </mixed-citation>
      </ref>
      <ref id="ref31">
        <mixed-citation>
          31.
          <string-name>
            <surname>Diadiushkin</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Sandkuhl</surname>
            ,
            <given-names>K.</given-names>
          </string-name>
          , &amp;
          <string-name>
            <surname>Maiatin</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          (
          <year>2019</year>
          ).
          <article-title>Fraud Detection in Payments Transactions: Overview of Existing Approaches and Usage for Instant Payments</article-title>
          .
          <source>Complex Systems Informatics and Modeling Quarterly</source>
          , (
          <volume>20</volume>
          ),
          <fpage>72</fpage>
          -
          <lpage>88</lpage>
          .
        </mixed-citation>
      </ref>
    </ref-list>
  </back>
</article>