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  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Comparing the Gained Benefits from Product Configuration Systems Based on Maintenance Efforts</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Sara Shafiee</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Lars Hvam</string-name>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Anders Haug</string-name>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Mechanical Engineering Department, Technical University of</institution>
          <country country="DK">Denmark</country>
        </aff>
      </contrib-group>
      <abstract>
        <p>1 Product Configuration Systems (PCSs) are automatic solutions to support and facilitate sales and engineering processes. PCSs are among the most successful applications of expert system technology and one of the drivers in the digitalization era. Therefore, there are several studies on the benefits of PCS. Such studies are, however, often relatively undetailed or unspecific about the costs and benefits of such projects. To address this issue, this paper presents studies of four PCS projects, which quantify benefits in terms of reduced working hours, and the costs in terms of development, implementation, and maintenance costs. The studies of the PCS projects each concern a 3-year utilization period. Our results show that the gained benefits from PCS has a growing trend over the years in case of proper maintenance. We also demonstrate the opposite is the case if not properly maintaining the PCSs. Furthermore, the study reveals that PCSs with the constant maintenance grow increasingly popular (i.e., use frequency) over time, while PCSs with poor maintenance decrease in popularity.</p>
      </abstract>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>INTRODUCTION</title>
      <p>
        Customers have become accustomed to having products
customized to their personal needs while retaining the price
associated with mass production [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ]. Here, Product Configuration
Systems (PCSs) can facilitate sales and production processes for
customized products at prices comparable to mass produced [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ].
PCSs affect the company’s ability to increase the accuracy of the
cost calculations in the sales phase, consequently increasing the
efficiency of sales and engineering process [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ]. PCSs are
developed through describing information about product features,
product structure, production processes, costs and prices in their
knowledge bases [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ]. PCSs support decision-making processes in
the product engineering and sales phases by determining important
decisions regarding product features and offering users information
about product designs and costs [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ], [
        <xref ref-type="bibr" rid="ref5">5</xref>
        ].
      </p>
      <p>
        PCSs can bring substantial benefits to companies such as,
shorter lead time for generating quotations, fewer errors, increased
ability to meet customers’ requirements regarding product
functionality, use of fewer resources, optimized product designs,
less routine work and improved on-time delivery [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ], [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ]–[
        <xref ref-type="bibr" rid="ref8">8</xref>
        ].
Although advantages of PCSs are evident, there are still some
difficulties associated with required high investment [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ], [
        <xref ref-type="bibr" rid="ref9">9</xref>
        ] and
the high chances of failure [
        <xref ref-type="bibr" rid="ref10">10</xref>
        ]. Hence, researchers have provided
empirical data from case studies to better understand the
advantages, challenges, failure causes, expectations and risks
associated with PCS projects [
        <xref ref-type="bibr" rid="ref5">5</xref>
        ], [
        <xref ref-type="bibr" rid="ref10">10</xref>
        ]. Such studies are, however,
often relatively undetailed or unspecific about the costs and
benefits of such projects. Thus, although the literature provides a
variety of methods to support the development and implementation
of product configurators, it remains unclear how to estimate the
costs and benefits for different scenarios [
        <xref ref-type="bibr" rid="ref9">9</xref>
        ]–[
        <xref ref-type="bibr" rid="ref11">11</xref>
        ].
      </p>
      <p>
        To harvest the benefits of a PCS, great efforts and investments
must be undertaken [
        <xref ref-type="bibr" rid="ref5">5</xref>
        ]. In this context, some research point to a
lack of PCS maintenance as the main reason for project failure
[
        <xref ref-type="bibr" rid="ref10">10</xref>
        ], [
        <xref ref-type="bibr" rid="ref12">12</xref>
        ]. The maintenance process in PCS involves constantly
updating the PCS knowledge base and being responsive to
including alternative requirements [
        <xref ref-type="bibr" rid="ref12">12</xref>
        ].
      </p>
      <p>
        The research presented in this paper uses a case company to
investigate the financial consequences of not maintaining a PCS
properly by comparing four of its projects. The aim is to evaluate
the trend of the gained benefits from PCS during the years after
development. Here, it is the assumption that PCS projects benefits
from proper and constant maintenance and updating in the years
after implementation [
        <xref ref-type="bibr" rid="ref12">12</xref>
        ]. This study also sets out to generalize
based on these findings concerning how the profitability of the
PCS projects in the years after development can be forecasted.
With the aim to investigate these effects, the following
propositions are developed:
      </p>
      <p>Proposition 1. A PCS project will increase popularity and
produce greater benefits in the years after development in case of
continuous maintenance and updating.</p>
      <p>Proposition 2. A PCS project will lose popularity and benefits
in the years after development in case of not employing continuous
maintenance and updating.</p>
      <p>To achieve this, we calculate the costs and benefits of four
different projects during their last 3-years. In this context, we focus
on the saved man-hours in the calculation of benefits in the four
PCS projects. Then, we compare the yearly benefits from each
project to illustrate any trend of change during the 3-years. Finally,
based on the knowledge in the literature and our research
propositions, we demonstrate the results using graphs and discuss
the findings.
2</p>
    </sec>
    <sec id="sec-2">
      <title>RELATED WORKS</title>
      <p>The relevant literature was reviewed to clarify the present study’s
position in relation to existing research. This allowed us not only to
ascertain whether this research has the potential to add to the
existing knowledge but also to identify which parts of the available
knowledge are relevant to define the study’s scope. In this section,
the relevant literature on calculating the PCS cost- benefits and
PCS complexity is reviewed and subsequently utilized for
Copyright © 2019 for this paper by its authors. Use permitted uﻮndﻫerﺎCﻳreative Commons License Attribution 4.0 International (CC BY 4.0).
calculating the ROI (return on investment) and PCS complexity in
four cases of this study. The importance of constant maintenance of
PCS projects and its influence on PCS projects’ profitability is also
investigated. Finally, PCS complexity and complexity
measurements are discussed.
2.1</p>
    </sec>
    <sec id="sec-3">
      <title>Cost benefit analysis for PCS</title>
      <p>
        Several studies have addressed the cost factors of PCSs. Forza and
Salvador [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ] mentioned that a large investment in terms of
manhours may be needed to implement a PCS. Hvam [
        <xref ref-type="bibr" rid="ref13">13</xref>
        ] reported that
in one case, the cost of developing and implementing a PCS in a
large ETO companies was approximately USD 1 million, with
operating costs of USD 100,000 per year. These costs are
compared to the usage of the system, which is estimated in order to
generate a budget and detailed quotations, according to which the
total sales price is USD 200 million [
        <xref ref-type="bibr" rid="ref11">11</xref>
        ]. Haug et al. [
        <xref ref-type="bibr" rid="ref14">14</xref>
        ] elaborate
on how man-hours in the configuration process can be reduced by
up to 78.4%. Moreover, Hvam et al.’s [
        <xref ref-type="bibr" rid="ref15">15</xref>
        ] study indicates that
after utilization of PCS at the case company, the lead time required
to generate an offer was reduced by 94–99%. The reduction can be
traced to automation of routine tasks and elimination of the
iterative loops between domain experts, as PCS makes all product
knowledge available [
        <xref ref-type="bibr" rid="ref16">16</xref>
        ]. Three main types of benefits are
mentioned in the literature [
        <xref ref-type="bibr" rid="ref9">9</xref>
        ]: (1) time reduction (man-hours and
lead time), (2) product specification quality improvement and (3)
sales increase.
      </p>
      <p>
        Costs of configurators has also been discussed [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ], [
        <xref ref-type="bibr" rid="ref13">13</xref>
        ] and they
include software licenses (the cost of buying the software and
annual licenses) as well as internal and external man-hours for
modelling, programming, and implementing the configurator. The
costs consist partly of the initial costs of making the configurator
and partly of the annual costs of maintaining and operating it [
        <xref ref-type="bibr" rid="ref17">17</xref>
        ].
However, there are still some hidden costs, such as the time needed
for people to learn and use the system – costs that, however, can be
measured as man-hours [
        <xref ref-type="bibr" rid="ref18">18</xref>
        ].
2.2
      </p>
    </sec>
    <sec id="sec-4">
      <title>Documentation and maintenance of PCSs</title>
      <p>
        One of the main challenges when using PCSs concerns a lack of
documentation, which can lead to incomplete and outdated systems
that are difficult to understand [
        <xref ref-type="bibr" rid="ref19">19</xref>
        ], [
        <xref ref-type="bibr" rid="ref20">20</xref>
        ]. For a company using a
PCS, it is therefore crucial to have an efficient system for
documenting the structure, attributes, and constraints modelled
within the system, as well as to facilitate communication between
PCS developers and domain experts [
        <xref ref-type="bibr" rid="ref12">12</xref>
        ]. Documentation is a vital
part of all IT projects, as it is used for sharing knowledge between
people and reducing knowledge loss, when team members become
inaccessible [
        <xref ref-type="bibr" rid="ref10">10</xref>
        ], [
        <xref ref-type="bibr" rid="ref21">21</xref>
        ], [
        <xref ref-type="bibr" rid="ref22">22</xref>
        ]. The documentation of PCS includes
modelling, maintaining and updating the product model, and
storing all information related to the products’ attributes,
constraints and rules in the PCS [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ].
      </p>
      <p>
        Studies of companies using configurators have revealed that,
without a planned systematic approach, companies are unable to
develop and maintain their configurators [
        <xref ref-type="bibr" rid="ref20">20</xref>
        ]. Modelling
techniques are used as documentation tools alongside the task of
communication and validation of product information [
        <xref ref-type="bibr" rid="ref16">16</xref>
        ], [
        <xref ref-type="bibr" rid="ref23">23</xref>
        ].
Research supports the modelling process by adding software
support and integrating these different modelling techniques (PVM
(product variant master) and CRC
(class-responsibilitycollaboration) cards) [
        <xref ref-type="bibr" rid="ref8">8</xref>
        ], [
        <xref ref-type="bibr" rid="ref24">24</xref>
        ]. Other studies report that one the
main reason for the PCS projects failure is the lack of the proper
documentation and maintenance [
        <xref ref-type="bibr" rid="ref10">10</xref>
        ]. In other words, not
performing maintenance and updating tasks can have significant
negative consequences [
        <xref ref-type="bibr" rid="ref25">25</xref>
        ], [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ], [
        <xref ref-type="bibr" rid="ref26">26</xref>
        ], [
        <xref ref-type="bibr" rid="ref27">27</xref>
        ].
      </p>
      <p>
        The economic implications of the maintenance of data
repositories can be examined in terms of costs and benefits [
        <xref ref-type="bibr" rid="ref28">28</xref>
        ].
The results of such analyses indicate that although the cost of
maintaining a PCS can be relatively high, it cannot be ignored as it
risks wasting the investment. Hence, economic and business
benefits can justify the maintenance costs, as continuous updates of
the PCS are needed to ensure the accuracy and timeliness of the
configuration data.
Complexity is one the most discussed challenges in software
development and maintenance [
        <xref ref-type="bibr" rid="ref16">16</xref>
        ], [
        <xref ref-type="bibr" rid="ref29">29</xref>
        ]. In PCS projects, the
complexity of PCS is associated directly with the complexity of
targeted products. As PCS complexity increases, the task of
maintaining the PCS becomes more challenging and costly [
        <xref ref-type="bibr" rid="ref30">30</xref>
        ].
      </p>
      <p>
        To measure the complexity of PCSs, Brown et al. [
        <xref ref-type="bibr" rid="ref31">31</xref>
        ] defines
three major complexity dimensions; 1) execution complexity, 2)
parameter complexity, and 3) memory complexity. Execution
complexity covers the complexity involved in performing the
configuration actions that make up the configuration procedure,
while the memory complexity refers to the number of parameters
that system manager must remember. In this paper, we measure the
complexity involved in the knowledge that domain expert provides
during the creation of the configuration model [
        <xref ref-type="bibr" rid="ref31">31</xref>
        ], which could
also be an indicator of the product complexity leading to the PCS
complexity. Therefore, we assess the parameter complexity in
terms of two major PCS knowledge base characteristics: attributes
and constraints (Table 1).
      </p>
      <sec id="sec-4-1">
        <title>Low complexity</title>
      </sec>
      <sec id="sec-4-2">
        <title>Medium complexity</title>
      </sec>
      <sec id="sec-4-3">
        <title>High complexity</title>
        <p>In this paper, we measure the complexity of each PCS projects as
sum of attributes and constraints. The complexity is highlighted as
one of the main the background information on PCS projects as the
higher complexity dictates the higher effort in development and
maintenance tasks for PCS projects.
3</p>
      </sec>
    </sec>
    <sec id="sec-5">
      <title>RESEARCH METHODOLOGY</title>
      <p>Different research has employed cost-benefit analysis for PCSs
using different cost factors such as the saved man-hours, increased
sales, improved quality and reduction in errors and defects. To
date, there is little research that investigates the trends of
costbenefits in PCS projects over time to estimate the changes in
profitability considering different variants. The number of research
papers providing detailed data from real case projects are also
limited. Thus, a explorative approach was employed in the form of
a case study approach.</p>
      <p>The company selected for case studies produces highly
engineered products and technology. More specifically, studies of
four configurator projects were carried out at a large Danish ETO
company, which produces chemical processing systems. The case
company was chosen because it:
offers highly engineered and complex products;
had recently implemented PCS projects – including
projects with frequent and more sporadic maintenance
efforts;
had measured/estimated costs and benefits of PCS
projects over the last three years; and
offered a unique level of access to project data.</p>
      <p>The reason for choosing one case company for the four studies of
PCS projects was to provide the in-depth data analysis and be able
to observe the changes in benefits over time, while keeping many
external factors (such as organizational culture, IT department and
PCS software shell) as fixed as possible.</p>
      <p>ETO companies normally engineer the products with high
complexity based on customer request. Hence, we chose the case
projects with the most complex products. The initial criteria for
choosing the four projects were:







maximum similarities between the four PCS project
contexts to keep external factors constant;
differences in costs and benefits;
 similar users (engineers);
different PCS use frequency (number of generated
quotes);
 two projects with continuous maintenance and two with
limited maintenance during the last three years;
 same IT team and the involvement of similar tasks during
development and maintenance;
 similar software platform and integrations.</p>
      <p>All the PCS projects focused on sales process automation in
situations where generated quotations were not significantly
affected by market fluctuations, depended on the requests from the
customer. Here, the company experts generate the quotes from the
sale PCS in order to offer the price and all the specifications to the
customer based on his/her requirements. Cases 1 and 2 received
continues proper maintenance during the last three year; while
cases 3 and 4 has been rarely updated. Table 2 shows information
related to the four selected PCS projects. The complexity ratio on
different projects indicates the task of maintaining the PCS as the
higher complex projects require more challenging and costly
maintenance tasks.</p>
      <sec id="sec-5-1">
        <title>Case Studies</title>
      </sec>
      <sec id="sec-5-2">
        <title>Case 1</title>
      </sec>
      <sec id="sec-5-3">
        <title>Case 2</title>
      </sec>
      <sec id="sec-5-4">
        <title>Case 3</title>
      </sec>
      <sec id="sec-5-5">
        <title>Case 4</title>
        <p>choosing man-hours is the ease of access to these data, as well as
the uncertainty related to other factors – as, for example, increased
sales and improved product quality, which could be results of other
factors than the PCS. The number of saved man-hours before and
after using the configurator and the gained benefits based on the
saved man-hours are calculated for the last 3-years. The total costs
of each project is calculated based on the development,
implementation and the yearly running costs (such as licenses and
maintenance activities) for the last 3-years.</p>
        <p>
          Analyzing the costs and benefits from the last 3 years at the
case company allows us to benefit from the use comparative
multiple case study method [
          <xref ref-type="bibr" rid="ref32">32</xref>
          ], [
          <xref ref-type="bibr" rid="ref33">33</xref>
          ]. Case-based research seeks
to find logical connections among observed events, relying on
knowledge of how systems, organizations, and individuals work
[
          <xref ref-type="bibr" rid="ref33">33</xref>
          ], [
          <xref ref-type="bibr" rid="ref34">34</xref>
          ]. Furthermore, case studies provide researchers with a
deeper understanding of the relations among the variables and
phenomena that are not fully examined or understood [
          <xref ref-type="bibr" rid="ref35">35</xref>
          ], for
instance, the impact of the proper maintenance of the PCS projects
on the gained and constant benefits increase during the years.
4
        </p>
      </sec>
    </sec>
    <sec id="sec-6">
      <title>CASE STUDIES</title>
      <p>Table 3 illustrates all the figures related to the gained benefits
based on saved man-hours for each project during the first year
including development. All the costs are in Danish Kroner.
The calculation of the total benefits in Table 4 illustrates all the
figures related to the gained benefits based on saved man-hours for
each project during the second year. For the second year, we only
calculated the maintenance costs and license costs (only for users),
as there was not any development, but only maintenance.</p>
      <sec id="sec-6-1">
        <title>Case 1</title>
      </sec>
      <sec id="sec-6-2">
        <title>Case 2</title>
      </sec>
      <sec id="sec-6-3">
        <title>Case 3</title>
      </sec>
      <sec id="sec-6-4">
        <title>Case 4</title>
      </sec>
      <sec id="sec-6-5">
        <title>Case 1</title>
      </sec>
      <sec id="sec-6-6">
        <title>Case 2</title>
      </sec>
      <sec id="sec-6-7">
        <title>Case 3</title>
        <p>Case 4
s
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        <p>n
um c
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240
295
200
270
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e
to r
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fo ey ou rgu
erb erp trh ifo</p>
        <p>n
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380
310
80
150
iten -an
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ifep (ssa ohu
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e r
enB ohu
and licenses costs (only for users), as there was not any
development, but only maintenance for case 1 and 2, while not for
case 3 and 4.</p>
        <p>The numbers in Table 3-5 show a positive trend towards higher
number of generated quotations and higher benefits for the case
PCS projects with continues maintenance effort. It also
demonstrates the negative trend in both cost and benefits for the
PCS project with no maintenance efforts. The results demonstrate
that the rate of using the PCSs increases over time if the system is
maintained and updated.
The case studies demonstrate a positive trend in popularity and use
of the PCS with continuous updates, which leads to the increase in
PCS profitability.</p>
        <p>Analyzing the cost benefits across three years for case 1 and 2
clarifies that if the PCS is maintained and updated continuously,
they will be used more over the time and turn to become an
important tool among the experts. In other words, experts would
give up using other tools (such as excel sheets) and all use the
configuration system. As the number of the quotations generated
increase, the more man-hours will be saved due to the automation
and the benefits of using the PCS increase. Figure 1 demonstrates
the yearly benefits for each of the case studies. Apart from the
complexity or size of the PCS and number of saved hours, case 1
and 2 presented PCS projects with the tendency to increases in
benefits during the years. However, as illustrated in Figure 1 cases
3 and 4 have a huge decrease in use and benefits during the last
three years due to the lack of maintenance.</p>
        <p>Moreover, as the benefits of the projects increase, there is a
trend of decrease in the total costs of the projects per year. As
illustrated in Figure 2, for cases 1 and 2, the cost in year 1 includes
development cost based on the man-hours spent on development,
while in years 2 and 3, there will be just minor updates and
maintenance. For Cases 3 and 4, the maintenance efforts are just
the costs paid for licenses, after which they decrease significantly.
It can be understood from the numbers and graphs that the cost of
maintenance are very low as compared to the investments for the
initial development of a PCS. However, the maintenance efforts
and costs can have a dramatic influence on the popularity and
benefits of PCS projects.
6</p>
      </sec>
    </sec>
    <sec id="sec-7">
      <title>CONCLUSION</title>
      <p>The aim of this study was to understand the influence of the
maintenance of the PCSs on gained benefits in terms of saved
manhours. Empirical data was gathered from an ETO company based
on the previous 3-year results, which confirmed the propositions
made. Specifically, numbers for the cost and benefits for the last 3
years was available from the case company, and the complexity
was estimated based on the number of attributes and the number of
constraints in PCS. The analysis of these data led to the conclusion
that there is a positive correlation between continuous maintenance
in PCS projects and the level of gained benefits in the selected case
projects. If not engaging in maintenance efforts, in the case
projects the money is wasted on licenses and other fixed costs for
PCSs. As the studied projects showed, projects that receive no
maintenance can result in financial loss – since users do not use
PCS that are not up-to-date because of the lack of maintenance
efforts.</p>
      <p>This research is a first step in exploring the impact of
maintenance on the saved man-hours in PCS project. However,
there are generalization limitation for the paper due to the limited
number of cases and data. For future research, the study of this
paper identified a number of factors, which can influence PCS
projects’ costs and benefits, needing to be further studied. These
factors include employee experiences, user expertise, level of
details included in PCSs, and organizational culture.</p>
      <p>In this study, we compared four projects using only one
variable, namely ‘saved man-hours’. Thus, there is a need for
further research to analyze different factors, which may contribute
to the benefits of PCS projects. Future research needs to cover both
the variety of companies except the ETOs as well as a wide range
of case studies. For practice, the results of the paper may motivate
companies to give maintenance efforts a higher priority, as
opposed to solely focusing on the development and implementation
tasks.</p>
    </sec>
  </body>
  <back>
    <ref-list>
      <ref id="ref1">
        <mixed-citation>
          [1]
          <string-name>
            <given-names>A.</given-names>
            <surname>Trentin</surname>
          </string-name>
          , E. Perin, and
          <string-name>
            <given-names>C.</given-names>
            <surname>Forza</surname>
          </string-name>
          , “
          <article-title>Increasing the consumerperceived benefits of a mass-customization experience through salesconfigurator capabilities,” Computers in Industry</article-title>
          , vol.
          <volume>65</volume>
          , no.
          <issue>4</issue>
          , pp.
          <fpage>693</fpage>
          -
          <lpage>705</lpage>
          , May
          <year>2014</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref2">
        <mixed-citation>
          [2]
          <string-name>
            <given-names>A.</given-names>
            <surname>Felfernig</surname>
          </string-name>
          ,
          <string-name>
            <given-names>S.</given-names>
            <surname>Reiterer</surname>
          </string-name>
          ,
          <string-name>
            <given-names>F.</given-names>
            <surname>Reinfrank</surname>
          </string-name>
          , G. Ninaus, and
          <string-name>
            <given-names>M.</given-names>
            <surname>Jeran</surname>
          </string-name>
          , “Conflict Detection and Diagnosis in Configuration,” in KnowledgeBased Configuration: From Research to Business Cases,
          <string-name>
            <given-names>A.</given-names>
            <surname>Felfernig</surname>
          </string-name>
          ,
          <string-name>
            <given-names>L.</given-names>
            <surname>Hotz</surname>
          </string-name>
          ,
          <string-name>
            <given-names>C.</given-names>
            <surname>Bagley</surname>
          </string-name>
          , and J. Tiihonen, Eds. Morgan Kaufman,
          <year>2014</year>
          , pp.
          <fpage>73</fpage>
          -
          <lpage>87</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref3">
        <mixed-citation>
          [3]
          <string-name>
            <given-names>C.</given-names>
            <surname>Forza</surname>
          </string-name>
          and
          <string-name>
            <given-names>F.</given-names>
            <surname>Salvador</surname>
          </string-name>
          ,
          <article-title>Product information management for mass customization: connecting customer, front-office and back-office for fast and efficient customization</article-title>
          . New York: Palgrave Macmillan,
          <year>2007</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref4">
        <mixed-citation>
          [4]
          <string-name>
            <given-names>L.</given-names>
            <surname>Hvam</surname>
          </string-name>
          ,
          <string-name>
            <given-names>N. H.</given-names>
            <surname>Mortensen</surname>
          </string-name>
          , and
          <string-name>
            <given-names>J.</given-names>
            <surname>Riis</surname>
          </string-name>
          , Product customization. Springer Science &amp; Business
          <string-name>
            <surname>Media</surname>
          </string-name>
          ,
          <year>2008</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref5">
        <mixed-citation>
          [5]
          <string-name>
            <given-names>S.</given-names>
            <surname>Shafiee</surname>
          </string-name>
          ,
          <string-name>
            <given-names>L.</given-names>
            <surname>Hvam</surname>
          </string-name>
          , and
          <string-name>
            <given-names>M.</given-names>
            <surname>Bonev</surname>
          </string-name>
          , “
          <article-title>Scoping a product configuration project for engineer-to-order companies</article-title>
          ,”
          <source>International Journal of Industrial Engineering and Management</source>
          , vol.
          <volume>5</volume>
          , no.
          <issue>4</issue>
          , pp.
          <fpage>207</fpage>
          -
          <lpage>220</lpage>
          ,
          <year>2014</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref6">
        <mixed-citation>
          [6]
          <string-name>
            <given-names>A.</given-names>
            <surname>Felfernig</surname>
          </string-name>
          ,
          <string-name>
            <given-names>L.</given-names>
            <surname>Hotz</surname>
          </string-name>
          ,
          <string-name>
            <given-names>C.</given-names>
            <surname>Bagley</surname>
          </string-name>
          , and
          <string-name>
            <given-names>J.</given-names>
            <surname>Tiihonen</surname>
          </string-name>
          ,
          <article-title>Knowledge-Based Configuration From Research to Business Cases</article-title>
          . Newnes: Morgan Kaufman,
          <year>2014</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref7">
        <mixed-citation>
          [7]
          <string-name>
            <given-names>C.</given-names>
            <surname>Forza</surname>
          </string-name>
          and
          <string-name>
            <given-names>F.</given-names>
            <surname>Salvador</surname>
          </string-name>
          , “
          <article-title>Managing for variety in the order acquisition and fulfilment process: The contribution of product configuration systems</article-title>
          ,”
          <source>International Journal of Production Economics</source>
          , vol.
          <volume>76</volume>
          , no.
          <issue>1</issue>
          , pp.
          <fpage>87</fpage>
          -
          <lpage>98</lpage>
          , Mar.
          <year>2002</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref8">
        <mixed-citation>
          [8]
          <string-name>
            <given-names>S.</given-names>
            <surname>Shafiee</surname>
          </string-name>
          , “
          <article-title>Conceptual Modelling for Product Configuration Systems</article-title>
          ,” Technical University of Denmark,
          <year>2017</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref9">
        <mixed-citation>
          [9]
          <string-name>
            <given-names>A.</given-names>
            <surname>Haug</surname>
          </string-name>
          ,
          <string-name>
            <given-names>S.</given-names>
            <surname>Shafiee</surname>
          </string-name>
          , and L. Hvam, “
          <article-title>The costs and benefits of product configuration projects in engineer-to-order companies,” Computers in Industry</article-title>
          , vol.
          <volume>105</volume>
          , pp.
          <fpage>133</fpage>
          -
          <lpage>142</lpage>
          ,
          <year>2019</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref10">
        <mixed-citation>
          [10]
          <string-name>
            <given-names>A.</given-names>
            <surname>Haug</surname>
          </string-name>
          ,
          <string-name>
            <given-names>S.</given-names>
            <surname>Shafiee</surname>
          </string-name>
          , and L. Hvam, “
          <article-title>The causes of product configuration project failure,” Computers in Industry</article-title>
          , vol.
          <volume>108</volume>
          , pp.
          <fpage>121</fpage>
          -
          <lpage>131</lpage>
          ,
          <year>2019</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref11">
        <mixed-citation>
          [11]
          <string-name>
            <given-names>K.</given-names>
            <surname>Kristjansdottir</surname>
          </string-name>
          ,
          <string-name>
            <given-names>S.</given-names>
            <surname>Shafiee</surname>
          </string-name>
          ,
          <string-name>
            <given-names>L.</given-names>
            <surname>Hvam</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M.</given-names>
            <surname>Bonev</surname>
          </string-name>
          ,
          <article-title>and</article-title>
          <string-name>
            <given-names>A.</given-names>
            <surname>Myrodia</surname>
          </string-name>
          , “
          <article-title>Return on investment from the use of product configuration systems - A case study,” Computers in Industry</article-title>
          , vol.
          <volume>100</volume>
          , no.
          <source>July</source>
          <year>2017</year>
          , pp.
          <fpage>57</fpage>
          -
          <lpage>69</lpage>
          ,
          <year>2018</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref12">
        <mixed-citation>
          [12]
          <string-name>
            <given-names>S.</given-names>
            <surname>Shafiee</surname>
          </string-name>
          ,
          <string-name>
            <given-names>L.</given-names>
            <surname>Hvam</surname>
          </string-name>
          ,
          <string-name>
            <given-names>A.</given-names>
            <surname>Haug</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M.</given-names>
            <surname>Dam</surname>
          </string-name>
          , and
          <string-name>
            <given-names>K.</given-names>
            <surname>Kristjansdottir</surname>
          </string-name>
          , “
          <article-title>The documentation of product configuration systems: A framework and an IT solution</article-title>
          ,” Advanced Engineering Informatics, vol.
          <volume>32</volume>
          , pp.
          <fpage>163</fpage>
          -
          <lpage>175</lpage>
          ,
          <year>2017</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref13">
        <mixed-citation>
          [13]
          <string-name>
            <given-names>L.</given-names>
            <surname>Hvam</surname>
          </string-name>
          , “Mass customisation of process plants,”
          <source>International Journal of Mass Customisation</source>
          , vol.
          <volume>1</volume>
          , no.
          <issue>4</issue>
          , pp.
          <fpage>445</fpage>
          -
          <lpage>462</lpage>
          ,
          <year>2006</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref14">
        <mixed-citation>
          [14]
          <string-name>
            <given-names>A.</given-names>
            <surname>Haug</surname>
          </string-name>
          ,
          <string-name>
            <given-names>L.</given-names>
            <surname>Hvam</surname>
          </string-name>
          , and
          <string-name>
            <given-names>N. H.</given-names>
            <surname>Mortensen</surname>
          </string-name>
          , “
          <article-title>The impact of product configurators on lead times in engineering-oriented companies,” Artificial Intelligence for Engineering Design, Analysis and Manufacturing</article-title>
          , vol.
          <volume>25</volume>
          , no.
          <issue>02</issue>
          , pp.
          <fpage>197</fpage>
          -
          <lpage>206</lpage>
          , Apr.
          <year>2011</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref15">
        <mixed-citation>
          [15]
          <string-name>
            <given-names>L.</given-names>
            <surname>Hvam</surname>
          </string-name>
          ,
          <string-name>
            <given-names>A.</given-names>
            <surname>Haug</surname>
          </string-name>
          ,
          <string-name>
            <given-names>N. H.</given-names>
            <surname>Mortensen</surname>
          </string-name>
          , and
          <string-name>
            <given-names>C.</given-names>
            <surname>Thuesen</surname>
          </string-name>
          , “
          <article-title>Observed benefits from product configuration systems</article-title>
          ,”
          <source>International Journal of Industrial Engineering: Theory, Applications and Practice</source>
          , vol.
          <volume>20</volume>
          , no.
          <issue>5-6</issue>
          , pp.
          <fpage>329</fpage>
          -
          <lpage>338</lpage>
          ,
          <year>2013</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref16">
        <mixed-citation>
          [16]
          <string-name>
            <given-names>S.</given-names>
            <surname>Shafiee</surname>
          </string-name>
          ,
          <string-name>
            <given-names>K.</given-names>
            <surname>Kristjansdottir</surname>
          </string-name>
          ,
          <string-name>
            <given-names>L.</given-names>
            <surname>Hvam</surname>
          </string-name>
          , and
          <string-name>
            <given-names>C.</given-names>
            <surname>Forza</surname>
          </string-name>
          , “
          <article-title>How to scope configuration projects and manage the knowledge they require</article-title>
          ,
          <source>” Journal of Knowledge Management</source>
          , vol.
          <volume>22</volume>
          , no.
          <issue>5</issue>
          , pp.
          <fpage>982</fpage>
          -
          <lpage>1014</lpage>
          ,
          <year>2018</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref17">
        <mixed-citation>
          [17]
          <string-name>
            <given-names>T.</given-names>
            <surname>Pisello</surname>
          </string-name>
          , “IT Value Chain Management - Maximizing
          <source>the ROI from IT Investments,” Standish Report</source>
          ,
          <year>2003</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref18">
        <mixed-citation>
          [18]
          <string-name>
            <given-names>P. R.</given-names>
            <surname>Massingham</surname>
          </string-name>
          and
          <string-name>
            <given-names>R. K.</given-names>
            <surname>Massingham</surname>
          </string-name>
          , “
          <article-title>Does knowledge management produce practical outcomes?</article-title>
          ,
          <source>” Journal of Knowledge Management</source>
          , vol.
          <volume>18</volume>
          , no.
          <issue>2</issue>
          , pp.
          <fpage>221</fpage>
          -
          <lpage>254</lpage>
          ,
          <year>2014</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref19">
        <mixed-citation>
          [19]
          <string-name>
            <given-names>J.</given-names>
            <surname>Tiihonen</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M.</given-names>
            <surname>Heiskala</surname>
          </string-name>
          ,
          <string-name>
            <given-names>A.</given-names>
            <surname>Anderson</surname>
          </string-name>
          , and T. Soininen, “
          <article-title>WeCoTinA practical logic-based sales configurator</article-title>
          ,”
          <source>AI Communications</source>
          , vol.
          <volume>26</volume>
          , no.
          <issue>1</issue>
          , pp.
          <fpage>99</fpage>
          -
          <lpage>131</lpage>
          ,
          <year>2013</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref20">
        <mixed-citation>
          [20]
          <string-name>
            <given-names>A.</given-names>
            <surname>Haug</surname>
          </string-name>
          , “
          <article-title>A software system to support the development and maintenance of complex product configurators,”</article-title>
          <source>The International Journal of Advanced Manufacturing Technology</source>
          , vol.
          <volume>49</volume>
          , no.
          <issue>1-4</issue>
          , pp.
          <fpage>393</fpage>
          -
          <lpage>406</lpage>
          , Nov.
          <year>2009</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref21">
        <mixed-citation>
          [21]
          <string-name>
            <given-names>M.</given-names>
            <surname>Alqudah</surname>
          </string-name>
          and
          <string-name>
            <given-names>R.</given-names>
            <surname>Razali</surname>
          </string-name>
          , “
          <article-title>A comparison of scrum and Kanban for identifying their selection factors</article-title>
          ,
          <source>” Proceedings of the 2017 6th International Conference on Electrical Engineering and Informatics: Sustainable Society Through Digital Innovation, ICEEI</source>
          <year>2017</year>
          , vol. 2017-Novem, no.
          <source>April</source>
          <year>2018</year>
          , pp.
          <fpage>1</fpage>
          -
          <lpage>6</lpage>
          ,
          <year>2018</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref22">
        <mixed-citation>
          [22]
          <string-name>
            <given-names>S.</given-names>
            <surname>Shafiee</surname>
          </string-name>
          , “
          <article-title>An agile documentation system for highly engineered, complex product configuration systems</article-title>
          ,
          <source>” Proceedings of the 22nd Euroma Conference</source>
          ,
          <year>2015</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref23">
        <mixed-citation>
          [23]
          <string-name>
            <given-names>S.</given-names>
            <surname>Shafiee</surname>
          </string-name>
          ,
          <string-name>
            <given-names>L.</given-names>
            <surname>Hvam</surname>
          </string-name>
          ,
          <string-name>
            <given-names>A.</given-names>
            <surname>Haug</surname>
          </string-name>
          , and
          <string-name>
            <given-names>Y.</given-names>
            <surname>Wautelet</surname>
          </string-name>
          , “
          <source>Behavior-Driven Development in Product Configuration Systems,” in 20th Configuration Workshop</source>
          ,
          <year>2018</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref24">
        <mixed-citation>
          [24]
          <string-name>
            <given-names>A.</given-names>
            <surname>Haug</surname>
          </string-name>
          and
          <string-name>
            <given-names>L.</given-names>
            <surname>Hvam</surname>
          </string-name>
          , “
          <article-title>The Modelling Techniques of a Documentation System that Supports the Development and Maintenance of Product Configuration Systems</article-title>
          ,”
          <source>International Journal of Mass Customisation</source>
          , vol.
          <volume>2</volume>
          , no.
          <issue>1-2</issue>
          , pp.
          <fpage>1</fpage>
          -
          <lpage>18</lpage>
          ,
          <year>2007</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref25">
        <mixed-citation>
          [25]
          <string-name>
            <given-names>B. P.</given-names>
            <surname>Lientz</surname>
          </string-name>
          ,
          <string-name>
            <given-names>E. B.</given-names>
            <surname>Swanson</surname>
          </string-name>
          , and
          <string-name>
            <given-names>G. E.</given-names>
            <surname>Tompkins</surname>
          </string-name>
          , “
          <article-title>Characteristics of application software maintenance,” Communications of the ACM</article-title>
          , vol.
          <volume>21</volume>
          , no.
          <issue>6</issue>
          , pp.
          <fpage>466</fpage>
          -
          <lpage>471</lpage>
          ,
          <year>2002</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref26">
        <mixed-citation>
          [26]
          <string-name>
            <given-names>T.</given-names>
            <surname>Blecker</surname>
          </string-name>
          ,
          <string-name>
            <given-names>N.</given-names>
            <surname>Abdelkafi</surname>
          </string-name>
          ,
          <string-name>
            <given-names>B.</given-names>
            <surname>Kaluza</surname>
          </string-name>
          , and G. Friedrich, “
          <article-title>Controlling variety-induced complexity in mass customisation: a key metricsbased approach</article-title>
          ,”
          <source>International Journal of Mass Customisation</source>
          , vol.
          <volume>1</volume>
          , no.
          <issue>2</issue>
          , pp.
          <fpage>272</fpage>
          -
          <lpage>298</lpage>
          ,
          <year>2006</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref27">
        <mixed-citation>
          [27]
          <string-name>
            <given-names>A.</given-names>
            <surname>Felfernig</surname>
          </string-name>
          ,
          <string-name>
            <given-names>G.</given-names>
            <surname>Friedrich</surname>
          </string-name>
          ,
          <string-name>
            <given-names>D.</given-names>
            <surname>Jannach</surname>
          </string-name>
          , and
          <string-name>
            <given-names>M.</given-names>
            <surname>Stumptner</surname>
          </string-name>
          , “
          <article-title>Consistency-based diagnosis of configuration knowledge bases</article-title>
          ,
          <source>” Artificial Intelligence</source>
          , vol.
          <volume>152</volume>
          , no.
          <issue>2</issue>
          , pp.
          <fpage>213</fpage>
          -
          <lpage>234</lpage>
          , Feb.
          <year>2004</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref28">
        <mixed-citation>
          [28]
          <string-name>
            <given-names>A.</given-names>
            <surname>Even</surname>
          </string-name>
          and G. Shankaranarayanan, “
          <article-title>Utility-driven configuration of data quality in data repositories</article-title>
          ,”
          <source>International Journal of Information Quality</source>
          , vol.
          <volume>1</volume>
          , no.
          <issue>1</issue>
          , pp.
          <fpage>22</fpage>
          -
          <lpage>40</lpage>
          ,
          <year>2007</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref29">
        <mixed-citation>
          [29]
          <string-name>
            <given-names>B.</given-names>
            <surname>Renzl</surname>
          </string-name>
          , “
          <article-title>Trust in management and knowledge sharing: The mediating effects of fear and knowledge documentation,” Omega</article-title>
          , vol.
          <volume>36</volume>
          , no.
          <issue>2</issue>
          , pp.
          <fpage>206</fpage>
          -
          <lpage>220</lpage>
          , Apr.
          <year>2008</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref30">
        <mixed-citation>
          [30]
          <string-name>
            <given-names>J.</given-names>
            <surname>Tiihonen</surname>
          </string-name>
          ,
          <string-name>
            <given-names>T.</given-names>
            <surname>Soininen</surname>
          </string-name>
          ,
          <string-name>
            <given-names>T.</given-names>
            <surname>Männistö</surname>
          </string-name>
          , and
          <string-name>
            <given-names>R.</given-names>
            <surname>Sulonen</surname>
          </string-name>
          , “
          <article-title>State-of-thePractice in Product Configuration - A Survey of 10 Cases in the Finnish Industry,” in Knowledge Intensive CAD,</article-title>
          <year>1996</year>
          , vol.
          <volume>1</volume>
          , pp.
          <fpage>95</fpage>
          -
          <lpage>114</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref31">
        <mixed-citation>
          [31]
          <string-name>
            <surname>A. B. Brown</surname>
            , A. Keller, and
            <given-names>J. L.</given-names>
          </string-name>
          <string-name>
            <surname>Hellerstein</surname>
          </string-name>
          , “
          <article-title>A Model of Configuration Complexity and its Application to a Change Management System Aaron,” IEEE Transactions on Network and Service Management</article-title>
          , vol.
          <volume>4</volume>
          , no.
          <issue>1</issue>
          , pp.
          <fpage>13</fpage>
          -
          <lpage>27</lpage>
          , Jun.
          <year>2007</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref32">
        <mixed-citation>
          [32]
          <string-name>
            <surname>A. H. Van de Ven</surname>
          </string-name>
          , “
          <article-title>Nothing is quite so practical as a good theory,” Academy of Management Review</article-title>
          , vol.
          <volume>14</volume>
          , no.
          <issue>4</issue>
          , pp.
          <fpage>486</fpage>
          -
          <lpage>489</lpage>
          ,
          <year>1989</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref33">
        <mixed-citation>
          [33]
          <string-name>
            <surname>D. M. McCutcheon</surname>
            and
            <given-names>J. R.</given-names>
          </string-name>
          <string-name>
            <surname>Meredith</surname>
          </string-name>
          , “
          <article-title>Conducting case study research in operations management</article-title>
          ,
          <source>” Journal of Operations Management</source>
          , vol.
          <volume>11</volume>
          , no.
          <issue>3</issue>
          , pp.
          <fpage>239</fpage>
          -
          <lpage>256</lpage>
          ,
          <year>1993</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref34">
        <mixed-citation>
          [34]
          <string-name>
            <given-names>B. B. B.</given-names>
            <surname>Kaplan</surname>
          </string-name>
          and
          <string-name>
            <given-names>D.</given-names>
            <surname>Duchon</surname>
          </string-name>
          , “
          <source>Combining Qualitative and Quantitative Methods in Information Systems Research: A Case Study.,” MIS Quarterly</source>
          , vol.
          <volume>12</volume>
          , no.
          <issue>4</issue>
          , pp.
          <fpage>571</fpage>
          -
          <lpage>586</lpage>
          ,
          <year>1988</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref35">
        <mixed-citation>
          [35]
          <string-name>
            <given-names>J.</given-names>
            <surname>Meredith</surname>
          </string-name>
          , “
          <article-title>Building operations management theory through case and field research</article-title>
          ,
          <source>” Journal of Operations Management</source>
          , vol.
          <volume>16</volume>
          , no.
          <issue>4</issue>
          , pp.
          <fpage>441</fpage>
          -
          <lpage>454</lpage>
          ,
          <year>1998</year>
          .
        </mixed-citation>
      </ref>
    </ref-list>
  </back>
</article>