=Paper=
{{Paper
|id=Vol-1220/paper11
|storemode=property
|title=Open Configuration: a New Approach to Product Customization
|pdfUrl=https://ceur-ws.org/Vol-1220/11_confws2014_submission_4.pdf
|volume=Vol-1220
|dblpUrl=https://dblp.org/rec/conf/confws/ZhangCFC14
}}
==Open Configuration: a New Approach to Product Customization==
https://ceur-ws.org/Vol-1220/11_confws2014_submission_4.pdf
Open Configuration: a New Approach to Product
Customization
Linda L. Zhang1 and Xiaoyu Chen*1, 2 and Andreas Falkner3 and Chengbin Chu2
Abstract.1 State-of-the-art product configuration enables components in addition to the predefined ones. In another word, it
companies to deliver customized products by selecting and cannot configure customized products in a true sense, i.e., to the
assembling predefined configuration elements based on known full extent that it covers all reasonable and unforeseen customer
relationships. This paper introduces an innovative concept, open requirements.
configuration, in order to assist companies in configuring products
This study proposes an innovative concept ‘open configuration’
that correspond exactly to what customers want. Superior to
product configuration, open configuration involves both predefined in order to help companies configure such products that can meet
configuration elements and new ones in configuring customized both predefined and unforeseen customer requirements, that is, to
products. As a first step, this study explains the concept of open meet customer requirements as complete as possible without
configuration and the basic principles. It also discusses in detail the making too much compromise (see Section 2). In this regard, in
challenges involved in open configuration, such as conceptual configuring customized products, open configuration deals with
model development, open configuration optimization, and open not only the addition of new configuration elements, such as
configuration knowledge representation. functions, components, but also the modification of existing
configuration elements, more specifically components. Existing
component modification is to accommodate the integration of new
1 INTRODUCTION components with the predefined ones.
With the advancement of design and manufacturing technologies, In the rest of this paper, Section 2 uses a fridge configuration
customers are no longer satisfied with standardized products. They example to illustrate the limitation of product configuration, i.e.,
increasingly demand products that could satisfy their individual the product configured lie in a known range in accordance with the
needs. As a result, companies need to timely offer customized predefined components. Section 3 introduces the concept of open
products at affordable costs to survive [1]. With traditional design configuration, its basic principles, and its process. Section 4 sheds
approaches, companies cannot efficiently develop customized lights on the challenges involved in open configuration. We end the
products [2, 3]. Product configuration has been proposed to enable paper in Section 5 by pointing out the ongoing research that we are
companies to deliver customized products at low costs with short working on.
delivery times. Product configuration has been widely applied to a
variety of industries, including computer, telecommunication
systems, transportation, industrial products, medical systems and 2 PRODUCT CONFIGURATION
services [4]. It brings companies a number of advantages in As a special design activity, product configuration capitalizes on
delivering required products. These advantages include managing design results, such as components, attributes and their
product variety [5], shortening delivery time [6], improving relationships [9, 10]. It entails such a process that based on given
product quality [7], simplifying order acquisition and fulfilment customer requirements, suitable components are selected from the
activities [8], etc. set of predefined component types; the selected components are
Product configuration has received much attention from evaluated and further arranged into products according to the
industrial and academia alike. Researchers have approached configuration constraints and rules.
product configuration from different perspectives and have Take fridge configuration as an example. Assume in this
developed diverse methods, methodologies, approaches, and example, there are 6 component types, including Refrigerator (R),
algorithms to solve different configuration issues and problems. In Freezer (F), Freezer drawer (Fd), Variable compartment (V), Base
spite of the diversities among these solution tools, they are (B), Outer casing (O). Each component type is defined by a set of
developed based on a common assumption: the configuration attributes (number, size, price) and each attribute can assume a
elements, such as components, modules, attributes, functions, and number of values. Table 1 summarizes these component types, the
their relationships are predefined. In relation to this assumption, the attributes, and attribute values.
products that can be configured are known in principle even if not For example, N R : (1, 2) represents the number of Refrigerators
explicitly listable [2]. In this regard, product configuration cannot in one fridge can be 1 or 2; SR : (small, medium, large, extra-large)
deal with such products that demand new functions and indicates the component Refrigerator has four different sizes:
small, medium, large, extra-large. Price mentioned hereinafter
1
IESEG School of Management (LEM-CNRS), Lille-Paris, France states the price of the configured fridge.
2
Ecole Centrale Paris (Laboratoire Genie Industriel), Paris, France
3
Siemens AG Österreich, Vienna, Austria
*
Corresponding author: x.chen@ieseg.fr
Table 1. The attributes of the fridge components. {R :1,large; NF 1;min P} . The configured fridge must satisfy these
Component types Number Size Price constraints and additional rules mentioned earlier while fulfilling
small, medium, the customer requirements. In this regard, the constraints
Refrigerator 1-2 depending on size
large, extra-large {R :1,large} and {N F 1} limit the possible choices to: {FCc , FCe } ,
small, large, i.e., the configuration solutions shown in Figs. 1.c and 1.e. The cost
Freezer 0-1 depending on size
extra-large
constraint {min P} indicating the minimal price results in the final
P(Fd) ( i.e., a fixed
Freezer drawer 0-2 small solution to be FCc {R :1,large ; F :1,small ; B :1,standard ; O :1,
price)
standard } .
Variable P(V) (i.e., a fixed
0-1 small As only predefined elements are involved, product
compartment price)
Base 1 standard, wide depending on size configuration fails to provide customized products in a true sense
Outer casing 1 standard, wide depending on size or provides these products which can meet unforeseen customer
requirements. Take the above fridge configuration as an example.
Suppose that the requirements from another customer include any
There are relationships among components, among attributes,
of the following:
and between components and attributes. For examples,
a fridge consisting of only one medium refrigerator,
{SR large, NF 1} {SF small} means if one large sized
a fridge consisting of 2 freezers,
Refrigerator and one Freezer are selected, the size of the Freezer is
an outer casing with a special color, and
small; NFd 0 {NR 2, SR medium} states that if the component
a cheaper fridge to be moved easily and with at least one
Freezer drawer is selected then two medium Refrigerators are
freezer drawer.
required. The other relationships include: {SR medium, NF 0}
In general, the first two requirements violate some predefined
N R 2 ; {SF small, SR small} NV 1 ; {SR extra-large, NF 1}
constraints (although the first one requires a new - lower - type of
{SF extra-large} ; {SF extra-large} {SB wide, SO wide} ;
outer casing as a side-effect); the last two introduce new concepts.
{NV 1,NF 0} {NR 1, SR large,SV small} ; {S R small, N F 1}
In more detail, the third requirement requires a new attribute value
{S F large} .
for the component outer casing. The last one is more complex. A
There are four additional rules, including (1) ( NR NV NF ) 3 ,
part of it, i.e., being cheaper and with one freezer drawer, can be
meaning the total number of Refrigerator, Variable compartment,
fulfilled by the predefined functions and components, while the
and Freezer in one fridge should be no more than 3, (2)
rest cannot be fulfilled by the available functions, thus calling for a
NR 2 NV NF 0 , indicating if two Refrigerators are selected,
new function: ‘to be movable’. This new function, in turn, needs
the number of Freezer and Variable compartment is zero, (3)
new components, such as ‘wheels’, ‘brakes’, etc., which are
N Fd N F 0 representing that Freezer cannot be selected together
necessary for delivering this function. Because of the lack of these
with Freezer drawer, and (4) N Fd NV 0 indicating that Freezer
components, product configuration can provide the customer with
drawer cannot be selected together with Variable compartment.
one of the fridges shown in Fig. 1 without satisfying all his
According to the above pre-defined components and their
requirements. The customer, thus, has to accept this fridge by
relationships, only 17 fridge configurations are available as
making compromise (e.g., accept a cheapest fridge with a freezer
possible solutions. While Fig. 1 shows 8 fridge configurations due
drawer, which cannot be moved easily).
to the space issue, different positions of components in Fig. 1.c,
Fig. 1.d, Fig. 1.e, Fig. 1.f, and Fig. 1.g lead to the other 9 fridge
configurations. All customized fridges to be configured based on 3 OPEN CONFIGURATION
customer requirements fall into this range of configuration
solutions. (Note: Fridges from the left to the right are arranged In order to help companies configure customized products that
based on the increase of price.) Take fridge f in Fig. 1 as an correspond exactly to what a customer requires, this paper puts
example to explain the components and their attributes in the forward the concept of open configuration. The basic principle and
configuration solution. This fridge configuration is represented as general process of open configuration are introduced below.
FC f {R :1,small ; V :1,small ;F :1,small ;B :1,standard ; O :1,standard} .
It has one small Refrigerator on top, one small Variable
compartment in the middle, one small Freezer at the bottom, one
3.1 Open configuration concept
standard Base, and one standard Outer casing. Built on top of product configuration, open configuration is to
configure customized products to meet customer requirements in a
true sense. Similar as product configuration, it utilizes design
Variable Refrigerator
Refrigerator
Freezer compartment
Freezer
Refrigerator results, selects components, and arranges the selected components
Freezer
Refrigerator
Variable Refrigerator according to constraints and rules. In extension to product
compartment
Refrigerator Refrigerator Refrigerator
Refrigerator
configuration, it involves new component design, more specifically
Refrigerator Freezer
the specification of functions and the selection of the
Freezer
drawer corresponding components. In addition, it deals with the
a b c d e f g h
modification of the predefined components, which allows the
integration of new configuration elements.
Figure 1. Fridge configuration solutions
Suppose the requirements from a customer include a cheaper
3.2 Open configuration overview and process
fridge with a freezer and a large refrigerator. In accordance with Open configuration involves two types of knowledge: predefined
these requirements, the constraints can be modeled as knowledge and dynamic knowledge. Predefined knowledge relates
to predefined functions, components, and relationships; dynamic carried out. The selected components are arranged into product
knowledge is associated with newly defined elements. In relation configuration alternatives by following the product structure
to these customer requirements, which can be fulfilled by the described in the dynamic and predefined knowledge. These
predefined functions (i.e., Type Ⅰ requirements in Fig. 2), the configuration alternatives are further evaluated under certain
corresponding components are selected, while for these criteria. Based on the evaluation results, the optimal one or
requirements, which cannot be fulfilled by the predefined functions multiple are suggested to customers.
(i.e., Type Ⅱ requirements in the figure), new functions and
corresponding components are specified. The specification of these
new configuration elements contributes to the extension of the 4 CHALLENGES INVOLVED IN OPEN
dynamic knowledge. The relationships among the predefined CONFIGURATION
elements and the newly defined elements are specified as well. In accordance with the involvement of new configuration elements,
This specification contributes to the interaction between the open configuration changes the basic assumptions and reasoning
predefined knowledge and the dynamic knowledge. By respecting processes of product configuration. In this regard, there are a
the constraints embedded in both the predefined and dynamic number of potential challenges involved in open configuration.
knowledge, all necessary components are selected, modified, and Due to the page limitation, this paper discusses five of these
arranged into a customized product. challenges, including open configuration modeling, system design
and development, open configuration solving, open configuration
Type Ⅰ Predefined optimization, and open configuration knowledge representation.
requirements knowledge
Customer Customized
requirements products
4.1 Open configuration modeling
Type Ⅱ Dynamic
requirements knowledge
Open configuration modeling addresses the modeling of open
configuration knowledge and the reasoning mechanism for using
the configuration knowledge. The modeling of open configuration
Figure 2. Open configuration overview knowledge is to model configuration elements, constraints, and
rules. It involves two kinds of knowledge: predefined knowledge
In more detail, suppose that given customer requirements are and dynamic knowledge. A product model and corresponding
valid, complete and do not conflict with one another. These functional architectures should be developed for defining and
requirements are evaluated first to determine whether or not they further classifying the two different types of knowledge. The
can be fulfilled by the available configuration elements (i.e., modeling of the reasoning mechanism is to shed light on (1) how
functions and components). According to the evaluation results, new functions are specified, (2) how new components are
these requirements are classified into Type Ⅰ and Type Ⅱ determined, and (3) how components are selected and arranged
requirements. Fig. 3 summarizes this process. into products.
Components
In open configuration modeling, the components and functions
Type Ⅰ
requirements
selection are characterized by their attributes, while the inter-connections
Components
Yes
modification Final components
selection
Components
arrangement
among the components are represented by connections and ports.
Customer All required
The modeling of the dynamic knowledge needs to take into
requirements
evaluation
configuration elements
available
Configured alternatives
evaluation
account the fact that new functions and components are added
No based on the unforeseen customer requirements. Thus, its modeling
New New Customized
Type Ⅱ
requirements
functions components
specification
products involves newly-added concepts, constraints, and rules. The
specification
modeling of the predefined knowledge needs to consider these
predefined components, modified components, and their
Figure 3. Open configuration process relationships. The interaction between predefined knowledge and
dynamic knowledge needs to be modeled as well.
For Type Ⅱ requirements, new functions are specified and all Open configuration modeling is more sophisticated than
possible components which can realize these functions are configuration modeling due to the involvement of the dynamic
subsequently determined. Also specified are the relationships knowledge. In this regard, it is interesting to see whether or not
among functions, among components, and between functions and these techniques which are suitable for modeling product
components. This process contributes to the extension of the configuration (e.g., Unified Modeling Language (UML), Alloy,
dynamic knowledge. For Type Ⅰ requirements, all possible and generative Constraint Satisfaction Problem (CSP) [11]) can be
components are selected from the predefined ones. In addition, to used to model open configuration. If these techniques are feasible,
be compatible with the newly introduced components, some how can they be modified or adjusted to model open configuration.
predefined components are modified by respecting constrains and If these techniques are not feasible, new modeling formalisms and
rules embedded in the predefined and dynamic knowledge. This constructs are to be developed.
process reflects the interaction between the dynamic and
predefined knowledge. From the modified components, newly
introduced components, and selected predefined components, 4.2 System design and development
suitable components are further selected for forming configuration
System design and development for open configuration refers to
alternatives, which can meet customer requirements. In the
the design and development of the computer information system to
selection, consistency and compatibility evaluations might be
implement open configuration, i.e., open configurators. Open
configurators consist of a customer input module which deals with and configuration rules. To solve this model, algorithms need to be
customer requirements evaluation, open configuration knowledge developed subsequently.
bases, reasoning and evaluation mechanisms, optimization and In the situation that customer requirements demand new
diagnosis mechanisms, and an output module which communicates functions, the dynamic knowledge will be specified. The modeling
the configuration results with users. Different from product of open configuration problem will associate with the interaction
configurators, open configurators involve two knowledge bases: a between the customer requirements and two types of knowledge
knowledge base for the predefined knowledge and the other for the (predefined knowledge and dynamic knowledge). The main
dynamic knowledge. Joint reasoning mechanisms between the two difficulties are (1) the modeling of new function specification, (2)
knowledge bases are required, which mainly associate with the modeling of new components selection according to the
interacting and integrating elements from the two knowledge bases. customer requirements, (3) and the modeling of the interaction
For the dynamic knowledge base, new elements design modules between new components and selected existing components. After
are needed to develop and maintain this knowledge base. The new modeling an open configuration problem, suitable algorithms need
elements design modules include the module for specifying new to be developed to solve the model. Because of the differences
functions with respect to the requirements, the module for selecting between product configuration and open configuration and the
new components to fulfill new functions and the module for corresponding differences between a product configuration model
interfacing with the predefined elements. For the predefined and an open configuration model, these algorithms, which are
knowledge base, different from product configurators, there need suitable for product configuration solving, may not be applicable
to be a modification module for modify existing components to be for open configuration solving. Thus, new algorithms are to be
compatible with the new ones. developed.
In designing and developing open configurators, the techniques
should have the ability to model dynamic knowledge and the
interaction between dynamic knowledge and predefined 4.5 Open configuration optimization
knowledge. In this regard, the available system design techniques During each step of open configuration, optimal functions,
for product configuration may need to be modified in designing components and structures need to be specified from a number of
and developing open configurators. alternatives. The dynamic feature of open configuration increases
the degree of difficulty in optimizing the new functions, new
components, and the interaction between new components and
4.3 Open configuration knowledge
predefined ones. In this regard, an explicit optimization mechanism
representation needs to be developed.
Open configuration knowledge representation entails the effective In accordance with the open configuration process discussed
organization of open configuration knowledge, including the earlier, the optimization mechanism should evaluate the
predefined and dynamic knowledge. It logically uniforms the open configuration elements at three levels. In the first level, the
configuration knowledge and enables the utilization of the mechanism should evaluate all the possible function alternatives
knowledge in different configuration tasks. for fulfilling Type II requirements and decide on the optimal ones.
The representation of open configuration knowledge includes This optimization might be based on, e.g., the performance and
the representation of predefined components, relationships, completeness of these function alternatives. In the second level, the
constraints and rules; the representation of newly-added mechanism should evaluate all the possible component alternatives
components, relationships, constraints and rules; and the for delivering the determined new functions and decide on the
representation of the constraints and relationships between optimal ones. This optimization may take into account, e.g., the
predefined knowledge and newly added knowledge. From the compatibility among the new components and the interaction with
experience of the knowledge representation for product predefined components. In the third level, the mechanism should
configuration, open configuration should be considered as both a evaluate all the product configuration alternatives and decide on
classification problem (i.e., capturing the aspects of taxonomy and the optimal ones. This optimization may consider, e.g., product
topology) and a constraint satisfaction problem (i.e., capturing the reliability.
aspects of constraints and resource balancing). Considering the
dynamic and indeterminate feature of open configuration, it might
be potentially challenging to capture different aspects of open 5 CONCLUSION
configuration knowledge (e.g., taxonomy, topology, constraints, In response to the limitation of product configuration, this paper
and resource balancing) in one model. Further studies may try to proposed open configuration to help design customer-driven
design new models (or sub models to be embedded in the available product in a true sense. It introduced the concept and process of
tools) separately on each aspect and joint them together to open configuration. It also discussed several challenges involved in
represent the knowledge. open configuration. Currently, we are working on the formulation
of open configuration. In the formulation, new components,
relationships among new components, and relationships between
4.4 Open configuration solving new components and existing components will be defined and
Open configuration solving relates to the development and modeled. This formulation is to rigorously define open
application of algorithms or other tools to solve open configuration configuration and shed light on the reasoning behind open
problems. In solving an open configuration problem, the problem configuration.
needs to be modeled first with respect to customer requirements
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