Service-oriented business to business integration: a ...

Service-oriented business to business integration: a systematic literature analysis Ilkka Melleri∗ , Kari Hiekkanen∗ , Juha Mykk¨anen† , ∗ Aalto

University School of Science and Technology Software Business and Engineering Institute {firstname.lastname}@tkk.fi † University of Eastern Finland Department of Computer Science, HIS R&D Unit {firstname.lastname}@uef.fi

Abstract—Business automation continues to be a strategic target for IT investment. However, business automation involves inherent challenges, such as system integration issues. ServiceOriented Architecture (SOA) and business-to-business (B2B) integration standards are two approaches used for creating business automation solutions. In this paper a systematic literature analysis is conducted to explore the integration concepts in these two approaches. The objective of the study is to characterize the integration issues in these approaches, and to synthesize the findings into characteristics of so called service-oriented B2B integration. From the literature it is concluded that the SOA approach emphasizes support for dynamic business processes within an enterprise, while the B2B standards approach focuses on pre-defined semantic descriptions of business data that is exchanged between business partners. Thus, a service-oriented B2B integration environment is conceptualized where the B2B standards are used to strengthen the semantic interoperability, while dynamic business process implementations are enabled through the SOA approach.

Keywords: Service-Oriented Architecture, B2B integration standards, system integration, systematic literature analysis. I. I NTRODUCTION A. Background Automating business functions with information technology continues to be an important target for strategic IT investment. However, creating business automation solutions is challenging due to many organizational and technological reasons [1]. One such challenge is system integration, which is an inherent part of building enterprise systems [2]. The reason for this is that organizations and systems are heterogeneous, autonomous and distributed in nature and therefore integration solutions are needed to make them interoperable [2]. A related concept to system integration is business integration, which aims at supporting collaboration between business entities by creating an agile and coherent environment [3]. In this paper system integration is seen as a subset, or a view point, of business integration, with focus on the technological side of the issue. With regard to system integration two typical approaches are the business-to-business (B2B) integration standards approach [4] and the enterprise application integration (EAI) approach [5].

Traditionally, both the B2B standards approach and the EAI approach, have been characterized by the use of proprietary network protocols and data formats [4], [5]. The development and evolution of the Web as a global and ubiquitous communication infrastructure has enhanced the possibilities for business automation [4]. With the Web as a world-wide infrastructure platform for electronic communication, it is in general possible for any businesses to share information with other parties. Therefore, using the Web for B2B communication has increased [4]. Furthermore, the Web technologies have also been adopted within enterprises, thus creating opportunities for evolution of the EAI approaches to utilize the Web [5]. The B2B standards approach has evolved to increasing use of XML-based B2B standards, such as the Electronic Business Using XML (ebXML)1 [4]. The main driver in this development has been to address the limitations of proprietary protocols and the rigid and inflexible structure of the EDI-style standards [4]. The EAI approach has evolved towards increasing use of XML-based Web Services (WS) technologies [5]. This has, in turn, opened possibilities to implement so called Serviceoriented architectures (SOA) [5], [6]. The SOA approach is based on the notion of serviceoriented computing, where the design of a dynamic and flexible IT infrastructure is based on combining independent components of computing logic called services [7]. Even though the SOA approach in general is agnostic to specific technologies, the WS technologies are currently the mainstream choice for implementing enterprise-level SOA systems [6]. There are a lot of publications discussing both B2B standards and SOA. However, it seems that much of the literature is fragmented so that B2B and SOA issues are analyzed somewhat in isolation. The B2B standards literature focuses on semantic aspects of business data between trading partners, whereas the SOA literature focuses on technical issues, with less attention to 1 http://ebxml.xml.org/

business semantics. Therefore, it could be useful to analyze the SOA and B2B literature with a systematic approach, in order to highlight relevant issues relating to service-oriented B2B integration. This paper attempts to contribute with a systematic literature analysis focusing on the integration aspects of SOA by using the B2B standards approach as a framework for analysis. B. Research objective and research question In this paper we set out to explore and compare the two approaches used for business automation, namely the B2B standards approach and the SOA approach. The objective is to highlight the characteristics of integration in the B2B standards approach and in the SOA approach. Through these characteristics we aim to synthesize the findings into characteristics of what is in this paper referred to as service-oriented B2B integration. To reach the research objective, a research question along with two sub-questions were formed. The research question and the sub-questions for this study are: 1) What are the characteristics of service-oriented B2B integration? a) What are characteristics of B2B integration standards? b) What are characteristics of SOA integration? The approach in this paper is to first answer the subquestions by highlighting relevant concepts of the two approaches. These concepts are then combined into characteristics of the two approaches. Finally, these characteristics are used to formulate a synthesized characterization of serviceoriented B2B integration, thus addressing the research question. C. Structure of the paper The paper is structured as follows. Section II presents in detail the research methodology used in this paper. In sections III and IV the identified concepts for the B2B integration standards and the SOA approach are presented and discussed. Section V provides the discussion and synthesis of, first, the characteristics of the B2B integration standards approach and the SOA approach, and then the synthesized characteristics of service-oriented B2B integration. Finally, in section VI the paper is concluded along with suggestions for further research. II. M ETHODOLOGY A. Introduction The research methodology used in this paper follows the systematic literature review methodology described in [8]. In essence, the methodology consists of three phases: literature search, literature selection and literature analysis. How these phases were implemented in this study are described in the following subsections.

TABLE I S ELECTED JOURNALS . Source

Years

VLDB Journal

2010-2007

Impact factor 7.067

MIS Quarterly

2010-2007

5.183

Communications of the ACM

2010-2007

2.646

Information & Management

2010-2007

2.358

Journal of Systems and Software

2010-2007

1.241

Computer Standards & Interfaces

2010-2007

1.074

TABLE II S ELECTED CONFERENCE PROCEEDINGS . Source

Years

Acceptance rates

IEEE International Conference on ServiceOriented Computing and Applications (SOCA)

2009, 2007

0.484 (2007), 0.350 (2009)

IEEE Conference on Commerce and Enterprise Computing (CEC)

2009-2007

0.214 (2009), 0.310 (2008), 0.257 (2007)

IEEE International Conference on Services Computing (SCC)

2009-2007

0.189 (2009), 0.194 (2008), 0.196 (2007)

World Wide Web conference

2009-2007

0.241 (2009), 0.117 (2008), 0.147 (2007)

B. Literature search and selection The methodology suggests to start the literature search process by going through selected journals and conference proceedings [8]. For this paper, six journals and four conference proceedings where selected as the initial sources. The selection criteria for journals were the journal impact factor2 and the topic of the journal. Because the topic of this paper is related both to technological and business issues, a balance between the two was sought for. However, the emphasis was on topics addressing technological issues in supporting business, rather than on purely managerial issues. The conference proceedings were selected primarily to find articles related to SOA issues and technologies. The premise was that this more novel topic would be covered less in journals. For conference proceedings, the article acceptance rate was used as an assessment for the quality of the source. The selected journals along with their impact factors are presented in table I, and the conference proceedings along with their article acceptance rates are presented in table II. The criteria for including a paper in this review were: topic balance (between SOA papers and B2B standards papers), and quality of the source (impact factor or acceptance rate). This means that in the article selection process, the articles were first categorized into three categories, SOA papers, B2B papers and combined SOA and B2B papers. This categorization was based on the abstracts and the keywords of the papers, so that those papers that emphasized either the SOA or the B2B approach were in the first two categories, and those 2 http://admin-apps.isiknowledge.com/JCR

TABLE III S UMMARY OF THE LITERATURE SELECTION Reference

Author

Selection type

Category

[2]

Bussler

Text book

B2B

[3]

Keller et al.

Conference proceedings

Combined

[4]

Medjahed, et al.

Citation analysis

B2B

[6]

Papazoglou, et al.

Journals

SOA

[7]

Erl

Text book

SOA

[9]

Razinkov, et al.

Journals

SOA

[10]

Lampathaki, et al.

Journals

B2B

[11]

Kilov, et al.

Journals

Combined

[12]

Umar, et al.

Journals

SOA

[13]

Egyedi, et al.

Journals

B2B

[14]

Nurmilaakso, et al.

Journals

B2B

[15]

Vitvar, et al.

Conference proceedings

Combined

[16]

Zhao, et al.

Journals

Combined

[17]

Guijarro, et al.

Journals

Combined

[18]

Schuster and Motal

Conference proceedings

Combined

[20]

Arsanjani, et al.

Citation analysis

SOA

[21]

Bussler

Citation analysis

Combined

[19]

Tan et al.

Conference proceedings

B2B

details on how to actually construct the matrix. For this paper, concept matrices were developed by first creating mind map summaries of the material. The mind maps were created with the Mindjet MindManager3 software. For identifying the concepts, we identified two possible strategies. The first strategy would be to look at the literature for both the SOA and the B2B standards approaches and try to find concepts addressed in both. The second strategy would be to choose either one of the two approaches, identify concepts in that approach, and use those concepts as a framework for identifying concepts in the other approach. The main challenge in the first strategy is to find concepts that are at the same level of abstraction and address similar issues in both approaches. Therefore, the second strategy seemed to be more suitable for this paper, and the more focused B2B standards approach was chosen as the starting point for identifying the concepts. Based on analyzing the B2B literature, a concept matrix was created, and the same concept matrix was then used as a framework for identifying concepts in the SOA literature. The concept matrix and the identified concepts are discussed in more detail in the next sections. III. C ONCEPTS IN THE B2B INTEGRATION STANDARDS APPROACH

A. Introduction articles that discussed both approaches or more general issues, were put into the third category. After the papers were categorized, papers were selected from both categories by prioritizing the quality of the source inside each category. The objective with this selection process was to analyze both approaches as equally as possible. From the literature search of the journals and conference proceedings a total of 51 articles were selected for further analysis based on the topic of each article. The papers were then categorized as described above, and based on this, 13 articles were included in this paper, namely [3], [6], [9]–[19]. Moreover, [8] suggest using forward and backward citation analysis of the selected articles, in order to find additional relevant sources. For this paper, three additional articles were included using this method, namely [4], [20], [21]. Finally, sections from two relevant textbooks were included in the literature review [2], [7]. A summary of the literature selection is presented in table III.

In the B2B integration standards approach to business automation, the goal is to enable automated business transactions across organizational boundaries [2]. The challenge is to keep business data consistent in an heterogeneous, autonomous and distributed environment [2]. In order to address these issues a number of B2B standards have been proposed [4]. The standards aim at answering the questions: ”what information needs to be shared between business partners, and when and how does the exchange happen?” [14]. An example of a B2B standard is the Electronic Data Interchange (EDI) standard [4]. However, with the evolution of XML as the ubiquitous data format, a number of XMLbased B2B standards, such as ebXML, RosettaNet and HL7, have been developed [4]. The focus in this paper is on the XML-based standards. Table IV presents the key concepts relating to the B2B integration standards approach. These concepts are further described in the next subsections.

C. Literature analysis

B. Key concept: heterogeneity

According to [8] a literature analysis should rather be a concept-centric synthesis of the literature, than an authorcentric summary of articles. To achieve this synthesis, the authors suggest the creation of a concept matrix while reading each article. The idea of the concept matrix is to first identify and collect concepts holistically from the chosen material, and then synthesize the findings by discussing each concept. The authors in [8] provide examples of how different concept matrices might look like, but they don’t go into further

One of the most important reasons why B2B integration standards are needed, is the heterogeneity of the IT environment between organizations [2]. Heterogeneity describes the degree of differences among the parties in the integration scenario [4]. Sources of heterogeneity are for example different enterprise applications, data structures, message semantics and structural differences in the business processes [2], [4]. 3 http://mindjet.com/products/mindmanager-8-mac/overview

TABLE IV B2B CONCEPT MATRIX . Source Heterogeneity [2] [4] [10] [13] [14] [15] [17]

x x

Concepts Layers of interoperability Communication Content Process x

x x

x x

x x

x x x

x x

x x x

The B2B standards aim to address the challenges with heterogeneity by providing pre-defined vocabularies and message exchange patterns between trading partners [10]. Thus, both parties know the order of the message exchanges prior to implementation, and more focus can be put on specifying the shared semantics of the business data. In essence, the standards aim to address the B2B integration challenges by ”bringing order into uncertainty by reducing variety” [14]. Different B2B integration standards address the heterogeneities from different perspectives [14]. A common approach is to use the concept of layering in order to provide relevant abstractions of the interoperability issues [2]. The concept of layering is discussed further in the next section. C. Key concept: layers of interoperability A layered approach is commonly utilized in the B2B integration standards approach [2]. Layering provides necessary separation of concerns and abstractions in order to address the different forms of heterogeneity in B2B environments [2]. When addressing the interoperability issues with B2B standards, three layers are commonly identified, namely: communication layer, content (or message) layer and process layer [4], [10], [14]. The B2B standards focus mostly on the content and process layers, while solutions for the communication layer has become more standardized [14]. Therefore, we focus here on the process and content layer issues. The process layer issues are addressed by specifying the order of message exchanges between the participants [14]. Enabling process level B2B integration is challenging because the partners need to understand each other’s processes semantically [4]. The B2B standards approach generally addresses this issue by specifying the interactions prior to design or implementation. On the content layer, the B2B standards aim at specifying business semantics of the data that is transferred [10]. Even though XML has become the lingua franca of e-business [10], there is still a need for semantic understanding of the data [15]. Plain XML provides syntactic interoperability, but it does not address semantic issues [14]. The business semantics are specified by the B2B standards, in the form of defining message structures and vocabularies for different business

situations [10]. For example, by specifying the valid structure of a purchase order message, the business parties can mutually agree upon the semantic meaning of a purchase order. To facilitate reuse, these semantic aspects are documented in, for example, dictionaries, ontologies and registries [17]. IV. C ONCEPTS IN THE SOA INTEGRATION APPROACH A. Introduction From a technological perspective, the SOA approach can generally be characterized as an evolutionary step in business automation, with roots in previous efforts such as modular programming, code reuse and object-oriented software development [6]. SOA, in its essence, is about assembling independent units of solution logic, called services, to form new IT systems [7]. The key enabler of the SOA approach is the development of open standards such as XML-based Web Services [6]. In an SOA, the goal is to enable largescale software reuse throughout the organization by having the SOA services available to any business process that needs them [20]. There is also an increased focus on building businessdriven and enterprise-wide IT systems in the SOA approach [7]. This is explicated, for example, in the SOA goals of supporting strategic business goals [7] and leveraging existing IT investments [20]. This means that SOA initiatives are often big organizational transformation projects [9]. In this paper, however, the focus is on integration issues related to SOA, and therefore the literature analysis focuses less on the strategic organizational aspects. In the following sections, key findings from the literature review are presented and discussed against the background of integration challenges in an SOA. Table V presents the key SOA concepts which are explained further in the next subsections. TABLE V SOA CONCEPT MATRIX . Source Heterogeneity [6] [7] [9] [11] [12] [16] [20] [21]

x x x x x x x

Concepts Layers of interoperability Communication Content Service x x x x x x x x x x x

x

x

Process x x

x x x

B. Key concept: heterogeneity Similarly to the B2B standards approach, heterogeneity is a central challenge in the SOA context. The main integration strategy in the SOA approach is to utilize as much as possible existing application functionality rather than building solutions from scratch [9], in order to leverage existing IT investments [20]. Therefore, addressing heterogeneity in the SOA context refers to enabling existing heterogeneous applications to interoperate while allowing them to continue to be independent.

As in the B2B standards approach, heterogeneities in the SOA context are addressed by utilizing different layers of abstraction. These layers of interoperability are discussed next. C. Key concept: layers of interoperability In an SOA, layering is used to separate concerns in order to reduce complexity [6] and to support different business value perspectives [20]. A layering model for SOA provides detailed descriptions of the elements and their relationships needed to build an SOA [20]. Comparing to the layers of interoperability in the B2B approach, similar layers can be identified in the SOA approach, namely communication, content and process layers. However, in the SOA approach an additional layer is identified between the process layer and the content layer called the service layer. The service layer is characterized by a focus on composing services to create new applications [6]. In [11] the authors provide a definition of composition based on philosophy and the field of systems thinking. The key issue is that composition is a form of abstraction. A composition is defined as ”a combination of two or more items yielding a new item, at a different level of abstraction” [11]. Furthermore, the characteristics of the new item, are defined by the items being combined and how they are combined [11]. This applies to the SOA context in the sense that service composition is realized in an SOA through runtime specific roles [7, p. 38]. This means that a SOA service provider may assume a service requester role at runtime in order to enable more complex service invocations and thus composed services. An SOA service that is designed with this kind of capability is referred to as a controller service [7, p.40] or a service aggregator [6]. In a service composition one controller service and at least two other services are integrated to provide the needed functionality [7, p. 40-41]. A consequence of the composite nature of the service layer is that the data flow in an SOA is not pre-defined as in the B2B standards approach. Rather, the data flow in an SOA depends on how the service compositions are designed, and, to some extent, on how the services in the composition interact during runtime. Moreover, the integration architecture of the service layer has a recursive nature, where individual services and composed services, can be further composed into increasingly complex structures. This is different from the B2B standards approach, where the process layer is implemented by the message exchange patterns that are pre-defined and which are not affected by design decisions relating to the integration solution. V. D ISCUSSION : THE CHARACTERISTICS OF SERVICE - ORIENTED B2B INTEGRATION

these characteristics we then characterize service-oriented B2B integration. B. Characteristics of the SOA and B2B standards integration approaches Based on the discussion in the previous sections, the B2B standards approach to integration is characterized as: • pre-defined invocation patterns with rich message structures and semantics As described above, the B2B standards focus more on the business semantics of the messages, while trying to bring order into the heterogeneities of B2B communication by standardizing the communication patterns, which constitute the business processes, pre-defined to implementation. Correspondingly, the SOA approach to integration is characterized as: • dynamic invocation patterns with simple message structures and minimal semantics The basis for this characterization is the focus in the SOA approach on service composition to enable dynamic and flexible business processes. There is less focus on defining rich business semantics of the actual messages. C. Characteristics of service-oriented B2B integration Combining the two characteristics specified above, we get a characterization of service-oriented B2B integration as: • enabling shared understanding of rich data in dynamic invocation patterns The implementation of this kind of service-oriented B2B integration, needs to be supported by both of the SOA and B2B standards approaches. We identify two initial issues that need to be addressed. First, we conclude that B2B communication is one SOA use case. However, the focus of integration in SOA is mainly from an intra-enterprise point of view, while B2B issues are not in the forefront. Therefore, by clearly identifying B2B communication as a distinct SOA use case, service-oriented B2B efforts could be more focused. This view is also echoed in [21]. Second, as the B2B standards approach focuses on semantic interoperability of business data, it could be used to support the definition of semantics for SOA messages and SOA service descriptions. While the SOA literature emphasizes the need for metadata descriptions of services and service requests, especially when moving towards inter-enterprise communication, the B2B standards could provide much needed formalism and structure to successfully implement these definitions.

A. Introduction

D. Reliability of the study

The research question for this paper was ”what characterizes service-oriented B2B integration?”. To answer this question we synthesize the findings from the previous sections first into characteristics of the SOA integration approach and characteristics of the B2B standards approach. Based on

Generally, it can be noted that both the literature search and the literature selection process were limited in scope. In order to enhance the reliability, the literature search could be extended to cover material prior to 2007. As one prominent source included in the study is from 2003 [4], this would

indicate that potentially relevant material has been left out in the literature search process. Correspondingly, the literature selection could also be extended to include material not covered in this paper. However, the reliability of the actual processes of the literature search, selection and analysis were addressed by explicating and motivating the decisions made. The literature search process was explicated with specifying which journals and conference proceedings were searched and why. Therefore, readers are able to assess the validity of the sources and the reasons against their own experiences. With regard to the literature selection, the selection criteria and the chosen papers were specified. Therefore, the reader should be able to repeat the search and selection process and then compare the selected material to the selected material in this study. The literature analysis was explicated and motivated through the use of mind maps and concept matrices. Again, the reader can utilize this information to assess the quality of the findings presented in this paper. VI. C ONCLUSIONS Business automation inherently involves integration issues due to the heterogeneous nature of organizations and IT systems. In this paper we outlined the notion of service-oriented B2B integration, which essentially involves the combined use of the SOA integration approach and the B2B standards integration approach. While the SOA approach focuses on flexible and dynamic support for business processes mainly within an enterprise, the B2B standards approach could be used for richer semantic descriptions of messages and SOA services, to bring the structure and order needed to be able to extend the SOA solutions into inter-enterprise contexts. Based on this study there is a need for further research into the service-oriented B2B integration approach. For example, more detailed descriptions are needed with relation to how the B2B standards actually could be utilized in the SOA context, especially related to the composite nature of the SOA service layer. For example, the pattern approach described in [16], or the eBusiness modeling approaches described in [18] could be potentially useful frameworks for exploring this issue further. For further research, we plan to extend the literature review in this paper by analyzing additional journals and conference proceedings, and by extending the coverage to publications prior to 2007. The goal is to bring more clarity in the notion of integration used in the context of SOA and B2B integration standards. Moreover, we plan to extend the analysis towards the organizational aspects of integration and interoperability in the SOA context. In this regard we plan to include the Enterprise Architecture and the interoperability frameworks approaches described in [17] into our future analysis.

ACKNOWLEDGMENT The authors would like to thank the SOLEA4 project for supporting this work. R EFERENCES [1] T. H. Davenport, “Putting the enterprise into the enterprise system.” Harvard Business Review, vol. 76, no. 4, pp. 121–131, 1998. [2] C. Bussler, B2B Integration: Concepts and Architecture. Springer, 2003. [3] T. Keller and T. Marko, “Management framework for business integration projects,” in 2009 IEEE Conference on Commerce and Enterprise Computing. IEEE, July 2009, pp. 226–232. [4] B. Medjahed, B. Benatallah, A. Bouguettaya, A. H. H. Ngu, and A. K. Elmagarmid, “Business-to-business interactions: issues and enabling technologies,” The VLDB Journal, vol. 12, no. 1, pp. 59–85, 2003. [5] G. Alonso, F. Casati, H. Kuno, and V. Machiraju, Web Services Concepts, Architectures and Applications, 1st ed. Springer, October 2003. [6] M. P. Papazoglou and W. J. Heuvel, “Service oriented architectures: approaches, technologies and research issues,” The VLDB Journal, vol. 16, no. 3, pp. 389–415, July 2007. [7] T. Erl, SOA Design Patterns, 1st ed. Prentice Hall PTR, January 2009. [8] J. Webster and R. T. Watson, “Analyzing the past to prepare for the future: Writing a literature review,” MIS Quarterly, vol. 26, no. 2, 2002. [9] N. Razinkov, N. Mashkif, D. Amid, and A. Fisher, “A holistic view of industry standards across soa solution stack,” in 2009 IEEE International Conference on Services Computing. IEEE, September 2009, pp. 144– 151. [10] F. Lampathaki, S. Mouzakitis, G. Gionis, Y. Charalabidis, and D. Askounis, “Business to business interoperability: A current review of XML data integration standards,” Computer Standards & Interfaces, vol. 31, no. 6, pp. 1045–1055, November 2009. [11] H. Kilov and I. Sack, “Mechanisms for communication between business and it experts,” Computer Standards & Interfaces, vol. 31, no. 1, pp. 98–109, January 2009. [12] A. Umar and A. Zordan, “Reengineering for service oriented architectures: A strategic decision model for integration versus migration,” Journal of Systems and Software, vol. 82, no. 3, pp. 448–462, March 2009. [13] T. Egyedi, “Standard-compliant, but incompatible?!” Computer Standards & Interfaces, vol. 29, no. 6, pp. 605–613, September 2007. [14] J. Nurmilaakso, P. Kotinurmi, and H. Laesvuori, “XML-based Ebusiness frameworks and standardization,” Computer Standards & Interfaces, vol. 28, no. 5, pp. 585–599, June 2006. [15] T. Vitvar, M. Moran, M. Zaremba, A. Haller, and P. Kotinurmi, “Semantic SOA to Promote Integration of Heterogeneous B2B Services,” in The 9th IEEE International Conference on E-Commerce Technology and The 4th IEEE International Conference on Enterprise Computing, E-Commerce and E-Services (CEC-EEE 2007). IEEE, July 2007, pp. 451–456. [16] L. Zhao, L. MacAulay, J. Adams, and P. Verschueren, “A pattern language for designing e-business architecture,” Journal of Systems and Software, vol. 81, no. 8, pp. 1272–1287, August 2008. [17] L. Guijarro, “Semantic interoperability in egovernment initiatives,” Computer Standards & Interfaces, vol. 31, no. 1, pp. 174–180, January 2009. [18] R. Schuster and T. Motal, “From e3-value to REA: Modeling multi-party eBusiness collaborations,” in 2009 IEEE Conference on Commerce and Enterprise Computing. IEEE, July 2009, pp. 202–208. [19] P. S. Tan, S. S. G. Lee, A. E. S. Goh, and E. W. Lee, “Context-enabled B2B collaborations,” in IEEE International Conference on Services Computing (SCC 2007). IEEE, July 2007, pp. 240–243. [20] A. Arsanjani, L.-J. Zhang, M. Ellis, A. Allam, and K. Channabasavaiah, “S3: A service-oriented reference architecture,” IT Professional, vol. 9, no. 3, pp. 10–17, 2007. [21] C. Bussler, “Service-oriented architecture: One size fits nobody,” in Enterprise Information Systems, J. Filipe, J. Cordeiro, and J. Cardoso, Eds. Springer Berlin Heidelberg, 2008, vol. 12, ch. 5, pp. 55–62.

4 http://www.uku.fi/solea/english.html