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Journal ArticleDOI

A theoretical investigation of the emerging standards for web services

01 Mar 2007-Information Systems Frontiers (Kluwer Academic Publishers-Plenum Publishers)-Vol. 9, Iss: 1, pp 119-134
TL;DR: This paper investigates the existing initiatives to identify commonalities that point to theories of ‘Language–Action’ as an appropriate theoretical basis for web services standards, and adapt work from these theories to develop a comprehensive reference framework for understanding web services Standards.
Abstract: Currently, standards for web services are being developed via three different initiatives (W3C, Semantic web services and ebXML). To the best of our knowledge, no theoretical perspectives underlie these standardization efforts. Without the benefit of a strong theoretical basis, the results, within and across these initiatives, have remained piecemeal. We suggest `Language---Action Theories' as a plausible perspective that can effectively define, assess and refine web services standards. In this paper, we first investigate the existing initiatives to identify commonalities that point to theories of `Language---Action' as an appropriate theoretical basis for web services standards. Next, we adapt work from these theories to develop a comprehensive reference framework for understanding web services standards. Finally, we use this reference framework to assess the three initiatives, and analyze the findings to provide insights for future development and refinement of web services standards.

Summary (5 min read)

1 Introduction

  • Standards are an important component for web services because they facilitate interactions among applications within and across organizations.
  • The resulting ‘standards stack’2 segregates the standards space into multiple layers which can provide boundaries for development and use of standards.
  • The authors review of prior work shows that holistic efforts to identify these layers have been lacking.
  • An appropriate theoretical framework is found in the stream of research known as Language-Action Perspective (LAP), which maps well to the core of service-oriented computing, i.e., ‘communication’ (Lemniotes, Papadopoulos, & Arbab, 2004).
  • The authors argue that this research stream can be adapted and applied to the web services standards space.

2 Web services as the realization of service-oriented computing

  • The service-oriented computing (SOC) paradigm3 is currently being realized through three different initiatives.
  • The first represents a major effort from the World-Wide Web Consortium (W3C), which builds on the premise that web services may be defined in a 3 Service-Oriented Computing (SOC) refers to a re-conceptualization of software to its essence, that of service (Papazoglou & Georgakopoulos, 2003; Turner, Budgen, & Brereton, 2003).
  • They declare their functional and nonfunctional requirements and capabilities in an agreed upon, machine-readable format (Curbera, Khalaf, Mukhi, Tai, & Weerawarana, 2003).
  • Programmatic manner so that companies can use them to integrate their operations (WS Arch, 2005).
  • The third represents an effort by the Organization for the Advancement of Structured Information Standards in conjunction with the UN as a way to build upon existing Electronic Document Interchange (EDI) infrastructure to facilitate global trade (ebXMLReq, 2001).

2.1 Alternative instantiations

  • The three initiatives conform to the same basic operations (publish, find and bind)4 and roles (service provider, service discovery agency, and service requestor) (Manes, 2003; Papazoglou & Georgakopoulos, 2003).
  • Each, however, operationalizes these with slight differences.
  • The authors explain and contrast the three with an online travel agent example: “[WSClient], a potential customer, queries a business registry for online travel agent.
  • The registry returns a list of online travel agent services.
  • [WSClient] selects [TAService] service, which is most fitting to its requirements and then binds to that service.”.

The W3C initiative

  • To realize their example scenario using the W3C initiative, [TAService] would create a Web Services Definition Language document (WSDL, 2001) to describe its service interfaces, and publish it in the Universal Description, Discovery, and Integration registry (UDDI, 2005).
  • [WSClient] would select a service which meets its requirements.
  • Assuming that [WSClient] selects [TAService], it would then bind its application to [TAService].
  • These three operations provide the basic building blocks of a service-oriented architecture (Curbera et al., 2003).
  • Simple Object Access Protocol (SOAP, 2003) messages conforming to [TAService]’s service declarations, and invoke [TAService].

The semantic web services initiative

  • The key difference between the W3C initiative and the semantic web services initiative is that the first depends on a syntactic description of web services, whereas the second utilizes more semantic descriptors derived from the OWL-based Web Services Ontology (Ankolekar et al., 2001).
  • To realize their example scenario using Semantic Web Services, [TAService] would create a service profile of its capabilities using the semantic descriptors.
  • The service profile contains a service model that describes how to interact with the service, and a service grounding that maps the information exchanges described in the service model into actual messages (Ankolekar et al., 2001; Paolucci, Sycara, Nishimura, & Srinivasan, 2003).
  • [WSClient] will query the Service Registry to find a required service, and when found, use its service grounding to bind the selected service.
  • Assuming that [WSClient] selects [TAService], both services can then generate messages to communicate.

The ebXML initiative

  • Unlike the first two, the ebXML initiative builds on existing EDI standards (ebXML, 2005) to specify the ebusiness XML language that globally distributed business partners can use to signify their compliance with minimum requirements for trading and conducting business (ebXML, 2005).
  • The example scenario is realized following the ebXML initiative in the following manner.
  • [TAService] would request the Business Process Specification Schema (BPSS) (ebBPSS, 2001) from an ebXML registry (ebRS, 2002) and populate it with its own capabilities that describe its implementation of an online travel agent service along with a Collaboration Protocol Profile (CPP) (ebXML-CPPA, 2002) that specifies the electronic interactions it can participate in.
  • When [WSClient]’s query returns [TAService] as a potential business partner, it can download [TAService]’s business profile from ebXML registry.
  • Both [TAService] and [WSClient] may then agree to conduct business (using their CPP), and will produce a Collaboration Protocol Agreement (CPA).

2.2 Commonalities across instantiations

  • The three initiatives are similar, yet different from one another in their vision because of the different challenges they see at the core of the web services paradigm.
  • Over the years, these three initiatives, which started as separate endeavors, have interacted with one another further emphasizing their commonalities5.
  • Communication, thus, represents ‘action-taking’ in the realm of web services and includes actions such as: (a) advertising available capabilities, (b) locating partners, (c) establishing commitment, (d) negotiating contract terms, (e) entering into a contract, (f) carrying out a transaction, (g) performing an exchange, (h) carrying out processes, (i) establishing trust, and (j) establishing relationships.
  • These activities closely correspond to business activities that increase in time span 5.
  • The UDDI standard, initially developed by OASIS (OASIS, 2005), is now part of the core W3C standards, and the ebXML standard advocated by OASIS (ebXML, 2005) is being integrated within the W3C efforts (WS Activity, 2005).

3 A theoretical framework for the web services standards space

  • The two arguments above, (a) communication as action, and (b) emphasis on business activities, lead us to suggest Language-Action Perspective (LAP) as an appropriate theoretical perspective for the web services standards space.
  • Following LAP, the authors can view information systems as actors, i.e., communicative social entities, with different roles, knowledge, and processes (Klein & Huynh, 2004), engaged in performing business activities A number of frameworks (e.g., SAMPO (Auramaki, Lehtinen, & Lyytinen, 1988) and DEMO (Dietz, 1994)) have been constructed on this foundation for modeling of business activities as communicative actions.
  • The choice of LAP as a theoretical perspective also meets the criteria for theory selection suggested by Holmstrom and Truex (Holmström & Truex, 2001): (a) selected theory’s historical context, (b) selected theory’s sensitivity towards details of the phenomenon under study, (c) selected theory’s impact on the choice of research method and (d) selected theory’s contribution to cumulative theory-building.
  • The final criterion assesses whether the selected theoretical perspective would contribute to cumulative theory-building in the target domain.
  • By suggesting this perspective, their selection directly contributes to theory-building in the target domain of web services standards.

3.1 A brief review of research on the language-action perspective

  • The use of Language-Action perspective (LAP) for information systems can be traced to Flores and Ludlow (Flores & Ludlow, 1980), who argued that human beings are linguistic beings and act through language (Schoop, 2001).
  • LAP formulates a norm-based and interpretive alternative of how language is constituted in social life to analyze its implications for the design of information systems (Auramaki et al., 1988; Goldkuhl & Lyytinen, 1982, 1984; Hirschheim, Klein, & Lyytinen, 1995; Lyytinen, 2004).
  • It is, therefore, not so much centered on perfecting computational models and techniques.
  • An action view on language and communication for the analysis of business activities is, thus, the essence of LAP.

3.2 An LAP-inspired framework for the web services standards space

  • Developing an LAP-inspired framework for the web services standards space requires one key adaptation of the premises underlying LAP.
  • The participants in the communicative action represent computationally described web services instead of organizational actors (Aakhus, 2004).
  • As established in the previous section, the objective remains carrying out specific business activities.
  • The framework the authors propose, accordingly, consists of three levels: (a) communication platform, (b) communicative act, and (c) rational discourse.

Communication platform

  • The first level is the enabler of communicative acts between communicating parties.
  • There must be common semantics, so that messages are correctly interpreted by the parties.
  • The above conditions suggest that a prerequisite to successful communicative acts is a communication platform.
  • It can be divided into three layers: [channel], [messaging] and [guarantee].
  • The second and third conditions establish the need for common syntax and semantics for messages.

Communicative act

  • The participants achieve this goal through four phases (Goldkuhl, 1996, 1998): First, the participant who has ability (capacity and know-how) to perform an action offers and exposes it in a form searchable by other participants.
  • Second, a participant who needs certain performance of an action, searches for partners who offer this ability.
  • Third, after the participants find each other, they establish contact, exchange proposals and negotiate with each other to reach an agreement (Schoop, 2002).
  • The four phases directly map to four layers: [capability exposure], [capability search], [proposal and negotiation] and [contract establishment].

Rational discourse

  • This coordination via rational discourse can include four layers: First, interaction between actors consist of patterns of triggers and responses (Dietz, 2002; Lind & Goldkuhl, 2001), i.e., conversations among actors are made up of a finite sequence of communicative acts (Dietz, 2002; Weigand et al., 1998).
  • This includes the need to regulate long term contracts, and the ability to change business transactions as the contracts changes (Goldkuhl & Melin, 2001), i.e., it requires a global overview of running contracts and explicit control of the running transactions and existing relationships (Weigand et al., 1998).
  • These map to the four layers: [exchange], [transaction], [relationship management] and [managing concurrent contracts] respectively.

4.1 Assessment of the W3C initiative

  • Table 2 summarizes the results of assessing the W3C initiative (WS Arch, 2005) against the LAP-inspired reference framework.
  • This layer, thus, corresponds to the [messaging] layer in the LAP-inspired framework.
  • The description layer provides a functional description of a service in terms of its interface and implementation (Turner et al., 2003); (Kreger, 2003).
  • Layers from the LAP-inspired framework with no corresponding efforts in the W3C initiative, therefore, include [proposal and negotiation], and [contract establishment].

4.2 Assessment of the semantic web services initiative

  • The semantic web services initiative provides a framework based on a set of roles and requirements for machine-readable semantic descriptions for deployment of web services (SWS Arch, 2005).
  • The communication platform layers demonstrate the clearest mapping between the LAP- inspired framework and the semantic web services initiative because they utilize the foundation provided by the W3C initiative, enhancing it with the Ontology Web Language (OWL, 2004).
  • The next layer, service contract negotiation, provides a protocol that service providers and clients can use to negotiate and establish contracts (SWS Arch, 2005).
  • The standard that crosses all these layers is SWSL-Rules (SWSL, 2005).
  • The status monitoring and termination and compensation sublayers also contain elements that correspond to the [managing concurrent contracts] layer in the LAP-inspired framework.

4.3 Assessment of the ebXML initiative

  • The ebXML initiative combines components from divergent XML initiatives to develop a single business standard (ebXML-Req, 2001) that can operate on existing EDI implementations (ebXML-TA, 2001).
  • First, the collaboration protocol profile layer describes partner capabilities and service interface requirements (ebXML-TA, 2001).
  • One layer from the LAP-inspired framework with no corresponding effort in the ebXML initiative, therefore, is [proposal and negotiation].
  • This layer corresponds to the [exchange] layer in the LAP-inspired framework.

5 Discussion

  • The assessment of the three web services initiatives reported in the previous section suggests several recurring themes.
  • The W3C and ebXML initiatives indicate no standards for this layer, proposed or recommended.
  • All three initiatives contain standards that provide partial support for the [transaction] layer.
  • Useful research in this direction is available elsewhere (Goldkuhl & Melin, 2001; Goldkuhl & Röstlinger, 1999).
  • The standards proposed by the W3C and semantic web services initiatives manage only a single contract or transactions related to that single contract, i.e., they do not provide a global overview of multiple contracts and their related multiple transactions as suggested by the LAP-inspired framework.

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A Theoretical Investigation of the
Emerging Standards for Web Services
Karthikeyan Umapathy and Sandeep Purao
College of Information Sciences and Technology,
Penn State University
University Park, PA 16802
{kumapathy, spurao}@ist.psu.edu
Keywords:
Service-Oriented Computing, Web Services, Web Services Standards, W3C web services, Semantic Web
Services, ebXML, Standards Stacks, Layered Models, Language-Action Perspective, Reference
Framework
© 2006. K. Umapathy, S. Purao.
You can find the original print version in below link
DOI: http://www.springerlink.com/content/r282201465372g67/

A Theoretical Investigation of the
Emerging Standards for Web Services
*
Abstract
Currently, standards for web services are being developed via three different initiatives
(W3C, Semantic web services and ebXML). To the best of our knowledge, no theoretical
perspectives underlie these standardization efforts. Without the benefit of a strong theoretical
basis, the results, within and across these initiatives, have remained piecemeal. We suggest
‘Language-Action Theories’ as a plausible perspective that can effectively define, assess and
refine web services standards. In this paper, we first investigate the existing initiatives to identify
commonalities that point to theories of ‘Language-Action’ as an appropriate theoretical basis for
web services standards. Next, we adapt work from these theories to develop a comprehensive
reference framework for understanding web services standards. Finally, we use this reference
framework to assess the three initiatives, and analyze the findings to provide insights for future
development and refinement of web services standards.
Keywords:
Service-Oriented Computing, Web Services, Web Services Standards, W3C web services, Semantic Web
Services, ebXML, Standards Stacks, Layered Models, Language-Action Perspective, Reference
Framework
*
The authors would like to thank editors for this special issue and two anonymous reviewers for helpful comments
on an earlier draft of this paper, and M. Hopkins for several editorial suggestions.

1
1 Introduction
Standards are an important component for web services because they facilitate
interactions among applications within and across organizations. They must, therefore, cover a
wide array of concerns such as messaging, publishing, discovering, and composing. Constructing
a single, monolithic standard that encompasses all these is enormously difficult. Ongoing work
on web services standards
1
has, therefore, developed separate core standards for publishing
(WSDL (WSDL, 2001)), finding (UDDI (UDDI, 2005)), and binding (SOAP (SOAP, 2003)).
Such ‘separation of concerns’ is a necessary attribute of web services standards, which can be
achieved by segmenting the standards-space into different ‘layers’ (similar to (Kreger, 2001)).
The resulting ‘standards stack’
2
segregates the standards space into multiple layers which can
provide boundaries for development and use of standards. An analogy can be seen in the OSI
seven-layer model (OSI, 1994), which separates networking technologies into a seven-layer
abstraction. A standards stack for web services can perform a similar function.
An important concern, however, is the identification of appropriate layers in this stack.
Without an agreement about these layers, development of standards in this space remains a
piecemeal effort. For example, standards that cross layers, such as WS-BPEL (WS-BPEL, 2005)
and WS-CDL (WS-CDL, 2004), have been proposed over the last few years. Competing
standards within a layer have also been proposed, such as WS-coordination (WS-CF, 2004) and
WS-CDL (WS-CDL, 2004), causing confusion for information systems developers.
Our review of prior work shows that holistic efforts to identify these layers have been
lacking. Prior work has either produced compilations of existing standards (Mukhi, Plebani,
1
Appendix A shows a list of standards proposed for web services following different initiatives.
2
The term ‘web services stack’ refers to a ‘stack of web service standards’ (Sleeper & Robins, 2001).

2
SilvaLepe, & Mikalsen, 2004) or has been driven by considerations of adoption of standards
(Gosain, 2003). Without the benefit of a holistic framework guided by appropriate theories, work
in this space has suffered from false starts (WS Arch, 2005; WSCI, 2002).
An appropriate theoretical framework is found in the stream of research known as
Language-Action Perspective (LAP), which maps well to the core of service-oriented computing,
i.e., ‘communication’ (Lemniotes, Papadopoulos, & Arbab, 2004). LAP was originally
developed in the context of human actors communicating with one another to achieve
organizational goals (Lyytinen, 2004). We argue that this research stream can be adapted and
applied to the web services standards space. Our objective in this paper is to adapt research from
the Language-Action perspective to construct a reference framework for the web services
standards space, and demonstrate how it can be used to assess existing standards or develop
new standards. The paper starts by investigating how the three existing initiatives operationalize
core web services concepts. Next, by adapting important concepts from LAP, we develop a
reference framework for the web services standards space. We then demonstrate how the
reference framework can be used to assess the existing initiatives. Finally, we discuss
implications for refinement and development of future standards.
2 Web services as the realization of service-oriented computing
The service-oriented computing (SOC) paradigm
3
is currently being realized through
three different initiatives. The first represents a major effort from the World-Wide Web
Consortium (W3C), which builds on the premise that web services may be defined in a
3
Service-Oriented Computing (SOC) refers to a re-conceptualization of software to its essence, that of service
(Papazoglou & Georgakopoulos, 2003; Turner, Budgen, & Brereton, 2003). In an SOC environment, applications
are recast as “services.” They declare their functional and nonfunctional requirements and capabilities in an agreed
upon, machine-readable format (Curbera, Khalaf, Mukhi, Tai, & Weerawarana, 2003).

3
programmatic manner so that companies can use them to integrate their operations (WS Arch,
2005). The second represents an effort that is backed by the research community interested in a
vision of the Semantic Web that augments web services with semantic components (Paolucci &
Sycara, 2004). The third represents an effort by the Organization for the Advancement of
Structured Information Standards (OASIS) in conjunction with the UN as a way to build upon
existing Electronic Document Interchange (EDI) infrastructure to facilitate global trade (ebXML-
Req, 2001).
2.1 Alternative instantiations
The three initiatives conform to the same basic operations (publish, find and bind)
4
and
roles (service provider, service discovery agency, and service requestor) (Manes, 2003;
Papazoglou & Georgakopoulos, 2003). Each, however, operationalizes these with slight
differences. We explain and contrast the three with an online travel agent example:
“[WSClient], a potential customer, queries a business registry for online travel agent. The
registry returns a list of online travel agent services. [WSClient] selects [TAService]
service, which is most fitting to its requirements and then binds to that service.”
The W3C initiative
To realize our example scenario using the W3C initiative, [TAService] would create a
Web Services Definition Language document (WSDL, 2001) to describe its service interfaces,
and publish it in the Universal Description, Discovery, and Integration registry (UDDI, 2005).
[WSClient] will query the registry for services, which provide online travel agent capabilities.
[WSClient] would select a service which meets its requirements. Assuming that [WSClient]
selects [TAService], it would then bind its application to [TAService]. [WSClient] will generate
4
A native capability of SOC applications is the ability to describe themselves (publish), locate service partners
(find), and invoke these services as required (bind). These three operations provide the basic building blocks of a
service-oriented architecture (Curbera et al., 2003).

Citations
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7,241 citations

Book ChapterDOI
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TL;DR: This chapter introduces web services and explains their role in Microsoft’s vision of the programmable web and removes some of the confusion surrounding technical terms like WSDL, SOAP, and UDDI.
Abstract: Microsoft has promoted ASP.NET’s new web services more than almost any other part of the.NET Framework. But despite their efforts, confusion is still widespread about what a web service is and, more importantly, what it’s meant to accomplish. This chapter introduces web services and explains their role in Microsoft’s vision of the programmable web. Along the way, you’ll learn about the open standards plumbing that allows web services to work and removes some of the confusion surrounding technical terms like WSDL (Web Service Description Language), SOAP, and UDDI (universal description, discovery, and integration).

546 citations

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TL;DR: Three interrelated frameworks are presented as a first attempt to define the fundamentals of service systems, which can be applied together to describe, analyze, and study how service systems are created, how they operate, and how they evolve through a combination of planned and unplanned change.
Abstract: Service systems produce all services of significance and scope, yet the concept of a service system is not well articulated in the service literature. This paper presents three interrelated frameworks as a first attempt to define the fundamentals of service systems. These frameworks identify basic building blocks and organize important attributes and change processes that apply across all service systems. Although relevant regardless of whether a service system uses information technology, the frameworks are also potentially useful in visualizing the realities of moving toward automated service architectures. This paper uses two examples, one largely manual and one highly automated, to illustrate the potential usefulness of the three frameworks, which can be applied together to describe, analyze, and study how service systems are created, how they operate, and how they evolve through a combination of planned and unplanned change.

355 citations

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TL;DR: An overview of emerging research concepts in services computing without attempting to unify them is provided, and it is taken that the ultimate goal of services computing is to create the necessary technological and managerial foundation to support enterprise agility.
Abstract: The advancement of web services in the last few years has spurred a number of revolutionary concepts in information technology and management including service-oriented architectures, service-oriented computing, and services science, management and engineering, which can be collectively called as "services computing." Services computing is a new research field that goes beyond traditional computing disciplines as it includes not only architectural, programming, deployment, and other engineering issues, but also management issues such as business component modeling, business process design, and service delivery. In this paper, we provide an overview of emerging research concepts in services computing without attempting to unify them as it will take sometime for the field to become mature. In addition, we take a position that the ultimate goal of services computing is to create the necessary technological and managerial foundation to support enterprise agility. In this short paper, we give an overview of services computing, describe its relationship to enterprise agility, and discuss basic technical and managerial issues. Finally, we introduce the papers that are published in this special issue.

116 citations


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