A FRAMEWORK FOR ENGINEERING ENTERPRISE AGILITY Abd Rahman Mokhtar Martin Hanneghan Madjid Merabti School of Computing and Mathematical Sciences Liverpool John Moores University United KingdomABSTRACT able to remain or be competitive and will fall by the wayside (Merabti et al, 1999). It is theCentral to engineering enterprise agility is the enterprise’s information systems that provide itability to meaningfully share and communicate with its institutional memory and its “nervousinformation between enterprise systems. Such a system” (Gates, 1999), (Ryan, 1997). If, as thecharacteristic enables the agile enterprise to enterprise grows and adapts, its informationpossess the capabilities and processes to allow systems cannot adapt with it, the growth of thethe enterprise to respond to and master change, entire organisation is impeded.and hence achieving and maintainingcompetitiveness. In this paper, we present a Many key technologies have emerged thatnovel framework for engineering enterprise promote the development and implementation ofagility. The framework encompasses the idea of more effective and adaptable information systems.ontology viewpoint, i.e. a viewpoint that is These provide the context for enterprisecommitted to “an explicit specification of a development and contribute to enhancing theconceptualisation”. The framework also involves agility of the enterprise, a crucial capability tothe provision of an appropriate middleware and enable enterprises to respond and master changemultiagent environment in supporting the and hence achieving and maintainingexecution of distributed processes and their competitiveness.automation. The paper presents our proposed One of the most significant key technologies ispreliminary architecture and its components. The the development of intelligent desktop clientformer utilises the ubiquitous HTTP protocol of workstations and networking infrastructures suchthe World Wide Web, in enabling accessibility as the Internet and the World Wide Web. Thisand connectivity of the architectural components has put more processing power in the hands of thevia a middleware environment. The integration end-users as well as enabling distributedof ontology, viewpoints, and agent-middleware processing among multiple computing resources.based environment is pursued by utilising open The development and growth of these enterprisestandards in programmatic and metalanguage systems are, however, characterised by complexsupport, thereby enhancing component and chaotic manifestation of platforms, languagesinteractivity and connectivity. The framework, and proprietary environments. The network andthus, promotes semantic interoperability and protocols underlying and connecting thesecoherence and the subsequent growth and agility systems might be just as diverse. Thisof heterogeneous and distributed enterprise heterogeneity that is prevalent in an enterprise’ssystems. information systems is due to factors such as engineering trade-offs, which arise from theKEYWORDS absence of an acceptable solution to a complexEnterprise, agility, ontology, viewpoints, agents, engineering problem; accumulation of legacymiddleware. systems over time; and varying system costs (Vinoski, 1997).1. INTRODUCTION As an enterprise employs the availableIn an era of intense global competition, information systems resources for a wide range ofenterprises that more effectively meet a client’s activities that include distributed databaseneed using fewer resources than their competitors transactions and information interchange, the needwill thrive, while those who cannot, will not be for software agents in the automation of the tasks
involved is much desired. These software agents refined (Guarino, 1998), as a logical theorymay play autonomous roles within a middleware accounting for the intended meaning of a formalenvironment (Bernstein, 1996) – an environment vocabulary (not necessarily) as part of a logicalthat provides a middle platform that holds language. The ontology of an enterprise,together the various elements or components of constructed through the processes ofdistributed and heterogeneous enterprise systems. conceptualisation and explication of theWithin such environments, the software agents conceptualisation, will therefore present itself as amay be implemented to enable automation of, for framework for modelling of and sharedexample, data translation and transformation; understanding between, the various aspects of thebrokering between users, other software agents enterprise.and information resources; validation or Furthermore, the construction of a complexmaintenance within and between resources; as description or model associated with an enterprisewell as presentation of information to users. or system involves many stakeholders orThe communication between systems in a participants and these participants would havedistributed and heterogeneous environment different views of the system they are trying torequires the unhindered ability to meaningfully describe or model within the domain of discourse.share information. However, in large and The combination of the participant and the viewcomplex systems, such ability is suppressed since that the participant holds is said to be a viewpointthe meaning of information can be drastically (Sommerville, 1995).affected by the context in which it is viewed and An enterprise information model is logicallyinterpreted. The development of an ontology of composed of a number of discrete componentsdomain concepts and terms, along with their which, when synthesised, produce the wholerespective formal and unambiguous definitions, model. For example, in manufacturing, thepotentially provides the basis to meaningfully accommodation of needs of various departmentsshare information. An ontology is defined as “an such as designs, materials, suppliers, stockexplicit specification of a conceptualisation” control, finance, logistics, etc. is necessary to(Gruber, 1995). The “conceptualisation” involved support its business objectives. As the enterpriseis an abstract, simplified worldview (i.e. the information requirements change or evolve, newglobal set of concepts, their definitions and inter- viewpoints arise, each being uniquelyrelationships), that represents the domain of characterised by the combinatory state of thediscourse. The definition of an ontology is further participant and the view, as depicted in Figure 1.P a r tic ip a n t A M a n u fa c t u r in g E n t e r p r is e M a t e r ia ls V ie w S u p p lie r s D e s ig n( A ) A v ie w p o in t is a c o m b in a t io n o f t h e p a r tic ip a n t a n d t h e v ie w t h a t t h e p a r t ic ip a n t h o ld s .( B ) T h r e e d if fe r e n t v ie w p o in t s t a te s , in s t a n tia t e d a s a fu n c tio n o f t h e p a r tic ip a n t a n d v ie w .F ig u re 1 . D iff e re n t e n te rp r is e v ie w p o in ts
The application of viewpoint analysis during, for oriented hierarchies, as well as allowingexample, the early stages of elicitation or consuming applications to check data forextraction of enterprise system requirements is structural validity during processing. Theseone area of system development where many capabilities enable the prospect of data ordiverse client views are prevalent (Hanneghan et knowledge interchange in expressing, foral., 2000). example, an enterprise content model and its semantics. Furthermore, horizontal-enterpriseOntologies can be used as a means to capture applications, such as software distribution,precisely information that needs to be delivered searching/filtering, and e-commerce, in additionfrom one system to another. It is the precise and to vertical-enterprise applications, such as health-unambiguous specification of ontologies that can care, manufacturing, and education, can utilise theenable systems to interoperate effectively and XML standard in attempting to achieveefficiently. However, herein lies the problem: sustainable global interoperability (Smith andontologies that completely capture the essence of Poulter, 1999) e.g. the implementation ofan enterprise are almost impossible to describe. business-specific tasks across domains. MajorThe number of unique facets of an enterprise is Information Technology solution providers suchjust too great to enumerate and the subtleties in as Microsoft and Hewlett Packard are developinginterpretation of each facet give rise to frameworks for e-commerce using the power ofambiguities that render the ontology unusable in XML (e.g. BizTalk from Microsoft and ESpeakall but the simplest situations. In our research, from Hewlett Packard).viewpoints are utilised to aid the construction ofan ontology, as it provides an initial context or Middleware architectures are increasingly used instarting point for the identification of key the network-centric, Internet-savvy environmentconcepts and relationships in the domain of in an attempt to host robust business logic,interest. balance distribution of processing, provide complex and rapid data access, manage persistent2. BACKGROUND state and session, and provide guaranteed and reliable processing. Middleware is typicallyMost documents on the World Wide Web are divided into five basic categories: transactionconstructed using markup language representation processing middleware, which provides(Bosak, 1997) that is based on an open standard distributed transaction monitoring, management,namely Standard Generalised Markup Language, load balancing, and fail-over across multiple dataSGML (ISO 8879) (Goldfarb, 1997). The current sources; message-oriented middleware (MOM),widely used markup language (namely Hypertext which provides asynchronous communicationsMarkup Language, HTML) is a simple SGML and guaranteed delivery of messages or eventslanguage variant that is well suited for small and between applications across the network; objectreasonably simple documents. However, as web request brokers (ORBs), which providedocuments have become larger and more communication pipelines among softwarecomplex, web content providers have begun to components that make up a distributed system;experience the limitations of a medium that does data access middleware (Hanneghan et al., 1998),not provide the extensibility, structure, and which provides efficient and rapid access tovalidation needed for large-scale distributed heterogeneous data sources; and applicationinformation processing (Hanneghan et al., 1996). servers, which provide extensible platforms forRecent efforts to introduce new standards such as assembling, deploying, and managing distributedResource Definition Format (RDF) (Lassila et al., applications, connecting software components1999) have yet to achieve widespread acceptance. with heterogeneous databases and networkThe next generation markup language variant resources. CORBA (the Common Object Request(namely Extensible Markup Language, XML) Broker Architecture) (Maffeis and Schmidt,(Bray et al., 1998), (Mace et al., 1998) addresses 1997), (Siegel, 1998) and the Java Remotethe issues described above. Its extensibility Method Invocation (RMI) programming modelenables users to specify their own tags or (Singhal and Nguyen, 1998), (Waters, 1998) areattributes in order to parameterise or semantically representative of object request broker andqualify the information to be processed. There is application servers middleware, respectively.support for specification of the deep structures Furthermore, the development and deployment ofneeded to represent database schemas or object- middleware environment can be pursued as
component-based, whereby the building of identification of key concepts and relationships insoftware systems is carried out using pre- the domain of interest; production of precisepackaged generic elements (Meyer and Mingins, unambiguous text definitions for such concepts1999). These elements or components when and relationships; identification of terms to referwritten in Java to the Enterprise Java specification to such concepts and relationships; and finally(are known as Enterprise JavaBeans) have the agreeing on all of the above. In order to aid theability to communicate using Java RMI or utilisation of the ontology, the explicitCORBA Internet Inter-ORB Protocol (IIOP), and representation of the conceptualisation will needutilise Enterprise Java services. McFall (1998) to be expressed in some formal language.discusses the interplay between Java-enabled Web Blàzquez et al. (1998), describes theclients, CORBA, Web servers, and backend METHONTOLOGY framework, a frameworksystems (such as application and transaction that enables the construction of ontologies at thesystems) as part of a model that assumes universal knowledge level and includes: the identificationconnectivity, distributed environment, and cross- of the ontology development process, a life cycleplatform interoperation. based on evolving prototypes, a method forThe use of software agents, as individually specifying ontologies at the knowledge level andautonomous software entities to hide the multilingual translators that automaticallydistribution and complexity problems is described transform the specification into several targetby Laufmann (1997) with the focus especially on codes.the practical issues that are commonly faced in The use of an ontology in the context of andistributed and heterogeneous enterprise enterprise is further discussed by Uschold et al.environments. Additionally, effective (1997), whereby a glossary of terms pertinent tocommunication of knowledge between agents in an enterprise, are expressed in a restricted anddistributed and heterogeneous enterprise structured form of natural language supplementedenvironment needs to be based on a common with a few formal axioms. The ontologyunderstanding of terms contained in the messages described has five top-level classes for integratingpassed between agents in the environment. Jones the various aspects of an enterprise, consisting of(1998) discusses the construction of a shared metaontology; activities and processes;ontology, as one of the main stages in the organisation; strategy; and marketing.development of a multiagent system. Jain et al.(1999) expands the multiagent metaphor further in The range of ontology-based work pertaining todescribing the multiagent system as a sphere of enterprise modelling is reviewed by Fox andcommitment which encapsulates the promises and Gruninger (1998), who introduce the concept of aobligations the agents may have toward each generic enterprise model (GEM) and extend thatother. By employing flexible commitments, their to the concept of a deductive enterprise modelapproach allows the commitments to be (DEM). The former model essentially describesmanipulated in various ways. Thus, for example, an object library that defines the classes of objectsbesides the ability to create and discharge that are generic across a type of enterprise, suchcommitments, agents are allowed, although as manufacturing (Schlenoff et al., 1998), and cancannot be wantonly performed, to cancel be used or instantiated in defining a specificcommitments. Such flexibility can furthermore enterprise pertaining to the latter model.be empowered to mobile agents. These agents The analysis of an enterprise displaying athat are created in one execution environment, can complex structure and with many interlockingtransport their states and codes, as discussed by constraints on their construction and behaviour,Wong et al. (1999), to another execution necessitates, for example, multiple viewpoints forenvironment where they can resume tasks. The complexity control and separation of concerns.migration of state and codes of the agents can, for The use of a viewpoint method at theexample, be facilitated by an open middleware requirements stage of systems development isenvironment. exemplified in the work of Kotonya andUschold and Gruninger (1996) provides a general Sommerville (1996). Their service orientedintroduction to the design and use of ontologies viewpoint method takes into account both theand outlines both informal and formal end-user and organisational considerations, inmethodology for developing and evaluating them. generating system requirements. Sommerville etThe process of building an ontology involves al. (1998) further discusses a practical and flexible
approach in eliciting and validating system that possesses the capabilities and processes thatrequirements, by introducing the notion of allow the enterprise to respond and master changeconcerns as global high-level criteria that are used - an enterprise that has the ability to continuouslyas drivers of the requirements elicitation process. monitor market demands; quickly respond byThe conceptual relationship between concerns and providing new products, services and information;viewpoints as a sociotechnical pyramid is quickly introduce new technologies; and quicklydepicted in Figure 2. These concerns, potentially, modify business methods (Nagel and Dove,affect every aspect of the system. 1991). S a fe ty c o n c e rn C o m p a t ib ilit y c o n c e r n A t t h e a p e x o f th e p y r a m id E q u ip m e n t a r e th e v ie w p o in t s w h ic h in t e r a c t v ie w p o in t d ir e c t ly w it h t h e s y s t e m . A t it s b a s e a r e th o s e v ie w p o in t s w h ic h O p e r a to rs h a v e t h e m o s t in d ir e c t a s s o c ia tio n v ie w p o in t w it h th e s y s te m , b u t n e v e r t h e le s s h a v e a s ta k e in it . S u p e r v is o r s v ie w p o in t O r g a n is a t io n v ie w p o in t S o c io - p o lit ic a l e n v ir o n m e n t v ie w p o in t F ig u r e 2 . R e la tio n s h ip b e tw e e n c o n c e r n s a n d v ie w p o in ts a s a s o c io te c h n ic a l p y r a m idMannion et al. (1998) describes the use of 3. CURRENT WORKviewpoints to define domain requirements that With the proliferation of distributed andtake into consideration the reusability of the heterogeneous computing facilities andrequirements against the background of overlap of infrastructures, an enterprise’s informationdomain requirements due to the presence of systems are continuously depended upon to bringmultiple systems and multiple users. The authors’ about constructive changes in many domainsVORD (viewpoint-oriented domain requirements (King and Tester, 1999). The growingdefinition) method consists of four steps: scope complexity of enterprise information and thethe domain, characterise the domain, document increasing necessity to communicate andthe viewpoints, and analyse the viewpoints. The exchange this information, however, hinges on theoutputs from this method serve as inputs to the requirement for an unhindered ability torest of the domain engineering process. meaningfully share information. As a first stepFrom an operations perspective, the aspects of towards addressing the current lack of suchdomain modelling and process engineering must semantic interoperability across multiplebe able to supply information and knowledge platforms and processing environments, ournecessary to support the tasks and operations of research develops a framework based on thethe enterprise. These would need to be notion of “ontology-driven information systems”streamlined and integrated to enable the enterprise (Guarino, 1998). This provides a context forto be agile and hence remains competitive, that is, enterprise systems to be integrated across theirthe ability to produce products and services that functions, and hence the framework forare of consistently high quality throughout the engineering enterprise agility.product/services life, customised to market needs, The scope and scenario of our research activitiesopen in that they may be integrated with other is depicted in Figure 3. The research stressed theproduct/services, environmentally benign, and importance of the use of ontology in antechnically advanced. An agile enterprise is one
D is t r ib u t e d & H e t e r o g e n e o u s E n te r p r is e S y s t e m s A n e n t e r p r is e , a s w e ll a s o th e r s y s t e m s s u c h a s X a n d Y in d ic a te d h e r e , a r e g e n e r ic r e p r e s e n t a t io n o f t h e c o m p o n e n ts o f th e d is tr ib u t e d a n d V ie w p o in t h e t e r o g e n e o u s e n v ir o n m e n t . M o d e llin g S y s te m M u lt ia g e n t S y s t e m a n d A n a ly s is X P a rti- c ip a n t C a p t u r in g v ia S y s te m M a r k u p L a n g u a g e V a ria n t Y W o r ld V ie w M id d le w a r e V ie w V ie w V ie w A D G V ie w V ie w V ie w V ie w V ie w V ie w B C E F H I O n to lo g y α O n to lo g y β O n to lo g y γ O n to lo g ic a l R e p r e s e n ta tio n A n E n te r p r is eF ig u re 3 . R e s e a rc h s c o p e a n d s c e n a r iointerdisciplinary and integrated setting, i.e. in with the system by sending and receivingconjunction with the utilisation and development messages. The stimulus obtained from anof concepts derived from a range of contemporary incoming message is represented by a use caseareas of interest, such as: open metalanguage scenario which expresses a specific functionalitysupport for information exchange, viewpoint- of the system.oriented modelling and analysis, middleware The exposure of system functionalities throughenvironment, and multiagent paradigm. use cases can thus provide a mechanism for viewpoints to be constructed. The set of human 3.1 Ontological Representation readable description of terms, concepts, andOur research investigates the ontological relations within the viewpoints relates or maps torepresentation of a distributed and heterogeneous a number of aspects of ontology development,enterprise. The ontology, as part of a world view, such as type, subject, and purpose of ontology;provides the basis to model the enterprise and scope in relation to notions that includes numbermeaningfully share information between the of concepts representing classes, number ofvarious facets of the enterprise. Of equal interest concepts representing instances, number ofat this research stage is the investigation of the explicit axioms, number of class concepts perexplicit relationship between ontological hierarchy level, etc. Thus the outcome of thisstructures of an enterprise and the generation of initial stage is the ontological representation ofviewpoints. For a given viewpoint state, the the distributed and heterogeneous enterpriseparticipant is regarded as an actor or class type pertaining to its structure, activities, processes,rather than an instance, the participating entity as information, resources, people, behaviours, goals,well as being an external entity to the system, and organisational constraints. It provides arepresents a role or a number of roles in the vocabulary of terms and relations with which aenterprise or system. The actor communicates domain can be modelled.
Additionally, our utilisation of a visual modelling important measure in evaluating the process oflanguage such as the Object Management Groups integrating disparate enterprise systems.(OMG) Unified Modelling Language (UML)facilitates the domain modelling process. UML 3.2 Capturing via Markup Languageprovides a visual expression of domain models, in Variantterms of object-oriented diagrams that are:accurately descriptive of the system to be built; The ontology can be parameterised using an openconsistent in avoiding conflicts between domain metalanguage for markup with support forviews e.g. the use case view and concurrency extensibility, structure and validation. Theview (the view that relates to the non-functional development of a markup language variant inproperty of the system); and convenient to representing the captured ontology in expressingcommunicate to users and be amenable to change an enterprise model provides a framework for(Eriksson and Penker, 1998). semantic interoperability in enabling data or knowledge interchange over a networkFurthermore the use of UML in representing infrastructure such as the World Wide Web.enterprise conceptualisation provides adiagrammatic expression of the ontology (e.g. in We utilise XML as the deployment standards interms of class diagrams) which then facilitates the markup language based capturing process.the process of modelling and identifying The listing below (Listing 1) exemplifies the usemismatches between ontologies, and the of XML in capturing some ontologicalassessment of enterprise heterogeneity (Visser et representation of a Marketing Department of anal., 1998). Enterprise. In essence the XML-based deployment allow user-defined markup elementsThe level of enterprise heterogeneity and ontology to qualify data and its structure, in expressing amismatches and their contextual trade off with the particular knowledge domain.need for interoperability, for example, provides an < ? x m l V e rs io n = " 1 .0 " ? > < ! D O C T Y P E e n t e r p r is e [ < !E L E M E N T e n te r p r is e ( m a r k e t in g ) > < !E L E M E N T m a r k e t in g ( c u s t o m e r, p r o d u c t , s a le ) > < !E N T IT Y % c u s to m e r P U B L IC " h ttp ://e _ c o m _ o rg .c o m /c .d td " > < !E N T IT Y % p r o d u c t S Y S T E M " p .d td " > < !E N T IT Y % s a le P U B L IC " h tt p : // e _ c o m _ o r g .c o m / s . d t d " > ]> < e n te rp ris e > < m a r k e t in g < c u s to m e r > < !- - f u r t h e r c o n t e n t a n d s t r u c t u r e c o n f o r m in g to c . d td , a s e x e m p lif ie d b e lo w - - > < p o t e n tia l_ c u s to m e r > … < /p o t e n tia l_ c u s to m e r > < a c t u a l_ c u s t o m e r > … < / a c t u a l_ c u s t o m e r > < /c u s to m e r > < p ro d u c t> < !- - f u r t h e r c o n t e n t a n d s t r u c t u r e c o n f o r m in g to p . d t d , a s e x e m p lif ie d b e lo w - - > < m a r k e t_ p r o d u c t> … < /m a r k e t_ p r o d u c t> < m a n u fa c tu re d _ p r o d u c t> … < /m a n u fa c tu r e d _ p r o d u c t> < p ro d u c t> < s a le > < !- - f u r t h e r c o n t e n t a n d s t r u c t u r e c o n f o r m in g to s . d td , a s e x e m p lif ie d b e lo w - - > < fo r _ s a le > … < / f o r _ s a le > < s a le _ o f fe r > … < /s a le _ o f fe r > < /s a le > < /m a r k e tin g > < / e n t e r p r is e >L is tin g 1 . A n e x a m p le o f a n X M L d o c u m e n t
The processing of the XML document is carried recommendation (Bray et al, 1998) does notout by a parser, commonly with a compulsory specify which API to use. Our research utilises awell-formedness and an optional validation widely available API for XML processing knownchecking capability. as the XML Document Object Model (DOM) specification (Apparao, 1998). The above-A well-formed XML document is one that mentioned XML deployment process is depictedpossesses properly structured markup syntax, e.g. in Figure 4.the pairs of opened and closed tags or tags arenested properly. A validated XML document is Via the DOM interfaces, for example, a treeone that conforms to a schema construct or representation of the XML document is exposed,document type declaration, DTD (the section with whereby every construct in the XML document,<!DOCTYPE …]> in Listing 1). The DTD, such as an element or an attribute, is representedwhich may either be internally or externally as a node in the tree. The tree representation isdefined (i.e. pointed by the ENTITY XML designed with object-oriented principles thatkeywords), provides the rules for constructing the provides the advantage of object encapsulationstructure of an XML document. and reusability. Each node has its own set of C o n s u m in g A p p lic a t io n F u r th e r p ro c e s s in g / D O M In te rfa c e XM L No D ocum ent W e ll Yes Yes Yes fo rm e d ? DTD? V a lid it y ? DTD No No I s s u e w a r n in g / s to p p r o c e s s in gF ig u r e 4 . X M L d e p lo y m e n t p r o c e s sThe processed document containing the methods and properties, and inherits functionalityinformation to be exchanged, e.g. the captured from a base class, including commonontologies and their pertinent DTDs can then be functionality such as navigation through the treemade available to consuming applications. The and manipulation of contents of the nodes.DTD captured ontologies may be derived from Irrespective of the inclusion of an interface for theheterogeneous and distributed sources, each purpose of exposing XML document as a tree-likerelated to the representation of explicit structure of nodes that possesses properties andspecification of conceptualisation. In essence our methods to consuming applications, our researchopen metalanguage capturing process exposes the also investigates the use of templates ordistributed architecture of ontologies while stylesheets to present different views of the XMLallowing validation of extensibility processes such document. One particular XML-based stylesheetas accommodation of emergent viewpoints and language for stylesheets definition is theontologies. Extensible Markup Language StylesheetFurthermore, the inclusion of an additional layer Language (XSL) (Clark, 1999). By adopting theof abstraction, in the form of application use of stylesheets, we are able to reuse data inprogramming interfaces (API), between the XML defining presentation semantics by: transformingdocument and the application, provides methods the source XML document to multiple outputand properties to access and manipulate an XML formats such as HTML, Rich Text Format (RTF),document. Legacy systems can also use these or other forms of markup language systems; andinterfaces to provide access to legacy data as if performing dynamic customisation of presentationthe data was natively stored in XML (Ceponkus for user preferences. The XML/XSL deploymentand Hoodbhoy, 1999). The XML 1.0 process is depicted in Figure 5.
XM L D ocum ent XSL S ty le s h e e t ( fo r m a t t r a n s fo r m a t io n ) X S L a w a re B ro w s e r a n d C lie n t /S e r v e r - s id e A p p lic a tio n HTM L RTF O th e r M a rk u p O u tp u t O u tp u t Languages O u tp u t F ig u re 5 . X M L /X S L d e p lo y m e n t p ro c e s sIn summary, our research is investigating the use 3.3 Viewpoint Modelling andof appropriate markup elements and qualifiers, Analysisand the construction of DTDs, in order to supportgeneric enterprise model and deduced enterprise The resulting markup language-based ontologymodel requirements, as well as enabling information resource may be expressed in termsprogrammatic interfaces to architectural of many different viewpoint states. Our researchcomponent, consuming applications, and their addresses a wide range of pertinent issues to theservices. analysis of the viewpoints, including the construction of a novel viewpoint model thatAdditionally, our use of UML and object-oriented would accommodate the ontological aspects of theparadigm at the ontology representation phase is enterprise; identification of potential viewpointsextended to include the modelling of and their relevance to the ontology; the manner inmetalanguage capturing phase. In our research, which ontology influences the consistency ofthe mapping of domain knowledge (as qualified viewpoint specifications; and managingby the ontology) to the metalanguage information from these ontology viewpoints. Inrepresentation (as exemplified by the use XML essence, the ontology viewpoints are regarded aswith DOM interface) provides an integrated viewpoints that are committed to “an explicitmodelling solution as well as generation of code specification of conceptualisation”.skeletons as a base for the implementation phase.This can be further supplemented with user- Our research investigates the potential extensioncentric customisation of views or presentation of the model described in (Sommerville et al.,involved (as exemplified by the use of XSL). The 1998) and aims to establish the role of ontology inmodelling or code generation environment can structuring, analysing, and modelling viewpointsfurthermore be integrated with other development and their interactions. The conceptualenvironments such as agent and problem solving relationship for our viewpoint model is shown inor domain-oriented development tools. Figure 6.
C o n c e rn s B o t h , c o n c e r n s a n d v ie w p o in ts , a r e c o m m it t e d to t h e u n d e r ly in g o n t o lo g y . V ie w p o in t χ V ie w p o in t δ V ie w p o in t ε O n to lo g y F ig u r e 6 . C o n c e p tu a l r e la tio n s h ip b e tw e e n c o n c e r n s , v ie w p o in ts , a n d o n to lo g y 3.4 Middleware Support infrastructure such as the Internet and World Wide Web; middleware server environment;A middleware support framework is utilised as a ontology editor, repositories, processor andplatform to hold the various distributed and translator; viewpoint/domain-oriented services;heterogeneous components together. and agent-oriented services. The architecture, asAdditionally, the middleware support framework depicted in Figure 7, is further discussed below.aids software agents to enact their rolesautonomously in the distributed and The user/client connectivity to the World Wideheterogeneous environment. The framework Web utilises the ubiquitous hypertext transferfacilitates the potential migration of states and protocol (HTTP) for exchanging files on thecodes of the software agents (Wong et al., network infrastructure. This method of1999) in achieving flexibility of execution of connectivity allows for web editing and browsing-agent processes in the distributed and based implementations (such as editing andheterogeneous environment. The architecture, browsing of ontologies), as well as Transmissionconsidered in the context of current research and Control Protocol/Internet Protocol (TCP/IP)-its conceptual components, consists of the based transport of messages between systems andfollowing main parts: connectivity to a network architectural components. A g e n t - o r ie n te d S e r v ic e s V ie w p o in t / D o m a in - o r ie n te d S e r v ic e s O n to lo g y HTTP U s e rs M id d le w a r e E d it o r O n to lo g y R e p o s ito rie sF ig u re 7 . A rc h ite c tu re in th e c o n te x t o f th e re s e a rc h a n d its c o n c e p tu a l c o m p o n e n ts
Critically, the middleware server implementation need for shared ontology in supportingbehaves as an extensible, persistent host in data/knowledge translation and transformationproviding support for the distributed environment processes.in dealing with e.g. transaction management, loadbalancing, seamless accessibility and connectivity 3.5 Multiagent Systembetween architectural components and Software agents are used to automate the tasks ofheterogeneous systems including enterprise participating entities. For such a multiviewpointapplications and databases. Furthermore, an open system, a multiagent representation is beingimplementation, e.g. using the Java RMI generated. To enable effective communication oftechnology/XML open standards, aided by a knowledge between the agents, an appropriatedistributed object paradigm, enables component shared ontology is utilised to support the inter-reusability and open interface in achieving e.g. agent communication (Jones, 1998). Our researchdesired system interoperability, integration and on the accommodation of shared ontology looksextensibility. into its structural composition and how that can beThe ontology editor enables the construction of derived from the assumed ontology viewpointsontology as per domain. More importantly, the model. Additionally, the implementation ofontology capturing process is governed by software agents accommodates the metalanguageconstruction rules or mapping implemented using representation of the shared ontology. Thethe XML metalanguage standards described research is investigating the requirementsearlier. The research utilises appropriate markup involved in such metalanguage support inelements and qualifiers, i.e. through the facilitating inter-agent communication, e.g. inconstruction of DTDs, in order to support generic comparison to the use of other prominent agententerprise model and deduced enterprise model communication languages (ACLs) such as therequirements, as well as enabling programmatic Knowledge Query and Manipulation Languageinterfaces to architectural component, consuming (KQML) and the ACL of the Foundation forapplications, and their services. Intelligent and Physical Agents (FIPA) (Singh, 1998).The construction rules and captured ontologies arestored in repositories which are necessarilyrequired to support extensibility and connectivity 3.6 Integrationof the database of ontologies. In our research, in order to facilitate integration ofThe ontology processor provides well-formedness the conceptual components of ontology,and validity checking of captured ontologies viewpoints, and agent-middleware based supportagainst adopted construction rules, prior to framework we employ the open publishedallowing global accessibility of the captured standard of CORBA for system interoperabilityontologies via the ontology translator. As and within a distributed infrastructure, with supportwhen required, the ontology translator supports for standard services including directory,mapping processes between and within ontologies transactions and security. The CORBA basedfor validation and consistency checking infrastructure generally provides support for(including ontology mismatches); and between applications implemented in a range ofontologies and format requirements of the programming languages (e.g. C++, Java, C, andconsuming applications and their services. COBOL) and distributed system requirements, such as distribution, location, and networkingIn the research, the consuming applications and transparency.their services are perceived as agents andviewpoint/domain-oriented, whose operations are With the availability of Java Virtual Machinesenhanced via semantic transactions and (JVM) on environments, such as Microsoftinteroperability enabled by the captured Windows, IBM OS/2, and Apple Macintosh, weontologies and facilitated by the middleware utilise Java technology, e.g. Enterprise JavaBeansservices described earlier. programming as the means of writing portable and component-based application codes.Additionally, our research investigates theresponsiveness of the middleware support The selection of CORBA as the integrationframework to accommodate the requirements of infrastructure and provision of standard services,distributed ontology viewpoint services, e.g. the ensures that Java (technology) as well as other application environments, such as Microsoft
proprietary Component Object Model (COM), can • elimination of duplication of systemthen be successfully integrated. services and rationalising engineering andThe component-based solution is able to business processes.accommodate and integrate existing (legacy) as • design and implementation of a solution thatwell as new applications and services in achieving can scale easily to accommodate growth ofdesired functionality such as levels of availability, the enterprise as well as possessingperformance, and reliability of the integrated integration capability with other services,system. thereby increasing enterprise productivity and lowering costs.4. DISCUSSIONSThe novelty of our research and the simplicity of 5. CONCLUSIONthe architecture provide a generic framework for a The globalisation of enterprise activities is fuelledwide range of technological implementations. by the world-wide wave of the liberalisation ofOne emerging area in terms of meeting trade, investment and capital flow. This is furtherparticularly the needs of an agile enterprise is aided by the very rapid development ofenterprise application integration (EAI). The communication and information networks, the fastcentral theme of EAI is to achieve effective development of computer based productionintegration of one system with another, whether technologies and structures, and the spread ofnew or legacy systems. market-oriented economies, among others. TheThe conceptual and architectural components of global economic environment affects allour research provides a platform to enable an enterprises, whether they be catering to just theopen EAI (OEAI) through the integration of domestic markets or to international marketsontology-driven systems implemented by open (Prokopenko, 1999). One manifestation of thestandards in programmatic and metalanguage increasing pace of globalisation is thesupport. Such systems are characterised by a intensification of competitiveness within andnumber of factors, including: accessibility from across national boundaries; with competitionan Internet/web based infrastructure; support for increasing not only for international and domesticontology-driven enterprise/business processes markets of products and services but also inagainst the background of constant change of attracting the increasingly mobile investments andviewpoints and domain-oriented requirements; capital.support for distributed transactions; reusable Increasingly, the productivity of enterprises,component implementation and integration; which are set against the background of complex,system availability, performance, and reliability; distributed and heterogeneous environment, isand security service requirements. limited not by labour or capital, but byThrough OEAI, the integration of complex and information (Barbuceanu and Fox, 1994). Foroften disparate systems, i.e. within a distributed example, the enterprise facets of supply,and heterogeneous environment, enables production, assembly, distribution, and endenterprises to derive a number of important customer need to be sewn together from a systemadvantages. These advantages in the context of integration perspective, motivated by both theengineering enterprise agility and hence enterprise’s stakeholders and its informationsupporting the capability for an enterprise to be systems development.competitive are: The achievement of desired semantic • enhancing semantic interoperability between interoperability between enterprise systems must systems, and automation of domain-oriented necessarily be in parallel with the effort to (e.g. enterprise-critical) processes, while streamline the physical flow of the enterprise and exploiting and harmonising enterprise the integration of its processes. This, in turn resources. provides viewpoint or domain-oriented information and services as well as problem • extending applications to more customers solving methods that are responsive or agile to and product users and improving clientele competitiveness requirements, such as satisfying services (e.g. over a global or network- customer or market demands through the centric scale) and satisfying their provision of high quality product or services in requirements. the shortest time possible. The framework
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