A Semantic Web service-oriented application for ...

Int. J. Social and Humanistic Computing, Vol. 1, No. 2, 2009

A Semantic Web service-oriented application for mobility impaired users Dionysios D. Kehagias* and Dimitrios Tzovaras Informatics and Telematics Institute, Centre for Research and Technology Hellas, 6th Km Charilaou-Thermi Rd., GR-57001, Thermi, Thessaloniki, Greece E-mail: [email protected] E-mail: [email protected] *Corresponding author Abstract: This paper presents a service-oriented application whose purpose is to assist various activities of mobility impaired people as they move from one location to another. Such activities include trip planning, route guidance, e-working, e-learning, search for points of interest and social events among others. A number of registered web services provide all the required content and information that are displayed on the end-user device. Existing services are marked up by a number of domain ontologies about the information needs of mobility impaired users, in order to enable ontology-based search and retrieval of services. A service alignment tool has been developed to facilitate the markup process on behalf of service providers. After describing the architecture of the overall application and the involved mechanisms, we demonstrate a number of use cases that are enabled by the presented technologies. Keywords: web services; WS; ubiquitous computing; ontologies; mobility impaired users. Reference to this paper should be made as follows: Kehagias, D.D. and Tzovaras, D. (2009) ‘A Semantic Web service-oriented application for mobility impaired users’, Int. J. Social and Humanistic Computing, Vol. 1, No. 2, pp.149–162. Biographical notes: Dionysios D. Kehagias is a Postdoctoral Research Associate at the Informatics and Telematics Institute of the Centre of Research and Technology Hellas. His research interests include web services and service-oriented architectures, software programming environments, agent-oriented software engineering, knowledge discovery and Semantic Web technologies. He received his PhD in Computer Engineering from the Aristotle University of Thessaloniki, Greece. Dimitrios Tzovaras received the Diploma degree in Electrical Engineering and the PhD in 2-D and 3-D image compression from Aristotle University of Thessaloniki, Thessaloniki, Greece, in 1992 and 1997, respectively. He is currently a Senior Researcher Grade B in the Informatics and Telematics Institute of the Centre for Research and Technology Hellas in Thessaloniki, Greece. Prior to his current position, he was a Senior Researcher on 3-D imaging at the Aristotle University of Thessaloniki. His main research interests include virtual reality, assistive technologies, 3-D data processing, haptics and semantics in virtual environments.

Copyright © 2009 Inderscience Enterprises Ltd.

149

150

1

D.D. Kehagias and D. Tzovaras

Introduction

The realisation of the Semantic Web vision requires semantic markup of web-available information resources (Lytras and Garcia, 2008). Web service (WS) technology forms today the de facto middleware infrastructure for knowledge sharing among distributed web-based applications. WSs are appropriate to enable content on demand through suitable software interfaces. Despite the large amount of available services, only a small number of them are marked up today in order to be visible in specific contexts. Within the existing marked up WSs there is almost non-existent support for mobility impaired (MI) people needs. In order to overcome this shortcoming, semantic markup methods and tools for WSs that take into account MI user info-mobility needs are required. In particular, WSs should be appropriately described by domain ontologies that address MI user-specific needs. This will enable the realisation of a wide range of applications for MI users on which the required content will be searched and delivered through the appropriate WSs. Today, searching for WSs involves keyword search in universal description discovery and integration (UDDI) registries. This practice is inefficient and unreliable because it does not support service discovery based on service capabilities and special user needs. In particular, it leads to high recall, low precision or to low or no recall (Antoniou and van Harmelen, 2004). Semantic markup of WS by the use of ontologies aims at overcoming this inefficiency. In this paper, we present the underpinning infrastructure for the realisation of an ubiquitous end-user application that consumes semantically marked up WSs. The end-user application was developed in order to support the needs of MI users as they move from one location to another. Work reported in this paper has been developed in the context of the ASK-IT1 integrated project, partially funded by the eInclusion European initiative of the Information Society Technologies (IST) research priority. The ASK-IT technical infrastructure consists of a number of domain ontologies that describe MI user needs and relevant services. Most of the available WSs today are distributed under a commercial or open licence of use, represented by a specific authorised party known as service provider (SP). Most commercial SPs make their services available for a certain price that includes the cost of the intellectual capital of the services to be provided (Pike et al., 2006). Intended for SPs, ASK-IT is coupled with a tool that facilitates the integration of existing WSs into the common semantics context defined by the ontologies. By this tool, SPs become capable of registering their services in the ontological framework, thus, allowing their efficient retrieval by semantic querying engines, developed within the project. Two important initiatives have emerged with respect to ontological descriptions of WSs: OWL-S and web service modelling ontology (WSMO). OWL-S, which is based on the Web Ontology Language (OWL) defines an upper ontology in the form of a generic service concept. In order to make use of OWL-S upper ontology, the lower ontological levels must be defined. WSMO seeks to create ontologies for describing various aspects related to Semantic Web services, aiming at solving the integration problem (Roman et al., 2005). WSMO takes the web service modelling framework (WSMF) (Fensel and Bussler, 2002) as starting point and further refines and extends its concepts. Web service modelling execution environment (WSMX) is an execution environment for dynamic discovery, selection, mediation and invocation of WSs based on WSMO (Haller et al., 2005).

A Semantic Web service-oriented application for mobility impaired users

151

In most cases, ontological descriptions for WSs are used to support service discovery. For instance, in Ramachandran et al. (2006), an inference engine is used to submit queries to an ontology about atmospheric data. An alternative method in Hübner et al. (2004) uses a Semantic Web enabled search engine in order to perform discovery of interconnected and semantically unified geographic information resources. Sriharee (2006) develops ontologies to describe a rating model that is used for more accurate WS discovery results. In Zhang and Li (2005), an ontology-based knowledge base about WSs is constructed in order to facilitate the discovery of WSs. Semantic markup of WSs also enables information sharing among different distributed resources. A survey of information sharing techniques is reported in Rafaeli and Raban (2005). ASK-IT aims at the provision of personalised content and services for MI users. The concept of content personalisation, when content is derived from a set of semantically marked up WSs, is linked to relevant Semantic Web and ontologies research efforts, like the ones reported in Vargas-Vera and Lytras (2008). Many tools have been also developed to facilitate the description of WSs in ontological terms. Such a tool, called WSDL2OWL-S (Paolucci et al., 2003), converts WSs descriptions from the Web Service Description Language (WSDL) to OWL-S. This allows the automatic provision of ontological descriptions for already existing services. Although promising, this tool as well as its supporting transformation process from WSDL to OWL-S is still in its infancy and requires manual intervention on a practical level. This is mainly due to the fact that OWL-S is richer than WSDL in semantics. Thus, the transformation from WSDL to OWL-S is a semantics-loss process. In order to overcome the lack of semantics in WSDL, a proposal was submitted, available as a World Wide Web Consortium (W3C) recommendation (Akkiraju et al., 2005) that introduces WSDL-S, an effort to enhance WSDL expressiveness by adding semantics in it. Although promising, this effort suffers from limited support by existing tools. Another noticeable tool that defines a repository of objects with semantic access is ROSA (Porto et al., 2007), which designs a data model on top of the resource description framework (RDF). This data model contains ordered collections and relationship properties and cardinalities. ROSA deploys a query engine that supports ROSA operations and data structures. The purpose of ROSA is to enable efficient storage and access to e-learning resources. None of the aforementioned systems use any tool to facilitate the integration of existing WSs by the corresponding SPs in the way it is supported in ASK-IT. As opposed to these systems, our framework provides a service alignment tool (SAT) that allows SPs to register their services within the context of a set of domain ontologies. A similar functionality is supported by the BioMoby project (Gordon et al., 2007) that involves WSs annotation by the use of ontologies for biomedical data. BioMoby is also based on a repository of registered services and efficient ontology-based search and retrieval of the registered services is supported. This paper is structured as follows: next section presents the overall system architecture with a special focus on the back-end mechanism that supports service retrieval and invocation. Section 3 provides an overview of the ontological framework, which provides the required ontologies on which the service discovery and invocation processes are relied. Section 4 describes the service alignment process and explains how this is performed by the registered SPs by the use of the SAT. Several indicative use

152


cases that are realised via the proposed infrastructure are described in Section 5, while Section 6 concludes the paper and outlines future work.

2

Overall system architecture

In general, the ASK-IT ambient intelligence framework relies its functionality on a back-end subsystem, whose responsibility is to handle communication with the available services in order to retrieve the appropriate content upon user request. This subsystem is also known as service side layer of ASK-IT. Figure 1 depicts the interoperations occurring between the basic modules of the server side layer as well as any external actors or any other layer components. Figure 1

The overall architecture of the ASK-IT back-end system (see online version for colours)

Service Provider Registers Services

Service Alignment Tool Gets service descriptions

Ontology Author Ontology Development

Maps and stores services

Ontology

Indexes

Service Repository

Ontological Framework

MI user

Request for Services

Delivers Content

Queries

Replies

Query Engine

Wrapper Invokes WS

DMM

Mobile devices – client apps

Web

Web Services

Notes: As soon as a request for service is launched by the client user application, the DMM submits a semantic query to the ontological framework in order to retrieve the appropriate service. The retrieved service is invoked by the corresponding wrapper via SOAP messages exchange.


153

The data management module (DMM) handles incoming user requests for services. The DMM listens to the request, decomposes it, searches for the appropriate services through the query engine and retrieves the service that best fulfils the user request. In the back-end system architecture the following units are included: 1

SAT. This component provides a common interface for SPs in order to register their services according to the descriptors supported by the ASK-IT ontologies. As soon as a new service is registered, its location is stored in a service repository.

2

The ontological framework consists of the overall ontology, which consists of a number of domain-specific ontologies and the service repository. An ontology author is granted access to the ontology in order to perform modifications on it. The service repository acts as an index of services, which are linked to the ontology. The structure of the overall ontology and the separate domain-specific ontologies are presented in Section 3.

3

The DMM supports the following operations: •

It manages incoming requests for services. It processes the requests via a query engine that submits the appropriate semantic queries to the ontological framework. After processing the DMM request, the ontology replies by a list of retrieved services and their locations.

•

It also performs invocation of real WSs via the corresponding wrapper, a client application, which is aware of the valid mappings that should occur between real WS data types and the ones defined in the ontology. In this way, the wrapper becomes capable to invoke the real service when receives a request for service invocation in the common ontological format. It finally wraps content returned by the previously invoked WS and sends it back to the user application in the common ontological format.

Content exchange between DMM and real WSs is performed by appropriate messages defined in the Simple Object Access Protocol (SOAP). More details on service invocation are provided in Section 4.

3

The domain ontologies

The development of the ontologies was originally motivated by the need for providing elderly and disabled users with accurate information that describes the specificities of their various impairment types. For the development of the ontologies, several existing ontologies and tools related to MI users were investigated. For instance, in Yesilada et al. (2005), the authors introduce a semi-automated tool that supports travel and mobility of visually impaired users. This tool transforms existing web pages, by using travel ontology, in order to extract information that may be relevant to visually impaired users. Work described in Karim and Tjoa (2006) defines an ontology that enables mappings amongst various impairments and attributes of user interfaces. This improves access to personal information systems by making it possible for user interface developers to adapt them to the user needs. The ontology covers many MI user attributes following a similar approach to the one adopted by the ASK-IT project. Although many advanced use cases,

154


such as trip planning, can be realised, the main focus remains on the user interface customisation according to user impairments. Along with the aforementioned approaches, which focus on the attributes of MI users, additional efforts were also taken into account, including more generic ontologies that have been applied in similar application domains, such as travelling, tourism and leisure information. These ontologies, however, fail to address the specific characteristics of the MI user information needs required for advanced usage scenarios, such as route guidance, planning, searching for accessible social events, etc. A typical example of a common travel ontology can be found in Choi et al. (2006). As opposed to this ontology, the corresponding ASK-IT domain ontology, which is relevant to transportation, includes information about the accessibility status of the involved concepts. The ASK-IT specific ontologies are classified according to the following domains. •

Service ontology. This ontology includes skeleton descriptions about the supported services. The main purpose of this domain is to enable efficient search and retrieval of WSs, through appropriate interfaces, when the requesting party is aware of the use case in which the user is acting. It provides interrelationships between the user groups, use cases categories and existing service types. A fragment of this ontology is illustrated in Figure 2.

•

Transportation ontology. This ontology includes transport-related information and data types, which can be filled in by content providers and serve a variety of MI people levels of accessibility.

•

Tourism and leisure ontology. Tourism-related content is defined as anything that would interest a tourist who visits an area or city. This include, among others, useful content about hotels, museums, interesting places as well as information about tourism offices, embassies, airlines, useful telephone numbers and addresses and so on.

•

Personal support services ontology. This ontology includes information about travel companion, specific care at the hotel, eating, paramedical support, etc. These services will be used by MI people who seek to hire local assistance that matches their needs (including language, expertise, specific preferences).

•

E-learning and e-working ontology. It includes concepts based on services for work and education on a long distance basis with special considerations for MI user groups.

•

Social relations and community building ontology. This ontology contains information about social relations, registration to communities and social events. It mainly includes specific aspects of assisting devices, which play a significant role to the establishment of social relations between users. In addition, the ontology contains concepts related to potential meeting places as well as community registration procedures for all supported user groups.

The aforementioned ontologies have been authored using the Protégé tool (Noy et al., 2004) and they are stored in the description logics flavour of OWL (OWL-DL), because the latter is widely supported by the most common tools and represents the most stable standard among the ontology description languages which are available today. All ontologies include more than 1,400 concepts and 1,100 relationships.

A Semantic Web service-oriented application for mobility impaired users Figure 2

4

155

ASK-IT domain ontologies describe services, use cases, user groups and additional concepts related to MI people information needs (see online version for colours)

The service alignment tool

Service alignment is the process of registering an existing WS into the back-end subsystem of the ASK-IT framework so that it adheres to the ontological definitions of services. This process is performed by any SP who is interested to provide one or more services that deliver content in the one of the application domains and for those user groups that are defined in the context of the ASK-IT project. Service alignment is facilitated by the SAT, which is equipped with a web-based user-friendly interface, shown in Figure 3. The aforementioned process results into the completion of service integration whose purpose is to enable the efficient invocation of services whenever it is requested by any of the integrated client applications.

4.1 Service integration SPs participate in the service alignment process by being able to establish relationships between the services and the ontologies. WSs are described in the service ontology by the service model that defines the operations and the structure that should characterise any registered WS. Before the alignment takes place, SAT collects information about the SPs. Any registered provider has the ability to navigate through the supported models as these are defined in the service ontology. SPs correlate their WSs with the ontologies. By doing so, WSs are consistently marked up. The alignment mechanism facilitates a flexible standardisation process. In this context, ‘similarity’ between the ontology and the WS is established when the following criteria are satisfied:

156


•

the inputs of the supported WS operations are identical to the inputs provided by the service model’s operations

•

the outputs of the real WS operations are described by the outputs provided by the service model in the ontology.

Figure 3

A snapshot of the SAT user interface (see online version for colours)

Notes: SPs may exploit drag-and-drop functionality in order to provide mappings of data types and operations defined in their services to the corresponding fields defined in ASK-IT ontology services.

The SAT allows any SP to see the ontological operations that are defined in similar manner to those appearing in a WSDL file. Furthermore, by clicking on the operation models, SPs can get information about the inputs and outputs that their services must have in order to comply with the model. After the identification of the appropriate model, the providers should select from a drop-down list the operation that complies with the service they want to register. Thus, they provide the uniform resource identifier (URI) of the WSDL file that describes the service. At this point, the tool automatically parses the WSDL file and extracts the required information. In this context, any service can be described by the triplet: S =< P _ id , wsdl, op[ ] > ,

where P_id is the provider’s identifier, wsdl is the URI to the WSDL service description and, op is a list of defined operations. Each operation is defined as: op =< name, i1 , …, in , o >,

where name is the name of the operation, i1, …, in its inputs and o its output. Let us assume that service S is described in the ontology by the service ontological representation Sm. Two arbitrary operations op ∈ S and opm ∈ Sm have a degree of similarity equal to 1, when they have equal number of inputs and also: ik ≡ imk and o ≡ om, ∀ik , o ∈ op and imk , om ∈ opm , where k = 1… n.


157

The alignment process, which is performed by the provider initially determines the degree of similarity between the operation defined in the ontology and the one that has been selected to be included as part of a registered service. It is up to the SP to verify the accuracy of the alignment operation and select the service to be aligned. The last step of the service alignment procedure involves mapping of inputs and outputs between the service to be aligned and the ASK-IT ontological service model. This process, which is supported by drag and drop operations on the GUI is illustrated in the snapshot of Figure 3. Once this final step is completed, the information of the alignment operation is stored in a registry of services, known as service repository. In this way, the invocation of services is enabled through the back-end system. The invocation mechanism handles incoming requests for specific content by the client applications and launches the appropriate services in order to receive the required content.

4.2 Service invocation As soon as a service alignment process is completed, the newly aligned service is integrated within the system’s back-end and at the same time a new entry is added in the service repository. Actual service integration involves manual generation and compilation of the required source code of the wrapper that corresponds to the newly aligned service. This wrapper provides the necessary mappings and transformations between SP’s native data type formats and the ASK-IT ontological description of data types and services. After the completion of the alignment process, the invocation of the real WSs is then performed based on SOAP. Each WS is described by a WSDL file, which contains a complete description of the WS that facilitates the invocation process. This software, often referred to as the WS client stub is a WS client. Thus, in order for the DMM to be able to access a WS, it should have the client stub code of the integrated service, which provides the ability to call the service each time this is requested by the user interface.

5

Usage scenario

In the ASK-IT framework, a wide range of services have been defined with respect to the following domains: •

transportation

•

tourism and leisure

•

personal support services

•

work, business and education

•

home automation

•

social relations and community building.

All content, required for the implementation of the various use cases, becomes available through a set of WSs. The required content is being rendered on the user device, each time a user sends a request via the user interface for a particular type of content. It should

158


be noted that the whole process of service search, selection and invocation is executed in a seamless way on behalf of the users. For example, a user who is interested in finding information about the available restaurants that are located within a specific range activates the search for points of interest (POI) application performing the following actions: •

selects the restaurant POI type from a drop-down list

•

specifies the range (e.g., 1 km)

•

provides accessibility preferences of the POIs to be returned (optional)

•

presses a ‘search’ button on the user interface.

Figure 4

Snapshots of the ASK-IT PDA end-user application (see online version for colours)

1 2

3

7

4

5

6

8

Notes: The following services are supported: (1) indoor and (2) outdoor localisation (3) POI search (4) indoor and (5) outdoor route guidance (6) search for social events (7) distance learning and (8) working.

The user interface then sends a request for a list of POIs to the DMM. A service search and retrieval mechanism submits a semantic query to the ontology requesting a list of POI search services. Among the returned services, the one that is ranked first according to a set of quality of service (QoS) criteria is selected for invocation and then a message is sent to the DMM. In practice, this is performed by a filtering mechanism that ranks the returned results according to the user’s previous choices. This mechanism is similar to the


159

one described in Panagis et al. (2006). After this step, the appropriate wrapper is activated whose responsibility is to transform user input into the particular WS-specific format. The wrapper finally invokes the service providing the right values for its parameters. The main QoS criteria that are taken into account for the invocation of services include: •

The frequency of use of the particular service, i.e., how many times the user has requested invocation of this service.

•

The geographical location of the service. This is especially necessary in order to make sure that the selected service will provide localised or location-specific information, which is required in a mobile and ubiquitous environment.

In the most common use cases, users request the availability of general-purpose location-aware, localisation, guidance and travel assisting services. Figure 4 shows a number of such use cases, assuming that the user is equipped with a Java-enabled PDA device with an integrated GPS sensor. All these use cases involve user requests for content that is available via a set of registered WSs. For each user request for content, a corresponding WS is invoked that has been aligned on the grid. All screenshots of the main application shown in Figure 4 are displayed on a device running Java J9 version 1.4 under Windows Mobile version 6.0. The following use cases and the corresponding end-user services are displayed. 1

Indoor user localisation. Users send through the user interface a request for a localisation service. This service actually returns a map that shows the user’s current location. When a user is located inside a building, an appropriate network of indoor location-aware sensors (e.g., Zigbee devices) is required in order for the service to be able to locate the user position. In this case, an indoor map is displayed by the invocation of the appropriate WS.

2

Outdoor localisation. The localisation operation supports seamless transition between indoor and outdoor maps. Once the user leaves an indoor area, the map that displays the current user position automatically (‘seamlessly’) changes to an outdoor map. In outdoor mode, the user position is received via the GPS sensor. The opposite action is also supported, i.e., when the user goes from outdoors to indoors, the map changes back to an indoor map.

3

Search for POIs. This facility allows the user to search for POIs of specific type (e.g., museums, restaurants, etc.). Information about the requested POIs is based on the user profile and specific type of impairment. After the user receives a list of available points of interest, route guidance capability is enabled, as an integrated facility, in order to guide users to the place chosen from the list of POIs.

4

Indoor route guidance. Route guidance is also available as a stand-alone service, activated on demand. Users may explicitly request to be guided to any POI via accessible routes, starting form an indoor location.

5

Outdoor route guidance. The route guidance service is offered for both indoor and outdoor locations. The invocation of this service results in a route drawn on a map that the user should follow in order to reach the requested destination. As the user moves from an indoor place to an outdoor area, the map changes accordingly.

160


6

Search for social events. The user is able to request a list of social events that may occur nearby. As soon as the users select a specific social event and express their interest in this event, the route guidance service is invoked in order to show them how to move to the place of interest.

7

Distance learning. The ASK-IT distance learning functionality contains a set of services and tools to facilitate courses taken on a long distance basis.

8

Distance working supports e-working capabilities (e-mail, calendar, document authoring), which are enable by the invocation of the corresponding WS.

6

Implications and future work

The ASK-IT project was developed in order to facilitate mobility of MI users. Until today, the overall framework – composed of the back-end subsystem and a number of client applications – has been successfully tested at seven pilot sites, hosted by an equal number of European cities. Specifically, the pilot sites were Newcastle (UK), Nuremberg (Germany), Genoa (Italy), Helsinki (Finland), Bucharest (Romania), Athens and Thessaloniki (Greece). For the purpose of running successful demo applications, local SPs and stakeholders from various municipal or national organisations for each one of the aforementioned cities prepared one or two-day events to demonstrate the client applications and how content is retrieved from real WS. The basic requirement for the operation of the framework on a municipality level is the availability of a set of local SPs to provide localised services and the integration of these services into the ASK-IT framework. Based on experience from the pilot demonstrators, the social impact of ASK-IT may be outlined as follows: •

ASK-IT facilitates the provision of information and services to the user groups of MI and disabled people, thus, reducing social isolation and enabling the exploitation of IT on behalf of these people.

•

It introduces new opportunities for education, work and community building on behalf of MI people.

The SAT and the relevant supporting process defined in the context of ASK-IT can be also seen as a substantial contribution towards the facilitation of the provision of the available information, which is available through WSs. In particular, from a technical perspective, SAT: •

Enables an ontological description of services in a particular context specified by the information needs of MI users. Even though ASK-IT targets MI users, the presented technical infrastructure may be generalised and applied on different contexts and application domains.

•

Provides a technical infrastructure for the realisation of ontology-based search and retrieval of Semantic WSs

•

Allows existing SPs to integrate their services without prior knowledge of software programming.


161

A set of enhancements have been considered as future work. These mainly concern the automation of some operations that are now performed in a manual or semi-automatic manner. In particular, one enhancement of the presented tool foreseen is the automation of the source code generation that is required each time a new service is being integrated through the service alignment process.

References Akkiraju, R., Farrell, J., Miller, J., Nagarajan, M., Schmidt, M., Sheth, A. and Verma, K. (2005) ‘Web service semantics - WSDL-S’, Technical report, W3C member submission, available at http://www.w3.org/Submission/WSDL-S/ (accessed on 6 October, 2008). Antoniou, G. and van Harmelen, F. (2004) A Semantic Web Primer, MIT Press. Choi, C., Cho, M., Kang, E.Y. and Kim, P. (2006) ‘Travel ontology for recommendation system based on semantic web’, The 8th International Conference on Advanced Communication Technology (ICACT-2006), pp.624–627, IEEE Press. Fensel, D. and Bussler, C. (2002) ‘The web service modelling framework WSMF’, Electronic Commerce Research and Applications, Vol. 1, No. 2, pp.113–137. Gordon, P.M.K., Trinh, Q. and Sensen, C.W. (2007) ‘Semantic Web service provision: a realistic framework for bioinformatics programmers’, Bioinformatics, Vol. 23, No. 9, pp.1178–1180. Haller, A., Cimpian, E., Mocan, A., Oren, E. and Bussler, C. (2005) ‘WSMX – a semantic service-oriented architecture’, Proceedings of the 1st International Conference on Web Services, pp.321–328, IEEE Press. Hübner, S., Spittel, R., Visser, U. and Vögele, T.J. (2004) ‘Ontology-based search for interactive digital maps’, IEEE Intelligent Systems, Vol. 19, No. 3, pp.80–86. Karim, S. and Tjoa, A.M. (2006) ‘Towards the use of ontologies for improving user interaction for people with special needs, in K. Miesenberger et al. (Eds.): Computers Helping People with Special Needs, ICCHP 2006, LNCS 4061, pp.77–84, Springer, Berlin/Heidelberg. Lytras, M.D. and Garcia, R. (2008) ‘Semantic Web applications: a framework for industry and business exploitation – what is needed for the adoption of the Semantic Web from the market industry’, Int. J. of Knowledge and Learning, Vol. 4, No. 1, pp.93–108. Noy, N.F., Sintek, M., Decker, S., Crubezy, M., Fergerson, R.W. and Musen, M.A. (2004) ‘Creating Semantic Web contents with Protege-2000’, IEEE Intelligent Systems, Vol. 16, No. 2, pp.60–71. Panagis, Y., Sakkopoulos, E., Garofalakis, J. and Tsakalidis, A. (2006) ‘Optimisation mechanism for web search results using topic knowledge’, Int. J. of Knowledge and Learning, Vol. 2, Nos. 1/2, pp.140–153. Paolucci, M., Srinivasan, N., Sycara, K. and Nishimura, T. (2003) ‘Towards a semantic choreography of web services: from WSDL to DAML-S’, Proc. 2003 International Conference for Web Services, pp.22–26, IEEE Press. Pike S., Boldt-Christmas, L. and Roos, G. (2006) ‘Intellectual capital: origin and evolution’, Int. J. of Learning and Intellectual Capital, Vol. 3, No. 3, pp.233–248. Porto, F., Moura, A.M.C., Silva, F.J.C. and Fernandez, A.P. (2007) ‘The ROSA project: leveraging e-learning to a semantic layer’, International Journal of Knowledge and Learning, Vol. 3, No. 1, pp.46–75. Rafaeli, S. and Raban, D.R. (2005) ‘Information sharing online: a research challenge’, Int. J. of Knowledge and Learning, Vol. 1, Nos. 1/2, pp.62–79. Ramachandran, R., Movva, S., Graves, S. and Tanner, S. (2006) ‘Ontology-based semantic search tool for atmospheric science’, preprints, 22nd International Conference on Interactive Information Processing Systems (IIPS).

162


Roman, D., Keller, U., Lausen, H., De Bruijn, J., Lara, R., Stollberg, M., Polleres, A., Feier, C., Bussler, C. and Fensel, D. (2005) ‘Web service modeling ontology’, Applied Ontology, Vol. 1, No. 1, pp.77–106. Sriharee, N. (2006) ‘Semantic Web services discovery using ontology-based rating model’, Proceedings of the 2006 IEEE/WIC/ACM International Conference on Web Intelligence, pp.608–616, IEEE Press. Vargas-Vera, M. and Lytras, M.D. (2008) ‘Exploiting semantic web and ontologies for personalised learning services: towards semantic web-enabled learning portals for real learning experiences’, Int. J. of Knowledge and Learning, Vol. 4, No. 1, pp.1–17. Yesilada, Y., Harper, S., Goble, C. and Stevens, R. (2005) ‘Screen readers cannot see (ontology based semantic annotation for visually impaired web travellers)’, in Koch, N., Fraternali, P. and Wirsing, M. (Eds.): Web Engineering – 4th International Conference, ICWE 2004 Proceedings, LNCS 3140, pp.445–458, Berlin, Springer. Zhang, P. and Li, J. (2005) ‘Ontology assisted web services discovery’, Proceedings of the 2005 IEEE International Workshop on Service-Oriented System Engineering, pp.45–50, IEEE Press.

Notes 1

Project full name: Ambient Intelligence System of Agents for Knowledge-based and Integrated Services for Mobility Impaired users. ASK-IT website is available at http://www.ask-it.org.