Semantic Services Research Articles

Dynamic invocation of semantic Web services that use unfamiliar ontologies

The semantic Web research community has developed ontologies and languages for semantically describing Web services. For example, OWL-S is an ontology developed using the OWL semantic Web description language. The purpose of OWL-S, formerly DAML-S, is to describe Web services so that software agents can read these descriptions and reason about how to interact with the services they describe. These efforts aim to facilitate interactions with services when the client agents lack built-in code for invoking those services' APIs&just as people can effectively use Web sites they've found through search engines. For example, without any reprogramming, a software system could have the flexibility to use various services that do the same kind of job but have different APIs. This can be useful in a number of situations, such as when a familiar service's API has changed or when the API is unavailable but a discovered new service could do the job. These semantic service descriptions also make it easier to compose services, by enabling reasoning about how to transform one service's outputs into another's inputs.

Functional Validation in Grid Computing

The development of the World Wide Web has changed the way we think about information. Information on the web is distributed, updates are made asynchronously and resources come online and go offline without centralized control. Global networking will similarly change the way we think about and perform computation. Grid computing refers to computing in a distributed networked environment where computing and data resources are located throughout a network. In order to locate these resources dynamically in a grid computation, a broker or matchmaker uses keywords and ontologies to describe and specify grid services. However, we believe that keywords and ontologies can not always be defined or interpreted precisely enough to achieve deep semantic agreement in a truly distributed, heterogeneous computing environment. To this end, we introduce the concept of functional validation. Functional validation goes beyond the symbolic level of brokering and matchmaking, to the level of validating actual functional performance of grid services. In this paper, we present the functional validation concept in grid computing, analyze the possible validation situations and apply basic machine learning theory such as PAC learning and Chernoff bounds to explore the relationship between sample size and confidence in service semantics.

Semantic services for grid-based, large-scale science

The process of large-scale science must evolve to facilitate the next steps of scientific discovery. Grid technology and semantic tools will be valuable in dealing with the complex multidisciplinary simulation and data environments that next-generation science will require. We envision semantic Web-like tools that automatically check the validity of sequences of composed operations and data, and automatically construct intermediate steps in a loosely specified sequence. These tools should also automatically construct sequences of operations that are consistent with a discipline model representing permitted relationships among simulation and analysis operations and data for particular disciplines, such as climatology or high-energy physics. These tools are called semantic services.

Towards a Protocol for the Attachment of Metadata to Grid Service Descriptions and Its Use in Semantic Discovery

Service discovery in large scale, open distributed systems is difficult because of the need to filter out services suitable to the task at hand from a potentially huge pool of possibilities. Semantic descriptions have been advocated as the key to expressive service discovery, but the most commonly used service descriptions and registry protocols do not support such descriptions in a general manner. In this paper, we present a protocol, its implementation and an api for registering semantic service descriptions and other task/user‐specific metadata, and for discovering services according to these. Our approach is based on a mechanism for attaching structured and unstructured metadata, which we show to be applicable to multiple registry technologies. The result is an extremely flexible service registry that can be the basis of a sophisticated semantically‐enhanced service discovery engine, an essential component of a Semantic Grid.

Market Intelligence Portal: An entity-based system for managing market intelligence

Gathering market intelligence (MI) can be critical for the success of an enterprise, and in-depth analysis of this information is helpful in understanding products, business trends, and information concerning competitors. Because of the huge volume of this information and the high rate of its growth, there is a great demand from enterprises for automated MI management systems. In this paper, an information portal for MI management systems is presented. It is based on a semantic web approach and provides the user a single access point for all relevant information about a specific MI topic. In contrast with traditional knowledge portal methods, our work is based on entity-level computing technologies rather than document-level technologies. We present a knowledge network called EntityNet, which is generated by an information synthesis process and enables the network to store entity-level knowledge and provide semantic services for the knowledge worker. From the systems perspective, EntityNet's most significant features are its customized document-processing flow and personalized category view. The framework can integrate various text collections, apply data-mining and dissemination functions on the collections with a defined process flow, and present a personalized browsing and searching interface.

Toward high-precision service retrieval

Online repositories are increasingly called on to provide access to services that describe or provide useful behaviors. Existing techniques for finding services offer low retrieval precision, returning many irrelevant matches. We introduce a novel service retrieval approach that captures service semantics using process models, and applies a pattern-matching algorithm to find the services with the behavior the user wants. Evaluations suggest that process-based queries offer substantially greater retrieval precision than existing approaches and scale well with the number of services being accessed.

Clustering support and replication management for scalable network services

The ubiquity of the Internet and various intranets has brought about widespread availability of online services and applications accessible through the network. Cluster-based network services have been rapidly emerging due to their cost-effectiveness in achieving high availability and incremental scalability. We present the design and implementation of the Neptune middleware system that provides clustering support and replication management for scalable network services. Neptune employs a loosely connected and functionally symmetric clustering architecture to achieve high scalability and robustness. It shields the clustering complexities from application developers through simple programming interfaces. In addition, Neptune provides replication management with flexible replication consistency support at the clustering middleware level. Such support can be easily applied to a large number of applications with different underlying data management mechanisms or service semantics. The system has been implemented on Linux and Solaris clusters, where a number of applications have been successfully deployed. Our evaluations demonstrate the system performance and smooth failure recovery achieved by proposed techniques.

SGrid: a service-oriented model for the Semantic Grid

This paper presents SGrid, a service-oriented model for the Semantic Grid. Each Grid service in SGrid is a Web service with certain domain knowledge. A Web services oriented wrapper generator has been implemented to automatically wrap legacy codes as Grid services exposed as Web services. Each wrapped Grid service is supplemented with domain ontology and registered with a Semantic Grid Service Ontology Repository using a Semantic Services Register. Using the wrapper generator, a finite element based computational fluid dynamics (CFDs) code has been wrapped as a Grid service, which can be published, discovered and reused in SGrid.

Semantic services

A hot topic at this year's World Wide Web conference was the convergence of Web services and the Semantic Web. What kind of formats can we reasonably expect? We want two things from our descriptive logic: fast computability and rich expressiveness. Unfortunately, these are incompatible goals; richer logics are the royal road to exponential complexity and noncomputability. Ultimately, semantic descriptions of Web services will arise through human processes, either because committees get together and create standards for particular subdomains or because a particular style used by some influential service providers comes to be commonly adapted.

A SUITE OF DAML+OIL ONTOLOGIES TO DESCRIBE BIOINFORMATICS WEB SERVICES AND DATA

The growing quantity and distribution of bioinformatics resources means that finding and utilizing them requires a great deal of expert knowledge, especially as many resources need to be tied together into a workflow to accomplish a useful goal. We want to formally capture at least some of this knowledge within a virtual workbench and middleware framework to assist a wider range of biologists in utilizing these resources. Different activities require different representations of knowledge. Finding or substituting a service within a workflow is often best supported by a classification. Marshalling and configuring services is best accomplished using a formal description. Both representations are highly interdependent and maintaining consistency between the two by hand is difficult. We report on a description logic approach using the web ontology language DAML+OIL that uses property based service descriptions. The ontology is founded on DAML-S to dynamically create service classifications. These classifications are then used to support semantic service matching and discovery in a large grid based middleware project [Formula: see text]. We describe the extensions necessary to DAML-S in order to support bioinformatics service description; the utility of DAML+OIL in creating dynamic classifications based on formal descriptions; and the implementation of a DAML+OIL ontology service to support partial user-driven service matching and composition.

Personalised Grid service discovery

The authors take a broad view that ultimately Grid- or Web-services must be located via personalised, semantic-rich discovery processes. They argue that such processes must rely on the storage of arbitrary metadata about services that originates from both service providers and service users. Examples of such metadata are reliability metrics, quality of service data or semantic service description markup. The paper presents UDDI-MT, an extension to the standard UDDI service directory approach that supports the storage of such metadata via a tunnelling technique that ties the metadata store to the original UDDI directory. They also discuss the use of a rich, graph-based RDF query language for syntactic queries on this data. Finally, they analyse the performance of each of these contributions in their implementation.

P2P M-commerce in pervasive environments

Pervasive environments are characterized by the presence of wireless devices ranging from sensors to mobile PDA-phones to laptops. Peer-to-Peer (P2P) information sharing in such environments presents a tremendous opportunity for people and devices to exchange information such as music, pictures, documents and stock tickers with peers. Information that has a monetary value introduces a whole new set of problems for P2P interaction in pervasive environments. In this work, we present the design of a middleware that attempts to solve these problems using concepts of the Contract Net Protocol, Semantic Service Discovery and secure transaction protocols.

Group communication specifications

View-oriented group communication is an important and widely used building block for many distributed applications. Much current research has been dedicated to specifying the semantics and services of view-oriented group communication systems (GCSs). However, the guarantees of different GCSs are formulated using varying terminologies and modeling techniques, and the specifications vary in their rigor. This makes it difficult to analyze and compare the different systems. This survey provides a comprehensive set of clear and rigorous specifications, which may be combined to represent the guarantees of most existing GCSs. In the light of these specifications, over 30 published GCS specifications are surveyed. Thus, the specifications serve as a unifying framework for the classification, analysis, and comparison of group communication systems. The survey also discusses over a dozen different applications of group communication systems, shedding light on the usefulness of the presented specifications. This survey is aimed at both system builders and theoretical researchers. The specification framework presented in this article will help builders of group communication systems understand and specify their service semantics; the extensive survey will allow them to compare their service to others. Application builders will find a guide here to the services provided by a large variety of GCSs, which could help them choose the GCS appropriate for their needs. The formal framework may provide a basis for interesting theoretical work, for example, analyzing relative strengths of different properties and the costs of implementing them.

Correlates of hospitalized patients' perceptions of service quality.

The purpose of this study was to examine hospital patients' perceptions of service quality in relation to four independent variables: (a) nurses' perceptions of human resource practices, (b) nurses' perceptions of autonomy in practice, (c) patient satisfaction with nursing care, and (d) patients' perceptions of organizational climate for service. The sample consisted of 102 nurse-patient dyads in an acute care hospital. Patients responded to the Modified Health Care Service Performance Instrument, the revised LaMonica-Oberst Patient Satisfaction Scale, and the Organizational Climate for Service Semantic Differential. Nurses responded to the Employee Turnover Diagnostic and the Dempster Practice Behaviors Scale. Two of the four correlational hypotheses were supported. Patient satisfaction with nursing care and patients' perceptions of organizational climate for service were each positively related to patients' perceptions of service quality. A multivariate regression hypothesis was not supported. Failure to support two theoretically based correlational hypotheses may be related to methodological problems experienced with dyadic research.

Dynamic Integration in Multidatabase Systems

The first step in interoperating among multidatabases is semantic integration: Producing attribute correspondences that describe relationships between attributes or classes in different database schemas. Dynamic integration requires the ability to automatically extract database semantics, express them as metadata, and match semantically equivalent data elements to produce attribute correspondences. This process can not be “pre-programmed†since the information to be accessed is heterogeneous. In this paper we present an architecture supporting dynamic integration. We first overview a tool, Semint, for automated semantic integration that helps database administrators generate attribute correspondences. We then introduce a novel framework for dynamic integration and a query language for multidatabase systems that uses Semint as part of a complete semantic integration service. Our framework supports dynamic integration as well as incremental integration. We show the advantages of our framework in an environment where full integration is not desired or complete knowledge of the databases to be integrated is unavailable.

Evaluation of attributed names

In this paper a new and original name evaluation method of attributed names is proposed and elaborated on. This method allows an attributed name to be presented in a non-hierarchical fashion and to be evaluated using a hierarchical approach. A three-level name model that supports attributed names for objects in a distributed system and the structure of naming contexts which bind attributed names onto objects are presented. The naming contexts are represented intuitively with a context-graph. To be able to meet the requirements generated from the name service semantics, a name evaluation model suitable for different name services, i.e. the conventional service, the selection service and the enquiry service has been developed. This model allows the name evaluation to be implemented efficiently. Moreover, to achieve the effectiveness and the efficiency in the implementation of the name evaluation, we have developed a set of algorithms, each of which is for a particular name service.

DIRECT: a query facility for multiple databases

The subject of this research project is the architecture and design of a multidatabase query facility. These databases contain structured data, typical for business applications. Problems addressed are: presenting a uniform interface for retrieving data from multiple databases, providing autonomy for the component databases, and defining an architecture for semantic services. DIRECT is a query facility for heterogeneous databases. The databases and their definitions can differ in their data models, names, types, and encoded values. Instead of creating a global schema, descriptions of different databases are allowed to coexist. A multidatabase query language provides a uniform interface for retrieving data from different databases. DIRECT has been exercised with operational databases that are part of an automated business system.

Resource integration using a large knowledge base in Carnot

A method for integrating separately developed information resources that overcomes incompatibilities in syntax and semantics and permits the resources to be accessed and modified coherently is described. The method provides logical connectivity among the information resources via a semantic service layer that automates the maintenance of data integrity and provides an approximation of global data integration across systems. This layer is a fundamental part of the Carnot architecture, which provides tools for interoperability across global enterprises. >