Maciej Zaremba

Semantically-enabled Service Oriented Architecture : Concepts, Technology and Application

Semantically enabled service-oriented architecture focused on principles of service orientation, semantic modeling, intelligent and automated integration defines grounds for a cutting-edge technology which enables new means to integration of services, more adaptive to changes in business requirements which occur over systems’ lifetime. We define the architecture starting from a global perspective and through Web service modeling ontology as its semantic service model we narrow down to its services, processes and technology we use for the reference implementation. On a B2B integration scenario we demonstrate several aspects of the architecture and further describe the evaluation of the implementation according to a community-agreed standard evaluation methodology for semantic-based systems.

WSMO-Lite: lightweight semantic descriptions for services on the web

The current Web service technology brought a new potential to the Web of services. However, the success of Web services still depends on resolving three fundamental challenges, namely search, integration and mediation. In this paper we define an extended Web service stack enabling total or partial automation of web service provisioning process. With the goal of a maximal Web standards compliance, we describe various types of service semantics, use RDF Schema (RDFS) to define a pragmatic meaning for those descriptions, and use Semantic Annotations for WSDL and XML Schema (SAWSDL) to define a place for a semantic description in a Web service. We elaborate on the existing SAWSDL specifications and define precise rules for semantic annotations of Web services.

WSMX: a semantic service oriented middleware for b2b integration

In this paper we present a B2B integration scenario building on the principles of Semantic Web services. For this scenario we show the benefits of semantic descriptions used within the integration process to enable conversation between systems with data and process mediation of services. We illustrate our approach on the WSMX – a middleware platform built specifically to enact semantic service oriented architectures.

Dynamic Service Discovery Through Meta-interactions with Service Providers

Dynamic discovery based on semantic description of services is an essential aspect of the Semantic Web services integration process. Since not all data required for service discovery can always be included in service descriptions, some data needs to be obtained during run-time. In this paper we define a model for service interface allowing required data to be fetched from the service provider during discovery process. We also provide a specification of such interface for WSMO and demonstrate the model on a case scenario from the SWS Challenge implemented using WSMX --- a middleware platform built specifically to enact semantic service oriented architectures.

Personalised graph-based selection of web APIs

Modelling and understanding various contexts of users is important to enable personalised selection of Web APIs in directories such as Programmable Web. Currently, relationships between users and Web APIs are not clearly understood and utilized by existing selection approaches. In this paper, we present a semantic model of a Web API directory graph that captures relationships such as Web APIs, mashups, developers, and categories. We describe a novel configurable graph-based method for selection of Web APIs with personalised and temporal aspects. The method allows users to get more control over their preferences and recommended Web APIs while they can exploit information about their social links and preferences. We evaluate the method on a real-world dataset from ProgrammableWeb.com, and show that it provides more contextualised results than currently available popularity-based rankings.

Semantic SOA to Promote Integration of Heterogeneous B2B Services

Modeling the semantics of business services and their corresponding messages using ontologies enables flexible integration that is more adaptive to business-driven change. In this paper we demonstrate our approach building upon an established semantic Web service framework (WSMX) to facilitate a conversation between heterogeneous services that support both the RosettaNet standard and proprietary information models.

Towards Optimized Data Fetching for Service Discovery

The advent of Service Oriented Architecture makes services the most flexible, platform-independent choice for exposing and integrating business functionality across a network. However, the lack of service discovery mechanisms, that go beyond simple keyword search to enable automated late-binding of service requesters to providers, remains a major problem. Realistic late-binding involves matchmaking of client requests with service descriptions, based on frequently changing fine-grained client requests, and dynamically changing service functionality. The intricacies of service functionality cannot be specified by generic static descriptions since the functionality offered by the service may depend on the client at hand, their specific request and the services current capabilities. In this paper, we propose a semantic framework supporting dynamic data fetching from services during the discovery phase on service instance level entailing a communication overhead which we aim to minimize.

Ensuring Customised Transactional Reliability of Composite Services

Web services are defined independently of any execution context. Due to their inherent autonomy and heterogeneity, it is difficult to examine the behaviour of composite services, especially in case of failures. This paper is interested in ensuring composite services reliability. Reliable composition is defined as a composition where all instance executions are correct from a transactional and business point of view. In this paper, the authors propose a transactional approach for ensuring reliable Web service compositions. The approach integrates the expressivity power of workflow models and the reliability of Advanced Transactional Models ATM. This method offers flexibility for designers to specify their requirements in terms of control structure, using workflow patterns, and execution correctness. Contrary to ATM, the authors start from the designers specifications to define the appropriate transactional mechanisms that ensure correct executions according to their requirements.

Discovery of Optimized Web Service Configurations Using a Hybrid Semantic and Statistical Approach

We present a Semantic Optimized Service Discovery (SemOSD) approach capable of handling Web service search requests on a fine-grained level of detail where we augment semantic service descriptions with statistically built predictor functions. Our approach combines ontologies and mathematical functions built using statistical regression over previous Web service interactions. In the search requests we allow for arbitrary, independent and dependent constraints and user preferences expressed using objective functions. Our approach maps to standard Operational Research global optimization problem where algorithms of Simulated Annealing and Differential Evolution are used. It is capable of finding the optimal combination of service input and output parameters (a configuration) to a user request with rich preferences. Our approach is applied to an international package shipment scenario where real (Web) services are used and mined to create price prediction models. We show that the chosen regression method provides price prediction models of high accuracy and our approach supports expressive and complex search requests.

Modelling Capabilities as Attribute-Featured Entities

The concept of capability is a fundamental element not only for Service Oriented Architecture but also for Enterprise Information Systems. This concepts denotes what an action (i.e., a service, a program, a business process, etc.) can do from a functional perspective. Despite its importance, current approaches do not model it properly: either they confuse it with an annotated invocation interface or do not go beyond the classical IOPE paradigm which, from an end user perspective, does not have an intuitive description of what is the capability being modeled. In this paper, we present a conceptual model as an RDF-schema for describing capabilities as attribute-featured entities which is more user friendly. Actually, we consider a capability as an action verb and a set of domain specific attributes that relates to an exact business meaning. This way, we are able to represent capabilities at several levels of abstraction from the most abstract one with just an action verb to the most concrete one that corresponds to the exact need of an end user which is not possible with current capability modelling approaches. We are also able to interlink capabilities for creating a hierarchical structure that allows for improving the discovery process. Our meta model is based on RDF and makes use of Linked Data to define capability attributes as well as their values.