Richard Torbjørn Sanders

Service discovery and component reuse with semantic interfaces

Current trends in distributed computing and e-business processing suggest that many applications are evolving towards Service Oriented Computing (SOC) with technologies such as Web services. Services are autonomous platform-independent computational elements, and we observe an increasing need for core SOC technologies for dynamic discovery, selection, and composition of services. However, such technologies are often based on syntactic descriptions of the services and of their interfaces, which are insufficient to ensure that desired liveness properties are satisfied. In this paper, we propose an approach for the description, discovery, and selection of services based on role modeling and goal expressions that enables the definition of semantic interfaces and the evaluation of liveness properties. The same mechanisms also enable component reuse. We discuss how UML 2.0 can support the modeling of both the services and the desired properties. The approach is illustrated with telephony services.

Using UML 2.0 collaborations for compositional service specification

Collaborations and collaboration uses are features new to UML 2.0. They possess many properties that support rapid and compositional service engineering. The notion of collaboration corresponds well with the notion of a service, and it seems promising to use them for service specification. We present an approach where collaborations are used to specify services, and show how collaborations enable high level feature composition by means of collaboration uses. We also show how service goals can be combined with behavior descriptions of collaborations to form what we call semantic interfaces. Semantic interfaces can be used to ensure compatibility when binding roles to classes and when composing systems from components. Various ways to compose collaboration behaviors are outlined and illustrated with telephony services.

Modeling peer-to-peer service goals in UML

In this paper we present a method for describing Service Goals for peer-to-peer systems using UML 2. 0. We propose how to model services at a higher level than protocols and state machines, and how this modeling can relate to lower layers of abstraction. We show how this novel way of service specification can contribute to service validation and to dynamic discovery of peer-to-peer services.

A comprehensive engineering framework for guaranteeing component compatibility

Despite advances in software engineering methods and tools, understanding what software components do and ensuring that they work well together remains difficult. This is chiefly due to the lack of support for specifying component interfaces and software compositions formally. Due to these shortcomings, composed systems are subject to incompatibility errors, and software developers struggle to retrieve and understand relevant reusable entities. Constructs recently added to the Unified Modeling Language (UML) supported by validation tools can detect and solve behavioural incompatibility issues, while integrated support for characterisation using ontological techniques can describe what a component does. This paper presents a comprehensive software engineering framework that supports software composition at design time and runtime with compatibility guarantees. Our main contributions are (a) a model-driven development approach that combines UML modelling and ontology techniques for the specification of component properties, their validation and their transformation to code, (b) a middleware platform that supports component discovery, compatibility checking and deployment. Following the proposed approach gives benefits for software engineering, in particular in settings where multiple stakeholders are involved.

Describing component collaboration using goal sequences

Services are normally not performed by a single component, but result from the collaboration of several distributed components. Their precise specification and validation require complex models, where the intention of the service is easily lost in the detail. This paper exploits the concept of service goals that was earlier introduced to simplify service modeling. It describes the semantics of service goals, how to specify and how to use them. We show that so-called goal sequences can provide a designer-friendly, high-level description of the intention of the service, while maintaining simplicity, reusability and flexibility when composing from elementary services. By way of examples, we illustrate the difference between goal sequences and behavior descriptions. Finally we discuss issues related to the validation of goal sequences and their use at design time and runtime, for example in connection with service discovery.

CloudStore – Towards Scalability Benchmarking in Cloud Computing

Abstract This paper describes CloudStore, an open source application that lends itself to analyzing key characteristics of Cloud computing platforms. Based on an earlier standard from transaction processing, it represents a simplified version of a typical e-commerce application – an electronic book store. We detail how a deployment on a popular public cloud offering can be instrumented to gain insight into system characteristics such as capacity, scalability, elasticity and efficiency.

CloudStore — towards scalability, elasticity, and efficiency benchmarking and analysis in Cloud computing

Abstract This paper describes CloudStore, an open source application that lends itself to analyzing key characteristics of Cloud computing platforms. Based on an earlier standard from transaction processing, it represents a simplified version of a typical e-commerce application–an electronic book store. We detail how a deployment on a popular public cloud offering can be instrumented to gain insight into system characteristics such as capacity, scalability, elasticity and efficiency. Based on our insights, we create a CloudStore performance model, allowing to accurately predict such properties already at design time.

Modeling and Validating Service Choreography with Semantic Interfaces and Goals

Service choreography is a composition approach which has not yet received wide attention in SOA research. In this paper, we describe an approach for the modeling and validation of choreography based on so-called Semantic Interfaces and Goals. Our contributions include flexible modeling of choreography with formal semantics and solid validation techniques supported by tools. The approach is explained through an illustrating example.

End-user configuration of telco services

Proper handling of incoming calls depending on the location and availability of the callee is important both for the individual and for the organization in which they belong. The recent proliferation of smart phones can provide the end user with new graphical representations of relevant configurations, and open up for new ways of triggering notifications. This is demonstrated by the EasyMobile from Gintel, a prototype app for Android phones.

Service Composition for end-users: A tool for telephony services

This work presents a graphical tool for end-user service composition. The tool, EasyComposer, has been developed within the context of a research project addressing end-user service composition in ubiquitous service environments. The EasyComposer is a simple composition tool that the end user can use to compose telephony based services to handle primarily the end-users incoming calls. The paper presents also an example service composition.