Improving the Scalability of DPWS-Based Networked Infrastructures

The Devices Profile for Web Services (DPWS) specification enables seamless discovery, configuration, and interoperability of networked devices in various settings, ranging from home automation and multimedia to manufacturing equipment and data centers. Unfortunately, the sheer simplicity of event notification mechanisms that makes it fit for resource-constrained devices, makes it hard to scale to large infrastructures with more stringent dependability requirements, ironically, where self-configuration would be most useful. In this report, we address this challenge with a proposal to integrate gossip-based dissemination in DPWS, thus maintaining compatibility with original assumptions of the specification, and avoiding a centralized configuration server or custom black-box middleware components. In detail, we show how our approach provides an evolutionary and non-intrusive solution to the scalability limitations of DPWS and experimentally evaluate it with an implementation based on the the Web Services for Devices (WS4D) Java Multi Edition DPWS Stack (JMEDS).Comment: 28 pages, Technical Repor

Pattern-based software architecture for service-oriented software systems

Service-oriented architecture is a recent conceptual framework for service-oriented software platforms. Architectures are of great importance for the evolution of software systems. We present a modelling and transformation technique for service-centric distributed software systems. Architectural configurations, expressed through hierarchical architectural patterns, form the core of a specification and transformation technique. Patterns on different levels of abstraction form transformation invariants that structure and constrain the transformation process. We explore the role that patterns can play in architecture transformations in terms of functional properties, but also non-functional quality aspects

Service validity and service reliability of search, experience and credence services: A scenario study

The purpose of this research is to add to our understanding of the antecedents of customer satisfaction by examining the effects of service reliability (Is the service “correctly” produced?) and service validity (Is the “correct” service produced?) of search, experience and credence services.\ud Design/methodology/approach – Service validity and service reliability were manipulated in scenarios describing service encounters with different types of services. Customer satisfaction was measured using questionnaires.\ud Findings – Service validity and service reliability independently affect customer satisfaction with search services. For experience services, service validity and service reliability are necessary conditions for customer satisfaction. For credence services, no effects of service validity were found but the effects of service reliability on customers' satisfaction were profound.\ud Research limitations/implications – Scenarios provided a useful method to investigate customer evaluation of different types of service situations. A limitation of this method was that the participants were not observed in a real service situation but had to give their opinion on hypothetical scenarios.\ud Practical implications – For search and credence services, it is possible to compensate low service validity by providing a highly reliable service. However, managers of experience services should be aware that little can be gained when either service validity or service reliability is faulty.\ud Originality/value – The present study provides empirical data on the effects of service reliability and the thus far neglected effects of service validity and integrates these (new) concepts in the model of information verification

A language for information commerce processes

Automatizing information commerce requires languages to represent the typical information commerce processes. Existing languages and standards cover either only very specific types of business models or are too general to capture in a concise way the specific properties of information commerce processes. We introduce a language that is specifically designed for information commerce. It can be directly used for the implementation of the processes and communication required in information commerce. It allows to cover existing business models that are known either from standard proposals or existing information commerce applications on the Internet. The language has a concise logical semantics. In this paper we present the language concepts and an implementation architecture