An Event Based Model for Web Service Coordination

The promise of Web services is centered around standard and interoperable means for integrating loosely coupled Web based components that expose well-defined interfaces, while abstracting the implementation and platform specific details. The current and more mature core Web services standards SOAP, WSDL and UDDI provide a solid foundation to accomplish this. However, these specifications primarily enable development of simple Web services whereas the ultimate goal of Web services is to facilitate and automate business process collaborations both inside and outside enterprize boundaries. Useful business applications of Web services in B2B, B2C, and enterprize application integration environments will require the ability to compose complex and distributed Web services and the ability to formally describe the relationships between the constituent low-level services. This paper advocates an event-based approach for Web services coordination. We focused on reasoning about events to capture the semantics of complex Web service combinations. Then we present a formal language to specifying composite events for managing complex interactions amongst services, and detecting inconsistencies that may arise at run-time

Configurable composition and adaptive provisioning of web services

Web services composition has been an active research area over the last few years. However, the technology is still not mature yet and several research issues need to be addressed. In this paper, we describe the design of CCAP, a system that provides tools for adaptive service composition and provisioning. We introduce a composition model where service context and exceptions are configurable to accommodate needs of different users. This allows for reusability of a service in different contexts and achieves a level of adaptiveness and contextualization without recoding and recompiling of the overall composed services. The execution semantics of the adaptive composite service is provided by an event-driven model. This execution model is based on Linda Tuple Spaces and supports real-time and asynchronous communication between services. Three core services, coordination service, context service, and event service, are implemented to automatically schedule and execute the component services, and adapt to user configured exceptions and contexts at run time. The proposed system provides an efficient and flexible support for specifying, deploying, and accessing adaptive composite services. We demonstrate the benefits of our system by conducting usability and performance studies. © 2009 IEEE

Service-oriented control architecture for reconfigurable production systems

Evolvable and collaborative production systems are becoming an emergent paradigm towards flexibility and automatic re-configurability. The reconfiguration of those systems requires the existence of distributed and modular control components that interact in order to accomplish control activities. This paper focuses on service-oriented production systems, which behavior is regulated by the coordination of services that are provided and required by control components with different roles. Internally, these components are independent of the implementations, but an internal modular and event based structure is presented. Individual control and interaction is achieved by using embedded or inter-service control processes for which High-Level Petri Nets are proposed. Supporting the predefined control, decision support systems are used to provide conflict resolution and other decision-making functions

An adaptation of SERVQUAL for events evaluation: an environmental sustainability addon

The events sector is continuously growing, driven by economic development and increased spending on leisure. As events may generate a large amount of waste, an environmental impact assessment is increasingly important for any event. The importance and necessity of this has recently become more significant not only from an environmental preservation perspective, but also from a social responsibility perspective, and from a marketing and public relations perspective. This paper presents a study carried out with the objective of creating a model adapted from the ServQual to evaluate the quality of the service provided with events, complementing the model with an environmental sustainability add on. Based on an action-research approach, a model was built that was developed and applied to small events in a Brazilian municipality. As the main result of this work, this approach allowed to create a way to measure the event quality, considering the gaps between expectations and perceptions of the client, adapting the ServQual Model to an event-type service. Moreover, it allowed the inclusion of an environmental sustainability dimension to ServQual. This adaptation of the model introduced new managerial analysis and was considered relevant by event managers. This study extends the application of service management tools to the specific domain of events, building on the perspective that event management shares a great deal of characteristics of services.This work was partially supported by FCT—Fundação para a Ciência e Tecnologia within the R&D Units Project Scope UIDB/00319/2020, and by CAPES—Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Coordination of Superior Level Staff Improvement) within the Science without Borders Program Scop

Separating Agent-Functioning and Inter-Agent Coordination by Activated Modules: The DECOMAS Architecture

The embedding of self-organizing inter-agent processes in distributed software applications enables the decentralized coordination system elements, solely based on concerted, localized interactions. The separation and encapsulation of the activities that are conceptually related to the coordination, is a crucial concern for systematic development practices in order to prepare the reuse and systematic integration of coordination processes in software systems. Here, we discuss a programming model that is based on the externalization of processes prescriptions and their embedding in Multi-Agent Systems (MAS). One fundamental design concern for a corresponding execution middleware is the minimal-invasive augmentation of the activities that affect coordination. This design challenge is approached by the activation of agent modules. Modules are converted to software elements that reason about and modify their host agent. We discuss and formalize this extension within the context of a generic coordination architecture and exemplify the proposed programming model with the decentralized management of (web) service infrastructures

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

On Formal Consistency between Value and Coordination Models

In information systems (IS) engineering dierent techniques for modeling inter-organizational collaborations are applied. In particular, value models estimate the profitability for involved stakeholders, whereas coordination models are used to agree upon the inter-organizational processes before implementing them. During the execution of inter-organizational collaboration, in addition, event logs are collected by the individual organizations representing another view of the IS. The combination of the two models and the event log represent the IS and they should therefore be consistent, i.e., not contradict each other. Since these models are provided by dierent user groups during design time and the event log is collected during run-time consistency is not straight forward. Inconsistency occurs when models contain a conflicting description of the same information, i.e., there exists a conflicting overlap between the models. In this paper we introduce an abstraction of value models, coordination models and event logs which allows ensuring and maintaining alignment between models and event log. We demonstrate its use by outlining a proof of an inconsistency resolution result based on this abstraction. Thus, the introduction of abstractions allows to explore formal inter-model relations based on consistency

TeamWorker: An agent-based support system for mobile task execution

Traditional workflow management systems are considered insufficiently flexible to support autonomous job management via close team working. This paper proposes a multi-agent system approach to enhancing existing workflow management systems to enable team-based job management in the field of telecommunications service provision and maintenance. This paper adopts a component-based approach and explains how applications can be developed by customising the generic components provided by a multi-agent systems framework

Tropical Cyclone ENAWO - Post-Event Report

Tropical Cyclones (TCs) are among the most damaging events. They affect the population with three dangerous effects: strong wind, heavy rain and storm surge. JRC has developed a system used in Global Disaster Alert and Coordination System (GDACS) that includes the analysis of all these effects for every TC occurring worldwide to assess the overall impact. This document is the first POST-EVENT Report, which is a new type of report produced by the JRC after a major event aimed to report the real status of the impact that occurred, based on media reports, onsite analyses, and satellite images. The event analysed in this report is the intense TC ENAWO, that made landfall in north-eastern Madagascar on 7 March 2017, killing more than 80 people and causing extensive damage, especially in Sava and Analanjirofo regions. Authorities issued a "declaration of national emergency" and formally requested international assistance on 14 March. GDACS issued the first RED alert (for high winds) in Madagascar on 3 March. The Emergency Response Coordination Centre (ERCC) of DG ECHO activated ARISTOTLE on 5 March and the Copernicus Emergency Management Service (EMS) on 7 March. The responses of the alert and information systems are analysed and the results are compared with the damage reported by national authorities and satellite images analysis. In order to improve the current early warning system and impact estimations, JRC is implementing a new method to evaluate the areas potentially most affected by a TC, using new datasets and classifications. The results are also included in the report.JRC.E.1-Disaster Risk Managemen

CMD: A Multi-Channel Coordination Scheme for Emergency Message Dissemination in IEEE 1609.4

In the IEEE 1609.4 legacy standard for multi-channel communications in vehicular ad hoc networks(VANETs), the control channel (CCH) is dedicated to broadcast safety messages while the service channels (SCH's) are dedicated to transmit infotainment service content. However, the SCH can be used as an alternative to transmit high priority safety messages in the event that they are invoked during the service channel interval (SCHI). This implies that there is a need to transmit safety messages across multiple available utilized channels to ensure that all vehicles receive the safety message. Transmission across multiple SCH's using the legacy IEEE 1609.4 requires multiple channel switching and therefore introduces further end-to-end delays. Given that safety messaging is a life critical application, it is important that optimal end-to-end delay performance is derived in multi-channel VANET scenarios to ensure reliable safety message dissemination. To tackle this challenge, three primary contributions are in this article: first, a channel coordinator selection approach based on the least average separation distance (LAD) to the vehicles that expect to tune to other SCH's and operates during the control channel interval (CCHI) is proposed. Second, a model to determine the optimal time intervals in which CMD operates during the CCHI is proposed. Third, a contention back-off mechanism for safety message transmission during the SCHI is proposed. Computer simulations and mathematical analysis show that CMD performs better than the legacy IEEE 1609.4 and a selected state-of-the-art multi-channel message dissemination schemes in terms of end-to-end delay and packet reception ratio.Comment: 15 pages, 10 figures, 7 table