Incorporating an Element of Negotiation into a Service-Oriented Broker Application

The Software as a Service (SaaS) model is a service-based model in which a desired service is assembled, delivered and consumed on demand. The IBHIS broker is a ‘proof of concept’ demonstration of SaaS which is based on services that deliver data. IBHIS has addressed a number of challenges for several aspects of servicebased software, especially the concept of a ‘broker service’ and service negotiation that is only used in establishing end-user access authorizations. This thesis investigates and develops an extended form of service-based broker, called CAPTAIN (Care Planning Through Auction-based Information Negotiation). It extends the concepts and role of the broker as used in IBHIS, and in particular, it extends the service negotiation function in order to demonstrate a full range of service characteristics. CAPTAIN uses the idea of the integrated care plan from healthcare to provide a case study. A care planner acting on behalf of a patient uses the broker to negotiate with providers to produce the integrated care plan for the patient with the broker and the providers agreeing on the terms and conditions relating to the supply of the services. We have developed a ‘proof of concept’ service-oriented broker architecture for CAPTAIN that includes planning, negotiation and service-based software models to provide a flexible care planning system. The CAPTAIN application has been evaluated that focuses on three features: functions, data access and negotiation. The CAPTAIN broker performs as planned, to produce the integrated care plan. The providers’ data sources are accessed to read and write data records during and after service negotiation. The negotiation model permits the broker to interact with the providers to produce an adaptable plan, based on the client’s needs. The primary outcome is an extendable service-oriented broker architecture that can enable more scalable and flexible distributed information management by adding interaction with the data sources

Combinatorial Auction-based Mechanisms for Composite Web Service Selection

Composite service selection presents the opportunity for the rapid development of complex applications using existing web services. It refers to the problem of selecting a set of web services from a large pool of available candidates to logically compose them to achieve value-added composite services. The aim of service selection is to choose the best set of services based on the functional and non-functional (quality related) requirements of a composite service requester. The current service selection approaches mostly assume that web services are offered as single independent entities; there is no possibility for bundling. Moreover, the current research has mainly focused on solving the problem for a single composite service. There is a limited research to date on how the presence of multiple requests for composite services affects the performance of service selection approaches. Addressing these two aspects can significantly enhance the application of composite service selection approaches in the real-world. We develop new approaches for the composite web service selection problem by addressing both the bundling and multiple requests issues. In particular, we propose two mechanisms based on combinatorial auction models, where the provisioning of multiple services are auctioned simultaneously and service providers can bid to offer combinations of web services. We mapped these mechanisms to Integer Linear Programing models and conducted extensive simulations to evaluate them. The results of our experimentation show that bundling can lead to cost reductions compared to when services are offered independently. Moreover, the simultaneous consideration of a set of requests enhances the success rate of the mechanism in allocating services to requests. By considering all composite service requests at the same time, the mechanism achieves more homogenous prices which can be a determining factor for the service requester in choosing the best composite service selection mechanism to deploy

A Reinforcement Learning Quality of Service Negotiation Framework For IoT Middleware

The Internet of Things (IoT) ecosystem is characterised by heterogeneous devices dynamically interacting with each other to perform a specific task, often without human intervention. This interaction typically occurs in a service-oriented manner and is facilitated by an IoT middleware. The service provision paradigm enables the functionalities of IoT devices to be provided as IoT services to perform actuation tasks in critical-safety systems such as autonomous, connected vehicle system and industrial control systems. As IoT systems are increasingly deployed into an environment characterised by continuous changes and uncertainties, there have been growing concerns on how to resolve the Quality of Service (QoS) contentions between heterogeneous devices with conflicting preferences to guarantee the execution of mission-critical actuation tasks. With IoT devices with different QoS constraints as IoT service providers spontaneously interacts with IoT service consumers with varied QoS requirements, it becomes essential to find the best way to establish and manage the QoS agreement in the middleware as a compromise in the QoS could lead to negative consequences. This thesis presents a QoS negotiation framework, IoTQoSystem, for IoT service-oriented middleware. The QoS framework is underpinned by a negotiation process that is modelled as a Markov Decision Process (MDP). A model-based Reinforcement Learning negotiation strategy is proposed for generating an acceptable QoS solution in a dynamic, multilateral and multi-parameter scenarios. A microservice-oriented negotiation architecture is developed that combines negotiation, monitoring and forecasting to provide a self-managing mechanism for ensuring the successful execution of actuation tasks in an IoT environment. Using a case study, the developed QoS negotiation framework was evaluated using real-world data sets with different negotiation scenarios to illustrate its scalability, reliability and performance

An Architecture for Flexible Web Service QoS Negotiation

The web service selection phase is usually driven only by functional requirements. Non functional requirements, such as quality of service, should be negotiated by the service consumer and the service provider during service invocation in order to produce a contract to manage service provisioning and to monitor the actual fulfilment of negotiated SLAs. In this paper an automated approach to web service QoS negotiation is proposed; the negotiation is performed by a Negotiation Broker to which both the consumer and the service provider can notify their preferences on QoS attributes and negotiation strategies by specifying the value of a relatively small set of parameters. When consumers are unable to specify such parameters or do not trust the service provisioning platform, negotiation can also be automated only on the provider side, allowing the direct interaction of the service consumer with the broker. An architecture to support the above mentioned functionalities is also described

Uma proposta de arquitetura de resiliência computacional para infraestruturas baseadas em SOA de empresas virtuais

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia de Automação e Sistemas, Florianópolis, 2019Uma Empresa Virtual (EV) é um tipo de rede colaborativa de organizações na qual grupos de empresas se unem dinâmica, lógica e temporariamente para melhor atender a demandas de mercado. Atuando como se fossem uma única empresa, compartilham recursos, custos e riscos de um negócio, representando assim um proeminente modelo de sustentabilidade, especialmente para pequenas e médias empresas. Uma das pré-condições para atuar numa EV é que os sistemas computacionais dos seus membros interoperem para que os processos de negócio associados à EV possam ser executados sem problemas pelos mais diversos sistemas envolvidos. Esta tese explora um cenário onde todos os sistemas das empresas são implementados de uma forma que possam ser expostos como serviços de software numa perspectiva SOA (Service Oriented Architecture), serem invocados pelos processos de negócio da EV em questão e, ao mesmo tempo, possam ser compartilhados com os outros membros. Desta forma, quando uma EV é formada, um grande sistema distribuído baseado em serviços é dinamicamente criado. Dado que em uma EV novas empresas podem entrar e outras sair ao longo de sua existência, tal sistema não é estático, mas sim deve alterar sua composição, tanto em tempo de projeto, quanto em tempo de execução. Como cada empresa pode participar simultaneamente em mais do que uma EV, isso também significa que cada um dos seus serviços poderá estar envolvido ao mesmo tempo em inúmeras orquestrações, porém em diferentes contextos de negócio e requisitos de qualidade de serviço. Este sistema computacional (e seus inúmeros serviços) deve permanecer operacional ao longo de todo ciclo de vida da EV de forma a sustentar a execução dos processos e, assim, do negócio. Em um sistema como esse, largamente distribuído e com serviços implementados em diferentes tecnologias, várias falhas podem ocorrer. Esta tese propõe uma arquitetura computacional para um sistema de resiliência para esse cenário, fazendo com que o sistema como um todo se recupere diante das falhas e mantenha o nível de qualidade de serviço geral do negócio da EV. Após pesquisa na literatura, não foram encontrados trabalhos que cobrissem a área de intersecção entre resiliência, SOA e EV. Baseado no modelo de referência de computação autonômica MAPE-K, a arquitetura proposta é auto resiliente e foi concebida ela mesma como SOA; portanto distribuída, com baixo acoplamento e escalável. Além disso, seu projeto contempla as modernas visões de economia orientada a serviços, compreendendo ecossistemas de provedores de serviços de software. Para garantir a permanência da EV em operação, várias técnicas consolidadas de tolerância a falhas foram empregadas, combinadas e adaptadas ao cenário em questão, atuando tanto reativamente como proativamente, e respeitando os níveis de responsabilidade das camadas de negócio, TI e de infraestrutura computacional. Um robusto protótipo de software foi implementado como prova de conceito, onde se buscou utilizar o maior número possível de padrões abertos de TI. Ele foi avaliado experimentalmente em um cenário controlado de EV. Ao se aplicar indicadores de desempenho de referência, a arquitetura mostrou-se promissora, suportando a execução dos sistemas da EV na quase totalidade dos casos mesmo diante de inúmeras falhas. A implementação teve algumas simplificações e o desenho da arquitetura partiu de uma série de pressupostos. Ao final, conclusões finais do trabalho são apresentadas bem como um conjunto de trabalhos futuros é sugerido.Abstract: Virtual Enterprises (VE) is a type of collaborative networked organization in which groups of companies are dynamically, logically and temporally joined to better meet market demands. Acting as a single company, they share resources, costs and business risks, thus representing a prominent sustainability model, especially for small and medium-sized enterprises. One of the preconditions for operating as an EV is that the members? IT systems should interoperate in way the business processes associated with EV can be executed by the most diverse involved systems without problems. This thesis exploits a scenario where all company systems are implemented in way they can be exposed as software services in the SOA (Service Oriented Architecture) perspective, being invoked by the VE?s business processes and, at the same time, can be shared with the other members. In this way, when an EV is formed, a large distributed service-based system is dynamically created. Given that new companies can enter and other leave a VE during the general VE process, such system is not static, but rather can change its composition, both at design and run time. Yet, since given companies can participate in many EV simultaneously, this also means that their services can be involved in diverse orchestrations although in different business contexts and quality of services requirements. This computational system (and its many services) should remain operating throughout the VE?s life cycle in order to sustain the execution of the processes and thus of the business. In a system like this, widely distributed and with services implemented in different technologies, several failures can occur. This thesis proposes a resilience system computing architecture for this scenario, making the system able to recover from failures while maintaining the level of general service quality of the VE business. After a literature research, no works were found out that covered the intersection area of resilience, SOA and VE. Based on the MAPE-K autonomic computing reference model, the proposed architecture is self-resilient and was conceived as a SOA itself; therefore, it is distributed, loosely coupled and scalable. In addition, its design adopts the modern vision of service-oriented economy, comprising ecosystems of software service providers. In order to guarantee the VE operation, several fault tolerance techniques were used, combined and adapted to that scenario, acting both reactively and pro-actively, and respecting the responsibility levels of the business, IT and computing infrastructure layers. A robust software prototype was implemented as proof of concept, using as many open IT standards as possible. It was evaluated experimentally in a controlled VE scenario. After the application of reference performance indicators, the architecture showed to be promising, supporting the VE?s systems execution in almost all cases in the presence of numerous failures. The implementation has simplifications and the architecture design has adopted several assumptions. Conclusions are presented in the end, including suggestions for future work

Organic Service-Level Management in Service-Oriented Environments

Dynamic service-oriented environments (SOEs) are characterised by a large number of heterogeneous service components that are expected to support the business as a whole. The present work provides a negotiation-based approach to facilitate automated and multi-level service-level management in an SOE, where each component autonomously arranges its contribution to the whole operational goals. Evaluation experiments have shown an increased responsiveness and stability of an SOE in case of changes