An extensible architecture for run-time monitoring of conversational web services

Trust in Web services will be greatly enhanced if these are subject to run-time verification, even if they were previously tested, since their context of execution is subject to continuous change; and services may also be upgraded without notifying their consumers in advance. Conversational Web services introduce added complexity when it comes to run-time verification, since they follow a conversation protocol and they have a state bound to the session of each consumer accessing them. Furthermore, conversational Web services have different policies on how they maintain their state. Access to states can be private or shared; and states may be transient or persistent. These differences must be taken into account when building a scalable architecture for run-time verification through monitoring. This paper, building on a previously proposed theoretical framework for run-time verification of conversational Web services, presents the design, implementation and validation of a novel run-time monitoring architecture for conversational services, which aims to provide a holistic monitoring framework enabling the integration of different verification tools. The architecture is validated by running a sequence of test scenarios, based on a realistic example. The experimental results revealed that the monitoring activities have a tolerable overhead on the operation of a Web service

Brokerage for Quality Assurance and Optimisation of Cloud Services: An Analysis of Key Requirements

As the number of cloud service providers grows and the requirements of cloud service consumers become more complex, the latter will come to depend more and more on the intermediation services of cloud service brokers. Continuous quality assurance and optimisation of services is becoming a mission-critical objective that many consumers will find difficult to address without help from cloud service intermediaries. The Broker@Cloud project envisages a software framework that will make it easier for cloud service intermediaries to address this need, and this paper provides an analysis of key requirements for this framework. We discuss the methodology that we followed to capture these requirements, which involved defining a conceptual service lifecycle model, carrying out a series of Design Thinking workshops, and formalising requirements based on an agile requirements information model. Then, we present the key requirements identified through this process in the form of summarised results

SLAs for cross-layer adaptation and monitoring of service-based applications

Cross-layer adaptation and monitoring (CLAM) is an approach to the run-time quality assurance of service-based applications (SBAs). The aim of CLAM is to monitor the different layers of an SBA and correlate the monitoring results, such that in the event that a problem occurs an effective adaptation strategy is inferred for enacting a coordinated adaptation across all layers of the SBA. An important aspect of CLAM is the definition of the appropriate Service-Level Agreements (SLAs) for third party services utilised in the different layers of the SBAs. In this paper, we present insights into how to define SLAs for CLAM, by analysing SBAs in order to differentiate the third party business, software and infrastructure services utilised by the SBA. As a case study, we apply the analytical approach to an existing platform-as-a-service framework, which has been developed as an SBA and could benefit from CLAM. The analysis reveals the different third party services and their characteristics, as a precursor to defining SLAs. The case study successfully demonstrates how distinct SLAs for business, software and infrastructure services may be applied respectively in the BPM, SCC and SI layers of an SBA, to provide a flexible monitoring and adaptation response across layers

Advanced service brokerage capabilities as the catalyst for future cloud service ecosystems.

Market analysts have foreseen the emergence of cloud brokers in the mediation of cloud services. But rather than focus on current kinds of intermediary role, it is more constructive to consider the kinds of brokerage capability that could be offered in the future, which go far beyond the integration, aggregation and customization services available today. This paper identifies advanced capabilities for cloud service governance, quality assurance and optimization that will be critical in catalyzing the emergence of cloud service ecosystems, environments in which all parties will find their symbiotic niches. It shows the path whereby a platform provider could evolve to become the hub of a cloud service ecosystem, through gradually taking on more of these advanced brokerage capabilities. The paper provides an overview of work conducted by the EU FP7 Broker@Cloud project towards realizing these advanced brokerage capabilities

Emerging horizons for industrial applications of predatory bacteria

26 p.-4 fig.-2 tab. The Ecology of Predation at the Microscale pp 173-194This chapter reviews the potential of the predatory bacteria Bdellovibrio bacteriovorus, an obligate predator of other gram-negative bacteria, as a biotechnological tool. Due to the unique lifestyle and the different applications, predatory bacteria have awakened interest to be developed as a lytic tool. The lack of physiological and metabolic information makes difficult this development. However, in the last years, different approaches have been described in order to understand the physiology, morphology, and metabolism of the predators, as well as the population dynamics of the prey-predator interactions. Besides its potential of “living antibiotic”, predatory bacteria have been proposed as a biocontrol agent in the food industry or aquaculture. A recent work using B. bacteriovorus as a biological lytic tool for the recovery of intracellular bioproducts highlighted the potential use of predators in industrial bioprocesses. The bottlenecks of using other Bdellovibrio and like organisms (BALOs) have been also considered and discussed during this chapter.This work was supported by the European Union’s Horizon 2020 Research and Innovation Programme, grant agreement no. 760994-2 (ENGICOIN), the Spanish Ministry of Science, Innovation and Universities (BIO2017-83448-R) and the Community of Madrid (P2018/ NMT4389).Peer reviewe