Sam Guinea

Sam Guinea
Politecnico di Milano | Polimi · Department of Electronics, Information, and Bioengineering

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75
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2,427
Citations

Publications

Publications (75)
Article
Full-text available
Technologies such as mobile, edge, and cloud computing have the potential to form a computing continuum for new, disruptive applications. At runtime, applications can choose to execute parts of their logic on different infrastructures that constitute the continuum, with the goal of minimizing latency and battery consumption and maximizing availabil...
Article
[Context] Complex and heterogeneous software systems need to be monitored as their full behavior often only emerges at runtime, e.g., when interacting with other systems or the environment. Software monitoring approaches observe and check properties or quality attributes of software systems during operation. Such approaches have been developed in d...
Conference Paper
This paper presents MAGNET, a novel middleware infrastructure that exploits Wi-Fi Direct to provide a reliable and stable communication means for large numbers of mobile devices. This self-organizing middleware abstracts the multi-hop communication process by autonomously maintaining connectivity among devices. MAGNET also provides a discovery mech...
Article
The full behavior of complex software systems often only emerges during operation. They thus need to be monitored at run time to check that they adhere to their requirements. Diverse runtime monitoring approaches have been developed in various domains and for different purposes. Their sheer number and heterogeneity, however, make it hard to find th...
Conference Paper
Modern Web applications exploit Cloud infrastructures to scale their resources and cope with sudden changes in the workload. While the state of practice is to focus on dynamically adding and removing virtual machines, we advocate that there are strong benefits in containerizing the applications and in scaling the containers. In this paper we presen...
Conference Paper
This paper describes WiDiSi, a research-oriented prototype simulator for Wi-Fi Direct networks. WiDiSi is provided as an extension of PeerSim, a widely-used, open-source simulation framework for large-scale peer to peer networks. WiDiSi's main goal is to allow Android Wi-Fi direct applications to be easily tested in large-scale dynamic scenarios. I...
Conference Paper
Smart interconnected devices are changing our lives and are turning conventional spaces into smart ones. Physical proximity, a key enabler of social interactions in the old days is not exploited by smart solutions, where the social dimension is always managed through the Internet. This paper aims to blend the two forces and proposes the idea of soc...
Conference Paper
Steering modern Internet applications in the Cloud, given a set of functional and non-functional requirements, is a complex task. System maintainers need to have a holistic view of the application; they need to understand the intricate horizontal and vertical dependencies that exist between the infrastructure, platform, and software constituents. I...
Article
In this paper, we focus on the reliability and availability analysis of Web service (WS) compositions, orchestrated via the Business Process Execution Language (BPEL). Starting from the failure profiles of the services being composed, which take into account multiple possible failure modes, latent errors, and propagation effects, and from a BPEL pr...
Conference Paper
Service-based business processes must evolve to remain aligned with their goals, with zero downtime to guarantee business continuity. A new version of a service should be adopted as soon as it becomes available to let clients benefit from the updated functionality and/or improved quality of service. In practice, however, existing services may be in...
Conference Paper
This paper describes SeSaMe, an RDF-enriched self-adaptive middleware for highly dynamic and autonomic complex systems. Semantic technologies make components of a system mutually interoperable and enable them to exchange information even when they are developed and deployed on different platforms. SeSaMe uses semantics to achieve dynamic component...
Chapter
Cloud-based systems are built and delivered using multi-level architectures, which may compose third-party services at the application level as well as at lower levels, such as the platform and the infrastructure ones. With this architectural style, the ability to automatically perform management operations, possibly in a cross-level way, is becomi...
Article
XML has become a widespread format for data exchange over the Internet. The current state of the art in querying XML data is represented by XPath and XQuery, both of which define binary predicates. In this paper, we advocate that binary selection can at times be restrictive due to very nature of XML, and to the uses that are made of it. We therefor...
Conference Paper
Easy access to communication means and mobile devices are fostering the birth of systems that need to scale to high numbers of peers, adapt to high churn rates, and be performant and available even when the underlying network infrastructures are unreliable. A middleware that provides dynamic overlay management can support these needs, by providing...
Conference Paper
Due to the growing pervasiveness of the service paradigm, modern systems are now often built as software as a service, and tend to exploit underlying platforms and virtualized resources also provided as services. Managing such systems requires that we be aware of the behaviors of all the different layers, and of the strong dependencies that exist b...
Conference Paper
Full-text available
Smart spaces are inherently complex and dynamic systems, where diverse devices, sensors, actuators and computational elements need to interact with one another. A middleware infrastructure can provide suitable abstractions that simplify the task, and allow designers to ignore the details of the underlying elements. Unfortunately, however, existing...
Chapter
Distributed pervasive systems have been employed in a wide spectrum of applications, from environmental monitoring to smart transportation, to emergency response. In all these applications high volumes of typically volatile software components need to coordinate and collaborate to achieve a common goal, given a defined set of constraints. In our A-...
Article
An operational example of controls in a smart home demonstrates the potential of a solution that combines the Common Variability Language and a dynamic extension of the Business Process Execution Language to address the need to manage software system variability at runtime.
Conference Paper
Modern and evolving domains such as ambient intelligence, context-aware applications, and pervasive computing require that software systems be able to cope with unprecedented degrees of runtime variability. This demands that software systems be flexible, and easily adaptable in the wake of change. Providing such flexibility is a multi-faceted chall...
Article
Distributed pervasive systems have been employed in a wide spectrum of applications, from environmental monitoring, to emergency response. These systems have very strong coordination requirements and are hard to design. Their development becomes even more complex if we consider that they need to be able to adapt to the frequent changes that can occ...
Article
The service-oriented computing paradigm has been widely adopted in enterprises as a means to implement distributed computing solutions. These solutions are realized as service-based applications (SBAs), by integrating heterogeneous software services, usually developed, controlled and owned by different organizations. Given the availability of mecha...
Article
Full-text available
Distributed systems comprise a significant number of entities that must be properly coordinated to reach a goal. These systems present high turnover of elements, and demand for solutions that keep their coordination as decentralized as possible to avoid bottlenecks. The paper discusses why it is important to address these characteristics from a sys...
Article
Service compositions suffer changes in their partner services. Even if the composition does not change, its behavior may evolve over time and become incorrect. Such changes cannot be fully foreseen through prerelease validation, but impose a shift in the quality assessment activities. Provided functionality and quality of service must be continuous...
Conference Paper
Modern software systems challenge engineers with new critical requirements. Software must adapt effectively and efficiently with respect to the environment in which it is deployed. In this paper we introduce A-3: a framework for engineering distributed, component-based systems that facilitates the coordination of its components and the implementati...
Conference Paper
Full-text available
Service-basedapplicationshavebecomemoreandmoremulti- layered in nature, as we tend to build software as a service on top of in- frastructure as a service. Most existing SOA monitoring and adaptation techniques address layer-specific issues. These techniques, if used in iso- lation, cannot deal with real-world domains, where changes in one layer oft...
Chapter
Highly dynamic systems, such as those built using the Service-Oriented Architectures style, are built under an open-world assumption [3], meaning the system’s functionality and quality of service are determined by the set of services with which it interacts, and this set can evolve in many ways. Designers need to be sure evolutions will not lead to...
Article
Service-oriented systems live in an open world, one in which their functionality and quality of service depend on how the services they interact with evolve. System adaptation has been indicated as a way to cope with the evolution these partner services may have. When a partner does not behave as expected, in an adaptable system we can substitute i...
Conference Paper
Full-text available
Mashlight is a lightweight service composition framework for creating process mashups out of Web 2.0 widgets. Widgets represent a simple means to access heterogenous services on the web that non-technical users can easily comprehend. The framework provides a well-defined conceptual model that defines both the notion of composable widget, and how to...
Conference Paper
Mashlight is a framework for creating process mashups out of Web 2.0 widgets. In our demo we show how Mashlight can be used to simplify patient management in a hospital. We illustrate the design-time tools for creating mashups, a desktop execution environment, and mobile environments for iPhones and Android smartphones.
Conference Paper
Full-text available
Applications are increasingly composed of remote services provided by independent parties. This distributed ownership makes it problematic to measure and control quality of service indicators. Management activities must become an integral part of the system's development process, from requirements elicitation, where users identify the quality dimen...
Article
Service-oriented systems' distributed ownership has led to an increasing focus on runtime management solutions. Service-oriented systems can change greatly after deployment, hampering their quality and reliability. Their service bindings can change, and providers can modify the internals of their services. Monitoring is critical for these systems t...
Article
Full-text available
Today the current state of the art in querying XML data is represented by XPath and XQuery, both of which rely on Boolean conditions for node selection. Boolean selection is too restrictive when users do not use or even know the data structure precisely, e.g. when queries are written based on a summary rather than on a schema. In this paper we desc...
Conference Paper
In the literature, there exist several approaches for monitoring the execution of BPEL processes. They concentrate on different properties, adopt different languages, work at different levels of abstraction, and assume different perspectives. Even if the field is rather new, we do not think that this diversity is a limitation of current solutions;...
Conference Paper
Full-text available
Service compositions leverage remote services to deliver added-value distributed applications. Since services are administered and run by independent parties, the governance of service compositions is intrinsically decentralized and services may evolve independently over time. In this context, pre-deployment verification can only provide limited gu...
Conference Paper
Full-text available
The wide diffusion of reliable Internet is pushing two key novelties in the conception of modern software applications: the software as a service paradigm and the idea of the Internet of Things. Traditionally, services and things have been considered as separate entities, even addressing different needs and application domains. In contrast, we feel...
Article
Full-text available
Recently, Web 2.0 has brought a storm on web applica-tion development. In particular, mashups have greatly en-hanced user creativity across the web, allowing end-users to rapidly combine information from diverse sources, and in-tegrate them into "new" goal-oriented applications. In the meantime, widgets (also built with Web 2.0 technology) have als...
Conference Paper
In this paper, we compare and integrate Dynamo and ASTRO, two previous approaches of the authors for run-time monitoring of BPEL orchestrations. A key element of the proposed integrated framework is the capability to cover a wide range of features, including the detection of complex behavioural patterns, the possibility to measure boolean, numeric...
Conference Paper
In the past few years many supervision techniques were developed to provide reliable business processes and guarantee the established SLAs. Since none of them provided a definitive solution, the paper proposes a new composable approach, where a single framework provides the glue for different probing, analysis, and recovery capabilities. The paper...
Conference Paper
Web services have proven to be a viable solution for interoperability issues. Since end users do not buy services, but only interact with them remotely, such complex systems end up having a distributed ownership, meaning different parts of a system can evolve independently. This has brought researchers to concentrate on run-time management issues s...
Article
Full-text available
Modern software systems are challenging challenge software engineers since they must adapt effectively and efficiently with respect to the environment in which they are deployed. To this end, the paper outlines an architecture, supported by special-purpose languages and aspect oriented techniques, for the design of component-based of distributed se...
Conference Paper
Full-text available
The distributed nature of BPEL processes, the absence of a single stakeholder, the fact that partner services can dynamically change their functionality and/or QoS, and the fact we can define abstract processes and look for actual services at run-time, preclude design-time validation of such systems. We cannot assume that the cooperation between th...
Article
With the worldwide adoption of the Internet as a ubiquitous platform for exchanging information, new opportunities are available for sharing educational experiences and material. Thousands of institutes worldwide offer access to courses, lessons, seminars, and exercises, typically stored in repositories and offered to users under a variety of forma...
Article
Full-text available
Web services support software architectures that can evolve dynamically. In particular, in this paper the focus is on architectures where services are composed (orchestrated) through a workflow described in the business process execution language (BPEL). It is assumed that the resulting composite service refers to external services through assertio...
Conference Paper
Full-text available
Web service based applications are expected to live in dynamically evolving settings. At run-time, services may undergo changes that could modify their expected behavior. Because of such intrinsic dynamic nature, applications should be designed by adhering to the principles of design- by-contract. Run-time monitoring is needed to check that the con...
Conference Paper
Full-text available
Dynamo augments current BPEL technology with self-healing capabilities. Dedicated supervision rules allow the designer to set the amount of checks that must be performed at runtime and how the BPEL process must react whether anomalies arise. The technological underpinnings come from assertion languages and rule-based systems. The implementation exp...
Conference Paper
Full-text available
The execution of business processes with BPEL relies on external Web services, which are not necessarily managed by the process owner. This implies the need to constantly verify the correctness of the interactions between the involved parties. This paper proposes a design process model for the definition of supervised processes, in which supervisio...
Chapter
Service-oriented architectures are emerging as a solution to integrate components in highly dynamic and evolving contexts. The discovery phase supports flexible binding regimes among components. Bindings can take place either at deployment time or at run-time. Due to of dynamism, however, bindings can fail. The main faults of service-oriented syste...
Article
The basic paradigm of service-oriented architectures—publication, discovery, and use—can be interpreted in different ways. Current technologies assume a static and rigid approach: UDDI was conceived with the idea of a centralized repository for service publication and BPEL only supports design–time bindings between the orchestrated workflow and the...
Conference Paper
Full-text available
Web services are becoming progressively popular in the building of both inter- and intra-enterprise business processes. These processes are composed from existing Web services based on defined requirements. In collecting together the services for such a composition, developers can employ languages and standards for the Web that facilitate the autom...
Conference Paper
Full-text available
Service-Oriented Architectures are emerging as a promising solution to the problem of developing distributed and evolvable applications that live in an open world. We contend that developing these applications not only requires adopting a new architectural style, but more generally requires re-thinking the whole life-cycle of an application, from d...
Conference Paper
Full-text available
Many emerging domains such as ambient intelligence, context-aware applications, and pervasive computing are embracing the assumption that their software applications will be deployed in an open-world. By adopting the Service Oriented Architecture paradigm, and in particular its Web service based implementation, they are capable of leveraging compon...
Article
Full-text available
Modern software architectures are increasingly dynamic. Among them, Service-Oriented Architectures (SOAs) are becoming a dominant paradigm. SOAs allow components to be exported as services for external use. Service descriptions (which include functional and non-functional properties) are published by service providers and are later discovered by po...
Article
Research report of the ProLearn Network of Excellence (IST 507310), Deliverable 4.6
Conference Paper
Full-text available
XML has become a widespread format for data exchange over the Internet. The current state of the art in querying XML data is represented by XPath and XQuery, both of which define binary predicates. In this paper, we advocate that binary selection can at times be restrictive due to very nature of XML, and to the uses that are made of it. We therefor...
Conference Paper
This paper studies dependability in the context of service-based business processes, and proposes a dynamic technique for ensuring dependability requirements are met. On one hand, business processes are modeled using BPMN, which provides stakeholders with a suitable level of abstraction. On the other, we provide Dynamo, a run-time business process...
Conference Paper
Full-text available
This tutorial introduces dynamic web services as a solution to cope with the dynamism and flexibility required by many modern software systems. Current technologies (WSDL, WS-BPEL, etc.) have proven insufficient in addressing these issues; however, they remain a good starting point for the analysis of the current situation and for building for the...
Conference Paper
Full-text available
Dynamo advocates that pre-deployment validation and testing are in- trinsically inadequate for tackling the ephemeral and rapi dly changing context in which service oriented applications are deployed. Validation must be shifted to run-time and continuous monitoring must be introduced. We propose a simple ar- chitecture that, through specific and si...
Conference Paper
The service-oriented approach is becoming more and more popular to integrate highly heterogeneous systems. Service-oriented architectures (SoAs) define a new flexible coordination paradigm for integrating components (services) in unstable and evolving contexts, where the high degree of flexibility and dynamism requires that available functionality...
Conference Paper
Full-text available
SOAs (service oriented architectures) are becoming a new paradigm for flexible coordination between business partners within continuously evolving and heterogeneous environments. In these environments, the set of available services with which to do business changes constantly in number and type, hindering the degree of trustworthiness. In this rese...
Conference Paper
Full-text available
The intrinsic flexibility and dynamism of service-centric applications preclude their pre-release validation and demand for suitable probes to monitor their behavior at run-time. Probes must be suitably activated and deactivated according to the context in which the application is executed, but also according to the confidence we get on its quality...
Conference Paper
Full-text available
The paper presents a monitoring framework for WS-BPEL processes. It proposes WS-CoL (Web Service Constraint Language) as a domain-inde- pendent language, compliant with the WS-Policy framework, for specifying user requirements (constraints) on the execution of Web service compositions. WS- Policy and WS-CoL provide a uniform framework to accommodat...
Conference Paper
Full-text available
This tutorial introduces self-healing web services as a so- lution to cope with the dynamism and flexibility required by many modern software systems. Current technologies (WSDL, WS-BPEL, etc.) have proven insucient in ad- dressing these issues; however, they remain a good starting point for the analysis of the current situation and for build- ing...
Article
Full-text available
Research report of the ProLearn Network of Excellence (IST 507310), Deliverable 1.1
Conference Paper
Full-text available
The paper discusses the advantages of Virtual Campus, a platform integrating authoring, fruition and validation modules, where flexibility and personalization of the whole system are main goals. To ease the authoring activities, Virtual Campus leverages both the reusability of existing courses - while building new ones - and a customization process...
Conference Paper
Full-text available
Service-based approaches are widely used to integrate heterogenous systems. Web services allow for the definition of highly dynamic systems where components (services) can be discovered and QoS parameters negotiated at run-time. This justifies the need for monitoring service compositions at run-time. Research on this issue, however, is still in its...
Article
Full-text available
Service-oriented architectures are emerging as a solution to integrate components in unstable and evolving contexts. The discovery phase supports flex-ible and dynamic component bindings. Bindings can occur either at deployment time or at run-time. Because of dynamicity, however, bindings can fail. The paper identifies and classifies the main fault...

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