Stefano Monti

Integrating Web services and mobile agent systems

Middleware supports based on mobile agents (MAs) have recently emerged with the goal of allowing application developers to easily manage and control the properties and behaviors of mobile systems, especially in novel wireless and ubiquitous scenarios. Several MA systems have grown independently with no widely recognized standardization and still lack functions for easy integration. The primary consequence is that one MA platform tends to offer middleware facilities scarcely compatible with other MA systems. Moreover, MA tools are sometimes difficult to employ by common users who have to overcome a significant knowledge gap before properly exploiting MA-specific functions. The paper proposes a solution to open up the usage of MA systems via the bridge of the emerging Web services (WS) standard technology to achieve interoperability. We have developed an integration infrastructure, called WSMI, with the twofold goal of exporting the MA functions with a WS interface and of simplifying the access to legacy WS components from any MA system. This promotes the uniform access to different MA system functions, independently of the specific MA implementation. We have thoroughly evaluated the WSMI prototype performance, also by comparing the WSMI integration functions with similar non-WS-based facilities: the increased dynamicity and openness of our integration infrastructure have demonstrated to largely counterbalance the overhead introduced by WS adoption.

Dynamic reconfiguration of middleware for ubiquitous computing

Ubiquitous Computing scenarios call for middleware support solutions able to cope with changes in environmental conditions and user requirements. Changes obviously greatly impact on the application logic the middleware is able to carry out (content/service adaptation, multichannel content delivery, mobility management and so on), but also on the non-functional support logic middleware exploits to enforce the application logic itself (e.g., naming, persistence, communication infrastructures). This work proposes a novel middleware for Ubiquitous Computing scenarios that is able to reconfigure both application and non-functional features, in order to cope with increasingly complex and heterogeneous ubiquitous and pervasive landscapes.

Middleware for automatic dynamic reconfiguration of context-driven services

In the emerging ubiquitous Internet scenario users require to access services and contents from anywhere, at anytime and with any device. Service and content provisioning platforms have to address several ubiquity challenges such as mobility, multimodality, context-awareness and content adaptation. However, current solutions fail to comprehensively face ubiquity challenges as they lack a unified approach and provide only limited sets of features. We claim that an integrated ubiquity support can stem from a simplicity principle: our middleware approach pushes the logic to face ubiquity issues outside the core layer, by keeping only management and coordination responsibilities. That succeeds in making the middleware design clearer and neater. This article presents the key architectural aspects of our platform for ubiquitous dynamic context-driven service provisioning and reconfiguration. To practically show the viability of our approach, we also provide implementation details and description of typical use cases.

A user-centric composition model for the Internet of Services

In the modern Internet of services scenarios, users need to create, share and access contents and services in extremely personalized ways and by means of heterogeneous devices and interaction channels. The most promising architectural solutions to cope with such dynamic and ever-growing scenario adopt a service oriented approach and leverage service composition platforms to flexibly arrange new value-added services made up of basic off-the-shelf components. Though, current solutions for service composition target rather static scenarios and scarcely support todays dynamic Web, where new services and contents continually become available to satisfy novel user needs and service compositions may become obsolete and need reconfiguration. We propose a novel composition model that aims at being extremely flexible and extensible, yet remaining easily usable by hiding complexity to users.

Middleware for Automatic Dynamic Reconfiguration of Context-Driven Services

In the emerging ubiquitous Internet scenario users require to access services and contents from anywhere, at anytime and with any device. Due to this requirement, platforms for service and content provisioning have to address several problems related to the new issues of mobility, multimodality, context awareness and content adaptation. However, current ubiquitous service provisioning platforms still suffer a main drawback: they often underestimate platform logic complexity when multiple ubiquity features should be provided. As a result, the proposed solutions lack a unified approach to the ubiquity issues and provide only limited sets of features. We claim that an integrated and comprehensive solution can stem from a simplicity principle: our approach pushes ubiquity features outside the core middleware layer, by keeping only management and coordination responsibilities. That succeeds in making the middleware design clearer and neater. In this paper we present the key architectural aspects of our middleware platform for ubiquitous dynamic context-driven service provisioning and reconfiguration. We also provide implementation details and description of typical use cases our platform successfully realizes.

iPOJO-based Middleware Solutions for Self-Reconfiguration and Self-Optimization

In recent years, ubiquitous and pervasive scenarios have emerged as a complex ecosystem where differentiated software/hardware components interoperate wirelessly and seamlessly. The goal is to enable users to continuously access services and contents, and to always get the best out of their current environment and available resources. In such dynamic and flexible scenarios, the need emerges for flexible and general solutions for continuous runtime self-reconfiguration and self-optimization of ubiquitous support software systems. This paper proposes a fully reconfigurable middleware approach that aims at reconfiguring complex software systems made up of heterogeneous off-the-shelf components from both functional and non-functional perspectives. Our middleware can also extend already existing and non-reconfigurable middleware/applications in an easy and flexible way, with no need to re-design them. The proposed design principles have been practically applied to the implementation of a runtime self-reconfigurable middleware called Off-The-Shelf Ready To Go (OTS-RTG), implemented on top of iPOJO. The reported experimental results both exhibit a limited overhead and show the wide applicability of the proposed solution to many application scenarios, including complex, industrial, Enterprise Service Bus-based ones.

Dynamic Reconfiguration of Middleware for Ubiquitous Computing

Ubiquitous computing scenarios call for middleware support solutions able to cope with changes in environment conditions and user requirements. Changes greatly impact on the application logic the middleware is able to carry out content/service adaptation, multichannel content delivery, mobility management, and so on, but also on the non-functional support logic middleware exploits to enforce the application logic itself e.g., naming, persistence, communication infrastructures. In this work, the authors propose a novel middleware for ubiquitous computing scenarios that is able to reconfigure both application and non-functional features, in order to cope with increasingly complex and heterogeneous ubiquitous and pervasive landscapes.

A federation model to support semantic SPARQL queries for enterprise data governance

Data Governance and Federation in large complex organizations poses non-trivial challenges due to the integration of heterogeneous, distributed data sources. Semantic Web, and its de-facto standard query language — SPARQL — have proven to be key in defining and searching semantic over any sort of content on the Web, thus easily letting content clients discover hidden relationships among disparate data. However, current SPARQL support of Data Federation is fairly limited, making it impractical for real-world scenarios. Our work proposes an open and autonomous platform for Data Federation that overcome traditional SPARQL limitations and opens up unprecedented opportunities for Data Governance in large organizations.

Facing crosscutting concerns in a middleware for pervasive Service composition

The emerging, ubiquitous Internet of Services scenario discloses a radical change in the process of content creation and service consumption. Thus, platforms for service and content provisioning should cope with several issues concerning mobility, context awareness and content adaptation. However, traditional programming paradigms, though proving their effectiveness in mastering a good separation of concerns, fall short when it comes to capture concerns that span and orthogonally crosscut several system components. In service-oriented architecture models that face the extremely dynamical and ever-changing above scenario, it is common and usual an undesirable tangling of functionalities which induces poor flexibility, accuracy and consistency. This paper investigates how an innovative and emerging methodology, Aspect-Oriented Programming, can address these issues in a middleware platform for ubiquitous dynamic context-driven service provisioning and configuration. We also distill some design principles and implementation details of the reengineering activities we accomplished.

NoMISHAP: A Novel Middleware Support for High Availability in Multicloud PaaS

The availability of multiple Platform as a Service (PaaS) environments, characterized by different actors, supported service models, and available components ease the engineering of new applications and facilitate their fast composition and elastic delivery. However, as demonstrated by the several outages that affected all main cloud providers along the last decade, when these applications come to a production stage there are still several open issues, especially for applications that must meet high availability requirements. This paper proposes NoMISHAP, a Novel Middleware Support for High Availability in multicloud PaaS. NoMISHAP provides the needed middleware support to develop of a new class of highly available services over multiple PaaS environments: it includes service component adapters to ease service migration between different PaaS and supports all needed monitoring, brokerage, and binding/deployment operations to enable transparent transitions between PaaS environments as failures occur at runtime. We deeply assessed NoMISHAP in a realistic scenario over Heroku, Bluemix, and Openshift PaaS platforms. Collected results show both the effectiveness of our solution and quantify the overhead, with the goal of demonstrating the suitability of middleware-based multicloud PaaS solutions to grant high availability.