Cristiana Bolchini

Bio: Cristiana Bolchini is an academic researcher from Polytechnic University of Milan. The author has contributed to research in topics: Fault detection and isolation & Fault tolerance. The author has an hindex of 26, co-authored 158 publications receiving 2527 citations. Previous affiliations of Cristiana Bolchini include University of Milan & Polytechnic University of Turin.

A data-oriented survey of context models

Abstract: Context-aware systems are pervading everyday life, therefore context modeling is becoming a relevant issue and an expanding research field. This survey has the goal to provide a comprehensive evaluation framework, allowing application designers to compare context models with respect to a given target application; in particular we stress the analysis of those features which are relevant for the problem of data tailoring. The contribution of this paper is twofold: a general analysis framework for context models and an up-to-date comparison of the most interesting, data-oriented approaches available in the literature.

TMR and Partial Dynamic Reconfiguration to mitigate SEU faults in FPGAs

Abstract: This paper presents the adoption of the triple modular redundancy coupled with the partial dynamic reconfiguration of field programmable gate arrays to mitigate the effects of soft errors in such class of device platforms. We propose an exploration of the design space with respect to several parameters (e.g., area and recovery time) in order to select the most convenient way to apply this technique to the device under consideration. The application to a case study is presented and used to exemplify the proposed approach.

And what can context do for data

Abstract: Common to all aCtors in today’s information world is the problem of lowering the “information noise,” both reducing the amount of data to be stored and accessed, and enhancing the “precision” according to which the available data fit the application requirements. Thus, fitting data to the application needs is tantamount to fitting a dress to a person, and will be referred to as data tailoring. The context will be our scissors to tailor data, possibly assembled and integrated from many data sources. Since the 1980s, many organizations have evolved to comply with the market needs in terms of flexibility, effective customer relationship management, supply chain optimization and so on and so forth: the situation where a set of partners re-engineered their single organizations, generating a unique, extended enterprise, has frequently been observed. Together with the organizations, also their information systems evolved, embracing new technologies like XML and ontologies, used in ERP systems and Webservice based applications. In recent years many organizations introduced into their information systems also Knowledge Management features, to allow easy information sharing among the organizations’ members; these new information sources and their content have to be managed together with other – we might say legacy – enterprise data. This growth of information, if not properly controlled, leads to a data overload that may cause confusion rather than knowledge, and dramatically reduce the benefits of a rich information system. However, distinguishing useful information from noise, i.e., from all the information not relevant to the specific application, is not a trivial task; the same piece of information can be considered differently, even by the same user, in different situations, or places – in a single word, in a different context. The notion of context, formerly emerged in various fields of research like psychology and philosophy, is acquiring great importance also in the computer science field. In a commonsense interpretation, the context is perceived as a set of variables that may be of interest for an agent and that influence its actions. The context has often a significant impact on the way humans (or machines) interpret their environment: a change in context causes a transformation in the actor’s mental representation of the reality, even when the reality is not changed. The word itself, derived from the Latin cum (with or together) and texere (to weave), describes a context not just as a profile, but as an active process dealing with the way humans weave their experience within their whole environment, to give it meaning. In the last few years, sophisticated and general context models have been proposed to support context-aware applications. In the following we list the different meanings attributed to the word context: Presentation-oriented: ˲ context is perceived as the capability of the system to adapt content presentation to different channels or to different devices. These context-models are often rigid, since they are designed for specific applications and rely on a well known set of presentation variables. Location-oriented: ˲ with this family of context models, it is possible to handle and What can context do for data?

Combined DVFS and mapping exploration for lifetime and soft-error susceptibility improvement in MPSoCs

Abstract: Energy and reliability optimization are two of the most critical objectives for the synthesis of multiprocessor systems-on-chip (MPSoCs). Task mapping has shown significant promise as a low cost solution in achieving these objectives as standalone or in tandem as well. This paper proposes a multi-objective design space exploration to determine the mapping of tasks of an application on a multiprocessor system and voltage/frequency level of each tasks (exploiting the DVFS capabilities of modern processors) such that the reliability of the platform is improved while fulfilling the energy budget and the performance constraint set by system designers. In this respect, the reliability of a given MPSoC platform incorporates not only the impact of voltage and frequency on the aging of the processors (wear-out effect) but also on the susceptibility to soft-errors -- a joint consideration missing in all existing works in this domain. Further, the proposed exploration also incorporates soft-error tolerance by selective replication of tasks, making the proposed approach an interesting blend of reactive and proactive fault-tolerance. The combined objective of minimizing core aging together with the susceptibility to transient faults under a given performance/energy budget is solved by using a multi-objective genetic algorithm exploiting tasks' mapping, DVFS and selective replication as tuning knobs. Experiments conducted with real-life and synthetic application graphs clearly demonstrate the advantage of the proposed approach.

A Novel Design Methodology for Implementing Reliability-Aware Systems on SRAM-Based FPGAs

Abstract: This paper presents a novel design flow for the implementation of digital systems onto SRAM-based FPGAs with soft error mitigation properties. Traditional fault detection/tolerance techniques are coupled with the device dynamic reconfiguration property to achieve soft error mitigation capabilities, and are applied to the single component, to groups of components or to the entire system, based on the most convenient trade-off with respect to a set of parameters. The design flow performs a two-steps multiobjective design space exploration, driven by a cost function taking into account resource utilization, area, and reconfiguration time. A floorplanning based on precise FPGA resource models is introduced to guarantee the feasibility of the hardened solution, identifying a convenient mapping onto the heterogeneous reconfigurable fabric. Experimental results show that the achieved solutions, aimed at achieving a prompt, "on demand” recovery when fault occurs, are characterized by a reduction in reconfiguration time that is higher than 80 percent, a significant improvement with respect to classical solutions.

Ontology Matching

Abstract: Ontologies tend to be found everywhere. They are viewed as the silver bullet for many applications, such as database integration, peer-to-peer systems, e-commerce, semantic web services, or social networks. However, in open or evolving systems, such as the semantic web, different parties would, in general, adopt different ontologies. Thus, merely using ontologies, like using XML, does not reduce heterogeneity: it just raises heterogeneity problems to a higher level. Euzenat and Shvaikos book is devoted to ontology matching as a solution to the semantic heterogeneity problem faced by computer systems. Ontology matching aims at finding correspondences between semantically related entities of different ontologies. These correspondences may stand for equivalence as well as other relations, such as consequence, subsumption, or disjointness, between ontology entities. Many different matching solutions have been proposed so far from various viewpoints, e.g., databases, information systems, and artificial intelligence. The second edition of Ontology Matching has been thoroughly revised and updated to reflect the most recent advances in this quickly developing area, which resulted in more than 150 pages of new content. In particular, the book includes a new chapter dedicated to the methodology for performing ontology matching. It also covers emerging topics, such as data interlinking, ontology partitioning and pruning, context-based matching, matcher tuning, alignment debugging, and user involvement in matching, to mention a few. More than 100 state-of-the-art matching systems and frameworks were reviewed. With Ontology Matching, researchers and practitioners will find a reference book that presents currently available work in a uniform framework. In particular, the work and the techniques presented in this book can be equally applied to database schema matching, catalog integration, XML schema matching and other related problems. The objectives of the book include presenting (i) the state of the art and (ii) the latest research results in ontology matching by providing a systematic and detailed account of matching techniques and matching systems from theoretical, practical and application perspectives.

Context-aware systems

Abstract: Nowadays, numerous journals and conferences have published articles related to context-aware systems, indicating many researchers' interest. Therefore, the goal of this paper is to review the works that were published in journals, suggest a new classification framework of context-aware systems, and explore each feature of classification framework. This paper is based on a literature review of context-aware systems from 2000 to 2007 using a keyword index and article title search. The classification framework is developed based on the architecture of context-aware systems, which consists of the following five layers: concept and research layer, network layer, middleware layer, application layer and user infrastructure layer. The articles are categorized based on the classification framework. This paper allows researchers to extract several lessons learned that are important for the implementation of context-aware systems.

Trends and challenges in VLSI circuit reliability

Abstract: Deep-submicron technology is having a significant impact on permanent, intermittent, and transient classes of faults. This article discusses the main trends and challenges in circuit reliability, and explains evolving techniques for dealing with them.

FPGA Architecture: Survey and Challenges

Abstract: Field-Programmable Gate Arrays (FPGAs) have become one of the key digital circuit implementation media over the last decade. A crucial part of their creation lies in their architecture, which governs the nature of their programmable logic functionality and their programmable interconnect. FPGA architecture has a dramatic effect on the quality of the final device's speed performance, area efficiency, and power consumption. This survey reviews the historical development of programmable logic devices, the fundamental programming technologies that the programmability is built on, and then describes the basic understandings gleaned from research on architectures. We include a survey of the key elements of modern commercial FPGA architecture, and look toward future trends in the field.