Stefano Ceri's research while affiliated with Politecnico di Milano and other places

Publications (304)

Preprint
Full-text available
We released over 1 million tweets shared during 2019 and containing links to thousands of news articles published on two classes of Italian outlets: (1) disinformation websites, i.e. outlets which have been repeatedly flagged by journalists and fact-checkers for producing low-credibility content such as false news, hoaxes, click-bait, misleading an...
Preprint
We investigate the presence (and the influence) of disinformation spreading on online social networks in Italy, in the5-month period preceding the 2019 European Parliament elections. To this aim we collected a large-scale dataset oftweets associated to thousands of news articles published on Italian disinformation websites. In the observation perio...
Preprint
Full-text available
We investigate the presence (and the influence) of disinformation spreading on online social networks in Italy, in the5-month period preceding the 2019 European Parliament elections. To this aim we collected a large-scale dataset oftweets associated to thousands of news articles published on Italian disinformation websites. In the observation perio...
Article
Online social media are changing the news industry and revolutionizing the traditional role of journalists and newspapers. In this scenario, investigating the behaviour of users in relationship to news sharing is relevant, as it provides means for understanding the impact of online news, their propagation within social communities, their impact on...
Article
In the past few years, the research community has dedicated growing interest to the issue of false news circulating on social networks. The widespread attention on detecting and characterizing deceptive information has been motivated by considerable political and social backlashes in the real world. As a matter of fact, social media platforms exhib...
Preprint
Full-text available
In recent years, malicious information had an explosive growth in social media, with serious social and political backlashes. Recent important studies, featuring large-scale analyses, have produced deeper knowledge about this phenomenon, showing that disinformation spreads faster, deeper and more broadly than the truth on social media, where bots...
Preprint
Full-text available
In the past few years, the research community has dedicated growing interest to the issue of false news circulating on social networks. The widespread attention on detecting and characterizing false news has been motivated by considerable backlashes of this threat against the real world. As a matter of fact, social media platforms exhibit peculiar...
Article
Statistics and computer science are facing remarkably similar discussions on the role of big data. In this article, I advocate that the computer science community has taken advantage of big data since about five decades, thereby building the main commercial companies of today's computer industry, and specifically I describe the new emphasis on data...
Chapter
This book, dedicated to Ontoni Olivé, will be presented to him at the 36th International Conference on Conceptual Modeling; this tells us that conceptual modeling established as a research field about 40 years ago, when seminal works on conceptual modeling were published. Our research career started as well about 40 years ago, and modeling has been...
Chapter
In this chapter, we look at innovation leadership in action, specifically how the presence or lack of leadership has shaped the innovation process. We concentrate on complex problems and great challenges; indeed, such problems highlight where new leadership is required, as they feature higher dimensionality, and a great number of stakeholders with...
Chapter
Alta Scuola Politecnica (www.asp-poli.it, (ASP 2009)) was founded in 2004 by the Politecnico di Milano and Politecnico di Torino. It annually selects 150 talented students solely on the basis of merit, from among the applicants to the Master of Science in Engineering, Architecture and Design at the two universities. The resulting community is made...
Chapter
The previous chapters on innovation and the innovation ecosystem lead us to the central topic of this chapter: Innovation Leadership. In contrast to traditional forms of leadership, we reframe leadership as a modality as well as a mindset, and emphasize the need to define it as a capacity to create impact in an increasingly complex class of challen...
Article
Full-text available
A number of emerging crowd-based applications cover very different scenarios, including opinion mining, multimedia data annotation, localised information gathering, marketing campaigns, expert response gathering, and so on. In most of these scenarios, applications can be decomposed into tasks that collectively produce their results; tasks interacti...
Article
Objective Wine et al, (Plos ONE 2013 and 2014) recently published a bioassay for testing CFTR function in vivo. A ratio was computed between CFTR-independent (M-sweat, stimulated by methacholine) and CFTR-dependent (C-sweat, evoked by a b-adrenergic cocktail) sweat secretion rates by multiple individual glands, measured in a series of subjects. Sec...
Article
Full-text available
Improvement of sequencing technologies and data processing pipelines is rapidly providing sequencing data, with associated high-level features, of many individual genomes in multiple biological and clinical conditions. They allow for data-driven genomic, transcriptomic and epigenomic characterizations, but require state-of-the-art "big data" comput...
Conference Paper
Full-text available
This paper is focused on community-based crowdsourcing applications, i.e. the ability of spawning crowdsourcing tasks upon multiple communities of performers, thus leveraging the peculiar characteristics and capabilities of the community members. We show that dynamic adaptation of crowdsourcing campaigns to community behaviour is particularly relev...
Article
Full-text available
The huge amount of biomedical-molecular data increasingly produced is providing scientists with potentially valuable information. Yet, such data quantity makes difficult to find and extract those data that are most reliable and most related to the biomedical questions to be answered, which are increasingly complex and often involve many different b...
Article
Full-text available
Many efforts exist to design and implement approaches and tools for data capture, integration and analysis in the life sciences. Challenges are not only the heterogeneity, size and distribution of information sources, but also the danger of producing too many solutions for the same problem. Methodological, technological, infrastructural and social...
Article
Full-text available
Mega-modeling is a viable approach to data analysis by using a bottom-up, inductive method. Mega-models are large, autonomous computing systems whose interfaces are described through a data-centric approach and whose execution behavior can be inspected. Mega-modeling aims at defining a comprehensive theory and technology of model construction model...
Article
Full-text available
As a wealth of data services is becoming available on the Web, building and querying Web applications that effectively integrate their content is increasingly important. However, schema integration and ontology matching with the aim of registering data services often requires a knowledge-intensive, tedious, and error-prone manual process. We tackle...
Article
Exploratory search is an information seeking behavior where users progressively learn about one or more topics of interest; it departs quite radically from traditional keyword-based query paradigms, as it combines querying and browsing of resources, and covers activities such as investigating, evaluating, comparing, and synthesizing retrieved infor...
Article
Full-text available
Since the beginning of the Semantic Web initiative, significant efforts have been invested in finding efficient ways to publish, store, and query metadata on the Web. RDF and SPARQL have become the standard data model and query language, respectively, ...
Conference Paper
Full-text available
An essential aspect for building effective crowdsourcing com- putations is the ability of "controlling the crowd", i.e. of dynamically adapting the behaviour of the crowdsourcing systems as response to the quantity and quality of completed tasks or to the availability and reliability of performers. Most crowdsourcing systems only provide limited an...
Article
Full-text available
More and more applications require real-time processing of massive, dynamically generated, ordered data; order is an essential factor as it reflects recency or relevance. Semantic technologies risk being unable to meet the needs of such applications, as they are not equipped with the appropriate instruments for answering queries over massive, highl...
Conference Paper
Full-text available
The availability of huge amounts of data ("big data") is changing our attitude towards science, which is moving from specialized to massive experiments and from very focused to very broad research questions. Models of all kinds, from analytic to numeric, from exact to stochastic, from simulative to predictive, from behavioral to ontological, from p...
Conference Paper
Full-text available
Web users are increasingly relying on social interaction to complete and validate the results of their search activities. While search systems are superior machines to get world-wide information, the opinions collected within friends and expert/local communities can ultimately determine our decisions: human curiosity and creativity is often capable...
Chapter
With Fusion Tables, Google has made available a huge repository that allows users to share, visualize and manage structured data. Since 2009, thousands of tables have been shared online, encompassing data from virtually any domain and entered by all kinds of users, from professional to non-experts. While Fusion Tables are a potentially precious sou...
Conference Paper
Recent years witnessed an exponential increase in the number of data services available on the Web. Many popular Web sites, including social networks, offer API for interacting with their information, and open data initiative such as the Linked Data project promise to achieve the vision of the Web of data. Unfortunately, access to Web data is typic...
Article
This article presents the adaptation of a general search computing framework for exploratory search over Web data as suggested by the specificity of location-based data services. The result is a conceptual model of geographic entities, the spatial functions operating on them, and a special-purpose exploratory interface that lets users search combin...
Book
Search computing, which has evolved from service computing, focuses on building the answers to complex search queries by interacting with a constellation of cooperating search services, using the ranking and joining of results as the dominant factors for service composition. The field is multi-disciplinary in nature and takes advantage of contribut...
Article
Full-text available
An increasing number of bioinformatics web services are available that provide answer to specific data extraction and analysis needs. Yet, biomedical questions are often complex and regard many different aspects of an organism and its biomolecular entities. Their answer hence requires searching multiple heterogeneous data that frequently are inhere...
Article
In the Life Sciences, numerous questions can be addressed only by comprehensively searching different types of data that are inherently ordered, or are associated with ranked confidence values. We previously proposed Search Computing to support the integration of the results of search engines with other data and computational resources. This paper...
Chapter
Full-text available
This chapter focuses on the visualization of multi-domain search results. We start by positioning the problem in the recent line of evolution of search engine interfaces, which more and more are capable of mining semantic concepts and associations from text data and presenting them in sophisticated ways that depend on the type of the extracted data...
Conference Paper
We demonstrate Liquid Queries, a novel user interaction paradigm for exploratory multi-domain search upon structured information collected from heterogeneous data sources. Liquid Queries support an exploratory search approach by providing a set of interaction primitives for multi-domain query formulation, result visualization and query refinement,...
Conference Paper
Full-text available
Search Computing (SeCo) aims at building search applications that bridge the gap between general-purpose and vertical search engines. SeCo queries extract ranked information about several interconnected domains, such as "hotels", "restaurants" or "concerts", by interacting with Web data sources which are wrapped as search services; an example of qu...
Conference Paper
Web search is considered a playground for a few giants - such as Google, Yahoo! and Bing - that relegate the other players to market niches. However, Web search is far from satisfying all information needs, because many search queries are complex, require information integration, and go beyond what can be offered by a single Web page; on these quer...
Article
Search computing focuses on building answers to complex search queries (for example, "Where can I attend an interesting conference in my field near a sunny beach?") by interacting with a constellation of cooperating search services, and using result ranking and joining as the dominant factors for service composition. The service computing paradigm...
Article
Full-text available
A combined approach of deductive and inductive reasoning can leverage the clear separation between the evolving (streaming) and static parts of online knowledge at conceptual and technological levels. What are the hottest topics discussed on Twitter? Which topics have my close friends discussed in the last hour? Which movie is my friend most likely...
Article
Full-text available
Continuous SPARQL (C-SPARQL) is a new language for continuous queries over streams of RDF data. CSPARQL queries consider windows, i.e., the most recent triples of such streams, observed while data is continuously flowing. Supporting streams in RDF format guarantees interoperability and opens up important applications, in which reasoners can deal wi...
Article
Full-text available
Continuous SPARQL (C-SPARQL) is a new language for continuous queries over streams of RDF data. CSPARQL queries consider windows, i.e., the most recent triples of such streams, observed while data is continuously flowing. Supporting streams in RDF format guarantees interoperability and opens up important applications, in which reasoners can deal wi...
Chapter
Service-oriented architectures (SOA) provide the basis to (re)design business processes in order to develop flexible applications where available services are dynamically composed to satisfy business goals. The adoption of this type of architecture enables the design of information systems that connect IEs to each other to run collaborative busines...
Conference Paper
Full-text available
Search Computing defines a new class of applications, which enable end users to perform exploratory search processes over multi-domain data sources available on the Web. These applications exploit suitable models, supported by a framework, that make it possible for expert users to configure the data sources to be searched and the interfaces for que...
Conference Paper
The use of patterns in data management is not new: in data warehousing, data marts are simple conceptual schemas with exactly one core entity, describing facts, surrounded by multiple entities, describing data analysis dimensions; data marts support special analysis operations, such as roll up, drill down, and cube. Similarly, Service Marts are sim...
Conference Paper
Full-text available
This article presents a technique for Stream Reasoning, consisting in incremental maintenance of materializations of ontological entailments in the presence of streaming information. Previous work, delivered in the context of deductive databases, describes the use of logic programming for the incremental maintenance of such entailments. Our contrib...
Conference Paper
Full-text available
This article presents a technique for Stream Reasoning, consisting in incremental maintenance of materializations of ontological entailments in the presence of streaming information. Previous work, delivered in the context of deductive databases, describes the use of logic programming for the incremental maintenance of such entailments. Our contrib...
Article
This article defines C-SPARQL, an extension of SPARQL whose distinguishing feature is the support of continuous queries, i.e. queries registered over RDF data streams and then continuously executed. Queries consider windows, i.e. the most recent triples of such streams, observed while data is continuously flowing. Supporting streams in RDF format g...
Conference Paper
Full-text available
Data Streams - unbounded sequences of time-varying data elements - are pervasive. They occur in a variety of modern applications including the Web where blogs, feeds, and microblogs are increasingly adopted to distribute and present information in real-time streams. We foresee the need for languages, tools and methodologies for representing, managi...
Conference Paper
Search Computing (SeCo) is a project funded by the European Research Council (ERC). It focuses on building the answers to complex search queries like "Where can I attend an interesting conference in my field close to a sunny beach?" by interacting with a constellation of cooperating search services, using ranking and joining of results as the domin...
Article
Full-text available
Stream reasoning, an unexplored yet high impact research area, is a new multidisciplinary approach that can provide the abstractions, foundations, methods, and tools required to integrate data streams, the Semantic Web, and reasoning systems, thus providing a way to answer our initial questions and many others. Stream reasoning can benefit numerous...
Conference Paper
The Semantic Resource Framework (SRF) is a multi-level description of the data sources for search computing applications. It responds to the need of having a structured representation of search services, amenable to service exploration, selection, and invocation. The SRF aims at extending the Service Mart model used so far in search computing to ov...
Conference Paper
This paper reports the main findings of a panel about trends in search engine interaction, focused upon the use of search engines for performing complex processes. The discussion focuses on the different evolutionary path followed by search engines with respect to other Web and information management solutions, making end users acquainted with the...
Chapter
The efficient execution of data-intensive computations over services is a challenging task: data are retrieved from remote sources and therefore are not available in the query engine until after the execution of these calls, but the system must be inherently efficient thereafter, by guaranteeing that data is immediately cached and processed efficie...
Chapter
The efficient execution of data-intensive computations over services is a challenging task: data are retrieved from remote sources and therefore are not available in the query engine until after the execution of these calls, but the system must be inherently efficient thereafter, by guaranteeing that data is immediately cached and processed efficie...
Article
Search Computing is a new paradigm for composing search services. While state-of-art search systems answer generic or domain-specific queries, Search Computing enables answering questions via a constellation of dynamically selected, cooperating search services, which are correlated by means of join operations. The idea is simple, yet pervasive. New...
Book
Search computing, which has evolved from service computing, focuses on building the answers to complex search queries by interacting with a constellation of cooperating search services, using ranking and joining of results as the dominant factors for service composition. The field is multi-disciplinary in nature, and takes advantage of contribution...
Conference Paper
Full-text available
Continuous SPARQL (C-SPARQL) is proposed as new language for continuous queries over streams of RDF data. It covers a gap in the Semantic Web abstractions which is needed for many emerging applications, including our focus on Urban Computing. In this domain, sensor-based information on roads must be processed to deduce localized traffic conditions...
Conference Paper
Search computing queries typically address search tasks that go beyond a single interaction. In this paper, we show a query paradigm that supports multi-step, exploratory search over multiple Web data sources. Our paradigm requires users to be aware of searching over “interconnected objects” with given semantics, but each exploration step is simpli...
Chapter
Joins between data sources are an essential ingredient of multi-domain queries, as they exploit connection patterns defined between service marts or between service interfaces. This chapter moves from the definition of a query language over service interfaces, sketching how queries can be directly expressed over service marts and how these can be t...
Conference Paper
Liquid queries are a flexible tool for information seeking, based on the progressive exploration of the search space; they produce “fluid” results which dynamically adapt to the shape of the query, as a liquid adapts to its container. The liquid query paradigm relies on the SeCo service mart and multi-domain query execution concepts: an expert user...
Conference Paper
Full-text available
Many tasks in bioinformatics require the comprehensive evaluation of different types of data, generally available in distributed and heterogeneous data sources. Several approaches, including federated databases, multi databases and mediator based systems, have been proposed to integrate data from multiple sources. Yet, data warehousing seams to be...
Article
While business process definition is becoming more and more popular as an instrument for describing human activities, there is a growing need for software tools supporting business process abstractions to help users organize and monitor their desktop work. Tools are most effective when they embed some knowledge about the process, e.g., in terms of...
Conference Paper
Full-text available
The level of maturity that has been reached by model transformation technologies is proved by the growing literature on transformation libraries that address an increasingly wide spectrum of applications. With the success of the modeling and transformation paradigm, the need arises to address more complex applications that require a direct manipula...
Conference Paper
ldquoWho are the strongest European competitors on software ideas? Who is the best doctor to cure insomnia in a nearby hospital? Where can I attend an interesting conference in my field close to a sunny beach?rdquo This information is available on the Web, but no software system can accept such queries nor compute the answer. We hereby propose sear...
Conference Paper
Full-text available
While reasoners are year after year scaling up in the classical, time invariant domain of ontological knowledge, reasoning upon rapidly changing information has been neglected or forgotten. On the contrary, processing of data streams has been largely investigated and specialized Stream Database Management Systems exist. In this paper, by coupling r...
Chapter
In this chapter we compare two solutions to the mediation scenario of the SWS challenge that are based on the use of WebML [1] and of the jABC [2, 3] as modeling and execution platforms. In particular, first we give a general overview of the differences among the to approaches, and then we compare in the details the two solutions for the SWS challe...
Conference Paper
The use of patterns in data management is not new: in data warehousing, data marts are simple conceptual schemas with exactly one core entity, describing facts, surrounded by multiple entities, describing data analysis dimensions; data marts support special analysis operations, such as roll up, drill down, and cube. Similarly, service marts are sim...
Chapter
In this chapter we compare the WSMO/WSML/WSMX andWebML/WebRatio approaches to the SWS-Challenge workshop mediation scenario in terms of the utilized underlying technologies and delivered solutions. In the mediation scenario one partner uses RosettaNet to define its B2B protocol while the other one operates on a proprietary solution. Both teams show...
Conference Paper
Full-text available
Answering multi-domain queries requires the combination of knowledge from various domains. Such queries are inadequately answered by general-purpose search engines, because domain- specific systems typically exhibit sophisticated knowledge about their own fields of expertise. Moreover, multi-domain queries typically require combining in the result...
Conference Paper
Full-text available
Social semantic data are becoming a reality, but apparently their streaming nature has been ignored so far. Streams, being unbounded sequences of time-varying data elements, should not be treated as persistent data to be stored “forever” and queried on demand, but rather as transient data to be consumed on the fly by queries which are registered on...
Conference Paper
Full-text available
C-SPARQL is an extension of SPARQL to support contin- uous queries over RDF data streams. Supporting streams in RDF format guarantees interoperability and opens up important applications, in which reasoners can deal with knowledge that evolves over time. We present C-SPARQL by means of examples in Urban Computing.
Conference Paper
Full-text available
This work presents a retrospective analysis on the conceptual modeling language for Web applications called WebML, which was first defined about 10 years ago. WebML has been an incubator for research on conceptual modeling, exploiting existing experiences in the field and continuously addressing new challenges concerning abstractions, methods, tool...
Conference Paper
Search Computing aims at opening the Web to a new class of search applications, by offering enhanced expressive and computational power. The success of Search Computing, as of any technical advance, will be measured by its impact upon the search industry and market, and this in turn will be highly influenced by reactions of Web users and developers...
Article
Full-text available
Data streams occur in a variety of modern applications. Specialized Stream Database Management Systems proved to be an optimal solution for on the y analysis of data streams, but they cannot perform complex reasoning tasks that requires to combine the streaming data with less time variant knowledge. At the same time, while reasoners are year after...
Conference Paper
Search computing is a novel discipline whose goal is to answer complex, multi-domain queries. Such queries typically require combining in their results domain knowledge extracted from multiple Web resources; therefore, conventional crawling and indexing techniques, which look at individual Web pages, are not adequate for them. In this paper, we ske...