Elena Pagani

University of Milan | UNIMI · Department of Computer Science

The increased adoption of the Internet Protocol (IP) in ICSs has made these systems vulnerable to the same security risks that are present in traditional IT environments. The legacy nature of ICSs and their unique operational requirements make them vulnerable to security threats that are different from those in IT environments. In this paper, we de...

Disease detection from smartphone data represents an open research challenge in mobile health (m-health) systems. COVID-19 and its respiratory symptoms are an important case study in this area and their early detection is a potential real instrument to counteract the pandemic situation. The efficacy of this solution mainly depends on the performanc...

In this paper, we propose a novel tag-based recommender system called PLIERS, which relies on the assumption that users are mainly interested in items and tags with similar popularity to those they already own. PLIERS is aimed at reaching a good tradeoff between algorithmic complexity and the level of personalization of recommended items. To evalua...

In recent months, the monkeypox (mpox) virus -- previously endemic in a limited area of the world -- has started spreading in multiple countries until being declared a ``public health emergency of international concern'' by the World Health Organization. The alert was renewed in February 2023 due to a persisting sustained incidence of the virus in...

Disease detection from smartphone data represents an open research challenge in mobile health (m-health) systems. COVID-19 and its respiratory symptoms are an important case study in this area and their early detection is a potential real instrument to counteract the pandemic situation. The efficacy of this solution mainly depends on the performanc...

The current availability of interconnected portable devices, and the advent of the Web 2.0, raise the problem of supporting anywhere and anytime access to a huge amount of content, generated and shared by mobile users. In this work we propose a novel framework for pervasive social networks, called Pervasive PLIERS (pPLIERS), able to discover and se...

Smartphones and wearable devices, along with Artificial Intelligence, can represent a game-changer in the pandemic control, by implementing low-cost and pervasive solutions to recognize the development of new diseases at their early stages and by potentially avoiding the rise of new outbreaks. Some recent works show promise in detecting diagnostic...

Data distribution is a cornerstone of efficient automation for intelligent machines in Industry 4.0. Although in the recent literature there have been several comparisons of relevant methods, we identify that most of those comparisons are either theoretical or based on abstract simulation tools, unable to uncover the specific, detailed impacts of t...

Since the nineties, the Man-in-The-Middle (MITM) attack has been one of the most effective strategies adopted for compromising information security in network environments. In this paper, we focus our attention on ARP cache poisoning, which is one of the most well-known and more adopted techniques for performing MITM attacks in Ethernet local area...

In this paper we discuss the state of the art of (mobile) multi-hop ad hoc networking with the aim to present the current status of the research activities and identify the consolidated research areas, with limited research opportunities, and the hot and emerging research areas for which further research is required. We start by briefly discussing...

We develop quantifier elimination procedures for fragments of higher order logic arising from the formalization of distributed systems (especially of fault-tolerant ones). Such procedures can be used in symbolic manipulations like the computation of pre/post images and of projections. We show in particular that our procedures are quite effective in...

Quite often, verification tasks for distributed systems are accomplished via counter abstractions. Such abstractions can sometimes be justified via simulations and bisimulations. In this work, we supply logical foundations to this practice, by a specifically designed technique for second order quantifier elimination. Our method, once applied to spe...

Enriching logic formalisms with counting capabilities is an important task in view of the needs of many application areas, ranging from database theory to formal verification. In this paper, we consider a very expressive language obtained by enriching linear integer arithmetic with free function symbols and cardinality constraints for interpreted s...

Internet protocols are intrinsically complex to understand and validate, due both to the potentially unbounded number of entities involved, and to the complexity of interactions amongst them. Yet, their safety is indispensable to guarantee the proper behavior of a number of critical applications.

The current availability of interconnected portable devices, and the advent of the Web 2.0, raise the problem of supporting anywhere and anytime access to a huge amount of content, generated and shared by mobile users. On the one hand, users tend to be always connected for sharing experiences and conducting their social interactions with friends an...

Online social networks (OSNs) allow users to generate items and tag or rate them in order to help others in the identification of useful content. In this paper, we propose a novel tag-based recommender system called PLIERS, able to identify useful contents based on users' interests. It relies on the assumption that users are mainly interested in it...

We identify a fragment of Presburger arithmetic enriched with free function symbols and cardinality constraints for interpreted sets, which is amenable to automated analysis. We establish decidability and complexity results for such a fragment and we implement our algorithms. The experiments run in discharging proof obligations coming from invarian...

In this paper, we discuss the state of the art of (mobile) multi-hop ad hoc networking with the aim to present the current status of the research activities and identify the consolidated research areas, with limited research opportunities, and the hot and emerging research areas for which further research is required. We start by briefly discussing...

In the era of pervasive mobile computing, human encounters can be leveraged to enable new forms of social interactions mediated by the personal devices of individuals. In this framework, emerging needs, such as content dissemination, social discovery and question and answering, advocate the raising of novel communication paradigms where the binding...

The 2014 Special issue of Computer Communications is dedicated to opportunistic networks (OppNets), which are an instance of the delay tolerant networking (DTN) paradigm. There are three algorithmic papers that propose and evaluate new forwarding schemes for opportunistic networks. GAR, a group-aware forwarding scheme is introduced in a paper for c...

This paper focuses on content dissemination in location-centered communities and provides the first comparative analysis of two forwarding algorithms on real scenario, namely, ProfileCast - which has been on purposely designed for this environment - and InterestCast - which by contrast addresses more general settings. The paper provides quantitativ...

In the era of pervasive mobile computing, human encounters can be leveraged to enable new forms of social interactions mediated by the personal devices of individuals. In this framework, emerging needs, such as content dissemination, social discovery and question&answering, advocate the raising of novel communication paradigms where the binding con...

Opportunistic Networks (OppNets) offer a very volatile and dynamic networking environment. Several applications proposed for OppNets - such as social networking, emergency management, pervasive and urban sensing - involve the problem of sharing content amongst interested users. Despite the fact that nodes have limited resources, existing solutions...

Rank-based policies represent a promising approach for designing message forwarding algorithms that meet the needs of opportunistic networks. In fact, they combine low computation and communication costs with good performance in terms of both latency and delivery rates. Nonetheless, they highly depend on the mobility scenario relevant to the user,...

Several proposals are available in the literature that deal with the problem of message forwarding in Opportunistic Networks (ONs). These proposals attempt to derive the path from source to destination that minimizes delivery latency and traveled hops, and maximizes the probability of successful delivery, while saving the overall system resources t...

The massive spread of small personal devices equipped with different radio technologies is enabling the formation of a heterogeneous wireless networking platform on top of which new mobile computing services are deployed to flexibly and ubiquitously reach a target user. With the emerging of ubiquitous wireless communications, mobile applications ar...

Model Checking Modulo Theories is a recent approach for the automated verification of safety properties of a class of infinite state systems manipulating arrays, called array-based systems. The idea is to repeatedly compute pre-images of a set of (unsafe) states by using certain classes of first-order formulae representing sets of states and transi...

We introduce a wait-and-chase scheme that models the contact times between moving agents within a connectionist construct. The idea that elementary processors move within a network to get a proper position is borne out both by biological neurons in the brain morphogenesis and by agents within social networks. From the former, we take inspiration to...

The workshop is sponsored by IEEE and IEEE Computer society, and jointly organized by the EU FET-PerAda SOCIALNETS and EU FP7-FIRE SCAMPI projects.

Mobile computing services are becoming highly personalized and influenced by user location, social attitudes and interests. This trend is often synthesized with the term behavior-awareness. Behavioral services characterize most of the applications of Opportunistic Networks and advocate a single communication paradigm: multicast. Despite that, multi...

People’s inclination to move and meet while engaging in social relationships generates a wide set of contacts ranging from a few seconds to hours. This paper focuses mainly on the role of short contacts and shows how they are essential to the efficiency, stability and simple computation of the forwarding process, thus making affordable in practice...

We propose a methodology to use the infinite state model checker MCMT, based on Satisfiability Modulo Theory techniques, for assisting in the design of fault tolerant algorithms. To prove the practical viability of our methodology, we apply it to formally check the agreement property of the reliable broadcast protocols of Chandra and Toueg.

The broadcast diffusion of messages in Delay Tolerant Networks (DTNs) is heavily dependent on nodes mobility, since protocols must rely on contact opportunities among devices to diffuse data. This work is a first effort to study how the dynamics of nodes affect both the effectiveness of the broadcast protocols in diffusing data, and their efficienc...

Background and motivations. Algorithms for ensuring fault tolerance are key ingredients in many applications such as avionics and networking. There is an increasing demand to integrate (formal) validation in the design process of these algorithms as they are often part of safety critical systems.When validation fails, the designer would benefit fro...

This paper describes a novel Android-based opportunistic platform for mobile computing applications. It has the aim to incentive the growth of practical experiences that should give an answer to the following question: can Opportunistic Networks actually compete with cellular networks to support urban-wide mobile computing applications?

In this last two years an increasing number of scientists has devoted his attention to Vehicular Ad hoc NETworks (VANETs) as a special case of the more generic Mobile Ad hoc NETworks (MANETs). A public transportation network used as a VANET backbone may be a viable solution - under certain circumstances - also thanks to its almost-complete area cov...

We propose a methodology to use the infinite state model checker MCMT, based on Satisfiability Modulo Theory techniques, for assisting in the design of fault tolerant algorithms. To prove the practical viability of our methodology, we apply it to formally check the agreement property of the reliable broadcast protocols of Chandra and Toueg.

The broadcast diffusion of messages in Delay Tolerant Networks (DTNs) is heavily dependent on nodes mobility, since protocols must rely on contact opportunities among devices to diffuse data. This work is a first effort to study how the dynamics of nodes affect both the effectiveness of the broadcast protocols in diffusing data, and their efficienc...

So far, the search for Opportunistic Network (ON) applica- tions has focused on urban/rural scenarios where the com- bined use of mobility and the store-carry-and-forward para- digm helpfully recovers from network partitions and copes with node sparsity. This paper explores the chance of using ONs in workplaces, where the node distribution is dense...

This paper envisions an urban scenario where people carry radio devices that can be dynamically networked, by exploiting human contact opportunities, to create unplanned, improvised and localized wireless connectivity, which has been recently called pocket switched networks (PSN).The paper focuses on the radio device (pocket mobility trace recorder...

The broadcast diffusion of messages in Delay Tolerant Networks (DTNs) is heavily dependent on nodes mobility, since protocols must rely on contact opportunities among devices to diffuse data. This work is a first effort to study how the dynamics of nodes affect both the effectiveness of the broadcast protocols in diffusing data, and their efficienc...

Current search engines are rapidly changing to embrace more powerful mechanisms that are capable of reasoning on semantic attributes of contents in a distributed repository. Formalisms have been proposed to represent the semantic attributes. Yet, traditional approaches for content sharing in peer-to-peer systems cannot be adapted to use semantic in...

In this work, we present an analysis of the gain achieved in terms of efficiency with PUSH-based epidemic diffusion of messages, when maintaining and exchanging information about the infection status. Different policies for the exchange of partial status information are compared, with the aim of optimizing bandwidth usage. We analyze the effects of...

The broadcast diffusion of messages in Delay Tolerant Networks (DTNs) is heavily dependent on the mobility of the nodes, since protocols must rely on contact opportunities among devices to diffuse data. This work is the first effort of studying how the dynamics of nodes affect both the effectiveness of the broadcast protocols in diffusing the data,...

In delay and disruption tolerant networks, DTNs, the broadcast communications have been so far disregarded under the conviction that their cost is unaffordable in the presence of highly sparse and mobile nodes. This paper defines the problem of a topology-independent broadcast in DTNs in terms of effectiveness and efficiency, and provides some inte...

In the last years, the availability of cheap mobile devices able to communicate via radio interfaces a nd equipped with low cost positioning technologies, like GPS, has brough t to researcher attention a new kind of services: l ocation based services (LBS). LBS require users to provide their po sition in order to customize the service. This, of cou...

The authors have previously been active in developing a learning management system, applying it to computer- assisted assessment (CAA) tasks, improvising in-class ac- tivities using students' cellphones as text-messaging ter mi- nals, and devising architectures and prototypes to apply ad hoc networking to distributed computer-mediated commu- nicati...

Context network is the result of the integration of wireless sensor network (WSN) and context-awareness which are primarily reconsidered in terms of granular computing. It is aimed to be reliable infrastructure for providing applicable and proper contextual information necessary for developing realistic context-aware applications.

This paper describes how a laboratory where students usu- ally access the LAN using personal accounts can be con- figured during examinations. Test questions are automati- cally corrected by a learning-management system, which is used to authenticate students (who are further identified by physical presence). During assessment conditions, students...

Respecting the mobile world, it is about the time to demand for systems to fully take advantage of their environment. In this way, Enhanced Sensor Network is another step toward developing realistic context-aware applications, which is based on the basic infrastructures provided by wireless sensor networks (WSN) and context-aware application develo...

The term e-learning indicates products that differ very much both in services supplied and in design. E-learning platforms do not necessarily involve networking as a fundamental component. However, networking is important both to ease access to course material and to support interaction among users. Networking should be exploited to allow remote ac...

The term e learning indicates products that differ very much both in services supplied and in design. E learning platforms do not necessarily involve networking as a fundamental component. However, networking is important both to ease access to course material and to support interaction among users. Networking should be exploited to allow remote ac...

This paper proposes a distributed platform designed to support pervasive learning and interactivity on a university campus and to ease tasks related to learning and teaching. The platform exploits wireless technologies in order to provide service access anywhere and anytime. The platform architecture is described, and the functionalities of the mod...

Use of wireless technologies is becoming pervasive in everyday life. Recently, research began analyzing their use on board of vehicles for several kinds of applications, ranging from traffic safety to fleet management and cooperative work, to entertainment and Internet browsing. In this work, we focus on safety applications and in particular on the...

This paper describes classroom practices based on interact-ing with students through their mobile phones, using a min-imum of dedicated technology. Students'sense of propri-etorship over such devices has led to results that continue to stimulate our current research efforts. The technologically impoverished teaching tactics first devised to fit tec...

Vehicular ad hoc networks are studied with increasing interest for the many possible applications they have. Equipping vehicles with wireless devices primarily al- lows to design protocols and mechanisms to improve street safety. But also distributed applications for cooperative work, fleet management, passengers entertainment, could be supported....

Peer-to-peer (P2P) systems have recently become popular for content sharing, and a number of different approaches have been studied to perform effective content retrieval in such networks. We discuss how conventional P2P network policies for content retrieval could be combined with a semantic engine component to enforce peer-based knowledge sharing...

In this paper, we propose the On-Demand Bluetooth scatternet formation algorithm (ODBT). ODBT characterizes an ad hoc infrastructure with a tree topology. It is able to cope with topology changes due to either leaving or moving Bluetooth devices, as well as with devices that dynamically join the scatternet. It can support out-of-range devices. We d...

At the Dipartimento di Informatica e Comunicazione of the Universi a Statale di Milano an opportunity for exam automation was seen in an earlier initiative that had led to the development of an open-source learning management system. This LMS, known as "Just Learn It!" (or JLI!) was then applied to English-as-a-foreign-language place-ment tests for...

In this work, we describe the implementation of an architecture to perform admission control and traffic management for multicast sessions in Diff-Serv networks. The Bandwidth Broker functionalities are carried out by the Call Admission Multicast Protocol (CAMP). CAMP performs the set-up of a multicast RTP session. It supports dynamic changes in th...

An appealing approach to the admission control problem for traffic with QoS requirements consists in evaluating the resource availability by means of measurement- based techniques. Those techniques allow to provide QoS with minimal changes to the current network devices. In this work, we propose a mechanism to perform active measurement-based admis...

The differentiated services model is the emerging standard to provide Quality-of-Service (QoS) support for multimedia applications in the future Internet. This model involves bandwidth broker agents performing admission control and network configuration functionalities. A great deal of effort has been recently devoted to investigate viable approach...