Motorola (Italy)

Skype is a very popular VoIP software which has recently attracted the attention of the research community and network operators. Following a closed source and proprietary design, Skype protocols and algorithms are unknown. Moreover, strong encryption mechanisms are adopted by Skype, making it very difficult to even glimpse its presence from a traffic aggregate. In this paper, we propose a framework based on two complementary techniques to reveal Skypetraffic in real time. The first approach, based on Pearson'sChi-Square test and agnostic to VoIP-related trafficcharacteristics, is used to detect Skype's fingerprint from the packet framing structure, exploiting the randomness introduced at the bit level by the encryption process. Conversely, the second approach is based on a stochastic characterization of Skype traffic in terms of packet arrival rate and packet length, which are used as features of a decision process based on Naive Bayesian Classifiers.In order to assess the effectiveness of the above techniques, we develop an off-line cross-checking heuristic based on deep-packet inspection and flow correlation, which is interesting per se. This heuristic allows us to quantify the amount of false negatives and false positives gathered by means of the two proposed approaches: results obtained from measurements in different networks show that the technique is very effective in identifying Skype traffic. While both Bayesian classifier and packet inspection techniques are commonly used, the idea of leveraging on randomness to reveal traffic is novel. We adopt this to identify Skype traffic, but the same methodology can be applied to other classification problems as well.

This study deals with model-based dependability transient analysis of phased mission systems. A review of the studies in the literature showed that several aspects of multiphased systems pose challenging problems to the dependability evaluation methods and tools. To attack the weak points of the state-of-the-art we propose a modeling methodology that exploits the power of the class of Markov regenerative stochastic Petri net models. By exploiting the techniques available in the literature for the analysis of the Markov Regenerative Processes, we obtain an analytical solution technique with a low computational complexity, basically dominated by the cost of the separate analysis of the system inside each phase. Last, the existence of analytical solutions allows us to derive the sensitivity functions of the dependability measures, thus providing the dependability engineer with additional means for the study of phased mission systems.

Skype is a very popular VoIP software which has recently attracted the attention of the research community and network operators. Following a closed source and proprietary design, Skype protocols and algorithms are unknown. Moreover, strong encryption mechanisms are adopted by Skype, making it very difficult to even glimpse its presence from a traffic aggregate. In this paper, we propose a framework based on two complementary techniques to reveal Skypetraffic in real time. The first approach, based on Pearson'sChi-Square test and agnostic to VoIP-related trafficcharacteristics, is used to detect Skype's fingerprint from the packet framing structure, exploiting the randomness introduced at the bit level by the encryption process. Conversely, the second approach is based on a stochastic characterization of Skype traffic in terms of packet arrival rate and packet length, which are used as features of a decision process based on Naive Bayesian Classifiers.In order to assess the effectiveness of the above techniques, we develop an off-line cross-checking heuristic based on deep-packet inspection and flow correlation, which is interesting per se. This heuristic allows us to quantify the amount of false negatives and false positives gathered by means of the two proposed approaches: results obtained from measurements in different networks show that the technique is very effective in identifying Skype traffic. While both Bayesian classifier and packet inspection techniques are commonly used, the idea of leveraging on randomness to reveal traffic is novel. We adopt this to identify Skype traffic, but the same methodology can be applied to other classification problems as well.

Multiple-Phased Systems (MPS), i.e., systems whose operational life can be partitioned in a set of disjoint periods, called "phases", include several classes of systems such as Phased Mission Systems and Scheduled Maintenance Systems. Because of their deployment in critical applications, the dependability modeling and analysis of Multiple-Phased Systems is a task of primary relevance. The phased behavior makes the analysis of Multiple-Phased Systems extremely complex. This paper describes the modeling methodology and the solution procedure implemented in DEEM, a dependability modeling and evaluation tool specifically tailored for Multiple Phased Systems. It also describes its use for the solution of representative MPS problems. DEEM relies upon Deterministic and Stochastic Petri Nets as the modeling formalism, and on Markov Regenerative Processes for the model solution. When compared to existing general-purpose tools based on similar formalisms, DEEM offers advantages on both the modeling side (sub-models neatly model the phase-dependent behaviors of MPS), and on the evaluation side (a specialized algorithm allows a considerable reduction of the solution cost and time). Thus, DEEM is able to deal with all the scenarios of MPS which have been analytically treated in the literature, at a cost which is comparable with that of the cheapest ones, completely solving the issues posed by the phased-behavior of MPS.

A novel approximate technique is proposed for the estimation of call blocking probabilities in cellular mobile telephony networks where call blocking triggers customer retrials. The approximate analysis technique is based on Markovian models with state spaces whose cardinalities are proportional to the maximum number of calls that can be simultaneously in progress within cells. The accuracy of the approximate technique is assessed by comparison against results of detailed simulation experiments, results of a previously proposed Markovian analysis approach, and upper and lower bounds to the call blocking probability. Numerical results show that the proposed approximate technique is very accurate, in spite of the remarkably small state spaces of the Markovian models.

Model adaptation techniques are an efficient way to reduce the mismatch that typically occurs between the training and test condition of any speech recognizer. Adaptation techniques can usually be divided into two families of approaches. On one hand, direct model adaptation attempts to directly reestimate the model parameters, for example using MAP adaptation. Since direct adaptation only reestimates model parameters of the corresponding units appearing in the adaptation data, a large amount of such data is needed to observe any significant improvement in performance. However, nice asymptotic properties are usually observed, meaning that the performance improves as the amount of adaptation data increases. On the other hand, indirect model adaptation applies a general transformation on some clusters of model parameters. Because each individual model is transformed, the approach is quite effective when a small amount of adaptation data is available. However, as the amount of adaptation data increases, the performance improvement quickly saturates. We propose to jointly estimate model parameters and transformation parameters using a single estimation criterion based on Bayesian statistics. We show that by providing a prior distribution for the model parameters and the transformation parameters, it is possible to jointly estimate these two sets of parameters using maximum a posteriori estimation (MAP). Experimental evaluation on nonnative speaker and channel adaptation illustrates the effectiveness of the proposed approach.

Multiple-phased systems, whose operational life can be partitioned into a set of disjoint periods called "phases", include several classes of systems, such as phased mission systems and scheduled maintenance systems. Because of their deployment in critical applications, the dependability modeling and analysis of multiple-phased systems is a task of primary relevance. However, the phased behavior makes the analysis of multiple-phased systems extremely complex. This paper is centered on the description and application of DEEM, a dependability modeling and evaluation tool for multiple-phased systems. DEEM supports a powerful and efficient methodology for the analytical dependability modeling and evaluation of multiple-phased systems, based on deterministic and stochastic Petri nets and on Markov regenerative processes.

Wireless beyond 3G is a new concept that envisions cellular, BFWA, and DVB systems cooperating in a composite radio infrastructure. In this scheme, instead of rejecting users or degrading their quality of service levels, a network provider can direct them to an alternate radio technology that meets certain environmental, cost, and QoS criteria. To achieve such a system requires upgrading service and network resource management (SNRM). We present work areas for a new SNRM approach that comprises the Universal Mobile Telecommunications System (UMTS), high-performance wireless local area network (HiperLAN 2) technology, and terrestrial DVB (DVB-T) systems.

Wireless Internet services such as mobile Web applications promise an enormous market potential. The field is characterized by extreme time-to-market pressure and insufficient knowledge about development procedures and technical constraints. This results in insufficient guidance for project managers and software developers on selecting appropriate development processes, techniques, methods, and tools. In addition, there is an enormous lack of knowledge about the effects (such as effort consumption, defect injection) of such technologies that hinders the transfer of innovative technologies into practice. This article describes an initial reference process by summarizing essential technologies for the development of wireless Internet services and experience with these technologies on the levels of life cycle processes, engineering processes, and managerial processes. The reference process is based on a comprehensive literature survey and the execution of development projects for wireless Internet services. The goal of the article is to provide domain-specific guidance for project managers and software developers with accompanying lessons learned from the past.

The General Packet Radio Service (GPRS) extends the Global System Mobile Communication (GSM) by introducing a packet-switched transmission service. This paper analyzes the GPRS behavior under critical conditions. In particular, we focus on outages, which significantly impact the GPRS dependability. In fact, during outage periods, the cumulative number of users trying to access the service grows proportionally over time. When the system resumes its operations, the overload caused by accumulated users determines a higher probability of collisions on resources assignment and, therefore, a degradation of the overall QoS. This paper adopts a stochastic activity network modeling approach for evaluating the dependability of a GPRS network under outage conditions. The major contribution of this study lies in the novel perspective the dependability study is framed in. Starting from a quite classical availability analysis, the network dependability figures are incorporated into a very detailed service model that is used to analyze the overload effect GPRS has to face after outages, gaining deep insights on its impact on user's perceived QoS. The result of this modeling is an enhanced availability analysis, which takes into account not only the bare estimation of unavailability periods, but also the important congestion phenomenon following outages that contribute to service degradation for a certain period of time after operations resume.

This paper describes a policy based management system envisaged to achieve management of networks and services in diversified radio environments. This work is conducted in the European project MONASIDRE currently developing a distributed management system for three coexisting technologies. The technologies are UMTS, Hiperlan and DVB. The common open policy service (COPS) has been selected to achieve part of the service and network management infrastructure.

COVID-19 had substantial effects on the IoT community which designs systems for safety: the urge to face masks worn by everyone, the analysis of crowds to avoid the spread of the disease, and the sanitization of public environments has led to exceptional research acceleration and fast engineering of the related solutions. Now that the pandemic is losing power, some applications are becoming less important, while others are proving to be useful regardless of the criticality of COVID-19. The Safe Place project is a prime example of this situation (DATE23 MPP category: final stage). Safe Place is an Italian 3M euro regional industrial/academic project, financed by European funds, created to ensure a multidisciplinary choral reaction to COVID-19 in critical environments such as rest homes and public places. Safe Place consortium was able to understand what is no longer useful in this post-pandemic period, and what instead is potentially attractive for the market. For example, the detection of face masks has little importance, while sanitization does have much. This paper shares such analysis, which emerged through a co-design process of three public Safe Place project demonstrators, involving heterogeneous figures spanning from scientists to lawyers.

Nowadays the high availability of more powerful portable devices paves the way to a new set of applications for a wide range of human activities. One important area of applications is related to road safety services, where human life is at stake. This paper describes an automated mobile system for the support of rescue and safety services personnel, as ambulance crew, fire brigades, and so on. The system is designed to accomplish several goals: to facilitate the rescue mission, to give update to a mission control center, to communicate additional information to rescue crew, to automate mission management. The work described in this paper has been accomplished in the framework of the European project GST.

International audience

This paper builds on the assumption that in the fourth generation (4G) wireless system context Universal Mobile Telecommunications System (UMTS), mobile broadband systems (MBS) and digital broadcasting systems (DBS) can be three co-operating components that enable wireless access to IP-based services. Managing the resources of this powerful infrastructure in an aggregate manner and multi-operator scenario is a complex task. This paper presents an approach to the overall UMTS, MBS and DBS network and service management problem. Key points addressed are the development of open interfaces with service provider mechanisms and the heterogeneous managed infrastructure, performance monitoring, joint optimization of the UMTS, MBS and DBS resources in accordance with the service provider requests and the changing with time environment conditions. The architecture of a corresponding UMTS, MBS and DBS network and service management platform is presented, in terms of logical blocks, implementation options and validation approach.

può essere considerato sia un testimone critico che un profeta della moda verghiana sul grande schermo.Di questa voga pop, che ha consentito a un ampio pubblico nostrano di innamorarsi di alcuni capolavori rivisitati in chiave commerciale e deformata, l'autore del Giardino dei Finzi Contini ha illuminato cause e limiti.

The development of software for wireless services on the Internet is a challenging task due to the extreme time-to-market pressure, the newness of the application domain, and the quick evolution of the technical infrastructure. Nevertheless, developing software of a predetermined quality in a predictable fashion can only be achieved with systematic development processes and the use of engineering principles. Thus, systematic development processes for this domain are needed urgently. This article presents a method for the design of an adaptable software development process based on existing practices from related domains, industrial piloting, and expert knowledge. First results of the application of the method for the wireless Internet services domain are described. The benefit for the reader is twofold: the article describes a validated method on how to gain process knowledge for an upcoming field fast and incrementally. Furthermore, first results of the process design for the wireless Internet services domain are given.

The Open Broadband Access Network (OBAN)1 project introduces an innovative approach to establish a broadband mobile network in line with present B3G visions.This paper describes the end-to-end OBAN simulator that has been developed with the aim to evaluate and quantitatively measure performance related to user's mobility, in a scenario where security is vital and there is need to be able to perform fast handover while ensuring security.A set of meaningful performance metrics is identified and measured in the simulator at application level, to model and assess the behavior of the different proposed solutions.The first part of the paper provides an overview of the OBAN architecture and the description of the models developed to simulate it, with particular focus on secure procedures for network access and user mobility. The second part describes the reference simulation scenarios, a summary of the results achieved and the relevant conclusions.