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International audience; Digital Twin (DT) is one of the pillars of modern information technologies that plays an important role on industry's digitalization. A DT is composed of a real physical object, a virtual abstraction of the object and a bidirectional data flow between the physical and virtual components. This paper presents a DT-based tool, called TaS, to easily test and simulate IoT environments. The objective is to improve the testing methodologies in IoT systems to evaluate the possible impact of it on the physical world. We provide the conditions to test, predict errors and stress application depending on hardware, software and real world physical process. The tool is based on the DT concept in order to detect and predict failures in evolving IoT environments. In particular, the way to prepare the DT to support fault injection and cybersecurity threats is analyzed. The TaS tool is tested through an industrial case study, the Intelligent Transport System (ITS) provided by the INDRA company. Results of experiments are presented that show that our DT is closely linked to the real world.

International audience; Testing and monitoring the effectiveness of security policies under pervasive system architectures is still a major challenging problem for the research community as well as industrials. The inherent characteristics of these systems such as the heterogeneous communicating devices and the multiple used technologies make the burden more overwhelming when dealing with security measures and policies. This paper aims to bridge this gap through the introduction of a formal design of security policies to make security monitoring operation more efficient. Hence, a formal framework is proposed to actively test web-based systems, as an example of these pervasive architectures. The goal of our technique is to check the compliance of the targeted web application to a set of generic security requirements such as confidentiality, integrity and availability as well as to a set of user-related security constraints. Our approach has been applied to a real industrial electronic voting application provided by the Scytl company. Several experiments show the merit of our technique in verifying the correctness of security measures of the targeted application. This framework is part of the INTER-TRUST solution intended to ensure secure inter-operation between communicating systems and provide solutions to test and monitor them

International audience; Ensuring the correctness of complex distributed software systems is a challenging task, the issue of building frameworks for developing such safe and correct systems still remains a difficult issue. Where test coverage is dissatisfying, formal analysis grants much higher potential to discover bugs during the development phase. This paper presents a framework for formal verification of complex systems based on standardized test objectives. The framework integrates a transformation of test objectives into formal properties that are verified on the system by model checking. The overall proposed approach for formal verification is evaluated by the application to the standard European Train Control System (ETCS). Some critical safety properties have been proved on the model, ensuring that the model is correct and reliable

International audience; This paper presents an approach for the automated testing of Enterprise Resource Planning (ERP) systems. ERPs are complex software systems that provide a chain management covering all corporate activities. Testing of these systems is a complex task given the close interrelation between the functionalities of system modules. Test automation is also an important issue, in order to reduce testing time and cost. To this end, our approach for the automation of ERP systems testing, is based on the system modeling as a set of business processes to meet the needs of the business and reduce, for this purpose, the risks of errors. The methodology used in this context is to combine the system modeling and the tools to manage automation of ERP-tests. Following this approach, from the basic requirements, a number of test purposes are defined and test cases are generated using a test generation tool, which are then run on the ERP system. In order to illustrate the application of the proposed method , test experiments have been performed on a real case study, the ERP ODOO

International audience; In a context in which the Internet provides a platform used to distribute contents, new actors have emerged in the business of multimedia services, who have taken advantage of this new platform to deliver services at lower cost. However, the Internet does not provide a reliable platform to distribute content, which justifies the development of technology that ensures high levels of quality to the end user of the service. This work presents the advances developed in this direction in the context of the Celtic+ Project NOTTS: first, a new Quality of Experience (QoE) evaluation framework that incorporates economical variables in the analysis; second, the implementation of the before mentioned framework in order to analyze how the user's decisions impact of the QoE; and lastly, an emulation platform for Over-The-Top Services (OTT), used to emulate the behavior of these services in real Internet scenarios and to apply the implementation of the framework proposed

International audience; Requests to improve the quality of software are increasing due to the competition in software industry and the complexity of software development integrating multiple technology domains (e.g., IoT, Big Data, Cloud, Artificial Intelligence, Security Technologies). Measurements collection and analysis is key activity to assess software quality during its development live-cycle. To optimize this activity, our main idea is to periodically select relevant measures to be executed (among a set of possible measures) and automatize their analysis by using a dedicated tool. The proposed solution is integrated in a whole PaaS platform called MEASURE. The tools supporting this activity are Software Metric Suggester tool that recommends metrics of interest according several software development constraints and based on artificial intelligence and MINT tool that correlates collected measurements and provides near real-time recommendations to software development stakeholders (i.e. DevOps team, project manager, human resources manager etc.) to improve the quality of the development process. To illustrate the efficiency of both tools, we created different scenarios on which both approaches are applied. Results show that both tools are complementary and can be used to improve the software development process and thus the final software quality

International audience; This paper presents a study of existing threat detection techniques in cloud computing, together with an experimental evaluation of a subset of them. We consider the threats defined in the Cloud Security Alliance (CSA) report as well as the techniques for their detection, starting from classical signature-based approaches and finishing with recent machine learning based techniques. This paper also contains an analysis of original results presented in international conferences, published as journal papers, Internet resources, and standards. The main contributions of the study include: (1) providing a closer relationship between top threats in cloud computing and known detection techniques; (2) evaluating existing detection techniques concerning cloud computing principles and security challenges nowadays; and (3) reviewing commonly utilised datasets and their association with threats in the last five years. As existing detection techniques tend to target specific threats (or their groups), we also present the experimental evaluation of the applicability of known detection approaches against non-targeted threat groups

International audience; To improve software quality, it is necessary to introduce new metrics with the required detail and increased expressive power, in order to provide valuable information to the different actors of software development. In this paper we present two approaches based on metrics that contribute to improve software quality development. Both approaches are complementary and are focused on the combination, reuse and correlation of metrics. They suggest to the user indications of how to reuse metrics and provide recommendations after the application of metrics correlation. They have been applied to selected metrics on software maintainability, safety, security etc. The approaches have been implemented in two tools, Metrics Suggester and MINT. Both approaches and tools are part of the ITEA3 MEASURE project and they have been integrated into the project platform. To illustrate its application we have created different scenarios on which both approaches are applied. Results show that both approaches are complementary and can be used to improve the software process

International audience; This paper presents a security assurance platform to monitor and control the security in the context of multi-cloud applications. Indeed, this property is a crucial issue in multi cloud-based environments where many aspects need to be faced, including risk management, data privacy and isolation, security-by-design applications, and vulnerability scans. Moreover, it also becomes necessary to have an efficient system that interrelates and operates all security controls that are configured and executed independently on each component of the system. In addition, as new attacks emerge every day, threat detection systems play a fundamental role in security monitoring schemes, identifying possible attacks. These systems handle an enormous volume of data, as they detect unknown malware by monitoring different activities from different points of observation, as well as adapting to new attack strategies and considering techniques to detect malicious behaviors and react accordingly. In this paper, we describe a monitoring platform for securing multi-cloud applications, from a Service Level Agreement perspective. Moreover, we present a case study depicting the multi-cloud monitoring of a smart-city transport application for the citizens of Tampere, Finland. Considering the nature of the application under study, the service requires continuous execution and availability functionalities, as end-users may utilize the service at any time

International audience; The paper presents a Finite State Machine (FSM) based approach for deriving tests with reduced complexity, under the White Box testing assumption where all the faulty implementations are explicitly enumerated. The specification and implementation FSMs are assumed to be initialized, i.e., each possibly partial and (non-observable) nondeterministic FSM has a reliable reset. The proposed technique is illustrated by the application to a communication protocol

International audience; The issue of data security and privacy in multi-cloud based environments requires different solutions for implementing and enforcing security policies. In these environments, many security aspects must be faced, such as security-by-design, risk management, data privacy and isolation, and vulnerability scans. Moreover, it also becomes necessary to have a system that interrelates and operates all security controls which are configured and executed independently on each component of the application (service) being secured and monitored. In addition, thanks to the large diffusion of cloud computing systems, new attacks are emerging, so threat detection systems play a key role in the security schemes, identifying possible attacks. These systems handle an enormous volume of information as they detect unknown malicious activities by monitoring different events from different points of observation, as well as adapting to new attack strategies and considering techniques to detect malicious behaviors and react accordingly. To target this issue, we propose in the context of the MUSA EU Horizon 2020 project, a security assurance platform that allows monitoring the multi-cloud application deployed in different Cloud Server Providers (CSPs). It detects potential deviations from security Server Level Agreements (A formal, negotiated document that defines in quantitative and qualitative terms the service being offered to a Cloud Service Client (CSC).) (SLAs) and triggers countermeasures to enforce security during application runtime

International audience; As 'computational' systems grow in usage, an aspect often required to be enhanced is their energetic consumption. This paper presents a methodology for measuring and optimizing the energy spent by the embedded software. The proposed approach relies on the use and manipulation of state models that can be effectively obtained from the source code. The network load/utilization is considered as an optimization criterion for the overall software energy consumption

International audience; In this paper, we present a framework for evaluating the QoE of a service that includes functional and non-functional service requirements. Non-functional requirements are classified into objective, subjective, and business parameters that affect Quality of Service (QoS), Quality of Experience (QoE), and Quality of Business (QoBiz), correspondingly. As those metrics have a strong dependency between each other, we discuss how the QoE of a web-based Over-The-Top service (OTT) can be evaluated taking into account subjective, objective and business parameters. The functional service behavior is described by an Extended Finite State Machine (EFSM) in which non-functional objective, subjective and business-related parameters are tracked using context variables and corresponding updating functions. These parameters are used to evaluate the QoE of the service. We show that the corresponding model allows to keep a track of a user-service interaction. Moreover, the model of the service integrates subjective, objective and business parameters, and thus, can be applied to the QoE evaluation of any OTT service

International audience; This chapter introduces the overall concept of multimedia Quality of Experience (QoE) over the Internet. It presents all the elements of multimedia QoE ecosystem and emphasizes their roles in determining the user satisfaction. The chapter also presents different multimedia transmission components and how these components contribute to successful transmission of the media content. In addition, some key performance indicators relevant to the multimedia QoE are presented with more emphasis on network and application level indicators. Furthermore, different QoE estimation methods and techniques along with QoS/QoE learning algorithms are presented. Finally, the chapter includes some of the future challenges and issues related to multimedia QoE

International audience; Supporting real time video transmission over wireless networks is very challenging. The video flow characteristics can be vulnerable to the time-varying channel conditions and the unreliability of the MAC (Medium Access Control) can substantially degrade Quality of Experience (QoE) in wireless networks. QoE reflects the satisfaction level of a user towards a particular service or application. It can be a valuable input to service providers and help them to enhance the quality of the overall system. In this work, we present a methodology and a system based on Random Neural Network (RNN) to analyze the impact of different MAC-level objective parameters on video QoE over IEEE 802.11n wireless networks. At first, subjective tests are performed to correlate MAC-level parameters with user's perceived video QoE. Secondly, we propose a RNN technique to estimate the impact of these parameters on video QoE. The experimental results show that the proposed method can effectively measure the impact of MAC-level parameters on video QoE. The acceptable correlation between subjective QoE and estimated QoE verifies the validity of the obtained results.

Most of the work related to QoE maps objective variables (QoS-related) into a single one that predicts the quality the user perceives. In this paper we present a new approach to model multimedia OTT services, integrating not only the functional aspects of the service but also non-functional variables, which are classified into objective, subjective and business-related. Non-functional metrics might affect the Quality of Service (QoS), Quality of Experience (QoE) and Quality of Business (QoBiz) correspondingly. We also discuss how all these variables can be taken into account to predict the QoE of the service being studied. The functional requirements are modeled into a Timed Extended Finite State Machine (TEFSM), which is augmented with context variables (and their updating functions) representing non-functional requirements related to QoS, QoE and QoBiz. We use these parameters to evaluate the QoE using a trace model derived from the TEFSM previously built.

International audience; Testing embedded systems to find errors and to validate that the implemented system is as per the specifications and requirements has become an important part of the system design. The research community has proposed several formal approaches these last years, but most of them only consider the control portion of the protocol neglecting the data portions, or are confronted with an overloaded amount of data values to consider. In this chapter, we present a novel approach to formally model protocol properties of embedded application in terms of Input-Output Symbolic Transition Systems (IOSTS) and show how they can be tested on real execution traces taking into account the data and control portions. These properties can be designed to test the conformance of a protocol as well as security aspects. A parametric trace slicing approach is presented to match trace and property. This chapter is illustrated by an application to a set of real execution traces extracted from a real automotive Bluetooth framework with functional and security properties

International audience; This paper presents a new approach to perform passive testing based on the analysis of the control and data part of the system under test. Passive testing techniques are based on the observation and verification of properties on the behaviour of a system without interfering with its normal operation. Many passive testing techniques consider only the control part of the system and neglect data, or are confronted with an overwhelming amount of data values to process. In our approach, we consider control and data parts by integrating the concepts of symbolic execution and we improve trace analysis by introducing trace slicing techniques. Properties are described using Input-Output Symbolic Transition Systems (IOSTSs) and we illustrate in the paper how they can be tested on real execution traces optimizing the trace analysis. These properties can be designed to test the functional conformance of a protocol as well as security properties. In addition to the theoretical approach, we have developed a software tool that implements the algorithms presented in this paper. Finally, as a proof of concept of our approach and tool we have applied the techniques to a real-life case study: the SIP protocol. In particular, the proposed techniques are applied to a set of real execution traces extracted from an IMS/SIP architecture

This paper presents the work developed by the joint ISO/ITU-T working group on “Formal Methods in Conformance Testing” (FMCT) in order to obtain a future standard. It concerns several areas of conformance testing: terminology, testing concepts, test architecture, specification languages for tests and test generation methods. The influence of FMCT on testing methodology is also analysed and future trends in the area are addressed.

The aim of this tutorial is to present an overview of conformance testing methods for SDL systems. These methods can be classified into two main groups: those whose intent is the totally automated test generation from the SDL system specification and those that provide interactive test generation methods. We present some of the more representative methods illustrating their application by a common example. This example, the Inres protocol and service, will facilitate the comparison of the methods with respect to SDL and test notations, restrictions on the language, results of the application to the protocol and the tools supporting the methods.

International audience; Security is a critical issue in dynamic and open distributed environments such as network-based services or wireless networks. To ensure that a certain level of security is maintained in such environments, the system behavior has to be restrained by a security policy in order to regulate the nature and the context of actions that can be performed within the system, according to specific roles. In this paper, we propose a passive testing approach that permits to check whether a system respects its security policy. To reach this goal, we specify this policy using 'Nomad' formal language which is based on deontic and temporal logics. This language is well adapted to passive testing methods that aim to analyze collected system execution traces in order to give a verdict about their conformity with to the system security requirements. Finally, we apply our methodology to an industrial case study provided by SAP group to demonstrate its reliability

The future of wireless networks evolves toward more simple ways for users to get connected while on the move. In this perspective, Wireless Mesh Networks constitutes one of the key technologies for next generation wireless networks. In this paper we present LCMP, a new protocol for client management in wireless mesh networks. LCMP performs on-demand path setup for clients and supports clients mobility by introducing new light mechanisms that take full advantage of the mesh architecture. The work on LCMP and mesh routing is still in progress at LOMNT laboratory. In this papel; we highlight some ongoing work.

The development of test cases is an important issue for testing software, communication protocols and other reactive systems. A number of methods are known for the development of a test suite based on a formal specification given in the form of a finite state machine. Well-known methods are called the W, Wp, UIO, UIOv, DS, H and HIS test derivation methods. These methods have been extensively used by research community in the last years; however no proper comparison has been made between them. In this paper, we experiment with these methods to assess their complexity, applicability, completeness, fault detection capability, length and derivation time of their test suites. The experiments are conducted on randomly generated specifications and on a realistic protocol called the simple connection protocol.

This paper presents an overview of the work we have developed at INT on different approaches to protocol and service testing. It is related to performing tests of communication protocols and telecommunication services based on techniques, such as, active test generation, passive testing, embedded testing and test execution.

Publisher Summary This chapter presents the application of a test generation method to the testing of the Service Specific Connection Oriented Protocol (SSCOP) for asynchronous transfer mode (ATM) networks. Test sequences have been generated automatically in an optimized and nonoptimized way from the Specification and Description Language (SDL) specification of the protocol. To illustrate the advantages of the presented method, the chapter translates a test sequence generated using the method into the message sequence chart (MSC) formalism to show that tests obtained in an automatic way have the same form as tests obtained manually as is the case for one of the tests scripts. The increasing complexity of telecommunication systems based on ATM networks requires development of testing techniques to be applied to their services and protocols. Telecommunication industries have become conscious of the importance of the testing phase in the development of distributed software applications. The chapter explains the intensive research developed in the past years to automatize the test generation procedure. This research activity has produced a great number of test-generation methods that have been integrated into existing tools and have been applied successfully in several industrial projects.

This paper presents a summary of some issues that appear to be relevant to testing theory and its applications. These issues are linked to formal methods used for test derivation, to the semantic models chosen to represent these specifications, and to the appropriate techniques needed for selecting a reasonable test effort. A discussion is presented in a polemical fashion trying to illustrate the problems related to the translation of one model into another, to non deterministic and partially specified systems, to the size of the specifications and test suites and the ways to reduce them.

This paper presents a verification method based on a modal logic for the LOTOS language. The method has been inspired by the works on verification methods for the CCS language. These works are extended in this paper to the LOTOS operators (parallel, enabling and disabling). It is also shown how to decompose a general formula into smaller parts in order to be verified by parts of the program which describes a system. A full version of this paper is presented in [1].

This paper presents exhaustive analysis and simulation for distributed systems validation. Exhaustive analysis makes possible to detect quickly several types of errors, for instance, unspecified reception of signals, errors in timer management, deadlock, errors in precedence, etc. But, in general, exhaustive analysis can only be applied to a simplified model of the distributed system due to the state explosion problem. On the other hand, simulation permits accurate tests and confronts the distributed system to complex situations. We think both forms of validation are complementary. Validation was done on systems specified in the SDL language, using OVAL, a tool for specification validation developed at CNET, Paris A. This tool allows exhaustive analysis and simulation of SDL specified systems. We illustrate our results with several examples.