Riadh Robbana

University of Carthage | UCAR · National Institute of Applied Sciences and Technology

The formal Event-B method makes it possible to obtain systems or software correct by construction. The modeling activity aims to establish formal models in Event-B. As for the proof activity, it aims at correcting these models. A proven Event-B model is not necessarily valid. We propose to open the Event-B formal method on PDDL in order to further...

We present in this paper Phi, a generic microservices-based Big Data architecture dedicated to complex multi-layered systems, that rallies multiple machine learning jobs, stream and batch processing. We show how to apply our architecture to an adaptive e-learning application that adjusts its recommendation to the emotions of the learner on the spot...

Cloud computing is a new technology, providing different online resources and services to users. Load balancing has become an interesting research area in this field. A few existing scheduling algorithms can maintain load balancing and provide better strategies through efficient job scheduling and resource allocation techniques as well. In order to...

Big Data systems are now present in almost all mature organizations and not just IT focused ones. From luxury hotels to health care organizations, data storage and processing is witnessing a huge technological improvement thanks to the extensive research that is being conducted to improve these two areas. However, there is a lack of adaptability wh...

Hybrid Cloud environments allow the utilization of local resources in private Clouds with resources from public Clouds when needed. Such environments represent systems with high failure rates because they feature heterogeneous components, a large number of servers with intensive workload are built as complex architectures. For these reasons, the av...

Big Data technologies and approaches have an important impact on the organization and governance of the enterprise. With such a high volume of structured & unstructured data, real time and mutualization needs, it is quite complicated to keep a high quality of data by respecting the governance rules and best practices. In addition, new team roles an...

Quality of web service becomes more and more interesting as a distinguishing criterion to select a unique web service from all candidate ones. The quality assessment issue, especially regarding the volatility of the web services environment, is one among the main challenges in this context. In this paper, we propose a service-based system for web s...

One of the most critical properties that must be ensured to have a secure electronic voting is verifiability. Political parties, observers, and especially voters want to be able to verify that all eligible votes are cast as intended and counted as cast without compromising votes secrecy or voters privacy. Over the past few decades, an important num...

With the immutability property and decentralized architecture, Blockchain technology is considered as a revolution for several topics. For electronic voting, it can be used to ensure voter privacy, the integrity of votes, and the verifiability of vote results. More precisely permissioned Blockchains could be the solution for many of the e-voting is...

Blockchain provides the possibility to design new types of applications and systems that allow their users to store data in a secure and transparent way. In this paper, we design a fully verifiable online electronic voting protocol using a blockchain. Our e-voting protocol, called VYV for Verify-Your-Vote, involves cryptographic primitives based on...

Cloud computing has recently emerged as a new paradigm for hosting and delivering services over the Internet. It is an attracting technology in the eld of computer science since it allows starting from the small and increases resources only when there is a rise in service demand. Load balancing can improve the Quality of Service (QoS) metrics, incl...

Resource arbitration is a fundamental problem in communication and computing system design. Thus, a fast and efficient arbitration algorithm is one of the most dominant factors for high performance networks-on-chip (NoCs) and ensuring their reliability and performance is highly required. In this context, we propose, a formal model for the analysis...

As the number of devices increases in a single chip, the importance of fast and powerful arbiters is more and more critical. A fast and efficient arbiter is one of the most dominant factors for high performance Systems-on-Chip(SoCs). Round-Robin and TDMA arbitration protocols are considered as the most widely adopted scheduling algorithms, in parti...

The PDDL language is used to formally describe planning problems. It has tools called planners to solve planning problems described in PDDL. Equally, it has plan validation tools to validate the solution plans. Our automatic approach to transform a planning problem written in PDDL to Event-B method allows the use of the correct-by-construction para...

In digital system design, control access protocols are used to allocate shared resources. Whenever a resource, such as a bus is shared, an arbiter is required to assign the access to the resource at a particular time. In SoC (System on Chip) architectures, the design, analysis and implementation of such arbiter, are becoming increasingly important...

This poster has been presented in AICCSA conference as a support for an accepted paper with the same title.

This paper is about conformance testing of timed pushdown automata with inputs and outputs (TPAIO), that specify both stack and clock constraints. TPAIO are used as a model for timed recursive programs. This paper proposes a novel method of off-line test generation from deterministic TPAIO. In this context, a first problem is to resolve the clock c...

Performing runtime verification of composite web services is one of the actual main research challenges. This paper presents a formal approach for dynamically enforcing security policies on web services choreographies. We define a security framework for monitoring choreographed web services by inlining a monitor that checks whether a choreography a...

A Wireless Sensor Network (WSN) is a type of ad-hoc networks. WSN are characterized by severely constrained computational and energy resources, and an ad-hoc operational environment. Due to inherent resource and computing constraints, security in sensor networks poses dierent challenges comparing to traditional network computer security. To ensure...

In this paper, a new method is developed to generate automatically robustness test cases. We focus on security protocols for wireless sensor network (WSN) which is related to ad-hoc network. The testing process can announce if the WSN using a security protocol is robust or not in a hostile environment.

A Publicly Verifiable Secret Sharing (PVSS) scheme allows anyone to verify the validity of the shares computed and distributed by a dealer. The idea of PVSS was introduced by Stadler in [18] where he presented a PVSS scheme based on Discrete Logarithm. Later, several PVSS schemes were proposed. In [2], Behnad and Eghlidos present an interesting PVS...

Noninterference is a strong security policy that enforces confidentiality and integrity. Many solutions are proposed in the state of the art for verifying this policy in programs, but few tools are proposed to implement it. In this paper, we define a high-level model called Component Information Flow, and we develop the tools that simplify distribu...

In this paper, we are interested in generating test cases for duration systems with respect to coverage criteria. Duration systems are an extension of real-time systems for which delays that separate events depend on the accumulated times spent by the computation at some particular locations of the system. We present a test generation method for du...

Coercion resistance is the most effective property to fight coercive attacks in Internet elections. This notion was introduced by Juels, Catalano, and Jakobsson (JCJ) at WPES 2005 together with a voting protocol that satisfies such a stringent security requirement. Unfortunately, their scheme has a quadratic complexity (the overhead for tallying au...

La construction de systèmes distribués sécurisés est une tâche complexe et très coûteuse. Elle fait appel à des compétences dans des domaines variés : algorithmique distribuée, sécurité informatique, cryptographie, génie logiciel, etc. En particulier, l'implémentation de la propriété de non-interférence qui permet d'assurer une sécurité de bout en...

Automating the construction of secure distributed systems becomes necessary. Indeed, developing security code requires a deep expertise and verifying that the developed code respects the specified policy is a tedious task. In this paper, we define a toolkit called CIF (Component Information Flow) that automates the development of secure distributed...

Coercion-resistance is the most effective property to fight coercive attacks in Internet elections. This notion was introduced by Juels, Catalano, and Jakobsson (JCJ) at WPES 2005 together with a voting protocol that satisfies such a stringent security requirement. Unfortunately, their scheme has a quadratic complexity (the overhead for tallying au...

This paper deals with systems verification techniques, using Bounded Model Checking (BMC). We present a new approach that combines BMC with symmetry reduction techniques. Our goal is to reduce the number of transition sequences, which can be handled by a SAT solver, used in the resolution of verification problems. In this paper, we generate a reduc...

La construction de systèmes distribués sécurisés est une tâche complexe et très coûteuse. Elle fait appel à des compétences dans des domaines variés : algorithmique distri- buée, sécurité informatique et cryptographie, génie logiciel... Une approche pour pallier à cette difficulté consiste à introduire des abstractions de programmation et des outil...

We consider the verification problem of programs containing the following complex features: (1) dynamic creation of parallel threads, (2) synchronisation between parallel threads via global variables, (3) (possibly recursive) procedure calls, and (4) integer variables. The configurations of such programs are represented by terms, and their transiti...

Intelligent, embedded systems such as autonomous robots and other industrial systems are becoming increasingly more heterogeneous with respect to the platforms on which they are implemented, and thus the software architecture more complex to design and analyse. In this context, it is important to have well-defined design methodologies which should...

In this paper, we are interested in testing duration systems. Duration systems are an extension of real-time systems for which delays that separate events depend on the accumulated times spent by the computation at some particular locations of the system. We present an automatic testing method for duration systems that uses the approximation method...

In this paper, we are interested in testing duration systems. Duration systems are an extension of real-time systems for which delays that separate events depend on the accumulated times spent by the computation at some particular locations of the system. We present a test generation method for nondeterministic duration systems that uses the approx...

Clustering is an active research topic in data mining and different methods have been proposed in the literature. Most of these methods are based on the use of a distance measure defined either on numerical attributes or on categorical attributes. However, in fields such as road traffic and medicine, datasets are composed of numerical and categoric...

In this paper, we are interested in testing duration systems. Duration systems are an extension of real-time systems for which delays that separate events depend on the accumulated times spent by the computation at some particular locations of the system. We present an automatic testing method for duration systems that uses the test purposes concep...

Timestamping [1] is a cryptographic technique for adding a reliable date to a document in order to prove its existence at a given time. Several solutions of timestamping exist. They are all based on cryptographic techniques as digital signatures and hash functions. However, with the increase of computing power and the evolution of cryptanalysis met...

Testing is an important validation activity particularly for real-time systems. We are interested to testing duration systems which are an extension of real-time systems, we consider that the specification of duration systems is described by a duration graphs. Duration graphs are an extension of timed graphs and are suitable for modeling the accumu...

We are interested in generating tests for duration systems modeling real-time systems. The specification of a duration system is given as a duration graph. Duration graphs are an extension of timed graphs and are suitable for modeling the accumulated times spent by computations within the considered duration system. In this paper, we present a meth...

International audience Observational theories are a generalization of first-order theories where two objects are observationally equal if they cannot be distinguished by experiments with observable results. Such experiments, called contexts, are usually infinite. Therfore, we consider a special finite set of contexts, called cover-contexts, ''\emph...

We consider the problem of verifying invariance properties for duration systems. Such systems are (extended) timed graphs with duration variables. They are especially suitable for describing real time schedulers. However, for this kind of systems, the verification problem of invariance properties is in general undecidable. We propose an over approx...

Summary form only given. In symbolic model checking of untimed systems, the general approach is based on BDDs (Binary Decision Diagrams) representation. Concurrently, TDGs (typed Decision Graphs) were proposed in another context, bring a better profit of capacity memory. However, the symbolic method do not easily generalize to models that contain v...

Summary form only given. Duration graphs are an extension of timed graphs supplied with a finite set of continuous real variables that can be stopped in some locations (rate=0) and resumed in other locations (rate=1). These variables are called: duration variables. Duration graphs are suitable for modelling real time schedulers with preemption whic...

Summary form only given. Several applications generate complicated finite states systems as the design of the communications protocols and the design of circuits. When the number of states of a system is large, it is difficult to determine manually if such a system is correct or not. The checking or model checking proposed in parallel by both (Clar...

We consider the verification problem of invariance properties for timed systems modeled by (extended) Timed Graphs with duration variables. This problem is in general case undecidable. Nevertheless we give in this paper a technique extending a given system into another one containing the initial computations as well as additional ones. Then we defi...

Les systèmes hybrides sont des systèmes qui combinent des composantes discrètes et des composantes continues. Les composantes continues peuvent représenter un environnement physique obéissant à des règles de changement continu, par contre les composantes discrètes peuvent représenter des contrôleurs discrets qui sondent et manipulent les composante...

We address the problem of verifying untimed -regular properties for a subclass of linear hybrid systems, i.e., finite transition graphs supplied with real-valued variables that change continuously with integer rates at each control location. The systems we consider are systems with two variables, one of them must be monotonic (e.g., with rates eith...

We relate two different approaches for the specification and verification of hybrid systems. The first one is logic-based and uses the framework of the Calculus of Durations (CoD), the second one is automata-based and uses algorithmic analysis techniques for hybrid automata. Fragments of CoD have been identified in [13, 19] for the description of c...

We address the verification problem of invariance properties for hybrid systems. We consider as general models of hybrid systems finite automata, supplied with (unbounded) discrete data structures and continuous variables. We focus on the case of systems manipulating discrete counters and one pushdown stack, and on the other hand, constant slope co...

We address the problem of the specification and the verification of processes with infinite-state spaces. Many relevant properties for such processes involve constraints on numbers of occurrences of events (truth of propositions). These properties are nonregular and hence, they are not expressible neither in the usual logics of processes nor by fin...

We address the verification problem of infinite timed systems. We consider context-free timed systems defined as a generalization of the (regular) timed graphs [ACD90]. Then, we propose decision procedures for the verification of invariance properties of these systems, expressed by means of observation variables. These variables record relevant inf...

We address the problem of the specification and the verification of processes with infinite-state spaces. Many relevant properties for such processes involve constraints on numbers of occurrences of events (truth of propositions). These properties are nonregular and hence, they are not expressible neither in the usual logics of processes nor by fin...

We consider the verification problem of invariance properties for timed systems modeled by (extended) Timed Graphs with duration variables. While clocks of a Timed Graph can be seen as continuous (real valued) variables with rates 1 at each control location of the system, duration variables (also called integrators) are continuous variables having...

We consider the verification problem of invariance properties for timed systems modeled by (extended) Timed Graphs with duration variables. While clocks of a Timed Graph can be seen as continuous (real valued) variables with rates 1 at each control location of the system, duration variables (also called integrators) are continuous variables having...