Ihab Sbeity

PEPS2007 - Stochastic Automata Networks Software Tool

We give an overview of GRIP, a symmetry reduction tool for the probabilistic model checker PRISM, together with experimental results for a selection of example specifications.This work presents the new version of PEPS software tool, designed for solving models expressed using Stochastic Automata Networks (SAN). The SAN formalism is historically the first Markovian structured formalism employing Tensor Algebra. PEPS tool was first launched in the late 80’s and it’s still a live project, therefore a short timeline of its previous versions, as well as the new features included in version 2015, are presented, such as an efficient and powerful just-in-time function evaluation.

Phase-type distributions in stochastic automata networks

Abstract Stochastic automata networks (S ans ) are high-level formalisms for modeling very large and complex Markov chains in a compact and structured manner. To date, the exponential distribution has been the only distribution used to model the passage of time in the evolution of the different S an components. In this paper we show how phase-type distributions may be incorporated into S ans thereby providing the wherewithal by which arbitrary distributions can be used which in turn leads to an improved ability for more accurately modeling numerous real phenomena. The approach we develop is to take a S an model containing phase-type distributions and to translate it into another, stochastically equivalent, S an model having only exponential distributions. In the S an formalism, it is the events that are responsible for firing transitions and our procedure is to associate a stochastic automaton with each event having a phase-type distribution. This automaton models the distribution of time until the event occurs. In this way, the size of the elementary matrices remain small, because the size of the automata are small: the automata are either those of the original S an , or are those associated with the phase-type events and are of size k , the number of phases in the representation of the distribution.

MSpace: An Emergent Approach, Modelling and Exploring Mutable Business-Entities

Roughly speaking, in the literature objects or agents evolutions are usually handled using objects/agents moving models and multi-dimensional representation. Most of traditional and powerful analytical systems prefer using multi-dimensional data structure that facilitating data/object representation and tracking. Those systems became popular in companies and industries that store and interpret historical information for decision-making purposes, e.g. data warehousing.

CityPro: city-surveillance collaborative platform

Day by day, modern cities face a big challenge in terms of public safety and security. In the city, the surveillance systems mostly use video surveillance techniques, they incorporate thousands of cameras and relay to high-speed networking infrastructures. Moreover, in a city, there exist multiple computerised standalone systems that operate independently each other, e.g., banking systems, customs, and hospitals. These systems generate huge datasets. The collected data stimulate a gigantic mine of scattered information. A smart city is a city that intelligently benefits from such omnipresent systems. This paper presents an integrated platform to gather multiple existing systems in a city. The platform consists of a collaborative surveillance system, called CityPro. The proposed architecture is intended to protect and monitor people and public infrastructures, such as bridges, roads, buildings, etc.; it is designed to deal with and prevent abnormal activities like terrorist attacks. CityPro is expected to operate in live-mode by using the city digital-infrastructures. At the end of this paper, a typical case study is given, and challenges and future works are also discussed.

CityPro; An Integrated City-protection Collaborative Platform

Abstract Its a big challenge to deal with security in a city. Technology advancements are influencing our life, cities are evolving, and modern cities are referring more and more to digital technologies. Currently, a huge amount of standalone independent-systems operate in the city, their goal is to satisfy some business activities, e.g. banking, customs, hospitals, etc. Data collected by these systems represents, if integrated, a key element in any decision making process. This paper presents a, working, smart collaborative platform to integrate multiple systems to serve the surveillance activities in a city or country. It consists of a collaborative surveillance system, called CityPro. The architecture that we propose is a future vision to protect people and monitor public infrastructures, such as bridges, roads, buildings, etc.; it is designed to deal with and/or prevent abnormal activities like terrorist attacks. CityPro is expected to operate in live-mode by using (intended to use) city adapted IT-infrastructures. At the end of this paper, a typical case study is given, and challenges and future works are also discussed.

Towards service-based approach: building huge software architectural design

Software architecture, as a discipline, draws vocabulary like rules, paradigm, pattern that help to build software systems. In this paper we first provide an introduction to the emerging field of software architecture. Many software architecture approaches were introduced; they draw different paths and methodologies to build software systems. This paper forms a survey for some of these approaches with a focus on the decomposition approach in terms of requirements and data-attributes. In this paper we will discuss a new formal service-based software decomposition approach. This approach consists of a micro-phased process. We begin by considering the front-end services, the common and modern architectural styles upon which many systems are currently based; we focus on their business profiles, non-atomic business data-items and business rules. Our proposed approach represents the first and crucial design stage in the software engineering process. It consists of building the overall software architectures that could be represented as an oriented and purposed graph. At the end, we demonstrate that the process is plausible and easy to apply. We also state that micro-phases may be reiterated and executed without strict ordering. Meta-modelling and computerising such approach represents our future works.

Software performance engineering using UML2SAN: Deadlock prediction of funds transfer

In order to allow software designers to determine the performance of software during design, Connie Smith has introduced the concept of Software Performance Engineering (SPE). The idea is to bring performance evaluation into the software design process. Several approaches have been proposed to provide such techniques. Some of them propose to derive from a UML (Unified Modeling Language) model a performance model. UML2SAN is one of the most recent works in SPE, that permits to generate a performance model (SAN: Stochastic Automata Network) from UML specifications. In this paper, we verify the convenience of UML2SAN by predicting deadlock of transfer funds in a banking system during the design phase.